Diagnostic significance of podocyte-associated biomarkers in renal failure patients before dialysis: a case-control study

Background: Renal failure is a progressive injury of the glomerular filtration barrier, particularly the podocytes (foot cells) that are crucial for the integrity of the glomerulus. Their injury results in disruption of slit diaphragm proteins, proteinuria and kidney disease exacerbation. The structural importance of podocyte-associated proteins is well-documented in renal tissues, though there is a distinct lack of studies evaluating their collective diagnostic potential in the circulation, particularly in patients at the critical stage immediately before starting their dialysis sessions. Objective: This study aimed to assess the level of podocin–associated proteins involved in regulating permeability and maintaining the structure of the kidney filtration barrier, particularly podocin, synaptopodin, β-arrestin-1 and nephrin in the serum of renal failure patients before dialysis. Methods: The present case-control study consisted of 30 healthy persons and 60 patients with chronic renal failure. Podocin, synaptopodin, β-arrestin-1, and nephrin levels were quantified by ELISA. Clinical data were analysed using an independent Student’s t-test, and diagnostic performance was assessed by the ROC curve analysis. Results: The significant increase in the serum levels of podocin, synaptopodin, β-arrestin-1 and nephrin in renal failure patients as compared with the healthy control group was found. No statistically significant difference in the level of these proteins between the male and female patients was detected. A significant rise in nephrin level was observed among overweight individuals in comparison to those of normal weight. ROC curve analysis demonstrated the diagnostic capability of the studied proteins, indicating their clinical utility in the diagnosis of renal injury. Conclusions: Measuring a combination of podocyte-associated proteins may allow an integrated view of renal injury and glomerular damage. Podocin, synaptopodin, β-arrestin-1, and nephrin serum levels are altered in renal failure patients before dialysis and might serve as sensitive biomarkers for renal damage.