Glycogen Levels in Undiluted Genital Fluid and Their Relationship to Vaginal pH, Estrogen, and Progesterone

Abstract

BackgroundColonization of the female lower genital tract with Lactobacillus provides protection against STIs and adverse pregnancy outcomes. Growth of genital Lactobacillus is postulated to depend on epithelial cell-produced glycogen. However, the amount of cell-free glycogen in genital fluid available for utilization by Lactobacillus is not known.MethodsEighty-five genital fluid samples from 7 pre-menopausal women taken over 4–6 weeks were obtained using the Instead SoftCup® (EvoFem, Inc., San Diego, CA, USA) by consented donors. Cell-free glycogen and glucose in genital fluids and estrogen and progesterone in blood were quantified.FindingsGlycogen ranged from 0.1–32 μg/μl. There were significant differences between women in glycogen over the observation period. There was a strong negative correlation between glycogen and vaginal pH (r = -0.542, p<0.0001). In multivariable analysis, free glycogen levels were significantly negatively associated with both vaginal pH and progesterone (p < 0.001 and p = 0.004, respectively). Estrogen, glucose, age, sexual intercourse 24 hours prior to visit, and days after the initial visit were not significantly associated with free glycogen levels.ConclusionCell-free glycogen concentrations can be very high, up to 3% of genital fluid, and are strongly associated with acidic vaginal pH. However, the fluctuations in glycogen levels in individuals and differences between individuals do not appear to be associated with estrogen.

Chlamydia trachomatis Genital Tract Infections: When Host Immune Response and the Microbiome Collide

“…Several other studies also showed that estrogen contribute to the acidification of the vagina (reviewed in [96]). However, a recent study showed that free glycogen levels, measured in the genital fluids of 7 pre-menopausal women, were negatively associated with pH and progesterone, while estrogen levels had no significant correlation with free glycogen [97].…”

Microbiome in normal and pathological pregnancies: A literature overview

“…Estrogen production varies throughout the menstrual cycle . High estrogen levels lead to the release of glycogen into the vaginal environment, which is broken down into maltose and glucose by alpha‐amylases present in the vaginal mucosa . Lactobacili residing in the lower genital tract use these carbohydrates in a fermentation process to produce lactic acid, thus lowering the pH of the vagina.…”

“…High estrogen levels lead to the release of glycogen into the vaginal environment, which is broken down into maltose and glucose by alpha‐amylases present in the vaginal mucosa . Lactobacili residing in the lower genital tract use these carbohydrates in a fermentation process to produce lactic acid, thus lowering the pH of the vagina. Lactobacili maintain the vaginal pH between 3.5 and 4.5, thereby creating an unfavorable environment for pathogens According to recent studies, vaginal lactobacilli species also produce antibacterial bacteriocins suggesting an additional protective pathway …”

Lactobacilli Dominance and Vaginal pH: Why Is the Human Vaginal Microbiome Unique?

“…Humans experience continuous, 28-day ovarian cycles between menarche and menopause, governed by fluctuations in reproductive steroids. In humans, estrogen levels are closely linked to lactobacilli abundance and vaginal pH, with an increase in estrogen promoting the thickening of the vaginal epithelium and intracellular production of glycogen (Ayre, 1951; Nauth and Haas, 1985; Patton et al, 2000; but see Mirmonsef et al, 2016). Consequently, lactobacilli are most abundant and vaginal pH is lowest when estrogen levels peak just before ovulation (Drake et al, 1980; Wagner and Ottesen, 1982; Eschenbach et al, 2000).…”