Visceral epithelial cells in rat glomerular cell culture.

The purpose of this study was to identify and characterize visceral epithelial cells (VECs) of renal glomeruli in culture. Such cells have been described variably as regular, polygonal cells showing a high rate of replication and a cobblestone-like appearance at confluence and also as irregular, arborized and often multinucleated cells showing a very limited proliferative capacity. We examined early outgrowths from the glomeruli by immunofluorescence microscopy using antibodies specific for VECs (anti-podocalyxin(1A), anti-pp44 and 5-1-6), for endothelial cells (anti-von Willebrand factor (vWF) and RECA-1) and for mesangial cells (anti-Thy-1). 1A and anti-pp44 reacted with several types of irregular, arborized cells, but never with regular, polygonal cells. 5-1-6 did not react with any of the cells. Neither the 1A- nor anti-pp44-positive cells (1A/pp44(+) cells) stained with anti-vWF, RECA-1 or anti-Thy-1. However, all the 1A/pp44(+) cells expressed desmin and vimentin but not cytokeratin. These results show that the 1A/pp44(+) cells are derived from VECs, supporting the idea that most polygonal cells in glomerular cultures are of parietal epithelial origin.