The effects of glucose-induced oxidative stress on growth and extracellular matrix gene expression of vascular smooth muscle cells

Summary Vascular smooth muscle cell (VSMC) dysfunction plays a role in diabetic macrovasculopathy and this may include abnormalities in growth characteristics and the extracellular matrix. As the actual mechanisms by which glucose induces VSMC dysfunction remain unclear, the aim of this study was to assess the potential role of glucose-induced oxidative stress. Porcine aortic VSMCs were cultured for 10 days in either 5 mmol/l normal glucose or 25 mmol/l D-glucose (high glucose). There was evidence of oxidative stress as indicated by a 50 % increase in intracellular malondialdehyde (p < 0.05), increased mRNA expression of CuZn superoxide dismutase and Mn superoxide dismutase (by 51 % and 37 % respectively, p < 0.01) and a 50 % decrease in glutathione in 25 mmol/l D-glucose (p < 0.001). Growth was increased by 25.0 % (p < 0.01). mRNA expression of extracellular matrix proteins (collagens I, III, IV and fibronectin) was not altered by high glucose in these experimental conditions. Repletion of glutathione with N-acetyl L-cysteine (1 mmol/l) in VSMC grown in high glucose was associated with reduction in malondialdehyde and restored growth to that of normal glucose. The water soluble analogue of vitamin E, Trolox (200 μmol/l), reduced malondialdehyde concentrations, but had no effect on glutathione depletion or the increased growth rate seen with high glucose. The addition of buthionine sulphoximine (10 μmol/l) to VSMC cultured in normal glucose reduced glutathione, increased malondialdehyde and increased growth to a similar extent as that found in high glucose alone. These results suggest that thiol status, rather than lipid peroxides, is a key factor in modulating VSMC growth and that mRNA expression of extracellular matrix proteins is not increased in VSMC under conditions of glucose-induced oxidative stress. [Diabetologia (1998) 41: 1210–1219] Received: 26 November 1997 and in revised form: 28 April 1998     

Regulatory role of eicosanoids in extracellular matrix overproduction induced by long-term exposure to high glucose in cultured rat mesangial cells

Summary Accumulation of extracellular matrix in the mesangium and altered renal eicosanoid synthesis are two prominent features of diabetic glomerular disease. We investigated the relationship between eicosanoid and extracellular matrix production in rat mesangial cells cultured under high glucose vs normal glucose conditions. Long-term exposure of rat mesangial cells to high glucose, but not to iso-osmolar mannitol, significantly increased extracellular matrix accumulation and gene expression and transforming growth factor- (TGF-) mRNA levels, and decreased prostaglandin (PG) E₂ synthesis without affecting production of either thromboxane (TX) B₂ or PGF₂, with respect to cells incubated in normal glucose. Addition of exogenous PGE₂ resulted in a dose-dependent reduction of matrix protein and mRNA levels and TGF- gene expression in cells cultured in either normal or high glucose conditions, whereas exposure to exogenous PGF₂ produced a significant increment in matrix production and matrix and TGF- gene expression in cells grown in normal glucose, but only a slight increase in those cultured in high glucose. Stimulation of endogenous endoperoxide metabolism towards PGE₂ and PGF₂ synthesis with FCE-22,178, a drug originally developed as TXA₂ synthase inhibitor, resulted in a dose-dependent decrease in matrix accumulation and matrix and TGF- gene expression which was suppressed by co-incubation with the cyclo-oxygenase inhibitor feno-profen blocking the FCE-22,178-enhanced PG production. In both cell lines, the rate of synthesis of TXA₂ was very low and the selective blockade of its synthesis (by two other TXA₂ synthase inhibitors, OKY-046 and Ridogrel) or action (by the TXA₂ receptor antagonist BM-13,177) did not alter matrix production or TGF- mRNA levels. These results suggest that the cyclo-oxygenase pathway is involved in the regulation of matrix changes induced by high glucose in rat mesangial cells; the reduced production of PGE₂ may enhance the synthesis or potentiate the effect of stimulators of ECM formation such as TGF-, whereas TXA₂ does not appear to be involved. These data also indicate that glucose-enhanced mesangial matrix accumulation may be prevented by exogenous PGE₂ or by drugs capable of increasing endogenous PGE₂ synthesis.Abbreviations AGE Advanced glycosylation end-products - ECM extracellular matrix - PG prostaglandin - RMC rat mesangial cells - TGF- transforming growth factor- - TX thromboxane - Cox cyclo-oxygenase     

