bluuebunny/crossref_metadata_2025 huggingface dataset:
Angiogenesis in Ischemic Disease
Authors: Risau Werner , Marti Hugo H.
Published: March 2018

Angiogenic growth factors and their endothelial receptors function as major regulators of blood vessel formation. The VEGF/VEGFR and the Angiopoietin/Tie2 receptor systems represent key signal transduction pathways involved in the regulation of embryonic vascular development. Inactivation of any of the genes encoding these molecules results in defective vascular development and lethality between embryonic day 8.5 and 12.5. In addition, VEGF and its receptors are also critically involved in the regulation of pathological blood vessel growth in the adult during various angiogenesis-dependent diseases that are associated with tissue hypoxia, such as solid tumor growth and ischemic diseases. It is now well established that therapeutic angiogenesis can be achieved in animal models of hind limb and myocardial ischemia by exogenously adding VEGF and/or other angiogenic growth factors. Available clinical data from human trials also suggests that patients with severe cardiovascular diseases could potentially benefit from such therapies. However, much more work needs to be done to compare the potency of different angiogenic factors or the combination thereof, as well as the best way of delivery, either as recombinant proteins, as naked DNA or via adenoviral vectors. Nevertheless, the therapeutic efficacy of simply injecting naked plasmid DNA or proteins into ischemic tissue to deliver secreted angiogenic factors is an encouraging finding. Time will show whether the adverse side effects of therapeutic angiogenesis, mainly vascular permeability and edema formation, can be minimized and angiogenic factors can be used as an effective therapy in patients for the treatment of ischemic diseases such as arterial occlusive disease, myocardial infarction, and, eventually, also stroke.
Unstable Angina in 1998
Authors: Lichtlen P. R.
Published: March 2018

Unstable angina (UA) and non-Q-wave myocardial infarction (NQWMI) are acute coronary syndromes with repeated, severe ischemic events of short duration. These events are mainly due to a rapid decrease
in coronary blood flow, and to a rapid, reversible reduction of the arterial lumen in localized areas. Episodes often are a mixture of thrombus formation due to platelet aggregation and localized spasm, leading to vasoconstriction. Due to the short interval (minutes) of ischemic events, usually no or minimal irreversible myocardial damage takes place.

The main goal of treatment is to prevent progression of this unstable situtation into a myocardial infarction. In the majority of cases, this is possible with adequate treatment of vasodilatory substances like nitrates, long-acting dihydropyridines like amlodipine and betablockers. In addition heparin and particular antiaggregatory drugs inhibiting platelet activation by blocking the GPIIb/IIIa receptor, the common pathway for platelet aggregation, are applied to prevent thrombus formation. This, in the majority of cases allows a passivation of the acute situtation, leaving time to undertake possible further steps as coronary angiography, eventually followed by PTCA of the culprit lesion or, in advanced cases of CAD, by CABG with complete revascularization.
Acute Myocardial Infarction: Selection of Reperfusion Strategies in the Individual Patient
Authors: Senges Jochen , Schiele Rudolf
Published: March 2018

The selection of the reperfusion therapy (thrombolysis, PTCA, or no reperfusion) in acute myocardial infarction should depend on the riskbenefit ratio, the availability, and the costs. Thrombolysis is available everywhere and is the standard of reperfusion therapy, but carries the risk of intracranial haemorrhage. PTCA is more effective with less risk, but it is also more expensive and available only in specialised centres. In current clinical practise in Germany, the only important determinant for using PTCA as a reperfusion strategy is the availability of a catheter laboratory. Besides availabilty, the selection of reperfusion therapy should be made more on clinical relevance: (i) PTCA especially in patients with a large benefit, the presence of contraindications to thrombolysis, or in cardiogenic shock, and (ii) thrombolysis, if PTCA is not immediately available.
Vectorcardiography: A Tool for Non-invasive Detection of Reperfusion and Reocclusion?
Authors: Eriksson Sven V.
Published: March 2018

In acute myocardial infarction, the perfusion status frequently fluctuates with rapid occurrences of coronary occlusion followed by myocardial ischemia. In patients with unstable angina, most episodes of ischemia are not accompanied by chest pain. In these patients it is important to be able to monitor the results of medical treatment non-invasively to establish the need for further intervention. It is not feasible to perform coronary angiography in all patients with acute myocardial infarction to evaluate patency of the infarct-related artery. Furthermore, even in a patent artery, no reflow may be present in the myocardial tissue. Angiography is therefore not the perfect golden standard to compare noninvasive ischemia monitoring with. Prognosis seems to be a better standard for comparison. This review indicates that vectorcardiography monitoring may identify myocardial reperfusion at an early
stage and gives valuable prognostic information both in patients with unstable angina and acute myocardial infarction with low interobserver variability.
Ventricular Remodeling after Acute Myocardial Infarction
Authors: Osterziel K. J. , Willenbrock R. , Gulba D. C. , Harsdorf R. v. , Dietz R.
Published: March 2018

The term ventricular remodeling has been coined to describe the geometrical changes in size and shape of the left ventricle occurring after large myocardial infarcts.

We do not exactly know what initiates this process. Slipping of myofilaments following destruction of connective tissue – probably due to metalloproteinase activation – could be the initial event.

As a consequence, wall stress is increased triggering deleterious adaptation processes, such as

– intracardiac angiotensin II generation

– cardiac endothelin formation and release

– pro-apoptotic signals for cardiomyocytes

– hypertrophic signals for fibroblasts and cardiomyocytes

This cascade of events is not only observed in the process of remodeling following myocardial infarction but is also operating during the progression of heart failure.

