P129	Identification and characterization of activated aortic valve cells with high angiogenic potential.
1F.Chalajour, 1H.Treede, 2U.M.Gehling, 3A.Ebrahimnejad, 1D.H.Boehm, 4S.Ergün, 1H.Reichenspurner, on behalf of University Heart Center Research Group
1Department of Cardiovascular Surgery, University Heart Center, Hamburg-Eppendorf, Hamburg, DE; 2Department of Hepatobiliary Surgery and Visceral Transplantation, University Hospital Eppendorf, Hamburg, DE; 3Department of Clinical Chemistry, University Hospital Eppendorf, Hamburg, DE; 4Department of Anatomy, University Hospital Eppendorf, Hamburg, DE.

Revascularization of ischemic tissues using organ-specific vessels is the main aim and ideal way for therapy of ischemic disease. Recent data revealed formation of angiogenic sprouts from calcific aortic valve (CAV) explants and proved the ability of primary cells derived from these structures to generate blood vessels in a static system. In this study, we evaluated the cellular components of angiogenic sprouts from CAV before culturing in collagen matrix and found that smooth muscle α-actin expressing (α-SMA+) cells which were positive (+) for Tie-2 and vascular endothelial growth factor receptor-2 (KDR/VEGFR-2) play a pivotal role in the initiation of sprout formation. Endothelization of angiogenic sprouts was detected within elongated outgrowths by positive staining for the endothelial cell (EC) marker CD34. The observation that the majority of cells isolated from cultures of CAV contained α-SMA+, Tie-2+, and KDR+ cells further confirmed our findings. A low percentage of cells isolated from angiogenic sprouts expressed EC markers CD31, CD34, and CD105 but not the endothelial progenitor marker CD133. In contrast to cells isolated from culture of non-calcific valves, the angiogenic activity of cells isolated from culture of CAV was increased as demonstrated in migration and tube assays. Furthermore, these cells spontaneously formed vessels-like structure on a collagen-based matrix by a self-organization mechanism. These data suggest that cells isolated from angiogenic sprouts can be used for engineering of organ-specific vessels and may help to develop a vascular supply for tissue engineering of whole organs.

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