Calibrated automated thrombography demonstrates hypercoagulability in patients with idiopathic pulmonary arterial hypertension

Introduction

Pathogenesis of idiopathic pulmonary arterial hypertension (iPAH) includes endothelial dysfunction and in situ thrombosis. A hypercoagulable state has also been postulated but never demonstrated. Our objective was to determine whether patients with iPAH had a hypercoagulable state using calibrated automated thrombography (CAT), a new tool to phenotype coagulation in vitro.

Patients and methods

16 patients with iPAH and 29 controls were studied. In vitro platelet dependent coagulation phenotyping by CAT monitored the activity of thrombin generation over time. Plasma levels of soluble thrombomodulin, tissue factor pathway inhibitor (TFPI) and von Willebrand factor (VWF) were measured as endothelial biomarkers.

Results

Endogenous thrombin potential (ETP) in the absence of activated protein C (APC) tended to be increased in patients compared to controls (1769 versus 1656 nM.min; p = 0.053). ETP was higher in the presence of APC 25 nM (ETP-APC) in patients (781 versus 494 nM.min; p = 0.005). Five patients had ETP-APC higher than the 95th centile of controls. Other CAT parameters (lag time, peak thrombin and time to peak) were all consistent with some degree of hypercoagulability in patients. Regarding endothelial plasma biomarkers sTM was lower (28.4 versus 40.6 μg/l, p = 0.0108) in patients; TFPI antigen and activity (respectively: 14.3 versus 10.5 μg/l, p = 0.0167; 1.155 versus 1.070, p = 0.0021) and VWF (1300 versus 976%, p = 0.0108) were higher in patients.

Conclusion

We have demonstrated that at least some patients with iPAH have a hypercoagulable phenotype.     

Antithrombotic Activity of the Novel Oral Anticoagulant, Tecarfarin [Sodium 3-[4-((1,1,1,3,3,3-hexafluoro-2-methylpropan-2-yloxy) carbonyl) benzyl]-2-oxo-2H-chromen-4-olate] in Animal Models

The antithrombotic activity of tecarfarin, a novel orally active vitamin K epoxide reductase inhibitor, was assessed in canine and rabbit thrombosis models. In dogs, once-daily oral doses of 0.5 mg/kg tecarfarin selectively reduced the levels of the vitamin K-dependent coagulation factors (factors II, VII, IX, and X) and prolonged the prothrombin time (PT). A 4 to 7 day course of oral tecarfarin (0.05 - 0.5 mg/kg) prolonged the PT by 3 to 5-fold and reduced thrombus formation in arterial and venous segments subjected to a combination of electrical injury and flow-limiting constriction. To compare the effects of tecarfarin with those of warfarin, rabbits were given once-daily oral doses of 1 mg/kg tecarfarin, 1.5 mg/kg warfarin, or saline for 2 days. After verifying increases in the PT with tecarfarin and warfarin, blood loss from standardized ear incisions was measured to assess hemorrhagic potential. Then, after intravenous injection of ¹²⁵I-labeled rabbit fibrinogen, thrombosis was induced in an isolated jugular vein segment by a combination of balloon catheter-induced endothelial denudation and venous occlusion. Compared with the saline control, both tecarfarin and warfarin prolonged the PT, increased blood loss from the ear incisions, and attenuated thrombus formation. Thus, like warfarin, tecarfarin attenuates venous and arterial thrombus formation in animal models by reducing the levels of the vitamin K-dependent coagulation factors.     

Single-nucleotide polymorphism in the promoter region of the osteopontin gene at nucleotide -443 as a marker predicting the efficacy of pegylated interferon/ribavirin-therapy in Egyptians patients with chronic hepatitis C

Osteopontin (OPN) is an extracellular matrix glycophosphoprotein produced by several types of cells including the immune system. The present study examined the possibility that single-nucleotide polymorphisms (SNP) in the promoter region of the OPN at nt -443 is a marker predicting the therapeutic efficacy of pegylated interferon (peg-IFN-α2b)-ribavirin combination therapy in Egyptian patients with chronic hepatitis C. Blood was collected from 95 patients with chronic hepatitis C who had received peg-IFN-α2b-ribavirin combination therapy and 100 age and sex matched controls. SNP in OPN at nucleotide (nt) -443 and its serum protein level were analyzed. Sustained virological response (SVR) was higher in patients with T/T at nt -443 than in those with C/C or C/T. A univariate logistic regression analysis showed that fibrosis grade, serum OPN protein level and T/T homozygotes of SNP at -443 were significant predictors for response. Receiver operating characteristics (ROC) analysis revealed the diagnostic and prognostic efficacy of serum OPN. It can be concluded that SNP in the promoter region of OPN at nt -443 and serum OPN protein level are predictors of response to the efficacy of peg-IFN-α2b-ribavirin therapy in Egyptian patients with chronic hepatitis C.     

Safety assessment of a proprietary preparation of a novel Probiotic, Bacillus coagulans, as a food ingredient

It has been demonstrated that some strains of Bacillus coagulans can survive extremes of heat, acidity of the stomach, and bile acids, to which commonly consumed probiotics are susceptible. A toxicological safety assessment was performed on a proprietary preparation of B. coagulans – GanedenBC^30™ – a novel probiotic. Seven toxicologic studies were conducted and included: in vitro bacterial reverse mutation assay; in vitro chromosomal aberration assay; micronucleus assay in mice; acute and 90 day subchronic repeated oral toxicity studies were conducted in Wistar Crl:(WI) BR rats; acute eye and skin irritation studies were conducted in rabbits.     