Therapeutic principles therefore are similar in both conditions:

– reduction of wall stress (pharmacological or mechanical unloading of the heart)

– blockade of angiotensin II generation or of AT1-receptors (ACEinhibitors or AT1 antagonists)

– blockade of endothelin receptors (ETA-blockers)

– blockade of adrenergic receptors (preferably β1-adrenergic receptor blockers).

Better understanding of the molecular mechanisms of the remodeling process already has fueled the search for new therapeutic interventions (such as endothelin receptor blockers, aldosterone antagonists and growth hormone application). Continuous research in this field may be especially rewarding if we will succeed in identifying the very first step in the cascade.
Activation Markers of Coagulation and Fibrinolysis: Alterations and Predictive Value in Acute Coronary Syndromes
Authors: Heller Wolfgang , Seipel Ludger , Hoffmeister Hans Martin
Published: March 2018

Several alterations of the coagulation, of the fibrinolysis and of inflammation are known in patients with acute coronary syndromes. To extent current knowledge of the pathopysiology and to optimize therapeutical strategies, the new molecular markers can be used in clinical studies. Furthermore, several studies were undertaken to assess the prognostic value of activation markers of these systems for patients with unstable angina pectoris and acute myocardial infarction with or without thrombolytic therapy. The majority of studies focussed on markers of thrombin activation, fibrinogen, fibrin degradation products and t-PA and its main inhibitor PAI-1. While there are stimulating results from larger studies, the value for prognosis for the individual patient still is limited by the overlap of patients with good versus a poor outcome.
Oral Anticoagulation after a First Episode of Venous Thromboembolism: How Long? How Strong?
Authors: Watzke H. H.
Published: March 2018

A number of studies have been published in the last years which shed light on the optimal intensity and the optimal duration of oral anticoagulation in patients with venous thrombosis.

Based on these studies it is now generally recommended to treat patients with venous thromboembolism at an INR ranging from 2.0 to 3.0. The optimal duration of anticoagulation mainly depends on the nature of the thrombotic event. In patients with a temporary prothrombotic risk factor such as surgery, immobilization or trauma a relatively short duration of oral anticoagulation (3-6 months) is generally recommended. Patients with idiopathic venous thromboembolism require a considerably longer duration of anticoagulation (6 months at least).
Platelet Function Inhibitors in the Year 2000
Authors: Mousa Shaker , Bennett Joel
Published: March 2018

Platelet thrombi are responsible for much of the morbidity and mortality of arterial vascular disease (1). Because platelet inhibitors such as aspirin have proven to be of benefit to patients with these disorders, there has been a directed search for more potent anti-platelet agents. The following discussion addresses the mechanism of action and clinical utility of the currently available platelet function inhibitors. Although in theory these agents could impair platelet adhesion, aggregation, secretion, or platelet procoagulant activity, in practice they are focused almost exclusively on the biochemical events that proceed from platelet stimulation to ligand binding to the platelet fibrinogen receptor GPIIb-IIIa.
The Incidence of Deep Venous Thrombosis and Pulmonary Embolism among Patients with Inflammatory Bowel Disease: A Population-based Cohort Study
Authors: Blanchard James , Houston Donald , Wajda Andre , Bernstein Charles
Published: March 2018

Background: There is an impression mostly from specialty clinics that patients with inflammatory bowel disease (IBD) have an increased risk of venous thromboembolic disorders. Our aim was to determine the incidence of deep venous thrombosis (DVT) and pulmonary embolism (PE) from a population-based database of IBD patients and, to compare the incidence rates to that of an age, gender and geographically matched population control group.

Methods: IBD patients identified from the administrative claims data of the universal provincial insurance plan of Manitoba were matched 1:10 to randomly selected members of the general population without IBD by year, age, gender, and postal area of residence using Manitoba Health’s population registry. The incidence of hospitalization for DVT and PE was calculated from hospital discharge abstracts using ICD-9-CM codes 451.1, 453.x for DVT and 415.1x for PE. Rates were calculated based on person-years of follow-up for 1984-1997. Comparisons to the population cohort yielded age-adjusted incidence rate ratios (IRR). Rates were calculated based on person-years of follow-up (Crohn’s disease = 21,340, ulcerative colitis = 19,665) for 1984-1997.

Results: In Crohn’s disease the incidence rate of DVT was 31.4/10,000 person-years and of PE was 10.3/10,000 person-years. In ulcerative colitis the incidence rates were 30.0/10,000 person-years for DVT and 19.8/10,000 person-years for PE. The IRR was 4.7 (95% CI, 3.5-6.3) for DVT and 2.9 (1.8-4.7) for PE in Crohn’s disease and 2.8 (2.1-3.7) for DVT and 3.6 (2.5-5.2) for PE, in ulcerative colitis. There were no gender differences for IRR. The highest rates of DVT and PE were seen among patients over 60 years old; however the highest IRR for these events were among patients less than 40 years.

