Evaluation of a Classifier Based on Calprotectin Concentration and Advanced Glycation End-Product Receptor as a Potential Biomarker for Abdominal Aortic Aneurysm

Calprotectin is a calcium-binding protein involved in inflammatory processes. In the context of abdominal aortic aneurysm (AAA), elevated levels of calprotectin may indicate immune system activation and chronic inflammation, which are among the mechanisms contributing to the development and progression of AAA. The receptor for advanced glycation end-products (RAGE) is a receptor that binds various ligands, including advanced glycation end-products formed during the glycation of proteins and lipids under oxidative stress conditions. Activation of RAGE is associated with inflammatory processes, oxidative stress, and tissue remodeling, which may contribute to the weakening of the aortic wall and aneurysm formation. The main objective of this study was to evaluate the effectiveness of both biomarkers in distinguishing patients with abdominal aortic aneurysm. A total of 27 patients with diagnosed AAA were included in the study. The control group consisted of 27 patients without AAA. Plasma levels of calprotectin and sRAGE were measured in both groups. Statistical analysis included the Shapiro-Wilk test, Mann-Whitney U test, and the Hosmer-Lemeshow (H-L) test. The likelihood of having AAA was found to be over one hundred times greater in individuals classified into the AAA group based on a decision tree model using calprotectin and sRAGE levels, compared to those classified into the no-AAA group. Calprotectin concentration was identified as a stronger predictor of AAA than sRAGE. The optimal cut-off value for plasma calprotectin was determined as ≥1136 ng/mL, yielding a sensitivity of 81.5% and a specificity of 100.0% for discriminating AAA patients from controls. It may be beneficial in future studies to explore non-invasive approaches, such as measuring calprotectin levels in stool and sRAGE in urine, as a potential screening method for AAA. Monitoring the concentrations of these biomarkers in bodily fluids, as a non-invasive method, could support screening efforts for AAA.