Oxidative and Nitrosative Stresses: Their Role in Health and Disease in Man and Birds

The concept of oxidative stress (OS) was originally used by Professor Helmut Sies who described it as “an imbalance between oxidants and antioxidants in favor of the oxidants, potentially leading to damage” with the ratio of oxidants to antioxidants as >1 (Sies, 1997). Oxidative/nitrosative stress represents the bodies’ imbalance in the production and the elimination of reactive oxygen and nitrogen species and various reducing or antioxidant chemical systems of the body which destroy reactive intermediates and prevent/or repair the resultant damage. This is a particularly useful concept to establish a common basis for the longevity of a particular species as well as the many different disease states. However, it has also been found to be involved in a variety of other processes including immune protection of the body, gene control, growth as well as cell death. A parallel process is nitrosative stress (NS) which is defined as the ratio of nitrosants to antioxidants as >1 similarly to oxidative stress, but with involvement of reactive nitrogen species. This is a similar process that is involved with a variety of oxygen-nitrogen species causing excessive oxidation and/or nitrosylation compared to antioxidation or reduction. The question thus arises “What endogenous and exogenous strategies are available to cope with the damage associated with chronic oxidative and nitrosative stress?” It is the recombination of short lived radicals forming new strong oxidants which mainly cause the majority of the driving force for damage in oxidative and nitrosative stresses. Consequences of these particular inflammatory stresses are discussed as are endogenous and exogenous strategies to cope with this burden. Future research in antioxidant/repair therapy will result in the more effective treatment of diseases but it is better used as a preventative strategy. Limitations to the effective management of inflammatory stress are numerous and include the nature of the oxidants generated in association with the form and half-life of the particular antioxidant administered.