Conclusion: IBD patients have a threefold increased risk of developing DVT or PE.
Interpreting the International Normalized Ratio (INR) in Individuals Receiving Argatroban and Warfarin
Authors: DiCicco R.A. , Hursting M.J. , Montague T. , Jorkasky D.K. , Sheth S.B.
Published: March 2018

The effects of argatroban, a direct thrombin inhibitor, on the International Normalized Ratio (INR), activated partial thromboplastin time (aPTT) and functional factor X during warfarin co-administration were established to provide means to interpret INRs during argatroban/warfarin co-therapy. Twenty-four subjects receiving warfarin (7.5 mg, day 1; 3-6 mg/day, days 2-10) and argatroban (1-4 μg/kg/min over 5 h, days 1-11) were assessed daily for these coagulation parameters prior to argatroban infusion (warfarin “monotherapy”) and at its conclusion (“co-therapy”). Argatroban increased aPTTs dose-dependently. Co-therapy INR increased linearly with monotherapy INR, with slope sensitive to argatroban dose and thromboplastin used. Prediction errors for monotherapy INRs were ≤± 0.4 for argatroban 1-2 μg/kg/min but ≥± 1.0 for higher doses. Despite co-therapy INRs >7, no major bleeding occurred. Factor X remained ≥37% of normal. Therefore, the predictable effect of argatroban (≤ 2 mg/kg/min only) on INRs during warfarin co-therapy allows for reliable prediction of the level of oral anticoagulation.
Rho-kinase Is Involved in the Sustained Phosphorylation of Myosin and the Irreversible Platelet Aggregation Induced by PAR1 Activating Peptide
Authors: Missy K. , Plantavid M. , Viala C. , Chap H. , Pacaud P. , Payrastre B.
Published: March 2018

We have addressed the role of Rho-kinase in the different steps of thrombin receptor agonist peptide (TRAP) -induced platelet activation. Interestingly, under physiological conditions, incubation of platelets with increasing concentrations of the specific Rho-kinase inhibitor Y-27632 resulted in a dose-dependent reversion of the aggregation induced by 10 μM TRAP, without affecting serotonin secretion. Addition of Y-27632 after three minutes of TRAP stimulation, when the maximal aggregation was reached, resulted in a rapid disaggregation of platelets. Accordingly, the early peak of myosin light chain (MLC) phosphorylation induced by TRAP was not affected by Y-27632 but its sustained phosphorylation, observed during the irreversible phase of aggregation, was dependent of Rho-kinase activity. The rapid decrease in MLC phosphorylation upon Y-27632 treatment correlated well with the specific disappearance of myosin heavy chain from the cytoskeleton and preceded platelet disaggregation. Finally, we provide evidence that secreted ADP, known to play a key role in TRAP-induced irreversible phase of aggregation, was involved in the sustained MLC phosphorylation through Rho-kinase and could be replaced by epinephrine.
Biochemistry and Physiology of Blood Coagulation
Authors: Mann Kenneth
Published: March 2018

Introduction

The biochemical investigation of a biological process can be divided into three segments. The first is the development of an inventory of the components involved in the process, the second is the establishment of the connectivity between components, and the third is the establishment of the dynamics of the processes as they occur in the living organism.
Regulation of Factor VIIIa in the Intrinsic Factor Xase
Authors: Fay Philip
Published: March 2018

Introduction

Hemophilia A, the most common of the severe, inherited bleeding disorders, results from a deficiency or defect in the plasma protein factor VIII. The activated form of the protein serves as an essential cofactor for factor IXa in the conversion of factor X to factor Xa. This surface-bound complex of enzyme and cofactor is referred to as the intrinsic factor Xase. Factor VIIIa dramatically increases the catalytic rate constant for substrate conversion by an unclear mechanism. The activity and stability of the factor Xase appears to be regulated by the integrity of the cofactor. Factor VIIIa possesses a labile structure, and subunit dissociation results in the decay of Xase activity. Furthermore, factor VIIIa is a substrate for proteolytic inactivation by several enzymes, including factor IXa, the enzyme for which it serves as a cofactor. Although interest in the structure, function, and metabolism of factor VIII is commensurate with its biochemical and clinical importance, the molecular basis for its role in coagulation and the regulation of function through complex intramolecular and intermolecular interactions remain poorly understood.
Mechanisms of Signaling through Urokinase Receptor and the Cellular Response
Authors: Koshelnick Yuri , Ehart Monika , Stockinger Hannes , Binder Bernd
Published: March 2018

Introduction

The urokinase-urokinase receptor (u-PA-u-PAR) system seems to play a crucial role in a number of biological processes, including local fibrinolysis, tumor invasion, angiogenesis, neointima and atherosclerotic plaque formation, inflammation, and matrix remodeling during wound healing and development.1-6 Binding of urokinase to its specific receptor provides cells with a localized proteolytic potential. It stimulates conversion of cell surface-bound plasminogen into active plasmin, which, in turn, is required for proteolytic degradation of basement membrane components, including fibronectin, collagen, laminin, and proteoglycan core proteins.7 Moreover, plasmin activates other matrix-degrading enzymes, such as matrix metalloproteinases.8 Overexpression of u-PA/u-PAR correlates with tumor invasion and metastasis formation,9-13 while reduction of cell-surface bound u-PA and inhibition of u-PAR expression leads to a significant decrease of invasive and metastatic activity.14 Specific antagonists that suppress binding of u-PA to u-PAR have been shown to inhibit cell-surface plasminogen activation, tumor growth, and angiogenesis both in vitro and in vivo models.15,16

Independently of its proteolytic activity, u-PA is implicated in many biological processes that seem to require u-PAR-mediated intracellular signal transduction, such as proliferation, chemotactic movement and adhesion, migration, and differentiation.17 Data obtained in the late 1980s indicated that u-PA not only provides cells with local proteolytic activity, but might also be capable of transducing signals to the cell.18-22 At that time, however, the u-PAR has just been isolated, cloned, and identified as a glycosylphosphatidylinositol (GPI)-linked protein and not a transmembrane protein. Signaling via the u-PAR was, therefore, regarded as being unlikely, and the effects of u-PA on cell proliferation18-22 were thought to be mediated by proteolytic activation of latent growth factors. The assumption of direct signaling via u-PAR was, in fact, considered controversial, until about 10 years later when a physical association between u-PAR and signaling proteins was found.23 From this report on, several proteins associated with u-PAR have been identified. Now, u-PAR seems to be part of a large “signalosome” associated and interacting with several proteins on both the outside and inside of the cell.
Cyclic Nucleotide Phosphodiesterases and Human Arterial Smooth Muscle Cell Proliferation
Authors: Rybalkin Sergei , Bornfeldt Karin
Published: March 2018

