P-31 NMR-SPECTROSCOPY AND ERGOMETER EXERCISE TEST AS EVIDENCE FOR MUSCLE OXIDATIVE PERFORMANCE IMPROVEMENT WITH COENZYME-Q IN MITOCHONDRIAL MYOPATHIES

Two patients with mitochondrial encephalomyopathy due to complexes I and IV deficiencies received 150 mg/d of coenzyme Q10 (CoQ). We studied them with a bicycle ergometer exercise test and P-31 NMR spectroscopy before and after 10 months of treatment. Before treatment, we observed a low phosphocreatine/inorganic phosphate (PCr/P(i)) resting value along with abnormally high resting lactate concentration. During exercise, there was a pronounced acidosis with delayed kinetics of postexercise recovery for blood lactate, pH, PCr, and PCr/P(i) ratio. Oxygen uptake during exercise was reduced while the lowering of the ventilatory threshold indicated an early activation of glycolysis. After treatment, the bicycle ergometer exercise test indicated a significant improvement with a decrease in resting blood lactate level, an increase in oxygen consumption during exercise, and an increase in the kinetics of lactate disappearance during the recovery period. A shift of the ventilatory threshold to higher workload was present. P-31 NMR spectroscopy confirmed the improvement, showing a significant increase in the PCr/P(i) ratio at rest and in the kinetics of recovery for pH, PCr, and PCr/P(i) ratio folLowing exercise in patient 1. For patient 2, we observed a less pronounced acidosis correlated with a lesser amount of P(i) produced during exercise. These observations indicate an improvement of mitochondrial function and a shift from high to low glycolytic activity in both patients consequent to CoQ treatment.