Elevated Urinary biomarkers KIM-1 and NGAL may predict occurrence of Chronic Interstitial Nephritis (CINAC) in rural Sri Lanka

Abstract

Chronic Interstitial Nephrities (CINAC) that cannot be attributed to known etiologies has encountered in rural Sri Lanka. CINAC is a tubular disease, urine albumin or albumin–creatinine ratio (ACR) is still being used as the screening tool. However they are incapable of assessing early stages of CINAC due to lack of sensitivity and specificity. In present study, we report the use of non-invasive, rapid and sensitive marker of tubule-epithelial cell damage (KIM-1 & NGAL) for early CINAC diagnosis among sugarcane farmers in UP, Sri Lanka. Urine samples were collected from non-endemic controls living in wet zone (Matara-M) and in two locations representing sugarcane farmers ( Rahathangama (R1-S, R2-S) and Warunagama (W-S). Urinary KIM-1 and NGAL levels were measured using specific KIM-1 (Cusabio, P.R. China) and NGAL (Ray Biotech, USA) Enzyme Linked Immuno Sorbent Assay kits. Urine Creatinine was measured using Jaffe rate-blanked creatinine assay and final KIM-1 and NGAL were adjusted to UC. Urinary KIM-1 (μg/g Cr) and NGAL (ng/mg Cr) concentrations in M group were (2.885 ± 0.524, Mean ± SEM) and (0.568 ± 0.108) respectively. Mean KIM-1 in R1-S (12.49; 0 – 34.91 range) and R2-S (10.53; 0 – 61.66) were 4 times higher than M. NGAL concentrations in R1-S (1.93) and R2-S (1.06) were also significantly different from the M control group (p<0.05). In W-S, creatinine adjusted urinary KIM-1 was 5.45 μg/g Cr and significantly lower than the R1-S and R2-S. However significantly higher urinary NGAL was reported in W-S (1.94 ng/mg Cr) with compared to control group (M). This study revealed that both urinary KIM-1 and NGAL concentrations were higher in sugarcane farmers with compared to the control group indicating that urinary KIM-1 and NGAL concentrations may be used as early predictive biomarkers for CINAC cases in rural Sri Lanka