Circulating smooth muscle progenitor cells in arterial remodeling

The proliferation and migration of vascular smooth muscle cells (SMCs) from the media toward the intimal layer are key components in vascular proliferative diseases. In addition, the differentiation of circulating bone marrow-derived mononuclear cells (BMMCs) into SMCs has been described to contribute to lesion progression in experimental models of atherosclerosis, transplant arteriosclerosis, and neointima formation. In vitro, CD14⁺ BMMCs from peripheral blood acquire a spindle-shaped phenotype and express specific SMC markers in response to platelet-derived growth factor-BB. However, the ‘trans-differentiation’ capacity of BMMCs into definitive SMCs in vivo remains a highly controversial issue. Whereas SMCs within atherosclerotic plaques have been demonstrated to be exclusively of local origin, more severe injury models have shown a wide diversity of SMCs or smooth muscle-like cells derived from BMMCs. In hindsight, these discrepancies may be attributed to methodological differences, e.g., the use of high-resolution microscopy or the specificity of the SMC marker proteins. In fact, the analysis of mouse strains that express marker genes under the control of a highly specific smooth muscle-myosin heavy chain (SM-MHC) promoter and a time-course analysis on the dynamic process of neointima formation have recently shown that BMMCs temporarily express α-smooth muscle actin, not SM-MHC. Additionally, BM-derived cells disappear from the neointimal lesion after the inflammatory response to the injury has subsided. Although CD14⁺/CD68⁺ have important paracrine effects on arterial lesion progression, BMMCs account for more of the ‘SMC-like macrophages’ than the highly ‘trans-differentiated’ and definitive SMCs in vivo. This article is part of a special issue entitled, "Cardiovascular Stem Cells Revisited".     

辛伐他汀对大鼠平滑肌祖细胞和内皮祖细胞分化的不同影响

目的：观察辛伐他汀对平滑肌祖细胞（SPC）和内皮祖细胞（EPC）分化的影响。方法：采用密度梯度离心法获取大鼠骨髓单个核细胞,将其接种在纤维连接素包被培养板,加入不同浓度辛伐他汀（0．01～10μmol／L）培养8d。采用平滑肌肌动蛋白免疫荧光染色鉴定骨髓源性SPC,激光共聚焦显微镜鉴定FITC—UEA—I和Di I-acLDL双染阳性细胞为正在分化的EPC,并在倒置荧光显微镜下计数。结果：辛伐他汀显著抑制骨髓单个核细胞分化为SPC。0．01μmol／L辛伐他汀组与对照组SPC数量分别为79±5对85±4（P〈0．05）。辛伐他汀显著促进骨髓单个核细胞向EPC分化,其促进作用随辛伐他汀浓度升高而增加,在1．0μmol／L达最大效应。1μmol／L辛伐他汀组与对照组EPC数量分别为87±5对39±4（P〈0．01）。结论：辛伐他汀选择性抑制骨髓单个核细胞向SPC分化,促进其向EPC分化,局部应用有促进损伤血管再内皮化和抑制新生内膜过度增生的可能。     

The origin and differentiation potential of smooth muscle cells in coronary atherosclerosis

OBJECTIVES: To determine the phenotypical state of smooth muscle cells during the pathogenesis of an atherosclerotic lesion, and to determine the morphological state of the endothelium and the origin of foam cells. METHODS: Twenty-one samples of atherosclerotically changed right coronary arteries, which were divided into six subgroups based on the stage of atherosclerosis, were analyzed. The tissues were fixed in formalin and embedded in paraffin. Sections of 5 mum thickness were stained immunocytochemically using a labelled streptavidin-biotin/horse radish peroxidase kit (Dako, Denmark) for the identification of vimentin, alpha-smooth muscle actin, myosin heavy chains, desmin, S-100 protein, CD3, CD31, CD34, CD45, CD68 and proliferating cell nuclear antigen protein. RESULTS: The present study showed that there is first functional and then morphological damage of the endothelium in the late stages of atherosclerosis. The preatheroma stage revealed the presence of intimal changes of smooth muscle cells, with expression of vimentin and alpha-smooth muscle actin and a lack of expression of desmin, which led to a switch to a synthetic phenotype. The described changes progressed into the later stages of atherosclerosis. Along with these changes, a large number of foam cells of variant origin were observed; some of the foam cells developed from monocyte-macrophage lineage (CD68-immunoreactive) and others originated from smooth muscle cells (vimentin- and S-100-immunoreactive). The late stages of atherosclerosis development, such as the atheroma stage, include intimal changes with the formation of a lipid core (S-100-immunoreactive cells and cell necrosis), while fibrosis in the lipid core and the accumulation of collagen fibres with extreme hypocellularity are characteristics of the fibroatheroma stage.     

