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Summary: Obesity can decrease the lung function. The proposed mechanisms of reduced lung function in persons with obesity have been altered mechanical properties in the lung and chest wall, airway narrowing and increased respiratory resistance. The aim of this current study was to analyse the long‐term results after gastric bypass surgery in patients with reduced lung function. The bariatric surgery observation study invited patients to a follow up 10 years after gastric bypass surgery. We compared the spirometry results before surgery to the spirometry 10 years after surgery. Thirty percent of 198 participants had reduced lung function before surgery. There was no significant relation between body mass index before surgery and lung function. Seventy‐three percent of the participants with reduced lung function had normal lung function 10 years after surgery. There was no significant relation between the degree of weight loss and the improvement in lung function. Most participants with reduced lung function had normal lung function 10 years after gastric bypass surgery. There was no significant correlation between weight loss and improvement in lung function. [ABSTRACT FROM AUTHOR]

In this study, we investigated how Roux‐en‐Y gastric bypass (RYGB) enhances glucagon‐like peptide 1 (GLP‐1) response in GK rats and explored the potential link between RYGB‐stimulated BAs/FXR signalling and GLP‐1R‐linked signalling in β‐cells, a key pathway that regulates glucose‐stimulated insulin secretion (GSIS). Here we show that RYGB restores GLP‐1R expression in GK rat islets. This involves increased total BAs as well as chenodeoxycholic acid (CDCA), leading to FXR activation, increasing FXR binding to the promoter of Glp‐1r and enhancing occupancy of histone acetyltransferase steroid receptor coactivator‐1 (SRC1), thus increasing histone H3 acetylation at the promoter. These coordinated events bring about increased GLP‐1R expression, resulting in greater GLP‐1 response in β‐cells. Moreover, ablation of FXR suppressed the stimulatory effects of GLP‐1. Thus, this study unravels the crucial role of the BAs/FXR/SRC1 axis‐controlled GLP‐1R expression in β‐cells, which results in enhanced incretin effect and normalized blood glucose of GK rats after RYGB. [ABSTRACT FROM AUTHOR]

Summary: The prevalence of obesity and metabolic diseases such as type 2 diabetes and nonalcoholic fatty liver disease (NAFLD) has risen dramatically over the past decades. At present, bariatric surgery is the most effective treatment for this global health problem, through effects on food intake, gut hormone secretion, metabolic signaling pathways, and adipose tissue dysfunction. The liver occupies a central role in carbohydrate, protein, and lipid metabolism. Notably, a reduction in hepatic fat content and an improvement in hepatic insulin resistance are among the earliest beneficial effects of bariatric surgery, which has therefore emerged as an attractive treatment option for NAFLD. However, as the scope and popularity of weight loss surgery have expanded, new questions have arisen regarding its safety in patients with liver cirrhosis, the outcome of liver transplantation in patients with a history of bariatric surgery, and over incidental reports of liver failure following surgery. Studies in humans and rodents have also linked bariatric surgery to an increased risk of developing alcohol use disorder, a major risk factor for liver disease. This review integrates data from clinical and translational research to delineate both the beneficial impact of bariatric surgery on the liver and the potential risks involved. [ABSTRACT FROM AUTHOR]

Summary: Substantial differences in the response of gut microbial composition to metabolic and bariatric surgery have been reported. Therefore, the goal of the present review is to evaluate if methodological differences could be driving this lack of consistency. A search was conducted using PUBMED, Web of Science, Science Direct and COCHRANE using the following inclusion criteria: human studies written in English with a baseline sampling point, using gut microbiota as an outcome and either Roux‐n‐Y gastric bypass or sleeve gastrectomy. Sixteen articles were selected (total 221 participants). Roux‐n‐Y gastric bypass caused more alterations in gut microbial composition in comparison with sleeve gastrectomy. Substantial variability was found in study designs, data collection and analyses across studies. Increases in several families and genera from the phylum Proteobacteria and Bacteroidetes, the family Streptococcaceae, the species Akkermansia muciniphila and Streptococcus salivarius and a decrease in the phylum Firmicutes and the family Bifidobacteriaceae were reported. There is a need for standardization not only of microbial analysis but also of study designs when analysing the effect of bariatric surgery on the human gut microbiome. In addition, outcomes from different surgical procedures should not be combined as they produce distinctive effects on gut microbial composition. [ABSTRACT FROM AUTHOR]

