Glucagon increases energy expenditure independently of brown adipose tissue activation in humans

Dietary protein defends lean mass and maintains the metabolic benefits of glucagon receptor agonism in mice

OBJECTIVE

Glucagon has long been proposed as a component of multi-agonist obesity therapeutics due to its ability to induce energy expenditure and cause weight loss. However, chronic glucagon-receptor agonism has been associated with a reduction in circulating amino acids and loss of lean mass. Importantly, it is currently not known whether the metabolic benefits of glucagon can be maintained under contexts that allow the defence of lean mass.

METHODS

We investigate the metabolic effects of the long-acting glucagon receptor agonist, G108, when administered to obese mice at low-doses, and with dietary protein supplementation.

RESULTS

Dietary protein supplementation can only fully defend lean mass at a low dose of G108 that is sub-anorectic and does not reduce fat mass. However, in this context, G108 is still highly effective at improving glucose tolerance and reducing liver fat in obese mice. Mechanistically, liver RNA-Seq analysis reveals that dietary protein supplementation defends anabolic processes in low-dose G108-treated mice, and its effects on treatment-relevant glucose and lipid pathways are preserved.

CONCLUSION

Glucagon-mediated energy expenditure and weight loss may be mechanistically coupled to hypoaminocidemia and lean mass loss. However, our data suggest that glucagon can treat MAFLD at doses which allow full defence of lean mass given sufficient dietary protein intake. Therefore, proportionate glucagon therapy may be safe and effective in targeting hepatocytes and improving in glycaemia and liver fat.

The role of incretin receptor agonists in the treatment of obesity

INTRODRODUCTION

Obesity and its associated metabolic conditions have become a significant global health problem in recent years, with many people living with obesity fulfilling criteria for pharmacological treatment. The development of the glucagon-like peptide-1 receptor agonists for chronic weight management has triggered new interest in the incretins and other hormones as targets for obesity, and investigations into dual and triple co-agonists.

METHODS

The objective of this narrative review was to summarize the available data on approved and emerging incretin-based agents for the treatment of obesity.

RESULTS

In clinical trials of currently available agents in people with overweight or obesity, weight loss of between 6% and 21% of baseline body weight has been observed, with between 23% and 94% of participants achieving 10% or higher weight loss, depending on the study and the agent used. Favourable outcomes have also been seen with regard to cardiovascular risk and outcomes, diabetes prevention, metabolic dysfunction-associated steatotic liver disease/steatohepatitis and prevention of weight regain after metabolic surgery. Limitations associated with these agents include high costs, the potential for weight regain once treatment is stopped, the potential loss of lean body mass and gastrointestinal adverse events; potential issues with respect to gallbladder and biliary diseases require further investigation.

CONCLUSIONS

Many dual and triple co-agonists are still in development, and more data are needed to assess the efficacy, safety and tolerability of these emerging therapies versus the established incretin-based therapies; however, data are promising, and further results are eagerly awaited.

Larval density can be used to predict genetic modifiers of glucagon signaling in Drosophila melanogaster

Obesity is a growing concern. 42.3% of people in the U.S were considered obese between 2017-2018. Much is still unknown about the genetic components that contribute to weight gain. In humans, the hormone glucagon is a major contributor to the body's energy regulation as it signals for the breakdown of lipids. Treatments targeting the glucagon pathway have helped patients with both weight loss and appetite suppression. Understanding the genetic modifiers of glucagon signaling and its downstream pathways could enable the development of a wider variety of effective therapeutics. In this study, we blocked the glucagon pathway in Drosophila melanogaster by reducing the expression of the fly ortholog of the glucagon receptor (AKHR). We then crossed our model to the Drosophila Genetic Reference Panel (DGRP) and looked for natural variation in fat content. We used variation in larval density to identify candidate modifier genes through a genome-wide association study. We then tested these modifier genes by increasing or decreasing their expression in the AKHR model. We screened these candidates initially with the same density assay used in the original study to narrow down to four candidate genes that substantially impacted the density of the larvae: THADA, AmyD, GluRIIC, and CG9826. We further characterized these candidates using biochemical assays to analyze stored metabolites such as triglycerides, glucose, glycogen, and protein under control, high sugar, and high fat conditions to see if the larvae are resistant to environmental changes. Our results indicate consistency between the results of the density assay and direct measurement of metabolite levels. In particular, THADA and AmyD are highlighted as interesting genes for additional study. We hope to improve our understanding of the glucagon signaling pathway, obesity, and lipid metabolism. We also aim to provide candidate genes that can be regarded as future therapeutic targets.

Targeting the incretin system in obesity and type 2 diabetes mellitus

Obesity and type 2 diabetes mellitus (T2DM) are widespread, non-communicable diseases that are responsible for considerable levels of morbidity and mortality globally, primarily in the form of cardiovascular disease (CVD). Changes to lifestyle and behaviour have insufficient long-term efficacy in most patients with these diseases; metabolic surgery, although effective, is not practically deliverable on the scale that is required. Over the past two decades, therapies based on incretin hormones, spearheaded by glucagon-like peptide 1 (GLP1) receptor agonists (GLP1RAs), have become the treatment of choice for obesity and T2DM, and clinical evidence now suggests that these agents have benefits for CVD. We review the latest advances in incretin-based pharmacotherapy. These include 'GLP1 plus' agents, which combine the known advantages of GLP1RAs with the activity of additional hormones, such as glucose-dependent insulinotropic peptide, glucagon and amylin, to achieve desired therapeutic goals. Second-generation non-peptidic oral GLP1RAs promise to extend the benefits of GLP1 therapy to those who do not want, or cannot have, subcutaneous injection therapy. We conclude with a discussion of the knowledge gaps that must be addressed before incretin-based therapies can be properly deployed for maximum benefit in the treatment of obesity and T2DM.

Molecular Mechanisms behind Obesity and Their Potential Exploitation in Current and Future Therapy

Obesity is a chronic disease caused primarily by the imbalance between the amount of calories supplied to the body and energy expenditure. Not only does it deteriorate the quality of life, but most importantly it increases the risk of cardiovascular diseases and the development of type 2 diabetes mellitus, leading to reduced life expectancy. In this review, we would like to present the molecular pathomechanisms underlying obesity, which constitute the target points for the action of anti-obesity medications. These include the central nervous system, brain-gut-microbiome axis, gastrointestinal motility, and energy expenditure. A significant part of this article is dedicated to incretin-based drugs such as GLP-1 receptor agonists (e.g., liraglutide and semaglutide), as well as the brand new dual GLP-1 and GIP receptor agonist tirzepatide, all of which have become "block-buster" drugs due to their effectiveness in reducing body weight and beneficial effects on the patient's metabolic profile. Finally, this review article highlights newly designed molecules with the potential for future obesity management that are the subject of ongoing clinical trials.

GPCR-mediated regulation of beige adipocyte formation: Implications for obesity and metabolic health

Obesity and its associated complications pose a significant burden on health. The non-shivering thermogenesis (NST) and metabolic capacity properties of brown adipose tissue (BAT), which are distinct from those of white adipose tissue (WAT), in combating obesity and its related metabolic diseases has been well documented. However, beige adipose tissue, the third and relatively novel type of adipose tissue, which emerges in extensive presence of WAT and shares similar favorable metabolic properties with BAT, has garnered considerable attention in recent years. In this review, we focused on the role of G protein-coupled receptors (GPCRs), the largest receptor family and the most successful class of drug targets in humans, in the induction of beige adipocytes. More importantly, we highlight researchers' clinical treatment attempts to ameliorate obesity and other related metabolic diseases through the formation and activation of beige adipose tissue. In summary, this review provides valuable insights into the formation of beige adipose tissue and the involvement of GPCRs, based on the latest advancements in scientific research.

Dual glucagon-like peptide-1 and glucagon receptor agonism reduces energy intake in type 2 diabetes with obesity

AIMS

To establish which components of energy balance mediate the clinically significant weight loss demonstrated with use of cotadutide, a glucagon-like peptide-1 (GLP-1)/glucagon receptor dual agonist, in early-phase studies.

MATERIALS AND METHODS

We conducted a phase 2a, single-centre, randomized, placebo-controlled trial in overweight and obese adults with type 2 diabetes. Following a 16-day single-blind placebo run-in, participants were randomized 2:1 to double-blind 42-day subcutaneous treatment with cotadutide (100-300 μg daily) or placebo. The primary outcome was percentage weight change. Secondary outcomes included change in energy intake (EI) and energy expenditure (EE).

RESULTS

A total of 12 participants (63%) in the cotadutide group and seven (78%) in the placebo group completed the study. The mean (90% confidence interval [CI]) weight change was -4.0% (-4.9%, -3.1%) and -1.4% (-2.7%, -0.1%) for the cotadutide and placebo groups, respectively (p = 0.011). EI was lower with cotadutide versus placebo (-41.3% [-66.7, -15.9]; p = 0.011). Difference in EE (per kJ/kg lean body mass) for cotadutide versus placebo was 1.0% (90% CI -8.4, 10.4; p = 0.784), assessed by doubly labelled water, and -6.5% (90% CI -9.3, -3.7; p < 0.001), assessed by indirect calorimetry.

CONCLUSION

Weight loss with cotadutide is primarily driven by reduced EI, with relatively small compensatory changes in EE.

The dual GCGR/GLP-1R agonist survodutide: Biomarkers and pharmacological profiling for clinical candidate selection

AIM

To describe the biomarker strategy that was applied to select survodutide (BI 456906), BI 456908 and BI 456897 from 19 dual glucagon receptor (GCGR)/ glucagon-like peptide-1 receptor (GLP-1R) agonists for in-depth pharmacological profiling, which led to the qualification of survodutide as the clinical development candidate.

