scholarly journals Hirudin, heparin, and placebo during deep arterial injury in the pig. The in vivo role of thrombin in platelet-mediated thrombosis.

Circulation ◽  
1990 ◽  
Vol 82 (4) ◽  
pp. 1476-1484 ◽  
Author(s):  
M Heras ◽  
J H Chesebro ◽  
M W Webster ◽  
J S Mruk ◽  
D E Grill ◽  
...  
Keyword(s):  
Arterial Injury

Heparan sulfate side chains have a critical role in the inhibitory effects of perlecan on vascular smooth muscle cell response to arterial injury

2014 ◽  
Vol 307 (3) ◽  
pp. H337-H345 ◽  
Author(s):  
Lara Gotha ◽  
Sang Yup Lim ◽  
Azriel B. Osherov ◽  
Rafael Wolff ◽  
Beiping Qiang ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Critical Role ◽  
Arterial Injury ◽  
Side Chains ◽  
Wild Type ◽  
Injury Response ◽  
Migratory Response

Perlecan is a proteoglycan composed of a 470-kDa core protein linked to three heparan sulfate (HS) glycosaminoglycan chains. The intact proteoglycan inhibits the smooth muscle cell (SMC) response to vascular injury. Hspg2Δ3/Δ3 (MΔ3/Δ3) mice produce a mutant perlecan lacking the HS side chains. The objective of this study was to determine differences between these two types of perlecan in modifying SMC activities to the arterial injury response, in order to define the specific role of the HS side chains. In vitro proliferative and migratory activities were compared in SMC isolated from MΔ3/Δ3 and wild-type mice. Proliferation of MΔ3/Δ3 SMC was 1.5× greater than in wild type ( P < 0.001), increased by addition of growth factors, and showed a 42% greater migratory response than wild-type cells to PDGF-BB ( P < 0.001). In MΔ3/Δ3 SMC adhesion to fibronectin, and collagen types I and IV was significantly greater than wild type. Addition of DRL-12582, an inducer of perlecan expression, decreased proliferation and migratory response to PDGF-BB stimulation in wild-type SMC compared with MΔ3/Δ3. In an in vivo carotid artery wire injury model, the medial thickness, medial area/lumen ratio, and macrophage infiltration were significantly increased in the MΔ3/Δ3 mice, indicating a prominent role of the HS side chain in limiting vascular injury response. Mutant perlecan that lacks HS side chains had a marked reduction in the inhibition of in vitro SMC function and the in vivo arterial response to injury, indicating the critical role of HS side chains in perlecan function in the vessel wall.

Absence of transforming growth factor beta 1 in murine platelets reduces neointima formation without affecting arterial thrombosis

2017 ◽  
Vol 117 (09) ◽  
pp. 1782-1797 ◽  
Author(s):  
Eva Schütz ◽  
Magdalena L. Bochenek ◽  
Dennis R. Riehl ◽  
Markus Bosmann ◽  
Thomas Münzel ◽  
...  
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Arterial Injury ◽  
Neointima Formation ◽  
Proliferating Cells ◽  
The Media

SummaryPlatelet degranulation at the site of vascular injury prevents bleeding and may affect the chronic vascular wound healing response. Transforming Growth Factor (TGF)-β1 is a major component of platelet α-granules known to accumulating in thrombi. It was our aim to determine the role of TGFβ1 released from activated platelets for neointima formation following arterial injury and thrombosis. Mice with platelet-specific deletion of TGFβ1 (Plt.TGFβ-KO) underwent carotid artery injury. Immunoassays confirmed the absence of active TGFβ1 in platelet releasates and plasma of Plt.TGFβ-KO mice. Whole blood analyses revealed similar haematological parameters, and tail cut assays excluded major bleeding defects. Platelet aggregation and the acute thrombotic response to injury in vivo did not differ between Plt.TGFβ-KO and Plt.TGFβ-WT mice. Morphometric analysis revealed that absence of TGFβ1 in platelets resulted in a significant reduction of neointima formation with lower neointima area, intima-to-media ratio, and lumen stenosis. On the other hand, the media area was enlarged in mice lacking TGFβ1 in platelets and contained increased amounts of proteases involved in latent TGFβ activation, including MMP2, MMP9 and thrombin. Significantly increased numbers of proliferating cells and cells expressing the mesenchymal markers platelet-derived growth factor receptor-β or fibroblast-specific protein-1, and the macrophage antigen F4/80, were observed in the media of Plt.TGFβ-KO mice, whereas the medial smooth muscle-actin-immuno-positive area and collagen content did not differ between genotypes. Our findings support an essential role for platelet-derived TGFβ1 for the vascular remodelling response to arterial injury, apparently independent from the role of platelets in thrombosis or haemostasis.Supplementary Material to this article is available online at www.thrombosis-online.com.

