Dual GIP and GLP-1 Receptor Agonist Tirzepatide Improves Beta-cell Function and Insulin Sensitivity in Type 2 Diabetes

Tirzepatide modulates the regulation of adipocyte nutrient metabolism through long-acting activation of the GIP receptor

Tirzepatide, a glucose-dependent insulinotropic polypeptide/glucagon-like peptide 1 receptor (GIPR/GLP-1R) agonist, has, in clinical trials, demonstrated greater reductions in glucose, body weight, and triglyceride levels compared with selective GLP-1R agonists in people with type 2 diabetes (T2D). However, cellular mechanisms by which GIPR agonism may contribute to these improved efficacy outcomes have not been fully defined. Using human adipocyte and mouse models, we investigated how long-acting GIPR agonists regulate fasted and fed adipocyte functions. In functional assays, GIPR agonism enhanced insulin signaling, augmented glucose uptake, and increased the conversion of glucose to glycerol in a cooperative manner with insulin; however, in the absence of insulin, GIPR agonists increased lipolysis. In diet-induced obese mice treated with a long-acting GIPR agonist, circulating triglyceride levels were reduced during oral lipid challenge, and lipoprotein-derived fatty acid uptake into adipose tissue was increased. Our findings support a model for long-acting GIPR agonists to modulate both fasted and fed adipose tissue function differentially by cooperating with insulin to augment glucose and lipid clearance in the fed state while enhancing lipid release when insulin levels are reduced in the fasted state.

Use of Tirzepatide in Adults with Type 2 Diabetes Mellitus: Scientific Evidence and Practical Aspects

Tirzepatide is a novel antidiabetic medication a single-molecule, agonist to the glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptors. It is approved in the USA and EU for the treatment of type 2 diabetes mellitus (T2DM) and obesity. Due to the potential novelty represented by incorporating tirzepatide to clinical practice, we aim to review practical aspects of tirzepatide use in T2DM and the supporting scientific evidence. A group of ten endocrinologists involved as investigators in the phase 3 SURPASS clinical trial program followed a nominal group technique, a qualitative research methodology designed as a semi-structured group discussion to reach a consensus on the selection of a set of practical aspects. The scientific evidence for tirzepatide has been reviewed with respect to a number of patients' clinical profiles and care goals. Information of interest related to adverse events, special warnings and precautions, and other considerations for tirzepatide use has been included. Finally, information provided to the patients has been summarized. The practical aspects reported herein may be helpful in guiding physicians in the use of tirzepatide and contribute to optimizing the management of T2DM.

Therapeutic implications for sphingolipid metabolism in metabolic dysfunction-associated steatohepatitis

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD), a leading cause of chronic liver disease, has increased worldwide along with the epidemics of obesity and related dysmetabolic conditions characterized by impaired glucose metabolism and insulin signaling, such as type 2 diabetes mellitus (T2D). MASLD can be defined as an excessive accumulation of lipid droplets in hepatocytes that occurs when the hepatic lipid metabolism is totally surpassed. This metabolic lipid inflexibility constitutes a central node in the pathogenesis of MASLD and is frequently linked to the overproduction of lipotoxic species, increased cellular stress, and mitochondrial dysfunction. A compelling body of evidence suggests that the accumulation of lipid species derived from sphingolipid metabolism, such as ceramides, contributes significantly to the structural and functional tissue damage observed in more severe grades of MASLD by triggering inflammatory and fibrogenic mechanisms. In this context, MASLD can further progress to metabolic dysfunction-associated steatohepatitis (MASH), which represents the advanced form of MASLD, and hepatic fibrosis. In this review, we discuss the role of sphingolipid species as drivers of MASH and the mechanisms involved in the disease. In addition, given the absence of approved therapies and the limited options for treating MASH, we discuss the feasibility of therapeutic strategies to protect against MASH and other severe manifestations by modulating sphingolipid metabolism.

Tirzepatide Improved Markers of Islet Cell Function and Insulin Sensitivity in People With T2D (SURPASS-2)

CONTEXT

In previous SURPASS studies tirzepatide reduced hemoglobin glycated A1c (HbA1c) and body weight and improved markers of insulin sensitivity and β-cell function to a greater extent than comparators.

OBJECTIVE

Explore changes in biomarkers of β-cell function and insulin sensitivity and in efficacy profiles in baseline biomarker quartile analyses with tirzepatide compared to semaglutide.

DESIGN

Post hoc analysis of SURPASS-2 phase 3 trial (participants randomly assigned to receive weekly subcutaneous tirzepatide or semaglutide for 40 weeks).

SETTING

Post hoc analysis of 128 sites in 8 countries.

PARTICIPANTS

A total of 1879 participants with type 2 diabetes.

INTERVENTIONS

Once-weekly tirzepatide (5, 10, 15 mg) or semaglutide 1 mg.

MAIN OUTCOMES MEASURES

Change in homeostatic model assessment indices for pancreatic β-cell function (HOMA2-B) and for insulin resistance (HOMA2-IR), fasting glucagon, fasting C-peptide, and fasting insulin.

RESULTS

At week 40, a greater increase in HOMA2-B was seen with tirzepatide (5, 10, 15 mg) doses (96.9-120.4%) than with semaglutide 1 mg (84.0%) (P < .05). There was a greater reduction in HOMA2-IR with all doses of tirzepatide (15.5%-24.0%) than with semaglutide 1 mg (5.1%) (P < .05). Tirzepatide 10 and 15 mg resulted in a significant reduction in both fasting C-peptide (5.2%-6.0%) and fasting glucagon (53.0%-55.3%) compared with an increase of C-peptide (3.3%) and a reduction of glucagon (47.7%) with semaglutide 1 mg (P < .05). HbA1c and body weight reductions were greater with all tirzepatide doses than semaglutide within each HOMA2-B and HOMA2-IR baseline quartile.

CONCLUSION

In this post hoc analysis, improvements in HbA1c and weight loss were consistent and significantly higher with tirzepatide, regardless of baseline β-cell function and insulin resistance, compared with semaglutide.

Tirzepatide for Metabolic Dysfunction-Associated Steatohepatitis with Liver Fibrosis

BACKGROUND

Metabolic dysfunction-associated steatohepatitis (MASH) is a progressive liver disease associated with liver-related complications and death. The efficacy and safety of tirzepatide, an agonist of the glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptors, in patients with MASH and moderate or severe fibrosis is unclear.

METHODS

We conducted a phase 2, dose-finding, multicenter, double-blind, randomized, placebo-controlled trial involving participants with biopsy-confirmed MASH and stage F2 or F3 (moderate or severe) fibrosis. Participants were randomly assigned to receive once-weekly subcutaneous tirzepatide (5 mg, 10 mg, or 15 mg) or placebo for 52 weeks. The primary end point was resolution of MASH without worsening of fibrosis at 52 weeks. A key secondary end point was an improvement (decrease) of at least one fibrosis stage without worsening of MASH.

RESULTS

Among 190 participants who had undergone randomization, 157 had liver-biopsy results at week 52 that could be evaluated, with missing values imputed under the assumption that they would follow the pattern of results in the placebo group. The percentage of participants who met the criteria for resolution of MASH without worsening of fibrosis was 10% in the placebo group, 44% in the 5-mg tirzepatide group (difference vs. placebo, 34 percentage points; 95% confidence interval [CI], 17 to 50), 56% in the 10-mg tirzepatide group (difference, 46 percentage points; 95% CI, 29 to 62), and 62% in the 15-mg tirzepatide group (difference, 53 percentage points; 95% CI, 37 to 69) (P<0.001 for all three comparisons). The percentage of participants who had an improvement of at least one fibrosis stage without worsening of MASH was 30% in the placebo group, 55% in the 5-mg tirzepatide group (difference vs. placebo, 25 percentage points; 95% CI, 5 to 46), 51% in the 10-mg tirzepatide group (difference, 22 percentage points; 95% CI, 1 to 42), and 51% in the 15-mg tirzepatide group (difference, 21 percentage points; 95% CI, 1 to 42). The most common adverse events in the tirzepatide groups were gastrointestinal events, and most were mild or moderate in severity.

CONCLUSIONS

In this phase 2 trial involving participants with MASH and moderate or severe fibrosis, treatment with tirzepatide for 52 weeks was more effective than placebo with respect to resolution of MASH without worsening of fibrosis. Larger and longer trials are needed to further assess the efficacy and safety of tirzepatide for the treatment of MASH. (Funded by Eli Lilly; SYNERGY-NASH ClinicalTrials.gov number, NCT04166773.).

Effects of Tirzepatide Versus Basal Insulins in People With Type 2 Diabetes and Different Baseline Glycemic Patterns: Post Hoc Analyses of the SURPASS-3 and SURPASS-4 Trials

OBJECTIVE

This post hoc analysis assessed change from baseline to week 52 in glycemic parameters for tirzepatide (5, 10, 15 mg) versus insulin degludec (SURPASS-3 trial) and glargine (SURPASS-4 trial) in people with type 2 diabetes and different baseline glycemic patterns, based on fasting serum glucose (FSG) and postprandial glucose (PPG) values.

