Abstract 44: Tissue-Protective Effects of an Erythropoietin Derivative in in vitro and in vivo Models of Skeletal Muscle Ischemia

Abstract

Introduction: A third of patients with critical limb ischemia (CLI) eventually require amputation. In spite of clinically successful revascularization patients rarely return to their pre-morbid status, and often fail to notice an improvement in their functional outcomes, which may be due to an underlying musculopathy. Non-hematopoietic EPO-derivatives have been designed to retain only tissue-protective functions of EPO. We hypothesized that ARA-290 (EPO-derivative) may have tissue-protective potential that would represent a novel therapeutic adjunct in patients with CLI. Methods: The effect of ARA-290 in mediating cytoprotection was assessed firstly in vitro using skeletal myoblasts isolated from CLI and control donors, and a model of simulated ischemia. Characterization of CLI myoblasts was also performed, to asses their contractile, migratory and proliferative ability. Subsequently, an in vivo murine model of hindlimb ischemia, which recapitulates the muscular pathology observed in CLI patients, was used to assess the potential of ARA-290 to improve functional, histological and perfusion outcomes. Results: Skeletal myoblasts were successfully isolated from CLI patients for the first time. CLI myoblasts and myotubes exhibited increased proliferative capacity but reduced migratory and contractile function and importantly a reduced susceptibility to a second ischemic-insult compared with control myoblasts and myotubes. ARA-290 treatment led to significant improvements in both CLI and Control myoblasts and myotube function and survival via the JAK2/STAT3, PI3k/Akt and NFκB signalling pathways. In vivo, animals treated with ARA-290 demonstrated improved functional, histological and perfusion outcomes compared to vehicle-control treated animals. Conclusion: These studies demonstrate the potential of ARA-290 to protect tissues and cells from ischemic-injury and encourages the development of novel pharmacological therapies for use in patients with “no option” CLI or severe functional deficit.