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Effects of exenatide on cardiac function, perfusion, and energetics in type 2 diabetic patients with cardiomyopathy: a randomized controlled trial against insulin glargine.

ABSTRACT: Multiple bloodglucose-lowering agents have been linked to cardiovascular events. Preliminary studies showed improvement in left ventricular (LV) function during glucagon-like peptide-1 receptor agonist administration. Underlying mechanisms, however, are unclear. The purpose of this study was to investigate myocardial perfusion and oxidative metabolism in type 2 diabetic (T2DM) patients with LV systolic dysfunction as compared to healthy controls. Furthermore, effects of 26-weeks of exenatide versus insulin glargine administration on cardiac function, perfusion and oxidative metabolism in T2DM patients with LV dysfunction were explored.Twenty-six T2DM patients with LV systolic dysfunction (cardiac magnetic resonance (CMR) derived LV ejection fraction (LVEF) of 47 ± 13%) and 10 controls (LVEF of 59 ± 4%, P < 0.01 as compared to patients) were analyzed. Both myocardial perfusion during adenosine-induced hyperemia (P < 0.01), and coronary flow reserve (P < 0.01), measured by [15O]H2O positron emission tomography (PET), were impaired in T2DM patients as compared to healthy controls. Myocardial oxygen consumption and myocardial efficiency, measured using [11C]acetate PET and CMR derived stroke volume, were not different between the groups. Eleven patients in the exenatide group and 12 patients in the insulin glargine group completed the trial. Systemic metabolic control was improved after both treatments, although, no changes in cardiac function, perfusion and metabolism were seen after exenatide or insulin glargine.T2DM patients with LV systolic dysfunction did not have altered myocardial efficiency as compared to healthy controls. Exenatide or insulin glargine had no effects on cardiac function, perfusion or oxidative metabolism. Trial registration NCT00766857.

SUBMITTER: Chen WJY

PROVIDER: S-EPMC5438489 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature

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Effects of exenatide on cardiac function, perfusion, and energetics in type 2 diabetic patients with cardiomyopathy: a randomized controlled trial against insulin glargine.

Chen Weena J Y WJY Diamant Michaela M de Boer Karin K Harms Hendrik J HJ Robbers Lourens F H J LFHJ van Rossum Albert C AC Kramer Mark H H MHH Lammertsma Adriaan A AA Knaapen Paul P

Cardiovascular diabetology 20170519 1

<h4>Background</h4>Multiple bloodglucose-lowering agents have been linked to cardiovascular events. Preliminary studies showed improvement in left ventricular (LV) function during glucagon-like peptide-1 receptor agonist administration. Underlying mechanisms, however, are unclear. The purpose of this study was to investigate myocardial perfusion and oxidative metabolism in type 2 diabetic (T2DM) patients with LV systolic dysfunction as compared to healthy controls. Furthermore, effects of 26-wee ...[more]

PMID: 28526033

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Project description:Hypertrophic cardiomyopathy (HCM) is a complex disease partly explained by the effects of individual gene variants on sarcomeric protein biomechanics. At the cellular level, HCM mutations most commonly enhance force production, leading to higher energy demands. Despite significant advances in elucidating sarcomeric structure-function relationships, there is still much to be learned about the mechanisms that link altered cardiac energetics to HCM phenotypes. In this work, we test the hypothesis that changes in cardiac energetics represent a common pathophysiologic pathway in HCM. We performed a comprehensive multi-omics profile of the molecular (transcripts, metabolites, and complex lipids), ultrastructural, and functional components of HCM energetics using myocardial samples from 27 HCM patients and 13 normal controls (donor hearts). Integrated omics analysis revealed alterations in a wide array of biochemical pathways with major dysregulation in fatty acid metabolism, reduction of acylcarnitines, and accumulation of free fatty acids. HCM hearts showed evidence of global energetic decompensation manifested by a decrease in high energy phosphate metabolites (ATP, ADP, and phosphocreatine) and a reduction in mitochondrial genes involved in the creatine kinase and ATP synthesis. Accompanying these metabolic derangements, quantitative electron microscopy showed an increased fraction of severely damaged mitochondria with reduced cristae density, coinciding with reduced citrate synthase (CS) activity and mitochondrial oxidative respiration. These mitochondrial abnormalities were associated with elevated reactive oxygen species (ROS) and reduced antioxidant defenses. However, despite significant mitochondrial injury, HCM hearts failed to upregulate mitophagic clearance. Overall, our findings suggest that perturbed metabolic signaling and mitochondrial dysfunction are common pathogenic mechanisms in patients with HCM. These results highlight potential new drug targets for attenuation of the clinical disease through improving metabolic function and reducing mitochondrial injury.

