Incretin hormones: Their role in health and disease

Liraglutide alleviates high-fat diet-induced kidney injury in mice by regulating the CaMKKβ/AMPK pathway

OBJECTIVE

Liraglutide, a glucagon-like peptide-1 receptor agonist, has been shown to regulate blood sugar and control body weight, but its ability to treat obesity-related nephropathy has been poorly studied. Therefore, this study was designed to observe the characteristics and potential mechanism of liraglutide against obesity-related kidney disease.

METHODS

Thirty-six C57BL/6J male mice were randomly divided into six groups (n = 6 per group). Obesity-related nephropathy was induced in mice by continuous feeding of high-fat diet (HFD) for 12 weeks. After 12 weeks, liraglutide (0.6 mg/kg) and AMP-activated protein kinase (AMPK) agonists bortezomib (200 μg/kg) were injected for 12 weeks, respectively. Enzyme-linked immunosorbent assay was employed to detect the levels of total cholesterol, triglycerides, low-density lipoprotein cholesterol, blood urea nitrogen, creatinine in serum, as well as urinary protein in urine. Besides, hematoxylin-eosin staining and periodic acid-Schiff staining were used to observe the pathological changes of kidney tissue; immunohistochemistry, western blot, and real-time quantitative PCR to assess the calmodulin-dependent protein kinase kinase beta (CaMKKβ)/AMPK signaling pathway activation.

RESULTS

Liraglutide significantly reduced serum lipid loading, improved kidney function, and relieved kidney histopathological damage and glycogen deposition in the mouse model of obesity-related kidney disease induced by HFD. In addition, liraglutide also significantly inhibited the CaMKKβ/AMPK signaling pathway in kidney tissue of HFD-induced mice. However, bortezomib partially reversed the therapeutic effect of liraglutide on HDF-induced nephropathy in mice.

CONCLUSIONS

Liraglutide has a therapeutic effect on obesity-related kidney disease, and such an effect may be achieved by inhibiting the CaMKKβ/AMPK signaling pathway in kidney tissue.

Silibinin, a commonly used therapeutic agent for non-alcohol fatty liver disease, functions through upregulating intestinal expression of fibroblast growth factor 15/19

BACKGROUND AND PURPOSE

Silibinin is used to treat non-alcohol fatty liver disease (NAFLD) despite having rapid liver metabolism. Therefore, we investigated the role of the intestine in silibinin mechanism of action.

EXPERIMENTAL APPROACH

NAFLD mice model was established by feeding them with a high-fat diet (HFD). Liver pathological were examined using H&E and oil red O staining. Tissue distribution of silibinin was detected by LC-MS/MS. SiRNA was employed for gene silencing and plasmid was used for gene overexpression. ChIP-qPCR assay was performed to detect the levels of histone acetylation. Recombinant adeno-associated virus 9-short hairpin-fibroblast growth factor (FGF)-15 and -farnesoid X receptor (FXR; NR1H4) were used to knockdown expression of FGF-15 and FXR.

KEY RESULTS

Oral silibinin significantly reversed NAFLD in mice, although liver concentration was insufficient for reduction of lipid accumulation in hepatocytes. Among endogenous factors capable of reversing NAFLD, the expression of Fgf-15 was selectively up-regulated by silibinin in ileum and colon of mice. When intestinal expression of Fgf-15 was knocked down, protection of silibinin against lipid accumulation and injury of livers nearly disappeared. Silibinin could reduce activity of histone deacetylase 2 (HDAC2), enhance histone acetylation in the promoter region of FXR and consequently increase intestinal expression of FGF-15/19.

CONCLUSION AND IMPLICATIONS

Oral silibinin selectively promotes expression of FGF-15/19 in ileum by enhancing transcription of FXR via reduction of HDAC2 activity, and FGF-15/19 enters into circulation to exert anti-NAFLD action. As the site of action is the intestine this would explain the discrepancy between pharmacodynamics and pharmacokinetics of silibinin.

Incretin-Based Weight Loss Pharmacotherapy: Can Resistance Exercise Optimize Changes in Body Composition?

This narrative review highlights the degree to which new antiobesity medications based on gut-derived nutrient-stimulated hormones (incretins) cause loss of lean mass, and the importance of resistance exercise to preserve muscle. Glucagon-like peptide 1 receptor agonists (GLP-1RA) induce substantial weight loss in randomized trials, effects that may be enhanced in combination with glucose-dependent insulinotropic polypeptide (GIP) receptor agonists. Liraglutide and semaglutide (GLP-1RA), tirzepatide (GLP-1 and GIP receptor dual agonist), and retatrutide (GLP-1, GIP, and glucagon receptor triple agonist) are peptides with incretin agonist activity that induce ∼15-24% weight loss in adults with overweight and obesity, alongside beneficial impacts on blood pressure, cholesterol, blood glucose, and insulin. However, these agents also cause rapid and significant loss of lean mass (∼10% or ∼6 kg), comparable to a decade or more of aging. Maintaining muscle mass and function as humans age is crucial to avoiding sarcopenia and frailty, which are strongly linked to morbidity and mortality. Studies indicate that supervised resistance exercise training interventions with a duration >10 weeks can elicit large increases in lean mass (∼3 kg) and strength (∼25%) in men and women. After a low-calorie diet, combining aerobic exercise with liraglutide improved weight loss maintenance compared with either alone. Retaining lean mass during incretin therapy could blunt body weight (and fat) regain on cessation of weight loss pharmacotherapy. We propose that tailored resistance exercise training be recommended as an adjunct to incretin therapy to optimize changes in body composition by preserving lean mass while achieving fat loss.

A comprehensive review to assess the potential, health benefits and complications of fucoidan for developing as functional ingredient and nutraceutical

Polysaccharides from seaweeds or macroalgae are garnering significant interest from pharmaceutical and food industries due to their bioactivities and promising therapeutic effects. Among the diverse agal polysaccharides, fucoidan is a well-documented and stands out as a well-researched sulphated heteropolysaccharide found in brown seaweeds. It primarily consists of l-fucose and sulfate ester groups, along with other monosaccharides like xylose, mannose, uronic acid, rhamnose, arabinose, and galactose. Recent scientific investigations have unveiled the formidable inhibitory prowess of fucoidan against SARS-CoV-2, offering a promising avenue for therapeutic intervention in our current landscape. Moreover, fucoidan has demonstrated remarkable abilities in safeguarding the gastrointestinal tract, regulating angiogenesis, mitigating metabolic syndrome, and fortifying bone health. Despite the abundance of studies underscoring fucoidan's potential as a vital component sourced from nature, its exploitation remains constrained by inherent limitations. Thus, the primary objective of this article is to furnish a comprehensive discourse on the structural attributes, health-enhancing properties, safety parameters, and potential toxicity associated with fucoidan. Furthermore, the discourse extends to elucidating the practical applications and developmental prospects of fucoidan as a cornerstone in the realm of functional foods and nutraceuticals.

Glucagon-like peptide-1 receptor agonist-based agents and weight loss composition: Filling the gaps

Excess adiposity is at the root of type 2 diabetes (T2D). Glucagon-like peptide-1 receptor agonists (GLP-1RAs) have emerged as first-line treatments for T2D based on significant weight loss results. The composition of weight loss using most diets consists of <25% fat-free mass (FFM) loss, with the remainder from fat stores. Higher amounts of weight loss (achieved with metabolic bariatric surgery) result in greater reductions in FFM. Our aim was to assess the impact that GLP-1RA-based treatments have on FFM. We analysed studies that reported changes in FFM with the following agents: exenatide, liraglutide, semaglutide, and the dual incretin receptor agonist tirzepatide. We performed an analysis of various weight loss interventions to provide a reference for expected changes in FFM. We evaluated studies using dual-energy X-ray absorptiometry (DXA) for measuring FFM (a crude surrogate for skeletal muscle). In evaluating the composition of weight loss, the percentage lost as fat-free mass (%FFML) was equal to ΔFFM/total weight change. The %FFML using GLP-1RA-based agents was between 20% and 40%. In the 28 clinical trials evaluated, the proportion of FFM loss was highly variable, but the majority reported %FFML exceeding 25%. Our review was limited to small substudies and the use of DXA, which does not measure skeletal muscle mass directly. Since FFM contains a variable amount of muscle (approximately 55%), this indirect measure may explain the heterogeneity in the data. Assessing quantity and quality of skeletal muscle using advanced imaging (magnetic resonance imaging) with functional testing will help fill the gaps in our current understanding.

Tirzepatide, a dual glucose-dependent insulinotropic polypeptide/glucagon-like peptide 1 receptor agonist, exhibits favourable effects on pancreatic β-cells and hepatic steatosis in obese type 2 diabetic db/db mice

AIM

Tirzepatide, a dual agonist of glucagon-like peptide receptor and glucose-dependent insulinotropic polypeptide receptor, is expected to exhibit high clinical efficacy in obese type 2 diabetic patients. We evaluated the effects of tirzepatide on pancreatic β-cells and the liver, an insulin-target organ, in a mouse model of obese type 2 diabetes mellitus.

