Browsing by Subject "Intussusceptive angiogenesis"

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    Intussusceptive angiogenesis and its counterpart intussusceptive lymphangiogenesis
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2020) Díaz Flores, L.; Gutiérrez, R.; Gayoso, S.; García, M.P.; González-Gómez, M.; Díaz-Flores Jr, L.; Sánchez, R.; Carrasco, J.L.; Madrid, J.F.
    Intussusceptive angiogenesis (IA) is currently considered an important alternative and complementary form of sprouting angiogenesis (SA). Conversely, intussusceptive lymphangiogenesis (IL) is in an initial phase of study. We compare their morphofunctional characteristics, since many can be shared by both processes. To that end, the following aspects are considered: A) The concept of IA and IL as the mechanism by which blood and lymphatic vessels split, expand and remodel through transluminal pillar formations (hallmarks of intussusception). B) Terminology and historical background, with particular reference to the group of Burri, including Djonov and Patan, who initiated and developed the vessel intussusceptive concept in blood vessels. C) Incidence in normal (e.g. in the sinuses of developing lymph nodes) and pathologic conditions, above all in vessel diseases, such as dilated veins in hemorrhoidal disease, intravascular papillary endothelial hyperplasia (IPEH), sinusoidal hemangioma, lobular capillary hemangioma, lymphangiomas/lymphatic malformations and vascular transformation of lymph nodes. D) Differences and complementarity between vessel sprouting and intussusception. E) Characteristics of the cover (endothelial cells) and core (connective tissue components) of pillars and requirements for pillar identification. F) Structures involved in pillar formation, including endothelial contacts of opposite vessel walls, interendothelial bridges, merged adjacent capillaries, vessel loops and spilt pillars. G) Structures resulting from pillars with intussusceptive microvascular growth, arborization, remodeling and segmentation (compartmentalization). H) Influence of intussusception in the morphogenesis of vessel tumors/ pseudotumors; and I) Hemodynamic and molecular control of vessel intussusception, including VEGF, PDGF BB, Hypoxia, Notch, Endoglobin and Nitric oxide.
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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; Madrid, Juan Francisco; Álvarez Argüelles, Hugo
    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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    Myriad pillars formed by intussusceptive angiogenesis as the basis of intravascular papillary endothelial hyperplasia (IPEH). IPEH is intussusceptive angiogenesis made a lesion
    (Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2021) Díaz-Flores, Lucio; Gutiérrez, Ricardo; González-Gómez, Miriam; Pino García, Mª; Carrasco, José Luis; Díaz-Flores, Lucio; Madrid, Juan F.
    . Intussusceptive angiogenesis (IA) is the process by which pre-existing blood vessels split, expand and remodel through intravascular pillar formation. In previous works, we studied the morphologic characteristics of intravascular papillary endothelial hyperplasia (IPEH) and suggested the participation of IA in the histogenesis of the lesion. Our current goal is to demonstrate that myriad papillae in IPEH are in fact myriad pillars, the hallmarks of IA. For this purpose, specimens of 14 cases of IPEH were used for conventional histologic techniques, immunohistochemistry and immunofluorescence in confocal microscopy. The studies showed the following pillar characteristics: a) structural composition by an endothelial cell (EC) cover and a connective core, b) characteristic pillar image and its appearance and disappearance in whole-mounted and series of individual views in confocal microscopy (requirements for pillar identification), c) arrangement in masses, alignments and meshes, and d) formation from vein intimal ECs, which extend and originate loops that encircle vein wall components (interstitial tissue structures: ITSs) and fibrin. The encircling ECs form the pillar cover and the encircled ITSs or fibrin form the initial core. Intraluminal endothelial bridges also originate from the vessel wall and from the pillars (nascent and thin pillars). In conclusion, the formation of myriad pillars, predominantly in veins, is the basis of IPEH. This lesion may therefore be considered an excessive expression of IA: IA becomes a lesion.
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    Venous vasculature drives neovascularization and stroma formation in pancreatic neuroendocrine tumors via intussusceptive angiogenesis and vein intravasation
    (Universidad de Murcia, Departamento de Histología e Histopatología, 2025) Díaz-Flores Lucio; Gutiérrez Ricardo; Pino García Maria; González-Gómez Miriam; Carrasco Jose Luis; Madrid Juan Francisco; Díaz-Flores Varela Lucio; Biología Celular e Histología
    The microenvironment of pancreatic neuroendocrine tumors (PanNETs) has been extensively studied; however, research on their venous vasculature has largely focused on tumor invasion and metastasis. This study aims to (a) evaluate the role of veins/venules in PanNET neovascularization, tumor intravasation, and stromal tract (trabecula) formation, including the potential involvement of intussusceptive angiogenesis (IA); and (b) compare the trabeculae observed in PanNETs with those found in hepatic cavernous hemangiomas (HCHs) where IA in veins plays an important role. To achieve these objectives, we conducted an integrated morphological approach encompassing primary PanNETs (n=42), hepatic metastases of PanNETs (n=4), and HCHs (n=11). Our findings in both primary and metastatic PanNETs reveal (a) the involvement of veins/venules in tumor neovascularization, with IA acting synergistically with sprouting angiogenesis, through the formation of pillars, meshes, and complex meshes (vessels that encapsulate tumor clusters-endothelium-coated tumor clusters); (b) the development of connective tissue around the neo-vasculature, potentially involving adventitial CD34-positive stromal cells/telocytes; and (c) a notable architectural resemblance between the trabeculae of PanNETs and those of HCHs. In conclusion, this work highlights the pivotal role of the preexisting venous vasculature in PanNET neovascularization, tumor intravasation, and stroma formation, with active participation of IA. These findings provide a pathophysiological foundation for future in-depth molecular investigations and may pave the way for new studies on therapeutic strategies targeting angiogenic mechanisms