The evolving story of incretins (GIP and GLP-1) in metabolic and cardiovascular disease: A pathophysiological update

Unlocking the multifaceted roles of GLP-1: Physiological functions and therapeutic potential

Glucagon (GCG) like peptide 1 (GLP-1) has emerged as a powerful player in regulating metabolism and a promising therapeutic target for various chronic diseases. This review delves into the physiological roles of GLP-1, exploring its impact on glucose homeostasis, insulin secretion, and satiety. We examine the compelling evidence supporting GLP-1 receptor agonists (GLP-1RAs) in managing type 2 diabetes (T2D), obesity, and other diseases. The intricate molecular mechanisms underlying GLP-1RAs are explored, including their interactions with pathways like extracellular signal-regulated kinase 1/2 (ERK1/2), activated protein kinase (AMPK), cyclic adenine monophosphate (cAMP), mitogen-activated protein kinase (MAPK), and protein kinase C (PKC). Expanding our understanding, the review investigates the potential role of GLP-1 in cancers. Also, microribonucleic acid (RNA) (miRNAs), critical regulators of gene expression, are introduced as potential modulators of GLP-1 signaling. We delve into the link between miRNAs and T2D obesity and explore specific miRNA examples influencing GLP-1R function. Finally, the review explores the rationale for seeking alternatives to GLP-1RAs and highlights natural products with promising GLP-1 modulatory effects.

Tirzepatide and major adverse limb events: Insights from a multicenter real-world analysis in PAD and diabetes patients

AIMS

Peripheral artery disease (PAD) is a major diabetic complication and a leading cause of amputation. While GLP-1 receptor agonists (GLP-1 RAs) provide cardiovascular and limb protection, the impact of tirzepatide, a dual GLP-1/GIP receptor agonist, on major adverse limb events (MALEs) remains unclear. This study assessed tirzepatide's association with MALE risk in patients with PAD and diabetes using real-world data.

METHODS

This retrospective cohort study analyzed 8,046 propensity score-matched PAD patients with diabetes (4,023 on tirzepatide, 4,023 controls) from the TriNetX database. The primary outcome was MALEs, with secondary outcomes including all-cause mortality, acute stroke, acute myocardial infarction (AMI), and major adverse cardiovascular events (MACEs). Cox models and Kaplan-Meier curves were used for analysis.

RESULTS

Tirzepatide significantly reduced MALE risk (HR: 0.44, 95 % CI: 0.33-0.59, p < 0.001) and was associated with lower mortality, stroke, and MACEs. AMI risk was similar between groups (HR: 0.85, p = 0.29). Subgroup analyses confirmed consistent findings, except in those with prior stroke.

CONCLUSIONS

Tirzepatide significantly lowered MALE risk in PAD patients with diabetes, suggesting a potential therapeutic role. Further prospective studies are needed to validate these findings.

Novel therapeutic agents for cardiometabolic risk mitigation in heart transplant recipients

Heart transplant (HT) recipients experience high rates of cardiometabolic disease. Novel therapies targeting hyperlipidemia, diabetes, and obesity, including proprotein convertase subtilisin/kexin inhibitors, sodium-glucose cotransporter-2 inhibitors, and glucagon-like peptide-1 agonists, are increasingly used for cardiometabolic risk mitigation in the general population. However, limited data exist to support the use of these agents in patients who have undergone heart transplantation. Herein, we describe the mechanisms of action and emerging evidence supporting the use of novel pharmacologic agents in the post-HT setting for cardiometabolic risk mitigation and review evidence supporting their ability to modulate immune pathways associated with atherogenesis, epicardial adipose tissue, and coronary allograft vasculopathy.

Expectations and Outcomes From Glucagon-Like Peptide-1 Receptor Agonists As Adjunct Treatment for Type 1 Diabetes - Case Presentations

BACKGROUND

Type 1 diabetes (T1D) is characterized by the autoimmune destruction of pancreatic beta cells, leading to lifelong insulin dependence. Despite advancements in insulin therapies and glucose monitoring, maintaining optimal blood glucose control remains challenging with common issues like weight gain and glucose variability. Glucagon-like peptide 1 receptor agonists (GLP-1 RAs), approved for type 2 diabetes and obesity, are being explored off-label for T1D.

CASE REPORT

This case series investigates the effectiveness of GLP-1 RAs, mainly semaglutide and tirzepatide, as an adjunct therapy to insulin in adolescents and young adults (AYA) with T1D, in a single center, providing real-world insights and highlighting practical issues.

DISCUSSION

Most patients had obesity, consistent with typical indication for use in AYA. Common gastrointestinal side effects improved with dose titration, but careful monitoring is needed for persistent symptoms. One patient developed an eating disorder, underscoring the need for vigilance. Insurance and medication shortage issues impacted treatment continuity, highlighting the need for better support. Glycemic parameters improved in most patients, with weight reduction in several patients with obesity, and no reported diabetic ketoacidosis.

CONCLUSIONS

GLP-1 RAs can be a beneficial adjunct therapy in T1D, improving glycemic control, reducing insulin needs, and supporting weight management, while potentially preventing long-term cardiovascular and renal complications.

The effect of antidiabetic drugs on bone metabolism: a concise review

Diabetes mellitus (DM) is a complex metabolic disorder characterized by chronic hyperglycemia, which derives from either insufficient insulin production [type 1 diabetes mellitus (T1DM)] or both impaired insulin sensitivity along with inadequate insulin production [type 2 diabetes mellitus (T2DM)] and affects millions of people worldwide. In addition to the adverse effects of DM on classical target organs and tissues, skeletal health can also be adversely affected. There is considerable evidence linking DM with osteoporosis. The fracture risk in patients with DM differs upon the type of diabetes, and it appears to be related to the type of anti-diabetic treatment. Antidiabetic drugs may have various effects on bone health. Most of them have neutral or even favorable effects on bone metabolism with the exception of thiazolidinediones (TZDs). Some studies suggest that TZDs may have negative impact on bone health by decreasing bone formation and increasing the fracture risk. There are also limited studies linking the use of canagliflozin, a Sodium-glucose contransporter-2 inhibitor (SGLT2i), with increased fracture risk. On the other hand, therapies that are based on incretin effect, like Dipeptidyl peptidase-4 inhibitors (DPP-4i) and Glucagon-like peptide-1 receptor agonizts (GLP-1RAs) might have positive effects on bone health by promoting bone formation. Herein we review the impact of antidiabetic drugs on bone health, highlighting the potential benefits and risks associated with these medications in an attempt to contribute to the development of personalized treatment strategies for individuals with DM.

Tirzepatide Associated With Reduced Albuminuria in Participants With Type 2 Diabetes: Pooled Post Hoc Analysis From the Randomized Active- and Placebo-Controlled SURPASS-1-5 Clinical Trials

OBJECTIVE

Tirzepatide, a long-acting, glucose-dependent insulinotropic polypeptide/glucagon-like peptide 1 receptor agonist, reduced urine albumin-to-creatinine ratio (UACR) and estimated glomerular filtration rate (eGFR) decline in people with type 2 diabetes and high cardiovascular risk in the SURPASS-4 trial. To examine the generalizability of these findings, we assessed change from baseline in UACR for tirzepatide (5, 10, and 15 mg) compared with active and placebo treatment in a broad population from the SURPASS-1-5 trials.

RESEARCH DESIGN AND METHODS

This post hoc analysis examined data from the overall pooled SURPASS-1-5 population and subgroups defined by baseline UACR ≥30 mg/g. A mixed model for repeated measures was used to analyze on-treatment data from baseline to the end-of-treatment visit. Study identifier was included in the model as a covariate.

RESULTS

The adjusted mean percent change from baseline in UACR for tirzepatide 5, 10, or 15 mg compared with all pooled comparators was -19.3% (95% CI -25.5, -12.5), -22.0% (-28.1, -15.3), and -26.3 (-32.0, -20.0), respectively, at week 40/42. Results were similar across pooled placebo, active, and insulin comparator studies. UACR lowering appeared more pronounced in subgroups with UACR ≥30 mg/g. Mediation analysis findings suggested that approximately one-half of the reduction in albuminuria associated with tirzepatide may be weight loss related. There was no difference in eGFR between tirzepatide and pooled comparators at week 40/42.

CONCLUSIONS

In this post hoc analysis in people with type 2 diabetes, including those with chronic kidney disease, tirzepatide was associated with a clinically relevant decreased UACR versus comparators, suggesting a potential kidney-protective effect.

