Increased Lipid Peroxidation in Cerebellum and Temporal Cortex in Autism

Background: Accumulating evidence suggests that oxidative stress may provide a link between susceptibility genes and pre- and post-natal environmental stressors in the pathophysiology of autism. Brain tissue is highly heterogeneous with different functions localized in specific areas. Studies on oxidative stress in relation to specific regions of the brain are lacking in autism.

Objectives: In this study, the status of lipid peroxidation was compared in postmortem brain samples from the cerebellum and frontal, temporal, parietal and occipital cortex from autistic subjects with age range of 4 to 39 yrs (N = 7-10 for different brain regions) and age-matched normal subjects (N =  9-10).

Methods: The levels of malonyldialdehyde (MDA), an end product of fatty acid oxidation, were assayed in the brain homogenates from autism and control subjects.

Results: MDA levels were significantly increased by 124 % in the cerebellum and by 256 % in the temporal cortex in autism as compared to control subjects. No overlap of MDA levels was observed in the temporal cortex between autism and control groups. In the cerebellum, 57 % of autism subjects had MDA levels above the cutoff value (upper range for control group). In contrast, no significant change in MDA levels was observed in frontal, occipital and parietal cortex between autism and control groups.

Conclusions: These results suggest that oxidative stress differentially affects selective regions of the brain, i.e. cerebellum and temporal cortex, in autism.