Increased venous versus arterial thrombosis in the Factor V Leiden mouse

BACKGROUND: Deep vein thrombosis (DVT) occurs with high prevalence in association with the Factor V Leiden (R506Q) mutation, whereas most evidence suggests no correlation with clinical arterial thrombosis. OBJECTIVE: This study compared arterial to venous thrombosis in the mutationally analogous Factor V Leiden mouse. METHODS: Three separate vascular thrombosis models were evaluated in Fv(+/+) (wild-type), Fv(Q/+) (heterozygous) and Fv(Q/Q) (homozygous) Factor V Leiden mice. RESULTS: In a FeCl(3)-induced arterial thrombosis model, no statistical differences among the three genotypes were found in the time to thrombotic occlusion. In contrast, Fv(Q/+) and Fv(Q/Q) mice demonstrated larger femoral vein thrombi at 30 and 60 min compared to wild-types, with Fv(Q/Q) mice having statistically larger thrombi than both wild-type and Fv(Q/+) mice at 10 and 60 min and 24 h (p<0.05). In a model of thrombotic occlusion following arterial and venous anastomotic repair, both Fv(Q/+) and Fv(Q/Q) mice had higher rates of venous thrombosis than wild-types, but only Fv(Q/Q) homozygotes showed a statistically greater arterial occlusion rate than wild-types. CONCLUSION: The Factor V Leiden mouse demonstrated a greater propensity for venous vs. arterial thrombosis, paralleling clinical epidemiologic findings and supporting its use for research on deep vein thrombosis.     

Prothrombotic effect of Rofecoxib in a murine venous thrombosis model

The potential prothrombotic effect of the cyclooxygenase-2 (COX-2) inhibitor Rofecoxib (Vioxx) was investigated using murine thrombosis models. In a jugular vein thrombosis model (photochemically induced injury) in lean wild-type mice, Rofecoxib treatment for 4 weeks induced a mild prothrombotic tendency, as indicated by a shorter occlusion time as compared to placebo (median of 12 min versus 36 min; p<0.05). Thrombus size was somewhat, but not significantly, enhanced after Rofecoxib treatment. In a femoral artery thrombosis model (FeCl(3) induced injury) Rofecoxib did not cause an enhanced thrombotic tendency in mice with nutritionally induced or genetically determined (ob/ob) obesity. The occlusion time was comparable for obese wild-type mice with (8.8+/-0.7 min) or without (7.8+/-2.1 min) Rofecoxib treatment, as well as for ob/ob mice (8.5+/-0.7 min versus 6.8+/-3.0 min). Thus, an enhanced prothrombotic effect of Rofecoxib was detected when using a venous thrombosis model in lean mice, but not when using an arterial thrombosis model in obese mice.     

G4120, an Arg-Gly-Asp containing pentapeptide, enhances arterial eversion graft recanalization with recombinant tissue-type plasminogen activator in dogs.

The effects of G4120, a cyclic Arg-Gly-Asp (RGD) containing peptide which inhibits fibrinogen binding to the platelet receptor GPIIb/IIIa, on thrombolysis with recombinant tissue-type plasminogen activator (rt-PA) were investigated in a combined arterial and venous thrombosis model in heparinized dogs. The arterial thrombus model consisted of a 3 cm everted (inside-out) carotid arterial segment inserted into a transsected femoral artery which occludes within 30 min with platelet-rich material and which is resistant to recanalization with 0.5 mg/kg rt-PA. The venous thrombus was a 125I-fibrin labeled whole blood clot produced in the contralateral femoral vein. In 5 dogs given an intravenous bolus of 0.05 mg/kg G4120 followed by a continuous infusion of 0.05 mg/kg per hour for 3 h (group I), arterial occlusion persisted throughout a 4 h observation period and was still present at 24 h in all dogs; the extent of venous clot lysis after 120 min was 27 +/- 7%. In 5 dogs given the same infusion of G4120 in combination with 0.5 mg/kg rt-PA over 60 min, recanalization of the arterial graft occurred in all dogs, within 13 +/- 2 min and persisted throughout the observation period of 4 h (p = 0.01 versus G4120 or rt-PA alone); at 24 h, however, all grafts were occluded. Venous clot lysis in this group was 75 +/- 8% (p = 0.002 versus G4120 alone and p = NS versus rt-PA alone). Pathologic analysis revealed platelet-rich or mixed thrombus with platelet-rich and erythrocyte-rich zones.(ABSTRACT TRUNCATED AT 250 WORDS)     

