Relationship Between Neutrophil Gelatinase Associated Lipocalin And Chronic Kidney Disease

Abstract

The attention being paid globally to chronic kidney disease is attributable to five factors: the rapid increase in its prevalence, the enormous cost of treatment, recent data indicating that overt disease is the tip of an iceberg of covert disease, an appreciation of its major role in increasing the risk of cardiovascular disease and the discovery of effective measures to prevent its progression. Recent observations have pointed out the crucial role of the renal tubule in the genesis and progression of CKD; independently of the primary disease and the eventual presence of superimposed damaging conditions, the pathogenic mechanisms causing progressive renal destruction converge on a common tubulo-interstitial pathway characterized by tubular atrophy and hypoxia, peritubular capillary injury and interstitial fibrosis, ultimately explaining the irreversible evolution to terminal uremia. NGAL, a small 25-kDa protein belonging to the lipocalin family, as one of the most promising biomarkers in the diagnostic field of acute kidney injury. NGAL production from tubular cells may reflect the entity of active renal damage that underlies the chronic impairment condition NGAL may be the way to follow up patients with chronic kidney disease in different nephrology clinics so as to prevent the development of end-stage renal disease and possibilities of dialysis and kidney transplantation with their complications. In our study, NGAL was measured in a cohort of patients affected by non advanced CKD with stable renal function. Interestingly, apart from the already cited predictive value, a strict, independent, and inverse correlation with estimated GFR was described for both serum NGAL and urinary NGAL, suggesting that under these particular conditions this protein may also represent a surrogate index of residual renal function. Our study included 30 patients with chronic kidney disease secondary to variable causes. A urine and serum samples were collected from each patient to be estimated for NGAL and calculated for fractional excretion for NGAL in relation to serum, urinary creatinine and GFR calculated by MDRD formula. Patients with cancer, infections, alterations in leucocytic count or severe glomerular filtration reduction (< 15 ml/min) will be excluded from the study in order to avoid potential confounding factors. Serum NGAL shows highly significant positive correlation with serum creatinine and highly significant negative correlation with GFR. Urinary NGAL shows highly significant positive correlation with serum creatinine and highly significant negative correlation with GFR. Fractional excretion of NGAL shows highly significant positive correlation with serum creatinine and highly significant negative correlation with GFR. The relations between GFR and NGAL values (serum NGAL, urinary NGAL and FE fractional excretion of NGAL) were closer than that between GFR and serum creatinine. NGAL values show positive significant correlations with serum creatinine. Findings from the present study clearly indicate that NGAL represents a novel risk marker of CKD progression.