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Vascular Remodeling (vascular + remodeling)
Kinds of Vascular Remodeling Selected AbstractsRoles of Endothelial Cell Migration and Apoptosis in Vascular Remodeling during Development of the Central Nervous SystemMICROCIRCULATION, Issue 5 2000SUZANNE HUGHES ABSTRACT Objective: To examine the roles of apoptosis, macrophages, and endothelial cell migration in vascular remodeling during development of the central nervous system. Methods: The terminal deoxynucleotide transferase-mediated dUTP nick end labeling (TUNEL) technique was combined with Griffonia simplicifolia isolectin B4 histochemistry to detect apoptotic endothelial cells in retinal whole-mount preparations derived from rats at various stages of postnatal development as well as from rat pups exposed to hyperoxia. Macrophages were detected by immunohistochemistry with the monoclonal antibody ED1, and proliferating endothelial cells were identified by incorporation of bromodeoxyuridine. Results: Only small numbers of TUNEL-positive endothelial cells were detected during normal development of the retinal vasculature, with the apoptotic cell density in the inner plexus peaking during the first postnatal week and decreasing markedly during the second week, at a time when vessel retraction was widespread. Neither apoptotic endothelial cells nor macrophages were apparent at sites of initiation of vessel retraction. TUNEL-positive endothelial cells were observed in vessels destined to remain. Hyperoxia induced excessive vessel withdrawal, resulting in the generation of isolated vascular segments containing apoptotic endothelial cells. A topographical analysis showed low numbers of proliferating endothelial cells at sites of angiogenesis whereas vascular proliferation was increased in the adjacent inner plexus. Conclusions: Endothelial cell apoptosis and macrophages do not initiate vessel retraction, but rather contribute to the removal of redundant cells throughout the vasculature. We suggest that vessel retraction is mediated by endothelial cell migration and that endothelial cells derived from retracting vascular segments are redeployed in the formation of new vessels. Only when retraction results in compromised circulation and redeployment is not possible, does endothelial cell apoptosis occur. [source] The Extracellular Signal-Regulated Kinase Is Involved in the Effects of Sildenafil on Pulmonary Vascular RemodelingCARDIOVASCULAR THERAPEUTICS, Issue 1 2010Zhen Zeng Pulmonary hypertension is a group of diseases comprising vascular constriction and obstructive changes of the pulmonary vasculature. Phosphodiesterase type 5 inhibitors, for example, sildenafil, can alleviate vascular remodeling in the monocrotaline pulmonary hypertension model in rats. We investigate the mechanisms of sildenafil on the pulmonary vascular remodeling of pulmonary hypertension induced by monocrotaline (MCT) in rats. Thirty Sprague-Dawley rats (weighing 200,220 g) were administered with MCT abdominal cavity injection or equivalent volume of normal saline (NS) (which were treated as C group n = 10) to induce pulmonary hypertension model. Fourteen days later, 20 MCT treated rats were randomly fed with sildenafil (25mg/kg/day) or placebo as S, P group (10 rats for each group), respectively. Another 6 weeks later, mean pulmonary artery pressure (mPAP), index of right ventricular hypertrophy (RV/LV+S) of all animals were measured under general anesthesia. Pulmonary tissue was collected to investigate pathological features of pulmonary arteries and to measure protein expression of ERK1/ERK2 and MKP1. After 6 weeks, there were significant elevated mPAP and RV/LV+S in both P and S groups. The ratio of wall thickness to vessel diameter in pulmonary arteries with diameters <200 ,m were increased in both P and S groups. But the ratio of wall thickness to vessel diameter was smaller in S group than that in P group. The phosphorylation level of ERK1/ERK2 were elevated in both P and S groups, but the level of phosphorlation ERK1/ERK2 were lower in S group than that in P group. Intriguingly, the expression level of MKP1 was significantly increased in both S and P groups, while it was higher in S group than that in P group. The Sildenafil can decrease mPAP and inhibit the progress of pulmonary vascular remodeling in pulmonary hypertension rats. The ERK-MAP kinase signaling pathway might play a role during this process. [source] Man1, an inner nuclear membrane protein, regulates left,right axis formation by controlling nodal signaling in a node-independent mannerDEVELOPMENTAL DYNAMICS, Issue 12 2008Akihiko Ishimura Abstract Man1, an inner nuclear membrane protein, regulates transforming growth factor , signaling by interacting with receptor-associated Smads. In Man1 -deficient (Man1,/,) embryos, vascular remodeling is perturbed by misregulation of Smad activity. Here, we show that Man1,/, embryos exhibit abnormal heart morphogenesis including the looping abnormality. We searched for the molecular basis underlying the heart abnormalities and found that the left side-specific genes responsible for left,right (LR) asymmetry, Nodal, Lefty2, and Pitx2, were expressed bilaterally in the lateral plate mesoderm and that their expression was enhanced significantly in mutants. Notably, Lefty1, a marker for the midline barrier, was maintained in Man1,/, mutants. Crossing Man1,/+ with Nodal hypomorphs (Nodalneo/+), in which Nodal signaling in the node is disrupted, to generate double homozygous embryos (Man1,/,; Nodalneo/neo) revealed that the bilateral Nodal was retained in Man1,/,; Nodalneo/neo embryos. These results suggest that Man1 regulates LR asymmetry by controlling Nodal signaling in a node-independent manner. Developmental Dynamics 237:3565,3576, 