Redox balance in patients with Down's syndrome before and after dietary supplementation with alpha-lipoic acid and L-cysteine.

The aim of the present study was to investigate the possible normalizing effect of antioxidants on certain parameters indicative of oxidative stress in Down's syndrome (DS). The study was performed in pediatric patients with DS with proven redox imbalance, who were advised to take a dietary supplementation composed of alpha-lipoic acid and L-cysteine for several treatment cycles (one treatment cycle = 30 days dietary supplementation plus 30 days wash-out). Serum thiol groups, serum total and septic reactive oxygen species (ROS) and total antioxidant status of serum were determined before and after dietary supplementation, using commercially available kits. In all the evaluable patients (n = 20), after 3.8 +/- 1.1 treatment cycles, thiol group serum concentrations and total antioxidant status of serum significantly increased (p < 0.0001 for both parameters) in comparison with basal values, while serum total and septic ROS significantly decreased (p < 0.0001 for both parameters). On the basis of these results it is impossible to demonstrate the clinical effects of the biochemical normalization obtained in patients with DS after supplying alpha-lipoic acid and L-cysteine. These data suggest that delaying the clinical expression of redox imbalance in patients with DS might be feasible by normalizing their redox balance.