incretins and Hypertrophy--Left-Ventricular

Heart failure is one of the major cardiovascular complications in patients with type 2 diabetes mellitus (T2DM) and increases the risk of morbidity and mortality. Although active management for heart failure is needed in patients with T2DM, traditional treatment and some new class of antihyperglycemic drugs, such as glucagon-like peptide-1 receptor agonists or dipeptidyl peptidase-4 inhibitors, could not reduce the risk of heart failure. Recent major trials demonstrated sodium-glucose co-transporter-2 (SGLT2) inhibitors improve prognosis of T2DM patients through prevention of heart failure. Both heart failure with reduced ejection fraction and that with preserved ejection fraction (HFpEF) is observed in T2DM patients, and HFpEF is often overlooked and misdiagnosed in these population. Left ventricular hypertrophy, left atrial dilatation, diastolic dysfunction, and subclinical systolic dysfunction indicated as reduced global longitudinal strain are major abnormalities on echocardiography in patients with diabetic cardiomyopathy. These structural and functional changes are also prevalent in the general patients with T2DM, and those with these abnormalities have higher incidence of heart failure than those without them. Glycemic control might improve some of these abnormalities on echocardiography, but it is still unclear whether their improvement could be associated with risk reduction for heart failure. At now, there are only limited data on the effects of DPP-4 inhibitors or SGLT2 inhibitors on echocardiography in T2DM patients. Large-scale trials are needed to clarify how antihyperglycemic drugs affect echocardiographic parameters.

Topics: Diabetes Mellitus, Type 2; Diabetic Cardiomyopathies; Dipeptidyl-Peptidase IV Inhibitors; Echocardiography; Heart Failure; Humans; Hypertrophy, Left Ventricular; Hypoglycemic Agents; Incretins; Sodium-Glucose Transporter 2 Inhibitors; Stroke Volume

Heart failure with preserved ejection fraction (HFpEF) is a multifactorial disease that constitutes several distinct phenotypes, including a common cardiometabolic phenotype with obesity and type 2 diabetes mellitus. Treatment options for HFpEF are limited, and development of novel therapeutics is hindered by the paucity of suitable preclinical HFpEF models that recapitulate the complexity of human HFpEF. Metabolic drugs, like glucagon-like peptide receptor agonist (GLP-1 RA) and sodium-glucose co-transporter 2 inhibitors (SGLT2i), have emerged as promising drugs to restore metabolic perturbations and may have value in the treatment of the cardiometabolic HFpEF phenotype. We aimed to develop a multifactorial HFpEF mouse model that closely resembles the cardiometabolic HFpEF phenotype, and evaluated the GLP-1 RA liraglutide (Lira) and the SGLT2i dapagliflozin (Dapa).. Aged (18-22 months old) female C57BL/6J mice were fed a standardized chow (CTRL) or high-fat diet (HFD) for 12 weeks. After 8 weeks HFD, angiotensin II (ANGII), was administered for 4 weeks via osmotic mini pumps. HFD + ANGII resulted in a cardiometabolic HFpEF phenotype, including obesity, impaired glucose handling, and metabolic dysregulation with inflammation. The multiple hit resulted in typical clinical HFpEF features, including cardiac hypertrophy and fibrosis with preserved fractional shortening but with impaired myocardial deformation, atrial enlargement, lung congestion, and elevated blood pressures. Treatment with Lira attenuated the cardiometabolic dysregulation and improved cardiac function, with reduced cardiac hypertrophy, less myocardial fibrosis, and attenuation of atrial weight, natriuretic peptide levels, and lung congestion. Dapa treatment improved glucose handling, but had mild effects on the HFpEF phenotype.. We developed a mouse model that recapitulates the human HFpEF disease, providing a novel opportunity to study disease pathogenesis and the development of enhanced therapeutic approaches. We furthermore show that attenuation of cardiometabolic dysregulation may represent a novel therapeutic target for the treatment of HFpEF.

