Nitric oxide synthase expression in neurogenic bladder disease: a pilot study

Neurogenic bladders are susceptible to bladder cancer development, especially in the case of chronic indwelling catheters. The classic carcinogenesis theory involves the formation of carcinogenic nitrosamines by bacteria due to chronic infection. We designed a pilot study to evaluate the expression of the of Nitric Oxide Synthase (NOS) isoforms in bladder tissue to study the role of the endogenous formation of NO (Nitric Oxide) in neurogenic bladders. Immunohistochemistry was performed on bladder biopsies from neurogenic, normal, and obstructed bladders. The neurogenic bladder had a higher expression of endothelial NOS (eNOS), but especially of neuronal NOS (nNOS). Besides, this extra-neuronal expression of nNOS by urothelium and interstitial cells was observed. This study proves the important role of endogenous formation of NO by suburothelial nerves but also by urothelium and interstitial cells. This overexpression could possibly be a factor in the higher incidence of bladder cancer in neurogenic bladders. On the other hand, it shows the plasticity of the NO pathways in these cases and raises important research questions concerning the physiological role of these changes.