Extension of cerebral hypoperfusion and ischaemic pathology beyond MCA territory after intraluminal filament occlusion in C57Bl/6J mice

Rodent models of focal cerebral ischaemia are critical for understanding pathophysiological concepts in human stroke. The availability of genetically modified mice has prompted the adaptation of the intraluminal filament occlusion model of focal ischaemia for use in mice. In the present study, we investigated the effects of increasing duration of intraluminal occlusion on the extent and distribution of ischaemic pathology and local cerebral blood flow (LCBF) in C57Bl/6J mice, the most common background mouse strain. Volumetric assessment of ischaemic damage was performed after 15, 30 or 60 min occlusion followed by 24 h reperfusion. LCBF was measured after 15 and 60 min occlusion using quantitative 14C-iodoantipyrine autoradiography. The extent and distribution of ischaemic damage was highly sensitive to increasing occlusion duration. Recruitment of tissue outside MCA territory produced a steep increase in the volume of damage with increasing occlusion duration: 15 min (9+/-2 mm3); 30 min (56+/-6 mm3); 60 min (69+/-2 mm3). Significant increases in the severity of cerebral hypoperfusion were observed after 60 min compared to 15 min occlusion within and outside MCA territory, e.g. caudate nucleus (9+/-6 ml per 100 g per min at 60 min vs. 33 ml per 100 g per min at 15 min) and hippocampus (16+/-14 ml per 100 g per min at 60 min vs. 61+/-16 ml per 100 g per min at 15 min). MABP remained stable for 25 min after occlusion onset and declined thereafter. The integrity of the circle of Willis was examined by carbon black perfusion of the vasculature. A complete circle of Willis was present in only one of 10 mice. These results demonstrate that intraluminal filament occlusion in C57Bl/6J mice leads to an occlusion duration-dependent increase in severity of cerebral hypoperfusion and extension of ischaemic pathology beyond MCA territory.     

Altered fibrin clot properties are associated with residual vein obstruction: Effects of lipoprotein(a) and apolipoprotein(a) isoform

We tested the hypothesis that fibrin structure/function is unfavorably altered in patients with residual vein obstruction (RVO). Ex vivo plasma fibrin clot permeability, turbidimetry and efficiency of fibrinolysis were investigated in 86 patients with RVO following first-ever proximal deep vein thrombosis (DVT), and 86 DVT controls with no evidence of RVO. The RVO patients had 14.1% lower clot permeability (p = 0.011), 11.3% longer lysis time (p = 0.009) and 7.8% lower rate of D-dimer release from fibrin clots than controls (p = 0.022), with no differences related to thrombophilia, and duration or stability of anticoagulant therapy. RVO patients showed higher lipoprotein(a) (p = 0.014) with overrepresentation of smaller apolipoprotein(a) isoforms, corresponding approximately to 21 or fewer kringle IV type 2 repeats (p = 0.09), both associated with alterations to plasma fibrin clot characteristics. In conclusion, prothrombotic plasma fibrin clot phenotype related to elevated lipoprotein(a) with smaller apolipoprotein(a) isoforms might represent a novel risk factor for RVO.     

Differential role of components of the fibrinolytic system in the formation and removal of thrombus induced by endothelial injury

The role of fibrinolytic system components in thrombus formation and removal in vivo was investigated in groups of six mice deficient in urokinase-type plasminogen activator (u-PA), tissue-type plasminogen activator (t-PA), or plasminogen activator inhibitor-1 (PAI-1) (u-PA-/-, t-PA-/- or PAI-1-/-, respectively) or of their wild type controls (u-PA+/+, t-PA+/+ or PAI-1+/+). Thrombus was induced in the murine carotid artery by endothelial injury using the photochemical reaction between rose bengal and green light (540 nm). Blood flow was continuously monitored for 90 min on day 0 and for 20 min on days 1, 2 and 3. The times to occlusion after the initiation of endothelial injury in u-PA+/+, t-PA+/+ or PAI-1+/+ mice were 9.4+/-1.3, 9.8+/-1.1 or 9.7+/-1.6 min, respectively. u-PA-/- and t-PA-/- mice were indistinguishable from controls, whereas that of PAI-1-/- mice were significantly prolonged (1 8.4+/-3.7 min). Occlusion persisted for the initial 90 min observation period in 10 of 18 wild type mice and was followed by cyclic reflow and reocclusion in the remaining 8 mice. At day 1, persistent occlusion was observed in 1 wild type mouse, 8 mice had cyclic reflow and reocclusion and 9 mice had persistent reflow. At day 2, all injured arteries had persistent reflow. Persistent occlusion for 90 min on day 0 was observed in 3 u-PA-/-, in all t-PA-/- mice at day 1 and in 2 of the t-PA-/-mice at day 2 (p <0.01 versus wild type mice). Persistent patency was observed in all PAI-1-/- mice at day 1 and in 5 of the 6 u-PA-/- mice at day 2 (both p <0.05 versus wild type mice). In conclusion, t-PA increases the rate of clot lysis after endothelial injury, PAI-1 reduces the time to occlusion and delays clot lysis, whereas u-PA has little effect on thrombus formation and spontaneous lysis.     

