血管钙化发病的新假说--血管破骨细胞样细胞

血管钙化是动脉粥样硬化的一个显著特征 ,是心血管疾病致残、致死的主要原因。目前研究认为 ,血管钙化不是钙盐在血管组织的被动沉积 ,而是类似骨形成和骨质疏松发生的主动的调节过程。血管平滑肌细胞由肌细胞表型转变为成骨细胞表型 ,是血管钙化的细胞学基础。但最近ＤｏｈｅｒｔｙＴＭ等提出了一个新假说 ,他们认为在血管中存在与骨组织相似的调节钙盐代谢的机制 ,成骨样细胞调节血管钙沉积 ,而调节血管钙吸收功能则由单核巨噬细胞系的前体衍生而来的破骨细胞样细胞 (ＯＬＣｓ)执行。动脉粥样硬化中钙沉积是由于成骨样细胞所致的钙沉积与…     

细胞外基质、基质水解酶与血管钙化

血管钙化常见于动脉粥样硬化、糖尿病、慢性肾功能衰竭及衰老的血管.近年来的研究证实血管钙化的发生是一种类似于生理性矿化的主动调节过程,而非单纯的钙磷的被动沉积.血管细胞外基质是血管的主要组成成分,对血管起支持、保护作用,且与血管壁细胞相互作用影响其粘附、增殖、迁移、分化等功能,同时又是各种生长因子和细胞因子的储存库.目前的研究显示,在血管钙化过程中细胞外基质的组成和表达可能发生了变化,并参与了对钙化进程的主动调节.基质水解酶可能通过基质降解依赖或非依赖的机制,在钙化的发生发展中起到重要作用.本文主要综述了在血管钙化过程中细胞外基质的变化及其对血管钙化的作用,以及基质水解酶对血管钙化过程可能的影响.     

巨噬细胞源性破骨细胞在血管钙化中的作用

血管钙化是一种细胞介导的主动生物学过程，类似于骨重塑，在急慢性心脑血管事件的发生与演进过程中发挥了重要的推动作用。近年来有关血管钙化的机制与防治研究逐渐受到广大学者的关注，但遗憾的是，精准的分子与细胞靶向治疗尤其是能在临床推广应用的成果却罕有出现。新近的研究显示，糖尿病动脉粥样硬化斑块中存在成骨细胞表型和功能失调的破骨细胞表型，成骨细胞与破骨细胞调控的失衡可能是动脉粥样硬化斑块内钙化形成的关键环节。已知由巨噬细胞分化而来的破骨细胞是机体内唯一有骨吸收特性的细胞，具备促钙化消退的潜能。因此，探索促斑块内巨噬细胞源性破骨细胞骨吸收活性的研究是一个有望为钙化防治带来新突破的方向。然而，目前关于破骨细胞在血管钙化中的作用和相关调控机制仍存在争议。基于该领域的研究进展和本课题组的实验结果，本文凝练出了羧甲基赖氨酸（CML）通过STAT3调控NFATc1-GNPTAB信号介导斑块内巨噬细胞破骨化吸收障碍的假说，并从血管钙化的概念与机制、破骨细胞与血管钙化间的关系、血管钙化中破骨细胞的调控机制以及破骨细胞作为血管钙化治疗靶点4个方面进行简要阐述，希望为后续血管钙化的精准防治提供新的切入点。     

冠状动脉钙化及相关中草药的作用

动脉钙化（AC）,尤其是属于动脉内膜钙化的冠状动脉钙化（CAC）,是动脉粥样硬化过程中的一种病理现象。最初,CAC是减轻动脉粥样硬化炎症的一种自我保护机制。但是,它也是造成动脉粥样硬化斑块破裂的重要原因。尤其是CAC早期的微钙化,这是斑块破裂的主要原因。从早期的微钙化到后期动脉钙化的稳定融合,不同程度的CAC对心血管事件有不同影响。数百年来,中草药（CHM）一直被用于治疗动脉粥样硬化性心血管疾病。CHM如何有效治疗CAC及其病理机制有待进一步研究。本文回顾了CAC发生的分子机制以及CHM对这些病理过程的影响。     