Impact of Dietary Fiber on Inflammation in Humans

Cohort studies consistently show that a high intake of cereal fiber and whole-grain products is associated with a decreased risk of type 2 diabetes (T2DM), cancer, and cardiovascular diseases. Similar findings are also reported for infectious and chronic inflammatory disorders. All these disorders are at least partially caused by inflammaging, a chronic state of inflammation associated with aging and Metabolic Syndrome. Surprisingly, insoluble (cereal) fiber intake consistently shows stronger protective associations with most long-term health outcomes than soluble fiber. Most humans consume soluble fiber mainly from sweet fruits, which usually come with high levels of sugar, counteracting the potentially beneficial effects of fiber. In both observational and interventional studies, high-fiber diets show a beneficial impact on inflammation, which can be attributed to a variety of nutrients apart from dietary fiber. These confounders need to be considered when evaluating the effects of fiber as part of complex dietary patterns. When assessing specific types of fiber, inulin and resistant starch clearly elicit anti-inflammatory short-term effects, while results for pectins, beta-glucans, or psyllium turn out to be less convincing. For insoluble fiber, promising but sparse data have been published so far. Hypotheses on putative mechanisms of anti-inflammatory fiber effects include a direct impact on immune cells (e.g., for pectin), fermentation to pleiotropic short-chain fatty acids (for fermentable fiber only), modulation of the gut microbiome towards higher levels of diversity, changes in bile acid metabolism, a differential release of gut hormones (such as the glucose-dependent insulinotropic peptide (GIP)), and an improvement of insulin resistance via the mTOR/S6K1 signaling cascade. Moreover, the contribution of phytate-mediated antioxidative and immune-modulatory means of action needs to be considered. In this review, we summarize the present knowledge on the impact of fiber-rich diets and dietary fiber on the human inflammatory system. However, given the huge heterogeneity of study designs, cohorts, interventions, and outcomes, definite conclusions on which fiber to recommend to whom cannot yet be drawn.

Capturing the Additional Cardiovascular Benefits of SGLT2 Inhibitors and GLP-1 Receptor Agonists Beyond the Control of Traditional Risk Factors in People With Diabetes

OBJECTIVES

This study aimed to quantify the additional cardioprotective effects of sodium-glucose cotransporter 2 inhibitors (SGLT2is) and glucagon-like peptide-1 receptor agonists (GLP-1RAs) beyond the traditional risk factors control in individuals with type 2 diabetes. This helps calibrate the Building, Relating, Assessing, and Validating Outcomes (BRAVO) diabetes simulation model to capture the total cardiovascular benefits of new diabetes medications accurately.

METHODS

We extracted patient characteristics and treatment efficacy data from 4 cardiovascular outcome trials (CVOTs) of SGLT2is and 4 CVOTs of GLP-1RAs completed before May 2023. Using the BRAVO diabetes simulation model, we translated reductions in traditional risk factors (ie, glycated hemoglobin, systolic blood pressure, low-density lipids, and body mass index) from the newer drugs into risk reductions in cardiovascular outcomes (ie, myocardial infarction [MI], stroke, congestive heart failure [CHF], and mortality), assuming that the drug-associated risk reductions were only driven by traditional risk factors. Then, we compared the simulated risk-factor-driven risk reductions of cardiovascular outcomes with observed risk reductions from the trials and calculated drug-specific incremental benefits (DIB).

RESULTS

After accounting for the cardiovascular effects from traditional risk factors control, SGLT2is was associated with an additional 19% risk reduction in CHF (DIB: 0.81, 95% CI 0.72-0.90). Furthermore, the uncalibrated model predicted a risk reduction in stroke with SGLT2is, which was not observed in CVOTs. This discrepancy highlights the need for an SGLT2i-specific calibrator to align the simulation results with the observed outcomes. In contrast, no additional cardiovascular benefit was associated with GLP-1RAs after controlling for traditional risk factors.

CONCLUSIONS

Our study revealed that SGLT2is could further reduce CHF risk beyond the control of traditional risk factors but may offer additional pathways to offset the overall benefits of traditional risk factor control in stroke risk. No additional cardiovascular benefits were observed for GLP-1RAs beyond traditional risk factor control. The BRAVO model calibration enhances cardiovascular outcome prediction with these newer antidiabetic therapies.

Tirzepatide alleviates oxidative stress and inflammation in diabetic nephropathy via IL-17 signaling pathway

Oxidative stress (OS) and inflammation play essential roles in the development of diabetic nephropathy (DN). Tirzepatide (TZP) has a protective effect in diabetes. However, its underlying mechanism in DN remains unclear. DN model mice were induced by intraperitoneal injection of streptozotocin (STZ; 60 mg/kg), followed by administration of different doses of TZP (3 and 10 nmol/kg) via intraperitoneal injection for 8 weeks. The effects of TZP on DN were evaluated by detecting DN-related biochemical indicators, kidney histopathology, apoptosis, OS, and inflammation levels. Additionally, to further reveal the potential mechanism, we investigated the role of TZP in modulating the IL-17 pathway. TZP reduced serum creatinine (sCR), blood urea nitrogen (BUN), and advanced glycosylation end products (AGEs) levels, while simultaneously promoting insulin secretion in diabetic mice. Additionally, TZP attenuated tubular and glomerular injury and reduced renal apoptosis levels. Further studies found that TZP increased the levels of SOD and CAT, and decreased MDA. Meanwhile, TZP also reduced the expression of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) in both mouse serum and kidney homogenates. TZP effectively inhibited the IL-17 pathway, and subsequent intervention with an IL-17 pathway agonist (IL-17A) reversed the suppressive effects of TZP on OS and inflammation. TZP can improve DN by inhibiting OS and inflammation through the suppression of the IL-17 pathway.

Nutritional and functional outcomes in trials of nutrient-stimulated hormone-based therapy-A systematic mapping review

INTRODUCTION

Currently, trials are investigating the efficacy of nutrient-stimulated hormone-based therapies (NuSHs) in promoting weight loss in people living with overweight and obesity. However, the extent to which nutritional and functional outcomes are evaluated remains uncertain. Thus, we conducted a systematic mapping to assess the presence of nutritional and functional outcomes in randomized controlled trials (RCTs) investigating NuSHs.

METHODS

We conducted a systematic mapping search on the Cochrane Central Register of Controlled Trials (CENTRAL), which includes ClinicalTrials.gov and the International Clinical Trials Registry Platform for interventional trials of NuSHs registered from inception to December 31, 2023. We excluded non- and quasi-randomized trials, phase I trials, trials that did not include body weight as a primary or secondary outcome, trials with an intervention duration of less than 6 months, and trials that did not specify a body mass index threshold in their eligibility criteria. Outcomes included: dietary intake, eating behavior, body composition, physical performance, muscle strength, bone health, and levels of vitamins, trace elements, albumin, prealbumin, and hemoglobin.

RESULTS

The search identified 2284 trials, of which 417 were included in the analysis. The proportion of RCTs that included nutritional assessment other than body weight increased over time. Approximately, 20.4% reported measurements of body composition, 17.3% reported measurements of albumin/prealbumin/hemoglobin, and 17% reported assessment of dietary intake and eating behavior. Evaluations of bone health, physical performance, muscle strength, and measurements of vitamins/trace elements were reported in less than 5% of the total trials each.

CONCLUSION

The present review has shown the sparse reporting of nutritional and functional outcomes in RCTs evaluating the impact of NuSHs.

Strategies for minimizing muscle loss during use of incretin-mimetic drugs for treatment of obesity

The rapid and widespread clinical adoption of highly effective incretin-mimetic drugs (IMDs), particularly semaglutide and tirzepatide, for the treatment of obesity has outpaced the updating of clinical practice guidelines. Consequently, many patients may be at risk for adverse effects and uncertain long-term outcomes related to the use of these drugs. Of emerging concern is the loss of skeletal muscle mass and function that can accompany rapid substantial weight reduction; such losses can lead to reduced functional and metabolic health, weight cycling, compromised quality of life, and other adverse outcomes. Available evidence suggests that clinical trial participants receiving IMDs for the treatment of obesity lost 10% or more of their muscle mass during the 68- to 72-week interventions, approximately equivalent to 20 years of age-related muscle loss. The ability to maintain muscle mass during caloric restriction-induced weight reduction is influenced by two key factors: nutrition and physical exercise. Nutrition therapy should ensure adequate intake and absorption of high-quality protein and micronutrients, which may require the use of oral nutritional supplements. Additionally, concurrent physical activity, especially resistance training, has been shown to effectively minimize loss of muscle mass and function during weight reduction therapy. All patients receiving IMDs for obesity should participate in comprehensive treatment programs emphasizing adequate protein and micronutrient intakes, as well as resistance training, to preserve muscle mass and function, maximize the benefit of IMD therapy, and minimize potential risks.

