DigitalUM :: Browsing by Subject "Endothelium"

Browsing by Subject "Endothelium"

Now showing 1 - 12 of 12

Open Access
Angiogenesis: an update
(Murcia : F. Hernández, 1994) Díaz-Flores, Lucio; Gutiérrez, Ricardo; Varela, H.
Angiogenesis is the neovascularization or formation of new blood vessels from the established microcirculation. It is particularly important and indispensable in a large number of normal and pathological processes during pre- and post-natal life, including neoplasia, inflammation, wound repair and collaterization in response to ischemic stimuli. The current interest in the role of neovascularization in the transition from hyperplasia to neoplasia, as well as in the tumour growth and metastasis, has brought about a large number of studies on angiogenesis. The complex processes of neovascularization, quiescent in the adult organism, may occur rapidly in several circumstances, with the implication of the following events: a) endothelial cell (EC) and pericyte activation; b) basal lamina degradation; c) migration and proliferation of EC and pericytes; d) formation of a new capillary vessel lumen; e) appearance of pericytes around the new capillaries; f) development of a new basal lamina; g) capillary loop formation; h) persistence or involution, and differentiation of the new vessels; and i) capillary network formation and, eventually, organization into larger microvessels. The use of numerous "in vivo" and "in vitro" systems has facilitated the assessment of angiogenesis control, in which angiogenic (fibroblast growth factors, vascular endothelial growth factor, platelet endothelial growth factor, E series prostaglandin, angiogenin, monobutyrin) and antiangiogenic (cartilagederived angiogenic inhibitor, thrombospondin, protamine, platelet factor-4, interferon, angiostatic antibiotics, steroids) substances intervene. Heparin and heparin sulphate also play a key role in these mechanisms. A greater knowledge of angiogenesis control may lead to the development of a potential therapy in angiogenesis-related processes.
Open Access
Autocrine endothelial regulation in brain stem vessels of newborn piglets
(Murcia : F. Hernández, 1999) Lange, D.; Funa, K.; Ishisaki, K.; Bauer, R.; Wollina, Uwe
Vasoactive intestinal peptide (VIP) is known as a potent regulator for the development of the central nervous system (CNS). The neonatal period of brain development is characterised by rapid cellular proliferation in parallel with neuronal differentiation and angiogenesis. We examined the expression of native VIP and the VIP receptor-associated protein by immunohistochemistry as well as the expression of VIP mRNA by in situ hybridisation in the brain stem of newborn piglets. We found both the mRNA and the protein of VIP as well as the VIP receptor-associated protein in endothelial cells of veins, arteries and capillaries in the marginal zone of brain stem tissue sections, especially in pons and mesencephalon, as well as in pia1 vessels. The coexpression of native VIP, VIP mRNA and the VIP receptor-associated protein within the endothelium suggests the presence of an autocrine loop, which has been detected so far only in neuroblastoma cells. This expression pattern gives evidence to the immaturity of endothelial cells at birth and the presence of an adaptive response in the VIP-regulated system during the change from intra- to extrauterine life.
Open Access
Dimensions of compartments and membrane surfaces in the intact rabbit heart of importance in studies on intramyocardial transfer of blood-borne substances
(Universidad de Murcia. Departamento de Biología Celular e Histología, 2016) van der Vusse, Ger J.; Verheyen, Fons; Reneman, Robert S.; Arts, Theo
Cardiac studies on the uptake, storage and intramyocardial transfer of blood-borne substances require detailed information on the geometric ultrastructural dimensions of myocardial compartments and parts thereof, and the membranes separating these compartments. Such a specific ultrastructural set of data of the heart is yet lacking. In the present study, we quantitatively assessed these dimensions in glutaraldehyde-perfusion fixed rabbit hearts by means of histological and tailored mathematical techniques. We showed the true ellipsoid nature of the myocardial capillary cross section and estimated the mean capillary diameter dcap. After correction for the ellipsoid shape, dcap was found to be 5.21±1.41 μm. Effective widths of the endothelial cell and the pericapillary interstitium (is1), dimensions of importance in diffusion, amounted to 187±7 and 160±10 nm, respectively. The fractional volume of the large vessels (arteries and veins larger than 10 µm), capillaries, endothelium, is1, cardiomyocytes, non-pericapillary interstitium is2, t-tubular compartment and interstitial cells amounted on average to 5.92%, 9.36%, 1.83%, 1.94%, 73.07%, 5.97%, 0.95% and 0.96%, respectively, of total myocardial volume, defined as the cardiac tissue volume, the large blood vessels included. Normalized to total myocardial volume, the surface area of the luminal and abluminal endothelial membranes and of the cardiomyocyte membrane opposing the endothelial cells amounted to 75.2±5.5x103, 82.2±6.0x103 and 89.1±6.5x103 m2/m3, respectively. The present study provides quantitative information about ultrastructural dimensions of the adult rabbit heart, among others, of importance for studies on cardiac uptake, and intramyocardial transfer and storage of blood-supplied substances.
