Coenzyme Q10 treatment improves the tolerance of the senescent myocardium to pacing stress in the rat.

Objective: In elderly patients the results of cardiac interventions are inferior to those in the young. A possible contributing factor is an age-related reduction in cellular energy transduction during the intervention which may induce aerobic or ischemic stress. To investigate whether coenzyme Q10 (CoQ10) improves the response to aerobic stress, functional recoveries of senescent and young rat hearts after rapid pacing were compared with or without CoQ10.
Methods: Young (4.8 +/- 0.1 months) and senescent (35.3 +/- 0.2 months) rats were given daily intraperitoneal injections of CoQ10 (4 mg/kg) or vehicle for 6 weeks. Their isolated hearts were rapidly paced at 510 beats per minute for 120 min to induce aerobic stress without ischemia.
Results: In senescent hearts pre-pacing cardiac work was 74% and oxygen consumption (MVO2) 66% of that in young hearts. CoQ10 treatment abolished these differences. After pacing, the untreated senescent hearts, compared to young, showed reduced recovery of pre-pacing work, (16.8 +/- 4.3 vs. 44.5 +/- 7.4%; P < 0.01). CoQ10 treatment in senescent hearts improved recovery of work, (48.1 +/- 4.1 vs. 16.8 +/- 4.3%; P < 0.0001) and MVO2 (82.1 +/- 2.8 vs. 61.3 +/- 4.0%; P < 0.01) in treated versus untreated hearts respectively. Post-pacing levels of these parameters in CoQ10 treated senescent hearts were as high as in young hearts.
Conclusions: (1) Senescent rat hearts have reduced baseline function and reduced tolerance to aerobic stress compared to young hearts. (2) Pre-treatment with CoQ10 improves baseline function of the senescent myocardium and its tolerance to aerobic stress.