Sleeve gastrectomy plus single anastomosis sleeve ileal bipartition versus sleeve gastrectomy alone: The role of bipartition

BACKGROUND

Sleeve gastrectomy (SG) with single anastomosis sleeve ileal bipartition (SASI) is a novel procedure for increasing the anti-metabolic efficacy of SG in severely people with obesity.

OBJECTIVES

This study aimed to compare 1-year results between SASI and SG, thereby assessing the role of bipartition.

SETTING

The study was conducted at the Medical University hospital.

METHODS

Between November 2021 and December 2022, 39 patients received an SG + SASI surgery, a total of 35 patients completed 1-year follow-up after the surgery. They were matched with a group of 70 patients with SG that were equal in age, sex, and body mass index (BMI). Operative risk, weight loss, and remission of comorbidities were evaluated after 12 months.

RESULTS

The operation time of the SASI group was significantly longer than the SG group (140.3 ± 22.8 vs. 114.9 ± 21.6 min; p < .001). At 12 months after surgery, the SASI group had better weight loss (total weight loss: 37.0% vs. 29.7%; p = .001) and achieved a lower BMI than SG (23.4 ± 2.6 kg/m2 vs. 24.6 ± 2.9 kg/m2; p = .046). Reduction of A1C and remission of T2D was greater in the SASI group. The SASI group had a higher reduction in uric acid, low-density lipoprotein, total cholesterol, and triglyceride levels after operation than the SG group. However, the SG group is superior to the SASI group in mean corpuscular volume, calcium, and iron levels.

CONCLUSIONS

In this study, adding an ileum bipartition to SG increases the weight loss, glycemic, and blood lipid control of SG only.

Reduction of Hepatic Fat Content by Dulaglutide for the Treatment of Diabetes Mellitus: A Two-Centre Open, Single-Arm Trial

BACKGROUND

With the elevated level of NAFLD prevalence, the incidence of diabetes, hypertension, metabolic syndrome and other diseases is also significantly elevated. GLP-1RA can exert weight loss, glucose-lowering effects and various nonglycaemic effects. However, the relationship between quantitative reduction in hepatic fat content and improvement of pancreatic islet function by GLP-1RA is unclear.

METHODS

This trial was a single-arm open cohort study. A total of 38 patients with T2DM and NAFLD were enrolled in the GLP-1RA treatment group. The included patients were tested for biochemical and blood glucose levels, adiponectin and FGF21 levels, and liver fat content was measured using MRI. Measure the above indicators again after at least 3 months of GLP-1RA treatment. Divided into Q1 (average decrease of 0.37%) and Q2 (average decrease of 8.6%) groups based on the degree of reduction in liver fat content.

RESULTS

Q2 group showed an average reduction in liver fat content of 8.6%, a decrease in glycated haemoglobin of 18.17%, a weight loss of 7.29% and an increase in fasting c-peptide release by 1.03%, 1-h and 2-h postprandial c-peptide release by 28.86% and 18.28% respectively. In contrast, Q1 group had an average reduction in liver fat content of 0.37%, a decrease in glycated haemoglobin of only 6.53%, a weight loss of 3.41%, a decrease in fasting c-peptide release by 1.91% and an increase in 1-h and 2-h postprandial c-peptide release by 19.18% and 11.66% respectively.

CONCLUSION

Reduction in liver fat content effectively improves pancreatic islet function secretion, particularly postprandial c-peptide secretion, especially in the first hour after a meal. This improvement leads to a decrease in glycated haemoglobin levels and promotes better compliance with blood glucose control.

Impaired Incretin Homeostasis in Nondiabetic Moderate-to-Severe CKD

Key Points

Total incretin levels and incretin response during oral glucose tolerance testing were significantly higher among patients with moderate-to-severe nondiabetic patients with CKD compared with healthy people. Unlike in healthy individuals, increased incretin response was not correlated with insulin response and coincided with persistently greater glucagon levels to oral glucose tolerance testing in CKD. Disruption in the incretin system and glucagon dynamics may contribute to metabolic complications in moderate-to-severe CKD.

Background

Incretins are regulators of insulin secretion and glucose homeostasis metabolized by dipeptidyl peptidase-4 (DPP-4). CKD may modify incretin release, metabolism, or response.

Methods

We performed 2-hour oral glucose tolerance testing in 59 people with nondiabetic CKD (eGFR <60 ml/min per 1.73 m2) and 39 matched controls. We measured total area under the curve and incremental area under the curve (iAUC) of plasma total glucagon-like peptide-1 (GLP-1) and total glucose-dependent insulinotropic polypeptide (GIP). Fasting DPP-4 levels and activity were measured. Linear regression was used to adjust for demographic, body composition, and lifestyle factors.

Results

Mean (SD) eGFR was 38±13 and 89±17 ml/min per 1.73 m2 in patients with CKD and controls, respectively. GLP-1 total area under the curve and GIP iAUC were higher in patients with CKD than controls with a mean of 1531±1452 versus 1364±1484 pM×min and 62,370±33,453 versus 42,365±25,061 pg×min/ml, respectively. After adjustment, CKD was associated with 15,271 pM×min/ml greater GIP iAUC (95% confidence intervals [CIs], 387 to 30,154) compared with controls. Adjustment for covariates attenuated associations of CKD with higher GLP-1 iAUC (adjusted difference, 122; 95% CI, −619 to 864). Plasma glucagon levels were higher at 30 minutes (mean difference, 1.6; 95% CI, 0.3 to 2.8 mg/dl) and 120 minutes (mean difference, 0.84; 95% CI, 0.2 to 1.5 mg/dl) in patients with CKD compared with controls. There were no differences in insulin levels or plasma DPP-4 activity or levels between groups.

Conclusions

Overall, incretin response to oral glucose is preserved or augmented in moderate-to-severe CKD, without apparent differences in circulating DPP-4 concentration or activity. However, neither insulin secretion nor glucagon suppression is enhanced.

Differential Effects of GLP-1 Receptor Agonists on Cancer Risk in Obesity: A Nationwide Analysis of 1.1 Million Patients

Background: Glucagon-like peptide-1 receptor agonists (GLP-1RAs) have demonstrated significant efficacy in obesity treatment beyond their original development for type-2 diabetes management. This comprehensive study investigated the relationship between GLP-1RA use and cancer incidence in individuals with obesity across a 5-year follow-up period. Methods: We conducted a large-scale cohort study using the TriNetX US Collaborative Network database (2013-2023) examining adult patients with obesity. The study utilized propensity score matching to pair GLP-1RA-treated patients with controls (1:1) using the nearest neighbor method. Cancer incidence served as the primary outcome measure over the 5-year follow-up, with subgroup analyses considering individual GLP-1RA agents, patient sex, and BMI categories. Results: Analysis revealed significant cancer-risk reductions associated with GLP-1RA use across multiple cancer types compared to matched controls. Notable risk reductions were observed in gastrointestinal (HR 0.67, 95% CI 0.59-0.75), skin (HR 0.62, 95% CI 0.55-0.70), breast (HR 0.72, 95% CI 0.64-0.82), female genital (HR 0.61, 95% CI 0.53-0.71), prostate (HR 0.68, 95% CI 0.58-0.80), and lymphoid/hematopoietic cancers (HR 0.69, 95% CI 0.60-0.80). Semaglutide demonstrated superior protective effects, particularly in gastrointestinal cancers (HR 0.45, 95% CI 0.37-0.53). Conversely, liraglutide showed increased risks for thyroid (HR 1.70, 95% CI 1.03-2.82) and respiratory cancers (HR 1.62, 95% CI 1.13-2.32). Conclusions: This research provides compelling evidence for GLP-1RA's potential role in cancer-risk reduction, with semaglutide showing particularly promising results. The differential effects observed among GLP-1RA agents emphasize the importance of personalized medicine approaches. These findings suggest significant implications for clinical practice and future research in both obesity management and cancer prevention.

Food order affects blood glucose and insulin levels in women with gestational diabetes

Background

Gestational diabetes mellitus (GDM) poses significant risks to both maternal and fetal health, including a heightened risk of developing type 2 diabetes (T2DM) in the future. Effective management often involves dietary changes, such as food-order, where vegetables are consumed first, followed by proteins, and then carbohydrates last. This study investigates whether food sequence improves glycemic control in women with GDM by slowing carbohydrate absorption, reducing glucose spikes, and enhancing insulin sensitivity.

