Podocyte biology: Proteolytic processing in podocytes

Correlation between reabsorbed intracytoplasmic proteins in glomerular podocytes and the level of proteinuria in patients with glomerulopathies

Podocytes can handle proteins when the glomerular filtration barrier is injured with leak of proteins out of the vasculature into the urine. The correlation between the number of podocytes involved in handling leaked proteins, as well as the extent of up-taken proteins in podocytes cytoplasm on one side, and the level of proteinuria in the concerned patients on the other side, is evaluated. A retrospective study of 22 patients with clinical proteinuria caused by various glomerulopathies was retrieved and analyzed. The glomerulopathies in the concerned patients were pathologically diagnosed through microscopic examination of the submitted renal biopsies over a period extending from January, 2013 to December, 2016. Additionally, three cases with protein levels in urine within the acceptable normal range were also analyzed as controls. Electron microscopic examination of the glomerular podocytes in the relevant cases constituted the base for the present study. Among the studied cases, it was noted that the greater the number of glomerular podocytes with reabsorbed proteins within the cytoplasm, the lower the level of proteinuria. Comparatively, cases with fewer numbers of podocytes with reabsorbed proteins disclosed higher levels of proteinuria. The present study might be the first to shed light on the correlation between morphologically recognizable glomerular podocytes with reabsorbed proteins and the level of proteinuria in patients with various glomerulopathies. The current study may constitute a base for the future research work concerned with the structural changes of glomerular podocytes as an adaptive mechanism in cases of proteinuria.