动脉钙化发生机制研究进展

动脉钙化是指钙盐沉积在动脉壁组织的一种病理改变,会减少主动脉和支动脉的弹性,改变心血管系统的血液流动力学,导致高血压、主动脉瓣狭窄、心脏肥厚、心肌和下肢缺血、充血性心力衰竭等严重心脑血管疾病发生。动脉钙化在老年人群中是一种常见的疾病。早期研究发现尿毒症患者体内磷酸钙沉积的抑制剂——焦磷酸盐水平升高,故有学者认为钙磷被动地沉积于血管壁是引起血管钙化的主要原因。近年来的研究发现,血管钙化并非简单地由于磷酸钙晶体被动地沉积于血管壁,而是一个与骨发育相似的主动的、可预防和可逆转的高度可调控的生物学过程。动脉钙化的发生受多因素共同调控,但其确切机制尚不清楚,最近发现炎症小体也以某种未知的机制参与钙化调控过程。     

自噬与动脉粥样硬化关系的研究进展

自噬是将细胞内的受损、变性、衰老的蛋白质或细胞器运输到溶酶体进行降解,以实现自身的代谢需要及细胞器更新的生物学过程。在动脉粥样硬化过程中,自噬参与了细胞存活和死亡的调控。病变早期,通过自噬可抑制血管内皮细胞(vascular endothelial cell,VEC)的凋亡,延缓粥样斑块的发展;而在动脉粥样硬化后期,由于自噬的过度激活导致血管细胞自噬性死亡,胶原蛋白合成减少,纤维帽薄弱而引发斑块破裂。该文综述了自噬对动脉粥样硬化影响的最新研究成果,以期为深入了解动脉粥样硬化的机制提供参考。     

动脉粥样硬化易损斑块形成和破裂的研究进展

动脉粥样硬化能导致斑块形成。随着疾病的进展,斑块发展和破裂会引起致死性冠状动脉血栓形成,表现为急性冠脉综合征。斑块破裂后,斑块内具有高度成血栓性的物质暴露在血液中,导致血栓形成。斑块破裂主要发生于薄帽纤维斑块。此外,未破裂的斑块也可以形成血栓。然而,斑块破裂的机制仍不太清楚。本文将讨论动脉粥样硬化斑块发生和发展机制、斑块是如何参与危及生命的血栓形成等问题。     

核因子кB与动脉粥样硬化新进展

动脉粥样硬化(atherosclerosis,As)是一种炎症性病变,它以血管壁上巨噬细胞源性的泡沫细胞和大量趋化因子、细胞因子和生长因子堆积为主要特征.这些因手调节着固有细胞的迁移、分化和转归,最终影响动脉粥样硬化斑块形成,其中一个关键的调节因子就是转隶因子核因子-кB(NF-кB).过去它都被一直认为是一个促进动脉粥样硬化的因子,主要是由于它调节许多与动脉粥样硬化有关促炎基因的表达.最近有文献报道说NF-кB有可能在促炎、抗炎、细胞的生存和增值方面巧妙地监护着动脉粥样硬化过程的平衡.因此,本文就NF-кB与动脉粥样硬化病变有关的启动、泡沫细胞的形成、炎症、免疫、平滑肌细胞增值、纤维帽形成、细胞凋亡关系的新进展作一综述.     

吸烟与血管钙化

吸烟是动脉粥样硬化的主要危险因素之一,然而吸烟与血管钙化(vascular calcification)之间的相关性尚未完全明确。越来越多证据表明吸烟可能是血管钙化的一个独立危险因素,其中尼古丁在血管钙化发生发展过程中的作用应得到重视和阐明。本文就吸烟与血管钙化的相关性及其机制研究进展简要作一综述,以期通过戒烟宣传防治血管钙化相关心血管疾病。     

动脉粥样硬化易损斑块的核医学和磁共振分子影像学研究进展

动脉粥样硬化分子影像学通过使用具有敏感性和特异性影像对比的分子探针针对动脉粥样硬化斑块相关的特定分子进行分子成像.该方法会极大地提高对动脉粥样硬化病变特性的检测水平和增强对该病变特征,尤其对斑块的组成成份的识别能力.斑块的组成成份和斑块的破裂、斑块的易损性以及斑块破裂后导致的结果密切相关.因此了解斑块组成成份的在体无创性检测将对动脉粥样硬化病人的治疗和判断预后产生非常重要的临床应用价值.     