Methods

Twenty-five women with GDM participated in a four-week trial with three phases: baseline measurement (week 0), phase 1 (regular diet), and phase 2 (food-order) intervention. Primary outcomes were blood glucose and serum insulin levels, measured at fasting, 1-h, and 2-h postprandial intervals during each phase. In phase 1 (weeks 0-2), participants followed their usual diet. In phase 2 (weeks 2-4), the same participants followed a food-order regimen: vegetables first, then proteins, and carbohydrates last. Customized meal plans for vegetarians and non-vegetarians were provided. Participants were monitored via a mobile application (Jotform) for adherence. Follow-up blood glucose and insulin were measured before, and 60 and 120 min after, consuming a standardized meal (339 kcal, 16.4 g protein, 56.1 g carbohydrates, 3.4 g fat) in the clinic.

Results

The food-order intervention resulted in a significant reduction in postprandial blood glucose by 5.87% (p = 0.001) at 60 min and 6.06% (p = 0.001) at 120 min. Also, Serum insulin levels decreased by 8.13% (p = 0.001) at 60 min and 11.10% (p = 0.001) at 120 min, compared to the regular diet. These results suggest improved metabolic control and insulin sensitivity.

Conclusion

Prioritizing vegetables before protein and carbohydrates improves glycemic control and insulin sensitivity in women with GDM. This simple strategy helps regulate blood glucose and may reduce the long-term risk of T2DM. It offers a practical approach to managing GDM, but further research with larger cohorts and longer interventions is needed to assess its long-term effects.

Clinical trial registration

https://ctri.nic.in/Clinicaltrials/regtrial.php?modid=1&compid=19&EncHid=81473.12293, identifier CTRI/2024/01/061220.

Potential Use of GLP-1 and GIP/GLP-1 Receptor Agonists for Respiratory Disorders: Where Are We at?

Chronic respiratory disorders are the third leading cause of mortality globally. Consequently, there is a continuous pursuit of effective therapies beyond those currently available. The therapeutic potential of the glucagon-like peptide-1 (GLP-1) and the glucose-dependent insulinotropic polypeptide/GLP-1 (GIP/GLP-1) receptor agonists extends beyond the regulation of glycemia, including glucometabolic, cardiovascular, and renal effects, rendering them viable candidates, due to their mechanisms of action, for the possible treatment of respiratory disorders. This manuscript aims to provide a comprehensive evaluation of the evidence on potential direct (cellular) and indirect (metabolic) actions of GLP-1 and GIP/GLP-1 receptor agonists within the pulmonary systems. In addition, it examines their efficacy in addressing prevalent respiratory disorders, specifically chronic obstructive pulmonary disease (COPD), asthma, pneumonia, obstructive sleep apnea, pulmonary hypertension, lung cancer, and lung transplantation. Finally, the manuscript seeks to identify potential avenues for further focused research in this field.

Incretin-based therapy: a new horizon in diabetes management

Diabetes mellitus, a metabolic syndrome characterized by hyperglycemia and insulin dysfunction, often leads to serious complications such as neuropathy, nephropathy, retinopathy, and cardiovascular disease. Incretins, gut peptide hormones released post-nutrient intake, have shown promising therapeutic effects on these complications due to their wide-ranging biological impacts on various body systems. This review focuses on the role of incretin-based therapies, particularly Glucagon-like peptide-1 (GLP-1) agonists and dipeptidyl peptidase-4 (DPP-4) inhibitors, in managing diabetes and its complications. We also discuss the potential of novel agents like semaglutide, a recently approved oral compound, and dual/triple agonists targeting GLP-1/GIP, GLP-1/glucagon, and GLP-1/GIP/glucagon receptors, which are currently under investigation. The review aims to provide a comprehensive understanding of the beneficial impacts of natural incretins and the therapeutic potential of incretin-based therapies in diabetes management.

Enteropancreatic hormone changes in caloric-restricted diet interventions associate with post-intervention weight maintenance

BACKGROUND & AIMS

To explore enteropancreatic hormone changes during isocaloric-restricted dietary interventions and their impact on post-intervention weight maintenance.

METHODS

253 individuals with overweight/obesity and prediabetes were randomly assigned to 25% isocaloric-restricted diets: Control diet, Traditional Jiangnan diet or Mediterranean diet. Serum hormones and clinical indices were evaluated at 0, 3 and 6 months. Body weight values were collected again 6 months after completing interventions.

RESULTS

We observed decreased fasting and post-glucose load levels of glucagon, amylin, peptide YY, and glucagon-like peptide-1 (GLP-1) while increased ghrelin at three months after 25% calorie restriction (CR) of three dietary interventions, and most of these changes were sustained through the six month-treatment period. Interestingly, changes in appetite-inhibitory hormones glucagon, amylin and GLP-1 showed positive associations with body weight change while appetite-promoting hormone ghrelin showed an inverse association during intervention. Furthermore, subjects with more reduction in amylin and GLP-1, or more increase in ghrelin during intervention showed a greater increase in body weight after completing intervention.

CONCLUSIONS

CR intervention results in consistent hormone signatures regardless of dietary patterns. More changes in amylin, GLP-1 or ghrelin levels during CR are associated with poor weight maintenance after intervention, supporting that CR-induced hormone changes as biomarkers for predicting weight maintenance after intervention.

TRIAL REGISTRATION

Clinicaltrials.gov NCT03856762.

Effect of tirzepatide on the progression of coronary atherosclerosis using MDCT: Rationale and design of the tirzepatide treatment on coronary atherosclerosis progression: The (T-Plaque) randomized-controlled trial design

INTRODUCTION

Tirzepatide is a novel once-week dual GIP/GLP-1 RA agonist approved for T2DM and its role to reduce cardiovascular events remains to be elucidated. The goal of this trial is to assess how tirzepatide affects the progression of atherosclerotic plaque as determined by multidetector computed tomography angiography (MDCTA).

METHODS

This trial is a double blind, randomized, prospective, placebo-controlled multicenter phase IV trial. Participant eligible for the study will be adults with T2DM between 40 and 80 years of age who have HbA1c ≥ 7.0% to ≤ 10.5% and at least 20% stenosis in major epicardial vessel on CCTA. Baseline examination will include the results of their demographics, lab tests, coronary calcium, as well as coronary plaque volume/composition. Following randomization, tirzepatide or placebo will be given at a weekly dose of 2.5 mg, and a fixed dose-escalation strategy will be followed. Patients will undergo quarterly visits for safety assessments and labs, and follow up with repeat CCTA at 1 year.

DISCUSSION

This study evaluates the antiatherogenic potential of tirzepatide, providing a mechanism of potential CV benefit. This is crucial to our understanding of T2DM treatment and CVD since plaque progression portends worse outcomes in these populations. MDCTA is a noninvasive method that assesses the volume, composition, and degree of coronary vessel stenosis.

CONCLUSION

This study will be the first study to assess the effects of tirzepatide on atherosclerotic plaque progression measured by MDCTA in participants with T2DM.

Incretin impact on gastric function in obesity: physiology, and pharmacological, surgical and endoscopic treatments

The aims of this review are to appraise the role of the stomach in satiation, the effects of incretin and other hormone agonists on weight loss and the role of altered gastric functions in their effects on obesity or glycaemic control. In addition to the gut in its role in enzymatic digestion and hormonal responses to nutrient ingestion, gastric motor functions include accommodation, trituration and emptying [gastric emptying (GE)] of food and elicitation of postprandial satiation and satiety. The postprandially released hormones most extensively studied and utilized therapeutically are glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP). Their mechanisms of action include stimulation of pancreatic β cells to produce insulin. However, GLP-1 reduces glucagon and slows GE, whereas GIP increases glucagon and does not alter GE. Molecular modifications of GLP-1 (which has a T1/2 of 3 min) led to the development of long-acting subcutaneous or oral pharmacological agents that have been approved for the treatment of obesity, and their effects on gastric function are documented. Other medications in development target other molecular mechanisms, including glucagon and amylin. Small-molecule GLP-1 receptor agonists are promising for the treatment of obesity and may also slow GE. Bariatric surgery and endoscopy increase satiation by restricting gastric size; in addition Roux-en-Y gastric bypass and to a lesser extent sleeve gastrectomy (but not endoscopic gastroplasty) increase postprandial circulating incretins, reducing appetite. In conclusion the stomach's function is integral to the impact of the most effective pharmacological and procedural reversal of obesity related to the incretin revolution.

Effects of Tirzepatide vs Semaglutide on β-Cell Function, Insulin Sensitivity, and Glucose Control During a Meal Test

CONTEXT

In a clinical study, tirzepatide, a glucose-dependent insulinotropic polypeptide/glucagon-like peptide-1 receptor agonist (GIP/GLP-1RA), provided superior glycemic control vs the GLP-1RA semaglutide. The physiologic mechanisms are incompletely understood.

OBJECTIVE

This work aimed to evaluate treatment effects by model-based analyses of mixed-meal tolerance test (MMTT) data.