Topics: Angiotensin II; Animals; Benzhydryl Compounds; Blood Glucose; Diet, High-Fat; Disease Models, Animal; Female; Fibrosis; Gene Expression Regulation; Glucagon-Like Peptide-1 Receptor; Glucosides; Heart Failure, Diastolic; Hypertrophy, Left Ventricular; Incretins; Liraglutide; Mice, Inbred C57BL; Myocardium; Signal Transduction; Sodium-Glucose Transporter 2 Inhibitors; Ventricular Function, Left; Ventricular Remodeling

Mammalian target of rapamycin (mTOR) and a ribosomal protein S6 kinase (p70S6K) mediate tissue fibrosis and negatively regulate autophagy. This study aims to investigate whether glucagon-like peptide-1 (GLP-1) analog liraglutide protects the heart against aortic banding-induced cardiac fibrosis and dysfunction through inhibiting mTOR/p70S6K signaling and promoting autophagy activity. Male SD rats were randomly divided into four groups (n = 6/each group): sham operated control; abdominal aortic constriction (AAC); liraglutide treatment during AAC (0.3 mg/kg, injected subcutaneously twice daily); rapamycin treatment during AAC (0.2 mg/kg/day, administered by gastric gavage). Relative to the animals with AAC on week 16, liraglutide treatment significantly reduced heart/body weight ratio, inhibited cardiomyocyte hypertrophy, and augmented plasma GLP-1 level and tissue GLP-1 receptor expression. Phosphorylation of mTOR/p70S6K, populations of myofibroblasts and synthesis of collagen I/III in the myocardium were simultaneously inhibited. Furthermore, autophagy regulating proteins: LC3-II/LC3-I ratio and Beclin-1 were upregulated, and p62 was downregulated by liraglutide. Compared with liraglutide group, treatment with rapamycin, a specific inhibitor of mTOR, compatibly augmented GLP-1 receptor level, inhibited phosphorylation of mTOR/p70S6K and expression of p62 as well as increased level of LC3-II/LC3-I ratio and Beclin-1, suggesting that there is an interaction between GLP-1 and mTOR/p70S6K signaling in the regulation of autophagy. In line with these modifications, treatment with liraglutide and rapamycin significantly reduced perivascular/interstitial fibrosis, and preserved systolic/diastolic function. These results suggest that the inhibitory effects of liraglutide on cardiac fibrosis and dysfunction are potentially mediated by inhibiting mTOR/p70S6K signaling and enhancing autophagy activity.

Topics: Animals; Aorta, Abdominal; Autophagy; Autophagy-Related Proteins; Disease Models, Animal; Fibrosis; Glucagon-Like Peptide 1; Glucagon-Like Peptide-1 Receptor; Hypertrophy, Left Ventricular; Incretins; Ligation; Male; Myocytes, Cardiac; Myofibroblasts; Phosphorylation; Protein Kinase Inhibitors; Rats, Sprague-Dawley; Ribosomal Protein S6 Kinases, 70-kDa; Signal Transduction; TOR Serine-Threonine Kinases; Ventricular Function, Left; Ventricular Remodeling

