Metabolic profiles, energy expenditures, and body compositions of the weight regain versus sustained weight loss patients who underwent Roux-en-Y gastric bypass

Bariatric Metabolic Surgery vs Glucagon-Like Peptide-1 Receptor Agonists and Mortality

Importance

Evidence regarding the relative effectiveness of bariatric metabolic surgery (BMS) and glucagon-like peptide-1 receptor agonists (GLP-1RAs) in reducing mortality and major adverse cardiovascular events (MACEs) is limited.

Objective

To compare all-cause mortality and nonfatal MACEs associated with BMS vs GLP-1RAs for adults with obesity and diabetes and without known cardiovascular disease.

Design, Setting, and Participants

This observational, retrospective cohort study was based on data obtained from the electronic medical records of Clalit Health Services (Clalit), the largest health care organization in Israel. The study included 6070 members aged 24 years or older, who had diabetes and obesity and no prior history of ischemic heart disease, ischemic stroke, or congestive heart failure. Patients who underwent BMS and patients who received GLP-1RAs from January 1, 2008, through December 31, 2021, were matched 1:1 by age, sex, and clinical characteristics. Follow-up ended December 31, 2022.

Exposures

Initiation of BMS or GLP-1RAs.

Main Outcomes and Measures

The primary outcome was all-cause mortality, assessed by multivariate Cox proportional hazards regression models. The secondary outcome was nonfatal MACEs, assessed by multivariate competing risk models.

Results

The study included 3035 matched pairs of patients (total, 6070; mean [SD] age, 51.0 [9.5] years; 3938 women [64.9%]), who were followed up for a median of 6.8 years (IQR, 4.1-9.4 years). Among those with a diabetes duration of 10 years or less (2371 pairs), mortality was lower for those who underwent BMS than for those treated with GLP-1RAs (hazard ratio [HR], 0.38; 95% CI, 0.25-0.58). This association became nonsignificant when weight loss during the follow-up period was also included in the model (HR, 0.79; 95% CI, 0.43-1.48). Among patients with a duration of diabetes longer than 10 years (664 pairs), no survival advantage was demonstrated for BMS over GLP-1RA (HR, 0.65; 95% CI, 0.39-1.08). The risk for nonfatal MACEs did not differ between the treatment groups (HR, 0.74; 95% CI, 0.49-1.10 among patients with a diabetes duration of ≤10 years; HR, 1.21; 95% CI, 0.80-1.85 among patients with a diabetes duration of >10 years).

Conclusions and Relevance

In this cohort study, BMS was associated with greater reduced mortality compared with first-generation GLP-1RAs among individuals with a diabetes duration of 10 years or less, mediated via greater weight loss. No differences in the risk for mortality were observed between the treatment modalities among individuals with a longer duration of diabetes, nor in the occurrence of nonfatal MACEs among all patients.

Post metabolic bariatric surgery weight regain: the importance of GLP-1 levels

Weight regain and insufficient weight loss are essential problems after metabolic bariatric surgery (MBS) in people living with obesity. Changes in the level of glucagon-like peptide-1 (GLP-1) secreted from the gut after bariatric surgery are one of the underlying mechanisms for successful initial weight loss. Studies and meta-analyses have revealed that postprandial GLP-1 levels increase after the Roux-en-Y gastric bypass and sleeve gastrectomy, but fasting GLP-1 levels do not increase significantly. Some observational studies have shown the relationship between higher postprandial GLP-1 levels and successful weight loss after bariatric surgery. There is growing evidence that GLP-1-receptor agonist (GLP-1-RA) use in patients who regained weight after bariatric surgery has resulted in significant weight loss. In this review, we aimed to summarize the changes in endogenous GLP-1 levels and their association with weight loss after MBS, describe the effects of GLP-1-RA use on weight loss after MBS, and emphasize metabolic adaptations in light of the recent literature. We hypothesized that maintaining higher basal-bolus GLP-1-RA levels may be a promising treatment choice in people with obesity who failed to lose weight after bariatric surgery.

Exercise for counteracting weight recurrence after bariatric surgery: a systematic review and meta-analysis of randomized controlled trials

Exercise is recommended to prevent post-surgical weight recurrence. Yet, whether exercise interventions are efficacious in this regard has not been systematically evaluated. Moreover, clinicians lack evidence-based information to advise patients on appropriate exercise frequency, intensity, time, and type (FITT) for preventing weight recurrence. Thus, we conducted a meta-analysis of randomized controlled trials (RCTs) involving exercise interventions specifying FITT and weight measurement ≥12 months post-surgery. We reviewed scientific databases up through February 2022 for RCTs comparing exercise interventions reporting FITT and a nonexercise control group on weight ≥12 months post-surgery. Procedures following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses were registered at the international prospective register of systematic reviews (PROSPERO: CRD42022342337). Of 1368 studies reviewed, 5 met inclusion criteria (n = 189; 47.8 ± 4.2 yr, 36.1 6 ± 3.8 kg·m2, 83.2 ± 9.5% female; 61.7% underwent Roux-en-Y gastric bypass). Exercise interventions were largely supervised, lasted 12-26 weeks, and prescribed 80-210 minutes/week of moderate-to-vigorous intensity combined aerobic and resistance exercise over ≤5 days. Within-group effects showed non-statistically significant weight loss for exercise (d = - .15, 95% confidence interval [CI]: -1.96, 1.65; -1.4 kg; P = .87) and weight gain for control (d = .11, 95% CI: -1.70,1.92; +1.0 kg; P = .90), with no difference between these groups (d = -2.26, 95% CI: -2.07, 1.55; -2.4 kg; P = .78). Exercise elicited an additional 2.4 kg weight loss versus control, although this effect was small and statistically non-significant. Ability to draw definitive conclusions regarding efficacy of exercise interventions for counteracting post-surgical weight recurrence was limited by the small number of trials and methodological issues. Findings highlight the need for more rigorous RCTs of exercise interventions specifically designed to reduce post-surgical weight recurrence.

