[Role of IL-6 and its -174G>C polymorphism in weight management and in the metabolic comorbidities associated with obesity].

Obesity and its comorbidities have been associated with a low grade proinflammatory state, in which the adipose tissue seems to be involved. In fact, this tissue produces different proinflammatory cytokines, such as IL-6 and others. High circulating concentrations of IL-6 have been related to high body mass index, to diabetes mellitus type 2, to lipid abnormalities and to high blood pressure. There are some studies, which reported a relationship between IL-6 and energy metabolism, so this cytokine and its -174G>C gene polymorphism could be factors involved in the development of obesity. Different studies have associated the G allele of the IL-6 gene with obesity, with insulin resistance and with different cardiovascular risk factors. However, other published reports have associated the C allele of this gene to these metabolic disturbances and pathologies. This paper reviews recently published evidences about IL-6 and its physiopathological involvement in obesity and comorbidities, with emphasis on the role of the -174G>C polymorphism in the aetiology of these disturbances, in which obesity is a major risk factor.