Human embryonic stem cell-derived vascular smooth muscle cells in therapeutic neovascularisation

Ischemic diseases remain one of the major causes of morbidity and mortality throughout the world. In recent clinical trials on cell-based therapies, the use of adult stem and progenitor cells only elicited marginal benefits. Therapeutic neovascularisation is the Holy Grail for ischemic tissue recovery. There is compelling evidence from animal transplantation studies that the inclusion of mural cells in addition to endothelial cells (ECs) can enhance the formation of functional blood vessels. Vascular smooth muscle cells (SMCs) and pericytes are essential for the stabilisation of nascent immature endothelial tubes. Despite the intense interest in the utility of human embryonic stem cells (ESCs) for vascular regenerative medicine, ESC-derived vascular SMCs have received much less attention than ECs. This review begins with developmental insights into a range of smooth muscle progenitors from studies on embryos and ESC differentiation systems. We then summarise the methods of derivation of smooth muscle progenitors and cells from human ESCs. The primary emphasis is on the inherent heterogeneity of smooth muscle progenitors and cells and the limitations of current in vitro characterisation. Essential transplantation issues such as the type and source of therapeutic cells, mode of cell delivery, measures to enhance cell viability, putative mechanisms of benefit and long-term tracking of cell fate are also discussed. Finally, we highlight the challenges of clinical compatibility and scaling up for medical use in order to eventually realise the goal of human ESC-based vascular regenerative medicine.     

血管内膜平滑肌细胞增殖状态下的凋亡细胞标记

目的探讨动脉损伤后内膜平滑肌细胞增殖状态下的凋亡细胞的水平及其出现的时间的部位,深入地研究血管成形术后再狭窄的形成机制,为抑制再狭窄的形成提供可能的干预措施。方法和结果应用球囊导管损伤小型猪髂动脉制备成内膜增殖所致的血管狭窄模型,采用计算机彩色图像分析系统动态观察损伤后１天、３天、６天、１２天和３０天的内膜平滑肌细胞增殖状况,并用末端转移酶介导的ｄＵＴＰ标记在ＤＮＡ３′－ＯＨ的方法（ＴＵＮＥＬ）来标记凋亡细胞。结果表明,损伤后６天以内,未出现凋亡细胞,从１２天起,仅在增殖的内膜中出现了较低水平的凋亡,即１２天（１．９４±０．４２）％和３０天（１．３６±０．３１）％,后二者差异无显著性。可以认为,较低水平的凋亡细胞可能是再狭窄形成过程中的病理学特征。结论平滑肌细胞的凋亡是血管损伤后狭窄形成过程中的一个重要的病理学特征,相比大量增殖的内膜平滑肌细胞,较低水平的凋亡可能是血管狭窄形成的机制之一,这提示,对低水平的凋亡进行适时适量的诱导,可能为抑制再狭窄提供新的选择。     

腺病毒介导的HCY2基因对血管平滑肌细胞凋亡的诱导作用

目的　观察高同型半胱氨酸诱导基因HCY2对于平滑肌细胞的作用。方法　以复制缺陷型腺病毒作为载体 ,将HCY2基因转移到平滑肌细胞中。提取平滑肌细胞的DNA ,进行凝胶电泳及ELISA ,行DNA片段化分析。用流式细胞术观察平滑肌细胞的亚二倍体。结果　转染HCY2后平滑肌细胞的DNA断裂成相差 2 0 0bp左右的片段 ,流式细胞术测定时发现 ,位于亚二倍体区的平滑肌细胞明显增多。结论　HCY2基因能引起平滑肌细胞的凋亡。     