Prediction of the therapeutic index of marketed anti-coagulants and anti-platelet agents by guinea pig models of thrombosis and hemostasis

Introduction

Animal models of thrombosis and hemostasis are critical for target validation in pharmaceutical research. Guinea pig haemostatic mechanisms, such as the platelet thrombin receptor repertoire, resemble those of humans. Measuring the performance characteristics of marketed antithrombotic drugs in guinea pig models is a key to predicting therapeutic indices of new agents. The goal of the current study was to benchmark representative marketed drugs in thrombosis and hemostasis models in guinea pigs.

Methods

Effects of the cyclooxygenase inhibitor, aspirin, the P2Y₁₂ antagonist, clopidogrel, the glycoprotein IIb/IIIa inhibitor, tirofiban, and the direct thrombin inhibitors, argatroban and hirudin, were evaluated in this study. Antithrombotic agents were tested in FeCl₃-induced carotid artery thrombosis and arterio-venous shunt thrombosis models. Haemostatic effects of drugs were evaluated in cuticle and renal bleeding models. Ex vivo measurements of platelet function and coagulation inhibition were performed to benchmark preclinical doses of each agent to those used clinically.

Results

The overall rank-order of potency in thrombosis models based on per cent of vessels occluded, average carotid blood flow, and thrombus weight was aspirin = argatroban = tirofiban < hirudin = clopidogrel. In bleeding models, the rank order was: aspirin < clopidogrel = argatroban = tirofiban < hirudin.

Conclusion

This characterization of representative drugs from two important classes of anti-coagulant and anti-platelet agents in efficacy and bleeding models in guinea pigs provides a reference point for evaluation of new antithrombotic agents.     

Female specific anterior cingulate abnormality and its association with empathic disability in schizophrenia

Evidence suggests that impairments of empathy are present in schizophrenia and that such deficits lead to social dysfunction. However, the relationship between brain morphological abnormalities of the disorder and empathic disabilities has not been fully investigated. As the anterior cingulate cortex (ACC) is one of the critical structures for empathy processing, the pathology of this structure might be a major source of social dysfunction, including interpersonal miscommunication in schizophrenia. In addition, as recent studies suggest that different facets of empathic ability depend on different subdivisions of the ACC, pathology of each subdivision would affect the empathic disability of schizophrenia differentially. Structural MRI data were acquired at 3.0 T from 24 schizophrenic patients and 20 healthy participants, and the volumes of ventral and dorsal ACC were measured and compared between the groups. Subjects' empathic abilities were evaluated using a multidimensional questionnaire, the Interpersonal Reactivity Index (IRI). The relationships of structural abnormalities with empathic disabilities were investigated, by correlating ACC subdivisional volumes with each IRI subscale score. Female schizophrenic patients exhibited volume reductions in the ventral ACC bilaterally and in the left dorsal ACC compared with healthy subjects. Schizophrenic patients performed poorly on fantasy and personal distress subscales of the IRI. Furthermore, volumes of the left dorsal ACC were inversely correlated with personal distress subscale scores within female patients with schizophrenia. These results suggest that pathology of specific ACC subdivisions would have an impact on specific empathic disabilities in schizophrenia, with potential gender specificity.     

High-resolution HLA haplotype frequencies of stem cell donors in Germany with foreign parentage: How can they be used to improve unrelated donor searches?

In hematopoietic stem cell transplantation, human leukocyte antigens (HLA), usually HLA loci A, B, C, DRB1 and DQB1, are required to check histocompatibility between a potential donor and the recipient suffering from a malignant or non-malignant blood disease. As databases of potential unrelated donors are very heterogeneous with respect to typing resolution and number of typed loci, donor registries make use of haplotype frequency-based algorithms to provide matching probabilities for each potentially matching recipient/donor pair. However, it is well known that HLA allele and haplotype frequencies differ significantly between populations. We estimated high-resolution HLA-A, -B, -C, -DRB1 haplotype and allele frequencies of donors within DKMS German Bone Marrow Donor Center with parentage from 17 different countries: Turkey, Poland, Italy, Russian Federation, Croatia, Greece, Austria, Kazakhstan, France, The Netherlands, Republic of China, Romania, Portugal, USA, Spain, United Kingdom and Bosnia and Herzegovina. 5-locus haplotypes including HLA-DQB1 are presented for Turkey, Poland, Italy and Russian Federation. We calculated linkage disequilibria for each sample. Genetic distances between included countries could be shown to reflect geography. We further demonstrate how genetic differences between populations are reflected in matching probabilities of recipient/donor pairs and how they influence the search for unrelated donors as well as strategic donor center typings.     

不同检测系统凝血三项测定结果的可比性研究

目的:探讨不同血凝检测系统凝血三项(凝血酶原时间,PT;活化部分凝血酶原时间,APTT;纤维蛋白原,Fg)的检测结果是否具有可比性。方法:分别采用不同水平质控物和40例不同浓度的患者新鲜血浆,在3个不同检测系统(ACL-200、ACL-3000、CA-1500)测定凝血三项。结果:不同浓度患者新鲜血浆凝血三项测定结果总体均值差异均有显著性(P<0.01)。以CA-1500作目标系统对其它系统作临床可接受性能评价,ACL-200、ACL-3000系统的PT、APTT临床部分接受,Fg临床均接受。结论:3个检测系统凝血三项测定结果临床接受性能评价除Fg外均存在不可比性,需采取整改措施。