The present application pertains to the fields of proteomics and bioinformatics. More particularly, the present application relates to diagnosing a status of an oral disease, e.g. periodontitis, at varying levels of severity through the quantification of protein biomarkers.
Gingivitis is a non-destructive form of periodontal disease involving soft tissue inflammation of the gums. Gingivitis typically occurs as a bodily response to bacterial biofilms, or plaques, which have adhered to teeth. In the absence of proper treatment, gingivitis may progress to periodontitis, which represents a destructive form of periodontal disease. Periodontitis may begin with a milder of the disease, which later progresses into severe periodontitis. Periodontitis is always preceded by the onset of gingivitis.
Periodontal diseases are the leading cause of tooth loss in adults. Accordingly, diagnostic tests have been developed to identify the probability of whether an individual has developed periodontitis. Oral-fluid-based point-of-case (POC) diagnostics are commonly used for various diagnostic tests in medicine and more recently are being adapted for the determination of oral diseases (Tabak, 2007, Ann N Y Acad Sci 1098: 7-14). The use of oral fluids for POC diagnostics has been shown to be effective in detecting oral cancer (Li et al., 2004, Clin Cancer Res 10:8442-8450; Zimmerman et al., 2008, Oral Oncol. 44(5):425-9) or HIV infection (Delaney et al., 2006, Aids 20: 1655-1660).
Periodontal diseases are presently diagnosed by evaluating clinical parameters such as pocket depth, bleeding on probing, and radiographs. These parameters have limitations in that they lack the ability to predict future attachment loss, and provide information only on the existence of past disease activity. Furthermore, no clinical parameters have been shown to be predictive for periodontal disease activity (“Clinical risk indicators for periodontal attachment loss,” Journal of Clinical Periodontology 1991: v. 18:117-125”). Diagnostic methods in clinical practice today lack the ability to both detect the onset of inflammation, e.g. non-destructive gingivitis, and to identify the likelihood of developing destructive forms of periodontitis in the future.
Thus, there exists a need in the art for an efficient, accurate, and sensitive oral fluid diagnostic methods that can not only recognize the existence of past oral disease activity, but can also diagnose and assess earlier stages of oral diseases. In the case of periodontitis, oral fluid diagnostic methods should be able to distinguish at least between healthy patients and those that have developed gingivitis, milder forms of periodontitis, and/or more severe forms of periodontitis. This diagnostic method may advantageously include the quantification of particular protein biomarkers which are present in oral fluids. These oral fluids may be non-invasively acquired from a patient as gingival crevicular fluid (GCF) and/or saliva fluid.
Demonstrated herein in an exemplary embodiment is a method for diagnosing the status of periodontitis disease. The method includes providing at least one of a gingival crevicular fluid (GCF) sample and a saliva sample, selecting a set of protein biomarkers for identifying a particular state of periodontitis, and determining the expression levels in the selected set of protein biomarkers to diagnose the status of periodontitis disease.
In an aspect of the method, the set of protein biomarkers is selected for distinguishing between a gingivitis state and a periodontitis state.
In another aspect of the method, the set of protein biomarkers is selected for distinguishing between a periodontal health and a disease state.
In yet another aspect of the method, the set of protein biomarkers is selected for distinguishing between a mild periodontitis state and a severe periodontitis state.
In some aspects of the method, the set of protein biomarkers includes at least one protein selected from the group consisting of haemoglobin chains alpha and beta, carbonic anhydrase 1 (International Protein Index or “IPI” #IPI00980674), and plastin 1.
In another aspect of the method, the set of protein biomarkers includes at least one protein selected from the group consisting of S100-P, transaldolase, S100-A8 (calgranulin-A), myosin-9, Haemoglobin Alpha, and Haemoglobin Beta.
In yet another aspect of the method, the set of protein biomarkers includes at least one protein selected from the group consisting of Alpha-1-acid glycoprotein 1 and 2, matrix metalloproteinase-9, Peptidyl-prolyl cis-trans isomerase A, and Haptoglobin-related protein (IPI00431645.1).
In some aspect of the method, the set of protein biomarkers includes at least one protein selected from the group consisting of NADPH oxidase and Alpha-N-acetylgalactosaminidase.
