| 1. |
- Bueter, Marco, et al.
(author)
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Gastric bypass increases energy expenditure in rats.
- 2010
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In: Gastroenterology. - : Elsevier BV. - 1528-0012 .- 0016-5085. ; 138:5, s. 1845-53
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Journal article (peer-reviewed)abstract
- BACKGROUND & AIMS: Mechanisms underlying weight loss maintenance after gastric bypass are poorly understood. Our aim was to examine the effects of gastric bypass on energy expenditure in rats. METHODS: Thirty diet-induced obese male Wistar rats underwent either gastric bypass (n = 14), sham-operation ad libitum fed (n = 8), or sham-operation body weight-matched (n = 8). Energy expenditure was measured in an open circuit calorimetry system. RESULTS: Twenty-four-hour energy expenditure was increased after gastric bypass (4.50 +/- 0.04 kcal/kg/h) compared with sham-operated, ad libitum fed (4.29 +/- 0.08 kcal/kg/h) and sham-operated, body weight-matched controls (3.98 +/- 0.10 kcal/kg/h, P < .001). Gastric bypass rats showed higher energy expenditure during the light phase than sham-operated control groups (sham-operated, ad libitum fed: 3.63 +/- 0.04 kcal/kg/h vs sham-operated, body weight-matched: 3.42 +/- 0.05 kcal/kg/h vs bypass: 4.12 +/- 0.03 kcal/kg/h, P < .001). Diet-induced thermogenesis was elevated after gastric bypass compared with sham-operated, body weight-matched controls 3 hours after a test meal (0.41% +/- 1.9% vs 10.5% +/- 2.0%, respectively, P < .05). The small bowel of gastric bypass rats was 72.1% heavier because of hypertrophy compared with sham-operated, ad libitum fed rats (P < .0001). CONCLUSIONS: Gastric bypass in rats prevented the decrease in energy expenditure after weight loss. Diet-induced thermogenesis was higher after gastric bypass compared with body weight-matched controls. Raised energy expenditure may be a mechanism explaining the physiologic basis of weight loss after gastric bypass.
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| 2. |
- Bueter, Marco, et al.
(author)
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Vagal sparing surgical technique but not stoma size affects body weight loss in rodent model of gastric bypass.
- 2010
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In: Obesity surgery. - : Springer Science and Business Media LLC. - 1708-0428 .- 0960-8923. ; 20:5, s. 616-22
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Journal article (peer-reviewed)abstract
- BACKGROUND: The aim of this study was to evaluate whether gastric bypass with or without vagal preservation resulted in a different outcome. METHODS: Body weight, food intake and postprandial peptide YY (PYY) and glucagon-like peptide (GLP-1) levels were compared between gastric bypass (n = 55) and sham-operated rats (n = 27) in three groups. In group 1 (n = 17), the vagal nerve was not preserved, while in group 2 the vagal nerve was preserved during gastric bypass (n = 10). In group 3, gastric bypass rats (n = 28) were randomised for either one of the two techniques. RESULTS: Rats in which the vagal nerve was preserved during gastric bypass showed a lower body weight (p < 0.001) and reduced food intake (p < 0.001) compared to rats in which the vagal nerve was not preserved during the gastric bypass operation. Levels of PYY and GLP-1 were significantly increased after gastric bypass compared to sham-operated controls (p < 0.05), but there was no difference between gastric bypass rats with and without vagal preservation. Differences in food intake and body weight were not related to the size of the gastro-jejunostomy in gastric bypass rats. There were no signs of malabsorption or inflammation after gastric bypass. CONCLUSION: We propose that the vagal nerve should be preserved during the gastric bypass operation as this might play an important role for the mechanisms that induce weight loss and reduce food intake in rats. In contrast, the gastro-jejunal stoma size was found to be of minor relevance.
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| 3. |
- Buhmann, H., et al.
(author)
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The gut-brain axis in obesity
- 2014
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In: Best Practice & Research in Clinical Gastroenterology. - : Elsevier BV. - 1521-6918. ; 28:4, s. 559-571
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Journal article (peer-reviewed)abstract
- Currently the only effective treatment for morbid obesity with a proven mortality benefit is surgical intervention. The underlying mechanisms of these surgical techniques are unclear, but alterations in circulating gut hormone levels have been demonstrated to be at least one contributing factor. Gut hormones seem to communicate information from the gastrointestinal tract to the regulatory appetite centres within the central nervous system (CNS) via the so-called 'Gut-Brain-Axis'. Such information may be transferred to the CNS either via vagal or non-vagal afferent nerve signalling or directly via blood circulation. Complex neural networks, distributed throughout the forebrain and brainstem, are in control of feeding and energy homoeostasis. This article aims to review how appetite is potentially regulated by these gastrointestinal hormones. Identification of the underlying mechanisms of appetite and weight control may pave the way to develop better surgical techniques and new therapies in the future.
