Patent Application
20220184148
The ASCII file, entitled 91125SequenceListing.txt, created on Jan. 20, 2022 comprising 1,286 bytes, submitted concurrently with the filing of this application is incorporated herein by reference.
The present invention, in some embodiments thereof, relates to the microbiome and, more particularly, but not exclusively, to a method and apparatus for predicting a response of a subject to one or more agents by analysis of the microbiome.
The human in intestine carries a vast and diverse microbial ecosystem that has co-evolved with our species and is essential for human health. Mammals possess an ‘extended genome’ of millions of microbial genes located in the intestine: the microbiome. This multigenomic symbiosis is expressed at the proteomic and metabolic levels in the host and it has therefore been proposed that humans represent a vastly complex biological ‘superorganism’ in which part of the responsibility for host metabolic regulation is devolved to the microbial symbionts. Modern interpretation of the gut microbiome is based on a culture-independent, molecular view of the intestine provided by high-throughput genomic screening technologies. Also, the gut microbiome has been directly implicated in the etiopathogenesis of a number of pathological states as diverse as obesity, circulatory disease, inflammatory bowel diseases (IBDs) and autism. The gut microbiota also influences drug metabolism and toxicity, dietary calorific bioavailability, immune system conditioning and response, and post-surgical recovery. The implication is that quantitative analysis of the gut microbiome and its activities is essential for the generation of future personalized healthcare strategies and that the gut microbiome represents a fertile ground for the development of the next generation of therapeutic drug targets. It also implies that the gut microbiome may be directly modulated for the benefit of the host organism.
The gut microbiota therefore perform a large number of important roles that define the physiology of the host, such as immune system maturation, the intestinal response to epithelial cell injury, and xenobiotic and energy metabolism. In most mammals, the gut microbiome is dominated by four bacterial phyla that perform these tasks: Firmicutes, Bacteroidetes, Actinobacteria and Proteobacteria. The phylotype composition can be specific and stable in an individual, and in a 2-year interval an individual conserves over 60% of phylotypes of the gut microbiome. This implies that each host has a unique biological relationship with its gut microbiota, and by definition that this influences an individual's risk of disease.
Background art includes Payne et al., obesity reviews (2012) 13, 799-809; and Cowen et al The FASEB Journal. 2013; 27:224.
Additional background art includes US Patent Application No. 20100172874.
According to an aspect of some embodiments of the present invention there is provided a method of determining tolerance to an agent in a healthy subject, comprising:
(a) determining a signature of a microbiome in a sample of the healthy subject who has been subjected to the agent or condition; and
(b) comparing the signature of the microbiome of the healthy subject to at least one reference signature of a pathological microbiome, wherein when the signature of the microbiome of the healthy subject is statistically significantly similar to the reference signature of the pathological microbiome, it is indicative that the healthy subject is intolerant to the agent.
According to an aspect of some embodiments of the present invention there is provided a method of determining an effect of an agent on a microbiome of a healthy subject comprising:
(a) exposing the microbiome to the agent;
(b) comparing the signature of the microbiome following the exposing with a reference signature of a pathological microbiome, wherein when the signature of the microbiome is statistically significantly similar to the pathological microbiome reference signature, it is indicative that the agent has a deleterious effect on the microbiome.
According to an aspect of some embodiments of the present invention there is provided a method of determining tolerance to an artificial sweetener in a healthy subject comprising analyzing the amount of a microbe belonging to an order selected from the group consisting of bacteroidales order, Clostridilales order, Bactobacillales order, YS2 order, RF32 order, Erysipelotrichales order, Burkholderiales order and/or Campylobacterales order in a microbiome of the subject, wherein an amount of microbes of the Bacteroidales, Clostridilales, Bactobacillales and/or YS2 order above a predetermined level is indicative of a subject being tolerant to the artificial sweetener and an amount of microbes of the RF32, Erysipelotrichales, Burkholderiales and/or Campylobacterales order above a predetermined level is indicative of a subject being intolerant to the artificial sweetener.
According to an aspect of some embodiments of the present invention there is provided a method of determining tolerance to an artificial sweetener in a healthy subject comprising analyzing the amount of at least one microbe or class of microbes as set forth in Table 5 in a microbiome of the subject, wherein the amount of at least one of the microbes or the class of microbes above a predetermined level is indicative of a subject being intolerant to the artificial sweetener.
According to an aspect of some embodiments of the present invention there is provided a method of restoring the tolerance of a subject to an agent comprising administering to the subject an effective amount of a probiotic composition which comprises statistically significantly similar microbes to the non-pathological microbiome, thereby restoring the subjects tolerance to the agent.
According to an aspect of some embodiments of the present invention there is provided a probiotic composition, wherein a majority of the microbes of the composition are microbes of the bacteroidales order, the Clostridilales order, the Bactobacillales order and/or the YS2 order, the composition being formulated for rectal or oral administration.
According to an aspect of some embodiments of the present invention there is provided a method of restoring the tolerance of a subject to an artificial sweetener comprising administering to the subject an effective amount of probiotic composition of claim 42, thereby restoring the tolerance of the subject to the artificial sweetener.
According to an aspect of some embodiments of the present invention there is provided a method of restoring the tolerance of a subject to an artificial sweetener comprising administering to the subject an effective amount of antibiotic which reduces the relative abundance of a microbe being of the RF32, Erysipelotrichales, Burkholderiales and/or Campylobacterales order, thereby restoring the tolerance of the subject to the artificial sweetener.
According to an aspect of some embodiments of the present invention there is provided a method of restoring the tolerance of a subject to an artificial sweetener comprising administering to the subject an effective amount of antibiotic which reduces the relative amount of at least one microbe as set forth in Table 5, thereby restoring the tolerance of the subject to the artificial sweetener.
According to an aspect of some embodiments of the present invention there is provided a method of providing an antibiotic or probiotic treatment for a subject in need thereof comprising:
(a) analyzing the circadian rhythm of the microbiome of the subject;
(b) providing the antibiotic or probiotic treatment to the subject wherein the dose or time of administration of the antibiotic or probiotic treatment is selected based on the circadian rhythm of the microbiome of the subject.
According to an aspect of some embodiments of the present invention there is provided a kit for determining whether a subject is tolerant to an agent comprising:
(i) an agent which is capable of determining an amount of at least one microbiome component, wherein the level of the at least one microbiome component is significantly different in an agent-tolerant microbiome and an agent-intolerant microbiome; and
(ii) a pathological microbiome.
According to further features in the described preferred embodiments, the method further comprises comparing the signature of the microbiome following the exposing with a non-pathological microbiome reference signature, wherein when the signature of the microbiome is statistically significantly different to the non-pathological microbiome reference signature, it is indicative that the agent has a deleterious effect on the microbiome.
According to further features in the described preferred embodiments, the exposing is effected in vivo.
According to further features in the described preferred embodiments, the exposing is effected ex vivo.
According to further features in the described preferred embodiments, the method further comprises comparing the signature of the microbiome of the healthy subject to at least one non-pathological reference signature, wherein when the signature of the microbiome of the healthy subject is statistically significantly different to the at least one non-pathological reference signature, it is indicative that the healthy subject is intolerant to the agent.
According to further features in the described preferred embodiments, the agent is a substance.
According to further features in the described preferred embodiments, the agent is a condition.
According to further features in the described preferred embodiments, the substance is a food additive.
According to further features in the described preferred embodiments, the food additive is a preservative.
According to further features in the described preferred embodiments, the substance is an artificial sweetener.
According to further features in the described preferred embodiments, the condition is a change in sleep pattern.
According to further features in the described preferred embodiments, the condition is exposure to light.
According to further features in the described preferred embodiments, the condition is exposure to tobacco smoke or radiation.
According to further features in the described preferred embodiments, the substance is a therapeutic agent.
According to further features in the described preferred embodiments, the pathological microbiome is derived from a subject who has a disease.
According to further features in the described preferred embodiments, the disease is diabetes or pre-diabetes.
According to further features in the described preferred embodiments, the pathological microbiome is derived from a healthy subject who is intolerant to the agent.
According to further features in the described preferred embodiments, the d non-pathological microbiome is derived from a healthy subject who is tolerant to the agent.
According to further features in the described preferred embodiments, the artificial sweetener comprises a component selected from the group consisting of saccharin, steviol and Aspartame.
According to further features in the described preferred embodiments, the signature of a microbiome is a presence or level of microbes of the microbiome.
According to further features in the described preferred embodiments, the signature of a microbiome is a presence or level of genes of microbes of the microbiome.
According to further features in the described preferred embodiments, the signature of a microbiome is a product generated by microbes of the microbiome.
According to further features in the described preferred embodiments, the product is selected from the group consisting of a mRNA, a polypeptide, a carbohydrate and a metabolite.
According to further features in the described preferred embodiments, the product comprises short chain fatty acids (SCFAs).
According to further features in the described preferred embodiments, the method further comprises subjecting the subject to the agent prior to the analyzing.
According to further features in the described preferred embodiments, the data pertaining to the reference signature of a pathological microbiome is found on a first database and data pertaining to the signature of a microbiome of the healthy subject is found on a second database.
According to further features in the described preferred embodiments, the first database comprises data pertaining to a plurality of reference signatures of a pathological microbiome.
According to further features in the described preferred embodiments, the microbiome is selected from the group consisting of a gut microbiome, an oral microbiome, a bronchial microbiome, a skin microbiome and a vaginal microbiome.
According to further features in the described preferred embodiments, the method further comprises processing the sample prior to the determining.
According to further features in the described preferred embodiments, the processing comprises generating a nucleic acid sample.
According to further features in the described preferred embodiments, the method further comprises administering the artificial sweetener to the subject prior to the analyzing.
According to further features in the described preferred embodiments, the agent comprises a substance.
According to further features in the described preferred embodiments, the agent comprises a condition.
According to further features in the described preferred embodiments, the condition comprises circadian misalignment.
According to further features in the described preferred embodiments, the pathological microbiome is processed.
According to further features in the described preferred embodiments, the pathological microbiome is non-processed.
According to further features in the described preferred embodiments, the kit further comprises a non-pathological microbiome.
According to further features in the described preferred embodiments, the at least one microbiome component is at least one gene of a microbe of the microbiome.
According to further features in the described preferred embodiments, the at least one microbiome component is at least one microbe of the microbiome.
According to further features in the described preferred embodiments, the kit further comprises:
(ii) a second agent which is capable of determining an amount of a second microbiome component, wherein the level of the second microbiome component is significantly different in an agent-tolerant microbiome and an agent-intolerant microbiome.
According to an aspect of some embodiments of the present invention there is provided a method of providing an antibiotic or probiotic treatment for a subject in need thereof comprising:
(a) analyzing the circadian rhythm of the microbiome of the subject;
(b) providing the antibiotic or probiotic treatment to the subject wherein the dose or time of administration of the antibiotic or probiotic treatment is selected based on said circadian rhythm of the microbiome of the subject.
According to further features in the described preferred embodiments, step (a) is effected by analyzing the microbial signature of said microbiome.
According to further features in the described preferred embodiments, step (a) is effected by analyzing metabolites of the microbiome.
According to further features in the described preferred embodiments, providing the antibiotic is effected at a time wherein the bacteria targeted by the antibiotic is at a trough of the circadian rhythm.
According to further features in the described preferred embodiments, providing the probiotic is effected at a time when the bacteria of the probiotic is at a peak of the circadian rhythm.
Unless otherwise defined, all technical and/or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the invention, exemplary methods and/or materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting.
Implementation of the method and/or apparatus of embodiments of the invention can involve performing or completing selected tasks manually, automatically, or a combination thereof. Moreover, according to actual instrumentation and equipment of embodiments of the method and/or apparatus of the invention, several selected tasks could be implemented by hardware, by software or by firmware or by a combination thereof using an operating system.
For example, hardware for performing selected tasks according to embodiments of the invention could be implemented as a chip or a circuit. As software, selected tasks according to embodiments of the invention could be implemented as a plurality of software instructions being executed by a computer using any suitable operating system. In an exemplary embodiment of the invention, one or more tasks according to exemplary embodiments of method and/or apparatus as described herein are performed by a data processor, such as a computing platform for executing a plurality of instructions. Optionally, the data processor includes a volatile memory for storing instructions and/or data and/or a non-volatile storage, for example, a magnetic hard-disk and/or removable media, for storing instructions and/or data. Optionally, a network connection is provided as well. A display and/or a user input device such as a keyboard or mouse are optionally provided as well.
The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.
Some embodiments of the invention are herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of embodiments of the invention. In this regard, the description taken with the drawings makes apparent to those skilled in the art how embodiments of the invention may be practiced.
In the drawings:
(A) Schematic showing sampling times of microbiota over the course of two light-dark cycles.
(B) OTUs showing diurnal oscillations. OTUs with p<1 are shown and fluctuation amplitudes are indicated. Dashed line indicates p<0.05, JTK_cycle; n=10 individual mice at each Zeitgeber time (ZT).
(C) Taxonomic composition of fecal microbiota over the course of 48 hours.
(D) Histogram representation of bacterial genera oscillating with p<0.05, JTK_cycle.
(E, F) Representative examples of diurnal oscillations in the abundance of microbiota members; n=10 mice at each ZT.
(G, H) Histogram showing the distribution of standard deviation in gene occurrence of flagellar genes (G) and glycosaminoglycan (GAG) degradation genes versus other genes, normalized to the number of reads mapped to each gene.
(I) KEGG pathways showing diurnal oscillations. Only pathways with gene coverage >0.2 and p<1 are shown. Dashed line indicates p<0.05, JTK_cycle; n=2 individual mice at each ZT.
(J) Representative examples of anti-phasic diurnal oscillations in the abundance of functional KEGG pathways; n=2 individual mice at each ZT.
(K) Histogram representation of the 16 most significantly oscillating KEGG pathways, as identified by JTK_cycle.
The results shown are representative of four experiments (1A-F) or two experiments (1G-K).
(A) Schematic showing sampling times of microbiota every four hours over the course of four light-dark cycles.
(B) OTUs showing diurnal oscillations. Only OTUs with p<1 are shown. Dashed line indicates p<0.05, JTK_cycle; n=8 individual mice at each Zeitgeber time (ZT).
(C-D) Representative examples of diurnal oscillations in the abundance of microbiota members; n=8 mice at each ZT.
(E-G) Representative example of diurnal oscillations in the abundance of functional KEGG pathways; n=2 individual mice at each ZT.
(H) Pathway depiction of genes involved in flagellar assembly, bacterial chemotyxis, and type III secretion. Colors indicate differential abundance of genes at different ZTs.
(A) OTUs showing diurnal oscillations in wild-type and Per1/2-deficient mice. Only OTUs with p<1 are shown. Dashed line indicates p<0.05, JTK_cycle; n=10 individual mice in each group at each Zeitgeber time (ZT).
(B) Representative example of diurnal oscillations in wild-type mice, which are absent in Per1/2-deficient mice; n=10 mice at each ZT.
(C) Histogram representation of bacterial genera oscillating with p<0.05, JTK_cycle, in wild-type mice compared to Per1/2-deficient mice; n=10 mice at each ZT.
(D) Histogram representation of diurnal fluctuations of KEGG pathways in microbiota from wild-type mice, which are absent in microbiota from Per1/2-deficient mice; metagenomics analysis was performed in a total of three mice at each ZT and only pathways with a coverage >0.2 were compared.
(E) KEGG pathways showing diurnal oscillations in wild-type compared to Per1/2-deficient mice. Only pathways with gene coverage >0.2 and p<1 are shown. Dashed line indicates p<0.05, JTK_cycle.
(F-H) Diurnal variations in genes belonging to the indicated functional pathways in wild-type and Per1/2-deficient mice. Metagenomics analysis was performed in a total of three mice at each ZT.
The results shown are representative of two experiments.
(A-C) Diurnal variations in genes belonging to the indicated functional pathways in wild-type and Per1/2-deficient mice. Metagenomics analysis was performed in a total of three mice at each ZT.
(D, E) Alpha- (D) and beta-diversity (E) of fecal microbiota from wild-type and Per1/2-deficient mice. Samples per genotype are from different times of the day; n=90 in each group.
(F) Differential abundance of OTUs between fecal microbiota from wild-type and Per1/2-deficient mice; n=90 samples.
(G, H) Alpha- (G) and beta-diversity (H) of fecal microbiota from wild-type and ASC-deficient mice.
(I) OTUs showing diurnal oscillations in ASC-deficient mice. Only OTUs with p<1 are shown. Dashed line indicates p<0.05, JTK_cycle; n=8 individual mice at each ZT.
(J) Representative example of diurnal oscillations in the microbiota of ASC-deficient mice; n=8 individual mice at each ZT.
(K, L) Diurnal feeding pattern in wild-type (K) and Per1/2-deficient mice (L). Mice were fed ad libitum and followed over three dark-light cycles. Examples shown are representative of 8 individual mice.
(A) Schematic showing timed feeding protocol.
(B) OTUs showing diurnal oscillations in wild-type mice on different feeding schedules. Only OTUs with p<1 are shown. Dashed line indicates p<0.05, JTK_cycle; n=10 individual mice at each ZT.
(C-F) Representative examples of phase shift in bacterial oscillations between dark phase-fed and light-phase fed wild-type mice; n=10 mice at each ZT.
(G) OTUs showing diurnal oscillations in Per1/2-deficient mice on different feeding schedules. Only OTUs with p<1 are shown. Dashed line indicates p<0.05, JTK_cycle; n=10 individual mice at each ZT.
(H-I) Representative examples of phase shift in bacterial oscillations between dark phase-fed and light-phase fed Per1/2-deficient mice; n=10 mice at each ZT.
(J) Quantification of oscillating OTUs with p<0.05, JTK_cycle, in wild-type and Per1/2-deficient mice on different feeding schedules.
(K) Schematic showing fecal transplantation of microbiota from Per1/2-deficient mice (arrhythmic microbiota) into germ-free recipients (gain of rhythmicity).
(L) OTUs showing diurnal oscillations in microbiota from Per1/2-deficient mice before and after transplantation into germ-free mice. Only OTUs with p<1 are shown. Dashed line indicates p<0.05, JTK_cycle; n=10 individual mice at each ZT in each group.
The results are representative of two independent experiments.
(A, B) Feeding times in dark phase-fed (A), and light phase-fed (B) mice. Graphs shown are representative of four individual mice measured.
(C) Colonic expression of Per2 in dark phase-fed or light phase-fed mice during the dark phase and light phase shows reprogramming of the intestinal clock by feeding rhythms; n=10 mice in each group. ** p<0.01, *** p<0.001.
(D, E) Histogram representation of bacterial genera oscillating with p<0.05, JTK_cycle, in wild-type mice (D) and Per1/2-deficient mice (E) fed during the dark phase or light phase only; n=10 mice at each ZT. Phase shifts in cycling OTUs are highlighted.
