Increased angiogenesis in chronic idiopathic myelofibrosis: vascular endothelial growth factor as a prominent angiogenic factor

Increased angiogenesis has been suggested to be implicated in the pathogenesis of chronic idiopathic myelofibrosis (CIMF). We hypothesized that vascular endothelial growth factor (VEGF) drives CIMF-associated angiogenesis, and thus, we aimed to determine its expression and biologic impact in newly diagnosed patients. All patients with CIMF diagnosed between 1990 and 2001, for whom adequate bone marrow specimens and clinical data were available, were deemed eligible. Each case was reclassified according to World Health Organization criteria. Microvessel density (MVD), as assessed by CD34 staining, and VEGF expression were examined by standard immunohistochemistry on paraffin-embedded trephine bone marrow biopsy specimens. The cytogenetic phenotype was determined by fluorescence in situ hybridization. Appropriate summary statistics were used for comparisons between groups; survival was calculated using Kaplan-Meier estimates. Parameters found to be of prognostic significance in univariate analysis were verified in a multivariate Cox regression model. Fifty-five patients with CIMF were investigated. With a median of 43 vascular lumina per 0.747 mm(2), patients with CIMF displayed significantly greater MVD than did age-matched controls (n = 10; median MVD, 19; P < .001) with equal distribution between the various fibrosis stages. Moreover, VEGF expression was significantly increased in CIMF (median, 12 cells/0.747 mm(2) versus 1.4 cells/0.747 mm(2); P = .01) and correlated with MVD (P = .001). However, neither MVD nor VEGF expression correlated with cytogenetics or clinical outcome. We conclude that in CIMF, increased MVD is detectable even in early (pre-)fibrotic stages. Moreover, we found significantly elevated VEGF expression correlating with MVD, thus suggesting VEGF to play a prominent angiogenic role and representing a novel potential therapeutic target in CIMF.     

Altered ratios of pro‐ and anti‐angiogenic VEGF‐A variants and pericyte expression of DLL4 disrupt vascular maturation in infantile haemangioma

Infantile haemangioma (IH), the most common neoplasm in infants, is a slowly resolving vascular tumour. Vascular endothelial growth factor A (VEGF‐A), which consists of both the pro‐ and anti‐angiogenic variants, contributes to the pathogenesis of IH. However, the roles of different VEGF‐A variants in IH progression and its spontaneous involution is unknown. Using patient‐derived cells and surgical specimens, we showed that the relative level of VEGF‐A₁₆₅b was increased in the involuting phase of IH and the relative change in VEGF‐A isoforms may be dependent on endothelial differentiation of IH stem cells. VEGFR signalling regulated IH cell functions and VEGF‐A₁₆₅b inhibited cell proliferation and the angiogenic potential of IH endothelial cells in vitro and in vivo. The inhibition of angiogenesis by VEGF‐A₁₆₅b was associated with the extent of VEGF receptor 2 (VEGFR2) activation and degradation and Delta‐like ligand 4 (DLL4) expression. These results indicate that VEGF‐A variants can be regulated by cell differentiation and are involved in IH progression. We also demonstrated that DLL4 expression was not exclusive to the endothelium in IH but was also present in pericytes, where the expression of VEGFR2 is absent, suggesting that pericyte‐derived DLL4 may prevent sprouting during involution, independently of VEGFR2. Angiogenesis in IH therefore appears to be controlled by DLL4 within the endothelium in a VEGF‐A isoform‐dependent manner, and in perivascular cells in a VEGF‐independent manner. The contribution of VEGF‐A isoforms to disease progression also indicates that IH may be associated with altered splicing. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.     

