Oxidative stress biomarkers in mitochondrial myopathies, basally and after cysteine donor supplementation.
Mitochondrial diseases are due to impairment of the mitochondrial respiratory chain. A plausible pathogenic mechanism leading to cellular dysfunction and phenotypic expression is oxidative stress, but there are surprisingly few clinical studies on this subject. Glutathione (GSH) deficiency has been reported in mitochondrial diseases, and the biosynthesis of glutathione depends on cysteine availability. We have examined oxidative stress biomarkers [advanced oxidation protein products (AOPP) and ferric reducing antioxidant power (FRAP)] in blood samples from 27 patients and 42 controls. AOPP levels were greater in patients than in controls (P value <0.00001). Therefore, we performed a double-blind cross-over study to evaluate if 30-day supplementation with a whey-based cysteine donor could modify these markers, reduce lactate concentration during aerobic exercise, or enhance muscular strength and quality of life. Treatment did not modify lactate concentration, clinical scale (MRC) or quality of life (SF-36), but significantly reduced oxidative stress levels. Our findings reinforce the notions that in mitochondrial diseases oxidative stress is important and can be reduced by administration of a cysteine donor. Oxidative stress biomarkers may be useful to detect redox imbalance in mitochondrial diseases and to provide non-invasive tools to monitor disease status.
Mancuso
Michelangelo
M
Department of Neuroscience, Neurological Clinic, University of Pisa, Via Roma 67, 56126 Pisa, Italy. mmancuso@inwind.it
Orsucci
Daniele
D
Logerfo
Annalisa
A
Rocchi
Anna
A
Petrozzi
Lucia
L
Nesti
Claudia
C
Galetta
Fabio
F
Santoro
Gino
G
Murri
Luigi
L
Siciliano
Gabriele
G
D000975:Antioxidants / Q000008:administration & dosage / Q000627:therapeutic use; D015415:Biomarkers / Q000097:blood; D018592:Cross-Over Studies; D003545:Cysteine / Q000008:administration & dosage* / Q000627:therapeutic use; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D008297:Male; D008875:Middle Aged; D017240:Mitochondrial Myopathies / Q000097:blood* / Q000188:drug therapy; D018384:Oxidative Stress; D011788:Quality of Life; D012720:Severity of Illness Index; D016896:Treatment Outcome
D000975:Antioxidants; D015415:Biomarkers; D019344:Lactic Acid; D003545:Cysteine