2008. © 2008 Wiley-Liss, Inc. [source] Structural and biophysical simulation of angiogenesis and vascular remodeling ,DEVELOPMENTAL DYNAMICS, Issue 4 2001Ralf Gödde Abstract The purpose of this report is to introduce a new computer model for the simulation of microvascular growth and remodeling into arteries and veins that imitates angiogenesis and blood flow in real vascular plexuses. A C++ computer program was developed based on geometric and biophysical initial and boundary conditions. Geometry was defined on a two-dimensional isometric grid by using defined sources and drains and elementary bifurcations that were able to proliferate or to regress under the influence of random and deterministic processes. Biophysics was defined by pressure, flow, and velocity distributions in the network by using the nodal-admittance-matrix-method, and accounting for hemodynamic peculiarities like Fahraeus-Lindqvist effect and exchange with extravascular tissue. The proposed model is the first to simulate interdigitation between the terminal branches of arterial and venous trees. This was achieved by inclusion of vessel regression and anastomosis in the capillary plexus and by remodeling in dependence from hemodynamics. The choice of regulatory properties influences the resulting vascular patterns. The model predicts interdigitating arteriovenous patterning if shear stress-dependent but not pressure-dependent remodeling was applied. By approximating the variability of natural vascular patterns, we hope to better understand homogeneity of transport, spatial distribution of hemodynamic properties and biomass allocation to the vascular wall or blood during development, or during evolution of circulatory systems. © 2001 Wiley-Liss, Inc. [source] Molecular characterization of the vascular features of focal nodular hyperplasia and hepatocellular adenoma: A role for angiopoietin-1,HEPATOLOGY, Issue 2 2010Annette S. H. Gouw Focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA) are two hepatic nodular lesions of different etiologies. FNH, a polyclonal lesion, is assumed to be a regenerative reaction following a vascular injury, whereas HCA is a monoclonal, benign neoplastic lesion. In addition to features that are predominantly found in either FNH or HCA (e.g., dystrophic vessels in FNH and single arteries in HCA), FNH and HCA share morphological vascular abnormalities such as dilated sinusoids. We hypothesized that these anomalous vascular features are associated with altered expression of growth factors involved in vascular remodeling. This was based on reports of morphologically abnormal hepatic vasculature and nodular lesions in transgenic models of hepatocytic overexpression of angiopoietin-1 (Ang-1), a member of the angiopoietin family, which is crucially involved in vascular morphogenesis and homeostasis. We investigated gene and protein expression of members of the angiopoietin system and vascular endothelial growth factor A (VEGF-A) and its receptors in 9 FNH samples, 13 HCA samples, and 9 histologically normal livers. In comparison with normal samples, a significant increase in Ang-1 was found in FNH (P < 0.01) and HCA (P < 0.05), whereas no significant changes in Ang-2, receptor tyrosine kinase with immunoglobulin-like and EGF-like domains 2, VEGF-A, or vascular endothelial growth factor receptor 2 (VEGFR-2) were observed. Conclusion: Because of the different etiological contexts of a preceding vascular injury in FNH and a neoplastic growth in HCA, Ang-1 might exert different effects on the vasculature in these lesions. In FNH, it could predominantly stimulate recruitment of myofibroblasts and result in dystrophic vessels, whereas in HCA, it may drive vascular remodeling that produces enlarged vessels and arterial sprouting that generates single arteries. Hepatology 2010 [source] The angiogenic makeup of human hepatocellular carcinoma does not favor vascular endothelial growth factor/angiopoietin-driven sprouting neovascularization,,HEPATOLOGY, Issue 5 2008Wenjiao Zeng Quantitative data on the expression of multiple factors that control angiogenesis in hepatocellular carcinoma (HCC) are limited. A better understanding of the mechanisms underlying angiogenesis in HCC will improve the rational choice of anti-angiogenic treatment. We quantified gene and protein expression of members of the vascular endothelial growth factor (VEGF) and angiopoietin systems and studied localization of VEGF, its receptors VEGFR-1 and VEGFR-2, Angiopoietin (Ang)-1 and Ang-2, and their receptor, in HCC in noncirrhotic and cirrhotic livers. We employed real-time reverse transcription polymerase chain reaction (RT-PCR), western blot, and immunohistology, and compared the outcome with highly angiogenic human renal cell carcinoma (RCC). HCC in noncirrhotic and cirrhotic livers expressed VEGF and its receptors to a similar extent as normal liver, although in cirrhotic background, VEGFR-2 levels in both tumor and adjacent tissue were decreased. Ang-1 expression was slightly increased compared with normal liver, whereas Tie-2 was strongly down-regulated in the tumor vasculature. Ang-2 messenger RNA (mRNA) levels were also low in HCCs of both noncirrhotic and cirrhotic livers, implying that VEGF-driven angiogenic sprouting accompanied by angiopoietin-driven vascular destabilization is not pronounced. In RCC, VEGF-A levels were one order of magnitude higher. At the same time, endothelially expressed Ang-2 was over 30-fold increased compared with expression in normal kidney, whereas Ang-1 expression was decreased. Conclusion: In hepatocellular carcinoma, tumor vascularization is not per se VEGF/angiopoietin driven. However, increased CD31 expression and morphological changes representative of sinusoidal capillarization in tumor vasculature indicate