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

描述（由申请人提供）：仅在美国，每年约有140万患者需要小口径（< 6 mm ID）冠状动脉或外周血管移植物。超过10%的患者没有合适的自体血管移植。然而，目前的合成假体，如膨胀型聚四氟乙烯（ePTFE）移植物，在小直径应用中显示出高故障率。因此，组织工程血管移植物（TEVG）正在积极开发用于小口径应用。尽管已经取得了显著的进展，但TEVG的临床生存能力受到以下因素的阻碍：1）由内皮化不足导致的血栓形成，2）频繁需要植入前细胞和/或构建体培养，3）移植物和宿主组织之间的短期和长期顺应性不匹配，以及4）由相关细胞的新基质沉积不足导致的长期机械强度不足。我们建议通过开发多层血管移植物（MLVG）来解决这些局限性，该多层血管移植物：1）允许立即形成用于短期和长期抗血栓形成的稳定的管腔细胞衬里，2）结合了专门设计用于将人脂肪来源的间充质干细胞（ASC）分别导向血管平滑肌细胞（VSMC）或内皮细胞（EC）命运的中间和管腔水凝胶层，3）将这些水凝胶与设计用于短期顺应性匹配的中心静电纺丝网相结合，和4）包括提供破裂强度、外膜细胞募集和血管向内生长的静电纺丝套管。拟定的研究将重点开发拟定的内侧和管腔水凝胶层。为此，我们将执行以下具体目标：AIM 1：鉴定诱导ASC分化为VSMC样表型和中层适当细胞外基质合成的载有生长因子的PEG水凝胶制剂。目的2：确定生长因子负载，PEG“水泥”配方，促进ASC分化成EC样表型。

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.