MATERIALS AND METHODS

Obese type 2 diabetic db/db mice (BKS.Cg-/+ Leprdb/+ Leprdb/Jcl*) were used in this study. Starting at 7 weeks of age, mice were treated with tirzepatide (30 nmol/kg, subcutaneous injection twice a week) or semaglutide (200 nmol/kg, subcutaneous injection twice a week). The control group received phosphate-buffered saline (40-50 μL/subcutaneous injection twice a week). After 4 weeks of drug administration, pancreatic β-cells and the liver were removed and examined.

RESULTS

Compared to the control group, blood glucose and body weight were significantly reduced in the group that received either tirzepatide or semaglutide (p < 0.001 and p < 0.05, respectively). Fasting insulin was significantly higher in the semaglutide and tirzepatide groups compared to the control group (p < 0.001). β-Cell mass and quality of insulin granules in β-cells similarly increased in the semaglutide and tirzepatide groups compared to the control group (p < 0.05 and p < 0.001, respectively). The fat staining area in the liver in oil red O staining and the liver-spleen ratio in computed tomography showed improvement only in the tirzepatide group (p < 0.001 and p < 0.005, respectively). Liver macrophage M1/M2 ratio similarly improved with semaglutide and tirzepatide (p < 0.05).

CONCLUSION

Tirzepatide and semaglutide exhibited similar potent glucose-lowering effects. At concentrations used in the present experiments, tirzepatide exhibited more beneficial effects on β-cell-related gene expression, insulin granule count and glucose-stimulated insulin secretion compared to semaglutide. In addition, tirzepatide exhibited a stronger favourable effect on hepatic fat deposition and improved inflammation in the liver. This is the first report showing that tirzepatide, a novel diabetes drug, exhibits a superior effect on pancreatic β-cells and the liver of obese type 2 diabetic mice.

Probiotic therapy as a promising strategy for gestational diabetes mellitus management

INTRODUCTION

Gestational diabetes mellitus (GDM) has become the most common pregnancy medical complication, and its prevalence has increased in recent years. The GDM treatment primarily relies on adopting healthy eating habits, physical exercise, and insulin therapy. However, using probiotics to modulate the gut microbiota has been the subject of clinical trials as a promising therapeutic strategy for GDM management.

AREAS COVERED

Due to the adverse effects of gut dysbiosis in women with GDM, strategies targeting the gut microbiota to mitigate hyperglycemia, low-grade inflammation, and adverse pregnancy outcomes have been explored. Probiotic supplementation may improve glucose metabolism, lipid profile, oxidative stress, inflammation, and blood pressure in women with GDM. Furthermore, decreased fasting blood glucose, insulin resistance, and inflammatory markers, such as TNF-α and CRP, as well as increased total antioxidant capacity, lipid profile modulation, and improved blood pressure in women with GDM, are some of the important results reported in the available literature.

EXPERT OPINION

To fill the knowledge gap, further studies are needed focusing on modulating gut microbiota composition and metabolic activity and their systemic repercussions in GDM.

Repurposing metabolic regulators: antidiabetic drugs as anticancer agents

Drug repurposing in cancer taps into the capabilities of existing drugs, initially designed for other ailments, as potential cancer treatments. It offers several advantages over traditional drug discovery, including reduced costs, reduced development timelines, and a lower risk of adverse effects. However, not all drug classes align seamlessly with a patient's condition or long-term usage. Hence, repurposing of chronically used drugs presents a more attractive option. On the other hand, metabolic reprogramming being an important hallmark of cancer paves the metabolic regulators as possible cancer therapeutics. This review emphasizes the importance and offers current insights into the repurposing of antidiabetic drugs, including metformin, sulfonylureas, sodium-glucose cotransporter 2 (SGLT2) inhibitors, dipeptidyl peptidase 4 (DPP-4) inhibitors, glucagon-like peptide-1 receptor agonists (GLP-1RAs), thiazolidinediones (TZD), and α-glucosidase inhibitors, against various types of cancers. Antidiabetic drugs, regulating metabolic pathways have gained considerable attention in cancer research. The literature reveals a complex relationship between antidiabetic drugs and cancer risk. Among the antidiabetic drugs, metformin may possess anti-cancer properties, potentially reducing cancer cell proliferation, inducing apoptosis, and enhancing cancer cell sensitivity to chemotherapy. However, other antidiabetic drugs have revealed heterogeneous responses. Sulfonylureas and TZDs have not demonstrated consistent anti-cancer activity, while SGLT2 inhibitors and DPP-4 inhibitors have shown some potential benefits. GLP-1RAs have raised concerns due to possible associations with an increased risk of certain cancers. This review highlights that further research is warranted to elucidate the mechanisms underlying the potential anti-cancer effects of these drugs and to establish their efficacy and safety in clinical settings.

Therapeutic Potential of Glucagon-like Peptide-1 Receptor Agonists in Obstructive Sleep Apnea Syndrome Management: A Narrative Review

Background: Obstructive Sleep Apnea (OSA) is a prevalent disorder characterized by repetitive upper airway obstructions during sleep, leading to intermittent hypoxia and sleep fragmentation. Current treatments, particularly Continuous Positive Airway Pressure (CPAP), face adherence challenges, necessitating novel therapeutic approaches. Methods: This review explores the potential of Glucagon-like Peptide-1 receptor agonists (GLP-1RA), commonly used for type 2 diabetes and obesity, in managing OSA. GLP-1RA promotes weight loss, enhances insulin sensitivity, and exhibits anti-inflammatory and neuroprotective properties, potentially addressing key pathophysiological aspects of OSA. Results: Emerging evidence suggests that these agents may reduce OSA severity by decreasing upper airway fat deposition and improving respiratory control. Clinical trials have demonstrated significant reductions in the Apnea-Hypopnea Index (AHI) and improvements in sleep quality with GLP-1 therapy. Conclusions: Future research should focus on elucidating the mechanisms underlying GLP-1 effects on OSAS, optimizing combination therapies, and identifying patient subgroups that may benefit the most. Integrating GLP-1RA into OSAS management could revolutionize treatment by addressing both the metabolic and respiratory components of the disorder, ultimately enhancing patient outcomes.

Yoyo Dieting, Post-Obesity Weight Loss, and Their Relationship with Gut Health

Excessive body weight is associated with many chronic metabolic diseases and weight loss, so far, remains the gold standard treatment. However, despite tremendous efforts exploring optimal treatments for obesity, many individuals find losing weight and maintaining a healthy body weight difficult. Weight loss is often not sustainable resulting in weight regain and subsequent efforts to lose weight. This cyclic pattern of weight loss and regain is termed "yoyo dieting" and predisposes individuals to obesity and metabolic comorbidities. How yoyo dieting might worsen obesity complications during the weight recurrence phase remains unclear. In particular, there is limited data on the role of the gut microbiome in yoyo dieting. Gut health distress, especially gut inflammation and microbiome perturbation, is strongly associated with metabolic dysfunction and disturbance of energy homeostasis in obesity. In this review, we summarise current evidence of the crosstalk between the gastrointestinal system and energy balance, and the effects of yoyo dieting on gut inflammation and gut microbiota reshaping. Finally, we focus on the potential effects of post-dieting weight loss in improving gut health and identify current knowledge gaps within the field, including gut-derived peptide hormones and their potential suitability as targets to combat weight regain, and how yoyo dieting and associated changes in the microbiome affect the gut barrier and the enteric nervous system, which largely remain to be determined.

Glucagon-like peptide-1 receptor: mechanisms and advances in therapy

The glucagon-like peptide-1 (GLP-1) receptor, known as GLP-1R, is a vital component of the G protein-coupled receptor (GPCR) family and is found primarily on the surfaces of various cell types within the human body. This receptor specifically interacts with GLP-1, a key hormone that plays an integral role in regulating blood glucose levels, lipid metabolism, and several other crucial biological functions. In recent years, GLP-1 medications have become a focal point in the medical community due to their innovative treatment mechanisms, significant therapeutic efficacy, and broad development prospects. This article thoroughly traces the developmental milestones of GLP-1 drugs, from their initial discovery to their clinical application, detailing the evolution of diverse GLP-1 medications along with their distinct pharmacological properties. Additionally, this paper explores the potential applications of GLP-1 receptor agonists (GLP-1RAs) in fields such as neuroprotection, anti-infection measures, the reduction of various types of inflammation, and the enhancement of cardiovascular function. It provides an in-depth assessment of the effectiveness of GLP-1RAs across multiple body systems-including the nervous, cardiovascular, musculoskeletal, and digestive systems. This includes integrating the latest clinical trial data and delving into potential signaling pathways and pharmacological mechanisms. The primary goal of this article is to emphasize the extensive benefits of using GLP-1RAs in treating a broad spectrum of diseases, such as obesity, cardiovascular diseases, non-alcoholic fatty liver disease (NAFLD), neurodegenerative diseases, musculoskeletal inflammation, and various forms of cancer. The ongoing development of new indications for GLP-1 drugs offers promising prospects for further expanding therapeutic interventions, showcasing their significant potential in the medical field.

Glucagon-like peptide-1 receptor agonists and risk of gastrointestinal cancers: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are commonly used for glucose lowering and weight-loss. However, their association with gastrointestinal cancer remains uncertain. This meta-analysis assesses the risk of gastrointestinal cancer in patients treated with GLP-1 RAs.

