Changes in serum interleukin-6 and high-sensitivity C-reactive protein levels in patients with acute coronary syndrome and their responses to simvastatin

The role of inflammation in acute coronary syndrome (ACS) and the mechanism by which statin treats ACS is explored. Serum high-sensitivity C-reactive protein (hs-CRP) and interleukin-6 (IL-6) levels were measured in 50 patients with ACS [including 30 cases with unstable angina (UA) and 20 patients with acute myocardial infarction (AMI)], 34 patients with stable angina (SA), and 30 controls. Patients in the ACS group were randomly assigned to a simvastatin group (including a simvastatin AMI subgroup, n = 11 and a simvastatin UA subgroup, n = 14) and a routine group (including a routine AMI subgroup, n = 9 and a routine UA subgroup, n = 16). The simvastatin group was given simvastatin 20 mg/day and the routine group a placebo. After a 3-week follow-up, serum hs-CRP, IL-6 levels, and serum lipid concentrations were measured again. Both serum IL-6 and hs-CRP levels were significantly higher in the ACS group (including the UA and AMI subgroups) than in the SA and control groups (P < 0.001). After 3 weeks of treatment with simvastatin, the serum IL-6, hs-CRP, total cholesterol, and low-density lipoprotein cholesterol levels were decreased significantly in the simvastatin group (P < 0.001), but no significant changes were observed in the routine group. No relationship was observed between the rate of decrease of serum IL-6 or hs-CRP and serum lipids levels. The hs-CRP level showed a significant correlation with IL-6 by Spearman's rank correlation analysis (P < 0.01). Inflammation plays an important role in the initiation of ACS. Simvastatin possesses an anti-inflammatory effect, independent of its lipid-lowering action, which may play an important role in the early treatment of ACS.