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


CONCLUSIONS
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.
Clinical Chemistry Service, University Hospital, Federal University of Maranhão, Brazil.
Maria de Fátima Castro
Mde F
Mendes
Kidney Disease Prevention Centre and Department of Physiological Sciences, Federal University of Maranhão, Brazil. Electronic address: joao.salgado@ufma.br.
João Victor
JV
Salgado
Clinical Chemistry Service, University Hospital, Federal University of Maranhão, Brazil.
José
J
de Ribamar Lima
Kidney Transplant Service, University Hospital, Federal University of Maranhão, Brazil.
Teresa Cristina Alves
TC
Ferreira
Department of Pathology, Federal University of Maranhão, Brazil.
Gyl Eanes Barros
GE
Silva
Kidney Disease Prevention Centre and Department of Medicine I, Federal University of Maranhão, Brazil.
Natalino Salgado
NS
Filho
D000328:Adult; D064591:Allografts; D003404:Creatinine / Q000097:blood / Q000652:urine; D055316:Cystatin C / Q000032:analysis* / Q000097:blood; D005260:Female; D005355:Fibrosis / Q000652:urine*; D005919:Glomerular Filtration Rate; D006801:Humans; D016030:Kidney Transplantation; D007684:Kidney Tubules / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012964:Sodium / Q000032:analysis
D055316:Cystatin C; D012964:Sodium; D003404:Creatinine
Cystatin C; Interstitial fibrosis tubular atrophy; Kidney allograft; Kidney transplantation; Renal biopsy; Urinary biomarkers