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VEGF Receptor (vegf + receptor)
Selected AbstractsTime course of changes in angiogenesis-related factors in denervated muscleACTA PHYSIOLOGICA, Issue 4 2006A. Wagatsuma Abstract Aim:, Denervation leads to capillary regression in skeletal muscle. To gain insight into the regulation of this process, we investigated the time course of changes in capillary supply and gene expression of angiogenesis-related factors during muscle denervation. Method:, Female mice underwent surgery to transect the sciatic nerve, and then the gastrocnemius muscles were isolated at 12 h, 1, 3, 5, 10, 20, or 30 days after surgery. The capillary supply was assessed by immunohistochemistry using anti-PECAM-1/CD31 antibody. The mRNA levels for angiogenesis-related factors were analysed using a real-time polymerase chain reaction. Results:, We found that the capillary-to-fibre ratio began to decrease 10 days after muscle denervation and decreased by 52% after 30 days. The levels of mRNA for vascular endothelial growth factor (VEGF), its receptors [fms-like tyrosine kinase (Flt-1) and a kinase insert domain-containing receptor/fetal liver kinase-1 (KDR/Flk-1)], angiopoietin-1 and angiopoietin-2 of denervated muscle were immediately down-regulated after 12 h and remained lower than control muscle until 30 days after muscle denervation. The levels of mRNA for the VEGF receptor, neuropilin-1, angiopoietin receptor and Tie-2 decreased within 12,24 h, but returned to near those of control muscle after 10,20 days, and again decreased after 30 days. Conclusions:, These findings suggest that denervation-induced capillary regression may be associated with down-regulation of VEGF and angiopoietin signalling. [source] VEGF signaling is required for the assembly but not the maintenance of embryonic blood vesselsDEVELOPMENTAL DYNAMICS, Issue 3 2002W. Scott Argraves Abstract Here we investigated the importance of vascular endothelial growth factor (VEGF) signaling to the de novo formation of embryonic blood vessels, vasculogenesis, as opposed to the maintenance of blood vessels. We found that antagonizing the activity of the VEGF signaling pathway by using soluble VEGF receptor 1 (sFlt1) or VEGF antibodies inhibited vasculogenesis that occurs in embryos and in cultures of 7.5 days postcoitus prevascular mesoderm. Antagonist treatment resulted in the formation of clusters of endothelial cells not normally observed during vasculogenesis. In contrast, when embryos with established vasculatures or cultures of vascularized mesoderm were treated with sFlt1 or VEGF antibodies, no discernible alterations to the preexisting blood vessels were observed. These observations indicate that, although VEGF signaling is required to promote the mesenchymal to epithelial transition by which angioblasts assemble into nascent endothelial tubes, it is not required by endothelial cells to maintain their organization as an endothelium. © 2002 Wiley-Liss, Inc. [source] Basic fibrobrast growth factor induces the secretion of vascular endothelial growth factor by human aortic smooth muscle cells but not by endothelial cellsEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 10 2003F. Belgore Abstract Background, Endothelial cell dysfunction and smooth muscle cell (SMC) proliferation are major events in atherogenesis. Both cells are a source of growth factors that mediate cellular proliferation and chemotaxis. Inappropriate production of, and/or response to, these growth factors (such as vascular endothelial growth factor, VEGF, and basic fibroblast growth factor (bFGF)) may contribute to atherogenesis and therefore to disease progression. Methods, Production of VEGF and its soluble receptor (sFlt-1) by human SMCs and human umbilical endothelial cells (HUVECs) after stimulation with bFGF were examined by ELISA of cell culture media and by Western blotting. Results, Smooth muscle cells produced significantly more VEGF than HUVECs (P < 0·05) after 24 h of culture with bFGF levels , 0·001 µg mL,1. bFGF induced dose-dependent production of VEGF by SMCs, where maximum production was present in 1 µg mL,1 of bFGF. Conversely, the SMCs produced less sFlt-1 than HUVECs (P < 0·05). However, bFGF induced dose-dependent phosphorylation of Flt1 and another VEGF receptor, KDR, in HUVECs but not SMCs. There was no VEGF or sFLT-1 after 6 h of culture in any dose of bFGF in either type of cell. Conclusions, Differences in the production of VEGF and sFlt-1 by SMCs and HUVECs are consistent with the role of these cells in angiogenesis. Induction of VEGF production and expression by bFGF in these cells indicates that this growth factor may participate in angiogenesis indirectly by the induction of VEGF. The production of sFlt-1 by both cell types is in agreement with the notion that sFlt-1 may be involved in the regulation of VEGF activity. Additionally, the ability of bFGF to induce dose-dependent phosphorylation of KDR in HUVECs highlights the important role of bFGF in VEGF-mediated angiogenic processes. [source] The C-terminus of viral vascular endothelial growth factor-E partially blocks binding to VEGF receptor-1FEBS JOURNAL, Issue 1 2008Marie K. Inder Vascular endothelial growth factor (VEGF) family members play important roles in embryonic development and angiogenesis during wound healing and in pathological conditions such as tumor formation. Parapoxviruses express a new member of the VEGF family which is a functional mitogen that specifically activates VEGF receptor (VEGFR)-2 but not VEGFR-1. In this study, we show that deletion from the viral VEGF of a unique C-terminal region increases both VEGFR-1 binding and VEGFR-1-mediated monocyte migration. Enzymatic removal of O -linked glycosylation from the C-terminus also increased VEGFR-1 binding and migration of THP-1 monocytes indicating that both the C-terminal residues and O -linked sugars contribute to blocking viral VEGF binding to VEGFR-1. The data suggest that conservation of the C-terminal residues throughout the viral VEGF subfamily may represent a means of reducing the immunostimulatory activities associated with VEGFR-1 activation while maintaining the ability to induce angiogenesis via VEGFR-2. [source] Induction of the vascular endothelial growth factor pathway in the brain of adults with fatal falciparum malaria is a non-specific response to severe diseaseHISTOPATHOLOGY, Issue 2 2010Isabelle M. Medana Medana I M, Day N P J, Roberts R, Sachanonta N, Turley H, Pongponratn E, Hien T