Effect of the glucagon-like peptide-1 receptor agonist liraglutide, compared to caloric restriction, on appetite, dietary intake, body fat distribution and cardiometabolic biomarkers: A randomized trial in adults with obesity and prediabetes

Semaglutide as a promising treatment for hypothalamic obesity: a six-month case series on four females with craniopharyngioma

PURPOSE

Patients with hypothalamic pathology often develop hypothalamic obesity, causing severe metabolic alterations resulting in increased morbidity and mortality. Treatments for hypothalamic obesity have not proven very effective, although the glucagon-like peptide-1 receptor agonist semaglutide has been shown to have positive effects. We examined semaglutide's effect on weight loss in a sample of patients with hypothalamic obesity.

METHODS

Four female patients with hypothalamic obesity resulting from treatment of craniopharyngiomas were treated with semaglutide for six months. Whole Body Dual-energy x-ray absorptiometry scans were performed, and blood samples drawn at baseline and after six months. Semaglutide dosages were increased monthly along with tracking of body weight and eating behavior (Three Factor Eating Questionnaire, TFEQ-R18).

RESULTS

BMI was reduced in all cases, with an average of 7.9 BMI (range: 6.7 to 10.1) corresponding to a weight loss of 17.0% (range: 11.3-22.4%) or 20.2 kg (range 16.2 kg to 23.4 kg). We found a comparable reduction in total fat mass (17.2%, p = 0.006) and lean mass (16.0%, p = 0.05), whereas bone mass was unchanged (2.6%, p = 0.12). All cases reported an increase in energy levels, improved mobility and physical activity. Unfavorable eating behaviors were reduced after 1 month of treatment (emotional eating - 41 points, p = 0.02, uncontrolled eating - 23 points, p = 0.11). HbA1c and total cholesterol were significantly reduced (p = 0.014 for both).

CONCLUSION

Semaglutide is a promising and safe treatment option for HO, that improves eating behavior, reduces weight, and improves metabolic markers.

Liraglutide's Effect on Weight Management in Subjects With Pre-diabetes: A Systematic Review & Meta-Analysis

BACKGROUND

Despite the growing literature, the effectiveness of liraglutide in weight management among individuals with prediabetes and in preventing the disease remains controversial. This study aims to critically evaluate the extent of liraglutide's impact on weight management in this population and assess the heterogeneity among extant studies.

METHODS

A systematic literature search was conducted across MEDLINE, Embase, ClinicalTrials.gov, and the reference list of retrieved studies to identify eligible English language randomized controlled trials evaluating liraglutide's effect on weight in individuals with pre-diabetes. Non-randomized studies, studies not reporting relevant outcomes, and those conducted on patients with type 2 diabetes were excluded from this review. Outcomes included a change from baseline in absolute body weight in kg, body mass index (BMI), waist circumference, glycosylated hemoglobin (HbA1c), and low-density lipoprotein cholesterol levels. Additional safety outcomes were also reported. Data were analyzed using R statistical software version 4.3.1. A fixed-effect model was used when pooling crude numbers for study outcomes. Moreover, a sensitivity analysis using random-effect model was performed and heterogeneity was assessed using I2 statistics.

RESULTS

Five eligible studies were included, with a total of 1604 subjects in the liraglutide arm and 859 subjects in the control arm. Participants exposed to liraglutide showed a decrease in body weight (mean difference [MD] = -4.95 kg; 95% CI -5.16, -4.73; I2 = 93%), BMI (MD = -2.06 kg/m2; 95%CI -2.22, -1.89; I2 = 97%), waist circumference (MD = -4.61 cm; 95% CI -4.79, -4.43; I2 = 82%), HbA1c (MD = -0.33%; 95%CI -0.34, -0.31; I2 = 100%), and low-density lipoprotein cholesterol levels (MD = -0.36 mmol/L; 95% CI -0.39, -0.33; I2 = 99%). The overall effect size remained similar when using a random-effects model for all outcomes. In addition, the rate of adverse events was higher with liraglutide when compared to the control; however, the dropout rates were relatively lower in the former arm.

CONCLUSION

While our meta-analysis suggests that liraglutide can reduce body weight, BMI, waist circumference, and HbA1c levels in individuals with pre-diabetes, the findings should be interpreted cautiously due to limitations such as the small number of trials and their short duration, and variability in dosages. Further randomized controlled trials examining long-term outcomes are essential to validate these findings and address the high heterogeneity among the studies included in this analysis.

Glucagon-like peptide-1 receptor agonists in adolescents with overweight or obesity with or without type 2 diabetes multimorbidity-a systematic review and network meta-analysis

AIM

To synthesize the evidence on the effects of glucagon-like peptide-1 receptor agonists (GLP-1RAs) in adolescents with overweight or obesity.

