P(75) NERVE GROWTH-FACTOR RECEPTOR IN THE VESICAL UROTHELIUM OF PATIENTS WITH NEUROPATHIC BLADDER - AN IMMUNOHISTOCHEMICAL STUDY

Introduction: Nerve growth factor (NGF), apart from its role as a grow th factor, appears to be involved in neuroimmune interactions and in t issue inflammation. Low-affinity nerve growth factor receptor (p(75) N GFR), 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 prolife ration; and (3) p(75) NGFR-mediated induction of apoptosis. Objectives : To investigate the presence of P-75 NGFR in the vesical urothelium o f patients with neuropathic bladder by immunohistochemical methods. Se tting: A hospital-based study of consecutive, unselected, adult patien ts of either sex with neuropathic bladder, undergoing procedure on the urinary tract in a Regional Spinal Injuries Centre located in the nor th-west of England. Intervention: Cold cup biopsies were taken from th e trigone of the neuropathic urinary bladder of 26 patients with neuro pathic bladder. Immunohistochemical studies were performed using antiN GF-receptor human monoclonal antibody which reacts with the low affini ty receptor (p(75) NGFR). Results: Both neural and epithelial structur es showed positive immunostaining for P75 NGFR. The basal layer of the transitional epithelium showed strongly positive immunostaining for P -75 NGFR in all the 26 cases. The luminal layer of transitional epithe lium showed varying degree of positive immunostaining in 12 patients. The nerve fibres showed positive immunostaining for p(75) NGFR, In man y cases, the positively-stained nerve fibres were coursing very close to the basal layer of the urothelium almost entering the urothelium; h owever, 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 p resent in a sparse manner in the muscularis layer. Conclusion: The pre sence of p75 NGFR was demonstrated in the urothelium of neuropathic bl adder of all the 26 patients with neuropathic bladder. This observatio n may have potential therapeutic implications.