Incretin hormones and type 2 diabetes

Semaglutide for the management of diabesity: The real-world experience

BACKGROUND

Diabesity (diabetes as a consequence of obesity) has emerged as a huge healthcare challenge across the globe due to the obesity pandemic. Judicious use of antidiabetic medications including semaglutide is important for optimal management of diabesity as proven by multiple randomized controlled trials. However, more real-world data is needed to further improve the clinical practice.

AIM

To study the real-world benefits and side effects of using semaglutide to manage patients with diabesity.

METHODS

We evaluated the efficacy and safety of semaglutide use in managing patients with diabesity in a large academic hospital in the United States. Several parameters were analyzed including demographic information, the data on improvement of glycated hemoglobin (HbA1c), body weight reduction and insulin dose adjustments at 6 and 12 months, as well as at the latest follow up period. The data was obtained from the electronic patient records between January 2019 to May 2023.

RESULTS

106 patients (56 males) with type 2 diabetes mellitus (T2DM), mean age 60.8 ± 11.2 years, mean durations of T2DM 12.4 ± 7.2 years and mean semaglutide treatment for 2.6 ± 1.1 years were included. Semaglutide treatment was associated with significant improvement in diabesity outcomes such as mean weight reductions from baseline 110.4 ± 24.6 kg to 99.9 ± 24.9 kg at 12 months and 96.8 ± 22.9 kg at latest follow up and HbA1c improvement from baseline of 82 ± 21 mmol/mol to 67 ± 20 at 12 months and 71 ± 23 mmol/mol at the latest follow up. An insulin dose reduction from mean baseline of 95 ± 74 units to 76.5 ± 56.2 units was also observed at the latest follow up. Side effects were mild and mainly gastrointestinal like bloating and nausea improving with prolonged use of semaglutide.

CONCLUSION

Semaglutide treatment is associated with significant improvement in diabesity outcomes such as reduction in body weight, HbA1c and insulin doses without major adverse effects. Reviews of largescale real-world data are expected to inform better clinical practice decision making to improve the care of patients with diabesity.

Incretin mimetics and acute pancreatitis: enemy or innocent bystander?

PURPOSE OF REVIEW

The incretin enhancers and mimetics, including dipeptidyl peptidase-4 (DPP-4) inhibitors, GLP-1 receptor agonists (GLP-1RA) and GLP-1/GIP co-agonists, have become mainstays in the treatment of type 2 diabetes (T2D). Recently, the approval of certain GLP-1RA and GLP-1/GIP co-agonists for the treatment of obesity has broadened their popularity and use. In this review, we summarize the evidence for an association of these drugs with acute pancreatitis and other adverse events of special interest to gastroenterologists.

RECENT FINDINGS

In addition to pancreatic islets, GLP-1 receptors are expressed in the exocrine cells of the pancreas. There is inconsistent evidence for an association of DPP-4 inhibitors, GLP-1RA and co-agonists with risk for acute pancreatitis in individual trials. Meta-analyses of long-term randomized controlled trials indicate a small risk of acute pancreatitis associated with DPP-4 inhibitors but not GLP-1RA or co-agonists. Cholecystitis and cholelithiasis may be more common among those treated with GLP-1RA and GLP-1/GIP co-agonists. There is no evidence that any of these drugs are associated with an increased risk of pancreatic cancer.

SUMMARY

While drugs that leverage the incretin system are increasingly being used for patients with T2D and obesity, caution in warranted in those with a history of pancreatitis and gallbladder disease.

