Browsing by Subject "Neovascularization"

Now showing 1 - 7 of 7
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    Angiogenesis index CD105 (Endoglin)-CD31 (PECAM-1) as a predictive factor for invasion and proliferation in intraductal papillary mucinous neoplasm (IPMN) of the pancreas
    (Murcia : F. Hernández, 2010) Tachezy, Michael; Reichelt, Uta; Melenberg, Tanja; Gebauer, Florian; Izbicki, Jacob R.; Kaifi, Jussuf T.
    Background: Intraductal papillary-mucinous neoplasm (IPMN) of the pancreas is an increasingly diagnosed entity since its definition by the World Health Organization in 1996. It has a broad clinical spectrum ranging from benign to malignant tumors. Optimum treatment is controversial and a better understanding of the development of IPMN of the pancreas and identification of potential prognostic factors will help to address this. Angiogenesis plays an elementary role in the development of malignant tumors and may well also be important in the development of IPMN of the pancreas. Therefore we investigated endothelial cell marker CD31 (PECAM-1) and angiogenesis associated marker CD105 (Endoglin) by immunohistochemistry. Methods: Thirty-two cases of surgically resected IPMN were chosen retrospectively and clinical data were obtained. Specimens were stained for proliferation marker (Ki-67), CD31 and CD105 by immunohistochemistry. A CD105/CD31 Angiogenesis ratio (AR) was established to determine the proliferating fraction of endothelial cells. Results: The AR is significantly elevated in invasive IPMN of the pancreas (Mann-Whitney-U Test, p<0.05) and is associated with the Ki-67-labelling-index, demonstrating synergy between tumor-growth and neovascularisation. Invasive IPMN of the pancreas is associated with significantly lower recurrence-free and overall survival. Conclusions: Neovascularisation plays an important role in the tumorigenesis of invasive IPMN of the pancreas, and therefore angiogenesis-associated molecules like CD105 and CD31 might be useful tools as prognostic markers. Furthermore, the results indicate a potential role for adjuvant anti-angiogenic therapies in selected patients with recurring and/or invasive IPMN of the pancreas.
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    Arterial wall neovascularization induced by glycerol
    (F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2001) Díaz Flores, L.; Gutierrez, R.; Valladares, F.; Díaz, M.; Valera, H.; Díaz Flores Jr, L.; Madrid Cuevas, Juan Francisco
    An int e nse a nd sig ni fica nt neo - vascul ari za tion, with numerous capillaries growing into th e med ia laye r o f th e rat femo ra l art e ry, was demonstrated when glycero l was administered into the interstitium be tween the femoral ve in and the femoral a rt e ry. Th e max imum mi c rovasc ul a ri za ti o n was obse rved at days 7 and 9 after glyce rol administration. Afterwards, invo lution of th e majo rit y of the new lyfo rmed microvessels in the art erial wall occurred. Other substances containing glyce rol in their molecul es, such as tri ace tyl-glyce rol and tri butyril-glyce rol, fa il ed to produce significant neovascul ari zation in the medi a laye r of the femora l art ery. Neova cul ariza tion of the art eri al wa ll was preceded by a co nside rab le dec rease in the number of the smooth muscle ce lls, whi ch ex perienced apoptosis and necrobiosis, disappearing in extense areas of the arteri al segment affected by glyce rol. Coinciding with neovascul ariza tion and mi crovascul ar in volu tion, repopul ation of the med ia laye r by smooth mu 'cle cells was observed.
