Does N-Carboxymethyl Lysine Serve as a Prognostic Biomarker of Diabetic Nephropathy?

Abstract

Introduction: The occurrence and progression of diabetic nephropathy to end stage disease mandates an early detection of kidney damage. Glycation and oxidation injury form an essential element in the evolution of diabetic complications both microvascular and macrovascular. Aim: To study the trends in the N-Carboxymethyl lysine levels in various stages of diabetic nephropathy and assess its efficacy as a prognostic marker for diabetic nephropathy. Materials and Methods: The study included 125 Type 2 diabetic individuals- 45 patients with normoalbuminuria, 40 patients having microalbuminuria and 40 with macroalbuminuria {based on the Albumin-Creatinine Ratio (ACR)}. Forty five non-diabetic healthy individuals were included as a control group. Serum N-carboxymethyl lysine quantification was done for all the study participants and compared and correlated with other parameters across various groups. Results: The fasting and postprandial sugar, glycosylated haemoglobin, triglycerides, duration of diabetes, systolic and diastolic blood pressure, Body Mass Index (BMI), all were strong risk factors for Diabetic Kidney Disease (DKD) progression which significantly correlated positively with microalbumin and urine ACR (uACR) and negatively with Glomerular Filtration Rate (GFR). The serum N-carboxymethyl lysine was observed to be significantly increased as the ACR increased and in comparison to the controls, respectively (p-value <0.001). The GFR showed significant negative correlation with levels of serum N-carboxymethyl lysine whereas positively correlated with fasting and postprandial sugar, glycosylated haemoglobin, triglyceride levels, duration of diabetes, systolic and diastolic blood pressure, BMI, microalbumin and uACR. Conclusion: N-carboxymethyl lysine in serum can serve as an early marker for diabetic nephropathy and its progression and severity.