It is well-known that breastfeeding is unequivocally the ideal source for infant nutrition [1-5]. The American Academy of Pediatrics (AAP) recommends breast feeding exclusively for 6 months of life followed by introduction of solid foods with continued breast feeding for at least one year [6]. The 2010 United States Census determined that nearly 70% of mothers work outside of the home [7], resulting in breast feeding mothers needing to routinely express milk during the day, during separation from their infants [8]. Expressed human milk (EHM) is then subsequently packaged in a bottle or bag and refrigerated or frozen for further use [9].
The American Academy of Pediatrics has stated that the supply of infant nutrition is “ . . . a public health issue and not only a lifestyle choice . . . [g]iven the documented short- and long-term medical and neurodevelopmental advantages of breastfeeding.” (AAP) Human milk contains a number of components that are anti-microbial [34]. Heat treatment (i.e. scalding, pasteurization used to prevent lipolysis) can damage membranes surrounding milk fat globules [35]. This fragmentation allows lipases to further degrade triglycerides, thus causing additional alterations in EHM. Therefore, subjecting EHM to heat treatment is detrimental to preserving many of its beneficial, nutritional attributes. While “typical” lipase activity is currently unknown, there is substantial variation in milk triglyceride content, which composes 98% of total lipids in human milk [25]. After only two freeze-thaw cycles, levels of linoleic acid is significantly decreased in addition to (non-significant) decreases in oleate, palmitate, stearate, and myristate after only one freeze-thaw cycle [25].
Moreover, it is well known that early flavor and odor learning can subsequently influence feeding behavior [36](Beauchamp et al. 2009). Additionally, breast milk is a direct reflection of the odors and flavors in a mother's diet [37]. Sweetness and textural properties of breast milk including viscosity and mouth coating vary widely [38]. Infants fed breast milk, milk-based formula, or hydrolyzed casein formula all have differing tolerances and preferences for sweet, bitter, sour, salty and umami as they mature during childhood ([39, 40]. It has been documented that the milk falvor with an elevated FFA level greater than 1.5 mmol L−1 (which include lauric and capric acid), is considered unacceptable by most individuals [41], and may result in infant refusal.
Proper storage of EHM is critical for infant nutrition. It is currently recommended that breast milk must be consumed within 5 hours at room temperature, 5 days under refrigeration (4° C.) or within 5 months of freezing (−20° C.) [10]. Depending on the type and length of storage, EHM may lose some of its functional and nutritional properties [11-14]. Like all mammalian milk, EHM contains lipases that gradually breakdown fatty acids over time. There are two primary EHM lipases: bile salt-dependent lipase (BSDL) and serum-stimulated lipase, also known as lipoprotein lipase (LPL) [15-16]. BSDL has been documented to improve infant lipid digestion and absorption, playing a key role in the breakdown of retinol esters, thereby providing bioavailable vitamin A to the infant [17]. However, unlike BSDL which plays a critical role in the infant gut, LPL has no known function in neonatal digestion. More exactly, it is involved in uptake of circulating fatty acids into the maternal mammary gland [18, 19]. Following consumption, LPL likely degrades upon ingestion due to low pH in the stomach [20].
Excess lipase activity has been implicated in rancidity in mammalian milk [21-23], causing molecular alterations such as an increase in free fatty acids and subsequent rancid off-flavors and odors [24] that are unacceptable to most infants. Lipolysis and subsequent change in odor and flavor profile is a constant issue in the dairy industry, though it is mostly mitigated through the commercial pasteurization process [21, 25], which destroys most lipases. Analogously, mothers with perceived excess lipase in their EHM are encouraged to scald EHM [26], however this is challenging, time-consuming, results in molecular and biochemical, nutritionally-relevant alterations [25, 27, 28] and loss of EHM volume, which are all critical for the infant.
Moreover, mothers face numerous obstacles breast feeding which may lead to early cessation. Insufficient maternity leave [29], overfeeding EHM by caretakers [8, 30, 31], perceived EHM insufficiency [32], and limited public and familial support are all contributing factors to early breast feeding cessation. Travel, challenging pumping conditions and timing can also lead to less than ideal EHM storage situations. Freezing EHM is a common practice for working mothers, since it is considered to be safe and slow the growth of bacteria [33]. However, EHM may develop a rancid flavor after frozen storage as a result of lipolysis and a significant increase in total free fatty acids (FFA), capric acid, and lauric acid [23].
Accordingly, there is a need for a breast milk storage solution that is more robust to environmental stresses, including freezer storage, while retaining desirable flavor and nutritional benefits.
