Double-chimera proteins to enhance recruitment of endothelial cells and their progenitor cells
ABSTRACT BACKGROUND: Enhanced attraction of selective vascular reparative cells is of great importance in order to increase vascular patency after endovascular treatments. We aimed to evaluate efficient attachment of endothelial cells and their progenitors on surfaces coated with mixture of specific antibodies, L-selectin and VE-cadherin, with prohibited platelet attachment. METHODS: The most efficient conditions for coating of L-selectin-Fc chimera and VE-cadherin-Fc chimera proteins were first determined by protein coating on ELISA plates. The whole processes were repeated on titanium substrates, which are commonly used to coat stents. Endothelial progenitor cells (EPCs) and human umbilical vein endothelial cells (HUVECs) were isolated and characterized by flow cytometry. Cell attachment, growth, proliferation, viability and surface cytotoxicity were evaluated using nuclear staining and MTT assay. Platelet and cell attachment were evaluated using scanning electron microscopy. RESULTS: Optimal concentration of each protein for surface coating was 50ng/ml. The efficacy of protein coating was both heat and pH independent. Calcium ions had significant impact on simultaneous dual-protein coating (P<0.05). Coating stability data revealed more than one year stability for these coated proteins at 4°C. L-selectin and VE-cadherin (ratio of 50:50) coated surface showed highest EPC and HUVEC attachment, viability and proliferation compared to single protein coated and non-coated titanium surfaces (P<0.05). This double coated surface did not show any cytotoxic effect. CONCLUSIONS: Surfaces coated with L-selectin and VE-cadherin are friendly surface for EPC and endothelial cell attachment with less platelet attachment. These desirable factors make the L-selectin and VE-cadherin coated surfaces perfect candidate endovascular device.
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ABSTRACT: Endothelial progenitor cell (EPC) capturing techniques have led to revolutionary strategies that can improve the performance of cardiovascular implant devices and engineered tissues by enhancing re-endothelialization and angiogenesis. However, these strategies are limited by controversies regarding the phenotypic identities of EPCs as well as their inability to target and prevent the other afflictions associated with current therapies, namely thrombosis and neointimal hyperplasia. Therefore, the goal of this study is to study the efficacy of a bioinspired multifunctional nanomatrix in recruiting and promoting the differentiation of EPCs towards an endothelial lineage. The bioinspired nanomatrix combines multiple components including self-assembled peptide amphiphiles (PAs) that include cell adhesive ligands, nitric oxide (NO) producing donors, and enzyme mediated degradable sequences to achieve an endothelium mimicking character. In this study, human peripheral blood mononuclear cells (PBMNCs) were isolated and cultured on the bioinspired multifunctional nanomatrix. Initial cell adhesion, lectin staining, Ac-LDL uptake, and expression of endothelial markers including CD31, CD34, vWF, and VEGFR2 were analyzed. The results from this study indicate that the NO releasing bioinspired multifunctional nanomatrix promotes initial adhesion of EPCs when compared to control surfaces. The expression of endothelial markers is also increased on the bioinspired multifunctional nanomatrix, suggesting that it directs the differentiation of EPCs towards an endothelial phenotype. The bioinspired nanomatrix therefore provides a novel biomaterial based platform for capturing as well as directing EPC behavior. Therefore this study has the potential to positively impact the patency of cardiovascular devices such as stents and vascular grafts as well as enhanced angiogenesis for ischemic or engineered tissues.Tissue Engineering Part C Methods 11/2012; 19(5). DOI:10.1089/ten.TEC.2012.0312 · 4.64 Impact Factor
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ABSTRACT: Due to the lack of success in small-diameter (<6mm) prosthetic vascular grafts, a variety of strategies have evolved utilizing a tissue engineering approach. Much of this work has focused on enhancing the endothelialization of these grafts. A healthy, confluent endothelial layer provides dynamic control over hemodynamics, influencing and preventing thrombosis and smooth-muscle cell proliferation that can lead to intimal hyperplasia. Strategies to improve endothelialization of biodegradable polymeric grafts have encompassed both chemical and physical modifications to graft surfaces, many focusing on the recruitment of endothelial and endothelial progenitor cells. This review aims to provide a compilation of current and developing strategies that utilize in situ endothelialization to improve vascular graft outcomes, providing a context for the future directions of vascular tissue engineering strategies that do not require preprocedural cell seeding.Tissue Engineering Part B Reviews 12/2012; 19(4). DOI:10.1089/ten.TEB.2012.0577 · 4.64 Impact Factor