Liver kinase B1 (LKB1) regulates the epigenetic landscape of mouse pancreatic beta cells

Liver kinase B1 (LKB1/STK11) is an important regulator of pancreatic β-cell identity and function. Elimination of Lkb1 from the β-cell results in improved glucose-stimulated insulin secretion and is accompanied by profound changes in gene expression, including the upregulation of several neuronal genes. The mechanisms through which LKB1 controls gene expression are, at present, poorly understood. Here, we explore the impact of β cell-selective deletion of Lkb1 on chromatin accessibility in mouse pancreatic islets. To characterize the role of LKB1 in the regulation of gene expression at the transcriptional level, we combine these data with a map of islet active transcription start sites and histone marks. We demonstrate that LKB1 elimination from β-cells results in widespread changes in chromatin accessibility, correlating with changes in transcript levels. Changes occurred in hundreds of promoter and enhancer regions, many of which were close to neuronal genes. We reveal that dysregulated enhancers are enriched in binding motifs for transcription factors (TFs) important for β-cell identity, such as FOXA, MAFA or RFX6, and we identify microRNAs (miRNAs) that are regulated by LKB1 at the transcriptional level. Overall, our study provides important new insights into the epigenetic mechanisms by which LKB1 regulates β-cell identity and function.

Does glucose-dependent insulinotropic polypeptide receptor blockade as well as agonism have a role to play in management of obesity and diabetes?

Recent approval of the dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist, tirzepatide, for the management of type 2 diabetes mellitus (T2DM) has reinvigorated interest in exploitation of GIP receptor (GIPR) pathways as a means of metabolic disease management. However, debate has long surrounded the use of the GIPR as a therapeutic target and whether agonism or antagonism is of most benefit in management of obesity/diabetes. This controversy appears to be partly resolved by the success of tirzepatide. However, emerging studies indicate that prolonged GIPR agonism may desensitise the GIPR to essentially induce receptor antagonism, with this phenomenon suggested to be more pronounced in the human than rodent setting. Thus, deliberation continues to rage in relation to benefits of GIPR agonism vs antagonism. That said, as with GIPR agonism, it is clear that the metabolic advantages of sustained GIPR antagonism in obesity and obesity-driven forms of diabetes can be enhanced by concurrent GLP-1 receptor (GLP-1R) activation. This narrative review discusses various approaches of pharmacological GIPR antagonism including small molecule, peptide, monoclonal antibody and peptide-antibody conjugates, indicating stage of development and significance to the field. Taken together, there is little doubt that interesting times lie ahead for GIPR agonism and antagonism, either alone or when combined with GLP-1R agonists, as a therapeutic intervention for the management of obesity and associated metabolic disease.

Investigational and emerging gastric inhibitory polypeptide (GIP) receptor-based therapies for the treatment of obesity

INTRODUCTION

One billion people live with obesity. The most promising medications for its treatment are incretin-based therapies, based on enteroendocrine peptides released in response to oral nutrients, specifically glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP). The mechanisms by which GLP-1 receptor agonism cause weight reduction are becoming increasingly understood. However, the mechanisms by which GIP receptor-modulating medications cause weight loss remain to be clarified.

AREAS COVERED

This review describes GLP-1 and GIP physiology and explores the conflicting data regarding GIP and weight management. It details examples of how to reconcile the contradictory findings that both GIP receptor agonism and antagonism cause weight reduction. Specifically, it discusses the concept of 'biased agonism' wherein exogenous peptides cause different post-receptor signaling patterns than native ligands. It discusses how GIP effects in adipose tissue and the central nervous system may cause weight reduction. It describes GIP receptor-modulating compounds and their most current trials regarding weight reduction.

EXPERT OPINION

Effects of GIP receptor-modulating compounds on different tissues have implications for both weight reduction and other cardiometabolic diseases. Further study is needed to understand the implications of GIP agonism on not just weight reduction, but also cardiovascular disease, liver disease, bone health and fat storage.

Endoscopic duodenal mucosa ablation techniques for diabetes and nonalcoholic fatty liver disease: A systematic review

BACKGROUND

Type 2 diabetes mellitus (T2DM) is increasing at an alarming rate, and only 50% of patients with T2DM achieve or maintain adequate glycemic control with pharmacological therapies. Metabolic surgery demonstrated superior efficacy compared to medical therapy but is unfeasible for most patients with T2DM. Duodenal mucosal resurfacing (DMR) by hydrothermal mucosal ablation, recellularization via electroporation therapy (ReCET), and photodynamic therapy are novel endoscopic procedures that use thermal, electrical, and photochemical energy, respectively, to ablate and reset dysfunctional duodenal mucosa. We assessed the data on the effects of these techniques on glycemic control and nonalcoholic fatty liver disease (NAFLD).

