ABSTRACT
BACKGROUND: Interleukin-18 (IL-18), a proinflammatory and proatherogenic cytokine, has been associated with type 2 diabetes, metabolic syndrome, stroke and coronary artery disease. Some studies have indicated that the IL-18 promoter -137 G/C polymorphism seems to be associated with changes in the IL-18 expression and may contribute to the development of cardiovascular disease (CVD). The aim of this study was to evaluate the association between -137 G/C polymorphism and the levels of IL-18, biochemical markers for cardiovascular disorders, anthropometric profile and cardiovascular disease in Brazilian patients with type 2 diabetes (T2DM). DESIGN & METHODS: Study subjects comprised 125 T2DM patients undergoing follow-up at a reference endocrinology service in northeastern Brazil. The -137G/C polymorphism in the IL-18 gene and serum IL-18 levels were determined by using allele-specific polymerase chain reaction (PCR) and enzyme-linked immune assay (ELISA), respectively. The anthropometric parameters were assessed using a Body Composition Monitor with Scale, and the laboratory data were measured using an automatic analyzer as well as spectrophotometric analysis. RESULTS: The genotype distribution of IL-18 -137 G/C genetic polymorphism was significantly different among T2DM patients with and without CVD. The results show an association between the CC genotype of -137G/C polymorphism and CVD in T2DM patients (p < 0.001). Serum levels of IL-18 were significantly higher in CC carriers (843.1 pg/mL) compared with GG or GC carriers (303.6 pg/mL and 292.0 pg/mL, respectively). In addition, the present study showed that carriers of the CC genotype also had significantly higher concentrations of creatinine and albuminuria than carriers of the GG or GC genotypes (p < 0.05 in both). CONCLUSION: These results suggest that Brazilian T2DM patients with the CC genotype seem to show a predisposition to CVD, as well as an elevation in markers of renal function.