scholarly journals The Involvement of Angiotensin Type 1 and Type 2 Receptors in Estrogen-Induced Cell Proliferation and Vascular Endothelial Growth Factor Expression in the Rat Anterior Pituitary

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Hanna Lawnicka ◽  
Dorota Ptasinska-Wnuk ◽  
Slawomir Mucha ◽  
Jolanta Kunert-Radek ◽  
Marek Pawlikowski ◽  
...  

The aim of our study was to examine the involvement of renin-angiotensin system (RAS) in estrogen-induced lactotropes proliferation and vascular endothelial growth factor (VEGF) expression in rat pituitary. The study was performed on Fisher 344 rats underwent 8-day treatment with diethylstilboestrol (DES). The proliferation index (PCNA) and VEGF expression in pituitary sections were estimated using immunohistochemical methods. Treatment with DES increased the number of PCNA-positive cells, VEGF-positive cells, and VEGF-positive blood vessels in pituitary. Stimulatory effect of estrogen on cell proliferation and VEGF expression in blood vessels was attenuated by losartan, PD123319, and captopril. VEGF immunoreactivity in pituitary cells of DES-treated rats was decreased by AT1 antagonist and not changed by AT2 blocker and ACE inhibitor. Our findings suggest the involvement of RAS in DES-induced cell proliferation and VEGF expression in pituitary. Both the AT1 and AT2 receptors appear to mediate the estrogen-dependent mitogenic and proangiogenic effects in rat pituitary.

2002 ◽  
Vol 227 (7) ◽  
pp. 492-499 ◽  
Author(s):  
Danny Cracchiolo ◽  
Jason W. Swick ◽  
Lucy McKiernan ◽  
Erica Sloan ◽  
Supriya Raina ◽  
...  

Long-term (10-week) treatment of Fischer 344 (F344) rats with the synthetic estrogen diethylstilbestrol (DES) increases the level of vascular endothelial growth factor (VEGF) in the pituitary. This is concurrent with the development of a large tumor of the pituitary of F344 rats. A role for VEGF in estrogendependent pituitary tumor growth is also supported by the fact that pituitary VEGF level is not increased by estrogen treatment in rats of the tumor-resistant Brown Norway (BN) strain. However, VEGF is not increased by estrogen treatment in an F1 hybrid of F344 and BN, even though F1 hybrid rats do form pituitary tumors in response to estrogen. Quantitative trait locus (QLT) mapping reveals that control of estrogen-dependent VEGF expression is linked to the Edpm5 QTL, which was previously identified as a QTL for estrogen-dependent pituitary tumor growth. In contrast, the QTL Edpm2-1 and Edpm9-2, which have been shown to each have a significant effect on estrogendependent pituitary mass of a magnitude similar to Edpm5, do not have any effect on VEGF level. Taken together, our results support the association of VEGF expression with growth of the estrogen-Induced rat pituitary tumor, as has been reported by others, but they also indicate that there is significant pathways of growth regulation that are independent of high-level VEGF expression.


Blood ◽  
2002 ◽  
Vol 99 (12) ◽  
pp. 4434-4442 ◽  
Author(s):  
Tatiana V. Byzova ◽  
Corey K. Goldman ◽  
Jurek Jankau ◽  
Juhua Chen ◽  
Gustavo Cabrera ◽  
...  

The capacity of an adenovirus encoding the mature form of vascular endothelial growth factor (VEGF)–D, VEGF-DΔNΔC, to induce angiogenesis, lymphangiogenesis, or both was analyzed in 2 distinct in vivo models. We first demonstrated in vitro that VEGF-DΔNΔC encoded by the adenovirus (Ad-VEGF-DΔNΔC) is capable of inducing endothelial cell proliferation and migration and that the latter response is primarily mediated by VEGF receptor-2 (VEGFR-2). Second, we characterized a new in vivo model for assessing experimental angiogenesis, the rat cremaster muscle, which permits live videomicroscopy and quantitation of functional blood vessels. In this model, a proangiogenic effect of Ad-VEGF-DΔNΔC was evident as early as 5 days after injection. Immunohistochemical analysis of the cremaster muscle demonstrated that neovascularization induced by Ad-VEGF-DΔNΔC and by Ad-VEGF-A165 (an adenovirus encoding the 165 isoform of VEGF-A) was composed primarily of laminin and VEGFR-2–positive vessels containing red blood cells, thus indicating a predominantly angiogenic response. In a skin model, Ad-VEGF-DΔNΔC induced angiogenesis and lymphangiogenesis, as indicated by staining with laminin, VEGFR-2, and VEGFR-3, whereas Ad-VEGF-A165 stimulated the selective growth of blood vessels. These data suggest that the biologic effects of VEGF-D are tissue-specific and dependent on the abundance of blood vessels and lymphatics expressing the receptors for VEGF-D in a given tissue. The capacity of Ad-VEGF-DΔNΔC to induce endothelial cell proliferation, angiogenesis, and lymphangiogenesis demonstrates that its potential usefulness for the treatment of coronary artery disease, cerebral ischemia, peripheral vascular disease, restenosis, and tissue edema should be tested in preclinical models.


2002 ◽  
Vol 28 (1) ◽  
pp. 20-23 ◽  
Author(s):  
L ARTESE ◽  
C RUBINI ◽  
G FERRERO ◽  
M FIORONI ◽  
A SANTINELLI ◽  
...  