(F-H) Physical activity (F, H) and VCO2 over the course of three dark-light cycles in germ-free mice transplanted with microbiota from Per1/2-deficient mice (F, G) or from wild-type mice (H). Measurements were taken one week after transplantation. The graph is representative of eight individual mice measured.
(A) Schematic showing induction of jet lag by constant time shifting by 8 hours. Every three days, mice were subjected to a forward or backward shift of 8 hours. Controls remained under constant light-dark cycle conditions.
(B) Food intake of control and jet lag mice during the dark phase, light phase, and combined.** p<0.01, n.s. not significant.
(C) Heatmap representation of bacterial genera oscillating with p<0.05, JTK_cycle, in control mice compared to jet lagged mice; n=5 mice at each time point.
(D) OTUs showing diurnal oscillations in control and jet lag mice. Dashed line indicates p<0.05, JTK_cycle; n=5 individual mice at each time point.
(E) Representative example of bacterial oscillations in wild-type mice which are lost under jet lag; n=5 mice at each time point.
(F) Beta-diversity of gut microbial communities in control and jet lag mice after four weeks of time shifts. Samples are pooled from different times of the day.
(G) Beta-diversity of gut microbial communities in control and jet lag mice after four months of time shifts.
(H) Heatmap representation of changes in microbial composition induced by jet lag.
(A, B) Physical activity over the course of three dark-light cycles in control and jet lag mice. Rhythmic activity of a control mouse (A) is converted into a random pattern by induction of jet lag (B). The results shown are representative of 16 individual mice measured.
(C) Diurnal variations in food intake of control and jet lag mice over the course of a dark-light cycle. The results shown are representative of 16 individual mice measured.
(D-F) Rhythmic expression patterns of Bmal (D), Rev-erbα (E) and RORγt (F) in the colon is altered upon jet lag induction; n=4-5 mice at each ZT.
(A-E) Mice underwent time shift-induced jet lag and were fed a high fat diet. Half of the mice were treated with antibiotics; n=10 mice in each group.
(A) Weight gain over 9 weeks of high-fat feeding. ** p<0.01, *** p<0.001.
(B) Oral glucose tolerance test performed 8 weeks after initiation of jet lag. * p<0.05, ** p<0.01.
(C) Fasting glucose levels of control and jet lag mice, with or without Abx treatment, after 8 weeks of jet lag. * p<0.05.
(D, E) Fat (D) and lean (E) body mass of control and jet lag mice, with or without Abx treatment, after 8 weeks of jet lag. ** p<0.01.
(F) Weight and fat content of control and jet lag mice after 4 months of time shifts in the jet lag group. * p<0.05.
(G-I) Microbiota from control or jet lag mice was transplanted into germ-free (GF) mice; n=4-6 mice in each group.
(G) Weight gain over 4 weeks. * p<0.05
(H) Oral glucose tolerance test performed on day 3 post fecal transfer. * p<0.05 (I) Fat and lean body mass in recipient mice one month post fecal transfer. ** p<0.01
(J) T2-weighted MR images of control and jet lag mice after 8 weeks of jet lag. Above, coronal images; below, axial images.
(K) T2-weighted MR images of recipient mice one month post fecal transfer. Above, coronal images; below, axial images.
The results shown are representative of three (9A-E) and two (9G-I) independent experiments.
(A-D) Physical activity over the course of 2.5 dark-light cycles in control (A, B) and jet lag mice (C, D) fed a high-fat diet. (B) and (D) are additionally treated with antibiotics. The results shown are representative of 32 individual mice measured.
(E, F) Diurnal variations in food intake of control and jet lag mice over the course of a dark-light cycle. All mice were fed a high-fat diet. In (F), mice were treated with antibiotics.
(G) OTUs showing diurnal oscillations in wild-type mice after one week on high-fat diet. Only OTUs with p<1 are shown. Dashed line indicates p<0.05, JTK_cycle; n=10 individual mice at each Zeitgeber time (ZT).
(H, I) Representative examples of diurnal oscillations in the abundance of microbiota members in mice on high-fat diet; n=10 mice at each ZT.
(J) OTUs showing diurnal oscillations in wild-type mice after one week of antibiotic treatment. Only OTUs with p<1 are shown. Dashed line indicates p<0.05, JTK_cycle; n=10 individual mice at each Zeitgeber time (ZT).
(K, L) Representative example of diurnal oscillations in the abundance of microbiota members in mice on antibiotics; n=10 mice at each ZT.
(A) Schematic showing sampling times of human microbiota from two subjects over the course of multiple light-dark cycles.
(B, C) OTUs showing diurnal oscillations in two human subjects. Only OTUs with p<1 are shown. Dashed line indicates p<0.05, JTK_cycle.
(D) Histogram representation of bacterial genera from one human subject oscillating with p<0.05, JTK_cycle.
(E) Representative example of diurnal bacterial oscillations over five consecutive days.
(F) KEGG pathways showing diurnal oscillations. Only pathways with gene coverage >0.2 and p<1 are shown. Dashed line indicates p<0.05, JTK_cycle.
(G, H) Examples of anti-phasic abundance peaks in KEGG pathways from human microbiota. ZT data are pooled from five consecutive days.
(I) Histogram representation of oscillations in KEGG pathways.
(A, B) Representative examples of diurnal fluctuations in the relative abundance of members of the commensal microbiota from one human subject over the course of five consecutive days.
(C) Oscillations in taxonomic composition of human fecal microbiota over the course of five days.
(D) Representative examples of diurnal fluctuations in functional pathways from human microbiota over the course of five consecutive days.
(A) Schematic showing times of microbiota sampling from subjects before, during, and after jet lag induced by an 8-10-hour time shift.
(B) Phylum level composition of microbiota from two human subjects corresponding to the sampling times shown in (A).
(C) Schematic of fecal transplantation from human subjects before, during, and after jet lag into germ-free mice.
(D) Weight gain of recipient mice over three weeks; n=5 mice in each group. ** p<0.01
(E) Oral glucose tolerance test of recipient mice performed on day 3 post fecal transfer; n=5 mice in each group. * p<0.05
(F) T2-weighted MR images of recipient mice performed three weeks after fecal transfer. Above, coronal images; below, axial images.
The results shown are representative of 2 independent experiments (C-F).
(A) Schematic showing “hallmark” taxonomic units and functional pathways with preferential abundance at certain times during a 24-hours light-dark cycle.
(B) Schematic depicting diurnal microbiota pathway activity in nocturnal wild-type mice, loss of oscillations in clock-disrupted mice, and phase-reversed fluctuations in humans.
(A) Schematic showing sampling times for microbiota epithelial attachment, metabolome, metagenome, and colonic transcriptome. (B) Diurnal fluctuations in the number of bacteria attached to colonic epithelium over two dark-light cycles as determined by bacterial qPCR of adherent communities. (C) SEM images showing diurnal fluctuations in epithelial colonization by bacteria. Images are representative of 10 randomly chosen views per mouse. (D) Beta-diversity of mucosal-adherent bacteria over the course of two light-dark cycles. (E) Relative taxonomic composition of mucosal-adherent bacteria over the course of two light-dark cycles. (F) Heatmap representation of the most significantly oscillating mucosal-adherent operational taxonomic units (OTUs), p<0.05 and q<0.2, JTK_cycle. (G) Epithelial-adherent OTUs showing diurnal oscillations in relative abundance. Fluctuation amplitudes are depicted. Dashed line indicates p<0.05, JTK_cycle. (H, I) Examples of bacterial species showing fluctuating relative abundance in mucosal-adherent communities.
Data are representative of two independent experiments with N=45 mice.
(A) Total number of luminal bacteria of the large intestine over the course of two days. (B, C) Quantification (B) and representative SEM images (C) showing diurnal fluctuations in epithelial colonization by bacteria over the course of a day. Quantification was done on 10 randomly selected images per mouse.
Data are representative of two independent experiments with N=45 mice.
(A, B) Diurnal rhythmicity of beta-diversity of mucosal-adherent bacteria, as shown by principal coordinate analysis of samples obtained from two consecutive dark-light phases. (C) UniFrac distance of the initial time point compared to all other time points over the course of two light-dark cycles. (D) Total number of different mucosal-adherent bacterial classes over a course of two days. (E) Epithelial-adherent OTUs showing diurnal oscillations in total numbers. Fluctuation amplitudes are depicted. Dashed line indicates p<0.05, JTK_cycle. (F-I) Examples of mucosal-adherent bacterial species undergoing rhythmic fluctuations in total numbers over the course of two days. Data are representative of two independent experiments with N=45 mice.
(A, C, E) Metabolites of the indicated chemical groups showing diurnal oscillations in fecal matter. Fluctuation amplitudes are depicted. Dashed line indicates p<0.05, JTK_cycle. (B, F, D) Examples for rhythmicity in intestinal metabolites belonging to different chemical groups. (G, H) Examples for rhythmicity in two microbial genes, bioD and bioB, which are involved in biotin synthesis. Data are representative of 1-2 independent experiments with N=18-27 samples in each group.
(A, B) Representative SEM images (A) and quantification (B) of diurnal fluctuations in epithelial colonization by bacteria over the course of a day in antibiotics-treated and control mice (C) Relative taxonomic composition of mucosal-adherent bacteria over the course of two light-dark cycles after antibiotic treatment. (D) Principal coordinate analysis of mucosal-adherent communities in antibiotics-treated mice every 6 hours over the course of one day. (E) UniFrac distance of the initial time point compared to all other time points over the course of two light-dark cycles in antibiotics-treated mice. Data are representative of two independent experiments with N=36 mice.
(A) Colonic transcripts showing diurnal oscillations in antibiotics-treated mice and controls. Fluctuation amplitudes are depicted. Dashed line indicates p<0.05, JTK_cycle. (B-D) Representative examples of colonic transcripts with shared rhythmicity between antibiotics-treated mice and controls (B), loss of rhythmicity upon antibiotic treatment (C), and de-novo rhythmicity in antibiotics-treated mice (D).
(E) Schematic representation of peak metabolic activities in the colon of antibiotics-treated mice compared to controls. Each oscillating transcript was assigned an acrophase ZTs, and peak profiles were determined by KEGG analysis for each ZT. Note that peak metabolic activities differ between both groups. (F) Colonic transcripts showing diurnal oscillations in germ-free mice and controls. Fluctuation amplitudes are depicted. Dashed line indicates p<0.05, JTK_cycle. (G-I) Heatmap representation of shared cycling transcripts between germ-free mice and controls (G), of transcripts uniquely cycling in control mice (H), and of transcripts uniquely oscillating in germ-free mice (I), p<0.05, JTK_cycle. Data are representative of 1-2 experiments with N=27-45 mice in each group.
(A-C) Distribution of food intake over the course of three dark-light phases in mice fed ad libitum (A), fed only during the dark phase (B), or only during the light phase (C). (D) Example of bacterial genes showing a phase shift upon light phase feeding. (E, F) Heatmap representation of oscillating metagenomic KEGG modules (E) and pathways (F) showing a phase shift upon reversal of feeding times. (F) Heatmap representation of oscillating metagenomic KEGG pathways showing a phase shift upon reversal of feeding times. (G) Example of phase shift in a metagenomic module related to bacterial mucus degradation upon light phase feeding of mice. (H) Heatmap representation of selected KEGG modules and pathways involved in bacterial motility showing a phase shift upon reversal of feeding times. (I, J) Examples of phase reversal of oscillating transcripts in dark phase-fed versus light phase-fed mice. Data are representative of 1-2 independent experiments with N=18-27 samples in each group.
(J) Heatmap representation of shared cycling transcripts between dark phase-fed versus light phase-fed mice. Note the phase shift between oscillations in both groups.
(K, L) Examples of phase reversal of oscillating transcripts in dark phase-fed versus light phase-fed mice. Data are representative of two independent experiments with N=18-27 samples in each group.
N=18-27 samples in each group.
(A) Hepatic transcripts showing diurnal oscillations in antibiotics-treated mice and controls. Fluctuation amplitudes are depicted. Dashed line indicates p<0.05, JTK_cycle. (B) KEGG pathway analysis of hepatic cycling transcripts shared between antibiotics-treated mice and controls. (C-F) Examples of hepatic transcript oscillations shared between antibiotics-treated mice and controls. (G) Example of hepatic transcript oscillations unique to control mice. (H) Schematic of suggested model for interaction of genetic and environmental factor in determining transcriptome oscillations. The network of transcription factors constituting the molecular clock integrates signals coming from diet and the microbiota, which determine rhythmic activation of target genes. This, in turn, determines the portion of the transcriptome that undergoes cyclic oscillations. N=45 samples in each group.
The present invention, in some embodiments thereof, relates to the microbiome and, more particularly, but not exclusively, to a method and apparatus for predicting a response of a subject to one or more agents by analysis of the microbiome.
Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not necessarily limited in its application to the details set forth in the following description or exemplified by the Examples. The invention is capable of other embodiments or of being practiced or carried out in various ways.
The gut microbiome is in constant flux, continuously changing its microbial composition in response to external stimuli such as food intake, antibiotic intake and disease. As such, the phylogenetic compositions of microbiomes vary from one individual to another. Such differences have been associated with diseases such as colon cancer and inflammatory bowel disease, susceptibility to obesity, the severity of autism spectrum disorders, and differences in responses to medical treatments.
The present inventors have now found that the level of toxicity of an agent or a condition to a particular person can be measured by analyzing its affect on his microbiome. More specifically, an agent which is toxic to a particular individual will drive the composition of his microbiome to be more similar to a pathological microbiome (e.g. a microbiome from a diseased subject), whereas a non-toxic agent will not have this effect. Thus, his microbiome can be used as a barometer to gauge the toxicity of external stimuli.
Whilst reducing the present invention to practice, the present inventors have demonstrated that consumption of commonly used artificial sweetener formulations drives the development of glucose intolerance in particular subjects, through induction of compositional and functional alterations to the intestinal microbiota. Whilst some subjects seem to be more tolerant to the effects of artificial sweeteners, others are less tolerant. The individual response to artificial sweeteners was shown to be due to differences in the microbiome of the tested subjects.
In addition, the present inventors have found that the bacterial content of the gut microbiome is vulnerable to the ravages of circadian rhythm alterations. Disruption to the circadian rhythm caused the microbial content of the gut microbiome to be more similar to a microbiome of an obese or glucose intolerant subject. Thus, when jet-lagged microbes were transferred from either mice or humans into germ-free mice, the rodents became more susceptible to glucose intolerance and diabetes.
Whilst further reducing the present invention to practice, the present inventors showed that the gut microbiome has its own innate circadian rhythm which impacts the daily local and systemic transcriptome oscillations of the host. This diurnal meta-organismal activity is adapted to food intake, whose timing determines the phase of microbiome activity and synchronization with the host. The present inventors showed that microbiota disruption by antibiotic treatment or in germ-free mice reprograms the intestinal and hepatic host transcriptome to feature both massive loss and de-novo genesis of oscillations, resulting in temporal reorganization of metabolic pathways.
Accordingly, the present inventors propose that the natural circadian rhythm of the microbiome of the host should be taken into account (i.e. care should be taken so as to not disrupt the circadian rhythm of the microbiome) when determining antibiotic or probiotic treatment regimens.
Thus, according to one aspect of the present invention there is provided a method of determining an effect of an agent on a microbiome of a subject comprising:
(a) exposing the microbiome to the agent;
(b) comparing the signature of the microbiome following the exposing with reference signature of a pathological microbiome, wherein when the signature of the microbiome is statistically significantly similar to the pathological microbiome reference signature, it is indicative that the agent has a deleterious effect on the microbiome.
As used herein, the term “microbiome” refers to the totality of microbes (bacteria, fungae, protists), their genetic elements (genomes) in a defined environment.
The microbiome may be a gut microbiome, an oral microbiome, a bronchial microbiome, a skin microbiome or a vaginal microbiome.
According to a particular embodiment, the microbiome is a gut microbiome (i.e. intestinal microbiome).
The present embodiments encompass the recognition that microbial signatures can be relied upon as proxy for microbiome composition and/or activity. Microbial signatures comprise data points that are indicators of microbiome composition and/or activity. Thus, according to the present invention, changes in microbiomes can be detected and/or analyzed through detection of one or more features of microbial signatures.
In some embodiments, a microbial signature includes information relating to absolute amount of one or more types of microbes, and/or products thereof. In some embodiments, a microbial signature includes information relating to relative amounts of five, ten, twenty or more types of microbes and/or products thereof.
Examples of microbial products include, but are not limited to mRNAs, polypeptides, carbohydrates and metabolites.
In some embodiments, a microbial signature includes information relating to presence, level, and/or activity of at least ten types of microbes. In some embodiments, a microbial signature includes information relating to presence, level, and/or activity of between 5 and 100 types of microbes. In some embodiments, a microbial signature includes information relating to presence, level, and/or activity of between 100 and 1000 or more types of microbes. In some embodiments, a microbial signature includes information relating to presence, level, and/or activity of substantially all types of bacteria within the microbiome. In some embodiments, a microbial signature includes information relating to presence, level, and/or activity of substantially all types of microbes within the microbiome.
In some embodiments, a microbial signature includes information relating to presence, level, and/or activity of metabolites of at least ten types of microbes. In some embodiments, a microbial signature includes information relating to presence, level, and/or activity of metabolites of between 5 and 100 types of microbes. In some embodiments, a microbial signature includes information relating to presence, level, and/or activity of metabolites of between 100 and 1000 or more types of microbes. In some embodiments, a microbial signature includes information relating to presence, level, and/or activity of substantially metabolites of all types of bacteria within the microbiome. In some embodiments, a microbial signature includes information relating to presence, level, and/or activity of metabolites of substantially all types of microbes within the microbiome.
According to this aspect of the present invention the microbiome signature includes a presence or level of at least one, at least 10, at least 20, at least 50, at least 100, at least 200, at least 300, at least 400, at least 500, at least 600, at least 700, at least 800, at least 900, at least 1000, at least 1200, at least 1500 or all the species of microbes of the microbiome.
In some embodiments, a microbiome signature comprises a level or set of levels of at least one, or at least five, or at least ten or more types of microbes (e.g. bacteria) or components or by-products thereof. In some embodiments, a microbial signature comprises a level or set of levels of at least one or at least five or at least ten or more DNA sequences. In some embodiments, a microbial signature comprises a level or set of levels of ten or more 16S rRNA gene sequences. In some embodiments, a microbial signature comprises a level or set of levels of 18S rRNA gene sequences. In some embodiments, a microbial signature comprises a level or set of levels of at least five or at least ten or more RNA transcripts. In some embodiments, a microbial signature comprises a level or set of levels of at least five or at least ten or more proteins. In some embodiments, a microbial signature comprises a level or set of levels of at least one or at least five or at least ten or more metabolites.
