RESUMO
The prevalence of metabolic syndrome is high and will likely increase further as the obesity epidemic accelerates. Leptin is a peptide hormone mostly derived from adipose tissue that promotes negative energy balance. Hyperleptinemia is common in obesity and reflects increased fat mass and leptin resistance. Nevertheless, leptin resistance might not be complete as several actions of leptin, like cardiovascular sympathetic activation, might be preserved in obese subjects that are resistant to the metabolic actions of leptin (i.e. selective leptin resistance). Leptin may contribute to elevated blood pressure, hyperglycemia, dyslipidemia, pro-thrombotic and proinflammatory states found in metabolic syndrome. Notably, the renal and sympathetic actions of leptin appear to play a major role in the pathogenesis of hypertension related to obesity and the metabolic syndrome. Furthermore, the lipotoxic effect of leptin resistance is thought to be a major determinant of insulin resistance and may increase the risk of type 2 diabetes