In an aspect of the method, the set of protein biomarkers includes Alpha-N-acetylgalactosaminidase.
In another aspect of the method, the set of protein biomarkers includes at least one protein selected from the group consisting of Protein S100-A11 (IPI00013895.1), Protein IPI00037070.3, catalase (IPI00465436.4), Choline transporter-like protein 2 derivative (IPI00903245.1), and titin isoform N2-B (IPI00985334.2).
In yet another aspect of the method, the set of protein biomarkers includes two or more biomarkers.
In some aspects of the method, the method further includes providing both the GCF sample and saliva sample, generating a first and second protein profile by analyzing the proteome of a GCF sample and a saliva sample, and determining an overlap region between the first and second protein profiles. The set of protein biomarkers are selected for distinguishing between particular states of periodontitis, including calculating a change in abundance of proteins within the overlap region during different stages of periodontitis and selecting those proteins which are under or over expressed during a single state of periodontitis.
In another aspect of the method, the method further includes generating a protein profile by analyzing the proteome of the at least one oral fluid sample, and clustering the protein profile to determine a set of protein biomarkers.
Demonstrated herein in an exemplary embodiment is a kit for diagnosing the status of periodontitis disease. The kit includes a set of protein biomarkers selected to distinguish between gingivitis and periodontitis.
In an aspect of the kit, the set of protein biomarkers includes at least one protein selected from the group consisting of haemoglobin chains alpha and beta, carbonic anhydrase 1 (International Protein Index or “IPI” #IPI00980674), and plastin-1.
In another aspect of the kit, the kit diagnoses gingivitis or mild periodontitis, and the set of protein biomarkers further includes at least one protein biomarkers from saliva data clusters 1B, 1D, 1A4, and 1A5.
These and other aspects, features and advantages of which the disclosed methods and kits are capable of will be apparent and elucidated from the following description of embodiments of the methods and kits, reference being made to the accompanying drawings, in which
Several embodiments of the methods and kits of the present application will be described in more detail below with reference to the accompanying drawings in order for those skilled in the art to be able to carry out the disclosed methods and kits. The methods and kits may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosed methods and kits to those skilled in the art. The embodiments do not limit the scope of disclosed methods or kits. The embodiments are only limited by the appended patent claims. Furthermore, the terminology used in the detailed description of the particular embodiments illustrated in the accompanying drawings is not intended to be limiting of the disclosed methods or kits.
The present application details methods for diagnosing the status of an oral disease, such as periodontitis. The methods may comprise determining the expression level of a set of biomarkers. The set of protein biomarkers may include one or more protein biomarkers which have been shown to vary in abundance at particular stages of oral disease. Accordingly, the set of protein biomarkers may be identified and quantified in expression in order to distinguish between different states of oral disease.
The methods of the present application demonstrate a role for biomarkers to serve as indicators of periodontitis at varying levels of severity, e.g. gingivitis, mild periodontitis. The work described herein demonstrates that elevated levels of multiple biomarkers can be used as a tool for accurately and rapidly determining the status of an oral disease, for example, periodontitis.
As used herein, the term “periodontal health state” is a threshold criteria based and not simply a vague state of health. Patients with a periodontal health state exhibit <10% sites with G.I. of 1.0 or B.O.P. and no sites with G.I. of 2.0 or 3.0. Additionally, they have no sites with interproximal attachment loss and no sites with ppd>3 mm.
As used herein, the term “gingivitis state” is a threshold criteria based on patients exhibiting generalized gingivitis and is not simply a vague state. Generalized gingivitis is shown in patients exhibiting >30% of sites with G.I. >2.0, no sites with interproximal attachment loss, and no sites with ppd>4 mm.
As used herein, the term “mild periodontitis state” is a threshold criteria based on patients exhibiting mild-moderate periodontitis and is not simply a vague state. Mild-moderate periodontitis is shown in patients exhibiting ppd of 5-7 mm and interproximal CAL of 2-4 mm at >8 teeth).
As used herein, the term “severe periodontics state” is a threshold criteria based on patients exhibiting severe periodontitis and is not simply a vague state. Severe periodontitis is shown in patients exhibiting ppd of >7 mm and an interproximal CAL of >5 mm at >12 teeth.