that vascular remodeling is taking place. This portends that therapeutic intervention of HCC at the level of the vasculature is optional, and that further studies into the molecular control thereof are warranted. (HEPATOLOGY 2008.) [source] Beneficial effect of enalapril in spontaneously hypertensive rats cardiac remodeling with nitric oxide synthesis blockadeJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 4 2002R. L. de Andrade Zorzi Abstract Aims. To study the efficiency of an angiotensin converting enzyme inhibitor on the blood pressure (BP) and the myocardium remodeling when spontaneously hypertensive rats (SHRs) are submitted to nitric oxide synthesis (NOs) blockade (with L-NAME) and simultaneously treated. Methods. Young adult male SHRs were separated in four groups (n = 5) and treated for 20 days: Control, L-NAME, L-NAME+Enalapril, and Enalapril. The alterations of the BP, heart mass/body mass ratio and stereological parameters for myocytes, connective tissue and intramyocardial vessels were studied among the groups. Results. The SHRs with NOs blockade showed a great modification of the myocardium with extensive areas of reparative and interstitial fibrosis and accentuated hypertrophy of the cardiac myocytes (cross sectional area 60% higher in animals taking L-NAME than in Control SHRs). Comparing the SHRs with NO deficiency (L-NAME group), the Control SHRs and the Enalapril treated SHRs significant differences were found in the BP and in all stereological parameters. The NO deficiency caused an important BP increment in SHRs that was partially attenuated by Enalapril. This Enalapril effect was more pronounced in Control SHRs. A significant increment of the intramyocardial vessels was observed in NO deficient SHRs and Control SHRs treated with Enalapril demonstrated by the stereology (greater microvascular densities in treated SHRs). Conclusion. Enalapril administration showed a beneficial effect on vascular remodeling and myocardial hypertrophy in SHRs. In SHRs with NO blockade, however, the beneficial effect of Enalapril occurred only in vascular remodeling. [source] Mechanotransduction in endothelial cell migrationJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2005Song Li Abstract The migration of endothelial cells (ECs) plays an important role in vascular remodeling and regeneration. EC migration can be regulated by different mechanisms such as chemotaxis, haptotaxis, and mechanotaxis. This review will focus on fluid shear stress-induced mechanotransduction during EC migration. EC migration and mechanotransduction can be modulated by cytoskeleton, cell surface receptors such as integrins and proteoglycans, the chemical and physical properties of extracellular matrix (ECM) and cell,cell adhesions. The shear stress applied on the luminal surface of ECs can be sensed by cell membrane and associated receptor and transmitted throughout the cell to cell,ECM adhesions and cell,cell adhesions. As a result, shear stress induces directional migration of ECs by promoting lamellipodial protrusion and the formation of focal adhesions (FAs) at the front in the flow direction and the disassembly of FAs at the rear. Persistent EC migration in the flow direction can be driven by polarized activation of signaling molecules and the positive feedback loops constituted by Rho GTPases, cytoskeleton, and FAs at the leading edge. Furthermore, shear stress-induced EC migration can overcome the haptotaxis of ECs. Given the hemodynamic environment of the vascular system, mechanotransduction during EC migration has a significant impact on vascular development, angiogenesis, and vascular wound healing. J. Cell. Biochem. © 2005 Wiley-Liss, Inc. [source] Thrombogenic and atherogenic activities of lysophosphatidic acidJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2004Wolfgang Siess Abstract Lysophosphatidic acid (LPA) has been identified as a biologically active lipid in mildly-oxidized LDL, human atherosclerotic lesions, and the supernatant of activated platelets. The evidence that LPA has thrombogenic and atherogenic activities has increased substantially in recent years. Supporting the thrombogenic activity of LPA, analysis of the core region of human carotid plaques revealed recently the presence of alkyl- and acyl-molecular species from LPA with high platelet-activating potency (16:0 alkyl-LPA, 20:4 acyl-LPA). LPA, lipid extracts of atherosclerotic plaques, and the lipid-rich core elicited shape change and, in synergy with other platelet stimuli, aggregation of isolated platelets. This effect was completely abrogated by prior incubation of platelets with LPA receptor antagonists. Furthermore, LPA at concentrations approaching those found in vivo, induced platelet shape change, aggregation, and platelet-monocyte aggregate formation in blood. LPA-stimulated platelet aggregation was mediated by the ADP-stimulated activation of the P2Y1 and P2Y12 receptors. Supporting its atherogenic activity, LPA is a mitogen and motogen to vascular smooth muscle cells (VSMCs) and an activator of endothelial cells and macrophages. Recently, LPA has been identified as an agonist of the peroxisome proliferator activating receptor , (PPAR,), which is a key regulator of atherogenesis. LPA elicits progressive neointima formation, which is fully abolished by GW9662, an antagonist of PPAR,. We propose that LPA plays a central role in eliciting vascular remodeling and atherogenesis. Furthermore, upon rupture of lipid-rich atherosclerotic plaques, LPA may trigger platelet aggregation and intra-arterial thrombus formation. Antagonists of LPA receptors might be useful in preventing LPA-elicited thrombus formation and neointima formation in patients with cardiovascular diseases. © 2004 Wiley-Liss, Inc. [source] Oxidized low density