Collagen synthesis is not altered in women with stress urinary incontinence.

Abstract

The objective of this study was to demonstrate that weakened pelvic floor support of the lower genitourinary tract in women with stress urinary incontinence (SUI) is due, in part, to decreased collagen synthesis and secretion and/or an altered ratio of collagen III/I synthesis by the fibroblasts of the endopelvic fascia and skin compared to that of women without evidence of pelvic floor weakening. Endopelvic fascia and skin biopsies were obtained from women with SUI (n = 14) and women without evidence of SUI or genital prolapse (n = 12). Fibroblast cultures established from the biopsies were incubated with 3H-proline in medium containing ascorbic acid for 3 hr. Conditioned medium was collected and cells were harvested. The radiolabeled collagens were precipitated and digested with collagenase. The collagen synthesized (as a percent of total protein) was determined. Collagen alpha1(III) was separated from collagen alpha1(I) and alpha2(I) by interrupted SDS-PAGE and the amount of (3)H-proline in each band was determined. Collagen synthesis, expressed as percent of total protein synthesis, was not significantly different between fibroblasts obtained from women with or without SUI. The mean of collagen III/I synthesized in fibroblasts was not significantly different between fibroblasts obtained from women with or without SUI. These data suggest that the lower collagen content in the endopelvic fascia and skin of women with SUI is not due to reduced collagen synthesis or selective reduction in synthesis of either collagen I or collagen III, compared to women without pelvic floor weakening.