新生滋养血管在动脉粥样硬化斑块进展中的作用

滋养血管新生作为动脉粥样硬化斑块发生发展中的关键环节已受到普遍关注,在动脉内膜发生缺血缺氧或炎症时可诱发滋养血管新生,并通过白细胞征募和斑块内出血等机制影响斑块的稳定性.     

颈动脉粥样硬化斑块内新生血管的研究现状及进展

颈动脉粥样硬化斑块破裂是导致脑卒中的重要原因之一,大量研究证实颈动脉斑块内新生血管是导致斑块内出血、斑块破裂的重要因素。炎症因子及各类细胞通过斑块内新生血管进入斑块,导致斑块稳定性破坏,但影响斑块内新生血管形成的重要相关因子和主要机制目前尚未完全明确,因此识别斑块内新生血管、探索斑块内新生血管形成的相关因子及机制是研究斑块内新生血管致斑块不稳定性的关键。抑制斑块内新生血管生成,可能成为防治颈动脉斑块破裂、降低脑栓塞事件发生的新策略。本综述旨在探讨颈动脉斑块内新生血管形成的相关因子、机制以及检测成像的最新研究进展,为动脉粥样硬化的诊疗提供支持。     

神经导向因子Netrin-1调节单核巨噬细胞迁移与动脉粥样斑块关系的研究进展

动脉粥样硬化是动脉壁的一种慢性炎症性疾病,单核巨噬细胞在其发生发展中起着关键作用。动脉粥样斑块中单核巨噬细胞迁移能力受损,滞留于斑块内,增加了斑块不稳定性,加速动脉粥样硬化病变的进展。目前研究表明动脉粥样斑块中巨噬细胞分泌的神经导向因子Netrin-1通过与巨噬细胞表面相应受体结合,可以抑制巨噬细胞迁出斑块,促进动脉粥样硬化的进展。但在动脉粥样硬化形成初期,血管内皮细胞表达的Netrin-1却被发现对动脉粥样硬化起到保护作用。     

新生血管形成与动脉粥样硬化

治疗性血管生成通过增加心肌再灌注而提高心功能、降低心肌梗死的发生率,曾被认为是治疗冠心病的新策略。但是,其给斑块的进展和稳定性带来的一些负面的影响也是不容忽视的。近年来,随着人们对斑块与新生血管形成的关系的认识增多,又有了抑制斑块内新生血管生成而抑制斑块进展和增加斑块稳定性的治疗理念。本文将综述新生血管与动脉粥样硬化斑块稳定性的关系以及抑制新生血管形成的治疗进展。     

动脉粥样硬化斑块内血管新生的研究进展

动脉粥样硬化是诱导心脑血管相关疾病发生的主要原因,在动脉粥样硬化的影响因素中,血管新生是导致斑块内破裂并引发各种并发症的主要原因之一。缺氧、炎症、生长因子相关因素可引发斑块内血管新生,导致动脉粥样硬化的发生。本文对影响血管新生的相关因素及其作用机制作一综述,为动脉粥样硬化的防治提供新的思路和干预靶点。     

超声造影评价颈动脉斑块内新生血管的研究进展

动脉粥样硬化斑块与心脑血管事件的发生密切相关,早期评估动脉粥样硬化斑块的稳定性对于预防心脑血管事件发生及制定治疗方案十分重要。大量研究证实斑块内新生血管与斑块的稳定性有关,超声造影可显示和评估颈动脉斑块内新生血管,是近年来斑块稳定性研究的热点技术之一。     

斑块内新生血管的作用及应对

斑块内新生血管是由内皮细胞芽生形成.动脉粥样硬化相关的生理性新生血管能改善动脉壁供氧状态,减轻炎症反应,逆转动脉粥样硬化的进展.病理性新生血管则会加速疾病的进程,增加巨噬细胞浸润和血管壁的厚度,导致持续的缺氧状态,甚至坏死.此外,新生血管壁的破裂可以导致斑块内出血、增强炎性反应、扩大脂质核心、激发氧化应激反应和斑块破裂.     

