Introduction. Mitochondrial diseases (MD) are a wide group of disorders which recognize at their origin a deficient function of the respiratory chain and secondary energy reduction in cells. Aim of this study was to evaluate, in 8 patients affected by different forms of MD, the levels of human mitochondrial transcription factor A (h-mtTFA) in skeletal muscle. H-mtTFA is a 25-KDa nuclear-encoded polypeptide, which plays a relevant role in both replication and transcription of mitochondrial DNA genes. Materials and methods. Eight patients with different forms of MD underwent complete neurological assessment, along with determination of exercise lactate anerobic threshold (LT). Muscle biopsy was performed for histological and histochemical analysis and h-mtTFA level assessment by Western blot. Results. Muscle h-mtTFA levels were significantly reduced in the patients in comparison with a group of controls. The degree of h-mtTFA reduction was related to the LT and the percentage of type 1 fibers with oxidative defects at histochemistry. No correlation between h-mtTFA levels and RRF or COX negative fibers was observed. Conclusions. These results suggest that alterations of the h-mtTFA turnover may be implicated in the pathogenesis of mitochondrial dysfunction in MD patients.
H-MTTFA muscle levels in mitochondrial myopathies.
PASQUALI, LIVIA;MANCUSO, MICHELANGELO;MANCA, MARIA LAURA;ROCCHI, ANNA;SICILIANO, GABRIELE
2000-01-01
Abstract
Introduction. Mitochondrial diseases (MD) are a wide group of disorders which recognize at their origin a deficient function of the respiratory chain and secondary energy reduction in cells. Aim of this study was to evaluate, in 8 patients affected by different forms of MD, the levels of human mitochondrial transcription factor A (h-mtTFA) in skeletal muscle. H-mtTFA is a 25-KDa nuclear-encoded polypeptide, which plays a relevant role in both replication and transcription of mitochondrial DNA genes. Materials and methods. Eight patients with different forms of MD underwent complete neurological assessment, along with determination of exercise lactate anerobic threshold (LT). Muscle biopsy was performed for histological and histochemical analysis and h-mtTFA level assessment by Western blot. Results. Muscle h-mtTFA levels were significantly reduced in the patients in comparison with a group of controls. The degree of h-mtTFA reduction was related to the LT and the percentage of type 1 fibers with oxidative defects at histochemistry. No correlation between h-mtTFA levels and RRF or COX negative fibers was observed. Conclusions. These results suggest that alterations of the h-mtTFA turnover may be implicated in the pathogenesis of mitochondrial dysfunction in MD patients.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.