16S and 18S rRNA gene sequences encode small subunit components of prokaryotic and eukaryotic ribosomes respectively. rRNA genes are particularly useful in distinguishing between types of microbes because, although sequences of these genes differs between microbial species, the genes have highly conserved regions for primer binding. This specificity between conserved primer binding regions allows the rRNA genes of many different types of microbes to be amplified with a single set of primers and then to be distinguished by amplified sequences.
According to one embodiment, the subject under analysis is a healthy subject (i.e. one who has not been diagnosed with a disease known to affect the microbiome). Thus, according to one embodiment, the subject under analysis does not have a metabolic disease (e.g. is not diabetic or prediabetic, does not have Crohn's disease) or cancer. The subjects are typically mammals (e.g. humans).
According to one embodiment, the microbiome profile of the subject under analysis is included in a subject specific database, and the profile of the reference microbiome (pathological microbiome) derived from a non-healthy subject is included in a second database. The second database may comprise profiles of more than one pathological microbiome and may comprise average data from a plurality of pathological microbiomes.
Both the subject-specific database and the second database may be stored in a computer readable format on a computer readable medium, and is optionally and preferably accessed by a data processor, such as a general purpose computer or dedicated circuitry.
The subject-specific database may comprise additional data describing the subject. Representative examples of types of data other than the microbiome profile or signature include without limitation responses to foods, blood chemistry of the subject, partial blood chemistry of the subject, genetic profile of the subject, metabolomic data associated with the subject, the medical condition of the subject, sleep patterns of the subject, food intake habits of the subject (e.g. does the subject use artificial sweeteners or not), and the like. The subject-specific database may also comprise data pertaining to the frequency of intake or exposure to the agent, the time of intake or exposure to the agent etc. These and other types of data are described in more detail below.
In order to analyze the microbiome, samples are taken from a subject. Thus, for example stool samples may be taken to analyze the gut microbiome, bronchial samples may be taken to analyze the bronchial microbiome etc. According to a particular embodiment, the microbiome of a subject is determined from a stool sample of the subject. It will be appreciated that microbiomes of the same source are compared (i.e. the gut microbiome of the subject is compared with the gut microbiome of a second subject or group of subjects).
The present inventors have shown that changes in eating patterns (e.g. due to circadian misalignment) affect the composition of the microbiome. Therefore, preferably samples are taken at a fixed time in the day.
Agents which are analyzed according to this aspect of the present invention may be substances or conditions.
Substances which may be analyzed are typically non-caloric substances (i.e. have less than 3 calories per 100 g).
Exemplary non-caloric substances include food additives.
The food additive may be classified according to the European Union with an E number. Thus, for example a substance having an E number between 100-199 is a color, a substance having an E number between 200-299 is a preservative, a substance having an E number between 300-399 is an antioxidant, a substance having an E number between 400-499 is a thickener, stabilizer or emulsifier, a substance having an E number between 500-599 is a acidity regulator or anti-caking agent, a substance having an E number between 600-199 is a flavor enhancer, a substance having an E number between 700-799 is an antibiotic, a substance having an E number between 900-999 is a glazing agent or sweetener. Additional chemicals have E numbers between 1000-1599.
Food additives may be categorized into the following groups: Acids, Acidity regulators, Anticaking agents, Antifoaming agents, Antioxidants, Bulking agents, Colorings, Emulsifiers, Flavors, Flavor enhancers, Glazing agents, Humectants, Preservatives, stabilizers, artificial sweeteners and thickeners.
According to a particular embodiment, the substance is caffeine.
According to another embodiment, the substance is an artificial sweetener.
Examples of artificial sweeteners include, but are not limited to aspartame, acesulfame, steviol, saccharin, cyclamate, erythritol, isomalt, maltitol, lactitol, mannitol, Neohesperidine dihydrochalcone, Neotame, sorbitol, xylitol, and Sucralose.
According to another embodiment, the substance is a therapeutic agent.
Examples of therapeutic agents include, but are not limited to, inorganic or organic compounds; small molecules (i.e., less than 1000 Daltons) or large molecules (i.e., above 1000 Daltons); biomolecules (e.g. proteinaceous molecules, including, but not limited to, peptide, polypeptide, post-translationally modified protein, antibodies etc.) or a nucleic acid molecule (e.g. double-stranded DNA, single-stranded DNA, double-stranded RNA, single-stranded RNA, or triple helix nucleic acid molecules) or chemicals. Therapeutic agents may be natural products derived from any known organism (including, but not limited to, animals, plants, bacteria, fungi, protista, or viruses) or from a library of synthetic molecules. Therapeutic agents can be monomeric as well as polymeric compounds.
According to a particular embodiment, the substance is a metabolite.
As used herein, a “metabolite” is an intermediate or product of metabolism. The term metabolite is generally restricted to small molecules and does not include polymeric compounds such as DNA or proteins. A metabolite may serve as a substrate for an enzyme of a metabolic pathway, an intermediate of such a pathway or the product obtained by the metabolic pathway.
In preferred embodiments, metabolites include but are not limited to sugars, organic acids, amino acids, fatty acids, hormones, vitamins, oligopeptides (less than about 100 amino acids in length), as well as ionic fragments thereof. Cells can also be lysed in order to measure cellular products present within the cell. In particular, said metabolites are less than about 3000 Daltons in molecular weight, and more particularly from about 50 to about 3000 Daltons.
The metabolite of this aspect of the present invention may be a primary metabolite (i.e. essential to the microbe for growth) or a secondary metabolite (one that does not play a role in growth, development or reproduction, and is formed during the end or near the stationary phase of growth.
Representative examples of metabolic pathways in which the metabolites of the present invention are involved include, without limitation, citric acid cycle, respiratory chain, photosynthesis, photorespiration, glycolysis, gluconeogenesis, hexose monophosphate pathway, oxidative pentose phosphate pathway, production and β-oxidation of fatty acids, urea cycle, amino acid biosynthesis pathways, protein degradation pathways such as proteasomal degradation, amino acid degrading pathways, biosynthesis or degradation of: lipids, polyketides (including, e.g., flavonoids and isoflavonoids), isoprenoids (including, e.g., terpenes, sterols, steroids, carotenoids, xanthophylls), carbohydrates, phenylpropanoids and derivatives, alkaloids, benzenoids, indoles, indole-sulfur compounds, porphyrines, anthocyans, hormones, vitamins, cofactors such as prosthetic groups or electron carriers, lignin, glucosinolates, purines, pyrimidines, nucleosides, nucleotides and related molecules such as tRNAs, microRNAs (miRNA) or mRNAs.
According to a particular embodiment, the therapeutic agent is not a food or food additive.
According to another embodiment, the therapeutic agent is not for treating obesity or a disease related to glucose intolerance (e.g. diabetes).
According to still another embodiment, the substance is not a therapeutic agent.
The substances may be isolated or may be incorporated in a carrier such as a food or drink.
According to one embodiment, the carrier is a non-caloric carrier such as a non-caloric food or drink. Thus for example, the substance may be a diet drink or coffee without milk.
Preferably the microbiome is exposed to a similar amount of agent to which the subject under examination is routinely subjected to.
As mentioned, the agent which is tested may also be a condition.
Exemplary conditions contemplated by the present invention include but are not limited to altered sleep patterns, tobacco smoke exposure, radiation exposure, light exposure and food intake patterns.
The first step according to this aspect of the present invention involves exposing the microbiome to the agent. It will be appreciated that when the agent is a substance, this step may be affected in vivo or ex vivo. When the agent is a condition, this step is typically effected in vivo. The exposing may be a direct exposure (e.g. contacting) or may be effected via the subject (e.g. the subject is exposed to different sleep patterns).
The contacting may be carried out a single time, or may be affected on a multitude of occasions over the course of a particular time period.
It will be appreciated that the signature may be determined in a microbiome of a subject who has known to have been subjected to the agent or condition. This information may be obtained directly from the subject under analysis (e.g. using a questionnaire). Preferably, the subject has been subjected to the agent over a period of time (for example a week, a month or longer). According to a particular embodiment, the subject has been subjected to the agent at least once a day, at least two times a day, at least three times a day or more. Preferably, the subject has been subjected to the agent at least 1 month prior to the analysis, at least one week prior to the analysis and optionally at least one day prior to the analysis.
Following the contacting the signature of the microbiome of the test subject is compared with a reference signature of a pathological microbiome.
As used herein, the phrase “pathological microbiome” refers to a microbiome derived from a subject who is known to have a disease (e.g. metabolic disease such as diabetes, or pre-diabetes, cancer) or has already been preclassified as having a microbiome that is intolerant to the agent.
Quantifying Microbial Levels: In methods in accordance with the present invention, a microbial signature is obtained and/or determined by quantifying microbial levels. Methods of quantifying levels of microbes of various types are described herein below.
In some embodiments, determining a level or set of levels of one or more types of microbes or components or products thereof comprises determining a level or set of levels of one or more DNA sequences. In some embodiments, one or more DNA sequences comprises any DNA sequence that can be used to differentiate between different microbial types. In certain embodiments, one or more DNA sequences comprises 16S rRNA gene sequences. In certain embodiments, one or more DNA sequences comprises 18S rRNA gene sequences. In some embodiments, 1, 2, 3, 4, 5, 10, 15, 20, 25, 50, 100, 1,000, 5,000 or more sequences are amplified.
In some embodiments, a microbiota sample (e.g. fecal sample) is directly assayed for a level or set of levels of one or more DNA sequences. In some embodiments, DNA is isolated from a microbiota sample and isolated DNA is assayed for a level or set of levels of one or more DNA sequences. Methods of isolating microbial DNA are well known in the art. Examples include but are not limited to phenol-chloroform extraction and a wide variety of commercially available kits, including QIAamp DNA Stool Mini Kit (Qiagen, Valencia, Calif.).
In some embodiments, a level or set of levels of one or more DNA sequences is determined by amplifying DNA sequences using PCR (e.g., standard PCR, semi-quantitative, or quantitative PCR). In some embodiments, a level or set of levels of one or more DNA sequences is determined by amplifying DNA sequences using quantitative PCR. These and other basic DNA amplification procedures are well known to practitioners in the art and are described in Ausebel et al. (Ausubel F M, Brent R, Kingston R E, Moore D D, Seidman J G, Smith J A, Struhl K (eds). 1998. Current Protocols in Molecular Biology. Wiley: New York).
In some embodiments, DNA sequences are amplified using primers specific for one or more sequence that differentiate(s) individual microbial types from other, different microbial types. In some embodiments, 16S rRNA gene sequences or fragments thereof are amplified using primers specific for 16S rRNA gene sequences. In some embodiments, 18S DNA sequences are amplified using primers specific for 18S DNA sequences.
In some embodiments, a level or set of levels of one or more 16S rRNA gene sequences is determined using phylochip technology. Use of phylochips is well known in the art and is described in Hazen et al. (“Deep-sea oil plume enriches indigenous oil-degrading bacteria.” Science, 330, 204-208, 2010), the entirety of which is incorporated by reference. Briefly, 16S rRNA genes sequences are amplified and labeled from DNA extracted from a microbiota sample. Amplified DNA is then hybridized to an array containing probes for microbial 16S rRNA genes. Level of binding to each probe is then quantified providing a sample level of microbial type corresponding to 16S rRNA gene sequence probed. In some embodiments, phylochip analysis is performed by a commercial vendor. Examples include but are not limited to Second Genome Inc. (San Francisco, Calif.).
In some embodiments, determining a level or set of levels of one or more types of microbes or components or products thereof comprises determining a level or set of levels of one or more microbial RNA molecules (e.g., transcripts). Methods of quantifying levels of RNA transcripts are well known in the art and include but are not limited to northern analysis, semi-quantitative reverse transcriptase PCR, quantitative reverse transcriptase PCR, and microarray analysis.
In some embodiments, determining a level or set of levels of one or more types of microbes or components or products thereof comprises determining a level or set of levels of one or more microbial polypeptides. Methods of quantifying polypeptide levels are well known in the art and include but are not limited to Western analysis and mass spectrometry. These and all other basic polypeptide detection procedures are described in Ausebel et al.
In some embodiments, determining a level or set of levels of one or more types of microbes or components or products thereof comprises determining a level or set of levels of one or more microbial metabolites. In some embodiments, levels of metabolites are determined by mass spectrometry. In some embodiments, levels of metabolites are determined by nuclear magnetic resonance spectroscopy. In some embodiments, levels of metabolites are determined by enzyme-linked immunosorbent assay (ELISA). In some embodiments, levels of metabolites are determined by colorimetry. In some embodiments, levels of metabolites are determined by spectrophotometry.
Methods of analyzing SCFAs are known in the art. An exemplary method is described in the Examples section herein below.
It will be appreciated that the pathological microbiome reference signature is selected so as to correspond with the microbiome signature of the subject. For example, if the microbiome signature of the subject comprises amounts of microbe metabolites, then the pathological microbiome reference signature also comprises amounts of microbe metabolites. If the microbiome signature of the subject comprises expression data for a group of genes involved in glycosaminoglycan synthesis, then the pathological microbiome reference signature also comprises expression data for the group of genes involved in glycosaminoglycan synthesis.
According to one embodiment of this aspect of the present invention two microbiome signatures can be have a statistically significant similar signature when they comprise at least 50% of the same microbes, at least 60% of the same microbes, at least 70% of the same microbes, at least 80% of the same microbes, at least 90% of the same microbes, at least 91% of the same microbes, at least 92% of the same microbes, at least 93% of the same microbes, at least 94% of the same microbes, at least 95% of the same microbes, at least 96% of the same microbes, at least 97% of the same microbes, at least 98% of the same microbes, at least 99% of the same microbes or 100% of the same microbes.
Additionally, or alternatively, microbiomes may have a statistically significant similar signature when the quantity (e.g. occurrence) in the microbiome of at least one microbe of interest is identical. According to another embodiment, microbiomes may have a statistically significant similar signature when the relative ratio in the microbiome of at least 10% of its microbes are identical. According to another embodiment, microbiomes may have a statistically significant similar signature when the relative ratio in the microbiome of at least 20% of its microbes are identical.
According to another embodiment, microbiomes may have a statistically significant similar signature when the relative ratio in the microbiome of at least 30% of its microbes are identical. According to another embodiment, microbiomes may have a statistically significant similar signature when the relative ratio in the microbiome of at least 40% of its microbes are identical. According to another embodiment, microbiomes may have a statistically significant similar signature when the relative ratio in the microbiome of at least 50% of its microbes are identical.
According to another embodiment, microbiomes may have a statistically significant similar signature when the relative ratio in the microbiome of at least 60% of its microbes are identical. According to another embodiment, microbiomes may have a statistically significant similar signature when the relative ratio in the microbiome of at least 70% of its microbes are identical. According to another embodiment, microbiomes may have a statistically significant similar signature when the relative ratio in the microbiome of at least 80% of its microbes are identical.
According to another embodiment, microbiomes may have a statistically significant similar signature when the relative ratio in the microbiome of at least 90% of its microbes are identical. Thus, the fractional percentage of microbes (e.g. relative amount, ratio, distribution, frequency, percentage, etc.) of the total may be statistically similar.
According to another embodiment, in order to classify a microbe as belonging to a particular genus, family, order, class or phylum, it must comprise at least 90% sequence homology, at least 91% sequence homology, at least 92% sequence homology, at least 93% sequence homology, at least 94% sequence homology, at least 95% sequence homology, at least 96% sequence homology, at least 97% sequence homology, at least 98% sequence homology, at least 99% sequence homology to a reference microbe known to belong to the particular genus. According to a particular embodiment, the sequence homology is at least 95%.
According to another embodiment, in order to classify a microbe as belonging to a particular species, it must comprise at least 90% sequence homology, at least 91% sequence homology, at least 92% sequence homology, at least 93% sequence homology, at least 94% sequence homology, at least 95% sequence homology, at least 96% sequence homology, at least 97% sequence homology, at least 98% sequence homology, at least 99% sequence homology to a reference microbe known to belong to the particular species. According to a particular embodiment, the sequence homology is at least 97%.
In determining whether a nucleic acid or protein is substantially homologous or shares a certain percentage of sequence identity with a sequence of the invention, sequence similarity may be defined by conventional algorithms, which typically allow introduction of a small number of gaps in order to achieve the best fit. In particular, “percent identity” of two polypeptides or two nucleic acid sequences is determined using the algorithm of Karlin and Altschul (Proc. Natl. Acad. Sci. USA 87:2264-2268, 1993). Such an algorithm is incorporated into the BLASTN and BLASTX programs of Altschul et al. (J. Mol. Biol. 215:403-410, 1990). BLAST nucleotide searches may be performed with the BLASTN program to obtain nucleotide sequences homologous to a nucleic acid molecule of the invention. Equally, BLAST protein searches may be performed with the BLASTX program to obtain amino acid sequences that are homologous to a polypeptide of the invention. To obtain gapped alignments for comparison purposes, Gapped BLAST is utilized as described in Altschul et al. (Nucleic Acids Res. 25:3389-3402, 1997). When utilizing BLAST and Gapped BLAST programs, the default parameters of the respective programs (e.g., BLASTX and BLASTN) are employed. See www(dot)ncbi(dot)nlm(dot)nih(dot)gov for more details.
According to still another embodiment, two microbiome signatures can be classified as being similar, if the relative number of genes belonging to a particular pathway is similar. Such pathways are described herein below.
According to still another embodiment, two microbiome signatures can be classified as being similar, if the relative amount of a product generated by the microbes is similar. Such products are described herein below.
As well as comparing the microbiome signature of the subject under analysis to the pathological reference microbiome, the microbiome signature of the subject may also (or alternatively) be compared to a non-pathological reference microbiome.
Thus, according to another embodiment, the method further comprises comparing the signature of the microbiome following the exposing with a non-pathological microbiome reference signature, wherein when the signature of the microbiome is statistically significantly different to the non-pathological microbiome reference signature, it is indicative that the agent has a deleterious effect on the microbiome. Additionally, when the signature of the microbiome is statistically significantly similar to the non-pathological microbiome reference signature, it is indicative that the agent has a non-deleterious effect on the microbiome.
Non-pathological microbiomes are typically derived from healthy subjects (i.e. do not have any diseases, especially metabolic diseases). Further, the non-pathological microbiomes are typically derived from healthy subjects that do not chronically ingest agents which are known to adversely affect the microbiome. Thus, for example, the non-pathological microbiome is typically derived from a healthy subject that does not chronically ingest artificial sweeteners.
Further steps may be added to any of the methods described herein which are used to assess an agent's effect on the microbiome including for example administering to the subject the agent prior to the analyzing of the microbiome signature and/or preparing the sample for analysis (e.g. removal of fecal matter, making a protein extract, preparing a nucleic acid sample etc.).
