Publications by authors named "Tamer Coskun"

Aims: To explore the relationship between weight loss and insulin sensitivity in response to tirzepatide or semaglutide.

Materials And Methods: We conducted a post hoc exploratory analysis of a 28-week, double-blind, randomized trial in people with type 2 diabetes treated with metformin, randomized to tirzepatide 15 mg, semaglutide 1 mg or placebo. We evaluated the relationship between change in body weight and change in insulin sensitivity determined from hyperinsulinemic euglycemic clamp (M value), or from mixed-meal tolerance testing (Matsuda index).

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Growth differentiation factor 15, GDF15, and glucagon-like peptide-1 (GLP-1) analogues act through brainstem neurons that co-localise their receptors, GDNF-family receptor α-like (GFRAL) and GLP1R, to reduce food intake and body weight. However, their use as clinical treatments is partially hampered since both can also induce sickness-like behaviours, including aversion, that are mediated through a well-characterised pathway via the exterolateral parabrachial nucleus. Here, in mice, we describe a separate pathway downstream of GFRAL/GLP1R neurons that involves a distinct population of brain-derived neurotrophic factor (BDNF) cells in the medial nucleus of the tractus solitarius.

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Orally bioavailable, synthetic nonpeptide agonists (NPAs) of the glucagon-like peptide-1 receptor (GLP-1R) may offer an effective, scalable pharmacotherapy to address the metabolic disease epidemic. One of the first molecules in the emerging class of GLP-1R NPAs is orforglipron, which is in clinical development for treating type 2 diabetes and obesity. Here, we characterized the pharmacological properties of orforglipron in comparison with peptide-based GLP-1R agonists and other NPAs.

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Article Synopsis
  • * Researchers developed a new glucagon receptor agonist, LY3324954, that has better potency and effectiveness compared to regular glucagon, and it showed a prolonged impact in various animal models.
  • * In tests, LY3324954 led to increased energy expenditure, weight loss, and better fat management in diet-induced obese mice, indicating its potential as a therapeutic option for obesity-related conditions.
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Tirzepatide, a glucose-dependent insulinotropic polypeptide/glucagon-like peptide 1 receptor (GIPR/GLP-1R) agonist, has, in clinical trials, demonstrated greater reductions in glucose, body weight, and triglyceride levels compared with selective GLP-1R agonists in people with type 2 diabetes (T2D). However, cellular mechanisms by which GIPR agonism may contribute to these improved efficacy outcomes have not been fully defined. Using human adipocyte and mouse models, we investigated how long-acting GIPR agonists regulate fasted and fed adipocyte functions.

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Background: Fatty acid uptake can be measured using PET and 14-(R,S)-[F]fluoro-6-thia-heptadecanoic acid ([F]FTHA). However, the relatively rapid rate of [F]FTHA metabolism significantly affects kinetic modeling of tissue uptake. Thus, there is a need for accurate chromatographic methods to analyze the unmetabolized [F]FTHA (parent fraction).

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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.

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Introduction: Tibial plateau fractures account for average 1% of all fractures in adults. They mostly related to high-energy trauma in young adult and milder traumatic injuries in elderly due to osteoporosis.

Case Report: In this case, we reported a 28-year-old male patient who admitted to the emergency room with painful and swollen bilateral knees who had fallen on his knees while playing leapfrog.

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Recent studies have found that glucose-dependent insulinotropic polypeptide receptor (GIPR) agonism can enhance the metabolic efficacy of glucagon-like peptide-1 receptor agonist treatment by promoting both weight-dependent and -independent improvements on systemic insulin sensitivity. These findings have prompted new investigations aimed at better understanding the broad metabolic benefit of GIPR activation. Herein, we determined whether GIPR agonism favorably influenced the pharmacologic efficacy of the insulin-sensitizing thiazolidinedione (TZD) rosiglitazone in obese insulin-resistant (IR) mice.

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Background: According to current consensus guidelines for type 2 diabetes management, bodyweight management is as important as attaining glycaemic targets. Retatrutide, a single peptide with agonist activity at the glucose-dependent insulinotropic polypeptide (GIP), GLP-1, and glucagon receptors, showed clinically meaningful glucose-lowering and bodyweight-lowering efficacy in a phase 1 study. We aimed to examine the efficacy and safety of retatrutide in people with type 2 diabetes across a range of doses.

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Background: Combined glucose-dependent insulinotropic polypeptide receptor (GIPR) and glucagon-like peptide-1 receptor (GLP1R) agonism is superior to single GLP1R agonism with respect to glycemic control and weight loss in obese patients with or without type 2 diabetes. As insulin resistance and obesity are strong risk factors for nonalcoholic fatty liver disease (NAFLD), in the current study we investigated the effects of combined GIPR/GLP1R agonism on NAFLD development.

Methods: Male APOE∗3-Leiden.

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Background: Retatrutide (LY3437943) is an agonist of the glucose-dependent insulinotropic polypeptide, glucagon-like peptide 1, and glucagon receptors. Its dose-response relationships with respect to side effects, safety, and efficacy for the treatment of obesity are not known.