METHODS

We systematically searched independently and in duplicate English and non-English language publications through January 31st, 2024. Outcomes assessed were an improvement in different metabolic health parameters and the safety of duodenal mucosal ablation (DMA) procedures. Outcomes were presented descriptively.

FINDINGS

We selected 12 reports reporting results from 3 randomized and 6 uncontrolled trials (seven evaluating DMR, two evaluating ReCET, all with a low risk of bias) for a total of 317 patients enrolled. DMA reduced HbA1c, fasting plasma glucose, and liver fat. When combined with newer antidiabetic drugs, it allowed insulin discontinuation in up to 86% patients. No major safety signal emerged.

CONCLUSIONS

All DMA techniques improve glucose homeostasis; DMR and ReCET appear to be safe in patients with T2DM. If confirmed by future randomized trials and by trials with histological endpoints in NAFLD, then DMA appears to be a promising alternative or complement option to medications for T2DM and NAFLD treatment.

FUNDING

This study received no funding.

Bibliometric analysis of research on the utilization of nanotechnology in diabetes mellitus and its complications

Aim: To identify hotspots in this field and provide insights into future research directions. Methods: Publications were retrieved from the Web of Science Core Collection database. R Bibliometrix software, VOSviewer and CiteSpace were used to perform the bibliometric and visualization analyses. Results: The analysis comprised 468 publications from 58 countries, with the United States, China and India being the leading contributors. 'Gene therapy', 'nanoparticles' and 'insulin therapy' are the primary focuses. 'Green synthesis', 'cytotoxicity', 'bioavailability' and 'diabetic foot ulcers' have gained prominence, signifying high-intensity areas of interest expected to persist as favored research topics in the future. Conclusion: This study delves into recent frontiers and topical research directions and provides valuable references for further research in this field.

Safety of native glucose-dependent insulinotropic polypeptide in humans

In this systematic review, we assessed the safety and possible safety events of native glucose-dependent insulinotropic polypeptide (GIP)(1-42) in human studies with administration of synthetic human GIP. We searched the PubMed database for all trials investigating synthetic human GIP(1-42) administration. A total of 67 studies were included. Study duration ranged from 30 min to 6 days. In addition to healthy individuals, the studies included individuals with impaired glucose tolerance, type 2 diabetes, type 1 diabetes, chronic pancreatitis and secondary diabetes, latent autoimmune diabetes in adults, diabetes caused by a mutation in the hepatocyte nuclear factor 1-alpha gene, end-stage renal disease, chronic renal insufficiency, critical illness, hypoparathyroidism, or cystic fibrosis-related diabetes. Of the included studies, 78% did not mention safety events, 10% of the studies reported that no safety events were observed in relation to GIP administration, and 15% of the studies reported safety events in relation to GIP administration with most frequently reported event being a moderate and transient increased heart rate. Gastrointestinal safety events, and changes in blood pressure were also reported. Plasma concentration of active GIP(1-42) increased linearly with dose independent of participant phenotype. There was no significant correlation between achieved maximal concentration of GIP(1-42) and reported safety events. Clearance rates of GIP(1-42) were similar between participant groups. In conclusion, the available data indicate that GIP(1-42) in short-term (up to 6 days) infusion studies is generally well-tolerated. The long-term safety of continuous GIP(1-42) administration is unknown.

A real-world data analysis of tirzepatide in the FDA adverse event reporting system (FAERS) database

Background

Tirzepatide, a glucose-dependent insulinotropic polypeptide (GIP) receptor and glucagon-like peptide-1 (GLP-1) receptor agonist, is indicated for chronic weight management in adults with obesity or overweight as an adjunct to a reduced-calorie diet and increased physical activity. However, the safety profile of Tirzepatide-associated adverse events requires comprehensive evaluation.

