Defective brain energy metabolism shown by in vivo 31P MR spectroscopy in 28 patients with mitochondrial cytopathies.
We studied brain energy metabolism by phosphorus magnetic resonance spectroscopy (31P MRS) in 28 patients with mitochondrial cytopathies, and 20 normal control subjects. Fourteen patients had myopathy alone, six had only mild brain symptoms, and eight showed different degrees of brain involvement. Brain 31P MRS showed a low phosphocreatine content in all patients, accompanied by a high inorganic phosphate in 14 of 28 patients. The average value of the Pi concentration in the patient group was significantly (p = 0.009) different from the control group. The cytosolic pH was normal. From these data were derived a high concentration of ADP (calculated from the creatine kinase equilibrium), a high percent value of V/Vmax for ATP biosynthesis, and a low phosphorylation potential, all features showing a derangement of brain energy metabolism, in all patients with mitochondrial cytopathies. 31P MRS proved to be sensitive enough to disclose a deficit of mitochondrial functionality not only in the affected patients, but also in those without clinically evident brain symptoms.
Barbiroli
B
B
Cattedra di Biochimica Clinica dell'Università di Bologna, Italy.
Montagna
P
P
Martinelli
P
P
Lodi
R
R
Iotti
S
S
Cortelli
P
P
Funicello
R
R
Zaniol
P
P
D000244:Adenosine Diphosphate / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000368:Aged; D001921:Brain / Q000378:metabolism*; D002648:Child; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D017237:Mitochondrial Encephalomyopathies / Q000378:metabolism*; D017240:Mitochondrial Myopathies / Q000378:metabolism*; D009886:Ophthalmoplegia / Q000378:metabolism; D015418:Optic Atrophies, Hereditary / Q000378:metabolism; D009994:Osmolar Concentration; D010725:Phosphocreatine / Q000378:metabolism; D010758:Phosphorus
D010725:Phosphocreatine; D010758:Phosphorus; D000244:Adenosine Diphosphate