Estrogen receptor in pelvic floor tissues in patients with stress urinary incontinence

Our study is to investigate the presence of estrogen receptor (ER) and its possible etiological relationship with the development of stress urinary incontinence (SUI). Thirty-one biopsy specimens from pelvic floor tissues were obtained from 31 patients categorized into three groups: pelvic organ prolapse (POP), SUI and control groups. ER in the pelvic muscles tissues was evaluated quantitatively after immunohistochemical staining to visualize the ER in the tissue. The sampling rate of levator ani (striated) muscle was 6.7% in total sample from the pelvic floor tissues, with the remaining showing connective tissues, smooth muscles and nerve fibers. ER positive staining was found in the in the nuclei of connective tissue, smooth muscles and nerve fibers. The positive rates of ER staining in tissues were 1.4%, 4.7% and 5.7%, respectively in control group versus 1.1%, 2.8% and 2.7% in SUI group and 4.1%, 9.5% and 11.6% in POP group. The positive rates of ER staining in connective tissue, smooth muscle and nerve fibers in SUI group were significantly lower than that in control and POP group (P<0.01). Our study suggests that a decrease of ER in the pelvic floor tissues might be related to the occurrence of SUI and implies that hormone replacement therapy might not be effective in treatment for SUI.