Relationship between renal tubulointerstitial fibrosis and serum prolidase enzyme activity

Abstract

Objectives: The severity of interstitial fibrosis/tubular atrophy (IFTA) is the most important determinant of the irreversible progression of chronic kidney disease (CKD). Prolidase is the key enzyme in collagen turnover and is associated with an extracellular matrix increase. We aimed to evaluate the relationship between the presence and degree of IFTA and serum prolidase enzyme activity (SPEA) in patients undergoing a renal biopsy. Methods: This cross-sectional study included 56 patients who underwent a renal biopsy (30 males; mean age 45.3 +/- 16.8 years) and also 54 healthy volunteers (21 males; mean age 42.7 +/- 8.2 years). IFTA scoring was performed on the basis of percentage of IFTA presence in renal biopsy tissues (1=<10%; 2=10-24%; 3=25-50%; 4=>50%). SPEA was measured by spectrophotometric method. Results: The proteinuria and SPEA levels of the patients were significantly higher than the controls (p<0.001 and p<0.001, respectively). SPEA decreased significantly when the IFTA score increased (p<0.002). In the correlation analysis, the IFTA score was negatively correlated with SPEA (r(s)=-0.461, p<0.001), and positively correlated with proteinuria (r(s)=0.274, p=0.041). Conclusion: These findings suggest that increased collagen turnover decreases over time concerning the progression of renal fibrosis. Monitoring of SPEA level may useful as a biomarker for early determination of CKD progression and severity.