动脉粥样硬化斑块滋养血管研究

研究表明,动脉粥样硬化斑块滋养血管在促进斑块的进展、不稳定斑块的形成、斑块内出血甚至破裂方面有着不可忽视的作用。随着对不同阶段斑块滋养血管新生机制研究的进一步深入,针对其进行有效的干预进而达到延缓斑块进展、增加斑块稳定性的目的也将成为可能,这或许能够为临床治疗动脉粥样硬化疾病提供新的策略和理念。     

CD105在动脉粥样硬化血管新生中的研究进展

近年研究发现,在动脉粥样硬化斑块内常常出现病理性新生血管,可促进斑块的发生发展,甚至诱发斑块出血和斑块破裂,是促进稳定型斑块向不稳定型斑块发展的重要机制。如何早期识别易损斑块一直是临床工作的重点和难点。CD105是一种内皮细胞表达的糖蛋白,属于转化生长因子-β（transforminggrowthfactor—beta,TGF-β）超家族成员之一,是最近多数学者确定的一种最理想的人类内皮细胞增殖的指示剂。本文就CD105的分子结构和功能、CDl05与血管新生的关系、抑制血管新生在动脉粥样硬化治疗中的意义及进展进行综述。     

心外膜脂肪因子促进血管新生的分子机制

心外膜脂肪组织是沉积在心脏尤其是冠状动脉周围的脂肪组织，可以表达多种脂肪因子参与动脉粥样硬化的发生与发展，最近这些脂肪因子已经被证实还可以引起冠状动脉粥样硬化斑块内的血管新生。这些新生血管在斑块内可能具有双重效应：一方面，新生血管具有很强的通透性，可以改善斑块局部缺氧状况；另一方面，新生血管可能促进斑块进展并导致其不稳定性增加。因此，通过研究脂肪因子致血管新生作用的机制，抑制斑块内的血管新生增强其稳定性可能成为未来治疗冠心病新的靶点。     

Plaque neovascularization and antiangiogenic therapy for atherosclerosis.

The concept that neovascularization of the vessel wall may play a fundamental role in the pathophysiology of atherosclerosis was proposed more than a century ago. In recent years, supportive experimental evidence for this hypothesis (such as the finding that neointimal microvessels may increase delivery of cellular and soluble lesion components to the vessel wall) has been underscored by clinical studies associating plaque angiogenesis with more rapidly progressive high-grade disease. Attention has also focused on a possible role for microvessel-derived intraplaque hemorrhage in the development of acute lesion instability. The interest of clinicians in this phenomenon has been spurred by the potential to target vessel wall neovascularization with angiogenesis inhibitors, a therapeutic approach that has been associated with impressive reductions in plaque progression in animal models of vascular disease. The rationale for pursuing an "antiangiogenic" strategy in the treatment of patients with vascular disease, and a framework for further preclinical evaluation of such therapy, is presented here.     

Plaque neovascularization and antiangiogenic therapy for atherosclerosis

The concept that neovascularization of the vessel wall may play a fundamental role in the pathophysiology of atherosclerosis was proposed more than a century ago. In recent years, supportive experimental evidence for this hypothesis (such as the finding that neointimal microvessels may increase delivery of cellular and soluble lesion components to the vessel wall) has been underscored by clinical studies associating plaque angiogenesis with more rapidly progressive high-grade disease. Attention has also focused on a possible role for microvessel-derived intraplaque hemorrhage in the development of acute lesion instability. The interest of clinicians in this phenomenon has been spurred by the potential to target vessel wall neovascularization with angiogenesis inhibitors, a therapeutic approach that has been associated with impressive reductions in plaque progression in animal models of vascular disease. The rationale for pursuing an "antiangiogenic" strategy in the treatment of patients with vascular disease, and a framework for further preclinical evaluation of such therapy, is presented here.     

Inhibition of plaque neovascularization reduces macrophage accumulation and progression of advanced atherosclerosis

Plaque angiogenesis promotes the growth of atheromas, but the functions of plaque capillaries are not fully determined. Neovascularization may act as a conduit for the entry of leukocytes into sites of chronic inflammation. We observe vasa vasorum density correlates highly with the extent of inflammatory cells, not the size of atheromas in apolipoprotein E-deficient mice. We show atherosclerotic aortas contain activities that promote angiogenesis. The angiogenesis inhibitor angiostatin reduces plaque angiogenesis and inhibits atherosclerosis. Macrophages in the plaque and around vasa vasorum are reduced, but we detect no direct effect of angiostatin on monocytes. After angiogenesis blockade in vivo, the angiogenic potential of atherosclerotic tissue is suppressed. Activated macrophages stimulate angiogenesis that can further recruit inflammatory cells and more angiogenesis. Our findings demonstrate that late-stage inhibition of angiogenesis can interrupt this positive feedback cycle. Inhibition of plaque angiogenesis and the secondary reduction of macrophages may have beneficial effects on plaque stability.     

