Antioxidant enzymes and lipid peroxides in children with Down syndrome

Impaired antioxidant mechanisms lead to an increase in free radicals and may induce a number of pathophysiological processes resulting in cell injury. Thus, any abnormality in antioxidant systems could affect neurodevelopmental processes and could have an important role in the pathogenesis of Down syndrome (DS). The plasma levels of lipid peroxidation factors such as plasma levels of malondialdehyde, activities of superoxide dismutase, glutathione peroxidase, and glutathione reductase in serum were investigated in 41 DS children and were compared with 61 healthy controls. Superoxide dismutase, glutathione peroxidase and glutathione reductase activities were spectrophotometrically assayed. Serum activities of superoxide dismutase and glutathione reductase did not differ significantly between DS children and the control group. Malondialdehyde concentrations did not differ statistically between the DS children and healthy subjects. We found a significant increase of glutathione peroxidase activity in the sera of children with DS compared to the controls. Our results suggest that an increase in serum glutathione peroxidase activity could be a suitable protective mechanism against peroxidation processes in DS patients.