Pathological significance of vascular endothelial growth factor A isoform expression in human cancer

Vascular endothelial growth factor (VEGF) is a highly specific factor for vascular endothelial cells. Five VEGF-A isoforms (splice variants 121, 145, 165, 189 and 206) are generated as a result of alternative splicing from a single VEGF-A gene. These differ in their molecular weights and in biological properties such as their ability to bind to cell-surface heparan sulfate proteoglycans. Deregulated VEGF-A expression contributes to the development of solid tumors by promoting tumor angiogenesis. More specifically, VEGF-A189 expression is related to angiogenesis and prognosis in certain human solid tumors. VEGF-A189 expression is also related to the xenotransplantability of human cancers into immunodeficient mice in vivo. Consequently, inhibition of VEGF-A or VEGF-A189 signaling regulates the development and metastasis of a variety of tumors. This review focuses on recent studies of the mechanisms by which VEGF-A regulates angiogenesis in the cancer stroma and on our recent findings concerning the potential mechanisms of VEGF-A189 expression on tumor growth and metastasis.     

Pseudocowpox virus encodes a homolog of vascular endothelial growth factor

We have identified a gene encoding a homolog of vascular endothelial growth factor (VEGF) in the Pseudocowpox virus (PCPV) genome. The predicted protein shows 27% amino acid identity to human VEGF-A. It also shows 41 and 61% amino acid identity to VEGFs encoded by orf virus (ORFV) strains NZ2 and NZ7, respectively. Assays of the expressed VEGF-like protein of PCPV (PCPV(VR634)VEGF) demonstrated that PCPV(VR634)VEGF is mitogenic for endothelial cells and is capable of inducing vascular permeability. PCPV(VR634)VEGF bound VEGF receptor-2 (VEGFR-2) but did not bind VEGFR-1 or VEGFR-3. These results indicate that PCPV(VR634)VEGF is a biologically active member of the VEGF family which shares with the ORFV-encoded VEGFs a receptor binding profile that differs from those of all cellular members of the VEGF family. It seems likely that the biological activities of PCPV(VR634)VEGF contribute to the proliferative and highly vascularized nature of PCPV lesions.     

Circulating vascular endothelial growth factor concentrations in patients with postmenopausal osteoporosis

Introduction

The role of vascular endothelial growth factor (VEGF) in osteoporosis has not yet been clearly established. Vascular endothelial growth factor is an important part of bone formation. In the literature, although the effects of VEGF on bone metabolism were investigated by different studies, there are very rare studies analysing the association between osteoporosis and VEGF. In the present study, our objective was to investigate serum VEGF concentrations in patients with postmenopausal osteoporosis (PMO) and the correlation of serum VEGF levels and bone mineral density (BMD).

Material and methods

This study was performed on 35 PMO patients, and 30 age-matched healthy controls. Serum VEGF concentrations were measured using a quantitative sandwich enzyme immunoassay technique according to the manufacturer''s instructions. Bone mineral density values were determined by dual energy X-ray absorptiometry (DEXA).

Results

Serum VEGF concentrations were statistically significantly lower in PMO patients than in controls (150 ±65 pg/ml, 260 ±135 pg/ml respectively; p = 0.005). A positive correlation was found between serum VEGF concentrations and BMD values (r = 0.63, p = 0.001).

Conclusions

Vascular endothelial growth factor concentrations were decreased in PMO patients and VEGF may play an important role in bone health.     

甲状腺癌组织中VEGF和VEGF-C的表达及意义

目的　探讨血管内皮生长因子(VEGF)、VEGF- C在甲状腺癌中的表达及其意义。方法　应用免疫组化S P法检测44例甲状腺癌中VEGF、VEGF C的表达情况,并以17例癌旁正常甲状腺组织作对照。结果　VEGF、VEGF- C在甲状腺癌中呈高水平表达(88. 6%、81. 8% )。VEGF表达随癌组织分化程度的减低而增高, 9例死亡病例均为阳性表达;VEGF- C表达随癌组织分化程度的减低而减低,乳头状癌阳性表达(88 .9% )高于其它类型,VEGF- C阳性率在有淋巴结转移组(92. 0% )明显高于无淋巴结转移组(68. 4% ) (P<0. 05)。9例死亡病例中7例为阳性表达,且7例同时VEGF呈阳性表达。结论　VEGF、VEGF- C表达与甲状腺癌病理分型及预后可能有一定关系,VEGF- C与甲状腺癌淋巴结转移密切相关。     

