Role of free radicals in septic shock

The available data supporting the role of oxygen radicals (OR0) as fundamental--though not unique--mediators in the pathogenesis of sepsis and septic shock are reviewed. The main questions are 1) Are there any signs of OR0 overgeneration during sepsis and septic shock? 2) Are there any indirect signs of OR0 damage during sepsis and septic shock? 3) Does OR0 inactivation affect the evolution and severity of sepsis and septic shock? 4) May the pathophysiology of sepsis and septic shock be viewed as a consequence of OR0 overgeneration? All these questions might receive affirmative answers; thus the relationships of OR0 with other mediators of sepsis and septic shock are discussed. It emerges that all the molecules which are being considered as mediators of sepsis and septic shock (cytokines, endothelins, platelet activating factor, complement) may act on granulocytes and other phagocytic cells to stimulate OR0 production. There are also very close relationships with nitric oxide, another free radical. The data in favour of an antioxidant therapy of sepsis and septic shock in humans are too few to be conclusive.