RESEARCH DESIGN AND METHODS

Participant subgroups with low FSG/low PPG, low FSG/high PPG, high FSG/low PPG, and high FSG/high PPG were defined according to the median values of these measures.

RESULTS

All tirzepatide doses and basal insulins were associated with decreased HbA1c, FSG, and PPG values from baseline to week 52 in all subgroups (P < 0.05). Within each subgroup, HbA1c and PPG decreases were greater with tirzepatide than insulin (P < 0.05). FSG decreases were generally similar. There were no differential treatment effects by FSG/PPG subgroup.

CONCLUSIONS

In this post hoc analysis, tirzepatide was associated with superior glycemic control compared with insulin, irrespective of baseline glycemic pattern.

Glucagon-like Peptide-1 analogues and delipidation of coronary atheroma in statin-treated type 2 diabetic patients with coronary artery disease: The prespecified sub-analysis of the OPTIMAL randomized clinical trial

Background and aims

Randomized clinical trials have demonstrated the ability of glucagon-like peptide-1 analogues (GLP-1RAs) to reduce atherosclerotic cardiovascular disease events in patients with type 2 diabetes (T2D). How GLP-1RAs modulate diabetic atherosclerosis remains to be determined yet.

Methods

The OPTIMAL study was a prospective randomized controlled study to compare the efficacy of 48-week continuous glucose monitoring- and HbA1c-guided glycemic control on near infrared spectroscopty (NIRS)/intravascular ultrasound (IVUS)-derived plaque measures in 94 statin-treated patients with T2D (jRCT1052180152, UMIN000036721). Of these, 78 patients with evaluable serial NIRS/IVUS images were analyzed to compare plaque measures between those treated with (n = 16) and without GLP-1RAs (n = 72).

Results

All patients received a statin, and on-treatment LDL-C levels were similar between the groups (66.9 ± 11.6 vs. 68.1 ± 23.2 mg/dL, p = 0.84). Patients receiving GLP-1RAs demonstrated a greater reduction of HbA1c [-1.0 (-1.4 to -0.5) vs. -0.4 (-0.6 to -0.2)%, p = 0.02] and were less likely to demonstrate a glucose level >180 mg/dL [-7.5 (-14.9 to -0.1) vs. 1.1 (-2.0 - 4.2)%, p = 0.04], accompanied by a significant decrease in remnant cholesterol levels [-3.8 (-6.3 to -1.3) vs. -0.1 (-0.8 - 1.1)mg/dL, p = 0.008]. On NIRS/IVUS imaging analysis, the change in percent atheroma volume did not differ between the groups (-0.9 ± 0.25 vs. -0.2 ± 0.2%, p = 0.23). However, GLP-1RA treated patients demonstrated a greater frequency of maxLCBI4mm regression (85.6 ± 0.1 vs. 42.0 ± 0.6%, p = 0.01). Multivariate analysis demonstrated that the GLP-1RA use was independently associated with maxLCBI4mm regression (odds ratio = 4.41, 95%CI = 1.19-16.30, p = 0.02).

Conclusions

In statin-treated patients with T2D and CAD, GLP-1RAs produced favourable changes in lipidic plaque materials, consistent with its stabilization.

Pancreatic beta-cell mass and function and therapeutic implications of using antidiabetic medications in type 2 diabetes

Nowadays, the focus of diabetes treatment has switched from lowering the glucose level to preserving glycemic homeostasis and slowing the disease progression. The main pathophysiology of both type 1 diabetes and long-standing type 2 diabetes is pancreatic β-cell mass loss and dysfunction. According to recent research, human pancreatic β-cells possess the ability to proliferate in response to elevated insulin demands. It has been demonstrated that in insulin-resistant conditions in humans, such as obesity or pregnancy, the β-cell mass increases. This ability could be helpful in developing novel treatment approaches to restore a functional β-cell mass. Treatment strategies aimed at boosting β-cell function and mass may be a useful tool for managing diabetes mellitus and stopping its progression. This review outlines the processes of β-cell failure and detail the many β-cell abnormalities that manifest in people with diabetes mellitus. We also go over standard techniques for determining the mass and function of β-cells. Lastly, we provide the therapeutic implications of utilizing antidiabetic drugs in controlling the mass and function of pancreatic β-cells.

Renal effects of GLP-1 receptor agonists and tirzepatide in individuals with type 2 diabetes: seeds of a promising future

PURPOSE

Chronic kidney disease (CKD) is one of the most common complications of type 2 diabetes (T2D), and CKD-related disability and mortality are increasing despite the recent advances in diabetes management. The dual GIP/GLP-1 receptor agonist tirzepatide is among the furthest developed multi-agonists for diabetes care and has so far displayed promising nephroprotective effects. This review aims to summarize the evidence regarding the nephroprotective effects of glucagon-like peptide-1 receptor agonists (GLP-1RA) and tirzepatide and the putative mechanisms underlying the favorable renal profile of tirzepatide.

METHODS

A comprehensive literature search was performed from inception to July 31st 2023 to select research papers addressing the renal effects of GLP-1RA and tirzepatide.

RESULTS

The pathogenesis of CKD in patients with T2D likely involves many contributors besides hyperglycemia, such as hypertension, obesity, insulin resistance and glomerular atherosclerosis, exerting kidney damage through metabolic, fibrotic, inflammatory, and hemodynamic mechanisms. Tirzepatide displayed an unprecedented glucose and body weight lowering potential, presenting also with the ability to increase insulin sensitivity, reduce systolic blood pressure and inflammation and ameliorate dyslipidemia, particularly by reducing triglycerides levels.

CONCLUSION

Tirzepatide is likely to counteract most of the pathogenetic factors contributing to CKD in T2D, potentially representing a step forward in incretin-based therapy towards nephroprotection. Further evidence is needed to understand its role in renal hemodynamics, fibrosis, cell damage and atherosclerosis, as well as to conclusively show reduction of hard renal outcomes.

Tirzepatide: A novel cardiovascular protective agent in type 2 diabetes mellitus and obesity

Cardiovascular disease (CVD) remains a major global health concern, and obesity and diabetes mellitus have been found to be important risk factors. Tirzepatide a dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP1) receptor agonist has been shown to have cardioprotective effects. Noteworthy benefits of Tirzepatide include decreased cardiovascular risk factors in people with Type 2 diabetes mellitus (T2DM). In the SURPASS-4 trial, tirzepatide significant decreased blood pressure, body weight, and HbA1c. Furthermore, the SURMOUNT-1 trial demonstrated the effectiveness of tirzepatide in reducing cardiometabolic risk factors in people with obesity without T2DM. Together, the dual receptor agonism improves lipid profiles, increases insulin secretion, reduces inflammation, and promotes endothelial integrity. Tirzepatide shows promise as a comprehensive therapeutic option for managing cardiovascular risk factors in patients with T2DM and obesity. While further studies are needed to assess the long-term cardiovascular benefits, current evidence supports tirzepatide's potential impact on cardiovascular health beyond its antidiabetic properties.

Development of Syringaldehyde as an Agonist of the GLP-1 Receptor to Alleviate Diabetic Disorders in Animal Models

The phenolic aldehyde syringaldehyde (SA) has been shown to have an antihyperglycemic effect in diabetic rats due to increased glucose utilization and insulin sensitivity. To understand the direct effect of SA on the GLP-1 receptor, STZ-induced diabetic rats were used. The levels of pro-inflammatory cytokines, liver enzymes, and renal function were measured using specific ELISA kits. The mechanisms of SA effects were investigated using CHO-K1 cells, pancreatic Min-6 cells, and cardiomyocyte H9c2 cells. The results indicated that the antihyperglycemic effect of SA in diabetic rats was abolished by blocking the GLP-1 receptor with an antagonist. SA has a direct effect on the GLP-1 receptor when using CHO-K1 cells transfected with the exogenous GLP-1 receptor gene. In addition, SA stimulated insulin production in Min-6 cells by activating GLP-1 receptors. SA caused a dose-dependent rise in GLP-1 receptor mRNA levels in cardiac H9c2 cells. These in vitro results support the notion that SA has a direct effect on the GLP-1 receptor. Otherwise, SA inhibited the increase of pro-inflammatory cytokines, including interleukins and tumor TNF-α, in type 1 diabetic rats in a dose-dependent manner. Moreover, as with liraglutide, SA reduced plasma lipid profiles, including total cholesterol and triglyceride, in mixed diet-induced type 2 diabetic rats. Intriguingly, chronic treatment with SA (as with liraglutide) reversed the functions of both the liver and the kidney in these diabetic rats. SA displayed less efficiency in reducing body weight and food consumption compared to liraglutide. In conclusion, SA effectively activates GLP-1 receptors, resulting in a reduction in diabetic-related complications in rats. Therefore, it is beneficial to develop SA as a chemical agonist for clinical applications in the future.