Expression of vascular endothelial growth factor and vascular endothelial growth factor receptors 1 and 2 in invasive breast carcinoma: prognostic significance and relationship with markers for aggressiveness

Dhakal H P, Naume B, Synnestvedt M, Borgen E, Kaaresen R, Schlichting E, Wiedswang G, Bassarova A, Holm R, Giercksky K‐E & Nesland J M
(2012) Histopathology  61, 350–364 Expression of vascular endothelial growth factor and vascular endothelial growth factor receptors 1 and 2 in invasive breast carcinoma: prognostic significance and relationship with markers for aggressiveness Aims: Vascular endothelial growth factor (VEGF), VEGF receptor 1 (VEGFR‐1) and VEGF receptor 2 (VEGFR‐2) play a role in breast cancer growth and angiogenesis. We examined the expression and relationship with clinical outcome and other prognostic factors. Methods and results: Tumour sections from 468 breast cancer patients were immunostained for VEGF, VEGFR‐1, and VEGFR‐2, and their relationships with tumour vascularity, disseminated tumour cells (DTCs) in bone marrow and other clinicopathological parameters were evaluated. VEGF, VEGFR‐1 and VEGFR‐2 immunoreactivities were observed in invasive breast carcinoma cells. VEGF expression was significantly associated with VEGFR‐1 and VEGFR‐2 expression (P < 0.001). High‐level cytoplasmic expression of VEGFR‐1 was associated with significantly reduced distant disease‐free survival (DDFS) (P = 0.017, log‐rank) and breast cancer‐specific survival (BCSS) (P = 0.005, log‐rank) for all patients, and for node‐negative patients without systemic treatment (DDFS, P = 0.03, log‐rank; BCSS, P = 0.009, log‐rank). VEGFR‐1 expression was significantly associated with histopathological markers of aggressiveness (P < 0.05). Significantly reduced survival was observed in DTC‐positive patients as compared with DTC‐negative patients in the combined moderate/high VEGFR‐1 group (P < 0.001 for DDFS and BCSS), and the same was true for DDFS in the moderate VEGFR‐2 group (P = 0.006). Conclusions: High‐level expression of VEGFR‐1 indicates reduced survival. Higher‐level expression of VEGFR‐1 or VEGFR‐2 in primary breast carcinomas combined with the presence of DTC selects a prognostically unfavourable patient group.     

人血管内皮生长因子受体Flt—l胞外配体结合域的筛选及其结构分析

目的 应用酵母双杂交系统筛选人血管内皮生长因子受体Flt－1胞外最小配合结合域。方法 采用PCR技术,从人胎盘cDNA文库扩增出4个截短的Flt-1cDNA,分别含胞外第2、1、－2、2－3和1－3个loop,构建酵母双杂交系统配合表达质粒,并将pGB59／hVEGF165与pGAD424／Flt-ls两两配对转化酵母菌SFY526。采用滤纸法和液体培养法对阳性克隆进行β－半乳糖苷酶活性分析。结果 Flt－1胞外loop2－3与loop1-3的配体结合能力相关不大,loop1-2的结合力较弱,单独第2个loop无配体结合域－2－3loop,这对研制分子量更小、安全性高的可溶性Flt-1片段,开发其在肿瘤、糖尿病性网膜病变等血管生成相关疾病基因治疗中的应用具有重要的指导意义。     

