Glucagon-like peptide-1 receptor co-agonists for treating metabolic disease

Immunomodulation and inflammation: Role of GLP-1R and GIPR expressing cells within the gut

Glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are peptide hormones produced by enteroendocrine cells in the small intestine. Despite being produced in the gut, the leveraging of their role in potentiating glucose-stimulated insulin secretion, also known as the incretin effect, has distracted from discernment of direct intestinal signaling circuits. Both preclinical and clinical evidence have highlighted a role for the incretins in inflammation. In this review, we highlight the discoveries of GLP-1 receptor (GLP-1R)+ natural (TCRαβ and TCRγδ) and induced (TCRαβ+CD4+ cells and TCRαβ+CD8αβ+) intraepithelial lymphocytes. Both endogenous signaling and pharmacological activation of GLP-1R impact local and systemic inflammation, the gut microbiota, whole-body metabolism, as well as the control of GLP-1 bioavailability. While GIPR signaling has been documented to impact hematopoiesis, the impact of these bone marrow-derived cells in gut immunology is not well understood. We uncover gaps in the literature of the evaluation of the impact of sex in these GLP-1R and GIP receptor (GIPR) signaling circuits and provide speculations of the maintenance roles these hormones play within the gut in the fasting-refeeding cycles. GLP-1R agonists and GLP-1R/GIPR agonists are widely used as treatments for diabetes and weight loss, respectively; however, their impact on gut homeostasis has not been fully explored. Advancing our understanding of the roles of GLP-1R and GIPR signaling within the gut at homeostasis as well as metabolic and inflammatory diseases may provide targets to improve disease management.

Role of lifestyle and glucagon-like peptide-1 receptor agonists for weight loss in obesity, type 2 diabetes and steatotic liver diseases

BACKGROUND

The current obesity pandemic has given rise to associated comorbidities and complications, including type 2 diabetes and metabolic dysfunction-associated steatotic liver disease (MASLD). During the last decade, certain glucagon-like peptide 1 receptor agonists (GLP-1RA), originally developed as antihyperglycemic drugs, also demonstrated efficacy for weight loss.

AIMS

To review shared pathophysiologic features of common metabolic diseases and compare therapeutic strategies to reduce body weight and related complications.

METHODS

We performed an extensive literature research to describe the effects of lifestyle modification, first-generation anti-obesity drugs, and GLP-1RA on weight loss in humans with obesity, type 2 diabetes and MASLD.

RESULTS

Until recently, treatment of obesity has been limited to lifestyle modification, which offer moderate degree and sustainability of weight loss. The few approved first-generation anti-obesity drugs are either limited to short term use or to certain forms of obesity. Some GLP-1RA significantly decrease caloric intake and body weight. Liraglutide and semaglutide have therefore been approved for treating people with obesity. They also lead to a reduction of hepatic fat content and inflammation in people with biopsy-confirmed MASLD. Possible limitations comprise adverse effects, treatment adherence and persistence.

CONCLUSION

Certain GLP-1RA are superior to lifestyle modification and first-generation anti-obesity drugs in inducing weight loss. They have therefore markedly changed the portfolio of obesity treatment with additional beneficial effects on steatotic liver disease.

Machine learning designs new GCGR/GLP-1R dual agonists with enhanced biological potency

Several peptide dual agonists of the human glucagon receptor (GCGR) and the glucagon-like peptide-1 receptor (GLP-1R) are in development for the treatment of type 2 diabetes, obesity and their associated complications. Candidates must have high potency at both receptors, but it is unclear whether the limited experimental data available can be used to train models that accurately predict the activity at both receptors of new peptide variants. Here we use peptide sequence data labelled with in vitro potency at human GCGR and GLP-1R to train several models, including a deep multi-task neural-network model using multiple loss optimization. Model-guided sequence optimization was used to design three groups of peptide variants, with distinct ranges of predicted dual activity. We found that three of the model-designed sequences are potent dual agonists with superior biological activity. With our designs we were able to achieve up to sevenfold potency improvement at both receptors simultaneously compared to the best dual-agonist in the training set.

Customizable Click Biochemistry Strategy for the Design and Preparation of Glucagon-like Peptide-1 Conjugates and Coagonists

The development of oligomeric glucagon-like peptide-1 (GLP-1) and GLP-1-containing coagonists holds promise for enhancing the therapeutic potential of the GLP-1-based drugs for treating type 2 diabetes mellitus (T2DM). Here, we report a facile, efficient, and customizable strategy based on genetically encoded SpyCatcher-SpyTag chemistry and an inducible, cleavable self-aggregating tag (icSAT) scheme. icSAT-tagged SpyTag-fused GLP-1 and the dimeric or trimeric SpyCatcher scaffold were designed for dimeric or trimeric GLP-1, while icSAT-tagged SpyCatcher-fused GLP-1 and the icSAT-tagged SpyTag-fused GIP were designed for dual GLP-1/GIP (glucose-dependent insulinotropic polypeptide) receptor agonist. These SpyCatcher- and SpyTag-fused protein pairs were spontaneously ligated directly from the cell lysates. The subsequent icSAT scheme, coupled with a two-step standard column purification, resulted in target proteins with authentic N-termini, with yields ranging from 35 to 65 mg/L and purities exceeding 99%. In vitro assays revealed 3.0- to 4.1-fold increased activities for dimeric and trimeric GLP-1 compared to mono-GLP-1. The dual GLP-1/GIP receptor agonist exhibited balanced activity toward the GLP-1 receptor or the GIP receptor. All the proteins exhibited 1.8- to 3.0-fold prolonged half-lives in human serum compared to mono-GLP-1 or GIP. This study provides a generally applicable click biochemistry strategy for developing oligomeric or dual peptide/protein-based drug candidates.

Dulaglutide restores endothelial progenitor cell levels in diabetic mice and mitigates high glucose-induced endothelial injury through SIRT1-mediated mitochondrial fission

Type 2 diabetes mellitus (T2DM) significantly impairs the functionality and number of endothelial progenitor cells (EPCs) and resident endothelial cells, critical for vascular repair and regeneration, exacerbating the risk of vascular complications. GLP-1 receptor agonists, like dulaglutide, have emerged as promising therapeutic agents due to their multifaceted effects, including the enhancement of EPC activity and protection of endothelial cells. This study investigates dulaglutide's effects on peripheral blood levels of CD34+ and CD133+ cells in a mouse model of lower limb ischemia and its protective mechanisms against high-glucose-induced damage in endothelial cells. Results demonstrated that dulaglutide significantly improves blood flow, reduces tissue damage and inflammation in ischemic limbs, and enhances glycemic control. Furthermore, dulaglutide alleviated high-glucose-induced endothelial cell damage, evident from improved tube formation, reduced reactive oxygen species accumulation, and restored endothelial junction integrity. Mechanistically, dulaglutide mitigated mitochondrial fission in endothelial cells under high-glucose conditions, partly through maintaining SIRT1 expression, which is crucial for mitochondrial dynamics. This study reveals the potential of dulaglutide as a therapeutic option for vascular complications in T2DM patients, highlighting its role in improving endothelial function and mitochondrial integrity.

Glucagon kinetics assessed by mathematical modelling during oral glucose administration in people spanning from normal glucose tolerance to type 2 diabetes

Background/Objectives

Glucagon is important in the maintenance of glucose homeostasis, with also effects on lipids. In this study, we aimed to apply a recently developed model of glucagon kinetics to determine the sensitivity of glucagon variations (especially, glucagon inhibition) to insulin levels ("alpha-cell insulin sensitivity"), during oral glucose administration.

Subjects/Methods

We studied 50 participants (spanning from normal glucose tolerance to type 2 diabetes) undergoing frequently sampled 5-hr oral glucose tolerance test (OGTT). The alpha-cell insulin sensitivity and the glucagon kinetics were assessed by a mathematical model that we developed previously.

Results

The alpha-cell insulin sensitivity parameter (named SGLUCA; "GLUCA": "glucagon") was remarkably variable among participants (CV=221%). SGLUCA was found inversely correlated with the mean glycemic values, as well as with 2-hr glycemia of the OGTT. When stratifying participants into two groups (normal glucose tolerance, NGT, N=28, and impaired glucose regulation/type 2 diabetes, IGR_T2D, N=22), we found that SGLUCA was lower in the latter (1.50 ± 0.50·10-2 vs. 0.26 ± 0.14·10-2 ng·L-1 GLUCA/pmol·L-1 INS, in NGT and IGR_T2D, respectively, p=0.009; "INS": "insulin").