Conjugated Linoleic Acid Ameliorates High Fat-Induced Insulin Resistance via Regulating Gut Microbiota-Host Metabolic and Immunomodulatory Interactions

Interaction between gut microbiota, host immunity and metabolism has been suggested to crucially affect the development of insulin resistance (IR). This study aims to investigate how gut microbiota, inflammatory responses and metabolism in individuals with IR are affected by the supplementation of conjugated linoleic acid (CLA) and how this subsequently affects the pathophysiology of IR by using a high-fat diet-induced IR mouse model. Serum biochemical indices showed that 400 mg/kg body weight of CLA effectively attenuated hyperglycemia, hyperlipidemia, glucose intolerance and IR, while also promoting antioxidant capacities. Histomorphology, gene and protein expression analysis revealed that CLA reduced fat deposition and inflammation, and enhanced fatty acid oxidation, insulin signaling and glucose transport in adipose tissue or liver. Hepatic transcriptome analysis confirmed that CLA inhibited inflammatory signaling pathways and promoted insulin, PI3K-Akt and AMPK signaling pathways, as well as linoleic acid, arachidonic acid, arginine and proline metabolism. Gut microbiome analysis further revealed that these effects were highly associated with the enriched bacteria that showed positive correlation with the production of short-chain fatty acids (SCFAs), as well as the improved SCFAs production simultaneously. This study highlights the therapeutic actions of CLA on ameliorating IR via regulating microbiota-host metabolic and immunomodulatory interactions, which have important implications for IR control.

Glucagon-like peptide-1 analogs: Miracle drugs are blooming?

Glucagon-like peptide-1 (GLP-1), secreted by L cells in the small intestine, assumes a central role in managing type 2 diabetes mellitus (T2DM) and obesity. Its influence on insulin secretion and gastric emptying positions it as a therapeutic linchpin. However, the limited applicability of native GLP-1 stems from its short half-life, primarily due to glomerular filtration and the inactivating effect of dipeptidyl peptidase-IV (DPP-IV). To address this, various structural modification strategies have been developed to extend GLP-1's half-life. Despite the commendable efficacy displayed by current GLP-1 receptor agonists, inherent limitations persist. A paradigm shift emerges with the advent of unimolecular multi-agonists, such as the recently introduced tirzepatide, wherein GLP-1 is ingeniously combined with other gastrointestinal hormones. This novel approach has captured the spotlight within the diabetes and obesity research community. This review summarizes the physiological functions of GLP-1, systematically explores diverse structural modifications, delves into the realm of unimolecular multi-agonists, and provides a nuanced portrayal of the developmental prospects that lie ahead for GLP-1 analogs.

Characterization of Plant-Derived Natural Inhibitors of Dipeptidyl Peptidase-4 as Potential Antidiabetic Agents: A Computational Study

Diabetes, characterized by elevated blood sugar levels, poses significant health and economic risks, correlating with complications like cardiovascular disease, kidney failure, and blindness. Dipeptidyl peptidase-4 (DPP-4), also referred to as T-cell activation antigen CD26 (EC 3.4.14.5.), plays a crucial role in glucose metabolism and immune function. Inhibiting DPP-4 was anticipated as a potential new therapy for diabetes. Therefore, identification of plant-based natural inhibitors of DPP-4 would help in eradicating diabetes worldwide. Here, for the identification of the potential natural inhibitors of DPP-4, we developed a phytochemicals library consisting of over 6000 phytochemicals detected in 81 medicinal plants that exhibited anti-diabetic potency. The library has been docked against the target proteins, where isorhamnetin, Benzyl 5-Amino-5-deoxy-2,3-O-isopropyl-alpha-D-mannofuranoside (DTXSID90724586), and 5-Oxo-7-[4-(trifluoromethyl) phenyl]-4H,6H,7H-[1,2]thiazolo[4,5-b]pyridine 3-carboxylic acid (CHEMBL3446108) showed binding affinities of -8.5, -8.3, and -8.3 kcal/mol, respectively. These compounds exhibiting strong interactions with DPP-4 active sites (Glu205, Glu206, Tyr547, Trp629, Ser630, Tyr662, His740) were identified. ADME/T and bioactivity predictions affirmed their pharmacological safety. Density functional theory calculations assessed stability and reactivity, while molecular dynamics simulations demonstrated persistent stability. Analyzing parameters like RMSD, RG, RMSF, SASA, H-bonds, MM-PBSA, and FEL confirmed stable protein-ligand compound formation. Principal component analysis provided structural variation insights. Our findings suggest that those compounds might be possible candidates for developing novel inhibitors targeting DPP-4 for treating diabetes.

Psychiatric adverse events associated with semaglutide, liraglutide and tirzepatide: a pharmacovigilance analysis of individual case safety reports submitted to the EudraVigilance database

BACKGROUND

Semaglutide, liraglutide and tirzepatide are glucagon-like peptide-1 (GLP-1) receptor agonists that are effective for weight reduction. Recent reports of patients experiencing suicidal thoughts and other psychiatric adverse events while using GLP-1 agonists have raised concerns about the potential risk of self-harm and led the European Medicines Agency to investigate these medications.

AIM

To identify and analyse the psychiatric adverse events associated with semaglutide, liraglutide and tirzepatide.

METHOD

All individual case safety reports for semaglutide, liraglutide, and tirzepatide reported to the EudraVigilance database from 01/01/2021 to 30/05/2023 were analysed. Descriptive statistics were used to explore study population characteristics.

RESULTS

During the study period, 31,444 adverse event reports were identified: semaglutide (n = 13,956; 44.4%), liraglutide (n = 16,748; 53.2%), and tirzepatide (n = 740; 2.3%). There were 372 reports with psychiatric adverse event reports (n = 372; 1.18%) with a total of 481 adverse events. Women accounted for 65% (n = 242) of these reports. Depression was the most commonly reported adverse event (n = 187; 50.3%), followed by anxiety (n = 144; 38.7%) and suicidal ideation (n = 73; 19.6%). Nine deaths (8 with liraglutide and 1 with semaglutide) and 11 life-threatening outcomes (4 associated with liraglutide and 7 with semaglutide) were reported. The fatal outcomes occurred primarily among men (8 out of 9) resulting from completed suicidal attempts and depression.

CONCLUSION

Psychiatric adverse events comprised only 1.2% of the total reports for semaglutide, liraglutide, and tirzepatide. However, the severity and fatal outcomes of some of these reports warrant further investigation.

Gut microbiota and type 2 diabetes mellitus: a focus on the gut-brain axis

Type 2 diabetes mellitus (T2DM) has become one of the most serious public healthcare challenges, contributing to increased mortality and disability. In the past decades, significant progress has been made in understanding the pathogenesis of T2DM. Mounting evidence suggested that gut microbiota (GM) plays a significant role in the development of T2DM. Communication between the GM and the brain is a complex bidirectional connection, known as the "gut-brain axis," via the nervous, neuroendocrine, and immune systems. Gut-brain axis has an essential impact on various physiological processes, including glucose metabolism, food intake, gut motility, etc. In this review, we provide an outline of the gut-brain axis. We also highlight how the dysbiosis of the gut-brain axis affects glucose homeostasis and even results in T2DM.

Metabolic disorders in prediabetes: From mechanisms to therapeutic management

Diabetes, one of the world's top ten diseases, is known for its high mortality and complication rates and low cure rate. Prediabetes precedes the onset of diabetes, during which effective treatment can reduce diabetes risk. Prediabetes risk factors include high-calorie and high-fat diets, sedentary lifestyles, and stress. Consequences may include considerable damage to vital organs, including the retina, liver, and kidneys. Interventions for treating prediabetes include a healthy lifestyle diet and pharmacological treatments. However, while these options are effective in the short term, they may fail due to the difficulty of long-term implementation. Medications may also be used to treat prediabetes. This review examines prediabetic treatments, particularly metformin, glucagon-like peptide-1 receptor agonists, sodium glucose cotransporter 2 inhibitors, vitamin D, and herbal medicines. Given the remarkable impact of prediabetes on the progression of diabetes mellitus, it is crucial to intervene promptly and effectively to regulate prediabetes. However, the current body of research on prediabetes is limited, and there is considerable confusion surrounding clinically relevant medications. This paper aims to provide a comprehensive summary of the pathogenesis of pre-diabetes mellitus and its associated therapeutic drugs. The ultimate goal is to facilitate the clinical utilization of medications and achieve efficient and timely control of diabetes mellitus.

