Abstract 13786: Functional Enhancement of Circulating Angiogenic Cells Cultured on a Collagen Biomaterial Using the Cysteine-rich Angiogenic Inducer 61 (CYR-61) Protein
BACKGROUND: Therapy with circulating angiogenic cells (CACs) has the ability to promote neovascularization of ischemic tissue. We have previously demonstrated that the culture of CACs on a collagen biomaterial significantly enhances their regenerative potential; however, further improvements are needed. We aimed to address this by incorporating cysteine-rich angiogenic inducer 61 (CYR-61), a secreted ECM associated protein, into the collagen biomaterial.
METHODS/RESULTS: Recombinant CYR-61 was incorporated into a collagen type I based matrix using EDC/NHS cross-linking. This CYR-61-matrix increased CAC adhesion by 2.2±1.0 fold vs. unloaded matrix (p=0.03) and 4.8±2.4 fold vs. fibronectin (p=0.02). Furthermore, the number of adherent proangiogenic CD34+ and CD133+ progenitor cells on CYR-61-matrix was increased 3.3±1.1 and 2.7±0.4 fold, respectively, vs. unloaded matrix (p<0.05). In a HUVEC/CAC angiogenesis assay, CACs treated with the CYR-61 demonstrated a 4.1±1.6 and 7.3±1.4 fold increase in cell incorporation into capillary-like structures compared to matrix (p=0.03) and fibronectin (p=0.02) cultured CACs, respectively. The total tubule network formed was also greater by 5.1±0.6 fold (p=0.007) for CYR-61-treated CACs compared to matrix-cultured cells. Using CYR-61 as a chemoattractant, CAC migration was increased 5.0±2.1 fold compared to CYR-61-free control media (p=0.04). Specifically blocking integrin αV, a target for CYR-61,reduced CAC adhesion by 52% and migration by 78% (p<0.05). In vivo, intramuscular injection of matrix-cultured CACs treated with CYR-61 resulted in an 80±1.8% blood flow recovery in ischemic mouse hindlimbs, while untreated CACs and PBS treatments displayed 66±1.6% and 35.5±2.3% recovery, respectively (p≤0.02).
CONCLUSIONS: We demonstrate that the function of CACs is enhanced when CYR-61 is added to our collagen matrix. The cells have increased in adhesion, angiogenic capability and ability to restore blood flow to ischemic tissue. Furthermore, we demonstrate that CYR-61 has the ability to act as a chemotactic factor, which may serve to recruit host CACs to the site of delivery. These findings demonstrate a novel mechanism which may be used to further promote tissue neovascularization.
- © 2013 by American Heart Association, Inc.