T, White N J. & Turner G D H (2010) Histopathology,57, 282,294 Induction of the vascular endothelial growth factor pathway in the brain of adults with fatal falciparum malaria is a non-specific response to severe disease Aims:, Pathological or neuroprotective mechanisms in the brain in severe malaria may arise from microvascular obstruction with malaria-parasitized erythrocytes. This study aimed to investigate the role of hypoxia and induction of the vascular endothelial growth factor (VEGF) pathway in the neuropathophysiology of severe malaria. Methods and results:, Immunohistochemistry was performed on post mortem brain tissue sections from 20 cases of severe malaria and examined for the expression of transcriptional regulators of VEGF [hypoxia-inducible factor-1 alpha (HIF-1,), HIF-2,], DEC-1, VEGF, VEGF receptors 1 and 2, and the activated, phosphorylated VEGF receptor 2 (pKDR). HIFs showed limited protein expression and/or translocation to cell nuclei in severe malaria, but DEC-1, which is more stable and regulated by HIF-1,, was observed. There was heterogeneous expression of VEGF and its receptors in severe malaria and non-malarial disease controls. pKDR expression on vessels was greater in malaria cases than in controls but did not correlate with parasite sequestration. VEGF uptake by malaria parasites was observed. Conclusions:, VEGF and its receptor expression levels in severe malaria reflect a non-specific response to severe systemic disease. Potential manipulation of events at the vasculature by the parasite requires further investigation. [source] Immunohistochemical quantification of lymph vessels, VEGF-C and VEGF receptor 3 in human sarcomasHISTOPATHOLOGY, Issue 1 2006N Friedrichs No abstract is available for this article. [source] Modulation of angiogenesis is effective in a model of rheumatoid arthritisJOURNAL OF ANATOMY, Issue 5 2002A. O. Afuwape A feature of rheumatoid arthritis (RA) is prominent hyperplasia of the synovium, which results in an increased distance between the invasive pannus and the existing synovial vasculature. Concomitantly the hyperplastic tissue imposes an augmented metabolic demand on the pre-existing vasculature. As a consequence the synovium in RA becomes hypoxic, resulting in an increased rate of formation of new blood vessels, to supply nutrients and oxygen. Targeting the vasculature in RA is a potential therapeutic approach in RA. VEGF, a key vascular permeability and angiogenic factor, is expressed in RA. In this study we utilised adenovirus expressing the secreted form of the extracellular domain of the Flt-1 VEGF receptor (sFlt-1) to inhibit VEGF in the collagen-induced arthritis (CIA) model, to determine whether blocking the effects of vegf might be an effective treatment for RA. AdvsFlt-1, administered intravenously on the first day of arthritis, significantly suppressed CIA. For example, on d 6 of arthritis the mean increase in paw thickness, which reflects oedema, for untreated and null adenovirus-treated animals was 0.23 ± 0.05 mm and 0.38 ± 0.08, respectively, compared to 0.07 ± 0.05 for AdvsFlt-1-treated mice (P < 0.001 vs. Adv0-treated and untreated mice by 2-way anova). Western blot analyses revealed the presence of a 100-kDa band, corresponding to human sFlt-1, in liver extracts from arthritic mice infected with AdvsFlt-1 at 24 h but not 72 h after infection. This band was absent in liver extracts from Adv0-infected mice and all synovial extracts. Measurement of protein levels by ELISA demonstrated the presence of sFlt-1 in liver, synovium and serum, although levels declined by 72 h post infection. These data suggest efficient but transient expression of sFlt-1. Sera from adenovirus infected mice were found to contain antiviral antibodies and additionally, sera from AdvsFlt-1-infected but not Adv0-infected mice recognised human recombinant sFlt-1. These observations demonstrate that adenoviral mediated delivery of human sFlt-1 leads to transient gene expression and suppression of CIA. This effect is reduced later in the course of disease due to the expression of antiadenovirus as well as antisFlt-1 antibodies. Future studies will assess the effect of combination treatment, using AdvsFlt-1 together with anti-TNF(antibody, to prolong the beneficial effects of VEGF blockade. These results suggest that blocking the pro-angiogenic and permeability action of VEGF may be beneficial for treatment of RA. [source] Increased VEGFR2 expression during human late endothelial progenitor cells expansion enhances in vitro angiogenesis with up-regulation of integrin ,6JOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 5 2007David M. Smadja Abstract In vitro expansion of late endothelial progenitor cells (EPCs) might yield a cell therapy product useful for myocardial and leg ischaemia, but the influence of EPC expansion on the angiogenic properties of these cells is unknown. In the present study, we investigated the effect of in vitro EPC expansion on vascular endothelial growth factor (VEGF) receptor expression. EPCs were obtained from CD34+ cord blood cells and expanded for up to 5 weeks. Real-time quantitative reverse-transcription polymerase chain reaction (RT-PCR) showed that VEGFR2 expression, contrary to VEGFR1 and VEGFR3 expression, was significantly higher on expanded EPCs than on freshly isolated CD34+ cells or on human umbilical vein endothelial cells (HUVECs). Quantitative flow cytometry confirmed that VEGFR2 density on EPCs increased during the expansion process and was significantly higher than on HUVECs. The impact of VEGFR2 increase was studied on the three theoretical steps of angiogenesis, i.e., EPC proliferation, migration and differentiation. VEGFR2 up-regulation had no effect on VEGF-induced cell proliferation, but significantly enhanced EPC migration and pseudotubes formation dependent on integrin ,6 subunit overexpression. In vitro expansion of late EPCs increases the expression of VEGFR2, the main VEGF receptor, with possible implications for EPC-based angiogenic therapy. [source] Vascular endothelial growth factor protects hepatoma cells against oxidative stress-induced cell deathJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 6 2006Shinji Osada Abstract Background:, The aim of the present study was to examine coordination of the vascular endothelial growth factor (VEGF) and VEGF receptor (Flk-1) system and to study control of VEGF expression by oxidative stress, which is considered a model for chronic liver disease. Methods:, Cell viability