Dr. Ved Chauhan Environmental Symposium: Oxidative Stress and Mitochondrial Abnormalities

We studied the status of oxidative stress in the lymphoblasts from autistic and control subjects by analyzing lipid peroxidation, activities of enzymes involved in antioxidant defense, generation of free radicals (reactive oxygen species: ROS), and extent of membrane damage. While lipid peroxidation and ROS levels were increased, the activities of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase were decreased in autistic lymphoblasts, which suggest increased oxidative damage coupled with impaired antioxidant defense mechanism in autism. Furthermore, membrane fluidity was decreased and lactate dehydrogenase leakage was increased in the autistic lymphoblasts compared with controls, suggesting that membrane integrity and function are affected in autism. In addition, the mitochondrial membrane potential (MMP) was reduced in autistic lymphoblasts. Environmental agents such as bisphenol A, endosulfan, and thimerosal have been suggested to play a role in the etiology of autism. However, the mechanism of their action is not known. Therefore, we studied their effect on the membrane properties and MMP. Our results show that these environmental agents decrease both membrane fluidity and MMP. These results suggest that autism is associated with increased formation of free radicals coupled with decreased activities of antioxidant enzymes, which leads to increased oxidative damage, membrane damage, and mitochondrial abnormalities.
 
Ved Chauhan, PhD is head of the cellular neurochemistry laboratory at the New York State Institute for Basic Research in Developmental Disabilities (IBR), Staten Island, New York. Dr. Chauhan received his PhD (Biochemistry) from the Postgraduate Institute for Medical Education and Research, Chandigarh, India. After working as a research associate for 2 years in the Department of Biochemistry at the University of Southern California, Los Angeles, he joined IBR as a research scientist.
 
Dr. Chauhan has received several research grants as PI and Co-PI from the NIH, Autism Speaks, the Autism Research Institute, the Autism Collaboration, and Cure Autism Now. He has published more than 70 research articles in peer-reviewed journals. His work includes but is not limited to phospholipid methylation, calcium traversal across bilayer, activators of protein kinase C, factors involved in the fibrillization of amyloid beta-protein, role of gelsolin in Alzheimer's disease, and membrane abnormalities and cellular signaling in autism.
 
Dr. Chauhan is the editor of the book Autism: Oxidative stress, Inflammation, and Immune Abnormalities and associate editor of the "Special Issue on Autism Spectrum Disorders" of the American Journal of Biochemistry and Biotechnology (2008). He is also a member of the editorial board of International Archives of Medicine and associate editor of the Journal of Alzheimer's.

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