scholarly journals Antithrombotic, procoagulant, and fibrinolytic mechanisms in cerebral circulation: implications for brain injury and protection

1997 ◽  
Vol 2 (6) ◽  
pp. E7 ◽  
Author(s):  
Berislav V. Zlokovic
Keyword(s):  
Brain Injury ◽  
Tissue Factor ◽  
Plasminogen Activator ◽  
Protein C ◽  
Molecular Mechanisms ◽  
Biological Significance ◽  
Brain Protection ◽  
Ischemic Insult ◽  
The Brain ◽  
Pai 1

Maintaining a delicate balance among anticoagulant, procoagulant, and fibrinolytic pathways in the cerebral microcirculation is of major importance for normal cerebral blood flow. Under physiological conditions and in the absence of provocative stimuli, the anticoagulant and fibrinolytic pathways prevail over procoagulant mechanisms. Blood clotting is essential to minimize bleeding and to achieve hemostasis; however, excessive clotting contributes to thrombosis and may predispose the brain to infarction and ischemic stroke. Conversely, excessive bleeding due to enhanced anticoagulatory and fibrinolytic mechanisms could predispose the brain to hemorrhagic stroke. Recent studies in the author's laboratory indicate that brain capillary endothelium in vivo produces thrombomodulin (TM), a key cofactor in the TM-protein C system that is of major biological significance to the antithrombotic properties of the blood-brain barrier (BBB). The BBB endothelium also expresses tissue plasminogen activator (tPA), a key protein in fibrinolysis, and its rapid inhibitor, plasminogen activator inhibitor (PAI-1). The procoagulant tissue factor is normally dormant at the BBB. There is a vast body of clinical evidence to document the importance of hemostasis in the pathophysiology of brain injury. In particular, functional changes caused by major stroke risk factors in the TM-protein C, tPA/PAI-1, and tissue factor systems at the BBB may result in large and debilitating infarctions following an ischemic insult. Thus, correcting this hemostatic imbalance could ameliorate drastic CBF reductions at the time of ischemic insult, ultimately resulting in brain protection. Delineation of the molecular mechanisms of BBB-mediated hemostasis will likely contribute to future stroke prevention efforts and brain protection strategies.

Natriuretic Peptides Regulate the Expression of Tissue Factor and PAI-1 in Endothelial Cells

1999 ◽  
Vol 82 (11) ◽  
pp. 1497-1503 ◽  
Author(s):  
Hajime Tsuji ◽  
Hiromi Nishimura ◽  
Haruchika Masuda ◽  
Yasushi Kunieda ◽  
Hidehiko Kawano ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Tissue Factor ◽  
Plasminogen Activator ◽  
Natriuretic Peptide ◽  
Culture Media ◽  
Tissue Type ◽  
Dependent Manner ◽  
Ang Ii ◽  
Plasminogen Activator Inhibitor 1 ◽  
Pai 1

SummaryIn the present study, we demonstrate that brain natriuretic peptide (BNP) and C-type natriuretic peptide (CNP) interact with angiotensin II (Ang II) in regulative blood coagulation and fibrinolysis by suppressing the expressions of both tissue factor (TF) and plasminogen activator inhibitor-1 (PAI-1) induced by Ang II. The expressions of TF and PAI-1 mRNA were analyzed by northern blotting methods, and the activities of TF on the surface of rat aortic endothelial cells (RAECs) and PAI-1 in the culture media were respectively measured by chromogenic assay.Both BNP and CNP suppressed the expressions of TF and PAI-1 mRNA induced by Ang II in a time- and concentration-dependent manner via cGMP cascade, which suppressions were accompanied by respective decrease in activities of TF and PAI-1. However, neither the expression of tissue factor pathway inhibitor (TFPI) nor tissue-type plasminogen activator (TPA) mRNA was affected by the treatment of BNP and CNP.