lipoprotein decreases Rankl-induced differentiation of osteoclasts by inhibition of Rankl signaling,JOURNAL OF CELLULAR PHYSIOLOGY, Issue 3 2009Cécile Mazičre The role of OxLDL in the generation and progression of atherosclerosis is well admitted. In addition, it is well known that atherosclerosis is often accompanied by perturbations in bone remodeling, resulting in osteoporosis. In the current studies, the effect of Cu2+ -oxidized LDL (OxLDL) on RANKL-induced RAW264.7 mouse monocytes-macrophages differentiation to osteoclasts and on RANKL signaling pathway was investigated. OxLDL, within the range of 10,50,µg protein/ml, prevented RANKL-induced generation of multinucleated osteoclast-like cells and RANKL-induced tartrate resistant acid phosphatase (TRAP) activity. OxLDL also prevented the RANKL-induced phosphorylation of ERK, p38 and JNK kinases, together with the RANKL-induced DNA binding activities of NFkappaB and NFAT transcription factors. Concomitantly, OxLDL enhanced RANKL-induced generation of reactive oxygen species in a dose-dependent manner. The antioxidant glutathione (GSH) prevented whereas the prooxidant compound buthionine-sulfoximine (BSO) enhanced the effect of OxLDL on RANKL-induced oxidative stress and RANKL-induced differentiation. Finally, OxLDL also prevented RANKL-induced TRAP activity and RANKL-induced bone resorbing activity of human peripheral blood mononuclear cells. These results demonstrate that OxLDL, by generation of an intracellular oxidative stress, prevents the differentiation of osteoclasts by inhibition of RANKL signaling pathway. This might be related to the fact that atherosclerosis is accompanied by perturbations in bone and vascular remodeling, leading to osteoporosis and vascular calcification. J. Cell. Physiol. 221: 572,578, 2009. © 2009 Wiley-Liss, Inc. [source] The core-aldehyde 9-oxononanoyl cholesterol increases the level of transforming growth factor ,1-specific receptors on promonocytic U937 cell membranesAGING CELL, Issue 2 2009Simona Gargiulo Summary Among the broad variety of compounds generated via oxidative reactions in low-density lipoproteins (LDL) and subsequently found in the atherosclerotic plaque are aldehydes that are still esterified to the parent lipid, termed core aldehydes. The most represented cholesterol core aldehyde in LDL is 9-oxononanoyl cholesterol (9-ONC), an oxidation product of cholesteryl linoleate. 9-ONC, at a concentration detectable in biological material, markedly up-regulates mRNA expression and protein level of both the pro-fibrogenic and pro-apoptotic cytokine transforming growth factor ,1 (TGF-,1) and the TGF-, receptor type I (T,RI) in human U937 promonocytic cells. We also observed increased membrane presentation of TGF-, receptor type II (T,RII). Experiments employing the T,RI inhibitor SB431542, or the TGF, antagonist DANFc chimera, have shown that the effect on T,RI is directly induced by 9-ONC, while T,RII up-regulation seems stimulated by its specific ligand, i.e. TGF,1, over-secreted meanwhile by treated cells. Increased levels of the cytokine and of its specific receptors in 9-ONC-treated cells clearly occurs through stimulation of extracellular signal-regulated kinase 1 and 2 (ERK1/2), as demonstrated by ERK1/2 knockdown experiments using mitogen-activated protein kinase/extracellular signal-regulated kinase 1 and 2 (MEK1 and MEK2) siRNAs, or PD98059, a selective MEK1/2 inhibitor. 9-ONC might thus sustain further vascular remodeling due to atherosclerosis, not simply by stimulating synthesis of the pro-fibrogenic cytokine TGF-,1 in vascular cells, but also and chiefly by enhancing the TGF-,1 autocrine loop, because of the marked up-regulation of the cytokine's specific receptors T,RI and T,RII. [source] Initial feasibility of a multi-station high resolution three-dimensional dark blood angiography protocol for the assessment of peripheral arterial diseaseJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 4 2009Georgeta Mihai PhD Abstract Purpose To evaluate the feasibility of a multi-station three dimensional (3D) T1-weighted turbo spin echo (TSE) dark-blood Sampling Perfection with Application optimized Contrasts using different flip angle Evolution sequence (T1w-SPACE), to assess aorta, iliac, and superficial femoral (SFA) arteries (inflow vessels) by comparing it with a multi-station contrast enhanced MR angiography (CE-MRA) with identical resolution. Materials and Methods A total of 6 volunteers and 14 peripheral arterial disease (PAD) patients were included in the study. Abdominal and thigh T1w-SPACE and lower leg time-resolved MRA (TR-MRA) with low dose contrast were followed by 3-station CE-MRA. Quantitative measurements of lumen area at 17 locations from T1w-SPACE and CE-MRA were obtained. Additionally, vessel wall areas at the same locations were obtained from the T1w-SPACE images. Results Quantitative comparison of lumen areas with T1w-SPACE and CE-MRA revealed strong correlation between the two techniques and strong inter-observer agreement for each of the two imaging methods (r > 0.9; P < 0.001). Localized vessel wall area measurements obtained in PAD patients were significantly greater compared with those obtained in normal volunteers (mean difference 43.75 ± 12.46 mm2; P < 0.001). Stenosis severity obtained from T1w-SPACE localized measurements showed significant arterial area stenosis in PAD patients. Conclusion T1w-SPACE imaging of inflow vessels is feasible, and in addition to CE-MRA has the ability to assess atherosclerotic plaque and vascular remodeling. J. Magn. Reson. Imaging 2009;30:785,793. © 2009 Wiley-Liss, Inc. [source] Pulmonary hypertension is ameliorated in mice deficient in thrombin-activatable fibrinolysis inhibitorJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 4 2010L. QIN