Circulating Ghrelin in Patients Undergoing Elective Cholecystectomy

Abstract

Secreted predominantly from the stomach (1), ghrelin is a peptide identified in 1999 as an endogenous ligand of the growth hormone (GH) secretagogue receptor located on the pituitary gland, thus fulfilling the criteria of a brain–gut peptide (2)(3). The brain–gut axis serves as an effector of anabolism by regulating growth, feeding, and metabolism via vagal afferent-mediating ghrelin signaling (2)(4). The role of ghrelin as a brain–gut peptide emphasizes the significance of afferent vagal fibers as a major pathway to the brain, serving the purpose of maintaining physiologic homeostasis (2)(4). The importance of ghrelin as a “hunger hormone” with orexigenic effects mediated by the hypothalamic peptides, agouti-related peptide, and neuropeptide Y, and the fact that it is the most potent peripheral signal of diminishing energy stores, implies that ghrelin release might be the most important of the many redundant mechanisms ensuring human survival in times of famine (4). However, the wide tissue distribution of ghrelin suggests that it may have other functions as well (5). Further characterization of the functions of ghrelin is fundamental to discovering new approaches to the diagnosis and treatment of different disease entities, including those related to the catabolic response to surgical trauma (2). In this preliminary study, we report the pattern of ghrelin secretion in different perioperative periods in patients undergoing elective cholecystectomy. Thirty patients [17 females; age range, 20–45 years; body mass index (BMI), 18–25 kg/m2] with ultrasound-confirmed cholecystolithiasis undergoing elective cholecystectomy via laparoscopy or laparotomy at the Surgical Department at the Hospital Umberto I° of Rome were recruited to the study. All patients presented a low surgical risk (American Society of Anesthetists’ score 1 or 2). Patients with a diagnosis of choledocholitiasis, jaundice, acute cholecystitis, and pancreatitis; those with a history of metabolic, endocrine, hepatic, cardiac, …