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.