A Study of Unmyelinated Afferent Axons in the Suburothelium in Women with Urinary Stress Incontinence.

Abstract

Study objectiveTo study the nerve profile of unmyelinated axons beside the suburothelial myofibroblasts, as neuroeffectors, in comparison to the axons in other sites of the suburothelium.MethodsThis is a prospective study. Bladder biopsies were obtained using rigid cystoscopy from four patients with urinary stress incontinence. Suburothelial nerve bundles were studied at two sites: those adjacent to myofibroblasts (Nmyo) and those located within other sites of the suburothelium (Ns). Axonal contents of unmyelinated nerve bundles and Schwann cells within the suburothelium were studied using transmission electron microscopy.ResultsThe mean age of patients was 56 ±15 years. All patients had normal bladder function (maximum cytometric capacity: 554±57 mL). The total of 93 axons beside myofibroblasts and 118 axons in other sites of suburothelium were counted. The mean number of axons per nerve bundle was similar in both groups of nerve bundles (Nmyo: 3.03 vs Ns: 2.95). However, the mean number of large dense cored vesicles (LDCV) and small vesicles (SV) was higher in Nmyo group in comparison to the Ns group imageand imageThe values were (Nmyo:16 vs Ns:12.61) for LDCV and (Nmyo: 1.05 vs Ns: 0.79) for SV. The percentage of activated Schwann cells was higher in Nmyo in comparison to the Ns group (52% vs 32.5%).ConclusionThis study showed that the axonal contents of the nerve bundles adjacent to myofibroblasts had a higher amount of neurotransmitters within them, as compared to nerve bundles elsewhere. This supports the hypothesis that suburothelial myofibroblasts play a role in neuronal signalling.