Any of the analytical methods described herein can be embodied in many forms. For example, it can be embodied in on a tangible medium such as a computer for performing the method operations. It can be embodied on a computer readable medium, comprising computer readable instructions for carrying out the method operations. It can also be embodied in electronic device having digital computer capabilities arranged to run the computer program on the tangible medium or execute the instruction on a computer readable medium.
Computer programs implementing the analytical method of the present embodiments can commonly be distributed to users on a distribution medium such as, but not limited to, CD-ROMs or flash memory media. From the distribution medium, the computer programs can be copied to a hard disk or a similar intermediate storage medium. In some embodiments of the present invention, computer programs implementing the method of the present embodiments can be distributed to users by allowing the user to download the programs from a remote location, via a communication network, e.g., the internet. The computer programs can be run by loading the computer instructions either from their distribution medium or their intermediate storage medium into the execution memory of the computer, configuring the computer to act in accordance with the method of this invention. All these operations are well-known to those skilled in the art of computer systems.
By carrying out the methods described herein, it is possible to determine the tolerance of a subject to the agent. It then becomes possible to provide recommendations as to the amount of a substance which can be tolerated (e.g. ingested), or the amount or level of a condition that can be tolerated by a subject.
Following are two examples of agents that were shown to have an effect on the microbiome.
Artificial Sweeteners: The present inventors have demonstrated that consumption of commonly used artificial sweetener formulations drives the development of glucose intolerance in particular subjects, through induction of compositional and functional alterations to the intestinal microbiota. Whilst some subjects seem to be more tolerant to the effects of artificial sweeteners, others are less tolerant. The individual response to artificial sweeteners was shown to be due to differences in the microbiome of the tested subjects.
The phrase “tolerance to artificial sweeteners” as used herein refers to the ability to ingest (either eat or drink) the FDA's maximal acceptable daily intake (ADI) of artificial sweetener (e.g. commercial saccharin 5 mgkg−1) without showing a clinical parameter that is associated with disturbed glucose metabolism. Thus, for example a person may be considered tolerant to an artificial sweetener if he does not fail a glucose tolerance test. For example, a person may be considered as failing a glucose tolerance test if 2 hours following ingestion of 75 grams of glucose, his blood glucose level is less than 140 mg/dl, and all values between 0 and 2 hours are less than 200 mg/dl. Additionally, a person may be considered tolerant to an artificial sweetener if his fasting glucose levels are within the normal range.
Typically, the subjects who are tested for their tolerance to artificial sweeteners are not diabetic or pre-diabetic. Preferably they do not suffer from a metabolic disorder.
Particularly relevant microbiome signatures when testing for tolerance to artificial sweeteners include: level of microbes belonging to the order bacteroidales, Clostridilales, Bactobacillales, YS2, RF32, Erysipelotrichales, Burkholderiales, Lactobacillales, Anaeroplasmatales, Enterobacteriales and/or Campylobacterales.
According to a particular embodiment, the microbiome signature comprises a level of microbes belonging to the order bacteroidales, Clostridilales, Bactobacillales, YS2, RF32, Erysipelotrichales, Burkholderiales and/or Campylobacterales, when testing for tolerance to artificial sweeteners.
According to another embodiment, the microbiome signature comprises a level of microbes belonging to the phylum Bacteroidetes, Firmicutes and/or Tenericutes, when testing for tolerance to artificial sweeteners.
According to another embodiment, the microbiome signature comprises a level of microbes belonging to the class Bacteroidia, Bacilli, Clostridia, Mollicutes and/or Gammaproteobacteria, when testing for tolerance to artificial sweeteners.
According to another embodiment, the microbiome signature comprises a level of microbes belonging to the order Bacteroidales, Lactobacillales, Clostridiales, Anaeroplasmatales and/or Enterobacteriales, when testing for tolerance to artificial sweeteners.
According to another embodiment, the microbiome signature comprises a level of microbes belonging to the family Bacteroidaceae, Lactobacillaceae, Porphyromonadaceae, Anaeroplasmataceae, Clostridiaceae, Odoribacteraceae, Ruminococcaceae, Streptococcaceae, Dehalobacteriaceae, Enterobacteriaceae and/or S24-7, when testing for tolerance to artificial sweeteners.
According to another embodiment, the microbiome signature comprises a level of microbes belonging to the genus, Bacteroides, Lactobacillus, Parabacteroides, Anaeroplasma, Candidatus Arthromitus, Odoribacter, Lactococcus and/or Dehalobacterium, when testing for tolerance to artificial sweeteners.
According to yet another embodiment, the microbiome signature comprises a level of microbes of at least one of the species set forth in Table 5 herein below, when testing for tolerance to artificial sweeteners.
As mentioned herein above, the microbiome signature may refer to the level of particular genes expressed in the microbes of the microbiome.
More specifically, the microbiome signature may comprise levels of genes belonging to the glycan degradation pathway (e.g. the glycosaminoglycan pathway), when testing for tolerance to artificial sweeteners.
According to still another embodiment, the microbiome signature may comprise levels of microbe genes including for example genes involved in starch and sucrose metabolism, genes involved in fructose and mannose metabolism, genes involved in folate biosynthesis, genes involved in glycerolipid-biosynthesis, genes involved in fatty acid biosynthesis, genes involved in glucose transport pathways, genes involved in ascorbate and aldarate metabolism, genes involved in lipopolysaccharide biosynthesis and/or genes involved in bacterial chemotaxis, when testing for tolerance to artificial sweeteners.
As mentioned herein above, the microbiome signature may refer to the level of a product or bi-product generated by microbes of the microbiome—for example a metabolite.
An exemplary metabolite which may be analyzed in the sample are short chain fatty acids (SCFAs), when testing for tolerance to artificial sweeteners.
According to one embodiment of this aspect of the present invention two microbiome signatures can be classified as being similar if the relative level of microbes belonging to the order bacteroidales, Clostridilales, Bactobacillales, YS2, RF32, Erysipelotrichales, Burkholderiales, Lactobacillales, Anaeroplasmatales, Enterobacteriales and/or Campylobacterales is statistically similar.
According to one embodiment of this aspect of the present invention two microbiome signatures can be classified as being similar if the relative level of microbes belonging to the order bacteroidales, Clostridilales, Bactobacillales, YS2, RF32, Erysipelotrichales, Burkholderiales and/or Campylobacterales is statistically similar.
According to one embodiment of this aspect of the present invention two microbiome signatures can be classified as being similar if the relative level of microbes belonging to the phylum Bacteroidetes, Firmicutes and/or Tenericutes is statistically similar.
According to one embodiment of this aspect of the present invention two microbiome signatures can be classified as being similar if the relative level of microbes belonging to the class Bacteroidia, Bacilli, Clostridia, Mollicutes and/or Gammaproteobacteria is statistically similar.
According to one embodiment of this aspect of the present invention two microbiome signatures can be classified as being similar if the relative level of microbes belonging to the order Bacteroidales, Lactobacillales, Clostridiales, Anaeroplasmatales and/or Enterobacteriales is statistically similar.
According to one embodiment of this aspect of the present invention two microbiome signatures can be classified as being similar if the relative level of microbes belonging to the family Bacteroidaceae, Lactobacillaceae, Porphyromonadaceae, Anaeroplasmataceae, Clostridiaceae, Odoribacteraceae, Ruminococcaceae, Streptococcaceae, Dehalobacteriaceae, Enterobacteriaceae and/or S24-7 is statistically similar.
According to one embodiment of this aspect of the present invention two microbiome signatures can be classified as being similar if the relative level of microbes belonging to the genus, Bacteroides, Lactobacillus, Parabacteroides, Anaeroplasma, Candidatus Arthromitus, Odoribacter, Lactococcus and/or Dehalobacterium is statistically similar.
According to one embodiment of this aspect of the present invention two microbiome signatures can be classified as being similar if the relative level of microbes belonging to the species set forth in Table 5 herein below is statistically similar.
According to another aspect of the present invention there is provided a method of determining tolerance to an artificial sweetener in a subject comprising analyzing the amount of microbes belonging to an order selected from the group consisting of bacteroidales order, Clostridilales order, Bactobacillales order, YS2 order, RF32 order, Erysipelotrichales order, Burkholderiales order and/or Campylobacterales order in a microbiome of the subject, wherein an amount of microbes of the Bacteroidales, Clostridilales, Bactobacillales and/or YS2 order above a predetermined level is indicative of a subject being tolerant to the artificial sweetener and an amount of microbes of the RF32, Erysipelotrichales, Burkholderiales and/or Campylobacterales order above a predetermined level is indicative of a subject being intolerant to the artificial sweetener.
Determining the amount of microbes belonging to a particular order has been described herein above.
According to this aspect the relative amount of microbes belonging to at least one of the orders, two of the orders, three of the orders, four of the orders, five of the orders, six of the orders, seven of the orders, eight of the orders, nine of the orders, ten of the orders, eleven of the orders or all of the above mentioned orders are analyzed.
Preferably the increase in the level is at least 1.5 fold, 2 fold, 5 fold or greater.
According to yet another aspect of the present invention there is provided a method of determining tolerance to an artificial sweetener in a subject comprising analyzing the amount of at least one microbe or class of microbes as set forth in Table 5 in a microbiome of the subject, wherein the amount of at least one of the microbes or the class of microbes above a predetermined level is indicative of a subject being intolerant to the artificial sweetener.
According to this aspect of the present invention at least one of the microbes described in Table 4 is analyzed, at least 5% of the microbes described in Table 4 are analyzed, at least 10% of the microbes described in Table 4 are analyzed, at least 20% of the microbes described in Table 4 are analyzed, at least 30% of the microbes described in Table 4 are analyzed, at least 40% of the microbes described in Table 4 are analyzed, at least 50% of the microbes described in Table 4 are analyzed.
Preferably the increase in the level is at least 1.5 fold, 2 fold, 5 fold or greater.
Further steps may be added to any of the methods described herein which are used to assess a subject's tolerance to an artificial sweetener including for example administering to the subject the artificial sweetener prior to the analyzing of the microbiome signature and preparing the sample for analysis (e.g. removal of fecal matter, making a protein extract, preparing a nucleic acid sample etc.).
Altered Circadian Rhythm
The present inventors have shown that subjects with circadian misalignment (e.g. those suffering from jet-lag) have microbiomes that are statistically significantly similar to pathological microbiomes and suggest that the resulting microbial community may contribute to metabolic imbalances.
Thus, the present inventors propose determining if a subject is tolerant to having his circadian rhythm altered (e.g. changing time zones, performing night shifts etc.) by analyzing his microbiome. If his microbiome is statistically significantly similar to a pathological microbiome then it is indicative that he is intolerant to these conditions.
The present invention contemplates kits for analyzing a person's microbiome in order to determine his tolerance to different agents or conditions.
Thus, according to another aspect of the present invention there is provided a kit for determining whether a subject is tolerant to an agent comprising:
(i) an agent which is capable of determining an amount of at least one microbiome component, wherein the level of the at least one microbiome component is significantly different in an agent-tolerant microbiome and an agent-intolerant microbiome; and
(ii) a pathological microbiome.
In one embodiment, the kit comprises an agent which is capable of determining an amount of at least one microbiome component, wherein the level of the at least one microbiome component is significantly different in an artificial sweetener-tolerant and artificial sweetener-intolerant subject.
The microbiome component (e.g. biomolecule) may be enriched, depleted, up-regulated, down-regulated, degraded, or stabilized in the agent-tolerant microbiome as compared to the agent-intolerant microbiome.
As mentioned herein above the microbiome component (i.e. biomolecule) may be a nucleic acid, an oligonucleic acid, an amino acid, a peptide, a polypeptide, a protein, a lipid, a carbohydrate, a metabolite, or a fragment thereof. Nucleic acids may include RNA, DNA, and naturally occurring or synthetically created derivatives. The microbiome related component may be present in, produced by, or modified by a microorganism within the gut.
The biomolecule may allow for the analysis of a particular species or class of microbes.
In the case of a microbe, the agent may be a primer or set of primers for amplifying 16S rRNA or 18S rRNA. An example of such a primer set is provided in the Examples section herein below. The kit of this embodiment may comprise additional reagents required for subsequent sequencing reactions.
In the case of a gene (DNA) or RNA, the agent may be an oligonucleotide which hybridizes specifically to the DNA or RNA of interest.
The oligonucleotide may be in the form of an amplification primer. In this case, the kit may comprise additional components to perform an amplification reaction such as enzymes, salts and buffers. Typically, the kit comprises oligonucleotides for amplifying at least two genes known to be differentially expressed in artificial sweetener tolerant/intolerant microbiomes. According to a particular embodiment, the two genes are part of a pathway known to be involved in artificial sweetener tolerance—such as the glycan degradation pathway (e.g. the glycosaminoglycan pathway).
Additionally, or alternatively, the primers may amplify genes involved in at least one process or pathway known to be up-regulated or down-regulated in an agent-tolerant microbiome as compared to an agent-intolerant microbiome. Thus, in the case of artificial sweeteners, the primer may amplify genes in one or more of the following processes or pathways: starch and sucrose metabolism, fructose and mannose metabolism, folate biosynthesis, glycerolipid-biosynthesis, fatty acid biosynthesis glucose transport pathways, ascorbate and aldarate metabolism, lipopolysaccharide biosynthesis and/or bacterial chemotaxis.
Alternatively, the oligonucleotide may be attached to a solid surface (i.e. array). Several substrates suitable for the construction of arrays are known in the art, and one skilled in the art will appreciate that other substrates may become available as the art progresses. The substrate may be a material that may be modified to contain discrete individual sites appropriate for the attachment or association of the oligonucleotide and is amenable to at least one detection method. Non-limiting examples of substrate materials include glass, modified or functionalized glass, plastics (including acrylics, polystyrene and copolymers of styrene and other materials, polypropylene, polyethylene, polybutylene, polyurethanes, TeflonJ, etc.), nylon or nitrocellulose, polysaccharides, nylon, resins, silica or silica-based materials including silicon and modified silicon, carbon, metals, inorganic glasses and plastics. In an exemplary embodiment, the substrates may allow optical detection without appreciably fluorescing.
A substrate may be planar, a substrate may be a well, i.e. a 364 well plate, or alternatively, a substrate may be a bead. Additionally, the substrate may be the inner surface of a tube for flow-through sample analysis to minimize sample volume.
Similarly, the substrate may be flexible, such as a flexible foam, including closed cell foams made of particular plastics.
The oligonucleotide or oligonucleotides may be attached to the substrate in a wide variety of ways, as will be appreciated by those in the art. The oligonucleotide may either be synthesized first, with subsequent attachment to the substrate, or may be directly synthesized on the substrate. The substrate and the oligonucleotide may be derivatized with chemical functional groups for subsequent attachment of the two. For example, the substrate may be derivatized with a chemical functional group including, but not limited to, amino groups, carboxyl groups, oxo groups or thiol groups. Using these functional groups, the oligonucleotide may be attached using functional groups on the oligonucleotide either directly or indirectly using linkers.
The oligonucleotide may also be attached to the substrate non-covalently. For example, a biotinylated oligonucleotide can be prepared, which may bind to surfaces covalently coated with streptavidin, resulting in attachment. Alternatively, an oligonucleotide or oligonucleotides may be synthesized on the surface using techniques such as photopolymerization and photolithography. Additional methods of attaching oligonucleotides to arrays and methods of synthesizing oligonucleotides on substrates are well known in the art, i.e. VLSIPS technology from Affymetrix (e.g., see U.S. Pat. No. 6,566,495, and Rockett and Dix, “DNA arrays: technology, options and toxicological applications,” Xenobiotica 30(2):155-177, all of which are hereby incorporated by reference in their entirety).
In one embodiment, the oligonucleotide or oligonucleotides attached to the substrate are located at a spatially defined address of the array. Arrays may comprise from about 1 to about several hundred thousand addresses or more. In one embodiment, the array may be comprised of less than 10,000 addresses. In another alternative embodiment, the array may be comprised of at least 10,000 addresses. In yet another alternative embodiment, the array may be comprised of less than 5,000 addresses. In still another alternative embodiment, the array may be comprised of at least 5,000 addresses. In a further embodiment, the array may be comprised of less than 500 addresses. In yet a further embodiment, the array may be comprised of at least 500 addresses.
An oligonucleotide may be represented more than once on a given array. In other words, more than one address of an array may be comprised of the same oligonucleotide. In some embodiments, two, three, or more than three addresses of the array may be comprised of the same oligonucleotide. In certain embodiments, the array may comprise control oligonucleotides and/or control addresses. The controls may be internal controls, positive controls, negative controls, or background controls.
The array may be comprised of oligonucleotides which hybridize with DNA or RNA which are indicative of an artificial sweetener tolerant or non-tolerant microbiome.
In one embodiment, the array may comprise an agent which can quantify or qualify the presence of a biomolecule enriched in the agent tolerant host microbiome compared to the agent intolerant host microbiome. In another embodiment, the array may comprise an agent which can quantify or qualify the presence of a biomolecule depleted in the agent tolerant host microbiome compared to the agent intolerant host microbiome. In yet another embodiment, the array may comprise an agent which can quantify or qualify the presence of a biomolecule up-regulated in the agent tolerant host microbiome compared to the agent intolerant host microbiome. In still another embodiment, the array may comprise an agent which can quantify or qualify the presence a biomolecule down-regulated in the agent tolerant host microbiome compared to the agent intolerant host microbiome. In still yet another embodiment, the array may comprise an agent which can quantify or qualify the presence of a biomolecule degraded in the agent tolerant host microbiome compared to the agent intolerant host microbiome. In an alternative embodiment, the array may comprise an agent which can quantify or qualify the presence of a biomolecule stabilized in the agent tolerant host microbiome compared to the agent intolerant host microbiome.
For example, when the agent is an artificial sweetener, the array may comprise oligonucleotides that hybridize with DNA/RNA sequences that encode polypeptides involved in the glycan degradation pathway (e.g. the glycosaminoglycan pathway).
Additionally, or alternatively, when the agent is an artificial sweetener, the array may comprise oligonucleotides that hybridize with DNA/RNA sequences that encode polypeptides involved in at least one more of the following processes or pathways: starch and sucrose metabolism, fructose and mannose metabolism, folate biosynthesis, glycerolipid-biosynthesis, fatty acid biosynthesis glucose transport pathways, ascorbate and aldarate metabolism, lipopolysaccharide biosynthesis and/or bacterial chemotaxis.
Preferably, at least 2, 5, 10, 15, 20 genes of a particular pathway are represented on the array.
In one embodiment, the array comprises oligonucleotides that hybridize with at least 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210, 215, 220, 225, 230, 235, 240, 245, 250, 255, 260, 275, 280, 285, 290, 295, 300, 305, 310, 315, 320, 325, 330, 335, 340, 345, 350, 355, 360, 365, 370, 375, 380, 385, 390, 395, or 400 oligonucleotides indicative of, or modulated in, agent tolerant host microbiome compared to an agent-intolerant host microbiome. In another embodiment, the array comprises oligonucleotides that specifically identify at least 200, at least 300, at least 400, at least 500, at least 600, at least 700, at least 800, or at least 900 biomolecules indicative of, or modulated in, an agent-tolerant host microbiome compared to an agent-intolerant host microbiome.
