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Isolation and Differentiation of Porcine Progenitor Cells into Endothelial-like Cells for Vascular Tissue Engineering

Josephine B. Allen1, Sadiya Khan1, Delara Motlagh1, María Concepción-Serrano2, Asha Shekaran1, and Guillermo A. Ameer1. (1) Biomedical Engineering Department, Northwestern University, 2145 Sheridan Road, E310, Evanston, IL 60208, (2) Department of Biochemistry and Molecular Biology I, Universidad Complutense, Faculty of Chemistry, Madrid, 28040, Spain

As the number of people with cardiovascular disease increases, so does the need for vascular grafts to replace diseased or damaged small-diameter blood vessels. The current standard-of-care can not adequately address this problem, prompting researchers to use tissue engineering techniques to create new small diameter blood vessels. However, identifying a suitable cell source and polymer scaffold that can be used to fully re-create the properties of a native blood vessel continues to be a challenge. One potential cell source is endothelial progenitor cells (EPC), which are found in peripheral blood and can be differentiated into endothelial-like cells [1]. In this work, we assess the feasibility of using EPCs to generate a functional endothelium on poly(1,8-octanediol-co-citrate) (POC), a biodegradable elastomeric polyester for potential use in vascular tissue engineering [2]. EPCs were isolated from porcine blood and biochemically differentiated into porcine endothelial-like cells (PE-like) in vitro. Once differentiated, the endothelial phenotype and function was confirmed by: a) the characteristic cobblestone morphology of cultured endothelial cells, b) positive staining for endothelial cell-specific markers von Willebrand factor and VE-cadherin, c) metabolism of acetylated low density lipoprotein, d) production and secretion of anti-thrombogenic factors nitric oxide and prostaglandin, e) inhibition of platelet adhesion in vitro, and f) inhibition of clotting processes, resulting in decreased rate of clot formation in vitro. Additionally, the PE-like cells had decreased expression of the highly immunogenic antigen Gal[alpha]1-3Gal[beta]1-4GlcNac-R (α-Gal), which contributes to hyperacute rejection of porcine tissues by human recipients. Collectively, these data suggest that POC seeded with PE-like cells could potentially have a major impact on vascular tissue engineering, perhaps providing a suitable autologous vascular graft for in vivo animal studies and/or as a potential xenogenic cell source for human vascular tissue engineering applications.

1. Khakoo AY, Finkel T. Endothelial progenitor cells. Annu Rev Med. 2005; 56:79-101.

2. Yang J, Motlagh D, Webb AR, Ameer GA. Novel biphasic elastomeric scaffold for small-diameter blood vessel tissue engineering. Tissue Eng. 2005 Nov-Dec;11(11-12):1876-86.