Effect of Acute Surgical Stress on Serum Ghrelin Levels

BACKGROUND Ghrelin is an appetite hormone that influences the gastrointestinal function and regulates energy metabolism. Growing evidence also suggests that this hormone plays a central role in immune modulation. Each surgical operation is followed by a series of inflammatory and metabolic changes that constitute the stress response. The aim of our study is to evaluate the effect of stress during different types of abdominal surgery in ghrelin serum levels. METHODS An overall of 25 patients were prospectively allocated in two groups based on the type of surgical operation. Group A (n = 10) patients were scheduled to undergo cholecystectomy, whereas Group B (n = 15) patients underwent colectomy. Serum ghrelin concentrations were evaluated in each patient preoperatively, after the induction of general anesthesia and tracheal intubation, one and five hours after the beginning of surgery and the morning of the first and second postoperative day. RESULTS In both groups serum ghrelin concentrations reached their peak level at 24 hr (Group A: 8.4 ± 3.4 ng/mL; Group B: 7.4 ± 1.8 ng/mL) and these values were significantly higher than those in the preoperative period (Group A: 5.0 ±1.5 ng/mL; Group B: 4.8 ± 0.6 ng/mL) (P < 0.05). Forty eight hours after surgery the levels of ghrelin returned to their preoperative status. Patients' gender, age, ASA score and type of surgical procedure did not influence the serum ghrelin levels. CONCLUSIONS Serum ghrelin concentration appears to elevate in response to surgical stress. Future studies are needed to improve comprehension of the mechanisms underlying responses of this hormone to acute surgical stress and to evaluate their possible clinical implications.