METHODS

We searched Medline/PubMed, Embase, and Scopus databases from inception to November 15, 2023, for randomized controlled trials (RCTs) with at least 24 weeks of safety follow-up. Pooled risk ratios (RRs) were calculated using fixed- and random-effect models. Risk of bias was assessed using the revised Cochrane risk-of-bias tool, and certainty of evidence was determined using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework.

RESULTS

We included 90 RCTs with 124,791 participants, with an average follow-up of 3.1 years per participant. No significant association was found between GLP-1 RAs and the risk of any gastrointestinal cancer (RRrandom=0.99, 95 % CI: 0.86-1.13), or site-specific gastrointestinal cancers including biliary tract (RR=0.98, 0.54-1.78), colorectal (RR=1.13, 0.92-1.39), gallbladder (RR=1.32, 0.43-4.00), gastric (RR=0.88, 0.58-1.33), hepatic (RR=0.79, 0.51-1.21), oesophageal (RR=0.70, 0.38-1.28), pancreatic (RR=1.05, 0.77-1.43), and small intestine cancer (RR=0.78, 0.20-3.04). The corresponding absolute risk differences excluded important impacts on risk. Additional analyses, limited to placebo-controlled trials, high-dose studies, or those with a follow-up duration of ≥5 years, confirmed these findings. Risk of bias was generally low and the certainty of evidence was high for all outcomes.

CONCLUSIONS

This meta-analysis found no significant impact of GLP-1 RAs on gastrointestinal cancer risk. Long-term safety monitoring of these agents remains important.

SYSTEMATIC REVIEW REGISTRATION

CRD42023476762.

Curbing the Obesity Epidemic: Should GLP-1 Receptor Agonists Be the Standard of Care for Obesity?

PURPOSE OF REVIEW

This article summarizes the medical management of obesity with an emphasis on incretin-based therapeutics that target the neuro-hormonal basis of obesity.

RECENT FINDINGS

Medications that mimic the effect of incretins, a group of peptide hormones released in response to nutrient intake that regulate appetite, result in potent and durable weight loss. Glucagon-like peptide 1 (GLP-1) agonists and glucose-dependent insulinotropic polypeptide (GIP) agonists such as semaglutide and tirzepatide are approved by the United States Food and Drug Administration (FDA) for the management of obesity. The SELECT trial demonstrated that semaglutide led to a reduction in major adverse cardiovascular events in patients without diabetes who were either overweight and had preexisting cardiovascular disease or obese.

SUMMARY

The treatment of obesity is critical to prevent the progression of cardiovascular-kidney-metabolic syndrome. Incretin-based therapies offer remarkable weight loss and reduce major cardiovascular adverse events.

Metabolic and Aging Influence on Anticancer Immunity in Oral Cancer

The average age and obesity prevalence are increasing globally. Both aging and metabolic disease burden increase the risk of oral squamous cell carcinoma (OSCC) through profound effects on the immunological and metabolic characteristics within the OSCC tumor microenvironment. While the mechanisms that link aging and obesity to OSCC remain unclear, there is evidence that the antitumor responses are diminished in both conditions. Remarkably, however, immune checkpoint blockade, a form of cancer immunotherapy, remains intact despite the enhanced immunosuppressive tumor microenvironment in the context of either aging or obesity. Herein, we review the current knowledge of how aging and systemic metabolic changes affect antitumor immunity with an emphasis on the role of tumor-associated macrophages that greatly contribute to tumor immunosuppression. Key aspects discussed include the mechanisms of angiogenesis, cytokine release, phagocytosis attenuation, and immune cell recruitment during obesity and aging that create an immune-suppressive tumor microenvironment by recruitment and repolarization of tumor-associated macrophages. Through a deeper appreciation of these mechanisms, the development of novel therapeutic approaches to control OSCC will provide more refined management of the tumor microenvironment in the context of aging and obesity.

Differentiating monogenic and syndromic obesities from polygenic obesity: Assessment, diagnosis, and management

Background

Obesity is a multifactorial neurohormonal disease that results from dysfunction within energy regulation pathways and is associated with increased morbidity, mortality, and reduced quality of life. The most common form is polygenic obesity, which results from interactions between multiple gene variants and environmental factors. Highly penetrant monogenic and syndromic obesities result from rare genetic variants with minimal environmental influence and can be differentiated from polygenic obesity depending on key symptoms, including hyperphagia; early-onset, severe obesity; and suboptimal responses to nontargeted therapies. Timely diagnosis of monogenic or syndromic obesity is critical to inform management strategies and reduce disease burden. We outline the physiology of weight regulation, role of genetics in obesity, and differentiating characteristics between polygenic and rare genetic obesity to facilitate diagnosis and transition toward targeted therapies.

Methods

In this narrative review, we focused on case reports, case studies, and natural history studies of patients with monogenic and syndromic obesities and clinical trials examining the efficacy, safety, and quality of life impact of nontargeted and targeted therapies in these populations. We also provide comprehensive algorithms for diagnosis of patients with suspected rare genetic causes of obesity.

Results

Patients with monogenic and syndromic obesities commonly present with hyperphagia (ie, pathologic, insatiable hunger) and early-onset, severe obesity, and the presence of hallmark characteristics can inform genetic testing and diagnostic approach. Following diagnosis, specialized care teams can address complex symptoms, and hyperphagia is managed behaviorally. Various pharmacotherapies show promise in these patient populations, including setmelanotide and glucagon-like peptide-1 receptor agonists.

Conclusion

Understanding the pathophysiology and differentiating characteristics of monogenic and syndromic obesities can facilitate diagnosis and management and has led to development of targeted pharmacotherapies with demonstrated efficacy for reducing body weight and hunger in the affected populations.

Randomised comparison of intravenous and subcutaneous routes of glucagon-like peptide-1 administration for lowering plasma glucose in hyperglycaemic subjects with type 2 diabetes

AIM

To perform a direct, double-blind, randomised, crossover comparison of subcutaneous and intravenous glucagon-like peptide-1 (GLP-1) in hyperglycaemic subjects with type 2 diabetes naïve to GLP-1-based therapy.

MATERIALS AND METHODS

Ten fasted, hyperglycaemic subjects (1 female, age 63 ± 10 years [mean ± SD], glycated haemoglobin 73.5 ± 22.0 mmol/mol [8.9% ± 2.0%], both mean ± SD) received subcutaneous GLP-1 and intravenous saline, or intravenous GLP-1 and subcutaneous saline. Infusion rates were doubled every 120 min (1.2, 2.4, 4.8 and 9.6 pmol·kg-1·min-1 for subcutaneous, and 0.3, 0.6, 1.2 and 2.4 pmol·kg-1·min-1 for intravenous). Plasma glucose, total and intact GLP-1, insulin, C-peptide, glucagon and gastrointestinal symptoms were evaluated over 8 h. The results are presented as mean ± SEM.

RESULTS

Plasma glucose decreased more with intravenous (by ~8.0 mmol/L [144 mg/dL]) than subcutaneous GLP-1 (by ~5.6 mmol/L [100 mg/dL]; p < 0.001). Plasma GLP-1 increased dose-dependently, but more with intravenous than subcutaneous for both total (∆max 154.2 ± 3.9 pmol/L vs. 85.1 ± 3.8 pmol/L; p < 0.001), and intact GLP-1 (∆max 44.2 ± 2.2 pmol/L vs. 12.8 ± 2.2 pmol/L; p < 0.001). Total and intact GLP-1 clearance was higher for subcutaneous than intravenous GLP-1 (p < 0.001 and p = 0.002, respectively). The increase in insulin secretion was greater, and glucagon was suppressed more with intravenous GLP-1 (p < 0.05 each). Gastrointestinal symptoms did not differ (p > 0.05 each).

CONCLUSIONS

Subcutaneous GLP-1 administration is much less efficient than intravenous GLP-1 in lowering fasting plasma glucose, with less stimulation of insulin and suppression of glucagon, and much less bioavailability, even at fourfold higher infusion rates.

Glucagon-Like Peptide-1 (GLP-1) Receptor Agonists: Exploring Their Impact on Diabetes, Obesity, and Cardiovascular Health Through a Comprehensive Literature Review

Glucagon-like peptide-1 receptor agonists (GLP-1-RAs) are a novel class of medications promising for treating type 2 diabetes mellitus (T2DM) and obesity-related conditions such as cardiovascular disease (CVD) and non-alcoholic fatty liver disease (NAFLD). This comprehensive literature review examines available research on these medications, focusing on their mechanisms of action, clinical effectiveness, safety profiles, and socioeconomic implications. A comprehensive search was performed using the PubMed, EMBASE, and Cochrane Library databases. Although initially developed for glucose management, these drugs have also demonstrated efficacy in promoting weight loss and reducing the risk of CVD. GLP-1-RAs function similarly to naturally occurring incretins. They stimulate insulin secretion in response to glucose levels, inhibit glucagon release, delay stomach emptying, and generate a sense of fullness via brain pathways. Head-to-head clinical studies have indicated that GLP-1-RAs outperform conventional antidiabetic medicines in terms of glycemic management and weight reduction. According to cardiovascular outcome studies, various drugs in this category have been found to reduce the frequency of severe adverse cardiovascular events. A common side effect is gastrointestinal toxicity, which can be mitigated by gradually increasing the dose. Personalized treatment is likely because the effectiveness, safety, and dose regimens of currently available GLP-1-RAs differ. GLP-1-RAs are a superior choice for patients with T2DM, especially those who already have CVD or require weight-control support. The high cost of these drugs creates hurdles to access and fair healthcare. Current research mainly focuses on increasing therapeutic uses and producing orally delivered medicines with greater potency and bioavailability. Integrating GLP-1-RAs into clinical practice can enhance patient outcomes and reduce the community burden of cardiometabolic disease.