Summary.,Background: The fibrinolytic system has been implicated in the pathogenesis of pulmonary hypertension (PH). Thrombin-activatable fibrinolysis inhibitor (TAFI) inhibits fibrinolysis and therefore its absence would be expected to increase fibrinolysis and ameliorate PH. Objective: The objective of the present study was to evaluate the effect of TAFI deficiency on pulmonary hypertension in the mouse. Methods and results: PH was induced in C57/Bl6 wild-type (WT) or TAFI-deficient (KO) mice by weekly subcutaneous treatment with 600 mg kg,1 monocrotaline (MCT) for 8 weeks. PH was inferred from right heart hypertrophy measured using the ratio of right ventricle-to-left ventricle-plus-septum weight [RV/(LV+S)]. Pulmonary vascular remodeling was analyzed by morphometry. TAFI-deficient MCT-treated and wild-type MCT-treated mice suffered similar weight loss. TAFI-deficient MCT-treated mice had reduced levels of total protein and tumor necrosis factor-alpha (TNF-,), interleukin-6 (IL-6), transforming growth factor-, (TGF-,) and monocyte chemoattractant protein-1 (MCP-1) in bronchial alveolar lavage compared with wild-type MCT-treated mice. The ratio of RV to (LV+S) weight was significantly higher in WT/MCT than in KO/MCT mice. The pulmonary artery wall area and vascular stenosis were both greater in MCT-treated WT mice compared with MCT-treated TAFI-deficient mice. Conclusions: TAFI-deficient MCT-treated mice had less pulmonary hypertension, vascular remodeling and reduced levels of cytokines compared with MCT-treated WT animals, possibly as a result of reduced coagulation activation. [source] Angiogenesis and lymphangiogenesis in bronchial asthmaALLERGY, Issue 8 2010A. Detoraki To cite this article: Detoraki A, Granata F, Staibano S, Rossi FW, Marone G, Genovese A. Angiogenesis and lymphangiogenesis in bronchial asthma. Allergy 2010; 65: 946,958. Abstract Neovascularization plays a prominent role in inflammation and tissue remodeling in several chronic inflammatory disorders. Vessel number and size, vascular surface area and vascular leakage are all increased in biopsies from patients with asthma. High levels of VEGF and other angiogenic factors have been detected in tissues and biological samples of patients with asthma and correlate with disease activity and inversely with airway hyper-responsiveness. Inflammation in the lung stimulates the growth of new blood vessels and these contribute to the airway obstruction or airway hyper-responsiveness, or both. Effector cells of inflammation (human lung mast cells, basophils, eosinophils, macrophages, etc.) are major sources of a vast array of angiogenic and lymphangiogenic factors. Inhaled corticosteroids reduce vascularity and growth factor expression and might modulate bronchial vascular remodeling in asthma. Specific antagonists to VEGF and other angiogenic factors and their receptors might help to control chronic airway inflammation and vascular remodeling and offer a novel approach for the treatment of chronic inflammatory lung disorders. [source] The Role of K+ Channels in Determining Pulmonary Vascular Tone, Oxygen Sensing, Cell Proliferation, and Apoptosis: Implications in Hypoxic Pulmonary Vasoconstriction and Pulmonary Arterial HypertensionMICROCIRCULATION, Issue 8 2006ROHIT MOUDGIL ABSTRACT Potassium channels are tetrameric, membrane-spanning proteins that selectively conduct K+ at near diffusion-limited rates. Their remarkable ionic selectivity results from a highly-conserved K+ recognition sequence in the pore. The classical function of K+ channels is regulation of membrane potential (EM) and thence vascular tone. In pulmonary artery smooth muscle cells (PASMC), tonic K+ egress, driven by a 145/5 mM intracellular/extracellular concentration gradient, contributes to a EM of about ,60 mV. It has been recently discovered that K+ channels also participate in vascular remodeling by regulating cell proliferation and apoptosis. PASMC express voltage-gated (Kv), inward rectifier (Kir), calcium-sensitive (KCa), and two-pore (K2P) channels. Certain K+ channels are subject to rapid redox regulation by reactive oxygen species (ROS) derived from the PASMC's oxygen-sensor (mitochondria and/or NADPH oxidase). Acute hypoxic inhibition of ROS production inhibits Kv1.5, which depolarizes EM, opens voltage-sensitive, L-type calcium channels, elevates cytosolic calcium, and initiates hypoxic pulmonary vasoconstriction (HPV). Hypoxia-inhibited K+ currents are not seen in systemic arterial SMCs. Kv expression is also transcriptionally regulated by HIF-1, and NFAT. Loss of PASMC Kv1.5 and Kv2.1 contributes to the pathogenesis of pulmonary arterial hypertension (PAH) by causing a sustained depolarization, which increases intracellular calcium and K+, thereby stimulating cell proliferation and inhibiting apoptosis, respectively. Restoring Kv expression (via Kv1.5 gene therapy, dichloroacetate, or anti-survivin therapy) reduces experimental PAH. Electrophysiological diversity exists within the pulmonary circulation. Resistance PASMC have a homogeneous Kv current (including an oxygen-sensitive component), whereas conduit PASMC current is a Kv/KCa mosaic. This reflects regional differences in expression of channel isoforms, heterotetramers, splice variants, and regulatory subunits as well as mitochondrial diversity. In conclusion, K+ channels regulate pulmonary vascular tone and remodeling and constitute potential therapeutic targets in the regression of PAH. [source] Roles of Endothelial Cell Migration and Apoptosis in Vascular Remodeling during Development of the Central Nervous SystemMICROCIRCULATION, Issue 5 2000SUZANNE HUGHES ABSTRACT Objective: To examine the roles of apoptosis, macrophages, and endothelial cell migration in vascular remodeling during development of