MATERIALS AND METHODS

Potencies to increase cyclic adenosine monophosphate (cAMP) were determined in Chinese hamster ovary (CHO)-K1 cells stably expressing human GCGR and GLP-1R. Agonism for endogenously expressed receptors was investigated in insulinoma cells (MIN6) for mouse GLP-1R, and in rat primary hepatocytes for the GCGR. In vivo potencies to engage the GLP-1R or GCGR were determined, measuring improvement in oral glucose tolerance (30 nmol/kg) and increase in plasma fibroblast growth factor-21 (FGF21) and liver nicotinamide N-methyltransferase (NNMT) mRNA expression (100 nmol/kg), respectively. Body weight- and glucose-lowering efficacies were investigated in diet-induced obese (DIO) mice and diabetic db/db mice, respectively.

RESULTS

Upon acute dosing in lean mice, target engagement biomarkers for the GCGR and GLP-1R demonstrated a significant correlation (Spearman correlation coefficient with p < 0.05) to the in vitro GCGR and GLP-1R potencies for the 19 dual agonists investigated. Survodutide, BI 456908 and BI 456897 were selected for in-depth pharmacological profiling based on the significant improvement in acute oral glucose tolerance achieved (area under the curve [AUC] of 54%, 57% and 60% vs. vehicle) that was comparable to semaglutide (AUC of 45% vs. vehicle), while showing different degrees of in vivo GCGR engagement, as determined by hepatic NNMT mRNA expression (increased by 15- to 17-fold vs. vehicle) and plasma FGF21 concentrations (increased by up to sevenfold vs. vehicle). In DIO mice, survodutide (30 nmol/kg/once daily), BI 456908 (30 nmol/kg/once daily) and BI 456897 (10 nmol/kg/once daily) achieved a body weight-lowering efficacy from baseline of 25%, 27% and 26%, respectively. In db/db mice, survodutide and BI 456908 (10 and 20 nmol/kg/once daily) significantly lowered glycated haemoglobin (0.4%-0.6%); no significant effect was observed for BI 456897 (3 and 7 nmol/kg/once daily).

CONCLUSIONS

Survodutide was selected as the clinical candidate based on its balanced dual GCGR/GLP-1R pharmacology, engaging the GCGR for robust body weight-lowering efficacy exceeding that of selective GLP-1R agonists, while achieving antidiabetic efficacy that was comparable to selective GLP-1R agonism. Survodutide is currently being investigated in Phase 3 clinical trials in people living with obesity.

Glucagon resistance and metabolic-associated steatotic liver disease: a review of the evidence

Metabolic-associated steatotic liver disease (MASLD) is closely associated with obesity. MASLD affects over 1 billion adults globally but there are few treatment options available. Glucagon is a key metabolic regulator, and its actions include the reduction of liver fat through direct and indirect means. Chronic glucagon signalling deficiency is associated with hyperaminoacidaemia, hyperglucagonaemia and increased circulating levels of glucagon-like peptide 1 (GLP-1) and fibroblast growth factor 21 (FGF-21). Reduction in glucagon activity decreases hepatic amino acid and triglyceride catabolism; metabolic effects include improved glucose tolerance, increased plasma cholesterol and increased liver fat. Conversely, glucagon infusion in healthy volunteers leads to increased hepatic glucose output, decreased levels of plasma amino acids and increased urea production, decreased plasma cholesterol and increased energy expenditure. Patients with MASLD share many hormonal and metabolic characteristics with models of glucagon signalling deficiency, suggesting that they could be resistant to glucagon. Although there are few studies of the effects of glucagon infusion in patients with obesity and/or MASLD, there is some evidence that the expected effect of glucagon on amino acid catabolism may be attenuated. Taken together, this evidence supports the notion that glucagon resistance exists in patients with MASLD and may contribute to the pathogenesis of MASLD. Further studies are warranted to investigate the direct effects of glucagon on metabolism in patients with MASLD.

Oral glucagon-like peptide-1 receptor agonists and combinations of entero-pancreatic hormones as treatments for adults with type 2 diabetes: where are we now?

INTRODUCTION

Glucagon-like peptide-1 (GLP-1) receptor agonists (RAs) have changed the landscape of type 2 diabetes (T2D) management due to their cardio-renal benefits, their glucose-lowering efficacy and weight loss (WL) maintenance. However, the response to GLP-1 RA monotherapy is heterogeneous. Additionally, the majority of GLP-1 RAs are injectable treatments. Oral GLP-1 RAs and injectable combinations of GLP-1 with other entero-pancreatic hormones (glucose-dependent insulinotropic polypeptide (GIP), glucagon and amylin) are under development for T2D and obesity management.

AREAS COVERED

Herein, we review the data on (i) oral GLP-1 RAs (oral semaglutide 25/50 mg and orforglipron) and (ii) dual/triple agonists (tirzepatide, cagrilintide 2.4 mg/semaglutide 2.4 mg, survodutide, mazdutide, retatrutide) that have recently completed phase 3 trials for T2D or are currently in phase 3 clinical trials. Tirzepatide is the first approved dual agonist (GLP-1/GIP) for T2D and obesity management.

EXPERT OPINION

We are in a new era in T2D management where entero-pancreatic hormone-based treatments can result in ≥15% WL and euglycemia for many people with T2D. Multiple molecules with different mechanisms of action are under development for T2D, obesity and other metabolic complications. Data on their cardio-renal benefits, long-term efficacy and safety as well as their cost-effectiveness will better inform their position in treatment algorithms.

Dose-response effects on HbA1c and bodyweight reduction of survodutide, a dual glucagon/GLP-1 receptor agonist, compared with placebo and open-label semaglutide in people with type 2 diabetes: a randomised clinical trial

AIMS/HYPOTHESIS

The aim of this study was to assess the dose-response effects of the subcutaneous glucagon receptor/glucagon-like peptide-1 receptor dual agonist survodutide (BI 456906) on HbA1c levels and bodyweight reduction.

METHODS

This Phase II, multicentre, randomised, double-blind, parallel-group, placebo-controlled study, conducted in clinical research centres, assessed survodutide in participants aged 18-75 years with type 2 diabetes, an HbA1c level of 53-86 mmol/mol (7.0-10.0%) and a BMI of 25-50 kg/m2 on a background of metformin therapy. Participants were randomised via interactive response technology to receive survodutide (up to 0.3, 0.9, 1.8 or 2.7 mg once weekly [qw; dose group (DG) 1-4, respectively] or 1.2 or 1.8 mg twice weekly [DG 5 and 6, respectively]), placebo or semaglutide (up to 1.0 mg qw). Participants and all those involved in the trial conduct/analysis were blinded; the semaglutide arm was open-label. The primary endpoint was absolute change from baseline in HbA1c after 16 weeks' treatment. The key secondary endpoint was relative change from baseline in bodyweight after 16 weeks' treatment.

RESULTS

A total of 413 participants were randomised (DG1, n=50; DG2, n=50; DG3, n=52; DG4, n=50; DG5, n=51; DG6, n=50; semaglutide, n=50; placebo, n=60). The full analysis set comprised 411 treated participants (DG6, n=49; placebo, n=59). Adjusted mean (95% CI) HbA1c decreased from baseline (mean ± SD 64.7±9.2 mmol/mol [8.07±0.84%] after 16 weeks' treatment: DG1 (n=41), -9.92 mmol/mol (-12.27, -7.56; -0.91% [-1.12, -0.69]); DG2 (n=46), -15.95 mmol/mol (-18.27, -13.63; -1.46% [-1.67, -1.25]); DG3 (n=36), -18.72 mmol/mol (-21.15, -16.29; -1.71% [-1.94, -1.49]); DG4 (n=33), -17.01 mmol/mol (-19.59, -14.43; -1.56% [-1.79, -1.32]); DG5 (n=44), -17.84 mmol/mol (-20.18, -15.51; -1.63% [-1.85, -1.42]); DG6 (n=36), -18.38 mmol/mol (-20.90, -15.87; -1.68% [-1.91, -1.45]). The mean reduction in HbA1c was similar with low-dose survodutide (DG2: -15.95 mmol/mol [-1.46%]; n=46) and semaglutide (-16.07 mmol/mol [-1.47%]; n=45). Mean (95% CI) bodyweight decreased dose-dependently up to -8.7% (-10.1, -7.3; DG6, n=37); survodutide ≥1.8 mg qw produced greater bodyweight reductions than semaglutide (-5.3% [-6.6, -4.1]; n=45). Adverse events (AEs) were reported for 77.8% of survodutide-treated participants (mainly gastrointestinal), 52.5% receiving placebo and 52.0% receiving semaglutide.

CONCLUSIONS/INTERPRETATION

Survodutide reduced HbA1c levels and bodyweight after 16 weeks' treatment in participants with type 2 diabetes. Dose-related gastrointestinal AEs could be mitigated with slower dose escalations.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04153929 and EudraCT 2019-002390-60.

FUNDING

Boehringer Ingelheim Pharma GmbH & Co. KG, Ingelheim, Germany.

Glucagon and GLP-1 receptor dual agonist survodutide for obesity: a randomised, double-blind, placebo-controlled, dose-finding phase 2 trial

BACKGROUND

Obesity is a widespread and chronic condition that requires long-term management; research into additional targets to improve treatment outcomes remains a priority. This study aimed to investigate the safety, tolerability, and efficacy of glucagon receptor-GLP-1 receptor dual agonist survodutide (BI 456906) in obesity management.

METHODS

In this randomised, double-blind, placebo-controlled, dose-finding phase 2 trial conducted in 43 centres in 12 countries, we enrolled participants (aged 18-75 years, BMI ≥27 kg/m2, without diabetes) and randomly assigned them by interactive response technology (1:1:1:1:1; stratified by sex) to subcutaneous survodutide (0·6, 2·4, 3·6, or 4·8 mg) or placebo once-weekly for 46 weeks (20 weeks dose escalation; 26 weeks dose maintenance). The primary endpoint was the percentage change in bodyweight from baseline to week 46. Primary analysis included the modified intention-to-treat population (defined as all randomly assigned patients who received at least one dose of trial medication and who had analysable data for at least one efficacy endpoint) and was based on the dose assigned at randomisation (planned treatment), including all data censored for COVID-19-related discontinuations; the sensitivity analysis was based on the actual dose received during maintenance phase (actual treatment) and included on-treatment data. Safety analysis included all participants who received at least one dose of study drug. The trial is registered with ClinicalTrials.gov (NCT04667377) and EudraCT (2020-002479-37).

