巨噬细胞及其亚型在动脉粥样硬化中的研究进展

巨噬细胞和动脉粥样硬化的发生、发展密切相关，分布在粥样斑块中的巨噬细胞又可分为M1、M2等不同亚型。不同亚型的巨噬细胞具有不同、甚至是相反的生理功能，其对动脉粥样硬化的病程也有不同的影响。因此利用药物以调控动脉粥样斑块内巨噬细胞不同亚型的分化为靶点干预病程进展可能是一种潜在的有效治疗措施。     

单核-巨噬细胞与缺血性心脏病:心梗引起心梗？

急性冠脉综合征后发生死亡、再梗及卒中等后续不良事件风险增加是缺血性心脏病的研究热点。单核-巨噬细胞广泛参与动脉粥样硬化斑块形成、破裂及心肌缺血损伤、修复。心肌梗死(MI)后交感神经激活,骨髓和脾脏造血作用增强,导致循环中炎性单核细胞激增,改变斑块中巨噬细胞的表型及供应链,从而加速动脉粥样斑块的发展,可能导致再梗或再缺血的发生。本文将对MI如何通过单核-巨噬细胞途径加重动脉粥样硬化进行综述。     

动脉粥样硬化进程中单核/巨噬细胞的行为变化

动脉粥样硬化是由脂质引发的炎症性疾病,单核/巨噬细胞在动脉粥样硬化发生发展过程中发挥极其重要的作用。巨噬细胞吞噬脂质后成为泡沫细胞,构成动脉粥样硬化的脂质条纹和粥样斑块。过去几年中,对于单核细胞如何聚集、分化、摄取脂质及其在动脉粥样硬化中的作用有了进一步了解。单核/巨噬细胞表型和功能的复杂性提示其很可能会成为动脉粥样硬化治疗的靶点。本文就单核/巨噬细胞在动脉粥样硬化进程中的行为变化进行综述。     

脂蛋白相关磷脂酶A2:一种独立血管风险预测因子和治疗新靶点

脂蛋白相关磷脂酶A2(lipoprotein-associated phospholipase A2,Lp-PLA2)可快速水解氧化低密度脂蛋白和脂蛋白(a)中的氧化磷脂分子,生成可溶性促炎和促凋亡介质-溶血卵磷脂和氧化游离脂肪酸,刺激单核巨噬细胞系统聚集和激活,诱导细胞凋亡和破坏死亡细胞的清除,在动脉粥样硬化脂质坏死核心的发展中起重要作用.Lp-PLA2不仅是冠状动脉疾病和缺血性卒中的独立风险标志物,而且在动脉粥样硬化斑块进展中起重要作用.选择性Lp-PLA2抑制剂可减少坏死核心的发展,可能对动脉粥样斑块起稳定作用,同时可能代表着一种动脉粥样硬化的治疗新靶点.     

脂蛋白相关磷脂酶A2:一种独立血管风险预测因子和治疗新靶点

脂蛋白相关磷脂酶A2(lipoprotein-associated phospholipase A2,Lp-PLA2)可快速水解氧化低密度脂蛋白和脂蛋白(a)中的氧化磷脂分子,生成可溶性促炎和促凋亡介质-溶血卵磷脂和氧化游离脂肪酸,刺激单核巨噬细胞系统聚集和激活,诱导细胞凋亡和破坏死亡细胞的清除,在动脉粥样硬化脂质坏死核心的发展中起重要作用.Lp-PLA2不仅是冠状动脉疾病和缺血性卒中的独立风险标志物,而且在动脉粥样硬化斑块进展中起重要作用.选择性Lp-PLA2抑制剂可减少坏死核心的发展,可能对动脉粥样斑块起稳定作用,同时可能代表着一种动脉粥样硬化的治疗新靶点.     

动脉粥样硬化与免疫

动脉粥样硬化是一种脂质驱动的慢性炎症性疾病,表现为富含载脂蛋白B的脂蛋白、免疫细胞以及细胞外基质在动脉内皮下积聚形成粥样斑块。修饰后的脂蛋白获得损伤相关分子模式特征,首先触发以单核-巨噬细胞为主的固有免疫反应,其次是获得性免疫反应。这些炎症反应通常是慢性的且无法消除,并可能导致动脉损伤以及血栓诱发的器官梗死。本文主要综述免疫系统在动脉粥样硬化发生发展过程中的作用以及目前动脉粥样硬化的主要免疫防治策略。     

