In Vitro and In Vivo Anti-inflammatory Activity of Bovine Milkfat Globule (MFGM)-derived Complex Lipid Fractions

Comprehensive review of milk fat globule membrane proteins across mammals and lactation periods in health and disease

Milk fat globule membrane (MFGM) is a three-layer membrane-like structure encasing natural milk fat globules (MFGs). MFGM holds promise as a nutritional supplement because of the numerous physiological functions of its constituent protein. This review summarizes and compares the differences in MFGM protein composition across various species, including bovines, goats, camels, mares, and donkeys, and different lactation periods, such as colostrum and mature milk, as assessed by techniques such as proteomics and mass spectrometry. We also discuss the health benefits of MFGM proteins throughout life. MFGM proteins promote intestinal development, neurodevelopment, and glucose and lipid metabolism by upregulating tight junction protein expression, brain function-related genes, and glucose and fatty acid biosynthesis processes. We focus on the mechanisms underlying these beneficial effects of MFGM proteins. MFGM proteins activate key substances in in signaling pathways, such as the phosphatidylinositol 3-kinase/protein kinase B, mitogen-activated protein kinase, and myosin light chain kinase signaling pathways. Overall, the consumption of MFGM proteins plays an essential role in conferring health benefits, some of which are important throughout the mammalian life cycle.

Polar lipids modify Alzheimer's Disease pathology by reducing astrocyte pro-inflammatory signaling through platelet-activating factor receptor (PTAFR) modulation

BACKGROUND

Pro-inflammatory processes triggered by the accumulation of extracellular amyloid beta (Aβ) peptides are a well-described pathology in Alzheimer's disease (AD). Activated astrocytes surrounding Aβ plaques contribute to inflammation by secreting proinflammatory factors. While astrocytes may phagocytize Aβ and contribute to Aβ clearance, reactive astrocytes may also increase Aβ production. Therefore, identifying factors that can attenuate astrocyte activation and neuroinflammation and how these factors influence pro-inflammatory pathways is important for developing therapeutic and preventive strategies in AD. Here, we identify the platelet-activating factor receptor (PTAFR) pathway as a key mediator of astrocyte activation. Intriguingly, several polar lipids (PLs) have exhibited anti-inflammatory protective properties outside the central nervous system through their inhibitory effect on the PTAFR pathway. Thus, we additionally investigated whether different PLs also exert inhibitory effects on the PAF pathway in astrocytes and whether their presence influences astrocytic pro-inflammatory signaling and known AD pathologies in vitro.

METHODS

PLs from salmon and yogurt were extracted using novel food-grade techniques and their fatty acid profile was determined using LC/MS. The effect of PLs on parameters such as astrocyte activation and generation of oxygen species (ROS) was assessed. Additionally, effects of the secretome of astrocytes treated with these polar lipids on aged neurons was measured.

RESULTS

We show that PLs obtained from salmon and yogurt lower astrocyte activation, the generation of reactive oxygen species (ROS), and extracellular Aβ accumulation. Cell health of neurons exposed to the secretome of astrocytes treated with salmon-derived PLs and Aβ was less affected than those treated with astrocytes exposed to Aβ only.

CONCLUSION

Our results highlight a novel underlying mechanism, why consuming PL-rich foods such as fish and dairy may reduce the risk of developing dementia and associated disorders.

Milk: A Natural Guardian for the Gut Barrier

The gut barrier plays an important role in health maintenance by preventing the invasion of dietary pathogens and toxins. Disruption of the gut barrier can cause severe intestinal inflammation. As a natural source, milk is enriched with many active constituents that contribute to numerous beneficial functions, including immune regulation. These components collectively serve as a shield for the gut barrier, protecting against various threats such as biological, chemical, mechanical, and immunological threats. This comprehensive review delves into the active ingredients in milk, encompassing casein, α-lactalbumin, β-lactoglobulin, lactoferrin, the milk fat globular membrane, lactose, transforming growth factor, and glycopeptides. The primary focus is to elucidate their impact on the integrity and function of the gut barrier. Furthermore, the implications of different processing methods of dairy products on the gut barrier protection are discussed. In conclusion, this study aimed to underscore the vital role of milk and dairy products in sustaining gut barrier health, potentially contributing to broader perspectives in nutritional sciences and public health.