Introduction

Smooth muscle cells (SMCs) in the arterial wall are normally found in a contractile, nonproliferative state. These SMCs are continuously exposed to agents that elevate cyclic AMP (cAMP) and cyclic GMP (cGMP), such as prostacyclin and nitric oxide (NO) released from the endothelium. Both cAMP and cGMP potently inhibit SMC proliferation by antagonizing major signaling pathways induced by growth factors, such as platelet-derived growth factor. Different forms of injury to the endothelium result in proliferation of the SMCs and can develop into atherosclerosis, restenosis, or arterial thickening associated with neonatal pulmonary hypertension. In human adult aorta, cAMP and cGMP levels are tightly regulated by synthesis and degradation. The latter is mediated by at least two different cAMP phosphodiesterases (PDEs), PDE3 and PDE4, and three different PDEs that degrade mainly cGMP, PDE1A, PDE1B, and PDE5. Strikingly, expression of a new PDE that degrades both cAMP and cGMP, PDE1C, is markedly induced in proliferating SMCs from the same aorta in culture, whereas its expression is nondetectable in contractile aorta. We propose that, for a human arterial SMC to be able to efficiently proliferate, and perhaps even to undergo a phenotypic change from a quiescent to a proliferative phenotype, it has to efficiently degrade inhibitory cAMP and cGMP. In human SMCs, PDE1C is induced to degrade these cyclic nucleotides. Understanding the role of PDE1C in SMC proliferation may provide the basic information necessary for development of highly specific PDE1C inhibitors that target proliferating SMCs in cardiovascular disease.
Antibody-Mediated Disruption of the Annexin-V Antithrombotic Shield: A New Mechanism for Thrombosis in the Antiphospholipid Syndrome
Authors: Wu Xiao-Xuan , Rand Jacob
Published: March 2018

Introduction

The antiphospholipid (aPL) syndrome is a condition that manifests in patients as vascular thromboembolism or recurrent pregnancy loss together with laboratory evidence for the presence of antibodies against anionic phospholipid-protein complexes. For a recent comprehensive review, the reader is referred to Hughes et al.1 The syndrome was first proposed to be a distinct entity, called anticardiolipin syndrome, in 1985,2 and was later renamed antiphospholipid syndrome.3 The disorder was classified as “primary” in the absence of a concurrent autoimmune condition, such as systemic lupus erythematosus, or “secondary” in the presence of another such autoimmune disorder. Antiphospholipid antibodies are detected by their reactivity to anionic phospholipids (or protein-phospholipid complexes) in solid phase immunoassays, or by their inhibition of phospholipid-dependent coagulation reactions, known as the “lupus anticoagulant” effect. The ever-expanding, yet still insufficiently integrated, knowledge of this enigmatic disorder makes this area an intriguing subject for investigation.

The pathophysiologic mechanism of this syndrome has remained obscure, resulting from the apparent multiplicity of antigenic determinants recognized by the antibodies. In addition, a large number of effects1 have been described for the antibodies in vitro and in cell culture systems. These effects, which include the paradoxical lupus anticoagulant (LAC) phenomenon, are a consequence of the numerous roles played by phospholipids in the hemostasis system and in a multitude of biologic processes. The purpose of this review is to introduce the reader to the current state of knowledge of the role of annexin-V in this disorder.
Recombinant Thrombomodulin and Activated Protein C in the Treatment of Disseminated Intravascular Coagulation
Authors: Maruyama Ikuro
Published: March 2018

Introduction

The blood coagulation cascade is regulated by the luminal surface of the endothelial cell lining.1 Endothelial cells synthesize tissue factor pathway inhibitor (TFPI), which, in part, binds to the cell surface glycosaminoglycans and inhibits factors Xa, VIIa, and tissue factor.2 Endothelial cells also produce and exhibit thrombomodulin (TM) on their luminal surface.3 TM is a kind of thrombin receptor that forms a 1:1 complex with thrombin. In this complex, thrombin activates protein C (PC) more than 1,000-fold more than thrombin alone. TM then loses its procoagulant activities, which include fibrinogen clotting, activation of factors V and VIII, and platelet activation. Thus, TM converts thrombin from a procoagulant protease to an anticoagulant. Pathologic states, such as an endothelial injury or perturbation or continuous rapid coagulation cascade activation, overcomes the endothelial regulating activity, resulting in the development of intravascular coagulation and the induction of disseminated intravascular coagulation (DIC). Theoretically, then, supplementing soluble TM or activated PC (APC) to reconstitute the endothelial coagulation regulation system in the circulation and regulate pathologically-activated blood coagulation could be beneficial. In this chapter, application of soluble TM and APC in the treatment of DIC is reviewed.
Redox Signals that Regulate the Vascular Response to Injury
Authors: Berk Bradford
Published: March 2018