Expression of vascular endothelial growth factor in human gastric carcinomas

Vascular endothelial growth factor (VEGF), also known as vascular permeability factor, is a secreted protein which may play a pivotal role in tumor-associated microvascular angiogenesis and hyperpermeability. The expression of mRNA for VEGF was examined in eight gastric carcinoma cell lines and 30 gastric carcinoma tissues as well as corresponding normal mucosa. All the cell lines expressed VEGF mRNA at various levels that correlated well with the amounts of VEGF secreted into the condition medium. The expression of VEGF mRNA by TMK-1 cells was increased by the treatment of epidermal growth factor (EGF) or interleukin-1α (IL-1α), whereas it was decreased by the treatment of interferon-β (IFN-β). In gastric carcinoma tissues, the level of VEGF mRNA in primary tumors was higher than that in the corresponding normal mucosas in six (46%) of 13 well-differentiated adenocarcinomas and in two (12%) of 17 poorly differentiated adenocarcinomas, respectively. Vessel counts in well-differentiated adenocarcinomas had a tendency to be higher than those in poorly differentiated adenocarcinomas. In well-differentiated adenocarcinomas, the levels of VEGF mRNA expression tended to be higher in carcinomas of advanced stage than in early stage carcinomas. Both in situ mRNA hybridization and immunohistochemistry demonstrated the presence of VEGF expression within the tumor cells. These results suggest that VEGF may confer angiogenesis and progression of human gastric carcinomas, especially of the well-differentiated type.     

食管癌组织中血管内皮生长因子的表达对树突状细胞的影响

目的：研究食管癌组织中血管内皮生长因子（VEGF）的表达对树突状细胞（DC）的影响。方法：对94例食管癌组织采用辣根过氧化物酶（HRP）标记的链霉亲和素-生物素法（LSAB）,分别检测VEGF、S100蛋白的表达水平,并分析VEGF与S100^＋ DC的相关性。结果：食管癌组织中VEGF的表达率为74.46%（70/94）,VEGF的表达与患者的临床分期及癌组织的分化呈正相关（r=0.864,0.803,P〈0.05）。临床分期越晚,病癌组织的分化越低,癌组织内S100^＋ DC的密度越小（r=-0.763,-0.908,P〈0.05）。随着癌组织内VEGF表达量的上升,S-100^＋ DC的密度降低,二者呈负相关（r=-0.817,P〈0.05）。结论：食管癌组织中VEGF的表达可降低S100^＋DC的密度,从而影响机体的免疫功能。     

Angiogenesis in craniopharyngiomas: Microvascular density and tissue expression of the vascular endothelial growth factor (VEGF) and endostatin

Craniopharyngiomas are benign tumors of the sellar region generally associated with endocrine abnormality and often locally aggressive. Several studies have demonstrated that angiogenesis or neovascularization plays an important role in tumoral growth. The microvascular density (MVD) of craniopharyngiomas was determined in tumor tissue samples from a reference neurosurgery center located in southern Brazil using immunohistochemical methods for two endothelial markers, CD34 and CD105 (endoglin). In addition, tissue expression was determined for an angiogenesis stimulatory factor and for one of its inhibitors, the vascular endothelial growth factor (VEGF) and endostatin, respectively. Endothelial cell immunoreactivity for CD34 and CD105 was observed scattered within the stroma. MVD determined using CD105 antigen was significantly lower than the results obtained by using CD34 antigen. There was no association between the two endothelial markers and tumor extension. The epithelial component showed different degrees of immunoreactivity for VEGF and endostatin in all samples analyzed. We were not able to establish a relationship between angiogenesis in craniopharyngiomas and tumor extension with the endothelial markers used in this study. The investigated vascularization stimulatory and inhibitory factors showed no relation with MVD. We believe that CD105 antigen can be a more specific endothelial marker for tumor angiogenesis than CD34 antigen.     

Role of vascular endothelial growth factor during breast cancer

We review the results of experimental and clinical observations on neoangiogenesis in patients with breast cancer. Vascular endothelial growth factor is an important positive regulator of this process. Experiments showed the possibility of using various direct and indirect antiangiogenic means in the therapy of breast cancer, but clinical efficiency of these methods was not proved. Expression of vascular endothelial growth factor can serve as a prognostic criterion in breast cancer. Antiangiogenic preparations should not be used as monotherapy, but as the treatment complementary to standard therapy.     