Practical guide: Glucagon-like peptide-1 and dual glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptor agonists in diabetes mellitus

In 2005, exenatide became the first approved glucagon-like peptide-1 receptor agonist (GLP-1 RA) for type 2 diabetes mellitus (T2DM). Since then, numerous GLP-1 RAs have been approved, including tirzepatide, a novel dual glucose-dependent insulinotropic polypeptide (GIP)/GLP-1 RA, which was approved in 2022. This class of drugs is considered safe with no hypoglycemia risk, making it a common second-line choice after metformin for treating T2DM. Various considerations can make selecting and switching between different GLP-1 RAs challenging. Our study aims to provide a comprehensive guide for the usage of GLP-1 RAs and dual GIP and GLP-1 RAs for the management of T2DM.

New insights into nanomedicines for oral delivery of glucagon-like peptide-1 analogs

Type 2 diabetes mellitus (T2DM) is a metabolic disorder that arises when the body cannot respond fully to insulin, leading to impaired glucose tolerance. Currently, the treatment embraces non-pharmacological actions (e.g., diet and exercise) co-associated with the administration of antidiabetic drugs. Metformin is the first-line treatment for T2DM; nevertheless, alternative therapeutic strategies involving glucagon-like peptide-1 (GLP-1) analogs have been explored for managing the disease. GLP-1 analogs trigger insulin secretion and suppress glucagon release in a glucose-dependent manner thereby, reducing the risk of hyperglycemia. Additionally, GLP-1 analogs have an extended plasma half-life compared to the endogenous peptide due to their high resistance to degradation by dipeptidyl peptidase-4. However, GLP-1 analogs are mainly administered via subcutaneous route, which can be inconvenient for the patients. Even considering an oral delivery approach, GLP-1 analogs are exposed to the harsh conditions of the gastrointestinal tract (GIT) and the intestinal barriers (mucus and epithelium). Hereupon, there is an unmet need to develop non-invasive oral transmucosal drug delivery strategies, such as the incorporation of GLP-1 analogs into nanoplatforms, to overcome the GIT barriers. Nanotechnology has the potential to shield antidiabetic peptides against the acidic pH and enzymatic activity of the stomach. In addition, the nanoparticles can be coated and/or surface-conjugated with mucodiffusive polymers and target intestinal ligands to improve their transport through the intestinal mucus and epithelium. This review focuses on the main hurdles associated with the oral administration of GLP-1 and GLP-1 analogs, and the nanosystems developed to improve the oral bioavailability of the antidiabetic peptides. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

Population pharmacokinetics of the GIP/GLP receptor agonist tirzepatide

Tirzepatide is a first-in-class glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptor agonist approved as for the treatment of type 2 diabetes mellitus. A population-based pharmacokinetic (PK) model was developed from 19 pooled studies. Tirzepatide pharmacokinetics were well-described by a two-compartment model with first order absorption and elimination. The tirzepatide population PK model utilized a semimechanistic allometry model to describe the relationship between body size and tirzepatide PK. The half-life of tirzepatide was ~5 days and enabled sustained exposure with once-weekly subcutaneous dosing. The covariate analysis suggested that adjustment of the dose regimen based on demographics or subpopulations was unnecessary. The tirzepatide PK model can be used to predict tirzepatide exposure for various scenarios or populations.

Effect of tirzepatide on albuminuria levels and renal function in patients with type 2 diabetes mellitus: A systematic review and multilevel meta-analysis

AIM

The present systematic review aimed to summarize the available evidence from published randomized controlled trials (RCTs) regarding the effect of tirzepatide on albuminuria levels and renal function in patients with type 2 diabetes mellitus.

MATERIALS AND METHODS

Medline (via PubMed), Cochrane Library and Scopus were searched until 20 October 2023. Double-independent study selection, data extraction and quality assessment were performed. Evidence was pooled with a three-level mixed-effects meta-analysis.

RESULTS

In total, 9533 participants from eight RCTs were analysed. All RCTs had a low risk of bias, according to the Cochrane Collaboration tool (RoB2). Tirzepatide was associated with a significantly greater reduction in urine albumin-to-creatinine ratio compared with controls [mean difference (MD) -26.9%; 95% confidence interval (CI) (-34.76, -19.04); p < .001; level of evidence (LoE) moderate]. This effect remained significant in participants with baseline urine albumin-to-creatinine ratio ≥30 mg/g [MD -41.42%; 95% CI (-54.38, -28.45); p < .001; LoE moderate]. Based on subgroup analysis, the comparative effect of tirzepatide was significant against placebo and the insulin regimen, whereas no difference was observed compared with semaglutide. The beneficial effect of tirzepatide on albuminuria levels remained significant across all investigated doses (5, 10 and 15 mg), showing a dose-response relationship. A neutral effect was observed on the estimated glomerular filtration rate [MD 0.39 ml/min/1.73m2 ; 95% CI (-0.64, 1.42); p = .46; LoE moderate].

CONCLUSION

Our findings suggest that tirzepatide probably leads to a significant reduction in albuminuria across all administered doses, while its use is associated with a neutral effect on creatinine clearance as a measure of renal function.

Reduction of prevalence of patients meeting the criteria for metabolic syndrome with tirzepatide: a post hoc analysis from the SURPASS Clinical Trial Program

BACKGROUND

Metabolic syndrome is characterized as the co-occurrence of interrelated cardiovascular risk factors, including insulin resistance, hyperinsulinemia, abdominal obesity, dyslipidemia and hypertension. Once weekly tirzepatide is approved in the US and EU for the treatment of type 2 diabetes (T2D) and obesity. In the SURPASS clinical trial program for T2D, tirzepatide demonstrated greater improvements in glycemic control, body weight reduction and other cardiometabolic risk factors versus placebo, subcutaneous semaglutide 1 mg, insulin degludec, and insulin glargine. This post hoc analysis assessed the effect of tirzepatide use on the prevalence of patients meeting the criteria for metabolic syndrome across SURPASS 1-5.

METHODS

Metabolic syndrome was defined as having ≥ 3 of 5 criteria according to the US National Cholesterol Education Program: Adult Treatment Panel III. Analyses were based on on-treatment data at the primary endpoint from patients adherent to treatment (taking ≥ 75% study drug). A logistic regression model with metabolic syndrome status as the response variable, metabolic syndrome status at the baseline visit as an adjustment, and randomized treatment as fixed explanatory effect was used. The effect of tirzepatide use on the prevalence of patients meeting the criteria for metabolic syndrome by categorical weight loss, background medication and gender were assessed.

RESULTS

In SURPASS, the prevalence of patients meeting the criteria for metabolic syndrome at baseline was 67-88% across treatment groups with reductions at the primary endpoint to 38-64% with tirzepatide versus 64-82% with comparators. Reductions in the prevalence of patients meeting the criteria for metabolic syndrome was significantly greater with all tirzepatide doses versus placebo, semaglutide 1 mg, insulin glargine, and insulin degludec (p < 0.001). Individual components of metabolic syndrome were also reduced to a greater extent with tirzepatide vs comparators. Greater reductions in body weight were associated with greater reductions in the prevalence of patients meeting the criteria for metabolic syndrome and its individual components. Background SGLT2i or sulfonylurea use or gender did not impact the change in prevalence of patients meeting the criteria for metabolic syndrome.

CONCLUSIONS

In this post hoc analysis, tirzepatide at all doses studied was associated with a greater reduction in the prevalence of patients meeting the criteria for metabolic syndrome compared to placebo, semaglutide 1 mg, insulin degludec, and insulin glargine. Although more evidence is needed, these data would support greater potential improvement in cardiovascular risk factor profile with tirzepatide treatment in people across the continuum of T2D.

The Body weight Reducing Effects of Tirzepatide in People with and without Type 2 Diabetes: A Review on Efficacy and Adverse Effects

Obesity is becoming more frequent and has several negative health impacts. Recent advances in weight management strategies have primarily resided in pharmaceutical treatments, and the glucagon-like peptide-1 (GLP-1) receptor agonists have shown great potential in terms of body weight reduction in addition to improving glycemic control in patients with type 2 diabetes (T2D). Recently, the dual GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) receptor agonist tirzepatide has been developed. Tirzepatide has shown strong effects on glycated hemoglobin (HbA1C) levels in several clinical trials including participants with T2D (SURPASS program). In addition to its lowering effect on HbA1C, tirzepatide leads to substantial reductions in body weight, and a series of clinical trials (SURMOUNT program) have investigated the effects on body weight as the primary outcome. In these two trial programs, tirzepatide in doses of 5 mg to 15 mg administered subcutaneously once weekly resulted in body weight reduction of up to 15% in participants with T2D and up to 21% in participants without T2D, despite comparable baseline bodyweight. Across the two trial programs, adverse effects were mainly gastrointestinal (nausea, diarrhea, and vomiting) occurring with similar incidences of vomiting and lower incidences of diarrhea and nausea in trial participants with T2D compared to trials participants without T2D. Overall, discontinuation due to adverse events occurred in 3-7% of participants with no major differences between individuals with and without T2D. The higher weight-reducing efficacy of tirzepatide in trial participants without T2D is currently unexplained and may be partly reflected in dissimilarities in frequencies of gastrointestinal adverse events. The weight reducing effects of tirzepatide hold great promise for weight management in obese patients regardless of the presence of T2D.

