Oxidative stress: an accomplice to uremic toxicity?

Oxidative processes are inherent to life. Basic requirements such as energy production and defending the self imply free radical generation, exposing both sides of cell membranes to their potential toxic actions. Initially, the term oxidative stress was coined to describe mostly the biochemical imbalance between the generation of oxidants and the antioxidant defense. In contrast, the current definition underlines the importance of tissue damage resulting from the imbalance between an excessive generation of oxidant compounds and antioxidant defense mechanisms. Although more and more sophisticated markers of oxidative stress were described, there are relatively few studies investigating the relationships among these markers and outcome. The review of these studies suggests that oxidative stress, inflammation, and malnutrition are in various proportions strong predictors of outcome, especially from a cardiovascular point of view, in chronic kidney disease patients. The precise contribution of each factor is difficult to ascertain for the moment, but oxidative stress could safely be added to inflammation and malnutrition as an accomplice to uremic toxicity. The "immune connection" seems to offer a new explanation for the association between oxidative stress, inflammation, and outcome in chronic kidney disease patients.