P79	Stimulation of reendothelialization via recruitment of endothelial progenitor cells with selective antibodies against progenitor cell surface markers.
E.Dernbach, C.Urbich
Molecular Cardiology, University Frankfurt/Main, Frankfurt/Main, DE.

The inact endothelium controls diverse processes like vascular tone and homeostasis. Denudation of the Endothelium by percutaneous coronary intervention contributes to increased neointima formation. Recruitment and adhesion of circulating endothelial progenitor cells (EPCs) was shown to contribute to reendothelialization and to reduce neointima formation. EPCs can be differentiated out of the peripheral blood or circulating CD34+ and CD133+ progenitor cells. Therefore, we investigated whether coating of cell culture dishes with selective capturing antibodies against progenitor cell surface markers (CD34, CD105, CD133) enhances the adhesion and differentiation of EPCs. Coating of culture dishes with capturing antibodies significantly enhanced the adhesion of blood-derived mononuclear cells (MNCs) under static conditions (CD34: 460±96%; CD105: 174±3%; CD133: 959±87% of non-coated control; p<0.05). For therapeutical approach, cells must adhere under physiological flow conditions. Therefore we also examined the adhesion of MNCs under laminar flow in a cone and plate apparatus. Although the absolute adhesion rate was lower during physiological flow conditions as compared to static conditions, cell adhesion was profoundly increased by 3-4-fold in culture dishes coated with antibodies against CD34, CD105 and CD133 compared to non-coated culture dishes (CD34: 346±20%; CD105: 304±16%; CD133: 284±24% of non-coated control; p<0.05). Moreover, we further investigated whether shear stress induces the differentiation of antibody captured MNCs. Indeed, in capturing antibody coated dishes, shear stress significantly increased expression of the corresponding progenitor cell surface marker, but decreased expression of the monocytic marker CD14 of MNCs as measured by FACS analysis (static set as 100%; CD34-coated: CD34: 209±53%, CD14: 58±12%; CD105-coated: CD105: 296±172%, CD14: 64±4%; CD133-coated: CD133: 394±179%, CD14: 65±10% of static control). Conclusion: Coating with capturing antibodies against progenitor cell surface markers profoundly enhances not only adhesion of EPCs, but also stimulates the flow-mediated differentiation towards an endothelial progenitor cell phenotype. Enhanced recruitment of EPCs by local application of capturing progenitor cell antibodies may accelerate reendothelialization and, thus, limit neointima formation folllowing endothelial denudation.

Copyright © 2005 S. Karger AG, Basel. Any further use of this abstract requires written permission from the publisher.