Inflammatory markers associated with abdominal aortic aneurysm

Inflammation with leukocytic infiltration, degradation of extracellular matrix (ECM), and depletion of vascular smooth muscle cells (VSMC) are pathological hallmarks of abdominal aortic aneurysm (AAA). The aim of this study was to further evaluate relationships between AAA and inflammatory biomarkers, interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α), endothelin-1 (ET-1) and soluble urokinase-type plasminogen activator receptor (suPAR), by comparing levels in 65-year-old men with and without AAA at ultrasound screening. We also evaluated whether any biomarker can independently predict AAA at screening, and clarified potential correlations between aortic diameter and blood levels of these biomarkers.

There were significant (p ≤ 0.05) differences between subjects with and without AAA for the following variables: p-leukocyte count (TLC) (p<0.001), p-homocysteine (p<0.001), p-TNF-α (p = 0.023), p-IL-6 (p<0.001), p-ET-1 (p = 0.002), p-suPAR (p<0.001), ankle brachial index (ABI) (p<0.001), plasma (p)-creatinine (p = 0.049), p-total cholesterol (p<0.001), p-high density lipoprotein (HDL) (p<0.001) and low density lipoprotein (LDL) cholesterol (p = 0.001), smoking habits (p<0.001), and use of antihypertensive (p<0.001) and lipid-lowering (p = 0.001) drugs. When the above variables were stepwise excluded in a logistic regression model, only p-IL-6 (p = 0.002), p-homocysteine (p = 0.015), p-HDL (p = 0.004), ABI in the right (p = 0.005) and left (p = 0.094) leg, smoking habits (p = 0.003), and antihypertensive drug use (p = 0.045), differed between groups. Significant correlations with aortic diameter existed for p-TNF-α (p = 0.028), p-IL-6 (p<0.001), p-ET-1 (p = 0.002) and p-suPAR (p<0.001) in the entire study population, and for p-TNF-α (p = 0.023), p-ET-1 (p = 0.009) and p-suPAR (p = 0.001) among men with AAA.

Several inflammatory biomarkers were significantly elevated and correlated with aortic diameter among 65-year old men with AAA at ultrasound screening. IL-6, homocysteine and use of antihypertensive medication remained elevated in the logistic regression model, together with known risk markers for AAA such as smoking and signs of atherosclerosis.