Podocalyxin-positive glomerular epithelial cells in urine correlate with a positive outcome in FSGS

Abstract

Parietal epithelial cells (PECs) and podocytes are the 2 epithelial cell types in the glomerulus. In contrast to podocytes, PECs have the ability to proliferate lifelong, and they can transdifferentiate into other cell types. We previously published that excretion of podocalyxin (PDX)-positive PECs in the urine correlates with disease activity in different glomerular diseases. In this analysis we investigated whether excretion of PDX-positive cells in the urine might have a prognostic value for proteinuria development and kidney function in focal segmental glomerulosclerosis (FSGS). We found that patients diagnosed with FSGS and with significant excretion of PDX-positive cells in the urine had a negative change in serum creatinine in the follow-up analysis. In contrast to that, FSGS-patients without excretion of PDX-positive cells showed a positive change in serum creatinine. There was a significant negative correlation between PDX-positive cells in the urine and change in serum creatinine. Mean change in urine protein in FSGS patients with excretion of PDX-positive cells in the urine did not differ significantly from patients with no cell excretion, but we could demonstrate a negative correlation between PDX-positive cells and change in total urine protein. Our data suggest that FSGS patients excreting large amounts of PDX-positive cells in their urine have a better outcome regarding kidney function and proteinuria compared with patients without excretion of PDX-positive cells. These data imply that PDX-positive cells have a positive effect on podocyte regeneration in FSGS patients.