硒对大鼠肝细胞和储脂细胞过氧化脂质及细胞外基质的影响

目的 观察微量元素硒（Ｓｅ）对大鼠肝细胞、储脂（Ｉｔｏ）细胞过氧化脂质和细胞外基质（ＥＣＭ）产生的影响。方法 采用原位灌注方法分离大鼠肝细胞和Ｉｔｏ细胞。结果 培养肝细胞、Ｉｔｏ细胞有一定 基础丙二醛（ＭＤＡ）产生和ＥＣＭ分泌。Ｓｅ可提高肝细胞、Ｉｔｏ细胞谷胱甘肽过氧化物酶（ＧＳＨ－Ｐｘ）活性,抑制基础＝ＥＧＥＹＲＮＰＶＳＧＣＸ （＾３Ｈ－Ｐｒｏ）掺篱、３型前胶原（ＰＣⅢ）分泌及Ｉｔｏ细胞透明质酸     

肝纤维化进程中细胞外基质对肝星状细胞的作用及机制研究进展*

肝纤维化是一种肝内弥漫性细胞外基质（ECM）过度沉积的病理过程,且肝星状细胞（HSC）的激活是肝纤维化发生发展的中心环节。本文主要介绍了在肝纤维化进程中ECM各种成分比例、分子结构的改变及其ECM分子空间结构改变对HSC的激活、增殖和凋亡的作用和机制。     

高糖对大鼠胰星状细胞增殖和细胞外基质合成的影响

目的 探讨高糖刺激对大鼠胰星状细胞(pancreatic stellate cell,PSC)增殖和细胞外基质(extracellular matrix,ECM)合成的影响。方法 分离培养大鼠PSC,取传第3～5代细胞,分别用正常葡萄糖(5.6mmol/L葡萄糖)(正常对照)、高葡萄糖(25mmol/L葡萄糖)(高糖组)和甘露醇(5.6mmol/L葡萄糖+19.4mmol/L甘露醇)(等渗对照组)处理5天后,用MTT法、~3H-Thymidine掺入和~3H-Proline掺入法分别检测细胞增殖、DNA合成和总胶原合成,同时用放免法检测细胞培养上清中Ⅲ型前胶原氨基末端多肽(amino-terminal propeptide of type Ⅲ procollagen,P Ⅲ NP)和透明质酸(hyaluronic acid,HA)含量。结果 与等渗对照组比较,高糖组PSC增殖、DNA合成、总胶原合成和细胞上清HA含量均显著增加(P<0.05),但细胞上清P Ⅲ NP含量无显著性差异(P>0.05)。结论 高糖可刺激PSC增殖与胶原合成,参与PSC活化。体内高糖血症可能是PSC活化的机制之一。     

Effects of a preformed extracellular matrix on long-term serum-free bone marrow culture

Summary The extracellular matrix (ECM) produced by the stromal layer plays a key role in the regulation of commitment and differentiation of hematopoietic cells. Long-term bone marrow culture (LTBMC) allows analysis of the stromal microenvironment. Recently, serum-free LTBMC has been described, but the formation of a classical adherent layer was never observed under these conditions. We have evaluated the effect(s) of a chemically well defined ECM on serum-free and serum-dependent LTBMC. In serum-dependent cultures ECM did not induce a significant increase of hematopoiesis. In serum-free conditions, a marked improvement of hematopoiesis was observed, both in terms of CFU-GM and BFU-E yield and in duration of cultures. A confluent stromal layer was observed only in the presence of ECM. The present results indicate that the addition of ECM to serum-free cultures provides a standardized culture condition, while improving progenitor cell recovery and allowing formation of a confluent stromal layer. Moreover, ECM+ LTBMC may provide a model to study the effect(s) of adhesive proteins and hematopoietic growth factors normally present in serum.This work was supported by an AIRC grant and the Program Terapia dei Tumori,Istituto Superiore di Sanità, Rome     