从炎症反应到动脉粥样硬化

近年来许多学者已认识到动脉粥样硬化 (以下简称动脉硬化 )的发生和发展过程中 ,慢性炎症反应是一个极为重要的因素[1,2 ] 。除已知的促动脉硬化的危险因素如遗传基础、高血压、糖尿病、高血脂 [尤其是氧化低密度脂蛋白 (oxLDL)的升高 ]、高同型半胱氨酸血症、抽烟、压力、某些感染外 ,现认为炎症反应、内皮细胞功能异常是参与动脉硬化发展的潜在因素。在动脉硬化的粥样斑块中看到单核 /巨噬细胞和不同亚型的淋巴细胞 ,且其数量随疾病发展而增长。Schonbeck等[3] 在动脉壁正常组织中只能测到环氧酶 (COX ) 1,但在动脉粥样斑块组织中除C…     

从目前的临床试验看维生素E对心血管病的二级预防作用

大量实验证实低密度脂蛋白 (LDL)氧化在动脉粥样硬化的启动和进展中起着重要作用[1,2 ] 。例如 :培养的动脉血管壁细胞发生LDL氧化 ,可被巨噬细胞清道夫受体识别 ;从人和动物动脉粥样斑块分离的LDL有明显的氧化损害的证据 ;脂质氧化产物抗体可检测出动脉粥样硬化损害处的抗原决定簇 ,表明动脉壁存在氧化型低密度脂蛋白 (oxLDL) ,有力地支持LDL脂质和 (或 )蛋白的氧化对动脉粥样硬化的形成起着重要作用。从理论上讲 ,抗氧化剂可降低自由基水平 ,防止LDL过氧化 ,从而减少发生动脉粥样硬化的危险 ,延缓其进展 ,甚至逆转已形成的粥样斑…     

CD40系统与动脉粥样硬化研究的新进展

越来越多的研究证实动脉粥样硬化是一种炎症发应,CD40系统的相互作用是炎症信号的重要传导通路,还参与粥样斑块内重要细胞如血管内皮细胞、血管平滑肌细胞及巨噬细胞等的炎症反应调节。阻断CD40CD40配体之间的相互作用可以抑制动脉粥样斑块的发生发展。最进,动脉粥样硬化(Atherosclerosis,AS)发病机制的研究有了很大进展,以前AS仅仅被认为是脂质堆积造成显著管腔狭窄或闭合。现在许多研究都证实AS是一种多种免疫因素参与的慢性炎症性疾病[1]。炎症发应贯穿于AS的发生、发展、变化的全过程,并在很大程度上决定着动脉粥样斑块的稳定性[2…     

糖代谢紊乱与动脉粥样硬化

糖代谢紊乱为动脉粥样硬化的危险因素之一.研究表明:高血糖可直接作用于血管细胞,如血管内皮细胞、血管平滑肌细胞及血管炎症细胞等;另一方面,高血糖可导致相关基因发生化学修饰,上调基因的表达而促进单核巨噬细胞向泡沫细胞转化,作用于相应基因靶点促进巨噬细胞活化及动脉粥样斑块的形成.因此,血糖可能通过上述一种或多种作用机制促进动...     

Pro-inflammatory activities induced by CyPA-EMMPRIN interaction in monocytes

Excessive reactive oxygen species (ROS) is a critical driver of vascular inflammation in atherosclerosis. Cyclophilin A (CyPA) is the main ROS-induced factor that enhances the inflammatory activity of monocytes/macrophages in atherosclerotic plaque. However, the means by which CyPA interacts with monocytes/macrophages is unclear. Through Chemotaxis assay and ELISA test, we found CyPA strongly induced migration of monocytes and the expression of mmp-9, IL-6 and TNF-alpha. By Western blot, it demonstrated that CyPA activated NF-kappaB by ERK1/2 pathway. When blocking extracellular matrix metalloproteinase inducer (EMMPRIN) in monocytes, most of the CyPA effects including chemoattractant migration, activation of MAPK/NF-kappaB and cytokines releasing were significantly inhibited. Finally, CyPA simulation had no effect on EMMPRIN expression in monocytes. The current study shows that CyPA-EMMPRIN interaction is one of the key pro-inflammatory signaling pathways in monocytes, perhaps especially in response to ROS stimulation. This could be a potential target for atherosclerosis therapy.     

