Phospholipids for enhancing cell-based neovascularization

描述(由申请人提供)：由于晚期血管疾病导致的氧气减少导致严重的临床问题，包括大量细胞死亡和由此导致的组织丢失。与治疗性血管生成的药理学方法相比，基于细胞的策略代表了生成毛细血管网络的直接方法。内皮细胞集落形成细胞(ECFC)是一类在低氧条件下表现出强大的血管生成能力的内皮祖细胞亚群，在体内可以形成功能性的血管网络。脂肪来源的干细胞(ASCs)是一种很有前途的促进血管生成和稳定新血管的细胞群。然而，基于细胞的治疗的成功受到限制，因为在将细胞移植到缺血组织环境中时，由于细胞凋亡而导致的快速细胞死亡，极大地减少了可用于参与血管生成的细胞数量。此外，最近的数据表明，来自老年捐赠者的细胞比来自年轻捐赠者的细胞更容易发生凋亡，这可能会损害不断增长的老龄化人口中基于自体细胞的组织修复方法的有效性。溶血磷脂酸(LPA)是一种存在于血清中的血小板衍生的脂质生长因子，是体内血管生成所必需的。此外，在体外促凋亡的微环境中，LPA可促进祖细胞的存活和活性。我们的中心假设是，LPA的局部和持续呈现将是一种有效的药物来抑制植入细胞的凋亡，从而使细胞能够长期分泌营养因子，并支持血管形成细胞的生存。这个项目的基本原理是，它将为氧气微环境的作用以及祖细胞如何参与组织修复提供新的见解，并为提高老年捐赠者细胞修复组织的效率提供新的方法。目的1.测定LPA缓释对人血管内皮细胞和血管内皮细胞在纤维蛋白凝胶内共培养中的抗凋亡和促血管生成作用。将评估局部释放LPA在低氧和血清降低条件下抑制细胞凋亡的能力，并量化由此产生的对这些刺激的血管生成反应。目的2.检测老年供者来源的ASCs与ECFCs共移植到LPA洗脱材料上，对小鼠后肢缺血模型的抗凋亡和促进血管生成的能力。这项拟议的研究具有创新性，因为它研究了一种新的方法，用于解决移植用于新生血管的细胞的损失，同时研究多种刺激在血管形成中的作用，这对这些方法的临床翻译和实现至关重要。我们将阐明LPA在将老年供者的ASCs移植到晚期血管疾病特有的缺血组织部位时，对延长ASCs活性的贡献。总而言之，这项研究将为提高移植细胞的效率提供一种新的方法，用于基于细胞的治疗，用于组织修复、伤口愈合以及组织工程和再生医学中的新兴应用。 公共卫生相关性：开发新的方法来提高植入后细胞的活性和功能，将极大地改善患有晚期血管疾病或无法愈合的组织缺损者的生活质量。我们试图确定磷脂的局部呈现是否可以抑制植入的血管形成细胞的凋亡，从而导致延长存活和增强新生血管。

DESCRIPTION (provided by applicant): The reduction of oxygen occurring as a result of advanced vascular diseases poses severe clinical problems including massive cell death and resultant tissue loss. Compared to pharmacological methods of therapeutic angiogenesis, cell-based strategies represent a direct approach to generate a capillary network. Endothelial colony forming cells (ECFCs) are a subpopulation of endothelial progenitor cells that exhibit robust angiogenic potential under hypoxic conditions and can form functional vascular networks in vivo. Adipose- derived stem cells (ASCs) are a promising cell population for promoting angiogenesis and potentially stabilizing new vessels. However, the success of cell-based therapies is limited by rapid cell death due to apoptosis upon implanting cells into ischemic tissue environments, dramatically reducing the number of cells available to participate in vasculogenesis. Additionally, recent data suggest that cells derived from older donors are more vulnerable to apoptosis than those from younger donors, potentially compromising the effectiveness of autologous cell-based approaches for tissue repair in the ever-growing aging population. Lysophosphatidic acid (LPA) is a platelet-derived lipid growth factor present within the serum and is required for angiogenesis in vivo. Additionally, LPA promotes the survival and viability of progenitor cells within pro-apoptotic microenvironments in vitro. Our central hypothesis is that localized and sustained presentation of LPA will be an effective agent to inhibit apoptosis in implanted cells, thus enabling prolonged secretion of trophic factors from cells and supporting the survival of vessel-forming cells. The rationale for this project is that it will provide new insights into the role of the oxygen microenvironment and how progenitor cells participate in tissue repair, and yield new approaches for enhancing the efficacy of tissue repair with cells from aged donors. Aim 1. Determine the anti-apoptotic and proangiogenic effect of sustained LPA release on co-cultures of human ECFCs and ASCs within fibrin gels. The ability of localized LPA release to inhibit apoptosis in hypoxic and serum-reduced conditions will be assessed, and the resulting vasculogenic response to these stimuli will be quantified. Aim 2. Determine the capacity of ASCs derived from aged donors and ECFCs to resist apoptosis and enhance vascularization when co-implanted on LPA-eluting materials into a murine ischemic hind limb model. The proposed research is innovative because it examines a novel approach for addressing the loss of cells implanted for neovascularization while investigating the role of multiple stimuli on vessel formation critical for the clinical translation and realization of these approaches. We will elucidate the contributions of LPA delivery on extending the viability of ASCs from older donors when implanted into an ischemic tissue site characteristic of advanced vascular disease. Collectively, this research will provide a novel approach for enhancing the efficacy of implanted cells for cell-based therapies for tissue repair, wound healing, and emerging applications in tissue engineering and regenerative medicine. PUBLIC HEALTH RELEVANCE: The development of new approaches to enhance cell viability and function upon implantation will greatly improve the quality of life for those who suffer from advanced vascular disease or non-healing tissue defects. We seek to determine if the localized presentation of a phospholipid can inhibit apoptosis in implanted vessel- forming cells, thereby resulting in prolonged survival and enhanced neovascularization.