Cytokine-Family Biomarker Candidates for Small Abdominal Aortic Aneurysm Identified via Integrated mRNA and Protein Expression Profiling

Abdominal aortic aneurysm (AAA) is a chronic vascular disease characterized by localized dilatation of the abdominal aorta. This condition is frequently underdiagnosed and carries a high mortality rate (65–85%) due to aneurysm rupture. Although numerous candidate biomarkers have been identified for AAA, none have been successfully implemented in clinical diagnostic procedures for AAA screening. This highlights the critical need for the discovery and validation of reliable biomarkers to improve early detection and risk stratification in AAA. Therefore, in our study, we aimed to identify small AAA (sAAA) biomarker candidates among the key cytokines and receptors of IL-1, IL-6, IL-8, IL-10, and IL-17 families on gene expression and plasma protein levels. Comparative analysis was conducted between a group of 100 men with sAAA (<54 mm in diameter) and a group of 100 men without AAA. Expression profiles of the analyzed cytokines and their receptors were obtained in peripheral blood mononuclear cells using real-time PCR, while plasma levels of selected encoded proteins were determined using ELISA. The mean expression of IL10RA, IL17RA, CXCL8, and IL1B, as well as the plasma levels of IL-17A, were significantly different between the sAAA and Control groups, with CXCL8 and IL1B exhibiting a strong mutual correlation. The diagnostic model incorporating these biomarker candidates and D-dimer levels showed a fair classification performance (ROC-AUC = 0.756), with a sensitivity and specificity of approximately 0.7. The selected biomarker candidates were functionally associated with fibroblast activation, neutrophil chemotaxis, T-helper cell function, and cell adhesion and proliferation. Cytokines selected as biomarker candidates represent a promising field for further studies on the identification of diagnostic targets for the early detection of AAA.