Introduction

Reactive oxygen species (ROS), generated by a variety of extracellular and intracellular mechanisms, are novel signal mediators that regulate signal transduction events. In this discussion, ROS will refer to H2O2, O2-, and OH-. Data suggest that, following vascular injury, ROS production is increased. These ROS activate signal events that are required for the repair process. Three key findings from our laboratories support the concept that oxidative stress is an important stimulus in the vessel wall for vascular repair, vascular smooth muscle cell (VSMC) growth, and vascular lesion formation. First, following oversized balloon inflation-induced porcine coronary artery injury, there is increased production of oxygen radicals (O2-, H2O2, and OH-) in the vessel wall for several weeks.1 Second, administration of several antioxidants including probucol, vitamins C and E, and L-cysteine decreases neointimal proliferation and/or promotes vessel remodeling in pig and rat injury models.1-3 Third, in vitro, we have shown that ROS stimulate VSMC growth and activate signal events typical of VSMC mitogens.4,5

A scheme for the mechanism by which oxidative stress is proposed in Figure 1. The initial vascular injury produced by balloon inflation rapidly increases the local concentration of ROS, which stimulate further generation of ROS by multiple mechanisms including xanthine oxidase, NADH oxidase, phospholipases, and mitochondrial electron transport dysfunction. In the setting of VSMC growth stimulation (by platelet and VSMC-derived mitogens) and cytokine stimulation (by leukocytes), there is amplification of ROS generating systems. These processes cause the cellular redox state to become more oxidized. This establishes a self-perpetuating increase in ROS production. Next, changes in cellular redox state stimulate growthrelated signal transduction events. Until recently, VSMC growth was thought to be mediated largely by peptide growth factors. Published data from our laboratory show that ROS increase intracellular calcium, activate protein kinases, increase protooncogene expression, and stimulate DNA synthesis mitogens.4-6 However, the specific mechanisms by which the sustained oxidative stress present in the injured vessel stimulates VSMC growth remain undefined. Data presented indicate that redox sensitive signal pathways may be defined by specific activation of upstream mediators, which include phospholipases, small G proteins, and tyrosine kinases. Final effectors include serine-threonine kinases, such as the mitogen activated protein (MAP) kinases that activate specific transcription factors.
Treatment of Venous Thromboembolism
Authors: Bates Shannon , Hirsh Jack
Published: March 2018

Introduction

Venous thromboembolism (VTE), which includes deep vein thrombosis (DVT) and pulmonary embolism (PE), is a common clinical problem. If untreated or inadequately treated, there is a high risk of fatal PE1 and recurrent venous thrombosis.2-4 The objectives of treatment are to prevent local extension of thrombus, embolization, and recurrent thrombosis.

It is now widely accepted that VTE is a single disorder and, therefore, the treatment of venous thrombosis and PE is essentially the same. Four treatment modalities are available. Anticoagulant therapy prevents the growth of an existing thrombus or embolus, thrombolytic therapy accelerates the rate of dissolution of thrombi or emboli, caval interruption intercepts venous thrombi that break off and embolize, thereby preventing dangerous PE, and surgical therapy removes thrombi or emboli.
Do Heparins Do More than Just Treat Thrombosis? The Influence of Heparins on Cancer Spread
Authors: Hettiarachchi Rohan , Smorenburg Susanne , Ginsberg Jeffrey , Levine Mark , Prins Martin , Büller Harry
Published: March 2018

Introduction

The influence of unfractionated heparin (UFH) and other anticoagulants on the spread of cancer has been reported since the early 1960s.1 However, clinical studies investigating the use of heparins in cancer patients have not produced consistent results.2 Intravenous, adjusted-dose UFH for 5 to 10 days has been the standard initial treatment for venous thrombosis. More recently, subcutaneous, fixed-dose, low molecular weight heparins (LMWHs), which are fractions of the parent compound, have been shown to be safe and effective alternatives to UFH in the initial treatment for venous thromboembolism.3-5

In one of our randomized clinical trials comparing LMWH and UFH in the initial treatment of deep vein thrombosis (DVT), we observed an unexpected difference in 6-month mortality among cancer patients in favor of LMWH, which could not be attributed to a difference in the incidence of thrombotic or bleeding complications.6 A similar observation in favor of LMWH was reported in a subsequent study and in a meta-analysis of trials.7,8 The number of cancer patients included in these studies was small, and adjustment of the observed effect for the baseline characteristics of the cancer patients was not possible. However, these findings suggested an inhibitory effect of LMWH on tumor growth or metastasis, which is less apparent or absent for UFH, resulting in a beneficial effect on the survival of cancer patients. This hypothesis is supported by the observations, in experimental studies, that LMWH and low molecular weight heparan sulfate, in comparison to UFH, effectively suppressed angiogenesis, a process necessary for tumor growth and metastasis.9,10

On the other hand, animal studies that investigated the effect of chemically-modified heparins on the spread of cancer did not detect a superior anti-tumor effect of LMWH compared to UFH; both were found to inhibit metastasis.11,12 To date, the effect of LMWH on cancer survival in humans has not been investigated as a primary objective. If a consistent and beneficial effect of LMWH on mortality is indeed present, such a study would be warranted.