Resistant Starch from Purple Sweet Potatoes Alleviates Dextran Sulfate Sodium-Induced Colitis through Modulating the Homeostasis of the Gut Microbiota

Ulcerative colitis (UC) is a complicated inflammatory disease with a continually growing incidence. In this study, resistant starch was obtained from purple sweet potato (PSPRS) by the enzymatic isolation method. Then, the structural properties of PSPRS and its protective function in dextran sulfate sodium (DSS)-induced colitis were investigated. The structural characterization results revealed that the crystallinity of PSPRS changed from CA-type to A-type, and the lamellar structure was totally destroyed during enzymatic hydrolysis. Compared to DSS-induced colitis mice, PSPRS administration significantly improved the pathological phenotype and colon inflammation in a dose-dependent manner. ELISA results indicated that DSS-induced colitis mice administered with PSPRS showed higher IL-10 and IgA levels but lower TNF-α, IL-1β, and IL-6 levels. Meanwhile, high doses (300 mg/kg) of PSPRS significantly increased the production of acetate, propionate, and butyrate. 16S rDNA high-throughput sequencing results showed that the ratio of Firmicutes to Bacteroidetes and the potential probiotic bacteria levels were notably increased in the PSPRS treatment group, such as Lactobacillus, Alloprevotella, Lachnospiraceae_NK4A136_group, and Bifidobacterium. Simultaneously, harmful bacteria like Bacteroides, Staphylococcus, and Akkermansia were significantly inhibited by the administration of a high dose of PSPRS (p < 0.05). Therefore, PSPRS has the potential to be a functional food for promoting intestinal health and alleviating UC.

Which is the optimal choice for neonates' formula or breast milk?

The incidence of prematurity has been increasing since the twenty-first century. Premature neonates are extremely vulnerable and require a rich supply of nutrients, including carbohydrates, proteins, docosahexaenoic acid (DHA), arachidonic acid (ARA) and others. Typical breast milk serves as the primary source for infants under six months old to provide these nutrients. However, depending on the individual needs of preterm infants, a more diverse and intricate range of nutrients may be necessary. This paper provides a comprehensive review of the current research progress on the physical and chemical properties, biological activity, function, and structure of breast milk, as well as explores the relationship between the main components of milk globular membrane and infant growth. Additionally, compare the nutritional composition of milk from different mammals and newborn milk powder, providing a comprehensive understanding of the differences in milk composition and detailed reference for meeting daily nutritional needs during lactation.

Structure, Biological Functions, Separation, Properties, and Potential Applications of Milk Fat Globule Membrane (MFGM): A Review

BACKGROUND

The milk fat globule membrane (MFGM) is a thin film that exists within the milk emulsion, suspended on the surface of milk fat globules, and comprises a diverse array of bioactive components. Recent advancements in MFGM research have sparked a growing interest in its biological characteristics and health-related functions. Thorough exploration and utilization of MFGM as a significant bioactive constituent in milk emulsion can profoundly impact human health in a positive manner. Scope and approach: This review comprehensively examines the current progress in understanding the structure, composition, physicochemical properties, methods of separation and purification, and biological activity of MFGM. Additionally, it underscores the vast potential of MFGM in the development of additives and drug delivery systems, with a particular focus on harnessing the surface activity and stability of proteins and phospholipids present on the MFGM for the production of natural emulsifiers and drug encapsulation materials.

KEY FINDINGS AND CONCLUSIONS

MFGM harbors numerous active substances that possess diverse physiological functions, including the promotion of digestion, maintenance of the intestinal mucosal barrier, and facilitation of nerve development. Typically employed as a dietary supplement in infant formula, MFGM's exceptional surface activity has propelled its advancement toward becoming a natural emulsifier or encapsulation material. This surface activity is primarily derived from the amphiphilicity of polar lipids and the stability exhibited by highly glycosylated proteins.

Novel trends and challenges in fat modification of next-generation infant formula: Considering the structure of milk fat globules to improve lipid digestion and metabolism of infants

Differences in the composition and structure of lipid droplets in infant formula (IF) and human milk (HM) can affect the fat digestion of infants, leading to high risk of metabolic diseases during later stages of growth. Recently, interest in simulating HM fat (HMF) has gradually increased due to its beneficial functions for infants. Much research focuses on the simulation of fatty acids and triacylglycerols. Enzymatic combined with new technologies such as carbodiimide coupling immobilization enzymes, solvent-free synthesis, and microbial fermentation can improve the yield of simulated HMF. Furthermore, fat modification in next-generation IF requires attention to the impact on the structure and function of milk fat globules (MFG). This review also summarizes the latest reports on MFG structure simulation, mainly related to the addition method and sequence of membrane components, and other milk processing steps. Although some of the simulated HMF technologies and products have been applied to currently commercially available IF, the cost is still high. Furthermore, understanding the fat decomposition of simulated HMF during digestion and assessing its nutritional effects on infants later in life is also a huge challenge. New process development and more clinical studies are needed to construct and evaluate simulated HMF in the future.