同型半胱氨酸对平滑肌细胞增殖的影响及机制

目的 研究同型半胱氨酸(HCY)对平滑肌细胞增殖的影响及机制.方法利用~3H-TdR掺入、血小板衍化生长因子(PDGF)、血管紧张素Ⅱ(AugⅡ)生物活性检测,观察HCY对平滑肌细胞增殖、PDGF和AngⅡ的影响.结果HCY促进平滑肌细胞增殖,同时使平滑肌细胞分泌PDGF、AngⅡ增加,二者均有剂量效应关系.结论HCY促进血管平滑肌细胞增殖,可能是通过促使PDGF、AngⅡ分泌增加实现的.     

同型半胱氨酸促血管平滑肌细胞增殖的机制

目的　研究同型半胱氨酸 (HCY)对血管平滑肌细胞 (VSMC)细胞周期、细胞周期素和 P2 7蛋白表达的影响。方法　用流式细胞技术测定细胞周期、细胞周期素和 P2 7蛋白表达量。结果　 HCY促进 VSMC增殖和细胞 S期合成 ,同时使细胞周期素 D、E、A表达明显增加 ,P2 7蛋白表达下降。结论　 HCY促进 VSMC增殖和细胞 S期合成可能是通过增加细胞周期素 D、E、A的表达 ,抑制 VSMC中 P2 7蛋白的表达来实现的。     

可罗卡林对血管平滑肌细胞增殖及c-myc基因表达的影响

目的：观察对大鼠主动脉平滑肌细胞起负调节作用的可罗卡林(cromakalim对同型半胱氨酸(hcy)刺激的血管平滑肌细胞(vascular smooth muscle cells，VSMC)增殖及c—myc基因表达的影响。方法：在建立hcy诱导的平滑肌细胞增殖模型后，应用流式细胞术观察VSMC增殖周期的变化；并用免疫细胞化学方法观察可罗卡林对VSMC增殖及c—myc基因蛋白表达的影响。结果：可罗卡林使VSMC处于G0／G1期的细胞数显著增多(P＜0．01)，S期G2 M期的细胞数显著减少(P＜0．01．)，能够抑制hcy诱导的VSMC增殖和c—myc基因蛋白表达的增加。结论：可罗卡林对hcy诱导的VSMC增殖有显著的抑制作用，其作用机制与抑制c—myc基因表达有关。     

血管肽对离体大鼠血管平滑肌细胞增殖和c-myb mRNA表达的影响

目的　观察了血管肽 (angiopeptim ,AP)对血小板源性生长因子刺激下离体大鼠胸主动脉血管平滑肌细胞 (VSMC)增殖和c mybmRNA表达的影响 ,从分子生物学水平探讨其抗增殖作用机制。方法　采用细胞计数确定VSMC增殖状态。以Nothern印迹法测定c mybmRNA表达水平。结果　各组细胞计数分别为 (5 45± 0 5 7)× 10 4,对照组 ;(4 12± 0 13)× 10 4,30nmol L ;(3 13± 0 2 0 )× 10 4,6 0nmol L和 (2 0 3± 0 0 5 )× 10 4,12 0nmol L ;(q =10 5 0 ,10 32和 2 7 0 1,P <0 0 1)。抑制率分别为 2 9% ,5 2 %和 77%。其对VSMCc mybmRNA表达的抑制也具剂量依赖性。c mybmRNA GAPDH比值分别为1 12± 0 0 2 (对照组 ) ;0 6 1± 0 0 1,30nmol L ;0 34± 0 0 1,6 0nmol L和 0 16± 0 0 1,12 0nmol L ;q =39 2 3,6 0 0 0和 73 85 ,P <0 0 1)。结论　血管肽显著抑制VSMC增殖及c myb原癌基因表达 ,作用呈剂量依赖性。提示AP抗增殖作用与抑制晚期生长调节基因表达有关。     

Myeloid lineage of high proliferative potential human smooth muscle outgrowth cells circulating in blood and vasculogenic smooth muscle-like cells in vivo

