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(&lt；6 mm ID)冠状动脉或外周血管移植。超过10%的患者没有合适的自体血管供移植。然而，目前的合成假体，如膨化聚四氟乙烯(EPTFE)移植物，在小直径应用中显示出高失败率。因此，组织工程血管移植物(TEVGs)正被积极开发用于小口径应用。虽然已经取得了显著的进展，但TEVG的临床生存受到以下因素的阻碍：1)内皮化不足导致的血栓形成；2)植入前细胞和/或构建培养的频繁需要；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)相关细胞沉积不足导致的长期机械强度不足。我们建议通过开发一种多层血管移植(MLVG)来解决这些限制，该材料：1)允许立即形成稳定的管腔细胞衬里，用于短期和长期的血栓抵抗；2)结合内侧和管腔水凝胶层，这些水凝胶层专门用于将人脂肪来源的间充质干细胞(ASCs)分别定向向血管平滑肌细胞(VSMC)或内皮细胞(EC)的命运；3)将这些水凝胶与为短期顺应性匹配而设计的中央电纺网结合；以及4)包括提供爆裂强度、外膜细胞招募和血管内长入的电纺袖套。拟议的研究将集中于开发拟议的内侧和管腔水凝胶层。为此，我们将实现以下具体目标：目标1：鉴定富含生长因子的聚乙二醇水凝胶制剂，诱导ASC分化为VSMC样表型和中层合适的细胞外基质合成。目标2：鉴定可促进ASC分化为EC样表型的携带生长因子的聚乙二醇“水泥”配方。

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.