Fibrinogen &ggr;-Chain Peptide–Coated Adenosine 5' Diphosphate–Encapsulated Liposomes Rescue Mice From Lethal Blast Lung Injury via Adenosine Signaling*

Objectives: Fibrinogen &ggr;-chain (dodecapeptide HHLGGAKQAGDV)-coated adenosine 5′-diphosphate–encapsulated liposomes can accumulate via dodecapeptide HHLGGAKQAGDV interactions at bleeding sites where they release adenosine 5′-diphosphate that is rapidly metabolized to adenosine, which has tissue-protective effects. We investigated the efficacy of fibrinogen &ggr;-chain (dodecapeptide HHLGGAKQAGDV)-coated adenosine 5′-diphosphate–encapsulated liposomes to treat blast lung injury, with a focus on adenosine signaling. Design: Controlled animal study. Setting: University research laboratory. Subjects: Adult male C57BL/6 mice. Interventions: Mice were pretreated with fibrinogen &ggr;-chain (dodecapeptide HHLGGAKQAGDV)-coated adenosine 5′-diphosphate–encapsulated liposomes, dodecapeptide HHLGGAKQAGDV-(phosphate-buffered saline)-liposomes, adenosine 5' diphosphateliposomes, or phosphate-buffered saline-liposomes. Five minutes after treatment the mice received a single laser-induced shock wave (1.8 J/cm2) that caused lethal blast lung injury, and their survival times and lung injuries were then assessed. We also evaluated the therapeutic effect of posttreatment with fibrinogen &ggr;-chain (dodecapeptide HHLGGAKQAGDV)-coated adenosine 5′-diphosphate–encapsulated liposomes or H12-(phosphate-buffered saline)-liposomes 1 minute after laser-induced shock wave exposure. To examine the effect of adenosine signaling, adenosine A2A receptor (ZM241385) or adenosine A2B receptor (PSB 1115) antagonists were administered to the mice 1 hour before the pretreatment with fibrinogen &ggr;-chain (dodecapeptide HHLGGAKQAGDV)-coated adenosine 5′-diphosphate–encapsulated liposomes that was followed by laser-induced shock wave exposure. Measurements and Main Results: Pre- and posttreatment with fibrinogen &ggr;-chain (dodecapeptide HHLGGAKQAGDV)-coated adenosine 5′-diphosphate–encapsulated liposomes significantly increased mouse survival [fibrinogen &ggr;-chain (dodecapeptide HHLGGAKQAGDV)-coated adenosine 5′-diphosphate–encapsulated liposomes: 58% survival vs H12-(phosphate-buffered saline)-liposomes: 8%; p < 0.05 (posttreatment)] and mitigated pulmonary tissue damage/hemorrhage and neutrophil accumulation after laser-induced shock wave exposure. fibrinogen &ggr;-chain (dodecapeptide HHLGGAKQAGDV)-coated adenosine 5′-diphosphate–encapsulated liposomes accumulated at pulmonary vessel injury sites after laser-induced shock wave exposure with both pre- and posttreatment. Furthermore, pretreatment with fibrinogen &ggr;-chain (dodecapeptide HHLGGAKQAGDV)-coated adenosine 5′-diphosphate–encapsulated liposomes reduced albumin and macrophage inflammatory protein-2 levels in bronchoalveolar lavage fluid. Although fibrinogen &ggr;-chain (dodecapeptide HHLGGAKQAGDV)-coated adenosine 5′-diphosphate–encapsulated liposomes pretreatment did not affect blood coagulation activity in the injured mice, its beneficial effect on blast lung injury was significantly abrogated by A2A or A2B adenosine receptor antagonists (A2A antagonist: 17% survival; A2B antagonist: 33% vs dimethyl sulfoxide control: 80%; p < 0.05, respectively). Conclusions: Fibrinogen &ggr;-chain (dodecapeptide HHLGGAKQA GDV)-coated adenosine 5′-diphosphate–encapsulated liposomes may be effective against blast lung injury by promoting tissue-protective adenosine signaling and could represent a novel controlled-release drug delivery system.