A32 Metabolic capacity and mitochondrial respiration at rest and after physical exercise in huntington’s disease mutation carriers and healthy controls

Metabolic abnormalities and alterations in mitochondrial respiration are described in Huntington’s disease (HD). Since there is great variability concerning disease onset and progression, it is of interest to elucidate the genetic and environmental factors, such as exercise, contributing to this variability. In addition, it is unclear, if mitochondrial dysfunction become evident before onset of neurological manifestation. The aim of this study was to evaluate circulatory, cardiopulmonary and skeletal muscle metabolic responses of HD patients and age-matched controls to acute aerobic exercise. Skeletal muscle biopsies were taken from the M. vastus lateralis at rest and 3 hour after an acute bout of endurance exercise on a cycling ergometer (65% Pmax). The integrated respiratory chain function of the human quadriceps muscle vastus lateralis was measured in freshly taken fine needle biopsies by high-resolution respirometry (HRR). Preliminary results showed that the acute circulatory and skeletal muscle metabolic response to aerobic exercise appears to be blunted in HD patients vs. healthy controls. However, HRR-analysis did not show any changes in mitochondrial respiration before and after exercise comparing healthy controls and HD mutation carriers. Our data show that mitochondrial respiration can be quantified in minimal volume needle biopsies from the M. vastus lateralis of human subjects. This minimal invasive technique can be used to repeat the analysis in short time intervals. In early premanifest HD mutation carriers, mitochondrial respiration and its response to exercise is still unaffected.