Introduction: Progressive proteinuria and glomerulosclerosis characterize chronic allograft nephropathy. However, the causes are not fully elucidated. Injury of parietal epithelial cells in glomeruli, the podocytes, is the initiating cause of many renal diseases, leading to proteinuria with possible progression to glomerulosclerosis. Podocytes are highly specialized cells, with an important role in maintaining the glomerular filtration barrier and producing growth factor for mesangial cells and endothelial cells. With their foot processes they cover the glomerular basement membrane, and form slit diaphragms with neighboring podocytes. The potential role of podocytes in the failing transplanted kidney is unknown.
Objectives: To evaluate podocyturia as a functional marker in pregnant women with kidney grafts.
Methods: Twenty pregnant women with kidney grafts had their urine samples cytocentrifugated and evaluated by indirect immunofluorescence. The slide was incubated for 45' at room temperature with fluorescein (FITC) anti-rabbit IgG secondary antibody (Sigma-Aldrich, EUA). Then Vectashield (mounting medium for fluorescence) with DAPI (4'6-diamino-2-fenilindol dihidrocloreto) were applied H-1200 (Vector laboratories, inc, USA). The podocytes and the total number of cells were counted in 15 fields photographed under 400x magnification with a digital camera coupled to an epifluorescence microscope DM1000 (Leica, Germany) connected to a computer. The results were expressed as podocyte/total cells (%) per area of higher cell concentration (hot spots) in the field of 400x detected by staining of nuclei and cytoplasm. (Grant FAPESP 08/56338-1).
Results: The mean age of the women was 26years. The urinalysis was performed at the third trimester of gestation; 11 did not exhibit urinary podocytes and 9 had podocyturia. There was also a relationship between blood pressure levels, proteinuria and the excretion of podocytes.
Conclusion: Urinary podocyte number, blood pressure and proteinuria were associated. We observed that urinary podocyte excretion occurs in pregnant women with kidney transplant almost synchronously with higher systolic and diastolic blood pressure and higher mean levels of proteinuria. The detection of podocyturia in these women could be useful for early diagnosis and follow-up of glomerular injury, eventually preeclampsia. It may be also associated to its severity or activity, although additional studies are necessary to confirm these aspects.
Copyright © 2012. Published by Elsevier B.V.