MATERIALS AND METHODS

For this systematic review and network meta-analysis, we searched five databases and registries until 2 March 2024 for eligible randomized controlled trials (RCTs). The primary outcome was weight change. We did a pairwise meta-analysis to compare GLP-1RAs and placebo, followed by a drug-wise network meta-analysis (NMA) to compare GLP-1RAs against each other.

RESULTS

We screened 770 records to include 12 RCTs with 883 participants. The evidence suggests that GLP-1RAs reduced weight (mean difference -4.21 kg, 95% confidence interval [CI] -7.08 to -1.35) and body mass index (BMI; mean difference -2.11 kg/m2, 95% CI -3.60 to -0.62). The evidence on waist circumference, body fat percentage and adverse events (AEs) was very uncertain. The results remained consistent with subgroup analyses for coexisting type 2 diabetes. Longer therapy duration led to a greater reduction in weight and BMI. In the NMA, semaglutide led to the greatest weight reduction, followed by exenatide, liraglutide and lixisenatide.

CONCLUSIONS

The evidence suggests that GLP-1RAs reduce most weight-related outcomes in adolescents, with semaglutide being the most efficacious. There is uncertain evidence on body fat and serious AEs, probably due to fewer studies and low incidence, respectively. Larger RCTs with head-to-head comparisons, pragmatic design, adiposity-related outcomes, and economic evaluation can further guide the use and choice of GLP-1RAs.

Changes in lean body mass with glucagon-like peptide-1-based therapies and mitigation strategies

Weight loss induced by glucagon-like peptide-1 receptor agonists (GLP-1RAs) and dual glucagon-like peptide-1 receptor (GLP-1R)/glucose-dependent insulinotropic polypeptide receptor agonists is coming closer to the magnitudes achieved with surgery. However, with greater weight loss there is concern about potential side effects on muscle quantity (mass), health and function. There is heterogeneity in the reported effects of GLP-1-based therapies on lean mass changes in clinical trials: in some studies, reductions in lean mass range between 40% and 60% as a proportion of total weight lost, while other studies show lean mass reductions of approximately 15% or less of total weight lost. There are several potential reasons underlying this heterogeneity, including population, drug-specific/molecular, and comorbidity effects. Furthermore, changes in lean mass may not always reflect changes in muscle mass as the former measure includes not only muscle but also organs, bone, fluids, and water in fat tissue. Based on contemporary evidence with the addition of magnetic resonance imaging-based studies, skeletal muscle changes with GLP-1RA treatments appear to be adaptive: reductions in muscle volume seem to be commensurate with what is expected given ageing, disease status, and weight loss achieved, and the improvement in insulin sensitivity and muscle fat infiltration likely contributes to an adaptive process with improved muscle quality, lowering the probability for loss in strength and function. Nevertheless, factors such as older age and severity of disease may influence the selection of appropriate candidates for these therapies due to risk of sarcopenia. To further improve muscle health during weight loss, several pharmacological treatments to maintain or improve muscle mass designed in combination with GLP-1-based therapies are under development. Future research on GLP-1-based and other therapies designed for weight loss should focus on more accurate and meaningful assessments of muscle mass, composition, as well as function, mobility or strength, to better define their impact on muscle health for the substantial number of patients who will likely be taking these medications well into the future.

Pharmacotherapy of Weight-loss and Obesity with a Focus on GLP 1-Receptor Agonists

Obesity is a disease of epidemic proportions in the United States and contributes to morbidity and mortality for a large part of the population. In addition, the financial costs of this disease to society are high. Lifestyle modifications are key to prevention and treatment but adherence and long-term success have been challenging. Bariatric surgery has been available and pharmacologic approaches, first developed in the 1950s, continue to be an option; however, existing formulations have not provided optimal clinical efficacy and have had many concerning adverse effects. Over the last decade, glucagon-like peptide-1 (GLP-1) receptor agonists, a novel group of medications for the treatment of type 2 diabetes, were found to produce significant weight loss. Several formulations, at higher doses, received FDA approval for the treatment of obesity or those overweight with weight-related co-morbidities. More hormone-based therapies were and are being developed, some with dual or triple-receptor agonist activity. Their use, however, is not without questions and concerns as to long-term safety and efficacy, problems with cost and reimbursement, and how their use may intersect with public health efforts to manage the obesity epidemic. This review will focus on the GLP-1 receptor agonists currently used for weight loss and discuss their pharmacology, pertinent research findings establishing their benefits and risks, issues with prescribing these medications, and a perspective from a public health point of view.