Residual venous obstruction in patients with a single episode of deep vein thrombosis and in patients with recurrent deep vein thrombosis

Residual venous obstruction (RVO) in patients with previous deep vein thrombosis (DVT) of the lower limbs has been suggested as an independent risk factor for recurrent venous thromboembolism (VTE). RVO could be a marker of a persistent prothrombotic state. We have compared the rate of RVO in patients with DVT and a personal history of at least one previous episode of VTE to the rate of RVO among patients with a first episode of DVT. All patients underwent compression ultrasonography (CUS) of the lower limbs 1 year after index DVT. RVO was arbitrarily defined as a thrombus occupying, at maximal compressibility, more than 20% of the vein area in the absence of compression. 50 consecutive patients with recurrent DVT and 50 age and sex-matched patients with a single episode of DVT were enrolled. The index event was idiopathic in 62% of patients with recurrent DVT and in 60% of patients with a single episode. In 74% of patients with recurrent DVT the index event occurred in either the contralateral leg or in a different segment of the ipsilateral leg. RVO was detected in 50% of patients with a single episode of DVT and in 88% of patients with recurrent DVT (p<0.00001). The prevalence of RVO is significantly higher in patients with recurrent DVT than in patients with a single episode. This finding supports the importance of RVO as a potential marker of a persistent prothrombotic state.     

Hyperhomocysteinemia and other newly recognized inherited coagulation disorders (factor V Leiden and prothrombin gene mutation) in patients with idiopathic cerebral vein thrombosis

BACKGROUND: Idiopathic cerebral vein thrombosis (iCVT) represents approximately 30% of the cases of cerebral vein thrombosis (CVT). New, inherited - factor V Leiden (FVL) and prothrombin gene mutation (PTHRA20210) - and inherited/acquired - hyperhomocysteinemia (HHcy) - prothrombotic conditions have been detected recently. METHODS: We assessed fasting plasma homocysteine (Hcy) levels and main Hcy determinants, FVL and PTHRA(20210) in 30 patients with documented iCVT and 40 age- and sex-matched healthy subjects. RESULTS: A strong and significant association of PTHRA(20210) [30% (9/30) vs. 2.5% (1/40) iCVT vs. controls, respectively, p = 0.001; OR = 16.174, p = 0.002] and HHcy [13/30 (43.3%) vs. 4/40 (10%) iCVT vs. controls, respectively; p = 0.002, OR = 6.88, p = 0.002] with iCVT was found. CONCLUSIONS: PTHRA(20210) and HHcy should be considered when screening for thrombophilia and should be assessed in patients with a family or personal history of CVT.     

Ovarian vein thrombosis: incidence of recurrent venous thromboembolism and survival

For patients with ovarian vein thrombosis (OVT), neither the rate of recurrence nor the expected survival are well established. Clarification of these natural history data would aid in defining the optimal management. We studied all female patients with OVT seen at the Mayo Clinic between 1990 and 2006. Survival, recurrent venous thrombosis rates, and prothrombotic factors were compared to a randomly selected group of 114 female patients with lower extremity venous thrombosis (DVT). Patients with OVT (n = 35; mean age 44.8 +/- 17.9 years) were significantly more likely to be under hormonal stimulation (48%), have an underlying malignancy (34%), experienced recent pelvic infection (23%) or undergone recent surgery (20%), compared to DVT patients. During a mean follow-up period of 34.6 +/- 44.3 months, three patients suffered three recurrent venous thrombi (event rate: three per 100 patient years of follow-up). This recurrence rate was comparable to patients with lower extremity DVT (2.2 per 100 patient years). Recurrent thrombosis involved the contralateral ovarian vein, left renal vein, and inferior vena cava. The five-year mortality rate for OVT patients was 43% compared to 20% for DVT patients (p = 0.08). All OVT deaths were cancer related. Survival was greater in OVT patients without cancer compared to those with active cancer (p < 0.0001). In conclusion, venous thromboembolism recurrence rates are low and comparable to lower extremity DVT. Therefore general treatment guidelines for lower extremity DVT may be applicable. Poor survival rates in OVT are principally governed by the presence of malignancy.     