Methods: We conducted a phase 2, double-blind, randomized, placebo-controlled trial involving adults who had a body-mass index (BMI, the weight in kilograms divided by the square of the height in meters) of 30 or higher or who had a BMI of 27 to less than 30 plus at least one weight-related condition.

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Aim: To evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of single and multiple doses of orforglipron (LY3502970), an oral, non-peptide glucagon-like peptide-1 receptor agonist (GLP-1RA) in healthy participants.

Materials And Methods: This was a double-blind, placebo-controlled, Phase 1 study. Overtly healthy adults aged 18 to 65 years with body mass index of 20 to 40 kg/m and glycated haemoglobin concentration of 47.

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Aim: To report the results of a Phase 1b trial evaluating the safety, pharmacokinetics and pharmacodynamics of orforglipron (LY3502970), an oral, non-peptide glucagon-like peptide-1 receptor agonist (GLP-1RA), in patients with type 2 diabetes (T2D).

Materials And Methods: This was a double-blind, placebo-controlled Phase 1 study evaluating five different dosing regimens. The first group established that weekly dose escalation of the daily doses of orforglipron was generally well tolerated.

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Background And Aims: Combined agonism of the glucose-dependent insulinotropic polypeptide receptor (GIPR) and the glucagon-like peptide-1 receptor (GLP1R) is superior to single GLP1R agonism in terms of glycemic control and lowering body weight in individuals with obesity and with or without type 2 diabetes mellitus. As both GIPR and GLP1R signaling have also been implicated in improving inflammatory responses and lipid handling, two crucial players in atherosclerosis development, here we aimed to investigate the effects of combined GIPR/GLP1R agonism in APOE*3-Leiden.CETP mice, a well-established mouse model for human-like lipoprotein metabolism and atherosclerosis development.

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Objective: To evaluate the effects of tirzepatide on body composition, appetite, and energy intake to address the potential mechanisms involved in body weight loss with tirzepatide.

Research Design And Methods: In a secondary analysis of a randomized, double-blind, parallel-arm study, the effects of tirzepatide 15 mg (N = 45), semaglutide 1 mg (N = 44), and placebo (N = 28) on body weight and composition, appetite, and energy intake were assessed at baseline and week 28.

Results: Tirzepatide treatment demonstrated significant reductions in body weight compared with placebo and semaglutide, resulting in greater fat mass reduction.

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Aim: To clarify the effects of glucose-dependent insulinotropic polypeptide (GIP) receptor agonists (GIPRAs) on feeding and body weight.

Materials And Methods: Acute and subchronic effects of subcutaneous GIPFA-085, a long-acting GIPRA, on blood glucose, food intake, body weight, respiratory exchange ratio and plasma leptin levels were measured in diet-induced obese (DIO) mice and/or functional leptin-deficient ob/ob mice. The effects of GIPFA-085 on the hypothalamic arcuate nucleus (ARC) neurons from lean and DIO mice were studied by measuring cytosolic Ca concentration ([Ca ] ).

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Background And Purpose: Chronic heart failure, a progressive disease with limited treatment options currently available, especially in heart failure with preserved ejection fraction (HFpEF), represents an unmet medical need as well as an economic burden. The development of a novel therapeutic to slow or reverse disease progression would be highly impactful to patients and society. Relaxin-2 (relaxin) is a human hormone regulating cardiovascular, renal, and pulmonary adaptations during pregnancy.

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GDF15 and its receptor GFRAL/RET form a non-homeostatic system that regulates food intake and body weight in preclinical species. Here, we describe a GDF15 analog, LY3463251, a potent agonist at the GFRAL/RET receptor with prolonged pharmacokinetics. In rodents and obese non-human primates, LY3463251 decreased food intake and body weight with no signs of malaise or emesis.

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Background: Treating hyperglycaemia and obesity in individuals with type 2 diabetes using multi-receptor agonists can improve short-term and long-term outcomes. LY3437943 is a single peptide with agonist activity for glucagon, glucose-dependent insulinotropic polypeptide (GIP), and glucagon-like peptide 1 (GLP-1) receptors that is currently in development for the treatment of type 2 diabetes and for the treatment of obesity and associated comorbidities. We investigated the safety, pharmacokinetics, and pharmacodynamics of multiple weekly doses of LY3437943 in people with type 2 diabetes in a 12-week study.

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Aim: To investigate the role of glucose-dependent insulinotropic polypeptide receptor (GIPR) agonists alone or combined with glucagon-like peptide-1 receptor (GLP-1R) agonists to regulate palatable food intake and the role of specific macronutrients in these preferences.

Methods: To understand this regulation, we treated mice and rats on several choice diet paradigms of chow and a palatable food option with individual or dual GIPR and GLP-1R agonists.

Results: In mice, the dual agonist tirzepatide suppressed total caloric intake, while promoting the intake of chow over a high fat/sucrose diet.

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With an increasing prevalence of obesity, there is a need for new therapies to improve body weight management and metabolic health. Multireceptor agonists in development may provide approaches to fulfill this unmet medical need. LY3437943 is a novel triple agonist peptide at the glucagon receptor (GCGR), glucose-dependent insulinotropic polypeptide receptor (GIPR), and glucagon-like peptide-1 receptor (GLP-1R).

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