METHODS

A 28-week double-blind, randomized, placebo-controlled trial of patients with type 2 diabetes treated with metformin was conducted at 2 clinical research centers in Germany. Interventions included tirzepatide 15 mg, semaglutide 1 mg, and placebo. Main outcome measures included glycemic control, model-derived β-cell function indices including insulin secretion rate (ISR) at 7.2-mmol/L glucose (ISR7.2), β-cell glucose sensitivity (β-CGS), insulin sensitivity, and estimated hepatic insulin-to-glucagon ratio.

RESULTS

Tirzepatide significantly reduced fasting glucose and MMTT total glucose area under the curve (AUC) vs semaglutide (P < .01). Incremental glucose AUC did not differ significantly between treatments; therefore, greater total glucose AUC reduction with tirzepatide was mainly attributable to greater suppression of fasting glucose. A greater reduction in total ISR AUC was achieved with tirzepatide vs semaglutide (P < .01), in the context of greater improvement in insulin sensitivity with tirzepatide (P < .01). ISR7.2 was significantly increased with tirzepatide vs semaglutide (P < .05), showing improved β-CGS. MMTT-derived β-CGS was increased but not significantly different between treatments. Both treatments reduced fasting glucagon and total glucagon AUC, with glucagon AUC significantly reduced with tirzepatide vs semaglutide (P < .01). The estimated hepatic insulin-to-glucagon ratio did not change substantially with either treatment.

CONCLUSION

These results suggest that the greater glycemic control observed for tirzepatide manifests as improved fasting glucose and glucose excursion control, due to improvements in ISR, insulin sensitivity, and glucagon suppression.

Dramatic Changes in Thiopurine Metabolite Levels in a Patient With Inflammatory Bowel Disease Treated With Tirzepatide for Weight Loss

Thiopurines can be used to maintain remission in patients with inflammatory bowel disease. Thiopurines require regular blood count monitoring and, in specific patients, thiopurine metabolites for assessment of optimization and safety. We present the case of a 42-year-old woman with ulcerative colitis postcolectomy and ileal pouch-anal anastomosis with subsequent antibiotic-resistant diffuse pouchitis and prepouch ileitis. She was in stable remission with thiopurine monotherapy. Following tirzepatide initiation, she experienced elevated liver enzymes associated with a significant increase in thiopurine metabolite levels. This case underlines the importance of monitoring metabolite levels in patients with inflammatory bowel disease initiated on glucagon-like peptide 1-targeted therapies.

Incretin-Based Therapies: A Promising Approach for Modulating Oxidative Stress and Insulin Resistance in Sarcopenia

BACKGROUND

Recent studies have linked sarcopenia development to the hallmarks of diabetes, oxidative stress, and insulin resistance. The anti-oxidant and insulin sensitivityenhancing effects of incretin-based therapies may provide a promising option for the treatment of sarcopenia. This review aimed to unveil the role of oxidative stress and insulin resistance in the pathogenesis of sarcopenia and explore the potential benefits of incretin-based therapies in individuals with sarcopenia.

METHODS

PubMed, the Cochrane Library, and Google Scholar databases were searched by applying keywords relevant to the main topic, to identify articles that met our selection criteria.

RESULTS

Incretin-based therapies manifested anti-oxidant effects by increasing the anti-oxidant defense system and decreasing free radical generation or by indirectly minimizing glucotoxicity, which was mainly achieved by improving insulin signaling and glucose homeostasis. Likewise, these drugs exhibit insulin-sensitizing activities by increasing insulin secretion, transduction, and β-cell function or by reducing inflammation and lipotoxicity.

CONCLUSIONS

Incretin-based therapies, as modulators of oxidation and insulin resistance, may target the main pathophysiological factors of sarcopenia, thus providing a promising strategy for the treatment of this disease.

The influence of insulin and incretin-based therapies on renal tubular transport

The tubular function of the kidney is very complex and is finely regulated by many factors. These include a variety of hormonal signaling pathways which are involved in the expression, activation and regulation of renal transporters responsible for the handling of electrolytes. Glucose-lowering drugs such as insulin and incretin-based therapies, exert a well-known renal protective role in diabetic kidney disease, mainly acting at the glomerular level. In the literature, several studies have described the effect of insulin and the incretin hormones on tubular transport. Most of these studies focused on the variations in excretion and clearance of sodium but did not extensively and systematically investigate the possible variations that these hormones may induce in the tubular regulation of all the other electrolytes, urea metabolism, acid-base balance and urinary pH. While insulin action on the kidney is very well-described, the renal tubular impact of incretin-based therapies is less consistent and the results available are scarce. To our knowledge, this is the first review summarizing the effects induced on renal tubules by insulin, glucagon-like peptide-1 (GLP-1) receptor agonists and serine protease dipeptidyl peptidase-4 (DPP4) inhibitors in both healthy and diabetic human subjects. This is significant because it highlights the existence of a renal-gut and pancreas axis which also has a direct tubular effect and enables a deeper understanding of renal physiology.

Changes in 24-Hour Urine Chemistry in Patients with Nephrolithiasis during Weight Loss with Glucagon-Like Peptide 1-Based Therapies

Key Points

Background

Obesity is an independent risk factor of incident and recurrent nephrolithiasis. The effect of weight loss through glucagon-like peptide 1 (GLP-1) receptor agonists and dual GLP-1/gastric inhibitory polypeptide receptor agonists (GLP-based therapies) on nephrolithiasis is not well understood. This study examined the changes in 24-hour urine chemistry assessing for stone risk during weight loss through GLP-based therapies.

Methods

This retrospective analysis identified adult stone formers followed at our academic institution's weight wellness clinic between September 2015 and August 2023 and included patients with at least two 24-hour urine collections for stone risk assessment. 24-hour urine parameters before and during weight loss in patients on GLP-based therapies were compared.

Results

Forty-four obese patients with nephrolithiasis experienced significant weight reduction (−6.6±7.3 kg, P < 0.001) over a median 1.1 years of follow-up with GLP-based therapies. During this period, there was a significant decrease in 24-hour urine oxalate (40±16 to 32±11 mg/d, P = 0.002), sulfate (21±10 to 17±9 mmol/d, P = 0005), and ammonium (35±22 to 29±15 mEq/d, P = 0.01) excretion rates. There were nonsignificant changes in urine calcium, citrate, uric acid, pH, phosphorus, sodium, potassium, magnesium, chloride, creatinine, or total volume. In addition, there was no statistical difference in urine supersaturation indices with respect to calcium oxalate, calcium phosphate, and uric acid.

Conclusions

Our results indicate that weight loss through GLP-based therapies is not associated with prolithogenic changes in 24-hour urine chemistry in patients with nephrolithiasis, unlike what happens with other weight loss modalities.

Anti-atherosclerotic effect of incretin receptor agonists

Incretin receptor agonists (IRAs), primarily composed of glucagon-like peptide-1 receptor agonists (GLP-1RAs) and glucose-dependent insulinotropic polypeptide receptor agonists (GIPRAs), work by mimicking the actions of the endogenous incretin hormones in the body. GLP-1RAs have been approved for use as monotherapy and in combination with GIPRAs for the management of type 2 diabetes mellitus (T2DM). In addition to their role in glucose regulation, IRAs have demonstrated various benefits such as cardiovascular protection, obesity management, and regulation of bone turnover. Some studies have suggested that IRAs not only aid in glycemic control but also exhibit anti-atherosclerotic effects. These agents have been shown to modulate lipid abnormalities, reduce blood pressure, and preserve the structural and functional integrity of the endothelium. Furthermore, IRAs have the ability to mitigate inflammation by inhibiting macrophage activation and promoting M2 polarization. Research has also indicated that IRAs can decrease macrophage foam cell formation and prevent vascular smooth muscle cell (VSMC) phenotype switching, which are pivotal in atheromatous plaque formation and stability. This review offers a comprehensive overview of the protective effects of IRAs in atherosclerotic disease, with a focus on their impact on atherogenesis.