The kits described herein may also comprise control samples. According to one embodiment, the kit comprises a positive control e.g. a pathological microbiome.
Additionally, or alternatively, the kit comprises a negative control e.g. a non pathological microbiome.
The pathological and/or non-pathological microbiome may be processed. Thus, the control microbiomes may be represented as isolated polynucleotides or proteins.
Alternatively, the control microbiome may be represented by microbes.
The control samples may be in any suitable form, for example in a powdered dry form. In addition, the control samples may have undergone processing in order for it to increase its survival. For example, the microorganism may be coated or encapsulated in a polysaccharide, fat, starch, protein or in a sugar matrix. Standard encapsulation techniques known in the art can be used. For example, techniques discussed in U.S. Pat. No. 6,190,591, which is hereby incorporated by reference in its entirety, may be used.
According to still another aspect of the present invention there is provided a method of restoring the tolerance of a subject to an agent comprising administering to the subject an effective amount of a probiotic composition which comprises statistically significantly similar microbes to the non-pathological microbiome, thereby restoring the subjects tolerance to the agent.
For example, the present invention contemplates microbial compositions (e.g. probiotic compositions), wherein a majority of the microbes of the composition are microbes of the bacteroidales order, the Clostridilales order, the Bactobacillales order and/or the YS2 order for increasing tolerance to artificial sweeteners.
The present invention further contemplates microbial compositions (e.g. probiotic or antibiotic compositions) for increasing tolerance to circadian misalignment.
For example, the present inventors have shown that microbiota samples obtained during jet lag showed a higher relative representation of Firmicutes, which was reversed upon recovery from jet lag. Thus agents which can reduce the level of Firmicutes in the microbiome may be effective at restoring a subject's tolerance to circadian misalignment.
As used herein, the term “probiotic” refers to any microbial type that is associated with health benefits in a host organism and/or reduction of risk and/or symptoms of a disease, disorder, condition, or event in a host organism. In some embodiments, probiotics are formulated in a food product, functional food or nutraceutical. In some embodiments, probiotics are types of bacteria.
The microbial compositions of this aspect of the present invention may be statistically significantly similar to a microbiome of a subject who has found to be tolerant of the agent.
The microbial compositions may be taken from a microbiota sample of the microbiome.
A microbiota sample comprises a sample of microbes and or components or products thereof from a microbiome.
In some embodiments, a microbiota sample is collected by any means that allows recovery of the microbes and without disturbing the relative amounts of microbes or components or products thereof of a microbiome. The particular method of recovery should be adapted to the microbiome source.
Alternatively, the microbial composition may be artificially created by adding known amounts of different microbes.
It will be appreciated that the microbial composition which is derived from the microbiota sample of a subject may be manipulated prior to administrating by increasing the amount of a particular strain or depleting the amount of a particular strain. Alternatively, the microbial compositions are treated in such a way so as not to alter the relative balance between the microbial species and taxa comprised therein. In some embodiments, the microbial composition is expanded ex vivo using known culturing methods prior to administration. In other embodiments, the microbial composition is not expanded ex vivo prior to administration.
According to one embodiment, the microbial composition is not derived from fecal material.
According to still another embodiment, the microbial composition is devoid (or comprises only trace quantities) of fecal material (e.g., fiber).
The probiotic microorganism may be in any suitable form, for example in a powdered dry form. In addition, the probiotic microorganism may have undergone processing in order for it to increase its survival. For example, the microorganism may be coated or encapsulated in a polysaccharide, fat, starch, protein or in a sugar matrix. Standard encapsulation techniques known in the art can be used. For example, techniques discussed in U.S. Pat. No. 6,190,591, which is hereby incorporated by reference in its entirety, may be used.
According to a particular embodiment, the probiotic microorganism composition is formulated in a food product, functional food or nutraceutical.
In some embodiments, a food product, functional food or nutraceutical is or comprises a dairy product. In some embodiments, a dairy product is or comprises a yogurt product. In some embodiments, a dairy product is or comprises a milk product.
In some embodiments, a dairy product is or comprises a cheese product. In some embodiments, a food product, functional food or nutraceutical is or comprises a juice or other product derived from fruit. In some embodiments, a food product, functional food or nutraceutical is or comprises a product derived from vegetables. In some embodiments, a food product, functional food or nutraceutical is or comprises a grain product, including but not limited to cereal, crackers, bread, and/or oatmeal. In some embodiments, a food product, functional food or nutraceutical is or comprises a rice product. In some embodiments, a food product, functional food or nutraceutical is or comprises a meat product.
Prior to administration, the subject may be pretreated with an agent which reduces the number of naturally occurring microbes in the microbiome (e.g. by antibiotic treatment). According to a particular embodiment, the treatment significantly eliminates the naturally occurring gut microflora by at least 20%, 30% 40%, 50%, 60%, 70%, 80% or even 90%.
In some embodiments, administering comprises any means of administering an effective (e.g., therapeutically effective) or otherwise desirable amount of a composition to an individual. In some embodiments, administering a composition comprises administration by any route, including for example parenteral and non-parenteral routes of administration. Parenteral routes include, e.g., intraarterial, intracerebroventricular, intracranial, intramuscular, intraperitoneal, intrapleural, intraportal, intraspinal, intrathecal, intravenous, subcutaneous, or other routes of injection. Non-parenteral routes include, e.g., buccal, nasal, ocular, oral, pulmonary, rectal, transdermal, or vaginal. Administration may also be by continuous infusion, local administration, sustained release from implants (gels, membranes or the like), and/or intravenous injection.
In some embodiments, a composition is administered in an amount and/or according to a dosing regimen that is correlated with a particular desired outcome (e.g., with a particular change in microbiome composition and/or signature that correlates with an outcome of interest). In some embodiments, the desired outcome is enhanced tolerance to artificial sweeteners, as described above. In some embodiments, the desired outcome is tolerance to jet-lag or night shift work.
Particular doses or amounts to be administered in accordance with the present invention may vary, for example, depending on the nature and/or extent of the desired outcome, on particulars of route and/or timing of administration, and/or on one or more characteristics (e.g., weight, age, personal history, genetic characteristic, lifestyle parameter, severity of diabetes and/or level of risk of diabetes, etc., or combinations thereof). Such doses or amounts can be determined by those of ordinary skill. In some embodiments, an appropriate dose or amount is determined in accordance with standard clinical techniques. Alternatively or additionally, in some embodiments, an appropriate dose or amount is determined through use of one or more in vitro or in vivo assays to help identify desirable or optimal dosage ranges or amounts to be administered.
In some particular embodiments, appropriate doses or amounts to be administered may be extrapolated from dose-response curves derived from in vitro or animal model test systems. The effective dose or amount to be administered for a particular individual can be varied (e.g., increased or decreased) over time, depending on the needs of the individual. In some embodiments, where bacteria are administered, an appropriate dosage comprises at least about 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000 or more bacterial cells. In some embodiments, the present invention encompasses the recognition that greater benefit may be achieved by providing numbers of bacterial cells greater than about 1000 or more (e.g., than about 1500, 2000, 2500, 3000, 35000, 4000, 4500, 5000, 5500, 6000, 7000, 8000, 9000, 10,000, 15,000, 20,000, 25,000, 30,000, 40,000, 50,000, 75,000, 100,000, 200,000, 300,000, 400,000, 500,000, 600,000, 700,000, 800,000, 900,000, 1×106, 2×106, 3×106, 4×106, 5×106, 6×106, 7×106, 8×106, 9×106, 1×107, 1×108, 1×109, 1×101°, 1×1011, 1×1012, 1×1013 or more bacteria.
As well as treating a subject with probiotic compositions, the present invention also contemplates treating subjects with anti-microbial compositions whose presence are known to cause intolerance to an agent.
As used herein, the term “antibiotic agent” refers to a group of chemical substances, isolated from natural sources or derived from antibiotic agents isolated from natural sources, having a capacity to inhibit growth of, or to destroy bacteria, and other microorganisms, used chiefly in treatment of infectious diseases. Examples of antibiotic agents include, but are not limited to; Amikacin; Amoxicillin; Ampicillin; Azithromycin; Azlocillin; Aztreonam; Aztreonam; Carbenicillin; Cefaclor; Cefepime; Cefetamet; Cefinetazole; Cefixime; Cefonicid; Cefoperazone; Cefotaxime; Cefotetan; Cefoxitin; Cefpodoxime; Cefprozil; Cefsulodin; Ceftazidime; Ceftizoxime; Ceftriaxone; Cefuroxime; Cephalexin; Cephalothin; Cethromycin; Chloramphenicol; Cinoxacin; Ciprofloxacin; Clarithromycin; Clindamycin; Cloxacillin; Co-amoxiclavuanate; Dalbavancin; Daptomycin; Dicloxacillin; Doxycycline; Enoxacin; Erythromycin estolate; Erythromycin ethyl succinate; Erythromycin glucoheptonate; Erythromycin lactobionate; Erythromycin stearate; Erythromycin; Fidaxomicin; Fleroxacin; Gentamicin; Imipenem; Kanamycin; Lomefloxacin; Loracarbef; Methicillin; Metronidazole; Mezlocillin; Minocycline; Mupirocin; Nafcillin; Nalidixic acid; Netilmicin; Nitrofurantoin; Norfloxacin; Ofloxacin; Oxacillin; Penicillin G; Piperacillin; Retapamulin; Rifaxamin, Rifampin; Roxithromycin; Streptomycin; Sulfamethoxazole; Teicoplanin; Tetracycline; Ticarcillin; Tigecycline; Tobramycin; Trimethoprim; Vancomycin; combinations of Piperacillin and Tazobactam; and their various salts, acids, bases, and other derivatives. Anti-bacterial antibiotic agents include, but are not limited to, aminoglycosides, carbacephems, carbapenems, cephalosporins, cephamycins, fluoroquinolones, glycopeptides, lincosamides, macrolides, monobactams, penicillins, quinolones, sulfonamides, and tetracyclines.
Antibacterial agents also include antibacterial peptides. Examples include but are not limited to abaecin; andropin; apidaecins; bombinin; brevinins; buforin II; CAP18; cecropins; ceratotoxin; defensins; dermaseptin; dermcidin; drosomycin; esculentins; indolicidin; LL37; magainin; maximum H5; melittin; moricin; prophenin; protegrin; and or tachyplesins.
According to a particular embodiment, the antibiotic is a non-absorbable antibiotic.
Thus, for example, the present invention contemplates treating a subject with an antibiotic that reduces the microbes of the RF32, Erysipelotrichales, Burkholderiales and/or Campylobacterales order in order to enhance a subject's tolerance to an artificial sweetener. Preferably, the antibiotic does not have efficacy (or has less efficacy) against microbes which are of the Bacteroidales, Clostridilales, Bactobacillales and/or YS2 order.
The present inventors have found that the oscillating patterns of the microbiome impact the daily local and systemic transcriptome oscillations of the host. The present inventors showed that microbiota disruption by antibiotic treatment or in germ-free mice reprogrammed the intestinal and hepatic host transcriptome to feature both massive loss and de-novo genesis of oscillations, resulting in temporal reorganization of metabolic pathways. Accordingly, the present inventors propose that analysis of the rhythm of the microbiome over the course of a day may shed important information as to the dose or regime of administration of an antibiotic or probiotic agent. Thus, for example if the analysis of the rhythm of the microbiome shows that a particular microbe is at a peak in the morning hours and at a trough in the evening hours, then it may be recommended that a probiotic agent which comprises this microbe is administered in the morning and not the evening so as not to alter the natural circadian rhythm of the microbiome. If the analysis of the rhythm of the microbiome shows that a particular microbe is at a peak in the morning hours and at a trough in the evening hours, then it may be recommended that an antibiotic agent which downregulates this microbe is administered in the evening and not the morning so as not to alter the natural circadian rhythm of the microbiome.
Analysis of the microbiome may be performed by analyzing the level of microbes themselves or products (e.g. metabolites) thereof. Analysis of the microbiome is further described herein above.
In order to analyze the rhythm of the microbiome, at least two samples, at least 3 samples, at least 4 samples, at least 5 samples, at least 6 samples or more of the microbiome should be measured during the course of a 24 hour period.
It is to be understood that while the above types of additional information were described separately, the present embodiments contemplate any combination of two or more types of information for the databases.
As used herein the term “about” refers to ±10%.
The word “exemplary” is used herein to mean “serving as an example, instance or illustration.” Any embodiment described as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments and/or to exclude the incorporation of features from other embodiments.
The word “optionally” is used herein to mean “is provided in some embodiments and not provided in other embodiments.” Any particular embodiment of the invention may include a plurality of “optional” features unless such features conflict.
The terms “comprises”, “comprising”, “includes”, “including”, “having” and their conjugates mean “including but not limited to”.
The term “consisting of” means “including and limited to”.
The term “consisting essentially of” means that the composition, method or structure may include additional ingredients, steps and/or parts, but only if the additional ingredients, steps and/or parts do not materially alter the basic and novel characteristics of the claimed composition, method or structure.
As used herein, the singular form “a”, “an” and “the” include plural references unless the context clearly dictates otherwise. For example, the term “a compound” or “at least one compound” may include a plurality of compounds, including mixtures thereof.
Throughout this application, various embodiments of this invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.
Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range. The phrases “ranging/ranges between” a first indicate number and a second indicate number and “ranging/ranges from” a first indicate number “to” a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals therebetween.
It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.
Various embodiments and aspects of the present invention as delineated hereinabove and as claimed in the claims section below find experimental support in the following examples.
It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.
Various embodiments and aspects of the present invention as delineated hereinabove and as claimed in the claims section below find experimental support in the following examples.
Reference is now made to the following examples, which together with the above descriptions illustrate some embodiments of the invention in a non limiting fashion.
Generally, the nomenclature used herein and the laboratory procedures utilized in the present invention include molecular, biochemical, microbiological and recombinant DNA techniques. Such techniques are thoroughly explained in the literature. See, for example, “Molecular Cloning: A laboratory Manual” Sambrook et al., (1989); “Current Protocols in Molecular Biology” Volumes I-III Ausubel, R. M., ed. (1994); Ausubel et al., “Current Protocols in Molecular Biology”, John Wiley and Sons, Baltimore, Md. (1989); Perbal, “A Practical Guide to Molecular Cloning”, John Wiley & Sons, New York (1988); Watson et al., “Recombinant DNA”, Scientific American Books, New York; Birren et al. (eds) “Genome Analysis: A Laboratory Manual Series”, Vols. 1-4, Cold Spring Harbor Laboratory Press, New York (1998); methodologies as set forth in U.S. Pat. Nos. 4,666,828; 4,683,202; 4,801,531; 5,192,659 and 5,272,057; “Cell Biology: A Laboratory Handbook”, Volumes I-III Cellis, J. E., ed. (1994); “Culture of Animal Cells—A Manual of Basic Technique” by Freshney, Wiley-Liss, N.Y. (1994), Third Edition; “Current Protocols in Immunology” Volumes I-III Coligan J. E., ed. (1994); Stites et al. (eds), “Basic and Clinical Immunology” (8th Edition), Appleton & Lange, Norwalk, Conn. (1994); Mishell and Shiigi (eds), “Selected Methods in Cellular Immunology”, W. H. Freeman and Co., New York (1980); available immunoassays are extensively described in the patent and scientific literature, see, for example, U.S. Pat. Nos. 3,791,932; 3,839,153; 3,850,752; 3,850,578; 3,853,987; 3,867,517; 3,879,262; 3,901,654; 3,935,074; 3,984,533; 3,996,345; 4,034,074; 4,098,876; 4,879,219; 5,011,771 and 5,281,521; “Oligonucleotide Synthesis” Gait, M. J., ed. (1984); “Nucleic Acid Hybridization” Hames, B. D., and Higgins S. J., eds. (1985); “Transcription and Translation” Hames, B. D., and Higgins S. J., eds. (1984); “Animal Cell Culture” Freshney, R. I., ed. (1986); “Immobilized Cells and Enzymes” IRL Press, (1986); “A Practical Guide to Molecular Cloning” Perbal, B., (1984) and “Methods in Enzymology” Vol. 1-317, Academic Press; “PCR Protocols: A Guide To Methods And Applications”, Academic Press, San Diego, Calif. (1990); Marshak et al., “Strategies for Protein Purification and Characterization—A Laboratory Course Manual” CSHL Press (1996); all of which are incorporated by reference as if fully set forth herein. Other general references are provided throughout this document. The procedures therein are believed to be well known in the art and are provided for the convenience of the reader. All the information contained therein is incorporated herein by reference.
Mice—C57Bl/6 mice were purchased from Harlan and allowed to acclimatize to the local animal facility for two weeks before used for experimentation. Unless otherwise specified, mice were kept under strict light-dark cycles, with lights being turned on at 6 am and turned off at 6 pm. In all experiments, age- and gender-matched were used. Mice were 8-9 weeks of age at the beginning of experiments. For experiments involving high-fat diet, only male mice were used. For all other experiments, both male and female mice were used. Stool samples were collected fresh and on the basis of individual mice. Fresh pellets were collected in tubes, immediately frozen in liquid nitrogen upon collection, and stored at −80° C. until DNA isolation.
Unless stated otherwise, 10 mice per experimental group were used for the collection of fecal material from each individual mouse. For the induction of jet lag, mice were shifted between control light conditions (lights turned on at 6 am and turned off at 6 pm) and an 8-hour time difference (lights turned on at 10 μm and turned off at 10 am) every three days. Experiments performed on jet lagged mice were done when these mice were in the same light-dark cycle as control mice, and Zeitgeber times (ZTs) were synchronized (i.e. ZT0 of jet lag mice corresponded to ZT0 of control mice, as all mice were exposed to the same light-dark conditions at the onset of sample collection).
In food restriction experiments, mice were housed under standard light-dark conditions (6 am to 6 pm), but had access to food only during the light or dark phase, respectively, for two weeks. For antibiotic treatment, mice were given a combination of vancomycin (1 g/l), ampicillin (1 g/l), kanamycin (1 g/l), and metronidazole (1 g/l) in their drinking water (Rakoff-Nahoum et al., 2004). All antibiotics were obtained from Sigma Aldrich. Antibiotics were given for the entire duration of experiments, i.e. starting at the onset of jet lag induction until the experimental endpoint. For experiments involving gnotobiotic mice, germ-free Swiss Webster mice were housed in sterile isolators. For fecal transplantation experiments, 100 mg of stool was resuspended in 1 ml of PBS, homogenized, and filtered through a 70 μm strainer. Recipient mice were gavaged with 2000 of the filtrate. All experimental procedures were approved by the local IACUC.