Low molecular weight hyaluronan increases the Uptaking of oxidized LDL into monocytes

Since accumulation and interaction of immune cells including T cells and monocytes/macrophages are involved in the processes of atherosclerosis, atherosclerosis is currently understood as an inflammatory disorder. Entrapment of extracellular matrices components such as hyaluronan by monocytes and macrophages, as well as uptake of oxidized low-density lipoprotein (ox-LDL) by these cells, plays a central role in foam cell formation and the pathogenesis of atherosclerosis. We investigated the role of CD44, the principal receptor for hyaluronic acid, and ox-LDL in scavenger receptor expression on resting monocytes prepared by counterflow centrifugal elutriation from the endothelium. Our results showed that the low-molecular weight (6.9 kDa) form of hyaluronan increased the expression of CD36 scavenger receptor; the incorporation of (125) I-labeled ox-LDL, and the transendothelial migration of monocytes, which were mediated at least in part via tyrosine kinase and the PKC pathway. Our results imply that low molecular weight hyaluronan produced in large amounts in atherosclerotic lesions induces differentiation of circulating monocytes to macrophages/foam cells and enhances the progression of atherosclerosis via the PKC pathway. Furthermore, low molecular weight hyaluronan also amplifies the migration of monocytes into inflamed atherosclerotic plaques. Thus, we propose that engagement of CD44 with low molecular weight hyaluronan is centrally involved in the inflammatory pathogenesis of athelosclerotic plaques through migration of monocytes and foamed macrophage differentiation.     

基于单细胞转录组鉴定动脉粥样硬化自身免疫表征

目的]基于单细胞转录组生物信息学方法探讨动脉粥样硬化免疫微环境特征,挖掘免疫炎症与动脉粥样硬化之间潜在的联系。 [方法]从GEO数据库中提取单细胞转录组数据集GSE159677,可视化分析颈动脉粥样硬化斑块区及其近心端毗邻非斑块区细胞组成成分,利用CellChat整合细胞间通讯网络,分析细胞间交互作用差异,识别动脉粥样硬化斑块免疫炎症信号通路差异,探索动脉粥样硬化免疫微环境中细胞间受体-配体特异性变化通路。 [结果]本研究从单细胞测序的视角分析了动脉粥样硬化斑块内的细胞构成和细胞通讯。研究发现,在动脉粥样硬化斑块的细胞构成中内皮细胞和平滑肌细胞减少,而T细胞、单核细胞、巨噬细胞及软骨细胞明显增加。通过细胞通讯分析,发现树突状细胞、单核细胞、巨噬细胞、自然杀伤细胞与内皮细胞间的通讯作用及部分细胞与单核细胞间的通讯作用均有显著的改变,相关信号通路包括CXCL家族与ACRK1、CCL家族与ACRK1、MIF与CD74等配体-受体互作。MIF、ANXA1、YNF、RETN、LGASL9等对单核细胞以及NAMPT、CCL2、TNFSF12对内皮细胞的通讯改变在免疫炎症反应调控动脉粥样硬化机制中起着关键作用。 [结论]免疫炎症微环境在动脉粥样硬化斑块形成过程中发挥了重要调控作用。     

Increased levels of the homeostatic chemokine CXCL13 in human atherosclerosis - Potential role in plaque stabilization

ObjectivesBased on the newly recognized role of the homeostatic chemokines in inflammation, we hypothesized that CXCL13 could modulate atherogenesis and plaque destabilization.MethodsThe study included in vivo analyses in patients with carotid atherosclerosis and in vitro experiments in cells involved in atherogenesis (ie, monocytes/macrophages, vascular smooth muscle cells [SMC], and platelets).ResultsOur main findings were: (i) Patients with carotid atherosclerosis (n = 130) had increased plasma levels of CXCL13 with particularly high levels in symptomatic disease. (ii) CXCL13 showed increased expression within atherosclerotic carotid plaques as compared with non-atherosclerotic vessels. (iii) Within the atherosclerotic lesions, CXCR5 and CXCL13 were expressed by macrophages and SMC in all stages of plaque progression. (iv) Releasate from activated platelets and toll-like receptor activation enhanced the expression of CXCL13 in THP-1 monocytes and primary monocytes. (v) In vitro, CXCL13 exerted anti-apoptotic effects in primary monocytes, THP-1 macrophages, and vascular SMC. (vi) CXCL13 increased arginase-1, transforming growth factor-β, and interleukin-10 expression in THP-1 cells and in samples from isolated carotid plaques.ConclusionLevels of CXCL13 are increased in carotid atherosclerosis both systemically and within the atherosclerotic lesion. Based on our in vitro findings, we hypothesize a potential plaque stabilizing effects of CXCL13-CXCR5 interaction.     