Tirzepatide: A Review in Type 2 Diabetes

Tirzepatide (Mounjaro®), a first-in-class dual incretin agonist of the glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors, is approved for use as an adjunct to diet and exercise to improve glycaemic control in adults with type 2 diabetes mellitus (T2DM) in the USA, EU, Japan and other countries. It comes as single-dose prefilled pens and single-dose vials. In phase III SURPASS trials, once-weekly subcutaneous tirzepatide, as monotherapy or add-on-therapy to oral glucose-lowering medications and insulin, was superior to the GLP-1 receptor agonists (RAs) dulaglutide 0.75 mg and semaglutide 1 mg as well as basal and prandial insulin for glycaemic control and weight loss in adults with inadequately controlled T2DM. Tirzepatide was generally well tolerated, with a safety profile consistent with that of GLP-1 RAs. Tirzepatide was associated with a low risk of clinically significant or severe hypoglycaemia and no increased risk of major adverse cardiovascular events. Adverse events were mostly mild to moderate in severity, with the most common being gastrointestinal events including nausea, diarrhoea, decreased appetite and vomiting. In conclusion, tirzepatide is a valuable addition to the treatment options for T2DM.

Narrative Review of Effects of Glucagon-Like Peptide-1 Receptor Agonists on Bone Health in People Living with Obesity

Glucagon-like peptide-1 Receptor agonists (GLP-1Ras) such as liraglutide and semaglutide have been recently approved as medications for chronic weight management in people living with obesity (PwO); GLP-1 may enhance bone metabolism and improve bone quality. However, the effects of GLP-1Ras on skeletal health remain to be determined and that's the purpose of this narrative review. Nevertheless, bone consequences of intentional weight loss interventions in PwO are well known: (i) significant weight loss induced by caloric restriction and bariatric surgery results in accelerated bone turnover and bone loss, and (ii) unlike caloric restriction interventions, PwO experience a substantial deterioration in bone microarchitecture and strength associated with an increased risk of fracture after bariatric surgery especially malabsorptive procedures. Liraglutide seems to have a positive effect on bone material properties despite significant weight loss in several rodent models. However, most of positive effects on bone mineral density and microarchitecture were observed at concentration much higher than approved for obesity care in humans. No data have been reported in preclinical models with semaglutide. The current evidence of the effects of GLP-1Ra on bone health in PwO is limited. Indeed, studies on the use of GLP-1Ra mostly included patients with diabetes who were administered a dose used in this condition, did not have adequate bone parameters as primary endpoints, and had short follow-up periods. Further studies are needed to investigate the bone impact of GLP-1Ra, dual- and triple-receptor agonists for GLP-1, glucose-dependent insulin releasing polypeptide (GIP), and glucagon in PwO.

Tirzepatide prevents neurodegeneration through multiple molecular pathways

BACKGROUND

Several evidence demonstrated that glucagon-like peptide 1 receptor agonists (GLP1-RAs) reduce the risk of dementia in type 2 diabetes patients by improving memory, learning, and overcoming cognitive impairment. In this study, we elucidated the molecular processes underlying the protective effect of Tirzepatide (TIR), a dual glucose-dependent insulinotropic polypeptide receptor agonist (GIP-RA)/ GLP-1RA, against learning and memory disorders.

METHODS

We investigated the effects of TIR on markers of neuronal growth (CREB and BDNF), apoptosis (BAX/Bcl2 ratio) differentiation (pAkt, MAP2, GAP43, and AGBL4), and insulin resistance (GLUT1, GLUT4, GLUT3 and SORBS1) in a neuroblastoma cell line (SHSY5Y) exposed to normal and high glucose concentration. The potential role on DNA methylation of genes involved in neuroprotection and epigenetic modulators of neuronal growth (miRNA 34a), apoptosis (miRNA 212), and differentiation (miRNA 29c) was also investigated. The cell proliferation was detected by measuring Ki-67 through flow cytometry. The data were analysed by SPSS IBM Version 23 or GraphPad Prism 7.0 software and expressed as the means ± SEM. Differences between the mean values were considered significant at a p-value of < 0.05. GraphPad Prism software was used for drawing figures.

RESULTS

For the first time, it was highlighted: (a) the role of TIR in the activation of the pAkt/CREB/BDNF pathway and the downstream signaling cascade; (b) TIR efficacy in neuroprotection; (c) TIR counteracting of hyperglycemia and insulin resistance-related effects at the neuronal level.

CONCLUSIONS

We demonstrated that TIR can ameliorate high glucose-induced neurodegeneration and overcome neuronal insulin resistance. Thus, this study provides new insight into the potential role of TIR in improving diabetes-related neuropathy.

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

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

ARTICLE HIGHLIGHTS

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

The Discovery and Development of Glucagon-Like Peptide-1 Receptor Agonists

Diabetes mellitus has become a serious life-threatening disease. As one of the new drugs for the treatment of diabetes, GLP-1 receptor agonists have attracted a lot of attention. Compared with traditional hypoglycemic drugs, GLP-1 receptor agonists have good safety and tolerability. To a certain extent, they overcome the problem of the short half-life of natural GLP-1 in vivo and can exist stably in patients for a long time, achieving good results in the treatment of diabetes, as well as improving the symptoms of some complications. The GLP-1 receptor agonists in the market are all peptide drugs. Compared with peptide drugs, small molecule agonists have the advantages of low cost and oral administration. In this article, we review the recent research progress of GLP-1 receptor agonists.

Hallmarks of the metabolic secretome

The identification of novel secreted factors is advancing at an unprecedented pace. However, there is a critical need to consolidate and integrate this knowledge to provide a framework of their diverse mechanisms, functional significance, and inter-relationships. Complicating this effort are challenges related to nonstandardized methods, discrepancies in sample handling, and inconsistencies in the annotation of unknown molecules. This Review aims to synthesize the rapidly expanding field of the metabolic secretome, encompassing the five major types of secreted factors: proteins, peptides, metabolites, lipids, and extracellular vesicles. By systematically defining the functions and detection of the components within the metabolic secretome, this Review provides a primer into the advances of the field, and how integration of the techniques discussed can provide a deeper understanding of the mechanisms underlying metabolic homeostasis and its disorders.

Evolution of GCGR family ligand-receptor extensive cross-interaction systems suggests a therapeutic direction for hyperglycemia in mammals

Glucose is essential to the physiological processes of vertebrates. Mammalian physiological stability requires a relatively stable blood glucose level (~5 mM), whereas other vertebrates have greater flexibility in regulating blood glucose (0.5-25 mM). GCGR family receptors play an important role in vertebrate glucose regulation. Here, we examine the evolution of the GCGR family ligand-receptor systems in different species. Comparatively, we discover that the conserved sequences among GCG family ligands lead to the non-specific activation of ligands across species. In particular, we observe that glucagon-like peptide 1 receptor (GLP1R), glucagon-like peptide 2 receptor (GLP2R), and glucagon-like receptor (GCGLR, also called GCRPR) are arbitrarily activated by other members of the ligand family in birds. Moreover, we reveal that Gallus gallus GLP2 (gGLP2) effectively activates mammalian GLP1R and improves glucose tolerance in diabetic mice. Our study has important implications for understanding blood glucose stabilization in vertebrates and demonstrates that gGLP2 may be a potential drug for treating type 2 diabetes.

Beyond glycemia: Comparing tirzepatide to GLP-1 analogues

Glucagon-like peptide-1 receptor analogs (GLP-1 RAs) have been an innovative and instrumental drug class in the management of both type 2 diabetes and obesity. Tirzepatide is a novel agent that acts as an agonist for both GLP-1 receptors and gastric inhibitory polypeptide (GIP) receptors, another incretin that lowers glucose and appetite. Although previous studies showed a lack of therapeutic benefit for GIP agonists, current studies show that the glucose lowering and weight loss effects of tirzepatide are at least as effective as GLP-1 RAs with a similar adverse effect profile. Some studies, though not conclusive, predict that tirzepatide may in fact be more potent than GLP-1 RAs at reducing weight. A thorough review of the studies that led to tirzepatide's approval allows for comparisons between tirzepatide and GLP-1 RAs; it also allows for predictions of tirzepatide's eventual place in therapy - an agent used preferentially over GLP-1 RAs in patients with or without diabetes desiring to lose weight.

