血清Galectin-7濃度在診斷阻塞性冠狀動脈疾病上的應用

The Application of Serum Galectin-7 Levels in the Diagnosis of Obstructive Coronary Artery Disease

郭俊亨(Chun-Heng Kuo)

指導教授 ： 李弘元

國立臺灣大學/醫學院/臨床醫學研究所/碩士(2018年)

https://doi.org/10.6342/NTU201803517

摘要

背景
動脈粥狀硬化是導致心血管疾病最常見且重要的致病機轉，動脈粥狀硬化及其併發症更是人類的主要死因之一。因此，治療與預防動脈粥狀硬化相關併發症的產生，以減低罹病率與死亡率，是臨床上一個非常重要的問題。臨床醫師會依臨床判斷來選擇有需要的病人，進一步接受冠狀動脈血管攝影，來診斷及治療冠狀動脈疾病。然而，目前用來挑選病人的臨床策略仍不夠好，執行冠狀動脈血管攝影後，高達20-42%的病人結果血管並無阻塞。最近，我們利用apolipoprotein E基因剔除鼠，以next-generation sequencing的技術比較動脈硬化組與對照組主動脈組織的mRNA expression profile，試著尋找可能參與動脈粥狀硬化形成的候選基因，結果發現galectin-7的表現有顯著增加。Galectin-7是galectins家族的一員，是一種β–galactoside的結合蛋白，主要存在於人類表皮中。文獻中指出，galectin-7參與傷口癒合，能調控角質細胞的凋亡、增生、分化及遷移。此外，galectin-7也表現在冠狀動脈繞道手術後動脈化的移植靜脈中，卻不表現在沒有動脈化的移植靜脈中，顯示galectin-7與血管調適血流壓力的功能有關，而血流壓力在動脈粥狀硬化上扮演一定的角色。
假說與目標
綜合以上，我們提出的假說是，動脈粥狀硬化過程會誘發galectin-7。動脈上的galectin-7會增加表現量及造成血清galectin-7濃度的上升，兩者與動脈粥狀硬化相關。血清galectin-7的濃度能幫助預測冠狀動脈疾病，以決定是否需要進一步執行冠狀動脈血管攝影。本研究透過動物研究(specific aim 1)和人類的橫斷面研究(specific aim 2)探討此一假說。
材料與方法
在動物實驗部分(specific aim 1)，我們使用apolipoprotein E基因剔除鼠，分別餵食15週正常飲食(ND組)與高膽固醇飲食(AD組)。利用免疫組織染色及西方墨點法，比較galectin-7蛋白，在兩組老鼠主動脈中，表現量的不同。此外，我們也比較兩組老鼠血清galectin-7濃度的不同。在人類實驗部分，我們利用免疫組織染色去比較正常人與有冠狀動脈疾病的患者，galectin-7蛋白在動脈的表現有無不同。在人類橫斷式研究中(specific aim 2)，我們收錄407位疑似冠狀動脈疾病並且前來台大醫院心臟科門診就診的病人。在接受心導管檢查執行冠狀動脈血管攝影後，依結果將這些病人分成有阻塞性冠狀動脈疾病(291位)及無阻塞性冠狀動脈疾病(116位)兩組。我們會比較這兩組患者，血清galectin-7的濃度是否不同。
結果
AD組老鼠的galectin-7蛋白在主動脈的表現量顯著高於ND組(p=0.0266)。AD組老鼠的血清galectin-7濃度也顯著高於ND組(p=0.015)。
在冠狀動脈疾病的人身上，使用免疫組織染色發現galectin-7蛋白在冠狀動脈上會顯著表現。有阻塞性冠狀動脈疾病的患者，血清galectin-7的濃度顯著高於無阻塞性冠狀動脈疾病的患者 (p=0.027)。在調整過年紀、性別及其他臨床上重要的干擾因子後，血清galectin-7濃度用來預測阻塞性冠狀動脈疾病的勝算比是1.55 (95%信賴區間 1.04-2.31 p=0.030)。ROC曲線分析下，加上血清galectin-7濃度的模型預測能力(Area under the ROC curve, AUC)是0.7566，而沒有血清galectin-7濃度的模型預測能力(AUC)是0.7206 (p=0.18)。
結論
動脈組織中galectin-7蛋白的表現量與血清galectin-7的濃度與動脈粥狀硬化有顯著正相關。利用血清galectin-7濃度的模型預測阻塞性冠狀動脈疾病的能力(AUC)是0.7566。

