微粒在眼底疾病中的应用研究现状及进展

Current progress on the study of microparticles in ocular fundus diseases

微粒是细胞凋亡或者受刺激后以出芽方式产生的细胞膜碎片。内皮细胞、血小板、巨噬细胞、淋巴细胞和肿瘤细胞等多种细胞都可以释放微粒。其生物学功能主要包括促进凝血、参与炎症反应和促进肿瘤生长。现有研究表明，增生型糖尿病视网膜病变（PDR）患者玻璃体中的微粒可以诱导内皮细胞增生迁徙以及新生血管的形成，从而促进PDR患者病理性新生血管的形成。氧化应激诱导视网膜色素上皮细胞产生的表达膜补体调节蛋白的微粒可能与老年性黄斑变性中玻璃膜疣形成有一定关系；淋巴细胞来源微粒（LMP）可以改变巨噬细胞中血管生成相关因子的基因表达模式，发挥重要的抗血管形成作用。LMP还可通过下调脾脏酪氨酸激酶的基因表达和上调p53及p21，最终激活半胱天冬酶-3，从而诱导视网膜母细胞瘤细胞的凋亡。但是微粒在眼底疾病中的研究尚属起步阶段，如何将微粒应用于临床防治眼底疾病是我们面临的一大难题。相信随着研究的进一步深入，微粒在眼底疾病中的应用会越来越广泛。

Microparticles are small vesicles that are released by budding of the plasma membrane during cellular activation and apoptotic cell breakdown. A spectrum of cell types can release microparticles including endothelial cells, platelets, macrophages, lymphocytes and tumor cells. Biological effects of microparticles mainly include procoagulant activity, inhibition of inflammation and cancer progression. The present study shows that vitreous microparticles isolated from proliferative diabetic retinopathy （PDR） stimulated endothelial cell proliferation and increased new vessel formation, promoting the pathological neovascularization in PDR patients. Oxidative stress induces the formation of retina pigment epithelium-derived microparticles carrying membrane complement regulatory proteins, which is associated with drusen formation and age related macular degeneration. Microparticles from lymphocyte （LMP） play an important role in anti-angiogenesis by altering the gene expression pattern of angiogenesis-related factors in macrophages. Besides, LMP are important proapoptotic regulators for retinoblastoma cells through reduction of spleen tyrosine kinase expression and upregulation of the p53-p21 pathway which ultimately activates caspase-3. However, how to apply the microparticles in the prevention and treatment of retinal diseases is a major challenge, because the study of the microparticles in the fundus diseases is still limited. Further studies conducted would certainly enhance the application of microparticles in the fundus diseases.