Summary: Objective: The modern food environment is a key driver of rising levels of obesity. While olfaction is known to play a major role in food choice; however, its relationship to obesity is yet to be understood. This review assesses current knowledge of the interaction between obesity and olfaction. Methods: This review is based on observational studies comparing olfactory abilities across weight groups (N = 10) and clinical studies evaluating olfactory changes following bariatric surgery (N = 9). Meta‐analyses were performed on data collected by a standard olfactory assessment tool (Sniffin΄ Sticks), to test whether olfaction has any association with body weight or bariatric surgery. Results: This review synthesizes findings derived from 38 datasets, with a total of 1432 individual olfactory assessments. The meta‐analyses suggest that olfactory function is negatively correlated with body weight. In addition, Roux‐en‐Y gastric bypass patients frequently report olfactory changes, yet more pronounced and immediate shifts have been observed among sleeve gastrectomy recipients. Conclusions: Our review finds strong evidence for the link between olfaction and obesity and indicates that bariatric surgery (particularly the sleeve gastrectomy) is effective in reversing olfactory decline associated with obesity. In conclusion, we present mechanistic models to underpin the observed relationship between olfaction and obesity. [ABSTRACT FROM AUTHOR]

Abstract: Roux‐en‐Y gastric bypass surgery (RYGB) is one of the most effective treatments for morbid obesity. However, increased substance abuse following RYGB has been observed clinically. This study examined the effects of RYGB on the dopamine system to elucidate these observed changes in reward‐related behavior. Rats were assigned to four groups: normal diet with sham surgery, ad libitum high fat (HF) diet with sham surgery, restricted HF diet with sham surgery, and HF diet with RYGB surgery. Following surgeries, rats were kept on their respective diets for 9 weeks before they were sacrificed. [3H]SCH 23390, [3H]Spiperone, and [3H]WIN35 428 autoradiography was performed to quantify the effects of diet and RYGB surgery on dopamine type 1‐like receptor (D1R)‐like, dopamine type 2‐like receptor (D2R)‐like, and dopamine transporter (DAT) binding. Rats on a chronic HF diet became obese with reduced D1R‐like binding within the ventrolateral striatum and the nucleus accumbens core, reduced D2R‐like binding in all areas of the striatum and nucleus accumbens core and shell, and reduced DAT binding in the dorsomedial striatum. Restricted HF diet rats showed similar reductions in D1R‐like and D2‐R‐like binding as the obese rats, and reduced DAT binding within all areas of the striatum. Both RYGB and restricted HF diet rats showed similar weight reductions, with RYGB rats showing no difference in binding compared to controls. The observed changes in binding between non‐treated obese rats and RYGB rats demonstrates that HF dietary effects on the dopamine system were reversed by RYGB. [ABSTRACT FROM AUTHOR]