FINDINGS

Between March 30, 2021, and Nov 11, 2021, we enrolled 387 participants; 386 (100%) participants were treated (0·6 mg, n=77; 2·4 mg, n=78; 3·6 mg, n=77; 4·8 mg, n=77; placebo n=77) and 233 (60·4%) of 386 completed the 46-week treatment period (187 [61%] of 309 receiving survodutide; 46 [60%] of 77 receiving placebo). When analysed according to planned treatment, mean (95% CI) changes in bodyweight from baseline to week 46 were -6·2% (-8·3 to -4·1; 0·6 mg); -12·5% (-14·5 to -10·5; 2·4 mg); -13·2% (-15·3 to -11·2; 3·6 mg); -14·9% (-16·9 to -13·0; 4·8 mg); -2·8% (-4·9 to -0·7; placebo). Adverse events occurred in 281 (91%) of 309 survodutide recipients and 58 (75%) of 77 placebo recipients; these were primarily gastrointestinal in 232 (75%) of 309 survodutide recipients and 32 (42%) of 77 placebo recipients.

INTERPRETATION

All tested survodutide doses were tolerated, and dose-dependently reduced bodyweight.

FUNDING

Boehringer Ingelheim.

Efficacy and safety of Mazdutide on weight loss among diabetic and non-diabetic patients: a systematic review and meta-analysis of randomized controlled trials

Background

Overweight and obesity are increasing global public health problems. Mazdutide is a new dual agonist drug that can potentially reduce weight and blood glucose levels simultaneously. However, the synthesis of evidence on the efficacy and safety of this drug is scarce. Therefore, this study aimed to synthesize evidence on the efficacy and safety of Mazdutide compared to placebo on weight reduction among adults with and without diabetes.

Methods

We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs). Data were retrieved from six electronic databases: PubMed, Web of Science, Scopus, Cochrane Library, ClinicalTrial.gov, and Google Scholar, and manually searched from the included references. The data were synthesized using a random effect model. This analysis was performed in the R programming language using the Meta package.

Results

A total of seven RCTs involving 680 participants were included in this study. Mazdutide was more effective in reducing body weight (mean difference [MD]= -6.22%, 95% confidence interval [CI]: -8.02% to -4.41%, I2 = 90.0%), systolic blood pressure (MD = -7.57 mmHg, 95% CI: -11.17 to -3.98 mmHg, I2 = 46%), diastolic blood pressure (MD = -2.98 mmHg, 95% CI: -5.74 to -0.22 mmHg, I2 = 56%), total cholesterol (MD = -16.82%, 95% CI: -24.52 to -9.13%, I2 = 61%), triglycerides (MD = -43.29%, 95% CI: -61.57 to -25.01%, I2 = 68%), low-density lipoprotein (MD= -17.07%, 95% CI: -25.54 to -8.60%, I2 = 53%), and high-density lipoprotein (MD = -7.54%, 95% CI: -11.26 to -3.83%, I2 = 0%) than placebo. Mazdutide was associated with reduced hemoglobin A1c (HbA1c) and fasting plasma glucose in participants with type 2 diabetes. In the subgroup and meta-regression analyses, weight reduction was more significant in non-diabetics compared to diabetics, and in those who received a longer treatment duration (24 weeks) than in those on shorter durations (12-20 weeks). Participants who received Mazdutide had a higher risk of transient mild or moderate gastrointestinal side effects.

Conclusion

Mazdutite appears to be effective in weight reduction among patients with and without diabetes, and it has an advantage over other associated comorbidities. However, it was associated with mild or moderate gastrointestinal side effects.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=403859, identifier CRD42023403859.

What is the pipeline for future medications for obesity?

Obesity is a chronic disease associated with increased risk of obesity-related complications and mortality. Our better understanding of the weight regulation mechanisms and the role of gut-brain axis on appetite has led to the development of safe and effective entero-pancreatic hormone-based treatments for obesity such as glucagon-like peptide-1 (GLP-1) receptor agonists (RA). Semaglutide 2.4 mg once weekly, a subcutaneously administered GLP-1 RA approved for obesity treatment in 2021, results in 15-17% mean weight loss (WL) with evidence of cardioprotection. Oral GLP-1 RA are also under development and early data shows similar WL efficacy to semaglutide 2.4 mg. Looking to the next generation of obesity treatments, combinations of GLP-1 with other entero-pancreatic hormones with complementary actions and/or synergistic potential (such as glucose-dependent insulinotropic polypeptide (GIP), glucagon, and amylin) are under investigation to enhance the WL and cardiometabolic benefits of GLP-1 RA. Tirzepatide, a dual GLP-1/GIP receptor agonist has been approved for glycaemic control in type 2 diabetes as well as for obesity management leading in up to 22.5% WL in phase 3 obesity trials. Other combinations of entero-pancreatic hormones including cagrisema (GLP-1/amylin RA) and the triple agonist retatrutide (GLP-1/GIP/glucagon RA) have also progressed to phase 3 trials as obesity treatments and early data suggests that may lead to even greater WL than tirzepatide. Additionally, agents with different mechanisms of action to entero-pancreatic hormones (e.g. bimagrumab) may improve the body composition during WL and are in early phase clinical trials. We are in a new era for obesity pharmacotherapy where combinations of entero-pancreatic hormones approach the WL achieved with bariatric surgery. In this review, we present the efficacy and safety data for the pipeline of obesity pharmacotherapies with a focus on entero-pancreatic hormone-based treatments and we consider the clinical implications and challenges that the new era in obesity management may bring.

Poly-Agonist Pharmacotherapies for Metabolic Diseases: Hopes and New Challenges

The use of glucagon-like peptide-1 (GLP-1) receptor-based multi-agonists in the treatment of type 2 diabetes and obesity holds great promise for improving glycaemic control and weight management. Unimolecular dual and triple agonists targeting multiple gut hormone-related pathways are currently in clinical trials, with recent evidence supporting their efficacy. However, significant knowledge gaps remain regarding the biological mechanisms and potential adverse effects associated with these multi-target agents. The mechanisms underlying the therapeutic efficacy of GLP-1 receptor-based multi-agonists remain somewhat mysterious, and hidden threats may be associated with the use of gut hormone-based polyagonists. In this review, we provide a critical analysis of the benefits and risks associated with the use of these new drugs in the management of obesity and diabetes, while also exploring new potential applications of GLP-1-based pharmacology beyond the field of metabolic disease.

Revisiting Resting Metabolic Rate: What is the Relation to Weight Fluctuations?

PURPOSE OF REVIEW

Despite the great progress in obesity-tackling strategies, a negative energy equilibrium between energy expenditure and energy intake remains the cornerstone in obesity management. The present review article aims to shed light on the complicated interrelations of resting metabolic rate to weight fluctuations.

RECENT FINDINGS

Energy expenditure depends on body composition and is highly affected by weight changes, exerting a significant role in subsequent weight regain and underlining the metabolic resistance that people with obesity face when dealing with weight maintenance. The main tissue involved in energy expenditure is fat-free mass, as opposed to fat mass, which exerts a substantially lower impact. Although people with obesity display higher energy expenditures than their lean counterparts, these decrease substantially in the setting of weight loss. Metabolic adaptation is the difference between measured and predicted RMR after weight loss, either via lifestyle modification or after obesity surgery. Plausible explanations for this include differences in body composition, with loss of fat-free mass playing a significant role. This becomes especially apparent in the setting of rapid and massive weight loss, as in the case of bariatric surgery. A better understanding of energy expenditure pathophysiology may aid in further enhancing weight loss and promoting weight maintenance in people with obesity.

Pharmacological modulation of adaptive thermogenesis: new clues for obesity management?

BACKGROUND

Adaptive thermogenesis represents the main mechanism through which the body generates heat in response to external stimuli, a phenomenon that includes shivering and non-shivering thermogenesis. The non-shivering thermogenesis is mainly exploited by adipose tissue characterized by a brown aspect, which specializes in energy dissipation. A decreased amount of brown adipose tissue has been observed in ageing and chronic illnesses such as obesity, a worldwide health problem characterized by dysfunctional adipose tissue expansion and associated cardiometabolic complications. In the last decades, the discovery of a trans-differentiation mechanism ("browning") within white adipose tissue depots, leading to the generation of brown-like cells, allowed to explore new natural and synthetic compounds able to favour this process and thus enhance thermogenesis with the aim of counteracting obesity. Based on recent findings, brown adipose tissue-activating agents could represent another option in addition to appetite inhibitors and inhibitors of nutrient absorption for obesity treatment.

PURPOSE

This review investigates the main molecules involved in the physiological (e.g. incretin hormones) and pharmacological (e.g. β3-adrenergic receptors agonists, thyroid receptor agonists, farnesoid X receptor agonists, glucagon-like peptide-1, and glucagon receptor agonists) modulation of adaptive thermogenesis and the signalling mechanisms involved.

Effect of high-dose glucocorticoid treatment on human brown adipose tissue activity: a randomised, double-blinded, placebo-controlled cross-over trial in healthy men

BACKGROUND

Glucocorticoids (GCs) are widely applied anti-inflammatory drugs that are associated with adverse metabolic effects including insulin resistance and weight gain. Previous research indicates that GCs may negatively impact brown adipose tissue (BAT) activity in rodents and humans.