The present disclosure provides methods and apparatus for improving EHM shelf-life as well as maintaining or improving EHM taste and smell comprising the utilization of specific lipase inhibitors and antibodies. In particular, the present disclosure provides methods and apparatus for lipase-reducing interventions.
According to an embodiment the present disclosure provides methods and apparatus for improving EHM shelf-life as well as maintaining or improving EHM taste and smell comprising the utilization of specific lipase inhibitors. In particular, the present disclosure provides methods and apparatus for lipase-reducing interventions. According to a specific embodiment, the present disclosure provides for the addition of lipase-inhibitors and/or antibodies directly to EHM. According to another specific embodiment, the present disclosure provides an EHM storage container that reduces or eliminates some or all of the negative consequences of the presence of lipase in EHM. According to a still further embodiment, the present disclosure provides a device having lipase inhibitors and/or lipase-specific antibodies immobilized to at least a portion of a surface such that EHM that passes over or otherwise contacts the surface is exposed to the lipase inhibitors and/or lipase-specific antibodies.
For the purposes of the present disclosure, the term “lipase inhibitor” is intended to mean a molecule which is able to specifically bind to a lipase of interest (LPL for example), thereby preventing lipolysis.
As discussed above, EHM contains many different lipases, some of which, like BSDL, are known to be beneficial to neonatal health while others, like LPL, have no known benefit to the infant. Accordingly, unlike pasteurization, which destroys all lipases present in EHM, an embodiment of the present disclosure provides for utilization of specific lipase inhibitors and/or antibodies, which can reduce or eliminate the presence or activity of only certain undesirable lipases, or “lipases of interest”. For example, various embodiments may use lipase inhibitors or antibodies that do not have any known positive effect on infant health or only those lipases that are known to have a negative effect on EHM. As a specific example, an embodiment of the present disclosure might utilize lipase inhibitors or antibodies that have been found to be effective against LPS but ineffective against BSDL. Alternatively, or additionally, an embodiment of the present disclosure might utilize lipase inhibitors or antibodies that have been found to be prevent or inhibit fatty acid synthesis, lipolysis, or other activities and/or molecules that are associated with unpleasant flavors, rancidity, or other identified factors. Examples of molecules which may be targeted due to their associate with unpleasant flavors include, but are not limited to, capric acid and lauric acid (See, e.g.,
Suitable lipase inhibitors or lipase specific antibodies include both naturally occurring and synthetic lipases and antibodies. Examples of lipase inhibitors include, but are not limited to, GSK264220A, Orlistat, RHC 80267, and Xen 445. An excellent discussion of lipases and lipase inhibitors is provided in Bialecka-Florjanczyk et al., “Synthetic and Natural Lipase Inhibitors” Mini-Reviews in Medicinal Chemistry, 2018, Vol. 18, No. 8. Examples of suitable antibodies include, but are not limited to, ab137821 (Abc am), MAb 5D2 or any antibody that will bind to and inhibit LPL from degrading lipids into fatty acids.
According to a first embodiment, the present disclosure provides for the addition of lipase inhibitors or lipase-specific antibodies directly to EHM. For example, an amount of lipase inhibitor may be added to a container containing EHM under sufficient conditions that the EHM is able to interact with and thus bind to the lipase inhibitors. For the purposes of the present disclosure, and unless specifically stated to the contrary, the term “container” is intended to include any item that is able to contain EHM either temporarily or for storage, including, but not limited to, bottles, bags, plasticware, glassware, etc.
According to a further embodiment, rather than adding the lipase inhibitors directly to the EHM, the present disclosure provides a container having lipase inhibitors or antibodies immobilized to at least a surface of the container (referred to herein as an anti-lipase coating). In this embodiment, because the lipase inhibitor is immobilized to the surface of the container, any lipase in the EHM that is exposed to the lipase inhibitor will bind to the immobilized lipase inhibitor and thus bound to the container surface as well. The resulting lipase-free EHM can then be fed directly to an infant or transferred to another storage container. It will be understood, or course, that the term “lipase-free” in this context is intended to indicate that at least some of the lipase of interest in the EHM has been bound or altered in such a way that the negative effects of the presence of the lipase of interest on EHM are reduced or eliminated. As stated above, the anti-lipase coating may contain lipase-inhibitors or antibodies that specifically or preferentially inhibit only some lipases.
An exemplary lipase-inhibiting EHM storage bag 10 is shown in
According to a still further embodiment, the lipase-inhibiting coating is applied to at least a portion of a device surface to which the EHM will be directly exposed some time prior to use (i.e. feeding of the EHM to an infant.) Suitable devices include, but are not limited to, any surface of a breast pump which makes direct contact with the EHM, including tubing, suction cups, bags, and/or containers, as well as filters, funnels, tubing, bottles, nipples, or other apparatus that might be used for collection, storage, or delivery of EHM (whether delivery is directly to an infant or to another container). According to this embodiment, the device may be made of any suitable material including, but not limited to plastics and/or glass.
