Mechanisms of Weight Loss After Sleeve Gastrectomy and Adjustable Gastric Banding: Far More Than Just Restriction

Diabetes Is Associated with Worse Postoperative Mortality and Morbidity in Bariatric Surgery, Regardless of the Procedure

Background/Objectives: Bariatric surgery is a central cornerstone in obesity treatment. We aimed to assess the impact of diabetes on the postoperative outcomes of bariatric surgery and compare three techniques: sleeve gastrectomy, Roux-en-Y, and gastric banding. Methods: We extracted data from the National Inpatient Sample (2015-2019) using ICD codes. The primary outcome was postoperative mortality. Secondary outcomes were major bleeding, atrial fibrillation, and acute renal failure. Results: Among patients who underwent sleeve gastrectomy, diabetes was associated with a higher adjusted risk of mortality (aOR 2.07 [1.36-3.16]), atrial fibrillation, and acute renal failure, but a similar risk of bleeding. Among patients who underwent Roux-en-Y, diabetes did not increase mortality and bleeding risk. Still, it was associated with a higher risk of atrial fibrillation and acute renal failure. Among patients who underwent gastric banding, diabetes was only associated with a higher risk of bleeding. When comparing the three techniques in diabetes patients, Roux-en-Y was significantly associated with higher mortality and acute renal failure risk when compared to the other procedures. Bleeding was more common in Roux-en-Y than in Sleeve. Conclusions: In total, diabetes is associated with worse postoperative outcomes in bariatric surgery, regardless of the technique. Among diabetes patients, Roux-en-Y was associated with the highest mortality and morbidity.

Gut microbiota and therapy for obesity and type 2 diabetes

There has been a major increase in Type 2 diabetes and obesity in many countries, and this will lead to a global public health crisis, which not only impacts on the quality of life of individuals well but also places a substantial burden on healthcare systems and economies. Obesity is linked to not only to type 2 diabetes but also cardiovascular diseases, musculoskeletal disorders, and certain cancers, also resulting in increased medical costs and diminished quality of life. A number of studies have linked changes in gut in obesity development. Dysbiosis, a deleterious change in gut microbiota composition, leads to altered intestinal permeability, associated with obesity and Type 2 diabetes. Many factors affect the homeostasis of gut microbiota, including diet, genetics, circadian rhythms, medication, probiotics, and antibiotics. In addition, bariatric surgery induces changes in gut microbiota that contributes to the metabolic benefits observed post-surgery. Current obesity management strategies encompass dietary interventions, exercise, pharmacotherapy, and bariatric surgery, with emerging treatments including microbiota-altering approaches showing promising efficacy. While pharmacotherapy has demonstrated significant advancements in recent years, bariatric surgery remains one of the most effective treatments for sustainable weight loss. However, access to this is generally limited to those living with severe obesity. This underscores the need for non-surgical interventions, particularly for adolescents and mildly obese patients. In this comprehensive review, we assess longitudinal alterations in gut microbiota composition and functionality resulting from the two currently most effective anti-obesity treatments: pharmacotherapy and bariatric surgery. Additionally, we highlight the functions of gut microbiota, focusing on specific bacteria, their metabolites, and strategies for modulating gut microbiota to prevent and treat obesity. This review aims to provide insights into the evolving landscape of obesity management and the potential of microbiota-based approaches in addressing this pressing global health challenge.

Risk of Malnutrition in Adults Who Have Undergone Sleeve Gastrectomy: A Retrospective Study

Sleeve gastrectomy achieves long-term weight control by reducing gastric volume. However, postoperative gastrointestinal symptoms and insufficient nutritional intake are likely to occur, which are not conducive to physical health. A retrospective study aimed to investigate changes in nutritional status and associated factors in patients after sleeve gastrectomy. Data were collected from the medical records of patients who underwent sleeve gastrectomy at a teaching hospital in Taiwan. Data from 120 patients who met the eligibility criteria were included in the analysis. The results show that sleeve gastrectomy has a strong weight loss effect. Within 12 months, the average body mass index of the patients decreased by 13.47 kg/m2. The number of morbidly obese patients decreased from 62 (51.7%) to 3 (2.5%). However, surgery is also associated with gastrointestinal symptoms and the threat of malnutrition. The number of patients with moderate to severe nutritional risk increased from 4 (3.3%) before surgery to 24 (20%) at 12-month follow-up. Likewise, the number of patients with anemia increased from 11 (9.2%) to 29 (24.17%). Gender, constipation, and diarrhea affected postoperative nutritional status. These findings suggest that patients after sleeve gastrectomy are at risk of malnutrition and require regular monitoring. Special attention should be given to women and patients with constipation or diarrhea, as they are at a particularly high risk of malnutrition.

