血管内皮细胞衰老与血管疾病

细胞衰老是指细胞在各种应激条件下出现周期阻滞,不可逆地丧失增殖能力,其形态、基因表达和功能都发生特定变化的过程。研究表明,血管内皮细胞衰老可以通过削弱血管功能,促进衰老相关血管疾病的发生发展。然而,有关内皮细胞衰老的发生机制以及内皮细胞衰老影响血管功能及衰老相关血管疾病的潜在机制尚待挖掘。本文从血管内皮细胞衰老相关的信号通路,以及血管内皮细胞衰老与血管功能和血管相关疾病（动脉粥样硬化、高血压和糖尿病血管并发症）的最新研究进展进行综述,为进一步认识血管疾病的发病机制,延缓血管衰老提供新的思路。     

血管内皮生长因子与血管生成

本综述了血管内皮生长因子结构特点、体内分布,正常及病理条件下的表达水平变化及其生物学功能,并对血管通透性与血管生成之间的关系进行了评述。     

血管形成

发现 杜塞尔多夫大学的Ecki Lammert和同事们想要终结一个争论：内胚层细胞是通过空泡的扩张形成来形成血管,还是先扁平生长,而后卷曲形成一个空心圆柱？用功能强大的显微技术,Strilic发现两排细胞先是并列生长,而后在细胞骨架的收缩下分开,形成空心圆柱。     

血管外周脂肪与血管稳态失衡

血管外周脂肪(perivascular adipose tissue, PVAT)是贴近血管外膜的脂肪组织,是活跃的旁自分泌器官,能够分泌多种活性物质,由外而内地影响着血管的稳态。PVAT是一种起源于独特前体细胞的脂肪组织,它兼具白色和棕色脂肪组织样特征。生理状态下,PVAT具有产热能力,并发挥机械保护和血管扩张的作用。病理状态下,比如肥胖、糖尿病、高脂血症、高血压和衰老等,PVAT表型改变和功能失调,表现为脂肪组织扩张、棕色脂肪“白色化”、脂肪细胞中脂质的异常积累和脂肪因子的异常分泌等。近年研究显示,PVAT表型的改变参与了血管重塑、动脉粥样硬化、腹主动脉瘤和高血压等多种病理过程或疾病的发生发展。     

人造血管

美国生物工程技术人员培植出一种人造血管 ,其比真正的血管坚韧 2 0倍 ,而且完全由人体细胞长成 ,表现出真正的人体组织的外观、功能和感觉 ,适用于那些需要做冠状动脉搭桥手术的病人。用来制造人造血管的细胞是从病人腿部的血管中提取的 ,然后细胞被放进模拟人体环境的生物反应器中生长 ,这样 ,皮肤细胞被改造成血管细胞。由病人自身细胞长成的血管有很多优点 :它不可能出现排异反应 ,血管周围也不会形成疤痕。因此 ,医生可以培植出更细小更精确的血管 ,和真正的血管相吻合 ,并且能改善血液的流动方式。人造血管…     

微重力对血管及血管内皮细胞的影响

血管系统功能紊乱是微重力诱导立位耐力不良发生的重要因素之一。血管内皮细胞是覆盖在血管内壁上组成血管管腔面的一层单层细胞,是血管壁的重要组成部分,并且在血管功能调控中起到渗透屏障、调节舒缩等重要作用。近年研究发现,微重力可对不同部位的血管系统和血管内皮细胞产生不同的影响,比如可使脑动脉缩血管反应性增加、舒血管反应性下降,颈动脉和腹主动脉缩血管和舒血管反应性下降,肺动脉缩血管反应性下降、舒血管反应性增加,肠系膜动静脉和下肢动脉缩血管反应性下降。另外,微重力可促进大血管来源的内皮细胞生长,但抑制微血管来源的内皮细胞的生长。本文就微重力对血管及血管内皮细胞影响的研究进展作一概述。     

血管内皮细胞舒、缩血管物质与心血管疾病

血管内皮细胞的多面性功能已日益为人们所认识。它不仅是血液和血管平滑肌间的生理性屏障,而且是高度活跃的代谢库如内皮细胞使缓激肽失活,花生四烯酸代谢产生前列环素(PGI_2)。除扩血管剂PGI_2外,已发现有内皮细胞舒张因子(EDRF或NO)和内皮细胞高极化因子(EDHF)。PGI_2和EDRF已列入为调节正常血液循环和维持机体内环境稳定的重要内源性物质。近年来,又发现内皮细胞还存在缩血管物质,如血管紧张素Ⅱ,内皮细胞收缩因子(EDCF)和内皮素(Endothelin)等。它们与心血管疾病的发生和发展有着密切关系。     