METHODS

We performed a randomised, double-blinded cross-over trial in 16 healthy men (clinicaltrials.govNCT03269747). Participants received 40 mg of prednisone per day for one week or placebo. After a washout period of four weeks, participants crossed-over to the other treatment arm. Primary endpoint was the increase in resting energy expenditure (EE) in response to a mild-cold stimulus (cold-induced thermogenesis, CIT). Secondary outcomes comprised mean 18F-FDG uptake into supraclavicular BAT (SUVmean) as determined by FDG-PET/CT, volume of the BAT depot as well as fat content determined by MRI. The plasma metabolome and the transcriptome of supraclavicular BAT and of skeletal muscle biopsies after each treatment period were analysed.

FINDINGS

Sixteen participants were recruited to the trial and completed it successfully per protocol. After prednisone treatment resting EE was higher both during warm and cold conditions. However, CIT was similar, 153 kcal/24 h (95% CI 40-266 kcal/24 h) after placebo and 186 kcal/24 h (95% CI 94-277 kcal/24 h, p = 0.38) after prednisone. SUVmean of BAT after cold exposure was not significantly affected by prednisone (3.36 g/ml, 95% CI 2.69-4.02 g/ml, vs 3.07 g/ml, 95% CI 2.52-3.62 g/ml, p = 0.28). Results of plasma metabolomics and BAT transcriptomics corroborated these findings. RNA sequencing of muscle biopsies revealed higher expression of genes involved in calcium cycling. No serious adverse events were reported and adverse events were evenly distributed between the two treatments.

INTERPRETATION

Prednisone increased EE in healthy men possibly by altering skeletal muscle calcium cycling. Cold-induced BAT activity was not affected by GC treatment, which indicates that the unfavourable metabolic effects of GCs are independent from thermogenic adipocytes.

FUNDING

Grants from Swiss National Science Foundation (PZ00P3_167823), Bangerter-Rhyner Foundation and from Nora van der Meeuwen-Häfliger Foundation to MJB. A fellowship-grant from the Swiss National Science Foundation (SNF211053) to WS. Grants from German Research Foundation (project number: 314061271-TRR 205) and Else Kröner-Fresenius (grant support 2012_A103 and 2015_A228) to MR.

Amino acids contribute to adaptive thermogenesis. New insights into the mechanisms of action of recent drugs for metabolic disorders are emerging

Adaptive thermogenesis is the heat production by muscle contractions (shivering thermogenesis) or brown adipose tissue (BAT) and beige fat (non-shivering thermogenesis) in response to external stimuli, including cold exposure. BAT and beige fat communicate with peripheral organs and the brain through a variegate secretory and absorption processes - controlling adipokines, microRNAs, extracellular vesicles, and metabolites - and have received much attention as potential therapeutic targets for managing obesity-related disorders. The sympathetic nervous system and norepinephrine-releasing adipose tissue macrophages (ATM) activate uncoupling protein 1 (UCP1), expressed explicitly in brown and beige adipocytes, dissolving the electrochemical gradient and uncoupling tricarboxylic acid cycle and the electron transport chain from ATP production. Mounting evidence has attracted attention to the multiple effects of dietary and endogenously synthesised amino acids in BAT thermogenesis and metabolic phenotype in animals and humans. However, the mechanisms implicated in these processes have yet to be conclusively characterized. In the present review article, we aim to define the principal investigation areas in this context, including intestinal microbiota constitution, adipose autophagy modulation, and secretome and metabolic fluxes control, which lead to increased brown/beige thermogenesis. Finally, also based on our recent epicardial adipose tissue results, we summarise the evidence supporting the notion that the new dual and triple agonists of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and glucagon (GCG) receptor - with never before seen weight loss and insulin-sensitizing efficacy - promote thermogenic-like amino acid profiles in BAT with robust heat production and likely trigger sympathetic activation and adaptive thermogenesis by controlling amino acid metabolism and ATM expansion in BAT and beige fat.

Retatrutide: a triple incretin receptor agonist for obesity management

INTRODUCTION

Obesity treatment is evolving rapidly with the emergence of agents targeting incretin receptors. Retatrutide, a triple agonist of these receptors, shows promise in obesity management.

AREAS COVERED

Retatrutide, in phase-2 trials, exhibited significant reductions in glycated hemoglobin (HbA1c) and dose-dependent weight loss in individuals with type 2 diabetes mellitus (T2DM). In non-T2DM individuals, it produced substantial weight loss and improved glucose levels, albeit with gastrointestinal side effects. The role of glucagon receptor agonism in the management of heart failure and its potential impact on eating patterns have also been covered in this article.

EXPERT OPINION

Although the reductions in HbA1c and dose-dependent weight loss among individuals with T2DM were significantly more for higher doses of retatrutide, it needs to be observed that the active comparator was dulaglutide, which is not approved for the treatment of obesity, at a dose of 1.5 mg, which is much lower than the highest approved dose of 4.5 mg. Dose-dependent increase in heart rate and incidents of mild to moderate cardiac arrythmias raise cardiovascular safety concerns and signify that carrying out long-term cardiovascular outcome trials (CVOTs) will be critical. In addition, retatrutide's potential in heart failure management is intriguing given the series of positive findings of semaglutide on cardiovascular outcomes.

Gut hormone co-agonists for the treatment of obesity: from bench to bedside

The discovery and development of so-called gut hormone co-agonists as a new class of drugs for the treatment of diabetes and obesity is considered a transformative breakthrough in the field. Combining action profiles of multiple gastrointestinal hormones within a single molecule, these novel therapeutics achieve synergistic metabolic benefits. The first such compound, reported in 2009, was based on balanced co-agonism at glucagon and glucagon-like peptide-1 (GLP-1) receptors. Today, several classes of gut hormone co-agonists are in development and advancing through clinical trials, including dual GLP-1-glucose-dependent insulinotropic polypeptide (GIP) co-agonists (first described in 2013), and triple GIP-GLP-1-glucagon co-agonists (initially designed in 2015). The GLP-1-GIP co-agonist tirzepatide was approved in 2022 by the US Food and Drug Administration for the treatment of type 2 diabetes, providing superior HbA1c reductions compared to basal insulin or selective GLP-1 receptor agonists. Tirzepatide also achieved unprecedented weight loss of up to 22.5%-similar to results achieved with some types of bariatric surgery-in non-diabetic individuals with obesity. In this Perspective, we summarize the discovery, development, mechanisms of action and clinical efficacy of the different types of gut hormone co-agonists, and discuss potential challenges, limitations and future developments.

Looking ahead to potential incretin combination therapies for non-alcoholic steatohepatitis in patients with diabetes

INTRODUCTION

There are no drugs approved by regulatory agencies for the treatment of nonalcoholic fatty liver disease (NAFLD); incretin combination therapies are being developed for treatment of type 2 diabetes and research has moved to test their usefulness in NAFLD.

AREAS COVERED

We reviewed the literature on the effectiveness of dual and triple peptides combining receptor agonists of the glucagon-like peptide 1, the glucose-dependent insulinotropic peptide, and glucagon to treat NAFLD and its associated metabolic diseases, and/or the cardiovascular risk intimately connected with the cluster of the metabolic syndrome. Other combination peptides involved the glucagon-like peptide 2 receptor, the fibroblast growth factor 21, the cholecystokinin receptor 2, and the amylin receptor.

EXPERT OPINION

Both dual and triple agonists are promising, based on animal, pharmacokinetic and proof-of concept studies, showing effectiveness both in the presence and the absence of diabetes on a few validated surrogate NAFLD biomarkers, but the majority of studies are still in progress. Considering the long natural history of NAFLD, final proof of their efficacy on primary clinical liver outcomes might be also derived from the analysis of large databases of National Healthcare Systems or Insurance companies, when used in diabetes for improving glycemic control, after careful propensity-score matching.

Dysglycemia Shapes Visceral Adipose Tissue's Response to GIP, GLP-1 and Glucagon in Individuals with Obesity

Visceral adipose tissue (VAT) metabolic fingerprints differ according to body mass index (BMI) and glycemic status. Glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP) and glucagon are gut-associated hormones that play an important role in regulating energy and glucose homeostasis, although their metabolic actions in VAT are still poorly characterized. Our aim was to assess whether GLP-1, GIP and glucagon influence the VAT metabolite profile. To achieve this goal, VAT harvested during elective surgical procedures from individuals (N = 19) with different BMIs and glycemic statuses was stimulated with GLP-1, GIP or glucagon, and culture media was analyzed using proton nuclear magnetic resonance. In the VAT of individuals with obesity and prediabetes, GLP-1 shifted its metabolic profile by increasing alanine and lactate production while also decreasing isoleucine consumption, whereas GIP and glucagon decreased lactate and alanine production and increased pyruvate consumption. In summary, GLP-1, GIP and glucagon were shown to distinctively modulate the VAT metabolic profile depending on the subject's BMI and glycemic status. In VAT from patients with obesity and prediabetes, these hormones induced metabolic shifts toward gluconeogenesis suppression and oxidative phosphorylation enhancement, suggesting an overall improvement in AT mitochondrial function.

Phase I studies of the safety, tolerability, pharmacokinetics and pharmacodynamics of the dual glucagon receptor/glucagon-like peptide-1 receptor agonist BI 456906

AIM

To report two phase I studies of the novel subcutaneous glucagon-like peptide-1 receptor/glucagon receptor (GLP-1R/GCGR) dual agonist BI 456906 versus placebo in healthy volunteers and people with overweight/obesity.

MATERIALS AND METHODS

A phase Ia study (NCT03175211) investigated single rising doses (SRDs) of BI 456906 in 24 males with a body mass index (BMI) of 20-<30 kg/m² . A phase Ib study (NCT03591718) investigated multiple rising doses (MRDs) of BI 456906 (escalated over 6 [Part A] or 16 [Part B] weeks) in 125 adults with a BMI of 27-40 kg/m² .

