The Influence of Obesity on Postoperative Inflammatory Cytokine Levels

Obesity is a chronic inflammatory state and adipose tissue serves as a source of inflammatory mediators. This study compared plasma levels of the proinflammatory cytokines interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α) in 20 morbidly obese patients (group O) undergoing laparoscopic Roux-en-Y gastric bypass surgery and in 20 non-obese control patients (group C) undergoing laparascopic gastrectomy. Blood was sampled preoperatively and at 3 and 24 h postoperatively. Postoperative IL-6 levels increased significantly in both groups, but were significantly lower in group O than in group C. Age- and anaesthetic time-adjusted IL-6 levels showed a significant increase at 24 h postoperatively compared with preoperative values in both groups; changes were significantly greater in group C. TNF-α levels did not change significantly over time, but were significantly lower in group O at 3 h postoperatively compared with group C. In conclusion, postoperative changes in IL-6 and TNF-α levels in morbidly obese patients were lower than in non-obese patients. Adipose tissue appears not to contribute to the acute postoperative inflammatory response.