Browsing by Subject "Microcirculation"

Now showing 1 - 4 of 4
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    Cerebrovascular pathophysiology of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2021) Suzuki, Hidenori; Kanamaru, Hideki; Kawakita, Fumihiro; Asada, Reona; Fujimoto, Masashi; Shiba, Masato
    Aneurysmal subarachnoid hemorrhage (SAH) remains a serious cerebrovascular disease. Even if SAH patients survive the initial insults, delayed cerebral ischemia (DCI) may occur at 4 days or later post-SAH. DCI is characteristics of SAH, and is considered to develop by blood breakdown products and inflammatory reactions, or secondary to early brain injury, acute pathophysiological events that occur in the brain within the first 72 hours of aneurysmal SAH. The pathology underlying DCI may involve large artery vasospasm and/or microcirculatory disturbances by microvasospasm, microthrombosis, dysfunction of venous outflow and compression of microvasculature by vasogenic or cytotoxic tissue edema. Recent clinical evidence has shown that large artery vasospasm is not the only cause of DCI, and that both large artery vasospasm-dependent and -independent cerebral infarction causes poor outcome. Animal studies suggest that mechanisms of vasospasm may differ between large artery and arterioles or capillaries, and that many kinds of cells in the vascular wall and brain parenchyma may be involved in the pathogenesis of microcirculatory disturbances. The impairment of the paravascular and glymphatic systems also may play important roles in the development of DCI. As pathological mediators for DCI, glutamate and several matricellular proteins have been investigated in addition to inflammatory molecules. Glutamate is involved in excitotoxicity contributing to cortical spreading ischemia and epileptic activity-related events. Microvascular dysfunction is an attractive mechanism to explain the cause of poor outcomes independently of large cerebral artery vasospasm, but needs more studies to clarify the pathophysiologies or mechanisms and to develop a novel therapeutic strategy.
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    Intussusceptive angiogenesis facilitated by microthrombosis has an important example in angiolipoma. An ultrastructural and immunohistochemical study
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2023) Díaz Flores, Lucio; Gutiérrez, Ricardo; Pino García, Maria; González Gómez, Miriam; Díaz Flores Jr, Lucio; Carrasco, Jose Luis; Álvarez Argüelles, Hugo; Madrid Cuevas, Juan Francisco
    The microvasculature of angiolipoma frequently presents thrombi. Our objectives are to assess whether intussusceptive angiogenesis (IA) participates in vasculature formation in non-infiltrating angiolipoma and, if so, to explore how thrombi are involved in the IA process. For this purpose, we studied angiolipoma specimens (n: 52), using immunohistochemistry, and confocal and electron microscopy. The results showed the presence of folds and pillars, hallmarks of IA, dividing the vessel lumen. Folds showed a cover formed by reoriented endothelial cells from the vessel wall, or from newly formed folds, and a core initially formed by thrombus fragments (clot components as transitional core), which was replaced by extracellular matrix and invaginating pericytes establishing numerous peg-andsocket junctions with endothelial cells (mature core). A condensed plasmatic electron-dense material surrounded and connected folds and pillars with each other and with the vascular wall, which suggests a clot role in fold/pillar arrangement. In conclusion, we contribute to IA participation in capillary network formation in angiolipoma and the immunohistochemical and ultrastructural events by which microthrombosis facilitates IA. Therefore, in addition to the histogenesis of angiolipoma, we provide an easily obtainable substrate for future studies on clot component action in IA, of clinical and therapeutic interest
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    Organ specificity of the structural organization and fine distribution of lymphatic capillary networks: Histochemical study
    (Murcia : F. Hernández, 2000) Kato, S.
    Histochemical studies of the microcirculatory system were reviewed with regard to the organ specificity of the structural organization and fine distribution of the lymphatic capillary network. The lymphatics and blood vessels are characterized by an enzyme-histochemical method using 5'-nucleotidase (5'- Nase), alkaline phosphatase (ALPase) andlor diaminopeptidase (DAPase) staining in additon to an immunohistochemical method. The 5'-Nase-positive lymphatic vessels can be distinguished histochemically from arterial and venous vessels based on ALPase and DAPase activity, respectively. The specificity and localization of the enzyme reactions were confirmed by comparative histochemical studies of the same specimen with light microscopy and scanning or transmission electron microscopy. These histochemical methods are discussed in relation to their ability to demonstrate the organ specificity of vascular networks under normal and pathological conditions.
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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.