COENZYME Q(10) TREATMENT IMPROVES THE TOLERANCE OF THE SENESCENT MYOCARDIUM TO PACING STRESS IN THE RAT

Objective: In elderly patients the results of cardiac interventions ar e inferior to those in the young. A possible contributing factor is an age-related reduction in cellular energy transduction during the inte rvention which may induce aerobic or ischemic stress. To investigate w hether coenzyme Q(10) (CoQ(10)) improves the response to aerobic stres s, functional recoveries of senescent and young rat hearts after rapid pacing were compared with or without CoQ(10). Methods: Young (4.8+/-0 .1 months) and senescent (35.3+/-0.2 months) rats were given daily int raperitoneal injections of CoQ(10) (4 mg/kg) or vehicle for 6 weeks. T heir isolated hearts were rapidly paced at 510 beats per minute for 12 0 min to induce aerobic stress without ischemia. Results: Zn senescent hearts pre-pacing cardiac work was 74% and oxygen consumption (MVO2) 66% of that in young hearts. CoQ(10) treatment abolished these differe nces. 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). Coo,, 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 CoQ(10) treated senescent he arts were as high as in young hearts. Conclusions: (1) Senescent rat h earts have reduced baseline function and reduced tolerance to aerobic stress compared to young hearts. (2) Pre-treatment with CoQ(10) improv es baseline function of the senescent myocardium and its tolerance to aerobic stress. (C) 1998 Elsevier Science B.V. All rights reserved.