Bioactive Functions of Lipids in the Milk Fat Globule Membrane: A Comprehensive Review

The milk fat globule membrane (MFGM) is a complex tri-layer membrane that wraps droplets of lipids in milk. In recent years, it has attracted widespread attention due to its excellent bioactive functions and nutritional value. MFGM contains a diverse array of bioactive lipids, including cholesterol, phospholipids, and sphingolipids, which play pivotal roles in mediating the bioactivity of the MFGM. We sequentially summarize the main lipid types in the MFGM in this comprehensive review and outline the characterization methods used to employ them. In this comprehensive review, we sequentially describe the types of major lipids found in the MFGM and outline the characterization methods employed to study them. Additionally, we compare the structural disparities among glycerophospholipids, sphingolipids, and gangliosides, while introducing the formation of lipid rafts facilitated by cholesterol. The focus of this review revolves around an extensive evaluation of the current research on lipid isolates from the MFGM, as well as products containing MFGM lipids, with respect to their impact on human health. Notably, we emphasize the clinical trials encompassing a large number of participants. The summarized bioactive functions of MFGM lipids encompass the regulation of human growth and development, influence on intestinal health, inhibition of cholesterol absorption, enhancement of exercise capacity, and anticancer effects. By offering a comprehensive overview, the aim of this review is to provide valuable insights into the diverse biologically active functions exhibited by lipids in the MFGM.

Milk-Fat-Globule-Membrane-Enriched Dairy Milk Compared with a Soy-Lecithin-Enriched Beverage Did Not Adversely Affect Endotoxemia or Biomarkers of Gut Barrier Function and Cardiometabolic Risk in Adults with Metabolic Syndrome: A Randomized Controlled Crossover Trial

Full-fat dairy milk may protect against cardiometabolic disorders, due to the milk fat globule membrane (MFGM), through anti-inflammatory and gut-health-promoting activities. We hypothesized that a MFGM-enriched milk beverage (MEB) would alleviate metabolic endotoxemia in metabolic syndrome (MetS) persons by improving gut barrier function and glucose tolerance. In a randomized crossover trial, MetS persons consumed for two-week period a controlled diet with MEB (2.3 g/d milk phospholipids) or a comparator beverage (COMP) formulated with soy phospholipid and palm/coconut oil. They then provided fasting blood and completed a high-fat/high-carbohydrate test meal challenge for evaluating postprandial metabolism and intestinal permeability. Participants had no adverse effects and achieved high compliance, and there were no between-trial differences in dietary intakes. Compared with COMP, fasting endotoxin, glucose, incretins, and triglyceride were unaffected by MEB. The meal challenge increased postprandial endotoxin, triglyceride, and incretins, but were unaffected by MEB. Insulin sensitivity; fecal calprotectin, myeloperoxidase, and short-chain fatty acids; and small intestinal and colonic permeability were also unaffected by MEB. This short-term study demonstrates that controlled administration of MEB in MetS persons does not affect gut barrier function, glucose tolerance, and other cardiometabolic health biomarkers, which contradicts observational evidence that full-fat milk heightens cardiometabolic risk. Registered at ClinicalTrials.gov (NCT03860584).

Proteomic analysis of milk fat globule membranes from small-sized milk fat globules and their function in promoting lipid droplet fusion in bovine mammary epithelial cells

In mammary epithelial cells, milk fat is synthesized as lipid droplets and secreted in the form of globules. Milk fat globules (MFGs) are covered by a lipid-protein membrane known as the milk fat globule membrane (MFGM). We randomly divided 12 Holstein cows into control and conjugated linoleic acid (CLA) groups. The control group was fed a basal diet, while the CLA group was fed the basal diet + CLA (15 g per kg DM) for 10 days. Cow performance, milk composition, and MFG size were measured daily. On day 10, we extracted MFGM proteins (n = 3) and identified them via quantitative proteomic analysis. We investigated the effects of the MFGM proteins from control and CLA-treated milk on the lipid droplet formation in MAC-T cells. Compared with the control group, the CLA group had reduced milk fat content (3.39 g/100 mL vs. 2.45 g/100 mL) and MFG size parameters (D_[4,3] of 3.85 μm vs. 3.37 μm; D_[3,2] of 3.24 μm vs. 2.83 μm). The specific surface area (SSA) increased in the CLA group. A total of 361 differentially expressed proteins were identified in the CLA group by iTRAQ quantitative proteomic analysis. Among these proteins, 100 were upregulated and 251 were downregulated (p < 0.05). In MAC-T cells, CLA-MFGM proteins increased the diameter of the lipid droplets to 1.32 μm. CLA-MFGM proteins decreased the proportion of the small lipid droplets (15.33% vs. 47.78%) and increased the proportion of the large lipid droplets (25.04% vs. 11.65%). CLA-MFGM proteins promoted lipid droplet fusion. Therefore, MFGM proteins play an important role in the regulation of the lipid droplet size.

