c-kit+干细胞在人工血管组织再生中的作用机制研究

Endothelization and smooth muscle cells remodeling are crucial for vascular grafts regeneration. The origin of endothelial cells and smooth muscle cells in the regeneration process is unclear. In our previous study, c-kit+ stem cells were found in the graft during the regeneration process. However, the characterization, origin and function are still unknown. In the present project, c-kit+ stem cells will be isolated from the explanted vascular graft by FACS and expanded in vitro. We will test its’ stemness characterization including clonogenicity, self renewal and differentiation. Besides, the cells will be labeled by AIE and seeded into the vascular grafts. And then the grafts will be implanted into the rat abdominal artery to investigate the role of c-kit+ in the regeneration process by the molecular imaging method. In addition, we will further investigate the effect of the structure (fiber diameter, graft pore size) and bioactive molecules (Fibronectin，PDGF-bb, et al) to regulate the behavior of the c-kit+ stem cells, including proliferation, differentiation and paracrine. Our aim of this project is to explain the role of the c-kit+ stem cells in the vascular graft regeneration process and fabricate a promising vascular graft, which could regenerate into a functional artery by recruiting the stem cells and modulating its differentiation.

内皮化与平滑肌重构是人工血管再生的关键。目前对参与内皮与平滑肌层再生的细胞来源问题还没有清楚认识。我们前期研究发现,c-kit阳性干细胞参与了人工血管体内再生过程,但其干细胞特性、来源以及在血管再生过程中的作用机制尚不清楚。本项目拟采用FACS技术从植入体内不同时间的人工血管中分离获得c-kit阳性细胞,研究其特性、来源以及分化能力。该细胞经体外扩增后,利用新型荧光分子探针AIE进行标记,再种植到血管支架中,植入大鼠体内,利用分子影像技术研究其c-kit阳性细胞对血管再生的作用机制。利用静电纺丝技术与表面修饰技术制备不同结构和功能的PCL人工血管，考察纤维直径、孔径及功能分子(Fibronectin、PDGF-bb等)对c-kit干细胞增殖、分化与旁分泌的影响。通过本项目的研究阐明c-kit阳性干细胞参与人工血管组织再生的机制, 制备出能够特异性募集、诱导干细胞参与血管再生重构的人工血管。

内皮化与平滑肌重构是人工血管再生的关键。参与内皮与平滑肌层再生的细胞来源问题还没有清楚认识。本项目试图阐述干细胞在人工血管再生中的作用，同时从材料结构设计与表面修饰出发，制备性能优良的人工血管。本项目主要研究内容包括1）设计并制备获得四种由双层结构静电纺丝人工血管以及一种负载可控释放DKK3细胞因子人工血管支架，通过调控ckit+干细胞在人工血管支架中的迁移行为，证明其在人工血管组织再生中的关键作用。2）制备获得三种具有特殊结构与表面功能的新型人工血管以促进人工血管体内组织再生，包括通过制备纤维周向取向排列支架结构实现体内原位诱导平滑肌取向排列再生；制备酶控NO原位局部靶向释放的人工血管支架，实现促人工血管快速内皮化；负载白藜芦醇活性分子调控巨噬细胞表型转化促人工血管组织再生。 3）开展人工血管原位长期植入的动物评价以及疾病动物模型评价的研究。通过本项目的实施，推动了人工血管领域的发展，提供了重要理论基础并获得了几种有望临床转化的人工血管支架材料。