Abstract 639: Carnosine Supplementation Promotes Revascularization in Mouse model of Hindlimb Ischemia

Abstract

Revascularization surgeries are important for treatment of critical limb ischemia (CLI) however, advanced CLI patients are poor candidates for these surgeries. Here, we proposed that carnosine, a dipeptide of β-alanine and histidine which is highly abundant in the skeletal muscle (2-20mM) and has the abilities to quench reactive aldehydes and chelate divalent metals, can promote revascularization. WTC57Bl/6 mice were pre-treated with carnosine (1g/L) in drinking water for 7 days, subjected to hindlimb ischemia surgery (HLI) by femoral artery ligation and allowed to recover for 14 days with carnosine supplementation. Doppler analysis showed that carnosine supplementation increased blood perfusion to 63±6% compared to 19±3% in controls. Post-surgery carnosine treatment also increased blood flow to 49.4± 6% compared to 28.2± 4% in controls following 21 days of recovery. Histological analysis of the ischemic limb showed that tissue injury was attenuated by carnosine supplementation. Mobilization of angiogenic endothelial progenitor cells (EPCs) (Flk+/Sca+) and the expression of vascular endothelial growth factor (VEGF) in the ischemic muscle was enhanced by carnosine treatment. These results were associated with an increase in ischemic muscle carnosine levels in the carnosine treated HLI mice. Furthermore, expression of the carnosine transporter PHT1 was increased in carnosine treated HLI mice compared to HLI mice. Concomitant with the increased VEGF expression in carnosine treated HLI mice, we observed that pre-treatment of murine myoblast C2C12 cells with octyl-D-carnosine followed by hypoxia increased hypoxia inducible factor 1-alpha nuclear translocation and VEGF expression and secretion. Our results demonstrate that carnosine treatment increases blood flow in the ischemic limb by increasing EPC mobilization and therefore can be a potential therapeutic intervention for CLI patients.