Effect of Glucagon-like Peptide-1 Receptor Agonists on Fat Distribution in Patients with Type 2 Diabetes: A Systematic Review and Meta-analysis

Growth differentiation factor 15 is not modified after weight loss induced by liraglutide in South Asians and Europids with type 2 diabetes mellitus

Glucagon-like peptide-1 receptor (GLP-1R) agonists induce weight loss in patients with type 2 diabetes mellitus (T2DM), but the underlying mechanism is unclear. Recently, the mechanism by which metformin induces weight loss could be explained by an increase in growth differentiation factor 15 (GDF15), which suppresses appetite. Therefore, we aimed to investigate whether the GLP-1R agonist liraglutide modifies plasma GDF15 levels in patients with T2DM. GDF15 levels were measured in plasma samples obtained from Dutch Europids and Dutch South Asians with T2DM before and after 26 weeks of treatment with daily liraglutide (n = 44) or placebo (n = 50) added to standard care. At baseline, circulating GDF15 levels did not differ between South Asians and Europids with T2DM. Treatment with liraglutide, compared to placebo, decreased body weight, but did not modify plasma GDF15 levels in all patients, or when data were split by ethnicity. Also, the change in plasma GDF15 levels after treatment with liraglutide did not correlate with changes in body weight or HbA1c levels. In addition, the dose of metformin used did not correlate with baseline plasma GDF15 levels. Compared to placebo, liraglutide treatment for 26 weeks does not modify plasma GDF15 levels in Dutch Europid or South Asian patients with T2DM. Thus, the weight loss induced by liraglutide is likely explained by other mechanisms beyond the GDF15 pathway. HIGHLIGHTS: What is the central question of this study? Growth differentiation factor 15 (GDF15) suppresses appetite and is increased by metformin: does the GLP-1R agonist liraglutide modify plasma GDF15 levels in patients with type 2 diabetes mellitus (T2DM)? What is the main finding and its importance? Plasma GDF15 levels did not differ between South Asians and Europids with T2DM and were not modified by 26 weeks of liraglutide in either ethnicity. Moreover, there was no correlation between the changes in plasma GDF15 levels and dosage of metformin administered, changes in body weight or HbA1c levels. The appetite-suppressing effect of liraglutide is likely exerted via pathways other than GDF15.

Influence of glucagon-like peptide-1 receptor agonists on fat accumulation in patients with diabetes mellitus and non-alcoholic fatty liver disease or obesity: A systematic review and meta-analysis of randomized control trials

AIM

This systematic review and meta-analysis aimed to comprehensively evaluate the impact of glucagon-like peptide 1 receptor agonists (GLP-1RAs) on visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) in individuals with diabetes mellitus and non-alcoholic fatty liver disease (NAFLD) or obesity.

METHODS

A search of PubMed, Embase, and Web of Science until October 2023 identified 13 Randomized Controlled Trials (RCTs) meeting the inclusion criteria. Bias risk was assessed using the Cochrane risk-of-bias instrument. Statistical analysis utilized standard mean differences (SMD) in Review Manager 5.4. Heterogeneity and publication bias were assessed. This study used the protocol registered with the Platform of Registered Systematic Review and Meta-analysis Protocols (INPLASY2023110020).

RESULTS

GLP-1RA treatment significantly reduced VAT (SMD -0.55, 95 % CI [-0.90, -0.19]), SAT (SMD -0.59, 95 % CI [-0.99, -0.19]), body weight (SMD -1.07, 95 % CI [-1.67, -0.47]), and body mass index (BMI) (SMD -1.10, 95 % CI [-1.74, -0.47]) compared to controls. Heterogeneity was observed for VAT (I2 = 79 %, P < 0.01), SAT (I2 = 73 %, P < 0.01), body weight (I2 = 82 %, P < 0.01), and BMI (I2 = 82 %, P < 0.01). No publication bias was detected for VAT (P = 0.57) and SAT (P = 0.18). GLP-1RA treatment improved fasting blood glucose (FBG), postprandial glucose (PPG), hemoglobin A1c (HbA1c), Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), and fibrosis-4 (FIB-4).

CONCLUSIONS

This meta-analysis highlights GLP-1RAs' potential to reduce fat accumulation, body weight, and BMI and improve glycemic control in individuals with diabetes mellitus and NAFLD or obesity. These findings supported using GLP-1RAs as promising therapeutic agents to address abnormal adipose tissue distribution and metabolic dysfunction.

Role of incretins and glucagon receptor agonists in metabolic dysfunction-associated steatotic liver disease: Opportunities and challenges

Metabolic dysfunction-associated steatotic liver disease (MASLD) has become the most common chronic liver disease worldwide, paralleling the rising pandemic of obesity and type 2 diabetes. Due to the growing global health burden and complex pathogenesis of MASLD, a multifaceted and innovative therapeutic approach is needed. Incretin receptor agonists, which were initially developed for diabetes management, have emerged as promising candidates for MASLD treatment. This review describes the pathophysiological mechanisms and action sites of three major classes of incretin/glucagon receptor agonists: glucagon-like peptide-1 receptor agonists, glucose-dependent insulinotropic polypeptide receptor agonists, and glucagon receptor agonists. Incretins and glucagon directly or indirectly impact various organs, including the liver, brain, pancreas, gastrointestinal tract, and adipose tissue. Thus, these agents significantly improve glycemic control and weight management and mitigate MASLD pathogenesis. Importantly, this study provides a summary of clinical trials analyzing the effectiveness and safety of incretin receptor agonists in MASLD management and provides an in-depth analysis highlighting their beneficial effects on improving liver function, hepatic steatosis, and intrahepatic inflammation. There are emerging challenges associated with the use of these medications in the real world, particularly adverse events, drug-drug interactions, and barriers to access, which are discussed in detail. Additionally, this review highlights the evolving role of incretin receptor agonists in MASLD management and suggests future research directions.

