Lipoxins and novel 15-epi-lipoxin analogs display potent anti-inflammatory actions after oral administration

1 Lipoxins (LX) and aspirin-triggered 15-epi-lipoxins (ATL) exert potent anti-inflammatory actions. In the present study, we determined the anti-inflammatory efficacy of endogenous LXA(4) and LXB4, the stable ATL analog ATLa2, and a series of novel 3-oxa-ATL analogs (ZK-996, ZK-990, ZK-994, and ZK-142) after intravenous, oral, and topical administration in mice. 2 LXA(4), LXB4, ATLa2, and ZK-994 were orally active, exhibiting potent systemic inhibition of zymosan A-induced peritonitis at very low doses (50 ng kg(-1) - 50 mug kg(-1)). 3 Intravenous ZK-994 and ZK-142 (500 mug kg(-1)) potently attenuated hind limb ischemia/ reperfusion-induced lung injury, with 32 +/- 12 and 53 +/- 5% inhibition ( P<0.05), respectively, of neutrophil accumulation in lungs. The same dose of ATLa2 had no significant protective action. 4 Topical application of ATLa2, ZK-994, and ZK-142 (similar to 20 mu g cm(-2)) prevented vascular leakage and neutrophil infiltration in LTB4/PGE(2)-stimulated ear skin inflammation. While ATLa2 and ZK-142 displayed approximately equal anti-inflammatory efficacy in this model, ZK-994 displayed a slower onset of action. 5 In summary, native LXA(4) and LXB4, and analogs ATLa2, ZK-142, and ZK-994 retain broad antiinflammatory effects after intravenous, oral, and topical administration. The 3-oxa-ATL analogs, which have enhanced metabolic and chemical stability and a superior pharmacokinetic profile, provide new opportunities to explore the actions and therapeutic potential for LX and ATL.