A prospective study of genetic markers of susceptibility to infection and inflammation, and the severity, progression, and regression of coronary atherosclerosis and its response to therapy

Abstract

Inflammation plays a key role in susceptibility to coronary atherosclerosis and response to therapy. A diverse array of factors modulates inflammation, including interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and CD14 receptors on the surface of macrophages. Genes encoding for inflammatory markers have variants that regulate their expression and are potential risk factors for atherosclerosis. We prospectively analyzed the possible association of CD14 -260C/T, TNF-alpha -308G/A, and IL-6 -174G/C variants, located in the promoter regions, with the severity, progression, and response to therapy of coronary atherosclerosis in a well-characterized cohort. We studied 375 subjects enrolled in the Lipoprotein and Coronary Atherosclerosis Study (LCAS). Genotypes were determined by polymerase chain reaction (PCR) and restriction mapping. Fasting plasma lipids and quantitative coronary angiograms were obtained at baseline and 2.5 years following randomization to fluvastatin or placebo. Distributions of genotypes were--for CD14: 100 CC, 184 CT, and 86 TT; IL-6: 152 GG, 153 GC, and 62 CC; and TNF-alpha: 244 GG, 110 GA, and 17 AA. The CD14 CC genotype was associated with incidence of new coronary occlusion (P=0.026); TNF-alpha AA genotype with history of myocardial infarction (MI, P=0.04), and A allele with total occlusions at baseline (P=0.027), and systolic blood pressure (P=0.046); and IL-6-174 CC genotype with baseline minimum lumen diameter (P=0.043) and reduction in lipoprotein(a) with fluvastatin (P=0.03). Otherwise, no association between the genotypes and the biochemical, angiographic, and clinical phenotypes was detected, and neither were genotype-treatment interactions. Functional variants of CD14 -260C/T, TNF-alpha -308G/A, and IL-6 -174G/C, implicated in the susceptibility to infection, are unlikely to confer major risk for susceptibility to coronary atherosclerosis and its progression or response to therapy in the LCAS population.