Abstract 15649: Pharmacological Inhibition of Aldose Reductase by AT001 Prevents Abnormal Cardiac Energy Metabolism and Improves Heart Function in an Animal Model of Diabetic Cardiomyopathy

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Keshav Gopal ◽  
Qutuba Karwi ◽  
Seyed Amirhossein Tabatabaei Dakhili ◽  
Riccardo Perfetti ◽  
Ravichandran Ramasamy ◽  
...  

Introduction: Diabetic Cardiomyopathy (DCM) is a major cause of death in people with type 2 diabetes (T2D). Alterations in cardiac energy metabolism including increased fatty acid oxidation rates and reduced glucose oxidation rates are key contributing factors to the development of DCM. Studies have shown that Aldose Reductase (AR), an enzyme activated under hyperglycemic conditions, can modulate myocardial glucose and fatty acid oxidation, and promotes cardiac dysfunction. Hypothesis: Pharmacological inhibition of AR using a next-generation inhibitor AT-001, can mitigate DCM in mice by modulating cardiac energy metabolism and improving cardiac efficiency. Methods: Male human AR overexpressing (hAR-Tg) and C57BL/6J (Control) mice were subjected to experimental T2D (high-fat diet [60% kcal from lard] for 10-wk with a single intraperitoneal streptozotocin injection of 75 mg/kg) and treated for the last 3-wk with AT-001 (40mg/kg/day) or vehicle via oral gavage. Cardiac energy metabolism and in vivo cardiac function were assessed via isolated working heart perfusions and ultrasound echocardiography, respectively. Results: AT-001 treatment significantly improved cardiac energetics in a murine model of DCM (hAR-Tg mice with T2D). Particularly, AT-001-treated mice exhibited decreased cardiac fatty acid oxidation rates compared to the vehicle-treated mice (342 ± 53 vs 964 ± 130 nmol/min/g dry wt.). Concurrently, there was a significant decrease in cardiac oxygen consumption in the AT-001-treated compared to the vehicle-treated mice (41 ± 12 vs 60 ± 11 μmol/min/g dry wt.), suggesting increased cardiac efficiency. Furthermore, treatment with AT-001 prevented cardiac structural and functional abnormalities present in DCM, including diastolic dysfunction as reflected by an increase in the tissue Doppler E’/A’ ratio and decrease in E/E’ ratio. Moreover, AT-001 treatment prevented cardiac hypertrophy as reflected by a decrease in LV mass in AT-001-treated mice. Conclusions: AR inhibition with AT-001 prevents cardiac structural and functional abnormalities in a mouse model of DCM, and normalizes cardiac energetics by shifting cardiac metabolism towards a non-diabetic metabolic state.

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Tariq R Altamimi ◽  
Arata Fukushima ◽  
Liyan Zhang ◽  
Su Gao ◽  
Abhishek Gupta ◽  
...  

Impaired cardiac insulin signaling and high cardiac fatty acid oxidation rates are characteristics of diabetic cardiomyopathy. Potential roles for liver-derived metabolic factors in mediating cardiac energy homeostasis are underappreciated. Plasma levels of adropin, a liver secreted peptide, increase during feeding and decrease during fasting and diabetes. In skeletal muscle, adropin preferentially promotes glucose over fatty acid oxidation. We therefore determined what effect adropin has on cardiac energy metabolism, insulin signaling and cardiac efficiency. C57Bl/6 mice were fasted to accentuate the differences in adropin plasma levels between animals injected 3 times over 24 hr with either vehicle or adropin (450 nmol/kg i.p.). Despite fasting-induced predominance of fatty acid oxidation measured in isolated working hearts, insulin inhibition of fatty acid oxidation was re-established in adropin-treated mice (from 1022±143 to 517±56 nmol. g dry wt -1 . min -1 , p <0.05) compared to vehicle-treated mice (from 757±104 to 818±103 nmol. g dry wt -1 . min -1 ). Adropin-treated mice hearts showed higher cardiac work over the course of perfusion (p<0.05 vs. vehicle), which was accompanied by improved cardiac efficiency and enhanced phosphorylation of insulin signaling enzymes (tyrosine-IRS-1, AS160, p<0.05). Acute addition of adropin (2nM) to isolated working hearts from non-fasting mice showed a robust stimulation of glucose oxidation compared to vehicle-treated hearts (3025±401 vs 1708±292 nmol. g dry wt -1 . min -1 , p<0.05, respectively) with a corresponding inhibition of palmitate oxidation (325±61 vs 731±160 nmol. g dry wt -1 . min -1 , p<0.05, respectively), even in the presence of insulin. Acute adropin addition to hearts also increased IRS-1 tyrosine-phosphorylation as well as Akt, and GSK3β phosphorylation (p<0.05), suggesting acute receptor- and/or post-translational modification-mediated mechanisms. These results suggest adropin as a putative candidate for the treatment of diabetic cardiomyopathy.