Despite its high prevalence among patients suffering myocardial infarction, the significance of left ventricle hypertrophy for infarct size is not known. We asked whether infarct size might be increased by this condition, and whether any such increase might be associated with an increased mitochondrial damage following coronary occlusion.. Occlusion of the left descending artery in isolated, perfused hearts of SHR-SP (spontaneously hypertensive rat stroke-prone) (left ventricular hypertrophy) or Wistar-Kyoto (WKY) (control) rats was used, followed by reperfusion with or without exendin-4 (Exe-4), a glucagon-like peptide-1 receptor agonist. Infarct size relative to area-at-risk was determined. Separately, mitochondria were isolated after global ischemia. Activities of complexes III and IV and amounts of selected complex subunits and cytochromes a, b, c, and c1 were determined.. Infarct size (ischemia 35  min and 120  min reperfusion) was 65.8% (±3.3%) and 37.1% (±3.4%) in the SHR-SP and WKY hearts, respectively (P < 0.05). Exe-4 significantly decreased infarct size and hypercontracture in WKY, but not in SHR-SP, hearts. After ischemia 15  min in SHR-SP hearts, Exe-4 reduced the infarct (26.6%, ±3.8% to 9.3% ± 1.5%; P < 0.05). Mitochondria from postischemic SHR-SP hearts showed a reduction of complex III (368.1 ± 37.5 to 175.8 ± 23.0  nmoles/min × mg; P < 0.05) and complex IV (14.4 ± 0.22 to 5.8 ± 0.8 1/s × mg; P < 0.05) activities and decreased amounts of cytochromes a, b, and c.. Hearts from hypertensive (SHR-SP) rats with left ventricle hypertrophy appeared more vulnerable to ischemia-reperfusion injury, as supported by a more profound infarct development and an earlier loss of postconditioning by Exe-4. Mitochondrial complexes III and IV were identified among possible loci of this increased, hypertrophy-associated vulnerability.

Topics: Animals; Cytochromes; Electron Transport Complex III; Electron Transport Complex IV; Exenatide; Heart; Hypertension; Hypertrophy, Left Ventricular; Incretins; Male; Myocardial Infarction; Myocardial Reperfusion Injury; Myocardium; Peptides; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Severity of Illness Index; Venoms

Studies have indicated that dipeptidyl peptidase-4 (DPP-4) inhibitors and glucagon-like peptide-1 (GLP-1) agonists reduce infarct size after myocardial ischaemia. Whether these agents modify cardiac remodelling after ischaemia is unclear. Furthermore, it is not known if combination of the two types of drugs is superior to either agent alone. We investigated the modulatory effect of the DPP-4 inhibitor linagliptin alone, the GLP-1 activator liraglutide alone, or the two agents together on myocardial infarct size, left ventricular contractile function and cardiac remodelling signals after a brief period of left coronary artery (LCA) occlusion. C57BL/6 mice were treated with vehicle, the DPP-4 inhibitor linagliptin, the GLP-1 activator liraglutide, or both agents together for 5 days, and then subjected to LCA occlusion (1 h) and reperfusion (3 h). Ischaemia-reperfusion increased reactive oxygen species (ROS) generation and expression of NADPH oxidase (p47(phox), p22(phox) and gp91(phox) subtypes), collagens, fibronectin and proinflammatory cytokines (interleukin 6, tumour necrosis factor α and monocyte chemoattractant protein-1) in the LCA-supplied regions. Pre-treatment with linagliptin or liraglutide reduced infarct size, protected cardiomyocytes from injury and preserved cardiac contractile function in a similar fashion. It is interesting that profibrotic (collagen deposition) signals were expressed soon after ischaemia-reperfusion. Both linagliptin and liraglutide suppressed ROS generation, NADPH oxidase and proinflammatory signals, and reduced collagen deposition. Addition of linagliptin or liraglutide had no significant additive effect above and beyond that of liraglutide and linagliptin given alone. In conclusion, linagliptin and liraglutide can improve cardiac contractile function and indices of cardiac remodelling, which may be related to their role in inhibition of ROS production and proinflammatory cytokines after ischaemia.

Topics: Animals; Anti-Inflammatory Agents; Antioxidants; Cardiotonic Agents; Collagen; Cytokines; Cytoprotection; Dipeptidyl-Peptidase IV Inhibitors; Disease Models, Animal; Drug Therapy, Combination; Hypertrophy, Left Ventricular; Incretins; Inflammation Mediators; Linagliptin; Liraglutide; Male; Mice, Inbred C57BL; Myocardial Contraction; Myocardial Infarction; Myocardial Reperfusion Injury; Myocardium; NADPH Oxidases; Oxidative Stress; Reactive Oxygen Species; Ventricular Function, Left; Ventricular Remodeling