Alteration of Vaginal Elastin Metabolism in Women With Pelvic Organ Prolapse

OBJECTIVE: To compare elastin metabolism in the vagina of women with and without pelvic organ prolapse and to define the regulation of this process by hormone therapy (HT). METHODS: Eighty-seven histologically confirmed full-thickness vaginal biopsies were procured from study participants at time of surgery. Premenopausal women with no prolapse served as controls. Women with prolapse were divided into three groups: premenopausal, postmenopausal not on HT, and postmenopausal on HT. The epithelium was excised leaving the subepithelium, muscularis, and adventitia for analyses. The elastin precursor, tropoelastin, was measured by immunoblotting and mature elastin protein via a desmosine cross-link radioimmunoassay. Matrix metalloproteinases (MMPs)-2 and -9 were quantitated by gelatin zymography. Data were analyzed using Kruskal-Wallis test and post hoc analysis using the Mann-Whitney U test. RESULTS: Tropoelastin (432%), mature elastin (55%), proMMP-9 (90%), and active MMP-9 (106%) were increased in women with prolapse relative to those in the control group while active MMP-2 (41%) was decreased. Comparison of tropoelastin and mature elastin values obtained from the same women showed them to be independently regulated (r=0.19). Interestingly, the high-est amount of both proteins occurred in postmenopausal patients not on HT. CONCLUSION: Elastin metabolism is altered in the vagina of women with prolapse relative to those in the control group, suggesting that vaginal tissue is rapidly remodeling in response to mechanical stretch. We found that elastin levels are highest in the absence of hormones. (Obstet Gynecol 2010; 115: 953-61)