the central nervous system. Methods: The terminal deoxynucleotide transferase-mediated dUTP nick end labeling (TUNEL) technique was combined with Griffonia simplicifolia isolectin B4 histochemistry to detect apoptotic endothelial cells in retinal whole-mount preparations derived from rats at various stages of postnatal development as well as from rat pups exposed to hyperoxia. Macrophages were detected by immunohistochemistry with the monoclonal antibody ED1, and proliferating endothelial cells were identified by incorporation of bromodeoxyuridine. Results: Only small numbers of TUNEL-positive endothelial cells were detected during normal development of the retinal vasculature, with the apoptotic cell density in the inner plexus peaking during the first postnatal week and decreasing markedly during the second week, at a time when vessel retraction was widespread. Neither apoptotic endothelial cells nor macrophages were apparent at sites of initiation of vessel retraction. TUNEL-positive endothelial cells were observed in vessels destined to remain. Hyperoxia induced excessive vessel withdrawal, resulting in the generation of isolated vascular segments containing apoptotic endothelial cells. A topographical analysis showed low numbers of proliferating endothelial cells at sites of angiogenesis whereas vascular proliferation was increased in the adjacent inner plexus. Conclusions: Endothelial cell apoptosis and macrophages do not initiate vessel retraction, but rather contribute to the removal of redundant cells throughout the vasculature. We suggest that vessel retraction is mediated by endothelial cell migration and that endothelial cells derived from retracting vascular segments are redeployed in the formation of new vessels. Only when retraction results in compromised circulation and redeployment is not possible, does endothelial cell apoptosis occur. [source] Study of intussusceptive angiogenesis in inflammatory regional lymph nodes by scanning electron microscopyMICROSCOPY RESEARCH AND TECHNIQUE, Issue 1 2010Tíssiana Rachel Rossi-Schneider Abstract The aim of the present study was to verify the occurrence of intussusceptive angiogenesis in blood vessels from submandibular lymph nodes responsible for lymphatic drainage of the tongue. A surgical wound inflicted on the ventral tongue of male Wistar rats and submandibular regional lymph nodes were evaluated at different postoperative periods. Scanning electron microscopy (SEM) was used to observe 123 lymph nodes at times 2, 3, 7, 10, 14, and 21 postoperative days. During the analysis of the vascular models with SEM, intussusceptive angiogenesis was observed in all groups evaluated. This was more extensive on the second and third postoperative days (83.33% and 80%, respectively), representing in these groups the expansion of the vascular chain of lymph nodes. At 21 postoperative days, intussusceptive angiogenesis (42.85%) was suggestive of vascular remodeling. Microsc. Res. Tech. 2009. © 2009 Wiley-Liss, Inc. [source] REVIEW ARTICLE: The Contribution of Macrophages to Normal and Pathological PregnanciesAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 6 2010Takeshi Nagamatsu Citation Nagamatsu T, Schust DJ. The contribution of macrophages to normal and pathological pregnancies. Am J Reprod Immunol 2010 Macrophages represent one of the major leukocyte subsets in the uterine decidua. Owing to their remarkable phenotypic plasticity, decidual macrophages can participate in diverse activities during pregnancy. At baseline, decidual macrophages are characterized by an immunosuppressive phenotype and M2 polarization, supporting feto-maternal immune tolerance. In early pregnancy, macrophage-derived pro-angiogenic factors prompt vascular remodeling within the uterine wall to ensure appropriate utero-placental circulation. Upon invasion by pathogens, pattern recognition receptors on decidual macrophages help to alter the characteristics of these malleable cells toward an M1, inflammatory phenotype. Similar inflammatory characteristics are seen in those macrophages that accumulate in the lower segment of the uterus to drive cervical ripening. Disturbances in the tight control that balances macrophage function during pregnancy can trigger the development of pregnancy complications. Here, we discuss the physiologic role of uterine macrophages at different stages of pregnancy and describe their relevance in selected pregnancy disorders. [source] REVIEW ARTICLE: Human NK Cells in Pregnant Uterus: Why There?AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 5 2008Philippe Le Bouteiller Human Natural Killer (NK) cells are present in great number in pregnant uterine mucosa. They must be there for specialized functions, but which ones? This review discusses important recent observations that further contribute to this fascinating debate. Firstly, an array of corroborating findings indicates that uterine NK cell proliferation is synchronized with the cyclic surge of progesterone. Secondly, uterine NK cells are unlikely to exert a direct control on the embryo implantation. Thirdly, these NK cells influence the uterine vascular remodeling in early pregnancy but might not be the single key element that control trophoblast invasion. Finally, uterine NK cells are likely to be an important component of the local maternal immune response to pathogen infections. [source] Donor and Recipient Origin of Mesenchymal and Endothelial Cells in Chronic Renal Allograft RemodelingAMERICAN JOURNAL OF TRANSPLANTATION, Issue 3 2009H. Rienstra Chronic transplant dysfunction (CTD) is the leading cause for limited kidney graft survival. Renal CTD is characterized by interstitial and vascular remodeling leading to interstitial fibrosis, tubular atrophy and transplant vasculopathy (TV). The origin