γEpithelial Na+ Channel and the Acid-Sensing Ion Channel 1 expression in the urothelium of patients with neurogenic detrusor overactivity.

OBJECTIVE: To investigate the expression of two types of cation channels such as the γEpithelial Na+ Channel (γENaC) and the Acid-Sensing Ion Channel1 (ASIC1) in the urothelium of controls and in patients affected by neurogenic detrusor overactivity (NDO). In parallel, the urodynamic parameters were collected and correlated to the immunohistochemical (IHC) results. SUBJECTS AND METHODS: Four controls and 12 patients with a clinical diagnosis of NDO and suprasacral spinal cord lesion underwent to urodynamic measurements and cystoscopy. Cold cup biopsies were frozen and processed for immunohistochemistry and western blots. Spearman's correlation coefficient between morphological and urodynamic data was applied. One-way ANOVA followed by Newman-Keuls multiple comparison post-hoc test was applied for western blot results. RESULTS: In the controls, γENaC and ASIC1 were expressed in the urothelium with differences in their cell distribution and intensity. In NDO patients, both markers showed consistent changes either in cell distribution and labeling intensity compared to controls. A significant correlation between the higher intensity of the γENaC expression in urothelium of NDO patients and the lower values of bladder compliance was detected. CONCLUSION: The present findings show important changes in the expression of γENaC and ASIC1 in NDO human urothelium. Of note, while the changes in γENaC might impair the mechanosensory function of urothelium, the increase of the ASIC1 might represent an attempt to compensate excess in local sensitivity.