The Effect of Laparoscopic Sleeve Gastrectomy on the Course of Non-Alcoholic Fatty Liver Disease in Morbidly Obese Patients during One Year of Follow Up

BACKGROUND

Morbid obesity co-exists with non-alcoholic fatty liver disease in up to 90% of cases. Laparoscopic sleeve gastrectomy leads to a reduction in body mass and thus may improve the course of non-alcoholic fatty liver disease. The aim of this study was to evaluate the effect of laparoscopic sleeve gastrectomy on the resolution of non-alcoholic fatty liver disease.

METHODS

The study included 55 patients with non-alcoholic fatty liver disease who underwent laparoscopic sleeve gastrectomy at a tertiary institution. The analysis consisted of preoperative liver biopsy, abdominal ultrasound, weight loss parameters, Non-Alcoholic Fatty Liver Fibrosis Score and selected laboratory parameters.

RESULTS

Before the surgery, 6 patients were diagnosed with grade 1 liver steatosis, 33 patients with grade 2 and 16 patients with grade 3. One year after the surgery, only 21 patients had features of liver steatosis at ultrasound. All weight loss parameters showed statistically significant changes during the observation; the median percentage of total weight loss was 31.0% (IQR: 27.5; 34.5) with p = 0.0003, the median percentage of excess weight loss was 61.8% (IQR: 52.4; 72.3) with p = 0.0013 and the median percentage of excess body mass index loss was 71.0% (IQR: 61.3; 86.9) with p = 0.0036 12 months after laparoscopic sleeve gastrectomy. The median Non-Alcoholic Fatty Liver Fibrosis Score at baseline was 0.2 (IQR: -0.8; 1.0) and decreased to -1.6 (IQR: -2.4; -0.4) (p < 0.0001). Moderate negative correlations between Non-Alcoholic Fatty Liver Fibrosis Score and percentage of total weight loss (r = -0.434, p < 0.0001), percentage of excess weight loss (r = -0.456, p < 0.0001) and percentage of excess body mass index loss (r = -0.512, p < 0.0001) were found.

CONCLUSIONS

The study supports the thesis that laparoscopic sleeve gastrectomy is an effective method for treatment of non-alcoholic fatty liver disease in patients with morbid obesity.

Incidence of Kidney Stones After Metabolic and Bariatric Surgery-Data from the Scandinavian Obesity Surgery Registry

PURPOSE

Obesity is associated with increased incidence of kidney stones, a risk further increased by metabolic and bariatric surgery, particularly after procedures with a malabsorptive component. However, there is a paucity in reports on baseline risk factor and on larger population-based cohorts. The objective was to evaluate incidence and risk factors for kidney stones after bariatric surgery by comparing them to an age-, sex-, and geographically matched cohort from the normal population.

MATERIAL AND METHODS

Patients operated with primary Roux-en-Y gastric bypass (RYGB), sleeve gastrectomy (SG), or biliopancreatic diversion with duodenal switch (BPD-DS) from 2007 until 2017 within the Scandinavian Obesity Surgery registry were matched 1:10 to controls from the normal population. Hospital admission or outpatient visits due to kidney stones registered in the National Patient Registry were considered as endpoint.

RESULTS

The study included 58,366 surgical patients (mean age 41.0±11.1, BMI 42.0±5.68, 76% women) with median follow-up time 5.0 [IQR 2.9-7.0] years and 583,660 controls. All surgical procedures were associated with a significantly increased risk for kidney stones (RYGB, HR 6.16, [95% CI 5.37-7.06]; SG, HR 6.33, [95% CI 3.57-11.25]; BPD/DS, HR 10.16, [95% CI 2.94-35.09]). Higher age, type 2 diabetes hypertension at baseline, and a preoperative history of kidney stones were risk factors for having a postoperative diagnosis of kidney stones.

CONCLUSION

Primary RYGB, SG, and BPD/DS were all associated with a more than sixfold increased risk for postoperative kidney stones. The risk increased with advancing age, two common obesity-related conditions, and among patients with preoperative history of kidney stones.

