188 - Over Antioxidation, in Addition to Oxidative Stress, Contributes to the Pathogenesis of Autism Spectrum Disorders in Children

Abstract

Oxidative stress is currently recognized to play a central role in the pathogenesis of autism spectrum disorders (ASD). However, oxidative stress markers and antioxidant measures yield variable results and the overall picture remains obscure. Previously, we have reported a shift in radical scavenging activity in SfRBM2016. In this study, we evaluate further the comprehensive oxidative and antioxidative status in ASD children. The study enrolled 22 children with ASD (3.73 ± 0.17 years old [mean ±SEM]), diagnosed by the specialist of autism, and 31 age-matched healthy control children under typical development (TD, 4.43 ± 0.23 years old). Using an electron spin resonance (ESR)-based method we found a decrease of serum scavenging activity against hydroxyl radicals in ASD (55% of TD) while those against superoxide and alkoxyl radicals were significantly increased (120% and 157% of TD, respectively). The ASD group showed significantly higher serum 8-hydroxy-2'-deoxyguanosine (8-OHdG) and higher ubiquinone values than those of the TD (136% and 133% of TD, respectively). In contrast, the serum adiponectin values were significantly elevated in the ASD group (130% of TD). Serum α-tocopherol levels of the both groups were within the reference range for the corresponding age while that of the ASD was significantly higher than that in the TD (116%). There were no significant differences between the two groups in serum peroxyl radicals and singlet oxygen scavenging activity, or levels of ubiquinol, total CoQ10 or CRP. These results strongly suggest an upsurge in both oxidative and antioxidative mechanisms in ASD children. Together with our results and previous reports indicating abnormality of glutathione system, a decrease in the protection against the hydroxyl radical may be a fundamental mechanism in ASD leading to a shift of oxidative reactions involving tocopherols and the adiponectin system.