scholarly journals Roles of vascular endothelial and smooth muscle cells in the vasculoprotective effect of insulin in a mouse model of restenosis

2021 ◽  
Vol 18 (3) ◽  
pp. 147916412110273
Author(s):  
Yusaku Mori ◽  
Marel Gonzalez Medina ◽  
Zhiwei Liu ◽  
June Guo ◽  
Luke S Dingwell ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Insulin Treatment ◽  
Muscle Cells ◽  
Arterial Injury ◽  
Vascular Endothelial ◽  
Muscle Myosin

Background: Insulin exerts vasculoprotective effects on endothelial cells (ECs) and growth-promoting effects on vascular smooth muscle cells (SMCs) in vitro, and suppresses neointimal growth in vivo. Here we determined the role of ECs and SMCs in the effect of insulin on neointimal growth. Methods: Mice with transgene CreERT2 under the control of EC-specific Tie2 (Tie2-Cre) or SMC-specific smooth muscle myosin heavy chain promoter/enhancer (SMMHC-Cre) or littermate controls were crossbred with mice carrying a loxP-flanked insulin receptor (IR) gene. After CreERT2-loxP-mediated recombination was induced by tamoxifen injection, mice received insulin pellet or sham (control) implantation, and underwent femoral artery wire injury. Femoral arteries were collected for morphological analysis 28 days after wire injury. Results: Tamoxifen-treated Tie2-Cre+ mice showed lower IR expression in ECs, but not in SMCs, than Tie2-Cre− mice. Insulin treatment reduced neointimal area after arterial injury in Tie2-Cre− mice, but had no effect in Tie2-Cre+ mice. Tamoxifen-treated SMMHC-Cre+ mice showed lower IR expression in SMCs, but not in ECs, than SMMHC-Cre− mice. Insulin treatment reduced neointimal area in SMMHC-Cre− mice, whereas unexpectedly, it failed to inhibit neointima formation in SMMHC-Cre+ mice. Conclusion: Insulin action in both ECs and SMCs is required for the “anti-restenotic” effect of insulin in vivo.

scholarly journals A Crucial Role of Glycoprotein VI for Platelet Recruitment to the Injured Arterial Wall In Vivo

2002 ◽  
Vol 197 (1) ◽  
pp. 41-49 ◽  
Author(s):  
Steffen Massberg ◽  
Meinrad Gawaz ◽  
Sabine Grüner ◽  
Valerie Schulte ◽  
Ildiko Konrad ◽  
...  
Keyword(s):  
Vascular Injury ◽  
Vessel Wall ◽  
Thrombus Formation ◽  
Arterial Occlusion ◽  
Arterial Injury ◽  
Platelet Glycoprotein ◽  
Glycoprotein Vi ◽  
Strict Requirement

Platelet adhesion and aggregation at sites of vascular injury is crucial for hemostasis but may lead to arterial occlusion in the setting of atherosclerosis and precipitate diseases such as myocardial infarction. A current hypothesis suggests that platelet glycoprotein (GP) Ib interaction with von Willebrand factor recruits flowing platelets to the injured vessel wall, where subendothelial fibrillar collagens support their firm adhesion and activation. However, so far this hypothesis has not been tested in vivo. Here, we demonstrate by intravital fluorescence microscopy of the mouse carotid artery that inhibition or absence of the major platelet collagen receptor, GPVI, abolishes platelet–vessel wall interactions after endothelial denudation. Unexpectedly, inhibition of GPVI by the monoclonal antibody JAQ1 reduced platelet tethering to the subendothelium by ∼89%. In addition, stable arrest and aggregation of platelets was virtually abolished under these conditions. Using different models of arterial injury, the strict requirement for GPVI in these processes was confirmed in GPVI-deficient mice, where platelets also failed to adhere and aggregate on the damaged vessel wall. These findings reveal an unexpected role of GPVI in the initiation of platelet attachment at sites of vascular injury and unequivocally identify platelet–collagen interactions (via GPVI) as the major determinant of arterial thrombus formation.