Activated Protein C Increases Fibrin Clot Lysis by Neutralization of Plasminogen Activator Inhibitor No Evidence for a Cofactor Role of Protein S

1988 ◽  
Vol 60 (02) ◽  
pp. 328-333 ◽  
Author(s):  
N J de Fouw ◽  
Y F de Jong ◽  
F Haverkate ◽  
R M Bertina
Keyword(s):  
Plasminogen Activator ◽  
Protein C ◽  
Blood Platelets ◽  
Plasminogen Activator Inhibitor ◽  
Protein S ◽  
Tissue Type ◽  
Clot Lysis ◽  
Activator Inhibitor ◽  
Pai 1

summaryThe effect of purified human activated protein G (APC) on fibrinolysis was studied using a clot iysis system consisting of purified glu-plasminogen, tissue-type plasminogen activator, plasminogen activator inhibitor (released from endothelial cells or blood platelets), fibrinogen, 125T-fibrinogen and thrombin. All proteins were of human origin.In this system APC could increase fibrinolysis in a dose dependent way, without affecting fibrin formation or fibrin crosslinking. However, this profibrinolytic effect of APC could only be observed when plasminogen activator inhibitor (PAI-l) was present. The effect of APC was completely quenched by pretreatment of APC with anti-protein C IgG or di-isopropylfluorophosphate. Addition of the cofactors of APC:protein S, Ca2+-ions and phospholipid-alone or in combination did not enhance the profibrinolytic effect of APC. These observations indicate that human APC can accelerate in vitro clot lysis by the inactivation of PAI-1 activity. However, the neutralization of PAI-1 by APC is independent of the presence or absence of protein S, phospholipid and Ca2+-ions.

Potential Role of Adult Hippocampal Neurogenesis in Traumatic Brain Injury

2021 ◽  
Vol 28 ◽  
Author(s):  
Lucas Alexandre Santos Marzano ◽  
Fabyolla Lúcia Macedo de Castro ◽  
Caroline Amaral Machado ◽  
João Luís Vieira Monteiro de Barros ◽  
Thiago Macedo e Cordeiro ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Clinical Studies ◽  
Molecular Mechanisms ◽  
Hippocampal Neurogenesis ◽  
Cognitive Outcomes ◽  
Adult Hippocampal Neurogenesis ◽  
The Brain

: Traumatic brain injury (TBI) is a serious cause of disability and death among young and adult individuals, displaying complex pathophysiology including cellular and molecular mechanisms that are not fully elucidated. Many experimental and clinical studies investigated the potential relationship between TBI and the process by which neurons are formed in the brain, known as neurogenesis. Currently, there are no available treatments for TBI’s long-term consequences being the search for novel therapeutic targets, a goal of highest scientific and clinical priority. Some studies evaluated the benefits of treatments aimed at improving neurogenesis in TBI. In this scenario, herein, we reviewed current pre-clinical studies that evaluated different approaches to improving neurogenesis after TBI while achieving better cognitive outcomes, which may consist in interesting approaches for future treatments.

Abstract 267: A Single Dose of Reconstituted High Density Lipoprotein Reduces Expression of Tissue-Factor In Human Carotid Atherosclerotic Plaques

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Hosaam H Nasr ◽  
Ian M Loftus ◽  
Saiqa Sayed ◽  
Alun Jones ◽  
Evelyn Torsney ◽  
...  
Keyword(s):  
Single Dose ◽  
Tissue Factor ◽  
Plasminogen Activator ◽  
Clinical Event ◽  
Tissue Type ◽  
Transcriptional Level ◽  
Rt Pcr ◽  
Significant Difference ◽  
Plaque Stabilisation ◽  
Pai 1

Background: Multiple infusions of HDLs have been shown to mediate approximately 4% reduction in plaque volume. This may relate to removal of intra-plaque lipid, but the precise mechanism is unknown. To test the hypothesis that HDLs may influence plaque stabilisation through modulating transcription, we examined the effects of a single dose of rHDL on expression of thrombomodulatory genes in carotid plaques. Materials and Methods: Forty patients undergoing carotid endarterectomy (CEA) were stratified to three groups: early symptomatics ( n =12, stroke/transient ischemic attack (TIA) 1month before CEA)late symptomatics ( n =14, stroke/TIA > 1month before CEA); and asymptomatics ( n =12). RNA was isolated from plaques following CEA, and expression of the thrombomodulatory genes, tissue factor (TF); tissue factor pathway inhibitor (TFPI); thrombomodulin (TM); tissue type plasminogen activator (tPA); urokinase plasminogen activator (uPA); plasminogen activator inhibitor-1 (PAI-1), measured using QRT-RT-PCR. Nine patients with early symptomatic carotid disease, undergoing CEA, were then randomised to infusion of reconstituted HDL (rHDL) 80mg/kg Apo A-I ( n =4) or a similar volume of phosphate buffered saline ( n =5). Plaque specimens were collected 24 hrs later and RNA isolated for QRT-RT- PCR measurement of thrombomodulatory gene expression. Results: A significant difference in TF, TM, tPA and PAI-1 genes were observed in the 3 patient groups (see Table 1 ). In the rHDL group, a single dose of rHDL reduced the expression of TF (0.71 (0.65–0.75) vs 0.98 (0.81–1.14), P=0.05). No significant difference was observed in other thrombomodulatory factors between the 2 groups. Conclusions: Plaque stabilisation, which occurs within one month of a clinical event may be facilitated, at the transcriptional level, following rHDL infusion. We hope to report a larger double blind placebo controlled trial which will determine the full effects of rHDLs on plaque stability. Table 1