Background: Obesity has been shown to trigger adaptive increases in pancreas parenchymal and fat volume. Consecutively, pancreatic steatosis may lead to beta-cell dysfunction. However, it is not known whether the pancreatic tissue components decrease with weight loss and pancreatic steatosis is reversible following Roux-en-Y gastric bypass (RYGB). Therefore, the objective of the study was to investigate the effects of RYGB-induced weight loss on pancreatic volume and glucose homeostasis.Methods: Eleven patients were recruited in the Obesity Centre of the University Medical Centre Hamburg-Eppendorf. Before and 6 months after RYGB, total GLP-1 levels were measured during oral glucose tolerance test. To assess changes in visceral adipose tissue and pancreatic volume, MRI was performed. Measures of glucose homeostasis and insulin indices were assessed. Fractional beta-cell area was estimated by correlation with the C-peptide-to-glucose ratio; beta-cell mass was calculated by the product of beta-cell area and pancreas parenchymal weight.Results: Pancreas volume decreased from 83.8 (75.7-92.0) to 70.5 (58.8-82.3) cm3 (mean [95% CI], P = .001). The decrease in total volume was associated with a significant decrease in fat volume. Fasting insulin and C-peptide were lower post RYGB. HOMA-IR levels decreased, whereas insulin sensitivity increased (P = .03). This was consistent with a reduction in the estimated beta-cell area and mass.Conclusions: Following RYGB, pancreatic volume and steatosis adaptively decreased to "normal" levels with accompanying improvement in glucose homeostasis. Moreover, obesity-driven beta-cell expansion seems to be reversible; however, future studies must define a method to more accurately estimate functional beta-cell mass to increase our understanding of glucose homeostasis after RYGB. [ABSTRACT FROM AUTHOR]

Roux-en-Y gastric bypass (RYGB) is associated with the remission of type 2 diabetes mellitus (DM). There are a number of scoring systems available that help predict type 2 diabetes remission rates after bariatric surgery; however, relatively few have been validated externally. The DiaRem score, comprised of four preoperative variables (age, haemoglobin A1c [HbA1c], sulfonylurea and insulin-sensitizing agent use and insulin use), allows for the identification of patients who are most likely to have DM remission following RYGB. Our primary objective was to determine the variables predictive of DM remission 1 year post-RYGB, determine how well the DiaRem score predicts DM remission 1 year post-RYGB and identify the optimal cut-off DiaRem score. The study is based on results of RYGB performed across multiple centres in Ontario, Canada, overseen by the Centre for Surgical Invention and Innovation in Hamilton, with direction from the Ontario Bariatric Network. Regression analysis was used to determine the predictive value of demographic and clinical variables and that of the DiaRem score. The optimal DiaRem cut-off score was determined using sensitivity and specificity analysis. Of 3874 patients in the Ontario Bariatric Registry between January 2010 and February 2015, 915 had complete 1-year follow-up data. Among these, 15 were not classified as having DM at baseline and were excluded. Of the remaining 900 patients with type 2 diabetes and who underwent RYGB surgery, 333 (37.0%) had DM remission at 1-year follow-up. Three of four DiaRem variables (age, HbA1c, insulin use), in addition to use of any hypoglycaemic agent, were associated with DM remission. DiaRem score had moderate predictive value. A DiaRem score cut-off of <5 had a sensitivity of 71.8% and specificity of 71.3%. This study provides guidance to clinicians in using the DiaRem score to inform the selection and prioritization of patients to ensure timely access to bariatric surgery for those who are likely to benefit the most. [ABSTRACT FROM AUTHOR]

Roux-en- Y gastric bypass ( RYGB) leads to a major weight loss in obese patients. However, given that most patients remain obese after the weight loss, regular exercise should be part of a healthier lifestyle. The primary aim of this study was to investigate the cardiopulmonary fitness in obese patients before and after RYGB. Thirty-four patients had body composition and cardiopulmonary fitness (VO2max) assessed and completed questionnaires regarding physical activity and function twice before RYGB (time points A and B) and 4 and 18 months after surgery (time points C and D). Weight loss was 37 ± 2 kg during the study period. VO2max increased (A: 21 ± 1 vs D: 29 mL/min/kg, P < 0.001), but absolute VO2max decreased (A: 2713 ± 126 vs 2609 ± 187 mL/min, P = 0.02) and VO2max per kilogram fat free mass did not change. Self-perceived limitations to perform exercise decreased and self-perceived physical fitness increased after RYGB. Self-reported low- and high-intensity physical activity did not change. With weight loss, self-rated fitness level increased and the limitations to perform exercise decreased in RYGB patients. Nevertheless, as shown by the lower absolute VO2max, RYGB patients do not adopt new exercise habits following surgery. [ABSTRACT FROM AUTHOR]