As used herein, the term “biomarker” means a substance that is measured objectively and evaluated as an indicator of normal biologic processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention.
Provided herein is a method to diagnose a status of an oral disease by a measurement of prognostic protein biomarkers indicative of a select status of the oral disease. In an exemplary embodiment, the oral disease is periodontitis, and the protein biomarkers are indicative of either gingivitis, mild periodontitis, or severe periodontitis.
Through a proteomic analysis of gingival cervical fluid (GCF) and saliva samples taken from patients with varying states of oral disease, protein biomarkers may be identified which are increased or decreased in abundance during distinct phases of periodontitis. At least one protein biomarker may be used, alone or in combination, to distinguish between healthy patients, those suffering from gingivitis, and those suffering from mild or severe periodontitis.
Proteomic analysis may be conducted through a combination of liquid chromatography and mass spectrometry techniques. In particular, the proteome of GCF and Saliva oral liquid samples may be analyzed by Fourier Transform—tandem Mass Spectrometry (FT MS/MS). The FT MS/MS proteomic approach may be applied to GCF and Saliva samples collected from periodontally healthy volunteers, those with gingivitis, those with mild and severe periodontitis, and those with no teeth (edentulous controls), in order to try and elucidate a panel of biomarkers that will distinguish between healthy and diseased oral states. In particular, the FT MS/MS approach may be undertaken to discover novel protein biomarkers capable of distinguishing between periodontal health and disease, between gingivitis and periodontitis, and between mild and severe periodontitis, through the use of non-presumptive proteomic analysis of gingival crevicular fluid (GCF) and stimulated saliva.
The inventors have astonishingly found that the expression of a small set of particular protein biomarkers may be determined to identify gingivitis or mild periodontitis. These protein biomarkers show an enhanced change (either increase or decrease) in abundance during gingivitis/mild disease states of periodontitis, and show little changes during severe states of periodontitis. Additionally, the expression of a small set of particular protein biomarkers may be determined to identify severe periodontitis. These protein biomarkers show an enhanced change (either increase or decrease) in abundance during the severe state of periodontitis, and show little changes during gingivitis and mild states of periodontitis. The set of protein biomarkers for identifying and distinguishing severe gingivitis relative to mild periodontitis or gingivitis.
With reference to
At S102, at least one oral fluid sample is provided. According to one embodiment, the oral disease is periodontitis and at least one of a GCF and Saliva sample are provided. The samples may be non-invasively collected from a patient.
At S104, a protein profile is generated by analyzing the proteome of at least one of GCF and Saliva samples. In another embodiment, the protein profile is discovered using LC FT MS/MS.
At S106, the protein profile is clustered to determine those proteins which are best fit to serve in a set of protein biomarkers. Clustering may be performed using a combination of statistical methods including principle component analysis, gamma statistics, and metric multidimensional scaling (MMDS). In one embodiment, group average link hierarchical clustering is employed to determine the set of protein biomarkers. In another embodiment, complete link hierarchical clustering methods are employed to determine the set of protein biomarkers.
At S108, a set of protein biomarkers is selected for distinguishing between different states of an oral disease. In one embodiment, the oral disease is periodontitis and the set of protein biomarkers are selected for distinguishing between gingivitis and periodontitis. In another embodiment, the oral disease is periodontitis and the set of protein biomarkers are selected for distinguishing between mild periodontitis and severe periodontitis.
At S110, the expression levels of the proteins in the selected set of protein biomarkers are determined to diagnose the status of the oral disease.
According to one aspect of the methods, a method for diagnosing the status of an oral disease comprises providing at least one oral fluid sample, generating a protein profile by analyzing the proteome of the at least one oral fluid sample, clustering the protein profile to determine a set of protein biomarkers, selecting a set of protein biomarkers for distinguishing between particular states of an oral disease, and determining the expression levels in the selected set of protein biomarkers to diagnose the status of the oral disease.
According to yet another aspect of the methods, a method for diagnosing the status of periodontitis disease comprises providing at least one of a gingival crevicular fluid (GCF) and a saliva sample, selecting a set of protein biomarkers for identifying a particular state of periodontitis, and determining the expression levels in the selected set of protein biomarkers to diagnose the status of the oral disease.
