Markers of collagen synthesis and degradation in urogenital tissue from women with and without stress urinary incontinence

Abstract

Multiparity and obesity are risk factors for stress urinary incontinence (SUI), but collagen synthesis and metabolism in the urogenital tissue itself may also affect its function and control of micturition. Whether changes in synthesis or degradation of collagen are part of the etiology of SUI is not known and published studies show diverging results. The aims of the present study was to investigate collagen turnover in urogenital tissue in women with SUI (n=71) and in urologically healthy women (n=31). Markers of collagen synthesis and breakdown, the carboxy-terminal propeptide of type I procollagen (PICP), the carboxy-terminal telopeptide of type I collagen (ICTP), and the amino-terminal propeptide of procollagen III (PIIINP) were assayed in urogenital tissue homogenates and peripheral serum. In the total clinical material SUI patients were significantly older, had a significantly higher body mass index (BMI) and significantly lower serum PICP and tissue ICTP levels than the controls. When healthy controls were compared with SUI patients matched for age, BMI, parity, and hormonal/menopausal status (31 women in each group), the SUI patients had significantly lower serum concentrations of PICP and significantly lower tissue concentrations of PIIINP and ICTP than the controls. Within the total material of SUI patients, post-menopausal women with weak and strong HRT and pre-menopausal women had significantly lower S-ICTP concentrations than untreated post-menopausal patients. Significant negative correlations to parity were found for T-PIIINP and T-PICP and to BMI for T-ICTP. The low tissue collagen marker levels in women with SUI suggest a reduced collagen turnover, which may negatively affect tissue strength and elasticity.