Postmenopausal Vaginal Microbiome and Microbiota

Abstract

The ovulatory cycle has a significant influence on the microbial composition, according to the action of estrogen and progesterone on the stratified squamous epithelium, due to an increase in epithelial thickness, glycogen deposition, and influence on local immunology. The 16S rRNA gene amplification and pyrosequencing study demonstrated that healthy women have community state types (CST), classified as; type “L,” with a predominance of Lactobacillus crispatus, type II, with a predominance of Lactobacillus gasseri, type III, where Lactobacillus iners predominates, and type V with a predominance of Lactobacillus jensenii. Type IV does not identify lactobacilli but a heterogeneous population of bacteria. There seems to be a relationship between increased vaginal bacterial diversity and poverty of lactobacilli with the complaining of vaginal dryness. With menopause, there appears to be a reduction in lactobacilli associated with higher serum levels of follicle-stimulating hormone (FSH) and lower estrogen levels. The evaluation of Gram-stained vaginal smears in postmenopause women must take into account the clinical-laboratory correlation. We should observe two meanly possibilities, atrophy with few bacterial morphotypes, without inflammatory, infiltrate (atrophy without inflammation), and atrophy with evident inflammatory infiltrate (atrophy with inflammation or atrophic vaginitis). The relationship between the microbiome and postmenopausal vulvovaginal symptoms seems to be related to the bacterial vaginal population. However, more robust studies are needed to confirm this impression.

Menopausal Changes in the Microbiome—A Review Focused on the Genitourinary Microbiome

“…Humans are host organisms with stable and transient symbiotic microbiota [ 1 ]. A balanced interaction between the host and microbiota is crucial to maintaining host health [ 2 ].…”

“…Menopause is the conclusion of the menstrual cycle in relation to ovarian failure due to reduced estrogen secretion and the loss of progesterone secretion, and with increased life expectancy, the postmenopausal period may account for up to one-third of a woman’s life [ 1 ]. The dramatic changes in a woman’s health after menopause are well-known, and menopause alters the gut microbiota, which has several effects on a woman’s health [ 4 ].…”

“…In the ovulatory cycle, estrogen and progesterone cause thickening of the stratified squamous epithelium of the vagina, deposition of glycogen, and local immunity; therefore, these hormones have substantial effects on the composition of the microbiome [ 5 ]. Alterations in the microbiota due to postmenopausal hormone changes are similar to vaginal dysbiosis observed in inflammatory pelvic disease, human immunodeficiency virus and human papillomavirus (HPV) infections, and pregnancy [ 1 ].…”

Human vaginal microbiota colonization is regulated by female sex hormones in a mouse model

“…Because significant differences were seen in successful initial colonization and duration of colonization between mice within the same treatment group, we considered other factors that could affect the colonization. The transition of women through menopause is marked by a gradual depletion of Lactobacillus species and an increase in anaerobic bacteria (Oliveira et al, 2022). Others have reported that mice given 17β-estradiol are more likely to be colonized by BV associated bacteria (Gilbert et al, 2019).…”

Advanced Technologies for Studying Microbiome–Female Reproductive Tract Interactions: Organoids, Organoids-on-a-Chip, and Beyond

“…90 Low oxygen levels prevalent in reproductive tissues foster stem cell maintenance, while anaerobic or microaerophilic conditions favor the growth of specific reproductive tract microbes. 91 Conversely, changes in local oxygen levels during inflammation and disease may dramatically alter host-microbe dynamics. 92 However, replicating these conditions within organoid models is complex, as the standard oxygen concentration in organoid cultures (around 20%) contrasts sharply with the in vivo reality of less than 5% oxygen.…”