Ultrastructural Study of Podocyte Alterations inPodocytopathies
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Abstract
Introduction: Ultrastructural alterations in podocytes are an important diagnostic and prognostic marker of nephropathies. However, the biomedical understanding of the detected submicroscopicalteratuons in podocytes, such as effacement of cytopodia and naked glomerular basement membrane, remains controversial.
The aim of this study was to investigate the relationship between ultrastructural changes in podocytes (cytopodiaeffacement andnaking of glomerular basement membrane) with a number of clinical and laboratory indicators of renal dysfunction using the example of podocytopathies.
20 patients (11 men, 9 women) were examined. Patients with podocytopathies were represented by: focal segmental glomerulosclerosis - 8 anddisease of minimal changes- 12.
Materials and methods: All patients underwent standard laboratory and instrumental studies: total serum cholesterol. mmol / l;blood serum protein. g / l; serum creatinine. mmol / l; urea. mmol / l; serum albumin g / l; glomerular filtration rate according to CKD-EPI. ml / min / 1.73 m²; daily protein loss g / day
Light microscopy changes:Glomerulosclerosis were assessed quantitatively: glomeruli completely sclerosed and / or with focal segmental sclerosis were considered. Quantitative ultrastructural stereological analysis was performed by evaluating the cytopodial width (FPW) and the degree of naked glomerular membrane (% NGBM) of the glomeruli.
Results: In podocytopathies. the largest number of sclerosed glomeruli was observed in focal segmental glomerulosclerosis. which was accompanied by the lowest daily proteinuria and glomerular filtration rate. Quantitative values of the cytopodia width were associated with the level of daily protein loss (r = 0.34. p> 0.05) and serum albumin level (r = - 0.53, p <0.05) in patients with nephrotic syndrome. Correlation analysis of the values of the cytopodia width and %naked glomerular basement membrane in patients with podocytopathies revealed a statistically significant negative interrelation of these morphometric parameters. (r = -0.54, p = 0.012).
Conclusions: In patients with podocytopathy a correlation between the severity of nephrotic syndrome and proteinuria / hypoalbuminemia on the one hand and the cytopodia width on the other was found. The revealed negative relationship between the width of the cytopodia and the%of the naked glomerular basement membrane in patients with podocytopathiescould be a consequence of the early stages of podocytes damage, accompanied by transient naked glomerular basement membrane.