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Protection of ischaemic myocardium with coenzyme Q10
Insights
Coenzyme Q10 (COQ10) improved adenosine triphosphate (ATP) levels in ischaemic heart muscle during reduced coronary blood flow. COQ10 also lessened negative changes in heart muscle contractions, indicating a protective effect.
Area of Science:
- Cardiology
- Biochemistry
- Pharmacology
Background:
- Myocardial ischemia can lead to significant cellular damage and impaired cardiac function.
- Adenosine triphosphate (ATP) depletion is a key factor in ischemic injury.
- Coenzyme Q10 (COQ10) is an endogenous antioxidant with potential cardioprotective properties.
Purpose of the Study:
- To investigate the protective effects of Coenzyme Q10 (COQ10) on myocardial tissue during ischemia.
- To assess the impact of COQ10 on adenosine triphosphate (ATP) levels and myocardial function in an ischemic model.
Main Methods:
- 38 open-chest mongrel dogs underwent left anterior descending coronary artery constriction to induce ischemia.
- Hemodynamic parameters, including aortic pressure and left ventricular pressure, were monitored.
- Myocardial segment shortening was measured using an ultrasonic dimension gauge.
- Ischemic myocardial biopsies were analyzed for ATP content.
Main Results:
- COQ10 premedication (20 mg/kg IV) significantly preserved ATP content in ischemic myocardium (3.25 ± 0.35 vs. 2.96 ± 0.19 μmol/g wet weight, P < 0.05) when coronary blood flow was reduced by 50-74%.
- COQ10 failed to preserve ATP with further reductions in coronary blood flow.
- COQ10 treatment reduced the impairment of myocardial segment shortening in the ischemic area compared to controls.
- No significant hemodynamic differences were observed between COQ10-treated and control groups.
Conclusions:
- COQ10 demonstrates a protective effect on the ischemic myocardium by preserving ATP levels and mitigating functional deficits at moderate levels of coronary blood flow reduction.
- The cardioprotective effects of COQ10 are likely independent of significant hemodynamic alterations.
- Further research is warranted to explore the efficacy of COQ10 in severe ischemia.
Abstract:
Protection of the ischaemic myocardium with Coenzyme Q10 (COQ10) following constriction of left anterior descending coronary artery was studied in 38 open-chest mongrel dogs. Left anterior descending coronary artery blood flow was independently reduced by tightening a constrictor around the vessel. Aortic pressure and left ventricular pressure were measured, and the Tension Time Index (TTI) was calculated. Myocardial segment shortening in the ischaemic area was measured with an ultrasonic dimension gauge. After obtaining haemodynamic data, the ischaemic myocardium was biopsied and the tissue sample was frozen in liquid nitrogen for adenosine triphosphate (ATP) analysis. Animals premedicated with COQ10 (20 mg . kg-1 iv) had a significantly higher ATP content in ischaemic myocardium (3.25 +/- 0.35 mumol . g-1 wet weight) compared with that in ischaemic myocardium of control animals (2.96 +/- 0.19) (P less than 0.05), when coronary blood flow was reduced by 50 to 74%. There were failure of ATP preservation by COQ10 with a further reduction in coronary blood flow. Changes in the pattern of myocardial segment shortening in the ischemic area induced by a 50 to 74% coronary blood flow reduction were less in COQ10 treated animals than in control animals. Since there were no haemodynamic differences between control and COQ10 treated animals, these effects were considered not to be due to a decrease in myocardial oxygen consumption secondary to haemodynamic changes.