Open Access
Experimental study of WGA binding on the endothelial cell surface in cerebral ischemia
(Murcia : F. Hernández, 1986) Shozo Nishida; Fumiharu Akai; Shingo Hiruma; Mitsuyo Maeda; Kurenai Tanji; Shigeo Hashimoto
The relationship between the saccharide chain on the endothelial cell surface and the permeability of intracerebral blood vessels has been studied. In the present study, wheat germ agglutinin (WGA) was perfused into capillaries in the area postrema of the normal Mongolian gerbil, where the blood brain barrier (BBB) is known to lack, and into intracerebral blood vessels, the BBB of which had been destroyed by experimentally induced brain ischemia. The light microscopic features of the sections from WGA-perfused brain tissues of the normal gerbil revealed that most of the blood vessels, including capillaries in the brain parenchyma, showed positive findings (the reaction induced a very distinct staining of the vascular wall) from which the course and structure of the fine vessels could be determined. The reaction to WGA on the diaphragma fenestra (DF) in capillaries in the area postrema was relatively weak, and DF without the reaction were occasionally revealed by electron microscopy. The gerbil, in which cerebral ischemia had been induced, also showed partial defect of the reaction with WGA on the lumina1 side of the endothelial cells. The results of the present experiment suggest some degree of correlation between the saccharide chains, including the specific monosaccharide of WGA, on the endothelial cell surface and permeability. It was considered that lectin can be used as an index for morphological observations, suggesting an alteration in function of the endothelial cell membrane. In addition, the perfusion method in this experiment suggested the possibility of distinguishing pinocytotic vesicles from pits of cell membranes.
Open Access
Expression of CD34 and CD146 vascular markers contributes to the immunological function of the human palatine tonsil
(Universidad de Murcia. Departamento de Biología Celular e Histología, 2018) Jovic, Marko; Avramović, Verica; Vlahović, Predrag; Velickov, Aleksandra; Petrović, Vladimir
The fundamental function of the palatine tonsil is the immune response to airborne and foodborne pathogenic agents. Small blood vessels have an important role in the provision of a special microenvironment in which the immune response occurs. In this study, we investigated the expression of vascular markers CD34 and CD146 and basal lamina marker - type IV collagen - in the small blood vessels of the human palatine tonsil in the context of their role in the immunological function of the tonsil. The tonsils were collected after tonsillectomy from ten patients with chronic tonsillitis, aged 18-28 years. Five-µm-thick paraffin sections were routinely stained with haematoxylin and eosin, while the studied markers (CD34, CD146 and type IV collagen) were detected immunohistochemically using LSAB2/HRP method. CD34 was expressed equally in the capillaries within and below the crypt epithelium, in lymphoid follicles and in high endothelial venules localized para- and interfollicularly. CD146 molecule was expressed on the luminal surface of endothelial cells in the capillaries of the crypt epithelium, while its expression in high endothelial venules was seen on the luminal and lateral surfaces of the cuboidal endothelial cells. In contrast to the basal lamina of intraepithelial capillaries, where collagen IV-immunopositivity is mostly seen as a continuing line, the basal lamina of high endothelial venules was seen as a two- or three-layered structure beneath the cuboidal endothelial cells. The specifics of expression of CD34, CD146, and type IV collagen confirm the morphofunctional specialization of endothelium in crypt epithelium capillaries, and also in endothelium of high endothelial venules, which is directly associated with the role of these vessels in the immune function of the tonsil.
