Oxidative stress in plasma from maple syrup urine disease patients during treatment.
Maple Syrup Urine Disease (MSUD) is an autosomal recessive metabolic disorder caused by a deficiency of branched-chain alpha-keto acid dehydrogenase complex activity leading to accumulation of the branched-chain amino acids leucine, isoleucine and valine and their corresponding branched-chain alpha-keto acids. Affected patients usually present hypoglycemia, ketoacidosis, convulsions, poor feeding, coma, psychomotor delay and mental retardation. Considering that the pathophysiology of MSUD is still poorly understood, in this study we evaluated some parameters of oxidative stress, namely thiobarbituric acid-reactive substances (TBARS), total antioxidant reactivity (TAR) and total antioxidant status (TAS) in plasma from treated MSUD patients presenting high and low plasma leucine levels. We verified a significant increase of TBARS (lipid peroxidation) and a decrease of TAR (capacity to rapidly react with free radicals) in plasma from treated MSUD patients with low and with high plasma levels of leucine compared to the control group. It was also verified that TAS (quantity of tissue antioxidants) was not altered in plasma from treated MSUD patients with low and high blood leucine levels. Finally, we found no correlation between leucine, valine and isoleucine levels with the various parameters of oxidative stress. These results are indicative that increased lipid oxidative damage and decreased antioxidant defenses occur in plasma of MSUD patients and that the accumulating branched-chain amino acids are probably not directly associated to oxidative stress in this disorder.
Barschak
Alethéa G
AG
Serviço de Genética Médica, HCPA, Rua Ramiro Barcelos 2350, Porto Alegre, Rio Grande do Sul, Brazil.
Sitta
Angela
A
Deon
Marion
M
Barden
Amanda T
AT
Dutra-Filho
Carlos S
CS
Wajner
Moacir
M
Vargas
Carmen R
CR
D000596:Amino Acids / Q000097:blood; D000975:Antioxidants / Q000378:metabolism; D005260:Female; D006801:Humans; D007202:Indicators and Reagents; D007223:Infant; D007231:Infant, Newborn; D007930:Leucine / Q000097:blood; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D008375:Maple Syrup Urine Disease / Q000097:blood* / Q000628:therapy*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology*; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
D000596:Amino Acids; D000975:Antioxidants; D007202:Indicators and Reagents; D009419:Nerve Tissue Proteins; D017392:Thiobarbituric Acid Reactive Substances; D007930:Leucine