Tirzepatide, GIP(1-42) and GIP(1-30) display unique signaling profiles at two common GIP receptor variants, E354 and Q354

Type 2 diabetes (T2D) and obesity are prevalent metabolic disorders affecting millions of individuals worldwide. A new effective therapeutic drug called tirzepatide for the treatment of obesity and T2D is a dual agonist of the GIP receptor and GLP-1 receptor. Tirzepatide is clinically more effective than GLP-1 receptor agonists but the reasons why are not well understood. Tirzepatide reportedly stimulates the GIP receptor more potently than the GLP-1 receptor. However, tirzepatide signaling has not been thoroughly investigated at the E354 (wildtype) or Q354 (E354Q) GIP receptor variants. The E354Q variant is associated increased risk of T2D and lower body mass index. To better understand GIP receptor signaling we characterized the activity of endogenous agonists and tirzepatide at both GIP receptor variants. Using Cos7 cells we examined wildtype and E354Q GIP receptor signaling, analyzing cAMP and IP1 accumulation as well as AKT, ERK1/2 and CREB phosphorylation. GIP(1-42) and GIP(1-30)NH2 displayed equipotent effects on these pathways excluding CREB phosphorylation where GIP(1-30)NH2 was more potent than GIP(1-42) at the E354Q GIP receptor. Tirzepatide favored cAMP signaling at both variants. These findings indicate that tirzepatide is a biased agonist towards Gαs signaling and suggests it equally activates the wildtype and E354Q GIP receptor variants. We also observed differences between the pharmacology of the GIP receptor variants with endogenous peptides, which may help to explain differences in phenotype. These findings contribute to a comprehensive understanding of GIP receptor signaling, and will aid development of therapies combating T2D and obesity.

Non-functional alpha-cell hyperplasia with glucagon-producing NET: a case report

Introduction

Alpha-cell hyperplasia (ACH) is a rare pancreatic endocrine condition. Three types of ACH have been described: functional or nonglucagonoma hyperglucagonemic glucagonoma syndrome, reactive or secondary to defective glucagon signaling, and non-functional. Few cases of ACH with concomitant pancreatic neuroendocrine tumors (pNETs) have been reported and its etiology remains poorly understood. A case report of non-functional ACH with glucagon-producing NET is herein presented.

Case report

A 72-year-old male was referred to our institution for a 2 cm single pNET incidentally found during imaging for acute cholecystitis. The patient's past medical history included type 2 diabetes (T2D) diagnosed 12 years earlier, for which he was prescribed metformin, dapagliflozin, and semaglutide. The pNET was clinically and biochemically non-functioning, apart from mildly elevated glucagon 217 pg/ml (<209), and 68Ga-SSTR PET/CT positive uptake was only found at the pancreatic tail (SUVmax 11.45). The patient underwent a caudal pancreatectomy and the post-operative 68Ga-SSTR PET/CT was negative. A multifocal well-differentiated NET G1, pT1N0M0R0 (mf) strongly staining for glucagon on a background neuroendocrine alpha-cell hyperplasia with some degree of acinar fibrosis was identified on pathology analysis.

Discussion and conclusion

This case reports the incidental finding of a clinically non-functioning pNET in a patient with T2D and elevated glucagon levels, unexpectedly diagnosed as glucagon-producing NET and ACH. A high level of suspicion was required to conduct the glucagon immunostaining, which is not part of the pathology routine for a clinically non-functioning pNET, and was key for the diagnosis that otherwise would have been missed. This case highlights the need to consider the diagnosis of glucagon-producing pNET on an ACH background even in the absence of glucagonoma syndrome.

Dietary intake by patients taking GLP-1 and dual GIP/GLP-1 receptor agonists: A narrative review and discussion of research needs

Background

Obesity and type 2 diabetes mellitus (T2DM) are increasingly common in the United States and worldwide. Because both conditions are associated with serious health consequences, weight reduction is recommended by professional medical and nutrition societies to improve outcomes. Due to the striking efficacy of glucagon-like peptide receptor agonists (GLP-1RAs) and dual mechanism glucose-dependent insulinotropic polypeptide/glucagon-like peptide receptor agonists (GIP/GLP-1RAs) for weight reduction and glycemic control, there is increased utilization for patients with obesity and/or T2DM. Yet, the impact of these medications on dietary intake is less understood.

Methods

This narrative literature review summarizes clinical studies quantifying and characterizing dietary intake in people with obesity and/or T2DM using GLP-1 or GIP/GLP-1 RAs.

Results

Though data from these studies reveal that total caloric intake was reduced by 16-39 %, few studies evaluated the actual composition of the diet.

Conclusions

Further research is needed to understand the unique nutritional needs of adults on GLP-1 or dual GIP/GLP-1RAs and to support the development of nutritional guidelines for these individuals.

Racial Comparison of the Pharmacokinetics and Safety of Fixed-dose Combination of Dapagliflozin/Sitagliptin in Western and Korean Healthy Adults

PURPOSE

We evaluated the pharmacokinetics, safety, and tolerability of a fixed-dose combination (FDC) of dapagliflozin/sitagliptin versus individual component (IC) tablets in healthy Western and Korean participants. The combination of these antihyperglycemic drugs provides efficient glucose control, and the use of FDC has generally been shown to improve medication adherence in individuals with type 2 diabetes mellitus (T2DM).

METHODS

Two randomized, open-label, two-period, two-treatment, single-dose, single-center, crossover bioequivalence studies conducted on healthy fasted German participants (aged 18-55 years; Western study) and South Korean participants (aged 19-55 years; Korean study) were included. In both studies, pharmacokinetic parameters (maximum [peak] plasma concentration [Cmax], area under the plasma concentration-time curve from zero to the last quantifiable concentration [AUClast], and area under the plasma concentration-time curve from zero to infinity [AUCinf]) were used to assess the bioequivalence of 10 mg dapagliflozin/100 mg sitagliptin FDC (Treatment A) with their ICs (Treatment B) under fasted conditions. Safety and tolerability were assessed throughout the study.

FINDINGS

Forty-six healthy participants (male, 60.9%; mean age, 39.5 years; mean body mass index [BMI], 23.9 kg/m2) were randomized in the Western study, and 51 healthy participants (male, 100.0%; mean age, 24.6 years; mean BMI, 23.9 kg/m2) were randomized in the Korean study. In both studies, the participants were randomized 1:1 into treatment sequence AB and treatment sequence BA. Dapagliflozin/sitagliptin FDC was bioequivalent to IC tablets in both Western and Korean studies, as the 90% confidence interval of the FDC to IC ratios of the geometric least-squares means of the pharmacokinetic parameters for both dapagliflozin and sitagliptin was within the 0.8000-1.2500 bioequivalence criterion limit. The observed differences in pharmacokinetic parameters, such as Cmax, AUClast, and AUCinf, between the Western and Korean studies were not clinically meaningful. Dapagliflozin/sitagliptin FDC and their ICs were well tolerated, with no serious adverse events reported in any of the study populations.

IMPLICATIONS

The 10 mg dapagliflozin/100 mg sitagliptin FDC and IC formulations were bioequivalent in fasted healthy Western and Korean participants, with no new safety concerns identified, thus offering a useful alternative for patients currently receiving individual medications as part of their treatment regimen.

CLINICAL TRIAL REGISTRATION

Western study (clinicaltrials.gov: NCT05266404) and Korean study (clinicaltrials.gov: NCT05453786).

Advances in small-molecule insulin secretagogues for diabetes treatment

Diabetes, a metabolic disease caused by abnormally high levels of blood glucose, has a high prevalence rate worldwide and causes a series of complications, including coronary heart disease, stroke, peripheral vascular disease, end-stage renal disease, and retinopathy. Small-molecule compounds have been developed as drugs for the treatment of diabetes because of their oral advantages. Insulin secretagogues are a class of small-molecule drugs used to treat diabetes, and include sulfonylureas, non-sulfonylureas, glucagon-like peptide-1 receptor agonists, dipeptidyl peptidase 4 inhibitors, and other novel small-molecule insulin secretagogues. However, many small-molecule compounds cause different side effects, posing huge challenges to drug monotherapy and drug selection. Therefore, the use of different small-molecule drugs must be improved. This article reviews the mechanism, advantages, limitations, and potential risks of small-molecule insulin secretagogues to provide future research directions on small-molecule drugs for the treatment of diabetes.

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.

Long-term Metabolic Dysfunction Programming in Female Mice by Serial Moderate Restriction of a High-fat High-sucrose Diet

BACKGROUND

While intermittent fasting leads to weight loss and improved glucose metabolism, food insecurity, the insufficient access to food for a healthy life, is associated with obesity and adverse cardiometabolic health, especially in women. We aimed to characterize the effects of intermittently restricted feeding on energy balance and glucose tolerance in female mice.

METHODS

Female C57BL/6J mice were fed a high-fat, high-sucrose diet and intermittently food restricted to 60% of control littermates' ad libitum intake, starting at weaning and until week 19. Restricted mice were subsequently allowed ad libitum access to the same diet. Body composition and energy balance were measured at weeks 18.5, 19, 30, and 40. At week 42, mice underwent an intraperitoneal glucose tolerance test and plasma appetitive hormones measurements after nutrient gavage.