scholarly journals Screening of Biochemical and Molecular Mechanisms of Secondary Injury and Repair in the Brain after Experimental Blast-Induced Traumatic Brain Injury in Rats

2013 ◽  
Vol 30 (11) ◽  
pp. 920-937 ◽  
Author(s):  
Patrick M. Kochanek ◽  
C. Edward Dixon ◽  
David K. Shellington ◽  
Samuel S. Shin ◽  
Hülya Bayır ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Molecular Mechanisms ◽  
Secondary Injury ◽  
Injury And Repair ◽  
The Brain

Polymorphisms in Coagulant and Inflammatory Genes Modify the Phenotype of Severe Hemophilia A and B.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1009-1009 ◽  
Author(s):  
G. Jayandharan ◽  
Mercy Devadharshini ◽  
Auro Viswabandya ◽  
Sukesh C. Nair ◽  
R.V. Shaji ◽  
...  
Keyword(s):  
Tumor Necrosis Factor ◽  
Tissue Factor ◽  
Plasminogen Activator ◽  
Protein C ◽  
Tumor Necrosis ◽  
Hemophilia A ◽  
Tnf Alpha ◽  
Severe Hemophilia ◽  
Tgf Beta ◽  
Necrosis Factor

Abstract Among patients with severe hemophilia (<1% factor level), 10–15% are known to have a clinically mild phenotype. The basis for this phenomenon is unclear. We hypothesized that functionally significant polymorphisms in the coagulant, inflammatory and immunoregulatory genes may affect the phenotype of severe hemophilia. A total 114 patients with hemophilia A (n=95) and hemophilia B (n=19) were studied. All these patients were on minimal on-demand treatment. Patients were evaluated for the frequency and site of hemorrhage. Their clinical and radiological joint scores were documented. They were categorized as ‘mild’ (<1 affected joint and < 5 bleeds in the preceding year, n=15) or ‘severe’ (>1 affected joint and >5bleeds, n=99). Functional polymorphisms in the coagulant system (human platelet alloantigen; tissue factor; fibrinogen; factors II; V; VII; XIIIA; thrombin activable fibrinolysis inhibitor (TAFI); endothelial protein C receptor; endothelial nitric oxide synthase 3; tissue plasminogen activator; plasminogen activator inhibitor; tissue factor pathway inhibitor; protein C and S; thrombomodulin), known procoagulant factors (methylene tetrahydrofolate reductase gene), inflammatory cytokine genes (tumor necrosis factor alpha; transforming growth factor beta; interleukin (IL) 10; IL 6; IL 1beta; IL 1 beta receptor antagonist; tumor necrosis factor beta), immunoregulatory cytokine genes (interferon gamma; HLA B27; FC gamma receptor), MDM2, angiotensin converting enzyme and HFE genes were genotyped. The mean age in the two groups was 18.5 & 14.85, p=0.124. The clinical features showing significant difference are shown in the table. Of the polymorphisms studied, the FVII RQ/QQ (lower levels) (RR-3.99, p=0.022, 95% CI 1.2–13.4), TNF alpha-308AA/AG (pro-inflammatory) (RR-3.4, p=0.037, 95% CI, 1.07–10.7), TGF beta Codon 10 CC/CT (pro-inflammatory) (RR-2.8, p=0.07, 95% CI, 0.91–8.3), have been associated with a severe phenotype while MDM2GG (anti-inflammatory, RR-0.3, p=0.038, 95% CI, 0.1–0.93) was associated with a milder phenotype. We hypothesize that the bleeding frequency in severe hemophilia may be increased due to relatively lower FVII levels and a combination of cytokine driven pro-inflammatory state involving TNF alpha, TGF beta and MDM2 would cause destruction of the cartilage resulting in elaboration of metalloproteinases from chondrocytes leading to the development of arthropathy. Parameter Severe, n=99 Median (Range) Mild, n=15 Median (Range) p Value Number of bleeds /yr 15(3–74) 2(0–5) 0.000 Number of joints /yr 3 (1–6) 1 (0–1) 0.000 Age at first clinical symptom (months) 21(1–300) 60(6–90) 0.056 WFH clinical score 10 (0–27) 4 (0–21) 0.000 Pettersson score 13 (0–57) 6 (0–20) 0.001