RESULTS

In the SRD study (N = 24), mean body weight decreased with increasing BI 456906 dose. In the MRD study, the maximum decreases in placebo-corrected mean body weight were at week 6 (-5.79%, dosage schedule [DS] 1; Part A) and week 16 (-13.8%, DS7; Part B). BI 456906 reduced plasma amino acids and glucagon, indicating target engagement at GCGRs and GLP-1Rs. Drug-related adverse events (AEs) increased with BI 456906 dose. The most frequent drug-related AE with SRDs was decreased appetite (n = 9, 50.0%), and two subjects (8.3%) did not complete the trial because of AEs (nausea and vomiting). During MRD Part A (N = 80), 10 subjects (12.5%) discontinued BI 456906, most commonly because of a cardiac or vascular AE (n = 6, 7.5%); during Part B (N = 45), eight subjects (17.8%) discontinued BI 456906, mainly because of AEs (n = 6, 13.3%), most commonly gastrointestinal disorders.

CONCLUSIONS

BI 456906 produced a placebo-corrected body weight loss of 13.8% (week 16), highlighting its potential to promote clinically meaningful body weight loss in people with overweight/obesity.

Glucagon and energy expenditure; Revisiting amino acid metabolism and implications for weight loss therapy

Glucagon receptor (GCGR)-targeted multi-agonists are being developed for the treatment of obesity and metabolic disease. GCGR activity is utilised for its favourable weight loss and metabolic properties, including increased energy expenditure (EE) and hepatic lipid metabolism. GLP1R and GIPR activities are increasingly present in a multi-agonist strategy. Due to the compound effect of increased satiety, reduced food intake and increased energy expenditure, the striking weight loss effects of these multi-agonists has been demonstrated in pre-clinical models of obesity. The precise contribution and mechanism of GCGR activity to enhanced energy expenditure and weight loss in both rodents and humans is not fully understood. In this review, our understanding of glucagon-mediated EE is explored, and an amino acid-centric paradigm contributing to this phenomenon is presented. The current progress of GCGR-targeted multi-agonists in development is also highlighted with a focus on the implications of glucagon-stimulated hypoaminoacidemia.

Brown Adipose Tissue-A Translational Perspective

Brown adipose tissue (BAT) displays the unique capacity to generate heat through uncoupled oxidative phosphorylation that makes it a very attractive therapeutic target for cardiometabolic diseases. Here, we review BAT cellular metabolism, its regulation by the central nervous and endocrine systems and circulating metabolites, the plausible roles of this tissue in human thermoregulation, energy balance, and cardiometabolic disorders, and the current knowledge on its pharmacological stimulation in humans. The current definition and measurement of BAT in human studies relies almost exclusively on BAT glucose uptake from positron emission tomography with 18F-fluorodeoxiglucose, which can be dissociated from BAT thermogenic activity, as for example in insulin-resistant states. The most important energy substrate for BAT thermogenesis is its intracellular fatty acid content mobilized from sympathetic stimulation of intracellular triglyceride lipolysis. This lipolytic BAT response is intertwined with that of white adipose (WAT) and other metabolic tissues, and cannot be independently stimulated with the drugs tested thus far. BAT is an interesting and biologically plausible target that has yet to be fully and selectively activated to increase the body's thermogenic response and shift energy balance. The field of human BAT research is in need of methods able to directly, specifically, and reliably measure BAT thermogenic capacity while also tracking the related thermogenic responses in WAT and other tissues. Until this is achieved, uncertainty will remain about the role played by this fascinating tissue in human cardiometabolic diseases.

Glucagon in type 2 diabetes: Friend or foe?

Hyperglucagonemia is one of the 'ominous' eight factors underlying the pathogenesis of type 2 diabetes (T2D). Glucagon is a peptide hormone involved in maintaining glucose homoeostasis by increasing hepatic glucose output to counterbalance insulin action. Long neglected, the introduction of dual and triple agonists exploiting glucagon signalling pathways has rekindled the interest in this hormone beyond its classic effect on glycaemia. Glucagon can promote weight loss by regulating food intake, energy expenditure, and brown and white adipose tissue functions through mechanisms still to be fully elucidated, thus its role in T2D pathogenesis should be further investigated. Moreover, the role of glucagon in the development of T2D micro- and macro-vascular complications is elusive. Mounting evidence suggests its beneficial effect in non-alcoholic fatty liver disease, while few studies postulated its favourable role in peripheral neuropathy and retinopathy. Contrarily, glucagon receptor agonism might induce renal changes resembling diabetic nephropathy, and data concerning glucagon actions on the cardiovascular system are conflicting. This review aims to summarise the available findings on the role of glucagon in the pathogenesis of T2D and its complications. Further experimental and clinical data are warranted to better understand the implications of glucagon signalling modulation with new antidiabetic drugs.

The Effects of Dual GLP-1/Glucagon Receptor Agonists with Different Receptor Selectivity in Mouse Models of Obesity and Nonalcoholic Steatohepatitis

There is an unmet need for nonalcoholic steatohepatitis (NASH) therapeutics, considering the increase in global obesity. Dual GLP-1/glucagon (GCG) receptor agonists have shown beneficial effects in circumventing the pathophysiology linked to NASH. However, dual GLP-1/GCG receptor agonists as a treatment of metabolic diseases need delicate optimization to maximize metabolism effects. The impacts of increased relative GLP-1/GCG receptor activity in NASH settings must be addressed to unleash the full potential. In this study, we investigated the potential of OXM-104 and OXM-101, two dual GLP-1/GCG receptor agonists with different receptor selectivity in the setting of NASH, to establish the relative receptor activities leading to the best metabolic outcome efficacies to reduce the gap between surgery and pharmacological interventions. We developed dual GLP-1/GCG receptor agonists with selective agonism. Despite the improved metabolic effects of OXM-101, we explored a hyperglycemic risk attached to increased relative GCG receptor agonism. Thirty-eight days of treatment with a dual GLP-1/GCG receptor agonist, OXM-104, with increased GLP-1 receptor agonism in obese NASH mice was found to ameliorate the development of NASH by lowering body weight, improving liver and lipid profiles, reducing the levels of the fibrosis marker PRO-C4, and improving glucose control. Similarly, dual GLP-1/GCG receptor agonist OXM-101 with increased relative GCG receptor agonism ameliorated NASH by eliciting dramatic body weight reductions to OXM-104, reflected in the improvement of liver and lipid enzymes and reduced PRO-C4 levels. Optimizing dual GLP-1/GCG agonists with increased relative GCG receptor agonism can provide the setting for future agonists to treat obesity, type 2 diabetes, and NASH without having a hyperglycemic risk. SIGNIFICANT STATEMENT: There is an unmet need for nonalcoholic steatohepatitis (NASH) therapeutics, considering the increase in global obesity. Dual GLP-1/glucagon (GCG) receptor agonists have shown beneficial effects in circumventing the pathophysiology linked to NASH. Therefore, this study has examined OXM-104 and OXM-101, two dual GLP-1/GCG receptor agonists in the setting of NASH, to establish the relative receptor activities leading to the best metabolic outcome efficacies to reduce the gap between surgery and pharmacological interventions.

A reappraisal of the role of cyclic AMP in the physiological action of glucagon

Effects of the metabolic hormone glucagon can be physiological or supraphysiological, based on agonist concentration and the mediating cellular signal. The threshold concentration (TC) for activating the AC/cAMP signal pathway in liver is ≥ 100 pM. By contrast, mean plasma concentrations are around 20-45 pM, depending on the vascular bed. Accordingly, effects produced at TCs below 100 pM are physiological and mediated by cellular signal pathways other than AC/cAMP. Effects generated at concentrations above 100 pM are supraphysiological, often mediated by simultaneous activation of cAMP-independent and -dependent pathways. Physiological responses, and their established or implicated signal pathways, include stimulation of: glucose mobilization, fatty acid oxidation, and urea synthesis in liver (PLC/IP3/Ca²⁺/CaM); lipolysis in white and brown adipose tissue and oxygen consumption in brown adipose of the rat but not in humans (PLC/IP3/Ca²⁺/CaM); renal potassium and phosphate excretion in rodents and GFR in humans (signal undetermined); and glucose utilization in rat heart (PI3K/akt). Supraphysiological responses involve the AC/cAMP pathway and include: enhanced stimulation of glucose mobilization and stimulation of urea synthesis in liver; further stimulation of white and brown adipose lipolysis and thermogenesis in brown adipose tissue; stimulation of renal Cl^- transport; and increased rat heart contractility. The AC/cAMP pathway is likely recruited when plasma glucagon rises above 100 pM during periods of elevated metabolic stress and systemic glucose demand, such as in the early neonate or strenuously exercising adult. The current cAMP-centered model should therefore be reconsidered and replaced with one that places more emphasis on cAMP-independent pathways.

Obesity and diabetes: the final frontier

INTRODUCTION

Obesity is a key target in the treatment and prevention of diabetes and independently to reduce the burden of cardiovascular disease. We reviewed the options now available and anticipated to deal with obesity.

AREAS COVERED

We considered the epidemiology, genetics, and causation of obesity and the relationship to diabetes, and the dietary, pharmaceutical, and surgical management of the condition. The literature search covered both popular media via Google Search and the academic literature as indexed on PubMed with search terms including obesity, childhood obesity, adipocytes, insulin resistance, mechanisms of satiety, bariatric surgery, GLP-1 receptor agonists, and SGLT2 inhibitors.

EXPERT OPINION

Although bariatric surgery has been the primary approach to treating obese individuals, the emergence of agents impacting the brain satiety centers now promises effective, non-invasive treatment of obesity for individuals with and without diabetes. The GLP-1 receptor agonists have assumed the primary role in treating obesity with significant weight loss. Long-term results with semaglutide and tirzepatide are now approaching the success seen with bariatric surgery. Future agents combining the benefits of satiety control and thermogenesis to dissipate caloric excess are under investigation.

