Incretin hormones potentiate the glucose-induced insulin secretion following enteral nutrient intake. The best characterised incretin hormones are glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) which are produced in and secreted from the gut in response to nutrient ingestion. The property of incretins to enhance endogenous insulin secretion only at elevated blood glucose levels makes them interesting therapeutics for type 2 diabetes mellitus with a better safety profile than exogenous insulin. While incretin therapeutics (especially GLP-1 agonists, and more recently also GLP-1 / GIP dual agonists and other drugs that influence the incretin metabolism (e.g., dipeptidyl peptidase-4 (DPP-4) inhibitors)) are already widely used treatment options for human type 2 diabetes, these drugs are not yet approved for the therapy of feline diabetes mellitus. This review provides an introduction to incretins and feline diabetes mellitus in general and summarises the current study situation on incretins as therapeutics for feline diabetes mellitus to assess their possible future potential in feline medicine. Studies to date on the use of GLP-1 receptor agonists (GLP-1RA) in healthy cats largely confirm their insulinotropic effect known from other species. In diabetic cats, GLP-1RAs appear to significantly reduce glycaemic variability (GV, an indicator for the quality of glycaemic control), which is important for the management of the disease and prevention of long-term complications. However, for widespread use in feline diabetes mellitus, further studies are required that include larger numbers of diabetic cats, and that consider and test a possible need for dose adjustments to overweight and diabetic cats. Also evaluation of the outcome of GLP-1RA monotherapy will be neceessary.

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.

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

Metabolic illnesses, including obesity and type 2 diabetes, have become worldwide epidemics that have an effect on public health. Clinical investigations and further exploration of these mechanisms could lead to innovative, effective, and personalized treatment strategies for individuals. It is important to screen biomarkers in previous studies to discover what is missing. Glucagon-like peptide-1\'s role in insulin secretion and glucose control highlights its diagnostic and therapeutic potential. Glucose-dependent insulinotropic peptide\'s influence on postprandial satiety and weight management signifies its importance in understanding metabolic processes. Monocyte chemoattractant protein-1\'s involvement in inflammation and insulin resistance underlines its value as a diagnostic marker. Insulin-like growth factor-binding protein-7\'s association with insulin sensitivity and kidney function presents it as a potential target for these diseases\' management. In validating these biomarkers, it will be easier to reflect pathophysiological processes, and clinicians will be able to better assess disease severity, monitor disease progression, and tailor treatment strategies. The purpose of the study was to elucidate the significance of identifying novel biomarkers for type 2 diabetes mellitus and obesity, which can revolutionize early detection, risk assessment, and personalized treatment strategies. Standard literature searches of PubMed (MEDLINE), EMBASE, and Cochrane Library were conducted in the year 2023 to identify both original RCTs and recent systematic reviews that have explored the importance of identifying novel biomarkers for T2D and obesity. This search produced 1964 results, and then was reduced to randomized controlled trial and systematic reviews, producing 145 results and 44 results, respectively. Researchers have discovered potential associations between type 2 diabetes mellitus and obesity and the biomarkers glucagon-like peptide-1, glucose-dependent insulinotropic peptide, monocyte chemoattractant protein-1, and insulin-like growth factor-binding protein-7. Understanding the role of those biomarkers in disease pathogenesis offers hope for improving diagnostics, personalized treatment, and prevention strategies.

