Development of therapeutic agents and gene therapy by inhibiting new vessel formation

在糖尿病视网膜病变的发病机制中，高血糖导致血管屏障功能破坏和视网膜缺血。视网膜水肿和出血伴随着血管屏障的破坏。除了视网膜内皮细胞损伤和凝血功能异常外，严重的视网膜水肿还会加速视网膜毛细血管阻塞和视网膜缺血。对山形大学医院就诊患者的流行病学调查表明，视网膜病变的进展导致视力下降，提示预防新生血管的形成是非常重要的。糖尿病视网膜病变的血管病变是以多种细胞因子和生长因子为基础的，包括血管内皮生长因子、转化生长因子-β超家族等。为了防止新生血管的形成，我们研究了调节血管内皮细胞功能的方法。细胞外基质的形成与细胞功能和细胞外基质…有关更多的是由细胞因子调节的。本研究发现透明质酸合成受透明质酸合成酶(HAS)调节，透明质酸合成酶(HAS)受转化生长因子-β和血小板衍生生长因子-B(PDGFR-B)调节，转化生长因子-β对透明质酸合成活性的调节是调控新生血管形成的候选途径之一。玻璃体切割术中获得的玻璃体标本的临床研究表明，眼部新生血管的形成受血管生成因子和血管抑制因子之间的平衡调节。我们已经证明激活素A在玻璃体中表达，并起到血管抑制因子的作用。激活素A浓度太低，不能抑制新生血管的形成。激活素受体的转染改善了内皮细胞的反应能力，这可能是另一种基因治疗的候选方法。另一种抑制新血管形成的策略是调节周细胞。转化生长因子-β抑制周细胞增殖，纤溶酶刺激周细胞增殖。这两个因素是相互竞争的。周细胞的调控也是基因治疗的另一个候选者。观察血管内皮生长因子、血小板生长因子、白介素6和肿瘤坏死因子α在增生性视网膜病变玻璃体中的表达。探讨细胞因子/生长因子与临床特征的相关性，探讨细胞因子/生长因子在糖尿病视网膜病变发病机制中的作用。这些因素是相互关联的。这些证据提出了今后研究基因治疗方法的主要靶点势在必行。较少

In the pathogenesis of diabetic retinopathy, hyperglycemia causes breakdown of vascular barrier function and retinal ischemia. Retinal edema and bleeding follow the breakdown of vascular barrier. In addition to retinal endothelial damage and abnormality of blood coagulation, severe retinal edema acceleratesthe retinal capillary obstruction andretinal ischemia. The epidemiological investigation of the patients visiting Yamagata University Hospital revealed tha the progression of retinopathy causes the vision, which has suggested that the prevention of new vessel formation is very important. The vasculopathy in diabetic retinopathy is based on many cytokines and growth factors, including vascular endothelial growth factor (VEGF), transforming growth factor-β (TGF-β) superfamily and others. To prevent the new vessel formation, we investigated the methods to regulate the funtions of vascular endothelial cells. The extracelluar matrix (ECM) formation is related to the cell funtions and ECM … More is regulated by cytokines. The present study has revealed ethat the hyaluronan formation is regulated by hyaluronan synthase (HAS), and HAS is regulated by TGF-β and PDGF-BB.The regulation of HAS acitiity by TGF-β is one of the candidates to regulated new vessel formation. The clinical study using vitreous somples obtained during vitrectomy has revealed that the ocular new vessel formation is regulated by the balance between the angiogentic factor and angiostatic factors. We have shown that activin A was expressed in the vitreous and acted as angiostatic factor. The concentration of activin A was too low to inhibit the new vessel formation. The transfection of activin receptors improved the responsibility of the endothelial cells, which may be another candidates of gene therapy. Another strategy to inhibit new vessel formation is to regulate the pericytes. The proliferation of pericytes is inhibited by TGF-β and stimulated by plasmin. These 2 factors competed each other. The regulation of pericytes is also another candidates of gene therapy. The Expressions of VEGF, PlGF, interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in the vitreous obtained from PDR eyes were investigated. The correlation among cytokines/growth factors and clinical characteristics was inquired to know the roles in the pathogenesis of diabetic retinopathy. These factors were correlated each other. These evidences proposed the issue that it is mandatory to investigate the main target to develop the methods of the gene therapy from now on. Less