BI 456906: Discovery and preclinical pharmacology of a novel GCGR/GLP-1R dual agonist with robust anti-obesity efficacy

OBJECTIVE

Obesity and its associated comorbidities represent a global health challenge with a need for well-tolerated, effective, and mechanistically diverse pharmaceutical interventions. Oxyntomodulin is a gut peptide that activates the glucagon receptor (GCGR) and glucagon-like peptide-1 receptor (GLP-1R) and reduces bodyweight by increasing energy expenditure and reducing energy intake in humans. Here we describe the pharmacological profile of the novel glucagon receptor (GCGR)/GLP-1 receptor (GLP-1R) dual agonist BI 456906.

METHODS

BI 456906 was characterized using cell-based in vitro assays to determine functional agonism. In vivo pharmacological studies were performed using acute and subchronic dosing regimens to demonstrate target engagement for the GCGR and GLP-1R, and weight lowering efficacy.

RESULTS

BI 456906 is a potent, acylated peptide containing a C18 fatty acid as a half-life extending principle to support once-weekly dosing in humans. Pharmacological doses of BI 456906 provided greater bodyweight reductions in mice compared with maximally effective doses of the GLP-1R agonist semaglutide. BI 456906's superior efficacy is the consequence of increased energy expenditure and reduced food intake. Engagement of both receptors in vivo was demonstrated via glucose tolerance, food intake, and gastric emptying tests for the GLP-1R, and liver nicotinamide N-methyltransferase mRNA expression and circulating biomarkers (amino acids, fibroblast growth factor-21) for the GCGR. The dual activity of BI 456906 at the GLP-1R and GCGR was supported using GLP-1R knockout and transgenic reporter mice, and an ex vivo bioactivity assay.

CONCLUSIONS

BI 456906 is a potent GCGR/GLP-1R dual agonist with robust anti-obesity efficacy achieved by increasing energy expenditure and decreasing food intake.

LY3437943, a novel triple GIP, GLP-1, and glucagon receptor agonist in people with type 2 diabetes: a phase 1b, multicentre, double-blind, placebo-controlled, randomised, multiple-ascending dose trial

BACKGROUND

Treating hyperglycaemia and obesity in individuals with type 2 diabetes using multi-receptor agonists can improve short-term and long-term outcomes. LY3437943 is a single peptide with agonist activity for glucagon, glucose-dependent insulinotropic polypeptide (GIP), and glucagon-like peptide 1 (GLP-1) receptors that is currently in development for the treatment of type 2 diabetes and for the treatment of obesity and associated comorbidities. We investigated the safety, pharmacokinetics, and pharmacodynamics of multiple weekly doses of LY3437943 in people with type 2 diabetes in a 12-week study.

METHODS

In this phase 1b, proof-of-concept, double-blind, placebo-controlled, randomised, multiple-ascending dose trial, adults (aged 20-70 years) with type 2 diabetes for at least 3 months, a glycated haemoglobin A_1c (HbA_1c) value of 7·0-10·5%, body-mass index of 23-50 kg/m², and stable bodyweight (<5% change in previous 3 months) were recruited at four centres in the USA. Using an interactive web-response system, participants were randomly assigned to receive once-weekly subcutaneous injections of LY3437943, placebo, or dulaglutide 1·5 mg over a 12-week period. Five ascending dose cohorts were studied, with randomisation in each cohort such that a minimum of nine participants received LY3437943, three received placebo, and one received dulaglutide 1·5 mg within each cohort. The top doses in the two highest dose cohorts were attained via stepwise dose escalations. The primary outcome was to investigate the safety and tolerability of LY3437943, and characterising the pharmacodynamics and pharmacokinetics were secondary outcomes. Safety was analysed in all participants who received at least one dose of study drug, and pharmacodynamics and pharmacokinetics in all participants who received at least one dose of study drug and had evaluable data. This trial is registered at ClinicalTrials.gov, NCT04143802.

FINDINGS

Between Dec 18, 2019, and Dec 28, 2020, 210 people were screened, of whom 72 were enrolled, received at least one dose of study drug, and were included in safety analyses. 15 participants had placebo, five had dulaglutide 1·5 mg and, for LY3437943, nine had 0·5 mg, nine had 1·5 mg, 11 had 3 mg, 11 had 3/6 mg, and 12 had 3/6/9/12 mg. 29 participants discontinued the study prematurely. Treatment-emergent adverse events were reported by 33 (63%), three (60%), and eight (54%) participants who received LY3437943, dulaglutide 1·5 mg, and placebo, respectively, with gastrointestinal disorders being the most frequently reported treatment-emergent adverse events. The pharmacokinetics of LY3437943 were dose proportional and its half-life was approximately 6 days. At week 12, placebo-adjusted mean daily plasma glucose significantly decreased from baseline at the three highest dose LY3437943 groups (least-squares mean difference -2·8 mmol/L [90% CI -4·63 to -0·94] for 3 mg; -3·1 mmol/L [-4·91 to -1·22] for 3/6 mg; and -2·9 mmol/L [-4·70 to -1·01] for 3/6/9/12 mg). Placebo-adjusted sHbA_1c also decreased significantly in the three highest dose groups (-1·4% [90% CI -2·17 to -0·56] for 3 mg; -1·6% [-2·37 to -0·75] for 3/6 mg; and -1·2% [-2·05 to -0·45] for 3/6/9/12 mg). Placebo-adjusted bodyweight reduction with LY3437943 appeared to be dose dependent (up to -8·96 kg [90% CI -11·16 to -6·75] in the 3/6/9/12 mg group).

INTERPRETATION

In this early phase study, LY3437943 showed an acceptable safety profile, and its pharmacokinetics suggest suitability for once-weekly dosing. This finding, together with the pharmacodynamic findings of robust reductions in glucose and bodyweight, provides support for phase 2 development.

FUNDING

Eli Lilly and Company.

Hypoaminoacidemia underpins glucagon-mediated energy expenditure and weight loss

Glucagon analogs show promise as components of next-generation, multi-target, anti-obesity therapeutics. The biology of chronic glucagon treatment, in particular, its ability to induce energy expenditure and weight loss, remains poorly understood. Using a long-acting glucagon analog, G108, we demonstrate that glucagon-mediated body weight loss is intrinsically linked to the hypoaminoacidemia associated with its known amino acid catabolic action. Mechanistic studies reveal an energy-consuming response to low plasma amino acids in G108-treated mice, prevented by dietary amino acid supplementation and mimicked by a rationally designed low amino acid diet. Therefore, low plasma amino acids are a pre-requisite for G108-mediated energy expenditure and weight loss. However, preventing hypoaminoacidemia with additional dietary protein does not affect the ability of G108 to improve glycemia or hepatic steatosis in obese mice. These studies provide a mechanism for glucagon-mediated weight loss and confirm the hepatic glucagon receptor as an attractive molecular target for metabolic disease therapeutics.

The past, present, and future physiology and pharmacology of glucagon

The evolution of glucagon has seen the transition from an impurity in the preparation of insulin to the development of glucagon receptor agonists for use in type 1 diabetes. In type 2 diabetes, glucagon receptor antagonists have been explored to reduce glycemia thought to be induced by hyperglucagonemia. However, the catabolic actions of glucagon are currently being leveraged to target the rise in obesity that paralleled that of diabetes, bringing the pharmacology of glucagon full circle. During this evolution, the physiological importance of glucagon advanced beyond the control of hepatic glucose production, incorporating critical roles for glucagon to regulate both lipid and amino acid metabolism. Thus, it is unsurprising that the study of glucagon has left several paradoxes that make it difficult to distill this hormone down to a simplified action. Here, we describe the history of glucagon from the past to the present and suggest some direction to the future of this field.

The acute effect of glucagon on components of energy balance and glucose homoeostasis in adults without diabetes: a systematic review and meta-analysis

Objective

Using a systematic review and meta-analysis, we aimed to estimate the mean effect of acute glucagon administration on components of energy balance and glucose homoeostasis in adults without diabetes.

Methods

CENTRAL, CINAHL, Embase, MEDLINE, PubMed, and Scopus databases were searched from inception to May 2021. To be included, papers had to be a randomised, crossover, single- or double-blind study, measuring ad libitum meal energy intake, energy expenditure, subjective appetite, glucose, and/or insulin following acute administration of glucagon and an appropriate comparator in adults without diabetes. Risk of bias was assessed using the Revised Cochrane Risk of Bias Tool for Randomized trials with additional considerations for cross-over trials. Certainty of evidence was assessed using the GRADE approach. Random-effect meta-analyses were performed for outcomes with at least five studies. This study is registered on PROSPERO (CRD42021269623).

Results

In total, 13 papers (15 studies) were considered eligible: energy intake (5 studies, 77 participants); energy expenditure (5 studies, 59 participants); subjective appetite (3 studies, 39 participants); glucose (13 studies, 159 participants); insulin (12 studies, 147 participants). All studies had some concerns with regards to risk of bias. Mean intervention effect of acute glucagon administration on energy intake was small (standardised mean difference [SMD]: –0.19; 95% CI, –0.59 to 0.21; P = 0.345). Mean intervention effect of acute glucagon administration on energy expenditure (SMD: 0.72; 95% CI, 0.37–1.08; P < 0.001), glucose (SMD: 1.11; 95% CI, 0.60–1.62; P < 0.001), and insulin (SMD: 1.33; 95% CI, 0.88–1.77; P < 0.001) was moderate to large.

Conclusions

Acute glucagon administration produces substantial increases in energy expenditure, and in circulating insulin and glucose concentrations. However, the effect of acute glucagon administration on energy intake is unclear. Insufficient evidence was available to evaluate the acute effect of glucagon on subjective appetite.

