Focal changes in nerve, muscle and connective tissue in normal and unstable human bladder

Objective To compare and quantify, in a morphological study, the changes th at occur in the connective tissue elements (elastin and collagen), muscle f ibre diameters and nerve densities between normal, idiopathic and neuropath ic bladders. Materials and methods Bladder tissue was obtained from 27 patients undergoi ng cystectomy for carcinoma, from 12 with idiopathic instability and from s even neuropathic patients who were undergoing ileocystoplasty. A combinatio n of histochemical and immunohistochemical techniques were used to detect d etrusor muscle, connective tissue and nerve profiles in the bladder tissue. Results In both idiopathic and neuropathic bladder tissue the structural ch anges were highly punctate. From the density of nerve profiles, three areas were defined: (i) apparently unaffected normal fascicles with a high densi ty of nerves, no hypertrophy of the muscle and no infiltration of elastin a nd collagen. The nerve density in these areas was similar to that in normal bladder tissue. (ii) Fascicles with a low density of nerve profiles, muscl e hypertrophy but no connective tissue infiltration. (iii) Areas with few n erve profiles, muscle hypertrophy and extensive elastin and collagen infilt ration within the fascicles. The mean (sem) density of nerve profiles in co ntrol tissue was 752 (53) nerves/mm(2) and in the idiopathic bladders was 9 05 (91), 81 (20) and 74 (38) nerves/mm(2) in the three defined areas, respe ctively. In the neuropathic tissues the nerve profile densities were 672 (2 49), 57 (23) and 37 (28) nerves/mm(2) , respectively. Fibre diameter, elast in and collagen content and nerve density were measured in normal and unsta ble bladder tissue using these three defined areas. The mean (sem) fibre di ameter was 6.81 (0.52) in normal bladder; in idiopathic bladder tissue the fibre diameters in the three areas were 6.72 (0.62), 7.06 (0.62) and 7.34 ( 1.15) mu m, respectively, and in neuropathic bladders were 6.75 (0.62), 8.2 4 (0.62) and 9.35 (0.62) mu m, respectively. The relative areas of elastin were 0.79 (0.70), 0.56 (0.45) and 18.3 (4.1)% for the control, normal and a ffected areas of the neuropathic bladders, respectively, and the relative a reas of collagen were 3.5 (1.3), 6.15 (3.6) and 15.7 (5.0)%, respectively. The pattern was similar in idiopathic bladders. Conclusion These observations suggest that the primary defect in the idiopa thic and neuropathic bladders is a loss of nerves accompanied by a hypertro phy of the cells. These changes may continue with further hypertrophy of th e cells and an increased production of elastin and collagen within the musc le fascicles.