RESUMO
Interleukin -18 [IL-18] is a recently evaluated cytokine synthesized by Kupffer cells. It has been shown to activate macrophages and has direct proinflammatory activities of many cells including inflammatory and vascular cells. This study aimed to evaluate the clinical implication of serum levels of IL-18 among patients with ACS in comparison with other markers of chronic inflammation and to assess the relation of IL-18 serum levels with various conventional cardiovascular risk factors, its role in plaque instability and myocardial dysfunction. The present hospital based observational study was conducted on 55 patients with acute coronary syndromes [ACS], admitted to the Coronary Care Unit of El-Minia University Hospital in the period from May 2004 to January 2005. These patients were divided into two groups. GROUP I: It consisted of 30 patients with acute myocardial infarction [AMI]. GROUP II: It consisted of 25 patients with unstable angina [UA]. For comparison purposes two additional groups were added whose individuals were age and sex matched to patient's groups I and II. GROUP III: It consisted of 1.5 patients with stable angina [SA] to form coronary control group. GROUP IV: This group consisted of 15 apparently healthy subjects to form the non-coronary control group. Full clinical examination was performed with specific emphasis on body mass index [BMI] and blood pressure measurement. Abdominal ultrasound, electrocardiogram [ECG], and echocardiography were done. Laboratory investigations were performed, including blood sugar, complete lipogram, renal function tests, liver function tests, cardiac enzymes, complete blood picture, erythrocyte sedimentation rate, C-reactive protein [CRP], nitric oxide [NO], fibrinogen, and IL-18. The current study reported increase serum levels of IL-18 in ACS group than in healthy volunteers as whole and even when stratified as AMI and UA groups. Furthermore, the current study revealed increase serum levels of IL-18 in ACS group than in SA group, as a whole and even when stratified as AMI and UA groups. The percentage of CRP positive patients were significantly higher in ACS, UA, and AMI groups than coronary and non coronary control groups. There were significant positive correlation between serum levels of IL-18 and each of the following: fibrinogen, OX-LDL, and NO among ACS, AMI, and UA groups. Also, it revealed significant positive correlation between serum levels of IL-18 and each of the following: cholesterol, triglycrides, and LDL-C in ACS and UA groups; however, there was significant positive correlation between its serum levels and each of the following cholesterol and LDL-C in AMI group. Serum levels of IL-18 in patients with EF% < 45% were statistically significant higher than its serum levels in patients with EF% > 45% in ACS, and AMI groups, and near significance in UA group. Serum levels of IL-18 were higher in ACS, UA, and AMI groups versus healthy volunteers. The proinflammatory role of IL-18 in the initiation and progression of atherosclerosis was proved in the present study by the presence of positive significant correlation between serum levels of IL-18 and some markers of chronic inflammation as fibrinogen, CRP and NO