Differential growth rates in stromal cultures of human prostate derived from patients of varying ages

BACKGROUND. This study was undertaken to attempt to characterize changes in in vitro growth rates and cellular phenotypes of human prostatic stroma associated with aging and/or development of benign prostatic hyperplasia (BPH). METHODS. Prostate stromal cell strains were established from 12 tissue donors of varying age. Culture growth rate was determined by cell counts over a 6-day period. Cell phenotype was assessed by immunocytochemical staining for smooth muscle α-actin, smooth muscle myosin, and prolyl-4-hydroxylase. RESULTS. Growth rates of prostate stromal strains in vitro varied. Stromal cells derived from aged males with BPH had significantly slower growth rates than cells from younger donors. A positive reaction for prolyl-4- hydroxylase, a mesenchymal cell marker, was present in all cell cultures regardless of donor age. Expression of smooth muscle-specific actin, a nonspecific smooth muscle cell marker, was present in 48-79% of prostate stromal cultures. Staining for smooth muscle myosin, a specific smooth muscle cell marker, was found to vary significantly with age. The percentage of smooth muscle myosin-positive cells derived from males aged 15, 45, 57, and 72 years were 0.70 ± 0.14%, 2.12 ± 0.30%, 4.20 ± 0.89%, and 26.25 ± 1.0%, respectively. The shape and size of actin- and/or myosin-positive stromal cells from a 72-year-old donor culture were also usually larger and polygonal in shape as compared to thin and elongated shapes in 15-year-old donor cultures. The shape of actin- and/or myosin-positive cells from a 45-year- old donor culture demonstrated both phenotypes. CONCLUSIONS. These results suggest that in human prostate stromal cells cultured as described, the growth rate decreases, the percent of smooth muscle cells increases, and the cellular shape changes with increasing donor age and or/development of BPH.