Conclusions

The alpha-cell insulin sensitivity is highly variable among subjects, and it is different in groups at different glucose tolerance. This may be relevant for defining personalized treatment schemes, in terms of dietary prescriptions but also for treatments with glucagon-related agents.

G protein-coupled receptors (GPCRs): advances in structures, mechanisms, and drug discovery

G protein-coupled receptors (GPCRs), the largest family of human membrane proteins and an important class of drug targets, play a role in maintaining numerous physiological processes. Agonist or antagonist, orthosteric effects or allosteric effects, and biased signaling or balanced signaling, characterize the complexity of GPCR dynamic features. In this study, we first review the structural advancements, activation mechanisms, and functional diversity of GPCRs. We then focus on GPCR drug discovery by revealing the detailed drug-target interactions and the underlying mechanisms of orthosteric drugs approved by the US Food and Drug Administration in the past five years. Particularly, an up-to-date analysis is performed on available GPCR structures complexed with synthetic small-molecule allosteric modulators to elucidate key receptor-ligand interactions and allosteric mechanisms. Finally, we highlight how the widespread GPCR-druggable allosteric sites can guide structure- or mechanism-based drug design and propose prospects of designing bitopic ligands for the future therapeutic potential of targeting this receptor family.

DPP-4 inhibitors sitagliptin and PF-00734,200 mitigate dopaminergic neurodegeneration, neuroinflammation and behavioral impairment in the rat 6-OHDA model of Parkinson's disease

Epidemiological studies report an elevated risk of Parkinson's disease (PD) in patients with type 2 diabetes mellitus (T2DM) that is mitigated in those prescribed dipeptidyl peptidase 4 (DPP-4) inhibitors. With an objective to characterize clinically translatable doses of DPP-4 inhibitors (gliptins) in a well-characterized PD rodent model, sitagliptin, PF-00734,200 or vehicle were orally administered to rats initiated either 7-days before or 7-days after unilateral medial forebrain bundle 6-hydroxydopamine (6-OHDA) lesioning. Measures of dopaminergic cell viability, dopamine content, neuroinflammation and neurogenesis were evaluated thereafter in ipsi- and contralateral brain. Plasma and brain incretin and DPP-4 activity levels were quantified. Furthermore, brain incretin receptor levels were age-dependently evaluated in rodents, in 6-OHDA challenged animals and human subjects with/without PD. Cellular studies evaluated neurotrophic/neuroprotective actions of combined incretin administration. Pre-treatment with oral sitagliptin or PF-00734,200 reduced methamphetamine (meth)-induced rotation post-lesioning and dopaminergic degeneration in lesioned substantia nigra pars compacta (SNc) and striatum. Direct intracerebroventricular gliptin administration lacked neuroprotective actions, indicating that systemic incretin-mediated mechanisms underpin gliptin-induced favorable brain effects. Post-treatment with a threefold higher oral gliptin dose, likewise, mitigated meth-induced rotation, dopaminergic neurodegeneration and neuroinflammation, and augmented neurogenesis. These gliptin-induced actions associated with 70-80% plasma and 20-30% brain DPP-4 inhibition, and elevated plasma and brain incretin levels. Brain incretin receptor protein levels were age-dependently maintained in rodents, preserved in rats challenged with 6-OHDA, and in humans with PD. Combined GLP-1 and GIP receptor activation in neuronal cultures resulted in neurotrophic/neuroprotective actions superior to single agonists alone. In conclusion, these studies support further evaluation of the repurposing of clinically approved gliptins as a treatment strategy for PD.

Sitagliptin elevates plasma and CSF incretin levels following oral administration to nonhuman primates: relevance for neurodegenerative disorders

The endogenous incretins glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) possess neurotrophic, neuroprotective, and anti-neuroinflammatory actions. The dipeptidyl peptidase 4 (DPP-4) inhibitor sitagliptin reduces degradation of endogenous GLP-1 and GIP, and, thereby, extends the circulation of these protective peptides. The current nonhuman primate (NHP) study evaluates whether human translational sitagliptin doses can elevate systemic and central nervous system (CNS) levels of GLP-1/GIP in naive, non-lesioned NHPs, in line with our prior rodent studies that demonstrated sitagliptin efficacy in preclinical models of Parkinson's disease (PD). PD is an age-associated neurodegenerative disorder whose current treatment is inadequate. Repositioning of the well-tolerated and efficacious diabetes drug sitagliptin provides a rapid approach to add to the therapeutic armamentarium for PD. The pharmacokinetics and pharmacodynamics of 3 oral sitagliptin doses (5, 20, and 100 mg/kg), equivalent to the routine clinical dose, a tolerated higher clinical dose and a maximal dose in monkey, were evaluated. Peak plasma sitagliptin levels were aligned both with prior reports in humans administered equivalent doses and with those in rodents demonstrating reduction of PD associated neurodegeneration. Although CNS uptake of sitagliptin was low (cerebrospinal fluid (CSF)/plasma ratio 0.01), both plasma and CSF concentrations of GLP-1/GIP were elevated in line with efficacy in prior rodent PD studies. Additional cellular studies evaluating human SH-SY5Y and primary rat ventral mesencephalic cultures challenged with 6-hydroxydopamine, established cellular models of PD, demonstrated that joint treatment with GLP-1 + GIP mitigated cell death, particularly when combined with DPP-4 inhibition to maintain incretin levels. In conclusion, this study provides a supportive translational step towards the clinical evaluation of sitagliptin in PD and other neurodegenerative disorders for which aging, similarly, is the greatest risk factor.

Incretin hormones and pharmacomimetics rapidly inhibit AgRP neuron activity to suppress appetite

Analogs of the incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP) have become mainstays of obesity and diabetes management. However, both the physiologic role of incretin hormones in the control of appetite and the pharmacologic mechanisms by which incretin-mimetic drugs suppress caloric intake remain incompletely understood. Hunger-promoting AgRP-expressing neurons are an important hypothalamic population that regulates food intake. Therefore, we set out to determine how incretins analogs affect their activity in vivo. Using fiber photometry, we observed that both GIP receptor (GIPR) and GLP-1 receptor (GLP-1R) agonism acutely inhibit AgRP neuron activity in fasted mice and reduce the response of AgRP neurons to food. Moreover, optogenetic stimulation of AgRP neurons partially attenuated incretin-induced feeding suppression, suggesting that AgRP neuron inhibition is necessary for the full appetite-suppressing effects of incretin-based therapeutics. Finally, we found that GIP but not GLP-1 is necessary for nutrient-mediated AgRP neuron inhibition, representing a novel physiologic role for GIP in maintaining energy balance. Taken together, these findings reveal neural mechanisms underlying the efficacy of incretin-mimetic obesity therapies. Understanding these drugs' mechanisms of action is crucial for the development of next-generation obesity pharmacotherapies with an improved therapeutic profile.

Glucagon-like-peptide-1 receptor agonists and the management of type 2 diabetes-backwards and forwards

This editorial is stimulated by the article by Alqifari et al published in the World Journal of Diabetes (2024). Alqifari et al focus on practical advice for the clinical use of glucagon-like-peptide-1 (GLP-1) receptor agonists (GLP-1RAs) in the management of type 2 diabetes and this editorial provides complementary information. We initially give a brief historical perspective of the development of GLP-1RAs stimulated by recognition of the 'incretin effect', the substantially greater insulin increase to enteral when compared to euglycaemic intravenous glucose, and the identification of the incretin hormones, GIP and GLP-1. In addition to stimulating insulin, GLP-1 reduces postprandial glucose levels by slowing gastric emptying. GLP-1RAs were developed because native GLP-1 has a very short plasma half-life. The majority of current GLP-1RAs are administered by subcutaneous injection once a week. They are potent in glucose lowering without leading to hypoglycaemia, stimulate weight loss in obese individuals and lead to cardiovascular and renal protection. The landscape in relation to GLP-1RAs is broadening rapidly, with different formulations and their combination with other peptides to facilitate both glucose lowering and weight loss. There is a need for more information relating to the effects of GLP-1RAs to induce gastrointestinal symptoms and slow gastric emptying which is likely to allow their use to become more effective and personalised.

Integrated genetic and epigenetic analyses uncovered GLP1R association with metabolically healthy obesity

BACKGROUND

Both genetic and epigenetic variations of GLP1R influence the development and progression of obesity. However, the underlying mechanism remains elusive. This study aims to explore the mediation roles of obesity-related methylation sites in GLP1R gene variants-obesity association.