Role of angiogenesis in cardiovascular disease: a critical appraisal

The role of angiogenesis in atherosclerosis and other cardiovascular diseases has emerged as a major unresolved issue. Angiogenesis has attracted interest from opposite perspectives. Angiogenic cytokine therapy has been widely regarded as an attractive approach both for treating ischemic heart disease and for enhancing arterioprotective functions of the endothelium; conversely, a variety of studies suggest that neovascularization contributes to the growth of atherosclerotic lesions and is a key factor in plaque destabilization leading to rupture. Here, we critically review the evidence supporting a role for angiogenesis and angiogenic factors in atherosclerosis and neointima formation, emphasizing the problems raised by some of the landmark studies and the suitability of animal models of atherosclerosis and neointimal thickening for investigating the role of angiogenesis. Because many of the relevant studies have focused on the role of vascular endothelial growth factor (VEGF), we consider this work in the wider context of VEGF biology and in light of recent experience from clinical trials of VEGF and other angiogenic cytokines for ischemic heart disease. Also discussed are recent findings suggesting that, although angiogenesis may contribute to neointimal growth, it is not required for the initiation of intimal thickening. Our assessment of the evidence leads us to conclude that, although microvessels are a feature of advanced human atherosclerotic plaques, it remains unclear whether angiogenesis either plays a central role in the development of atherosclerosis or is responsible for plaque instability. Furthermore, current evidence from clinical trials of both proangiogenic and antiangiogenic therapies does not suggest that inhibition of angiogenesis is likely to be a viable therapeutic strategy for cardiovascular disease.     

Imaging of the vasa vasorum

Neovascularization of the arterial walls by adventitial vasa vasorum appears to participate in the process of atherosclerosis progression and destabilization. Although the biological mechanisms associated with plaque instability are still unclear, the uncontrolled formation of intraplaque neovessels appears to contribute to the development of complex atheromatous lesions. Recent reports have described the use of several ultrasound-based techniques for the real-time detection of intraplaque neovascularization. Preliminary studies in animal models have shown that the detection and characterization of adventitial neovascularization are technically feasible. The further development of these imaging techniques relies on the successful implementation of contrast microspheres capable of enhancing microvascular structures. These contrast agents serve as surrogate red blood cells and perform acoustically as true intravascular tracers providing, in real-time, the amount and distribution of neovessels within atherosclerotic lesions. Several ultrasound-based techniques are under development for the detection of adventitial vasa vasorum in the carotid and coronary vascular territories. Although still in early validation phases, these techniques might permit the early diagnosis and stratification of subclinical atherosclerosis, thus permitting aggressive preventive therapy. In the near future, innovative contrast agents using specific ligands are likely to expand the diagnostic and therapeutic possibilities of these emerging imaging techniques.     

New strategy of antiangiogenic therapy for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a hypervascular tumor, and tumor progression and prognosis is associated with angiogenesis. Extracellular matrix remodeling and inflammation play important roles in hepatocarcinogenesis. Some ingredients of extracellular matrix such as endostatin and sulfated polysaccharide, some immunomodulatory agents and cox-2 inhibitor suppress the angiogenesis of HCC. Because vasculogenic mimicry is associated with high tumor grade, some differentiation agents are used to inhibit antiagiogenesis. Besides suppressing the proliferation directly, somatostatin inhibits angiogenesis to suppress growth indirectly. Copper chelator prevents copper from functioning as a cofactor in angiogenesis. The renin-angiotensin system is frequently activated in patients with chronic liver diseases. Perindopril, an angiotensin converting enzyme inhibitor, inhibits angiogenesis by reducing vascular endothelial growth factor (VEGF) production. Kinase inhibitors of VEGF and epidermal growth factor receptors are expected to be of benefit for some patients. Following transarterial embolisation and/or resection, antiangiogenic therapy could prevent the recurring and metastasis. Hypoxia enhances the proliferation, suppresses the differentiation and apoptosis, and induces multidrug resistance of HCC. Because antiangiogenic therapies induce hypoxia, it should be borne in mind the side affects of antiangiogenic therapy. Because long-acting antiangiogenent are needed to control cancer, it needs more clinical studies to confirm the drug resistance of antiangiogenetic therapy.     

内脂素与动脉粥样硬化性相关疾病

目的 内脂素是新近发现的由内脏脂肪细胞高表达的一种脂肪细胞因子,具有类胰岛素作用.近年来的许多研究表明,内脂素与缺氧、易损斑块破裂、内皮功能紊乱、血管增生、炎症和糖脂代谢等密切相关,与动脉粥样硬化的发生和发展过程密切相关.内脂素的发现为研究动脉粥样硬化性相关疾病的发病机制增加了新的思路,为动脉粥样硬化性相关疾病的防治提供了一个新的靶点.