Incretin hormone responses to carbohydrate and protein/fat are preserved in adults with sulfonylurea-treated KCNJ11 neonatal diabetes

The incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), are thought to be the main drivers of insulin secretion in individuals with sulfonylurea (SU)-treated KCNJ11 permanent neonatal diabetes. The aim of this study was to assess for the first time the incretin hormone response to carbohydrate and protein/fat in adults with sulfonylurea-treated KCNJ11 permanent neonatal diabetes compared with that of controls without diabetes. Participants were given a breakfast high in carbohydrate and an isocaloric breakfast high in protein/fat on two different mornings. Incremental area under the curve and total area under the curve (0-240 minutes) for total GLP-1 and GIP were compared between groups, using non-parametric statistical methods. Post-meal GLP-1 and GIP secretion were similar in cases and controls, suggesting this process is adenosine triphosphate-sensitive potassium channel-independent. Future research will investigate whether treatments targeting the incretin pathway are effective in individuals with KCNJ11 permanent neonatal diabetes who do not have good glycemic control on sulfonylurea alone.

Spatiotemporal regulation of GIPR signaling impacts glucose homeostasis as revealed in studies of a common GIPR variant

OBJECTIVE

Glucose-dependent insulinotropic polypeptide (GIP) has a role in controlling postprandial metabolic tone. In humans, a GIP receptor (GIPR) variant (Q354, rs1800437) is associated with a lower body mass index (BMI) and increased risk for Type 2 Diabetes. To better understand the impacts of GIPR-Q354 on metabolism, it is necessary to study it in an isogeneic background to the predominant GIPR isoform, E354. To accomplish this objective, we used CRISPR-CAS9 editing to generate mouse models of GIPR-Q354 and GIPR-E354. Here we characterize the metabolic effects of GIPR-Q354 variant in a mouse model (GIPR-Q350).

METHODS

We generated the GIPR-Q350 mice for in vivo studies of metabolic impact of the variant. We isolated pancreatic islets from GIPR-Q350 mice to study insulin secretion ex vivo. We used a β-cell cell line to understand the impact of the GIPR-Q354 variant on the receptor traffic.

RESULTS

We found that female GIPR-Q350 mice are leaner than littermate controls, and male GIPR-Q350 mice are resistant to diet-induced obesity, in line with the association of the variant with reduced BMI in humans. GIPR-Q350 mice of both sexes are more glucose tolerant and exhibit an increased sensitivity to GIP. Postprandial GIP levels are reduced in GIPR-Q350 mice, revealing feedback regulation that balances the increased sensitivity of GIP target tissues to secretion of GIP from intestinal endocrine cells. The increased GIP sensitivity is recapitulated ex vivo during glucose stimulated insulin secretion assays in islets. Generation of cAMP in islets downstream of GIPR activation is not affected by the Q354 substitution. However, post-activation traffic of GIPR-Q354 variant in β-cells is altered, characterized by enhanced intracellular dwell time and increased localization to the Trans-Golgi Network (TGN).

CONCLUSIONS

Our data link altered intracellular traffic of the GIPR-Q354 variant with GIP control of metabolism. We propose that this change in spatiotemporal signaling underlies the physiologic effects of GIPR-Q350/4 and GIPR-E350/4 in mice and humans. These findings contribute to a more complete understanding of the impact of GIPR-Q354 variant on glucose homeostasis that could perhaps be leveraged to enhance pharmacologic targeting of GIPR for the treatment of metabolic disease.

Evaluating Glycemic Control Efficacy and Safety of the Oral Small Molecule Glucagon-Like Peptide 1 Receptor Agonist Danuglipron in Type 2 Diabetes Patients: A Systemic Review and Meta-Analysis

Introduction

Diabetes Mellitus (DM) is a significant global health concern, with Type 2 DM (T2DM) being highly prevalent. Glucagon-Like Peptide 1 receptor agonists (GLP-1RA), such as Danuglipron, offer potential benefits in T2DM management. This meta-analysis examines the safety and efficacy of Danuglipron, focusing on adverse outcomes and glycemic parameters.

Methods

A systematic search was conducted in PubMed, Scopus, and Cochrane Library for RCTs involving Danuglipron till August 2023, following PRISMA guidelines. The Cochrane risk-of-bias tool was used for quality assessment. Adverse outcomes (diarrhea, nausea, vomiting, headache, decreased appetite, dyspepsia, dizziness) and glycemic parameters like changes in HbA1C, fasting plasma glucose (FPG), and body weight were analyzed.

Results

Four RCTs published from 2021 to 2023 were included. Both doses of Danuglipron were associated with diarrhea (RR=2.66, 90% CI: 1.32 to 5.35, p=0.02), nausea (RR=5.5, 90% CI: 3.4 to 8.88, p<0.00001), and vomiting (RR=5.98, 90% CI: 2.93 to 12.23, p=0.0001). The 120mg dose showed decreased appetite (RR=3.46, 90% CI: 1.57 to 7.62, p=0.01), dyspepsia (RR=4.04, 90% CI: 1.93 to 8.43, p=0.002), and dizziness (RR=5.08, 90% CI: 1.45 to 17.82, p=0.03). Reductions in HbA1C (SMD -1.09, 90% CI -1.39 to -0.8, p < 0.00001), FPG (SMD -1.10, 90% CI -1.46 to -0.75, p < 0.00001), and body weight (SMD -1.08, 90% CI -1.42 to -0.74, p < 0.00001) were observed for both doses.

Conclusion

Danuglipron demonstrates potential for glycemic control and weight reduction in T2DM. Adverse outcomes include diarrhea, nausea, vomiting, and decreased appetite, with dose-related effects. Clinicians must weigh benefits against side effects when considering Danuglipron for T2DM management.

Impact of tirzepatide in a patient with type 1 diabetes and obesity: A case report

BACKGROUND

The purpose of this case report is to describe the use of tirzepatide, a glucose-dependent insulinotropic polypeptide/glucagon-like peptide-1 receptor agonist, in a patient with type 1 diabetes mellitus (T1DM) and obesity.

CASE SUMMARY

A 23-year-old female with T1DM since the age of 10 years was referred to an endocrinology clinic for specialized diabetes care with a pharmacist owing to increasing insulin requirements and resistance. At baseline, the patient weighed 195 pounds (86.64 kg), which had increased significantly by approximately 40 pounds in the last year, and had a body mass index of 38 kg/m2 and hemoglobin A1c (HbA1c) level of 7.4%. She used hybrid closed loop insulin pump technology with continuous glucose monitoring in 100% automation mode. The patient used on average 55.4 units of basal insulin and 26.5 units of bolus per day (total daily dose, 81.9 units) with a time in range (TIR) of 31%. The patient was started on tirzepatide 2.5 mg weekly and titrated to 7.5 mg weekly with 4-week dose titrations. After 12 weeks, the patient's TIR had doubled to 61% with improvements in glucose variability, insulin requirements had decreased to 57.6 units per day, HbA1c had decreased to 6.9%, daily carbohydrates had decreased by approximately 24%, and weight had decreased to 188 pounds (-7 lbs).

PRACTICE IMPLICATIONS

With additional studies, tirzepatide may be a safe and effective option for patients with T1DM and obesity to improve glycemic control, reduce insulin requirements, and promote weight loss.

Achieving Normoglycemia With Tirzepatide: Analysis of SURPASS 1-4 Trials

OBJECTIVE

Tirzepatide is a novel single-molecule glucose-dependent insulinotropic polypeptide/glucagon-like peptide 1 receptor agonist, which demonstrated unprecedented improvements in glycemic control and body weight reduction, in the SURPASS phase 3 program. In this exploratory analysis, we aimed to characterize tirzepatide-treated participants who achieved HbA1c <5.7% and evaluate changes in clinical markers associated with long-term cardiometabolic health.

RESEARCH DESIGN AND METHODS

Baseline characteristics and change from baseline to week 40 for several efficacy and safety parameters were analyzed according to HbA1c attainment category (<5.7%, 5.7-6.5%, and >6.5%) using descriptive statistics in participants taking ≥75% of treatment doses, without rescue medication, in the SURPASS 1-4 trials (N = 3,229). Logistic regression models with tirzepatide doses adjusted as a covariate were used to obtain odds ratios and assess the impact of patient characteristics achieving an HbA1c <5.7%.

RESULTS

Tirzepatide-treated participants who achieved HbA1c <5.7% were slightly younger, with a shorter duration of diabetes and lower HbA1c value at baseline compared with those who did not achieve HbA1c <5.7%. In addition, they showed greater improvements in HbA1c, body weight, waist circumference, blood pressure, liver enzymes, and lipid parameters without increasing hypoglycemia risk.

CONCLUSIONS

Normoglycemia was unprecedently achieved in a significant proportion of participants in the SURPASS clinical program, without increasing hypoglycemia risk, and was associated with an overall improvement in metabolic health.