血管生长素与治疗性血管生成的研究进展

血管生长素(angiogenin,ANG) 是一种分泌性的单链碱性蛋白质,由123个氨基酸组成,分子量为14.4kD,广泛分布在人体中.ANG属于核糖核酸酶超家族中的一员,具有低核糖核酸酶活性.研究证实,ANG是一种有效的促血管生成因子,参与血管生成的各个阶段,是其它血管生成因子诱导新血管生成的枢纽,在缺血性疾病的治疗方面显示出巨大的潜能.本文对ANG在治疗性血管生成方面的研究进展作一综述.     

凝血因子重塑血管

血管的完整性对机体的血液运输至关重要。当血管受损时 ,纤维蛋白在伤口处聚集血小板形成血凝块而止血。通常认为 ,凝血酶对血小板的激活是通过与其表面表达的蛋白酶激活的Ｇ蛋白偶联受体 (ｐｒｏｔｅａｓｅ ａｃｔｉｖａｔｅｄＧｐｒｏｔｅｉｎ -ｃｏｕｐｌｅｄｒｅｃｅｐｔｏｒｓ ,ＰＡＲｓ)而实现的。圣佛朗西科加利福尼亚大学心血管研究中心的ＣｏｕｒｔｎｅｙＴ .Ｇｒｉｆｆｉｎ等报道 ,在胚胎发育中ＰＡＲ1在血管内皮细胞中表达 ,ＰＡＲ1缺陷的胚鼠有近半数在妊娠中期因出血不止而死 ;若用内皮细胞特异的启动子使ＰＡＲ1表达 ,则会减…     

选择性制造血管

当组织需要氧气和养料时 ,它们释放能促进血管生长的分子。无组织特异性的血管内皮生长因子 (ｖａｓ ｃｕｌａｒｅｎｄｏｔｈｅｌｉａｌｇｒｏｗｔｈｆａｃｔｏｒ ,ＶＥＧＦ)即是其中一种。但由于不同组织对血管需求不同 ,还应存在组织特异性的血管生长因子。加利福尼亚大学的Ｌｅｌｏｕｔｅｒ及其同事首次发现此类分子内分泌腺衍生的血管内皮生长因子 (ｅｎｄｏｃｒｉｎｅ ｇｌａｎｄ ｄｅｒｉｖｅｄｖａｓｃｕｌａｒｅｎｄｏｔｈｅｌｉａｌｇｒｏｗｔｈｆａｃｔｏｒ ,ＥＧ ＶＥＧＦ)。它能特异性诱导内分泌腺毛细血管内皮细胞的增殖和迁移…     

ANG II potentiates mitogenic effect of norepinephrine in vascular muscle cells: role of FGF-2

We examined the possible cooperation between norepinephrine (NE) and ANG II on proliferation of cultured vascular smooth muscle cells (VSMCs) and the involved cellular mechanisms. Nanomolar NE concentrations stimulated VSMC proliferation through a prazosin-sensitive effect. The pretreatment of cells with 100 nM ANG II for 24 h significantly potentiated the NE-induced VSMC proliferation; this potentiating effect of ANG II was blocked by losartan but was unaffected by the AT(2) receptor antagonist PD-123177. ANG II pretreatment also potentiated the increase in inositol phosphate turnover and upregulated the cell expression of fibroblast growth factor (FGF-2) induced by NE. Anti-FGF-2 neutralizing antibodies prevented the potentiating effect of ANG II on NE-induced cell growth. Both ANG II and NE stimulated extracellular signal-related kinase (ERK1) activation, but an ANG II potentiation of the effect of NE on ERK1 activity was not detectable. Moreover, ANG II significantly increased protein synthesis but did not potentiate the hypertrophic effect of NE. These findings demonstrate that ANG II and NE cooperate in promoting VSMC growth and that FGF-2 upregulation is involved in this effect.     

