Perioperative response of leptin and the tumor necrosis factor alpha system in morbidly obese patients. Influence of cortisol inhibition by etomidate

Background: Leptin, tumor necrosis factor alpha (TNF alpha) and soluble TNF alpha receptors are secreted by the adipose tissue. Surgery induces a comp lex cytokine and neurohormonal response. The aim of our study was to invest igate the perioperative response of leptin and the TNF alpha system in morb idly obese patients submitted to gastroplasty, and the possible involvement of cortisol in their responses. Methods: Serum cortisol, adrenocorticotropic hormone (ACTH), leptin, TNF al pha and soluble TNF alpha receptor I were measured in 22 morbidly obese wom en (11 anesthetized with thiopental and 11 with etomidate, a well known inh ibitor of cortisol synthesis). Samples were collected before anesthesia ind uction, just before surgical incision, and 2, 4, 6, 12, 24 and 48 h after t he start of surgery. Results: Baseline serum leptin correlated with body mass index (r=0.567, P= 0.007). Baseline serum leptin and TNF alpha were higher than normal. Cortis ol release was inhibited in the etomidate group with a subsequent higher st imulation of ACTH release. A statistically significant decrease in serum le ptin levels was observed in both groups at 2, 4, 6 and 48 h, compared with basal values. A similar decrease in serum TNF alpha levels was observed in both groups, but the decrease reached significance only in the etomidate gr oup. Serum soluble TNF alpha receptor I did not decrease. No differences we re found between the two groups in leptin, TNF alpha or soluble TNF alpha r eceptor I concentrations at any time. Clonclusion: Serum leptin and TNF alpha levels decrease in obese patients d uring gastroplasty. Transitory inhibition of cortisol release does not alte r this response.