维持性血液透析患者血清sTWEAK水平与冠状动脉钙化的相关性研究

目的:探讨维持性血液透析患者血清可溶性肿瘤坏死因子样凋亡微弱诱导剂(s TWEAK)水平与冠状动脉钙化的关系。方法:选择维持性血液透析患者60例和健康对照组30例,采用双抗体夹心酶联免疫吸附技术测定其血清s TWEAK水平,采用多层螺旋CT(MSCT)测定其冠状动脉钙化积分(CACs),比较两组的血清s TWEAK水平、CACs,并分析二者的相关性及血液透析患者冠状动脉钙化的危险因素。结果:血液透析患者血清s TWEAK水平显著低于正常对照组,分别为186.23(148.35,220.74)pg/m L和265.13(210.91,298.22)pg/m L,差异有统计学意义(P<0.01)。CACs>400的血液透析患者血清s TWEAK水平显著高于CACs≤400者,分别为220.73(189.70,251.67)pg/m L和146.07(138.43,180.11)pg/m L,差异有统计学意义(P<0.01)。Spearman等级相关分析显示血液透析患者的血清s TWEAK水平与患者的CACs呈明显正相关(r=0.482,P<0.01)。多因素逐步回归分析显示影响血液透析患者CACs严重程度的因素有血清s TWEAK水平、年龄、透析龄、糖尿病(P<0.05)。结论:维持性血液透析患者血清s TWEAK水平较正常人降低,但在血液透析患者s TWEAK范围内,高水平的血清s TWEAK水平与重度冠状动脉钙化相关;血清s TWEAK可能参与了血液透析患者冠状动脉钙化的发生、发展。     

大鼠动脉钙化诱导过程中炎症小体复合物分子的变化

目的:以SD大鼠动脉钙化为模型,研究钙化发生过程中炎症小体复合物分子的变化。方法:大鼠皮下注射维生素D3诱导动脉钙化,并用HE染色检测动脉钙化的发生,用半定量PCR测定钙化发展过程中细胞内NALP3炎症小体复合物核心蛋白NALP3、ASC和Caspase-1的mRNA水平变化。结果:随着动脉钙化的发展,细胞内NALP3、ASC和Caspase-1的mRNA表达水平逐步增加。结论:构建了大鼠动脉钙化模型,并且发现NALP3炎症小体复合物在动物钙化诱导过程中表达增加,为进一步研究动脉钙化的机制及筛选抗动脉硬化药物打下基础。     

Intracellular precipitation of hydroxyapatite mineral and implications for pathologic calcification

In contrast to physiologic biomineralization occurring in bones, teeth and otoconia in vertebrates, calcification of soft tissues occurs in many pathologic conditions. Although similarities have been noted between the two processes, and despite the important clinical consequences of ectopic calcification, the molecular mechanisms regulating ectopic calcification are poorly understood. Although calcification is mainly extracellular, intracellular calcification has been reported and might indeed contribute to pathologic calcification of soft tissues. To better understand the process of intracellular calcification as a potential origin for pathologic calcification, and to examine the role of proteoglycans in this process, we investigated a pattern of intracellular nucleation and growth of hydroxyapatite in Madin–Darby Canine Kidney (MDCK) epithelial cells using electron microscopy, secondary ion mass spectroscopy (NanoSIMS), cytochemical staining, immunolabeling and biochemical analysis. We report here that under mineralizing cell culture conditions where β-glycerophosphate (βGP) was added as an exogenous organic source of phosphate, βGP-cleaving alkaline phosphatase activity increased and hydroxyapatite crystals subsequently nucleated within intracellular, membrane-bounded compartments. The small, leucine-rich proteoglycan decorin was also upregulated and associated with mineral in these cultures. Such information provides insight into the mechanisms leading to pathologic calcification and describes a process whereby hydroxyapatite deposition in cells might lead to ectopic calcification.     