氯化钠对培养的大鼠主动脉平滑肌细胞的心房钠尿肽受体的调节

培养的卒中型自发性高血压大鼠(SHR_(sp))及其对照 WKY 大鼠主动脉平滑肌细胞(VSMC)上存在心房钠尿肽(ANP)的特异性受体,它们与~(125)I-ANP 的最大结合量(B_(max))是:SHR_(sp)3.65±0.13和 WKY 1.89±0.09 pmol/mg pr(P<0.01);解离平衡常数(Kd)值分别是72.6±10.2和42.0±4.8×10~(-12)mol/L(P<0.01)。 两种细胞内介导舒血管作用的第二信使、环磷酸乌苷(cGMP)的基础浓度无显著差异,对相同剂量 ANP 刺激引起 cGMP 分别增加139(SHRsp)和271(WKY)倍。可见 SHRsp 的 VSMC ANP 受体数量虽比 WKY大鼠增多,但对相同剂量 ANP 引起的 cGMP 增加反应及 ANP 受体的亲和力均显著降低。高盐培养液孵育24h 后,细胞表面 ANP 受体的亲和力改变不明显,但受体数量下调,SHRsp 和 WKY 大鼠分别降至对照的34.8±8.2%和38.6±9.4%,细胞对 ANP 引起的 cGMP增加反应明显降低,且均以 SHR_(sp)较显著。提示后两种变化可能在高盐促进血压升高的机制中起作用。     

The GTPase ARF6 Controls ROS Production to Mediate Angiotensin II-Induced Vascular Smooth Muscle Cell Proliferation

High reactive oxygen species (ROS) levels and enhanced vascular smooth muscle cells (VSMC) proliferation are observed in numerous cardiovascular diseases. The mechanisms by which hormones such as angiotensin II (Ang II) acts to promote these cellular responses remain poorly understood. We have previously shown that the ADP-ribosylation factor 6 (ARF6), a molecular switch that coordinates intracellular signaling events can be activated by the Ang II receptor (AT₁R). Whether this small GTP-binding protein controls the signaling events leading to ROS production and therefore Ang II-dependent VSMC proliferation, remains however unknown. Here, we demonstrate that in rat aortic VSMC, Ang II stimulation led to the subsequent activation of ARF6 and Rac1, a key regulator of NADPH oxidase activity. Using RNA interference, we showed that ARF6 is essential for ROS generation since in conditions where this GTPase was knocked down, Ang II could no longer promote superoxide anion production. In addition to regulating Rac1 activity, ARF6 also controlled expression of the NADPH oxidase 1 (Nox 1) as well as the ability of the EGFR to become transactivated. Finally, ARF6 also controlled MAPK (Erk1/2, p38 and Jnk) activation, a key pathway of VSMC proliferation. Altogether, our findings demonstrate that Ang II promotes activation of ARF6 to controls ROS production by regulating Rac1 activation and Nox1 expression. In turn, increased ROS acts to activate the MAPK pathway. These signaling events represent a new molecular mechanism by which Ang II can promote proliferation of VSMC.     

Involvement of mitochondrial fission in calcium sensing receptor-mediated vascular smooth muscle cells proliferation during hypertension

Hyperproliferation of vascular smooth muscle cells (VSMC) is a major risk factor for cardiovascular diseases. Proper mitochondrial fission and fusion is involved with VSMC function. However, the role and mechanism of mitochondrial morphological changes in VSMC proliferation are not well understood. Here, we found that calcium sensing receptor (CaSR) was increased in the aortas from spontaneous hypertensive rats (SHRs) compared with age-matched Wistar Kyoto (WKY) rats. There was also an increase in mitochondrial fission and VSMC proliferation, which was attenuated by Calhex231. In primary rat VMSC, angiotensin II (Ang II) stimulation induced cytosolic [Ca²⁺]_i increase, mitochondrial shortening and proliferation, all of which could be attenuated by pretreatment with mitochondrial division inhibitor-1 (Mdivi-1) and Calhex231. Our data indicate that CaSR-mediated mitochondrial fission could be a therapeutic target for hyperproliferative disorders.     

