Elevation of Nε-(carboxymethyl)lysine-modified advanced glycation end products in chronic liver disease is an indicator of liver cirrhosis

Objectives: Progression of liver fibrosis to cirrhosis is a dire consequence of chronic liver diseases (CLD). Nε-(carboxymethyl)lysine (CML)-modified advanced glycation end products (AGEs) in patients with CLD could reflect the degree of severity of the disease. Design and methods: In 110 patients with CLD and 124 healthy controls, CML serum levels and their diagnostic sensitivity and specificity were determined and compared to hyaluronan (HA). Results: Serum levels of CML were significantly affected by the stage of liver cirrhosis and were closely associated with liver function capacity. CML correlated positively with HA (r = 0.639, P < 0.0001). In ROC analysis, the diagnostic sensitivity and specificity in distinguishing healthy controls from liver disease patients for CML (AUC 0.908; 95%-CI 0.863–0.942, cut-off 640 ng/mL, sensitivity 74.5% and specificity 97.6%) resembled HA (AUC 0.948; 95%-CI 0.907–0.974; cut-off 50 ng/mL, sensitivity 80.7% and specificity 97.9%). The combination of CML and HA shows an AUC of 0.932; 95%-CI 0.888–0.962; sensitivity 82.6%; and specificity 95.8%. Conclusions: Our data suggest that serum levels of CML could provide a supplementary diagnostic marker for advanced stages of liver cirrhosis. However, the quality of interaction needs further investigation.