Few predictors of massive deep vein thrombosis

Factors that predispose to thrombus propagation from the femoropopliteal veins to the pelvic veins are poorly understood. Our goal was to determine whether there are characteristics that identify patients with massive deep vein thrombosis (DVT). We compared the 122 (2.5%) patients presenting with massive DVT (pelvic plus lower-extremity DVT) to the 4,674 (97.5%) patients with isolated lower-extremity DVT from a prospective United States multicenter DVT registry. Patients with massive DVT were younger (59.4+/-18.9 years vs. 64.3+/-16.8 years; p<0.01), less likely to have hypertension (40% vs. 51%; p=0.02), and more likely to smoke (21% vs. 13%; p=0.02) and have ongoing radiation therapy (7% vs. 3%; p=0.02). The massive DVT group more commonly presented with extremity edema (80% vs. 69%; p<0.01) and erythema (21% vs. 12%; p<0.01) than the isolated lower-extremity DVT group. However, after multivariable logistic regression analysis, extremity erythema (adjusted odds ratio 1.86; 95% CI 1.13-3.04) was the only independent sequela of massive DVT and younger age (adjusted odds ratio 1.17 per decreasing decade of age; 95% confidence interval: 1.02-1.34) was the only independent predictor of massive DVT. Thrombus propagation from the femoropopliteal system cannot be reliably predicted using demographic or clinical characteristics.     

Lipopolysaccharide augments venous and arterial thrombosis in the mouse

BACKGROUND: Animal models of diseases are essential for therapeutic target validation, drug discovery and development. Increasing evidence has demonstrated the importance of inflammation in thrombosis. Here, murine models of vena cava thrombosis and carotid arterial thrombosis augmented by lipopolysaccharide (LPS) were established and characterized to study the association between inflammation and thrombosis. MATERIALS AND METHODS: Murine (C57BL/6 mice) models of ferric chloride (FeCl(3))-induced carotid arterial and vena cava thrombosis were established. Thrombus formation was measured indirectly by Doppler blood flow (i.e., clot functional interference with blood flow) in the arterial thrombosis model and directly by protein content of the clot in the venous thrombosis model. An optimal concentration of FeCl(3) was defined to induce thrombus formation and used to study the effects of LPS (i.e., a well-known inflammatory stimulus under these conditions). Real-time polymerase chain reaction (PCR) was used to examine the effect of LPS on TNFalpha and IL-1beta mRNA expression in thrombus formation. RESULTS: Dose-dependent analysis demonstrated that 2 mg/kg, i.p., LPS provided a maximal prothrombotic effect in 2.5% ferric chloride-induced vena cava thrombosis, with a 60% increase in thrombus size (n=8, p<0.05) compared to vehicle treatment. In contrast, 2 mg/kg LPS had no significant effect on thrombus formation in a more severe, 3.5% FeCl(3)-induced vena cava thrombosis. A similar prothrombotic effect was observed for LPS in 2.5% FeCl(3)-induced carotid arterial thrombosis model. Treatment of 2 mg/kg LPS significantly augmented arterial thrombosis immediately (between 5-30 minutes) following FeCl(3) injury as assessed by change of Doppler blood flow (n=8, p<0.05). Real-time PCR demonstrated significant induction of TNFalpha and IL-1beta mRNA expression in the thrombus formation in the vessels in response to LPS challenge. CONCLUSION: These data demonstrate that LPS augments thrombus formation in acute vascular injury and that LPS-augmented thrombosis might be a useful tool to study the relationship between inflammation and thrombosis.     

