Podocyte Injury in Autosomal Dominant Polycystic Kidney Disease.

BACKGROUND/AIMS: Autosomal dominant polycystic kidney disease (ADPKD) is a tubulointerstitial disease. Different degrees of glomerular affection in ADPKD may affect the further course of disease in which it may hypothetically be secondary to the result of glomerular involvement causing podocyte injury. Our aim was to compare urinary excretion of podocin and podocalyxin, which are biomarkers of podocyte injury, and to assess their relationship with proteinuria and renal function in ADPKD.

METHODS

Fifty-six patients with ADPKD and 28 volunteers were enrolled to study. Podocin, podocalyxin protein levels, and proteinuria were measured in urine. Patients were categorized based on their estimated glomerular filtration rate (eGFR).

RESULTS

Patients with ADPKD had higher podocin and podocalyxin levels compared to the control group. The levels of podocin and podocalyxin were higher in ADPKD patients both with eGFR ≥60 mL/min/1.73 m2 and with eGFR <60 mL/min/1.73 m2 than in controls. The levels of podocin and podocalyxin were higher in ADPKD patients with eGFR <60 mL/min/1.73 m2 than in ADPKD patients with eGFR ≥60 mL/min/1.73 m2. Podocin and podocalyxin were negatively correlated with eGFR and positively correlated with urine protein to creatinine ratio in ADPKD patients.

CONCLUSION

Urine biomarkers of podocytes injury were significantly higher in ADPKD patients even in the early stage of the disease than in the control group. It should be clarified whether these biomarkers can provide new prognostic parameters for disease surveillance.