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Karwi QG, Uddin GM, Ho KL, Lopaschuk GD. Loss of Metabolic Flexibility in the Failing Heart. Front Cardiovasc Med 2018; 5:68. [PMID: 29928647 PMCID: PMC5997788 DOI: 10.3389/fcvm.2018.00068] [Citation(s) in RCA: 248] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 05/18/2018] [Indexed: 12/15/2022] Open
Abstract
To maintain its high energy demand the heart is equipped with a highly complex and efficient enzymatic machinery that orchestrates ATP production using multiple energy substrates, namely fatty acids, carbohydrates (glucose and lactate), ketones and amino acids. The contribution of these individual substrates to ATP production can dramatically change, depending on such variables as substrate availability, hormonal status and energy demand. This "metabolic flexibility" is a remarkable virtue of the heart, which allows utilization of different energy substrates at different rates to maintain contractile function. In heart failure, cardiac function is reduced, which is accompanied by discernible energy metabolism perturbations and impaired metabolic flexibility. While it is generally agreed that overall mitochondrial ATP production is impaired in the failing heart, there is less consensus as to what actual switches in energy substrate preference occur. The failing heart shift toward a greater reliance on glycolysis and ketone body oxidation as a source of energy, with a decrease in the contribution of glucose oxidation to mitochondrial oxidative metabolism. The heart also becomes insulin resistant. However, there is less consensus as to what happens to fatty acid oxidation in heart failure. While it is generally believed that fatty acid oxidation decreases, a number of clinical and experimental studies suggest that fatty acid oxidation is either not changed or is increased in heart failure. Of importance, is that any metabolic shift that does occur has the potential to aggravate cardiac dysfunction and the progression of the heart failure. An increasing body of evidence shows that increasing cardiac ATP production and/or modulating cardiac energy substrate preference positively correlates with heart function and can lead to better outcomes. This includes increasing glucose and ketone oxidation and decreasing fatty acid oxidation. In this review we present the physiology of the energy metabolism pathways in the heart and the changes that occur in these pathways in heart failure. We also look at the interventions which are aimed at manipulating the myocardial metabolic pathways toward more efficient substrate utilization which will eventually improve cardiac performance.
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Affiliation(s)
| | | | | | - Gary D. Lopaschuk
- Cardiovascular Research Centre, University of Alberta, Edmonton, AB, Canada
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Siasos G, Tsigkou V, Kosmopoulos M, Theodosiadis D, Simantiris S, Tagkou NM, Tsimpiktsioglou A, Stampouloglou PK, Oikonomou E, Mourouzis K, Philippou A, Vavuranakis M, Stefanadis C, Tousoulis D, Papavassiliou AG. Mitochondria and cardiovascular diseases-from pathophysiology to treatment. ANNALS OF TRANSLATIONAL MEDICINE 2018; 6:256. [PMID: 30069458 DOI: 10.21037/atm.2018.06.21] [Citation(s) in RCA: 162] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Mitochondria are the source of cellular energy production and are present in different types of cells. However, their function is especially important for the heart due to the high demands in energy which is achieved through oxidative phosphorylation. Mitochondria form large networks which regulate metabolism and the optimal function is achieved through the balance between mitochondrial fusion and mitochondrial fission. Moreover, mitochondrial function is upon quality control via the process of mitophagy which removes the damaged organelles. Mitochondrial dysfunction is associated with the development of numerous cardiac diseases such as atherosclerosis, ischemia-reperfusion (I/R) injury, hypertension, diabetes, cardiac hypertrophy and heart failure (HF), due to the uncontrolled production of reactive oxygen species (ROS). Therefore, early control of mitochondrial dysfunction is a crucial step in the therapy of cardiac diseases. A number of anti-oxidant molecules and medications have been used but the results are inconsistent among the studies. Eventually, the aim of future research is to design molecules which selectively target mitochondrial dysfunction and restore the capacity of cellular anti-oxidant enzymes.
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Affiliation(s)
- Gerasimos Siasos
- Department of Cardiology, "Hippokration" General Hospital, National and Kapodistrian University of Athens, School of Medicine, Athens, Greece.,Division of Cardiovascular, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Vasiliki Tsigkou
- Department of Cardiology, "Hippokration" General Hospital, National and Kapodistrian University of Athens, School of Medicine, Athens, Greece
| | - Marinos Kosmopoulos
- Department of Cardiology, "Hippokration" General Hospital, National and Kapodistrian University of Athens, School of Medicine, Athens, Greece
| | - Dimosthenis Theodosiadis
- Department of Cardiology, "Hippokration" General Hospital, National and Kapodistrian University of Athens, School of Medicine, Athens, Greece
| | - Spyridon Simantiris
- Department of Cardiology, "Hippokration" General Hospital, National and Kapodistrian University of Athens, School of Medicine, Athens, Greece
| | - Nikoletta Maria Tagkou
- Department of Cardiology, "Hippokration" General Hospital, National and Kapodistrian University of Athens, School of Medicine, Athens, Greece
| | - Athina Tsimpiktsioglou
- Department of Cardiology, "Hippokration" General Hospital, National and Kapodistrian University of Athens, School of Medicine, Athens, Greece
| | - Panagiota K Stampouloglou
- Department of Cardiology, "Hippokration" General Hospital, National and Kapodistrian University of Athens, School of Medicine, Athens, Greece
| | - Evangelos Oikonomou
- Department of Cardiology, "Hippokration" General Hospital, National and Kapodistrian University of Athens, School of Medicine, Athens, Greece
| | - Konstantinos Mourouzis
- Department of Cardiology, "Hippokration" General Hospital, National and Kapodistrian University of Athens, School of Medicine, Athens, Greece
| | - Anastasios Philippou
- Department of Experimental Physiology, Medical School, National and Kapodistrian University of Athens, Greece
| | - Manolis Vavuranakis
- Department of Cardiology, "Hippokration" General Hospital, National and Kapodistrian University of Athens, School of Medicine, Athens, Greece
| | | | - Dimitris Tousoulis
- Department of Cardiology, "Hippokration" General Hospital, National and Kapodistrian University of Athens, School of Medicine, Athens, Greece
| | - Athanasios G Papavassiliou
- Department of Biological Chemistry, National and Kapodistrian University of Athens, School of Medicine, Athens, Greece
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