组织因子与冠心病

组织因子作为因子 F /F a的细胞膜表面受体 ,是生理凝血过程中最重要的启动因子 ,许多炎性介质能诱导单核细胞、巨噬细胞、平滑肌细胞和血管内皮细胞表达组织因子。组织因子通过介导凝血激活形成血栓以及促进平滑肌细胞增殖和移行影响冠心病的发生和发展。本文对组织因子与动脉粥样硬化、血管成形术后再狭窄 ,心肌缺血及心肌缺血 -再灌注损伤等冠心病相关病理过程作一综述     

Monocyte/macrophage suppression in CD11b diphtheria toxin receptor transgenic mice differentially affects atherogenesis and established plaques

Although monocytes/macrophages are considered important in atherogenesis, their role in established plaques is unclear. For example, macrophage content is associated with plaque instability, but their loss through cell death is observed at sites of plaque rupture. To examine the role of monocytes/macrophages in atherosclerosis, we developed CD11b-diphtheria toxin (DT) receptor (DTR) transgenic mice, whereby administration of DT selectively kills monocytes/macrophages. DT treatment reduced peripheral blood monocytes and tissue macrophages and inhibited macrophage function in CD11b-DTR mice and apolipoprotein E-null (apoE(-/-)) mice transplanted with CD11b-DTR bone marrow. In atherogenesis experiments, DT markedly reduced plaque development and altered plaque composition, reducing collagen content and necrotic core formation. In mice with established plaques, acute DT treatment induced macrophage apoptosis and reduced macrophage content but did not induce plaque inflammation, thrombosis, or rupture. Furthermore, despite a 50% reduction in monocytes, chronic DT treatment of these mice did not alter plaque extent or composition, most likely because of ongoing recruitment/proliferation of monocytes with recovery of macrophage content. We conclude that monocytes/macrophages are critical to atherogenesis, but established plaques are more resistant to reductions in monocytes.     

Macrophages, inflammation, and atherosclerosis

The macrophage plays a diverse array of roles in atherogenesis and lipoprotein metabolism. The macrophage functions as a scavenger cell, an immune mediator cell, and as a source of chemotactic molecules and cytokines. Chemokines have been implicated in promoting migration of monocytes into the arterial intima. Monocyte chemoattractant protein-1 (MCP-1) attracts monocytes bearing the chemokine receptor CCR-2. Macrophage expression of cyclooxygenase-2, a key enzyme in inflammation, promotes atherosclerotic lesion formation in low-density lipoprotein receptor (LDLR)-deficient mice. In the arterial intima, monocytes differentiate into macrophages, which accumulate cholesterol esters to form lipid-laden foam cells. Foam cell formation can be viewed as an imbalance in cholesterol homeostasis. The uptake of atherogenic lipoproteins is mediated by scavenger receptors, including SR-A and CD36. In the macrophage, ACAT-1 is responsible for esterifying free cholesterol with fatty acids to form cholesterol esters. Surprisingly, deficiency of macrophage ACAT-1 promotes atherosclerosis in LDLR-deficient mice. A number of proteins have been implicated in the process of promoting the efflux of free cholesterol from the macrophage, including apoE, ABCA1, and SRB-1. Macrophage-derived foam cells express the adipocyte fatty acid-binding protein (FABP), aP2, a cytoplasmic FABP that plays an important role in regulating systemic insulin resistance in the setting of obesity. ApoE-deficient mice null for macrophage aP2 expression develop significantly less atherosclerosis than controls wild type for macrophage aP2 expression. These results demonstrate a significant role for macrophage aP2 in the formation of atherosclerotic lesions independent of its role in systemic glucose and lipid metabolism. Furthermore, macrophages deficient in aP2 display alterations in inflammatory cytokine production. Through its distinct actions in adipocytes and macrophages, aP2 links features of the metabolic syndrome including insulin resistance, obesity, inflammation, and atherosclerosis.     