Thrombolytic and pharmacokinetic properties of human tissue-type plasminogen activator variants, obtained by deletion and/or duplication of structural/functional domains, in a hamster pulmonary embolism model

A pulmonary embolism model in hamsters was used for the quantitative evaluation of the thrombolytic and pharmacokinetic properties of variants of tissue-type plasminogen activator (t-PA). A 25 microliters 125I-fibrin labeled human plasma clot was made in vitro and injected into the jugular vein of heparinized hamsters. The extent of thrombolysis within 90 min was determined as the difference between the radioactivity injected in the jugular vein and that recovered in the heart and lungs. Recombinant t-PA (home-made rt-PA or Activase) infused intravenously over 60 min caused dose-dependent progressive thrombolysis. The results of thrombolytic potency (clot lysis in percent versus dose administered in mg/kg) and of specific thrombolytic activity (clot lysis in percent versus steady state plasma level in microgram/ml) were fitted with an exponentially transformed sigmoidal function y = 100 c/(1 + e-a(ax-eh] and the maximal percent lysis (c), the dose or plasma level at which maximal rate of lysis is achieved (b) and the maximal rate of lysis (z = 1/4 ac.eb) were determined. With rt-PA, these parameters were c = 72 +/- 6% (mean +/- SEM), b = 0.19 +/- 0.08 mg/kg, z = 68 +/- 25% lysis per mg/kg, with corresponding values of 87 +/- 5%, 0.07 +/- 0.03 mg/kg and 150 +/- 38% lysis per mg/kg for Activase (p = NS). Deletion of the finger and growth factor domains in rt-PA (rt-PA-delta FE) was not associated with marked alteration of the thrombolytic potency (c = 90 +/- 30%, b = 0.34 +/- 0.35 mg/kg, and z = 54 +/- 14% per mg/kg), but was associated with a significant reduction of the specific thrombolytic activity.(ABSTRACT TRUNCATED AT 250 WORDS)     

D-dimer as a risk factor for deep vein thrombosis: the Leiden Thrombophilia Study

We studied the association of D-dimer with the risk of deep vein thrombosis (DVT). D-dimer was measured in 474 patients more than 6 months after diagnosis of a first DVT and in 474 age- and sex-matched controls. For D-dimer above the 70th percentile (130.5 ng/ml), the odds ratio (OR) for DVT was 2.2 (95% CI, 1.6-2.9). The association was unchanged with adjustment for other risk factors. Excluding participants with Factor V Leiden, prothrombin 20210A, or factors VIIIc or IX above the 90th percentile, the OR was 1.6 (95% CI, 1.1-2.3). The risks of DVT with the joint presence of high D-dimer and either factor V Leiden or prothrombin 20210A were increased 12.4-fold (95% CI 5.6-27.7) and 7.2-fold (95% CI 2.1-25.1), respectively. Higher D-dimer concentration was associated with the risk of DVT, and was supra-additive to the risks associated with factor V Leiden and the prothrombin 20210A variant. Persistence of this association in the absence of other hemostatic risk factors for DVT suggests that high D-dimer may be related to other, as yet unknown, risk factors for venous thrombosis. Confirmation of these findings is desirable.     

Postoperative changes in the plasmatic levels of tissue-type plasminogen activator and its fast-acting inhibitor--relationship to deep vein thrombosis and influence of prophylaxis

Fibrinogen, euglobulin lysis time (ELT), tissue-type plasminogen activator (t-PA) antigen, plasminogen activator inhibitor activity (PA-inhibitor) and alpha 2-antiplasmin (alpha 2-AP) were measured pre- and postoperatively in 60 patients undergoing total hip replacement. Reduced fibrinolytic activity as assessed by the prolongation of euglobulin lysis time, decrease of t-PA and increase of PA-inhibitor and alpha 2-AP could be demonstrated. These changes did not correlate with the postoperative deep vein thrombosis (DVT) diagnosed with the 125I-fibrinogen test. However, preoperative PA-inhibitor activity was significantly higher in patients with postoperative DVT (p less than 0.01). The prophylactic treatment with aspirin (20 patients) and with heparin plus dihydroergotamine (20 patients) induced significant changes in some of those parameters. This study shows that the decrease of t-PA and the increase of PA-inhibitor may contribute to the reduced postoperative fibrinolytic activity after total hip replacement. PA-inhibitor level might be a useful marker in evaluating the risk of developing DVT in patients undergoing total hip replacement.     