Emerging experimental data supports a circulating precursor origin for some smooth muscle cells that participate in vasculogenesis but uncertainty exists on the precise phenotype and lineage of these vascular precursors. We determined the lineage of human smooth muscle outgrowth cells (SOC) derived from circulating blood mononuclear cells and smooth muscle-like cells present in regions of vasculogenesis in diseased arteries. Immunophenotypic characterization of SOC was performed using FACS and immunofluorescence (IF). An SOC hierarchy was determined based on in vitro clonogenic and proliferative potential. Lineage of smooth muscle-like cells in vasculogenic regions in vivo was also determined by dual IF for myeloid and smooth muscle specific markers combined with FISH for the X and Y chromosome in diseased vessel of human subjects who had undergone gender mismatched cardiac transplantation. We show here that primary high proliferative potential smooth muscle outgrowth cells (HPP-SOC) expanded in culture from human peripheral blood mononuclear cells (PBMC) and recipient-derived chimeric smooth muscle cells participating in vasculogenesis in vivo share a myeloid phenotype (CD68 and CD14 positivity). Moreover, HPP-SOC in vitro are distinct in being negative for several myeloid markers such as CD11b, CD13 and CD33, and CD45 surface antigens and chimeric SMC in vivo show no evidence of cell fusion propensity. This study provides evidence of a possible myeloid subpopulation origin for smooth muscle outgrowth cells in blood and vasculogenic smooth muscle-like cells in the intima and adventitial microvasculature of diseased arteries. These data have significant implications for understanding the role myeloid cells play in smooth muscle cell biology and vascular remodelling.     

血管去内皮损伤后平滑肌细胞凋亡的实验观察

目的 了解血管去内皮损伤后新内膜形成及平滑肌细胞(SMCs)凋亡的时相变化。方法用氮气干燥剥脱大鼠颈动脉内皮复制血管损伤模型,HE染色光镜形态计量内膜/中膜比(I/M),末端脱氧核苷酸转移酶(TdT)介导的荧光素d-uTP缺口末端标记(TRNEL)方法观察不同时间新内膜形成(I/M)及VSMC凋亡。结果 血管去内皮后四天,在SMCs增生形成的新内膜中有TUNEL法证实的细胞凋亡,I/M加比,凋亡指数(TUNELI)分别为0.12±0.06,2.4±1.98。在七天,内膜明显增厚(I/M为0.6±0.15,与四天比,P<0.05),TUNELI达到最大值(为9.3±3.8,与四天比,P<0.05)。到第14天,内膜明显增厚约为中膜的1.25倍(I/M比1.25±0.14,与七天比,P<0.05),TUNELI逐渐减小(为8.75±4.01;与七天比,P>0.05)。损伤后21天,内膜开始变薄(I/M比为0.98±0.41,与14天比,P<0.05),凋亡水平进一步下降(TUNELI为6.58±3.97,但差异无显著性,P=NS)。结论 血管壁对损伤刺激诱发增生反应的同时激活凋亡机制。凋亡调节血管壁细胞数和内膜增厚演变。细胞凋亡的平衡失调可能是动脉粥样硬化(AS)、再狭窄(RS)等血管疾病发生的机制之一。     

孕激素对卵巢切除大鼠子宫肌层发育的影响

目的　探讨孕激素对卵巢切除大鼠子宫肌层发育的影响。方法　将4 0只幼年大鼠随机分为A、B、C、D组,每组各10只。A组为假手术组,只行开关腹手术;B、C、D组均切除双侧卵巢,其中C组及D组分别加用大剂量及小剂量孕激素。连续给药6周后,测量各组大鼠子宫重量,用HE染色法加计算机图像分析技术观察子宫内膜、肌层及垂体、肾上腺的组织形态学变化。结果　B组子宫重量明显减轻至(14 5 .0 0±31.0 8) mg,C组子宫重量由(14 5 .0 0±31.0 8) mg增至(5 4 0 .30±86 .30 ) mg;肌细胞直径由(4.83±0 .2 5 ) μm增至(16 .5 2±0 .4 6 ) μm,与B、D组比较P均<0 .0 5。各组大鼠垂体及肾上腺无明显组织学改变。结论　大剂量孕激素可促进卵巢切除大鼠子宫肌层的发育。     

