2015-08-012024-05-14https://scholars.lib.ntu.edu.tw/handle/123456789/656715摘要：糖尿病視網膜病變(DR)，尤其是增殖性糖尿病視網膜病變(PDR)是造成失明的主要原因之一。雖然近年來有抗血管新生因子療法及微創玻璃體切除手術的發展，但是PDR 的視力預後仍不佳。因此充分了解其致病機轉以及尋找更有效的治療方法以防止PDR 之惡化，是十分迫切的課題。臨床經驗及大型之臨床試驗結果顯示，接受一般血糖控制之糖尿病患，即使在研究結束後，接受更積極之血糖控制，其日後DR 之惡化程度仍高於原先一開始就接受積極血糖治療的病患，這種現象稱為「新陳代謝記憶」。近年來之研究顯示，高血糖引起併發症和「表觀遺傳(epigenetics)」有關。目前已知的表觀遺傳機制包括DNA 甲基化、改變組蛋白(histone)尾端或染色體結構及微型RNA (microRNAs)。血管內皮細胞生長因子(VEGF)可以促使新生血管產生，而結締組織生長因子(CTGF)則可促使結締組織增生，引起牽引性視網膜剝離，導致失明。近來之研究發現，高血糖可以透過表觀遺傳之機制，促進CTGF 之活化及生成，進而影響器官之癒合過程。這些現象在肺、肝、腎及心臟均有大量之研究，但在眼科方面則少有報告。因此我們假設外在環境之因素，例如高血糖可以經由表觀遺傳的方法調控 CTGF 在視網膜細胞的表現，進而在PDR 的過程中扮演重要的角色．本計畫是一個為期三年的實驗，第一年我們將利用視網膜血管內皮細胞RF/6A 及視網膜色素上皮細胞（ARPE19）為對象，研究在高血糖及TGF-β刺激下是否能引起組蛋白中離氨基酸（lysine）在H3K4 及H3K9 位置上之甲基化，進而調控CTGF 的產生．第二年我們將探討在RF/6A 及ARPE19 細胞中，以高血糖及TGF-β刺激是否能引起microRNA，尤其是miR-133 之改變，進而調控CTGF 的合成．第三年則進行動物實驗，利用streptozotocin 引發之糖尿病鼠模式研究CTGF 在視網膜之表現，並證實『新陳代謝記憶』之機轉。希望藉由本次之研究能更明瞭 PDR 中CTGF 之調控及其作用機轉，也為PDR 之防治探討一條新的治療方向。<br> Abstract: Proliferative diabetic retinopathy (PDR) represents the most common cause of blindness in peopleof working age. Despite significant advances in the understanding of the pathogenesis of PDR and thedevelopment of new treatment techniques, such as anti-VEGF therapy and microincision vitrectomy, theprognosis of PDR is still unsatisfactory. Therefore; it is an important issue to search for new modalities ofprevention and treatment of PDR. Clinical and epidemiologic evidence have shown that PDR continuesbeyond the point when good glycemic control has been achieved, and have suggested a ‘‘metabolicmemory’’ phenomenon. Recent data have suggested an important role of epigenetic modifications in themetabolic memory phenomenon associated with the continued progression of diabetic complications. PDRis characterized by the retinal neovascularization and tractional retinal detachment. Vascular endothelialgrowth factor (VEGF) and connective tissue growth factor (CTGF) may contribute to the new vesselsformation and fibrotic change of PDR respectively. The aim of our study was to investigate the role ofepigenetic mechanisms in the regulation of retinal CTGF expression in the development of PDR and also inthe metabolic memory associated with its failure to halt the progression of PDT even after re-establishmentof normal glycemic control.This project will be performed in three years. In the first year, we will investigate the role ofepigenetic chromatin marks histone H3K4 and H3K9 lysine methylation (H3Kme) in TGF-–induced CTGFgene expression in retinal vascular endothelial cells (RF/6A) and ARPE 19 cells under normal andhigh-glucose conditions. In the second year, we will investigate the miRNA, especially miR-133,expression patterns involved in TGF-–induced CTGF gene expression in retinal vascular endothelial cells(RF/6A) and ARPE 19 cells under normal and high-glucose conditions. Finally, in the third year we willevaluate the epigenetic modification of CTGF expression in streptozocin-induced diabetic rat model in vivoand confirm the “metabolic memory” phenomenon.Through our intensive study, the epigenetic mechanisms of modulation the expression offibrogenic factor CTGF in the development of PDR will be further understood. The “metabolic memory”phenomenon in the progression of PDR will be confirmed. Understanding the mechanism of CTGFmodulation may provide the pharmacologic and other therapies which could reverse these modifications inthe levels of histone methylation or microRNA and have potential protective effects for preventing PDRprogression.