Atherosclerotic plaque injury-mediated murine thrombosis models: advantages and limitations

Abstract

In spite of current treatment strategies, myocardial infarction and stroke are still major causes of death worldwide. These events are triggered by damage of an atherosclerotic plaque, resulting in occlusive thrombus formation. Mouse studies have significantly contributed to our understanding of the mechanisms of atherogenesis and of thrombosis following plaque injury, but the extent to which the mouse serves as an accurate model of human disease is open to discussion. In this review, we provide a detailed overview and comparison of the described mouse models for atherothrombosis including their (dis)advantages. Herein guidance is provided on how to select a suitable atherothrombosis model for research questions primarily relevant to the field of thrombosis.     

炎症反应在易损斑块中的作用及其机制研究进展

炎症反应在易损斑块的形成和进展中发挥重要作用,同时调控血管局部病变及全身炎症状态。一些促炎性细胞和炎症因子使斑块纤维帽的抗张强度降低,坏死脂质内核增大,血管机械稳定性丧失和斑块破裂;另一方面,炎症反应的激活和代谢紊乱也会引起内皮功能不全、斑块侵蚀进而导致血栓形成。该过程主要由巨噬细胞和淋巴细胞等多种炎症细胞参与,并受到多种因素调控,包括胆固醇结晶和脂质递质、血管剪切力、血管新生及斑块内出血等。此外,机体还存在一些抑炎性分子,能避免易损斑块向破裂或侵蚀进展。促炎和抗炎反应的平衡影响急性冠状动脉事件的发生。因此,以炎症反应为靶点,筛选出有易损斑块的患者并干预,或可减少急性冠状动脉事件的发生和改善预后,具有重要临床价值。     

From vulnerable plaque to atherothrombosis

Plaque rupture precipitates approximately 75% of all fatal coronary thrombi. Therefore, the plaque prone to rupture is the primary focus of this review. The lipid-rich core and fibrous cap are pivotal in the understanding of plaque rupture. Plaque rupture is a localized process within the plaque caused by degradation of a tiny fibrous cap rather than by diffuse inflammation of the plaque. Atherosclerosis is a multifocal disease, but plaques prone to rupture seem to be oligofocal at most.     

诱导型环氧合酶高表达增加兔主动脉粥样硬化斑块易损性

目的:探讨诱导型环氧合酶（COX-2）在兔主动脉粥样硬化(atherosclerosis,AS)组织中的表达及其与斑块易损性之间的关系。方法: 以高脂饲料喂养建立兔主AS模型,并与正常饲料组对照。喂养12周后,取兔主动脉标本,行HE及免疫组化染色,观察COX-2、基质金属蛋白酶-2（MMP-2）、Ⅰ型和Ⅲ型胶原在AS斑块组织中的表达。结果: COX-2仅见于AS斑块,正常动脉壁无表达。AS组COX-2免疫组化染色强度均显著高于正常对照组（P<0.05）。AS组Ⅰ、Ⅲ型胶原和MMP-2免疫组化染色强度均显著高于正常对照组（P<0.05）,Ⅰ/Ⅲ型胶原的比例增加。结论: COX-2在兔主动脉AS斑块中的高表达可能增加斑块的易损性。     