In some aspect of the methods, the set of biomarkers is selected by analyzing the proteome of gingival crevicular fluid (GCF) and saliva. Proteomic analysis may include Fourier Transform—tandem Mass Spectrometry (FT MS/MS) analysis of proteins which are identified to be over or under expressed in varying states of periodontitis.
Another aspect of the methods, the biomarkers may include only one, or a combination of particular biomarkers which are useful for the diagnosis of a disease state. The expression levels of one, two, or more protein biomarkers are determined to determine a status of an oral disease. In further aspects, three, four, five, or more biomarkers are determined and used to determine the status of an oral disease.
In various aspects of the methods, the one or more protein biomarkers are selected from the group consisting of haemoglobin chains alpha and beta, carbonic anhydrase 1 (International Protein Index or “IPI” #IPI00980674), and plastin 1. The method according to this aspect may be used to distinguish between a healthy state, gingivitis state, a mild state, and a severe state of periodontitis.
In yet another aspect of the methods, one or more protein biomarkers are selected from the group consisting of S100-P, transaldolase, S100-A8 (calgranulin-A), myosin-9, Haemoglobin Alpha, and Haemoglobin Beta. The method according to this aspect may be used to identify the severe state of periodontitis, and distinguish to the severe state of periodontitis from the milder states, e.g. mild periodontitis and gingivitis.
In some aspects of the disclosed methods, one or more protein biomarkers are selected from the group consisting of Alpha-1-acid glycoprotein 1 and 2, matrix metalloproteinase-9, Peptidyl-prolyl cis-trans isomerase A, and Haptoglobin-related protein (IPI00431645.1). The method according to this aspect may be used to identify the severe state of periodontitis, and distinguish to the severe state of periodontitis from the milder states, e.g. mild periodontitis and gingivitis.
In still another aspect of the methods, protein biomarker Alpha-N-acetylgalactosaminidase is selected for identifying gingivitis or mild periodontitis state, and distinguishing them from a severe periodontitis state.
In a further aspect of the methods, one or more protein biomarkers are selected from NADPH oxidase and Alpha-N-acetylgalactosaminidase for identifying gingivitis or mild periodontitis, and distinguishing them from a severe periodontitis state.
According to some aspects, the method for diagnosing the status of an oral disease further includes providing the GCF and saliva sample, generating a first and second protein profile by analyzing the proteome of a GCF sample and a saliva sample, and determining an overlap region between the first and second protein profiles. The selecting the set of protein biomarkers for distinguishing between particular states of periodontitis may include calculating a change in abundance of proteins within the overlap region during different stages of periodontitis and selecting those proteins which are under or over expressed during a single state of periodontitis.
In yet another aspect, the method for diagnosing a status of an oral disease as disclosed by the previous embodiments is performed by a diagnostic kit. The diagnostic kit comprises a set of protein biomarkers for identifying the status of an oral disease. The kit includes the necessary reagents to carry out the assays of the disclosed methods.
While the present application has been described in terms of various embodiments and examples, it is understood that variations or improvements will occur to those skilled in the art. Therefore, only such limitations as appear in the claims should be placed on the disclosed embodiments.
The proteome of gingival crevicular fluid (GCF) and saliva was analyzed to identify biomarkers for different oral disease states, e.g. gingivitis, mild periodontitis, and severe periodontitis. GCF and saliva samples were collected non-invasively from the mouths of several patients. Liquid chromatography techniques coupled with Fourier Transform—tandem Mass Spectrometry (FT MS/MS) were used to separate protein biomarkers from within the samples and to identify the protein biomarkers.
The FT MS/MS proteomic approach was applied to samples collected from periodontally healthy volunteers, those with gingivitis, those with mild and severe periodontitis, and those with no teeth (edentulous controls), in order to try and elucidate a panel of biomarkers that will distinguish between healthy and diseased oral states. In particular, the FTMS/MS approach was undertaken to discover novel protein biomarkers capable of:
1. distinguishing between periodontal health and disease
2. distinguishing between gingivitis and periodontitis
3. distinguishing between mild and severe periodontitis
by non-presumptive proteomic analysis of gingival crevicular fluid (GCF) and stimulated saliva.