Highly functional duodenal stent with photosensitizers enables photodynamic therapy for metabolic syndrome treatment: Feasibility and safety study in a porcine model

Duodenal mucosal resurfacing (DMR) by thermal ablation of the duodenal mucosa is a minimally invasive endoscopic procedure for controlling metabolic syndrome (MS). However, thermal energy can cause adverse effects due to deep mucosal injury, necessitating an additional mucosal lifting process, which complicate the procedures. Therefore, we aimed to develop a similar procedure using non-thermal photodynamic therapy (PDT) for DMR using a highly functional metal stent covered with photosensitizers (PSs) to minimize the potential risks of thermal ablation injury. We developed a novel PS stent enabling the controlled release of radical oxygen species with specific structures to prevent stent migration and duodenal stricture after ablation and performed an animal study (n = 8) to demonstrate the feasibility and safety of PDT for DMR. The stents were placed for 7 days to prevent duodenal strictures after PDT. To confirm PDT efficacy, we stained for gastric inhibitory polypeptide (GIP) and glucose transporter isoform 1. The PS stents were deployed, and PDT was applied without evidence of duodenal stricture, pancreatitis, or hemorrhage in any of the pigs. Microscopic evaluation indicated apoptosis of the mucosal cells in the irradiated duodenum on days 7 and 14, which recovered after day 28. Immunohistochemistry revealed suppressed GIP expression in the mucosal wall of the irradiated duodenum. Endoscopic PDT for DMR using PS stents could be applied safely in a porcine model and may result in decreased GIP secretion, which is a crucial mechanism in MS treatment. Further clinical studies are required to explore its safety and efficacy in patients with MS.

Tirzepatide: unveiling a new dawn in dual-targeted diabetes and obesity management

INTRODUCTION

Incretin-based therapies have emerged as effective treatments for type 2 diabetes (T2D) and obesity. However, not all patients achieve optimal outcomes with existing treatments, highlighting the need for more effective solutions.

AREAS COVERED

We present a comprehensive evaluation of Tirzepatide (TZP), a novel dual glucose-dependent insulinotropic polypeptide/glucagon-like peptide-1 (GIP/GLP-1) receptor agonist, for managing obesity and T2D. We conducted a systematic search of Cochrane, PubMed, Scopus, and Web of Science databases from inception to April 2024. The focus of the review is on the development and therapeutic potential of TZP, with detailed exploration on pharmacodynamics, pharmacokinetics, clinical efficacy, and safety. Furthermore, it reviews TZP's impacts on glycemic control, weight management, and its potential cardiovascular (CV) benefits.

EXPERT OPINION

TZP represents a significant advancement in the dual-targeted approach to treating T2D and obesity. Its unique mechanism of action offers superior efficacy in reducing glycemic levels and body weight compared to existing therapies. New data suggesting improvements in CV outcomes indicate that TZP could set a new standard in the treatment paradigm. While long-term data on efficacy and safety are still forthcoming, current evidence positions TZP as a promising option for patients who have not reached their therapeutic goals with existing treatments.

Tirzepatide's innovative applications in the management of type 2 diabetes and its future prospects in cardiovascular health

Tirzepatide, a novel GLP-1/GIP dual receptor agonist, shows significant advantages in glycemic management and weight control. By summarizing the results of the SURMOUNT and SURPASS clinical trials, we evaluate the efficacy and safety of tirzepatide in reducing blood glucose and weight. These trials indicate that tirzepatide significantly lowers HbA1c levels (with a maximum reduction of 2.24%) and promotes weight loss (up to 11.2 kg) with good tolerability. However, there are still some challenges in its clinical application, including high treatment costs and gastrointestinal discomfort. Additionally, the safety and efficacy of tirzepatide in special populations, such as patients with renal impairment, require further investigation. Future large-scale clinical trials, such as SURPASS-CVOT and SUMMIT, are expected to further verify the long-term benefits of tirzepatide in cardiovascular health management, providing stronger evidence for its comprehensive treatment of diabetes and its complications.

Intermittent fasting and the liver: Focus on the Ramadan model

Intermittent fasting (IF) is an intervention that involves not only dietary modifications but also behavioral changes with the main core being a period of fasting alternating with a period of controlled feeding. The duration of fasting differs from one regimen to another. Ramadan fasting (RF) is a religious fasting for Muslims, it lasts for only one month every one lunar year. In this model of fasting, observers abstain from food and water for a period that extends from dawn to sunset. The period of daily fasting is variable (12-18 hours) as Ramadan rotates in all seasons of the year. Consequently, longer duration of daily fasting is observed during the summer. In fact, RF is a peculiar type of IF. It is a dry IF as no water is allowed during the fasting hours, also there are no calorie restrictions during feeding hours, and the mealtime is exclusively nighttime. These three variables of the RF model are believed to have a variable impact on different liver diseases. RF was evaluated by different observational and interventional studies among patients with non-alcoholic fatty liver disease and it was associated with improvements in anthropometric measures, metabolic profile, and liver biochemistry regardless of the calorie restriction among lean and obese patients. The situation is rather different for patients with liver cirrhosis. RF was associated with adverse events among patients with liver cirrhosis irrespective of the underlying etiology of cirrhosis. Cirrhotic patients developed new ascites, ascites were increased, had higher serum bilirubin levels after Ramadan, and frequently developed hepatic encephalopathy and acute upper gastrointestinal bleeding. These complications were higher among patients with Child class B and C cirrhosis, and some fatalities occurred due to fasting. Liver transplant recipients as a special group of patients, are vulnerable to dehydration, fluctuation in blood immunosuppressive levels, likelihood of deterioration and hence observing RF without special precautions could represent a real danger for them. Patients with Gilbert syndrome can safely observe RF despite the minor elevations in serum bilirubin reported during the early days of fasting.

GLP-1 mimetics and diabetic ketoacidosis: possible interactions and clinical consequences

Diabetic ketoacidosis is a serious diabetes-related consequence that occurs in type 1 diabetes and less commonly in type 2 diabetes and is a major cause of death. It results from the metabolic consequences due to a lack of insulin secretion or impaired insulin activity in diabetes leading to dysregulated pathophysiologic pathways resulting in excessive ketone body formation. While ketone bodies are physiologic molecules, their high levels reduce the physiological pH of the blood and induce ketoacidosis, leading to increasing metabolic dysfunction. Glucagon-like peptide-1 (GLP-1) mimetics are a class of recently developed diabetes therapy that do not lead to hypoglycemic, but some reports have suggested a relationship between GLP-1 mimetics and ketogenesis. To clarify the possible interactions between GLP-1 mimetics and ketogenesis in diabetes, this review was undertaken to collate and interpret the literature.

Teneligliptin: A potential therapeutic approach for diabetic cardiomyopathy

In this editorial, we comment on the article by Zhang et al. Diabetes mellitus is a chronic disorder associated with several complications like cardiomyopathy, neuropathy, and retinopathy. Diabetes prevalence is increasing worldwide. Multiple diabetes medications are prescribed based on individual patients' needs. However, the exact mechanisms by which many of these drugs exert their pro-tective effects remain unclear. Zhang et al elucidates molecular mechanisms undelaying cardioprotective effect of the dipeptidyl peptidase-IV inhibitor, teneligliptin. Briefly, teneligliptin alleviates the activation of NOD-like receptor protein 3 inflammasome, a multiprotein complex that plays a pivotal role in regulating the innate immune system and inflammatory signaling. Suppression of NOD-like receptor protein 3 inflammasome activity reduces the expression of cytokines, oxygen radicals and inflammation. These findings highlight teneligliptin as an anti-diabetic cardioprotective reagent.

Emerging therapeutic landscape: Incretin agonists in chronic kidney disease management

The increasing incidence of chronic kidney disease (CKD) poses a significant public health concern, prompting heightened attention to its treatment. Incretins, including glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide, are intestinal peptides released after nutrient intake, known for their hypoglycemic effects in diabetes management. Recent advancements highlight the promising outcomes of GLP-1 receptor agonists in reducing CKD risk factors and improving renal outcomes. The multifaceted functions of GLP-1, such as its anti-obesity, anti-hypertensive, anti-hyperglycemic, anti-lipid, anti-inflammatory, and endothelial function protective properties, contribute to its potential as a therapeutic agent for CKD. Although experiments suggest the potential benefits of incretin in CKD, a comprehensive understanding of its specific mechanisms is still lacking. This review aims to provide a detailed examination of current evidence and potential future directions, emphasizing the promising yet evolving landscape of incretin agonists in the context of CKD.

