The effect of milk fat globules on adherence and internalization of Salmonella Enteritidis to HT-29 cells

Changes in Human Milk Fat Globule Composition Throughout Lactation: A Review

There has been a growing interest in understanding how the relative levels of human milk fat globule (MFG) components change over the course of lactation, how they differ between populations, and implications of these changes for the health of the infant. In this article, we describe studies published over the last 30 years which have investigated components of the MFG in term milk, focusing on changes over the course of lactation and highlighting infant and maternal factors that may influence these changes. We then consider how the potential health benefits of some of the milk fat globule membrane (MFGM) components and derived ingredients relate to compositional and functional aspects and how these change throughout lactation. The results show that the concentrations of phospholipids, gangliosides, cholesterol, fatty acids and proteins vary throughout lactation, and such changes are likely to reflect the changing requirements of the growing infant. There is a lack of consistent trends for changes in phospholipids and gangliosides across lactation which may reflect different methodological approaches. Other factors such as maternal diet and geographical location have been shown to influence human MFGM composition. The majority of research on the health benefits of MFGM have been conducted using MFGM ingredients derived from bovine milk, and using animal models which have clearly demonstrated the role of the MFGM in supporting cognitive and immune health of infants at different stages of growth and development.

A Double-Blind, Randomized Intervention Study on the Effect of a Whey Protein Concentrate on E. coli-Induced Diarrhea in a Human Infection Model

Infectious diseases are a major cause of morbidity and mortality worldwide. Nutritional interventions may enhance resistance to infectious diseases or help to reduce clinical symptoms. Here, we investigated whether a whey protein concentrate (WPC) could decrease diarrheagenic Escherichia coli-induced changes in reported stool frequency and gastrointestinal complaints in a double-blind, parallel 4-week intervention study. Subjects were randomly assigned to a whey hydrolysate placebo group, a low-dose WPC group or a high-dose WPC group. After 2 weeks of consumption, subjects (n = 121) were orally infected with a high dose of live but attenuated diarrheagenic E. coli (strain E1392/75-2A; 1E10 colony-forming units). Subjects recorded information on stool consistency and the frequency and severity of symptoms in an online diary. The primary outcome parameters were a change in stool frequency (stools per day) and a change in Gastrointestinal Symptom Rating Scale (GSRS) diarrhea score between the first and second days after infection. Neither dose of the whey protein concentrate in the dietary treatment affected the E. coli-induced increase in stool frequency or GSRS diarrhea score compared to placebo treatment. The composition of the microbiota shifted between the start of the study and after two weeks of consumption of the products, but no differences between the intervention groups were observed, possibly due to dietary guidelines that subjects had to adhere to during the study. In conclusion, consumption of the whey protein concentrate by healthy adults did not reduce diarrhea scores in an E. coli infection model compared to a whey hydrolysate placebo control.

A High-Throughput Comparative Proteomics of Milk Fat Globule Membrane Reveals Breed and Lactation Stages Specific Variation in Protein Abundance and Functional Differences Between Milk of Saanen Dairy Goat and Holstein Bovine

Large variations in the bioactivities and composition of milk fat globule membrane (MFGM) proteins were observed between Saanen dairy goat and Holstein bovine at various lactation periods. In the present study, 331, 250, 182, and 248 MFGM proteins were characterized in colostrum and mature milk for the two species by Q-Orbitrap HRMS-based proteomics techniques. KEGG pathway analyses displayed that differentially expressed proteins in colostrum involved in galactose metabolism and an adipogenesis pathway, and the differentially expressed proteins in mature milk associated with lipid metabolism and a PPAR signaling pathway. These results indicated that the types and functions of MFGM proteins in goat and bovine milk were different, and goat milk had a better function of fatty acid metabolism and glucose homeostasis, which can enhance our understanding of MFGM proteins in these two species across different lactation periods, and they provide significant information for the study of lipid metabolism and glycometabolism of goat milk.