辛伐他汀对大鼠平滑肌祖细胞和内皮祖细胞迁移的影响

目的观察辛伐他汀对平滑肌祖细胞(smooth muscle progenitor cell,SPC)和内皮祖细胞(endothelialprogenitor cell,EPC)迁移的影响,筛选新一代包被洗脱支架药物。方法采用密度梯度离心法获取大鼠骨髓单个核细胞,重悬于SPC培养基或EPC培养基,接种在纤维连接素包被培养板,平滑肌肌动蛋白免疫荧光染色鉴定骨髓源性SPC,激光共聚焦显微镜鉴定Dil标记乙酰化低密度脂蛋白(DiI-acLDL)和FITC标记的荆豆凝集素Ⅰ(FITC-UEA-Ⅰ)双染阳性细胞为正在分化的EPC。分别收集培养8 d的SPC和EPC,加入不同浓度辛伐他汀(0,0.01,0.1,1,10μmol/L)培养24 h。采用改良Boyden小室检测SPC和EPC迁移能力。结果辛伐他汀显著抑制SPC迁移,0.01μmol/L辛伐他汀作用24 h,迁移SPC数量减少,0.01μmol/L辛伐他汀组与对照组SPC迁移比较,差异有统计学意义(39±3 vs.44±3,n=5,P0.05)。与SPC相反,辛伐他汀显著促进EPC迁移,其促进作用随辛伐他汀浓度升高而增加,1.0μmol/L时达最大效应,1.0μmol/L辛伐他汀组与对照组EPC计数比较,差异有统计学意义(37±5 vs.6±3,n=5,P0.01)。结论辛伐他汀选择性抑制SPC迁移,促进EPC迁移,其双向调节作用呈浓度依赖性,局部应用有促进损伤血管再内皮化和抑制新内膜过度增生的可能。     

冠状动脉支架术后再狭窄中血管平滑肌细胞表型转换的研究

目的：通过制作猪冠状动脉支架术后再狭窄模型,研究冠状动脉支架内再狭窄时平滑肌细胞表型的变化. 方法：将12只家猪随机分为正常对照组和支架组,每组各6只.正常对照组进行假手术,不做其他处理.支架组家猪于冠状动脉前降支和回旋支各置入裸支架1枚（微创Firebird）.取30 d后经冠状动脉造影确定发生再狭窄的血管段,HE染色观察组织形态;取中层平滑肌细胞培养,电镜观察细胞形态与结构;Western blot测定缝隙连接蛋白（connexin,Cx）43、Cx40、a-平滑肌肌动蛋白（α-SMA）、S100钙结合蛋白A4 （S100A4）的表达. 结果：支架组血管内膜显著增厚,中层平滑肌细胞以长菱形平滑肌细胞（R-SMC）为主,而对照组以纺锤形平滑肌细胞（S-SMC）为主;支架组Cx43、S100A4表达较对照组增强,Cx40、α-SMA表达较对照组降低（P＜0.01）.结论：经皮冠状动脉介入术后S-SMC向R-SMC的转换可能参与了再狭窄过程.     

高压培养对血管平滑肌细胞增殖的影响及机制

目的 研究高压培养对血管平滑肌细胞增殖的影响及机制。方法 利用丝裂素活化蛋白激酶（MAPK)、血小板衍化生长因子（PDGF）和血管紧张素Ⅱ(AngⅡ）生物活性检测，观察高压培养对平滑肌细胞增殖、PDGF和AngⅡ的影响。结果 高压培养促进血管平滑肌细胞增殖，使MAPK活性增加，同时平滑肌细胞分泌PDGF、AngⅡ增加。结论 高压培养促进血管平滑肌细胞增殖，可能是通过促使血管平滑肌细胞分泌PDGF、AngⅡ增加，进而促进MAPK活性增加途径实现的。     

