Abstract 15282: RGDS- Presenting Peptide Amphiphile Nanofibers Enhance Endothelial Progenitor Cell Therapy in Diabetic Mice With Critical Limb Ischemia
Critical limb ischemia (CLI) is estimated to affect approximately two million people. Up to 40% of these patients are not candidates for surgery and of those approximately 25% will require a major amputation. It is imperative to develop new therapies that enhance angiogenesis and minimize the impact of the blocked vessel(s). Endothelial progenitor cell (EPC) therapy has shown some promise, however, the cells may not remain at the site of injury long enough to significantly impact the course of the disease. Further, the underlying disease, such as diabetes, which resulted in CLI also negatively impacts the function of the EPCs. Our objective was to enhance cell therapy for CLI by using peptide amphiphile (PA) nanofibers displaying the fibronectin-derived RGDS cell adhesion epitope as a scaffold for therapeutic delivery of EPCs. First, we confirmed in vitro that EPCs from diabetic mice (db/db) exhibited enhanced survival on the RGDS PA when compared to a scrambled (DGRS) PA. Additionally, RNA for the pro-angiogenic proteins VEGF and ENOS were upregulated 3 days after plating db/db EPCs with RGDS PA as compared to cells plated on DGRS PA or tissue culture plastic. Conditioned media (CM) from db/db EPCs+ RGDS restored tubule formation of HUVECs in matrigel to levels observed from healthy EPC (db/+) CM, and significantly more than CM from Db/db EPCs plated on tissue culture plastic or DGSR PA (p<.05; n=3). Uni-lateral ischemia was induced by ligation of the femoral artery in db/db mice followed by injection of: (1) PBS (2) 100,000 db/db EPCs (3) scrambled PA + db/db EPCs (4) RGDS PA+ db/db EPCs. Four weeks post-injection, blood flow (measured by laser Doppler) and limb function were increased in the RGDS PA+ EPC group while necrosis was decreased compared to the other groups (n>8). Further, lectin+ cells (blood vessels), NCAM+ cells (satellite cells), and central nuclei (regenerating muscle) were increased in the Cells+RGDS group. Finally, a significant increase in VEGF (PCR) was found in the ischemic limb of the mice receiving cells+RGDS when compared to the other groups. Taken together, these results suggest RGDS PA+ db/db EPCs enhances recovery from CLI in diabetic mice by enhancing angiogenesis.
- © 2013 by American Heart Association, Inc.