We performed a meta-analysis of all available randomized clinical trials where LMWH was compared with UFH in the treatment of venous thromboembolism (VTE) to estimate the crude treatment effect of LMWH on mortality in cancer patients compared to UFH. Subsequently, we adjusted this treatment effect for age, gender, and primary malignancy site by reanalyzing data from three of those trials.3-5 This effect was further adjusted for other prognostic factors, including cancer histology, tumor stage, presence of metastases, duration of cancer, and concomitant use of cancer treatment, by analyzing individual patient data from the largest randomized trial.5
A Comparison of Danaparoid and Lepirudin in Heparin-induced Thrombocytopenia
Authors: Farner B. , Eichler P. , Kroll H. , Greinacher A.
Published: March 2018

Heparin-induced thrombocytopenia (HIT) is a hypercoagulable syndrome strongly associated with thrombosis that is usually treated with drugs that inhibit factor Xa (danaparoid) or thrombin (lepirudin). In the present study the outcome of HIT-patients treated with danaparoid or lepirudin was compared using the single or combined endpoints of new thromboembolic complications (new TECs), amputations and/or death, and major bleeding. HIT-patients treated with lepirudin were enrolled in two prospective trials and patients, who were identified in the same two laboratories during the same time period, who were not enrolled into these studies but treated with danaparoid, were assessed retrospectively according to a standardized questionnaire. 126 danaparoid (60.3% female) and 175 lepirudin treated patients (58.3% female) fulfilled the same inclusion and exclusion criteria. In a time-to-eventanalysis the cumulative risk of combined endpoint was higher in HIT-patients without thromboembolic complication at baseline treated with danaparoid (usually in prophylactic dose 750 anti-factor Xa units b.i.d. or t.i.d. s.c.) as compared to lepirudin (aPTT adjusted) (P = 0.020). Whereas HIT-patients with TEC at baseline who were usually treated with therapeutic dose had a similar outcome in both treatment groups (P = 0.913). Major bleeding occurred in 2.5% (95% CI 0.5-7.0%) of danaparoid treated patients as compared to 10.4% (95% CI 6.3-15.9%) of lepirudin treated patients until day 42 (P = 0.009). This indicates that the efficacies of therapeutic doses of danaparoid or lepirudin in preventing death, amputation or new TEC in HIT-patients do not differ largely, but the risk of bleeding seems to be higher in lepirudin treated patients. The prophylactic dose of danaparoid approved in the European Union for HIT without TEC at baseline seems suboptimal. A prospective comparative trial is required to verify these preliminary conclusions.
Von Willebrand Factor-cleaving Protease in Childhood Diarrhoea-associated Haemolytic Uraemic Syndrome
Authors: Lämmle Bernhard , Nevard Corinne , Haycock George , Furlan Miha , Hunt Beverley
Published: March 2018

A deficiency of von Willebrand factor (vWF)-cleaving protease, either due to a congenital deficiency or to the presence of a protease inhibitor of vWF-cleaving protease has been associated with thrombotic thrombocytopenic purpura (TTP). We have studied vWF-cleaving protease in diarrhoea-associated haemolytic uraemic syndrome (D+ HUS), which shares clinical features with TTP. 29 children with acute D+ HUS and 13 control children were studied.

vWF-cleaving protease activity was normal (range 50-150%) in 39 of 42 plasma samples. Levels of protease activity between 25 and 50% were noted in plasma from two D+ HUS patients. One D+HUS patient, who had clinical features of TTP, had a vWF-cleaving protease inhibitor producing a severe deficiency of vWF-cleaving protease.

Thus a deficiency of vWF-cleaving protease appears to be atypical in D+HUS. The detection of a vWF-cleaving protease inhibitor in one patient suggests it may be associated with infection such as E. coli 0157.
Diagnostic Accuracy of Triage Tests to Exclude Pulmonary Embolism
Authors: Lijmer Jeroen , Sanson Bernd-Jan , Büller Harry , Brandjes Dees , Mac Gillavry Melvin ,   the ANTELOPE-Study Group
Published: March 2018

We performed a study in 403 prospectively included patients with suspected pulmonary embolism to compare the accuracy of a combination of the SimpliRED D-dimer assay and an intuitive clinical probability estimate with either one alone. Based on a conjoint diagnostic reference standard, including ventilation-perfusion lung scintigraphy and pulmonary angiography, the prevalence of pulmonary embolism was 31%. We demonstrated a high sensitivity (98%, 95% CI 95-100) and negative predictive value (94%, 95% CI 79-99) for the combination of the two tests. These figures were more favorable than for either test alone. The specificity of the combination was lower (11%, 95% CI 9-12) and consequently the proportion of patients in whom further diagnostic tests would have been avoided was only 8%. We conclude that the combined use of the SimpliRED test and the clinical probability estimate attains a higher sensitivity than either test alone. However, there remains a risk of false negatives and the exclusion efficiency is limited.
Increased Hepatic Fibrinogen Bβ-gene Transcription Is not enough to Increase Plasma Fibrinogen Levels
Authors: Rezaee F. , Maas A. , Koopman J. , Verheijen J. H.
Published: March 2018

The fibrinogen Aα, Bβ, and γ polypeptides are encoded by three separate genes, which are arranged in the order γ-α-β. In order to study the biosynthesis of fibrinogen in vivo we generated a line of transgenic mice carrying extra copies of the fibrinogen β-gene. To clone the mouse fibrinogen Bβ-chain gene, a mouse 129 Sv/Ev genomic cosmid library was screened, using the mouse fibrinogen Aα-, Bγ-chain cDNA. A clone containing the complete fibrinogen Bβ-chain gene including approximately 11-kb of the natural promoter region was identified and subsequently microinjected into mice. Southern blot analysis identified a founder that carried additional copies of the fibrinogen Bβ-chain gene. Transgenic offspring of this founder were interbred and heterozygous and homozygous transgenic mice were obtained. Northern blot analysis demonstrated approximately a 3-fold increase in fibrinogen Bβ mRNA in heterozygous mice as compared to wild-type, whereas homozygous transgenic mice showed approximately a 9-fold increase. The levels of the Aα and γ mRNAs in transgenic homozygous mice were not changed as compared to those in wild-type mice. Fibrinogen levels in plasma were not significantly increased in transgenic mice as compared to wild-type mice.

