Leukotrienes and Lipoxins

Publisher Summary This chapter reviews the biology of the leukotrienes (LTB4, LTC4, LTD4, and LTE4) and lipoxins (LXA4 and LXB4), which are molecules derived by lipoxygenation of arachidonic acid. It explores the role of leukotrienes and lipoxins in bronchial asthma and chronic obstructive pulmonary disease (COPD). They are produced by constitutive cells, like mast cells/ macrophages) and infiltrating cells (eosinophils, neutrophils) implicated in asthma and COPD. Laboratory-induced asthma and spontaneous asthma or COPD is associated with an enhanced recovery of leukotrienes in the urine and exhaled breath condensate of subjects with asthma and sputum, BAL or exhaled breath condensate leukotrienes in COPD. They are potent bronchoconstrictor agonists. Their administration results in the expression of mucus from mucous glands. Agents capable of interfering with leukotriene action or synthesis enhance asthma control. Similar data are not available for COPD. The data indicate that the leukotrienes play an important role in the asthmatic response. But the importance of the pathogenetic role of the leukotrienes in COPD is still not known. Lipoxins are generated in respiratory tissues in asthma and COPD and can decrease airway inflammation and hyperresponsiveness in laboratory-induced asthma. Since these data are not biologically informative with respect to the role the leukotrienes in COPD, larger better-controlled studies are needed to resolve this issue.