Five groups of patient volunteers were recruited as defined in TABLE 1. The study was performed as a cross-sectional study with no interventions planned other than routine therapy that may be clinically indicated. Only 1 visit was required at baseline for sampling, but those in Group 3 and 4 required routine periodontal scaling, root surface debridement and prophylaxis and were therefore re-examined and sampled 3-months following completion of their therapy. Longitudinal analysis was therefore available for groups 3 and 4. The clinical assessments were carried out by a trained study dental surgeon.
Sample Collection
Volunteers were asked to provide 6 samples of GCF collected from the gingival (gum) margin, non-invasively on standard filter papers strips (Periopapers™). They were also asked to provide a stimulated saliva sample by rolling a sterile marble around their mouths for five minutes and expectorating into a graduated sterile glass collection vile for volume measurement.
GCF and saliva were collected from 10 volunteers in each of five clearly defined phenotypic groups: healthy, gingivitis, mild periodontitis, severe periodontitis, and edentulous patients as a -ve control group. A total of 50 patients were therefore recruited and sampled. Volunteers with periodontitis (Groups 3 & 4) were then treated non-surgically in order to remove the periodontal inflammation and restore improved health. GCF and saliva were also collected 3 months post-treatment in these two groups, providing longitudinal data.
Table 2 presents the mean clinical data at a time of baseline and post-therapy obtained from 50 patients representing five phenotypic groups. GCF and Saliva samples were collected from 10 volunteers in each of five clearly defined phenotypic groups: Group I (healthy), Group II (gingivitis), Group III (mild periodontitis), Group IV (severe periodontitis), Group V (edentulous patients as a negative control group), where the phenotypic groups are defined based on predefined clinical data thresholds. Volunteers with periodontitis (Groups 3 & 4) were treated non-surgically in order to remove the periodontal inflammation and restore improved health, and therefore have both “baseline” and “review” clinical data.
GFC Samples
GCF samples were collected on periopaper strips from the mesio-buccal sites of six teeth per volunteer, for 30 seconds as is convention and volumes read on a Perotron 8000™ (Chapple et at 1999). These were placed in 400 μL of a 100 mM ammonium bicarbonate buffer in 1.5 mL screw top cryo-tubes. The GCF samples were immediately frozen to −80° C. Prior to analysis GCF was defrosted on ice. The tubes were vortexed for 30 seconds and the solution removed into a clean snaptop eppendorf tube. 200 μL of ammonium bicarbonate (100 mM) was added to the strips. These were re-vortexed for 30 seconds and re-centrifuged at 13,000 RPM for five minutes. The solution was removed and added to the previous. From each sample within a group 150 μL was combined to give a single “pooled” sample per group. Individual patient samples were held back to allow a post-study re-evaluation at a patient-specific level once the preferred biomarker panels had been elucidated. Therefore 6×1.5 mL “population” samples were available for proteomic analysis by MS as indicated in Table 3.
Saliva Samples
Saliva production was stimulated using a sterile marble and collected for five minutes into 15 mL Falcon tubes. Tubes were frozen at −80° C. Prior to analysis the saliva was defrosted at 4° C. Additional falcon tubes were weighed prior to defrost to transfer the clarified saliva to. Once defrosted the saliva was aliquoted into 1.5 mL snaptop eppendorf tubes and centrifuged at 13,000 rpm for five minutes. The supernatant was transferred into the pre-weighed tubes. The debris pellet was also retained for potential future analysis. Both the weight and volume of saliva was recorded. 10.5 μL of each saliva sample per group was combined in the same manner as GCF samples. However, unlike GCF, saliva was available from the edentulous patient group (Group 5), therefore a total of 7×105 μL “population” saliva samples resulted. As for GCF the individual patient samples were held back to allow future “patient-level” analysis. The Pooled saliva samples were centrifuged at 13,000 RPM for five minutes and 100 μL retained. This was to ensure no debris was transferred into the final sample. Ammonium bicarbonate (100 μL , 200 mM) was added to each sample.
