Abstract
Novel therapeutic angiogenic concepts for critical limb ischemia are still needed for limb salvage. E-selectin, a cell-adhesion molecule, is vital for recruitment of the stem/progenitor cells necessary for neovascularization in ischemic tissues. We hypothesized that priming ischemic limb tissue with E-selectin/adeno-associated virus (AAV) gene therapy, in a murine hindlimb ischemia and gangrene model, would increase therapeutic angiogenesis and improve gangrene.
FVB/NJ mice were given intramuscular hindlimb injections of either E-selectin/AAV or LacZ/AAV and then underwent induction of gangrene via femoral artery ligation and concomitant systemic injections of the nitric oxide synthesis inhibitor L-NAME (L-NG-Nitro arginine methyl ester; 40 mg/kg). Gangrene was evaluated via the Faber hindlimb appearance score. The rate of ischemic limb reperfusion and ischemic tissue angiogenesis were evaluated using laser Doppler perfusion imaging and DiI perfusion with confocal laser scanning microscopy of the ischemic footpads, respectively. The treadmill exhaustion test was performed on postoperative day (POD) 8 to determine hindlimb functionality.
The E-selectin/AAV–treated mice (n = 10) had decreased Faber ischemia scores compared with those of the LacZ/AAV–treated mice (n = 7) at both PODs 7 and 14 (P < .05 and P < .01, respectively), improved laser Doppler perfusion imaging reperfusion indexes by POD 14 (P < .01), and greater gangrene footpad capillary density (P < .001). E-selectin/AAV–treated mice also had improved exercise tolerance (P < .05) and lower relative muscular atrophy (P < .01).
We surmised that E-selectin/AAV gene therapy would significantly promote hindlimb angiogenesis, reperfusion, and limb functionality in mice with hindlimb ischemia and gangrene. Our findings highlight the reported novel gene therapy approach to critical limb ischemia as a potential therapeutic option for future clinical studies.
In the United States, >150,000 limb amputations are performed annually for critical limb ischemia (CLI) despite the use of medical and surgical therapy. Thus, novel therapeutic angiogenic concepts for CLI are still needed for limb salvage. We used a novel gene therapy approach in a mouse model of gangrene, the most severe form of CLI, to demonstrate the efficacy of our gene therapy with E-selectin. Preclinical studies such as ours are a vital step in the development of new therapies for CLI patients with threatened limbs and no further medical or surgical options.
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