Mechanisms of action of incretin receptor based dual- and tri-agonists in pancreatic islets

Simultaneous activation of the incretin G-protein-coupled receptors (GPCRs) via unimolecular dual-receptor agonists (UDRA) has emerged as a new therapeutic approach for type 2 diabetes. Recent studies also advocate triple agonism with molecules also capable of binding the glucagon receptor. In this scoping review, we discuss the cellular mechanisms of action (MOA) underlying the actions of these novel and therapeutically important classes of peptide receptor agonists. Clinical efficacy studies of several UDRAs have demonstrated favorable results both as monotherapies and when combined with approved hypoglycemics. Although the additive insulinotropic effects of dual glucagon-like peptide-1 receptor (GLP-1R) and glucose-dependent insulinotropic peptide receptor (GIPR) agonism were anticipated based on the known actions of either glucagon-like peptide-1 (GLP-1) or glucose-dependent insulinotropic peptide (GIP) alone, the additional benefits from GCGR were largely unexpected. Whether additional synergistic or antagonistic interactions among these G-protein receptor signaling pathways arise from simultaneous stimulation is not known. The signaling pathways affected by dual- and tri-agonism require more trenchant investigation before a comprehensive understanding of the cellular MOA. This knowledge will be essential for understanding the chronic efficacy and safety of these treatments.

Development of a novel Fc fusion protein dual glucagon-like peptide-1 and gastric inhibitory polypeptide receptor agonists

AIM

To develop and investigate an imbalanced dual gastric inhibitory polypeptide receptor (GIPR)/glucagon-like peptide-1 receptor (GLP-1 R) agonist with Fc fusion protein structure.

METHODS

We designed and constructed an Fc fusion protein that is a dual agonist (HEC-CG115) with an empirically optimized potency ratio for GLP-1R and GIPR. The long-term effects of HEC-CG115 on body weight and glycaemic control were evaluated in diet-induced obese mice and diabetic db/db mice. Repeat dose toxicity assays were performed to investigate the safety profile of HEC-CG115 in Sprague-Dawley rats.

RESULTS

HEC-CG115 displayed high potency for GIPR and relatively low potency for GLP-1R, and we labelled it 'imbalanced'. In animal models, HEC-CG115 (3 nmol/kg) led to more weight loss than semaglutide at a higher dose (10 nmol/kg) in diet-induced obese model mice. HEC-CG115 (one dose every 3 days) reduced fasting blood glucose and glycated haemoglobin levels similar to those after semaglutide (once daily) at the same dose. In a 4-week subcutaneous toxicity study conducted to assess the biosafety of HEC-CG115, the no observed adverse effect level was determined to be 3 mg/kg.

CONCLUSION

HEC-CG115 is a novel Fc fusion protein with imbalanced dual agonism that shows superior weight loss, glycaemic control and metabolic improvement in animal models, and has an optimal safety profile according to a repeat-dose toxicity study. Therefore, the use of HEC-CG115 appears to be safe and effective for the treatment of obesity and type 2 diabetes.

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.

Safety issues of tirzepatide (pancreatitis and gallbladder or biliary disease) in type 2 diabetes and obesity: a systematic review and meta-analysis

Purpose

A systematic review and meta-analysis was conducted to synthesize the available data from clinical trials and assess the safety issues of tirzepatide (pancreatitis and gallbladder or biliary disease) in type 2 diabetes (T2D) and obesity.

Methods

A systematic search was conducted in three electronic databases, namely Embase, PubMed, and the Cochrane Library, up until March 1, 2023, to identify randomized controlled trials (RCTs) comparing tirzepatide to either placebo or active hypoglycemic drugs in individuals with T2D and obesity. Heterogeneity was assessed using the I2 value and Cochran's Q test, and a fixed effects model was employed to estimate the safety profile of tirzepatide. The safety outcomes of interest, including pancreatitis, the composite of gallbladder or biliary diseases, cholecystitis, and cholelithiasis and biliary diseases, were evaluated. (The composite of gallbladder or biliary diseases incorporated cholelithiasis, cholecystitis, other gallbladder disorders, and biliary diseases.).

Results

A total of nine trials with 9871 participants (6828 in the tirzepatide group and 3043 in the control group) that met the pre-specified criteria were included. When compared to all control groups consisting of basal insulin (glargine or degludec), selective GLP1-RA (dulaglutide or semaglutide once weekly), and placebo, an increased risk of pancreatitis was not found to be significantly associated with tirzepatide (RR 1.46, [95% CI] 0.59 to 3.61; I2 = 0.0%, p = 0.436). For gallbladder or biliary disease, the composite of gallbladder or biliary disease was significantly associated with tirzepatide compared with placebo or basal insulin (RR 1.97, [95% CI] 1.14 to 3.42; I2 = 0.0%, p = 0.558), but not with the risk of cholelithiasis, cholecystitis or biliary diseases.

Conclusion

Based on the currently available data, tirzepatide appears to be safe regarding the risk of pancreatitis. However, the increased risk of the composite outcome of gallbladder or biliary diseases observed in RCTs warrants further attention from physicians in clinical practice.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO, identifier CRD42023412400.

Potential Therapeutic Strategies in the Treatment of Metabolic-Associated Fatty Liver Disease

Metabolic-associated Fatty Liver Disease is one of the outstanding challenges in gastroenterology. The increasing incidence of the disease is undoubtedly connected with the ongoing obesity pandemic. The lack of specific symptoms in the early phases and the grave complications of the disease require an active approach to prompt diagnosis and treatment. Therapeutic lifestyle changes should be introduced in a great majority of patients; but, in many cases, the adherence is not satisfactory. There is a great need for an effective pharmacological therapy for Metabolic-Associated Fatty Liver Disease, especially before the onset of steatohepatitis. Currently, there are no specific recommendations on the selection of drugs to treat liver steatosis and prevent patients from progression toward more advanced stages (steatohepatitis, cirrhosis, and cancer). Therefore, in this Review, we provide data on the clinical efficacy of therapeutic interventions that might improve the course of Metabolic-Associated Fatty Liver Disease. These include the drugs used in the treatment of obesity and hyperlipidemias, as well as affecting the gut microbiota and endocrine system, and other experimental approaches, including functional foods. Finally, we provide advice on the selection of drugs for patients with concomitant Metabolic-Associated Fatty Liver Disease.

Beta-cell function in type 2 diabetes (T2DM): Can it be preserved or enhanced?

Type 2 diabetes (T2DM) is a complex metabolic disorder manifested by hyperglycemia, insulin resistance, and deteriorating beta-cell function. A way to prevent progression of the disease might be to enhance beta-cell function and insulin secretion. However, most previous studies examined beta-cell function while patients were using glycemia-lowering agents without an adequate period off medications (washout). In the present review we focus on studies with a washout period. We performed a literature search (2010 to June 2021) using beta-cell function and enhancement. The evidence shows that beta-cell function can be enhanced. Bariatric surgery and very low calorie diets show improvement in beta-cell function in many individuals. In addition, use of glucagon-like peptide-1 receptor agonists for prolonged periods (3 years or more) can also lead to improvement of beta-cell function. Further research is needed to understand the mechanisms leading to improved beta-cell function and identify agents that could enhance beta-cell function in patients with T2DM.

Efficacy of Regimens in the Treatment of Latent Autoimmune Diabetes in Adults: A Network Meta-analysis

INTRODUCTION

Latent autoimmune diabetes in adults (LADA) is a highly heterogeneous autoimmune condition with clinical and genetic characteristics that fall between those of type 1 diabetes mellitus and type 2 diabetes mellitus; therefore, there are no uniform criteria for the selection of therapeutic agents. We conducted a network meta-analysis to evaluate the efficacy of various therapeutic agents for LADA by comparing their effects on various indicators used to reflect LADA.

METHODS

We searched the PubMed, Cochrane Library, Embase and Web of Science databases from their inception to March 2023 and collected data from 14 randomized controlled trials on glucose-lowering drugs for LADA, including 23 studies and 15 treatment regimens. The effectiveness of drugs was ranked and evaluated by combining surface under the cumulative ranking (SUCRA) plots and forest plots. Factors that may influence study heterogeneity were also searched and analyzed by combining subgroup analysis, publication bias, funnel plots and sensitivity analysis.

RESULTS

The results of the network meta-analysis showed that insulin had the most significant effect on the control of change from baseline in glycosylated hemoglobin, type A1 (ΔHbA1c). Insulin combined with dipeptidyl peptidase-4 (DPP-4) inhibitors performed the best in reducing fasting blood glucose and body mass index. Treatment regimens involving thiazolidinediones were the most advantageous in HbA1c, fasting C-peptide and postprandial C-peptide control. Longer dosing may be more beneficial in maintaining islet β-cell function in the LADA population.

CONCLUSION

LADA is an immune condition with high heterogeneity, and treatment should be administered according to the C-peptide level of the LADA population. For this population with LADA with a certain level of β-cell function, combinations of insulin with DPP-4 inhibitors or thiazolidinediones probably can be more effective treatment options to maintain islet function and normal blood glucose.

