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Houston, TX, United States

Gupte A.A.,Methodist Diabetes and Metabolism Institute | Minze L.J.,Methodist Diabetes and Metabolism Institute | Reyes M.,Methodist Diabetes and Metabolism Institute | Ren Y.,Methodist Diabetes and Metabolism Institute | And 11 more authors.

In obesity, reduced cardiac glucose uptake and mitochondrial abnormalities are putative causes of cardiac dysfunction. However, high-fat diet (HFD) does not consistently induce cardiac insulin resistance and mitochondrial damage, and recent studies suggest HFD may be cardioprotective. To determine cardiac responses to HFD, we investigated cardiac function, glucose uptake, and mitochondrial respiration in young (3-month-old) and middle-aged (MA) (12-month-old) male Ldlrβ/β mice fed chow or 3 months HFD to induce obesity, systemic insulin resistance, and hyperinsulinemia. In MA Ldlr -1 mice, HFD induced accelerated atherosclerosis and nonalcoholic steatohepatitis, commoncomplications of human obesity. Surprisingly, HFD-fed mice demonstrated increased cardiac glucose uptake, whichwasmost prominent inMAmice, in the absence of cardiac contractile dysfunction or hypertrophy. Moreover, hearts of HFD-fed mice had enhanced mitochondrial oxidation of palmitoyl carnitine, glutamate, and succinate and greater basal insulin signaling compared with those of chow-fed mice, suggesting cardiac insulin sensitivity was maintained, despite systemic insulin resistance. Streptozotocin-induced ablation of insulin production markedly reduced cardiac glucose uptake and mitochondrial dysfunction in HFD-fed, but not in chow-fed, mice. Insulin injection reversed these effects, suggesting that insulin may protect cardiac mitochondria during HFD. These results have implications for cardiac metabolism and preservation of mitochondrial function in obesity. © 2013 by The Endocrine Society. Source

Collins A.R.,Methodist Hospital Research Institute | Collins A.R.,New York Medical College | Gupte A.A.,Methodist Hospital Research Institute | Gupte A.A.,New York Medical College | And 19 more authors.
Arteriosclerosis, Thrombosis, and Vascular Biology

OBJECTIVE-: To determine the impact of hematopoietic deletion of nuclear factor- (erythroid-derived 2) like 2 factor (Nrf2) on the development of atherosclerosis and liver injury in an obese, hypercholesterolemic mouse model. METHODS AND RESULTS-: Two-month-old male low-density lipoprotein receptor-deficient mice were lethally irradiated and transplanted with either wild type or Nrf2-deficient (Nrf2) bone marrow cells. At 3 months of age, mice were placed on an obesogenic high-fat diet (HFD), high-cholesterol diet for 7 months. Despite no differences in body weight, body fat percentage, liver fat, plasma glucose, lipids, or insulin, the HFD-fed Nrf2 bone marrow recipients had increased proinflammatory vascular gene expression, a significant increase in atherosclerosis area (18% versus 28%; P=0.018) and lesion complexity, and a marked increase in liver fibrosis. The acceleration of vascular and liver injury may arise from enhanced macrophage migration, inflammation, and oxidative stress resulting from myeloid Nrf2 deficiency. CONCLUSION-: Myeloid-derived Nrf2 activity attenuates atherosclerosis development and liver inflammation and fibrosis associated with obesity. Prevention of oxidative stress in macrophage and other myeloid lineage cells may be an important therapeutic target to reduce inflammation-driven complications of obesity. © 2012 American Heart Association, Inc. Source

Gupte A.A.,Methodist Diabetes and Metabolism Institute | Gupte A.A.,New York Medical College | Hamilton D.J.,Methodist Diabetes and Metabolism Institute | Hamilton D.J.,New York Medical College | And 26 more authors.
Circulation: Cardiovascular Genetics

Background-Impaired bioenergetics is a prominent feature of the failing heart, but the underlying metabolic perturbations are poorly understood. Methods and Results-We compared metabolomic, gene transcript, and protein data from 6 paired samples of failing human left ventricular tissue obtained during left ventricular assist device insertion (heart failure samples) and at heart transplant (post-left ventricular assist device samples). Nonfailing left ventricular wall samples procured from explanted hearts of patients with right heart failure served as novel comparison samples. Metabolomic analyses uncovered a distinct pattern in heart failure tissue: 2.6-fold increased pyruvate concentrations coupled with reduced Krebs cycle intermediates and short-chain acylcarnitines, suggesting a global reduction in substrate oxidation. These findings were associated with decreased transcript levels for enzymes that catalyze fatty acid oxidation and pyruvate metabolism and for key transcriptional regulators of mitochondrial metabolism and biogenesis, peroxisome proliferator-Activated receptor ? coactivator 1a (PGC1A, 1.3-fold) and estrogen-related receptor a (ERRA, 1.2-fold) and ? (ERRG, 2.2-fold). Thus, parallel decreases in key transcription factors and their target metabolic enzyme genes can explain the decreases in associated metabolic intermediates. Mechanical support with left ventricular assist device improved all of these metabolic and transcriptional defects. Conclusions-These observations underscore an important pathophysiologic role for severely defective metabolism in heart failure, while the reversibility of these defects by left ventricular assist device suggests metabolic resilience of the human heart. © 2014 American Heart Association, Inc. Source

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