Oxidative stress is a phenomenon associated with imbalance between production of free radicals and reactive metabolites (e.g. superoxide and hydrogen peroxide) and the antioxidant defences. Oxidative stress in individuals with Down syndrome (DS) has been associated with trisomy of the 21st chromosome resulting in DS phenotype as well as with various morphological abnormalities, immune disorders, intellectual disability, premature aging and other biochemical abnormalities. Trisomy 21 in patients with DS results in increased activity of an important antioxidant enzyme Cu/Zn superoxide dismutase (SOD) which gene is located on the 21st chromosome along with other proteins such as transcription factor Ets-2, stress inducing factors (DSCR1) and precursor of beta-amyloid protein responsible for the formation of amyloid plaques in Alzheimer disease. Mentioned proteins are involved in the management of mitochondrial function, thereby promoting mitochondrial theory of aging also in people with DS. In defence against toxic effects of free radicals and their metabolites organism has built antioxidant defence systems. Their lack and reduced function increases oxidative stress resulting in disruption of the structure of important biomolecules, such as proteins, lipids and nucleic acids. This leads to their dysfunctions affecting pathophysiology of organs and the whole organism. This paper examines the impact of antioxidant interventions as well as positive effect of physical exercise on cognitive and learning disabilities of individuals with DS. Potential terapeutic targets on the molecular level (oxidative stress markers, gene for DYRK1A, neutrophic factor BDNF) after intervention of natural polyphenols are also discussed., J. Muchová, I Žitňanová, Z. Ďuračková., and Obsahuje bibliografii
In subjects with Down¢ s syndrome (DS) increased oxidative stress and consequent oxidative cell damage have been reported. The aim of this study was to assess whether the excessive production of free oxygen radicals in these subjects can affect the copper-induced lipid oxidation resistance measured in fresh whole serum. Since a significant elevation of serum uric acid levels, which is an efficient hydrophilic antioxidant, has been repeatedly reported in subjects with DS, we studied the association between increased serum uric acid levels and lipid resistance to oxidation measured directly in serum samples by monitoring the change in absorbance at 234 nm. The group of subjects with Down¢ s syndrome consisted of 25 individuals (aged 18± 5 years). Control group included brothers and sisters of subjects with DS (n = 25, aged 17± 7 years). In subjects with DS, the serum lipid resistance to oxidation (lag time) was significantly higher than in controls (p< 0.05) and a concomitant increase in serum uric acid levels was observed (p< 0.001). A significant positive correlation between lag time and serum uric acid concentration was found in subjects with DS (r = 0.48, p< 0.05), while the positive correlation in the control group was not significant. The results suggest that increased serum uric acid levels repeatedly observed in subjects with DS may be associated with an enhanced resistance of serum lipids to oxidation which is thought to play an important role in the atherogenic process., A. Nagyová, M. Šustrová, K. Rašlová., and Obsahuje bibliografii