of cells and pathogenesis of interstitial and vascular remodeling are still unknown. To study graft-versus-recipient origin of interstitial myofibroblasts, vascular smooth muscle cells (SMCs) and endothelial cells (ECs), we here describe a new rat model for renal CTD using Dark Agouti kidney donors and R26 human placental alkaline phosphatase transgenic Fischer344 recipients. This model showed the development of CTD within 12 weeks after transplantation. In interstitial remodeling, both graft- and recipient-derived cells contributed to a similar extent to the accumulation of myofibroblasts. In arteries with TV, we observed graft origin of neointimal SMCs and ECs, whereas in peritubular and glomerular capillaries, we detected recipient EC chimerism. These data indicate that, within the interstitial and vascular compartments of the transplanted kidney, myofibroblasts, SMCs and ECs involved in chronic remodeling are derived from different sources and suggest distinct pathogenetic mechanisms within the renal compartments. [source] Calcium antagonists, diltiazem and nifedipine, protect broilers against low temperature-induced pulmonary hypertension and pulmonary vascular remodelingANIMAL SCIENCE JOURNAL, Issue 4 2010Ying YANG ABSTRACT This study was designed to determine whether calcium antagonists, diltiazem and nifedipine, can depress low temperature-induced pulmonary hypertension (PH) in broilers (also known as ascites) and to characterize their efficacy on hemodynamics and pulmonary artery function. Chicks were randomly allocated into six experimental groups and orally administered with vehicle, 5.0 mg/kg body weight (BW)/12 h nifedipine or 15.0 mg/kg BW/12 h diltiazem from 16 to 43 days of age under low temperature. The mean pulmonary arterial pressure (mPAP), the ascites heart index (AHI), the erythrocyte packed cell volume (PCV) and the relative percentage of medial pulmonary artery thickness were examined on days 29, 36 and 43. The data showed that administration of diltiazem protected broilers from low temperature-induced pulmonary hypertension and vascular remodeling. Although nifedipine prevented mPAP from increasing during the early stage, it did not suppress the development of PH during the late stage and did not keep heart rate (HR), PCV, AHI and the thickness of pulmonary small artery smooth muscle layer at the normal levels. Taken together, our results showed that diltiazem can effectively prevent low temperature-induced pulmonary hypertension in broilers with fewer side-effects and may be a potential compound for the prevention of this disease in poultry industry. [source] Soluble endoglin modulates aberrant cerebral vascular remodeling,ANNALS OF NEUROLOGY, Issue 1 2009Yongmei Chen MD Objective Brain arteriovenous malformations (AVMs) are an important cause of neurological morbidity in young adults. The pathophysiology of these lesions is poorly understood. A soluble form of endoglin (sEng) has been shown to cause endothelial dysfunction and induce preeclampsia. We tested if sEng would be elevated in brain AVM tissues relative to epilepsy brain tissues, and also investigated whether sEng overexpression via gene transfer in the mouse brain would induce vascular dysplasia and associated changes in downstream signaling pathways. Methods Expression levels of sEng in surgical specimens were determined by Western blot assay and enzyme-linked immunosorbent assay. Vascular dysplasia, levels of matrix metalloproteinase (MMP), and oxidative stress were determined by immunohistochemistry and gelatin zymography. Results Brain AVMs (n = 33) had higher mean sEng levels (245 ± 175 vs 100 ± 60, % of control, p = 0.04) compared with controls (n = 8), as determined by Western blot. In contrast, membrane-bound Eng was not significantly different (108 ± 79 vs 100 ± 63, % of control, p = 0.95). sEng gene transduction in the mouse brain induced abnormal vascular structures. It also increased MMP activity by 490 ± 30% (MMP-9) and 220 ± 30% (MMP-2), and oxidants by 260 ± 20% (4-hydroxy-2-nonenal) at 2 weeks after injection, suggesting that MMPs and oxidative radicals may mediate sEng-induced pathological vascular remodeling. Interpretation The results suggest that elevated sEng may play a role in the generation of sporadic brain AVMs. Our findings may provide new targets for therapeutic intervention for patients with brain AVMs. Ann Neurol 2009;66:19,27 [source] Angiogenesis: now and then,APMIS, Issue 7-8 2004CARLA COSTA Angiogenesis or new blood vessel formation plays an essential role during embryogenesis, adult vascular remodeling and in several pathological disorders, as in tumor development. Although sprouting of blood vessels is the principal angiogenic mechanism, additional ones, such as the recruitment of bone marrow-derived cells, have recently been described. These processes are controlled by several molecules, although members of the VEGF family of angiogenic factors and its receptors seem to be the main mediators. Initially, VEGF receptors were described as endothelial specific; however, further studies have reported their presence in several types of cells of non-endothelial origin, such as tumor cells. This VEGF receptor altered expression has suggested an angiogenesis-independent growth advantage mechanism on certain types of cancers by the generation of autocrine loops. A possible role in tumorigenesis and a potential novel target in cancer therapy have been hypothesized. Detection of other receptors and molecules considered to be angiogenic players has also been observed on tumor cells. Currently, their clinical significance as well as their potential as therapeutic targets for the treatment of certain cancers is being evaluated, having in mind the future development of promising mechanism-based