Open Access
Eﬀects of flavonoids in experimental models of arterial hypertension
(Bentham Science Publishers, 2021-08-12) Marín Atucha, Noemí; Romecín, Paola; Vargas, Félix; García-Estañ López, Joaquín; Fisiología; Facultades de la UMU::Facultad de Medicina
Flavonoids are a class of substances of a vegetal origin with many interesting actions from the point of view of human disease. Interest in ﬂavonoids in the diet has increased in recent years due to the publication of basic, clinical and epidemiological studies that have shown a whole array of salutary eﬀects related to intake of ﬂavonols and ﬂavones as well as a lower morbility and mortality of cardiovascular diseases. Since arterial hypertension is the most common modiﬁable risk factor for cardiovascular diseases, this review will focus mainly on the eﬀects of ﬂavonoids on the cardiovascular system with relation to the elevation of blood pressure. Its antihypertensive eﬀects as well as the many investigations performed in experimental models of arterial hypertension, are reviewed in this mini-review.
Open Access
Microtubules regulate aortic endothelial cell actin microfilament reorganization in intact and repairing monolayers
(Murcia : F. Hernández, 2005) Lee, J.S.Y.; Gotlieb, A.I.
To understand the role of microtubules and microfilaments in regulating endothelial monolayer integrity and repair, and since microtubules and microfilaments show some co-alignment in endothelial cells, we tested the hypothesis that microtubules organize microfilament distribution. Disruption of microtubules with colchicine in resting confluent aortic endothelial monolayers resulted in disruption of microfilament distribution with a loss of dense peripheral bands, an increase in actin microfilament bundles, and an associated increase of focal adhesion proteins at the periphery of the cells. However, when microfilaments were disrupted with cytochalasin B, microtubule distribution did not change. During the early stages of wound repair of aortic endothelial monolayers, microtubules and microfilaments undergo a sequential series of changes in distribution prior to cell migration. They are initially distributed randomly relative to the wound edge, then align parallel to the wound edge and then elongate perpendicular to the wound edge. When microtubules in wounded cultures were disrupted, dense peripheral bands and lamellipodia formation were lost with increases in central stress fibers. However, following microfilament disruption, microtubule redistribution was not disrupted and the microtubules elongated perpendicular to the wound edge similar to non-treated cultures. Microtubules may organize independently of microfilaments while microfilaments require microtubules to maintain normal organization in confluent and repairing aortic endothelial monolayers.
Open Access
Perivascular nerves and vascular endothelium: recent advances
(Murcia : F. Hernández, 2002) Loesch, A.
Within the last few years, advances have been made regarding perivascular nerves and the endothelium of the vascular system, both potentially important in the understanding of the mechanisms of local control of blood flow. Endothelin-1 (ET-1) has been identified in rat cerebrovascular nerve s , neuropeptide Y (NPY) has been demonstrated in umbilical endothelium, the arg i n i n e - vasopressin (VP) system has been discovered in the heart (including coronary endothelium), and P2X receptors have been o b s e r ved in vascular endothelial cells. After a brief introduction to vascular biology, this rev i ew will focus on the above-mentioned new data
Open Access
Presence of laminin and 67KDa laminin-receptor on endothelial surface of lung capillaries. An immunocytochemical study
(Murcia : F. Hernández, 1996) Hilario, E.; Unda, F.; Perez-Yarza, G.; Álvarez, A.; Garcia-Sanz, M.; Aliño, S.F.
The existence of cell surface-associated molecules has been claimed to play a major role in cellular recognition and interaction. In this respect, different tumor cell lines express laminin and its receptor, and this expression has been correlated with metastatic potential. In the present work, we have studied, by electron microscopic immunolabeling methods, the presence of laminin and 67KDa lamininreceptor on the surface of endothelial cells of lung blood capillaries. To label these molecules, we have developed an easy method in which the labeling is carried out "in situ", in previously excised lungs. The presence of both molecules was observed on the luminal surface of endothelial capillaries and, in many cases, gold particles were associated to small open vesicles of the endothelial cells. The results suggest that these molecules, traditionally associated to extracellular matrix, are also expressed in cellular surface of the lung vascular bed.
Open Access
The response of subpleural pulmonary capillary endothelium to hydrothorax in rats
(Murcia : F. Hernández, 1987) Shumko, John Z.; DeFouw, David .