Role of integrin-linked kinase in vascular smooth muscle cells: regulation by statins and angiotensin II

Our goal was to characterize the role of integrin-linked kinase (ILK) in vascular smooth muscle cells (VSMC), which play a crucial role in atherogenesis. Transfection of VSMC with wild-type and dominant-negative ILK cDNA constructs revealed that ILK mediates migration and proliferation of VSMC but has no effect on VSMC survival. The pro-atherogenic mediator angiotensin II increases ILK protein expression and kinase activity while statin treatment down-regulates ILK in VSMC. Functionally, ILK is necessary for angiotensin II-mediated VSMC migration and proliferation. In VSMC transduced with dominant-negative ILK, statins mediate an additive inhibition of VSMC migration and proliferation, while transfection with wild-type ILK is sufficient to overcome the inhibitory effects of statin treatment on VSMC migration and proliferation. In vivo, ILK is expressed in VSMC of aortic sections from wild-type mice where it is down-regulated following statin treatment and up-regulated following induction of atherosclerosis in apoE-/- mice. These data identify ILK as a novel target in VSMC for anti-atherosclerotic therapy.     

Modulation of ANP-C receptor signaling by arginine-vasopressin in A-10 vascular smooth muscle cells: role of protein kinase C

We have previously shown that pretreatment of A-10 vascular smooth muscle cells (VSMC) with angiotensin II (Ang II) attenuated atrial natriuretic peptide receptor-C (ANP-C)-mediated inhibition of adenylyl cyclase without altering [125I]ANP binding. In the present studies, we have investigated the modulation of ANP-C receptor signaling by arginine-vasopressin (AVP). Pretreatment of A-10 VSMC with AVP for 24h resulted in a reduction in ANP receptor binding activity by about 50% (B(max); control cells, 22.9+/-2.5 fmol/mg protein, AVP-treated cells, 11.4+/-1.2 fmol/mg protein). In addition, the expression of ANP-C receptor as determined by immunoblotting was also decreased by about 50% by AVP treatment, which was prevented by GF109203X, an inhibitor of protein kinase C (PKC). The decreased expression of ANP-C receptor was reflected in an attenuation of ANP-C receptor-mediated inhibition of adenylyl cyclase. C-ANP(4-23) [des(Gln(18),Ser(19),Gln(20),Leu(21),Gly(22))ANP(4-23)-NH(2)], a ring deleted peptide of ANP that interacts specifically with ANP-C receptor, inhibited adenylyl cyclase activity by about 30% in control cells, which was completely attenuated in AVP-treated cells. This attenuated inhibition was significantly restored by GF 109203X. In addition, AVP treatment augmented the levels of Gialpha-2 and Gialpha-3 proteins; however, the Gi functions were completely attenuated. The increased expression of Gialpha proteins induced by AVP was inhibited by GF109203X as well as by actinomycin D treatments. In addition, AVP treatment also enhanced the expression of Gsalpha protein and Gsalpha-mediated stimulation of adenylyl cyclase by GTPgammaS, N-ethylcarboxamide adenosine (NECA), and forskolin (FSK), whereas the levels of Gbeta were not altered by AVP treatment. These results indicate that AVP-induced PKC signaling may be responsible for the down-regulation of ANP-C receptor that results in the attenuation of C-ANP(4-23)-mediated inhibition of adenylyl cyclase activity, and suggest a cross-talk between vasopressin V(1) and ANP-C receptor-mediated signaling pathways.     

Anti-proliferative effect of rosiglitazone on angiotensin II-induced vascular smooth muscle cell proliferation is mediated by the mTOR pathway

VSMC (vascular smooth muscle cell) proliferation contributes significantly to intimal thickening in atherosclerosis, restenosis and venous bypass graft diseases. Ang II (angiotensin II) has been implicated in VSMC proliferation though the activation of multiple growth-promoting signals. Although TZDs (thiazolidinediones) can inhibit VSMC proliferation and reduce Ang II-induced fibrosis, the mechanism underlying the inhibition of VSMC proliferation and fibrosis needs elucidation. We have used primary cultured rat aortic VSMCs and specific antibodies to investigate the inhibitory mechanism of rosiglitazone on Ang II-induced VSMC proliferation. Rosiglitazone treatment significantly inhibited Ang II-induced rat aortic VSMC proliferation in a dose-dependent manner. Western blot analysis showed that rosiglitazone significantly lowered phosphorylated ERK1/2 (extracellular-signal-regulated kinase 1/2), Akt (also known as protein kinase B), mTOR (mammalian target of rapamycin), p70S6K (70 kDa S6 kinase) and 4EBP1 (eukaryotic initiation factor 4E-binding protein) levels in Ang II-treated VSMCs. In addition, PPAR-γ (peroxisome-proliferator-activated receptor γ) mRNA increased significantly and CTGF (connective tissue growth factor), Fn (fibronectin) and Col III (collagen III) levels decreased significantly. The results demonstrate that the rosiglitazone directly inhibits the pro-atherosclerotic effect of Ang II on rat aortic VSMCs. It also attenuates Ang II-induced ECM (extracellular matrix) molecules and CTGF production in rat aortic VSMCs, reducing fibrosis. Importantly, PPAR-γ activation mediates these effects, in part, through the mTOR-p70S6K and -4EBP1 system.     

