RESUMO
OBJECTIVES: Since complement system has been recently associated with metabolic and cardiovascular diseases, and closely related to insulin resistance, we investigated the association of plasma complement factor 3 (C3) and factor 4 (C4) with insulin sensibility and weight loss after bariatric surgery. METHODS: Serum levels of C3, C4, total cholesterol, triacylglycerol, HDL-cholesterol, LDL-cholesterol and homeostatic model assessment (HOMA-IR) measurements were assessed in morbidly obese patients before and after bariatric surgery, including a 6-month follow-up period, as well as a comparison with a lean group. RESULTS: Weight loss decreased body mass index (BMI), serum triacylglycerol, and increased serum HDL-cholesterol and insulin sensitivity, as expected. C3 and C4 were significantly higher in obese individuals when compared to lean subjects (p<0.001). In addition, C3 and C4 positively correlated with BMI and HOMA-IR, however, only C3 were significantly decreased 6months after surgery. CONCLUSION: C3 was strongly associated with insulin sensitivity after bariatric surgery.