The relationship between transforming growth factor-β1, vascular endothelial growth factor,nitric oxide and Hashimoto's thyroiditis

BackgroundHashimoto's thyroiditis (HT) is one of the autoimmune disorders of the thyroid gland. The pathogenesis of HT has not been clearly understood. This study was designed to investigate plasma transforming growth factor-β1 (TGF-β1), vascular endothelial growth factor (VEGF), and nitrate/nitrite (NOx — two end products of nitric oxide [NO] metabolism) in HT.MethodsForty patients diagnosed HT and 40 age- and sex-matched healthy controls were included in the study. TGF-β1 and VEGF levels were measured by ELISA, NOx levels were measured spectrophotometrically.ResultsPlasma TGF-β1 and VEGF were decreased, and NOx increased in HT patients in comparison with controls. There was a significant correlation between TGF-β1 and VEGF, and weak but significant correlation between TGF-β1 and NOx in HT.ConclusionThis study indicates that TGF-β1, VEGF and NO probably have a role in the pathogenesis of Hashimoto's thyroiditis, and development of autoimmunity. Clearly, further studies are necessary to establish the exact mechanism of TGF-β1, VEGF and NO interaction in Hashimoto's thyroiditis.     

Simvastatin stimulates vascular endothelial growth factor production by hypoxia-inducible factor-1alpha upregulation in endothelial cells

OBJECTIVE: Vascular endothelial growth factor (VEGF) is a potent angiogenic factor and plays an important pathophysiological role in the maintenance of tissue structure as well as regeneration after ischemic injury. Three-hydroxy-3methylglutaryl-CoA reductase inhibitors reduce vascular inflammation and induce angiogenesis. This study examined whether simvastatin stimulates VEGF expression in endothelial cells as well as the nature of its underlying mechanism. METHODS AND RESULTS: Simvastatin induced mRNA expression and protein secretion of VEGF in endothelial cells that were reversed by pretreatment with mevalonate and geranylgeranylpyrophosphate but not by farnesylpyrophosphate. Adenovirus-mediated expression of the dominant-negative mutant of RhoA induced VEGF mRNA and protein. Simvastatin increased hypoxia-inducible factor-1alpha (HIF-1alpha) protein level without changing its mRNA expression. Inhibition of RhoA had similar effects to simvastatin on VEGF expression. Inhibition of RhoA caused the translocation of HIF-1alpha to the nuclear fraction. Depletion of HIF-1alpha by RNA interference blocked simvastatin-induced VEGF mRNA expression. CONCLUSIONS: Simvastatin stimulates VEGF expression by RhoA downregulation and HIF-1alpha upregulation in endothelial cells. These data indicate a novel role for RhoA as a negative regulator of HIF-1alpha.     

内皮素-1和血管内皮生长因子及缺氧诱导因子-1在门脉高压性胃病中的作用

目的探讨患者胃黏膜是否有内皮素-1（ET-1）、血管内皮生长因子（VEGF）和缺氧诱导因子-1（HIF-1）在门脉高压性胃病（PHG）血流动力学调节中的意义。方法分别采取PHG、PHT无PHG、正常对照患者胃黏膜标本用免疫组织化学方法分别检测ET-1、VEGF和HIF-1在胃黏膜中的表达。同时测定3组患者的门静脉血流量（portal venous flow,PVF）和脾静脉血流量（spleen venous flow,SVF）。结果 PHG积分与食管静脉曲张程度无相关性（HC=4.782,P〉0.05）。PHG组PVF和SVF水平明显高于正常对照组（P〈0.05）。PHG组胃黏膜中ET-1、VEGF、HIF-1的阳性面积高于正常对照组（P〈0.05）。ET-1、VEGF、HIF-与PHG积分呈正相关（H分别为10.592、10.614、9.852,P〈0.05）。PHG组患者HIF-1阳性表达和VEGF的阳性表达之呈直线相关（Pearson相关数为0.842,P〈0.01）。结论 ET-1、VEGF和HIF-1与PHG的发生发展有相关性。     

反义寡脱氧核苷酸抑制人胶质瘤细胞的血管内皮生长因子(英文)

目的:了解反义VEGF寡脱氧核苷酸(ODN)对人胶质细胞瘤系(A172细胞)VEGF表达的抑制作用。方法:应用半定量PCR、免疫组化方法分别了解细胞内VEGF mRNA和蛋白的变化,并利用ELISA检测培养上清液中VEGF蛋白的含量。结果:A172细胞经反义VEGF ODN作用后VEGF mRNA的表达量明显减少,且随其浓度的增加而明显减少,但其表达量不受正义和错义VEGF ODN的影响。当A172细胞经50μmol·L~(-1)反义VEGF ODN作用后,细胞内及上清液内VEGF蛋白水平较对照显著减少。结论:反义VEGF ODN特异地抑制A172细胞VEGF mRNA和蛋白的表达。     

