Introduction
Cardiovascular diseases (CVDs) are the primary cause of death worldwide: it is approximated that 17.5 million people die from CVDs every year, and this makes CVDs accountable for more than one-fourth of the total global deaths.1 There is a considerable amount of evidence to show that obesity is one of the strongest risk factors associated with the development of MI. Obesity is characterized by inflammation that is related to other disorders, too.2Blood vessel inflammation plays a vital role in the initiation of plaques, their progression, and fibrous capture, which causes the formation of local thrombus and leads to hypoxia-related myocardial damage. In MI patients who have thrombus, the infarction-related arteries often exhibit endothelial dysfunction. In such vessels, inflammatory cytokines, such as interleukin-6 (IL-6), and its related signaling protein C-reactive protein (CRP), are found at high levels.3 Additionally, epidemiological research, as well as meta-analytical studies, have reported a linkage between the IL-6 and CRP levels in heart diseases, even among healthy males and females. Both markers have been linked with an augmented risk of mortality, especially in patients with unstable coronary artery disease (CAD).4, 5 In particular, circulating IL-6 is considered as an important pro-atherogenic cytokine, and its level is an independent predictor of cardiovascular mortality.6
High serum levels of IL-6, as well as other cytokines, are associated with poor clinical outcomes in hospitalized patients who have unstable angina or ST-elevated myocardial infarction (STEMI).7Moreover, multiple diseases that commonly lead to death among the elderly might stimulate or sustain a systemic inflammatory state that can be detected via a rise in IL-6 levels and other pro-inflammatory cytokines.8 In addition, IL-6 is one of the major cytokines involved in the production of acute-phase proteins, which show elevated levels in clinical conditions such as tissue injury caused by infections, tumors, ischemic disorders, and trauma.9Exploring the correlation of IL-6 with other important clinical parameters in these pathophysiologic events might shed light on the underlying inflammatory mechanisms and their association with an increased risk of mortality.9
High-sensitivity CRP (hs-CRP) has been shown to be a biomarker for vascular risk in atherothrombosis.10 hs-CRP has also been shown to be a prognostic marker in acute coronary syndrome patients, but it has poor specificity. In fact, it may be more useful as a prognostic marker when used in combination with IL-6, which has been reported to be a marker of inflammation, localized coronary plaques, and atherosclerotic plaques,11 and has also been reported to be significantly associated with inflammatory plaques in acute coronary syndrome patients.12 A combination of clinical parameters, such as CRP, IL-1,and IL-6, has shown promise as a target for anti-inflammatory agents used for atheroprotection.13 In the context of involvement of IL6 and CRP in the process of MI, this study was designed to determine the correlation of different parameters of cardiovascular risk with serum IL-6 and hsCRP levels in patients with MI.