Changes in Lean Tissue Mass, Fat Mass, Biological Parameters and Resting Energy Expenditure over 24 Months Following Sleeve Gastrectomy

Sleeve gastrectomy (SG) induces weight loss but its effects on body composition (BC) are less well known. The aims of this longitudinal study were to analyse the BC changes from the acute phase up to weight stabilization following SG. Variations in the biological parameters related to glucose, lipids, inflammation, and resting energy expenditure (REE) were concomitantly analysed. Fat mass (FM), lean tissue mass (LTM), and visceral adipose tissue (VAT) were determined by dual-energy X-ray absorptiometry in 83 obese patients (75.9% women) before SG and 1, 12 and 24 months later. After 1 month, LTM and FM losses were comparable, whereas at 12 months the loss of FM exceeded that of LTM. Over this period, VAT also decreased significantly, biological parameters became normalized, and REE was reduced. For most of the BC, biological and metabolic parameters, no substantial variation was demonstrated beyond 12 months. In summary, SG induced a modification in BC changes during the first 12 months following SG. Although the significant LTM loss was not associated with an increase in sarcopenia prevalence, the preservation of LTM might have limited the reduction in REE, which is a longer-term weight-regain criterion.

Thermogenic T cells: a cell therapy for obesity?

Obesity is a widespread public health problem with profound medical consequences and its burden is increasing worldwide. Obesity causes significant morbidity and mortality and is associated with conditions including cardiovascular disease and diabetes mellitus. Conventional treatment options are insufficient, or in the case of bariatric surgery, quite invasive. The etiology of obesity is complex, but at its core is often a caloric imbalance with an inability to burn off enough calories to exceed caloric intake, resulting in storage. Interventions such as dieting often lead to decreased resting energy expenditure (REE), with a rebound in weight ("yo-yo effect" or weight cycling). Strategies that increase REE are attractive treatment options. Brown fat tissue engages in nonshivering thermogenesis whereby mitochondrial respiration is uncoupled from ATP production, increasing REE. Medications that replicate brown fat metabolism by mitochondrial uncoupling (e.g., 2,4-dinitrophenol) effectively promote weight loss but are limited by toxicity to a narrow therapeutic range. This review explores the possibility of a new therapeutic approach to engineer autologous T cells into acquiring a thermogenic phenotype like brown fat. Engineered autologous T cells have been used successfully for years in the treatment of cancers (chimeric antigen receptor T cells), and the principle of engineering T cells ex vivo and transferring them back to the patient is established. Engineering T cells to acquire a brown fat-like metabolism could increase REE without the risks of pharmacological mitochondrial uncoupling. These thermogenic T cells may increase basal metabolic rate and are therefore a potentially novel therapeutic strategy for obesity.

Appetite Changes in Weight Regain and Weight Maintenance After Roux-en-Y Gastric Bypass

PURPOSE

Roux-en-Y gastric bypass (RYGB) surgery produces significant weight loss. However, a number of patients experience weight regain years after surgery. Factors driving weight regain after surgical interventions are currently being explored. Our objective was to investigate appetite-related measures associated with weight regain after RYGB surgery.

MATERIALS AND METHODS

Using a cross-sectional design, 29 participants (49.6 ± 9.1 years of age; current BMI 32.4 ± 4.7 kg/m², 43.6 ± 8.9 months post-RYGB) were stratified into tertiles according to weight regain per month after nadir (weight maintenance (WM), n = 9; low weight regain (LWR), n = 10; and high weight regain (HWR), n = 10). The average weight regain was, by design, significantly different between the groups (WM = 2.2 ± 2.5 kg; LWR = 10.0 ± 3.4 kg; HWR = 14.9 ± 6.3 kg regained, p < 0.05). Appetite (visual analog scales), olfactory performance ("sniffin sticks"), eating behaviors (Three Factor Eating Questionnaire), food reward (Leeds Food Preference Questionnaire), and appetite-related hormones (ghrelin, PYY, GLP-1 and leptin) were measured fasting and in response to a standardized test meal.

RESULTS

Dietary restraint was significantly higher than clinical cutoffs in WM and LWR (p < 0.05). As expected, significant time effects were noted for ghrelin, PYY, and GLP-1, but there were no group differences.

CONCLUSION

The results suggest that appetite-related outcomes are similar across individuals who have maintained weight loss and experienced regain following RYGB.