iPS细胞联合PDGF-β重塑视网膜新生血管的实验研究

Retinal vascular diseases have become one of the major causes of blindness in the world. Retinal neovascularization is the core issue of these diseases. Due to poorly developed capillary wall, the pathological new vessels are easy to break and leak and therefore can lead to other retinal complications and vision loss. Instead of following the traditional thinking of "suppress the process of neovascularization", we propose to reconstruct retinal new vessels. Because of the important role of pericytes in reconstruction of retinal new vessels, we plan to study in vitro the possibility of iPS cell differentiating into pericytes induced by retinal vessel endothelial cells under hypoxia. We will also conduct in vivo experiments to observe the distribution patterns of pericytes during the formation of both normal and pathological retinal vessels. The distribution pattern on mice retina of iPS cells after intravitreal injection, the rate of differentiation to pericytes, and the effects on retinal vessel formation will be assessed. We will further investigate the effects of iPS cells on retinal new vessels under PDGF-β induction. Retinal new vessel reconstruction can better mimic the process of retinal neovacularization and therefore may lead to better understanding of its pathogenesis. With the success of the project, we may be able to shed a light for the prevention and treatment of many retinal vascular diseases.

视网膜血管性疾病已经成为世界性主要致盲眼病，视网膜新生血管生成是该类疾病的核心问题。病理性新生血管管壁不完整、质脆、易渗漏，是导致视网膜并发症产生及视功能损害的主要原因。本课题摆脱"抑制新生血管"这一传统思路的束缚，提出"重塑新生血管"的新观点。基于视网膜血管周细胞在血管壁重塑中的重要作用，我们拟通过体外实验，研究缺氧环境中iPS细胞在视网膜血管内皮细胞诱导下向血管周细胞转化的可能性；通过体内实验，研究周细胞在正常血管生成和病理性新生血管生成过程中的分布规律；观察iPS细胞玻璃体腔注射后在小鼠视网膜分布情况、向周细胞分化的效率、对视网膜血管生成的影响；在此基础上，观察PDGF-β诱导下，iPS玻璃体腔注射对视网膜血管生成的影响。本课题提出"血管重塑"的思路，更加符合疾病的病理生理过程，项目的成功开展，必将对视网膜血管性疾病的防治产生深远影响。

在国家自然科学基金资助下，该项目严格按照计划书内容开展相关研究。初步研究结果表明，IPS细胞在体外缺氧环境诱导下，可以向周细胞转化。体内实验表明，从P7至P21，伴随OIR小鼠视网膜的发育，VEGF-A、PDGF-BB、PDGFR-β的mRNA均出现先增高后降低的表达趋势，PDGF-BB和PDGFR-β在OIR小鼠视网膜血管生成中起到重要作用。从P7至P21，伴随OIR小鼠视网膜的发育，Angiopoietin-1、Tie-2的mRNA出现先增高后降低的表达趋势，Angiopoietin-1和Tie-2在OIR小鼠视网膜血管成熟中起到重要作用。