Dithiothrietol was added (20 μL , 50 mM) to both GCF and saliva samples, which were incubated with shaking at 60° C. for 45 minutes to reduce any disulphide bonds. The samples were returned to room temperature prior to addition of iodoacetamide (100 μL , 22 mM) and incubation at room temperature in the dark for 25 minutes. Iodoacetamide alkylates free thiol group on cysteine residues. Dithiothrietol (2.8 μL , 50 mM) was added to quench any remaining iodoacetamide. 1 μg of Lys-C (cleaves proteins at the C terminus of lysine residues) was added to each sample (1:100 enzyme:protein) and incubated at 37° C. with shaking for four hours. 2 μg of trypsin (cleaves proteins at the C terminus of lysine and arginine residues) was added and the digest continued over night at 37° C.
The samples were vacuum centrifuged dry prior to desalting (required for iTRAQ labelling). The samples were acidified (200 μL, 0.5% TFA) and desalting was performed using a Macrotrap (Michrom). The trap was wetted with acetonitrile (3×50%, 200 μL) followed by washing with trifluoroacetic acid (3×0.1%, 200 μL). The sample was then loaded through the trap and the elutant passed through the trap again. The trap was washed again with trifluoroacetic acid (3×0.1%, 200 μL), finally the peptides were eluted with acetonitrile (70%, 100 μL). The samples were vacuum centrifuged dry.
The dry samples were labeled with the iTRAQ 8-plex labels as shown in Table 4 below. The labeling allows all samples to be subsequently mixed together and run under one set of conditions in triplicate. Subsequently the individual group samples were identified from the iTRAQ labels.
The samples were incubated with the labels for two hours at room temperature before all individual samples were mixed together for GCF and Saliva respectively. The combined samples (1 pooled saliva and 1 pooled GCF) were vacuum centrifuged dry. The samples were re-suspended in 100 μL of mobile phase A for the SCX system (10 mM KH2PO4, pH 3, 20% MeCN). The peptides were separated using strong cation exchange chromatography using the above mobile phase A and mobile phase B (10 mM KH2PO4, 500 mM KCl, pH 3, 20% MeCN). The gradient ran for 90 minutes. 15 fractions were collected. Fractions 15 and 12 were combined as were 13 and 14 to give 13 fractions.
With reference to
Fraction Analysis
Each fraction was analysed in triplicate by LC-MS/MS. Peptides were loaded onto a 150 mm Acclaim PepMap100 C18 column in mobile phase A (0.1% formic acid). Peptides were separated over a linear gradient from 3.2% to 44% mobile phase B (acetonitrile+0.1% formic acid) with a flow rate of 350n1/min. The column was then washed with 90% mobile phase B before re-equilibrating at 3.2% mobile phase B. The column oven was heated to 35° C. The LC system was coupled to an Advion Triversa Nanomate (Advion, Ithaca, N.Y.) which infused the peptides with a spray voltage of 1.7 kV. Peptides were infused directly into the LTQ-Orbitrap Velos ETD (Thermo Fischer Scientific, Bremen, Germany). The mass spectrometer performed a full FT-MS scan (m/z 380-1600) and subsequent collision induced dissociation (CID) MS/MS scans of the three most abundant ions followed by higher energy collisional dissociation (HCD) of the same three ions. The CID spectra were used to identify the peptides and the HCD spectra were used to quantify them.
Data analysis
The data were analyzed using Proteome Discoverer (V1.2, Thermo Fisher Scientific). Data were analyzed as the technical repeats. The Mascot and SEQUEST algorithms were used to search the data with identical setting used. The database was the IPI human database supplemented with oral bacteria as described by Socransky. This database was concatenated with a reverse version to provide false discovery rates. The data were searched with the following settings: semi-trypsin was selected as the enzyme with a maximum of 2 missed cleavages, 5 ppm mass accuracy for the precursor ion, fragment ion mass tolerance was set to 0.5 Da. Carboxyamidomethylation of cysteine and iTRAQ addition to the N-terminus and lysine residues were set as a static modification. Phosphorylation of serine, threonine and tyrosine was set as a variable modification as was oxidation of methionine and iTRAQ addition to tyrosine.
The search results from each of the technical replicates were combined and proteins which were identified with two or more peptides were classed as identified. Only unique peptides were used for protein quantification and protein grouping was employed (only proteins which contained unique peptides were used).