Metabolic Alteration Bridging the Prediabetic State and Colorectal Cancer

Prediabetes and colorectal cancer (CRC) represent compelling health burdens responsible for high mortality and morbidity rates, sharing several modifiable risk factors. It has been hypothesized that metabolic abnormalities linking prediabetes and CRC are hyperglycemia, hyperinsulinemia, and adipokines imbalance. The chronic stimulation related to these metabolic signatures can favor CRC onset and development, as well as negatively influence CRC prognosis. To date, the growing burden of prediabetes and CRC has generated a global interest in defining their epidemiological and molecular relationships. Therefore, a deeper knowledge of the metabolic impairment determinants is compelling to identify the pathological mechanisms promoting the onset of prediabetes and CRC. In this scenario, this review aims to provide a comprehensive overview on the metabolic alterations of prediabetes and CRC as well as an overview of recent preventive and therapeutic approaches for both diseases, focusing on the role of the metabolic state as a pivotal contributor to consider for the development of future preventive and therapeutic strategies.

A systematic review of the effect of semaglutide on lean mass: insights from clinical trials

INTRODUCTION

Semaglutide, a glucagon-like peptide-1 receptor agonist, is associated with significant weight loss, yet its impact on lean body mass remains insufficiently understood. This review investigates the effect of semaglutide on lean mass in the context of obesity management.

METHODOLOGY

This study investigates through different databases (PubMed, Elsevier, and Google Scholar) from 2016 for randomized control trials (RCTs) or observational studies that assessed the use of semaglutide in overweight or obese patients, regardless of whether they have type 2 diabetes or not. The studies compared semaglutide to a placebo or alternative medications.

RESULTS

Six studies with 1,541 overweight or obese adults were included, and significant weight reductions were observed primarily due to fat mass loss. While the lean mass remained stable in some cases, notable reductions ranging from almost 0% to 40% of total weight reduction were observed in others. Noteworthy decreases in lean mass were particularly evident in larger trials, yet the proportion of lean mass relative to total body mass increased, suggesting a positive overall outcome.

CONCLUSION

Semaglutide displays potential for weight loss primarily through fat mass reduction. However, concerns arise from notable reductions in lean mass, especially in trials with a larger number of patients.

Weight Loss-Independent Effect of Liraglutide on Insulin Sensitivity in Individuals With Obesity and Prediabetes

Metabolic effects of glucagon-like peptide 1 (GLP-1) receptor agonists are confounded by weight loss and not fully recapitulated by increasing endogenous GLP-1. We tested the hypothesis that GLP-1 receptor (GLP-1R) agonists exert weight loss-independent, GLP-1R-dependent effects that differ from effects of increasing endogenous GLP-1. Individuals with obesity and prediabetes were randomized to receive for 14 weeks the GLP-1R agonist liraglutide, a hypocaloric diet, or the dipeptidyl peptidase 4 (DPP-4) inhibitor sitagliptin. The GLP-1R antagonist exendin(9-39) and placebo were administered in a two-by-two crossover study during mixed-meal tests. Liraglutide and diet, but not sitagliptin, caused weight loss. Liraglutide improved insulin sensitivity measured by HOMA for insulin resistance (HOMA-IR), the updated HOMA model (HOMA2), and the Matsuda index after 2 weeks, prior to weight loss. Liraglutide decreased fasting and postprandial glucose levels, and decreased insulin, C-peptide, and fasting glucagon levels. In contrast, diet-induced weight loss improved insulin sensitivity by HOMA-IR and HOMA2, but not the Matsuda index, and did not decrease glucose levels. Sitagliptin increased endogenous GLP-1 and GIP values without altering insulin sensitivity or fasting glucose levels, but decreased postprandial glucose and glucagon levels. Notably, sitagliptin increased GIP without altering weight. Acute GLP-1R antagonism increased glucose levels in all groups, increased the Matsuda index and fasting glucagon level during liraglutide treatment, and increased endogenous GLP-1 values during liraglutide and sitagliptin treatments. Thus, liraglutide exerts rapid, weight loss-independent, GLP-1R-dependent effects on insulin sensitivity that are not achieved by increasing endogenous GLP-1.

ARTICLE HIGHLIGHTS

Metabolic benefits of glucagon-like peptide 1 (GLP-1) receptor agonists are confounded by weight loss and are not fully achieved by increasing endogenous GLP-1 through dipeptidyl peptidase 4 (DPP-4) inhibition. We investigated weight loss-independent, GLP-1 receptor (GLP-1R)-dependent metabolic effects of liraglutide versus a hypocaloric diet or the DPP-4 inhibitor sitagliptin. GLP-1R antagonism with exendin(9-39) was used to assess GLP-1R-dependent effects during mixed meals. Liraglutide improved insulin sensitivity and decreased fasting and postprandial glucose prior to weight loss, and these benefits were reversed by exendin(9-39). GLP-1R agonists exert rapid, weight loss-independent, GLP-1R-dependent effects on insulin sensitivity not achieved by increasing endogenous GLP-1.