Induction of hematopoietic microenvironment by the extracellular matrix from long-term bone marrow cultures

Summary Extracellular matrix (ECM) plays an important role in the regulation of hematopoiesis. The ECM obtained from murine long-term bone marrow cultures (LTBMCs) induces hematopoietic foci formation within 3 months after implantation under the murine renal capsule. The foci consist of approximately 3×10⁶ hematopoietic cells and function for at least 11 months. The induced stroma contains transplantable precursors capable of transferring a hematopoietic microenvironment to secondary recipients, and is insensitive to the stroma-stimulating factor produced in recipient mice after irradiation. The ECM induces hematopoietic foci formation in chimeras irradiated by a dose which is lethal for most of the stromal precursors. These facts point to the differences observed between bone marrow stromal precursors and mesenchymal cells induced under the renal capsule. The foci contain bone, but its appearance is limited to early stages of foci growth, and depends on the dose of implanted ECM. Bone is not formed when the xenogeneic ECM from nonhematopoietic tissue is used as an inducer. In this case, the foci develop slowly and are observed only to the tenth month after implantation. The data obtained demonstrate a novel function of the ECM in the induction of a hematopoietic microenvironment.     

甘草酸对胰腺星状细胞细胞外基质代谢调节作用的研究

目的观察甘草酸对胰腺星状细胞（PSC）合成分泌Ⅰ型胶原、基质金属蛋白酶（MMP）及其抑制物（TIMP）的影响，探讨其抗胰腺纤维化的作用机制。方法采用组织块培养法分离培养活化的PSC，培养基中添加0、1、2．5、5和10mg／ml不同剂量的甘草酸，培养24h后分别留取上清和细胞。采用放射免疫法测定上清中Ⅰ型胶原含量；明胶酶谱和反式明胶酶谱测定浓缩上清中MMP-2、MMP-9和TIMP1、TIMP-2的表达；RT-PCR测定MMP-2、MMP-9、TIMP-1、TIMP-2和I型胶原mRNA的表达。结果甘草酸可明显抑制PSC中Ⅰ型胶原含量，以5mg／ml时抑制最明显[从（52±10）ng／ml降至（35±8）ng／m1]。明胶酶谱和RT-PCR显示，PSC有MMP-2、MMP-9和TIMP-2基因和蛋白表达，而TIMP-1仅有基因表达。甘草酸可抑制MMP-2和MMP-9蛋白表达，而MMP-9基因表达未受明显抑制；甘草酸对TIMP-1和TIMP-2基因表达无明显作用，对TIMP-2蛋白的表达仅在10mg／ml浓度时有部分抑制。结论甘草酸可能通过抑制Ⅰ型胶原合成、减少MMP-2和MMP-9表达等途径抑制PSC中细胞外基质的代谢。     

