Aspirin inhibits endothelial nitric oxide synthase (eNOS) and Flk-1 (vascular endothelial growth factor receptor-2) prior to rat colon tumour development

2004 ◽  
Vol 106 (1) ◽  
pp. 83-91 ◽  
Author(s):  
Marta ESCRIBANO ◽  
Laura MOLERO ◽  
Antonio LÓPEZ-FARRÉ ◽  
Cynthia ABARRATEGUI ◽  
Carolina CARRASCO ◽  
...  

Formation of blood vessels is a fundamental element in the control of tumour growth in which vascular endothelial growth factor (VEGF) and nitric oxide (NO) have been demonstrated to be involved. Our aim was to analyse whether changes in the expression of endothelial NO synthase (eNOS) and VEGF in colonic tissue could be detected early and even before the identification of colon tumour-associated morphological modifications in azoxymethane-treated rats. We studied further whether aspirin treatment changed these parameters. An increased expression of both eNOS and VEGF in colonic tissue from azoxymethane-treated rats compared with that from control rats was found. Aspirin treatment (10 mg/kg of body weight per day) reduced eNOS expression, but failed to modify the expression of VEGF in the colonic tissue of azoxymethane-treated rats. No evidence of aberrant crypt formation or changes in the number of blood vessels were observed in the colon of any of the animals studied. Expression of the VEGF receptor Flk-1, but not Flt-1, was increased in colonic tissue of azoxymethane-treated rats compared with control rats. The expression of Flk-1 was mainly localized in the epithelial cells, particularly in the lower part of the crypt. Aspirin treatment reduced Flk-1 expression in both control and azoxymethane-treated rats. Caspase-3 activity, which has been considered as an apoptotic index, was almost undetectable in azoxymethane-treated rats. Aspirin treatment stimulated caspase-3 activity. Overexpression of eNOS, VEGF and its receptor Flk-1 occurred early after azoxymethane administration in rat colonic tissue, even before morphological changes associated with tumour generation were observed, and aspirin prevented the overexpression of both eNOS and VEGF receptor Flk-1.

Endocrinology ◽  
2007 ◽  
Vol 148 (10) ◽  
pp. 4734-4744 ◽  
Author(s):  
P. Brownbill ◽  
G. C. McKeeman ◽  
J. C. Brockelsby ◽  
I. P. Crocker ◽  
C. P. Sibley

Vascular endothelial growth factor (VEGF) is an important vasodilator and effector of permeability in systemic blood vessels. Molecular and tissue culture techniques have provided evidence for its placental synthesis and release. Using an in vitro dual-perfusion model of the term placental lobule from normal pregnancy, we report here the relative secretion of total VEGF, soluble VEGF receptor (VEGFR)-1, and free VEGF into the maternal and fetoplacental circulations of the placenta. We tested the hypothesis that VEGF has vasomotor and permeability effects in the fetoplacental circulation of the human placenta, and we examined the broad intracellular pathways involved in the vasodilatory effect that we found. We show that total VEGF is released into the fetal and maternal circulations in a bipolar fashion, with a bias toward maternal side output. Soluble VEGFR-1 was also secreted into both circulations with bias toward the maternal side. Consequently, free VEGF (12.8 ± 2.4 pg/ml, mean ± se) was found only in the fetoplacental circulation. VEGF-165 was found to be a potent vasodilator of the fetoplacental circulation (maximum response: 77% of previous steady-state fetal-side inflow hydrostatic pressure after preconstriction with U46619; EC50 = 71 pm). This vasodilatory effect was mediated by the VEGFR-2 receptor and nitric oxide in a manner-independent of the involvement of prostacyclin and the src-family tyrosine kinases. However, nitric oxide could explain only 50% of the vasodilatory effect. Finally, we measured the permeability of the perfused placenta to inert hydrophilic tracers and found no difference in the presence and absence of VEGF.


2007 ◽  
Vol 27 (12) ◽  
pp. 4541-4550 ◽  
Author(s):  
Koji Taniguchi ◽  
Ri-ichiro Kohno ◽  
Toranoshin Ayada ◽  
Reiko Kato ◽  
Kenji Ichiyama ◽  
...  

