Glucagon-like peptide-1 receptor agonists, weight loss, and gastric emptying: have I gut news for you

Newer pharmacological interventions directed at gut hormones for obesity

The objective is to review the newer pharmacological interventions for obesity, specifically single, dual and triple incretin receptor agonists that are either available or in the pipeline for treatment of obesity. The three incretin receptor targets are glucagon like peptide-1 (GLP-1), glucose-dependent insulinotropic peptide (GIP) and glucagon. There are several approved single or dual incretin agonists which can be administered subcutaneously daily (e.g., liraglutide) or weekly (e.g., semaglutide, dulaglutide, and exenatide QW), and other experimental dual or triple incretin agonists. Analogues of amylin, peptide YY and oxyntomodulin, as well as the combination of a GLP1R agonist and GIPR antagonist also are in development. Oral semaglutide (administered daily) is approved for type 2 diabetes mellitus and is on track for regulatory review for obesity. The review includes specifically perspectives on the effects of these mechanisms and pharmacological agents on gastric emptying, which contribute to satiation and weight loss, in addition to the established evidence on effects on central mechanisms controlling appetite. In the future, it is anticipated that small molecule GLP-1 receptor agonists (e.g., oral danuglipron) will be developed for treating obesity. These pharmacological agents are having significant impact on glycaemic control and obesity and on their co-morbidities.

Efficacy and Safety of Glucagon-Like Peptide-1 Receptor Agonists on Body Weight and Cardiometabolic Parameters in Individuals With Obesity and Without Diabetes: A Systematic Review and Meta-Analysis

OBJECTIVE

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs), initially for type 2 diabetes mellitus, show promise in promoting weight loss and improving heart health in obese individuals without diabetes. Our goal was to examine existing research for conclusive evidence on various types of GLP-1 RAs for weight loss and cardiometabolic benefits in obesity without diabetes.

METHODS

We conducted an electronic search on PubMed, Scopus, and Cochrane Central using keywords, such as "GLP-1 RA," "obesity," and "weight loss." We considered all available global GLP-1 RAs for inclusion. Our analysis focused on weight loss, blood pressure (BP) changes (systolic and diastolic BPs), and lipid profile effects (high-density lipoprotein, low-density lipoprotein, total cholesterol, and triacylglycerol). We used a random-effects meta-analysis with the standardized mean difference (SMD), mean difference (MD), odds ratio, and relative risk to present the results.

RESULTS

Our search yielded a total of 7535 articles. We included 15 trials in our study. GLP-1 RAs led to significant weight loss (MD, -8.77 kg; P <.01) in obese individuals. GLP-1 RAs also improved the systolic BP (MD, -4.13 mm Hg; P <.01), diastolic BP (MD, -1.39 mm Hg; P <.01), and lipid profiles, including improved levels of triacylglycerol (SMD, -0.99 mg/dL; P <.01), total cholesterol (SMD, -0.73 mg/dL; P <.01), very low-density lipoprotein (SMD, -1.11 mg/dL; P <.01), and low-density lipoprotein (SMD, -0.27 mg/dL; P <.01), and significantly increased high-density lipoprotein levels (SMD, 0.11 mg/dL; P <.01). However, GLP-1 RAs were associated with an increased risk of gastrointestinal adverse events.

CONCLUSION

GLP-1 RAs were found to be beneficial for not only weight loss but also reduction in risk factors for cardiovascular disease such as BP and lipid profile. Consistent beneficial results were observed across the various subtypes of GLP-1 RAs.

The role of gastric function in control of food intake (and body weight) in relation to obesity, as well as pharmacological and surgical interventions

PURPOSE

The objectives of this review are to summarize the role of gastric motor functions in the development of satiation (defined broadly as postprandial fullness) and satiety (reduced appetite or postponing desire to eat after a meal) and their impact on weight change. The specific topics are the methods of measurement of gastric emptying and accommodation and their impact on food intake, satiation, and satiety. A second focus contrasts bariatric surgery to endoscopic gastroplasty that alter gastric emptying and incretin responses in markedly divergent manners.

BACKGROUND

The hormone, GLP-1, retards gastric emptying and increases gastric accommodation through vagally-mediated effects. Indeed, these effects provide the basis for the association of altered gastric emptying in the appetite and weight loss responses to pharmacological interventions particularly by those acting on receptors of incretin agonists such as liraglutide and the dual agonists, tirzepatide and cotadutide, all of which retard gastric emptying. In fact, retardation of gastric emptying and gastrointestinal adverse effects have been shown to contribute in part to the weight loss in response to this class of pharmacological agents.

SUMMARY

The motor functions of the stomach are relevant to postprandial fullness and to interventions aimed at weight loss in people with obesity.

Review article: Pharmacologic management of obesity - updates on approved medications, indications and risks

BACKGROUND

Obesity has reached epidemic proportions, with >40% of the US population affected. Although traditionally managed by lifestyle modification, and less frequently by bariatric therapies, there are significant pharmacological advancements.

AIMS

To conduct a narrative review of the neurohormonal and physiological understanding of weight gain and obesity, and the development, clinical testing, indications, expected clinical outcomes, and associated risks of current FDA-approved and upcoming anti-obesity medications (AOMs).

METHODS

We conducted a comprehensive review in PubMed for articles on pathophysiology and complications of obesity, including terms 'neurohormonal', 'obesity', 'incretin', and 'weight loss'. Next, we searched for clinical trial data of all FDA-approved AOMs, including both the generic and trade names of orlistat, phentermine/topiramate, bupropion/naltrexone, liraglutide, and semaglutide. Additional searches were conducted for tirzepatide and retatrutide - medications expecting regulatory approval. Searches included combinations of terms related to mechanism of action, indications, side effects, risks, and future directions.

RESULTS

We reviewed the pathophysiology of obesity, including specific role of incretins and glucagon. Clinical data supporting the use of various FDA-approved medications for weight loss are presented, including placebo-controlled or, when available, head-to-head trials. Beneficial metabolic effects, including impact on liver disease, adverse effects and risks of medications are discussed, including altered gastrointestinal motility and risk for periprocedural aspiration.

CONCLUSION

AOMs have established efficacy and effectiveness for weight loss even beyond 52 weeks. Further pharmacological options, such as dual and triple incretins, are probable forthcoming additions to clinical practice for combating obesity and its metabolic consequences such as metabolic dysfunction-associated steatotic liver disease.