Methods

The AE reports from the first quarter of 2022 to the third quarter of 2023 were selected by exploring the FDA Adverse Event Reporting System (FAERS) database. The new and unexpected potenial AE signals were detected using the disproportionality analysis, including reporting odds ratio(ROR), the proportional reporting ratio (PRR) the Bayesian confidence propagation neural network (BCPNN) and the empirical Bayes geometric mean(EBGM). Then the MedDRA was used to systematically classify the results.

Results

A total of 1,904,481 case reports were obtained from 2022Q2 to 2023Q3. Forty-sixth tirzepatide-induced ADRs at the preferred terms (PTs) level are associated with 8 system organ class In addition, this study uncovered multiple anticipated ADRs, such as gastrooesophageal reflux disease, dyspepsia, and vomiting, in line with the drug labels. Moreover, unexpected and significant ADRs at PTs level, such as incorrect dose administered, injection site haemorrhage, and increased appetite, were discovered and linked to Injury, poisoning, and procedural complications, General disorders and administration site conditions, and Metabolism and nutrition disorders at the System Organ Class level.

Conclusion

This study offered new perspectives on the monitoring, surveillance, and management of adverse drug reactions related to tirzepatide. The outcomes of severe adverse events and their respective detection signals, along with unexpected significant adverse event signals, are important to consider in efforts to enhance clinical medication safety when using tirzepatide.

Improvement of Theaflavins on Glucose and Lipid Metabolism in Diabetes Mellitus

In diabetes mellitus, disordered glucose and lipid metabolisms precipitate diverse complications, including nonalcoholic fatty liver disease, contributing to a rising global mortality rate. Theaflavins (TFs) can improve disorders of glycolipid metabolism in diabetic patients and reduce various types of damage, including glucotoxicity, lipotoxicity, and other associated secondary adverse effects. TFs exert effects to lower blood glucose and lipids levels, partly by regulating digestive enzyme activities, activation of OATP-MCT pathway and increasing secretion of incretins such as GIP. By the Ca2+-CaMKK ꞵ-AMPK and PI3K-AKT pathway, TFs promote glucose utilization and inhibit endogenous glucose production. Along with the regulation of energy metabolism by AMPK-SIRT1 pathway, TFs enhance fatty acids oxidation and reduce de novo lipogenesis. As such, the administration of TFs holds significant promise for both the prevention and amelioration of diabetes mellitus.

Liver kinase B1 (LKB1) regulates the epigenetic landscape of mouse pancreatic beta cells

Liver kinase B1 (LKB1/STK11) is an important regulator of pancreatic β-cell identity and function. Elimination of Lkb1 from the β-cell results in improved glucose-stimulated insulin secretion and is accompanied by profound changes in gene expression, including the upregulation of several neuronal genes. The mechanisms through which LKB1 controls gene expression are, at present, poorly understood. Here, we explore the impact of β cell- selective deletion of Lkb1 on chromatin accessibility in mouse pancreatic islets. To characterize the role of LKB1 in the regulation of gene expression at the transcriptional level, we combine these data with a map of islet active transcription start sites and histone marks. We demonstrate that LKB1 elimination from β-cells results in widespread changes in chromatin accessibility, correlating with changes in transcript levels. Changes occurred in hundreds of promoter and enhancer regions, many of which were close to neuronal genes. We reveal that dysregulated enhancers are enriched in binding motifs for transcription factors important for β-cell identity, such as FOXA, MAFA or RFX6 and we identify microRNAs (miRNAs) that are regulated by LKB1 at the transcriptional level. Overall, our study provides important new insights into the epigenetic mechanisms by which LKB1 regulates β-cell identity and function.

In type 2 diabetes, the effectiveness and side effects of GLP-1 RAs vary

SOURCE CITATION

Yao H, Zhang A, Li D, et al. Comparative effectiveness of GLP-1 receptor agonists on glycaemic control, body weight, and lipid profile for type 2 diabetes: systematic review and network meta-analysis. BMJ. 2024;384:e076410. 38286487.

