The role of aspirin-triggered lipoxins in the mechanism of action of aspirin.

Few drugs have treated so many diseases, provided us with so much understanding of their pathogenesis, and tested our scientific creativity over the last 100 years as much as aspirin. Originally, the beneficial effects of aspirin were shown to stem from its inhibition of cyclooxygenase (COX 2)-derived prostanoids, fatty acid metabolites that modulate host defense and regulate the cardiovascular system. However, the inhibition of COX 2 enzyme activity and prostaglandin synthesis has never fully explained aspirin's repertoire of anti-inflammatory effects, leaving many questions pertaining to its true mechanism of action unanswered. Here, data from a series of comparatively recent experiments exploring aspirin's unique ability to acetylate the active site of inducible COX 2 and generate a family of lipid mediators called the epi-Lipoxins will be discussed in light of their ability to exert profound modulatory effects on the innate and adaptive immune systems.