METHODS

A total of 300 Chinese adult participants were included in this study and classified into two groups: 180 metabolically healthy obesity (MHO) cases and 120 metabolically healthy normal-weight (MHNW) controls. Questionnaire investigation, physical measurement and laboratory examination were assessed in all participants. 18 single nucleotide polymorphisms (SNPs) and 31 CpG sites were selected for genotype and methylation assays. Causal inference test (CIT) was performed to evaluate the associations between GLP1R genetic variation, DNA methylation and MHO.

RESULTS

The study found that rs4714211 polymorphism of GLP1R gene was significantly associated with MHO. Additionally, methylation sites in the intronic region of GLP1R (GLP1R-68-CpG 7.8.9; GLP1R-68-CpG 12.13; GLP1R-68-CpG 17; GLP1R-68-CpG 21) were associated with MHO, and two of these methylation sites (GLP1R-68-CpG 7.8.9; GLP1R-68-CpG 17) partially mediated the association between genotypes and MHO.

CONCLUSIONS

Not only the gene polymorphism, but also the DNA methylation of GLP1R was associated with MHO. Epigenetic changes in the methylome may in part explain the relationship between genetic variants and MHO.

Impact of treatment with GLP-1RAs on suicide attempts in adults persons with type 2 diabetes: A retrospective comparative effectiveness study based on a global TriNetX health research database

OBJECTIVE

To assess the association between glucagon-like peptide-1 receptor agonists (GLP-1RA) treatment and the risk of suicide attempts in people with type 2 diabetes (T2D), with a focus on subgroups with and without a history of depression or suicide attempts.

METHODS

This retrospective cohort study utilized TriNetX, a federated network of real-world data. Using the Global Collaborative Network data, we collected electronic medical records from 113 health care organizations with 135 million patient records with 8 million with T2D, 83% from the United States. The four cohorts were identified based on age, medication, diagnosis, and presence of depression or suicide attempts. Analytic methods included measures of association and number of Instances, with propensity score matching employed to mitigate potential confounders. The primary outcome was the incidence of suicide attempts among people with T2D with GLP-1RA treatment in comparison with dipeptidyl peptidase-4 inhibitor (DPP-4i) treatment.

RESULTS

People with T2D treated with GLP-1RA consistently exhibited a lower risk of suicide attempts compared to those treated with DPP-4i. This was particularly significant in people with a history of depression or suicide attempts. The risk and odds ratios were significantly lower in the GLP-1RA-treated cohorts than in DPP-4i across all analyses.

CONCLUSION

As compared with DPP-4i, our analysis shows a protective effect associated with GLP-1RA treatment on the risk of suicide attempts among people with T2D. However, further research, particularly prospective and randomized studies, is necessary to confirm these observations and understand the underlying mechanisms.

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.

Cardiovascular and mortality outcomes with GLP-1 receptor agonists vs other glucose-lowering drugs in individuals with NAFLD and type 2 diabetes: a large population-based matched cohort study

AIMS/HYPOTHESIS

We aimed to determine whether the use of glucagon-like peptide-1 receptor agonists (GLP-1RA) in individuals with non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus decreases the risk of new-onset adverse cardiovascular events (CVEs) and mortality rate compared with other glucose-lowering drugs in a real setting at a population level.

METHODS

We conducted a population-based propensity-matched retrospective cohort study using TriNetX. The cohort comprised patients over 20 years old who were newly treated with glucose-lowering drugs between 1 January 2013 and 31 December 2021, and followed until 30 September 2022. New users of GLP-1RAs were matched based on age, demographics, comorbidities and medication use by using 1:1 propensity matching with other glucose-lowering drugs. The primary outcome was the new onset of adverse CVEs, including heart failure, composite incidence of major adverse cardiovascular events (MACE; defined as unstable angina, myocardial infarction, or coronary artery procedures or surgeries) and composite cerebrovascular events (defined as the first occurrence of stroke, transient ischaemic attack, cerebral infarction, carotid intervention or surgery), and the secondary outcome was all-cause mortality. Cox proportional hazards models were used to estimate HRs.

RESULTS

The study involved 2,835,398 patients with both NAFLD and type 2 diabetes. When compared with the sodium-glucose cotransporter 2 (SGLT2) inhibitors group, the GLP-1RAs group showed no evidence of a difference in terms of new-onset heart failure (HR 0.97; 95% CI 0.93, 1.01), MACE (HR 0.95; 95% CI 0.90, 1.01) and cerebrovascular events (HR 0.99; 95% CI 0.94, 1.03). Furthermore, the two groups had no evidence of a difference in mortality rate (HR 1.06; 95% CI 0.97, 1.15). Similar results were observed across sensitivity analyses. Compared with other second- or third-line glucose-lowering medications, the GLP-1RAs demonstrated a lower rate of adverse CVEs, including heart failure (HR 0.88; 95% CI 0.85, 0.92), MACE (HR 0.89; 95% CI 0.85, 0.94), cerebrovascular events (HR 0.93; 95% CI 0.89, 0.96) and all-cause mortality rate (HR 0.70; 95% CI 0.66, 0.75).

CONCLUSIONS/INTERPRETATION

In individuals with NAFLD and type 2 diabetes, GLP-1RAs are associated with lower incidences of adverse CVEs and all-cause mortality compared with metformin or other second- and third-line glucose-lowering medications. However, there was no significant difference in adverse CVEs or all-cause mortality when compared with those taking SGLT2 inhibitors.

Multiomics analysis revealed the mechanism of the anti-diabetic effect of Salecan

Salecan, a natural β-glucan compromising nine residues connected by β-(1 → 3)/α-(1 → 3) glycosidic bonds, is one of the newly approved food ingredients. Salecan has multiple health-improving effects, yet its mechanism against Type 2 diabetes mellitus (T2DM) remains poorly understood. In this study, the hypoglycemic effect and underlying mechanism of Salecan intervention on STZ-induced diabetic model mice were investigated. After 8 weeks of gavage, Salecan attenuated insulin resistance and repaired pancreatic β cells in a dose-dependent manner. In addition, Salecan supplement remodel the structure of the gut microbiota and altered the level of intestinal metabolites. Serum metabolites, especially unsaturated fatty acids, were also affected significantly. In addition, tight junction proteins in the colon and autophagy-related proteins in the pancreas were upregulated. Multiomics analysis indicated that Lactobacillus johnsonii, Muribaculaceae, and Lachnoclostridium were highly associated with fatty acid esters of hydroxy fatty acids (FAHFA) levels in the colon, accordingly enhancing arachidonic acid and linoleic acid in serum, and promoting GLP-1 release in the intestine and insulin secretion in the pancreas, thus relieving insulin resistance and exhibiting hypoglycemic effects. These findings provide a novel understanding of the anti-diabetic effect of Salecan in mice from a molecular perspective, paving the way for the wide use of Salecan.

GLP-1 receptor agonists: A novel pharmacotherapy for binge eating (Binge eating disorder and bulimia nervosa)? A systematic review

Objective

Systematically review evidence on using GLP-1RAs for reducing BEB in BED and BN.

Methods

Comprehensive literature search (PubMed and Google Scholar) conducted for studies evaluating GLP-1Ras for BEB. Extracted data on study characteristics, efficacy, and safety.

Results

Studies show that GLP-1RAs (liraglutide and dulaglutide) reduce BE frequency and comorbidities in addition to favorable psychiatric side effect profile compared to current options. However, large-scale, blinded placebo-controlled trials are lacking.

Conclusion

Early findings suggest promising effects of GLP-1RAs on BEB. However, rigorous clinical trials are needed to firmly establish efficacy, dosing, safety, and comparative effectiveness before considering GLP-1RAs a viable novel approach.

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.

Construction and Identification of a Breast Bioreactor for Human-Derived Hypoglycemic Protein Amylin

The mammary gland of mammals can generate numerous bioactive proteins. To express the human amylin protein in the mammary glands of domestic animals, we engineered a transgenic mammary gland bioreactor. For this study, we produced transgenic mice through prokaryotic microinjection. RT-PCR, qPCR, and Western blotting confirmed the presence of transgenes in the mice. The ELISA assay indicated an amylin yield of approximately 1.44 μg/mL in the mice milk. Further research revealed that consuming milk containing amylin resulted in a slight, but insignificant enhancement in food consumption, blood sugar equilibrium, and glucose tolerance. The influence of amylin-fortified milk on the abundance of fecal strains in mice was examined, and a significant difference in the quantity of strains needed for fatty acid synthesis and metabolism was discovered. The amylin protein gathered from humans is safe to consume, as no harmful effects were detected in the mice. Our study examined the production of human amylin using a new safety strategy that could potentially alleviate diabetic symptoms in the future through oral administration of milk containing amylin.