LY3437943, a novel triple glucagon, GIP, and GLP-1 receptor agonist for glycemic control and weight loss: From discovery to clinical proof of concept

With an increasing prevalence of obesity, there is a need for new therapies to improve body weight management and metabolic health. Multireceptor agonists in development may provide approaches to fulfill this unmet medical need. LY3437943 is a novel triple agonist peptide at the glucagon receptor (GCGR), glucose-dependent insulinotropic polypeptide receptor (GIPR), and glucagon-like peptide-1 receptor (GLP-1R). In vitro, LY3437943 shows balanced GCGR and GLP-1R activity but more GIPR activity. In obese mice, administration of LY3437943 decreased body weight and improved glycemic control. Body weight loss was augmented by the addition of GCGR-mediated increases in energy expenditure to GIPR- and GLP-1R-driven calorie intake reduction. In a phase 1 single ascending dose study, LY3437943 showed a safety and tolerability profile similar to other incretins. Its pharmacokinetic profile supported once-weekly dosing, and a reduction in body weight persisted up to day 43 after a single dose. These findings warrant further clinical assessment of LY3437943.

Positive association of glucagon with bone turnover markers in type 2 diabetes: A cross-sectional study

AIMS

The osteo-metabolic changes in type 2 diabetes (T2D) patients are intricate and have not been fully revealed. It is not clear whether glucagon is entirely harmful in the pathogenesis of diabetes or a possible endocrine counter-regulation mechanism to reverse some abnormal bone metabolism. This study aimed to investigate the association between glucagon and bone turnover markers (BTMs) in T2D patients.

METHODS

A total of 3984 T2D participants were involved in a cross-sectional study in Shanghai, China. Serum glucagon was measured to elucidate its associations with intact N-terminal propeptide of type I collagen (P1NP), osteocalcin (OC), and β-C-terminal telopeptide (β-CTX). Glucagon was detected with a radioimmunoassay. Propeptide of type I collagen, OC, and β-CTX were detected using chemiluminescence. The diagnosis of T2D was based on American Diabetes Association criteria.

RESULTS

The concentration of glucagon was positively correlated with two BTMs [OC-β: 0.034, 95% CI: 0.004, 0.051, p = 0.024; CTX-β: 0.035, 95% CI: 0.004, 0.062, p = 0.024]. The result of P1NP was [P1NP-regression coefficient (β): 0.027, 95% CI: -0.003, 0.049, p = 0.083]. In the glucagon tertiles, P for trend of the BTMs is [P1NP: 0.031; OC: 0.038; CTX: 0.020], respectively.

CONCLUSIONS

Glucagon had a positive effect on bone metabolism. The concentrations of the three BTMs increased as glucagon concentrations rose. This implied that glucagon might speed up skeletal remodelling, accelerate osteogenesis, and promote the formation of mature bone tissue. At the same time, the osteoclastic process was also accelerated, providing raw materials for osteogenesis to preserve the dynamic balance. In view of the successful use of single-molecule as well as dual/triple agonists, it would be feasible to develop a preparation that would reduce osteoporosis in diabetic patients.

Both caffeine and Capsicum annuum fruit powder lower blood glucose levels and increase brown adipose tissue temperature in healthy adult males

Using a combination of respiratory gas exchange, infrared thermography, and blood glucose (BGL) analysis, we have investigated the impact of Capsicum annuum (C. annuum) fruit powder (475 mg) or caffeine (100 mg) on metabolic activity in a placebo controlled (lactose, 100 mg) double-blinded three-way cross-over-design experiment. Metabolic measurements were made on day 1 and day 7 of supplementation in eight adult male participants (22.2 ± 2 years of age, BMI 23 ± 2 kg/m², x̅ ± SD). Participants arrived fasted overnight and were fed a high carbohydrate meal (90 g glucose), raising BGL from fasting baseline (4.4 ± 0.3 mmol/L) to peak BGL (8.5 ± 0.3 mmol/L) 45 min after the meal. Participants consumed the supplement 45 min after the meal, and both caffeine and C. annuum fruit powder restored BGL (F _(8,178) = 2.2, p = 0.02) to near fasting levels within 15 min of supplementation compared to placebo (120 min). In parallel both supplements increased energy expenditure (F _{(2, 21)} = 175.6, p < 0.001) over the 120-min test period (caffeine = 50.74 ± 2 kcal/kg/min, C. annuum fruit = 50.95 ± 1 kcal/kg/min, placebo = 29.34 ± 1 kcal/kg/min). Both caffeine and C. annuum fruit powder increased supraclavicular fossa temperature (F _(2,42) = 32, p < 0.001) on both day 1 and day 7 of testing over the 120-min test period. No statistical difference in core temperature or reference point temperature, mean arterial pressure or heart rate was observed due to supplementation nor was any statistical difference seen between day 1 and day 7 of intervention. This is important for implementing dietary ingredients as potential metabolism increasing supplements. Together the results imply that through dietary supplements such as caffeine and C. annuum, mechanisms for increasing metabolism can be potentially targeted to improve metabolic homeostasis in people.

Next generation GLP-1/GIP/glucagon triple agonists normalize body weight in obese mice

Objective

Pharmacological strategies that engage multiple mechanisms-of-action have demonstrated synergistic benefits for metabolic disease in preclinical models. One approach, concurrent activation of the glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic peptide (GIP), and glucagon (Gcg) receptors (i.e. triagonism), combines the anorectic and insulinotropic activities of GLP-1 and GIP with the energy expenditure effect of glucagon. While the efficacy of triagonism in preclinical models is known, the relative contribution of GcgR activation remains unassessed. This work aims to addresses that central question.

Methods

Herein, we detail the design of unimolecular peptide triagonists with an empirically optimized receptor potency ratio. These optimized peptide triagonists employ a protraction strategy permitting once-weekly human dosing. Additionally, we assess the effects of these peptides on weight-reduction, food intake, glucose control, and energy expenditure in an established DIO mouse model compared to clinically relevant GLP-1R agonists (e.g. semaglutide) and dual GLP-1R/GIPR agonists (e.g. tirzepatide).

Results

Optimized triagonists normalize body weight in DIO mice and enhance energy expenditure in a manner superior to that of GLP-1R mono-agonists and GLP-1R/GIPR co-agonists.

Conclusions

These pre-clinical data suggest unimolecular poly-pharmacology as an effective means to target multiple mechanisms contributing to obesity and further implicate GcgR activation as the differentiating factor between incretin receptor mono- or dual-agonists and triagonists.

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Details the design of unimolecular peptide triagonists for GLP-1R/GIPR/GCGR.

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Optimal weight-loss is achieved when receptor potency ratio is weighted toward GCGR vs GLP-1R or GIPR.

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These agonists are protracted for once-weekly human dosing.

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Optimized triagonists normalizes body weight & enhance energy expenditure in mice.

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Efficacy of optimized triagonists is superior to GLP-1R & GLP-1R/GIPR agonists.

A phase 1b randomised controlled trial of a glucagon-like peptide-1 and glucagon receptor dual agonist IBI362 (LY3305677) in Chinese patients with type 2 diabetes

The success of glucagon-like peptide-1 (GLP-1) receptor agonists to treat type 2 diabetes (T2D) and obesity has sparked considerable efforts to develop next-generation co-agonists that are more effective. We conducted a randomised, placebo-controlled phase 1b study (ClinicalTrials.gov: NCT04466904) to evaluate the safety and efficacy of IBI362 (LY3305677), a GLP-1 and glucagon receptor dual agonist, in Chinese patients with T2D. A total of 43 patients with T2D were enrolled in three cohorts in nine study centres in China and randomised in each cohort to receive once-weekly IBI362 (3.0 mg, 4.5 mg or 6.0 mg), placebo or open-label dulaglutide (1.5 mg) subcutaneously for 12 weeks. Forty-two patients received the study treatment and were included in the analysis, with eight receiving IBI362, four receiving placebo and two receiving dulaglutide in each cohort. The patients, investigators and study site personnel involved in treating and assessing patients in each cohort were masked to IBI362 and placebo allocation. Primary outcomes were safety and tolerability of IBI362. Secondary outcomes included the change in glycated haemoglobin A_1c (HbA_1c), fasting plasma glucose (FPG) and post-mixed-meal tolerance test (post-MTT) glucose levels. IBI362 was well tolerated. Most commonly-reported treatment-emergent adverse events were diarrhoea (29.2% for IBI362, 33.3% for dulaglutide, 0% for placebo), decreased appetite (25.0% for IBI362, 16.7% for dulaglutide, 0% for placebo) and nausea (16.7% for IBI362, 16.7% for dulaglutide and 8.3% for placebo). HbA_1c, FPG and post-MTT glucose levels were reduced from baseline to week 12 in patients receiving IBI362 in all three cohorts. IBI362 showed a favourable safety profile and clinically meaningful reductions in blood glucose in Chinese patients with T2D.

Glucagon-like peptide-1 receptor (GLP1R) agonists are used to treat type 2 diabetes (T2D), and polyagonists targeting multiple hormone receptors are investigated as potential therapeutics for T2D. Here the authors report that IBI362 (LY3305677), a balanced once-weekly GLP-1 and glucagon receptor dual agonist, showed favourable safety and tolerability in Chinese patients with type 2 diabetes in a randomized controlled phase 1b clinical trial.

Gut hormones and reproduction (Hormones intestinalis et reproduction)

Reproduction and metabolism are intricately linked. Gut hormones play key roles in the regulation of body weight and glucose homeostasis, factors that influence the functioning of the hypothalamic-pituitary-gonadal axis and reproductive outcomes. Data from rodent models suggest gut hormones may have direct stimulatory effects on reproductive hormone release. However, the effects of gut hormones on reproductive function in humans is more complex, with possible involvement of direct (e.g. via gut hormone receptor agonism) as well as indirect (e.g. via weight reduction in people with obesity) mechanisms. The use of gut hormone receptor agonists has become an integral part of the management of metabolic diseases (including obesity and type 2 diabetes), with additional indications for their use on the horizon. Future work may identify specific roles for gut hormones receptor agonists in the treatment of reproductive co-morbidities that are increasingly being recognised in people with metabolic diseases.

