P0221SOLUBLE UROKINASE RECEPTOR (SUPAR) IS A PREDICTOR OF DISEASE STATE AND RENAL PROGNOSIS IN PRIMARY NEPHROTIC SYNDROME

Abstract Background and Aims A hypothesis has been proposed that serum (s-) soluble urokinase receptor (suPAR) activates glomerular podocyte β3 integrin to cause podocyte injury and onset of proteinuria in primary nephrotic syndrome (pNS). However, s-suPAR has been questioned as a disease marker for pNS because it did not correlate with urinary protein (UP). Furthermore, there are a few reports that suggested a correlation between urinary (u-) suPAR and UP by univariate analysis, but the correlation between the two has not been studied by multivariate analysis taking confounding factors into account. In addition, it is unclear how u-suPAR is involved in the pathogenesis of pNS. Method In 36 patients with pNS including minimal change (n=18), focal segmental glomerulosclerosis (n=7), membranous nephropathy (n=9) and membranoproliferative glomerulonephritis (n=2), the relationship between u-suPAR (pg/mgCr) and UP (g/gCr) was examined by cross-sectional analysis of baseline values before treatment and longitudinal analysis of changes during the first 2 months of treatment (⊿). In addition, the localization and staining intensity of activated β3 integrin in renal tissue were examined by immuno-histochemistry methods. We also examined whether s-suPAR (pg/ml) or u-suPAR is useful for predicting renal prognosis (1.5-fold increase from baseline in s-Cr) using Cox proportional hazard analysis. Results In cross-sectional analysis, u-suPAR was a UP predictor independent of s-suPAR, eGFR and selectivity index (S.I.) [standardized partial regression coefficient (stdβ) = 0.879, p