The principal focus of this study was to evaluate the hypothesis that increased interstitial fluid pressures served to stimulate de novo vesicle formation in pulmonary capillary endothelium. Direct measurements of interstitial fluid pressures within the alveolar septa pose great technical difficulty. The pleural space and subpleural capillaries are easily accessible, and thus, provide a more feasible model to test this hypothesis. After hydrostatic pressure of pleural space fluid was increased by periodic saline infusions into the pleural cavity, vesicle numerical densities were significantly increased in portions of the subpleural capillary endothelium. Those segments of the endothelium that directly apposed the interstitium of the visceral pleura displayed de novo vesicle formation. The endothelial segments located immediately adjacent to the alveolar epithelium were not affected by the elevated interstitial fluid pressures. In addition to the increased vesiculation, those same segments of the endothelium were characterized by increased attenuation of their cytoplasmic compartments. These conformational changes in the plasmalemma of portions of the subpleural capillary endothelium provide support to the tentative hypothesis, however, whether the increased numbers of vesicles contribute to a potential transendothelial transport system or expand a possible static network of membrane invaginations remains uncertain.
Open Access
Tumor-associated fibroblasts (Part II): functional impact on tumor tissue
(Murcia : F. Hernández, 2002) Kunz-Schughart, L.A.; Knuechel, R.
The article focuses on the functional impact of tumor-associated fibroblasts (TAF) on its surrounding cells. It intends to cover the recent knowledge on TAF, the phenotype, and expression profile of which have been described in the first part of the rev i ew series ( Kunz-Schughart and Knuechel, 2002). The present r ev i ew is subdivided into two main chapters: (1) functional impact of TAF on tumor cells and (2) fibroblast-host cell interactions in tumor tissue. In the first paragraph of chapter (1) about the role of fibroblasts in tumor cell growth and differentiation it is reve a l e d , h ow strongly cellular interaction is dependent on fibroblast and tumor cell type as well as the spatial ratio between the cells. The variation of cellular behav i o r depending on quantity of molecules holds also true for the group of ECM molecules, e.g. the balance between MMPs and TIMPs, which provide an interesting therapeutic target in tumor tissue. This is one of the topics addressed in the second paragraph which focuses on tumor cell dissemination. Chapter (2) addresses the relation of TAF to other intra- or peritumoral host cells. The hypoxia-related angiogenesis induction of fibroblasts via growth factor secretion (e.g. VEGF) is considered as important as the immune modulatory properties of fibroblasts on immune cells, such as m o n o cytes/macrophages. These cellular properties can be tested under controlled conditions in threedimensional heterologous cultures of human cells, p r oviding the chance for systematic modification to assess therapeutic effects in an in vivo like environment.
Open Access
Von Willebrand factor is associated with atrial fibrillation development in ischaemic patients after cardiac surgery
(Oxford University Press, 2016-09) Lahoz, Álvaro; Roldan, Vanessa; Jover, Eva; Romero Aniorte, Ana I.; Jara Rubio, Rubén; Arribas, José María; García Alberola, Arcadio; Cánovas López, Sergio; Valdés, Mariano; Marín, Francisco; Martínez Cáceres, Carlos Manuel; Hernández Romero, Diana; Cirugía, Pediatría y Obstetricia y Ginecología
Aims Atrial fibrillation (AF) is associated with an increased morbidity and mortality after cardiac surgery. Von Willebrand factor (vWF) has been proposed as a biomarker of endothelial damage/dysfunction. We hypothesized that vWF levels could be used as valuable biomarker for AF occurrence after cardiac surgery. Moreover, we explored the potential association between vWF and tissue remodelling as possible implication in post-surgical AF. Methods and results We prospectively recruited 100 consecutive patients who undergoing programmed cardiac surgery with cardiopulmonary bypass and with no previous history of AF. Plasma vWF levels were determined from citrated plasma samples. Right atrial appendage tissue was obtained during cardiac surgery, and vWF expression as well as interstitial fibrosis was analysed by immunostaining and Masson's trichrome, respectively. We found raised vWF plasma levels in ischaemic vs. valvular patients (200.2 ± 66.3 vs. 157.2 ± 84.3 IU/dL; P = 0.015). Fibrosis degree was associated with plasma vWF levels. Plasma vWF was an independent prognostic marker for AF development in ischaemic patients [odds ratio, OR 6.44 (95% confidence interval, CI 1.40–36.57), P = 0.035]. Conclusion Plasma vWF levels are associated with tissue fibrosis in patients undergoing cardiac surgery and with post-surgical AF development in ischaemic patients. These findings suggest an association among vWF levels, atrial remodelling, and AF development. It is supported by higher vWF expression in right atrial tissue in ischaemic patients, who developed post-surgical AF.

Browsing by Subject "Endothelium"

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