2016 ◽  
Vol 311 (2) ◽  
pp. H347-H363 ◽  
Author(s):  
Arata Fukushima ◽  
Osama Abo Alrob ◽  
Liyan Zhang ◽  
Cory S. Wagg ◽  
Tariq Altamimi ◽  
...  

Dramatic maturational changes in cardiac energy metabolism occur in the newborn period, with a shift from glycolysis to fatty acid oxidation. Acetylation and succinylation of lysyl residues are novel posttranslational modifications involved in the control of cardiac energy metabolism. We investigated the impact of changes in protein acetylation/succinylation on the maturational changes in energy metabolism of 1-, 7-, and 21-day-old rabbit hearts. Cardiac fatty acid β-oxidation rates increased in 21-day vs. 1- and 7-day-old hearts, whereas glycolysis and glucose oxidation rates decreased in 21-day-old hearts. The fatty acid oxidation enzymes, long-chain acyl-CoA dehydrogenase (LCAD) and β-hydroxyacyl-CoA dehydrogenase (β-HAD), were hyperacetylated with maturation, positively correlated with their activities and fatty acid β-oxidation rates. This alteration was associated with increased expression of the mitochondrial acetyltransferase, general control of amino acid synthesis 5 like 1 (GCN5L1), since silencing GCN5L1 mRNA in H9c2 cells significantly reduced acetylation and activity of LCAD and β-HAD. An increase in mitochondrial ATP production rates with maturation was associated with the decreased acetylation of peroxisome proliferator-activated receptor-γ coactivator-1α, a transcriptional regulator for mitochondrial biogenesis. In addition, hypoxia-inducible factor-1α, hexokinase, and phosphoglycerate mutase expression declined postbirth, whereas acetylation of these glycolytic enzymes increased. Phosphorylation rather than acetylation of pyruvate dehydrogenase (PDH) increased in 21-day-old hearts, accounting for the low glucose oxidation postbirth. A maturational increase was also observed in succinylation of PDH and LCAD. Collectively, our data are the first suggesting that acetylation and succinylation of the key metabolic enzymes in newborn hearts play a crucial role in cardiac energy metabolism with maturation. Listen to this article’s corresponding podcast at http://ajpheart.podbean.com/e/acetylation-control-of-energy-metabolism-in-newborn-hearts/ .


Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 3259
Author(s):  
Qutuba G. Karwi ◽  
Qiuyu Sun ◽  
Gary D. Lopaschuk

Diabetes is a major risk factor for the development of cardiovascular disease via contributing and/or triggering significant cellular signaling and metabolic and structural alterations at the level of the heart and the whole body. The main cause of mortality and morbidity in diabetic patients is cardiovascular disease including diabetic cardiomyopathy. Therefore, understanding how diabetes increases the incidence of diabetic cardiomyopathy and how it mediates the major perturbations in cell signaling and energy metabolism should help in the development of therapeutics to prevent these perturbations. One of the significant metabolic alterations in diabetes is a marked increase in cardiac fatty acid oxidation rates and the domination of fatty acids as the major energy source in the heart. This increased reliance of the heart on fatty acids in the diabetic has a negative impact on cardiac function and structure through a number of mechanisms. It also has a detrimental effect on cardiac efficiency and worsens the energy status in diabetes, mainly through inhibiting cardiac glucose oxidation. Furthermore, accelerated cardiac fatty acid oxidation rates in diabetes also make the heart more vulnerable to ischemic injury. In this review, we discuss how cardiac energy metabolism is altered in diabetic cardiomyopathy and the impact of cardiac insulin resistance on the contribution of glucose and fatty acid to overall cardiac ATP production and cardiac efficiency. Furthermore, how diabetes influences the susceptibility of the myocardium to ischemia/reperfusion injury and the role of the changes in glucose and fatty acid oxidation in mediating these effects are also discussed.