Glucagon-like peptide-1 receptor agonists: new strategies and therapeutic targets to treat atherosclerotic cardiovascular disease

Atherosclerotic cardiovascular disease (ASCVD) is a leading cause of cardiovascular mortality and is increasingly prevalent in our population. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) can safely and effectively lower glucose levels while concurrently managing the full spectrum of ASCVD risk factors and improving patients' long-term prognosis. Several cardiovascular outcome trials (CVOTs) have been carried out to further investigate the cardiovascular benefits of GLP-1RAs. Analyzing data from CVOTs can provide insights into the pathophysiologic mechanisms by which GLP-1RAs are linked to ASCVD and define the use of GLP-1RAs in clinical practice. Here, we discussed various mechanisms hypothesized in previous animal and preclinical human studies, including blockade of the production of adhesion molecules and inflammatory factors, induction of endothelial cells' synthesis of nitric oxide, protection of mitochondrial function and restriction of oxidative stress, suppression of NOD-like receptor thermal protein domain associated protein three inflammasome, reduction of foam cell formation and macrophage inflammation, and amelioration of vascular smooth muscle cell dysfunction, to help explain the cardiovascular benefits of GLP-1RAs in CVOTs. This paper provides an overview of the clinical research, molecular processes, and possible therapeutic applications of GLP-1RAs in ASCVD, while also addressing current limitations in the literature and suggesting future research directions.

Positive Effects of Adiponectin, BDNF, and GLP-1 on Cortical Neurons Counteracting Palmitic Acid Induced Neurotoxicity

The prevalence of metabolic syndrome caused by diets containing excessive fatty acids is increasing worldwide. Patients with metabolic syndrome exhibit abnormal lipid profiles, chronic inflammation, increased levels of saturated fatty acids, impaired insulin sensitivity, excessive fat accumulation, and neuropathological issues such as memory deficits. In particular, palmitic acid (PA) in saturated fatty acids aggravates inflammation, insulin resistance, impaired glucose tolerance, and synaptic failure. Recently, adiponectin, brain-derived neurotrophic factor (BDNF), and glucose-like peptide-1 (GLP-1) have been investigated to find therapeutic solutions for metabolic syndrome, with findings suggesting that they are involved in insulin sensitivity, enhanced lipid profiles, increased neuronal survival, and improved synaptic plasticity. We investigated the effects of adiponectin, BDNF, and GLP-1 on neurite outgrowth, length, and complexity in PA-treated primary cortical neurons using Sholl analysis. Our findings demonstrate the therapeutic potential of adiponectin, BDNF, and GLP-1 in enhancing synaptic plasticity within brains affected by metabolic imbalance. We underscore the need for additional research into the mechanisms by which adiponectin, BDNF, and GLP-1 influence neural complexity in brains with metabolic imbalances.

Duodenal enteroendocrine cells and GIP as treatment targets for obesity and type 2 diabetes

The duodenum is an important source of endocrine and paracrine signals controlling digestion and nutrient disposition, notably including the main incretin hormone glucose-dependent insulinotropic polypeptide (GIP). Bariatric procedures that prevent nutrients from contact with the duodenal mucosa are particularly effective interventions to reduce body weight and improve glycaemic control in obesity and type 2 diabetes. These procedures take advantage of increased nutrient delivery to more distal regions of the intestine which enhances secretion of the other incretin hormone glucagon-like peptide-1 (GLP-1). Preclinical experiments have shown that either an increase or a decrease in the secretion or action of GIP can decrease body weight and blood glucose in obesity and non-insulin dependent hyperglycaemia, but clinical studies involving administration of GIP have been inconclusive. However, a synthetic dual agonist peptide (tirzepatide) that exerts agonism at receptors for GIP and GLP-1 has produced marked weight-lowering and glucose-lowering effects in people with obesity and type 2 diabetes. This appears to result from chronic biased agonism in which the novel conformation of the peptide triggers enhanced signalling by the GLP-1 receptor through reduced internalisation while reducing signalling by the GIP receptor directly or via functional antagonism through increased internalisation and degradation.

