The Neuroendocrine and Metabolic Outcomes of Bariatric Surgery Depend on Presurgical Control over Eating.

BACKGROUND: The outcomes of bariatric surgery are very irregular and mostly unpredictable. The search for variables of predictive value is encouraged to help preventing therapeutic failures. OBJECTIVE: We aimed to confirm the hypothesis that preexisting eating behaviors could predict neuroendocrine and metabolic outcomes of gastric bypass surgery in morbidly obese subjects. METHODS: Twenty-one morbidly obese patients from the Bariatric Surgery Program of our hospital were selected according to the specific inclusion and exclusion criteria for this study. The subjects filled out a validated questionnaire to quantify the "loss-of-control" (LC) dimension of food craving and provided serum samples at the onset of the study and 1 year after gastric bypass surgery. Hematological, metabolic, and hormonal variables were studied by conventional clinical tests and enzyme immunoassays and checked for correlations with LC both before and after surgery. RESULTS: Those patients that had exhibited worse eating control at the beginning of the study experienced a better metabolic response 1 year after surgery in terms of reduction of serum insulin, HOMA1-IR, HOMA2-IR, and vitamin D1; all these variables were inversely correlated with presurgical LC. Serum brain-derived neurotrophic factor (BDNF) levels showed the same tendency; in fact, BDNF significantly decreased only in those patients with worse eating control. CONCLUSIONS: Problematic eating behaviors may predict a better response of insulin resistance and a specific reduction of serum BDNF in morbidly obese patients after gastric bypass surgery.

Proteomic Identification of Biomarkers Associated with Eating Control and Bariatric Surgery Outcomes in Patients with Morbid Obesity.

BACKGROUND: The current therapeutics of morbid obesity could be significantly improved after the identification of novel biomarkers associated with the food addiction endophenotype of obesity and with bariatric surgery outcomes. METHODS: We applied differential expression proteomics and enzyme-linked immunosorbent confirmatory assays to identify (a) proteins that varied according to loss of control over eating in morbidly obese patients and (b) proteins that varied between normoweight controls and patients before and 1 year after bariatric surgery. RESULTS: Clusterin was the only protein that consistently varied according to eating control in patients. Patients showed increased levels of serum amyloid P protein, apolipoprotein A4, serotransferrin, complement factors B and C3 and haptoglobin with respect to controls; the levels of all these proteins tended to return to control values 1 year after surgery. In contrast, apolipoprotein A1 and transthyretin were initially downregulated in patients and were scarcely changed by surgery. Leucine-rich alpha-2-glycoprotein was markedly increased in patients only after surgery. CONCLUSIONS: Clusterin could be of interest as a putative biomarker for food addiction diagnosis in people with morbid obesity. In addition, postsurgical normalization of the proteins initially dysregulated in obese subjects might help monitor clinical improvements after surgery, while lasting or newly detected alterations (i.e., those affecting transthyretin and leucine-rich alpha-2-glycoprotein) could reflect partial refractoriness and/or contribute to the early prediction of clinical problems.