Central glucagon-like peptide 1 receptor activation inhibits Toll-like receptor agonist-induced inflammation

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) exert anti-inflammatory effects relevant to the chronic complications of type 2 diabetes. Although GLP-1RAs attenuate T cell-mediated gut and systemic inflammation directly through the gut intraepithelial lymphocyte GLP-1R, how GLP-1RAs inhibit systemic inflammation in the absence of widespread immune expression of the GLP-1R remains uncertain. Here, we show that GLP-1R activation attenuates the induction of plasma tumor necrosis factor alpha (TNF-α) by multiple Toll-like receptor agonists. These actions are not mediated by hematopoietic or endothelial GLP-1Rs but require central neuronal GLP-1Rs. In a cecal slurry model of polymicrobial sepsis, GLP-1RAs similarly require neuronal GLP-1Rs to attenuate detrimental responses associated with sepsis, including sickness, hypothermia, systemic inflammation, and lung injury. Mechanistically, GLP-1R activation leads to reduced TNF-α via α1-adrenergic, δ-opioid, and κ-opioid receptor signaling. These data extend emerging concepts of brain-immune networks and posit a new gut-brain GLP-1R axis for suppression of peripheral inflammation.

GLP-1/GLP-1RAs: New Options for the Drug Treatment of NAFLD

Non-alcoholic fatty liver disease (NAFLD) has recently emerged as a global public health concern. Currently, the cornerstone of NAFLD treatment is lifestyle modification and, if necessary, weight loss. However, compliance is a challenge, and this approach alone may not be sufficient to halt and treat the more serious disease development, so medication is urgently needed. Nevertheless, no medicines are approved to treat NAFLD. Glucagon-like peptide-1 (GLP-1) is an enteropeptide hormone that inhibits glucagon synthesis, promotes insulin secretion, and delays gastric emptying. GLP-1 has been found in recent studies to be beneficial for the management of NAFLD, and the marketed GLP-1 agonist drugs have different degrees of effectiveness for NAFLD while lowering blood glucose. In this article, we review GLP-1 and its physiological roles, the pathogenesis of NAFLD, the correlation between NAFLD and GLP-1 signaling, and potential strategies for GLP-1 treatment of NAFLD.

GLP1 Receptor Agonists-Effects beyond Obesity and Diabetes

Glucagon-like peptide-1 receptor agonists (GLP1RA) have been transformative for patients and clinicians in treating type-2 diabetes and obesity. Drugs of this class, the bioavailability of which is continuously improving, enable weight loss and control blood glucose with minimal unwanted side effects. Since adopting GLP1RA for treating metabolic diseases, animal and clinical studies have revealed their beneficial effects on several other pathologies, including cardiovascular diseases, neurodegeneration, kidney disease, and cancer. A notable commonality between these diseases is their association with older age. Clinical trials and preclinical data suggest that GLP1RA may improve outcomes in these aging-related diseases. Some of the benefits of GLP1RA may be indirect due to their effects on obesity and glucose metabolism. However, there is building evidence that GLP1RA may also act directly on multiple organs implicated in aging-related pathology. This review aims to compile the studies reporting the effects of GLP1RA on aging-related diseases and discuss potential underlying mechanisms.

Genome-Wide Association Study for Somatic Skeletal Traits in Duroc × (Landrace × Yorkshire) Pigs

The pig bone weight trait holds significant economic importance in southern China. To expedite the selection of the pig bone weight trait in pig breeding, we conducted molecular genetic research on these specific traits. These traits encompass the bone weight of the scapula (SW), front leg bone weight (including humerus and ulna) (FLBW), hind leg bone weight (including femur and tibia) (HLBW), and spine bone weight (SBW). Up until now, the genetic structure related to these traits has not been thoroughly explored, primarily due to challenges associated with obtaining the phenotype data. In this study, we utilized genome-wide association studies (GWAS) to discern single nucleotide polymorphisms (SNPs) and genes associated with four bone weight traits within a population comprising 571 Duroc × (Landrace × Yorkshire) hybrid pigs (DLY). In the analyses, we employed a mixed linear model, and for the correction of multiple tests, both the false discovery rate and Bonferroni methods were utilized. Following functional annotation, candidate genes were identified based on their proximity to the candidate sites and their association with the bone weight traits. This study represents the inaugural application of GWAS for the identification of SNPs associated with individual bone weight in DLY pigs. Our analysis unveiled 26 SNPs and identified 12 promising candidate genes (OPRM1, SLC44A5, WASHC4, NOPCHAP1, RHOT1, GLP1R, TGFB3, PLCB1, TLR4, KCNJ2, ABCA6, and ABCA9) associated with the four bone weight traits. Furthermore, our findings on the genetic mechanisms influencing pig bone weight offer valuable insights as a reference for the genetic enhancement of pig bone traits.

Benefits and risks of drug combination therapy for diabetes mellitus and its complications: a comprehensive review

Diabetes is a chronic metabolic disease, and its therapeutic goals focus on the effective management of blood glucose and various complications. Drug combination therapy has emerged as a comprehensive treatment approach for diabetes. An increasing number of studies have shown that, compared with monotherapy, combination therapy can bring significant clinical benefits while controlling blood glucose, weight, and blood pressure, as well as mitigating damage from certain complications and delaying their progression in diabetes, including both type 1 diabetes (T1D), type 2 diabetes (T2D) and related complications. This evidence provides strong support for the recommendation of combination therapy for diabetes and highlights the importance of combined treatment. In this review, we first provided a brief overview of the phenotype and pathogenesis of diabetes and discussed several conventional anti-diabetic medications currently used for the treatment of diabetes. We then reviewed several clinical trials and pre-clinical animal experiments on T1D, T2D, and their common complications to evaluate the efficacy and safety of different classes of drug combinations. In general, combination therapy plays a pivotal role in the management of diabetes. Integrating the effectiveness of multiple drugs enables more comprehensive and effective control of blood glucose without increasing the risk of hypoglycemia or other serious adverse events. However, specific treatment regimens should be tailored to individual patients and implemented under the guidance of healthcare professionals.

Novel GLP-1(28-36) amide-derived hybrid peptide A3 with weight loss and hypoglycemic activities

Glucagon-like peptide-1 (GLP-1) has gained much attention in the last decade for the treatment of type 2 diabetes. Accumulating evidence indicates that some metabolites of GLP-1 have biological activities that might contribute to the pleiotropic effects of GLP-1 independent of the GLP-1 receptor. The hypoglycemic and weight-reducing effects of the reported metabolites and modifications still need to be confirmed. In this study, we started from the C-terminal nonapeptide GLP-1(28-36) amide and developed a series of GLP-1(28-36) amide-derived hybrid peptides. Our findings of biological activity evaluation in INS-1 cells, streptozotocin-induced diabetic and diet-induced obesity mice confirmed a novel hybrid peptide, A3, and provided a new perspective in the development of new drugs from peptide metabolites.

Challenging Clinical Perspectives in Type 2 Diabetes with Tirzepatide, a First-in-Class Twincretin

Tirzepatide is a first-in-class GIP/GLP-1 receptor agonist ('twincretin')-a single molecule that acts as an agonist at both glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) receptors. In the SURPASS clinical trial program in type 2 diabetes mellitus (T2D), tirzepatide was associated with unprecedented reductions in HbA1c, clinically significant weight loss and other metabolic benefits, combined with low rates of hypoglycaemia across a wide range of patient characteristics. The safety and adverse event rate for tirzepatide appears comparable to that of GLP-1 receptor agonists. Although results from dedicated cardiovascular (CV) and kidney trials are currently not available, information to date suggests that tirzepatide may have CV and kidney benefits in people with T2D. Tirzepatide has been approved for the treatment of T2D in the USA, United Arab Emirates, European Union, Japan and Australia. Here, we review how tirzepatide will fit into the T2D treatment continuum. We also consider future directions with tirzepatide in T2D, including its potential for targeting cardio-renal-metabolic disease in T2D, and discuss how tirzepatide-and other co-agonists in development-may challenge current approaches for management of T2D.

