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.

Prevalence and risk factors of functional gastrointestinal disorders in Vietnamese infants and young children.

BACKGROUND: Functional gastrointestinal disorders (FGIDs) are common early in life. The prevalence of FGIDs varies among countries but is unknown in Vietnam. The aim of this study is to assess the prevalence of FGIDs in healthy Vietnamese infants and young children. METHODS: This was a cross-sectional, observational study involving healthy infants and young children between 0 - 48 months old in Hanoi, Vietnam. A representative total of 1511 subjects completed the validated questionnaire on paediatric FGIDs. Rome IV criteria were used to define FGIDs. RESULTS: For Vietnamese infants (0-6 months) and young children (7-48 months), the prevalence of having at least one FGID was 10.0% and only 0.6% was having more than one FGID. Infantile regurgitation (9.3%) was the most prevalent FGID among infants 0-6 months of age while all other FGIDs had a low prevalence between 0-2.5%. For young children between 7 - 48 months old, functional constipation was the most common disorder at the rate of 5.6%. Association analysis revealed that the risk of infant regurgitation was significantly lower among infants with exclusively breastfeeding at 2 - 3 months and 3 - 4 months, formula initiation at 0 - 1 months, and higher paternal education level. The prevalence of functional constipation was significantly higher in male subjects, children in families with annual household income between 273,000,000 - 546,999,999 VND (or estimate around 11,800 - 23,800 USD), families with one child only, and formula feeding initiation at 1 - 2 months. CONCLUSIONS: The prevalence of FGIDs in Vietnamese infants and young children is relatively low compared to the published literature using Rome IV diagnostic criteria. Infantile regurgitation was the most common FGID in Vietnamese infants while functional constipation was most prevalent among Vietnamese young children. TRIAL REGISTRATION: Netherlands Trial Registry Identifier: NL7286/NTR7495 .

Bacteroides thetaiotaomicron Fosters the Growth of Butyrate-Producing Anaerostipes caccae in the Presence of Lactose and Total Human Milk Carbohydrates.

The development of infant gut microbiota is strongly influenced by nutrition. Human milk oligosaccharides (HMOSs) in breast milk selectively promote the growth of glycan-degrading microbes, which lays the basis of the microbial network. In this study, we investigated the trophic interaction between Bacteroides thetaiotaomicron and the butyrate-producing Anaerostipes caccae in the presence of early-life carbohydrates. Anaerobic bioreactors were set up to study the monocultures of B. thetaiotaomicron and the co-cultures of B. thetaiotaomicron with A. caccae in minimal media supplemented with lactose or a total human milk carbohydrate fraction. Bacterial growth (qPCR), metabolites (HPLC), and HMOS utilization (LC-ESI-MS2) were monitored. B. thetaiotaomicron displayed potent glycan catabolic capability with differential preference in degrading specific low molecular weight HMOSs, including the neutral trioses (2'-FL and 3-FL), neutral tetraoses (DFL, LNT, LNnT), neutral pentaoses (LNFP I, II, III, V), and acidic trioses (3'-SL and 6'-SL). In contrast, A. caccae was not able to utilize lactose and HMOSs. However, the signature metabolite of A. caccae, butyrate, was detected in co-culture with B. thetaiotaomicron. As such, A. caccae cross-fed on B. thetaiotaomicron-derived monosaccharides, acetate, and d-lactate for growth and concomitant butyrate production. This study provides a proof of concept that B. thetaiotaomicron could drive the butyrogenic metabolic network in the infant gut.

Fifty Percent Human - how art brings us in touch with our microbial cohabitants.