SLE, atherosclerosis and cardiovascular disease

Atherosclerosis is an inflammatory disease and the major cause of cardiovascular disease (CVD) in general. Atherosclerotic plaques are characterized by the presence of activated immune competent cells, but antigens and underlying mechanisms causing this immune activation are not well defined. During recent years and with improved treatment of acute disease manifestations, it has become clear that the risk of CVD is very high in a prototypic autoimmune disease, systemic lupus erythematosus (SLE). SLE-related CVD and atherosclerosis are important clinical problems but may in addition also shed light on how immune reactions are related to premature atherosclerosis and atherothrombosis. A combination of traditional and nontraditional risk factors, including dyslipidaemia (and to a varying degree hypertension, diabetes and smoking), inflammation, antiphospholipid antibodies (aPL) and lipid oxidation are related to CVD in SLE. Premature atherosclerosis in some form leading to atherothrombosis is likely to be a major underlying mechanism, though distinctive features if any, of SLE-related atherosclerosis when compared with 'normal' atherosclerosis are not clear. One interesting possibility is that factors such as inflammation or aPL make atherosclerotic lesions in autoimmune disease more prone to rupture than in 'normal' atherosclerosis. Whether premature atherosclerosis is a general feature of SLE or only affects a subgroup of patients remains to be demonstrated. Treatment of SLE patients should also include a close monitoring of traditional risk factors for CVD. In addition, attention should also be paid to nontraditional risk factors such as inflammation and SLE-related factors such as aPL. Hopefully novel therapeutic principles will be developed that target the causes of the inflammation and immune reactions present in atherosclerotic lesions.     

Exploring the role of extracellular matrix proteins to develop biomarkers of plaque vulnerability and outcome

Cardiovascular disease (CVD) is the most common cause of death in industrialized countries. One underlying cause is atherosclerosis, which is a systemic disease characterized by plaques of retained lipids, inflammatory cells, apoptotic cells, calcium and extracellular matrix (ECM) proteins in the arterial wall. The biologic composition of an atherosclerotic plaque determines whether the plaque is more or less vulnerable, that is prone to rupture or erosion. Here, the ECM and tissue repair play an important role in plaque stability, vulnerability and progression. This review will focus on ECM remodelling in atherosclerotic plaques, with focus on how ECM biomarkers might predict plaque vulnerability and outcome.     

Psychological stress increases expression of aortic plaque intercellular adhesion molecule-1 and seruminflammatory cytokines in atherosclerotic rabbit model

Plaque rupture,platelet aggregation,and thrombogenesis are the main mechanisms of acute coronary syndrome (ACS),and inflammation factors play key roles in plaque unstability.Psychological stress promotes acute inflammatory response,leading to increased circulating levels of C-reactive protein (CRP),IL-6,and serum intercellular adhesion molecule (sICAM)-1.But it is not clear that whether psychological stress has a direct effect on atherosclerotic plaque stability.The purpose of this study was to investigate effects of chronic psychological stress on inflammatory marker (ICAM-1 ) in atherosclerotic plaque,and inflammatory markers in peripheral blood.Materials and methods Sixty male rabbits were randomized into 2 groups:the control group (n =10) and the atherosclerotic group (n =50).The latter were fed on high fatty diet and were given a large dose of vitamin D3 (3 600 000IU/kg) via intraperitoneal injection.After 8 weeks,the atherosclerotic model was estaslished.Then the 50 atherosclerotic model rabbits were divided into 3 subgroups:no-stress subgroup (n = 16),physiological stress subgroup (n = 16) and psychological stress subgroup (n =18).In physiological stress subgroup and psychological stress subgroup,drinking was cut from twice a day to once a day.At the same time,psychological stress subgroup was given empty bottle stress,and this process lasted for 2 weeks.One hour after the last stress,the blood samples were collected and the serum levels of CRP,IL-6 amd ICAM-1 were tested by radioimmunoassay or enzyme linked immunosorbent assay.The aorta and heart were extracted for pathology examination,and the express of ICAM-1 was tested by immunohistochemical examination.Results (1) After effective atherosclerotic animal model construction,the expression of ICAM-1 in aorta was higher in atherosclerotic group than that in control group (P＜0.01),and was notably higher in psychological stress subgroup than that in no-stress subgroup or in physiological stress subgroup (2.18±0.17 vs 1.58±0.22,1.22±0.15,P＜0.001,respectively).The expression in physiological stress subgroup was higher than that in no-stress subgroup (584±0.22 vs 1.22±0.15,P=0.001).(2) The serum level of IL-6 (51.80±4.60 pg/ml vs 27.60±4.19 pg/ml,8.01±1.39 pg/ml,7.83±1.37 pg/ml),sICAM-1 ( 1.24±0.25 vs 0.85±0.09,0.62±0.17,0.57±0.11),CRP ( 1.004±0.37 vs 0.90±0.29,1.01±0.22,0.71±0.13) in psychological stress group were significantly higher than that in other groups (All P＜0.05).There was a positive relationship between the serum level of CRP,IL-6 and ICAM-1 and the expression of ICAM-1 in aorta wall ( r =0.59,r =0.75,r =0.87,P＜0.01,respectively).Conclusions Psychological stress induces an increased expression of ICAM-1 in aortic atherosclerotic plaque,a higher serum level of CRP,IL-6,and sICAM-1 expression.Psychologial stress has a direct effect on the transition from stability to unstability through in-plaque and out-plaque inflammation.The serum level of CRP,IL-6 and ICAM-1 can reflex the inflammatory degree in atherosclerotic plaque.(J Geriatr Cardiol 2008;5:235-242)     