新型抗溃疡及促进伤口愈合药--重组人角质细胞生长因子-2

重组人角质细胞生长因子-2(rhKGF-2)能与人体上皮细胞内的成纤维细胞生长因子受体(FGFR)结合而发挥生理作用。研究显示，rhKGF-2可特异性地刺激上皮细胞增殖，促进表皮细胞生长和肉芽组织形成，可用于治疗因上皮细胞损伤引起的溃疡，加速伤口的愈合，耐受性好，值得临床推广。     

Fumarranol, a rearranged fumagillin analogue that inhibits angiogenesis in vivo

The fumagillin family of natural products inhibits angiogenesis through the irreversible inhibition of the type 2 methionine aminopeptidase (MetAP2). Herein is reported a novel fumagillin analogue named fumarranol. It is shown that, like fumagillin, fumarranol selectively inhibits MetAP2 and endothelial cell proliferation. It is also active in a mouse model of angiogenesis in vivo. Unlike TNP-470, fumarranol does not covalently bind to MetAP2. Fumarranol may serve as a lead for a new class of angiogenesis inhibitors.     

Fondaparinux: a synthetic heparin pentasaccharide as a new antithrombotic agent

Fondaparinux (Arixtra, Sanofi-Synthélabo/Organon) is the first of a new class of antithrombotic agents distinct from low molecular weight heparins (LMWHs) and heparin. It is a chemically synthetic pentasaccharide mimicking the site of heparin that binds to antithrombin III (AT). It exhibits only factor (F) Xa (FXa) inhibitor activity via binding to AT, which in turn inhibits thrombin generation. In contrast to heparin and LMWH, plasma anti-Xa activity corresponds directly to levels of fondaparinux. It does not release tissue factor pathway inhibitor (TFPI). There is nearly complete bioavailability by the sc. route, rapid onset of action, a prolonged half-life in both iv. and sc. (14 - 20 h) dosing regimens and no metabolism preceding renal excretion. Phase IIb clinical studies have identified a dose of 2.5 mg once-daily for prophylaxis of venous thrombosis. Four Phase III studies (n > 7000) have demonstrated a combined 50% relative risk reduction of venous thromboembolic events in orthopaedic surgery patients in comparison to the LMWH, enoxaparin. Haemmorrhagic complications for fondaparinux were either comparable to or higher than those for LMWH. The activated partial thromboplastin time (aPTT) is not affected by fondaparinux. At present, laboratory monitoring is not recommended. Clinical trials for treatment of established thrombosis, coronary syndromes and adjunct to thrombolytic therapy are in progress.     

Adenosine modulates vascular endothelial growth factor expression via hypoxia-inducible factor-1 in human glioblastoma cells

Hypoxia appears to induce a program which shifts the cellular phenotype toward an increase in extracellular adenosine. Hypoxia-inducible factor-1 (HIF-1) is a key regulator of genes crucial to many aspects of cancer biology. Since in gliomas there is a strong correlation between HIF-1alpha expression, tumor grade and tumor vascularization, the aim of this study was to investigate whether adenosine may regulate HIF-1 in human glioblastoma cell lines. The results indicate that in the human hypoxic A172 and U87MG glioblastoma cell lines adenosine up-regulates HIF-1alpha protein expression via the A(3) receptor subtype. In particular, we investigated the effect of A(3) receptor antagonists on HIF-1 and vascular endothelial growth factor (VEGF) expression. We found that A(3) antagonists inhibit adenosine-induced HIF-1alpha and VEGF protein accumulation in the hypoxic cells. Investigations in the molecular mechanism showed that A(3) receptor stimulation activates p44/p42 and p38 MAPKs that are required for A(3)-induced increase of HIF-1alpha and VEGF. Further studies are required to demonstrate the in vivo relevance of these observations with regard to the proposed role for adenosine as a key element in hypoxia and in tumors.     