was determined by test method with 3-[4, 5-dimethylthiazol-2-yl]-2, 5-dephenyl tetrazolium bromide (MTT). Expressions of cellular proteins were evaluated by western blot analysis. Results:, The c-Met tyrosine phosphorylation in PLC/PRF/5 hepatoma cells was increased by treatment with 20 ng/mL hepatocyte growth factor (HGF), and extracellular signal-regulated kinase (ERK) was also activated. Although Flk-1 was phosphorylated in response to VEGF (>50 ng/mL), phosphorylated ERK was not detected at these concentrations. A total of 5.0 and 10 µmol/L hydrogen peroxide (H2O2) caused cell death in a dose-dependent manner after 24 h. On western blot analysis at 1 h with H2O2, rapid phosphorylation of both ERK1/2 and c-Jun NH2 -terminal kinase (JNK) was observed. In the first 6 h, H2O2 induced cell death for 58.4 ± 6.8%, whereas the presence of 100 ng/mL VEGF improved the survival rate to 77.2 ± 4.2%. The VEGF significantly decreased H2O2 -induced cell death after 12 h, whereas HGF (20 ng/mL) did not have a similar effect. When cells were incubated with 5 µmol/L H2O2, expression of VEGF protein was detected. Furthermore, H2O2 -induced phosphorylation of ERK and JNK was also reduced by VEGF (100 ng/mL). In contrast, HGF did not induce phosphorylation of ERK and JNK. Conclusion:, Hepatoma cells might be able to survive under continuous oxidative stress through expression of VEGF. [source] Aspirin and salicylate inhibit colon cancer medium- and VEGF-induced endothelial tube formation: correlation with suppression of cyclooxygenase-2 expressionJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 10 2003M. I. Shtivelband Summary., To determine whether aspirin and salicylate suppress colon cancer cell-mediated angiogenesis, we evaluated the effects of aspirin and sodium salicylate on endothelial tube formation on Matrigel. Aspirin and sodium salicylate concentration-dependently inhibited human endothelial cell (EC) tube formation induced by conditioned medium collected from DLD-1, HT-29 or HCT-116 colon cancer cells. Aspirin and sodium salicylate at pharmacological concentrations were equally effective in blocking tube formation. Neutralizing antivascular endothelial growth factor (VEGF) antibodies blocked colon cancer medium-induced tube formation. VEGF receptor 2 but not receptor 1 antibodies inhibited tube formation to a similar extent as anti-VEGF antibodies. These results indicate that VEGF interaction with VEGF receptor 2 is the primary mechanism underlying colon cancer-induced angiogenesis. Aspirin or sodium salicylate inhibited VEGF-induced tube formation in a concentration-dependent manner comparable to that of inhibition of colon cancer medium-induced endothelial tube formation. It has been shown that cyclooxygenase-2 (COX-2) is pivotal in cancer angiogenesis. We found that colon cancer medium-induced COX-2 protein expression in EC and aspirin or sodium salicylate suppressed the cancer-induced COX-2 protein levels at concentrations correlated with those that suppressed endothelial tube formation. Furthermore, aspirin and sodium salicylate inhibited COX-2 expression stimulated by VEGF. These findings indicate that aspirin and other salicylate drugs at pharmacological concentrations inhibit colon cancer-induced angiogenesis which is correlated with COX-2 suppression. [source] Age-dependent vascular endothelial growth factor expression and angiogenic capability of bladder smooth muscle cells: implications for cell-seeded technology in bladder tissue engineeringJOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 8 2009Joseph Azzarello Abstract Cell seeding technology is commonly used in the field of tissue engineering to enhance the performance of bioscaffolds and promote tissue regeneration. The age of cells used for ex vivo seeding to achieve maximal tissue regeneration has not been defined. Since rapid angiogenesis is the most critical step for tissue graft survival and success, we evaluated passage-dependent vascular endothelial growth factor (VEGF) expression in cultured smooth muscle cells (SMCs) obtained from urinary bladder and endothelial cell response to bladder SMCs. Levels of various VEGF isoforms mRNA expression and total VEGF secretion were determined by a semi-quantitative reverse-transcription polymerase chain reaction (RT-PCR) and an enzyme-linked immunosorbent assay (ELISA) analysis, respectively. In vitro endothelial cell migration in Transwell® and capillary-like tube formation in MatrigelÔ were used to predict the ability of bladder SMCs to promote angiogenesis. VEGF produced by cultured bladder SMCs increased from passages 4 to 7, and decreased from passages 7 to 12 at both mRNA and protein levels. Endothelial cell migration as well as capillary-like tube formation correlated with levels of VEGF expression by bladder SMCs. Pre-incubation of endothelial cells with a VEGF receptor 1/2 inhibitor, SU5416, significantly reduced the number of capillary-like tubes in SMC-endothelial cell MatrigelÔ co-culture, and confirmed the involvement of VEGF in endothelial cell tube formation. Our results demonstrate that cell passage number is related to levels of VEGF production, which may translate to angiogenesis in engineered tissues. Copyright © 2009 John Wiley & Sons, Ltd. [source] Critical roles of VEGF-C-VEGF receptor 3 in reconnection of the collecting lymph vessels in miceMICROCIRCULATION, Issue 7 2008FUMITAKA IKOMI M.D, Ph.D ABSTRACT Molecular mechanisms of reconnection of collecting lymph vessels were analyzed by using murine popliteal prenodal lymph vessels. At 1 and 2 weeks after being divided by cutting the lymph vessel, lymphatic reconnection was frequently observed accompanied by mesh-like lymphatic channels. Electron microscopic study also showed a monolayer of endothelial cells in the newly developed lymph vessels. Smooth muscle markers were immunofluorescently demonstrated in the wall of the new vessels. At 1 week after the procedure of cutting, augmented expressions of VEGF receptors 1, 2 and 3 were found immunohistochemically at the site of the reconnected lymph vessels. The expression of mRNA for VEGF receptor 3 was enhanced at 5 days and 1 week in small pieces of the tissues containing the reconnected lymph vessels, compared with that in the corresponding tissues obtained with sham operated ones. The administration of VEGF-C at the cutting site of the collecting lymph vessel significantly increased the rate of the reconnected lymph vessels, whereas additional treatment with Flt4/Fc chimera