Numerous scientific evidences have shown the importance of the intestinal microbiome – made up of the microbes (bacteria, viruses, fungi, archites, protozoa…) that reside in our intestines and the interactions between their genes – for people’s physical and mental health. Now, research has proven that during and after delivery, bacteria from the mother’s gut are transferred to the baby’s body, seeding a unique community of beneficial bacteria that help break down food, synthesize vitamins, and help the baby stay healthy. newborn’s immune system learn to recognize pathogens.
Researchers have found a new mode of vertical microbial transmission from mother to child, in which microbes in the maternal gut shared genes with microbes in the infant gut during the perinatal period beginning immediately before the birth of the baby and lasting through the first few weeks. after birth, and that this gene transfer allowed maternal microbial strains to influence the functional capacity of the infant microbiome, in the absence of persistent transmission from the microbial strains themselves.
The results of the work have been published in the journal Cell and provide valuable data on the intestinal colonization dynamics that influence infant development before and after birth. “This is the first study to describe the transfer of mobile genetic elements between maternal and infant microbiomes,” says Ramnik Xavier of the Broad Institute at MIT and Harvard and the study’s lead author. “Our study also, for the first time, integrated the gut microbiome and metabolomic profiles of mothers and infants and discovered links between gut metabolites, bacteria, and breast milk substrates. This research represents a unique perspective on the co-development of infant gut microbiomes and metabolomes under the influence of known maternal and dietary factors.”
Intestinal bacteria and the baby’s immune system
Gut bacteria drive the maturation of the immune system in part through the production of microbial metabolites. The development of children’s gut microbiome follows predictable patterns and begins with the transmission of microbes from the mother at birth. Microbial metabolites are not only involved in the maturation of the infant’s immune system, but also influence early cognitive development.
This research represents a unique perspective on the co-development of infant gut microbiomes and metabolomes under the influence of known maternal and dietary factors.
Xavier and colleagues studied the co-development of microbiomes and metabolomes from late pregnancy to the first year of life using longitudinal multiomic data from a cohort of 70 mother-infant pairs and found that there was cross-species transfer from mother to child. large-scale offspring of mobile genetic elements, frequently involving genes related to diet-related adaptations.
Infant intestinal metabolomes had less diversity than maternal metabolomes, but had hundreds of unique metabolites and associations of microbes and metabolites not found in mothers. The metabolomes and serum cytokine signatures of infants given regular but not extensively hydrolyzed formula milk were different from those of exclusively breastfed infants.
“The infant gut harbored thousands of unique metabolites, many of which were likely modified from breast milk substrates by gut bacteria,” said Tommi Vatanen, co-author of the study with Karolina Jabbar, both from MIT’s Broad Institute and harvard. “Many of these metabolites probably affect the immune system and cognitive development.”
Infant gut metabolomes were less diverse than maternal metabolomes, but still more than 2,500 metabolomic features unique to infants were detected, and numerous infant-specific associations of bacterial species and fecal metabolites, including neurotransmitters and immunomodulators, were also identified.
“We were surprised to find that maternal gut bacteria rarely seen in infants contributed to the structure of the infant gut microbiome,” Xavier said. “We also found evidence that prophages (inactive bacteriophages or viruses residing in bacterial genomes) contribute to the exchange of mobile genetic elements between maternal and infant microbiomes.”
The authors state that the maternal microbiome may shape the infant gut microbiome through horizontal gene transfer, in addition to the classic vertical transmission of strains and species. They admit, however, that the fact of not considering changes in diet and lifestyle between pregnancy and postpartum is a limitation of the study because it may have affected alterations in the microbiome and metabolome, so in future studies aim to further investigate the links between bacteria and metabolites, as well as strain-specific bacterial metabolic output using bacteria isolated in vitro.
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