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Introduction: Peripheral vascular disease (PVD) is a major cause of morbidity in the US. Vascular endothelial growth factor (VEGF) induces angiogenesis through Fetal-Liver Kinase-1 (Flk-1 or VEGFR-2), an endothelial tyrosine… Click to show full abstract
Introduction: Peripheral vascular disease (PVD) is a major cause of morbidity in the US. Vascular endothelial growth factor (VEGF) induces angiogenesis through Fetal-Liver Kinase-1 (Flk-1 or VEGFR-2), an endothelial tyrosine kinase receptor which activates a downstream signaling cascade involving MAPKAPKinase2 (MK2). We have demonstrated poorer recovery in hind limb ischemia models using Flk-1 +/- and MK2 -/- knockout mice compared to wild type mice. We also demonstrated overespression of Pellino1 (Peli1), an E3 Ligase, can attenuate ischemic damage and increase neovascularization and survivability of ischemic myocardium and skin flaps. Therefore, in this study we aim to show if Peli1 gene therapy can help rescue function in Flk-1 +/- and MK2 -/- after femoral artery ligation. Methods: 8-12 week-old Flk-1 +/- and MK2 -/- mice were subjected to femoral artery ligation of the right hind limb and treated with either adenovirus carrying Peli1 (Ad.Peli1) or LacZ (Ad.LacZ), for a total of 4 groups: Flk-1 +/- Ad.LacZ, Flk-1 +/- Ad.Peli1, MK2 -/- Ad.LacZ and MK2 -/- Ad.Peli1. Perfusion was assessed with laser Doppler imaging preop and on days 0, 3, 7, 14, 21 and 28. Extent of limb ischemia was also quantified using a standardized scoring scale (0 = no ischemia, to 8 = full limb amputation). Results: Perfusion was significantly higher in the Flk-1 +/- Ad.Peli1 group compared to Flk-1 +/- Ad.LacZ on days 7 (0.19±0.03 vs 0.08±0.02), 14 (0.41±0.07 vs 0.09±0.03), 21 (0.33±0.05 vs 0.14±0.05) and 28 (0.31±0.05 vs 0.15±0.02) (n=9-15, p<0.05). The level of ischemia (ischemic score) was significantly lower in the Flk-1 +/- Ad.Peli1 group when compared to Flk-1 +/- Ad.LacZ on days 3 (1.89±0.56 vs 4.88±0.85), 7 (2.11±0.54 vs 5.69±0.92), 14 (2.18±0.52 vs 6.31±1.02), 21 (1.83±0.58 vs 6.50±1.05) and 28 (1.67±0.62 vs 6.50±1.05) (n=8-9, p<0.05). There was no difference in perfusion or ischemic score between the MK2 -/- Ad.Peli1 and MK2 -/- Ad.LacZ groups. Values are mean +/- SEM. Conclusions: Treatment with Ad.Peli1 resulted in improved perfusion and decreased tissue ischemia in Flk-1 +/- mice. These results were not paralleled in MK2 -/- mice suggesting that Peli1 acts upstream to MK2 but downstream of VEGF/Flk-1. Overall, Peli1 gene therapy is a promising candidate in the management of PVD.