Interleukin-6 correlates with endothelial dysfunction in young post-myocardial infarction patients

Background: The estimation of coronary risk based on consideration of classical risk factors is insufficient in young patients with myocardial infarction who have low expressions of classical risk factors. Endothelial dysfunction (ED) and markers of vascular inflammation may be more appropriate for risk estimation. The relations among ED and inflammation markers in such patients have not yet been explored. Patients and Methods: Twenty-one patients (on average 44 years old) in the stable phase after myocardial infarction, with low expressions of risk factors, were included in the study. The control group consisted of 25 healthy age-matched males. ED was estimated by ultrasound measurement of the endothelium-dependent dilatation of the brachial artery. The following inflammation markers were measured: hsCRP, interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-alpha), ICAM-1, VCAM-1, selectin-P and selectin-E. Results: Patients had a significantly reduced level of endothelium-dependent vasodilatation (5.6 +/- 3.5 vs. 8.8 +/- 6.5%, p < 0.05), and an increased level of IL-6 (3.2[1.5-8.4] vs. 1.4 [0.9-2.3] ng/ml; p < 0.01). All other inflammation markers were comparable to controls. We found a significant negative correlation between ED and the levels of IL-6 (r = -0.54, p = 0.012). Conclusion: It appears that IL-6 is the most valuable circulating marker of ED, and consequently a useful marker of coronary risk.