Milk polar lipids composition and functionality: a systematic review

Polar lipids including glycerophospholipids and sphingophospholipids are important nutrients and milk is a major source, particularly for infants. This systematic review describes the human and bovine milk polar lipid composition, structural organization, sources for formulation, and physiological functionality. A total of 2840 records were retrieved through Scopus, 378 were included. Bovine milk is a good source of polar lipids, where yield and composition are highly dependent on the choice of dairy streams and processing. In milk, polar lipids are organized in the milk fat globule membrane as a tri-layer encapsulating triglyceride. The overall polar lipid concentration in human milk is dependent on many factors including lactational stage and maternal diet. Here, reasonable ranges were determined where possible. Similar for bovine milk, where differences in milk lipid concentration proved the largest factor determining variation. The role of milk polar lipids in human health has been demonstrated in several areas and critical review indicated that brain, immune and effects on lipid metabolism are best substantiated areas. Moreover, insights related to the milk fat globule membrane structure-function relation as well as superior activity of milk derived polar lipid compared to plant-derived sources are emerging areas of interest regarding future research and food innovations.

The role of orally ingested milk fat globule membrane on intestinal barrier functions evaluated with a suckling rat pup supplementation model and a human enterocyte model

Milk fat globule membrane (MFGM), the membrane surrounding secreted fat droplets in milk, contains components involved in a wide range of bioprocesses including cell proliferation and differentiation. The intestine is relatively immature and permeable at birth. Since MFGM is partly resistant to digestion in infancy, we hypothesized that orally ingested MFGM promotes intestinal development by enhancing intestinal barrier functions in early life. An established suckling rat model was used; Sprague-Dawley rats were bred, and litters were culled to 10 pups/dam. Pups were supplemented orally with MFGM (0, 100, or 300 mg/kg/day) from postnatal day 1 to 20. Intestine samples were collected for histology, qRT-PCR, immunoblotting, and immunohistochemistry analysis. Additionally, differentiated Caco-2 cells were used to assess effects of MFGM on the human intestinal barrier. Control and MFGM-supplemented rat pups showed similar growth. Intestinal differentiation and expression of tight junction proteins in jejunum and colon were significantly increased by orally ingested MFGM, and MFGM supplementation significantly activated PI3K/Akt/mTOR, MAPK, and MLCK signaling pathways, suggesting that MFGM promotes intestinal development by triggering various signaling pathways. In human enterocytes (polarized Caco-2 cells), MFGM (400 µg/mL for 72 h) decreased permeability, as revealed by increased transepithelial electrical resistance. In Caco-2 cells, MFGM also enhanced expression of tight junction proteins, including claudin-4 and ZO-2. In conclusion, orally ingested MFGM may exert beneficial roles in intestinal development by activating various cell signaling pathways to upregulate tight junction proteins and thereby increasing intestinal barrier functions.

Cardiometabolic health benefits of dairy-milk polar lipids

Low-quality dietary patterns impair cardiometabolic health by increasing the risk of obesity-related disorders. Cardiometabolic risk relative to dairy-food consumption continues to be a controversial topic, due to recommendations that endorse low-fat and nonfat dairy foods over full-fat varieties despite accumulated evidence that does not strongly support these recommendations. Controlled human studies and mechanistic preclinical investigations support that full-fat dairy foods decrease cardiometabolic risk by promoting gut health, reducing inflammation, and managing dyslipidemia. These gut- and systemic-level cardiometabolic benefits are attributed, at least in part, to milk polar lipids (MPLs) derived from the phospholipid- and sphingolipid-rich milk fat globule membrane that is of higher abundance in full-fat dairy milk. The controversy surrounding full-fat dairy food consumption is discussed in this review relative to cardiometabolic health and MPL bioactivities that alleviate dyslipidemia, shift gut microbiota composition, and reduce inflammation. This summary, therefore, is expected to advance the understanding of full-fat dairy foods through their MPLs and the need for translational research to establish evidence-based dietary recommendations.