Bariatric Surgery as Treatment Strategy of Obesity in Saudi People: Effects of Gut Microbiota

Obesity prevalence is rising globally, as are the number of chronic disorders connected with obesity, such as diabetes, non-alcoholic fatty liver disease, dyslipidemia, and hypertension. Bariatric surgery is also becoming more common, and it remains the most effective and long-term treatment for obesity. This study will assess the influence of Laparoscopic Sleeve Gastrectomy (LSG) on gut microbiota in people with obesity before and after surgery. The findings shed new light on the changes in gut microbiota in Saudi people with obesity following LSG. In conclusion, LSG may improve the metabolic profile, resulting in decreased fat mass and increased lean mass, as well as improving the microbial composition balance in the gastrointestinal tract, but this is still not equivalent to normal weight microbiology. A range of factors, including patient characteristics, geographic dispersion, type of operation, technique, and nutritional and caloric restriction, could explain differences in abundance between studies. This information could point to a novel and, most likely, tailored strategy in obesity therapy, which could eventually be incorporated into health evaluations and monitoring in preventive health care or clinical medicine.

Body composition changes at 12 months following different surgical weight loss interventions in adults with obesity: A systematic review and meta-analysis of randomized control trials

To determine relative lean mass and fat mass changes in adults with obesity following surgical weight loss interventions, a systematic review and meta-analysis was conducted. The Cochrane Central Register of Controlled Trials, PubMed, Web of Science, EMBASE, and Scopus were screened for eligible studies. Inclusion criteria included randomized controlled trials (RCTs) performed in populations with obesity (body mass index ≥30 kg/m² ) aged over 18 years, who underwent any type of bariatric surgery and reported body composition measures via dual-energy X-ray absorptiometry or bio-electrical impedance analysis. Authors conducted full text screening and determined that there were six RCTs eligible for inclusion, with data extracted at 12 months post-surgery. Meta-analysis revealed that, relative to gastric banding, Roux-en-Y gastric bypass (RYGB) led to greater total body mass loss (mean difference [MD]: -9.33 kg [95% CI: -12.10, -6.56]) and greater fat mass loss (MD: -8.86 kg [95% CI: -11.80, -5.93], but similar lean mass loss (MD: -0.55 kg [95% CI: -3.82, 2.71]. RYGB also led to similar changes in total body mass, fat mass, and lean mass compared with sleeve gastrectomy. RYGB results in greater 12-month weight and fat loss, but similar changes in lean mass, compared with gastric banding. Further RCTs comparing body composition changes following different bariatric surgery procedures are required.

Efficacy and Mechanisms of Gastric Volume-Restriction Bariatric Devices

Obesity is a chronic disease that affects over 795 million people worldwide. Bariatric surgery is an effective therapy to combat the epidemic of clinically severe obesity, but it is only performed in a very small proportion of patients because of the limited surgical indications, the irreversibility of the procedure, and the potential postoperative complications. As an alternative to bariatric surgery, numerous medical devices have been developed for the treatment of morbid obesity and obesity-related disorders. Most devices target restriction of the stomach, but the mechanism of action is likely more than just mechanical restriction. The objective of this review is to integrate the underlying mechanisms of gastric restrictive bariatric devices in obesity and comorbidities. We call attention to the need for future studies on potential mechanisms to shed light on how current gastric volume-restriction bariatric devices function and how future devices and treatments can be further improved to combat the epidemic of obesity.

The effect of sleeve ablation of gastric mucosa on body weight and glucose homeostasis in Sprague-Dawley rat model

BACKGROUND

The gastric mucosa is an important endocrine organ, most of which is resected in sleeve gastrectomy (SG). The effect of removing most of the gastric mucosa has not been studied.

OBJECTIVE

To assess the effect of ablating the gastric mucosa (an area proportional to that in SG), on obesity and diabetes in a rat model.

SETTING

The Affiliated Hospital of Xuzhou Medical University in Xuzhou Jiangsu, P. R. China.

METHODS

Among 34 fatty Sprague-Dawley rats, 26 randomly received low-dose streptozotocin (STZ) to induce diabetes and then were randomly assigned to gastric mucosa ablation (GMA, n = 10), sleeve gastrectomy (SG, n = 8), and sham (n = 8) groups. The remaining normal fatty rats were assigned to the non-diabetic gastric mucosa ablation (nGMA, n = 8) group. In the GMA groups, the gastric mucosa was thermally ablated using electrocautery. Rats were followed for 8 weeks postoperatively. Preoperative oral glucose tolerance test (OGTT), insulin tolerance test (ITT), and mixed meal tolerance test (MMTT) were repeated at designated time points postoperatively. Changes in body weight, food intake, and fasting blood glucose were also recorded.