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    Cell contribution of vasa-vasorum to early arterial intimal thickening formation
    (Murcia: F. Hernández, 2007) Díaz-Flores Jr., L.; Gutiérrez, Ricardo; Varela, H.; Valladares, Francisco; Díaz-Flores, Lucio; Madrid Cuevas, Juan Francisco
    In occluded femoral artery segments, intimal thickening occurred and abundant neovascularization from the surrounding microcirculation developed. Under these conditions, the contribution of vasa-vasorum as a source of supplementary population of cells during the early intimal thickening formation was studied. Using a technique that specifically labels venules, predominantly postcapillary venules, a marker-Monastral Blue B-was used as a tracer to follow the pericyte, endothelial cell and monocyte/macrophage lineages. In the first two days of the experiment, the marker was restricted to the wall of the periarterial microcirculation, being incorporated by endothelial cells, pericytes and some monocytes/macrophages crossing the venule walls. Later, the marker continues to be observed in some of the following cells: endothelial cells and pericytes of the newly-formed vessels, fibroblast-like cells, transitional cells between pericytes and fibroblast-like cells, macrophages migrating into the interstitium, myointimal cells and neoendothelial cells of the arterial lumen. These findings provide evidence that, during arterial intimal thickening formation in occluded arterial segments, the periarterial microvascularization contributes, in addition to recruited macrophages, newlyformed endothelial cells and a supplementary population of fibroblast-like cells and myointimal cells.
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    lntraocular neovascularization
    (Murcia : F. Hernández, 1999) Yoshida, A.; Yoshida, S.; Ishibashi, T.; Inomata, H.
    An important character of the eye is transparency, so intraocular neovascularization, which is fragile and likely to result in hemorrhage, would cause a functional disorder of the eye and contribute to loss of vision associated with such diseases as retinopathy of prematurity, diabetic retinopathy, retinal vein occlusion, and age-related macular degeneration. Recently interest in the mechanisms of intraocular neovascularization has increased, and the mechanisms have been gradually elucidated using several in vitro and in vivo angiogenesis models. Blood vessels in the eye are composed of, and surrounded by, various types of cells that produce multiple factors. Neovascularization is regulated by complex interactions among these angiogenic factors, angiostatic factors, and adhesion molecules, and some of these angiogenesis-related molecules have also been suggested as new targets for novel therapeutic agents of intraocular neo-vascularization. This review focuses on in vivo representative angiogenesis models of the corneal pocket model and the model of oxygen-induced retinopathy, and discusses the role of some angiogenesisrelated factors and adhesion molecules in intraocular neovascularization.
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    Participation of angiogenesis from rat femoral veins in the neovascularization of adjacent occluded arteries
    (F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 1998) Díaz Flores, L.; Gutierrez, R.; Valera, H.; Valladares, F.; Rancel, N.; Rodríguez, F.; Madrid Cuevas, Juan Francisco
    The neovascularization of the arterial wall in human and experimental pathology has been demonstrated. The occlusion of the of the rat femoral artery is a suitable model for the study of these angiogenesis processes. Newly formed capillaries growing into the arterial wall have been described in this model. The origin of these ingrowing capillaries has been attribute to the preformed surrounding venules and capillaries. The contribution of the adjacent femoral vein with a supplementary population of vascular sprouts could also be possible. To test this hypothesis in half of the occluded arteries, the adventitia was removed from the side facing the femoral vein. Between 1 and 3 days after surgery several alterations were found both in the endothelial cells and the smooth muscle cells of the tunica media. Between 3 and 6 days, solid or canalized endothelial sprouts were observed arising from the femoral vein. By days 4 and 6, newly formed capillaries grew into the adventitia and tunica media of the femoral artery. Some of them, penetrated the internal elastic lamina. This microvascular penetration from the femoral vein was more prominent in the area of the ostium of the collateral and when the adventitia was removed. Some ingrowing capillaries were in continuity with the endothelial cells of the arterial neointima. At days 7 and 8, regressing capillaries were observed in the neomicrovasculature network between artery and vein, with a selective loss of the smaller vessels. From day 9 onwards, fewer and larger vascular channels were present between the femoral vein and the femoral artery. An arterial neolumen contained what appeared to be circulating "fresh" blood. Quantitatively, the venous neocapillary density increased from days 4 to 6 and then declined significantly by day 8. The arterial neocapillary density increased form days 4 to 8 and declined significantly by day 12. Moreover, both densities were significantly greater when the arterial adventitia was removed. The perfusion with barium solution showed the presence qf the contrast material in the newly formed vessels, the lumen of the femoral vein, and the neolumen of the occluded arterial segment. The present findings indicate that putative angiogenic molecules released form the occluded arterial segment may reach the adjacent wall of the vein inducing neovascularization from it. The vein vascular sprouts are connected to the ingrowing capillaries in the occluded arterial wall and to the neocapillaries form the preexisting pericytic microvasculature. When the arterial adventitia were removed up to 2 times greater vein neocapillary's density was observed suggesting an easily access of the putative angiogenic factors to the vein.