Identification of potential dipeptidyl peptidase IV inhibitors from the ConMedNP library by virtual screening, and molecular dynamics methods

In this study, we screened novel dipeptidyl peptidase IV (DPP4) inhibitors from the ConMedNP library consisting of 3507 molecules. Interestingly, molecular docking, ADMET, and the anti-diabetic activity predictions suggest that three molecules, namely OTH_UD_XX06_1, GB19, and BMC_000104, have a high binding affinity toward DPP4. The molecular dynamics (MD) simulation results suggest that these hit molecules have a stable binding pose and occupy the binding pockets throughout the 200 ns simulation. The presence of intermolecular H-bonding between the ligands and DPP4 was observed throughout the simulation period. Thus, docking and MD results, predicted that the three compounds were the most potent DPP4 inhibitors that could putatively bind to the DPP4 active site via both conventional H-bonding and hydrophobic interactions. These results could aid the discovery of new drugs to treat type 2 diabetes.

Potassium voltage-gated channel subfamily H member 2 (KCNH2) is a promising target for incretin secretagogue therapies

Derived from enteroendocrine cells (EECs), glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP) are pivotal incretin hormones crucial for blood glucose regulation. Medications of GLP-1 analogs and GLP-1 receptor activators are extensively used in the treatment of type 2 diabetes (T2D) and obesity. However, there are currently no agents to stimulate endogenous incretin secretion. Here, we find the pivotal role of KCNH2 potassium channels in the regulation of incretin secretion. Co-localization of KCNH2 with incretin-secreting EECs in the intestinal epithelium of rodents highlights its significance. Gut epithelial cell-specific KCNH2 knockout in mice improves glucose tolerance and increases oral glucose-triggered GLP-1 and GIP secretion, particularly GIP. Furthermore, KCNH2-deficient primary intestinal epithelial cells exhibit heightened incretin, especially GIP secretion upon nutrient stimulation. Mechanistically, KCNH2 knockdown in EECs leads to reduced K+ currents, prolonged action potential duration, and elevated intracellular calcium levels. Finally, we found that dofetilide, a KCNH2-specific inhibitor, could promote incretin secretion in enteroendocrine STC-1 cells in vitro and in hyperglycemic mice in vivo. These findings elucidate, for the first time, the mechanism and application of KCNH2 in regulating incretin secretion by EECs. Given the therapeutic promise of GLP-1 and GIP in diabetes and obesity management, this study advances our understanding of incretin regulation, paving the way for potential incretin secretagogue therapies in the treatment of diabetes and obesity.

Cardiovascular Protective Properties of GLP-1 Receptor Agonists: More than Just Diabetic and Weight Loss Drugs

Owing to their potent glucose-lowering efficacy and substantial weight loss effects, glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are now considered part of the frontline therapeutic options to treat both type 2 diabetes mellitus and nondiabetic overweight/obesity. Stemming from successful demonstration of their cardiometabolic modulation and reduction of major adverse cardiovascular events in clinical outcome trials, GLP-1 RAs have since been validated as agents with compelling cardiovascular protective properties. Studies spanning from the bench to preclinical and large-scale randomised controlled trials have consistently corroborated the cardiovascular benefits of this pharmacological class. Most notably, there is converging evidence that they exert favourable effects on atherosclerotic ischaemic endpoints, with preclinical data indicating that they may do so by directly modifying the burden and composition of atherosclerotic plaques. This narrative review examines the underlying pharmacology and clinical evidence behind the cardiovascular benefits of GLP-1 RAs, with particular focus on atherosclerotic cardiovascular disease. It also delves into the mechanisms that underpin their putative plaque-modifying actions, addresses existing knowledge gaps and therapeutic challenges and looks to future developments in the field, including the use of combination incretin agents for diabetes and weight loss management.

Adipose Tissue: A Novel Target of the Incretin Axis? A Paradigm Shift in Obesity-Linked Insulin Resistance

Adipose tissue (AT) represents a plastic organ that can undergo significant remodeling in response to metabolic demands. With its numerous checkpoints, the incretin system seems to play a significant role in controlling glucose homeostasis and energy balance. The importance of the incretin hormones, namely the glucagon-like peptide-1 (GLP-1) and the glucose-dependent insulinotropic peptide (GIP), in controlling the function of adipose cells has been brought to light by recent studies. Notably, a "paradigm shift" in reevaluating the role of the incretin system in AT as a potential target to treat obesity-linked metabolic disorders resulted from the demonstration that a disruption of the GIP and GLP-1 signaling axis in fat is associated with adiposity-induced insulin-resistance (IR) and/or type 2 diabetes mellitus (T2D). We will briefly discuss the (patho)physiological functions of GLP-1 and GIP signaling in AT in this review, emphasizing their potential impacts on lipid storage, adipogenesis, glucose metabolism and inflammation. We will also address the conundrum with the perturbation of the incretin axis in white or brown fat tissue and the emergence of metabolic disorders. In order to reduce or avoid adiposity-related metabolic complications, we will finally go over a potential scientific rationale for suggesting AT as a novel target for GLP-1 and GIP receptor agonists and co-agonists.

Assessment of Metabolic, Inflammatory, and Immunological Disorders Using a New Panel of Plasma Parameters in People Living with HIV Undergoing Antiretroviral Therapy-A Retrospective Study

Background/Objectives: People living with HIV (PLWH) treated with combined antiretroviral therapy (cART) show a greater predisposition to metabolic and inflammatory disturbances compared to the general population. This study aimed to assess the effect of five years of cART use on the level of selected parameters related to carbohydrate and lipid metabolism and inflammation in PLWH compared to the uninfected. Methods: The levels of sirtuins (-1, -3, -6); irisin (IRS); myostatin (MSTN); peptide YY (PYY); glucagon-like peptide-1 (GLP-1); dipeptidyl peptidase IV (DPP-4); fetuin-A (FETU-A); pentraxin 3 (PTX3); chemokine stromal cell-derived factor 1 (SDF-1); regulated on activation, normal T cell expressed and presumably secreted (RANTES); and interleukins (-4, -7, -15) in the plasma of PLWH and a control group were evaluated by immunoassay methods. The results obtained after five years of antiretroviral therapy were compared with the levels obtained before and one year after cART. Results: Analysis of the parameters after five years of cART showed significantly higher levels in PLWH compared to the control group for SIRT-6, IRS, and IL-4 and significantly lower levels for RANTES and IL-7. There were significantly higher levels of SIRT-6, PYY, GLP-1, and PTX3 obtained after five years of cART compared to the results before therapy and after one year of cART. Conclusions: The results indicated changes occur in the expression of selected parameters during cART use in PLWH. Further research on the clinical usefulness of selected parameters and obtaining new information on the development of HIV-related comorbidities needs to be conducted.

The impact of approved anti-obesity medications on osteoarthritis

BACKGROUND

Obesity has been established as a significant risk factor for osteoarthritis. Anti-obesity medications (AOMs) have demonstrated efficacy in weight management. However, potential impact on osteoarthritis risk remains uncertain.

METHODS

This retrospective cohort study used Kythera data from NOV2022 to JULY2024. Patients with obesity using AOMs were identified through diagnosis and prescription claims for tirzepatide, semaglutide, or liraglutide between 1NOV2023 and 31JAN2024, with a 6-month follow-up to assess OA risk. OA risk, analyzed using Cox regression and propensity score matching, controlled for comorbidities and sociodemographic factors.

RESULTS

There were 39,394 patients living with obesity using AOM (23,933 semaglutide 12,854 tirzepatide, 2,607 liraglutide) and 72,405 without AOM use. The adjusted osteoarthritis risk was 27% % lower in AOM users than in non-users (hazard ratio (HR) = 073, 95% CI (0.67-0.79), p < 0.01). Among AOMs, tirzepatide was associated with a significantly lower osteoarthritis (OA) risk compared to semaglutide (HR = 0.57, 95% CI: 0.50-0.65, p < 0.0001). Liraglutide was linked to a significantly higher OA risk vs tirzepatide (HR = 1.63, 95% CI: 1.23-2.15, p = 0.0007).

CONCLUSIONS

AOM use was associated with a significantly lower risk of OA and may be an effective obesity management intervention.

Glucagon-like Peptide 1 Receptor Agonist use and the effect on diabetic retinopathy: An uncertain relationship

Glucagon-like Peptide 1 Receptor Agonists (GLP-1 RAs) are a group of relatively novel medications for the treatment of diabetes mellitus. These medications can mimic the naturally occurring incretins of the body, which promote the release of insulin in response to hyperglycaemia. The anti-glycaemic effects of these medications can be profound and carry other metabolic benefits such as promoting weight loss. Clinical trials have shown GLP-1 RAs are safe to use from a cardiovascular perspective. However, some trials have suggested a link between GLP-1 RA use and worsening diabetic retinopathy. The conclusions surrounding this link are poorly established as data is drawn primarily from cardiovascular outcome trials. If an association does exist, a possible explanation might be the observed phenomenon of early worsening diabetic retinopathy with rapid correction of hyperglycaemic states. Trials which look at diabetic retinopathy as a primary outcome in relation to use of GLP-1 RAs are sparse and warrant investigation given the growing use of this group of medications. Therefore currently, it is uncertain what effect, beneficial or adverse, GLP-1 RA use has on diabetic retinopathy. This article provides an overview of GLP-1 RA use as a treatment for diabetes mellitus and the current understanding of their relationship with diabetic retinopathy.