细胞外基质促日本血吸虫培养细胞贴壁作用的研究

目的　研究肝、肺生物基质及鼠尾胶三种细胞外基质 (ECM )对日本血吸虫培养细胞的促贴壁作用。方法　灌注法获取 2 1d虫龄的日本血吸虫虫体 ,冷消化法制备细胞悬液 ,将密度为 2× 10 6/ml的细胞悬液分别接种于均匀铺敷三种基质及未铺敷基质 (对照 )的各组培养瓶中进行培养 ,定时计数贴壁细胞数 ,计算贴壁率。结果　随着培养时间从 8h— 4 8h ,各组日本血吸虫细胞的贴壁率逐渐增高 ,4 8h后下降。同一培养时间 ,基质不同 ,细胞的贴壁率不同。培养 4 8h时细胞的贴壁率 ,鼠尾胶组、肝与肺基质组分别为 6 3 2 7%、4 8 95 %、4 5 36 % ;统计学处理发现 ,它们之间差异显著 ;鼠尾胶组与肝、肺基质组比较 ,p <0 0 1;肝与肺基质组之间比较 ,p <0 0 5 ;对照组与各基质组比较 ,均具显著差异 (p <0 0 1)。 结论　ECM对日本血吸虫培养细胞具有明显的促贴壁作用。其中 ,鼠尾胶对日本血吸虫细胞的促贴壁作用最强 ,其次是肝生物基质 ;肺生物基质的促贴壁作用相对较弱 ,但也强于对照组 (p <0 0 1)。     

维生素E对大鼠肝星状细胞增殖及细胞外基质的影响

目的 观察维生素E（VE）对大鼠肝星状细胞（HSC）过氧化脂质和细胞外基质（ECM）产生的影响。方法 采用原位灌注方法分离大鼠HSC。结果 新分离的大鼠HC培养1w时具有增殖和ECM分泌的活性。VE可有效抑制大鼠HSC^3H-胸腺嗜啶（^3H-TdR）、^3H-脯氨酸（^3H-Pro）的掺入和Ⅲ型前胶原（PCⅢ）及透明质酸（HA）的分泌，VE作用后HSC产生丙二醛（MDA）下降，与分泌PCⅢ的抑制呈正相关。结论 VE可抑制大鼠HSC增殖和减少ECM的分泌。     

生长因子及细胞外基质对肝前体细胞体外增殖及分化的影响

目的 明确多种生长因子对胚胎肝脏前体细胞体外增殖分化的影响。方法 用胶原酶从胎龄14．5d SD大鼠胚胎肝脏分离单个细胞，采用^3H-TdR掺入法检测生长因子对胎肝细胞体外增殖的促进作用，并观察生长因子及细胞外基质成分对胎肝干细胞集落形成的影响。采用免疫细胞双标记及G-6-P酶活性测定以检测肝前体细胞表面标记的表达及向成熟肝细胞的分化能力。结果 肝前体细胞在体外培养时显示克隆样生长的特性。促肝细胞生长因子(HGF)、表皮生长因子(EGF)能促进肝前体细胞的增殖，使DNA合成加速，并促进干细胞集落的形成及角蛋白19、白蛋白、G-6-P的表达。转化生长因子α对肝前体细胞的促增殖作用较弱。转化生长因子β对肝前体细胞的增殖起到抑制作用。细胞基质成分Ⅰ型胶原、Ⅳ型胶原、层黏连蛋白能促进肝干细胞集落的形成，而纤维连接蛋白的作用较弱。肝干细胞单克隆增殖需要生长因子及细胞外基质的共同参与，加入新鲜分离胎肝细胞培养液上清液时单细胞增殖较快，于第5天即形成细胞集落。结论 HGF、EGF对肝前体细胞的增殖分化起重要作用，细胞外基质成分亦参与了其增殖分化过程。肝干细胞单克隆培养除需生长因子和细胞外基质外，可能亦有某些造血细胞、间质细胞分泌的因子参与其增殖分化的调控。     

High glucose-induced alterations of extracellular matrix of human skin fibroblasts are not dependent on TSP-1-TGFbeta1 pathway

