Branching activity in the human prostate: a closer look at the structure of small glandular buds.
ABSTRACT Knowledge regarding cell biologic characteristics of small solid glandular buds in the prostate and their relationship with branching activity in the human prostate is still fragmentary. Our object was to demonstrate, on the basis of immunophenotype, loci that harbor the potential for branching activity within the adult human prostate.
Semiserial sectioning was performed on 13 adult prostates in an effort to identify structures in the prostate that could be considered foci of growth. Selected slides were stained with biomarkers for basal/luminal cells (keratins), proliferation (MIB-1), apoptosis inhibitor (bcl-2), intercellular adhesion (E-cadherin), and stromal-epithelial interactions (tenascin-C). Results were compared with fetal and prepubertal human prostates and microdissected rat prostates.
Five histologic epithelial structures were identified in 19 paraffin blocks, which on serial sectioning showed morphologic transitions with a common pattern, consisting of reduction in number and caliber of acini until small solid buds of epithelial cells were reached. Immunophenotypically, the small solid glandular buds had a basal-cell keratin phenotype, expression of bcl-2 in virtually all cells, high proliferative activity, prominent intracellular localization of E-cadherin, and enhanced periglandular tenascin-C immunoreactivity. The budding tips in fetal and prepubertal prostates revealed an immunostaining pattern identical to the small solid glandular buds in the adult, but different to the rat prostate.
Our data suggest that dispersed small solid glandular buds have a capacity for growth, and as such may be considered foci of resumed reawakening branching activity with in the adult human prostate.
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ABSTRACT: Background To gain further insight into the molecular cell biologic features of prostate development, we investigated the proliferative activity of prostate epithelial and stromal cells and their topographic relationship with neuroendocrine (NE) cell distribution and regional heterogeneity.Methods Consecutive sections from 43 prostates taken during autopsy representing fetuses (12–38 weeks of gestation), infants, prepubertal males and adults were double stained for chromogranin A and MIB-1. MIB-1 labeling index (LI) was calculated in the budding tips, forming acini, major collecting ducts, adjacent and non-adjacent stromal compartments. Furthermore, the topographic relationship between proliferating cells and NE cells was evaluated.ResultsIn the first half of gestation, cell proliferation as revealed by MIB-1 LI was significantly higher in epithelial structures and stroma than in older fetuses and other age groups. MIB-1 LI was higher in budding tips than in other epithelial regions. MIB-1 LI in stroma adjacent to budding tips was not higher than that adjacent to other epithelial branching segments. Co-expression of chromogranin A and MIB-1 staining was not observed. MIB-1 LI was lower in cells in the direct vicinity of chromogranin A positive NE cells than at a distance from NE cells.Conclusions Prostate development in the first half of gestation is explosive. Thereafter, the prostate basically is a slow-growing organ. Budding tips are the major growth foci during early prostate development, while stromal growth is evenly distributed throughout the prostate, probably indicating that stromal-epithelial interactions do not manifest in enhanced proliferation at their interface. NE cells may have an inhibitory effect on proliferation of exocrine epithelial cells and are probably only associated with differentiation of prostate exocrine cells in the prostate. Prostate 49:132–139, 2001. © 2001 Wiley-Liss, Inc.The Prostate 10/2001; 49(2):132 - 139. DOI:10.1002/pros.1127 · 3.57 Impact Factor