Semaglutide for management of obesity in adolescents: efficacy, safety, and considerations for clinical practice

PURPOSE OF REVIEW

The purpose of this review is to describe the existing limited data related to the use of semaglutide in adolescents with obesity, supplementing with findings from adult studies of semaglutide use.

RECENT FINDINGS

Semaglutide, as a once weekly subcutaneous injection for weight management, effectively reduces body mass index (BMI) while improving hyperglycemia, elevated alanine aminotransferase levels, hyperlipidemia, and quality of life in youth with obesity. As of this review, only one large randomized clinical trial of semaglutide in youth has been completed, with a follow-up duration of 68 weeks. Thus, long-term data on the safety in adolescents is limited, particularly regarding the risks of cholelithiasis, pancreatitis, suicidal ideation, and disordered eating. Due to the cost of semaglutide, particularly in the United States, limited cost effectiveness analyses have demonstrated unfavorable incremental cost-effectiveness ratios for semaglutide relative to phentermine-topiramate as an alternative antiobesity medication in adolescents.

SUMMARY

Semaglutide represents an important advance in the pediatric obesity management, with clear short-term reductions in BMI and improvement in metabolic parameters. However, its long-term safety and efficacy for youth with obesity remain to be demonstrated. Additional research is needed to assess trends in utilization and adherence to minimize the risk of worsening socioeconomic disparities in pediatric obesity.

Glucagon-like Peptide-1 Receptor Agonists and Diabetic Osteopathy: Another Positive Effect of Incretines? A 12 Months Longitudinal Study

Diabetic osteopathy is a frequent complication in patients with type 2 diabetes mellitus (T2DM). The association between T2DM and increased fracture risk has led to study the impact of new antidiabetic drugs on bone metabolism. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are incretin mimetic drugs which have many pleiotropic properties. The relationship between GLP-1RAs and bone is very complex: while in vitro and animal studies have demonstrated a protective effect on bone, human studies are scarce. We led a 12 months longitudinal study evaluating bone changes in 65 patients withT2DM for whom a therapy with GLP-1RAs had been planned. Fifty-four T2DM patients completed the 12-month study period; of them, 30 had been treated with weekly dulaglutide and 24 with weekly semaglutide. One-year therapy with GLP-1RAs resulted in a significant reduction in weight and BMI. Bone mineral density (BMD), bone metabolism, trabecular bone score (TBS), adiponectin, and myostatin were evaluated before and after 12 months of GLP-1RAs therapy. After 12 months of therapy bone turnover markers and adiponectin showed a significant increase, while myostatin values showed a modest but significant reduction. BMD-LS by DXA presented a significant reduction while the reduction in BMD-LS by REMS was not significant and TBS values showed a marginal increase. Both DXA and REMS techniques showed a modest but significant reduction in femoral BMD. In conclusion, the use of GLP-1RAs for 12 months preserves bone quality and reactivates bone turnover. Further studies are needed to confirm whether GLP-1RAs could represent a useful therapeutic option for patients with T2DM and osteoporosis.

Potential kidney protective effects of glucagon-like peptide-1 receptor agonists

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) have gained increasing attention for their potential benefits in people with type 2 diabetes (T2DM) with chronic kidney disease (CKD). This class of medication has demonstrated promising results in reducing albuminuria, preserving estimated glomerular filtration rate (eGFR), and mitigating cardiovascular (CV) risk, making them potential therapeutic options for individuals with CKD. The kidney protective effects of GLP-1RAs extend beyond glycaemic control, and are thought to be attributed to their anti-inflammatory, antioxidant, and natriuretic properties. Despite these promising findings, the use of GLP-RAs has yet to be definitively shown to slow progression to chronic kidney failure, or reduce CV and kidney related death in people with T2DM and CKD. The Research Study to See How Semaglutide (a once weekly subcutaneous administered GLP-1RA) Works Compared to Placebo in People with Type 2 Diabetes and Chronic Kidney Disease (FLOW trial) was recently stopped because of efficacy. The primary end point for the FLOW trial consists of a composite endpoint of (i) onset of chronic kidney failure; (ii) death from kidney failure; (iii) cardiovascular death; and (iv) onset of a persistent ≥50% reduction in eGFR from baseline. It has also been reported by the sponsors of the trial that the primary end point of the trial was reduced by 24% with both CKD and CV outcomes contributing to risk reduction. In anticipation of the results of the FLOW trial being published, we review the current evidence surrounding kidney outcomes and proposed kidney protective pathways associated with GLP-1RA use.

The incretin effect in type 2 diabetes in a Sub-Saharan African population

AIM

Type 2 diabetes is increasing in Sub-Saharan Africa, but the pathophysiology in this population is poorly investigated. In Western populations, the incretin effect is reduced in type 2 diabetes, leading to lowered insulin secretion. The aim of this study was to investigate the incretin effect in a group of Sub-Saharan Africans with type 2 diabetes.

METHODS

Twenty adults diagnosed with type 2 diabetes, based on either an oral glucose tolerance test (n = 10) or on glycated hemoglobin A1c (n = 10), and 10 non-diabetic controls were included in an interventional study in Tanzania. We investigated the incretin effect as the difference between the plasma insulin area under the curve during an oral glucose tolerance test and that obtained during an intravenous glucose infusion. Differences between diabetes groups were analyzed by Kruskal-Wallis one-way analysis of variance.

RESULTS

The incretin effect did not differ between groups (p = 0.45), and there was no difference in plasma concentrations of the incretin hormones during the OGTT.

CONCLUSION

A reduced incretin effect appears not to contribute to hyperglycemia in type 2 diabetes in this Tanzanian population. More research is needed to explain the diabetes phenotype often seen in Sub-Saharan Africa.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT03106480 , date of registration: 04/10/2017.

Mechanisms of action and therapeutic applications of GLP-1 and dual GIP/GLP-1 receptor agonists

Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are two incretins that bind to their respective receptors and activate the downstream signaling in various tissues and organs. Both GIP and GLP-1 play roles in regulating food intake by stimulating neurons in the brain's satiety center. They also stimulate insulin secretion in pancreatic β-cells, but their effects on glucagon production in pancreatic α-cells differ, with GIP having a glucagonotropic effect during hypoglycemia and GLP-1 exhibiting glucagonostatic effect during hyperglycemia. Additionally, GIP directly stimulates lipogenesis, while GLP-1 indirectly promotes lipolysis, collectively maintaining healthy adipocytes, reducing ectopic fat distribution, and increasing the production and secretion of adiponectin from adipocytes. Together, these two incretins contribute to metabolic homeostasis, preventing both hyperglycemia and hypoglycemia, mitigating dyslipidemia, and reducing the risk of cardiovascular diseases in individuals with type 2 diabetes and obesity. Several GLP-1 and dual GIP/GLP-1 receptor agonists have been developed to harness these pharmacological effects in the treatment of type 2 diabetes, with some demonstrating robust effectiveness in weight management and prevention of cardiovascular diseases. Elucidating the underlying cellular and molecular mechanisms could potentially usher in the development of new generations of incretin mimetics with enhanced efficacy and fewer adverse effects. The treatment guidelines are evolving based on clinical trial outcomes, shaping the management of metabolic and cardiovascular diseases.

Molecular dynamics-guided optimization of BGM0504 enhances dual-target agonism for combating diabetes and obesity

The dual activation of glucagon-like peptide-1 receptor (GLP-1R) and glucose-dependent insulinotropic polypeptide receptor (GIPR) has emerged as a promising therapeutic strategy for managing type 2 diabetes and obesity. Tirzepatide, a dual agonist peptide, has exhibited superior clinical efficacy in glycemic and weight control compared to selective GLP-1R agonists. Nevertheless, the structural basis of Tirzepatide's extended half-life, attributed to an acylation side chain on the parent peptide, raises questions regarding its partial agonistic activity. Employing molecular dynamics simulations, we explored the dynamic processes of peptide-receptor interactions. We uncovered a crucial salt bridge between parent peptide and GLP-1R/GIPR at K20, a feature not discernible in cryo-electron microscopy structures. Building upon these insights, we developed an optimization strategy based on the parent peptide which involved repositioning the acylation side chain. The results of both in vitro and in vivo experiments demonstrated that the optimized peptide has twofold to threefold increase in agonistic activity compared to Tirzepatide while maintaining its extended half-life in plasma. This led to the design of BGM0504, which proved to be more effective than its predecessor, Tirzepatide, in both laboratory and animal studies.

