Increased urinary cystatin C level is associated with interstitial fibrosis and tubular atrophy in kidney allograft recipients

Aim: The objective of this study was to investigate the correlation between the urinary excretion of cystatin C (CysC) and the presence of interstitial fibrosis/tubular atrophy (IF/TA) in renal transplant (RT) recipients. Methods: This prospective study included 21 adult patients who had undergone renal biopsy and RT >= 6 months prior. According to the renal biopsy reports, the patients were divided into groups with (n = 12) or without (n = 9) IF/TA. Analytical parameters included the following: serum and urinary levels of CysC, creatinine (Cr) and sodium (Na), total urinary protein, urinary CysC/creatinine ratio [u(CysC/Cr)], fractional excretion of sodium (FENa) and estimated glomerular filtration rate (eGFR) based on the Chronic Kidney Disease Epidemiology Collaboration equation. Results: The values of uCysC, u(CysC/Cr), proteinuria, and FENa were significantly higher in patients with IF/TA than in patients without IF/TA. The values of eGFR were statistically lower in patients with IF/TA (p = 0.001). Values of uCysC significantly correlated with those of serum Cr, FENa, and eGFR (p < 0.001). Among the patients with IF/TA, 67% presented with glomerulosclerosis (segmental/global). Conclusion: Elevated levels of urinary CysC are associated with interstitial fibrosis and tubular atrophy in RT recipients and may become a useful tool for monitoring kidney allografts. (C) 2015 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.