Prospective Investigation of Hemostatic Parameters in Patients Undergoing Hematopoietic Stem Cell Transplantation.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 5302-5302
Author(s):  
Yue Han ◽  
Xiaoxu Lu ◽  
De Pei Wu ◽  
Aining Sun
Keyword(s):  
Stem Cell ◽  
Hematopoietic Stem Cell Transplantation ◽  
Stem Cell Transplantation ◽  
Plasminogen Activator ◽  
Cell Transplantation ◽  
Hematopoietic Stem Cell ◽  
Protein C ◽  
Conditioning Regimen ◽  
Hematopoietic Stem ◽  
Pai 1

Abstract Objective To illustrate the alteration of hemostatic parameters in recipients of hematopoietic stem cell transplantation (HSCT) and then determine its value in transplantation-related complications. Methods 45 patients receiving HSCT were evaluated prospectively in our institution. Hemostatic parameters were investigated prior to conditioning therapy and then weekly until five weeks after HSCT by enzymimmunoassay. Results Significant increase was observed in the levels of fibrinogen, tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) after transplant, while Protein C decreased significantly. No significant change existed in prothrombin time (PT), activated partial thromboplastin time (APTT) and antithrombin III (ATIII) levels. Six patients with acute grades II–IV graft-versus-host disease (aGVHD) presented with significantly lower level of Protein C compared with those who had grades 0–I aGVHD, PAI-1 level didn’t change apparently as well as fibrinogen and t-PA in the same time. However, three patients with veno-occlusive disease (VOD) extremely showed elevated PAI-1 levels after the clinical onset of VOD by comparison with mean post-HSCT values in the non-VOD patients; similar result was found in the patient who developed thrombotic microangiopathy (TMA). Conclusion Our results suggest hemostatic imbalance is one important manifestation during HSCT, reflecting prothrombotic states and endothelial damage, which may be caused by the conditioning regimen and/or transplantation-related complications. The extreme elevation of PAI-1 alteration may be useful to recognize the development of VOD and TMA, while Protein C diminution facilitates the early diagnosis of aGVHD.

scholarly journals Insulin Inhibits the Pro-Inflammatory Transcription Factor Early Growth Response Gene-1 (Egr)-1 Expression in Mononuclear Cells (MNC) and Reduces Plasma Tissue Factor (TF) and Plasminogen Activator Inhibitor-1 (PAI-1) Concentrations

2002 ◽  
Vol 87 (3) ◽  
pp. 1419-1422 ◽  
Author(s):  
Ahmad Aljada ◽  
Husam Ghanim ◽  
Priya Mohanty ◽  
Neeti Kapur ◽  
Paresh Dandona
Keyword(s):  
Transcription Factor ◽  
Tissue Factor ◽  
Plasminogen Activator ◽  
Growth Response ◽  
Plasminogen Activator Inhibitor ◽  
Early Growth ◽  
Plasminogen Activator Inhibitor 1 ◽  
Early Growth Response ◽  
Activator Inhibitor ◽  
Pai 1

We have recently demonstrated that an infusion of a low dose of insulin reduces the intranuclear NF-κB (a pro-inflammatory transcription factor) content in MNC while also reducing the p;asma concentration of NF-κB dependent pro-inflammatory cytokines and adhesion molecules. We have now tested the effect of insulin on the pro-inflammatory transcription factor, early growth response-1 (Egr-1) and plasma concentration of tissue factor (TF) and plasminogen activator inhibitor-1 (PAI-1), two major proteins whose expression is modulated by Egr-1. Insulin was infused at the rate of 2 IU/h in 5% dextrose (100 mL/h) and KCI (8 mmol/h) for 4 h in the fasting state in ten obese subjects. Blood samples were obtained at 0, 2, 4 and 6 h. MNC were isolated and their total homogenates and nuclear fractions were prepared and Egr-1 was measured by electrophoretic mobility shift assay (EMSA). Plasma TF and PAI-1 were assayed by ELISA. There was a significant fall in Egr-1 at 2 (66 ± 14% of basal level) and 4 h (47± 17% of the basal level; P<0.01). PAI-1 levels (basal = 100%) decreased significantly after insulin infusion at 2 h (57 ± 6.7% of the basal level) and at 4 h (58 ± 8.3% of the basal level; P<0.001). Plasma TF levels (basal = 100%) decreased to 76 ± 7.7% of the basal level at 2 h and to 85 ± 10.4% of the basal level at 4 h (P<0.05). Thus, insulin reduces intranuclear Egr-1 and the expression of TF and PAI-1. These data provide further evidence that insulin has an anti-inflammatory effect including the inhibition of TF and PAI-1 expression. These effects suggest a potential beneficial effect of insulin in thrombin formation and fibrinolysis in atherothrombosis.