關鍵字

阻塞性冠狀動脈疾病 ； 動脈粥狀硬化 ； galectin-7 ； 預測模型

並列摘要

Background
Atherosclerosis is the most important pathogenesis of cardiovascular diseases (CAD), and is a major cause of death in humans all over the world. Therefore, prevention and treatment of CAD is an important issue for human health. Before invasive cardiac catheterization for definite diagnosis and intervention, clinicians would select targeted patients based on clinical scenario. However, current clinical strategies to select targeted patients are not good enough, with a 20-42% of patients with a negative finding by coronary angiography (CAG). Recently, using next-generation sequencing to search candidate genes in atherosclerosis, we have compared the mRNA expression profile in atherosclerotic plaques and normal aortic tissues in apolipoprotein E knockout (Apo E -/-) mice. Our results showed that galectin-7 mRNA is up-regulated in atherosclerotic plaques. Galectin-7, a member of the galectins family, is a β–galactoside-binding protein, which is expressed in the human epidermis. Galectin-7 is involved in wound healing. It can regulate the apoptosis, proliferation, differentiation and migration of keratinocytes. Besides, galectin-7 expressed in arteries, but was absent in veins, suggesting that galectin-7 may be involved in the adaptation of biomechanical forces, which play a role in the process of atherosclerosis.
Hypothesis and Aim
We hypothesized that galectin-7 would be induced during the process of atherosclerosis. Increased galectin-7 expression and elevated serum galectin-7 levels would be associated with atherosclerosis. Serum galectin-7 levels could assist the prediction of CAD to decide if CAG is indicated. This project tested the hypothesis by an animal study (specific aim1), and a human cross-sectional study (specific aim 2).
Material and Methods
In the animal study (specific aim 1), we used Apo E -/- mice fed with normal diet (ND group) or atherogenic diet (AD group) for 15 weeks. By using immunohistochemistry (IHC) stain and Western blot, we compared the expression of galectin-7 in aorta. We also compared mouse serum galectin-7 levels. In a human study, IHC stain was performed to compare the expression of galectin-7 in human arteries between a normal subject and a subject with CAD. In a human cross-sectional study (specific aim 2), we recruited 407 subjects who were suspected CAD and visited cardiologist outpatient departments at National Taiwan University Hospital. They were categorized into subjects with or without obstructive CAD by the results of CAG. We compared serum galectin-7 levels and developd a prediction model for obstructive CAD.
Results
The expression of galectin-7 in aorta was significantly higher in AD group than in ND group (p=0.0266). The mouse serum glaectin-7 levels were also higher in AD group than in ND group (p=0.015).
In a subject with CAD, galectin-7 was highly expressed in the plaque area of human coronary arteries by IHC stain. Serum galectin-7 levels were significantly higher in subjects with obstructive CAD than those without obstructive CAD (p=0.027). Odds ratio of serum galectin-7 levels for prediction of subjects with obstructive CAD was 1.55 (95% CI, 1.04-2.31, p=0.030), adjusted for age, gender and other clinically important confounders. In ROC curve analysis, the prediction power (Area under the ROC curve, AUC) of the serum galectin-7 levels based model was 0.7566, compared to 0.7206 of a model without serum galectin-7 levels (p=0.18).
Conclusion
The expression of galectin-7 in arteries and serum galectin-7 levels are significantly positively associated with atherosclerosis. The prediction power (AUC) of a serum galectin-7 based model for subjects with obstructive CAD is 0.7566.

並列關鍵字

obstructive coronary artery disease ； atherosclerosis ； galectin-7 ； prediction model

參考文獻

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