Impaired coronary metabolic dilation in the metabolic syndrome is linked to mitochondrial dysfunction and mitochondrial DNA damage.
Animal; Animals; Coronary circulation; Coronary microcirculation; Coronary Vessels/metabolism/*physiopathology; Diabetes; Disease Models; DNA; DNA Damage/physiology; DNA Fragmentation; Metabolic Syndrome/metabolism/*physiopathology; Mitochondria; Mitochondria/*metabolism; Mitochondrial/*metabolism; Obesity; Oxidative Stress/physiology; Rats; Reactive Oxygen Species/metabolism; Vasodilation/physiology; Zucker
Mitochondrial dysfunction in obesity and diabetes can be caused by excessive production of free radicals, which can damage mitochondrial DNA. Because mitochondrial DNA plays a key role in the production of ATP necessary for cardiac work, we hypothesized that mitochondrial dysfunction, induced by mitochondrial DNA damage, uncouples coronary blood flow from cardiac work. Myocardial blood flow (contrast echocardiography) was measured in Zucker lean (ZLN) and obese fatty (ZOF) rats during increased cardiac metabolism (product of heart rate and arterial pressure, i.v. norepinephrine). In ZLN increased metabolism augmented coronary blood flow, but in ZOF metabolic hyperemia was attenuated. Mitochondrial respiration was impaired and ROS production was greater in ZOF than ZLN. These were associated with mitochondrial DNA (mtDNA) damage in ZOF. To determine if coronary metabolic dilation, the hyperemic response induced by heightened cardiac metabolism, is linked to mitochondrial function we introduced recombinant proteins (intravenously or intraperitoneally) in ZLN and ZOF to fragment or repair mtDNA, respectively. Repair of mtDNA damage restored mitochondrial function and metabolic dilation, and reduced ROS production in ZOF; whereas induction of mtDNA damage in ZLN reduced mitochondrial function, increased ROS production, and attenuated metabolic dilation. Adequate metabolic dilation was also associated with the extracellular release of ADP, ATP, and H2O2 by cardiac myocytes; whereas myocytes from rats with impaired dilation released only H2O2. In conclusion, our results suggest that mitochondrial function plays a seminal role in connecting myocardial blood flow to metabolism, and integrity of mtDNA is central to this process.
Guarini Giacinta; Kiyooka Takahiko; Ohanyan Vahagn; Pung Yuh Fen; Marzilli Mario; Chen Yeong-Renn; Chen Chwen-Lih; Kang Patrick T; Hardwick James P; Kolz Christopher L; Yin Liya; Wilson Glenn L; Shokolenko Inna; Dobson James G Jr; Fenton Richard; Chilian William M
Basic research in cardiology
2016
2016-05
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1007/s00395-016-0547-4" target="_blank" rel="noreferrer noopener">10.1007/s00395-016-0547-4</a>
Myocardial ischemia: From disease to syndrome.
Angina; Chronic coronary syndromes; Coronary artery disease; Ischemic heart disease; Microvascular dysfunction
Although current guidelines on the management of stable coronary artery disease acknowledge that multiple mechanisms may precipitate myocardial ischemia, recommended diagnostic, prognostic and therapeutic algorithms are still focused on obstructive epicardial atherosclerotic lesions, and little progress has been made in identifying management strategies for non-atherosclerotic causes of myocardial ischemia. The purpose of this consensus paper is three-fold: 1) to marshal scientific evidence that obstructive atherosclerosis can co-exist with other mechanisms of ischemic heart disease (IHD); 2) to explore how the awareness of multiple precipitating mechanisms could impact on pre-test probability, provocative test results and treatment strategies; and 3) to stimulate a more comprehensive approach to chronic myocardial ischemic syndromes, consistent with the new understanding of this condition.
Marzilli Mario; Crea Filippo; Morrone Doralisa; Bonow Robert O; Brown David L; Camici Paolo G; Chilian William M; DeMaria Anthony; Guarini Giacinta; Huqi Alda; Merz C Noel Bairey; Pepine Carl; Scali Maria Chiara; Weintraub William S; Boden William E
International journal of cardiology
2020
2020-04-26
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
journalArticle
<a href="http://doi.org/10.1016/j.ijcard.2020.04.074" target="_blank" rel="noreferrer noopener">10.1016/j.ijcard.2020.04.074</a>