Role of integrins in angiotensin II-induced proliferation of vascular smooth muscle cells

Angiotensin II (AII) binds to G protein-coupled receptor AT(1) and stimulates extracellular signal-regulated kinase (ERK), leading to vascular smooth muscle cells (VSMC) proliferation. Proliferation of mammalian cells is tightly regulated by adhesion to the extracellular matrix, which occurs via integrins. To study cross-talk between G protein-coupled receptor- and integrin-induced signaling, we hypothesized that integrins are involved in AII-induced proliferation of VSMC. Using Oligo GEArray and quantitative RT-PCR, we established that messages for α(1)-, α(5)-, α(V)-, and β(1)-integrins are predominant in VSMC. VSMC were cultured on plastic dishes or on plates coated with either extracellular matrix or poly-d-lysine (which promotes electrostatic cell attachment independent of integrins). AII significantly induced proliferation in VSMC grown on collagen I or fibronectin, and this effect was blocked by the ERK inhibitor PD-98059, suggesting that AII-induced proliferation requires ERK activity. VSMC grown on collagen I or on fibronectin demonstrated approximately three- and approximately sixfold increases in ERK phosphorylation after stimulation with 100 nM AII, respectively, whereas VSMC grown on poly-d-lysine demonstrated no significant ERK activation, supporting the importance of integrin-mediated adhesion. AII-induced ERK activation was reduced by >65% by synthetic peptides containing an RGD (arginine-glycine-aspartic acid) sequence that inhibit α(5)β(1)-integrin, and by ～60% by the KTS (lysine-threonine-serine)-containing peptides specific for integrin-α(1)β(1). Furthermore, neutralizing antibody against β(1)-integrin and silencing of α(1), α(5), and β(1) expression by transfecting VSMC with short interfering RNAs resulted in decreased AII-induced ERK activation. This work demonstrates roles for specific integrins (most likely α(5)β(1) and α(1)β(1)) in AII-induced proliferation of VSMC.     

Human-derived vascular smooth muscle cells produce angiotensin II by changing to the synthetic phenotype

We investigated whether vascular smooth muscle cells (VSMC)-derived from human produce angiotensin (Ang) II upon change from the contractile phenotype to the synthetic phenotype by incubation with fibronectin (FN). Expression of alpha-smooth muscle (SM) actin, apparent in the contractile phenotype, was decreased by FN. Expressions of matrix Gla and osteopontin, apparent in the synthetic phenotype, were increased by FN. Ang II measured by radioimmunoassay (RIA) was significantly increased in human VSMC by FN. Expression of mRNAs for Ang II-generating proteases cathepsin D, cathepsin G, ACE, and chymase was increased by FN. Expressions of cathepsin D and cathepsin G proteins were also increased by FN. Ang I-generating activity, which was inhibited by an aspartyl protease inhibitor pepstatin A, was readily detected in the conditioned medium from human VSMC. Antisense oligodeoxynucleotides (ODNs) that hybridize with cathepsin D and cathepsin G significantly inhibited FN-increased Ang II in conditioned medium and cell extracts. In VSMC conditioned medium, FN-induced elevation of Ang II was significantly inhibited by temocapril but not by chymostatin. Ang II type 1 receptor antagonist CV11974 completely, and antisense cathepsin D and cathepsin G ODNs partially inhibited the FN-stimulated growth of human VSMC. These results indicate that the change of homogeneous cultures of human VSMC from the contractile to the synthetic phenotype sequentially increases expression of proteases cathepsin D, cathepsin G, and ACE, production of Ang II and productions of growth factors, culminating in VSMC proliferation. These findings implicate a new mechanism for the pathogenesis of human vascular proliferative diseases.