Multiple integrin-ligand interactions synergize in shear-resistant platelet adhesion at sites of arterial injury in vivo

Blood ◽  
2003 ◽  
Vol 102 (12) ◽  
pp. 4021-4027 ◽  
Author(s):  
Sabine Grüner ◽  
Miroslava Prostredna ◽  
Valerie Schulte ◽  
Thomas Krieg ◽  
Beate Eckes ◽  
...  
Keyword(s):  
Vessel Wall ◽  
Platelet Adhesion ◽  
Arterial Injury ◽  
Β1 Integrins ◽  
Ligand Interactions ◽  
Integrin Ligand ◽  
Aggregation Of Platelets ◽  
Αiibβ3 Integrin

Abstract Damage to the integrity of the vessel wall results in exposure of the subendothelial extracellular matrix (ECM), which triggers integrin-dependent adhesion and aggregation of platelets. The role of platelet β1 integrins in these processes remains mostly undefined. Here, we demonstrate by intravital fluorescence microscopy that platelet adhesion and thrombus growth on the exposed ECM of the injured carotid artery is not significantly altered in α2-null mice and even in mice with a Cre/loxP-mediated loss of all β1 integrins on their platelets. In contrast, inhibition of αIIbβ3 integrin on platelets in wild-type mice blocked aggregate formation and reduced platelet adhesion by 60.0%. Strikingly, αIIbβ3 inhibition had a comparable effect in α2-null mice, demonstrating that other receptors mediate shear-resistant adhesion in the absence of functional α2β1 and αIIbβ3. These were identified to be α5β1 and/or α6β1 as αIIbβ3 inhibition abrogated platelet adhesion in β1-null mice. We conclude that shear-resistant platelet adhesion on the injured vessel wall in vivo is a highly integrated process involving multiple integrin-ligand interactions, none of which by itself is essential. (Blood. 2003;102:4021-4027)

Tissue Factor as a Therapeutic Target

2001 ◽  
Vol 85 (03) ◽  
pp. 375-376 ◽  
Author(s):  
Ronald Bach ◽  
Nigel Key
Keyword(s):  
Animal Models ◽  
Tissue Factor ◽  
Limited Proteolysis ◽  
Metastatic Potential ◽  
Arterial Injury ◽  
Factor Vii ◽  
Tumor Cell Lines ◽  
Coagulation Mechanism

SummaryTissue factor (TF) is a member of the cytokine receptor superfamily that functions as the essential receptor and co-factor for factor VII/ VIIa. Assembly of the TF-VII(a) complex on cellular surfaces initiates blood coagulation by limited proteolysis of zymogen factors IX and X, ultimately leading to the generation of thrombin. The realization that the TF pathway is the primary (if not the sole) mechanism for activation of coagulation in vivo has sparked an explosion in research in the last decade that has documented the central role of TF in certain forms of pathological thrombosis. Although these are too numerous to list, several are especially noteworthy by virtue of strongly supportive data in animal models. These include disseminated intravascular coagulation (DIC) induced by sepsis, and arterial thrombosis overlying an atherosclerotic plaque - the usual final event in myocardial infarction and unstable angina. In the case of arterial injury, inhibition of TF in animal models has also suggested that this pathway is important in mediating intimal hyperplasia. Other recent seminal observations include the recognition of several possible roles for TF that may not depend upon activation of the coagulation mechanism. For example, TF expression by certain tumor cell lines may determine enhanced metastatic potential, and in some tumors TF may promote angiogenesis (1).

