Maternal Microbial Contributions And Ontogenesis Of The Infant Microbiome In Health And Behavior PDF Download

Over the last decade, myriad scientific discoveries have highlighted the essential role of the gut microbiota during infancy for normal development, including for nutrient extraction and metabolism, maturation of immune competence and neurobehavioral phenotypes. Microbes begin colonizing the gastrointestinal tract rapidly during vaginal delivery and acquisition continues postpartum through exposure to microbes derived from the mother, breastmilk, and the rearing environment. This dissertation utilizes a rhesus monkey ([Macaca mulatta]) model and recent advancements in gene sequencing to gain further insights into the evolved expectation for early exposure to microbes, aiming to elucidate the salience of maternal contributions to the infant's gut microbiome and to improve our understanding of the bidirectional signaling pathways in the gut-brain axis. Through a descriptive examination of the trajectory of microbiota across infancy, we first establish that the bacterial community structure of the infant gut is dynamic, gradually becoming more diverse, with the maturation of microbial community structure influenced by the transition from breastmilk to solid foods. After characterizing the normative patterns of microbial succession, an observational study explored how the maturation of gut microbiota was influenced by maternal care, and was associated with the infant's behavior, and neurodevelopment (as determined by neuroimaging). Commensal taxa were found to vary with consummatory behavior and infant activity levels, but only the variation in the abundance of [Faecalibacterium] was significantly associated with infant temperament and neurodevelopment. Delayed acquisition of microbial community evenness and richness had physiological consequences and was predictive of slower growth trajectories and decreased neural volume at 1 year. Lastly, the early rearing environment was manipulated to investigate the benefits of exposure to the mother and breast milk for gut colonization and infant health outcomes. Cesarean-delivered and formula-fed infants had delayed trajectories of bacterial colonization, which were characterized by lower abundances of commensal taxa and a greater susceptibility to [Campylobacter]-induced diarrheic symptoms. Collectively, these studies further characterized several critical windows of infant development during which the patterns of gut microbial acquisition can impact host physiology, behavioral and brain maturation, and consequently, may have important implications for understanding the role of microbes and a dysbiotic gut in neurodevelopmental disorders.