PARAURETHRAL CONNECTIVE-TISSUE IN STRESS-INCONTINENT WOMEN AFTER MENOPAUSE

Objective. To study whether stress urinary incontinence after menopaus e is correlated to changes in the paraurethral connective tissue ultra structure and metabolism. Methods. Transvaginal biopsies were obtained from the paraurethral connective tissue in stress urinary incontinent women after menopause with and without estrogen replacement therapy, and from comparable controls. All the stress-incontinent women underwe nt urodynamic investigation. In the specimens, collagen concentration, measured as hydroxyproline, and the degree of extractability by pepsi n digestion, were quantified. Proteoglycan composition and concentrati on were analyzed using Alcian Blue precipitation, followed by electrop horetic separation and quantification. Using Northern blots, mRNA leve ls for the collagens I and III, the small proteoglycans decorin and bi glycan, and the large proteoglycan versican, were quantified. Collagen structure was examined with transmission electron microscopy, and the diameters of collagen fibrils were analyzed with an interactive image analysis system (IBAS, Zeiss/Kontron). Results. No significant differ ence in paraurethral connective tissue biochemistry or ultrastructure was registered between women with stress incontinence and controls. Es trogen replacement therapy resulted in a lower collagen concentration both between the controls (p=0.02) and between the incontinent women ( 0.02). In the women with stress incontinence also the extractability b y pepsin digestion was higher in the group with estrogen treatment (p= 0.004), indicating a decrease in cross-linking. The proteoglycan/colla gen ratio was higher in the control group with estrogen treatment comp ared to untreated (p=0.02), but no difference was found between estrog en treated and untreated incontinent women. The median collagen fibril diameter was 15% larger in the incontinent group of women without est rogen therapy compared to the control group and 5% larger when compari ng the incontinent group on estrogen replacement therapy to the corres ponding control group. Conclusion. The extracellular matrix of paraure thral connective tissue in stress urinary incontinent women after meno pause reacted differently to estrogen replacement therapy compared to continent controls. In contrast to incontinent women of fertile age no major changes in collagen metabolism were found in stress urinary inc ontinent women after menopause.