Human cytomegalovirus infection and atherothrombosis

Vascular endothelium, as a key regulator of hemostasis, mediates vascular dilatation, prevents platelet adhesion, and inhibits thrombin generation. Endothelial dysfunction caused by acute or chronic inflammation, such as in atherosclerosis, creates a proinflammatory environment which supports leukocyte transmigration toward inflammatory sites, and at the same time promotes coagulation, thrombin generation, and fibrin deposition in an attempt to close the wound. Life-long persistent infection with human cytomegalovirus (HCMV) has been associated with atherosclerosis. In vivo studies have revealed that HCMV infection of the vessel wall affects various cells including monocytes/macrophages, smooth muscle cells (SMCs) and endothelial cells (ECs). HCMV-infected SMCs within vascular lesions display enhanced proliferation and impaired apoptosis, which contribute to intima-media thickening, plaque formation and restenosis. Monocytes play a central role in the process of viral dissemination, whereas ECs may represent a viral reservoir, maintaining persistent infection in HCMV-infected atherosclerotic patients following the primary infection. Persistent infection leads to dysfunction of ECs and activates proinflammatory signaling involving nuclear factor κB, specificity protein 1, and phosphatidylinositol 3-kinase, as well as expression of platelet-derived growth factor receptor. Activation of these pathways promotes enhanced proliferation and migration of monocytes and SMCs into the intima of the vascular wall as well as lipid accumulation and expansion of the atherosclerotic lesion. Moreover, HCMV infection induces enhanced expression of endothelial adhesion molecules and modifies the proteolytic balance in monocytes and macrophages. As a consequence, infected endothelium recruits naive monocytes from the blood stream, and the concomitant interaction between infected ECs and monocytes enables virus transfer to migrating monocytes. Endothelial damage promotes thrombin generation linking inflammation and coagulation. HCMV, in turn, enhances the thrombin generation. The virus carries on its surface the molecular machinery necessary to initiate thrombin generation, and in addition, may interact with the prothrombinase protein complex thereby facilitating thrombin generation. Thus, infection of endothelium may significantly increase the production of thrombin. This might not only contribute to thrombosis in patients with atherosclerosis, but might also induce thrombin-dependent proinflammatory cell activation. This review summarizes the existing evidence on the role of HCMV in vascular inflammation.     

Apoptosis of human macrophages by Flt-4 signaling: implications for atherosclerotic plaque pathology

BACKGROUND: Neointimal inflammation and angiogenesis are important contributors of progression and destabilization of the atherosclerotic plaque. While the role of vascular endothelial growth factor (VEGF) and its receptors VEGF-R1 (Flt-1) and VEGF-R2 (Flk-1) in this process has clearly been defined, expression of the VEGF-R3 (Flt-4) has only been documented on lymphatic and tumor endothelium. This study examined Flt-4 expression in human atherosclerotic plaque and explored its implications for atherosclerotic disease. METHODS AND RESULTS: Carotid artery thrombendartherectomy specimens from 10 patients with unstable plaque were stained for Flt-4 and its specific growth factors VEGF-C and VEGF-D. Microvascular endothelial cells (MVEC) stained positive for VEGF-C and -D, but not for Flt-4. Interestingly, macrophages within inflammatory perivascular regions coexpressed Flt-4, VEGF-C and VEGF-D. In vitro studies confirmed the expression of Flt-4, VEGF-C and VEGF-D in human monocytes and cultured macrophages. Treatment of macrophages with VEGF-D induced apoptosis as determined by annexin V staining, by immunoblotting of activated caspase 3, and by the ratio of Bcl-2/Bax as well as by DNA fragmentation. Immunohistochemical studies of advanced human carotid atherosclerotic plaque confirmed the coexpression of Flt-4 with activated caspase 3 and TUNEL staining in macrophages, indicating an ongoing apoptotic process. CONCLUSION: Human monocytes/macrophages express VEGF-C and -D and their receptor Flt-4 in vitro and in vivo within advanced atherosclerotic lesions. Flt-4, in turn, mediates monocyte/macrophage apoptosis and may this way alter plaque stability.     

Oxidized low density lipoprotein induces differentiation and adhesion of human monocytes and the monocytic cell line U937.

Hypercholesterolemia is a major risk factor for development of atherosclerosis. In experimental animals fed a high-cholesterol diet, monocytes adhere to the arterial endothelium and penetrate into the intima where they differentiate into macrophages and ingest lipids thus giving rise to fatty streaks, the earliest type of atherosclerotic plaque. Macrophages express few receptors for normal low density lipoprotein (LDL) but can take up oxidized LDL by way of a scavenger receptor. The present study was designed to investigate the possible role of oxidized LDL in recruitment of resident intimal macrophages. We found that oxidized LDL induced enhanced expression of major histocompatibility complex class II molecules on human monocytes and U937 cells, a well-established system for studies of monocytic differentiation. Oxidized LDL also induced enhanced expression of the surface antigen LeuM3 but caused decreased expression of CD4 antigen, a pattern compatible with expression of a more-differentiated macrophage-like phenotype. Oxidized LDL also initiated aggregation of monocytes and U937 cells and stimulated adhesion of U937 cells to cultured endothelial cells. The results indicate that oxidized LDL may contribute to development of atherosclerosis by inducing adhesion of monocytes to the arterial intima and by stimulating intimal monocytes to differentiate into resident macrophages.