protein significantly reduced the rate of the reconnected ones. These results suggest that activation of VEGF-C-VEGF receptor 3 has critical roles in reconnection of the collecting lymph vessels in adult mice. [source] Tumor cell-associated neuropilin-1 and vascular endothelial growth factor expression as determinants of tumor growth in neuroblastomaNEUROPATHOLOGY, Issue 3 2005Karen Marcus We sought to characterize the expression of vascular endothelial growth factor (VEGF) and its receptors in neuroblastoma (NBL) and to correlate the results with N-myc (MYCN) expression and in vivo growth of these tumors. Two representative human-derived NBL cell lines, SK-N-AS (AS) with low and SK-N-DZ (DZ) with a high MYCN copy number, were used for the study. We examined their proliferation, VEGF and VEGF receptor expression in vitro and xenograft tumor growth in vivo. In parallel, human NBL specimens were analyzed for expression of VEGF and neuropilin-1 (NRP-1). DZ cells exhibited a 4-fold higher proliferation rate than AS. In contrast, VEGF protein expression was significantly higher in AS cells. NRP-1 was the only VEGF receptor produced in AS and DZ cells in vitro and in vivo. Both AS and DZ cells formed tumors in athymic mice but AS tumors grew 3.5 times larger than DZ tumors and had larger diameter tumor vessels. VEGF and NRP-1 expression was also demonstrated in human NBL specimens. Our studies indicate that VEGF and VEGF receptor expression in NBL tumor cells are associated with tumor growth and that angiogenic factors may serve as a biological marker together with already established MYCN amplification. [source] Radix Astragali extract promotes angiogenesis involving vascular endothelial growth factor receptor-related phosphatidylinositol 3-kinase/Akt-dependent pathway in human endothelial cellsPHYTOTHERAPY RESEARCH, Issue 9 2009Yi Zhang Abstract Angiogenesis plays an important role in a wide range of physiological processes and many diseases are associated with dysregulation of angiogenesis. Radix Astragali, commonly used in traditional Chinese medicine, is a potential candidate for treating such diseases. However, the biological effects of Radix Astragali on angiogenesis and its underlying mechanisms are yet to be elucidated fully. This study describes the angiogenic effects of Radix Astragali extract (RAE) on human umbilical vein endothelial cells (HUVEC) in vitro. It was shown that RAE treatment stimulated HUVEC to proliferate. A significant increase in migration was observed in RAE-treated HUVEC using the wound healing migration assay. In addition, a significant increase in the number of branching points was observed during endothelial cell capillary formation after RAE treatment. It was shown that RAE enhances vascular endothelial growth factor (VEGF) mRNA expression, and that a specific blocker of VEGF receptor 2 (KDR/Flk) inhibited the RAE-induced HUVEC proliferation. In addition, a decrease in the RAE-induced HUVEC proliferation was observed after treatment with inhibitors of phosphatidylinositol 3-kinase (PI3K), Akt and endothelial nitric oxide synthase (eNOS). Taken together, these data suggest that RAE is a potent stimulator of angiogenesis and that its pro-angiogenic effects involve the VEGF-KDR/Flk and PI3K-Akt-eNOS pathways. Copyright © 2009 John Wiley & Sons, Ltd. [source] Expression of VEGF-C and VEGF-D as Significant Markers for Assessment of Lymphangiogenesis and Lymph Node Metastasis in Non-Small Cell Lung CancerTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 5 2010Yukuan Feng Abstract Vascular endothelial growth factor (VEGF)-C and VEGF-D induce lymphangiogenesis through activation of VEGF receptor 3 (VEGFR-3) and have been implicated in tumor spread to the lymphatic system. Lymph node dissemination critically determines clinical outcome and therapeutic options of patients with non-small cell lung cancer (NSCLC). However, the relationship of VEGF-C, VEGF-D, and lymph node metastasis in cancers, including NSCLC, is still controversial. To evaluate the relationship between lymphangiogenesis and lymph node metastasis, the expression of VEGF-C and VEGF-D in NSCLC tumors were detected by immunohistochemistry and quantitative real-time polymerase chain reaction (QRT-PCR). QRT-PCR revealed that in marginal region VEGF-C and VEGF-D mRNA was significantly higher than in tumor center, and VEGF-D mRNA was also higher than that in peritumoral lung tissue. Immunohistochemically, we observed the same heterogeneous expression of VEGF-C and VEGF-D proteins. The group with high expression of VEGF-C and VEGF-D in marginal region had a higher incidence of lymph node metastasis compared with the group with low expression. Furthermore, the group with high expression of VEGF-D in marginal region had a higher incidence of lymphatic invasion. The group with high peritumoral lymphatic vessel density (LVD) had higher expression of VEGF-C and VEGF-D mRNA compared with the group with low peritumoral LVD. Our studies suggested that the expression of VEGF-C and VEGF-D at invasive edge was significantly associated with lymph node metastasis or lymphatic invasion in patients with NSCLC and may be involved in regulation of lymphangiogenesis and lymph node metastasis in NSCLC. Anat Rec, 2010. © 2010 Wiley-Liss, Inc. [source] A VEGF Trap Inhibits the Beneficial Effect of bFGF on Vasoreactivity in Corporal Tissues of Hypercholesterolemic RabbitsTHE JOURNAL OF SEXUAL MEDICINE, Issue 9 2008Donghua Xie MD ABSTRACT Introduction., Hypercholesterolemia causes a decrease in normal corporal tissue vasoreactivity in a preclinical model of erectile dysfunction. Previous studies have shown that intracorporal injection (ICI) of basic fibroblast growth factor (bFGF) reverses some of the detrimental vasoreactivity effects of hypercholesterolemia and increases vascular endothelial growth factor (VEGF) expression. Aim., We sought to determine whether the beneficial effects of bFGF are VEGF-mediated. Methods., A total of 32 New Zealand white rabbits were fed a 1% cholesterol diet for 6 weeks and randomly divided into four groups (N = 8/group). Group 1 received a 2.5 µg bFGF ICI and 2.5 × 1011 viral particle unit (vpu) of adenovirus encoding ,-galactosidase (Ad,-gal) ICI, 10 days later. Group 2 received a 2.5 µg bFGF ICI and 2.5 × 1011 vpu of adenovirus encoding soluble VEGF receptor (VEGFR) (AdsVEGFR, a VEGF trap) ICI, 10 days later. Group 3 received phosphate buffered saline solution (PBS) ICI and 2.5 × 1011 vpu Ad,-gal ICI, 10 days later. Group 