2010-08-012024-05-13https://scholars.lib.ntu.edu.tw/handle/123456789/647648摘要：高膽固醇血症伴隨低密度脂蛋白膽固醇(LDL-C)的升高是冠狀動脈及周邊血管硬化疾病最重要的危險因子，而低密度脂蛋白（low-density lipoprotein，LDL）的氧化據信是一重要致病因素。過去幾年我們利用分子生化及藥理技術發現兩種自然存在於高膽固醇病人血液中的LDL次成份－L5及LpX，然而其濃度與心血管疾病的相關性卻未知。我們提出這個研究計劃的目的為釐清L5及LpX是否可以當做動脈硬化疾病的一個新的生物標記（Biomarker）。同時，我們也要分析各種高膽固醇病人其LDL生化組成（biochemical profile）之不同，並檢視在治療的過程中L5及LpX的改變，以期更清楚其臨床應用價值。我們訂出三個研究策略，預定以三年的時間來進行。第一個策略是從不同種類高膽固醇病人包括：家族性高膽固醇血症、糖尿病、腎病症候群、甲狀腺機能低下、原發性膽道肝硬化及其他阻塞性膽道疾病等類病患（各50名）的血液中分離LDL並以FPLC進行生化分析，比較治療前後各種LDL次成分的差異，並建立與臨床上動脈粥狀硬化之相關性。第二個策略是進一步以agarose、2D-PAGE gel、質譜儀分析L5及LpX的組成，找出其中特異的脂質或蛋白質成分。第三個策略則是探討L5及LpX中特殊的脂質或蛋白質成份（epitope）對人類動脈血管內皮細胞的影響，如細胞的生長、凋亡、基因表達等，以了解其生理學上的重要性。這個計劃的結果將有助於我們更進一步瞭解 LDL次成份在動脈硬化疾病所扮演的角色，同時更清楚其臨床應用價值，並期在臨床上建立一個新的診斷治療標的。<br> Abstract: Hypercholesterolemia with elevated plasma low-density lipoprotein (LDL) cholesterol (LDL-C) is a key risk factor for atherosclerotic disease, but the precise mechanism of LDL’s contribution to the initiation and progression of atherosclerosis remains elusive and is a core question for researchers who seek to prevent the disease. Since more than two decades ago, LDL oxidation has been considered as an important mechanism of LDL’s contribution to the initiation and progression of atherosclerosis. In the past several years, we have been able to make significant headway toward an answer by using fast protein liquid chromatography (FPLC) and related molecular techniques to identify two naturally occurring LDL species: an oxidized LDL named L5 in hypercholesterolemic plasma, and an anti-oxidative LDL named LpX in patients with primary biliary cirrhosis (PBC). However, their clinical significance and correlation with disease status remains elusive.The working hypothesis of the proposed studies is that the relative risk for developing atherosclerotic cardiovascular disease depends on a close interplay between the distinct subfractions of oxidized (L5) and anti-oxidative LDL species (LpX). These LDL subfractions have distinct biochemical profiles before and after treatment in each disease entity and their presence or absence can serve as novel “biomarkers” for clinical atherosclerosis. These LDLs can also exhibit distinct physiological effects on the growth and gene expressions in human arterial endothelial cells. Therefore, our primary goal in this proposal is to investigate the potential role of LpX and L5 as novel “biomarkers” for clinical atherosclerosis. In addition, we also want to characterize the biochemical profiles of LDL in hyperlipidemic patients during disease treatment, and thus determining their clinical significance.The studies we propose for this 3-year project are organized within three specific aims. The first aim is to perform FPLC LDL profiling on LDLs isolated from a wide variety of hypercholesterolemic patients, such as Familial hypercholesterolemia (FH), Diabetes Mellitus (DM), nephrotic syndrome (NS), hypothyroidism, primary biliary cirrhosis (PBC) or other obstructive biliary diseases. Patients will be recruited from NTUH clinics upon approval of projects by the Institutional Review Board, and their blood samples will be obtained in the clinical facilities. Experiments for all three aims will be performed simultaneously in different laboratories. We want to test the hypothesis that the LDL profiles differ in these patients especially in patients with coronary artery disease. The second aim is to identify the specific modified lipids and/or proteins/peptides in Lp-X and L5 (by agarose gel, 2D gelelectrophoresis and mass spectrometry) which can serve as molecular epitopes contributing to the development/suppression of atherosclerosis. The third aim is to investigate whether these LDLs and their epitopes will exhibit biological effects in vitro that are consistent with their contributions to atherogenesis in vivo. This research will provide the basis for more mechanistically relevant therapeutic strategy to retard the initiation and progression of atherosclerosis using specific LDL species as biomarkers and thereby to minimize morbidity and mortality in high-risk populations.高膽固醇血症低密度脂蛋白內皮細胞動脈粥狀硬化生物標記生長因子基因調控Hypercholesterolemia • low-density lipoprotein • endothelial cell • atherosclerosis • cardiovascular biomarker • growth factor • gene expression