It will be appreciated that the specific mechanism by which the lipase inhibitor is immobilized to the surface will be determined by multiple factors including, but not limited to, the specific lipase inhibitor being immobilized, the material that forms the surface, expected temperature range, and characteristics of that material including, but not limited to, whether the material is rigid (like a bottle) or flexible (like a storage bag). For example, coatings used for storage bags would likely be expected to maintain their ability to immobilize lipase inhibitors in temperatures that are below freezing (for storage) and as high as body temperature (for feeding). Of course, some surfaces may be intended for use at more limited temperature ranges (i.e. surfaces for use with a breast pump may not need to include coatings that are sufficient at freezing temperatures.) It should be further noted that the lipase-inhibiting coating may not successfully immobilize all lipase inhibitors at all times, there my be some release or separation under some conditions, but the general intent would be for the coating to generally retain the lipase of interest during collection, storage and/or delivery of the EHM (again, whether delivery is directly to an infant or to another container).
Suitable polymer coatings may include polyethylene glycol or cholesterol-based or -derived coatings such as, though not limited to, those described in, for example, Tiller et al., Designing surfaces that kill bacteria on contact” PNAS, May 22, 2001 Vol. 98, no. 11, pp 5981-5985; Kim et al., “From Self-Assembled Monolayers to Coatings: Advances in the Synthesis and Nanobio Applications of Polymer Brushes,” Polymers 2015, 7, 1346-1378; and Sidenbiedel et al., “Antimicrobial Polymers in Solution and on Surfaces: Overview and Functional Principles” Polymers 2012, 4, 46-71; as well as U.S. Provisional Patent Application No. 62/779,665, filed Dec. 14, 2018. Of course it will be appreciated that some of the above-described coatings may be better suited for certain applications over others and may, thus, require certain modifications. For example, a coating which is typically used to retain only a certain molecule, only on certain types of surfaces (i.e. rigid), only on certain materials, or only for the short term (i.e. for the purposes of drug delivery) might need to be modified for the present purposes of retention of certain lipases of interest. Accordingly, it will be appreciated that the above-identified list is provided only as general guidance with regards to various types of coatings that could be utilized or modified for the presently described purposes.
It will be appreciated that while the present disclosure has been directed primarily towards expressed human breast milk and the collection and storage thereof, the presently described methods and devices could similarly be applied to other substances including food and food products (including, but not limited to non-human derived milk), particularly, though not necessarily, when such foods or food products are not pasteurized.
The terms and expressions that have been employed are used as terms of description and not of limitation, and there is no intent in the use of such terms and expressions to exclude any equivalent of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention as claimed. Thus, it will be understood that although the present invention has been specifically disclosed by preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims.
All patents and publications referenced below and/or mentioned herein are indicative of the levels of skill of those skilled in the art to which the invention pertains, and each such referenced patent or publication is hereby incorporated by reference to the same extent as if it had been incorporated by reference in its entirety individually or set forth herein in its entirety. Applicants reserve the right to physically incorporate into this specification any and all materials and information from any such cited patents or publications.
LPL activity in milk spiked with 6 pmol LPL and increasing levels of Orlistat (an LPL inhibitor) was monitored over the course of 20 min (
Coating of Commercial Milk Storage Bags with Cholesterol
Sections (2 cm2) of commercial breast milk storage bags (Medela LLC, McHenry, IL) were cut to size (n=3) for coating with cholesterol (a milk/storage bag compatible coating vehicle). Cholesterol (5% w/v) was dissolved into heated ethanol (50° C.). The pre-weighed bag sections were taped to a backing card and coated in a fume hood. Spray coating was performed using a Master Airbrush® System model G22 airbrush apparatus and a compressor (TCP Global, San Diego, Calif.). Each single sweep coating application was followed by 2 minutes solvent evaporation time, this was repeated in triplicate. Cholesterol weight gain over time with bag sections was determined (Table 2). Visual comparison of section of the storage bags showed minimal impact from the cholesterol coating.
The following application claims benefit of U.S. Provisional Application No. 62/607,699, filed Dec. 19, 2017, which is hereby incorporated by reference in its entirety.
Filing Document | Filing Date | Country | Kind |
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PCT/US2018/066477 | 12/19/2018 | WO | 00 |
Number | Date | Country | |
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62607699 | Dec 2017 | US |