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

Serving whey protein before a meal in order to lower postprandial blood glucose concentrations is known as a premeal. The underlying mechanisms are only partly understood but may involve stimulation of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and insulin secretion together with a slower gastric emptying rate.
The objective of this systematic review and meta-analysis was to review all randomized clinical trials investigating premeals with whey protein in comparison with a nonactive comparator (control) that evaluated plasma glucose, GLP-1, GIP, insulin, and/or gastric emptying rate. Secondary aims included subgroup analyses on the timing and dose of the premeal together with the metabolic state of the participants [lean, obese, and type 2 diabetes mellitus (T2DM)].
We searched EMBASE, CENTRAL, PUBMED, and clinicaltrials.gov and found 16 randomized crossover trials with a total of 244 individuals. The last search was performed on 9 August, 2022.
Whey protein premeals lowered peak glucose concentration by -1.4 mmol/L [-1.9 mmol/L; -0.9 mmol/L], and the area under the curve for glucose was -0.9 standard deviation (SD) [-1.2 SD; -0.6 SD] compared with controls (high certainty). In association with these findings, whey protein premeals elevated GLP-1 (low certainty) and peak insulin (high certainty) concentrations and slowed gastric emptying rate (high certainty) compared with controls. Subgroup analyses showed a more pronounced and prolonged glucose-lowering effect in individuals with T2DM compared with participants without T2DM. The available evidence did not elucidate the role of GIP. The protein dose used varied between 4 and 55 g, and meta-regression analysis showed that the protein dose correlated with the glucose-lowering effects.
In conclusion, whey protein premeals lower postprandial blood glucose, reduce gastric emptying rate, and increase peak insulin. In addition, whey protein premeals may elevate plasma concentrations of GLP-1. Whey protein premeals may possess clinical potential, but the long-term effects await future clinical trials.

Diabetes Mellitus (DM) is a long-term metabolic condition that is characterized by excessive blood glucose. DM is the third most death-causing disease, leading to retinopathy, nephropathy, loss of vision, stroke, and cardiac arrest. Around 90% of the total cases of diabetic patients have Type II Diabetes Mellitus (T2DM). Among various approaches for the treatment of T2DM. G proteincoupled receptors (GPCRs) 119 have been identified as a new pharmacological target. GPR119 is distributed preferentially in the pancreas β-cells and gastrointestinal tract (enteroendocrine cells) in humans. GPR119 receptor activation elevates the release of incretin hormones such as Glucagon-Like Peptide (GLP1) and Glucose Dependent Insulinotropic Polypeptide (GIP) from intestinal K and L cells. GPR119 receptor agonists stimulate intracellular cAMP production via Gαs coupling to adenylate cyclase. GPR119 has been linked to the control of insulin release by pancreatic β-cells, as well as the generation of GLP-1 by enteroendocrine cells in the gut, as per in vitro assays. The dual role of the GPR119 receptor agonist in the treatment of T2DM leads to the development of a novel prospective anti-diabetic drug and is thought to have decreased the probability of inducing hypoglycemia. GPR119 receptor agonists exert their effects in one of two ways: either by promoting glucose absorption by β-cells, or by inhibiting α-cells\' ability to produce glucose. In this review, we summarized potential targets for the treatment of T2DM with special reference to GPR119 along with its pharmacological effects, several endogenous as well as exogenous agonists, and its pyrimidine nucleus containing synthetic ligands.

Background: There has been an emerging concern that non-nutritive sweeteners (NNS) can increase the risk of cardiometabolic disease. Much of the attention has focused on acute metabolic and endocrine responses to NNS. To examine whether these mechanisms are operational under real-world scenarios, we conducted a systematic review and network meta-analysis of acute trials comparing the effects of non-nutritive sweetened beverages (NNS beverages) with water and sugar-sweetened beverages (SSBs) in humans. Methods: MEDLINE, EMBASE, and The Cochrane Library were searched through to January 15, 2022. We included acute, single-exposure, randomized, and non-randomized, clinical trials in humans, regardless of health status. Three patterns of intake were examined: (1) uncoupling interventions, where NNS beverages were consumed alone without added energy or nutrients; (2) coupling interventions, where NNS beverages were consumed together with added energy and nutrients as carbohydrates; and (3) delayed coupling interventions, where NNS beverages were consumed as a preload prior to added energy and nutrients as carbohydrates. The primary outcome was a 2 h incremental area under the curve (iAUC) for blood glucose concentration. Secondary outcomes included 2 h iAUC for insulin, glucagon-like peptide 1 (GLP-1), gastric inhibitory polypeptide (GIP), peptide YY (PYY), ghrelin, leptin, and glucagon concentrations. Network meta-analysis and confidence in the network meta-analysis (CINeMA) were conducted in R-studio and CINeMA, respectively. Results: Thirty-six trials involving 472 predominantly healthy participants were included. Trials examined a variety of single NNS (acesulfame potassium, aspartame, cyclamate, saccharin, stevia, and sucralose) and NNS blends (acesulfame potassium + aspartame, acesulfame potassium + sucralose, acesulfame potassium + aspartame + cyclamate, and acesulfame potassium + aspartame + sucralose), along with matched water/unsweetened controls and SSBs sweetened with various caloric sugars (glucose, sucrose, and fructose). In uncoupling interventions, NNS beverages (single or blends) had no effect on postprandial glucose, insulin, GLP-1, GIP, PYY, ghrelin, and glucagon responses similar to water controls (generally, low to moderate confidence), whereas SSBs sweetened with caloric sugars (glucose and sucrose) increased postprandial glucose, insulin, GLP-1, and GIP responses with no differences in postprandial ghrelin and glucagon responses (generally, low to moderate confidence). In coupling and delayed coupling interventions, NNS beverages had no postprandial glucose and endocrine effects similar to controls (generally, low to moderate confidence). Conclusions: The available evidence suggests that NNS beverages sweetened with single or blends of NNS have no acute metabolic and endocrine effects, similar to water. These findings provide support for NNS beverages as an alternative replacement strategy for SSBs in the acute postprandial setting.

