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Concept: Gastric bypass surgery

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Morbidly obese patients exhibit impaired secretion of gut hormones that may contribute to the development of obesity. After bariatric surgery there is a dramatic increase in gut hormone release. In this study, gastric and duodenal tissues were endoscopically collected from lean, and morbidly obese subjects before and 3 months after laparoscopic sleeve gastrectomy (LSG). Tissue morphology, abundance of chromogranin A, gut hormones, α-defensin, mucin 2, Na(+)/glucose co-transporter 1 (SGLT1) and transcription factors, Hes1, HATH1, NeuroD1, and Ngn3, were determined. In obese patients, the total number of enteroendocrine cells (EEC) and EECs containing gut hormones were significantly reduced in the stomach and duodenum, compared to lean, and returned to normality post-LSG. No changes in villus height/crypt depth were observed. A significant increase in mucin 2 and SGLT1 expression was detected in the obese duodenum. Expression levels of transcription factors required for differentiation of absorptive and secretory cell lineages were altered. We propose that in obesity, there is deregulation in differentiation of intestinal epithelial cell lineages that may influence the levels of released gut hormones. Post-LSG cellular differentiation profile is restored. An understanding of molecular mechanisms controlling epithelial cell differentiation in the obese intestine assists in the development of non-invasive therapeutic strategies.

Concepts: DNA, Gene expression, Developmental biology, Obesity, Cellular differentiation, Stomach, Tissue, Gastric bypass surgery

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Severely obese adolescents harbor numerous cardiovascular disease risk factors (CVD-RFs), which improve after metabolic and bariatric surgery (MBS). However, predictors of change in CVD-RFs among adolescents have not yet been reported.

Concepts: Medicine, Myocardial infarction, Blood vessel, Obesity, Cardiovascular disease, Physical exercise, Bariatric surgery, Gastric bypass surgery

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Many obese subjects suffer from an increased hedonic drive to consume palatable foods, i.e., hedonic hunger, and often show unfavorable dietary habits. Here, we investigated changes in the hedonic hunger and dietary habits after Roux-en-Y gastric bypass (RYGB) surgery.

Concepts: Nutrition, Obesity, Bariatric surgery, Gastric bypass surgery, Bariatrics, Duodenum, Surgical procedures, Beriberi

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OBJECTIVE: To explore public opinion regarding insurance coverage for obesity treatment among severely obese adolescents. DESIGN AND METHODS: The National Poll on Children’s Health was fielded to a nationally representative sample of US adults, January 2011. Respondents (n=2150) indicated whether insurance should cover specific weight management services for obese adolescents and whether private insurance and Medicaid should cover bariatric surgery. Sampling weights were applied to generate nationally representative results. Linear and logistic regression analyses were performed to assess associations. RESULTS: More respondents endorsed insurance coverage for traditional healthcare services (mental health 86%, dietitian 84%) than for services generally viewed as outside the healthcare arena (exercise programs 65%, group programs 60%). For bariatric surgery, 81% endorsed private insurance coverage; 55% endorsed Medicaid coverage. Medicaid enrollees, black, Hispanic, and low-income respondents had greater odds (p<0.05) of endorsing bariatric surgery coverage by Medicaid, compared to the referent groups (non-Hispanic white, income ≥ &Dollar;60K, private insurance). CONCLUSION: While public support for insurance coverage of traditional weight management services appears high, support for Medicaid coverage for bariatric surgery is lower and varies by demographics. If public opinion is a harbinger of future coverage, low-income adolescents could experience disparities in access to treatments like bariatric surgery.

Concepts: Regression analysis, Nutrition, Obesity, Overweight, Weight loss, Malnutrition, Bariatric surgery, Gastric bypass surgery

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Background  Roux-en-Y gastric bypass (RYGB) surgery is very effective in reducing excess body weight and improving glucose homeostasis in obese subjects. Changes in the pattern of gut hormone secretion are thought to play a major role, but the mechanisms leading to both changed hormone secretion and beneficial effects remain unclear. Specifically, it is not clear whether changes in the number of hormone-secreting enteroendocrine cells, or changes in the releasing stimuli, or both, are important. Methods  We estimated numbers of enteroendocrine cells after immunohistochemical staining in fixed tissue samples from rats at 10-11 months after RYGB. Key Results  Numbers of glucagon-like peptide-1 (GLP-1) (L-cells, co-expressing peptide YY (PYY)), cholecystokinin (CCK), neurotensin, and 5-HT-immunoreactive cells were significantly increased in the Roux and common limbs, but not the biliopancreatic limb in RYGB rats compared with sham-operated, obese rats fed high-fat diet, and chow-fed controls. This increase was mostly accounted for by general hyperplasia of all intestinal wall layers of the nutrient-perfused Roux and common limbs, and less to increased density of expression. The number of ghrelin cells in the bypassed stomach was not different among the three groups. Conclusions & Inferences  The findings suggest that the number of enteroendocrine cells increases passively as the gut adapts, and that the increased total number of L- and I-cells is likely to contribute to the higher circulating levels of GLP-1, PYY, and CCK, potentially leading to suppression of food intake and stimulation of insulin secretion. Whether changes in releasing stimuli also contribute to altered circulating levels will have to be determined in future studies.