Postmarket safety profile of suicide/self-injury for GLP-1 receptor agonist: a real-world pharmacovigilance analysis

BACKGROUND

Recent reports of individuals experiencing suicidal and/or self-injurious behaviors while using liraglutide and semaglutide have heightened the concerns regarding neuropsychiatric safety of Glucagon-like peptide-1 agonists (GLP-1RAs). As real-world evidence is very limited, we explored the association between GLP-1RA and suicide/self-injury by mining the FDA Adverse Event Reporting System (FAERS) database.

METHODS

The FAERS database was queried from 2005 Q2 to 2023 Q2. The Reporting Odds Ratio (ROR) and Empirical Bayes Geometric Mean (EBGM) were used to conduct the disproportionality analysis.

RESULTS

A total of 534 GLP-1RA-associated suicide/self-injury cases were reported in the FAERS during the study period. GLP-1RA did not cause a disproportionate increase in overall suicidal and self-injurious cases (ROR: 0.16, 95%CI 0.15-0.18, P < 0.001; EBGM05: 0.15). Stratified analyses found no safety signal of suicide/injury for GLP-1RA in both females and males. The ROR for suicide/self-injury with GLP-1RA was slightly elevated (ROR: 2.50, 95%CI 1.02-6.13, P = 0.05) in children, while the EBGM05 was < 2 in this population. No significant signal value was observed in other age groups. No over-reporting of suicide/self-injury was identified for GLP-1RA before or after the COVID-19 pandemic outbreak.

CONCLUSIONS

The cases of suicide or self-injury reported to FAERS do not indicate any overall safety signal attributable to GLP-1RA at this time. Subgroup analysis revealed a marginal elevation of ROR for suicide and self-injury with GLP-1RA in children, but no safety signal was detected by EBGM05 in this population. Further large-scale prospective investigations are still warranted to further confirm this finding.

The Novel Tetra-Specific Drug C-192, Conjugated Using UniStac, Alleviates Non-Alcoholic Steatohepatitis in an MCD Diet-Induced Mouse Model

Non-alcoholic steatohepatitis (NASH) is a complex disease resulting from chronic liver injury associated with obesity, type 2 diabetes, and inflammation. Recently, the importance of developing multi-target drugs as a strategy to address complex diseases such as NASH has been growing; however, their manufacturing processes remain time- and cost-intensive and inefficient. To overcome these limitations, we developed UniStac, a novel enzyme-mediated conjugation platform for multi-specific drug development. UniStac demonstrated high conjugation yields, optimal thermal stabilities, and robust biological activities. We designed a tetra-specific compound, C-192, targeting glucagon-like peptide 1 (GLP-1), glucagon (GCG), fibroblast growth factor 21 (FGF21), and interleukin-1 receptor antagonist (IL-1RA) simultaneously for the treatment of NASH using UniStac. The biological activity and treatment efficacy of C-192 were confirmed both in vitro and in vivo using a methionine-choline-deficient (MCD) diet-induced mouse model. C-192 exhibited profound therapeutic efficacies compared to conventional drugs, including liraglutide and dulaglutide. C-192 significantly improved alanine transaminase levels, triglyceride accumulation, and the non-alcoholic fatty liver disease activity score. In this study, we demonstrated the feasibility of UniStac in creating multi-specific drugs and confirmed the therapeutic potential of C-192, a drug that integrates multiple mechanisms into a single molecule for the treatment of NASH.

Nonalcoholic fatty liver disease: Current therapies and future perspectives in drug delivery

Nonalcoholic fatty liver disease (NAFLD) affects approximately 25% of the adult population worldwide. This pathology can progress into end-stage liver disease with life-threatening complications, and yet no pharmacologic therapy has been approved. NAFLD is commonly characterized by excessive fat accumulation in the liver and is in closely associated with insulin resistance and metabolic disorders, which suggests that NAFLD is the hepatic manifestation of metabolic syndrome. Regarding treatment options, the current validated strategy relies on lifestyle modifications (exercise and diet restrictions). Although there are no approved drug-based treatments, several clinical trials are ongoing. Novel targets are being discovered, and the repurposing of drugs that show promising effects in NAFLD is starting to gain more interest. The field of nanotechnology has been growing at an increasing rate, with new and more efficient drug delivery strategies being developed for NAFLD treatment. Nanocarriers can easily encapsulate drugs that need to be better protected from the organism to exert their effect or that need help at reaching their target, thereby helping achieve a better bioavailability. Drug delivery systems can also be designed to target the site of the disease, in this case, the liver. In this review, we focus on the current knowledge of NAFLD pathology, the targets being considered for clinical trials, and the current guidelines and ongoing clinical trials, with a specific focus on potential oral treatments for NAFLD using promising drug delivery strategies.

Tirzepatide: A promising treatment for obesity?

ABSTRACT

Obesity affects a large percentage of patients in the United States and is associated with increased mortality and higher healthcare costs. Newer guidelines recommend a minimum of 10% weight loss goal for patients with obesity, and medical management options fall short. Tirzepatide, the first available dual-incretin analog, is a novel treatment for type 2 diabetes that also can induce weight loss. This article discusses tirzepatide as a treatment for obesity.

Gastrointestinal adverse events of tirzepatide in the treatment of type 2 diabetes mellitus: A meta-analysis and trials sequential analysis

BACKGROUND

Tirzepatide (TZP) is a novel drug for type 2 diabetes mellitus (T2DM), but the gastrointestinal (GI) adverse events (AEs) is a limiting factor in clinical application. Therefore, this study systematically evaluated the GI AEs of TZP for T2DM.

METHODS

Clinical trials of TZP for T2DM were retrieved from eight databases published only from the establishment of the database to February 2023. Revman5.3 and TSA0.9.5.10 Beta were used for meta-analysis and trials sequential analysis (TSA).

RESULTS

Meta-analysis showed that compared with placebo, total GI AEs, nausea, decreased appetite, constipation and vomiting were significantly higher in all dose groups of TZP (P < .05), while abdominal pain and abdominal distension were comparable (P > .05). TSA showed that the differences in total GI AEs, nausea, decreased appetite and constipation were conclusive. Compared with insulin, nausea, diarrhea, vomiting and decreased appetite were significantly increased in all doses of TZP (P < .05), and dyspepsia was significantly increased with TZP 15 mg (P < .05). TSA showed that these differences were all conclusive. Compared with GLP-1 RA, decreased appetite was significantly higher with TZP 5 mg, total GI AEs, decreased appetite and diarrhea were significantly higher with TZP 10 mg (P < .05), while nausea, vomiting, dyspepsia and constipation were significantly different in all dose groups, abdominal pain were not significantly different (P < .05) and TSA showed no conclusive results in this group.

CONCLUSION

The GI AEs of TZP were significantly higher than those of placebo and insulin, but comparable to GLP-1 RA. Nausea, diarrhea and decreased appetite are very common GI AEs of TZP, and the incidence is positively correlated with dose. GI AEs of TZP decrease gradually over time, so long-term steady medication may be expected to reduce GI AEs.

GLP-1 Receptor Agonists and Related Mental Health Issues; Insights from a Range of Social Media Platforms Using a Mixed-Methods Approach

The emergence of glucagon-like peptide-1 receptor agonists (GLP-1 RAs; semaglutide and others) now promises effective, non-invasive treatment of obesity for individuals with and without diabetes. Social media platforms' users started promoting semaglutide/Ozempic as a weight-loss treatment, and the associated increase in demand has contributed to an ongoing worldwide shortage of the drug associated with levels of non-prescribed semaglutide intake. Furthermore, recent reports emphasized some GLP-1 RA-associated risks of triggering depression and suicidal thoughts. Consistent with the above, we aimed to assess the possible impact of GLP-1 RAs on mental health as being perceived and discussed in popular open platforms with the help of a mixed-methods approach. Reddit posts yielded 12,136 comments, YouTube videos 14,515, and TikTok videos 17,059, respectively. Out of these posts/entries, most represented matches related to sleep-related issues, including insomnia (n = 620 matches); anxiety (n = 353); depression (n = 204); and mental health issues in general (n = 165). After the initiation of GLP-1 RAs, losing weight was associated with either a marked improvement or, in some cases, a deterioration, in mood; increase/decrease in anxiety/insomnia; and better control of a range of addictive behaviors. The challenges of accessing these medications were a hot topic as well. To the best of our knowledge, this is the first study documenting if and how GLP-1 RAs are perceived as affecting mood, mental health, and behaviors. Establishing a clear cause-and-effect link between metabolic diseases, depression and medications is difficult because of their possible reciprocal relationship, shared underlying mechanisms and individual differences. Further research is needed to better understand the safety profile of these molecules and their putative impact on behavioral and non-behavioral addictions.