炎症和动脉血栓形成

动脉粥样硬化已不再被考虑是由于脂质代谢异常的疾病,事实上动脉粥样硬化可能是在临床出现征状之前已存在数十年的炎症过程,一旦启动特殊的细胞因子介导的事件在动脉壁中进行,炎症的生物标志物如C反应蛋白是有用的。     

FD-OCT识别不稳定斑块及判断斑块性质的临床研究

目的 探讨频域光学相关断层扫描（frequnce domain optical coherence tomography, FD-OCT）及血管内超声(intravascular unltrasound, IVUS)识别冠状动脉不稳定斑块,并识别其性质,分析FD-OCT与IVUS成像差异。方法 收集2014年01月～2015年01月在哈尔滨医科大学附属第二医院心内科接受左主干介入手术的45例患者的临床资料,在介入手术术前及术后分别运用FD-OCT和（或）IVUS成像,判断是否存在不稳定斑块、不稳定斑块破裂及识别斑块性质。结果 FD-OCT检测出不稳定斑块6处,不稳定斑块破裂2处,支架内不稳定斑块破裂1处,IVUS未能对不稳定斑块及斑块破裂进行识别。FD-OCT识别纤维斑块13处、脂质斑块7处、钙化斑块9处,IVUS分别识别9处、3处、9处。结论 在分辨斑块性质、不稳定斑块及判断是否存在斑块破裂的过程中,FD-OCT明显优于IVUS,但FD-OCT及IVUS对钙化斑块的识别无明显差异。     

胍丁胺与动脉粥样硬化炎症

目前多数认为炎症是动脉粥样硬化发生发展的原因和机制。抗炎治疗对防止动脉粥样硬化具有重要意义。胍丁胺是新近发现的内源性物质,能发挥抗平滑肌细胞增殖、抑制脂质过氧化、保护血管内皮功能、降低血糖等作用,显示潜在的抗动脉粥样硬化炎症、防治动脉粥样硬化的作用。     

Assessment of serum leptin,pregnancy-associated plasma protein A and CRP levels as indicators of plaque vulnerability in patients with acute coronary syndrome

Introduction

A multifactorial aetiology of coronary artery disease (CAD) has been established in the recent past. Extensive research is now underway to understand the mechanisms responsible for plaque vulnerability. The identification of a novel biomarker that will help in the assessment of plaque status is urgently needed for the purpose of patient stratification and prognostication. The aim of the present study was to evaluate leptin, pregnancy-associated plasma protein A (PAPP-A) and C-reactive protein (CRP) levels in patients with acute coronary syndrome and to assess their diagnostic efficacy in the identification of vulnerable plaques.