Managing weight and glycaemic targets in people with type 2 diabetes—How far have we come?

Introduction

As the vast majority of people with type 2 diabetes (T2D) are also overweight or obese, healthcare professionals (HCP) are faced with the task of addressing both weight management and glucose control. In this narrative review, we aim to identify the challenges of reaching and maintaining body weight targets in people with T2D and highlight current and future treatment interventions.

Methods

A search of the PubMed database was conducted using the search terms “diabetes” and “weight loss.”

Results

According to emerging evidence, treating obesity may be antecedent to the development and progression of T2D. While clinical benefits typically set in upon achieving a weight loss of 3–5%, these benefits are progressive leading to further health improvements, and weight loss of >15% can have a disease‐modifying effect in people with T2D, an outcome that up to recently could not be achieved with any blood glucose‐lowering pharmacotherapy. However, advanced treatment options with weight‐loss effects currently in development including the dual GIP/GLP‐1 receptor agonists may enable simultaneous achievement of individual glycemic and weight goals.

Conclusion

Despite considerable therapeutic progress, there is still a large unmet medical need in patients with T2D who miss their individualized glycemic and weight‐loss targets. Nonetheless, it is to be expected that development of future therapies and their use will favourably change the scenario of weight and glucose control in T2D.

Preclinical evaluation of a protracted GLP-1/glucagon receptor co-agonist: Translational difficulties and pitfalls

During recent years combining GLP-1 and glucagon receptor agonism with the purpose of achieving superior weight loss and metabolic control compared to GLP-1 alone has received much attention. The superior efficacy has been shown by several in preclinical models but has been difficult to reproduce in humans. In this paper, we present the pre-clinical evaluation of NN1177, a long-acting GLP-1/glucagon receptor co-agonist previously tested in clinical trials. To further investigate the contribution from the respective receptors, two other co-agonists (NN1151, NN1359) with different GLP-1-to-glucagon receptor ratios were evaluated in parallel. In the process of characterizing NN1177, species differences and pitfalls in traditional pre-clinical evaluation methods were identified, highlighting the translational challenges in predicting the optimal receptor balance in humans. In diet-induced obese (DIO) mice, NN1177 induced a dose-dependent body weight loss, primarily due to loss of fat mass, and improvement in glucose tolerance. In DIO rats, NN1177 induced a comparable total body weight reduction, which was in contrast mainly caused by loss of lean mass, and glucose tolerance was impaired. Furthermore, despite long half-lives of the three co-agonists, glucose control during steady state was seen to depend on compound exposure at time of evaluation. When evaluated at higher compound exposure, glucose tolerance was similarly improved for all three co-agonists, independent of receptor balance. However, at lower compound exposure, glucose tolerance was gradually impaired with higher glucagon receptor preference. In addition, glucose tolerance was found to depend on study duration where the effect of glucagon on glucose control became more evident with time. To conclude, the pharmacodynamic effects at a given GLP-1-to-glucagon ratio differs between species, depends on compound exposure and study length, complicating the identification of an optimally balanced clinical candidate. The present findings could partly explain the low number of clinical successes for this dual agonism.

Pancreatic alpha cells and glucagon secretion: Novel functions and targets in glucose homeostasis

Diabetes is the result of dysregulation of both insulin and glucagon. Still, insulin has attracted much more attention than glucagon. Glucagon is released from alpha cells in the islets of Langerhans in response to low glucose and certain amino acids. Drugs with the primary aim of targeting glucagon signalling are scarce. However, glucagon is often administered to counteract severe hypoglycaemia, and commonly used diabetes medications such as GLP-1 analogues, sulfonylureas and SGLT2-inhibitors also affect alpha cells. Indeed, there are physiological and developmental similarities between the alpha cell and the insulin-secreting beta cell and new data confirm that alpha cells can be converted into insulin-secreting cells. These aspects and attributes, the need to find novel therapies targeting the alpha cell and more are considered in this review.

The incretin/glucagon system as a target for pharmacotherapy of obesity

Obesity is a chronic, multifactorial, relapsing disease. Despite multicomponent lifestyle interventions, including pharmacotherapy, maintaining bodyweight loss is challenging for many people. The pathophysiology of obesity is complex, and currently approved pharmacotherapies only target a few of the many pathways involved; thus, single-targeting agents have limited efficacy. Proglucagon-derived peptides, glucagon, and the incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), represent attractive targets for managing obesity and metabolic disorders because they may have direct roles in multiple mechanisms including satiety, energy homeostasis, and lipolytic activity. Unimolecular dual and triple agonists targeting glucagon and incretin hormone receptors have been shown to promote bodyweight loss, lower glucose levels, and reduce food intake in animal models of obesity. Multiple dual receptor agonists are in clinical development for the treatment of obesity, including GLP-1/GIP and GLP-1/glucagon receptor agonists. The extent to which glucagon contributes to treatment effects remains to be understood, but it may promote bodyweight loss by reducing food intake, while concomitant GLP-1 receptor agonism ensures normal glucose control. Further research is required to fully understand the molecular mechanisms of action and metabolic effects of both dual and triple receptor agonists.

Is Glucagon Receptor Activation the Thermogenic Solution for Treating Obesity?

A major challenge of obesity therapy is to sustain clinically relevant weight loss over time. Achieving this goal likely requires both reducing daily caloric intake and increasing caloric expenditure. Over the past decade, advances in pharmaceutical engineering of ligands targeting G protein-coupled receptors have led to the development of highly effective anorectic agents. These include mono-agonists of the GLP-1R and dual GIPR/GLP-1R co-agonists that have demonstrated substantial weight loss in experimental models and in humans. By contrast, currently, there are no medicines available that effectively augment metabolic rate to promote weight loss. Here, we present evidence indicating that activation of the GCGR may provide a solution to this unmet therapeutic need. In adult humans, GCGR agonism increases energy expenditure to a magnitude sufficient for inducing a negative energy balance. In preclinical studies, the glucagon-GCGR system affects key metabolically relevant organs (including the liver and white and brown adipose tissue) to boost whole-body thermogenic capacity and protect from obesity. Further, activation of the GCGR has been shown to augment both the magnitude and duration of weight loss that is achieved by either selective GLP-1R or dual GIPR/GLP-1R agonism in rodents. Based on the accumulation of such findings, we propose that the thermogenic activity of GCGR agonism will also complement other anti-obesity agents that lower body weight by suppressing appetite.

The Efficacy of a Calamansi-Containing Energy Drink on Running Performance and Recovery in NCAA Division I Middle-Distance Runners: A Preliminary Study

This study examined the effects of a non-caffeinated energy drink (ED) that contained calamansi juice, glucose, and taurine on 3-km running performance and recovery. Eleven NCAA Division I middle-distance runners (20.8 ± 1.5 years old) were randomly assigned to consume either the ED or a placebo drink 60 min before 3-km running on a 400-m official track. Performance time and speed were recorded every 500-m interval. Recovery blood lactate concentration (BLC), systolic (SBP), diastolic blood pressure (DBP), and heart rate (HR) were measured at baseline, 60-min after ingesting the drinks, and post-running measurements were performed at 1-min, 5-min, and 10-min. Repeated analysis of variance and paired t-test were applied to examine the effects of time, trials, and their interaction on performance and recovery. Statistical significance was set a priori at p < 0.05. No significant difference was observed in performance time and speed between trials (p < 0.05). No interaction effect was found on performance time, speed, recovery BLC, DBP, and HR (p < 0.05). However, an interaction effect for trial by time was observed on SBP (p = 0.01). Recovery SBP continues to decrease from 5-min to 10-min in the ED trial (∆ = -13.9 mmHg) and slightly increased in the placebo trial (∆ = 1.1 mmHg). This study suggests that acute consumption of a calamansi-containing ED can positively impact the SBP recovery but not running performance. Further studies are needed to examine the acute and chronic effects of this ED on exercise performance and recovery among different populations.

GLP-1 physiology informs the pharmacotherapy of obesity

BACKGROUND

Glucagon-like peptide-1 receptor agonists (GLP1RA) augment glucose-dependent insulin release and reduce glucagon secretion and gastric emptying, enabling their successful development for the treatment of type 2 diabetes (T2D). These agents also inhibit food intake and reduce body weight, fostering investigation of GLP1RA for the treatment of obesity.

SCOPE OF REVIEW

Here I discuss the physiology of Glucagon-like peptide-1 (GLP-1) action in the control of food intake in animals and humans, highlighting the importance of gut vs. brain-derived GLP-1 for the control of feeding and body weight. The widespread distribution and function of multiple GLP-1 receptor (GLP1R) populations in the central and autonomic nervous system are outlined, and the importance of pathways controlling energy expenditure in preclinical studies vs. reduction of food intake in both animals and humans is highlighted. The relative contributions of vagal afferent pathways vs. GLP1R+ populations in the central nervous system for the physiological reduction of food intake and the anorectic response to GLP1RA are compared and reviewed. Key data enabling the development of two GLP1RA for obesity therapy (liraglutide 3 mg daily and semaglutide 2.4 mg once weekly) are discussed. Finally, emerging data potentially supporting the combination of GLP-1 with additional peptide epitopes in unimolecular multi-agonists, as well as in fixed-dose combination therapies, are highlighted.

MAJOR CONCLUSIONS

The actions of GLP-1 to reduce food intake and body weight are highly conserved in obese animals and humans, in both adolescents and adults. The well-defined mechanisms of GLP-1 action through a single G protein-coupled receptor, together with the extensive safety database of GLP1RA in people with T2D, provide reassurance surrounding the long-term use of these agents in people with obesity and multiple co-morbidities. GLP1RA may also be effective in conditions associated with obesity, such as cardiovascular disease and non-alcoholic steatohepatitis (NASH). Progressive improvements in the efficacy of GLP1RA suggest that GLP-1-based therapies may soon rival bariatric surgery as viable options for the treatment of obesity and its complications.