Reduced Plasma Fibronectin Leads to Delayed Thrombus Growth in the Injured Arterioles in Vivo.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2619-2619 ◽  
Author(s):  
Jana Matuskova ◽  
Beatrice Cambien ◽  
Crystal Piffath ◽  
Denisa D. Wagner
Keyword(s):  
Thrombus Formation ◽  
Arterial Injury ◽  
Conditional Knockout ◽  
Arterial System ◽  
Plasma Fibronectin ◽  
Wild Type ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract In addition to von Willebrand factor and fibrinogen, plasma fibronectin (pFN) contributes significantly to thrombus development in arteries. Complete deficiency of plasma fibronectin (in pFN conditional knockout mice) affects thrombus formation and growth and subsequent occlusion of injured arterioles in vivo. We wanted to study a more physiological decrease of plasma fibronectin without having to induce interferon production in the mice to excise the FN gene. Reduced pFN levels are common in patients with liver disease, sepsis and following trauma or surgery. To evaluate the effect of a reduced amount of plasma fibronectin on thrombus formation at arterial shear rate, we used the ferric chloride model of arterial injury in fibronectin heterozygote mice which have 50% of the normal plasma level of FN. Two groups of mice were observed by intravital microscopy - FN heterozygote (FN+/−) and corresponding age matched wild-type controls (FN +/+). The reduced level of pFN did not affect the early platelet interaction with subendothelium but caused a delay of several minutes in appearance of the first thrombus in the injured arteriole (15 min in FN +/− vs 6 min in FN+/+, p<0.001). Although the thrombi were stably anchored to the vessel wall, the growth of the thrombus was slowed down because of the constant platelet shedding in fibronectin heterozygote mice. Consequently, this lack of firm adhesion of the platelets led to occlusion delay (36 min in FN +/− vs 28 min in FN+/+, p<0.01) with the majority of arterioles in the FN+/− mice not occluding by 40 minutes after injury. In conlusion, the phenotype of thrombosis in the mice with 50% of normal pFN level strikingly resembles the phenotype observed in mice with induced complete deficiency of pFN. This further emphasizes the fundamental role of this plasma protein in thrombosis in vivo in the arterial system.

Mitochondrial matrix calcium ions regulate energy production in myocardium: A cytochemical study

1990 ◽  
Vol 48 (2) ◽  
pp. 166-167
Author(s):  
W.A. Jacob ◽  
R. Hertsens ◽  
A. Van Bogaert ◽  
M. De Smet
Keyword(s):  
Energy Metabolism ◽  
Calcium Ions ◽  
Energy Production ◽  
Regulation Of Respiration ◽  
Free Calcium ◽  
Mitochondrial Matrix ◽  
Cytochemical Study ◽  
Nmr Techniques

In the past most studies of the control of energy metabolism focus on the role of the phosphorylation potential ATP/ADP.Pi on the regulation of respiration. Studies using NMR techniques have demonstrated that the concentrations of these compounds for oxidation phosphorylation do not change appreciably throughout the cardiac cycle and during increases in cardiac work. Hence regulation of energy production by calcium ions, present in the mitochondrial matrix, has been the object of a number of recent studies.Three exclusively intramitochondnal dehydrogenases are key enzymes for the regulation of oxidative metabolism. They are activated by calcium ions in the low micromolar range. Since, however, earlier estimates of the intramitochondnal calcium, based on equilibrium thermodynamic considerations, were in the millimolar range, a physiological correlation was not evident. The introduction of calcium-sensitive probes fura-2 and indo-1 made monitoring of free calcium during changing energy metabolism possible. These studies were performed on isolated mitochondria and extrapolation to the in vivo situation is more or less speculative.

Meiotic CENP-C is a shepherd: bridging the space between the centromere and the kinetochore in time and space

2020 ◽  
Vol 64 (2) ◽  
pp. 251-261
Author(s):  
Jessica E. Fellmeth ◽  
Kim S. McKim
Keyword(s):  
Chromosome Segregation ◽  
New Technologies ◽  
Early Prophase ◽  
Unique Role ◽  
Kinetochore Assembly ◽  
M Phase ◽  
In Vivo Analysis ◽  
Meiosis I

Abstract While many of the proteins involved in the mitotic centromere and kinetochore are conserved in meiosis, they often gain a novel function due to the unique needs of homolog segregation during meiosis I (MI). CENP-C is a critical component of the centromere for kinetochore assembly in mitosis. Recent work, however, has highlighted the unique features of meiotic CENP-C. Centromere establishment and stability require CENP-C loading at the centromere for CENP-A function. Pre-meiotic loading of proteins necessary for homolog recombination as well as cohesion also rely on CENP-C, as do the main scaffolding components of the kinetochore. Much of this work relies on new technologies that enable in vivo analysis of meiosis like never before. Here, we strive to highlight the unique role of this highly conserved centromere protein that loads on to centromeres prior to M-phase onset, but continues to perform critical functions through chromosome segregation. CENP-C is not merely a structural link between the centromere and the kinetochore, but also a functional one joining the processes of early prophase homolog synapsis to late metaphase kinetochore assembly and signaling.

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