Significant decrease of extracellular matrix in prostatic urethra of patients with benign prostatic hyperplasia

Abstract

Background: Benign prostatic hyperplasia (BPH) nodules increase urethral resistance, resulting in "pressure" of tissue expansion to the urethra and leads to an increase in outflow resistance, accompanied by characteristic lengthening of the prostatic urethra. The goal of this investigation was to analyze and quantify changes of the histological components in the prostatic urethra of patients with BPH and compare with a control group. Methods: Prostatic urethra tissue samples were obtained from ten patients (age range 63 to 79 years, mean 66) with clinical symptoms of bladder outlet obstruction who had undergone open prostatectomy. The ten control group samples (urethral tissue samples from the transitional zone) were collected from prostates obtained during autopsy of accidental death adults of less than 25 years. The Volumetric density (Vv) of the histological components was determined with stereological methods from 25 random fields per sample using the point-count method with a M-42 grid test system. The quantitative data were analyzed using the Kolmogorov-Smirnov and Mann-Whitney U tests. Results: The Vv (mean ± SD) in the control and BPH groups respectively were: 20.3±0.3 and 17.12±1.1 in the elastic fiber system (p<0.007); and 29.7±1.9 and 25.1±2.4 in the collagen compartment (p<0.03). Smooth muscle cell volume was increased in BPH cases, 49.9±0.4 and 52.3±2.3 (not statistically significant). Conclusion: BPH nodules caused a significant decrease of elastic system fibers and collagen in prostatic urethra.