Concepts: Nutrition, Insulin, Obesity, Bariatric surgery, Gastric bypass surgery, Bariatrics, Duodenum, Beriberi

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Observational studies suggest that bariatric surgery is the most effective intervention for achieving a significant and durable weight loss. In patients with type 2 diabetes, such surgery is often associated with remission of their diabetes. The mechanism(s) by which surgeries such as Roux-en-Y Gastric Bypass (RYGB) leads to favorable effects on glucose metabolism remain unknown. RYGB is associated with altered secretion of enteroendocrine hormones, leading to the belief that these hormones contribute to the improvement in insulin secretion and action as well as satiation after this procedure. However, it is important to consider the not insignificant effects of caloric restriction and the mechanical changes to the upper gut in determining the outcomes of such surgery.

Concepts: Insulin, Diabetes mellitus, Obesity, Surgery, Bariatric surgery, Gastric bypass surgery, Bariatrics, Duodenum

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INTRODUCTION: Obesity is a chronic disease associated with oxidative stress. Bariatric surgery for the treatment of obesity may affect biomarkers of oxidative stress. OBJECTIVES: The aim of the present study was to evaluate the effect of Roux-en-Y gastric bypass (RYGB) on blood markers of oxidative stress, such as vitamins C and E, β-carotene, reduced glutathione (GSH), catalase (CAT), ferric reducing antioxidant potential (FRAP), and thiobarbituric acid-reactive substances (TBARS). METHODS: A prospective controlled clinical trial was carried out. The participants were distributed into two groups: a control group (n=35), which was evaluated once, and a bariatric group (n=35), which was evaluated at baseline as well as 6, 12, and 24 months after surgery. RESULTS: After surgery, the BMI decreased from 47.05±1.46 to 30.53±1.14 kg/m (P<0.001), but 25.7% of the participants regained weight after 24 months. In relation to the baseline, postsurgery reductions were found in vitamin C (31.9±4.6%, P<0.001), β-carotene (360.7±368.3%, P<0.001), vitamin E (22.8±4.1%, P<0.001), GSH (6.6±5.2%, P=0.090), CAT (12.7±5.6%, P=0.029), and FRAP (1.2±3.8%, P=0.085) 2 years after RYGB. TBARS levels decreased after 12 months (71.6±2.9%, P<0.001) in relation to the baseline but increased by 195.0±28.2% between the 12th and the 24th month (P<0.001). CONCLUSION: The present findings show that oxidative stress returned 2 years after RYGB. Concentrations of vitamin C, β-carotene, GSH, CAT, and FRAP were decreased, whereas the concentration of TBARS decreased in the first year but increased in the following year, which may be partly explained by the imbalance between antioxidants and pro-oxidants.

Concepts: Antioxidant, Obesity, Oxidative stress, Glutathione, Vitamin C, Bariatric surgery, Gastric bypass surgery, Bariatrics

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Rivaroxaban is a direct factor Xa inhibitor, which is rapidly absorbed in the upper gastrointestinal (GI) tract. In large trials, it has been shown to be effective and safe in VTE treatment. However, in these trials patients with morbid obesity were not reported and it is unknown if the standard dosage of 20 mg rivaroxaban is sufficient for bariatric patients, especially after bariatric surgery, which may impact the resorption of rivaroxaban. We report the case of a bariatric patient with high venous thromboembolism risk and instable INR after recent bariatric surgery, who was switched from Vitamin-K antagonists to rivaroxaban. After intake of 20 mg rivaroxaban, plasma concentration were repeatedly measured until 3 h after the second dose using a commercially available chromogenic aXa-assay. Furthermore, INR and aPTT were measured. Peak concentrations of 224.22 ng/ml were observed. After 6 h, plasma concentration decreased to 86.9 ng/ml and remained stable until 12 h (86.32 ng/ml). After 24 h, a trough level of 35.54 ng/ml was observed. The patients INR did immediately increase and remained significantly elevated throughout the day with a slow decrease. Since peak values of rivaroxaban plasma concentrations were in the expected range of published data, we conclude that resorption of rivaroxaban was immediate and not significantly impaired by bariatric surgery of the upper GI tract. Consequently, no dose adjustments seem to be necessary in this high-risk population.

Concepts: Obesity, Overweight, Warfarin, Weight loss, Bariatric surgery, Digestion, Gastric bypass surgery, Bariatrics