OBJECTIVE: This study aims to explore the efficacy and safety of tirzepatide for patients with type 2 diabetes (T2D).
METHODS: Using specific keywords, we comprehensively go through the potential articles on Europe PMC, Scopus, PubMed, and ClinicalTrials.gov sources until July 12th, 2022. We collected all clinical trials that compare tirzepatide 5, 10, or 15 mg once-weekly with placebo or other glucose lowering agents in adult patients with T2D.
RESULTS: Nine clinical trials were included. Our pooled analysis revealed the dose-dependent superiority of tirzepatide in reducing HbA1c, ranging from -1.50% with 5 mg to -1.80% with 15 mg when compared with placebo, -0.61% with 5 mg to -0.95% with 15 mg when compared with GLP-1 receptor agonist, and -0.70% with 5 mg to 1.09% with 15 mg when compared with basal insulin. The dose-dependent superiority of tirzepatide was also seen in the bodyweight reduction effect with all comparators. These superiorities were not accompanied by increased odds of hypoglycemia, but there is an increase in gastrointestinal adverse events incidence.
CONCLUSIONS: Tirzepatide has shown superiority in glycemic control and bodyweight reduction with a good safety profile in patients with T2D. Tirzepatide may become a future potential drug in the management of T2D.

A key factor for the insulin response to oral glucose is the pro-glucagon derived incretin hormone glucagon-like peptide-1 (GLP-1), together with the companion incretin hormone, glucose-dependent insulinotropic polypeptide (GIP). Studies in GIP and GLP-1 receptor knockout (KO) mice have been undertaken in several studies to examine this role of the incretin hormones. In the present study, we reviewed the literature on glucose and insulin responses to oral glucose in these mice. We found six publications with such studies reporting results of thirteen separate study arms. The results were not straightforward, since glucose intolerance in GIP or GLP-1 receptor KO mice were reported only in eight of the arms, whereas normal glucose tolerance was reported in five arms. A general potential weakness of the published study is that each of them have examined effects of only one single dose of glucose. In a previous study in mice with genetic deletion of both GLP-1 and GIP receptors we showed that these mice have impaired insulin response to oral glucose after large but not small glucose loads, suggesting that the relevance of the incretin hormones may be dependent on the glucose load. To further test this hypothesis, we have now performed a stepwise glucose administration through a gastric tube (from zero to 125mg) in model experiments in anesthetized female wildtype, GLP-1 receptor KO and GIP receptor KO mice. We show that GIP receptor KO mice exhibit glucose intolerance in the presence of impaired insulin response after 100 and 125 mg glucose, but not after lower doses of glucose. In contrast, GLP-1 receptor KO mice have normal glucose tolerance after all glucose loads, in the presence of a compensatory increase in the insulin response. Therefore, based on these results and the literature survey, we suggest that GIP and GLP-1 receptor KO mice retain normal glucose tolerance after oral glucose, except after large glucose loads in GIP receptor KO mice, and we also show an adaptive mechanism in GLP-1 receptor KO mice, which needs to be further examined.