From the analysis of all GCF samples, 270 proteins were identified with two or more peptides. This included 264 human proteins and 6 bacterial proteins. The identified proteins are shown along with relative quantification values in the Appendix, Supplemental Table 1. All proteins show ratios relative to the Healthy control group (label 113—health). This data was subsequently normalized to collected GCF volumes and also log transformed (base 2) to give positive and negative abundance values.
There were no proteins which were solely identified in any of the disease states. The majority of the proteins showed a decrease in abundance between health, gingivitis and disease (229 proteins were lower abundance in gingivitis compared to health, 195 in mild periodontitis and 174 in severe periodontitis). This decrease in abundance across the groups may be due to an increase in GCF volume as tissues become more inflamed and as evidenced in Table 2. Alternatively, a “non-normalized” analysis of GCF may be performed to address this issue, which is recognized in the literature (Lamster et at 1986, Chapple et at 1994 & 1999).
Discovered proteins were clustered using the PolySNAP 3 software. PolySNAP 3 compares each 1 dimensional protein profile with every other and uses a weighted mean of Pearson parametric and Spearman nonparametric correlation coefficients to produce similarity scores. The profiles were clustered using a combination of statistical methods including principle component analysis, gamma statistics, and metric multidimensional scaling (MMDS). The data were then visualized in dendrograms, PCA plots, and MMDS plots. In this analysis, the group average link hierarchical clustering and complete link hierarchical clustering methods were used to group the data. In all cases, the number of clusters used was automatically set by PolySNAP3.
From the group average clustering three rounds of clustering were performed. The group with the largest number of proteins was re-clustered at each point.
First Round of Clustering
With reference to
With continuing reference to
The proteins identified clusters of interest, clusters 3, 4, and 5, are shown in the Appendix, Supplementary Table 2.
Second Round of Clustering
With reference to
The proteins identified in clusters of interest, clusters 1C and 1D, are shown in the Appendix, Supplementary Table 3.
Third Round of Clustering
With reference to
The proteins identified in each cluster of interest, 1A3 and 1A4, are shown in the Appendix, Supplementary Table 4.
Final Round of Clustering
With reference to
The multiple rounds of clustering analysis suggest that there are some groups of proteins in GCF which may distinguish between different disease states of periodontitis.
All saliva samples were analyzed similarly to GCF samples. 314 proteins were identified with two or more peptides, including 307 human proteins and 7 bacterial proteins. One protein was identified in only one sample group (edentulous). The identified proteins are shown along with relative quantification values in the Appendix, Supplemental Table 5.
First Round of Clustering
For the clustering analysis the edentulous samples were not included.
Clustering analysis was performed using PolySNAP3. With reference to
The proteins identified in the cluster of interest, cluster 2, is shown in the Appendix, Supplementary Table 6.
Sound Round of Clustering
With reference to
The proteins identified in each cluster of interest, clusters 1B and 1D, are shown in the Appendix, Supplementary Table 7.
Third Round of Clustering
With reference to
The proteins identified in clusters 1A4 and 1A5 are shown in the Appendix, Supplementary Table 8.
With reference to
Final Round of Clustering
With reference to
The proteins observed in the two data sets were compared to identify protein biomarkers that were discovered in both saliva and GCF samples. With reference to
The proteins which are observed in the overlapping region are shown in the Appendix, Supplemental Table 11. The associated abundance data for the proteins in Supplemental Table 11 was collected and subsequently transformed to portray the log (2) ratios for the protein abundance observed. Additionally, two values for the GCF was measured, one normalized to the volume collected, and the other not.
If it is assumed that GCF is a component of saliva, and when saliva is not normalized to the same GCF volumes, it may be of use to compare the three values. Analysis of these triple values shows some of these proteins to have very similar profile. Some of those protein biomarkers with a large increase or decrease in abundance values are depicted in
Gene ontology analysis using The Database for Annotation, Visualization and Integrated Discovery (DAVID) on the GCF and Saliva datasets shows that the most significantly enriched biological process in the saliva dataset were the defense responses, and in GCF dataset, was cytoskeletal organization. The top twenty processes are shown in the Appendix, Supplemental Table 12. Seven of the twenty are enriched in both GCF and saliva including defense responses, responses to stimuli, and glycolysis.
