Characteristics of separated epithelial and stromal subfractions of prostate: II. Human prostate

Surgical samples of human benign prostatic hyperplasia tissue (BPH) were fractionated into epithelial clumps and stromal fractions, using the "optimal" tissue dissociation procedure developed for rat prostate described in the preceding report. The separated cellular fractions were compared to control unfractionated tissue (wherein extracellular secretory products had been removed) with respect to the concentrations of androgen receptor and enzyme markers on a DNA basis; cell damage was also evaluated by light and electron microscopy (EM). EM revealed extensive cell damage in epithelial clumps and stromal fractions, which had appeared normal when examined by light microscopy. Damage to the ultrastructure of individual epithelial cells present in clump fractions was very variable, involving vacuolization of the cytoplasm and condensation of nuclear chromatin in some cells, vacuolization of just the cytoplasm in other cells; only a small fraction of the cells in clumps had normal ultrastructure. Ultrastructural damage to stromal cells was much greater in fibroblasts than in muscle fibers. The cell damage observed in both subfractions of human prostate was associated with a marked degree of receptor loss. The mean decreases in the number of androgen receptors per unit DNA relative to control unfractionated tissue was 68.5 and 62.5% recovered in epithelial and stromal fractions, respectively. Measurement of various enzymes as "markers" revealed that acid phosphatase activity (per unit DNA) was associated exclusively with the epithelial clump fraction. Prolyl hydroxylase and myosin ATPase activities (per unit DNA) were restricted to the stromal fraction. The limitations of using mechanically separated subfractions of human prostate tissue for evaluation of the cellular distribution or the initial concentration of steroid receptors in human prostate tissue are discussed.