Urinary Podocyte Excretion and Proteinuria in Patients Treated with Antivascular Endothelial Growth Factor Therapy for Solid Tumor Malignancies

Urinary Podocyte Excretion and Proteinuria in Patients Treated with Antivascular Endothelial Growth Factor Therapy for Solid Tumor Malignancies

Oncology, June 2014

24902997

Suzanne R. Hayman, Juan C. Calle, Aminah Jatoi, Iasmina M. Craici, Steven J. Wagner, Amy L. Weaver, Eddie L. Greene, Joseph P. Grande, Vesna D. Garovic

Background: Urinary podocyte excretion (podocyturia) may function as a more specific marker of ongoing glomerular damage. This study sought to analyze the relationship between proteinuria and podocyturia in cancer patients treated with antivascular endothelial growth factor (anti-VEGF) agents. Methods: Thirty-seven patients treated with anti-VEGF medications were analyzed in a single-institution, cross-sectional study. Podocyte cultures were performed on random urine collections (50-100 ml), and podocytes were identified by positive podocin staining. The corresponding urine samples were analyzed for protein and creatinine (Cr) measurements. Results: Proteinuria ≥0.5 g/g Cr was found in 30% of the patients (median, 0.12; interquartile range, 0.04-0.86), and 62% had podocyturia. There was a significant difference in the amount of podocyturia between patients with proteinuria ≥0.5 g/g Cr and those with a value <0.5 g/g Cr (median podocyturia, 1.08 cells/mg Cr, range, 0-14.55 vs. 0.03 cells/mg Cr, range, 0-1.64, respectively; p < 0.001). A statistically significant correlation was observed between the cumulative dose of bevacizumab and both proteinuria (r = 0.48, p = 0.004) and podocyturia (r = 0.34, p = 0.045) as well as between proteinuria and podocyturia (r = 0.63, p < 0.001), suggesting that these are mechanistically related. Discussion: Ongoing podocyte loss may be mechanistically related to the onset and severity of proteinuria in patients treated with anti-VEGF agents. © 2014 S. Karger AG, Basel.