A global assay of haemostasis which uses recombinant tissue factor and tissue-type plasminogen activator to measure the rate of fibrin formation and fibrin degradation in plasma

2007 ◽  
Vol 98 (10) ◽  
pp. 871-882 ◽  
Author(s):  
Kun Zhu ◽  
Mika Skeppholm ◽  
Jenny Vedin ◽  
Jan Svensson ◽  
Nils Egberg ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Plasminogen Activator ◽  
Coagulation Cascade ◽  
Tissue Type ◽  
Thrombin Inhibitor ◽  
Tissue Type Plasminogen Activator ◽  
Fibrin Formation ◽  
Minimal Dose ◽  
Type Plasminogen Activator ◽  
Pai 1

SummaryThe global assay of Overall Haemostasis Potential we previously described has been refined. The coagulation cascade in plateletpoor plasma is triggered by adding a minimal dose of recombinant tissue factor together with purified phospholipids and calcium; fibrinolysis is initiated by adding recombinant tissue type-plasminogen activator in a concentration similar to what can be obtained during thrombolysis. Numerical differentials of optical densities reflecting rates of fibrin formation and degradation are calculated by a new software, and the Coagulation Profile (Cp) and the Fibrinolysis Profile (Fp) are determined. The combined effect of these counteractive systems is expressed as a ratio of Cp to Fp, called the Overall Haemostasis Index. Commercially available coagulant-deficient patient plasma samples and plasma with various amounts of added PAI-1 are examined; changes of fibrin turbidity demonstrate that this assay can determine Cp and Fp in a physiologically relevant way. Increased Cp and decreased Fp in prothrombotic patients, as well as expected effects of heparin or a thrombin inhibitor on Cp and Fp, suggest that our method can detect hypercoagulability and assist in monitoring antithrombotic treatment. Ongoing studies will show whether this simple assay can be of value in clinical routine.

scholarly journals A comparison between activated protein C and des-1-41-light chain- activated protein C in reactions with type 1 plasminogen activator inhibitor

Blood ◽  
1989 ◽  
Vol 74 (1) ◽  
pp. 173-181
Author(s):  
CL Gladson ◽  
RR Schleef ◽  
BR Binder ◽  
DJ Loskutoff ◽  
JH Griffin
Keyword(s):  
Plasminogen Activator ◽  
Light Chain ◽  
Protein C ◽  
Activated Protein C ◽  
Plasminogen Activator Inhibitor ◽  
Amidolytic Activity ◽  
Gla Domain ◽  
Activator Inhibitor ◽  
Pai 1

This study investigates the role of the gamma-carboxyglutamic acid (gla) containing domain of activated protein C in interactions with both platelet-derived and purified type 1 plasminogen activator inhibitor (PAI-1). The activity of human platelet PAI-1 was neutralized to the same extent by bovine activated protein C and bovine des-1–41- light chain-activated protein C. Both forms of activated protein C formed SDS-stable, divalent-cation independent complexes with platelet PAI-1, as demonstrated by immunoblotting using antibodies directed to either protein C or PAI-1. Since activated protein C neutralized PAI-1, the potential inhibition of the enzyme by PAI-1 was studied. Purified PAI-1 inhibited the amidolytic activity of bovine-activated protein C and bovine des-1–41-light chain-activated protein C with a k2 of 2.85 X 10(4) M-1 sec-1 for both proteins. These data suggest that the gla domain of activated protein C is not required for neutralization of PAI- 1 activity, for complex formation with PAI-1, or for inhibition of the amidolytic activity of activated protein C by PAI-1.

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