p75 nerve growth factor receptor in the vesical urothelium of patients with neuropathic bladder: An immunohistochemical study

Abstract

Introduction: Nerve growth factor (NGF, apart from its role as a growth factor, appears to be involved in neuroimmune interactions and in tissue inflammation. Low-affinity nerve growth factor receptor (p75 NGFR), if demonstrated in the urothelium, could provide the means for (1) NGF-mediated modulation of the urothelial response to inflammation; (2) NGF-mediated autocrine/paracrine regulation of urothelial proliferation; and (3) p75 NGFR-mediated induction of apoptosis. Objectives: To investigate the presence of p75 NGFR in the vesical urothelium of patients with neuropathic bladder by immunohistochemical methods. Setting: A hospital-based study of consecutive, unselected, adult patients of either sex with neuropathic bladder, undergoing procedure on the urinary tract in a Regional Spinal Injuries Centre located in the north-west of England. Intervention: Cold cup biopsies were taken from the trigone of the neuropathic urinary bladder of 26 patients with neuropathic bladder. Immunohistochemical studies were performed using antiNGF-receptor human monoclonal antibody which reacts with the low affinity receptor (p75 NGFR). Results: Both neural and epithelial structures showed positive immunostaining for p75 NGFR. The basal layer of the transitional epithelium showed strongly positive immunostaining for p75 NGFR in all the 26 cases. The luminal layer of transitional epithelium showed varying degree of positive immunostaining in 12 patients. The nerve fibres showed positive immunostaining for p75 NGFR. In many cases, the positively-stained nerve fibres were coursing very close to the basal layer of the urothelium almost entering the urothelium; however, no NGFR-positive intra-epithelial terminals could be seen. The positively-stained single nerve fibres and positively-stained thicker nerve bundles were seen in abundance in the submucosa but they were present in a sparse manner in the muscularis layer. Conclusion: The presence of p75 NGFR was demonstrated in the urothelium of neuropathic bladder of all the 26 patients with neuropathic bladder. This observation may have potential therapeutic implications.