4 received PBS ICI and 2.5 × 1011 vpu AdsVEGFR ICI, 10 days later. Main Outcome Measures., The corpus cavernosum was harvested for vasoreactivity studies 10 days post viral injection. The effective dose of 50% maximum relaxation was determined. VEGF levels were assessed by enzyme-linked immunosorbent assay. Total and phoshorylated Akt and endothelial nitric oxide were analyzed by Western blot. Results., Endothelium-dependent vasoreactivity was significantly greater in Group 1 vs. all other groups. The VEGF trap eliminated the beneficial effects of bFGF on endothelium-dependent vasoreactivity and decreased Akt and nitric oxide phosphorylation. Conclusions., These data demonstrate that VEGF activity contributes much of the therapeutic modulation of bFGF-mediated vasoreactivity in corporal tissue. Xie D, Findley CM, Greenfield JM, Pippen AM, Kontos CD, Donatucci CF, and Annex BH. A VEGF trap inhibits the beneficial effect of bFGF on vasoreactivity in corporal tissues of hypercholesterolemic rabbits. J Sex Med 2008;5:2069,2078. [source] Angiogenesis: now and then,APMIS, Issue 7-8 2004CARLA COSTA Angiogenesis or new blood vessel formation plays an essential role during embryogenesis, adult vascular remodeling and in several pathological disorders, as in tumor development. Although sprouting of blood vessels is the principal angiogenic mechanism, additional ones, such as the recruitment of bone marrow-derived cells, have recently been described. These processes are controlled by several molecules, although members of the VEGF family of angiogenic factors and its receptors seem to be the main mediators. Initially, VEGF receptors were described as endothelial specific; however, further studies have reported their presence in several types of cells of non-endothelial origin, such as tumor cells. This VEGF receptor altered expression has suggested an angiogenesis-independent growth advantage mechanism on certain types of cancers by the generation of autocrine loops. A possible role in tumorigenesis and a potential novel target in cancer therapy have been hypothesized. Detection of other receptors and molecules considered to be angiogenic players has also been observed on tumor cells. Currently, their clinical significance as well as their potential as therapeutic targets for the treatment of certain cancers is being evaluated, having in mind the future development of promising mechanism-based therapies. The aspects mentioned above are the main focus of this review, which aims to throw light on recent findings respecting angiogenesis and novel therapeutic approaches. [source] Analysis of vascular gene expression in arthritic synovium by laser-mediated microdissectionARTHRITIS & RHEUMATISM, Issue 4 2007Atsushi Hashimoto Objective In rheumatoid arthritis (RA), formation of new blood vessels is necessary to meet the nutritional and oxygen requirements of actively proliferating synovial tissue. The aim of this study was to analyze the specific synovial vascular expression profiles of several angiogenesis-related genes as well as CD82 in RA compared with osteoarthritis (OA), using laser-mediated microdissection (LMM). Methods LMM and subsequent real-time polymerase chain reaction were used in combination with immunohistochemical analysis for area-specific analysis of messenger RNA (mRNA) and protein expression of vascular endothelial growth factor (VEGF), VEGF receptor 1 (VEGFR-1), VEGFR-2, hypoxia-inducible factor 1, (HIF-1,), HIF-2,, platelet-derived growth factor receptor , (PDGFR,), PDGFR,, inhibitor of DNA binding/differentiation 2 (Id2), and CD82 in RA and OA synovial microvasculature and synovial lining. Results Expression of Id2 mRNA was significantly lower in RA synovial vessels compared with OA synovial vessels (P = 0.0011), whereas expression of VEGFR-1 was significantly higher in RA (P = 0.0433). No differences were observed for the other parameters. At the protein level, no statistically significant differences were observed for any parameter, although Id2 levels were 2.5-fold lower in RA (P = 0.0952). However, the number of synovial blood vessels and the number of VEGFR-2,expressing blood vessels were significantly higher in RA compared with OA. Conclusion Our results underscore the importance of area-specific gene expression analysis in studying the pathogenesis of RA and support LMM as a robust tool for this purpose. Of note, our results indicate that previously described differences between RA and OA in the expression of angiogenic molecules are attributable to higher total numbers of synovial and vascular cells expressing these molecules in RA rather than higher expression levels in the individual cells. [source] Molecular Changes in Normal Appearing White Matter in Multiple Sclerosis are Characteristic of Neuroprotective Mechanisms Against Hypoxic InsultBRAIN PATHOLOGY, Issue 4 2003Ursula Graumann Multiple sclerosis is a chronic inflammatory disease of the CNS leading to focal destruction of myelin, still the earliest changes that lead to lesion formation are not known. We have studied the geneexpression pattern of 12 samples of normal appearing white matter from 10 post-mortem MS brains. Microarray analysis revealed upregulation of genes involved in maintenance of cellular homeostasis, and in neural protective mechanisms known to be induced upon ischemic preconditioning. This is best illustrated by the upregulation of the transcription factors such as HIF-1, and associated PI3K/Akt signalling pathways, as well as the upregulation of their target genes such as VEGF receptor 1. In addition, a general neuroprotective reaction against oxidative stress is suggested. These molecular changes might reflect an adaptation of cells to the chronic progressive pathophysiology of MS. Alternatively, they might also indicate the activation of neural protective mechanisms allowing preservation of cellular and functional properties of the CNS. Our data introduce novel concepts of the molecular pathogenesis of MS with ischemic preconditioning as a major mechanism for neuroprotection. An increased understanding of the underlying mechanisms may lead to the development of new more specific treatment to protect resident cells and thus minimize progressive oligondendrocyte and axonal loss. [source] Differentiation and expansion of endothelial cells from human bone marrow CD133+ cellsBRITISH JOURNAL OF HAEMATOLOGY, Issue 1 2001Nadia Quirici We report a method of purifying, characterizing and expanding endothelial cells (ECs) derived