Surrogate measures of first-phase insulin secretion versus reference methods intravenous glucose tolerance test and hyperglycemic clamp: a systematic review and meta-analyses

INTRODUCTION

In this systematic review, we investigated the diagnostic accuracy of surrogate measures of insulin secretion based on fasting samples and the oral glucose tolerance test (OGTT). The first phase of insulin secretion was calculated using two gold standard methods; the hyperglycemic clamp (HGC) test and intravenous glucose tolerance test (IVGTT).

RESEARCH DESIGN AND METHODS

We conducted searches in the PubMed, Cochrane Central, and Web of Science databases, the last of which was conducted at the end of June 2021. Studies were included that measured first-phase insulin secretion in adults using both a gold-standard reference method (either HGC or IVGTT) and one or more surrogate measures from either fasting samples, OGTT or a meal-tolerance test. QUADAS-2, a revised tool for the quality assessment of diagnostic accuracy studies, was used for quality assessment. Random-effects meta-analyses were performed to examine the correlation between first-phase measured with gold standard and surrogate methods.

RESULTS

A total of 33 articles, encompassing 5362 individuals with normal glucose tolerance, pre-diabetes or type 2 diabetes, were included in our systematic review. Homeostatic model assessment (HOMA)-beta and Insulinogenic Index 30 (IGI(30)) were the surrogate measures validated in the largest number of studies (17 and 13, respectively). HOMA-beta's pooled correlation to the reference methods was 0.48 (95% CI 0.40 to 0.56) The pooled correlation of IGI to the reference methods was 0.61 (95% CI 0.54 to 0.68). The surrogate measures with the highest correlation to the reference methods were Kadowaki (0.67 (95% CI 0.61 to 0.73)) and Stumvoll's first-phase secretion (0.65 (95% CI 0.58 to 0.71)), both calculated from an OGTT.

CONCLUSIONS

Surrogate measures from the first 30 min of an OGTT capture the first phase of insulin secretion and are a good choice for epidemiological studies. HOMA-beta has a moderate correlation to the reference methods but is not a measure of the first phase specifically.

PROSPERO REGISTRATION NUMBER

The meta-analysis was registered at PROSPERO (Id: CRD42020169064) before inclusion started.

Differential Diagnosis of Post Pancreatitis Diabetes Mellitus Based on Pancreatic and Gut Hormone Characteristics

CONTEXT

Distinguishing different types of diabetes is important in directing optimized treatment strategies and correlated epidemiological studies.

OBJECTIVE

Through detailed analysis of hormone responses to mixed meal tolerance test (MMTT), we aimed to find representing characteristics of post-acute pancreatitis diabetes mellitus (PPDM-A) and post-chronic pancreatitis diabetes mellitus (PPDM-C).

METHODS

Participants with PPDM-A, PPDM-C, type 1 diabetes, type 2 diabetes, and normal controls (NCs) underwent MMTT. Fasting and postprandial responses of serum glucose, C-peptide, insulin, glucagon, pancreatic polypeptide (PP), ghrelin, gastric inhibitory peptide (GIP), glucagon like peptide-1 (GLP-1), and peptide YY (PYY) were detected and compared among different groups. Focused analysis on calculated insulin sensitivity and secretion indices were performed to determine major causes of hyperglycemia in different conditions.

RESULTS

Participants with PPDM-A were characterized by increased C-peptide, insulin, glucagon, and PP, but decreased ghrelin, GIP, and PYY compared with NCs. Patients with PPDM-C showed secretion insufficiency of C-peptide, insulin, ghrelin, and PYY, and higher postprandial responses of glucagon and PP than NCs. In particular, both fasting and postprandial levels of ghrelin in PPDM-C were significantly lower than other diabetes groups. PYY responses in patients with PPDM-A and PPDM-C were markedly reduced. Additionally, the insulin sensitivity of PPDM-A was decreased, and the insulin secretion for PPDM-C was decreased.

CONCLUSION

Along with the continuum from acute to chronic pancreatitis, the pathological mechanism of PPDM changes from insulin resistance to insulin deficiency. Insufficient PYY secretion is a promising diagnostic marker for distinguishing PPDM from type 1 and type 2 diabetes. Absent ghrelin secretion to MMTT may help identify PPDM-C.

Liraglutide for the Treatment of Weight Regain After Bariatric Surgery: A Systematic Review and Meta-analysis

INTRODUCTION

The efficacy of liraglutide for treating type 2 diabetes mellitus and obesity is well established, but their role in the treatment of weight regain after bariatric surgery remains unclear.

METHODS

We searched PubMed, Embase, and Cochrane Library databases in January 2024. A random-effects model was employed to compute mean differences (MD) and events per 100 observations with 95% confidence intervals (CI) for continuous and binary endpoints. Statistical analysis was performed using R software.

RESULTS

A total of 16 studies were included and 881 individuals. Patients were mostly female (50%), aged 36 to 55 years, with a mean body mass index (BMI) of 39.4 kg/m2, and had BS surgery 5 years prior. Over a mean follow-up time ranging from 3 months to 4 years, it was observed a statistically significant reduction in BMI (MD - 8.56 kg/m2; 95% CI 3.34 to 13.79; p < 0.01) and a mean reduction in total weight (MD - 16.03 kg; 95% CI 0.03 to 32.02; p = 0.05) after liraglutide use. Additionally, 65% of patients undertaking liraglutide showed total body weight loss (BWL) above 5% (65.8 events per 100 observations; 95% CI 54.96 to 75.20; p < 0.01), while 26% lost more than 10% of total BWL (26.77 events per 100 observations; 95% CI 19.17 to 36.02; p < 0.01). A limitation is a variability between the studies.

CONCLUSIONS

Our findings support the use of liraglutide for weight management in patients who experience weight regain after BS. Liraglutide is well tolerated and promotes significant weight loss, providing clinicians with a therapeutic option for this clinical challenge.

Unraveling the Health Benefits and Mechanisms of Time-Restricted Feeding: Beyond Caloric Restriction

Time-restricted feeding (TRF) is a lifestyle intervention that aims to maintain a consistent daily cycle of feeding and fasting to support robust circadian rhythms. Recently, it has gained scientific, medical, and public attention due to its potential to enhance body composition, extend lifespan, and improve overall health, as well as induce autophagy and alleviate symptoms of diseases like cardiovascular diseases, type 2 diabetes, neurodegenerative diseases, cancer, and ischemic injury. However, there is still considerable debate on the primary factors that contribute to the health benefits of TRF. Despite not imposing strict limitations on calorie intake, TRF consistently led to reductions in calorie intake. Therefore, while some studies suggest that the health benefits of TRF are primarily due to caloric restriction (CR), others argue that the key advantages of TRF arise not only from CR but also from factors like the duration of fasting, the timing of the feeding period, and alignment with circadian rhythms. To elucidate the roles and mechanisms of TRF beyond CR, this review incorporates TRF studies that did not use CR, as well as TRF studies with equivalent energy intake to CR, which addresses the previous lack of comprehensive research on TRF without CR and provides a framework for future research directions.

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.

Comparative efficacy of exercise, diet and/or pharmacological interventions on BMI, ovulation, and hormonal profile in reproductive-aged women with overweight or obesity: a systematic review and network meta-analysis

BACKGROUND

The increasing prevalence of obesity worldwide poses a significant threat to reproductive function owing, in part, to hormonal disturbances caused by negative feedback between excess adiposity and the hypothalamic-pituitary-ovarian axis. Consequently, finding the most appropriate strategies to lose weight and improve ovulation in women with overweight or obesity is a clinically relevant matter that needs to be investigated. A comprehensive comparison of the independent and combined efficacy of lifestyle and/or pharmacological interventions on BMI, ovulation, and hormonal profile in women with overweight or obesity at risk of anovulatory infertility would facilitate improving fertility strategies in this population.

OBJECTIVE AND RATIONALE

This study aimed to evaluate the comparative efficacy of exercise, diet, and pharmacological interventions on BMI, ovulation, and hormonal profile in reproductive-aged women with overweight or obesity.

SEARCH METHODS

A systematic review was performed by searching PubMed, Scopus, Web of Science, PsycINFO, and Cochrane Library up to 14 December 2023, for randomized controlled trials assessing the effects of exercise, diet and/or pharmacological interventions (i.e. weight-lowering drugs or ovulation inducers) on BMI, ovulation, and/or hormonal profile in reproductive-aged women with overweight or obesity. We performed frequentist random-effect network meta-analyses and rated the certainty of the evidence. The primary outcomes were BMI and ovulation rate, and the secondary outcomes were serum reproductive hormone levels (gonadotrophins, androgens, or oestrogens). We performed sensitivity analyses, including the studies that only involved women with PCOS.