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| 4. |
- Cohen, R., et al.
(author)
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Role of proximal gut exclusion from food on glucose homeostasis in patients with Type 2 diabetes
- 2013
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In: Diabetic Medicine. - : Wiley. - 0742-3071 .- 1464-5491. ; 30, s. 1482-1486
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Journal article (peer-reviewed)abstract
- Aims: To report Type 2 diabetes-related outcomes after the implantation of a duodenal-jejunal bypass liner device and to investigate the role of proximal gut exclusion from food in glucose homeostasis using the model of this device. Methods: Sixteen patients with Type 2 diabetes and BMI <36kg/m2 were evaluated before and 1, 12 and 52weeks after duodenal-jejunal bypass liner implantation and 26weeks after explantation. Mixed-meal tolerance tests were conducted over a period of 120min and glucose, insulin and C-peptide levels were measured. The Matsuda index and the homeostatic model of assessment of insulin resistance were used for the estimation of insulin sensitivity and insulin resistance. The insulin secretion rate was calculated using deconvolution of C-peptide levels. Results: Body weight decreased by 1.3kg after 1week and by 2.4kg after 52weeks (P<0.001). One year after duodenal-jejunal bypass liner implantation, the mean (sem) HbA1c level decreased from 71.3 (2.4) mmol/mol (8.6[0.2]%) to 58.1 (4.4) mmol/mol (7.5 [0.4]%) and mean (sem) fasting glucose levels decreased from 203.3 (13.5) mg/dl to 155.1 (13.1) mg/dl (both P<0.001). Insulin sensitivity improved by >50% as early as 1week after implantation as measured by the Matsuda index and the homeostatic model of assessment of insulin resistance (P<0.001), but there was a trend towards deterioration in all the above-mentioned variables 26weeks after explantation. Fasting insulin levels, insulin area under the curve, fasting C-peptide, C-peptide area under the curve, fasting insulin and total insulin secretion rates did not change during the duodenal-jejunal bypass liner implantation period or after explantation. Conclusions: The duodenal-jejunal bypass liner improves glycaemia in overweight and obese patients with Type 2 diabetes by rapidly improving insulin sensitivity. A reduction in hepatic glucose output is the most likely explanation for this improvement. Diabetic Medicine © 2013 The Authors. Diabetic Medicine © 2013 Diabetes UK.
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| 5. |
- Docherty, N. G., et al.
(author)
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Improvements in the metabolic milieu following Roux-en-Y gastric bypass and the arrest of diabetic kidney disease
- 2014
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In: Experimental Physiology. - : Wiley. - 0958-0670. ; 99:9, s. 1146-1153
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Journal article (peer-reviewed)abstract
- Roux-en-Y gastric bypass (RYGB) is an efficacious intervention for morbid obesity and has a diabetes-remitting effect in patients with obesity and type 2 diabetes mellitus, which occurs prior to significant weight loss. Roux-en-Y gastric bypass is also associated with early and sustained reductions in the risk factor profile for the progression of diabetic complications. Attention is therefore now being placed on RYGB as a metabolic intervention with the capacity to yield therapeutic benefit in relation to the progression of diabetic complications, such as diabetic kidney disease. As alterations in gut anatomy following RYGB coincide with attendant shifts in downstream enteroendocrine signals with direct and indirect resolutionary effects on the kidney, the concept of an endocrine gut-kidney axis post-RYGB is growing. With the model of a gut-kidney axis in mind, this article summarizes emerging data on the effects of RYGB on risk factors for diabetic kidney disease (hyperglycaemia, dyslipidaemia and hypertension), highlighting a potential role for glucagon-like peptide 1 in risk factor reduction.
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| 6. |
- Elias, Erik, 1979, et al.