Milk phospholipid supplementation mediates colonization resistance of mice against Salmonella infection in association with modification of gut microbiota

Gut microbiota-mediated colonization resistance against enteropathogens is known to be greatly influenced by bioactive food compounds. This work aims to investigate the effects of milk phospholipid (MP) supplementation on the colonization resistance of mice to Salmonella enterica serovar Typhimurium (S. Typhimurium) infection, with the focus mainly on the change of gut microbiota. Comparative microbiota analysis based on 16S rRNA gene sequence data of mice under different MP supplementation situations allowed us to identify specific microbiota characteristics associated with the varying degree of susceptibility to S. Typhimurium infection. We found that a moderate dietary intake of MPs (0.05 wt%) significantly increased the relative abundance of Bacteroides spp. (p < 0.05) and the propionate level (p < 0.05) in the mouse colon and enhanced colonization resistance against S. Typhimurium infection, when compared with the un-supplemented S. Typhimurium-infected mice, whereas excessive MP supplementation (0.25 wt%) did not significantly change the level of Bacteroides spp. (p > 0.05) and propionate (p > 0.05) and even enhanced the susceptibility and severity of S. Typhimurium infection. Furthermore, the inhibitory effects of Bacteroides spp. and propionate on S. Typhimurium intestinal colonization were verified in an ex vivo S. Typhimurium-infected 3D colonoid culture system. Our results showed that the supplementation of nutraceuticals may not always be the more the better, particularly under specific pathological conditions, and identification of specific gut microbiota characteristics may have the potential to become an indicator of appropriate supplementation in specific cases.

Milk fat globule membrane: the role of its various components in infant health and development

Breastfeeding confers many benefits to the breast-fed infant which are reflected by better short-term and long-term outcomes as compared to formula-fed infants. Many components of breast milk are likely to contribute to these favorable outcomes, and there has recently been focus on the milk fat globule membrane (MFGM). This fraction is a heterogenous mixture of proteins (many of them glycosylated), phospholipids, sphingolipids, gangliosides, choline, sialic acid and cholesterol which is lacking in infant formula as milk fat (which is also low in these components) is replaced by vegetable oils. Many of these components have been shown to have biological effects, and there is considerable evidence from preclinical studies and clinical trials that providing bovine MFGM results in improved outcomes, in particular with regard to infections and neurodevelopment. Since bovine MFGM is commercially available, it is possible to add it to infant formula. There are, however, considerable variations in composition among commercial sources of bovine MFGM, and as it is not known which of the individual components provide the various bioactivities, it becomes important to critically review studies to date and to delineate the mechanisms behind the activities observed. In this review, we critically examine the preclinical and clinical studies on MFGM and its components in relation to resistance to infections, cognitive development, establishment of gut microbiota and infant metabolism, and discuss possible mechanisms of action.

Sources, Production, and Clinical Treatments of Milk Fat Globule Membrane for Infant Nutrition and Well-Being

Research on milk fat globule membrane (MFGM) is gaining traction. The interest is two-fold; on the one hand, it is a unique trilayer structure with specific secretory function. On the other hand, it is the basis for ingredients with the presence of phospho- and sphingolipids and glycoproteins, which are being used as food ingredients with valuable functionality, in particular, for use as a supplement in infant nutrition. This last application is at the center of this Review, which aims to contribute to understanding MFGM's function in the proper development of immunity, cognition, and intestinal trophism, in addition to other potential effects such as prevention of diseases including cardiovascular disease, impaired bone turnover and inflammation, skin conditions, and infections as well as age-associated cognitive decline and muscle loss. The phospholipid composition of MFGM from bovine milk is quite like human milk and, although there are some differences due to dairy processing, these do not result in a chemical change. The MFGM ingredients, as used to improve the formulation in different clinical studies, have indeed increased the presence of phospholipids, sphingolipids, glycolipids, and glycoproteins with the resulting benefits of different outcomes (especially immune and cognitive outcomes) with no reported adverse effects. Nevertheless, the precise mechanism(s) of action of MFGM remain to be elucidated and further basic investigation is warranted.

Milk Fat Globules Hamper Adhesion of Enterohemorrhagic Escherichia coli to Enterocytes: In Vitro and in Vivo Evidence