2001 ◽  
Vol 168 (3) ◽  
pp. 409-416 ◽  
Author(s):  
SE Dickson ◽  
R Bicknell ◽  
HM Fraser

Vascular endothelial growth factor (VEGF) is essential for the angiogenesis required for the formation of the corpus luteum; however, its role in ongoing luteal angiogenesis and in the maintenance of the established vascular network is unknown. The aim of this study was to determine whether VEGF inhibition could intervene in ongoing luteal angiogenesis using immunoneutralisation of VEGF starting in the mid-luteal phase. In addition, the effects on endothelial cell survival and the recruitment of periendothelial support cells were examined. Treatment with a monoclonal antibody to VEGF, or mouse gamma globulin for control animals, commenced on day 7 after ovulation and continued for 3 days. Bromodeoxyuridine (BrdU), used to label proliferating cells to obtain a proliferation index, was administered one hour before collecting ovaries from control and treated animals. Ovarian sections were stained using antibodies to BrdU, the endothelial cell marker, CD31, the pericyte marker, alpha-smooth muscle actin, and 3' end DNA fragments as a marker for apoptosis. VEGF immunoneutralisation significantly suppressed endothelial cell proliferation and the area occupied by endothelial cells while increasing pericyte coverage and the incidence of endothelial cell apoptosis. Luteal function was markedly compromised by anti-VEGF treatment as judged by a 50% reduction in plasma progesterone concentration. It is concluded that ongoing angiogenesis in the mid-luteal phase is primarily driven by VEGF, and that a proportion of endothelial cells of the mid-luteal phase vasculature are dependent on VEGF support.


Circulation ◽  
1998 ◽  
Vol 98 (20) ◽  
pp. 2108-2116 ◽  
Author(s):  
Mayumi Inoue ◽  
Hiroshi Itoh ◽  
Makiko Ueda ◽  
Takahiko Naruko ◽  
Akiko Kojima ◽  
...  

2009 ◽  
Vol 137 (7-8) ◽  
pp. 379-383 ◽  
Author(s):  
Ana Vidovic ◽  
Gradimir Jankovic ◽  
Dragica Tomin ◽  
Maja Perunicic-Jovanovic ◽  
Irena Djunic ◽  
...  

Introduction. Increased angiogenesis in bone marrow is one of the characteristics of chronic myeloid leukaemia (CML), a clonal myeloproliferative disorder that expresses a chimeric bcr/abl protein. Vascular endothelial growth factor (VEGF) is one of the most potent and a specific regulator of angiogenesis which principally targets endothelial cells and regulates several of their functions, including mitogenesis, permeability and migration. The impact of elevated VEGF expression on the course of chronic myeloid leukaemia is unknown. Objective. The aim of this study was the follow-up of VEGF expression during the course of CML. Methods. We studied VEGF expression of 85 CML patients (median age 50 years, range 16-75 years). At the commencement of the study, 29 patients were in chronic phase (CP), 25 in an accelerated phase (AP), and 31 in the blast crisis (BC). The temporal expression (percentage positivity per 1000 analysed cells) VEGF proteins over the course of CML were studied using the immunohistochemical technique utilizing relevant monoclonal antibodies. It was correlated with the laboratory (Hb, WBC and platelet counts, and the percentage of blasts) and clinical parameters (organomegaly, duration of CP, AP, and BC) of disease progression. Results. The expression of VEGF protein was most pronounced in AP (ANOVA, p=0.033). The level of VEGF expression correlated inversely with the degree of splenomegaly (Pearson, r=-0.400, p=0.011). High expression of VEGF correlated with a shorter overall survival (log rank, p=0.042). Conclusion. Immunohistochemically confirmed significance of the expression of VEGF in dependence of the CML stage could be of clinical importance in deciding on the timing therapy. These data suggest that VEGF plays a role in the biology of CML and that VEGF inhibitors should be investigated in CML.


2002 ◽  
Vol 196 (11) ◽  
pp. 1497-1506 ◽  
Author(s):  
Janice A. Nagy ◽  
Eliza Vasile ◽  
Dian Feng ◽  
Christian Sundberg ◽  
Lawrence F. Brown ◽  
...  

Vascular permeability factor/vascular endothelial growth factor (VPF/VEGF, VEGF-A) is a multifunctional cytokine with important roles in pathological angiogenesis. Using an adenoviral vector engineered to express murine VEGF-A164, we previously investigated the steps and mechanisms by which this cytokine induced the formation of new blood vessels in adult immunodeficient mice and demonstrated that the newly formed blood vessels closely resembled those found in VEGF-A–expressing tumors. We now report that, in addition to inducing angiogenesis, VEGF-A164 also induces a strong lymphangiogenic response. This finding was unanticipated because lymphangiogenesis has been thought to be mediated by other members of the VPF/VEGF family, namely, VEGF-C and VEGF-D. The new “giant” lymphatics generated by VEGF-A164 were structurally and functionally abnormal: greatly enlarged with incompetent valves, sluggish flow, and delayed lymph clearance. They closely resembled the large lymphatics found in lymphangiomas/lymphatic malformations, perhaps implicating VEGF-A in the pathogenesis of these lesions. Whereas the angiogenic response was maintained only as long as VEGF-A was expressed, giant lymphatics, once formed, became VEGF-A independent and persisted indefinitely, long after VEGF-A expression ceased. These findings raise the possibility that similar, abnormal lymphatics develop in other pathologies in which VEGF-A is overexpressed, e.g., malignant tumors and chronic inflammation.


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