Increased and localized accumulation of chondroitin sulphate proteoglycans in the hyperplastic human prostate

OBJECTIVE To analyse by immunohistochemistry the expression of chondroitin sulphate (CS) (detected in the hyperplastic prostate and possibly affecting the proliferation of prostate cells) in benign prostatic hyperplasia (BPH) to determine its distribution and location. MATERIALS AND METHODS Samples of BPH were obtained from 11 patients (aged 58-83 years) and controls consisting of the transitional zone of five prostates from young men aged 19-27 years. Tissue sections were labelled with antibodies against CS, perlecan, type IV collagen, laminin, and smooth muscle cell (SMC) alpha-actin. The amount of CS immunostaining was estimated by semi-quantitative scoring and correlated with prostate-specific antigen (PSA) level and prostate size. RESULTS The anti-CS antibody faintly stained the stroma of normal prostates, but in BPH samples the staining was intense and concentrated around acini, including the periphery of adjacent SMCs. This staining pattern was totally absent in the normal samples. Type IV collagen, perlecan and laminin were homogeneously distributed in the whole stroma of both normal and BPH samples. There was no significant correlation between intensity of CS staining and either PSA or prostate size. CONCLUSIONS The expression of CS proteoglycans is increased in BPH, where they co-locate with basement membranes of the acinar epithelium and of peri-acinar SMCs. This enhanced expression is specific for these proteoglycans, as other basement membrane components are unaffected, and this may result from the regulatory effects of local factors that are active in BPH.