Glucagon-Like Peptide-1 Based Therapies: A New Horizon in Obesity Management

Obesity is a significant risk factor for health issues like type 2 diabetes and cardiovascular disease. It often proves resistant to traditional lifestyle interventions, prompting a need for more precise therapeutic strategies. This has led to a focus on signaling pathways and neuroendocrine mechanisms to develop targeted obesity treatments. Recent developments in obesity management have been revolutionized by introducing novel glucagon-like peptide-1 (GLP-1) based drugs, such as semaglutide and tirzepatide. These drugs are part of an emerging class of nutrient-stimulated hormone-based therapeutics, acting as incretin mimetics to target G-protein-coupled receptors like GLP-1, glucose-dependent insulinotropic polypeptide (GIP), and glucagon. These receptors are vital in regulating body fat and energy balance. The development of multiagonists, including GLP-1-glucagon and GIP-GLP-1-glucagon receptor agonists, especially with the potential for glucagon receptor activation, marks a significant advancement in the field. This review covers the development and clinical efficacy of various GLP-1-based therapeutics, exploring the challenges and future directions in obesity management.

Immunomodulation through Nutrition Should Be a Key Trend in Type 2 Diabetes Treatment

An organism's ability to function properly depends not solely on its diet but also on the intake of nutrients and non-nutritive bioactive compounds that exert immunomodulatory effects. This principle applies both to healthy individuals and, in particular, to those with concomitant chronic conditions, such as type 2 diabetes. However, the current food industry and the widespread use of highly processed foods often lead to nutritional deficiencies. Numerous studies have confirmed the occurrence of immune system dysfunction in patients with type 2 diabetes. This article elucidates the impact of specific nutrients on the immune system function, which maintains homeostasis of the organism, with a particular emphasis on type 2 diabetes. The role of macronutrients, micronutrients, vitamins, and selected substances, such as omega-3 fatty acids, coenzyme Q10, and alpha-lipoic acid, was taken into consideration, which outlined the minimum range of tests that ought to be performed on patients in order to either directly or indirectly determine the severity of malnutrition in this group of patients.

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.

Secretion of glucagon, GLP-1 and GIP may be affected by circadian rhythm in healthy males

BACKGROUND

Glucagon is secreted from pancreatic alpha cells in response to low blood glucose and increases hepatic glucose production. Furthermore, glucagon enhances hepatic protein and lipid metabolism during a mixed meal. Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are secreted from gut endocrine cells during meals and control glucose homeostasis by potentiating insulin secretion and inhibiting food intake. Both glucose homeostasis and food intake have been reported to be affected by circadian rhythms and vice versa. In this study, we investigated whether the secretion of glucagon, GLP-1 and GIP was affected by circadian rhythms.

METHODS

A total of 24 healthy men with regular sleep schedules were examined for 24 h at the hospital ward with 15 h of wakefulness and 9 h of sleep. Food intake was standardized, and blood samples were obtained every third hour. Plasma concentrations of glucagon, GLP-1 and GIP were measured, and data were analyzed by rhythmometric statistical methods. Available data on plasma glucose and plasma C-peptide were also included.

RESULTS

Plasma concentrations of glucagon, GLP-1, GIP, C-peptide and glucose fluctuated with a diurnal 24-h rhythm, with the highest levels during the day and the lowest levels during the night: glucagon (p < 0.0001, peak time 18:26 h), GLP-1 (p < 0.0001, peak time 17:28 h), GIP (p < 0.0001, peak time 18:01 h), C-peptide (p < 0.0001, peak time 17.59 h), and glucose (p < 0.0001, peak time 23:26 h). As expected, we found significant correlations between plasma concentrations of C-peptide and GLP-1 and GIP but did not find correlations between glucose concentrations and concentrations of glucagon, GLP-1 and GIP.