Propranolol inhibits angiogenesis via down-regulating the expression of vascular endothelial growth factor in hemangioma derived stem cell

Background: Oral propranolol (PRN) has recently been shown to be highly effective for infantile hemangiomas (IHs), and is currently recommended as the first-line treatment of complicated IHs. However, the therapeutic mechanism(s) still remain unclear. Methods: In this study, we tested hemangioma-derived stem cells for expression of vascular endothelial growth factor (VEGF) in vitro and studied the inhibition of VEGF expression. We used PCR, Elisa, Western blotting and immunohistochemistry in vivo and in vitro trial. Results: The study demonstrated that application of PRN at a “normal” concentration equivalent to plasma concentration did not inhibit proliferation or promote apoptosis of hemangioma derived stem cells (HemSCs) isolated from IH patients. PRN suppressed expression of vascular endothelial growth factor (VEGF) and basic Fibroblast Growth Factor (bFGF) in HemSCs in vitro. Morphological, histological and immunohistological improvement were observed in vivo using murine IH model in which HemSCs pre-treated with PRN were implanted into BALB/c-nu mice. In the pre-treated HemSC grafts, mean micro-vessel density (MVD) significantly decreased and protein levels of VEGF markedly decreased, while bFGF was still detectable. Conclusions: The results suggested PRN inhibited angiogenesis via down-regulating the expression of vascular endothelial growth factor in hemangioma derived stem cell. These findings provide critical insight into the potential mechanisms of PRN action on IH.     

血管内皮生长因子在毛囊生物学中的研究现状

血管内皮生长因子(vascular endothelial growth factor,VEGF)又名血管通透性因子(vascular permeability factor,VPF),是重要的血管生成正性调节因子。作为毛乳头细胞的一种自分泌生长因子,其对毛囊的生长亦有重要作用。血管内皮生长因子不仅能促进毛囊的生长,还参与毛囊生长周期的调控。在内皮细胞中,血管内皮生长因子发挥作用主要是通过与其受体的结合,诱导受体二聚体化和自身磷酸化,从而激活胞内信号转导通路,但在毛囊细胞中是否如此,仍需进一步研究。     

Apelin and vascular endothelial growth factor are associated with mobilization of endothelial progenitor cells after acute myocardial infarction

This study was designed to determine the levels of early endothelial progenitor cells(EPCs),apelin,vascu-lar endothelial growth factor(VEGF) and stromal cell-derived growth factor-1(SDF-1) after acute myocardial infarction(AMI),and to investigate the relationships between these cytokines and early EPCs.Early EPCs,de-fined as CD133+,KDR+,and CD34+ cells,were quantified by flow cytometry.The levels of early EPCs and those cytokines in AMI patients were significantly different from those with coronary artery disease or controls(P < 0.05).Plasma apelin levels were inversely correlated with Gensini score and early EPCs(both P < 0.01).Early EPCs,VEGF and SDF-1 showed different patterns of changes in AMI patients during the first 24 h.The trend in the change of early EPCs was proportionally correlated with that of VEGF(P < 0.05).AMI patients exhibited in-creased early EPCs with remarkably decreased apelin levels and enhanced VEGF levels.     

The World Health Organization reference reagent for vascular endothelial growth factor,VEGF165

Preparations of human sequence recombinant vascular endothelial growth factor-165 (VEGF₁₆₅) synthesized in Escherichia coli were formulated and lyophilized at NIBSC. Following evaluation at NIBSC, the first preparation, 01/424, has been distributed since 2002 as a NIBSC research reagent, but shows variation between ampoules in the volume and crystalline appearance of the lyophilized plug. A second preparation, 02/286, was subsequently lyophilized in a different formulation. Preparation 02/286 has now been evaluated in a collaborative study for its suitability to serve as a reference standard, and compared with preparation 01/424, by five laboratories using in vitro bioassays or immunoassays. On the basis of the results reported here, the World Health Organization (WHO) established the preparation coded 02/286 as the WHO reference reagent (RR) for human VEGF₁₆₅, with an assigned unitage of 13,000 units per ampoule. Details on ordering the WHO RR can be found at www.nibsc.ac.uk.