The expanding incretin universe: from basic biology to clinical translation

Incretin hormones, principally glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1(GLP-1), potentiate meal-stimulated insulin secretion through direct (GIP + GLP-1) and indirect (GLP-1) actions on islet β-cells. GIP and GLP-1 also regulate glucagon secretion, through direct and indirect pathways. The incretin hormone receptors (GIPR and GLP-1R) are widely distributed beyond the pancreas, principally in the brain, cardiovascular and immune systems, gut and kidney, consistent with a broad array of extrapancreatic incretin actions. Notably, the glucoregulatory and anorectic activities of GIP and GLP-1 have supported development of incretin-based therapies for the treatment of type 2 diabetes and obesity. Here we review evolving concepts of incretin action, focusing predominantly on GLP-1, from discovery, to clinical proof of concept, to therapeutic outcomes. We identify established vs uncertain mechanisms of action, highlighting biology conserved across species, while illuminating areas of active investigation and uncertainty that require additional clarification.

The future of incretins in the treatment of obesity and non-alcoholic fatty liver disease

In the last few decades, glucagon-like peptide-1 receptor (GLP-1R) agonists have changed current guidelines and improved outcomes for individuals with type 2 diabetes. However, the dual glucose-dependent insulinotropic polypeptide receptor (GIPR)/GLP-1R agonist, tirzepatide, has demonstrated superior efficacy regarding improvements in HbA1c and body weight in people with type 2 diabetes. This has led to increasing scientific interest in incretin hormones and incretin interactions, and several compounds based on dual- and multi-agonists are now being investigated for the treatment of metabolic diseases. Herein, we highlight the key scientific advances in utilising incretins for the treatment of obesity and, potentially, non-alcoholic fatty liver disease (NAFLD). The development of multi-agonists with multi-organ targets may alter the natural history of these diseases.

Liver fat as risk factor of hepatic and cardiometabolic diseases

Non-alcoholic fatty liver disease (NAFLD) is a disorder characterized by excessive accumulation of fat in the liver that can progress to liver inflammation (non-alcoholic steatohepatitis [NASH]), liver fibrosis, and cirrhosis. Although most efforts for drug development are focusing on the treatment of the latest stages of NAFLD, where significant fibrosis and NASH are present, findings from studies suggest that the amount of liver fat may be an important independent risk factor and/or predictor of development and progression of NAFLD and metabolic diseases. In this review, we first describe the current tools available for quantification of liver fat in humans and then present the clinical and pathophysiological evidence that link liver fat with NAFLD progression as well as with cardiometabolic diseases. Finally, we discuss current pharmacological and non-pharmacological approaches to reduce liver fat and present open questions that have to be addressed in future studies.

Combination of an ACLY inhibitor with a GLP-1R agonist exerts additive benefits on nonalcoholic steatohepatitis and hepatic fibrosis in mice

Increased liver de novo lipogenesis (DNL) is a hallmark of nonalcoholic steatohepatitis (NASH). A key enzyme controlling DNL upregulated in NASH is ATP citrate lyase (ACLY). In mice, inhibition of ACLY reduces liver steatosis, ballooning, and fibrosis and inhibits activation of hepatic stellate cells. Glucagon-like peptide-1 receptor (GLP-1R) agonists lower body mass, insulin resistance, and steatosis without improving fibrosis. Here, we find that combining an inhibitor of liver ACLY, bempedoic acid, and the GLP-1R agonist liraglutide reduces liver steatosis, hepatocellular ballooning, and hepatic fibrosis in a mouse model of NASH. Liver RNA analyses revealed additive downregulation of pathways that are predictive of NASH resolution, reductions in the expression of prognostically significant genes compared with clinical NASH samples, and a predicted gene signature profile that supports fibrosis resolution. These findings support further investigation of this combinatorial therapy to treat obesity, insulin resistance, hypercholesterolemia, steatohepatitis, and fibrosis in people with NASH.

Body weight lowering effect of glucose-dependent insulinotropic polypeptide and glucagon-like peptide receptor agonists is more efficient in RAMP1/3 KO than in WT mice

The glucose-dependent insulinotropic polypeptide (GIPR) and glucagon-like peptide (GLP-1R) receptor agonists are insulin secretagogues that have long been shown to improve glycemic control and dual agonists have demonstrated successful weight loss in the clinic. GIPR and GLP-1R populations are located in the dorsal vagal complex where receptor activity-modifying proteins (RAMPs) are also present. According to recent literature, RAMPs not only regulate the signaling of the calcitonin receptor, but also that of other class B G-protein coupled receptors, including members of the glucagon receptor family such as GLP-1R and GIPR. The aim of this study was to investigate whether the absence of RAMP1 and RAMP3 interferes with the action of GIPR and GLP-1R agonists on body weight maintenance and glucose control. To this end, WT and RAMP 1/3 KO mice were fed a 45% high fat diet for 22 weeks and were injected daily with GLP-1R agonist (2 nmol/kg/d; NN0113-2220), GIPR agonist (30 nmol/kg/d; NN0441-0329) or both for 3 weeks. While the mono-agonists exerted little to no body weight lowering and anorectic effects in WT or RAMP1/3 KO mice, but at the given doses, when both compounds were administered together, they synergistically reduced body weight, with a greater effect observed in KO mice. Finally, GLP-1R and GIP/GLP-1R agonist treatment led to improved glucose tolerance, but the absence of RAMPs resulted in an improvement of the HOMA-IR score. These data suggest that RAMPs may play a crucial role in modulating the pharmacological actions of GLP-1 and GIP receptors.

Association of Glucagon to Insulin Ratio and Metabolic Syndrome in Patients with Type 2 Diabetes

There is a growing interest in the role of glucagon in type 2 diabetes mellitus (T2DM). Glucagon and insulin regulate glucose and lipid metabolism. Metabolic syndrome is an important risk factor for cardiovascular disease in patients with T2DM. We investigated the association between glucagon to insulin ratio and metabolic syndrome in patients with T2DM. This is a cross-sectional study involving 317 people with type 2 diabetes. Glucagon and insulin levels were measured in a fasted state and 30 min after ingesting a standard mixed meal. The Criteria of the International Diabetes Federation defined metabolic syndrome. Two hundred nineteen (69%) of the subjects had metabolic syndrome. The fasting glucagon to insulin ratio was significantly lower in patients with metabolic syndrome (14.0 ± 9.7 vs. 17.3 ± 10.3, p < 0.05). The fasting glucagon to insulin ratio was significantly lowered as the number of metabolic syndrome components increased. In hierarchical logistic regression analysis, the fasting glucagon to insulin ratio significantly contributed to metabolic syndrome even after adjusting for other covariates. The fasting glucagon to insulin ratio is inversely associated with metabolic syndrome in patients with type 2 diabetes. This suggests that glucagon-targeted therapeutics may reduce cardiovascular risk by improving metabolic syndrome.

GIPR/GLP-1R dual agonist therapies for diabetes and weight loss-chemistry, physiology, and clinical applications

The incretin system is an essential metabolic axis that regulates postprandial metabolism. The two incretin peptides that enable this effect are the glucose-dependent insulinotropic polypeptide (GIP) and the glucagon-like peptide 1 (GLP-1), which have cognate receptors (GIPR and GLP-1R) on islet β cells as well as in other tissues. Pharmacologic engagement of the GLP-1R is a proven strategy for treating hyperglycemia in diabetes and reducing body weight. Tirzepatide is the first monomeric peptide with dual activity at both incretin receptors now available for clinical use, and in clinical trials it has shown unprecedented effects to reduce blood glucose and body weight. Here, we discuss the foundational science that led to the development of monomeric multi-incretin receptor agonists, culminating in the development of tirzepatide. We also look to the future of this field and comment on how the concept of multi-receptor agonists will continue to progress for the treatment of metabolic disease.