INCOMPLETENESS OF THE COCCOSPHERE AS A POSSIBLE STIMULUS FOR COCCOLITH FORMATION IN PLEUROCHRYSIS CARTERAE(PRYMNESIOPHYCEAE)1

Pleurochrysis carterae is a marine biflagellate that produces calcified structures called coccoliths. The coccoliths are formed inside the cells and released from the latter after formation. The light dependence of calcium incorporation in this species was studied using⁴⁵Ca as a tracer. Cells exposed to a repeating cycle of 16 h of light and 8 h of darkness incorporated calcium in extracellular coccoliths at a more or less constant rate throughout a cycle. The cells divided during the dark periods with a concomitant decrease in size. Their size increased during the light periods Coccolith formation in cells incubated in continuous darkness was greatly reduced and finally ceased. These cells did not divide and did not increase in size. Removal of extracellular coccoliths prior to the calcium incorporation experiments stimulated coccolith formation both in dark-incubated cells and in cells exposed to a repeating light-dark cycle. Cells in the stationary phase of growth ceased producing coccoliths. Calcification could be induced in these cells by removal of the extracellular coccoliths. Based on these findings we suggest that cells of Pleurochrysis carterae tend to produce a complete cover of coccoliths and that the available cell surface is a factor controlling coccolith formation.     

INCOMPLETENESS OF THE COCCOSPHERE AS A POSSIBLE STIMULUS FOR COCCOLITH FORMATION IN PLEUROCHRYSIS CARTERAE (PRYMNESIOPHYCEAE)1

Pleurochrysis carterae is a marine biflagellate that produces calcified structures called coccoliths. The coccoliths are formed inside the cells and released from the latter after formation. The light dependence of calcium incorporation in this species was studied using ⁴⁵Ca as a tracer. Cells exposed to a repeating cycle of 16 h of light and 8 h of darkness incorporated calcium in extracellular coccoliths at a more or less constant rate throughout a cycle. The cells divided during the dark periods with a concomitant decrease in size. Their size increased during the light periods. Coccolith formation in cells incubated in continuous darkness was greatly reduced and finally ceased. These cells did not divide and did not increase in size. Removal of extracellular coccoliths prior to the calcium incorporation experiments stimulated coccolith formation both in dark-incubated cells and in cells exposed to a repeating light-dark cycle. Cells in the stationary phase of growth ceased producing coccoliths. Calcification could be induced in these cells by removal of the extracellular coccoliths. Based on these findings we suggest that cells of Pleurochrysis carterae tend to produce a complete cover of coccoliths and that the available cell surface is a factor controlling coccolith formation.     

A Suggestion fob Prevention of Loose Sections in the Bodian Peotargol Method

Prolonged immersion in an aqueous medium such as the protargol bath in the original Bodian method for paraffin sections may increase any tendency for sections to separate from the slide during their subsequent reduction.     

Morphological and chemical characterization of mineral concretions in the freshwater bivalve Anodonta cygnea (Unionidae)

The freshwater mussel Anodonta cygnea is commonly used as a model organism for biomineralization studies, its peculiar morphofunctional properties also make it an excellent environmental biomonitor. The first detailed on the calcareous concretions from gill and mantle tissue, as well as fluids of the freshwater bivalve A. cygnea, supported by histological, scanning, spectrometry, and spectroscopy analyses. Through these analyses, the morphology, structure, and chemical characterization of these biomineral concretions were accomplished. The concretions represent a high percentage of the dry weight of these organisms. In gill tissue, it can reach up to 50% of dry weight prior to reproductive maturity. Analysis of elemental composition of the tissue concretions showed the presence of calcium and phosphate, as main components, associated with other residual elements like iron, manganese, magnesium, and zinc. Concretions are arranged in concentric alternated layers of organic and inorganic matrix. The shape and size of the concretions vary substantially, from very small, less than 1 μm diameter with very regular round structure, found mainly in the mantle tissue, to more than 50 μm length with irregular globular clusters, found predominantly in the gills. The microstructural organization is of a hydroxyapatite polymorphism in the mantle, in contrast to the gills, which exhibit irregular structure and carbonated hydroxyapatite polymorphism. These differences are supported by higher contents of dinitrogen pentoxide, magnesium, and iron in the mantle concretions, but higher contents of manganese and zinc in the gills. Furthermore, the results indicate that the mineral concretion formation in A. cygnea is a hemocytes reaction to particle or toxic invasions. A second relevant role, concerns the close involvement of these microspherules on the adult and larval shell calcification. J. Morphol. 276:65–76, 2015. © 2014 Wiley Periodicals, Inc.