Cellular proliferation in the female lower urinary tract with reference tooestrogen status

Objective To assess cell proliferation throughout the tissues of the female lower urinary tract and to compare cell proliferation rates in women of va rying oestrogen status. Design Prospective observational study. Setting A large teaching hospital. Sample Fifty-nine women undergoing surgery for urogynaecological conditions of whom 23 were premenopausal, 20 were postmenopausal and taking no oestro gen supplementation and 16 were postmenopausal and receiving some form of h ormone replacement therapy. Biopsies were taken during surgery from the bla dder dome, trigone, the proximal and distal urethra, vagina and vesico-vagi nal fascia in the region of the bladder neck. Methods Formalin-fixed paraffin-embedded biopsies were labelled by an avidi n-biotin technique with a monoclonal antibody raised against part of the nu clear matrix known as Ki-67 antigen. Main outcome measures Ki-67 expression was assessed in the epithelial, sube pithelial and muscle or deep fascial regions of all tissues and related to oestrogen status. Results Ki-67 expression was only found in high levels in biopsies containi ng squamous epithelia. Significantly hi-her levels of Ki-67 expression were observed in the tissues of oestrogen replete women in the premeno pausal a nd hormone replacement groups, compared with postmenopausal women receiving no oestrogen supplementation. Conclusions Squamous epithelia of the female lower urinary tract exhibit gr eater levels of cell proliferation in oestrogen replete as compared with oe strogen deficient women. As these same squamous epithelia also consistently express oestrocren receptors, the findings suggest a mechanism by which oe strogen exerts its effect on the lower urinary tract and also provide an ex planation for the success of oestrogen in the treatment of some conditions causing lower urinary tract dysfunction in postmenopausal women.