The analysis of GCF and saliva identified 270 proteins in GCF and 314 proteins in saliva of which 95 were identified in both. All proteins except one (solely identified in edentulous saliva) were quantified over the different disease and resolution phases. Of the proteins which are identified in both GCF and saliva there are several proteins which show increases (in both GCF and Saliva datasets) with disease which could potentially be used to distinguish between health, gingivitis, mild and severe periodontitis and resolution of disease.
According to an exemplary embodiment, a method for diagnosing a status of an oral disease includes selecting at least one protein biomarker from the group consisting of: haemoglobin chains alpha and beta, carbonic anhydrase 1 (IPI00980674), and plastin-1. The method may further include diagnosing the status at least one of a healthy state, gingivitis state, and a mild and/or severe periodontitis state. In another embodiment, the at least one protein biomarker is selected from the group consisting of the protein biomarkers in saliva data cluster 1C2 (Supplemental Table 9): Protein #IPI00016347.5, Protein #IPI00377122.4, haemoglobin subunit alpha (IPI00410714.5), haemoglobin subunit delta (IPI00473011.3), haemoglobin subunit beta (IPI00654755.3), protein # IPI00980674.1, and protein accession number #O83773.
There are also several protein biomarkers which are potential indicators for severe periodontitis by showing increases in abundance in both the GCF and saliva datasets. In an exemplary embodiment, a method for diagnosing severe periodontitis includes selecting at least one protein biomarker from the group consisting of: S100-P, transaldolase, S100-A8 (calgranulin-A), myosin-9, haemoglobin alpha, and haemoglobin beta. In another aspect, the method for diagnosing severe periodontitis includes selecting at least one protein biomarker from the group consisting of the protein biomarkers in saliva data cluster 1A1b (Supplemental Table 10): Protein S100-A11 (IPI00013895.1), Protein IPI00037070.3, catalase (IPI00465436.4), Choline transporter-like protein 2 derivative (IPI00903245.1), and titin isoform N2-B (IPI00985334.2).
In yet another aspect, the method for diagnosing severe periodontitis includes selecting at least one protein biomarker from the group consisting of: S100-P, transaldolase, S100-A8 (calgranulin-A), myosin-9, haemoglobin alpha, and haemoglobin beta, alpha-1-acid glycoprotein 1 and 2, matrix metalloproteinase-9, peptidyl-prolyl cis-trans isomerase A and haptoglobin-related protein (IPI00431645.1).
According to another exemplary embodiment, a method for diagnosing gingivitis or mild periodontitis includes selecting at least one protein biomarker from the group consisting of the protein biomarkers in saliva data clusters 1B, 1D (Supplementary Table 7) and/or in saliva data clusters 1A4, 1A5 (Supplementary Table 8). These protein biomarkers all show an increase or decrease in protein abundance between health and gingivitis which is greater in mild periodontitis but less in severe periodontitis. It may be possible to use these to differentiate between gingivitis and mild periodontitis with severe periodontitis.
According to another aspect, a method for diagnosing gingivitis or mild periodontitis includes selecting at least one protein biomarker from NADPH oxidase activator-1 and alpha-N-acetylgalactosaminidase. NADPH oxidase activator-1 is involved in the production of reactive oxygen species. alpha-N-acetylgalactosaminidase portrays has some of the highest ratios for gingivitis and mild periodontitis compared to severe periodontitis. This protein is involved in the breakdown of glycolipids. In another aspect, the method for diagnosing gingivitis or mild periodontitis includes selecting an Alphaa alpha-N-acetylgalactosaminidase biomarker.
gordonii (strain Challis/ATCC 35105/CH1/
sapiens keratin 6E (KRT6E), mRNA
Streptococcus gordonii
Homo sapiens (Fragment)
Treponema pallidum (strain Nichols)
sapiens
pallidum (strain Nichols)
pallidum (strain Nichols)
Treponema pallidum (strain Nichols)
Streptococcus salivarius
Treponema pallidum (strain Nichols)
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/IB2013/058431 | 9/10/2013 | WO | 00 |
Number | Date | Country | |
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61699035 | Sep 2012 | US |