The Cardiovascular Effect of Tirzepatide: A Glucagon-Like Peptide-1 and Glucose-Dependent Insulinotropic Polypeptide Dual Agonist

Glucagon-like peptide-1 (GLP-1) receptor agonists have been used extensively in the clinic and have an established safety profile in cardiovascular disease settings. For the treatment of peptide-secreting enteroendocrine cells, most research has focused on developing peptide multi-agonists as most of these cells are multihormonal. Among the various peptides secreted by enteroendocrine cells, the combination of GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) is an attractive strategy for treating type 2 diabetes mellitus (T2DM) because both of these hormones have glucose-lowering actions. Tirzepatide, a synthetic peptide composed of 39 amino acids, functions as a dual receptor agonist of both the GIP and GLP-1 receptors. This unique mechanism of action has earned tirzepatide the nickname "twincretin." Tirzepatide's dual agonist activity may be the mechanism by which tirzepatide significantly reduces glycated hemoglobin levels and body weight in patients with T2DM as observed in phase 3 clinical trials. Besides its glucose-lowering and anti-obesity effects, tirzepatide has been reported to have potential cardiovascular benefits. In this review, we discuss the cardiovascular effects of tirzepatide based on the available preclinical and clinical data.

GPCR Promiscuity Reshapes Islet Physiology

The family of proglucagon peptides Includes glucagon and glucagon-like peptide 1 (GLP-1), two unique peptides derived from the same prohormone. Despite numerous similarities between the peptides, these have long been viewed as having opposing actions on metabolism. GLP-1 is described as a postprandial hormone that stimulates anabolic actions via insulin, while glucagon is viewed as a fasting hormone that drives catabolic actions to maintain euglycemia. Here, we revisit a classic article in Diabetes that first established that glucagon and GLP-1 have more in common than previously appreciated, including actions at the same receptor. Furthermore, we discuss how the impact of this observation has guided research decades later that has reshaped the view of how proglucagon hormones regulate metabolism.

Gut-derived peptide hormone receptor expression in the developing mouse hypothalamus

OBJECTIVE

In adult organisms, a number of receptors have been identified which modulate metabolic processes related to peptides derived from the intestinal tract. These receptors play significant roles in glucose homeostasis, food intake and energy balance. Here we assess these classical metabolic receptors and their expression as well as their potential role in early development of hypothalamic neuronal circuits.

METHODS

Chow-fed C57BL6/N female mice were mated and hypothalamic tissue was collected from offspring across postnatal development (postnatal day 7-21). Subsequent qPCR and Western Blot analyses were used to determine mRNA and protein changes in gut-derived peptide hormone receptors. Correlations to body weight, blood glucose and circulating leptin levels were analyzed.

RESULTS

We describe the gene expression and dynamic protein regulation of key gut-derived peptide hormone receptors in the early postnatal period of the mouse brain. Specifically, we show changes to Gastric inhibitory polypeptide receptor (GIPR), glucagon-like peptide 1 receptor (GLP1R), and cholecystokinin receptor 2 (CCK2R) in the developing hypothalamus. The changes to GIPR and InsR seem to be strongly negatively correlated with body weight.

CONCLUSIONS

This comprehensive analysis underscores the need to understand the roles of maternal-derived circulating gut hormones and their direct effect on offspring brain development.

A Phase 1 Multiple Dose Study of Tirzepatide in Chinese Patients with Type 2 Diabetes

INTRODUCTION

To investigate the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of tirzepatide in Chinese patients with type 2 diabetes (T2D).

METHODS

In this phase 1, double-blind, placebo-controlled, multiple dose study, patients were randomized into one of two cohorts to receive once-weekly subcutaneous tirzepatide or placebo. The initial tirzepatide dose in both cohorts was 2.5 mg, which was increased by 2.5 mg every 4 weeks to a maximum final dose of 10.0 mg at week 16 (Cohort 1) or 15.0 mg at week 24 (Cohort 2). The primary outcome was the safety and tolerability of tirzepatide.

RESULTS

Twenty-four patients were randomized (tirzepatide 2.5-10.0 mg: n = 10, tirzepatide 2.5-15.0 mg: n = 10, placebo: n = 4); 22 completed the study. The most frequently reported treatment-emergent adverse events (TEAEs) among patients receiving tirzepatide were diarrhea and decreased appetite; most TEAEs were mild and resolved spontaneously with no serious adverse events reported in the tirzepatide groups and one in the placebo group. The plasma concentration half-life of tirzepatide was approximately 5-6 days. Mean glycated hemoglobin (HbA1c) decreased over time from baseline in the 2.5-10.0 mg (- 2.4%) and 2.5-15.0 mg (- 1.6%) tirzepatide groups, at week 16 and week 24, respectively, but remained steady in patients receiving placebo. Body weight decreased from baseline by - 4.2 kg at week 16 in the tirzepatide 2.5-10.0 mg group and by - 6.7 kg at week 24 in the 2.5-15.0 mg group. Mean fasting plasma glucose levels fell from baseline by - 4.6 mmol/L in the tirzepatide 2.5-10.0 mg group at week 16 and by - 3.7 mmol/L at week 24 in the tirzepatide 2.5-15.0 mg group.

CONCLUSIONS

Tirzepatide was well tolerated in this population of Chinese patients with T2D. The safety, tolerability, PK, and PD profile of tirzepatide support once-weekly dosing in this population.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov: NCT04235959.

Potential role of tirzepatide towards Covid-19 infection in diabetic patients: a perspective approach

In Covid-19, variations in fasting blood glucose are considered a distinct risk element for a bad prognosis and outcome in Covid-19 patients. Tirazepatide (TZT), a dual glucagon-like peptide-1 (GLP-1)and glucose-dependent insulinotropic polypeptide (GIP) receptor agonist may be effective in managing Covid-19-induced hyperglycemia in diabetic and non-diabetic patients. The beneficial effect of TZT in T2DM and obesity is related to direct activation of GIP and GLP-1 receptors with subsequent improvement of insulin sensitivity and reduction of body weight. TZT improves endothelial dysfunction (ED) and associated inflammatory changes through modulation of glucose homeostasis, insulin sensitivity, and pro-inflammatory biomarkers release. TZT, through activation of the GLP-1 receptor, may produce beneficial effects against Covid-19 severity since GLP-1 receptor agonists (GLP-1RAs) have anti-inflammatory and pulmoprotective implications in Covid-19. Therefore, GLP-1RAs could effectively treat severely affected Covid-19 diabetic and non-diabetic patients. Notably, using GLP-1RAs in T2DM patients prevents glucose variability, a common finding in Covid-19 patients. Therefore, GLP-1RAs like TZT could be a therapeutic strategy in T2DM patients with Covid-19 to prevent glucose variability-induced complications. In Covid-19, the inflammatory signaling pathways are highly activated, resulting in hyperinflammation. GLP-1RAs reduce inflammatory biomarkers like IL-6, CRP, and ferritin in Covid-19 patients. Therefore, GLP-1RAs like TZ may be effective in Covid-19 patients by reducing the inflammatory burden. The anti-obesogenic effect of TZT may reduce Covid-19 severity by ameliorating body weight and adiposity. Furthermore, Covid-19 may induce substantial alterations in gut microbiota. GLP-1RA preserves gut microbiota and prevents intestinal dysbiosis. Herein, TZT, like other GLP-1RA, may attenuate Covid-19-induced gut microbiota alterations and, by this mechanism, may mitigate intestinal inflammation and systemic complications in Covid-19 patients with either T2DM or obesity. As opposed to that, glucose-dependent insulinotropic polypeptide (GIP) was reduced in obese and T2DM patients. However, activation of GIP-1R by TZT in T2DM patients improves glucose homeostasis. Thus, TZT, through activation of both GIP and GLP-1, may reduce obesity-mediated inflammation. In Covid-19, GIP response to the meal is impaired, leading to postprandial hyperglycemia and abnormal glucose homeostasis. Therefore, using TZT in severely affected Covid-19 patients may prevent the development of glucose variability and hyperglycemia-induced oxidative stress. Moreover, exaggerated inflammatory disorders in Covid-19 due to the release of pro-inflammatory cytokines like IL-1β, IL-6, and TNF-α may lead to systemic inflammation and cytokine storm development. Besides, GIP-1 inhibits expression of IL-1β, IL-6, MCP-1, chemokines and TNF-α. Therefore, using GIP-1RA like TZT may inhibit the onset of inflammatory disorders in severely affected Covid-19 patients. In conclusion, TZT, through activation of GLP-1 and GIP receptors, may prevent SARS-CoV-2-induced hyperinflammation and glucose variability in diabetic and non-diabetic patients.