(author)
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Bone mineral density and expression of vitamin D receptor-dependent calcium uptake mechanisms in the proximal small intestine after bariatric surgery
- 2014
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In: British Journal of Surgery. - : Oxford University Press (OUP). - 0007-1323 .- 1365-2168. ; 101:12, s. 1566-1575
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Journal article (peer-reviewed)abstract
- Background Roux-en-Y gastric bypass may lead to impaired calcium uptake. Therefore, operation-specific effects of gastric bypass and vertical banded gastroplasty on bone mineral density (BMD) were examined in a randomized clinical trial. Bone resorption markers and mechanisms of decreased calcium uptake after gastric bypass were investigated using blood and endoscopic samples from two additional patient cohorts. Methods Total BMD and non-weight-bearing skull BMD were measured by dual-energy X-ray absorptiometry at baseline, and 1 and 6years after gastric bypass or vertical banded gastroplasty in patients who were not receiving calcium supplements. Bone resorption markers in serum and calcium uptake mechanisms in jejunal mucosa biopsies were analysed after gastric bypass by proteomics including radioimmunoassay, gel electrophoresis and mass spectrometry. Results One year after surgery, weight loss was similar after gastric bypass and vertical banded gastroplasty. There was a moderate decrease in skull BMD after gastric bypass, but not after vertical banded gastroplasty (P<0·001). Between 1 and 6years after gastric bypass, skull BMD and total BMD continued to decrease (P=0·001). C-terminal telopeptide levels in serum had increased twofold by 18months after gastric bypass. Proteomic analysis of the jejunal mucosa revealed decreased levels of heat-shock protein 90β, a co-activator of the vitamin D receptor, after gastric bypass. Despite increased vitamin D receptor levels, expression of the vitamin D receptor-regulated calcium transporter protein TRPV6 decreased. Conclusion BMD decreases independently of weight after gastric bypass. Bone loss might be attributed to impaired calcium absorption caused by decreased activation of vitamin D-dependent calcium absorption mechanisms mediated by heat-shock protein 90β and TRPV6.
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| 7. |
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| 8. |
- le Roux, Carel W, et al.
(author)
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The physiology of altered eating behaviour after Roux-en-Y gastric bypass
- 2014
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In: Experimental Physiology. - : Wiley. - 0958-0670. ; 99:9, s. 1128-1132
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Journal article (peer-reviewed)abstract
- Obesity and its related comorbidities can be detrimental for the affected individual, as well as constituting a major challenge to public health systems worldwide. Currently, the most effective treatment option leading to clinically significant and maintained body weight loss and reduction in obesity-related morbidity and mortality is obesity surgery, which is recommended for patients with a body mass index of >40 kg m(-2), or >35 kg m(-2) if obesity-associated comorbidities, such as type 2 diabetes mellitus, are present. This report focuses on the altered eating behaviour after the most common of these operations, the Roux-en-Y gastric bypass. Animal and human experiments designed to understand the underlying physiological mechanisms of altered taste and appetite are discussed.
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| 9. |
- Miras, A D, et al.
(author)
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Application of the International Diabetes Federation and American Diabetes Association criteria in the assessment of metabolic control after bariatric surgery.
- 2014
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In: Diabetes, obesity & metabolism. - : Wiley. - 1463-1326 .- 1462-8902. ; 16:1, s. 86-89
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Journal article (peer-reviewed)abstract
- The International Diabetes Federation (IDF) and the American Diabetes Association (ADA) have introduced specific criteria to define the 'optimization' of the metabolic state and glycaemic 'remission' of type 2 diabetes mellitus (T2DM) after bariatric surgery, respectively. Our objective was to assess the percentage of patients achieving these criteria. Data were collected for body mass index, glycaemic markers, lipids, blood pressure, hypoglycaemia and medication usage from 396 morbidly obese T2DM patients who underwent bariatric surgery in two centres and followed up for 2years. At year 1, 14% of patients achieved the IDF criteria and 38% the ADA criteria, whereas at 2years 8 and 9% satisfied these criteria, respectively. A relatively low proportion of patients achieved optimization of the metabolic state and T2DM remission. These patients may potentially benefit from the combination of bariatric surgery and adjuvant medical therapy to achieve optimal metabolic outcomes.
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| 10. |
- Miras, Alexander D, et al.
(author)
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Metabolic surgery: shifting the focus from glycaemia and weight to end-organ health.
- 2014
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In: The lancet. Diabetes & endocrinology. - 2213-8595. ; 2:2, s. 141-151
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Journal article (peer-reviewed)abstract
- Bariatric surgery is the most effective treatment for weight loss and glycaemic control. The focus of clinical studies and clinical experience has predominantly been on the numerical reductions of bodyweight and glucose after surgery. In this Series paper, we examine evidence on the efficacy of bariatric surgery for pancreatic, renal, retinal, peripheral nervous, cardiovascular, hepatic, and reproductive end-organ damage or disease. The overall conclusions are that, in most cases, patients' end-organ damage is expected to either stabilise or improve postoperatively. However, some of these clinical outcomes have not been assessed with robust methods and, in many cases, do not have support from randomised controlled clinical trials comparing bariatric surgery with non-surgical interventions. Such trials are urgently needed to inform patients and clinicians on whether the risks of surgery outweigh the significant benefits for end-organ health.
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