Document Detail


Studies of hypoxemic/reoxygenation injury: without aortic clamping. VII. Counteraction of oxidant damage by exogenous antioxidants: coenzyme Q10.
MedLine Citation:
PMID:  7475173     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Coenzyme Q10 (CoQ10) is a natural mitochondrial respiratory chain constituent with antioxidant properties. This study tests the hypothesis that CoQ10 administered before the onset of reoxygenation on cardiopulmonary bypass, can reduce oxygen-mediated myocardial injury and avoid myocardial dysfunction after cardiopulmonary bypass. The antioxidant properties of CoQ10 were confirmed by an in vitro study in which normal myocardial homogenates were incubated with the oxidant, t-butylhydroperoxide. Fifteen immature piglets (< 3 weeks old) were placed on 60 minutes of cardiopulmonary bypass. Five piglets underwent cardiopulmonary bypass without hypoxemia (oxygen tension about 400 mm Hg). Ten others became hypoxemic on cardiopulmonary bypass for 30 minutes by lowering oxygen tension to approximately 25 mm Hg, followed by reoxygenation at oxygen tension about 400 mm Hg for 30 minutes. In five piglets, CoQ10 (45 mg/kg) was added to the cardiopulmonary bypass circuit 15 minutes before reoxygenation, and five others were not treated (no treatment). Myocardial function after cardiopulmonary bypass was evaluated from end-systolic elastance (conductance catheter), oxidant damage (lipid peroxidation) was assessed by measuring conjugated diene levels in coronary sinus blood, and antioxidant reserve capacity was determined by measuring malondialdehyde in myocardium after cardiopulmonary bypass incubated in the oxidant, t-butylhydroperoxide. Cardiopulmonary bypass without hypoxemia caused no oxidant damage and allowed complete functional recovery. Reoxygenated hearts (no treatment) showed a progressive increase in conjugated diene levels in coronary sinus blood after reoxygenation (2.3 +/- 0.6 A233 nm/0.5 ml plasma at 30 minutes after reoxygenation) and reduced antioxidant reserve capacity (malondialdehyde: 1219 +/- 157 nmol/g protein at 4.0 mmol/L t-butylhydroperoxide), resulting in severe postbypass dysfunction (percent end-systolic elastance = 38 +/- 6). Conversely, CoQ10 treatment avoided the increase in conjugated diene levels (2.1 +/- 0.6 vs 1.1 +/- 0.3, p < 0.05 vs no treatment), retained normal antioxidant reserve (896 +/- 76 nmol/g protein, p < 0.05 vs no treatment), and allowed nearly complete recovery of function (94% +/- 7%, p < 0.05 vs no treatment). We conclude that reoxygenation of the hypoxemic immature heart on cardiopulmonary bypass causes oxygen-mediated myocardial injury, which can be limited by CoQ10 treatment before reoxygenation. These findings imply that coenzyme Q10 can be used to surgical advantage in cyanotic patients, because therapeutic blood levels can be achieved by preoperative oral administration of this approved drug.
Authors:
K Morita; K Ihnken; G D Buckberg; H H Young
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of thoracic and cardiovascular surgery     Volume:  110     ISSN:  0022-5223     ISO Abbreviation:  J. Thorac. Cardiovasc. Surg.     Publication Date:  1995 Oct 
Date Detail:
Created Date:  1995-11-28     Completed Date:  1995-11-28     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0376343     Medline TA:  J Thorac Cardiovasc Surg     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1221-7     Citation Subset:  AIM; IM    
Affiliation:
Department of Surgery, University of California, Los Angeles School of Medicine 90024-1741, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Anoxia / complications*,  etiology,  metabolism,  physiopathology
Cardiopulmonary Bypass / adverse effects*,  methods
Coenzymes
Hemodynamics / drug effects
Lipid Peroxidation / drug effects
Myocardial Contraction / drug effects
Myocardial Reperfusion Injury / etiology,  metabolism*,  physiopathology,  prevention & control*
Peroxides / antagonists & inhibitors*
Reactive Oxygen Species*
Swine
Ubiquinone / analogs & derivatives*,  pharmacology
Ventricular Function, Left / drug effects
tert-Butylhydroperoxide
Chemical
Reg. No./Substance:
0/Coenzymes; 0/Peroxides; 0/Reactive Oxygen Species; 1339-63-5/Ubiquinone; 303-98-0/coenzyme Q10; 75-91-2/tert-Butylhydroperoxide

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