Methods

The study group comprised 105 patients who had chest pain along with ECG changes (ST elevation, ST depression, T inversion) and raised cardiac enzyme levels. Sixty-two patients with chest pain and ECG changes but with normal cardiac enzyme profiles were included in the control group. Lipid profiles, and leptin, PAPP-A and CRP levels were assessed in these two groups. Receiver operating characteristics (ROC) curves were plotted to determine the utility of the parameters under study as markers of plaque vulnerability.

Results

Significantly higher levels of serum lipoprotein (a), leptin, PAPP-A and high-sensitivity CRP (hs-CRP) were observed in the cases than in the controls. A positive correlation was observed between CRP and PAPP-A levels as well as CRP and leptin concentrations. ROC curve analysis revealed similar efficacies of CRP and PAPP-A levels in their ability to detect unstable plaques with areas under the curve of 0.762 and 0.732, respectively. Multivariate analysis established the superiority of hs-CRP as a predictor of plaque instability.

Conclusions

Our study highlights the utility of both CRP and PAPP-A levels as determinants of plaque instability. Our findings necessitate population-based follow-up studies to establish the superiority of either of the two biomarkers in the field of preventive cardiology.     

脂联素与炎症、动脉粥样硬化关系的研究进展

脂联素是脂肪分泌的特异性蛋白质,具有许多内分泌功能,在抑制动脉粥样硬化的发生发展中起着重要作用。血浆脂联素的降低是发生胰岛素抵抗和糖尿病的独立危险因素,对脂联素的深入研究将为2型糖尿病、动脉粥样硬化症及肥胖症等与胰岛素抵抗相关疾病的治疗提供新的思路,为新药的研发提供新的方向。     

Detecting the vulnerable plaque in patients

Atherosclerosis is a systemic condition that eventually evolves into vulnerable plaques and cardiovascular events. Pathology studies reveal that rupture‐prone atherosclerotic plaques have a distinct morphology, namely a thin, inflamed fibrous cap covering a large lipidic and necrotic core. With the fast development of imaging techniques in the last decades, detecting vulnerable plaques thereby identifying individuals at high risk for cardiovascular events has become of major interest. Yet, in current clinical practice, there is no routine use of any vascular imaging modality to assess plaque characteristics as each unique technique has its pros and cons. This review describes the techniques that may evolve into screening tool for the detection of the vulnerable plaque. Finally, it seems that plaque morphology has been changing in the last decades leading to a higher prevalence of ‘stable’ atherosclerotic plaques, possibly due to the implementation of primary prevention strategies or other approaches. Therefore, the nomenclature of vulnerable plaque lesions should be very carefully defined in all studies.     

斑块侵蚀在急性冠状动脉综合征中的作用及机制研究进展

急性冠状动脉综合征是世界范围内发病率和死亡率较高的一组临床综合征。目前,越来越多的证据表明,带有完整纤维帽的斑块侵蚀是导致急性冠状动脉综合征的主要原因之一。基础实验已经揭示了斑块侵蚀的独特分子特征,已有研究表明,血流紊乱会引起内皮细胞损伤,从而导致基底膜丧失其完整性以及内皮细胞脱落,继而形成中性粒细胞胞外陷阱和血栓,导致斑块侵蚀。文章将讨论动脉粥样硬化斑块侵蚀的分子特征以及对斑块侵蚀患者未来精准医疗所需的转化研究。     

动脉粥样硬化易损斑块快速进展机制与临床治疗进展

心血管疾病居我国居民死亡原因首位,动脉粥样硬化(As)是冠心病的主要病理基础。易损斑块是动脉粥样硬化斑块中发展迅速、具有血栓形成倾向的不稳定性高危斑块,快速进展的斑块可引起恶性临床事件,是急性冠状动脉综合征及脑卒中的主要病理机制。现有的As干预策略可以减少30%～45%的急性心肌梗死及脑卒中,但残存风险依然较大。因此深入探究动脉粥样硬化易损斑块快速进展机制及影响因素对预防和治疗心血管事件具有重要的意义。     