Human samples—Stool collection from humans was performed using sterile cotton swabs and stored at room temperature until arrival at the laboratory, where DNA extraction was performed. Collection of human stool was approved by the Tel Aviv Sourasky Medical Center Institutional Review Board. In experiments involving human stool collection at multiple times of the day, subjects ate four meals per day, and fecal samples were collected after food intake.
Taxonomic microbiota analysis—Frozen fecal samples were processed for DNA isolation using the MoBio PowerSoil kit according to the manufacturer's instructions. 1 ng of the purified fecal DNA was used for PCR amplification and sequencing of the bacterial 16S rRNA gene. Amplicons spanning the variable region 2 (V2) of the 16S rRNA gene were generated by using the following barcoded primers: Fwd 5′-NNNNNNNNAGAGTTTGATCCTGGCTCAG-3′ (SEQ ID NO: 1), Rev 5′-TGCTGCCTCCCGTAGGAGT-3′ (SEQ ID NO: 2), where N represents a barcode base. The reactions were subsequently pooled in an equimolar ratio, purified (PCR clean kit, Promega), and used for Illumina MiSeq sequencing. 500 bp paired-end sequencing was employed. Reads were then processed using the QIIME (Quantitative Insights Into Microbial Ecology, www(dot)qiime(dot)org) analysis pipeline as described (Caporaso et al., 2010; Elinav et al., 2011). In brief, fasta quality files and a mapping file indicating the barcode sequence corresponding to each sample were used as inputs, reads were split by samples according to the barcode, taxonomical classification was performed using the RDP-classifier, a de-novo taxonomic tree of the sequences was built based on sequence similarity, and an OTU table was created. After chimera removal, the average number of reads per fecal sample was 34,847. Sequences sharing 97% nucleotide sequence identity in the V2 region were binned into operational taxonomic units (97% ID OTUs) using uclust, chimeric sequences were removed using ChimeraSlayer.
Metagenomic sequence mapping. Illumina sequencing reads were mapped to a gut microbial gene catalogue [20203603] using GEM mapper [23103880] with the following parameters:
Functional assignment. Reads mapped to the gut microbial gene catalogue were assigned a KEGG [10592173, 24214961] identification number, according to the gene to category mapping that accompanied each of these databases. Genes were subsequently mapped to KEGG modules and pathways. For the KEGG pathway analysis, only pathways whose gene coverage was above 0.2 were included. KEGG pathways were then tested by JTK_cycle to daily oscillations.
Glucose tolerance test—Mice were fasted for 6 hours and subsequently given 200 μl of a 0.2 g/ml glucose solution (JT Baker) by oral gavage. Blood glucose was determined at 0, 15, 30, 60, 90, and 120 minutes after glucose challenge (Contour™ blood glucose meter, Bayer, Switzerland).
Magnetic resonance imaging—Mice were anesthetized with isofluorane (5% for induction, 1-2% for maintenance) mixed with oxygen (1 liter/min) and delivered through a nasal mask. Once anesthetized, the animals were placed in a head-holder to assure reproducible positioning inside the magnet. Respiration rate was monitored and kept throughout the experimental period around 60-80 breaths per minute. MRI experiments were performed on 9.4 Tesla BioSpec Magnet 94/20 USR system (Bruker, Germany) equipped with gradient coils system capable of producing pulse gradient of up to 40 gauss/cm in each of the three directions. All MR images had been acquired with a quadrature resonator coil (Bruker). The MRI protocol included two sets of coronal and axial multi-slices T2-weighted MR images. The T2-weighted images acquired using the multi-slice RARE sequence (TR=2500 ms, TE=35 ms, RARE factor=8), and matrix size was 256×256, four averages, corresponding to an image acquisition time of 2 min 40 sec per set. The first set was used to acquire 21 axial slices with 1.00 mm slice thickness (no gap). The field of view was selected with 4.2×4.2 cm2. The second set was used to acquire 17 coronal slices with 1.00 mm slice thickness (no gap). The field of view was selected with 7.0×5.0 cm2.
Total fat and lean mass of mice were measured by EchoMRI-100™ (Echo Medical Systems, Houston, Tex.).
Metabolic studies—Food intake and locomotor activity were measured using the PhenoMaster system (TSE-Systems, Bad Homburg, Germany), which consists of a combination of sensitive feeding sensors for automated measurement and a photobeam-based activity monitoring system detects and records ambulatory movements, including rearing and climbing, in each cage. All parameters were measured continuously and simultaneously. Mice were trained singly-housed in identical cages prior to data acquisition.
Gene expression analysis—Tissues were preserved in RNAlater solution (Ambion) and subsequently homogenized in Trizol reagent (Invitrogen). Cells sorted by FACS were resuspended in Trizol reagent. RNA was purified according to the manufacturer's instructions. One microgram of total RNA was used to generate cDNA (HighCapacity cDNA Reverse Transcription kit; Applied Biosystems). RealTime-PCR was performed using gene-specific primer/probe sets (Applied Biosystems) and Kapa Probe Fast qPCR kit (Kapa Biosystems) on a Viia7 instrument (Applied Biosystems). PCR conditions were 95° C. for 20 s, followed by 40 cycles of 95° C. for 3 s and 60° C. for 30 s. Data were analyzed using the deltaCt method with hprt1 serving as the reference housekeeping gene.
Statistical Analysis—Data are expressed as mean±SEM. For the analysis of rhythmic oscillations and their amplitudes, the non-parametric test JTK_cycle was used (Hughes et al., 2010), incorporating a window of 18-24 hours for the determination of circadian periodicity. P values <0.05 were considered significant. The Benjamini-Hochberg procedure was used to control the false discovery rate. JTK_cycle results are provided in supplemental tables. Differences in metabolic data were analyzed by ANOVA, and post-hoc analysis for multiple group comparison was performed. Pairwise comparison between host transcript data was performed using student's t-test. ANOVA and t-test were performed using GraphPad Prism software.
Results
To determine the longitudinal changes of microbiota composition over the course of a day, taxonomic analysis of fecal microbiota from mice was performed every 6 hours for two light-dark cycles (
The present inventors next analyzed whether these diurnal oscillations in microbiota composition have consequences for the functional capacities of the intestinal microbial community over the course of a day. Shotgun metagenomic sequencing of fecal samples collected every 6 hours over the course of two light-dark cycles was performed and the metagenomic reads were mapped to a gut microbial gene catalogue (Qin et al., 2010). While the majority of genes showed a stable level over the course of a day, certain groups of genes (such as genes involved in flagellar assembly and glycosaminoglycan degradation,
These results suggest the existence of day time-specific profiles of microbiota functionality. Interestingly, it appeared that distinct functional groups exhibited coordinated anti-phasic fluctuations (
Together, these results uncover fluctuations in microbiota composition and function on the scale of hours, which follow 24-hour rhythmicity, and which result in robust oscillations and time of day-specific configurations.
Importantly, the observed gut microbiota diurnal rhythmicity was present despite the lack of direct microbial exposure to environmental light-dark alterations. The present inventors thus sought to determine how these rhythmic fluctuations in microbiota composition are generated in a 24-hour period. The biological clock of the host is synchronized to environmental day-night variations by the molecular components of the circadian clock. To test whether the circadian clock of the host is required for diurnal rhythmicity in microbiota composition, Per1/2−/− mice were used, which are deficient in a functional host clock (Adamovich et al., 2014). A taxonomic comparison between the microbiota of wild-type and Per1/2−/− mice was performed at each phase of the dark-light cycle over 48 hours, and the JTK_cycle algorithm was then used to identify rhythmic elements. Notably, Pert/2−/− mice demonstrated a near complete loss of rhythmic fluctuations in commensal bacterial abundance (
To determine whether the loss of compositional oscillations has any consequences for the diurnal metagenomic profile shotgun sequencing of microbiota from Per1/2−/− mice was performed and the results were compared to wild-type mice at each phase of the day. The diurnal patterns in metagenomic pathways observed in wild-type mice was non-existent in Per1/2-deficient mice (
Importantly, the present inventors also noted dysbiosis in Per1/2-deficient mice, as evident from lower alpha-diversity (
The present inventors next set out to determine the mechanism by which the circadian clock of the host is involved in generating microbial compositional oscillations in the intestine. The host circadian clock controls the rhythmicity of many physiological functions, including food consumption (Turek et al., 2005). Conversely, feeding times are central in entraining and synchronizing peripheral clocks (Asher et al., 2010; Hoogerwerf et al., 2007; Stokkan et al., 2001). Rodents are nocturnal animals that eat preferentially during the dark phase (
Consequently, if feeding times are directly controlling diurnal fluctuations in microbiota composition, then timed feeding should rescue the loss of such fluctuations in mice deficient in the circadian clock. The present inventors therefore performed a similar food restriction experiment on Per1/2−/− mice and microbiota samples were analyzed every 6 hours over two light-dark cycles after two weeks of scheduled feeding. Indeed, both light phase-fed and dark phase-fed, but not ad libitum-fed Per1/2−/− mice featured significantly oscillating bacterial OTUs, demonstrating de-novo rhythmicity generation in a formerly arrhythmic community composition (
Similar to wild-type mice undergoing timed feeding, the phase of microbiota oscillations followed the feeding time in Per1/2−/− mice, and oscillating OTUs showed phase shifts between dark phase-fed and light phase-fed mice (
To further corroborate the centrality of host feeding rhythmicity in controlling microbiota oscillations, microbiota from Per1/2−/− mice (lacking diurnal fluctuations) were transplanted into germ-free mice that were housed under normal light-dark conditions (
The present inventors next sought to test the physiological relevance of microbiota diurnal rhythmicity. In humans, disturbances of the circadian clock often occur in the setting of shift work and chronic jet lag, where external light conditions change frequently and impair the ability of the molecular clock to adapt to a stable rhythm. This situation was mimicked in mice by using a jet lag model in which mice were exposed to an 8-hour time shift every three days (
Given the finding that rhythmic food intake induces diurnal fluctuations in the microbiota, the present inventors examined whether these disruptions of rhythmic behavior by jet lag would also impair diurnal oscillations in microbiota composition. To this end, a taxonomic analysis of microbiota composition was made every 6 hours in jet lagged mice and rhythmicity was tested by JTK_cycle. Analogous to mice deficient in the circadian clock, jet lagged mice featured an abrogation of bacterial rhythms with a reduced number of oscillating bacterial taxonomic units (
Since dysbiosis was observed in genetically clock-deficient mice, the community composition of “jet lagged” mice was analyzed after 4 weeks of time shifts. Indeed, microbiota composition slightly differed between control and jet lagged mice (
Dysbiosis Associated with Environmental Clock Disruption Drives Metabolic Disease
Chronic jet lag and shift work are behavioral patterns that have become widespread in humans only recently, following the industrial revolution. These newly introduced behavioral patterns are associated with increased risk for obesity, diabetes, and cardiovascular disease, all disease states that have emerged in parallel in modern human populations (Archer et al., 2014; Buxton et al., 2012; Fonken et al., 2010; Scheer et al., 2009; Suwazono et al., 2008). Since loss of microbiota oscillations and dysbiosis were found to be associated with jet lag in mice, the present inventors set out to test whether the microbiota involved in metabolic imbalances is associated with altered circadian rhythms. They first established that jet lag is associated with manifestations of the metabolic syndrome. Jet lagged and control mice were fed a high-fat diet, containing 60% of caloric energy from fat, thereby mimicking human dietary habits predisposing to the metabolic syndrome. Indeed, as early as 6 weeks after instating of high-fat diet, time-shifted mice exhibited enhanced weight gain and exacerbated glucose intolerance as compared to mice maintained on normal circadian rhythmicity (
Since the overall food intake was not different between wild-type and jet lagged mice (
Of note, glucose tolerance by itself underlies circadian variation (Kaasik et al., 2013; So et al., 2009). Nevertheless, diurnal differences in glucose intolerance between jet lagged and control groups persisted irrespective of daily time of measurement (data not shown). Disruption of nocturnal behavior and feeding patterns in jet lagged mice was unaffected by high-fat diet or antibiotics treatment (
To further corroborate the role of the altered microbiota in the metabolic imbalances observed in jet lagged mice, fecal transfer of control or “jet lagged” microbiota configurations into germ-free Swiss Webster mice was performed. Recipients of the time-shifted microbiota exhibited enhanced weight gain and glucose intolerance as compared to control microbiota recipients (
Furthermore, similar to their respective donors, recipients of microbiota from time-shifted mice featured a significant increase in body adiposity (
Finally, the present inventors examined whether the findings in animal models may apply to humans. They first determined microbiota community variations in human fecal samples from two subjects collected at multiple time points during the day for several consecutive days (
Similar to what was found in mice, oscillating OTUs features distinct acrophases and bathyphases over the course of a day (
Furthermore, the data in mice suggests that disruption of the circadian clock by aberrant sleep-activity cycles leads to aberrant microbiota composition. The time shift model which was applied in mice corresponds to the jet lag induced by flying between countries with an 8-hour time difference. The present inventors therefore collected fecal samples from two healthy human donors who underwent such a flight-induced time shift of 8-10 hours (flying from central or western United States time zones to Israel) and performed a taxonomic analysis one day before the induction of travel-induced jet lag, during jet lag (one day after landing), and after recovery from jet lag (two weeks after landing) (
Interestingly, Firmicutes have been associated with a higher propensity for obesity and metabolic disease in multiple human studies (Ley et al., 2006; Ridaura et al., 2013). To analyze whether the microbiota changes in jet lagged individuals were associated with increased susceptibility to metabolic disease, fecal transfer experiments into germ-free mice of human samples obtained from individual subjects before jet lag, 24 hours into jet lag, and following recovery from jet lag were performed (
Germ-free mice colonized with microbiota from jet lagged individuals displayed enhanced weight gain and featured higher blood glucose levels after oral glucose challenge compared to samples taken before the time-shift (
Furthermore, germ-free recipients of microbiota from the jet lagged state accumulated more body fat than mice receiving microbiota from the same subjects before or after jet lag (
In this example, the present inventors describe that the mammalian gut microbiota displays diurnal oscillations which are governed by food consumption rhythmicity. If rhythmic feeding times are distorted, as in the case of genetic clock deficiency or time shift-induced jet lag, then microbiota oscillations are impaired (
Previous studies looking at temporal fluctuations in the microbiota have considered longer time frames, and found a remarkable stability of individual microbial compositions over time (Faith et al., 2013; Lozupone et al., 2012). Here, the present inventors performed the longitudinal microbiota study with a finer temporal resolution and found an hour-scale fluctuation with a diurnal rhythm. Notably, the analysis here focuses on the diurnal variations in microbial community composition and metagenomic pathways. Since molecular components of bacterial circadian clocks have also been described to function on the transcriptional and post-transcriptional level (Lenz and Sogaard-Andersen, 2011), it is possible that some members of the commensal microbiota harbor yet another level of time-dependent activity control, which, in addition to the patterns in relative abundance, might regulate bacterial activity in a rhythmic manner.
These results have several implications. First, they suggest that the metabolic imbalances associated with chronic disturbances of host circadian rhythms, such as the ones found in shift workers and during jet lag, have a communicable component that depends on the composition of the microbiota and its effect on host metabolism. The highly multifactorial morbidities associated with disruptions of host circadian rhythms are emerging diseases of the modern life style, and the underlying etiology is poorly understood. The present study identifies alterations in intestinal microbial communities as an additional driving force of such disease manifestations and implies that targeted probiotic or antimicrobial therapy may be tested as potential new preventive or therapeutic approaches in susceptible populations. In addition, the results yield new insight into earlier studies on mice with deficiencies in the circadian clock (Karatsoreos et al., 2011; Rudic et al., 2004; Turek et al., 2005), as some of the discovered phenotypes might not be mediated solely by the genetic deficiency, but may additionally be influenced by changes in the characteristics of the microbiota and downstream metabolic and inflammatory consequences. The results presented here may thus prompt future studies to determine the impact of circadian misalignment on factors shaping the microbiota, including immune and metabolic pathways of the host, eating patterns, stress hormone levels, and bowel movement.
Second, the present study reveals that, in addition to the type of diet being a modulator of microbiota composition, the timing of food intake plays a critical role in shaping intestinal microbial ecology. When food intake is rhythmic, it was found that up to 15% of commensal bacterial taxonomic units (and a much higher percentage of abundance) fluctuate over the course of a day. In host peripheral tissues such as the liver, a similar proportion of all transcripts oscillate in a rhythmic manner (Akhtar et al., 2002; McCarthy et al., 2007; Panda et al., 2002; Storch et al., 2002; Vollmers et al., 2009). Analogous to peripheral clocks, the microbiota rhythms are influenced by the host clock and perform critical functions in the adaptation of metabolic processes to the diurnal fluctuations in the environment. Indeed, recent work has shown that cues from the microbiota play an important role in the generation of circadian rhythms in intestinal epithelial cells (Mukherji et al., 2013). Together, this recent work and the present study suggest an emerging new paradigm whereby a feedback loop between diurnal oscillations of the host and the microbiota with mutual cross-regulation of interdependent functions.
The present observation that food rhythmicity directs microbiota oscillations might also be noteworthy in another regard. It is a well-established concept that, in addition to being synchronized to the light-sensitive central oscillator, peripheral clocks are entrained by feeding rhythms. Based on the well-documented role of the microbiota as a modulator of host gene expression, these results raise the possibility that the microbiota might be involved in this process of food entrainment and might suggest an additional mechanistic explanation for earlier observations of the beneficial metabolic effects associated with timed feeding (Adamovich et al., 2014; Damiola et al., 2000; Vollmers et al., 2009). In such a scenario, rhythmic food intake may govern microbiota oscillations, which in turn causes rhythmic induction of host gene expression. The impact of the microbiota and its oscillations on host circadian behavior and gene expression thus presents an exciting field of future research.
In addition, the diurnal fluctuations in intestinal microbial ecology discovered here should be taken into account when interpreting studies focusing on human and animal microbiota composition. For instance, based on the present results, it might be advisable that human subjects involved in microbiota studies provide their samples at a standardized time of the day in order to exclude the effect of diurnal variations on the interpretation of diet or treatment modalities. The present study reveals that dysbiosis has a temporal dimension, and that static microbiota comparisons might not be fully conclusive, unless samples were taken in a controlled manner with respect to this important additional variable. Short-term rhythmic oscillations in the microbiota, such as the ones described in this study, may be exaggerated or disrupted under various disease conditions, and it will be interesting to determine the impact of such “temporal dysbiosis” on microbiota-mediated diseases with different manifestations or varying degrees of severity at different phases of the day.