therapies. The aspects mentioned above are the main focus of this review, which aims to throw light on recent findings respecting angiogenesis and novel therapeutic approaches. [source] Clinical Images: Iloprost-induced vascular remodelingARTHRITIS & RHEUMATISM, Issue 7 2007Athina Pyrpasopoulou MD No abstract is available for this article. [source] Chemical-induced, nonlethal, developmental model of dissecting aortic aneurysm,BIRTH DEFECTS RESEARCH, Issue 1 2006Bin Gong BACKGROUND A chemical-induced, nonlethal, dissecting aortic aneurysm (DAA) is described following in utero exposure to semicarbazide, an inhibitor of the vascular enzyme semicarbazide sensitive amine oxidase (SSAO). METHODS Sprague-Dawley rat dams were given semicarbazide (0.096,49.000 mg/kg/day) by IP injection on gestation days (GDs) 14,20, a period of rapid aortic development. Newborn rats (day 1) were killed and their thoracic organs were removed en bloc for near-serial cross sections and routine histopathology, Movat stain for elastin, and immunohistochemistry to differentiate cells involved in the evolution of the DAA. In subsequent experiments, pups from treated dams (0.096,6.125 mg/kg/day) were allowed to survive for 7 or 28 days. RESULTS DAA occurred in nearly 100% of the rats at all doses except the lowest tested (1.530, 0.096 mg/kg/day). Dissections frequently extended to the carotids and, less frequently, to the abdominal aorta. Remodeling of vascular lesions proceeded by organization of collections of blood in vascular media (the "false lumen"), proliferation of vascular smooth muscle cells, fibrosis, and formation of irregular frayed elastic lamellae in healed vascular media. Biochemical quantitation and Western blot analysis of main extracellular matrix proteins on GD 20 showed no overt difference in expression of collagen type I, fibrillin-1, or elastin. CONCLUSION This developmental model provides investigators an opportunity to explore the pathologic mechanisms of DAA and to examine the potential long-term effects of vascular remodeling of DAA. Birth Defects Research (Part A), 2005. © 2005 Wiley-Liss, Inc. [source] The Extracellular Signal-Regulated Kinase Is Involved in the Effects of Sildenafil on Pulmonary Vascular RemodelingCARDIOVASCULAR THERAPEUTICS, Issue 1 2010Zhen Zeng Pulmonary hypertension is a group of diseases comprising vascular constriction and obstructive changes of the pulmonary vasculature. Phosphodiesterase type 5 inhibitors, for example, sildenafil, can alleviate vascular remodeling in the monocrotaline pulmonary hypertension model in rats. We investigate the mechanisms of sildenafil on the pulmonary vascular remodeling of pulmonary hypertension induced by monocrotaline (MCT) in rats. Thirty Sprague-Dawley rats (weighing 200,220 g) were administered with MCT abdominal cavity injection or equivalent volume of normal saline (NS) (which were treated as C group n = 10) to induce pulmonary hypertension model. Fourteen days later, 20 MCT treated rats were randomly fed with sildenafil (25mg/kg/day) or placebo as S, P group (10 rats for each group), respectively. Another 6 weeks later, mean pulmonary artery pressure (mPAP), index of right ventricular hypertrophy (RV/LV+S) of all animals were measured under general anesthesia. Pulmonary tissue was collected to investigate pathological features of pulmonary arteries and to measure protein expression of ERK1/ERK2 and MKP1. After 6 weeks, there were significant elevated mPAP and RV/LV+S in both P and S groups. The ratio of wall thickness to vessel diameter in pulmonary arteries with diameters <200 ,m were increased in both P and S groups. But the ratio of wall thickness to vessel diameter was smaller in S group than that in P group. The phosphorylation level of ERK1/ERK2 were elevated in both P and S groups, but the level of phosphorlation ERK1/ERK2 were lower in S group than that in P group. Intriguingly, the expression level of MKP1 was significantly increased in both S and P groups, while it was higher in S group than that in P group. The Sildenafil can decrease mPAP and inhibit the progress of pulmonary vascular remodeling in pulmonary hypertension rats. The ERK-MAP kinase signaling pathway might play a role during this process. [source] Pharmacological and Clinical Studies with Temocapril, an Angiotensin Converting Enzyme Inhibitor that is Excreted in the BileCARDIOVASCULAR THERAPEUTICS, Issue 3 2004Kenichi Yasunari ABSTRACT Temocapril is an angiotensin converting enzyme inhibitor (ACEI), a prodrug with a thiazepine ring. Its active form, temocaprilat, is slightly more potent than enalaprilat in inhibiting ACE isolated from rabbit lung. The inhibitory potency of temocaprilat on isolated rat aorta is 3 times that of enalaprilat. Temocapril is excreted in the bile and urine and can be used in patients with renal insufficiency. It reduces blood pressure without causing any significant change in heart rate or cardiac output. Temocapril has been reported to improve endothelial dysfunction in vitro by suppressing increased oxidative stress. In vivo it improves reactive hyperemia in patients with essential hypertension. It has been reported to prevent coronary vascular remodeling in vivo by suppressing local ACE and increased oxidative stress. In humans temocapril has been found to improve insulin resistance partly by increasing adiponectin levels. Cardiac remodeling was improved by temocapril not only in experiment animals but also in humans. It improves renal function and decreases urinary albumin excretion in diabetics as well as in hypertensive patients. Temocapril is currently marketed only in Japan. Considering its beneficial effects and unique pharmaco-kinetics, temocapril, is likely to be introduced in other countries as well. [source] | |||||||||||||||||||||||||