RESULTS

During the food restriction phase, restricted mice accrued lower weight and fat mass than controls despite periodic ad libitum food access. Reintroduction of continuous ad libitum food caused increased food intake during the light phase and increased body mass in restricted mice. Minor differences in body composition-adjusted energy expenditure between groups were observed at week 40. At week 42, glucose tolerance was impaired in restricted mice compared to controls, and trends toward lower levels of postprandial anorexigenic hormones glucagon-like peptide-1 and pancreatic polypeptide were observed.

CONCLUSION

Our findings suggest that repeated intermittent food restriction leads to changes in eating behavior that predispose to glucose intolerance when food is freely available. Future studies are needed to elucidate the specific mechanisms underlying these changes.

Team players in the pathogenesis of metabolic dysfunctions-associated steatotic liver disease: The basis of development of pharmacotherapy

Nutrient metabolism is regulated by several factors. Social determinants of health with or without genetics are the primary regulator of metabolism, and an unhealthy lifestyle affects all modulators and mediators, leading to the adaptation and finally to the exhaustion of cellular functions. Hepatic steatosis is defined by presence of fat in more than 5% of hepatocytes. In hepatocytes, fat is stored as triglycerides in lipid droplet. Hepatic steatosis results from a combination of multiple intracellular processes. In a healthy individual nutrient metabolism is regulated at several steps. It ranges from the selection of nutrients in a grocery store to the last step of consumption of ATP as an energy or as a building block of a cell as structural component. Several hormones, peptides, and genes have been described that participate in nutrient metabolism. Several enzymes participate in each nutrient metabolism as described above from ingestion to generation of ATP. As of now several publications have revealed very intricate regulation of nutrient metabolism, where most of the regulatory factors are tied to each other bidirectionally, making it difficult to comprehend chronological sequence of events. Insulin hormone is the primary regulator of all nutrients' metabolism both in prandial and fasting states. Insulin exerts its effects directly and indirectly on enzymes involved in the three main cellular function processes; metabolic, inflammation and repair, and cell growth and regeneration. Final regulators that control the enzymatic functions through stimulation or suppression of a cell are nuclear receptors in especially farnesoid X receptor and peroxisome proliferator-activated receptor/RXR ligands, adiponectin, leptin, and adiponutrin. Insulin hormone has direct effect on these final modulators. Whereas blood glucose level, serum lipids, incretin hormones, bile acids in conjunction with microbiota are intermediary modulators which are controlled by lifestyle. The purpose of this review is to overview the key players in the pathogenesis of metabolic dysfunction-associated steatotic liver disease (MASLD) that help us understand the disease natural course, risk stratification, role of lifestyle and pharmacotherapy in each individual patient with MASLD to achieve personalized care and target the practice of precision medicine. PubMed and Google Scholar databases were used to identify publication related to metabolism of carbohydrate and fat in states of health and disease states; MASLD, cardiovascular disease and cancer. More than 1000 publications including original research and review papers were reviewed.

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.

The central role of the gut microbiota in the pathophysiology and management of type 2 diabetes

The inhabitants of our intestines, collectively called the gut microbiome, comprise fungi, viruses, and bacterial strains. These microorganisms are involved in the fermentation of dietary compounds and the regulation of our adaptive and innate immune systems. Less known is the reciprocal interaction between the gut microbiota and type 2 diabetes mellitus (T2DM), as well as their role in modifying therapies to reduce associated morbidity and mortality. In this review, we aim to discuss the existing literature on gut microbial strains and their diet-derived metabolites involved in T2DM. We also explore the potential diagnostics and therapeutic avenues the gut microbiota presents for targeted T2DM management. Personalized treatment plans, driven by diet and medication based on the patient's microbiome and clinical markers, could optimize therapy.

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.

Obesity treatment in adolescents and adults in the era of personalized medicine

In this multi-professional review, we will provide the in-depth knowledge required to work in the expanding field of obesity treatment. The prevalence of obesity has doubled in adults and quadrupled in children over the last three decades. The most common treatment offered has been lifestyle treatment, which has a modest or little long-term effect. Recently, several new treatment options-leading to improved weight loss-have become available. However, long-term care is not only about weight loss but also aims to improve health and wellbeing overall. In the era of personalized medicine, we have an obligation to tailor the treatment in close dialogue with our patients. The main focus of this review is new pharmacological treatments and modern metabolic surgery, with practical guidance on what to consider when selecting and guiding the patients and what to include in the follow-up care. Furthermore, we discuss common clinical challenges, such as patients with concurrent eating disorder or mental health problems, and treatment in the older adults. We also provide recommendations on how to deal with obesity in a non-stigmatizing way to diminish weight stigma during treatment. Finally, we present six microcases-obesity treatment for persons with neuropsychiatric disorders and/or intellectual disability; obesity treatment in the nonresponsive patient who has "tried everything"; and hypoglycemia, abdominal pain, and weight regain after metabolic surgery-to highlight common problems in weight-loss treatment and provide personalized treatment suggestions.

Effect of preceding drug therapy on the renal and cardiovascular outcomes of combined sodium-glucose cotransporter-2 inhibitor and glucagon-like peptide-1 receptor agonist treatment in patients with type 2 diabetes and chronic kidney disease

AIM

To conduct a post hoc subgroup analysis of patients with type 2 diabetes (T2D) from the RECAP study, who were treated with sodium-glucose cotransporter-2 (SGLT2) inhibitor and glucagon-like peptide 1 receptor agonist (GLP-1RA) combination therapy, focusing only on those patients who had chronic kidney disease (CKD), to examine whether the composite renal outcome differed between those who received SGLT2 inhibitor treatment first and those who received a GLP-1RA first.

METHODS

We included 438 patients with CKD (GLP-1RA-first group, n = 223; SGLT2 inhibitor-first group, n = 215) from the 643 T2D patients in the RECAP study. The incidence of the composite renal outcome, defined as progression to macroalbuminuria and/or a ≥50% decrease in estimated glomerular filtration rate (eGFR), was analysed using a propensity score (PS)-matched model. Furthermore, we calculated the win ratio for these composite renal outcomes, which were weighted in the following order: (1) both a ≥50% decrease in eGFR and progression to macroalbuminuria; (2) a decrease in eGFR of ≥50% only; and (3) progression to macroalbuminuria only.

RESULTS

Using the PS-matched model, 132 patients from each group were paired. The incidence of renal composite outcomes did not differ between the two groups (GLP-1RA-first group, 10%; SGLT2 inhibitor-first group, 17%; odds ratio 1.80; 95% confidence interval [CI] 0.85 to 4.26; p = 0.12). The win ratio of the GLP-1RA-first group versus the SGLT2 inhibitor-first group was 1.83 (95% CI 1.71 to 1.95; p < 0.001).

CONCLUSION

Although the renal composite outcome did not differ between the two groups, the win ratio of the GLP-1RA-first group versus the SGLT2 inhibitor-first group was significant. These results suggest that, in GLP-1RA and SGLT2 inhibitor combination therapy, the addition of an SGLT2 inhibitor to baseline GLP-1RA treatment may lead to more favourable renal outcomes.

Bridging the gap between GLP1-receptor agonists and cardiovascular outcomes: evidence for the role of tirzepatide

Tirzepatide is a new drug targeting glucagon-like peptide 1(GLP1) and gastric inhibitory polypeptide (GIP) receptors. This drug has demonstrated great potential in improving the clinical outcomes of patients with type 2 diabetes. It can lead to weight loss, better glycemic control, and reduced cardiometabolic risk factors. GLP1 receptor agonists have been proven effective antidiabetic medications with possible cardiovascular benefits. Even though they have been proven to reduce the risk of major adverse cardiovascular events, their effectiveness in treating heart failure is unknown. Unlike traditional GLP1 receptor agonists, tirzepatide is more selective for the GIP receptor, resulting in a more balanced activation of these receptors. This review article discusses the possible mechanisms tirzepatide may use to improve cardiovascular health. That includes the anti-inflammatory effect, the ability to reduce cell death and promote autophagy, and also its indirect effects through blood pressure, obesity, and glucose/lipid metabolism. Additionally, tirzepatide may benefit atherosclerosis and lower the risk of major adverse cardiac events. Currently, clinical trials are underway to evaluate the safety and efficacy of tirzepatide in patients with heart failure. Overall, tirzepatide's dual agonism of GLP1 and GIP receptors appears to provide encouraging cardiovascular benefits beyond glycemic control, offering a potential new therapeutic option for treating cardiovascular diseases and heart failure.

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.