Project description:BackgroundHypertrophic cardiomyopathy (HCM) is a complex disease partly explained by the effects of individual gene variants on sarcomeric protein biomechanics. At the cellular level, HCM mutations most commonly enhance force production, leading to higher energy demands. Despite significant advances in elucidating sarcomeric structure-function relationships, there is still much to be learned about the mechanisms that link altered cardiac energetics to HCM phenotypes. In this work, we test the hypothesis that changes in cardiac energetics represent a common pathophysiologic pathway in HCM.MethodsWe performed a comprehensive multiomics profile of the molecular (transcripts, metabolites, and complex lipids), ultrastructural, and functional components of HCM energetics using myocardial samples from 27 HCM patients and 13 normal controls (donor hearts).ResultsIntegrated omics analysis revealed alterations in a wide array of biochemical pathways with major dysregulation in fatty acid metabolism, reduction of acylcarnitines, and accumulation of free fatty acids. HCM hearts showed evidence of global energetic decompensation manifested by a decrease in high energy phosphate metabolites (ATP, ADP, and phosphocreatine) and a reduction in mitochondrial genes involved in creatine kinase and ATP synthesis. Accompanying these metabolic derangements, electron microscopy showed an increased fraction of severely damaged mitochondria with reduced cristae density, coinciding with reduced citrate synthase activity and mitochondrial oxidative respiration. These mitochondrial abnormalities were associated with elevated reactive oxygen species and reduced antioxidant defenses. However, despite significant mitochondrial injury, HCM hearts failed to upregulate mitophagic clearance.ConclusionsOverall, our findings suggest that perturbed metabolic signaling and mitochondrial dysfunction are common pathogenic mechanisms in patients with HCM. These results highlight potential new drug targets for attenuation of the clinical disease through improving metabolic function and reducing mitochondrial injury.

Project description:INTRODUCTION:Increasing the frequency of blood glucose monitoring aids the evaluation of glycemic variability and blood glucose control by antidiabetic drugs. It remains unclear, however, whether GLP-1 receptor agonists or basal insulin has a better effect on glycemic variability in type 2 diabetes mellitus (T2DM) patients who are inadequately controlled by metformin. We used a continuous glucose monitoring system (CGMS) to compare patients on a GLP-1 receptor agonist with patients on basal insulin in terms of glycemic variability. METHODS:This prospective randomized study assigned T2DM patients treated with metformin (N = 39) to either exenatide treatment or insulin glargine treatment for 16 weeks. Glycemic variability was assessed using a CGMS; hemoglobin A1c (HbA1c), β-cell function, weight, body mass index (BMI), and waist circumference were also evaluated. RESULTS:Mean blood glucose level, continuous overlapping net glycemic action, mean amplitude of glycemic excursions, percentage of the time that the blood glucose value was > 10.0 mmol/L, and highest blood glucose level (P < 0.01-0.05) significantly decreased in both groups. Standard deviation of the mean glucose value, largest amplitude of glycemic excursions, and waist circumference significantly decreased for those treated with exenatide (P < 0.05), while no changes were observed with insulin glargine treatment. Percentage of the time that the blood glucose value was > 7.8 mmol/L decreased after insulin glargine use (P < 0.05) but not with the exenatide intervention. Similar decreases in fasting blood glucose and HbA1c and increases in the 1/homeostasis model assessment of insulin resistance, disposition index 30, and disposition index 120 were observed in both groups (P < 0.01-0.05). Reductions in weight and BMI were greater with exenatide than with insulin glargine treatment (P < 0.05). CONCLUSIONS:In overweight and obese patients with T2DM inadequately controlled by metformin, exenatide and insulin glargine have similar efficacies in terms of glycemic variability, HbA1c alleviation, and β-cell function, but exenatide has a greater effect on body weight and BMI.

