Generating Vascular Graft Luminal and Medial Layers Based on Multipotent Stem Cel

Rensselaer Polytechnic Institute, Troy NY

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Abstract

DESCRIPTION (provided by applicant): In the US alone, approximately 1.4 million patients require small-caliber (< 6 mm ID) coronary artery or peripheral vessel grafts each year. Over 10% of these patients have no suitable autologous vessels for grafting. However, current synthetic prostheses, such as expanded polytetrafluoroethylene (ePTFE) grafts, display high failure rates in small-diameter applications. Tissue engineered vascular grafts (TEVGs) are therefore being actively developed for small-caliber applications. Although significant progress has been made, TEVG clinical viability has been hampered by: 1) thrombogenicity resulting from inadequate endothelialization, 2) the frequent need for pre-implantation cell and/or construct culture, 3) short- and long-term compliance mismatch between graft and host tissue, and 4) inadequate long-term mechanical strength resulting from insufficient neomatrix deposition by associated cells. We propose to address these limitations by developing a multilayered vascular graft (MLVG) which: 1) allows immediate formation of a stable, luminal cell lining for short- and long-term thromboresistance, 2) incorporates medial and luminal hydrogel layers specifically designed to direct human adipose-derived mesenchymal stem cells (ASCs) toward vascular smooth muscle cell (VSMC) or endothelial cell (EC) fates, respectively, 3) combines these hydrogels with a central electrospun mesh designed for short-term compliance-matching, and 4) includes an electrospun sleeve providing for burst strength, adventitial cell recruitment, and vaso vasorum ingrowth. The proposed studies will focus on developing the proposed medial and luminal hydrogel layers. Towards this end, we will execute the following Specific Aims: AIM 1: Identify growth-factor laden, PEG hydrogel formulations inductive of ASC differentiation into VSMC-like phenotypes and medial layer-appropriate extracellular matrix synthesis. AIM 2: Identify growth factor-laden, PEG cement formulations that promote ASC differentiation into EC-like phenotypes.