Elevated glucose level is the main cause of extracellular matrix (ECM) derangement in various tissues in diabetes mellitus. The development of diabetic nephropathy is considered to be dependent on profibrotic cytokine, transforming growth factor-β1 (TGFβ1). Its excessive activation due to the up-regulation of thrombospondin-1 (TSP-1) in mesangial cells exposed to high glucose contributes to ECM accumulation. However, the role of TSP-1–TGFβ1 pathway in the development of glucose-induced imbalance of ECM homeostasis in skin connective tissue is not studied. We investigated the response of human skin fibroblasts to elevated glucose level (11.0 and 30.0 mM) in terms of: (1) the expression and secretion of fibronectin (FN) and plasminogen activator inhibitor-1 (PAI-1); (2) the accumulation of hyaluronic acid (HA) in pericellular matrix and in the conditioned medium; (3) TGFβ1 expression, secretion and activation; (4) TSP-1 expression and secretion. We demonstrated the up-regulation of FN and PAI-1 by elevated glucose and the stimulation of HA accumulation in both cellular compartments. However, we failed to demonstrate the increase of expression, secretion and activation of TGFβ1, and the increase of TSP-1 expression and secretion in fibroblasts exposed to high glucose. These results show that ECM derangement in skin fibroblasts due to high glucose is not determined by TGFβ1 and its activation by TSP-1.     

主动脉夹层的形成和细胞外基质关系的研究进展

主动脉夹层是指在主动脉中层出现退化、变性、坏死等结构异常病变基础上，内膜撕裂，血液进入中层形成假腔，或由于动脉壁滋养血管破裂后导致壁内血肿形成假腔，假腔逐渐扩张发展为夹层。任何致病因素最终都需要通过改变主动脉的自身组织结构发挥作用。细胞外基质异常改变在主动夹层形成和演变中发挥重要作用。本文试就细胞外基质与主动脉夹层关系研究进展做一综述报告。     

吡咯烷二硫代氨基甲酸盐对白介素18诱导肾小球系膜细胞增殖及细胞外基质分泌的影响

目的观察吡咯烷二硫代氨基甲酸盐（PDTC）对白介素18（IL-18）诱导肾小球系膜细胞（MC）增殖及细胞外基质（ECM）分泌的影响及机制。方法MTT法检测MC的增殖情况,ELISA检测Ⅳ型胶原蛋白（CO-Ⅳ）和层黏连蛋白（LN）,免疫细胞化学检测核转录因子-κB（NF-κB）P65的核易位。结果高糖环境下,25μg／L、50μg／L的IL-18作用48h能明显促进MC增殖、CO-Ⅳ和LN的分泌（P〈0．01）,使NF-κBP65激活,50κg／L组更为显著（P〈0．01）。100κmol／L的PDTC能显著抑制IL-18诱导MC增殖作用（P〈0．01）,CO-Ⅳ和LN的分泌以及P65核易位。结论PDTC可能通过NF-κBP65途径抑制IL-18诱导的MC增殖和细胞外基质分泌。     

细胞外基质凝胶支架与嗅鞘细胞体外生物相容性的研究

目的:体外研究细胞外基质凝胶支架与新生大鼠嗅鞘细胞的生物相容性。方法:利用自备的细胞外基质凝胶支架分别建立二维与三维的培养体系,通过免疫荧光技术、倒置相差显微镜观察和MTT法研究嗅鞘细胞在ECM凝胶支架中的形态特点、生长与增殖的情况。结果:本实验观察到在2种培养体系中嗅鞘细胞均生长良好,尤其在三维培养体系中细胞密度和胞体体积大于对照组,支架内嗅鞘细胞与对照组相比展现了更好的形态特征。MTT法检测二维培养体系中实验组与对照组的吸光度值,两者无明显差异(P>0.05)。结论:体外ECM凝胶支架与嗅鞘细胞有良好的生物相容性,由两者构成的三维结构和生物活性的复合体有可能应用于神经组织工程。     