from CD133+ bone marrow cells, a subset of CD34+ haematopoietic progenitors. Isolated using immunomagnetic sorting (mean purity 90 ± 5%), the CD133+ bone marrow cells were grown on fibronectin-coated flasks in M199 medium supplemented with fetal bovine serum (FBS), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and insulin growth factor (IGF-1). The CD133+ fraction contained 95 ± 4% CD34+ cells, 3 ± 2% cells expressing VEGF receptor (VEGFR-2/KDR), but did not express von Willebrand factor (VWF), VE-cadherin, P1H12 or TE-7. After 3 weeks of culture, the cells formed a monolayer with a typical EC morphology and expanded 11 ± 5 times. The cells were further purified using Ulex europaeus agglutinin-1 (UEA-1)-fluorescein isothiocyanate (FITC) and anti-FITC microbeads, and expanded with VEGF for a further 3 weeks. All of the cells were CD45, and CD14,, and expressed several endothelial markers (UEA-1, VWF, P1H12, CD105, E-selectin, VCAM-1 and VE-cadherin) and typical Weibel,Palade bodies. They had a high proliferative potential (up to a 2400-fold increase in cell number after 3 weeks of culture) and the capacity to modulate cell surface antigens upon stimulation with inflammatory cytokines. Purified ECs were also co-cultivated with CD34+ cells, in parallel with a purified fibroblastic cell monolayer. CD34+ cells (10 × 105) gave rise to 17 951 ± 2422 CFU-GM colonies when grown on endothelial cells, and to 12 928 ± 4415 CFU-GM colonies on fibroblast monolayers. The ECs also supported erythroid blast-forming unit (BFU-E) colonies better. These results suggest that bone marrow CD133+ progenitor cells can give rise to highly purified ECs, which have a high proliferative capacity, can be activated by inflammatory cytokines and are superior to fibroblasts in supporting haematopoiesis. Our data support the hypothesis that endothelial cell progenitors are present in adult bone marrow and may contribute to neo-angiogenesis. [source] Vascular endothelial growth factor is associated with histological instability of carotid plaques,BRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 5 2008D. A. Russell Background: Vascular endothelial growth factor (VEGF) promotes events favouring carotid plaque instability: inflammatory chemoattraction, thrombogenesis, and upregulation of matrix metalloproteinases and cell adhesion molecules. The aim of this study was to assess neovascularization, VEGF and its receptors in high-grade stable and unstable carotid plaques. Methods: Immunohistochemical staining for CD34, VEGF, VEGF receptor (VEGFR) 1 and VEGFR2 was performed in 34 intact carotid endarterectomy specimens, and compared in sections demonstrating maximal histological instability (cap rupture/thinning) or, if stable, maximal stenosis. Results: VEGF staining was increased in 12 unstable compared with 22 stable plaques (median (interquartile range, i.q.r.) plaque score 4·0 (4·0,4·0) versus 3·0 (2·0,3·0); P = 0·002) with upregulation of VEGFR1 (plaque score 4·0 (2·0,4·0) versus 2·0 (1·0,3·0); P = 0·016). In unstable plaques this was associated with increased microvessel density in the cap (median (i.q.r.) 12·1 (4·0,30·0) versus 1·1 (0·0,7·3) microvessels/mm2; P = 0·017) and shoulder regions (7·7 (3·4,21·4) versus 3·1 (0·4,10·8) microvessels/mm2; P = 0·176). Conclusion: Increased VEGF and receptor staining were seen in histologically unstable carotid plaques. Although these differences could reflect cytokine-driven inflammatory events accompanying plaque instability, VEGF and VEGFR1 could be key mediators. Copyright © 2008 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source] Mobilization of endothelial progenitor cells into the circulation in burned patients,BRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 2 2008A. Fox Background: Bone marrow-derived endothelial progenitor cells (EPCs) have been detected in the peripheral blood of patients following thermal injury. EPCs migrate to sites of active neovascularization in response to mediators released after trauma, contributing to wound healing. The aim was to characterize levels and kinetics of EPCs in burned patients, then relate these to key mobilizing factors, vascular endothelial growth factor (VEGF) and the chemokine (C-X-C motif) ligand 12 (CXCL 12), and compare them with those in healthy subjects. Methods: The study included 19 adult patients with superficial or full-thickness burns and 50 blood donor volunteer controls. EPCs, identified by cell surface markers CD45dim/,, CD133+, CD144+ and VEGF receptor 2, were quantified by four-colour flow cytometry. Plasma VEGF and CXCL12 were measured using enzyme-linked immunosorbent assay. Results: Burned patients showed a rapid rise in EPC levels within 24 h, a ninefold increase compared with controls, returning to basal levels by 72 h. Body surface area burned correlated strongly with the degree of mobilization. EPC levels correlated significantly with rises in plasma VEGF and CXCL12. Conclusion: Thermal injury induced a rapid rise in EPCs that was proportional to the extent of the burn and significantly correlated with levels of angiogenic cytokines. Such cytokines may be used to stimulate EPCs as a future therapeutic target in burned patients. Copyright © 2007 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source] Vascular endothelial growth factor, FLT-1, and FLK-1 analysis in a pancreatic cancer tissue microarray,CANCER, Issue 8 2006Gina G. Chung M.D. Abstract BACKGROUND Measures of vascular endothelial growth factor (VEGF) expression in pancreatic cancer typically have been qualitative or semiquantitative. The objective of this study was to use a series of algorithms called AQUA that quantitatively assesses protein expression on tissue microarrays (TMAs) to compare in situ expression of VEGF and its primary receptors, VEGF receptor 1 (FLT-1) and VEGF receptor 1 (FLK-1), on a pancreatic cancer TMA. METHODS TMAs were constructed by arraying 1.5-mm cores from 76 samples of pancreatic adenocarcinoma (1996-2002) that were obtained from the archives of the Yale Department of Pathology. The staining for AQUA was similar to standard immunohistochemistry and involved antigen retrieval and the application of primary antibodies, but with epifluorescence detection. Slides were counterstained with 4,,6-diamidino-2-phenylindole for nuclear visualization and cytokeratin for membrane visualization. The primary antibodies used were VEGF, FLT-1, FLK-1, and cytokeratin. RESULTS Disease stage was highly prognostic for outcome, as