ABSTRACT Spred/Sprouty family proteins negatively regulate growth factor-induced ERK activation. Although the individual physiological roles of Spred-1 and Spred-2 have been investigated using gene-disrupted mice, the overlapping functions of Spred-1 and Spred-2 have not been clarified. Here, we demonstrate that the deletion of both Spred-1 and Spred-2 resulted in embryonic lethality at embryonic days 12.5 to 15.5 with marked subcutaneous hemorrhage, edema, and dilated lymphatic vessels filled with erythrocytes. This phenotype resembled that of Syk −/− and SLP-76 −/− mice with defects in the separation of lymphatic vessels from blood vessels. The number of LYVE-1-positive lymphatic vessels and lymphatic endothelial cells increased markedly in Spred-1/2-deficient embryos compared with WT embryos, while the number of blood vessels was not different. Ex vivo colony assay revealed that Spred-1/2 suppressed lymphatic endothelial cell proliferation and/or differentiation. In cultured cells, the overexpression of Spred-1 or Spred-2 strongly suppressed vascular endothelial growth factor-C (VEGF-C)/VEGF receptor (VEGFR)-3-mediated ERK activation, while Spred-1/2-deficient cells were extremely sensitive to VEGFR-3 signaling. These data suggest that Spreds play an important role in lymphatic vessel development by negatively regulating VEGF-C/VEGFR-3 signaling.


2012 ◽  
Vol 32 (5) ◽  
pp. 884-895 ◽  
Author(s):  
Fabricio Simão ◽  
Aline S Pagnussat ◽  
Ji Hae Seo ◽  
Deepti Navaratna ◽  
Wendy Leung ◽  
...  

Resveratrol may be a powerful way of protecting the brain against a wide variety of stress and injury. Recently, it has been proposed that resveratrol not only reduces brain injury but also promotes recovery after stroke. But the underlying mechanisms are unclear. Here, we tested the hypothesis that resveratrol promotes angiogenesis in cerebral endothelial cells and dissected the signaling pathways involved. Treatment of cerebral endothelial cells with resveratrol promoted proliferation, migration, and tube formation in Matrigel assays. Consistent with these pro-angiogenic responses, resveratrol altered endothelial morphology resulting in cytoskeletal rearrangements of β-catenin and VE-cadherin. These effects of resveratrol were accompanied by activation of phosphoinositide 3 kinase (PI3-K)/Akt and Mitogen-Activated Protein Kinase (MAPK)/ERK signaling pathways that led to endothelial nitric oxide synthase upregulation and increased nitric oxide (NO) levels. Subsequently, elevated NO signaling increased vascular endothelial growth factor and matrix metalloproteinase levels. Sequential blockade of these signaling steps prevented resveratrol-induced angiogenesis in cerebral endothelial cells. These findings provide a mechanistic basis for the potential use of resveratrol as a candidate therapy to promote angiogenesis and neurovascular recovery after stroke.


Biochimie ◽  
2001 ◽  
Vol 83 (6) ◽  
pp. 515-522 ◽  
Author(s):  
Kyril Turpaev ◽  
Dmitry Litvinov ◽  
Vera Dubovaya ◽  
Andrey Panasyuk ◽  
Dmitry Ivanov ◽  
...  

Author(s):  
Ayodeji Folorunsho Ajayi ◽  
Busuyi David Kehinde ◽  
Olubodun Micheal Lateef ◽  
Bolaji Aderibigbe Akorede

Objective: Nitric oxide (NO), prostaglandin E2 (PgE2), and vascular endothelial growth factor (VEGF) are fundamental regulators of epithelial restitution and angiogenesis. They play important roles in ulcer healing. Insights into their possible changes during gastric ulcer healing putting age into consideration could give a guide to the proper management of ulcers in the aging population. This study, therefore, examined alterations in the concentrations of PgE2, NO, and VEGF in the gastric mucosa of rats of different ages after induction of ulcer and during healing.Methods: Male Wister rats (aged 3, 6, and 18 months old) were divided into three groups according to their ages. The ulcer was induced using the acetic acid ulcer model. Healing indices studied on days 3, 7, and 14 were the macroscopic dimension of ulcer, stomach tissue concentration of PgE2, NO, and VEGF, with the immunohistochemical expression of VEGF.Results: Outcome of this study showed 100%, 88.36%, and 62.30% area of mucosa healed in 3-, 6-, and 18-month-old rats respectively, on day 14 post-induction of ulcer. PgE2, NO, and VEGF concentrations were inversely proportional to age during healing. Immunohistochemical staining showed that younger rat (3 and 6 months old) had higher expression of VEGF throughout the healing period.Conclusion: It was therefore concluded that the slower rate of healing in older rats could be due to reduced gastroprotection, epithelial restitution, and angiogenesis as age increases.


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