OBJECTIVETo characterize age-related cellular phenotype alterations and growth rates of human prostatic stromal cell cultures from the normal prostatic peripheral zone of young donors (PZ-young) and old donors (PZ-old).

METHODSWe isolated stromal cells from 10 donors of different ages, assessed the cellular phenotypes by immunocytostaining for prolyl-4-hydroxylase, alpha-smooth muscle actin (alpha-SMA) and desmin, and analysed the ultrastructure by transmission electron microscopy (TEM). The proliferation and apoptosis of the cells were determined by Cell Counting Kit-8 assay and flow cytometry, respectively.

RESULTSAll the stromal cells were positive for prolyl-4-hydroxylase regardless of the donors' age, while alpha-SMA and desmin positive cells increased with their age. The positive expressions of alpha-SMA and desmin were (2.56 +/- 1.81)% and (0.89 +/- 0.93)% in PZ-young, and (38.89 +/- 11.22)% and (14.89 +/- 5.97)% in PZ-old (P < 0.01). The alpha-SMA- and/or desmin-positive stromal cells were morphologically large, flat and polygonal. Ultrastructural analysis showed that the cell cultures from PZ-old were richer in rough endoplasmic reticulum and golgi complexes. The stromal cells of PZ-old had a lower growth rate than that of PZ-young (P < 0.01), but there was no significant difference in the apoptosis rate between the two groups.

CONCLUSIONCellular phenotypes of human prostate stromal cell cultures change with the increase of age from predominantly typical fibroblasts to a mixture of fibroblasts and myofibroblasts, which might responsible for the high incidence of prostate cancer in elderly men.