Diabetes ◽  
2021 ◽  
Vol 70 (Supplement 1) ◽  
pp. 379-P
Author(s):  
KESHAV GOPAL ◽  
QUTUBA G. KARWI ◽  
SEYED AMIRHOSSEIN TABATABAEI DAKHILI ◽  
CORY S. WAGG ◽  
RICCARDO PERFETTI ◽  
...  

2014 ◽  
Vol 42 (4) ◽  
pp. 1043-1051 ◽  
Author(s):  
Osama Abo Alrob ◽  
Gary D. Lopaschuk

CoA (coenzyme A) and its derivatives have a critical role in regulating cardiac energy metabolism. This includes a key role as a substrate and product in the energy metabolic pathways, as well as serving as an allosteric regulator of cardiac energy metabolism. In addition, the CoA ester malonyl-CoA has an important role in regulating fatty acid oxidation, secondary to inhibiting CPT (carnitine palmitoyltransferase) 1, a key enzyme involved in mitochondrial fatty acid uptake. Alterations in malonyl-CoA synthesis by ACC (acetyl-CoA carboxylase) and degradation by MCD (malonyl-CoA decarboxylase) are important contributors to the high cardiac fatty acid oxidation rates seen in ischaemic heart disease, heart failure, obesity and diabetes. Additional control of fatty acid oxidation may also occur at the level of acetyl-CoA involvement in acetylation of mitochondrial fatty acid β-oxidative enzymes. We find that acetylation of the fatty acid β-oxidative enzymes, LCAD (long-chain acyl-CoA dehydrogenase) and β-HAD (β-hydroxyacyl-CoA dehydrogenase) is associated with an increase in activity and fatty acid oxidation in heart from obese mice with heart failure. This is associated with decreased SIRT3 (sirtuin 3) activity, an important mitochondrial deacetylase. In support of this, cardiac SIRT3 deletion increases acetylation of LCAD and β-HAD, and increases cardiac fatty acid oxidation. Acetylation of MCD is also associated with increased activity, decreases malonyl-CoA levels and an increase in fatty acid oxidation. Combined, these data suggest that malonyl-CoA and acetyl-CoA have an important role in mediating the alterations in fatty acid oxidation seen in heart failure.


2012 ◽  
Vol 302 (9) ◽  
pp. H1784-H1794 ◽  
Author(s):  
Tatsujiro Oka ◽  
Victoria H. Lam ◽  
Liyan Zhang ◽  
Wendy Keung ◽  
Virgilio J. J. Cadete ◽  
...  

During the neonatal period, cardiac energy metabolism progresses from a fetal glycolytic profile towards one more dependent on mitochondrial oxidative metabolism. In this study, we identified the effects of cardiac hypertrophy on neonatal cardiac metabolic maturation and its impact on neonatal postischemic functional recovery. Seven-day-old rabbits were subjected to either a sham or a surgical procedure to induce a left-to-right shunt via an aortocaval fistula to cause RV volume-overload. At 3 wk of age, hearts were isolated from both groups and perfused as isolated, biventricular preparations to assess cardiac energy metabolism. Volume-overload resulted in cardiac hypertrophy (16% increase in cardiac mass, P < 0.05) without evidence of cardiac dysfunction in vivo or in vitro. Fatty acid oxidation rates were 60% lower ( P < 0.05) in hypertrophied hearts than controls, whereas glycolysis increased 246% ( P < 0.05). In contrast, glucose and lactate oxidation rates were unchanged. Overall ATP production rates were significantly lower in hypertrophied hearts, resulting in increased AMP-to-ATP ratios in both aerobic hearts and ischemia-reperfused hearts. The lowered energy generation of hypertrophied hearts depressed functional recovery from ischemia. Decreased fatty acid oxidation rates were accompanied by increased malonyl-CoA levels due to decreased malonyl-CoA decarboxylase activity/expression. Increased glycolysis in hypertrophied hearts was accompanied by a significant increase in hypoxia-inducible factor-1α expression, a key transcriptional regulator of glycolysis. Cardiac hypertrophy in the neonatal heart results in a reemergence of the fetal metabolic profile, which compromises ATP production in the rapidly maturing heart and impairs recovery of function following ischemia.


Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Jian Cao ◽  
Stephen J Peterson ◽  
Gaia Favero ◽  
Rita Rezzani ◽  
Rodella Luigi Fabrizio ◽  
...  

Introduction: Myocardial Ischemia (MI), one of the major causes of heart failure, is associated with cardiac remodeling, insufficient angiogenesis and enhanced oxidative stress. Cytochrome P450 epoxygenase metabolites of arachidonic acid, EETs, have multiple cardiovascular effects, including vasodilation, inhibition of inflammatory response and stimulation of epithelial cell growth. In addition, emerging studies indicate a role of these unique lipid mediators in the regulation of metabolic homeostasis. We propose that EET agonists reduce post infarcted cardiac remodeling by improving cardiac dysfunction through increased angiogenesis improved cardiac energy metabolism and a reduction in oxidative stress. Methods: C57B16 mice were divided into 3 groups: sham, mice with myocardial infarction (MI) via LAD ligation and mice with MI treated with an EET-agonist (NUDSA). NUDSA was administered after 5 days of MI (0.5 mg/kg) in C57B16 mice. Myocardial echocardiography was performed 30 days after MI to assess the cardiac function. Capillary density, oxidative stress and cardiac energy metabolism markers were compared among the groups. Results: Echocardiography showed that left ventricle dilatation, measured as end diastolic area (EDA), was reduced in NUDSA treated groups compared to the MI group (C57, EDA: MI: 0.413 ±0.02 cm 2 ; MI+NUDSA: 0.217±0.03 cm 2 ; p<0.05). Cardiac Index, decreased by MI, was restored by NUDSA in C57 mice. Cardiac histological examination revealed an increase in myocardial angiogenesis and capillary density in mice treated with NUDSA (p<0.01 vs. MI). Cardiac tissue showed an increased expression of ETS-1, phosphorylated Acetyl CoA Carboxylase (pACC) and Carnitine Palmitoyl Transferase I (CPT-1) along with a decrease in 3NT and gpphox 91 expression in mice treated with NUDSA as compared to the MI group (p<0.05). Conclusion: This is the first study to demonstrate that EET improves cardiac energy metabolism in infarcted heart by regulating fatty acid oxidation and ameliorating oxidative stress and cardiac remodeling. Thus pharmacological induction of EET may open new avenues in the treatment of patients with post infarcted heart failure.


1999 ◽  
Vol 277 (2) ◽  
pp. E342-E351 ◽  
Author(s):  
John C. Chatham ◽  
Zhi-Ping Gao ◽  
John R. Forder

The aim of this study was to investigate the effect of increasing exogenous palmitate concentration on carbohydrate and palmitate oxidation in hearts from control and 1-wk diabetic rats. Hearts were perfused with glucose, [3-13C]lactate, and [U-13C]palmitate. Substrate oxidation rates were determined by combining13C-NMR glutamate isotopomer analysis of tissue extracts with measurements of oxygen consumption. Carbohydrate oxidation was markedly depressed after diabetes in the presence of low (0.1 mM) but not high (1.0 mM) palmitate concentration. Increasing exogenous palmitate concentration 10-fold resulted in a 7-fold increase in the contribution of palmitate to energy production in controls but only a 30% increase in the diabetic group. Consequently, at 0.1 mM palmitate, the rate of fatty acid oxidation was higher in the diabetic group than in controls; however, at 1.0 mM fatty acid oxidation, it was significantly depressed. Therefore, after 1 wk of diabetes, the major differences in carbohydrate and fatty acid metabolism occur primarily at low rather than high exogenous palmitate concentration.


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