TRIAL REGISTRATION

PROSPERO CRD42023410795.

Synergistic Combinations of Gut- and Pancreas-Hormone-Based Therapies: Advancements in Treatments for Metabolic Diseases

Metabolic diseases, such as obesity, type 2 diabetes mellitus (T2DM), cardiovascular disease, and liver disease, have become increasingly prevalent around the world. As an alternative to bariatric surgery, glucagon-like peptide 1 (GLP-1) receptor agonists have been at the forefront of weight loss medication to combat these metabolic complications. Recently, there has been an exciting rapid emergence of new weight loss medications that combine GLP-1 receptor (GLP-1R) agonists with other gut- and pancreatic-derived hormones, such as glucose-dependent insulinotropic polypeptide (GIP) and glucagon (GCG) receptor agonists. Dual-agonist (GLP-1/GIP and GLP-1/GCG) and tri-agonist (GLP-1/GIP/GCG) administration generally result in greater weight loss, reduction of blood sugar and lipid levels, restoration of tissue function, and improvement in whole-body substrate metabolism compared to when GLP-1R agonists are used alone. The aim of this review is to summarize the recent literature of both preclinical and clinical studies on how these emerging gut-peptide therapies further improve weight loss and metabolic health outcomes for various metabolic diseases.

Tirzepatide-Induced Gastrointestinal Manifestations: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis determine how frequently and how seriously gastrointestinal manifestations affect people with type 2 diabetes mellitus on tirzepatide. Tirzepatide is a recently developed drug that attempts to enhance type 2 diabetics' ability to regulate their blood sugar levels and promote weight reduction. Despite its potential benefits, clinical trials have revealed that the medication may lead to gastrointestinal side effects, including nausea, vomiting, decreased appetite, dyspepsia, constipation, and diarrhea. These side effects may negatively affect the drug's efficacy and patient tolerance. A comprehensive search of electronic databases such as PubMed, Web of Science, and Cochrane Library, was conducted to find pertinent studies reporting on the frequency and severity of gastrointestinal symptoms in type 2 diabetes patients receiving tirzepatide. This systematic review follows the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. Study selection, data extraction, and quality assessment were performed. Six randomized controlled trials with a total of 4,586 patients were included. Most patients received tirzepatide to regulate their blood sugar levels and promote weight reduction, and the comparators were placebo, glucagon-like peptide one receptor agonists drugs, and insulin degludec. The dose of tirzepatide was 5mg, 10mg, and 15mg weekly. The incidence rate of nausea in patients who receive tirzepatide was 20.43%, while the incidence rate in the comparators was 10.47%, and it was significantly higher in the tirzepatide arm than in the comparators (RR, 2.90; 95% CI, 1.89 to 4.44; P ≤ 0.00001). The incidence rate of vomiting in patients who receive tirzepatide was 9.05%, while the rate in the comparators was 4.86%, and it was significantly higher in the tirzepatide arm than in the comparators (RR, 2.69; 95% CI, 1.67 to 4.36; P ≤ 0.0001). The incidence rate of constipation in patients who receive tirzepatide was 2.54%, while the rate in the comparators was 0.856%, and it was significantly higher in the tirzepatide arm than in the comparators (RR, 3.08; 95% CI, 1.83 to 5.20; P ≤ 0.0001). The incidence rate of decreased appetite in patients who receive tirzepatide was 9.64%, while the rate in the comparators was 2.88%, and it was significantly higher in the tirzepatide arm than in the comparators (RR, 5.04; 95% CI, 3.01 to 8.45; P ≤ 0.00001). The incidence rate of diarrhea in patients who receive tirzepatide was 16.24%, while the rate in the comparators was 8.63%, and it was significantly higher in the tirzepatide arm than in the comparators (RR, 2.07; 95% CI, 1.60 to 2.68; P ≤ 0.00001). The incidence rate of dyspepsia in patients who receive tirzepatide was 7.13%, while the rate in the comparators was 3.31%, and it was significantly higher in the tirzepatide arm than in the comparators (RR, 2.52; 95% CI, 1.58 to 4.01; P ≤ 0.0001). Tirzepatide usage is linked to a significant prevalence of gastrointestinal symptoms, including nausea, constipation, decreased appetite, dyspepsia, diarrhea, and vomiting, in people with type 2 diabetes. These findings may influence clinical decision-making and patient counseling on the use of tirzepatide and have significant implications for the medication's tolerance and efficacy. To find ways to reduce these negative effects and improve therapy for type 2 diabetes patients, more research is required.

Advances in Research on Type 2 Diabetes Mellitus Targets and Therapeutic Agents

Diabetes mellitus is a chronic multifaceted disease with multiple potential complications, the treatment of which can only delay and prolong the terminal stage of the disease, i.e., type 2 diabetes mellitus (T2DM). The World Health Organization predicts that diabetes will be the seventh leading cause of death by 2030. Although many antidiabetic medicines have been successfully developed in recent years, such as GLP-1 receptor agonists and SGLT-2 inhibitors, single-target drugs are gradually failing to meet the therapeutic requirements owing to the individual variability, diversity of pathogenesis, and organismal resistance. Therefore, there remains a need to investigate the pathogenesis of T2DM in more depth, identify multiple therapeutic targets, and provide improved glycemic control solutions. This review presents an overview of the mechanisms of action and the development of the latest therapeutic agents targeting T2DM in recent years. It also discusses emerging target-based therapies and new potential therapeutic targets that have emerged within the last three years. The aim of our review is to provide a theoretical basis for further advancement in targeted therapies for T2DM.

The effects of subcutaneous Tirzepatide on obesity and overweight: a systematic review and meta-regression analysis of randomized controlled trials

Background

Despite the fact that obesity and overweight are serious major health problems worldwide, fighting against them is also considered a challenging issue. Several interventional studies have evaluated the potential weight-reduction effect of Tirzepatide. In order to obtain a better viewpoint from them, this study aimed to comprehensively investigate the effects of subcutaneous Tirzepatide on obesity and overweight.

Methods

Scopus, PubMed/Medline, Web of Science, Cochrane, and Embase databases were searched using standard keywords to identify all controlled trials investigating the weight loss effects of Tirzepatide. Pooled weighted mean difference and 95% confidence intervals were achieved by random-effects model analysis for the best estimation of outcomes. The statistical heterogeneity and publication bias were determined using the Cochran's Q test and I2 statistics and using the funnel plot and Egger's test, respectively.

Results

Twenty three treatments arm with 7062 participants' were included in this systematic review and meta-regression analysis. The pooled findings showed that Tirzepatide vs placebo significantly reduced body weight (weighted mean difference (WMD): -11.34 kg, 95% confidence interval (CI): -12.79 to -9.88, P< 0.001), body mass index (BMI) (WMD: -3.11 kg/m2, 95% CI: -4.36 to -1.86, P< 0.001), and waist circumference (WC) (WMD: -7.24 cm, 95% CI -10.12 to -4.36, P< 0.001). These reductions were even greater, especially with higher doses and duration of Tirzepatide.

Conclusions

Tirzepatide medication had significant effects on weight management with the reduction of body weight, BMI, and WC. Administration of Tirzepatide can be considered a therapeutic strategy for overweight or obese people.

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.

Comparing Efficacy and Safety of Different Doses of Tirzepatide for the Treatment of Type 2 Diabetes Mellitus: A Meta-Analysis of Randomized Controlled Trials

Our study assessed the efficacy and safety of the three primary tirzepatide (TZP) doses, 5 mg, 10 mg, and 15 mg using network meta-analysis to assess their relative impact on type 2 diabetes mellitus (T2DM) treatment. This study adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. Two authors independently screened online databases, including PubMed, Cochrane Library, and Embase. We employed the keywords "Type 2 diabetes OR T2DM or diabetes" AND "Tirzepatide OR LY3298176 OR twincretin OR dual glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptor agonist" AND "randomized controlled trial". The outcomes evaluated in this study comprised changes in hemoglobin (Hb)A1c levels from baseline (%), changes in weight from baseline (Kg), changes in fasting serum glucose from baseline (mg/dL), and occurrences of serious adverse events (SAE), adverse events (AE) and major adverse cardiovascular events (MACE). A total of eight studies met the inclusion criteria and were included in this meta-analysis. Our findings suggest that among the evaluated doses, TZP at 15 mg demonstrated superior effectiveness in reducing HbA1c, weight, and fasting serum glucose compared to doses of 10 mg and 5 mg. Notably, the reduction in HbA1c and weight showed a dose-dependent trend, with the 15 mg dose achieving the most substantial benefits. The safety analysis indicated that while serious adverse events and major adverse cardiovascular events (MACE) did not significantly differ among the three doses, the risk of overall adverse events was notably higher in the 10 mg and 15 mg TZP groups compared to the 5 mg group.