These results indicate that: additional copies of the fibrinogen Bβ-chain gene lead to increased levels of the Bβ-chain mRNA in the liver; the increased levels of Bβ-chain mRNA in homozygous overexpression mice do not change the transcription levels of the two other fibrinogen mRNAs in vivo; the absence of an increased plasma fibrinogen level in the transgenic mice indicates that this level is not regulated solely by transcription of the Bβ-chain gene.
The Role of Factor XI in a Dilute Thromboplastin Assay of Extrinsic Coagulation Pathway
Authors: Xiong Shilong , He Xiaofan , Liu Fayi , Han Jianzhong , Li Juncheng , He Shilin , He Rong
Published: March 2018

Blood coagulation has been thought to be composed of both intrinsic and extrinsic pathways. Recent evidence strongly supports the critical role of the extrinsic pathway in the initiation of blood coagulation. This investigation established an assay that examines the role of FXI in the thromboplastin-initiated (extrinsic) coagulation based on this new concept. Plasma clotting times were measured at different concentrations of thromboplastin with activated FXII inhibited (FXIIa-inhibited Diluted Thromboplastin Time, FXIIaiDTT). Only at low concentrations of thromboplastin was FXIIaiDTT of FXI-deficient plasma significantly prolonged than that of normal plasma. Depletion of FXI from normal plasma prolonged its FXIIaiDTT and replenishment of FXI shortened it. FXIIaiDTTs of both FVIII-deficient and FIX-deficient plasma were remarkably prolonged, and addition of normal plasma dose-dependently shortened it. Furthermore, earlier α-thrombin inhibition was directly correlated with decreasing FXa generation. The amount of FXa production was: platelet-rich plasma > platelet-poor plasma > FXI-deficient plasma. Therefore, our findings from the FXIIaiDTT assays not only support the critical role of extrinsic pathway in blood coagulation initiation, but also demonstrate the importance of FXI as an amplifier of thrombin generation in thromboplastin-initiated coagulation.
Regulation of PAI-1 Concentration in Platelets by Systemic Administration of Antisense Oligonucleotides to Rats
Authors: Pawlowska Zofia , Chabielska Ewa , Kobylanska Anna , Maciaszek Anna , Swiatkowska Maria , Buczko Wlodzimierz , Stec Wojciech , Cierniewski Czeslaw
Published: March 2018

In this report we tested the effect of oligodeoxyribonucleotides antisense to PAI-1 mRNA administered into rats on PAI-1 concentration in platelets. Low doses of the antisense oligonucleotide (MPO-16R) reduced PAI-1 activity, both in rat blood plasma and platelet lysates by 20.5% and 28.7%, respectively. There was no change in platelet count after treatment with MPO-16R but treated platelets showed lower aggregability as compared with controls (37 ± 13% and 54 ± 12%, respectively). In an experimental model of rat arterial thrombosis, low doses of MPO-16R caused a significant delay in the occlusion time (31.8%). These data further support for the role of PAI-1 as a major determinant of arterial thrombolysis resistance and for the first time demonstrate the possibility of reduction of platelet PAI-1 concentration by antisense approach.
Prospective Randomised Open-label Comparison of Danaparoid with Dextran 70 in the Treatment of Heparin-induced Thrombocytopaenia with Thrombosis
Authors: Chong B. H. , Cade J. F. , Magnani H. , Manoharan A. , Oldmeadow M. , Arthur C. , Rickard K. , Gallo J. , Lloyd J. , Seshadri P. , Gallus A. S. , Chesterman C. N. ,   The Australian HIT Study Group
Published: March 2018

Aim: To compare clinical outcomes in a randomised comparison of treatment with danaparoid sodium (a heparinoid), or dextran 70, for heparin-induced thrombocytopaenia (HIT) plus thrombosis. Methods: Forty-two patients with recent thrombosis and a clinical diagnosis of probable HIT who presented at ten Australian hospitals during a study period of six and one half years were randomly assigned to open-label treatment with intravenous danaparoid or dextran 70, each combined with oral warfarin. Thirty-four patients (83%) had a positive platelet aggregation or 14C-serotonin release test for HIT antibody. Twenty-five received danaparoid as a bolus injection of 2400 anti-Xa units followed by 400 units per hour for 2 h, 300 units per hour for 2 h, and then 200 units per hour for five days. Seventeen received 1000 mL dextran 70 on day one and then 500 mL on days 2-5. Patients were reviewed daily for clinical evidence of thrombus progression or resolution, fresh thrombosis or embolism, bleeding or other complications. The primary trial endpoint was the proportion of thromboembolic events with complete clinical resolution by the time of discharge from hospital. Results: With danaparoid, there was complete clinical recovery from 56% of thromboembolic events compared to 14% after dextran 70 (Odds Ratio 10.53, 95% Confidence Interval 1.6–71.4; p = 0.02). Clinical recovery with danaparoid was complete or partial in 86% of thromboembolic events compared with 53% after dextran 70 (Odds Ratio 4.55, 95% Confidence Interval 1.2–16.7; p = 0.03). Overall clinical effectiveness of danaparoid was rated as high or moderate in 88% of patients compared with 47% for dextran 70 (p = 0.01). One patient given danaparoid died of thrombosis compared with three patients given dextran 70. The platelet count returned to normal after a mean of 6.7 days with danaparoid and 7.3 days with dextran 70. There was no major bleeding with either treatment. Conclusion: danaparoid plus warfarin treatment for HIT with thrombosis is effective, safe, and superior to dextran 70 plus warfarin.
Increased Concentrations of Soluble CD40 Ligand, RANTES and GRO-α in Preeclampsia – Possible Role of Platelet Activation
Authors: Solum Nils Olav , Ueland Thor , Videm Vibeke , Aukrust Pål , Mellembakken Jan Roar
Published: March 2018