Finally, the network of co-dependent diurnal rhythms, which the host and its indigenous microbiota have evolved might confer several biological advantages to the meta-organism. A dynamic microbiota composition may be able to meet the challenges imposed by diurnal fluctuations in the environment better than a temporally static composition. As demonstrated in this study, food intake by the host undergoes circadian fluctuations, which evoke temporal changes in the bacterial species involved in nutrient metabolism. Thus, oscillations in components of the microbiota might anticipate these temporal variations in nutrient availability. The metagenomic analysis suggests that certain categories of bacterial functions feature temporal predilections of the course of a day (
Materials and Methods
Mice—C57Bl/6 WT adult male mice were randomly assigned (without blinding) to treatment groups and were given commercial artificial sweeteners (saccharin-, sucralose- or aspartame-based) or pure saccharin (Sigma Aldrich) in drinking water and fed a high-fat (HFD D12492, 60% Kcal from fat, Research Diets) or standard polysaccharide normal chow (NC) diet (Harlan-Teklad). Compared groups were always fed from the same batch of diet. For antibiotic treatment, mice were given a combination of ciprofloxacin (0.2 gl−1) and metronidazole (1 gl−1) or vancomycin (0.5 gl−1) in their drinking water. All antibiotics were obtained from Sigma Aldrich. Adult male outbred Swiss-Webster mice (a widely used mouse strain in germ-free experiments) served as recipients for fecal transplants and were housed in sterile isolators (Park Biosciences). For fecal transplantation experiments, 200 mg of stool (from mouse pellets or human swabs) was resuspended in 5 ml of PBS under anaerobic conditions, vortexed for 3 minutes and allowed to settle by gravity for 2 minutes. Recipient mice were gavaged with 200 μl of the supernatant and maintained on standard NC diet and water throughout the experiment.
Artificial and caloric sweeteners—The following commercially available NAS were dissolved in mice drinking water to obtain a 10% solution: Sucrazit (5% saccharin, 95% glucose), Sucralite (5% Sucralose), Sweet'n Low Gold (4% Aspartame). 10% glucose (J.T. Baker) and 10% sucrose (Sigma Aldrich) solutions were used for controls. The administered doses of 10% commercial NAS dissolved in water were well below their reported toxic dose (6.3 gkg−1 51 16 gkg−1 52, and 4 gkg−1 53, for saccharin, sucralose and aspartame, respectively). For experiments conducted with pure saccharin (Sigma Aldrich) a 0.1 mgml−1 solution was used in order to meet with FDA defined ADI for saccharin in humans (5 mgkg−1), according to the following calculation:
Glucose and insulin tolerance tests—Mice were fasted for 6 hours during the light phase, with free access to water. In all groups of mice where the drinking regime was other than water, it was substituted for water for the period of the fasting and glucose or insulin tolerance test. Blood from the tail vein was used to measure glucose levels using a glucometer (Bayer) immediately before and 15, 30, 60, 90 and 120 minutes after oral feeding with 40 mg glucose (J.T. Baker) or intra-peritoneal injection with 0.1 Ukg−1 Insulin (Biological Industries). Plasma fasting insulin levels were measured in sera collected immediately before the start of GTT using ELISA (Ultra Sensitive Mouse Insulin ELISA Kit, Crystal Chem).
Metabolic studies—Food and drink intake and energy expenditure were measured using the PhenoMaster system (TSE-Systems, Bad Homburg, Germany), which consists of a combination of sensitive feeding sensors for automated measurement and a photobeam-based activity monitoring system detects and records ambulatory movements, including rearing and climbing, in each cage. All parameters were measured continuously and simultaneously. Mice were trained singly-housed in identical cages prior to data acquisition. To calculate total caloric intake, the following values were used: Chow 3 kcalg−1, sucrose 0.3938 kcalml−1, glucose 0.4 kcalml−1, saccharin 0.38 kcalml−1, sucralose 0.392 kcalml−1 and aspartame 0.38 kcalml−1.
In vitro anaerobic culturing—pooled fecal matter from naïve adult WT C57Bl/6 male mice was resuspended in 5 ml PBS in an anaerobic chamber (Coy Laboratory Products, 75% N2, 20% CO2, 5% H2), vortexed for 3 minutes and allowed to settle by gravity for 2 minutes. 500 ml of the supernatant were added to a tube containing Chopped Meat Carbohydrate Broth, PR II (BD) and 500 ml of a 5 mgml-1 saccharin solution or an equal volume of PBS. Every 3 days, 500 ml of culture were diluted to fresh medium containing saccharin or PBS. After 9 days, cultures were used for inoculation of germ-free mice.
Taxonomic microbiota analysis—Frozen fecal samples were processed for DNA isolation using the MoBio PowerSoil kit according to the manufacturer's instructions. 1 ng of the purified fecal DNA was used for PCR amplification and sequencing of the bacterial 16S rRNA gene. ˜365 bp Amplicons spanning the variable region 2 (V2) of the 16S rRNA gene were generated by using the following barcoded primers: Fwd 5′-AGAGTTTGATCCTGGCTCAG-3′ (SEQ ID NO: 3), Rev 5′-TGCTGCCTCCCGTAGGAGT-3′ (SEQ ID NO: 4). The reactions were subsequently pooled in an equimolar ratio, purified (PCR clean kit, Promega), and used for Illumina MiSeq sequencing to a depth of at least 18000 reads per sample (mean reads per sample 139148±5264 (SEM)). Reads were then processed using the QIIME (Quantitative Insights Into Microbial Ecology) analysis pipeline as described, version 1.8. Paired-end joined sequences were grouped into operational taxonomic units (OTUs) using the UCLUST algorithm and the greengenes database. Sequences with distance-based similarity of 97% or greater over median sequence length of 353 bp were assigned to the same OTU. Samples were grouped according to the treatment. Analysis was performed at each taxonomical level (Phylum-genus+OTU level) separately. For each taxon, G test was performed between the different groups. P-values were FDR corrected for multiple hypothesis testing.
Shotgun pyrosequencing and sequence mapping—Was performed as previously described57, with the following modifications: 1 ug of DNA was sheared using the Covaris 5200 system (Covaris, Inc., Woburn, Mass., USA), followed by end repair, ligation to adapters, an 8 cycle PCR amplification (Kappa HiFi) and sequenced using an Illumina HiSeq to a minimal depth of 11773345 reads per sample (mean reads per sample 20296086±637379 (SEM), read length 51 bp). Illumina sequence reads were mapped to the human microbiome reference genome database of the Human Microbiome Project [www(dot)hmpdacc(dot)org/HMREFG/32], and to a gut microbial gene catalogue33 using GEM mapper58 with the following parameters:
Microbial species abundance was measured as the fraction of reads that mapped to a single species in the database. An EM algorithm adapted from Pathoscope59 was employed to determine the correct assignment of reads that mapped to more than one species. We considered only species for which at least 10% of the genome was covered (each coverage bin was 10,000-bp long) in at least one of the growth conditions (saccharin, water, or glucose). Reads mapped to the gut microbial gene catalogue were assigned a KEGG34,35 ID according to the mapping available with the catalogue. Genes were subsequently mapped to KEGG pathways, and only pathways whose gene coverage was above 0.2 were included. To calculate the contribution of different bacteria to the overrepresentation of glycan degradation pathways, reads that were mapped to genes in the gut microbial gene catalogue that belong to glycan degrading pathways were extracted and re-mapped the HMP reference genome database, seeking germs that had the highest contribution.
Short chain fatty acid quantification—to determine the level of free fatty acids analytic HPLC (Agilent 1260) was performed as described previously60. In brief, standard solutions of Acetate, Butyrate and Propionate (all from Sigma-Aldrich) were prepared at various concentrations (0.01-0.2 M). These solutions were analyzed using HPLC, successive with QTOF-Mass Spec with a step-gradient of solvent solution from 0% to 60% of CH3CN with 0.1% formic acid to obtain calibration curve for each fatty acid. Fecal Media samples were dissolved with 0.1% formic acid analyzed in similar manner to measure the total concentration of all three free fatty acids.
Analysis of the Relationship Between NAS Consumption and Clinical Parameters in Humans:
The trial was reported to clinical trials, identifier NCT01892956. The study did not necessitate or involve randomization. For each individual in the clinical nutritional study, after signing an informed consent, the parameters collected include BMI, body circumferences, fasting glucose levels, general questionnaire, complete blood counts and general chemistry parameters, a validated long-term food frequency questionnaire44,61,62.
Long-term NAS consumption was quantified directly from answers to an explicit question regarding artificial sweeteners that participants filled out in their food frequency questionnaire. Spearman correlation was then used to examine the relationship between NAS consumption and each of the above parameters, and FDR corrected for the multiple hypotheses tests performed.
Statistics—The following statistical analyses were used: in GTT, a two-way ANOVA and Bonferroni post-hoc analysis were used to compare between groups in different time-points, and one-way ANOVA and Tukey post hoc analysis or unpaired two-sided Student t-test were used to compare between AUC of multiple or two groups, respectively. Bartlett's or F-test for equal variance were employed and no significant difference was observed between variances of the compared groups. For comparison of taxonomic data, a G-test was used and P-values were FDR corrected for multiple hypothesis testing. In metagenomics and clinical and taxonomic data from humans, Pearson and Spearman were used for correlation tests, and Mann-Whitney U was used to compare clinical parameters between groups. p<0.05 was considered significant in all analyses (* denotes p<0.05, **, p<0.01, ***, p<0.001). In all relevant panels, symbols or horizontal lines represent the mean, and error bars S.E.M. For mouse experiments, cohort sizes match common practice of the described experiments. For human experiments, sample size was chosen to validate statistical analyses. No mice or data points were excluded from analyses. In the human studies, all humans older than 18 years of age who enrolled were included. Exclusion criteria included pregnancy.
To determine the effects of NAS on glucose homeostasis, we added commercial formulations of saccharin, sucralose or aspartame to the drinking water of lean 10-week-old C57Bl/6 mice (
As saccharin exerted the most pronounced effect, we further studied its role as a prototypical artificial sweetener. To corroborate the findings in the obesity setup, we fed C57Bl/6 mice a high-fat diet (HFD, 60% Kcal from fat) while consuming either commercial saccharin or pure glucose as a control (
Metabolic profiling of NC- or HFD-fed mice in metabolic cages, including liquids and chow consumption, oxygen consumption, walking distance and energy expenditure, showed similar measures between NAS- and control-drinking mice (
Since diet modulates the gut microbiota15, and microbiota alterations exert profound effects on host physiology and metabolism, the present inventors tested whether the microbiota may regulate the observed NAS effects. To this end, they treated mouse groups consuming commercial or pure NAS in the lean and HFD states (
To test whether the microbiota role is causal, fecal transplantation experiments were performed, by transferring the microbiota configuration from mice on NC diet drinking commercial saccharin or glucose (control) into NC-consuming germ-free mice (
The present inventors next examined the fecal microbiota composition of the various mouse groups by sequencing their 16S rRNA gene. Mice drinking saccharin had distinct microbiota composition that clustered separately from both their starting microbiome configurations and from all control groups at week 11 (
To study the functional consequences of NAS consumption, shotgun metagenomic sequencing of fecal samples was performed from before and after 11 weeks of commercial saccharin consumption, as compared to control mice consuming either glucose or water. To compare relative species abundance, sequencing reads were mapped to the human microbiome reference genome database16. In agreement with the 16S rRNA analysis, saccharin treatment induced the largest changes in microbial relative species abundance (
The present inventors next mapped the metagenomic reads to a gut microbial gene catalogue, evenly dividing reads mapping to more than one gene, and then grouping genes into KEGG pathways. Examining pathways with gene coverage above 0.2 (115 pathways), changes in pathway abundance were inversely correlated between commercial saccharin- and glucose-consuming mice (R=−0.45, p<10−6,
In addition to glycan degradation, and in-line with previous studies on humans with T2DM13,20, other pathways were enriched in microbiomes of saccharin consuming mice, including starch and sucrose metabolism, fructose and mannose metabolism, and folate-, glycerolipid- and fatty acid biosynthesis (Table 2, herein below), while glucose transport pathways were underrepresented in saccharin-consuming mice (
Altogether, saccharin consumption results in distinct diet-dependent functional alterations in the microbiota, including NC-related expansion in glycan degradation contributed by several of the increased taxa, ultimately resulting in elevated stool SCFA levels, characteristic of increased microbial energy harvest11.
To determine whether saccharin directly affects the gut microbiota, the present inventors cultured fecal matter from naïve mice under strict anaerobic conditions (75% N2, 20% CO2, 5% H2) in the presence of saccharin (5 mgml−1) or control growth media. Cultures from day 9 of incubation were administered by gavage to germ-free mice (
Shotgun metagenomic sequencing analysis revealed that in-vitro saccharin treatment induced similar functional alterations to those found in mice consuming commercial saccharin (
Collectively, these results demonstrate that saccharin directly modulates the composition and function of the microbiome and induces dysbiosis, accounting for the downstream glucose intolerance phenotype in the mammalian host.
To study the effect of NAS in humans, the relationship between long-term NAS consumption (based on a validated food frequency questionnaire, see methods) and various clinical parameters in data collected from 381 non-diabetic individuals (44% males and 56% females; Age 43.3±13.2) in an ongoing clinical nutritional study was compared. Significant positive correlations between NAS consumption and several metabolic syndrome-related clinical parameters were found (Table 4, herein below), including increased weight & waist-hip ratio (measures of central obesity); higher fasting blood glucose, glycosylated hemoglobin (HbA1C %) & glucose tolerance test (GTT, measures of impaired glucose tolerance), and elevated serum alanine aminotransferase (ALT, measure of hepatic damage that is likely to be secondary, in this context, to non-alcoholic fatty liver disease). Moreover, the levels of glycosylated hemoglobin (HbA1C %), indicative of glucose concentration over the previous 3 months, were significantly increased when comparing a subgroup of high NAS consumers (40 individuals) to non-NAS consumers (236 individuals,
Finally, as an initial assessment of whether the relationship between human NAS consumption and blood glucose control is causative, seven healthy volunteers (5 males and 2 females, aged 28-36) who do not normally consume NAS or NAS-containing foods were followed for one week. During this week, participants consumed on days 2-7 the FDA's maximal acceptable daily intake (ADI) of commercial saccharin (5 mgkg−1) as 3 divided daily doses equivalent to 120 mg, and were monitored by continuous glucose measurements and daily GTT (
The microbiome configurations of NAS responders, as assessed by 16S rRNA analysis, clustered differently from non-responders both prior to and following NAS consumption (
In summary, our results suggest that NAS consumption in both mice and humans enhances the risk of glucose intolerance and that these adverse metabolic effects are mediated by modulation of the composition and function of the microbiota. Notably, several of the bacterial taxa that changed following NAS consumption were previously associated with T2DM in humans13,20, including over-representation of Bacteroides and under-representation of Clostridiales. Both gram positive and negative taxa contributed to the NAS-induced phenotype (
Our results from short and long-term human NAS consumer cohorts (
Materials and Methods
Mice: C57Bl/6 mice were purchased from Harlan and allowed to acclimatize to the local animal facility for 2 weeks before used for experimentation. Mice were kept under strict light-dark cycles, with lights being turned on at 6 am and turned off at 6 pm. In all experiments, age- and gender-matched mice were used. Mice were 8-9 weeks of age at the beginning of experiments. Generally, both male and female mice were used. Stool samples, fecal content, and tissue samples were collected fresh and on the basis of individual mice. Fresh samples were collected in tubes, immediately frozen in liquid nitrogen upon collection, and stored at −80° C. until RNA or DNA isolation. In food timing experiments, mice were housed under standard light-dark conditions (6 am to 6 pm), but had access to food only during the light or dark phase, respectively, for 2 weeks. For antibiotic treatment, mice were given a combination of vancomycin (0.5 g/l), ampicillin (1 g/l), kanamycin (1 g/l), and metronidazole (1 g/l) in their drinking water. All antibiotics were obtained from Sigma Aldrich. Antibiotics were given continuously for one week. For experiments involving genotobiotic mice, germ-free Swiss Webster mice were housed in sterile isolators. All experimental procedures were approved by the local IACUC.
RNA-seq: Tissues were preserved in RNAlater solution (Ambion) and subsequently homogenized in Trizol reagent (Invitrogen). RNA was purified according to the manufacturer's instructions. 400 ng of total RNA were used for library preparation. mRNA was captured with 12 μl of Dynabeads oligo(dT) (Life technologies), and washed according to the manufacture's guidelines. Purified messenger RNA was eluted at 70° C. with 10 μl of 10 mM Tris-Cl pH 7.5. cDNA was generated from 1 μl of mRNA of each sample. cDNA quantity in each sample was evaluated by qPCR for Actin B gene, and then equivalent amounts of mRNA of each sample were taken for RNAseq library construction. Library construction was performed in a 96-well plate format. First, to open secondary RNA structures and allow annealing of the RT primer, the samples were incubated at 72° C. for 3 min and immediately transferred to 4° C. Then, RT reaction mix (10 mM DTT, 4 mM dNTP, 2.5 U/μl Superscript III RT enzyme in 50 mM Tris-HCl (pH 8.3), 75 mM KCl, 3 mM MgCl2) was added into each well of the 96-well plate and the reaction was mixed. The 96-well plate was then spun down and moved into a cycler (Eppendorf) for the following incubation: 2 min at 42° C., 50 min at 50° C., 5 min at 85° C. Indexed samples with equivalent amount of cDNA were pooled and the product was purified with 1.4× volumes of SPRI beads. The library was completed and amplified through a 12-cycle PCR reaction with 0.5 μM of P5_Rd1 and P7_Rd2 primers and PCR ready mix (Kapa Biosystems). The forward primer contains the Illumina P5-Read1 sequences and the reverse primer contains the P7-Read2 sequences. The amplified pooled library was purified with 0.7× volumes of SPRI beads to remove primer leftovers. Library concentration was measured with a Qubit fluorometer (Life Technologies) and mean molecule size was determined with a 2200 TapeStation instrument (Agilent). Libraries were sequenced using an Illumina HiSeq 1500. Reads were analyzed as previously described (Lavin et al., 2014) and normalized to the number of total reads for equal coverage across samples. Only genes with more than 10 reads per sample were considered for analysis.
Quantification of bacterial DNA: Luminal and mucosal-adherent communities were harvested by extensive flushing of the intestinal lumen to remove non-adherent commensal bacteria. DNA was extracted from the luminal and mucosal fractions using the MoBio PowerSoil kit. DNA concentration was calculated using a standard curve of known DNA concentrations from E. coli K12. 16S qPCR using primers identifying different regions of the V6 16S gene was performed using SYBR fast mix (Kapa Biosystems). The absolute number of bacteria in the samples was then approximated as DNA amount in a sample/DNA molecule mass of bacteria.