多种生化标志物与颈动脉粥样硬化斑块稳定性的关系

目的探讨多种生化标志物与颈动脉粥样硬化斑块稳定性的关系。方法选取经颈动脉彩超检查证实为动脉粥样硬化斑块患者78例,根据超声检查结果分为稳定斑块组42例、不稳定斑块组36例;另选择无斑块的健康体检者42例为对照组。分别测定各组血浆C反应蛋白(CRP)、丙二醛(MDA)、白介素-6(IL-6)、可溶性CD40配体(sCD40L)、纤维蛋白原(FIB)及血脂水平。结果不稳定斑块组血浆CRP、IL-6、sCD40L、MDA水平显著高于稳定斑块组及对照组(P均<0.01),稳定斑块组CRP、IL-6、sCD40L水平显著高于对照组(P均<0.01);不稳定斑块组及稳定斑块组的FIB水平显著高于对照组(P均<0.01)。斑块指数与FIB、sCD40L、IL-6、CRP、MDA水平等呈正相关,其中与sCD40L水平相关性较强(r=0.737,P<0.01)。结论血浆生化标志物CRP、IL-6、MDA、sCD40L水平与斑块的不稳定显著相关,IL-6、MDA、sCD40L有望成为评价斑块稳定性及预测斑块破裂较理想的生化标志物。     

斑块侵蚀的诊疗进展

急性冠状动脉综合征(ACS)是危害人类健康的最严重心血管疾病之一。长期以来,动脉粥样硬化斑块破裂(PR)导致的斑块内容物释放伴随附壁血栓形成被认为是ACS形成的主要机制。随着光学相干断层成像(OCT)的应用,人们认识到除了PR,斑块侵蚀(PE)是ACS的另外一种重要而且常见的病理学机制。近年来对于PE的研究已经取得了一定进展,文章将对PE的诊断以及治疗的研究进展做一综述。     

Evolving Concepts in the Triad of Atherosclerosis,Inflammation and Thrombosis

Recent developments into antherothrombosis, the leading cause of morbidity and mortality in Western Society, may help to change our treatment strategy to a more casual approach. The composition of the atherosclerotic plaque, rather than the percent stenosis, appears to be a critical predictor for both risk of plaque rupture and subsequent thrombogenicity. A large lipid core, rich in tissue factor (TF) and inflammatory cells including macrophages, and a thin fibrous cap with compromise of its structural integrity by matrix degrading enzymes, such as metalloproteinases (MMPs), render a lesion susceptible to rupture and subsequent acute thrombosis. Thrombosis may lead to a complete occlusion or, in the case of mural thrombus or intraplaque hemorrhage, to plaque progression. Disruption of a vulnerable or unstable plaque (type IV and Va lesions of the AHA classification) with a subsequent change in plaque geometry and thrombosis may result in an acute coronary syndrome. The high-risk plaque tend to be relatively small, but soft or vulnerable to "passive" disruption because of high lipid content. Inflammatory processes are important components of all stages of atherosclerotic development, including plaque initiation and disruption. As such the early steps in atherosclerotic lesion formation are the over expression of endothelial adhesive protein (i.e. selectins, VCAM and ICAM), chemotactic factors (MCP-1), growth factors (M-CSF), and cytokines (IL-2) that will facilitate the recruitment, internalization and survival of blood-borne inflammatory cells into the vascular wall. Macrophages, following what appears to be a defense mission by protecting the vessel wall from excess lipid accumulation, may eventually undergo apoptosis with release of MMPs and TF. Specific cell recruitment in the vessel wall and build-up of the extracellular matrix are coordinated by a wide variety of stimulators and inhibitors. Active interaction of immune competent cells within the atherosclerotic lesions appears to play a pivotal role in the control of atherosclerotic plaque evolution and, therefore, deserves particular attention from the research community with the ultimate goal of improving preventive and therapeutic medical approaches. Inflammation, thrombosis and atherosclerosis are interdependent and define a triad within the complex pathogenic process of atherothrombosis.