Age-Related Changes, Influencing Factors, and Crosstalk Between Vaginal and Gut Microbiota: A Cross-Sectional Comparative Study of Pre- and Postmenopausal Women.

Objective: The ideal vaginal environment is maintained by Lactobacillus species, which keep the vagina clean and free of infections, boost fertility and immunity. Age-related decline in estrogen affects Lactobacillus population, leading to dominance of nonoptimal species and increased diversity in vaginal microbiota. In this study, we compared the differences between the vaginal microbiota of pre- and postmenopausal women. We also examined the relationships between vaginal and gut microbiota, their relationships with sex hormones and equol-producing ability. Materials and Methods: This was a cross-sectional study of 35 premenopausal and 35 postmenopausal women (age range: 27-76 years). We compared parameters such as the composition of the gut and vaginal microbiota, vaginal pH, estradiol, follicular stimulating hormone, and urinary equol concentration. Results: In the vaginal microbiota of premenopausal women, Lactobacillus species constituted ∼71.98%, and nonoptimal species constituted ∼16.87%. They were 10.08% and 26.78%, respectively, in the vaginal microbiota of postmenopausal women. The proportion of Lactobacillus was significantly low, whereas microbial diversity and vaginal pH were significantly high (p < 0.0001) in postmenopausal women. The compositions of the vaginal microbiota were significantly different in pre- and postmenopausal women. However, such differences were not noticeable in the gut microbiota. Urinary equol production had no significant correlation with vaginal microbiota, although it had significant relationships with gut microbiota in postmenopausal women. In both groups, the proportions of vaginal Lactobacillus were inversely correlated with vaginal microbial diversity and vaginal pH. Conclusion: Postmenopausal women had significantly low Lactobacillus and high nonoptimal species in their vaginal flora, whereas such age-related differences were not identified in gut microbiota. Urinary equol concentration had significant correlation with gut microbiota in postmenopausal women only. This study was registered with the University Hospital Medical Information Network (UMIN) Clinical Trial Registry (Trial registration No.: UMIN000043944).

Characterization of the sugar chain expression of normal term human placental villi using lectin histochemistry combined with immunohistochemistry.

The general sugar expression pattern was studied in 9 normal full-term human placentas by the use of 21 individual lectins in combination with immunohistochemistry for various markers to understand the function of the placenta as the site of feto-maternal interactions. In mature intermediate and terminal villi, the brush border of the syncytiotrophoblast layer strongly expressed GlcNAc (as stained by WGA, S-WGA, DSL lectins) but weakly expressed sialic acid (Mal II, SNA). The cytoplasm of the syncytiotrophoblast layer showed weak expressions of GlcNAc and Gal/GalNAc with granular patterns. The cytotrophoblast layer, as also recognized by PCNA and HAI-1, typically expressed GlcNAc (LEL etc.) and Gal/GalNAc (MAL I). We found that the cytotrophoblast layer became very thin but largely maintained its continuity in the mature villi. The basement membranes of both the trophoblast layer and the endothelial layer strongly and continuously expressed mannose (Con A, LCA) and galactose (ECL, RCA I). Although endothelial cells almost exclusively expressed sialic acid and fucose, UEA I showed a heterogeneous reactivity with endothelial cells within the same vessels. No uniform expression pattern of any sugar was seen in stromal components except for Hofbauer cells, which usually expressed GlcNAc (LEL and DSL etc.). Thus, the sugar expression analysis by lectin histochemistry combined with immunohistochemistry proved helpful to understand the sugar chain related functions of the placenta under both normal and pathological conditions.