Abstract for presentation at 11th International Congress of Human Genetics

Oxidative Stress in Maple Syrup Urine Disease Patients

  • Alethea Barschak, Medical Genetics Service, HCPA, Porto Alegre, RS, Brazil; Institute of Biochemistry, ICBS, UFRGS, Porto Alegre, RS, Brazil., Brazil
  • Roberto Giugliani, Medical Genetics Service, Hospital de Clínicas de Porto Alegre, Brazil
  • Angela Sitta, Medical Genetics Service, HCPA, Porto Alegre, RS, Brazil; Institute of Biochemistry, ICBS, UFRGS, Porto Alegre, RS, Brazil., Brazil
  • Marion Deon, Medical Genetics Service, HCPA, Porto Alegre, RS, Brazil; Institute of Biochemistry, ICBS, UFRGS, Porto Alegre, RS, Brazil., Brazil
  • Marcella Oliveira, Medical Genetics Service, HCPA, Porto Alegre, RS, Brazil., Brazil
  • Dr Carlos Dutra Filho, Institute of Biochemistry, ICBS, UFRGS, Porto Alegre, RS, Brazil., Brazil
  • Dr Moacir Wajner, Medical Genetics Service, HCPA, Porto Alegre, RS, Brazil; Institute of Biochemistry, ICBS, UFRGS, Porto Alegre, RS, Brazil., Brazil
  • Dr Carmen Vargas, Medical Genetics Service, HCPA, Porto Alegre, RS, Brazil; Institute of Biochemistry, ICBS, UFRGS, Porto Alegre, RS, Brazil; De, Brazil

    • Maple syrup urine disease (MSUD) or branched-chain alpha-keto aciduria (BCKA) is an inborn error of metabolism caused by a deficiency of the branched-chain alpha-keto acid dehydrogenase complex (BCKAD) activity. The blockage in this enzyme complex leads to tissue accumulation of the branched-chain amino acids (BCAA) leucine, isoleucine and valine. The clinical characterization of this disease includes ketoacidosis, convulsions, coma, psicomotor delay and mental retardation. The mechanism of brain damage is still poorly understood. In recent studies it was demonstrated a significant increase in lipid peroxidation in vitro in cortex of young rats as well as a decrease in the antioxidant defences. In the present study we evaluated different oxidative stress parameters, named reactive species of tiobarbituric acid (TBARS), total antioxidant reactivity (TAR) and total antioxidant status (TAS) in plasma of MSUD patients in diagnosis. We demonstrate a significant increase of plasma TBARS measurements as well as a decrease on plasma TAR. These results indicate an increased lipopreroxidation and a deficient capacity to efficiently modulate the damage associated with an increased production of reactive species. Considering that an unbalance between the total antioxidant defenses and the reactive species formed in the tissues are indicative of oxidative stress, these results may suggest that free radical generation is involved in the pathophysiology of the tissue damage found in MSUD.
    Financial support: (CAPES, FAPERGS, CNPq, PROPESQ/UFRGS, FIPE/HCPA)

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