CONCLUSIONS

Our results demonstrate that under meal conditions that are similar to that of many free-living individuals, plasma concentrations of glucagon, GLP-1 and GIP were observed to be higher during daytime and evening than overnight. These findings underpin disturbed circadian rhythm as a potential risk factor for diabetes and obesity.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT06166368. Registered 12 December 2023.

Recent advances in peptide-based therapies for obesity and type 2 diabetes

Options for the treatment of type 2 diabetes mellitus (T2DM) and obesity have recently been expanded by the results of several large clinical trials with incretin-based peptide therapies. Most of these studies have been conducted with the glucagon-like peptide-1 (GLP-1) receptor agonist semaglutide, which is available as a once weekly subcutaneous injection and once daily tablet, and the once weekly injected dual agonist tirzepatide, which interacts with receptors for GLP-1 and glucose-dependent insulinotropic polypeptide (GIP). In individuals with T2DM these therapies have achieved reductions of glycated haemoglobin (HbA1c) by > 2% and lowered body weight by > 10%. In some studies, these agents tested in non-diabetic, obese individuals at much higher doses have lowered body weight by > 15%. Emerging evidence suggests these agents can also offer cardio-protective and potentially reno-protective effects. Other incretin-based peptide therapies in early clinical development, notably a triple GLP-1/GIP/glucagon receptor agonist (retatrutide) and a combination of semaglutide with the amylin analogue cagrilintide (CagriSema), have shown strong efficacy. Although incretin therapies can incur adverse gastrointestinal effects these are for most patients mild-to-moderate and transient but result in cessation of treatment in some cases. Thus, the efficacy of new incretin-based peptide therapies is enhancing the opportunity to control body weight and blood glucose and improve the treatment of T2DM and obesity.

Association of GLP-1 secretion with parameters of glycemic control in women after gestational diabetes mellitus

INTRODUCTION

Women with a history of gestational diabetes mellitus (GDM) are at high risk of developing type 2 diabetes, while the exact mechanisms underlying its pathophysiology are still unclear. We investigated the association of glucagon-like peptide-1 (GLP-1) response to oral glucose with parameters of glycemic control in women with previous GDM in the prospective PPSDiab (Prediction, Prevention, and Subclassification of Type 2 Diabetes) study.

RESEARCH DESIGN AND METHODS

Glucose metabolism parameters and GLP-1 secretion were analyzed during oral glucose tolerance test (OGTT) in women with previous GDM (n=129) and women with a history of normal glucose tolerance (n=67) during pregnancy (controls). First- and second-phase insulin and GLP-1 secretion in relation to plasma glucose (PG) levels were assessed, and development of pre-diabetes was analyzed after 5-year follow-up among women with previous GDM and a normal glycemic state at baseline (n=58).

RESULTS

The area under the curve (AUC during the OGTT 0-120 min) of PG and insulin but not GLP-1 differed significantly between post-GDM women and controls. However, women with previous GDM had a significantly decreased GLP-1 response in relation to PG and plasma insulin during the second phase of the OGTT. After a follow-up of 5 years, 19.0% post-GDM women with a normal glycemic state at the baseline visit developed abnormal glucose metabolism. The total, first- and second-phase AUC GLP-1/PG and GLP-1/insulin ratios were not associated with development of abnormal glucose tolerance.

CONCLUSIONS

Women with previous GDM showed a reduced GLP-1 response in relation to PG and insulin concentrations indicating early abnormalities in glucose metabolism. However, the altered GLP-1 response to oral glucose did not predict progression to pre-diabetes and type 2 diabetes in the first 5 years after GDM.

Effect of tirzepatide on glycaemic control and weight loss compared with other glucagon-like peptide-1 receptor agonists in Japanese patients with type 2 diabetes mellitus

AIM

To compare the therapeutic effects of glucose-dependent insulinotropic polypeptide (GIP)/ glucagon-like peptide-1 receptor agonists (GLP-1RAs) or GLP-1RAs in Japanese patients with type 2 diabetes (T2D).