Project description:RationaleDiabetic patients develop cardiomyopathy characterized by hypertrophy, diastolic dysfunction, and intracellular lipid accumulation, termed lipotoxicity. Diabetic hearts utilize fatty acids as a major energy source, which produces high levels of oxidative stress, thereby inducing mitochondrial dysfunction.ObjectiveTo elucidate how mitochondrial function is regulated in diabetic cardiomyopathy.Methods and resultsMice were fed either a normal diet or high-fat diet (HFD, 60 kcal % fat). Although autophagic flux was activated by HFD consumption, peaking at 6 weeks ( P<0.05), it was attenuated thereafter. Mitophagy, evaluated with Mito-Keima, was increased after 3 weeks of HFD feeding (mitophagy area: 8.3% per cell with normal diet and 12.4% with HFD) and continued to increase even after 2 months ( P<0.05). By isolating adult cardiomyocytes from GFP-LC3 mice fed HFD, we confirmed that mitochondria were sequestrated by LC3-positive autophagosomes during mitophagy. In wild-type mice, cardiac hypertrophy, diastolic dysfunction (end diastolic pressure-volume relationship =0.051±0.009 in normal diet and 0.11±0.004 in HFD) and lipid accumulation occurred within 2 months of HFD feeding ( P<0.05). Deletion of atg7 impaired mitophagy, increased lipid accumulation, exacerbated diastolic dysfunction (end diastolic pressure-volume relationship =0.11±0.004 in wild type and 0.152±0.019 in atg7 cKO; P<0.05) and induced systolic dysfunction (end systolic pressure-volume relationship =24.86±2.46 in wild type and 15.93±1.76 in atg7 cKO; P<0.05) during HFD feeding. Deletion of Parkin partially inhibited mitophagy, increased lipid accumulation and exacerbated diastolic dysfunction (end diastolic pressure-volume relationship =0.124±0.005 in wild type and 0.176±0.018 in Parkin KO, P<0.05) in response to HFD feeding. Injection of TB1 (Tat-Beclin1) activated mitophagy, attenuated mitochondrial dysfunction, decreased lipid accumulation, and protected against cardiac diastolic dysfunction (end diastolic pressure-volume relationship =0.110±0.009 in Control peptide and 0.078±0.015 in TB1, P<0.05) during HFD feeding.ConclusionsMitophagy serves as an essential quality control mechanism for mitochondria in the heart during HFD consumption. Impairment of mitophagy induces mitochondrial dysfunction and lipid accumulation, thereby exacerbating diabetic cardiomyopathy. Conversely, activation of mitophagy protects against HFD-induced diabetic cardiomyopathy.

Project description:Background Diabetic cardiomyopathy (DCM) remains asymptomatic for many years until progression to asymptomatic left ventricular diastolic dysfunction (ALVDD), a subclinical cardiac abnormality present in early-stage DCM. Because LV function in patients with type 2 diabetes mellitus (T2DM) may be subtly altered long before the onset of ALVDD, quantitative assessment of the risk of progression to early-stage DCM in T2DM patients with normal hearts is critical for delaying or even reversing DCM. Objective This study aimed to establish a nomogram with the aid of DCM characteristics revealed by multimodal echocardiography to assess the likelihood of the progression to early-stage DCM in T2DM patients with normal cardiac function. Methods Of the 423 T2DM patients enrolled, 302 were included in the training cohort and 121 in the validation cohort. The clinical characteristics, biochemical data, and multimodal echocardiographic parameters were collected. In the training cohort, the screened correlates of ALVDD were utilized to develop a nomogram for estimating the risk coefficient for early-stage DCM. This model was validated both in the training and validation cohorts. Results ALVDD was independently correlated with the number of comorbidities [with one comorbidity: odds ratio (OR) = 3.009; with two comorbidities: OR = 4.026], HbA1c (OR = 1.773), myocardial blood flow (OR = 0.841), and global longitudinal strain (OR = 0.856) (all P < 0.05). They constituted a nomogram to visualize the likelihood of DCM development in T2DM patients with normal cardiac function. The model was validated to present strong discrimination and calibration, and obtained clinical net benefits both in the training and validation cohorts. Conclusion We constructed and validated a nomogram to estimate the likelihood of developing early-stage DCM in T2DM patients with normal cardiac function. The alteration of the nomogram-predicted risk coefficient is expected to be proposed as a therapeutic target to slow or stop DCM progression.

Dataset Information

Effects of exenatide on cardiac function, perfusion, and energetics in type 2 diabetic patients with cardiomyopathy: a randomized controlled trial against insulin glargine.

Publications

Effects of exenatide on cardiac function, perfusion, and energetics in type 2 diabetic patients with cardiomyopathy: a randomized controlled trial against insulin glargine.

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