The aim of this study was to determine if lysyl oxidase-like 1 (LOXL1) and Fibulin-5 (Fib-5), two crucial proteins in the elastin metabolism pathway, are detectable in the vaginal secretions of women with and without pelvic organ prolapse (POP). We then sought to quantify levels of these proteins in relation to prolapse. Vaginal secretions were obtained from 48 subjects (13 (27.1%) without and 35 (72.9%) with POP-Q Stage 2-4 prolapse). Eleven (22.9%) subjects were premenopausal and 37 (77.1%) were postmenopausal. Presence of LOXL-1 and Fibulin-5 within specimens were first identified via western blotting. Enzyme-Linked Immunosorbent Assays specific for LOXL1 and Fibulin-5 were conducted to quantify total protein secretion. LOXL1 was detected in 45/48 (93.8%) and Fibulin-5 was seen in 24/48 (50%) of subjects. LOXL1 values were lower in women without prolapse (13.3 ng/100 mg median, 24.4 IQR) vs. those with prolapse (26.4 ng/100 mg, 102.2 IQR). On multivariate analysis controlling for age, women with prolapse had a 544% (p=0.0042 higher LOXL1 protein level compared to those without. There was no significant differences in LOXL1 or Fibulin-5 protein detection with relation to menopausal status in bivariate analysis. This is the first published report of non-invasively measuring urogenital LOXL1 and Fibulin-5. In vaginal secretions, LOXL1 protein is higher in subjects with POP than those without.

Endogenous hydrogen sulfide (H₂ S), synthesized by cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE), is a potent vasodilator that can be stimulated by estradiol-17β (E ₂ β) in uterine artery (UA) smooth muscle (UASMC) in vivo; however, the underlying mechanisms are unknown. This study tested a hypothesis that E ₂ β stimulates H ₂ S biosynthesis by upregulating CBS expression via specific estrogen receptor (ER). Treatment with E ₂ β stimulated time- and concentration- dependent CBS and CSE messenger RNA (mRNA) and protein expressions, and H ₂ S production in cultured primary UASMC isolated from late pregnant ewes, which were blocked by ICI 182,780. Treatment with specific ERα or ERβ agonist mimicked these E ₂ β-stimulated responses, which were blocked by specific ERα or ERβ antagonist. Moreover, E ₂ β activated both CBS and CSE promoters and ICI 182,780 blocked the E ₂ β-stimulated responses. Thus, E ₂ β stimulates H ₂ S production by upregulating CBS and CSE expression via specific ER-dependent transcription in UASMC in vitro.