expected. Total amounts of VEGF and its receptors were assessed within the tumor mask and were divided into quartiles. Kaplan,Meier survival curves showed that VEGF and FLK-1 were not associated clearly with outcome. However, the expression of FLT-1 was correlated significantly, and the patients who had tumors with the lowest expression FLT-1 levels had the worst survival (P = .0038). In multivariate analysis, FLT-1 expression was an independent prognostic factor for overall survival (P = .0044). CONCLUSIONS VEGF and its 2 principal receptors were expressed to varying degrees in tumors of the pancreas. A significant association was found between low expression of FLT-1 and both poor prognosis and advanced stage, suggesting that tumor expression of this VEGF receptor is a marker of less aggressive disease. Cancer 2006. © 2006 American Cancer Society. [source] Angiogenesis in patients with craniopharyngiomasCANCER, Issue 3 2002Correlation with treatment, outcome Abstract BACKGROUND Craniopharyngiomas are histologically benign epithelial neoplasms of the sellar region that often exhibit aggressive and invasive growth. The authors hypothesized that tumor proliferation, spread, and recurrence are angiogenesis dependent and investigated the significance of vascularization relative to biologic behavior. To the authors' knowledge, angiogenesis for patients with craniopharyngiomas has not been examined to date. METHODS The authors measured microvessel densities in resected, histologically proven craniopharyngiomas using immunostains for CD-34, a monoclonal antibody that selectively recognizes endothelial cells. Both histologic types of craniopharyngiomas, adamantinomatous and papillary, were included in the study. In addition, the cellular distribution of vascular endothelial growth factor (VEGF), a strong stimulator of new vessel formation, was assessed by both immunohistochemistry and in situ hybridization for VEGF receptor 2 (VEGFR-2) mRNA expression. RESULTS Histologically, small numbers of capillaries were identified in temporal stroma but not in their epithelial components. Immunohistochemistry revealed strong, conclusive cytoplasmic immunoreactivity for VEGF in the epithelial cells of both adamantinomatous craniopharyngiomas and papillary craniopharyngiomas. In situ hybridization showed that VEGFR-2 mRNA was expressed widely, not only in neoplastic epithelium but also in capillary endothelium. CONCLUSIONS Tumors with greater microvessel density regrow more frequently compared with tumors that have lower microvessel density, suggesting that the extent of angiogenesis is of prognostic value in patients with craniopharyngioma. VEGFR-2 may act as a key modulator of VEGF activity in endothelial cells and nonendothelial cells, indicating that VEGF plays an important role in the behavior of craniopharyngiomas. Cancer 2002;94:738,45. © 2002 American Cancer Society. DOI 10.1002/cncr.10281 [source] Induction of the vascular endothelial growth factor pathway in the brain of adults with fatal falciparum malaria is a non-specific response to severe diseaseHISTOPATHOLOGY, Issue 2 2010Isabelle M. Medana Medana I M, Day N P J, Roberts R, Sachanonta N, Turley H, Pongponratn E, Hien T T, White N J. & Turner G D H (2010) Histopathology,57, 282,294 Induction of the vascular endothelial growth factor pathway in the brain of adults with fatal falciparum malaria is a non-specific response to severe disease Aims:, Pathological or neuroprotective mechanisms in the brain in severe malaria may arise from microvascular obstruction with malaria-parasitized erythrocytes. This study aimed to investigate the role of hypoxia and induction of the vascular endothelial growth factor (VEGF) pathway in the neuropathophysiology of severe malaria. Methods and results:, Immunohistochemistry was performed on post mortem brain tissue sections from 20 cases of severe malaria and examined for the expression of transcriptional regulators of VEGF [hypoxia-inducible factor-1 alpha (HIF-1,), HIF-2,], DEC-1, VEGF, VEGF receptors 1 and 2, and the activated, phosphorylated VEGF receptor 2 (pKDR). HIFs showed limited protein expression and/or translocation to cell nuclei in severe malaria, but DEC-1, which is more stable and regulated by HIF-1,, was observed. There was heterogeneous expression of VEGF and its receptors in severe malaria and non-malarial disease controls. pKDR expression on vessels was greater in malaria cases than in controls but did not correlate with parasite sequestration. VEGF uptake by malaria parasites was observed. Conclusions:, VEGF and its receptor expression levels in severe malaria reflect a non-specific response to severe systemic disease. Potential manipulation of events at the vasculature by the parasite requires further investigation. [source] Vascular endothelial growth factor (VEGF), VEGF receptors expression and microvascular density in benign and malignant thyroid diseasesINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 4 2007Ala'eddin Jebreel Summary Angiogenesis is critical for the growth and metastatic spread of tumours. Vascular endothelial growth factor (VEGF) is the most potent inducer of neovasculature, and its increased expression has been related to a worse clinical outcome in many diseases. The purpose of this study was to evaluate the relation between VEGF, its receptors (VEGFR-1 and VEGFR-2) and microvessel density (MVD) in thyroid diseases. Immunostaining for VEGF and VEGF receptors was performed in 66 specimens of thyroid tissue, comprising 17 multinodular goitre (MNG), 14 Graves' disease, 10 follicular adenoma, 8 Hashimoto's thyroiditis, 7 papillary carcinoma and 10 normal thyroid specimens. Thyrocyte positivity for VEGF and VEGF receptors was scored 0,3. Immunohistochemistry for CD31, and CD34 on the same sections was performed to evaluate MVD. Immunohistochemical staining of VEGF in thyrocytes was positive in 92% of all the thyroid tissues studied. Using an immunostaining intensity cut off of 2, increased thyrocyte staining was seen in follicular adenoma specimens, MNG and normal thyroids compared with Hashimoto's thyroiditis and Graves' disease (P < 0.05). Similarly, VEGF thyrocyte expression in Graves' disease was less than other pathologies (P < 0.05). VEGFR-1 expression and the average MVD score did not differ between the different thyroid pathologies. VEGF expression was lower in autoimmune pathologies compared to autonomous growth processes. Conversely, both VEGFR-1 and VEGFR-2 were widely expressed in benign