[Oxidative stress in human diseases]

Oxidative stress is an abnormal phenomenon occurring inside our cells or tissues when production of oxygen radicals exceeds their antioxidant capacity. Excess of free radicals damage essential macromolecules of the cell, leading to abnormal gene expression, disturbance in receptor activity, proliferation or cell dye, immunity perturbation, mutagenesis, protein or lipofushin deposition. Numerous human diseases involve during the pathological process such a stress, localized or general (in the same way as inflammation). In many serious diseases such as cancer, ocular degeneration (age related macular degeneration or cataract), neurodegenerative diseases (ataxia, amyotrophic lateral sclerosis, Alzheimer's disease) stress is the factor original. In familial amyotrophic lateral sclerosis the genetic abnormality occurred an abnormal coding for an antioxidant enzyme, copper-zinc super oxide dismutase. In various other diseases oxidative stress occur secondary to the initial disease but plays an important in role immune or vascular complications. This is the case in infectious disease such as AIDS or septic shock, Parkinson's disease or renal failure. So antioxidant treatment seems logical to be tested in these pathologies. But they have to be applied early in the process, before irreversible mechanisms. They need also to be prescribed at low doses as baseline free radical production have to be preserved to maintain useful activity that cannot be suppressed.