Enterohemorrhagic Escherichia coli (EHEC; E. coli) are food-borne agents associated with gastroenteritis, enterocolitis, bloody diarrhea and the hemolytic-uremic syndrome (HUS). Bovine milk glycans have been shown to contain oligosaccharides which are similar to host epithelial cell receptors and can therefore prevent bacterial adhesion. This study aimed to describe interactions between EHEC O157:H7 EDL933 and O26:H11 21765 and milk fat globules (MFGs) in raw milk and raw milk cheese, and the impact of MFGs on EHEC strains adhesion to the intestinal tract in vitro and in vivo. Both EHEC serotypes clearly associated with native bovine MFGs and significantly limited their adhesion to a co-culture of intestinal cells. The presence of MFGs in raw milk cheese had two effects on the adhesion of both EHEC serotypes to the intestinal tracts of streptomycin-treated mice. First, it delayed and reduced EHEC excretion in mouse feces for both strains. Second, the prime implantation site for both EHEC strains was 6 cm more proximal in the intestinal tracts of mice fed with contaminated cheese containing less than 5% of fat than in those fed with contaminated cheese containing 40% of fat. Feeding mice with 40% fat cheese reduced the intestinal surface contaminated with EHEC and may therefore decrease severity of illness.

Invited review: Milk phospholipid vesicles, their colloidal properties, and potential as delivery vehicles for bioactive molecules

The milk fat globule membrane (MFGM) is a unique colloidal assembly of phospholipids and proteins, with numerous potential applications as functional ingredient. The phospholipid components of the MFGM are gaining interest as they are a useful matrix for use as a constituent of delivery systems such as liposomes. Liposomes formulated with milk phospholipids are becoming an alternative to other sources of phospholipids such as soybean or egg yolk. However, incorporation of phospholipids fractionated from the milk fat globule membrane in dairy products requires an in-depth understanding of the functional properties of phospholipids. In particular, it is critical to understand which factors play a role in their stability and bioefficacy as delivery systems. Moreover, chemical and physical modifications of phospholipid liposomes occurring during digestion and the fate of the encapsulated compounds are very important to understand. This review discusses recent findings on the structure and functionality of MFGM, the bioactivity of the phospholipids fraction, their utilization as delivery systems, and their stability through gastrointestinal transit.

Inhibition of Cronobacter sakazakii Adhesion to Caco-2 Cells by Commercial Dairy Powders and Raw Buttermilk

Cronobacter sakazakii is a foodborne pathogen that has been associated with severe infections, mainly in neonates. The binding of this bacterium to host cell surfaces represents the first step in the pathogenesis of disease. An ELISA-based assay has been developed using a polyclonal antiserum against C. sakazakii to determine its adhesion to Caco-2 cells. The antiserum used recognized many of the outer membrane proteins of C. sakazakii. A positive correlation was found between the absorbance values obtained by ELISA and the number of bacteria adhered to cells determined by plate counting. The inhibitory effect on bacterial adhesion to cells observed with some dairy products was concentration-dependent. Commercial buttermilk caused the maximal reduction of the adhesion percentage (33.0 ± 5.07) at the highest concentration assayed (20 mg/mL), followed by butter serum (31.9 ± 5.36), skim milk (30.4 ± 5.07), and raw buttermilk (25.6 ± 3.80). In some cases, significant differences (p < 0.05) were found in the inhibition exerted by the different products evaluated. The results obtained in this study demonstrate that dairy products contain some components with the ability to inhibit the adhesion of C. sakazakii to Caco-2 cells.

Dietary Milk-Fat-Globule Membrane Affects Resistance to Diarrheagenic Escherichia coli in Healthy Adults in a Randomized, Placebo-Controlled, Double-Blind Study

BACKGROUND

The milk-fat-globule membrane (MFGM) contains phospholipids and membrane glycoproteins that have been shown to affect pathogen colonization and gut barrier integrity.

OBJECTIVE

In the present study, we determined whether commercial heat-treated MFGM can increase resistance to diarrheagenic Escherichia coli.

METHODS

A randomized, placebo-controlled, double-blind, 4-wk parallel-intervention study was conducted in healthy adults. Participants were randomly assigned to a milk protein concentrate rich in MFGM [10 g Lacprodan PL-20 (Arla Foods Ingredients Group P/S), twice daily; n = 30; MFGM group) or a control [10 g Miprodan 30 (sodium caseinate), twice daily; n = 28]. After 2 wk, participants were orally challenged with live, attenuated diarrheagenic E. coli (10(10) colony-forming units). Primary outcomes were infection-induced diarrhea and fecal diarrheagenic E. coli excretion. Secondary outcomes were gastrointestinal symptoms [Gastrointestinal Symptom Rating Scale (GSRS)], stool frequency, and stool consistency (Bristol Stool Scale).