The Human Microbiome, as well as the exploration of the microorganisms inhabiting the human body, are not only integral to the field of microbiology but represent an intrinsic part of all human beings. Consequently, along with scientists, artists have been inspired by the microbiome: transforming it in to tangible artefacts in order to critically question, reflect on and break down the barrier between humans and their microcohabitants. By artistic means, artists help us to understand how microbial research topics are inevitably affected by societal influences, including (health) politics, economics and the arts. Fifty Percent Human is a multidisciplinary artistic research project that aims to reshape our understanding of the human body and its environment as well as to explore possibilities for conscious coexistence in order to bridge the gap between science and society.

Deciphering the trophic interaction between Akkermansia muciniphila and the butyrogenic gut commensal Anaerostipes caccae using a metatranscriptomic approach.

Host glycans are paramount in regulating the symbiotic relationship between humans and their gut bacteria. The constant flux of host-secreted mucin at the mucosal layer creates a steady niche for bacterial colonization. Mucin degradation by keystone species subsequently shapes the microbial community. This study investigated the transcriptional response during mucin-driven trophic interaction between the specialised mucin-degrader Akkermansia muciniphila and a butyrogenic gut commensal Anaerostipes caccae. A. muciniphila monocultures and co-cultures with non-mucolytic A. caccae from the Lachnospiraceae family were grown anaerobically in minimal media supplemented with mucin. We analysed for growth, metabolites (HPLC analysis), microbial composition (quantitative reverse transcription PCR), and transcriptional response (RNA-seq). Mucin degradation by A. muciniphila supported the growth of A. caccae and concomitant butyrate production predominantly via the acetyl-CoA pathway. Differential expression analysis (DESeq 2) showed the presence of A. caccae induced changes in the A. muciniphila transcriptional response with increased expression of mucin degradation genes and reduced expression of ribosomal genes. Two putative operons that encode for uncharacterised proteins and an efflux system, and several two-component systems were also differentially regulated. This indicated A. muciniphila changed its transcriptional regulation in response to A. caccae. This study provides insight to understand the mucin-driven microbial ecology using metatranscriptomics. Our findings show that the expression of mucolytic enzymes by A. muciniphila increases upon the presence of a community member. This could indicate its role as a keystone species that supports the microbial community in the mucosal environment by increasing the availability of mucin sugars.

Microbial Metabolic Networks at the Mucus Layer Lead to Diet-Independent Butyrate and Vitamin B12 Production by Intestinal Symbionts.

Akkermansia muciniphila has evolved to specialize in the degradation and utilization of host mucus, which it may use as the sole source of carbon and nitrogen. Mucus degradation and fermentation by A. muciniphila are known to result in the liberation of oligosaccharides and subsequent production of acetate, which becomes directly available to microorganisms in the vicinity of the intestinal mucosa. Coculturing experiments of Amuciniphila with non-mucus-degrading butyrate-producing bacteria Anaerostipes caccae, Eubacterium hallii, and Faecalibacterium prausnitzii resulted in syntrophic growth and production of butyrate. In addition, we demonstrate that the production of pseudovitamin B12 by E. hallii results in production of propionate by A. muciniphila, which suggests that this syntrophy is indeed bidirectional. These data are proof of concept for syntrophic and other symbiotic microbe-microbe interactions at the intestinal mucosal interface. The observed metabolic interactions between Amuciniphila and butyrogenic bacterial taxa support the existence of colonic vitamin and butyrate production pathways that are dependent on host glycan production and independent of dietary carbohydrates. We infer that the intestinal symbiont A. muciniphila can indirectly stimulate intestinal butyrate levels in the vicinity of the intestinal epithelial cells with potential health benefits to the host.IMPORTANCE The intestinal microbiota is said to be a stable ecosystem where many networks between microorganisms are formed. Here we present a proof of principle study of microbial interaction at the intestinal mucus layer. We show that indigestible oligosaccharide chains within mucus become available for a broad range of intestinal microbes after degradation and liberation of sugars by the species Akkermansia muciniphila This leads to the microbial synthesis of vitamin B12, 1,2-propanediol, propionate, and butyrate, which are beneficial to the microbial ecosystem and host epithelial cells.