PLoS ONE (Jan 2016)

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

  • Paria Mirmonsef,
  • Anna L Hotton,
  • Douglas Gilbert,
  • Casey J Gioia,
  • Danijela Maric,
  • Thomas J Hope,
  • Alan L Landay,
  • Gregory T Spear

DOI
https://doi.org/10.1371/journal.pone.0153553
Journal volume & issue
Vol. 11, no. 4
p. e0153553

Abstract

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BACKGROUND:Colonization 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. METHODS:Eighty-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. FINDINGS:Glycogen 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. CONCLUSION:Cell-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.