Effect of massive weight loss induced by bariatric surgery on serum levels of interleukin-18 and monocyte-chemoattractant-protein-1 in morbid obesity

Background: Morbid obesity is associated with insulin resistance (IR), chronic inflammation and premature atherosclerosis. Since vascular inflammation may contribute to the increased risk of cardiovascular morbidity and mortality of these patients, we studied circulating Interleukin-18 (L-18) and monocyte-chemoattractant-protein-1 (MCP-1) levels in 37 patients with morbid obesity before and after significant weight loss induced by bariatric surgery and their preoperative and postoperative associations with C-reactive protein (CRP) and IR-associated factors. Methods: High sensitivity assays were used to measure concentrations of fasting CRP, IL-18 and MCP-1. Differences between patients before and after bariatric surgery were analyzed by Student's paired t-test. To investigate the associations of the observed reductions of values, delta of parameters were calculated and preoperative, postoperative and delta data were tested by univariate and multivariate linear regression. Results: After a mean follow-up period of 26.5 months and a massive weight loss of 35 kg induced by bariatric surgery, circulating IL-18 levels decreased by 37% (P < 0.001) and circulating MCP-1 levels by 47% (P < 0.001). Multiple linear regression of delta values of IL-18 showed that only 2-hour glucose (P = 0.008) remained independently and significantly associated with IL-18, whereas multiple linear regression analysis of delta values of MCP-1 revealed that only delta of HOMA-IR (P < 0.001) remained independently and significantly associated with MCP-1, respectively. Conclusions: Because both biomarkers have been shown to play an important role in the development and progression of atherosclerosis, the observations presented in this study could be of clinical relevance for morbidly obese patients undergoing bariatric surgery.