Lipoxin B4 (LXB4)

Lipoxins are a series of anti-inflammatory mediators. Lipoxins are short lived endogenously produced nonclassic eicosanoids whose appearance in inflammation signals the resolution of inflammation. They are abbreviated as LX, an acronym for lipoxygenase (LO) interaction products. At present two lipoxins have been identified; lipoxin A4 (LXA4) and lipoxin B4 (LXB4). Similarly to the leukotrienes, LXA4 will form the cysteinyl-lipoxins LXC4, LXD4 and LXE4. At subnanomolar concentrations, LXA4 and LXB4 inhibit leukotriene-stimulated interactions of human neutrophils and endothelial cells.Lipoxins are high affinity antagonists to the cysteinyl leukotriene receptor type 1 to which several leukotrienes (LTC4, LTD4 and LTE4) mediate their smooth muscle contraction and eosinophil chemotactic effects.