The postoperative stress response and its reflection in cytokine network and leptin plasma levels

The objective of the present report was to clarify the postoperative stress response of some inflammatory markers, namely of proinflammatory cytokines and leptin levels during uncomplicated postoperative periods. The results were compared with the dynamics of these parameters during intraabdominal sepsis. We followed 20 patients after a planned resection of colorectal cancer in stage Ib-IV with uncomplicated healing and 13 obese men after laparoscopic nonadjustable gastric banding. These were compared to 12 patients with proven postoperative sepsis. The control group consisted of 18 healthy men. The observed parameters included serum levels of cytokines, tumor necrosis factor-alpha (TNF alpha), interleukin-1 beta (IL-1 beta), interleukin-1 receptor antagonist (IL-1ra), IL-6, IL-8, soluble receptor of interleukin-2 (sIL-2R) and leptin. It was found that during the first 24 h after resection there was a significant increase in the serum concentration of IL-6 up to 1125 +/- 240 ng/l, which declined within the next 48-72 h. Serum concentration of TNF alpha was highest 18-24 h after resection (205 +/- 22 ng/l) and after banding (184 +/- 77 ng/l). IL-1 beta had a stable serum concentration without significant elevation. Serum concentration of IL-8 after resection rose to 520 +/- 200 ng/l after 36-48 h. Maximal cytokine levels after gastric banding were quantitatively lower (IL-6 414 +/- 240 ng/l, TNF alpha 184 +/- 77 ng/l) than after resection. We found significant elevation of plasma leptin concentration (32 +/- 10 ng/ml) 24 h after banding compared with preoperative values (18 +/- 5 ng/ml, p < 0.05). Leptin levels 48 and 72 h after banding rapidly returned to the level before operation. During abdominal surgery leptin shows to be an acute phase reactant. Proinflammatory cytokines can be main regulatory factors of leptin during this period. Significant correlation between leptin and TNF alpha (similarly demonstrated by other authors in models of bacterial inflammation) indicates that TNF alpha can be the crucial regulator of leptin generation in the early postoperative period. On the basis of our results we recommend to observe IL-6 and IL-8 at 24-72 h after the surgery in patients with a high risk of early postoperative septic complications.