Vaginal Lactobacillus Species and Cytokine Activity in Menopausal Women with OAB

Objectives: Evaluate associations between vaginal Lactobacillus species, vaginal cytokine concentrations, and presence of overactive bladder (OAB) symptoms in postmenopausal women.

Methods: This is a secondary analysis of cervicovaginal lavage (CVL) samples collected at enrollment for a randomized trial of treatment for moderate-severe postmenopausal vaginal discomfort. The baseline questionnaire included questions about urinary frequency and urgency; a positive response to either was used to classify a participant as having OAB. Lactobacillus species were quantified via species-specific qPCR (Qiagen DNeasy UltraClean Microbial Kit) for L iners, L crispatus, and L jensenii, and total bacterial load using the BactiQuant 16S qPCR. Cytokine analysis was performed (ThermoFisher Scientific ProcartaPlex High Sensitivity 9-Plex panel) to measure concentration of IL-1beta, IL-2, IL-4, IL-6, IL-10, IL-12p70, IL-17A, IFN-gamma, and TNF-alpha in samples. We used parametric and non-parametric tests to evaluate for differences in bacteria quantity and cytokine concentration between groups.

Results: Of the 302 women enrolled in the MsFLASH trial, we had complete data for 256 samples. Participants had a mean age ±SD of 61 ±4 years and were primarily white (90.2%), college educated (90.2%), and married (85.2%), and most had not undergone hysterectomy (80%). Half (50.4%) reported OAB symptoms at enrollment. Women with OAB symptoms had significantly higher median total bacterial load (1040.3 copies [OAB] vs 383.6 copies [no OAB], p=0.003)). Quantities of all measured Lactobacillus species were low or undetectable in both groups, but 185 (72.3%) participants had at least one detectable Lactobacillus species. Among the entire cohort, Lactobacillus iners was the most detected species (58.2%) but this did not vary across OAB groups. Women who reported OAB symptoms had higher concentrations of IL-1beta, IL-4, IL-6, IL-12p70, and IFN-gamma while those without OAB symptoms had higher concentrations of IL-2 and TNF-alpha, though none of these differences were statistically significant. IL-10 concentrations were below detectable levels in both groups. IL-17A concentrations were equivalent in both groups.

Conclusions: OAB symptoms were significantly associated with higher total vaginal bacterial quantity in postmenopausal women. Lactobacillus iners was the most commonly detected vaginal Lactobacillus species, but neither detection nor quantity were associated with OAB symptomatology.