Exogenous coenzyme Q (CoQ) fails to increase CoQ in skeletal muscle of two patients with mitochondrial myopathies

Abstract

Recently, several studies were published on therapy with coenzyme Q (CoQ) in patients with mitochondrial myopathies without biochemically established muscular deficiency of CoQ. Two patients with mitochondrial myopathies presenting as oculocraniosomatic syndromes were treated with coenzyme Q (CoQ). The muscle biopsy of both patients showed ragged-red fibers and single muscle fibers without histochemical reaction for cytochrome c oxidase. Biochemical analysis revealed normal activities of the respiratory chain complexes in muscle and normal levels of CoQ in serum and muscle. After one year of treatment CoQ in serum of both patients had increased 1.4-fold and 2.0-fold, respectively. In muscle, however, there was no increase of CoQ in either patient. In both patients the activities of citrate synthase and of the respiratory chain complexes I+III and IV, and in 1 patient also of complex II+III, were lower in the second biopsy compared with the first biopsy. In both patients there was no improvement of maximal isometric muscle strength assessed by a quantitative electronic strain gauge. The exercise-induced pathological rise of lactate in 1 patient remained essentially unchanged during therapy. The data indicate that orally administered CoQ fails to increase total CoQ in muscle of patients with mitochondrial myopathies but without muscular CoQ deficiency.