Comparative effectiveness of glucagon-like peptide-1 receptor agonists on body composition and anthropometric indices: A protocol for a systematic review and network meta-analysis of randomized controlled trials

BACKGROUND

To date, no studies have addressed the comparative efficacy of glucagon-like peptide-1 receptor agonists (GLP1-RAs) therapy on body composition and anthropometric indices among adult overweight or obese patients with or without type 2 diabetes. To provide evidence-based recommendations, we will conduct a traditional pairwise and network meta-analysis of all available randomized clinical trials that evaluated the effects of GLP1-RAs interventions for adult overweight or obese patients with or without type 2 diabetes.

METHODS AND DESIGN

Electronic databases, including Medline, Embase, PubMed, Cochrane Library (CENTRAL), Scopus, and CINAHL, will be searched from inception without language restriction. Grey literature will be searched, including Google Scholar, ongoing clinical trial registries, and preprint reports. Reference lists of included trials, relevant major endocrinology scientific meetings, and manual hand searches from key general medicine and obesity and endocrinology journals will also be browsed. Two authors will screen, select, extract, appraise the risk of bias, and rate the evidence findings. Any disagreement will be resolved through team discussion. Based on a random-effects model, we will employ a two-step approach of traditional pairwise meta-analysis and network meta-analysis for quantitative synthesis. The pooled effect estimates using a frequentist approach with 95% confidence intervals for continuous endpoints will be expressed as the standardized mean difference, whereas odds ratios will be used for categorical endpoints. The quality of included trials will be evaluated using the Cochrane risk-of-bias version 2 assessment tool. Certainty of evidence for each outcome will be assessed using the modified confidence in network meta-analysis approach and the Grading of Recommended Assessment, Development, and Evaluation approach. The magnitude of the effect size, prediction intervals, surface under the cumulative ranking curve values, and certainty of evidence will be incorporated to draw evidence-based conclusions.

CONCLUSION

This systematic review and network meta-analysis will summarize the comparative efficacy of GLP1-RAs therapy on body composition and anthropometric indices. Evidence identified from this review will promote the rational use of interventions for adult overweight or obese patients with or without type 2 diabetes and will serve as an important step for evidence-based practice within this area.

TRIAL REGISTRATION

PROSPERO registration number: CRD42023458228.

Role of Glucagon-Like Peptide-1 Receptor Agonists on the Weight Loss of Individuals With Type 2 Diabetes: A Systematic Review

Obesity is highly associated with type 2 diabetes mellitus (T2DM), both of which can be simultaneously treated with glucagon-like peptide-1 receptor agonists (GLP-1RAs). There are many antidiabetic drugs that can be used for the treatment of T2DM. These drugs have vast modes of action and therapeutic uses. However, they also have different side effects. Some of these side effects, such as weight changes, are sometimes desirable while others are not. This review examines the literature on how GLP-1RA affects both blood glucose and body weight in patients with T2DM and obesity. In this context, GLP-1RA plays a critical part by controlling not only the blood glucose level but also weight. We followed Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines and searched for articles from PubMed and Google Scholar databases that reported on T2DM, obesity, and GLP-1RA functions. We selected 13 articles that showed the benefits of GLP-1RA in managing both T2DM and obesity. Our review suggests that GLP-1RA is an innovative therapy that can address both conditions simultaneously.

Safety and efficacy of liraglutide on reducing visceral and ectopic fat in adults with or without type 2 diabetes mellitus: A systematic review and meta-analysis

AIM

To assess the efficacy and safety of liraglutide to reduce visceral and ectopic fat in adults with or without type 2 diabetes mellitus (T2DM).

METHODS

Four databases were searched up to 6 May 2022 for randomized clinical trials assessing the effect of liraglutide on visceral and ectopic fat. The mean and standard deviation of the values of visceral fat, ectopic fat and body mass index were calculated. Subgroup analyses were performed based on the type of disease (T2DM or non-T2DM), duration of intervention, dosage of liraglutide and whether life interventions were added to liraglutide therapy. We extracted and integrated the safety assessments reported in each article.

RESULTS

Sixteen randomized clinical trials with, in total, 845 participants were included in the meta-analysis. Liraglutide could significantly decrease visceral fat [standard mean difference (SMD) = -0.72, 95% confidence interval (CI; -1.12, -0.33)], liver fat [SMD = -0.78, 95% CI (-1.24, -0.32)] and body mass index [weighted mean difference = -1.44, 95% CI (-1.95, -0.92)] in adult patients with or without T2DM when compared with the control group. However, reduction of epicardial fat by liraglutide [SMD = -0.74, 95% CI (-1.82, 0.34)] was not statistically significant. Subgroup analysis revealed that an adequate dosage (≥1.8 mg/day) and appropriate duration of treatment (ranging from 16 to 40 weeks) were the decisive factors for liraglutide to reduce visceral fat effectively. Mild gastrointestinal reactions were the main adverse event of liraglutide.

CONCLUSIONS

Liraglutide significantly and safely reduces visceral and ectopic liver fat irrespective of T2DM status, and reduces visceral fat provided adequate dosage and duration of therapy are ensured.

Updates of incretin-related drugs for the treatment of type 2 diabetes

Mechanisms of dipeptidyl peptidase-4 inhibitors, glucagon-like peptide-1 receptor agonists and glucagon-like peptide-1 receptor/glucose-dependent insulinotropic polypeptide receptor dual-agonist in glycemic control and/or weight loss.