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    Radix Actinidiae chinensis inhibits neovascularization in colorectal cancer and its mechanism
    (2026) Minyuan Chen; Jiante Li; Jieyu Liu; Ziqi Meng; Biología Celular e Histología; Universidad de Murcia, Departamento de Biología Celular e Histología
    Objective. Colorectal cancer is one of the most common cancers worldwide, and its angiogenesis is a key factor in tumor growth and metastasis. Radix Actinidiae chinensis is considered to have antitumor activity in traditional Chinese medicine, but its effect on neovascularization in colorectal cancer has not been clarified. Herein, we aimed to evaluate the effect of different concentrations of Radix Actinidiae chinensis on the neovascularization of colorectal cancer and explore its possible mechanisms. Method. A mouse model of colorectal cancer was established, and mice were randomly divided into control, low-, and high-concentration groups. Then the mice in the experimental group were treated with Radix Actinidiae chinensis, and its effects on neovascularization and tumor growth were evaluated by tumor growth curve tracking, immunohistochemical analysis, vessel density assessment, RT-qPCR, and protein immunoblotting to explore the underlying mechanisms. Results. It was shown that tumor tissues in the high concentration group exhibited significantly slower growth in both mass and volume compared with the low concentration and control groups. Immunohistochemical staining revealed a reduction in the expression of the vascular endothelial marker CD31 in the Radix Actinidiae chinensis treatment group. Moreover, the protein expression levels of vascular markers in tumor tissues showed a slight decrease in the low-concentration group and a marked reduction in the high-concentration group. These findings suggest that angiogenesis in the tumor microenvironment was inhibited in a concentration-dependent manner, with protein expression levels closely mirroring gene expression patterns. Conclusion. The study found that Radix Actinidiae chinensis inhibits neovascularization in a dose dependent manner in a mouse model of colorectal cancer. These results provide experimental support for its potential use as a therapeutic agent against colorectal cancer, suggesting that it may suppress tumor growth and metastasis by inhibiting angiogenesis.
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    The effect of angiotensin II receptor antagonists on diethylstilbestrol-induced vascular changes in the rat anterior pituitary gland: a quantitative evaluation
    (Murcia : F. Hernández, 1996) Pawlikowski, M.; Grochal, M.; Kulig, Andrzej; Zielinski, K.; Stepien, Henryk; Kunert-Radek, J.; Mucha, S.
    The effects if diethylstilbestrol (DES) and of angiotensin I1 (Ang 11) receptor antagonists, such as losartan (selective AT1 receptor antagonist) or PD 123319 (selective AT2 receptor antagonist) on the anterior pituitary microvasculature were studied by means of computer-assisted image analysis. The vascularization was visualized using Selye's method modified by Poely et al. (1964). It was found that DES induced a sharp increase in vessel area, mean vessel diameter and perimeter, whereas mean vessel number was reduced. These DES-induced changes were inhibited by simultaneous administration of losartan. On the other hand, PD 123319 was less effective. These findings suggest an involvement of Ang 11, acting mainly via AT1 receptors, in the mechanism of estrogeninduced vascular changes in the rat anterior pituitary gland.