RESULTS

Fasting ghrelin concentration and area under curve (AUC) decreased significantly (P < .05) in the GMA groups and the SG group after surgery. Gastrin concentration remained unchanged in SG but decreased significantly in the GMA groups after surgery. Significantly increased GLP-1 AUC was found in the GMA groups and the SG group postoperatively. The decrease in fasting blood glucose did not differ significantly between the diabetic GMA and SG groups after surgery. Glucose AUC during OGTT in both SG and diabetic GMA groups was decreased significantly from the preoperative level, but the decreased glucose AUC in the SG group was significantly greater (P < .05). The decrease in body weight and food intake in the SG group was significantly greater than in the GMA groups.

CONCLUSION

Ablation of most of the gastric mucosa along the greater curvature is effective in weight loss and glycemic control in a rodent model.

Sleeve gastrectomy ameliorated high-fat diet (HFD)-induced non-alcoholic fatty liver disease and upregulated the nicotinamide adenine dinucleotide +/ Sirtuin-1 pathway in mice

BACKGROUND

/Objective: Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease, and effective treatments are lacking. Bariatric surgery, including sleeve gastrectomy (SG), is a potential therapeutic strategy for NAFLD, but the molecular mechanisms underlying its effects are not fully understood. In this study, the effects of SG and the underlying mechanisms were evaluated in a mouse model of high-fat diet (HFD)-induced NAFLD.

METHODS

C57BL/6 mice were randomly divided into three groups: normal diet with sham operation (NC-Sham group), HFD with sham operation (HFD-Sham group), and HFD with sleeve gastrectomy (HFD-SG group). Glucose metabolism and fat accumulation in the body and liver were analyzed before and after SG. Lipid metabolism and inflammation in the liver were evaluated. Nicotinamide adenine dinucleotide (NAD+) levels as well as nicotinamide riboside kinase (NRK1) and Sirtuin-1 (SIRT1) expression levels were evaluated.

RESULTS

SG attenuated the HFD-induced increases in glucose and insulin levels, fat accumulation, and lipid droplet accumulation. Fatty acid biosynthesis, the expression of the metabolism-related genes ACC1, FASN, SCD1, and DGAT1, and the levels of inflammatory factors were higher in HFD mice than in NC mice and decreased after SG. NAD + concentrations were 54.9 ± 13.4 μmol/mg in NC-Sham mice, 37.6 ± 8.1 μmol/mg in HFD-Sham mice, and 79.9 ± 13.0 μmol/mg in HFD-SG mice (p < 0.05). NRK1 and SIRT1 expression increased dramatically after SG at both the RNA and protein levels.

CONCLUSION

SG significantly alleviated NAFLD in HFD-induced obese mice with increasing the hepatic NAD + levels and upregulating the NRK1/NAD+/SIRT1 pathway.

Treatment of Obesity in Mitigating Metabolic Risk

Through diverse mechanisms, obesity contributes to worsened cardiometabolic health and increases rates of cardiovascular events. Effective treatment of obesity is necessary to reduce the associated burdens of diabetes mellitus, cardiovascular disease, and death. Despite increasing cardiovascular outcome data on obesity interventions, only a small fraction of the population with obesity are optimally treated. This is a primary impetus for this article in which we describe the typical weight loss, as well as the associated impact on both traditional and novel cardiovascular disease risk factors, provided by the 4 primary modalities for obtaining weight loss in obesity-dietary modification, increasing physical activity, pharmacotherapy, and surgery. We also attempt to highlight instances where changes in metabolic risk are relatively specific to particular interventions and appear at least somewhat independent of weight loss. Finally, we suggest important areas for further research to reduce and prevent adverse cardiovascular consequences due to obesity.

Biobehavioural approaches to prevention and treatment: A call for implementation science in obesity research

Much progress has been made in the last 30 years in understanding the causes and mechanisms that contribute to obesity, yet widely available and successful strategies for prevention and treatment remain elusive at population levels. This paper discusses the biobehavioural framework and provides suggestions for applying it to enable greater progress in the science of obesity prevention and treatment, including an increased focus on implementation of science strategies. The objective is to promote a re-evaluation of current views about preventing and treating obesity within a unified biobehavioural framework. Further integration of research exploring how both behavioural and biological components interact is a critical step forward.