Podocyturia is significantly elevated in untreated vs treated Fabry adult patients

Abstract

Background: Proteinuria suggests kidney involvement in Fabry disease. We assessed podocyturia, an early biomarker, in controls and patients with and without enzyme therapy, correlating podocyturia with proteinuria and renal function. Methods: Cross-sectional study (n = 67): controls (Group 1, n = 30) vs. Fabry disease (Group 2, n = 37) subdivided into untreated (2A, n = 19) and treated (2B, n = 18). Variables evaluated: age, gender, creatinine, CKD-EPI, proteinuria, podocyte count/10 20× microscopy power fields, podocytes/100 ml urine, podocytes/g creatininuria (results expressed as median and range). Results: Group 1 vs. 2 did not differ concerning age, gender and CKD-EPI, but differed regarding proteinuria and podocyturia. Group 2A vs. 2B: age: 29 (18–74) vs. 43 (18–65) years (p = ns); gender: males n = 3 (16 %) vs. n = 9 (50 %). Proteinuria was significantly higher in Fabry treated patients, while CKD-EPI and podocyturia were significantly elevated in untreated individuals. Significant correlations: group 2A: age-proteinuria, ρ = 0.62 (p = 0.0044); age-CKD-EPI, ρ = −0.84 (p < 0.0001); podocyturia-podocytes/100 ml urine, ρ = 0.99 (p = 0.0001); podocyturia-podocytes/g creatininuria ρ = 0.86 (p = 0.0003), podocytes/100 ml urine-podocytes/g urinary creatinine, ρ = 0.84 (p = 0.0004); proteinuria-CKD-EPI, ρ = −0.68 (p = 0.0013). Group 2B: podocyturia-podocytes/100 ml urine, ρ = 0.88 (p < 0.0001); podocyturia-podocytes/g creatininuria, ρ = 0.84 (p < 0.0001); podocytes/100 ml urine-podocytes/g creatininuria, ρ = 0.94 (p < 0.0001); CKD-EPI-proteinuria, ρ = -0.66 (p = 0.0028). Conclusions: Patients with Fabry disease display heavy podocyturia; those untreated present significantly higher podocyturia, lower proteinuria and better renal function than those who are treated, suggesting that therapy may be started at advanced stages. Podocyturia may antedate proteinuria, and enzyme therapy may protect against podocyte loss.