Activated platelets may release inflammatory mediators that activate leukocytes and trigger inflammatory reactions in endothelial cells. We examined the concentrations of soluble CD40 ligand (sCD40L) and the chemokines RANTES and GRO-α in platelet-free plasma (PFP), and unstimulated and SFLLRN-stimulated platelet-rich plasma (PRP), as well as in platelet pellets before stimulation using enzyme immunoassays. Nineteen women with normal and twenty-one with preeclamptic pregnancies were studied, and several differences between these two groups of pregnancies were revealed (1). Women with preeclampsia had significantly increased concentrations of sCD40L and GRO-α in PFP (2). Platelets from these patients spontaneously released larger quantities of CD40L and RANTES ex vivo (3). When further activated ex vivo by SFLLRN, platelets from preeclamptic women released lower amounts per platelet of CD40L, RANTES and GRO-α (4). The platelet pellets in preeclamptic women contained decreased amounts of CD40L, RANTES and GRO-α per platelet. Our findings suggest enhanced platelet activation in vivo during preeclampsia resulting in increased release of inflammatory mediators, possibly contributing to inflammation, leukocyte activation and endothelial dysfunction in this disorder.
A Novel Transgenic Mouse Model of Hyperfibrinogenemia
Authors: Gulledge Alyssa , Rezaee Farhad , Verheijen Jan , Lord Susan
Published: March 2018

Hyperfibrinogenemia is a risk predictor in several diseases, including cardiovascular disease. Nevertheless, it remains unknown whether elevated fibrinogen has an etiologic role in or is a reflection of disease pathogenesis, or both. To examine this question, we generated a mouse model of hyperfibrinogenemia. We isolated the mouse fibrinogen locus, containing the three fibrinogen genes, in a single P1 clone. This ~ 100 kb clone was injected into C57Bl/6J zygotes. Three transgenic lines were identified, two with elevated fibrinogen, 1.4- and 1.7-fold relative to normal. We characterized the line with the higher level. Northern blots of total RNA showed transgene expression was liver specific, and the message levels were 2- to 3-fold enhanced. Fibrinogen in transgenic mice was normal in both immunologic and clotting assays. Our data indicate that over-expression of all three fibrinogen genes is necessary to achieve hyperfibrinogenemia. We saw no increase in mortality or morbidity, no gross abnormalities in the organs, and no histologic differences in lung, liver, spleen or kidney, in transgenic mice relative to normal littermates. We conclude that elevated fibrinogen did not cause disease in mice. We anticipate that breeding these mice to other mouse models of disease will demonstrate whether hyper-fibrinogenemia has a role in the initiation or progression of symptomatic disease.
Anticardiolipin Antibody Assay: a Methodological Analysis for a better Consensus in Routine Determinations
Authors: Allegri Flavio , Sanmarco Marielle , Cinquini Massimo , Taglietti Marco , Balestrieri Genesio , Koike Takao , Ichikawa Kenji , Meroni Pierluigi , Boffa Marie Claire , Tincani Angela
Published: March 2018

Despite the widely recognized practical importance of anticardiolipin (aCL) ELISA, the reliability of this test has been recently discussed. In order to investigate this area on European scale, we sent to 30 experienced centers a questionnaire focusing on the diagnostic procedures applied to patients with antiphospholipid syndrome (APS) and on the detailed protocols used to perform aCL. Anticardiolipin ELISA was found to be the most frequently performed test in patients with suspected APS, but significant difference was shown among the various protocols. The cross-laboratory multiple examination of ten serum samples evaluated independently by the 24 centers pointed out the difficulty in getting comparable results. Therefore a “consensus” protocol was derived from the aCL methods giving the best performance. The materials and reagents necessary to perform the “consensus” method, including, as putative standards, one IgG and one IgM monoclonal antibody (HCAL and EY2C9) were distributed to 19 Centers. The results of one IgG and one IgM aCL high positive sera measured in serial dilutions were compared. A progressive decrease in the variability of the values obtained for a given sample appeared evident when all the laboratories used the same standard, in their own in-house ELISA and even more in the “consensus” ELISA.

Our data show that aCL ELISA standardization is necessary in order to obtain comparable results in different laboratories.
β2-glycoprotein I-dependent Anticardiolipin Antibodies Preferentially Bind the Amino Terminal Domain of β2-glycoprotein I
Authors: McNeeley Patricia , Dlott Jeffrey , Furie Richard , Jack Richard , Triplett Douglas , Victoria Edward , Ortel Thomas , Linnik Matthew
Published: March 2018

Many of the autoantibodies in antiphospholipid syndrome (APS) are directed against β2-glycoprotein I (β2-GPI). Recent studies from our laboratories have indicated that the immunodominant binding epitope(s) for high titer, affinity purified antibodies from 11 APS patients are localized to the amino terminal domain (domain 1) of β2-GPI. The present study employed surface plasmon resonance to localize the immunodominant domain in serum samples from a large cohort of patients with GPL values ranging from 21 to 230 units (n = 106 patients). Eighty-eight percent of patients showed ≥ threefold selectivity for β2-GPI containing domain 1 relative to the domain deletion mutant that lacked domain 1. The domain 1 binding activity in patient serum was abolished by removing the IgG fraction from the serum and the binding activity could be fully reconstituted with the IgG fraction. Thus, analysis of serum samples from a large cohort of APS patients indicates that the immunodominant binding epitope(s) for anti- 2 antibodies are localized to the amino terminal domain of β2-GPI.