and neoplastic thyroid disease, suggesting that the up-regulation of VEGF and not its receptors occurs as tissue becomes autonomous. There was no clear relationship between MVD measurement and thyroid pathology. [source] VEGF in biological controlJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2007Ellen C. Breen Abstract Vascular endothelial growth factor A (VEGF-A) belongs to a family of heparin binding growth factors that include VEGF-B, VEGF-C, VEGF-D, and placental-like growth factor (PLGF). First discovered for its ability to regulate vascular endothelial cell permeability, VEGF is a well-known angiogenic factor that is important for vascular development and maintenance in all mammalian organs. The development of molecular tools and pharmacological agents to selectively inhibit VEGF function and block angiogenesis and/or vascular permeability has led to great promise in the treatment of various cancers, macular degeneration, and wound healing. However, VEGF is also important in animals for the regulation of angiogenesis, stem cell and monocyte/macrophage recruitment, maintenance of kidney and lung barrier functions and neuroprotection. In addition to its role in regulating endothelial cell proliferation, migration, and cell survival, VEGF receptors are also located on many non-endothelial cells and act through autrocrine pathways to regulate cell survival and function. The following review will discuss the role of VEGF in physiological angiogenesis as well as its role in non-angiogenic processes that take place in adult organs. J. Cell. Biochem. 102: 1358,1367, 2007. © 2007 Wiley-Liss, Inc. [source] Vascular endothelial growth factor reduces Fas-mediated acute liver injury in miceJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 7pt2 2008Yoichi Tanaka Abstract Background and Aim:, Fulminant hepatitis is still a fatal liver disease, and no specific treatment for it has been available. Vascular endothelial growth factor (VEGF) is the focus of attention because of its various actions. We investigated the effect of vascular endothelial growth factor (VEGF) on Fas-induced fulminant hepatic failure (FHF). Method:, Male Balb/c mice were treated with an intraperitoneal injection of an anti-Fas antibody (Jo-2 Ab) with or without premedication with intraperitoneally administered human recombinant VEGF. Results:, The serum level of alanine aminotransferase (ALT) was up to 300 times higher that of normal mice following the Jo-2 Ab injection, and histological analysis revealed hepatic injury and massive hepatocyte apoptosis. The VEGF significantly suppressed an elevation in serum ALT levels and hepatocyte apoptosis. Immunohistochemically, VEGF-treated mice showed that Bcl-xL in hepatocytes was strongly expressed. Conclusions:, Since hepatocytes do not express VEGF receptors, we speculated that VEGF acts on sinusoidal endothelial cells (SECs) and promotes production of cytokines such as hepatocyte growth factor in SECs, resulting in reducing apoptosis through an increase expression of Bcl-xL in hepatocytes. We suggest that VEGF has a potent antiapoptotic effect on hepatocytes through cell,cell interaction between SECs and hepatocytes. [source] Detection of vascular endothelial growth factor and its receptor expression in human hepatocellular carcinoma biopsy specimensJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 6 2000Takeshi Shimamura Abstract Background: Vascular endothelial growth factor (VEGF) exerts its actions on the microvasculature, by interacting with specific endothelial cell receptors, and thus, contributes to angiogenesis and growth in many tumours. Methods: Using nested reverse-transcription,polymerase chain reaction, we examined the biopsy specimens of 14 patients with human hepatocellular carcinoma (HCC) and cirrhosis, for the expression of hepatic VEGF, and the VEGF receptors KDR and flt-1. To avoid the influence of hypoxia or ischaemia induced by surgical manipulation, we used biopsy specimens of the liver instead of resected specimens. Results: Vascular endothelial growth factor mRNA expression was detected in the tumour portion of the specimens in 13 of 14 patients (93%), and in the corresponding non-tumour portion of the specimens in eight patients (57%; P = 0.08). No differences were found between the tumour portion and the corresponding non-tumour portion in relative concentrations of VEGF mRNA. However, mRNA expression of the VEGF receptors, KDR and flt-1, was detected in 14 (100%) and 11 (79%) of the tumour portions, respectively, and in four (29%) and five (36%) of the corresponding non-tumour portions, respectively (,2 test: KDR, P < 0.01; flt-1, P = 0.08). The relative concentration of KDR mRNA in the tumour portions was significantly higher than in the non-tumour portions (Mann,Whitney U -test: P < 0.001) but no differences were detected for flt-1. Conclusions: KDR mRNA is significantly overexpressed in HCC lesions and could be associated with the angiogenesis and tumour growth induced by VEGF. [source] Critical roles of VEGF-C-VEGF receptor 3 in reconnection of the collecting lymph vessels in miceMICROCIRCULATION, Issue 7 2008FUMITAKA IKOMI M.D, Ph.D ABSTRACT Molecular mechanisms of reconnection of collecting lymph vessels were analyzed by using murine popliteal prenodal lymph vessels. At 1 and 2 weeks after being divided by cutting the lymph vessel, lymphatic reconnection was frequently observed accompanied by mesh-like lymphatic channels. Electron microscopic study also showed a monolayer of endothelial cells in the newly developed lymph vessels. Smooth muscle markers were immunofluorescently demonstrated in the wall of the new vessels. At 1 week after the procedure of cutting, augmented expressions of VEGF receptors 1, 2 and 3 were found immunohistochemically at the site of the reconnected lymph vessels. The expression of mRNA for VEGF receptor 3 was enhanced at 5 days and 1 week in small pieces of the tissues containing the reconnected lymph vessels, compared with that in the corresponding tissues obtained with sham operated ones. The administration of VEGF-C at the cutting site of the collecting lymph vessel significantly increased the rate of the reconnected lymph vessels, whereas additional treatment with Flt4/Fc chimera protein significantly reduced the rate of the reconnected ones. These results suggest that activation of VEGF-C-VEGF receptor 3 has critical roles in reconnection of the collecting lymph vessels in adult mice. [source] | ||||||||||||||||||||||||||||