RESULTS

Diarrheagenic E. coli resulted in increased fecal output, lower relative fecal dry weight, increased fecal E. coli numbers, and an increase in stool frequency and gastrointestinal complaints at day 1 after challenge. MFGM significantly decreased the E. coli-induced changes in reported stool frequency (1.1 ± 0.1 stools/d in the MFGM group; 1.6 ± 0.2 stools/d in the control group; P = 0.04) and gastrointestinal complaints at day 2 (1.1 ± 0.5 and 2.5 ± 0.6 GSRS scores in the MFGM and control groups, respectively; P = 0.05). MFGM did not affect fecal wet weight and E. coli excretion at day 2 after challenge.

CONCLUSIONS

The attenuated diarrheagenic E. coli strain transiently induced mild symptoms of a food-borne infection, with complete recovery of reported clinical symptoms within 2 d. The present diarrheagenic E. coli challenge trial conducted in healthy adults indicates that a milk concentrate rich in natural, bioactive phospho- and sphingolipids from the MFGM may improve in vivo resistance to diarrheagenic E. coli. This trial was registered at clinicaltrials.gov as NCT01800396.

Antimicrobial lipids: Emerging effector molecules of innate host defense

The antimicrobial properties of host derived lipids have become increasingly recognized and evidence is mounting that antimicrobial lipids (AMLs), like antimicrobial peptides, are effector molecules of the innate immune system and are regulated by its conserved pathways. This review, with primary focus on the human body, provides some background on the biochemistry of lipids, summarizes their biological functions, expands on their antimicrobial properties and site-specific composition, presents modes of synergism with antimicrobial peptides, and highlights the more recent reports on the regulation of AML production as well as bacterial resistance mechanisms. Based on extant data a concept of innate epithelial defense is proposed where epithelial cells, in response to microbial products and proinflammatory cytokines and through activation of conserved innate signaling pathways, increase their lipid uptake and up-regulate transcription of enzymes involved in lipid biosynthesis, and induce transcription of antimicrobial peptides as well as cytokines and chemokines. The subsequently secreted antimicrobial peptides and lipids then attack and eliminate the invader, assisted by or in synergism with other antimicrobial molecules delivered by other defense cells that have been recruited to the site of infection, in most of the cases. This review invites reconsideration of the interpretation of cholesteryl ester accumulation in macrophage lipid droplets in response to infection as a solely proinflammatory event, and proposes a direct antimicrobial role of lipid droplet- associated cholesteryl esters. Finally, for the interested, but new- to- the-field investigator some starting points for the characterization of AMLs are provided. Before it is possible to utilize AMLs for anti-infectious therapeutic and prophylactic approaches, we need to better understand pathogen responses to these lipids and their role in the pathogenesis of chronic infectious disease.

Comparative proteomics of milk fat globule membrane proteins from transgenic cloned cattle

The use of transgenic livestock is providing new methods for obtaining pharmaceutically useful proteins. However, the protein expression profiles of the transgenic animals, including expression of milk fat globule membrane (MFGM) proteins, have not been well characterized. In this study, we compared the MFGM protein expression profile of the colostrum and mature milk from three lines of transgenic cloned (TC) cattle, i.e., expressing recombinant human α-lactalbumin (TC-LA), lactoferrin (TC-LF) or lysozyme (TC-LZ) in the mammary gland, with those from cloned non-transgenic (C) and conventionally bred normal animals (N). We identified 1, 225 proteins in milk MFGM, 166 of which were specifically expressed only in the TC-LA group, 265 only in the TC-LF group, and 184 only in the TC-LZ group. There were 43 proteins expressed only in the transgenic cloned animals, but the concentrations of these proteins were below the detection limit of silver staining. Functional analysis also showed that the 43 proteins had no obvious influence on the bovine mammary gland. Quantitative comparison revealed that MFGM proteins were up- or down-regulated more than twofold in the TC and C groups compared to N group: 126 in colostrum and 77 in mature milk of the TC-LA group; 157 in colostrum and 222 in mature milk of the TC-LF group; 49 in colostrum and 98 in mature milk of the TC-LZ group; 98 in colostrum and 132 in mature milk in the C group. These up- and down-regulated proteins in the transgenic animals were not associated with a particular biological function or pathway, which appears that expression of certain exogenous proteins has no general deleterious effects on the cattle mammary gland.