Identification of multinucleated cells in human kidney cortex: A way for tissue repairing?

Abstract

The presence of multinucleated cells has never been demonstrated in renal tissue, although, polyploid cells were recently observed in the tubules of normal and pathological human kidney. Therefore, the aim of the present study is to identify and quantify, by electron microscopy, multinucleated cells in the cortical tissue of normal human kidney i.e., in the three compartments of renal tubule: the proximal tubule (PT), the distal tubule (DT), and the collecting duct (CD), as well as, in the glomerulus (podocytes). The percentage of the multinucleated cells observed was 5% (95%CI: 3.6%-6.7%) in renal cortical tubules with distribution in each tubular compartment of 6% in PT, 4% in DT and 3% in CD with no statistically significant difference in the distribution of multinucleated cells according to tubular compartments. Four percent of analysed podocytes (in total 149 podocytes) were multinucleated (95%CI: 1.5%-8.6%). In conclusion, multinucleated cells were identified and quantified in functionally normal kidneys, as previously demonstrated in other organs such as the liver.

Keywords: electron microscopy; kidney; multinucleate cells; podocytes; quantitative analysis.

FIGURE 1

Semithin sections stained with toluidine blue of normal human renal cortical tissue that show in (a) a binucleate hypertrophic cell (white asterisk) in the proxmal tubule and in (b) two binucleate podocytes (arrows) in the glomerulus. Scale bar: a and b = 40 µm

FIGURE 2

Normal human renal tissue. Ultrastructure of binucleate cells identified in proximal tubule (a), distal tubule (b), collecting duct (c) and in a podocyte of the glomerulus (d). Scale bar: a = 6.5 µm; b = 5 µm; c = 4.5 µm; d = 6.5 µm

FIGURE 3

Ultrastructure of a binucleate cell contained in the macula densa (a) of normal human renal tissue. A binucleate hepatocyte of normal human liver (b) is shown as control. BC, bile canaliculus. Scale bar: a and b = 3 µm