L-精氨酸对低氧性肺动脉高压大鼠肺动脉平滑肌细胞凋亡的影响

目的 探讨L-精氨酸(L-Arg)对低氧性肺动脉高压大鼠不同节段肺动脉平滑肌细胞凋亡的影响。方法 将Wistar大鼠(n=19)随机分为对照组(n=7)、低氧组(n=6)及低氧 L-Arg组(n=6)。经右心导管法测定各组大鼠肺动脉压力和右室(RV)/左室 室间隔(LV S)比值,以分光光度法间接测定血浆一氧化氮(NO)含量,通过TUNEL法检测各组大鼠不同节段的肺动脉平滑肌细胞凋亡数目,并计算肺动脉平滑肌细胞凋亡数目与肺动脉平滑肌细胞数目比值。结果 低氧组大鼠肺动脉平均压(PAMP)显著高于对照组[(2.71±0.29)kPa vs(2.05±0.14)kPa,P<0.01],低氧 L-Arg组大鼠的PAMP显著低于低氧组[(2.23±0.18)kPa vs(2.71±0.29)kPa,P<0.05];低氧组大鼠RV/(LV S)比值显著高于对照组[(0.42±0.03)kPa vs(0.30±0.05)kPa,P<0.01],低氧 L-Arg组大鼠RV/(LV S)比值显著低于低氧组[(0.36±0.02)kPa vs(0.42±0.03)kPa,P<0.01];低氧组大鼠血浆NO含量明显低于对照组[(3.54±0.47)μmol/L vs(4.79±0.17)μmol/L,P<0.05],低氧 L-Arg组大鼠血浆NO含量显著高于低氧组[(5.21±0.26)μmol/L vs(3.54±0.47)μmol/L,P<0.01];低氧组大鼠与终末细支气管伴行的肺动脉和与呼吸细支气管伴行的肺动脉平滑肌细胞凋亡数目与平滑肌细胞数目比值明显低于对照组[(0.051±0.016     

Ultrastructural studies on the phenotypic modulation of human intimal smooth muscle cells

The present study was carried out to clarify the mechanism of intimal thickening at the ostia of celiac and superior mesenteric arteries. The cell components involved in the process were analyzed under electron microscope. Autopsy samples from cases without significant atherosclerotic diseases were examined and the percentages of smooth muscle cells in either synthetic or contractile state, macrophages, and foam cells in the intima of mesenteric and celiac arteries were calculated. Smooth muscle cells in the synthetic state were predominant in the proximal region and those in the contractile state were predominant in the distal region. Few macrophages were present in both regions. The intima in the proximal and distal regions of celiac arteries in autopsy samples was further divided into three layers and the percentages of various smooth muscle cell phenotypes in each layer were calculated and compared in patients at different ages. In the proximal region, the phenotype of the smooth muscle cells changed from the synthetic to the contractile state from the deeper to the superficial layers with the advance of age. In the distal region, the contractile state was dominant regardless of the age. These results suggest that the phenotypic modulation of human intimal smooth muscle cells is reversible dedifferentiation-redifferentiation process; this phenomenon plays an important role in the initiation of atherosclerosis.     

Effect of glycated collagen on proliferation of human smooth muscle cells in vitro

Summary While non-enzymatic glycation of long-lived tissue proteins such as collagen has been implicated in chronic complications of diabetes mellitus, its role in the aetiology of diabetic macroangiopathy has not been elucidated. To test the hypothesis that glycation of collagen abolishes the inhibitory effect of native collagen on the proliferation of human smooth muscle cells, we obtained smooth muscle cells from human gastric arteries and cultured them on dishes coated with glycated or non-glycated collagen. The proliferation of human smooth muscle cells in the presence of 10 % fetal calf serum or platelet derived growth factor-BB (10 ng/ml) was inhibited by type 1 collagen coated on the dishes. Glycation of collagen with glucose 6-phosphate for 7 days abolished the growth-inhibitory effect of native collagen. Succinylation of collagen, which like glycation blocked the lysyl residues in collagen, also abolished the growth-inhibitory effect. Adhesion of human smooth muscle cells to collagen-coated dishes was not affected by glycation of collagen. Addition of glycated albumin to the medium did not affect the growth of human smooth muscle cells on plastic dishes. The inhibition of human smooth muscle cell proliferation by collagen was not reversed by the glycation of collagen in the presence of aminoguanidine. Results suggest that early glycation abolishes the inhibitory effect of collagen on human smooth muscle cell proliferation and may thus participate in the progression of macroangiopathy in diabetes. [Diabetologia (1996) 39: 800–806] Received: 22 August 1995 and in revised form: 19 February 1996