Aim High-fat diets are known to contribute to the development of obesity and related co-morbidities including non-alcoholic fatty liver disease ( NAFLD). The accumulation of hepatic lipid may increase endoplasmic reticulum ( ER) stress and contribute to non-alcoholic steatohepatitis and metabolic disease. We hypothesized that bariatric surgery would counter the effects of a high-fat diet ( HFD) on obesity-associated NAFLD. Methods Sixteen of 24 male Sprague Dawley rats were randomized to Sham ( N = 8) or Roux-en-Y gastric bypass ( RYGB) surgery ( N = 8) and compared to Lean controls ( N = 8). Obese rats were maintained on a HFD throughout the study. Insulin resistance ( HOMA- IR), and hepatic steatosis, triglyceride accumulation, ER stress and apoptosis were assessed at 90 days post-surgery. Results Despite eating a HFD for 90 days post-surgery, the RYGB group lost weight (−20.7 ± 6%, P < 0.01) and improved insulin sensitivity ( P < 0.05) compared to Sham. These results occurred with no change in food intake between groups. Hepatic steatosis and ER stress, specifically glucose-regulated protein-78 (Grp78, P < 0.001), X-box binding protein-1 ( XBP-1) and spliced XBP-1 ( P < 0.01), and fibroblast growth factor 21 ( FGF21) gene expression, were normalized in the RYGB group compared to both Sham and Lean controls. Significant TUNEL staining in liver sections from the Obese Sham group, indicative of accelerated cell death, was absent in the RYGB and Lean control groups. Additionally, fasting plasma glucagon like peptide-1 was increased in RYGB compared to Sham ( P < 0.02). Conclusion These data suggest that in obese rats, RYGB surgery protects the liver against HFD-induced fatty liver disease by attenuating ER stress and excess apoptosis. [ABSTRACT FROM AUTHOR]

Aim: Bariatric surgery induces significant weight loss, increases insulin sensitivity, and reduces mortality, but the underlying mechanisms are not clear. It was hypothesized that Roux-en-Y gastric bypass (RYGB) surgery improves metabolic profile along with weight loss. The objective of this pilot study was to evaluate changes in serum metabolites and fatty acids (FA) at 2 weeks and 6 months after RYGB.Materials and Methods: Serum samples were collected pre-surgery, at 2 weeks and 6 months post-surgery from 20 patients undergoing RYGB surgery. Serum non-esterified free FA (NEFA) were measured. Serum metabolites and FA were measured using nuclear magnetic resonance spectroscopy and improved direct fatty acid methyl ester synthesis and the gas chromatography/mass spectrometry method, respectively, in subjects who completed follow-up at 6 months (n = 8).Results: Mean (standard deviation) percent total weight loss was 6.70% (1.7) and 24.91% (6.63) at 2 weeks (n = 15) and 6 months (n = 8) post-surgery, respectively. NEFA were significantly reduced at 6 months post-surgery (P = 0.001, n = 8). Serum branched chain amino acids, 2-aminobutyrate, butyrate, 2-hydroxybutyrate, 3-hydroxybutyrate, acetone, 2-methylglutarate, and 2-oxoisocaproate were significantly reduced, while serum alanine, glycine, pyruvate, and taurine were significantly elevated at 6 months post-surgery compared with pre-surgery (n = 8, P < 0.05). Also, serum FA C10:0, C13:0, C14:0, C15:0, and C18:0 increased significantly (n = 8, P < 0.05) by 6 months post-surgery.Conclusions: Changes in serum metabolites and FA at 6 months post-RYGB surgery in this pilot study with limited number of participants are suggestive of metabolic improvement; larger studies are warranted for confirmation. [ABSTRACT FROM AUTHOR]