Short-term high-calorie high-fat feeding induces hyperinsulinemia and blunts skeletal muscle microvascular blood flow in healthy humans

Skeletal muscle microvascular blood flow (MBF) plays an important role in glucose disposal in muscle. Impairments in muscle MBF contribute to insulin resistance and prediabetes. Animal studies show that short-term (3 day) high-fat feeding blunts skeletal muscle MBF before impairing insulin-stimulated glucose disposal. It is not known whether this occurs in humans. We investigated the temporal impact of a 7-day high-calorie high-fat (HCHF) diet intervention (+52% kJ; 41% fat) on fasting and postprandial cardiometabolic outcomes in 14 healthy adults (18-37 yr). Metabolic health and vascular responses to a mixed-meal challenge (MMC) were measured at pre (day 0)-, mid (day 4)- and post (day 8)-intervention. There were no significant differences in body weight, body fat %, fasting blood glucose, and fasting plasma insulin concentrations at pre-, mid- and postintervention. Compared with preintervention there was a significant increase in insulin (but not glucose) total area under the curve in response to the MMC at midintervention (P = 0.041) and at postintervention (P = 0.028). Unlike at pre- and midintervention, at postintervention muscle MBF decreased at 60 min (P = 0.024) and 120 min (P = 0.023) after the MMC. However, macrovascular blood flow was significantly increased from 0 to 60 min (P < 0.001) and 120 min (P < 0.001) after the MMC at pre-, mid- and postintervention. Therefore, short-term HCHF feeding in healthy individuals leads to elevated postprandial insulin but not glucose levels and a blunting of meal-induced skeletal muscle MBF responses but not macrovascular blood flow responses.NEW & NOTEWORTHY This is the first study to investigate skeletal muscle microvascular blood flow (MBF) responses in humans after short-term high-calorie high-fat (HCHF) diet. The main findings were that HCHF diet causes elevated postprandial insulin in healthy individuals within 3 days and blunts meal-induced muscle MBF within 7 days, despite no impairments in postprandial glucose or macrovascular blood flow.

Modulation of gut microbiota by crude gac aril polysaccharides ameliorates diet-induced obesity and metabolic disorders

Obesity is a global health challenge that causes metabolic dysregulation and increases the risk of various chronic diseases. The gut microbiome is crucial in modulating host energy metabolism, immunity, and inflammation and is influenced by dietary factors. Gac fruit (Momordica cochinchinensis), widely consumed in Southeast Asia, has been proven to have various biological activities. However, the composition and effect of crude gac aril polysaccharides (GAP) on obesity and gut microbiota disturbed by high-fat diet (HFD) remain to be elucidated. Compositional analysis showed that GAP contains high oligosaccharides, with an average of 7-8 saccharide units. To mimic clinical obesity, mice were first made obese by feeding HFD for eight weeks. GAP intervention was performed from week 9 to week 20 in HFD-fed mice. Our results showed that GAP inhibited body weight gain, eWAT adipocyte hypertrophy, adipokine derangement, and hyperlipidemia in HFD-induced obese mice. GAP improved insulin sensitivity, impaired glucose tolerance, and hepatic steatosis. GAP modulated the gut microbiota composition and reversed the HFD-induced dysbiosis of at least 20 genera. Taken together, GAP improves metabolic health and modulates the gut microbiome to relieve obesity risk factors, demonstrating the potential of dietary GAP for treating obesity-associated disorders.

Glucagon-like peptide-1 receptor agonists: a narrative review of clinical pharmacology and implications for peri-operative practice

BACKGROUND

Glucagon-like peptide-1 receptor agonists are used increasingly in the management of patients living with type 2 diabetes mellitus and obesity. In patients using glucagon-like peptide-1 receptor agonists, a key concern in the peri-operative period is the increased risk of pulmonary aspiration due to delayed gastric emptying. This review provides an overview of the pharmacodynamic and pharmacokinetic properties of glucagon-like peptide-1 receptor agonists and the risk of delayed gastric emptying and aspiration.

METHODS

We conducted searches of MEDLINE and EMBASE databases of articles published before January 2024 using the keywords and medical subject headings: incretins; glucagon-like peptide-1; GLP-1; glucagon-like peptide-1 receptor agonists; GLP-1 RA; peri-operative period; perioperative; peri-operative; stomach emptying; gastric emptying; pulmonary aspiration; aspiration; food regurgitation; and regurgitation. The evidence was analysed, synthesised and reported narratively.

RESULTS

A total of 1213 articles were located after duplicates were removed. Two authors screened the titles and abstracts to identify those studies which assessed specifically the risk of delayed gastric emptying and pulmonary aspiration or regurgitation in the peri-operative period. We searched manually the reference lists of relevant studies to identify any additional case reports. Ten studies were identified. Available evidence was limited to case reports, case series and observational work.

CONCLUSIONS

There is insufficient evidence to put forward definitive guidance regarding the ideal cessation period for glucagon-like peptide-1 receptor agonists before elective surgery. Precautionary practice is required until more evidence becomes available. We suggest an individualised, evidence-based approach. In patients living with type 2 diabetes mellitus, there is concern that prolonged cessation before surgery will have a detrimental effect on peri-operative glycaemic control and discussion with an endocrinologist is advised. For patients taking glucagon-like peptide-1 receptor agonists for weight management, these drugs should be withheld for at least three half-lives before an elective surgical procedure.

Tirzepatide against obesity and insulin-resistance: pathophysiological aspects and clinical evidence

Obesity is a chronic, multifactorial disease in which accumulated excess body fat has a negative impact on health. Obesity continues to rise among the general population, resulting in an epidemic that shows no significant signs of decline. It is directly involved in development of cardiometabolic diseases, ischemic coronary heart disease peripheral arterial disease, heart failure, and arterial hypertension, producing global morbidity and mortality. Mainly, abdominal obesity represents a crucial factor for cardiovascular illness and also the most frequent component of metabolic syndrome. Recent evidence showed that Tirzepatide (TZP), a new drug including both Glucagon Like Peptide 1 (GLP-1) and Glucose-dependent Insulinotropic Polypeptide (GIP) receptor agonism, is effective in subjects with type 2 diabetes (T2D), lowering body weight, fat mass and glycated hemoglobin (HbA1c) also in obese or overweight adults without T2D. This review discusses the pathophysiological mechanisms and clinical aspects of TZP in treating obesity.

Hormone imbalances detected in study participants with pre-diabetes in a Durban-based clinical setting, South Africa

Background

Type II diabetes mellitus onset is linked with hormonal imbalances. However, the knowledge about hormonal alterations in pre-diabetes is limited.

Objective

The study aimed to examine type II diabetes mellitus-associated hormone levels during the pre-diabetes phase in participants aged 25–45 in a Durban-based clinical setting in South Africa.

Methods

Stored plasma samples from a retrospective study collected 364 samples that were divided into pre-diabetes and non-pre-diabetes groups. From the 364, 38 samples from the group of persons without pre-diabetes and 38 from persons with glycated haemoglobin determined pre-diabetes were blindly selected. The hormone concentrations (C-peptide, cortisol, adipokines, thyroids, incretins, and sex steroids) of the study participants were measured using the BIO-RAD Bio-Plex MAGPIX instrument.

Results

Hormone imbalances in several hormones were detected in study participants with pre-diabetes. Most of the hormone dysregulation associated with T2DM begins in pre-diabetes but at a moderate level.

Conclusion

The findings reveal new possible hormone therapy targets for pre-diabetes and contribute to the growing support for targeting pre-diabetes as a preventative measure for T2DM prevention.

Intestinal alterations and mild glucose homeostasis impairments in the offspring born to overweight rats

The gut plays a crucial role in metabolism by regulating the passage of nutrients, water and microbial-derived substances to the portal circulation. Additionally, it produces incretins, such as glucose-insulinotropic releasing peptide (GIP) and glucagon-like derived peptide 1 (GLP1, encoded by gcg gene) in response to nutrient uptake. We aimed to investigate whether offspring from overweight rats develop anomalies in the barrier function and incretin transcription. We observed pro-inflammatory related changes along with a reduction in Claudin-3 levels resulting in increased gut-permeability in fetuses and offspring from overweight rats. Importantly, we found decreased gip mRNA levels in both fetuses and offspring from overweight rats. Differently, gcg mRNA levels were upregulated in fetuses, downregulated in female offspring and unchanged in male offspring from overweight rats. When cultured with high glucose, intestinal explants showed an increase in gip and gcg mRNA levels in control offspring. In contrast, offspring from overweight rats did not exhibit any response in gip mRNA levels. Additionally, while females showed no response, male offspring from overweight rats did exhibit an upregulation in gcg mRNA levels. Furthermore, female and male offspring from overweight rats showed sex-dependent anomalies when orally challenged with a glucose overload, returning to baseline glucose levels after 120 min. These results open new research questions about the role of the adverse maternal metabolic condition in the programming of impairments in glucose homeostasis, enteroendocrine function and gut barrier function in the offspring from overweight mothers and highlight the importance of a perinatal maternal healthy metabolism.