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的破坏和视网膜缺血。视网膜水肿和出血是血管屏障破坏的结果。严重的视网膜水肿除了导致视网膜内皮细胞损伤和凝血功能异常外，还可加速视网膜毛细血管阻塞和缺血。对山形大学医院就诊患者的流行病学调查显示，视网膜病变的进展导致视力下降，这表明预防新血管形成非常重要。糖尿病视网膜病变的血管病变是由多种细胞因子和生长因子引起的，包括血管内皮生长因子（VEGF）、转化生长因子-β（TGF-β）超家族等。为了防止新血管的形成，我们研究了调节血管内皮细胞功能的方法。细胞外基质（extracelluar matrix，ECM）的形成与细胞功能及ECM的形成密切相关 ...更多信息 是由细胞因子调节的。本研究揭示透明质酸合成酶（hyaluronan synthase，HAS）调控HAS的形成，而HAS受TGF-β和PDGF-BB的调控，TGF-β对HAS活性的调控是调控新生血管形成的候选因素之一。利用玻璃体切除术中获得的玻璃体进行的临床研究表明，眼部新血管的形成受血管生成因子和血管生成抑制因子之间的平衡调节。我们已经表明，激活素A在玻璃体中表达，并作为血管生成抑制因子。激活素A的浓度太低而不能抑制新血管形成。激活素受体的转染提高了内皮细胞的反应性，这可能是基因治疗的另一个候选者。抑制新血管形成的另一个策略是调节周细胞。周细胞的增殖受TGF-β的抑制，并受纤溶酶的刺激。这两个因素相互竞争。周细胞的调控也是基因治疗的另一个候选者。检测PDR玻璃体中VEGF、PlGF、白细胞介素6（IL 6）和肿瘤坏死因子α（TNF α）的表达。探讨细胞因子/生长因子与糖尿病视网膜病变临床特征的相关性，以了解其在糖尿病视网膜病变发病中的作用。这些因素之间存在一定的相关性。这些证据提出了这样一个问题，即从现在开始，研究主要靶点以开发基因治疗方法是强制性的。

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