MATERIALS AND METHODS

We systematically searched PubMed, MEDLINE, EMBASE, and the Cochrane Library up to July 2023. Randomized controlled trials (RCTs) that compared GLP-1RAs or GIP/GLP-1RAs in Japanese patients with T2D were selected. A network meta-analysis was conducted to indirectly compare the treatments, focusing on efficacy in reducing glycated haemoglobin (HbA1c) levels and body weight (BW).

RESULTS

A total of 18 RCTs were included in this analysis. Tirzepatide 15 mg showed the most significant reduction in HbA1c levels and BW compared with subcutaneous semaglutide 1.0 mg and oral semaglutide 14 mg (HbA1c: mean difference [95% confidence interval] -0.52 [-0.96; -0.08] and - 1.23 [-1.64; -0.81]; BW: -5.07 [-8.28; -1.86] and -6.84 [-8.97; -4.71], respectively). Subcutaneous semaglutide showed a superior reduction in HbA1c compared with oral semaglutide. Both subcutaneous and oral semaglutide were more effective than conventional GLP-1RAs, such as dulaglutide, liraglutide and lixisenatide.

CONCLUSIONS

Among Japanese patients with T2D, tirzepatide showed the greatest effectiveness in reducing HbA1c levels and inducing weight loss. The study provides evidence to guide GLP-1RA treatment strategies in Japanese patients with T2D.

The Anti-Diabetic Potential of Baicalin: Evidence from Rodent Studies

Baicalin is a biologically active flavonoid compound that benefits the organism in various pathological conditions. Rodent studies have shown that this compound effectively alleviates diabetes-related disturbances in models of type 1 and type 2 diabetes. Baicalin supplementation limited hyperglycemia and improved insulin sensitivity. The anti-diabetic effects of baicalin covered the main insulin-sensitive tissues, i.e., the skeletal muscle, the adipose tissue, and the liver. In the muscle tissue, baicalin limited lipid accumulation and improved glucose transport. Baicalin therapy was associated with diminished adipose tissue content and increased mitochondrial biogenesis. Hepatic lipid accumulation and glucose output were also decreased as a result of baicalin supplementation. The molecular mechanism of the anti-diabetic action of this compound is pleiotropic and is associated with changes in the expression/action of pivotal enzymes and signaling molecules. Baicalin positively affected, among others, the tissue insulin receptor, glucose transporter, AMP-activated protein kinase, protein kinase B, carnitine palmitoyltransferase, acetyl-CoA carboxylase, and fatty acid synthase. Moreover, this compound ameliorated diabetes-related oxidative and inflammatory stress and reduced epigenetic modifications. Importantly, baicalin supplementation at the effective doses did not induce any side effects. Results of rodent studies imply that baicalin may be tested as an anti-diabetic agent in humans.

Real-World Retrospective Study into the Effects of Oral Semaglutide (As a Switchover or Add-On Therapy) in Type 2 Diabetes

(1) Background: Oral semaglutide represents the first oral GLP-1 RA approved for the treatment of type 2 diabetes mellitus (T2DM). This real-world retrospective study aimed at evaluating its effectiveness and tolerability in the treatment of patients with T2DM when patients switched from a glucose-lowering agent to it and when it was added to the usual therapy. (2) Methods: Adult patients with T2DM taking oral semaglutide and followed in the ASUGI Diabetes Center were identified with the use of electronic medical records between October 2022 and May 2023. (3) Results: A total of 129 patients were recruited. The median follow-up was 6 months. Be it as a switchover or as an add-on therapy, oral semaglutide significantly reduced HbA1c and BMI. Switching from DPPIV inhibitors to oral semaglutide was associated with a significant reduction in HbA1c and BMI, switching from SGLT2 inhibitors was associated with a significant reduction in HbA1c, and switching from sulphonylureas was associated with a significant reduction in BMI. The median HbA1c change was associated with baseline HbA1c. SBP significantly decreased in the add-on group. Oral semaglutide was well tolerated. (4) Conclusions: This study shows that in the real-world setting, oral semaglutide is effective and safe as a switchover or as an add-on therapy for the treatment of T2DM.

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.