PROLIFERATIVE ACTIVITY OF INTRINSIC CELL-POPULATIONS IN THE NORMAL HUMAN KIDNEY

The proliferative activity of various normal human renal cell populati ons is unknown. Recently, antibodies to cell proliferation-associated nuclear proteins, such as proliferating cell nuclear antigen (PCNA) an d Ki-67, which are applicable to archival paraffin sections, became av ailable. With antibodies to PCNA and Ki-67 after microwave pretreatmen t of the paraffin sections, the proliferation indexes (ratio of positi ve nuclei with PCNA and Ki-67 antibodies/all nuclei counted x 100, i.e , percentage of positive cells) of 12 different intrinsic renal cell p opulations in 20 normal human kidneys have been determined. The follow ing proliferation indexes (percentages of positive cells) were found w ith the PCNA and the Ki-67 antibodies, respectively: proximal tubular epithelium, 0.22, 0.24; thin limb of Henle, 0.29, 0.30; thick ascendin g limb of Henle, 0.32, 0.29; distal tubular epithelium (distal convolu ted tubules and cortical collecting ducts), 0.33, 0.44; medullary coll ecting ducts, 0.32, 0.3; glomerular mesangial cells, 0.07, 0.12; glome rular visceral epithelial cells, 0.04, 0.08; glomerular parietal epith elial cells, 0.07, 0.1; glomerular capillary endothelium, 0.42, 0.47; peritubular capillary endothelial cells, 0.38, 0.43; endothelium of la rge intrarenal vessels (arteries and veins), 0.09, 0.12. Thus, normall y capillary endothelium (glomerular and peritubular) appears to have t he highest proliferation index in the human kidney by these techniques . These results indicate major variation in the proliferative activity of normal human renal cell populations, along with a significant corr elation between PCNA and Ki-67 staining. Furthermore, this study provi des normal values for the proliferative activity of different human re nal cell populations. Our results can serve as reference values for su bsequent studies on various pathologic renal changes, where variations of proliferation indexes from normal may reflect the level of disease activity.