Fondaparinux: a synthetic heparin pentasaccharide as a new antithrombotic agent

Fondaparinux (Arixtra^®, Sanofi-Synthélabo/Organon) is the first of a new class of antithrombotic agents distinct from low molecular weight heparins (LMWHs) and heparin. It is a chemically synthetic pentasaccharide mimicking the site of heparin that binds to antithrombin III (AT). It exhibits only factor (F) Xa (FXa) inhibitor activity via binding to AT, which in turn inhibits thrombin generation. In contrast to heparin and LMWH, plasma anti-Xa activity corresponds directly to levels of fondaparinux. It does not release tissue factor pathway inhibitor (TFPI). There is nearly complete bioavailability by the sc. route, rapid onset of action, a prolonged half-life in both iv. and sc. (14 - 20 h) dosing regimens and no metabolism preceding renal excretion. Phase IIb clinical studies have identified a dose of 2.5 mg once-daily for prophylaxis of venous thrombosis. Four Phase III studies (n > 7000) have demonstrated a combined 50% relative risk reduction of venous thromboembolic events in orthopaedic surgery patients in comparison to the LMWH, enoxaparin. Haemmorrhagic complications for fondaparinux were either comparable to or higher than those for LMWH. The activated partial thromboplastin time (aPTT) is not affected by fondaparinux. At present, laboratory monitoring is not recommended. Clinical trials for treatment of established thrombosis, coronary syndromes and adjunct to thrombolytic therapy are in progress.     

Oxidized low-density lipoprotein inhibits vascular endothelial growth factor-induced endothelial progenitor cell differentiation

1. Bone marrow-derived endothelial progenitor cells (EPC) in the peripheral blood of adult animals and humans have been shown to be incorporated into neovascularization. In contrast, hypercholesterolaemia impairs angiogenesis and collateral vessel formation in response to regional tissue ischaemia. We investigated whether oxidized LDL (oxLDL) affected human EPC differentiation. 2. When isolated human mononuclear cells (MNC) were incubated with vascular endothelial growth factor (VEGF), the number of differentiated, adherent EPC, as assessed by an in vitro culture assay, was increased in a dose-dependent manner (P < 0.01). When MNC were incubated with oxLDL at 1, 5 and 10 microg/mL in the presence of 100 ng/mL VEGF for 24 h, oxLDL dose-dependently reduced the number of differentiated, adherent EPC. 3. Vascular endothelial growth factor-induced EPC differentiation was significantly inhibited by pharmacological phosphatidylinositol 3-kinase blockers (either 10 nmol/L wortmannin or 10 micromol/L LY294002). Interestingly, immunoblotting analysis revealed that oxLDL dose-dependently led to dephosphorylation and, thus, deactivation of Akt in the presence of VEGF. Finally, these inhibitory effects induced by oxLDL were abolished by pretreatment with 1 micromol/L atorvastatin (P < 0.01). 4. Our data indicate that oxLDL inhibits VEGF-induced EPC differentiation through the dephosphorylation of Akt.     

Phosphatidylinositol inhibits vascular endothelial growth factor-A--induced migration of human umbilical vein endothelial cells

Phosphatidylinositol (PI), a phospholipid in component of cell membranes, is widely distributed in animals, plants, and microorganisms. Here, we examined in vitro whether PI inhibits the angiogenesis induced by vascular endothelial growth factor-A (VEGF-A). PI concentration-relatedly and significantly (at 10 and 30 microg/ml) inhibited VEGF-A-induced tube formation in a co-culture of human umbilical vein endothelial cells (HUVECs) and fibroblasts. PI also inhibited the migration, but not proliferation, induced in HUVECs by VEGF-A. Furthermore, PI at 30 microg/ml inhibited the VEGF-A-induced phosphorylation of serine/threonine protein kinase family protein kinase B (Akt) and p38 mitogen activate kinase (p38MAPK), key molecules in cell migration, but not phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), a key molecule in cell proliferation. These findings indicate that PI inhibits VEGF-induced angiogenesis by inhibiting HUVECs migration and that inhibition of phosphorylated-Akt and -p38MAPK may be involved in the mechanism. Therefore, PI may be expected to prevent some diseases caused by angiogenesis.     

链霉素及H7对机械牵张离体心肌HIF-1α、VEGF的影响及机制探讨

目的研究链霉素及H7对机械牵张大鼠心肌组织低氧诱导分子-1α和血管内皮细胞生长因子表达的影响,并探讨二者在其中的作用机制。方法采用大鼠离体灌流心脏模型,膨胀左心室30min,RT-PCR法检测左室心肌细胞HIF-1α、VEGF mRNA的表达,免疫组化观察二者在心肌细胞中定位,Western blot检测HIF-1α蛋白的表达,利用链霉素作为牵张敏感离子通道(SACs)阻断剂研究SACs和PKC抑制剂H7在其中的可能作用。结果与不牵张组HIF-1α和VEGF mRNA无表达的比较,牵张可以明显增加HIF-1α和VEGF mRNA的表达(P<0·05或P<0·01);而链霉素、H7可以明显减少HIF-1α和VEGF mRNA的表达(P<0·05);但是二者不能完全抑制急性牵张刺激激活的HIF-1α和VEGF mRNA水平升高(P<0·05),HIF-1α和VEGF在胞质和胞核中均有表达,并检测到HIF-1α蛋白表达。结论链霉素、H7对膨胀左室致HIF-1α、VEGF表达有明显抑制作用,提示心室膨胀经SACs-PKC-激活胞内信号诱导HIF-1α、VEGF表达。同时链霉素并不能完全抑制HIF-1α、VEGF表达,提示膨胀心室致HIF-1α、VEGF表达进而引起心室肥厚尚有其他传导途径,仍需进一步研究。     

