Fetal cardiac growth is associated with in utero gut colonization.

BACKGROUND AND AIMS: Intra-uterine metabolic environment predicts newborns' cardiac morphology, metabolism and future health. In adults, gut microbiota composition relates to altered cardiac structure and metabolism. We investigated the relationship between gut microbiota colonization and fetal cardiac growth. METHODS AND RESULTS: Bacterial composition in meconium samples of 26 healthy, full-term newborns was assessed by 16S rDNA gene sequencing. Its relationship with birth echocardiographic parameters, and the interaction with cord blood levels of inflammatory markers were investigated. Correlative and cluster analysis, linear discriminant analysis effect size and predictive functional analysis based on Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were applied. Fetal left ventricle growth was related to gut microbiota composition at birth. Specifically, left ventricle posterior wall thickness (LVPW) greater than 4 mm was associated with lower microbiota beta and alpha diversity, depletion (LDA score > 3) of several bacteria at each taxonomic level, including Lactobacillales, and enrichment (LDA score > 5) in Enterobacteriales and Enterobacteriaceae. The latter was significantly related to cord blood gamma-glutamyltransferase levels (r = 0.58, p = 0.0057). Functionally, a thicker LVPW was related to up-regulation of pathways involved in lipopolysaccharide biosynthesis (+50%, p = 0.045 in correlative analysis) and energy metabolism (+12%, p = 0.028), and down-regulation of pathways involved in xenobiotic biodegradation (-21 to -53%, p = 0.0063-0.039), PPAR signaling (-24%, p = 0.021) and cardiac muscle contraction (-100%, p = 0.049). CONCLUSION: Fetal cardiac growth and gut colonization are associated. Greater neonatal LVPW thickness is related to lower diversity of the gut microbiota community, depletion of bacteria having anti-remodeling effects, and enrichment in bacteria functionally linked to inflammation.

Role of antral follicle development and cumulus cells on in vitro fertilization of mouse oocytes.

The role exerted by antral follicle development and by companion granulosa cells on the ability of mouse oocytes at metaphase II to fuse with spermatozoa (as estimated by the kinetics of sperm-egg fusion), and to support normal fertilization (estimated by the formation of a male pronucleus) was investigated. After 17 h of culture in vitro, nuclear maturation occurred in 82% of oocytes derived from early antral follicles devoid of granulosa cells (denuded oocytes) and in 95% of oocytes derived from preovulatory follicles and cultured cumulus-intact or cumulus-free. Among the matured oocytes, 95% of cumulus-intact oocytes were arrested at metaphase II, while 61% of denuded and 50% of cumulus-free oocytes were arrested at metaphase I. The competence of denuded and cumulus-free oocytes to override the metaphase I stage was not affected by the addition of preantral granulosa, early antral granulosa or cumulus cells to the maturation medium. The kinetics of sperm-oocyte fusion were comparable in cumulus-intact and cumulus-free oocytes, and were more rapid than those of the early antral oocytes for insemination periods up to 60 min. However, when denuded oocytes were matured in medium containing early antral granulosa or cumulus cells, the kinetics of sperm-egg fusion was greatly accelerated to values equivalent to those of preovulatory oocytes. The ability of denuded oocytes to fuse with spermatozoa was unaffected by the addition of preantral granulosa cells to the maturation medium. Sixty minutes after insemination, the fertilization rates were 39% for denuded oocytes, 50% for cumulus-free oocytes and 73% for cumulus-intact oocytes. The fertilization rate of denuded and cumulus-free oocytes was significantly improved by the addition to the maturation medium of cumulus cells, but not by the addition of preantral or early antral granulosa cells. Taken together, the present results show that in mice, the maturation of both oolemma and ooplasm, required for successful fertilization, is acquired together with the development of antral follicles and is positively affected by cumulus cells during meiotic progression.