Usage of Glucagon-Like Peptide-1 for Obesity in Children; Updated Review of Clinicaltrials.gov

Background

Obesity in both adults and children is a primary health concern that can lead to many complications at a young age, including insulin resistance, type 2 diabetes, and other diseases. Glucagon-like peptide-1 receptor agonists (GLP-1) are drugs utilized to treat diabetes, but they are also approved as an adjunct to a low-calorie diet to reduce body weight and to enhance the metabolic profile readings for diabetic and non-diabetic patients. However, their efficacy and safety in children have not been extensively examined.

Aim

To identify glucagon-like peptide-1 medications for obesity in pediatric participants (aged up to 17 years old).

Methods

Analysis of all clinical trials registered on ClinicalTrials.gov for obesity using GLP-1 as a treatment for children.

Results

As of January 26th, 2023, 10,828 clinical trials were found. The search included childhood obesity using GLP-1. The number of trials on the use of GLP-1 to treat childhood obesity is limited. The final number of analyzed trials was 19. GLP-1 has been shown to result in the effective management of body gain among children.

Conclusion

Exenatide, semaglutide, and liraglutide were the only GLP-1 medications used as the pharmacotherapy option. It has been studied in many circumstances eg, to treat children with severe obesity, PCOS, hypothalamic obesity, glucose tolerance, and as a complementary treatment alongside behavior-lifestyle change and surgery for obesity.

Prediction and verification of the active ingredients and potential targets of Erhuang Quzhi Granules on non-alcoholic fatty liver disease based on network pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Erhuang Quzhi Granules (EQG) is a compound composed of 13 traditional Chinese medicines developed by the First Affiliated Hospital of Shihezi University. In clinical practice, EQG has been applied to the treatment of hyperlipidemia and non-alcoholic fatty liver disease (NAFLD), and could significantly improve the serum biochemical indicators of NAFLD patients.

AIM OF THE STUDY

This study aims to explore the bioactive compounds, potential targets, and molecular mechanisms of EQG against NAFLD through network pharmacology, molecular docking, and experimental verification.

MATERIALS AND METHODS

The chemical components of EQG came from the literature and quality standard. Bioactive compounds were screened based on the absorption, distribution, metabolism, and excretion (ADME) feature, and their potential targets were predicted using the substructure-drug-target network-based inference (SDTNBI). The core targets and signaling pathways were obtained through the analysis of protein-protein interaction (PPI), gene ontology (GO) function, and Kyoto encyclopedia of genes and genomes (KEGG) pathway. The results were further confirmed by literature retrieval, molecular docking, and in vivo experiments.

RESULTS

The results of network pharmacology showed 12 active ingredients and 10 core targets for EQG in treating NAFLD. And EQG mainly regulates lipid and atherosclerosis-related pathways to improve NAFLD. The collected literature verified the regulatory effect of the active components of EQG on core targets TP53, PPARG, EGFR, HIF1A, PPARA, and MTOR. Molecular docking results showed that Aloe-Emodin (AE), Emodin, Physcion, and Rhein (RH) had stable binding structures with the core targets HSP90AA1. In vivo experiment showed that AE and RH reduced aspartate transaminase (AST), alanine aminotransferase (ALT), interleukin (IL)-1β, IL-6, IL18, and tumor necrosis factor α (TNF-α) in the serum or liver of NAFLD mice, improved liver lipid deposition and fibrosis, and inhibit gene expression of nuclear factor kappa B (NF-κB), NOD-like receptor thermal protein domain associated protein 3 (NLRP3), IL-1β, TNF-α and protein expression of HSP90, NF-κB and Cleaved caspase-1.

CONCLUSIONS

This study comprehensively revealed the biological compounds, potential targets, and molecular mechanisms of EQG in the treatment of NAFLD, providing a reference basis for the promotion of EQG in the clinic.

Therapeutic Activity of Green Tea Epigallocatechin-3-Gallate on Metabolic Diseases and Non-Alcoholic Fatty Liver Diseases: The Current Updates

Green tea polyphenols have numerous functions including antioxidation and modulation of various cellular proteins and are thus beneficial against metabolic diseases including obesity, type 2 diabetes, cardiovascular and non-alcoholic fatty liver diseases, and their comorbidities. Epigallocatechin-3-gallate (EGCG) is the most abundant polyphenol in green tea and is attributed to antioxidant and free radical scavenging activities, and the likelihood of targeting multiple metabolic pathways. It has been shown to exhibit anti-obesity, anti-inflammatory, anti-diabetic, anti-arteriosclerotic, and weight-reducing effects in humans. Worldwide, the incidences of metabolic diseases have been escalating across all age groups in modern society. Therefore, EGCG is being increasingly investigated to address the problems. This review presents the current updates on the effects of EGCG on metabolic diseases, and highlights evidence related to its safety. Collectively, this review brings more evidence for therapeutic application and further studies on EGCG and its derivatives to alleviate metabolic diseases and non-alcoholic fatty liver diseases.

Pharmacokinetic, toxicological, and clinical considerations for the treatment of type 2 diabetes in patients with liver disease: a comprehensive update

INTRODUCTION

Type 2 diabetes and liver disease, mainly metabolic-associated fatty liver disease (MAFLD) and more rarely cirrhosis, coexist in many patients. This duality has direct implications for the physician when choosing glucose-lowering agents, with classical concerns but also recent new hopes.

AREAS COVERED

This updated comprehensive review will consider the pharmacokinetics, the tolerance/safety profile, the benefit/risk balance in cirrhosis, the effects on MAFLD and the risk of hepatocellular carcinoma of old and new glucose-lowering compounds in patients with liver disease, with a special focus on glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter 2 inhibitors.

EXPERT OPINION

We are currently facing a new paradigm in the management of patients with diabetes and liver disease. From previous reluctance when using antidiabetic agents (except insulin) in diabetic patients with hepatic impairment because of safety concerns, the commercialization of novel glucose-lowering agents has changed the scene. These agents, which have a good safety profile, are associated with weight loss and pleiotropic effects. They have proven their efficacy in improving MAFLD. However, more specific studies are still needed to prove their efficacy in preventing the progression to fibrosis/cirrhosis and confirm this new opportunity for the management of patients with diabetes and liver disease.

Future therapies for obesity

Obesity is a chronic disease associated with increased morbidity and mortality. Bariatric surgery can lead to sustained long-term weight loss (WL) and improvement in multiple obesity-related complications, but it is not scalable at the population level. Over the past few years, gut hormone-based pharmacotherapies for obesity and type 2 diabetes mellitus (T2DM) have rapidly evolved, and combinations of glucagon-like peptide 1 (GLP1) with other gut hormones (glucose-dependent insulinotropic polypeptide (GIP), glucagon, and amylin) as dual or triple agonists are under investigation to enhance and complement the effects of GLP1 on WL and obesity-related complications. Tirzepatide, a dual agonist of GLP1 and GIP receptors, marks a new era in obesity pharmacotherapy in which a combination of gut hormones could approach the WL achieved with bariatric surgery. In this review, we discuss emerging obesity treatments with a focus on gut hormone combinations and the concept of a multimodal approach for obesity management.

Glucagon-like peptide 1 receptor agonists: cardiovascular benefits and mechanisms of action

Type 2 diabetes mellitus (T2DM) and obesity are metabolic disorders characterized by excess cardiovascular risk. Glucagon-like peptide 1 (GLP1) receptor (GLP1R) agonists reduce body weight, glycaemia, blood pressure, postprandial lipaemia and inflammation - actions that could contribute to the reduction of cardiovascular events. Cardiovascular outcome trials (CVOTs) have demonstrated that GLP1R agonists reduce the rates of major adverse cardiovascular events in patients with T2DM. Separate phase III CVOTs of GLP1R agonists are currently being conducted in people living with heart failure with preserved ejection fraction and in those with obesity. Mechanistically, GLP1R is expressed at low levels in the heart and vasculature, raising the possibility that GLP1 might have both direct and indirect actions on the cardiovascular system. In this Review, we summarize the data from CVOTs of GLP1R agonists in patients with T2DM and describe the actions of GLP1R agonists on the heart and blood vessels. We also assess the potential mechanisms that contribute to the reduction in major adverse cardiovascular events in individuals treated with GLP1R agonists and highlight the emerging cardiovascular biology of novel GLP1-based multi-agonists currently in development. Understanding how GLP1R signalling protects the heart and blood vessels will optimize the therapeutic use and development of next-generation GLP1-based therapies with improved cardiovascular safety.