胰淀素诱导人肾小球系膜细胞凋亡

目的:研究胰淀素（amylin) 对人系膜细胞的毒性作用。方法：采用电镜、TUNEL、DNA凝胶电泳和碘化丙啶染色（PI）流式细胞仪分析技术及免疫组化技术，观察amylin对人系膜细胞的作用。结果：光镜和电镜下见细胞体积缩小、梁色质浓梁、致密、边移和凋亡小体形成；TUNEL细胞染色阳性，DNA凝胶电泳出现DNA“梯形”片断；amylin处理48h后，均可见亚二倍体细胞凋亡峰。定量分析示：系膜细胞的凋亡数量与amylin浓度呈剂量依赖性（P＜0．01）。amylin治疗组和对照组乳酸脱氢酶活性细胞释放率无显著性差异（P＞0．05）。结论：amylin对人系膜细胞具有细胞毒性作用，并可诱导系膜细胞的凋亡。amylin诱导人肾小球系膜细胞的凋亡可能是糖尿病肾病患者进行性肾小球硬化和系膜细胞逐渐消失的机制之一。     

Hepatic non-parenchymal cells and extracellular matrix participate in oval cell-mediated liver regeneration

AIM： To elucidate the interaction between non- parenchymal cells, extracellular matrix and oval cells during the restituting process of liver injury induced by partial hepatectomy （PH）. METHODS： We examined the localization of oval cells, non-parenchymal cells, and the extracellular matrix components using immunohistochemical and double immunofluorescent analysis during the proliferation and differentiation of oval cells in N-2- acetylaminofluorene （2-AAF）/PH rat model. RESULTS： By day 2 after PH, small oval cells began to proliferate around the portal area. Most of stellate cells and laminin were present along the hepatic sinusoids in the periportal area. Kupffer cells and fibronectin markedly increased in the whole hepatic Iobule. From day 4 to 9, oval cells spread further into hepatic parenchyma, closely associated with stellate cells, fibronectin and laminin. Kupffer cells admixed with oval cells by day 6 and then decreased in the periportal zone. From day 12 to 15, most of hepatic stellate cells （HSCs）, laminin and fibronectin located around the small hepatocyte nodus, and minority of them appeared in the nodus. Kupffer cells were mainly limited in the pericentral sinusoids. After day 18, the normal liver Iobule structures began to recover.CONCLUSION： Local hepatic microenvironment may participate in the oval cell-mediated liver regeneration through the cell-cell and cell-matrix interactions.     

实验性糖尿病肺细胞外基质免疫组织化学研究

目的 观察糖尿病４周大鼠肺细胞外基质的变化。方法 采用特殊染色,免疫组织化学方法和图像分析技术,了解肺细胞外基质变化。结果 糖尿病肺弹性纤维,胶原纤维和网状纤维增多,增粗;Ⅳ型胶原吾索状或丛状分布于肺泡隔,细支气管基底膜和毛细血管基底膜,图像分析表明,糖尿病肺弹性纤维,胶原纤维,网状纤维、Ⅳ型胶原和层粘连蛋白的着色面积,积分光密度和相对含量均高于对照组。结论 提示糖尿病早期已存在肺细胞外基质异常变     

Effects of fibroblast extracellular matrix calcification on platelet adhesion in vitro

Calcified atherosclerotic lesions are more prone to rupture during angioplasty than non-calcified lesions and are associated with an increased risk of thrombotic complications following angioplasty. This study investigates the possible role of extracellular matrix (ECM) calcification for platelet adhesion. Human cultured fibroblasts (CRL-1635) were subjected to β-glycerophosphate (10 mM) for 10 to 16 days. Calcification was visualized by von Kossa staining and quantified by the O-cresolphthalein complexone method. Adhesion of calcein-labelled platelets was measured by fluorescence microscopy at static conditions and in a parallel-flow chamber at a shear rate of 1000 s^?1. β-glycerophosphate treatment resulted in a marked calcification of the ECM. In parallel, a small, albeit significant increase in platelet adhesion under static conditions was observed. In contrast, at flow conditions, the area covered by thrombi was significantly lower when calcified ECM was used. The number of thrombi was not significantly different which is compatible with a smaller thrombus size. Taken together, it appears unlikely that calcification of atherosclerotic lesions contributes to thrombotic complications by an increased platelet adhesion.