Are early clinical effects of cholesterol lowering mediated through effects on inflammation?

In a randomized, double-blind trial in 3086 patients with unstable angina pectoris or non-Q wave myocardial infarction we investigated if 80 mg of atorvastatin daily could improve outcome of cardiovascular events during a short period of time (16 weeks) compared with placebo. Baseline LDL cholesterol was 3.2 mmol L-1 (124 mg dL-1) and decreased by 40% to 1.9 mmol L-1 (72 mg dL-1) during atorvastatin treatment. The primary endpoint, which was a composite of death, non-fatal acute myocardial infarction, cardiac arrest with resuscitation or recurrent symptomatic myocardial ischaemia with objective evidence and requiring emergency rehospitalization occurred in 228 patients (14.8%) in the atorvastatin group and 269 patients (17.4%) in the placebo group. The relative risk was 0.84 and 95% confidence interval was 0.70-1.00 (P = 0.048). Thus for patients with acute coronary syndromes, lipid-lowering therapy with high dose atorvastatin reduces recurrent ischaemic events in the short-term. A possible mechanism behind this rapid clinical effect induced by statin treatment is on inflammatory processes. Recent studies strongly suggest that acute T-cell activation is involved in the pathogenesis of unstable angina. In another study we investigated whether circulating T cells showed signs of activation in patients with stable angina pectoris (SA). Systemic venous blood samples were taken from 38 men with SA and 42 healthy controls. The T-cell receptor expression was assessed by three-colour flow cytometry using monoclonal antibodies against CD3,CD4, CD8, CD25 and human leucocyte antigen (HLA)-DR. Soluble interleukin-2 receptor (sIL-2R) was measured as the circulating form in serum. Levels of circulating CD3+ and CD4+ T cells tended to be higher in patients compared with controls. Patients were also shown to have a significant increase in CD4+ T cells expressing the activation markers CD25 (P < 0.05) and HLA-DR (P < 0.01). Furthermore, serum levels of sIL-2R were significantly higher (P < 0.001) in patients than in controls. We also observed that the T-cell response was more pronounced in patients without simvastatin treatment (n = 18) compared with simvastatin-treated patients (n = 20). In conclusion, our findings indicate that a continuous immune system activation takes place in patients with chronic angina pectoris, predominantly involving proliferation of CD4+ T cells. Statin treatment seems to be able to decrease this inflammatory response.

RCT Entities:   Population Interventions Outcomes