Christopher L. Coe, PhD – Slide of the Week

Christopher L. Coe, PhD - Slide of the Week

Title: Maternal Microbiome Changes during Pregnancy

Legend: The diversity and community structure of commensal bacteria in the reproductive and digestive tracts change during pregnancy. In gravid monkeys, the shift in the gut microbiome occurs near term, when the relative abundance of many taxa is lower than in cycling females, and Lactobacillus spp. and one Bifidobacterium increase. This shift may facilitate the transfer of beneficial bacteria during delivery, which  then become established as part of the infant’s microbiome. Oligosaccharides in breast milk can function as prebiotics to enhance the growth of lactobacilli and bifidobacteria.  Amaral, Lubach, Rendina, Phillips, Lyte & Coe (2023) Microorganisms. PMC 10304935

Citation: Amaral, W. Z., Lubach, G. R., Rendina, D. N., Phillips, G. J., Lyte, M., & Coe, C. L. (2023). Significant Microbial Changes Are Evident in the Reproductive Tract of Pregnant Rhesus Monkeys at Mid-Gestation but Their Gut Microbiome Does Not Shift until Late Gestation. Microorganisms, 11(6), 1481.

Abstract: Vaginal and rectal specimens were obtained from cycling, pregnant, and nursing rhesus monkeys to assess pregnancy-related changes in the commensal bacteria in their reproductive and intestinal tracts. Using 16S rRNA gene amplicon sequencing, significant differences were found only in the vagina at mid-gestation, not in the hindgut. To verify the apparent stability in gut bacterial composition at mid-gestation, the experiment was repeated with additional monkeys, and similar results were found with both 16S rRNA gene amplicon and metagenomic sequencing. A follow-up study investigated if bacterial changes in the hindgut might occur later in pregnancy. Gravid females were assessed closer to term and compared to nonpregnant females. By late pregnancy, significant differences in bacterial composition, including an increased abundance of 4 species of Lactobacillus and Bifidobacterium adolescentis, were detected, but without a shift in the overall community structure. Progesterone levels were assessed as a possible hormone mediator of bacterial change. The relative abundance of only some taxa (e.g., Bifidobacteriaceae) were specifically associated with progesterone. In summary, pregnancy changes the microbial profiles in monkeys, but the bacterial diversity in their lower reproductive tract is different from women, and the composition of their intestinal symbionts remains stable until late gestation when several Firmicutes become more prominent.

About the Lab: The Coe Lab’s research program focuses on the relationship between asymmetrical activation patterns of the cerebral cortex and the immune system. These immune studies have been conducted in both healthy human subjects, as well as individuals who experienced unilateral hemispheric damage in the perinatal period or young adulthood. Persistent alterations in the physiological set points for certain immune responses have been found.

Investigator: Christopher L. Coe, PhD

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