Scanning Electron Microscopy: Mice were perfused with fixative containing 2% glutaraldehyde and 3% PFA in 0.1 M sodium cacodylate. Colonic samples were extensively washed from fecal matter and fixed for 1-2 hr. Samples were rinsed three times in sodium cacodylate buffer and postfixed in 1% osmium tetroxide for 1 hr, stained in 1% uranyl acetate for a further hour, then rinsed, dehydrated, and dried using critical point drying. Samples were then gold-coated and viewed in an ULTRA 55 FEG (ZEISS). For image quantification, the number of bacteria on 10 randomly selected fields per sample were counted and averaged.
Metabolomics: Metabolomics analysis was carried out by Metabolon, Inc (Morrisville, N.C.). Samples were analyzed by Ultrahigh Performance Liquid Chromatography-Tandem Mass Spectroscopy (UPLC-MS/MS), and Gas Chromatography-Mass Spectroscopy (GC-MS). The LC/MS portion of the platform was based on a Waters ACQUITY ultra-performance liquid chromatography (UPLC) and a Thermo Scientific Q-Exactive high resolution/accurate mass spectrometer interfaced with a heated electrospray ionization (HESI-II) source and Orbitrap mass analyzer operated at 35,000 mass resolution. The sample extract was dried then reconstituted in acidic or basic LC-compatible solvents, each of which contained 8 or more injection standards at fixed concentrations to ensure injection and chromatographic consistency. One aliquot was analyzed using acidic positive ion optimized conditions and the other using basic negative ion optimized conditions in two independent injections using separate dedicated columns (Waters UPLC BEH C18-2.1×100 mm, 1.7 μm). Extracts reconstituted in acidic conditions were gradient eluted from a C18 column using water and methanol containing 0.1% formic acid. The basic extracts were similarly eluted from C18 using methanol and water, however with 6.5 mM Ammonium Bicarbonate. The third aliquot was analyzed via negative ionization following elution from a HILIC column (Waters UPLC BEH Amide 2.1×150 mm, 1.7 μm) using a gradient consisting of water and acetonitrile with 10 mM Ammonium Formate. The MS analysis alternated between MS and data-dependent MS2 scans using dynamic exclusion, and the scan range was from 80-1000 m/z. The samples destined for analysis by GC-MS were dried under vacuum for a minimum of 18 h prior to being derivatized under dried nitrogen using bistrimethyl-silyltrifluoroacetamide. Derivatized samples were separated on a 5% diphenyl/95% dimethyl polysiloxane fused silica column (20 m×0.18 mm ID; 0.18 um film thickness) with helium as carrier gas and a temperature ramp from 60° to 340° C. in a 17.5 min period. Samples were analyzed on a Thermo-Finnigan Trace DSQ fast-scanning single-quadrupole mass spectrometer using electron impact ionization (EI) and operated at unit mass resolving power. The scan range was from 50-750 m/z. Raw data was extracted, peak-identified and QC processed. Compounds were identified by comparison to library entries of purified standards or recurrent unknown entities. Furthermore, biochemical identifications were based on three criteria: retention index within a narrow RI window of the proposed identification, accurate mass match to the library+/−0.005 amu, and the MS/MS forward and reverse scores between the experimental data and authentic standards. The MS/MS scores are based on a comparison of the ions present in the experimental spectrum to the ions present in the library spectrum. Peaks were quantified using area-under-the-curve. For studies spanning multiple days, a data normalization step was performed to correct variation resulting from instrument inter-day tuning differences. For analysis, values were normalized in terms of raw area counts and afterwards rescaled to set the median equal to 1.
Taxonomic Microbiota Analysis: Adherent bacterial communities were obtained by serially washing colons from their luminal content, followed by snap-freezing of the mucosal layer in liquid nitrogen. Frozen samples were processed for DNA isolation using the MoBio PowerSoil kit according to the manufacturer's instructions. 1 ng of the purified fecal DNA was used for PCR amplification and sequencing of the bacterial 16S rRNA gene. Amplicons spanning the variable region 1/2 (V1/2) of the 16S rRNA gene were generated by using the following barcoded primers: Fwd 5′-NNNNNNNNAGAGTTTGATCCTGGCTCAG-3′ (SEQ ID NO: 1), Rev 5′-TGCTGCCTCCCGTAGGAGT-3′ (SEQ ID NO: 2), where N represents a barcode base. The reactions were subsequently pooled in an equimolar ratio, purified (PCR clean kit, Promega), and used for Illumina MiSeq sequencing. 500 bp paired-end sequencing was employed. An in-house script was used to assembly the paired-end reads. Assembly rates of 90% were achieved in all experiments. Reads were then processed using the QIIME (Quantitative Insights Into Microbial Ecology www(dot)qiime(dot)org) analysis pipeline (Caporaso et al., 2010). In brief, fasta quality files and a mapping file indicating the barcode sequence corresponding to each sample were used as inputs, reads were split by samples according to the barcode, taxonomical classification was performed using the RDP-classifier, and an OTU table was created. We employed open-reference OTU mapping using the Greengenes database. No non-matching nucleotides were allowed on the total paired-end assembled read length of 359 bp. Rarefaction was performed to exclude samples with insufficient reads per sample counts. Sequences sharing 97% nucleotide sequence identity in the V2 region were binned into operational taxonomic units (97% ID OTUs). For beta-diversity, unweighted unifrac measurements were plotted according to the first two principal coordinates based on 1,000 reads per sample.
Metagenomic Sequence Mapping: Illumina sequencing reads were mapped to a gut microbial gene catalog (Human Microbiome Jumpstart Reference Strains et al., 2010) using GEM mapper (Marco-Sola et al., 2012) with the following parameters: -m 0.08 -s 0 -q offset-33 -gem-quality-threshold 26.
Functional Assignment: Reads mapped to the gut microbial gene catalog were assigned a KEGG (Kanehisa and Goto, 2000) identification number, according to the gene to category mapping that accompanied the gene catalog. Genes were subsequently mapped to KEGG modules and pathways. Only genes with more than 10 assigned reads were considered. For the KEGG pathway analysis, only pathways whose gene coverage was above 0.2 were included. KEGG pathways were then tested by JTK_cycle for daily oscillations.
Statistical Analysis: Data are expressed as mean±SEM. For the analysis of rhythmic oscillations and their amplitudes, the non-parametric test JTK_cycle was used in R (Hughes et al., 2010), allowing 24 hr for the determination of circadian periodicity. For the detection of rhythmic metabolites, metagenomic content, and transcripts, p<0.05 and q<0.2 was considered significant. Chow-Ruskey diagrams were generated in R using the Vennerable package. Hypergeometrical testing for KEGG pathway enrichment analysis was done using DAVID (Huang da et al., 2009).
Results
Diurnal Rhythms of Microbiota Biogeographical Localization
The intestinal microbiota undergoes rhythmic oscillations in composition and gene content, but the mechanisms by which these functional microbial oscillations impact the host remain elusive. Since commensal bacteria most strongly affecting the host are believed to be located in close proximity to the intestinal mucosal surface, the present inventors sought to study the bio-geographical aspects of microbiome diurnal rhythmicity. They therefore analyzed fluctuations in the abundance of epithelial-adherent commensal bacteria over the course of two days (
Diurnal Rhythms of the Intestinal Metabolome
In order to determine whether diurnal rhythmicity occurs within the host-microbiome interface, in which intense and intimate communication occurs primarily through the exchange and sensing of metabolites, the temporal dynamics of the intestinal metabolome was determined by metabolite profiling in wild-type mice every 6 hours over the course of two light-dark cycles (
The Microbiota Programs Colonic Transcriptome Oscillations
To globally determine the regulatory roles that the microbiota plays on oscillatory processes of the host, mice were administered with broad-spectrum antibiotics the impact of microbiota depletion on meta-organismal diurnal oscillations was determined (
Coordinated Meta-Organismal Oscillations are Driven by Feeding Times
To determine whether rhythmic food intake controls the rhythmic activity of commensals, timed feeding experiments were performed. In these, mice (which preferentially consume food during the dark phase,
Rhythmic feeding also reprogrammed the colonic transcriptome, as has been previously noted for the liver (Vollmers et al., 2009), while keeping a constant total number of oscillating elements (
Feeding Times, the Microbiota, and Host Genetics Jointly Orchestrate the Cyclic Transcriptome
Given the finding that both the microbiota and feeding times are able to program colonic transcriptome oscillations, the present inventors next addressed the interplay between both types of environmental influences on host circadian function. To determine the resemblance and inter-dependency between feeding rhythmicity disruption-induced and microbiome-depletion induced host transcriptome reprogramming, a quadruple comparison of unique and shared oscillating transcripts between mice on timed feeding, both with and without additional antibiotic treatment was performed (
The present results indicate that the presence of the microbiota is critical for the maintenance of colonic transcriptome oscillations. To understand whether the necessity for microbiota in driving host circadian activity stems from only its presence or from its diurnally fluctuating activity, the present inventors took advantage of the finding that compositional microbial oscillations cease to be present in the absence of a functional host circadian clock, but can be restored by rhythmic feeding (Thaiss et al., 2014b). They thus performed a scheduled feeding experiment on Per1/2-deficient mice, which lack essential components of the molecular clock (
The Microbiota Programs the Hepatic Clock
Finally, we sought to determine whether the effects mediated by the diurnally oscillating gut microbiome on the intestinal oscillating transcriptome program could be systemically transmitted. Such distant microbiome-induced regulatory effects on the host circadian rhythmicity would be of potential pathophysiological relevance. We chose to focus on the effects of microbiome diurnal activity on liver circadian rhythmicity, as microbiome impacts on hepatic physiology and liver disease have been documented in multiple recent studies, while many of the mechanisms for such distal effects remain elusive (Henao-Mejia et al., 2012; Qin et al., 2014). To assess whether hepatic transcriptome reprogramming is impacted by microbiota disruption, mice were treated for one week with broad spectrum antibiotic treatment, the hepatic rhythmic transcription of naïve or antibiotics-treated mice was profiled using JTK_cycle, with p<0.05 and q<0.2 as threshold (
In this example, diurnal rhythmicity is identified as an essential component in the regulation of host-microbiota symbiosis. Two new elements of microbiota oscillatory activity have been identified that provide a mechanistic explanation for its functional importance: oscillations in biogeographical localization and metabolite secretion patterns. Rhythmically coordinated functions such as bacterial motility and mucus degradation establish a temporal pattern of mucosal adherence of defined microbiota members, inducing a homeostatic state in with the host is periodically exposed to different bacterial numbers, species, functions, and products at different times of the day. In response, the host exerts a rhythmic metabolic and immune program in synchrony to corresponding microbial activity (
These findings have numerous important implications. First, exchange of metabolites is increasingly recognized as a major means of communication between the microbiota and the host, thereby creating a meta-organism-wide network of metabolic and immune cross-talk and interdependency. This is exemplified by metabolite-induced regulation of host physiology and molecular recognition of microbial presence by receptors of the innate immune system. All such functions critically depend on the biogeographical localization of the microbiota, and thus the regulatory mechanisms that underlie microbiota stratification in the intestinal ecosystem may hold the key for understanding how microbial colonization within the host is established and maintained. The present findings demonstrate that the time of day dramatically influences all three parameters: a given time of the day features unique profiles of metabolome, microbial composition, and mucosal adherence, resulting in a time-specific host transcriptional program highlighting distinct immune and metabolic functions at different diurnal periods. Microbial-derived molecules may also shape systemic circadian metabolomic patterns, which have been recently found to harbor rhythmic behavior, by diurnally contributing essential microbial-produced or -modulated compounds like essential amino acids and vitamins.
Consequently, the present results suggest that host-microbiome interactions in the steady state, currently regarded as static, may in fact be viewed as a constantly altering yet tightly coupled and highly regulated state of ‘fluctuating homeostasis’. Moreover, it may be suggested that these diurnal functional and compositional microbial properties are also important in determining the host response to loss of microbiota homeostasis (such as during exposure to antibiotics). Thus, the present results suggest that the kinetics of microbiota function needs to be taken into consideration when interpreting the downstream effects of microbiota-modulating dietary and medical interventions.
Second, the identification of coordinated diurnal rhythmicity between corresponding host and microbial metabolic activity adds an unexpected facet to our understanding of host-microbial co-evolution. The microbial induction of host transcript oscillations might be functionally beneficial for the meta-organismal ecosystem in at least two ways. On the one hand, by synchronizing its metabolic activity to diurnal fluctuations of the microbiome, the host may optimize the uptake and processing of essential microbiota-derived compounds, such as nutrients and vitamins. On the other hand, coordinated meta-organismal metabolic and immune activity may be ideally suited to meet the fluctuations imposed on the ecosystem by the introduction of nutrients, noxious xenobiotics, and pathogens. Furthermore, the hour-scale changes in colonization conditions along the colonic mucosa create a dynamic niche for commensals and might support long-term community stability by short-term oscillations around a stable colonization state. As such, the concerted meta-organismal activity identified in this study may provide an example for active niche construction by the microbiota, which occurs periodically over the course of 24 hours.
Furthermore, this study provides support for the notion that the circadian program of transcriptome oscillations in peripheral clocks is not independent of environmental signals, and provides a new perspective on the integration of these signals. Previous studies have indicated that both the timing of food intake and the type of diet determine circadian programming of the peripheral transcriptome. It has now been found that the microbiota plays an equally important role in the orchestration of transcriptome oscillations, by inducing and suppressing transcript cycling, both jointly and independently of feeding times (
Finally, the present study provides new insight into the multifaceted effects of antibiotic usage on mammalian physiology. Frequent disruption of the microbiome by massive antibiotic exposure has become a hallmark of both modern human medical practice and industrialized food preparation. In addition to the well explained direct deleterious effect on microbiome diversity and susceptibility to pathogenic infection, such exposure is also associated with a variety of adverse metabolic derangements (Ayres et al., 2012; Cox et al., 2014; Ng et al., 2013; Zeissig and Blumberg, 2014), yet these indirect systemic antibiotic effects remain poorly understood. It is found that antibiotics-mediated disruption of multiple levels of microbiota diurnal rhythmicity is associated with abrogation of the normal temporal sequence of both colonic and hepatic host metabolic activity over the course of a day, generating a temporal de-synchronization compared to the homeostatic daily activity profile. This finding implies that the effects of antibiotics on host physiology far exceed those exerted directly on the microbiome (such as emergence of drug resistant and opportunistic infections) as well as direct antibiotic-mediated adverse effects. Rather, antibiotic-induced dysbiosis uncouples the microbial and host coordinated rhythmicity, resulting in a massive loss and gain of host transcriptional activity. This misalignment of pathway activity, noted in both gut and liver, may result in altered functions that range from impaired or untimely hepatic detoxification, catabolism, and synthetic function, to altered immunity, potentially leading to long-term consequences such as the association between childhood antibiotic treatment and susceptibility to obesity (Cox et al., 2014).
Materials and Methods
16 impaired glycemic response and healthy participants engaged in a three week experiment of diet intervention. The first week was a profiling week, from which two personalized test diets were computed: (1) one full week of a personalized diet predicted to have “good” (low) postprandial blood glucose responses; and (2) one full week of a personalized diet predicted to have “bad” (high) postprandial blood glucose responses. The present inventors evaluated whether indeed the personalized diet of the “good” week elicited lower blood glucose responses as compared to the personalized diet given on the “bad” week.
Before the experiment, a dietitian planned a personal tailored diet for 6 days as follows: each participant decided how many meals and calories he or she eats in a day. All meals in the 6 days were different and in every day the same number of meals and calories were consumed with a gap of at least 3 hours between meals. The content of the meals was decided by the participant to match their taste and regular diet. For example, a participant may choose to eat 5 meal categories a day as following: a 300 calorie breakfast, 200 calorie brunch, 500 calorie launch, 200 calorie snack and 800 calorie dinner. The participant decides on 6 different options for each meal category (5 meal categories in the example: breakfasts, brunch, launch, snack and dinner) with the help of the dietitian to ensure that all breakfasts are isocaloric with a maximum deviation of 10%.
The experiment began with taking a blood sample and anthropometric measurements from the participant, connecting the participant to a continuous glucose monitor and starting the 6 day diet, while logging all eaten meals during the time of the study. On the 7th day of the experiment, the participant performed a standard (50 g) oral glucose tolerance test after which he ate normally throughout that day. The first week which is referred to as the “mix week” exposed the participant to a variety of foods which afterwards determined which meals were relatively “good” and “bad” i.e. which meals resulted in low and high glucose response respectively. The glucose blood levels were monitored using a continuous glucose monitor (Medtronic iPro2) with a high 5 minute temporal resolution. The glucose rise and glucose incremental area under the curve (AUC) was measured for each meal. The meals from low to high response were selected where the best and worst two meals of every meal category were selected and marked as good meals and bad meals.
After the good and bad meals were selected, the participants continued with the additional two weeks of the experiment, which were the test weeks. The “good week” comprised only of good meals and “bad week” comprised only of meals predicted to elicit “bad” (high) blood glucose responses. A week comprised 6 days of diet and one day of 50 grams glucose tolerance test as described above. The order of the weeks was randomly chosen and neither participant nor dietitian were exposed to the order of the weeks. After three weeks, the glucose level between weeks was compared.
To date, 16 individuals completed the experiment out of which 10 had an impaired glycemic response and 6 were healthy.
Results
“Good” and “bad” meals were correctly categorized: It was found that the vast majority of the meals tested in the two test weeks showed a glucose response in accord with the predictions (low/high).
A significant improvement in the average AUC following a meal in the “good” week compared to the “bad” week was observed. This result holds for both healthy and impaired glucose tolerance individuals where in the latter group the differences between the “good” and “bad” week were greater (
The results also showed that blood glucose responses following meals show a diurnal pattern (
Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.
It is the intent of the applicant(s) that all publications, patents and patent applications referred to in this specification are to be incorporated in their entirety by reference into the specification, as if each individual publication, patent or patent application was specifically and individually noted when referenced that it is to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention. To the extent that section headings are used, they should not be construed as necessarily limiting. In addition, any priority document(s) of this application is/are hereby incorporated herein by reference in its/their entirety.
This application is a continuation of U.S. patent application Ser. No. 16/151,455 filed on Oct. 4, 2018, which is a continuation of U.S. patent application Ser. No. 15/030,650 filed on Apr. 20, 2016 which is a National Phase of PCT Patent Application No. PCT/IL2015/050442 having International Filing Date of Apr. 28, 2015, which claims the benefit of priority under 35 USC § 119(e) of U.S. Provisional Patent Application Nos. 61/984,944 filed on Apr. 28, 2014, 62/050,939 filed on Sep. 16, 2014 and 62/048,065 filed on Sep. 9, 2014. The contents of the above applications are all incorporated by reference as if fully set forth herein in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61984944 | Apr 2014 | US | |
| 62050939 | Sep 2014 | US | |
| 62048065 | Sep 2014 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16151455 | Oct 2018 | US |
| Child | 17579638 | US | |
| Parent | 15030650 | Apr 2016 | US |
| Child | 16151455 | US |
