Background: Revascularization of amputated extremities after prolonged ischemia is complicated by reperfusion injury. We assessed ischemia/reperfusion (I/R) injury of porcine extremities after prolonged preservation using extracorporeal circulation (ECC).
Methods: Forelimbs of 32 pigs were divided into four groups based on ischemia times: group I: 6 h, group II: 12 h, group III: 0 h plus replantation, and group IV: 6 h plus replantation. Limbs were perfused with autologous blood using ECC for 12 h except group II with only 5 h perfusion. Limbs from groups III and IV were heterotopically replanted with a 7-d follow-up. Contralateral limbs served as controls in all groups. Tissue, plasma, and serum were analyzed for the extent of I/R injury.
Results: No significant differences in tissue wet/dry ratios were found within or between groups. This finding was confirmed by histology, except for an increased damage in group IV muscles compared with baseline (P = 0.016). Complement C3 deposition was only increased in group IV muscle (P = 0.031), group II nerves (P = 0.046), and group II vessels (P = 0.037). Group IV muscle and nerve tissues were the only ones with significant IgM antibody deposition (P = 0.031) at end of perfusion. Values were normal again after replantation. Reduced complement activity and elevated IL-6, IL-8, MCP-1, VEGF, PDGF-bb, bFGF, and complement split products were found during perfusion but were normal again after replantation. Staining for heparin sulfate proteoglycans and von Willebrand factor confirmed minimal activation of endothelial cells.
Conclusion: The results demonstrate that prolonged limb preservation using ECC has minimal impact on I/R-induced tissue injury. Extracorporeal perfusion is a potential limb-preserving technique encouraging further studies for use in limb revascularization.
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