生长抑素类似物抑制胆管癌细胞增殖的研究

目的探讨生长抑素类似物奥曲肽(OCT)对人胆管癌细胞细胞株QBC939的抑制作用及可能的作用机制。方法四氮唑蓝(MTT)法检测OCT对人胆管癌细胞株QBC939增殖的影响,流式细胞仪检测OCT对细胞周期变化的作用,免疫组织化学法研究OCT对人胆管癌细胞株QBC939P27KIP1蛋白表达变化的影响。建立胆管癌裸鼠模型,进一步探讨生长抑素的作用。结果MTT法检测不同浓度OCT(5、0.5、0.05、0.005mg/L)作用于QBC93948h后,实验组0.5、5mg/L组和对照组吸光度(A)值比较差异有统计学意义(P<0.05)。细胞生长率分别为83.80%,80.28%,77.53%,65.32%。流式细胞仪分析显示不同浓度OCT作用于QBC93948h后,G0/G1期细胞明显增多(P<0.05)。免疫组织化学P27KIP1蛋白表达随OCT浓度的增加而增强(P<0.05)。建立胆管癌裸鼠模型后,OCT干预21d后实验组瘤重明显小于对照组(P<0.05)。结论OCT可抑制人胆管癌细胞的增殖。在一定范围内呈剂量依赖性,其抗肿瘤作用机制主要是通过细胞周期阻滞来实现的,而这一作用的实现可能与P27KIP1蛋白表达的上调有关。     

Disposition of sandostatin, a new synthetic somatostatin analogue, in rats

The distribution, excretion, and metabolism of Sandostatin, a long-acting octapeptide analogue of somatostatin, have been studied in the rat after iv administration. Similar plasma levels and excretion values were observed by using radioimmunoassay and HPLC-liquid scintillation techniques. For the latter technique Sandostatin was radiolabeled with either 14C or 3H. The plasma pharmacokinetics of Sandostatin were as follows: Vdss = 0.4 liter/kg, C/t = 4.2 ml/min, and t1/2 2.0 hr; this half-life was by far longer than that of somatostatin. The in vitro protein binding amounted to 59% in rat plasma; no Sandostatin was taken up by blood cells. The tissue concentrations of Sandostatin were similar when determined either by radioimmunoassay or by quantitative whole-body autoradiography; this suggests that the distribution of 3H or 14C radioactivity observed 0.5 hr after iv administration mostly represented unchanged Sandostatin. Kidney and liver were the only tissues in which Sandostatin levels were higher than in blood; high radioactivity levels were observed in the blood vessel walls, whereas levels in brain were insignificant. Unchanged drug accounted for most of the radioactivity found in plasma, urine, and bile, whereas only traces of unchanged drug were detected in feces. These results demonstrated the metabolic stability of Sandostatin in the tissues, primarily in the liver, and suggested an extensive degradation in the intestinal tract. The degradation products consisted of smaller peptides and free amino acids. About 50% and 20% of the applied dose were excreted as unchanged Sandostatin in bile and urine, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Design, synthesis, and evaluation of orally active benzimidazoles and benzoxazoles as vascular endothelial growth factor-2 receptor tyrosine kinase inhibitors

Inhibition of the VEGF signaling pathway has become a valuable approach in the treatment of cancers. Guided by X-ray crystallography and molecular modeling, a series of 2-aminobenzimidazoles and 2-aminobenzoxazoles were identified as potent inhibitors of VEGFR-2 (KDR) in both enzymatic and HUVEC cellular proliferation assays. In this report we describe the synthesis and structure-activity relationship of a series of 2-aminobenzimidazoles and benzoxazoles, culminating in the identification of benzoxazole 22 as a potent and selective VEGFR-2 inhibitor displaying a good pharmacokinetic profile. Compound 22 demonstrated efficacy in both the murine matrigel model for vascular permeability (79% inhibition observed at 100 mg/kg) and the rat corneal angiogenesis model (ED(50) = 16.3 mg/kg).