OUTCOMES

Among 1190 records screened, 148 full texts were assessed for eligibility resulting in 95 trials (9910 women), of which 53% presented a high or unclear risk of bias. The network meta-analyses revealed that, compared to control: diet combined with weight-lowering drugs (mean difference (MD) -2.61 kg/m2; 95% CI -3.04 to -2.19; τ2 = 0.22) and adding exercise (MD -2.35 kg/m2; 95% CI -2.81 to -1.89; τ2 = 0.22) led to the greatest decrease in BMI; exercise combined with diet and ovulation inducers (risk ratio (RR) 7.15; 95% CI 1.94-26.40; τ2 = 0.07) and exercise combined with diet and weight-lowering drugs (RR 4.80; 95% CI 1.67-13.84; τ2 = 0.07) produced the highest increase in ovulation rate; and exercise combined with diet and weight-lowering drugs was the most effective strategy in reducing testosterone levels (standardized mean difference (SMD) -2.91; 95% CI -4.07 to -1.74; τ2 = 2.25), the third most effective strategy in increasing sex hormone-binding globulin levels (SMD 2.37; 95% CI 0.99-3.76; τ2 = 2.48), and it was coupled with being ranked first in terms of free androgen index reduction (SMD -1.59; 95% CI -3.18 to 0.01; τ2 = 1.91). The surface under the cumulative ranking curve scores suggested that: diet combined with weight-lowering drugs is the strategy most likely (94%) to produce the highest BMI reduction; and exercise combined with diet and ovulation inducers is the strategy most likely (89%) to produce the highest ovulation rate improvement. The sensitivity analyses, which exclusively included studies involving women diagnosed with PCOS, were consistent with the results presented above.

WIDER IMPLICATIONS

Overall, the findings of this network meta-analysis indicate that the combination of exercise, diet, and pharmacological interventions is effective for weight loss, improving ovulation, and normalizing the androgen levels of women with overweight or obesity. Although higher quality studies are needed, these results support that the optimal treatment strategy for women with overweight or obesity wishing to conceive must consider exercise, diet, and pharmacological interventions during the shared decision-making process.

Examining the Potential Applicability of Orexigenic and Anorexigenic Peptides in Veterinary Medicine for the Management of Obesity in Companion Animals

This review article comprehensively explores the role of orexigenic and anorexigenic peptides in the management of obesity in companion animals, with a focus on clinical applications. Obesity in domestic animals, particularly dogs and cats, is prevalent, with significant implications for their health and well-being. Factors contributing to obesity include overfeeding, poor-quality diet, lack of physical activity, and genetic predispositions. Despite the seriousness of this condition, it is often underestimated, with societal perceptions sometimes reinforcing unhealthy behaviors. Understanding the regulation of food intake and identifying factors affecting the function of food intake-related proteins are crucial in combating obesity. Dysregulations in these proteins, whether due to genetic mutations, enzymatic dysfunctions, or receptor abnormalities, can have profound health consequences. Molecular biology techniques play a pivotal role in elucidating these mechanisms, offering insights into potential therapeutic interventions. The review categorizes food intake-related proteins into anorexigenic peptides (inhibitors of food intake) and orexigenic peptides (enhancers of food intake). It thoroughly examines current research on regulating energy balance in companion animals, emphasizing the clinical application of various peptides, including ghrelin, phoenixin (PNX), asprosin, glucagon-like peptide 1 (GLP-1), leptin, and nesfatin-1, in veterinary obesity management. This comprehensive review aims to provide valuable insights into the complex interplay between peptides, energy balance regulation, and obesity in companion animals. It underscores the importance of targeted interventions and highlights the potential of peptide-based therapies in improving the health outcomes of obese pets.

Rebalancing the Gut: Glucagon-Like Peptide-1 Agonists as a Strategy for Obesity and Metabolic Health

Obesity significantly impacts gut microbial composition, exacerbating metabolic dysfunction and weight gain. Traditional treatment methods often fall short, underscoring the need for innovative approaches. Glucagon-like peptide-1 (GLP-1) agonists have emerged as promising agents in obesity management, demonstrating significant potential in modulating gut microbiota. These agents promote beneficial bacterial populations, such as Bacteroides, Lactobacillus, and Bifidobacterium, while reducing harmful species like Enterobacteriaceae. By influencing gut microbiota composition, GLP-1 agonists enhance gut barrier integrity, reducing permeability and systemic inflammation, which are hallmarks of metabolic dysfunction in obesity. Additionally, GLP-1 agonists improve metabolic functions by increasing the production of short-chain fatty acids like butyrate, propionate, and acetate, which serve as energy sources for colonocytes, modulate immune responses, and enhance the production of gut hormones that regulate appetite and glucose homeostasis. By increasing microbial diversity, GLP-1 agonists create a more resilient gut microbiome capable of resisting pathogenic invasions and maintaining metabolic balance. Thus, by shifting the gut microbiota toward a healthier profile, GLP-1 agonists help disrupt the vicious cycle of obesity-induced gut dysbiosis and inflammation. This review highlights the intricate relationship between obesity, gut microbiota, and GLP-1 agonists, providing valuable insights into their combined role in effective obesity treatment and metabolic health enhancement.

Duodenal-jejunal bypass surgery activates eNOS and enhances antioxidant system by activating AMPK pathway to improve heart oxidative stress in diabetic cardiomyopathy rats

BACKGROUND

Diabetic cardiomyopathy is a serious complication of obesity with type 2 diabetes and is a major cause of mortality. Metabolic surgery, such as duodenal-jejunal bypass (DJB), can effectively improve diabetic cardiomyopathy; however, the underlying mechanisms remain elusive. Oxidative stress is one of the pivotal mechanisms of diabetic cardiomyopathy. Our objective was to investigate the effect and potential mechanisms of DJB on oxidative stress in the heart of diabetic cardiomyopathy rats.

METHODS

High-fat diet combined with intraperitoneal injection of streptozotocin was used to establish diabetic cardiomyopathy rats. DJB was performed on diabetic cardiomyopathy rats, and high glucose and palmitate were used to simulate diabetic cardiomyopathy in H9C2 cells in vitro. Sera from different groups of rats were used for experiments in vivo and in vitro.

RESULTS

DJB effectively improved oxidative stress and activated the adenosine monophosphate (AMP)-activated protein kinase (AMPK) pathway to increase endothelial nitric oxide synthase (eNOS) phosphorylation level and the expression of antioxidative system-related proteins and genes in the heart of diabetic cardiomyopathy rats. AMPK agonists and serum from DJB rats activated the AMPK pathway to increase eNOS phosphorylation level and the expression of antioxidative system-related proteins and genes and decreased the content of reactive oxygen species in H9C2 cells, but this improvement was almost eliminated by the addition of AMPK inhibitors.

CONCLUSIONS

DJB activates eNOS and enhances the antioxidant system by activating the AMPK pathway-and not solely by improving blood glucose-to improve oxidative stress in the heart of diabetic cardiomyopathy rats.

GIP-derived GIP receptor antagonists - a review of their role in GIP receptor pharmacology

Surprisingly, agonists, as well as antagonists of the glucose-dependent insulinotropic polypeptide receptor (GIPR), are currently being used or investigated as treatment options for type 2 diabetes and obesity - and both, when combined with glucagon-like peptide 1 receptor (GLP-1R) agonism, enhance GLP-1-induced glycemia and weight loss further. This paradox raises several questions regarding not only the mechanisms of actions of GIP but also the processes engaged during the activation of both the GIP and GLP-1 receptors. Here, we provide an overview of studies of the properties and actions of peptide-derived GIPR antagonists, focusing on GIP(3-30)NH2, a naturally occurring N- and C-terminal truncation of GIP(1-42). GIP(3-30)NH2 was the first GIPR antagonist administered to humans. GIP(3-30)NH2 and a few additional antagonists, like Pro3-GIP, have been used in both in vitro and in vivo studies to elucidate the molecular and cellular consequences of GIPR inhibition, desensitization, and internalization and, at a larger scale, the role of the GIP system in health and disease. We provide an overview of these studies combined with recent knowledge regarding the effects of naturally occurring variants of the GIPR system and species differences within the GIP system to enhance our understanding of the GIPR as a drug target.

Metabolic Effects of Ketogenic Diets: Exploring Whole-Body Metabolism in Connection with Adipose Tissue and Other Metabolic Organs

The ketogenic diet (KD) is characterized by minimal carbohydrate, moderate protein, and high fat intake, leading to ketosis. It is recognized for its efficiency in weight loss, metabolic health improvement, and various therapeutic interventions. The KD enhances glucose and lipid metabolism, reducing triglycerides and total cholesterol while increasing high-density lipoprotein levels and alleviating dyslipidemia. It significantly influences adipose tissue hormones, key contributors to systemic metabolism. Brown adipose tissue, essential for thermogenesis and lipid combustion, encounters modified UCP1 levels due to dietary factors, including the KD. UCP1 generates heat by uncoupling electron transport during ATP synthesis. Browning of the white adipose tissue elevates UCP1 levels in both white and brown adipose tissues, a phenomenon encouraged by the KD. Ketone oxidation depletes intermediates in the Krebs cycle, requiring anaplerotic substances, including glucose, glycogen, or amino acids, for metabolic efficiency. Methylation is essential in adipogenesis and the body's dietary responses, with DNA methylation of several genes linked to weight loss and ketosis. The KD stimulates FGF21, influencing metabolic stability via the UCP1 pathways. The KD induces a reduction in muscle mass, potentially involving anti-lipolytic effects and attenuating proteolysis in skeletal muscles. Additionally, the KD contributes to neuroprotection, possesses anti-inflammatory properties, and alters epigenetics. This review encapsulates the metabolic effects and signaling induced by the KD in adipose tissue and major metabolic organs.