Weight regain was observed within 24 months after surgery in approximately 50% of patients. Both weight regain and surgical failure were higher in the superobese group. Studies in regard to metabolic and hormonal mechanisms underlying weight regain might elucidate the causes of this finding.

The TyG index was evaluated as a surrogate method for estimation of insulin resistance (IR). TyG index correlated with adiposity, metabolic and atherosclerosis markers related to IR and presented a moderate degree of agreement with hyperglycemic clamp. TyG index represents an accessible tool for assessment of IR in clinical practice.

Neck circumference measurements are an alternative and innovative approach for determining body fat distribution. The NC is positively associated with MetS risk factors, IR and VF, with established cut-off values for the prediction of MetS and IR.

Objective: To investigate cut-off values for HOMA1-IR and HOMA2-IR to identify insulin resistance (IR) and metabolic syndrome (MS), and to assess the association of the indexes with components of the MS. Methods: Nondiabetic subjects from the Brazilian Metabolic Syndrome Study were studied (n = 1,203, 18 to 78 years). The cut-off values for IR were determined from the 90 th percentile in the healthy group (n = 297) and, for MS, a ROC curve was generated for the total sample. Results: In the healthy group, HOMA-IR indexes were associated with central obesity, triglycerides and total cholesterol (p < 0.001).

Ghrelin was inversely related to leptin concentrations. Presence of diabetes did not affect the ghrelin pattern. Reduced production of ghrelin after gastric bypass could be partly responsible for the lack of hyperphagia and thus for the weight loss.

OBJECTIVEInflammation and dysfunction of the hypothalamus are common features of experimental obesity. However, it is unknown whether obesity and massive loss of body mass can modify the immunologic status or the functional activity of the human brain. Therefore, the aim of this study was to determine the effect of body mass reduction on brain functionality.RESEARCH DESIGN AND METHODSIn humans, changes in hypothalamic activity after a meal or glucose intake can be detected by functional magnetic resonance imaging (fMRI). Distinct fMRI analytic methods have been developed to explore changes in the brain’s activity in several physiologic and pathologic conditions. We used two analytic methods of fMRI to explore the changes in the brain activity after body mass reduction.RESULTSObese patients present distinct functional activity patterns in selected brain regions compared with lean subjects. On massive loss of body mass, after bariatric surgery, increases in the cerebrospinal fluid (CSF) concentrations of interleukin (IL)-10 and IL-6 are accompanied by changes in fMRI patterns, particularly in the hypothalamus.CONCLUSIONSMassive reduction of body mass promotes a partial reversal of hypothalamic dysfunction and increases anti-inflammatory activity in the CSF.

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Obesity and caloric overfeeding are associated with the defective regulation of autophagy in the adipose tissue. The studies in obese-diabetic subjects undergoing improved metabolic control following calorie restriction suggest that autophagy and inflammation are regulated independently.