Haplotype of thrombomodulin gene associated with plasma thrombomodulin level and deep vein thrombosis in the Japanese population

INTRODUCTION: Thrombomodulin (TM) is an essential cofactor in protein C activation by thrombin. Here, we evaluated the contribution of genetic variations in the TM gene to soluble TM (sTM) level and deep vein thrombosis (DVT) in Japanese. PATIENTS AND METHODS: We sequenced the TM putative promoter, exon, and 3'-untranslated region in DVT patients (n=118). Among 17 genetic variations we identified, two missense mutations (R385K, D468Y) and three common single nucleotide polymorphisms (-202G>A, 2487A>T, 2729A>C) were genotyped in a general population of 2247 subjects (1032 men and 1215 women) whose sTM levels were measured. We then compared the frequency of these mutations in DVT patients with that in the age, body mass index-adjusted population-based controls. RESULTS: We identified one neutral mutation (H381) and three missense mutations (R385K; n=2, A455V; n=53 heterozygous, n=14 homozygous, D468Y; n=2) of TM in the DVT patients. Age-adjusted mean values of sTM were lower in C-allele carriers of 2729A>C than in noncarriers in the Japanese general population (women: 16.7+/-0.3 U/ml vs. 17.9+/-0.2 U/ml, p<0.01, men: 19.4+/-0.3 U/ml vs. 20.4+/-0.3 U/ml, p=0.03). Additionally, the CC genotype of this mutation was more common in the male DVT patients than in the male individuals of the general population (odds ratio=2.76, 95% confidence interval=1.14-6.67; p=0.02). This mutation was in linkage disequilibrium (r-square>0.9) with A455V mutation. CONCLUSIONS: TM mutations, especially those with a haplotype consisting of 2729A>C and A455V missense mutation, affect sTM levels, and may be associated with DVT in Japanese.     

Protein Z influences the prothrombotic phenotype in Factor V Leiden patients

Protein Z enhances the inhibition of factor Xa by protein Z-dependent protease inhibitor (ZPI). Thus, diminution of protein Z should induce prothrombotic tendency due to lowered cofactor activity for ZPI. In Factor V Leiden mice, prothrombotic tendency of severe diminution or lack of protein Z was demonstrated. We here present first studies in humans, indicating that diminution of protein Z in factor V Leiden patients aggravates thromboembolic risk.     

Comparative fibrinolytic properties of staphylokinase and streptokinase in animal models of venous thrombosis.

The thrombolytic and pharmacokinetic properties of staphylokinase were compared with those of streptokinase in hamsters with a pulmonary embolus produced from human plasma or from hamster plasma, and in rabbits with a jugular vein blood clot produced from rabbit blood. In both models, a continuous intravenous infusion of staphylokinase and streptokinase over 60 min in hamsters or over 4 h in rabbits, induced dose-dependent progressive clot lysis in the absence of significant systemic activation of the fibrinolytic system. The results of thrombolytic potency (clot lysis at 30 min after the end of the infusion, in percent, versus dose administered, in mg/kg) were fitted with an exponentially transformed sigmoidal function (formula: see text) and the maximal percent clot lysis (c), the maximal rate of lysis (z = 1/4 ac.eb) and the dose at which the maximal rate of lysis is achieved (b) were determined. In hamsters with a pulmonary embolus produced from human plasma, streptokinase had a somewhat higher thrombolytic potency than staphylokinase, as revealed by a higher z value (2,100 +/- 1,100% lysis per mg/kg streptokinase administered versus 1,100 +/- 330% lysis per mg/kg for staphylokinase). In hamsters with a pulmonary embolus produced from hamster plasma, staphylokinase had a somewhat higher thrombolytic potency than streptokinase (z = 1,600 +/- 440 versus 1,200 +/- 370% lysis per mg/kg). Staphylokinase had a higher thrombolytic potency than streptokinase in rabbits,as revealed by a higher z-value (950 +/- 350% lysis per mg/kg staphylokinase administered versus 330 +/- 39% lysis per mg/kg for streptokinase) and a lower b-value (0.035 +/- 0.010 mg/kg staphylokinase versus 0.091 +/- 0.008 mg/kg for streptokinase.(ABSTRACT TRUNCATED AT 250 WORDS)     

Talampanel a non-competitive AMPA-antagonist attenuates caspase-3 dependent apoptosis in mouse brain after transient focal cerebral ischemia

Talampanel (IVAX) is a non-competitive AMPA-antagonist has a remarkable neuroprotection in different rodent stroke models. The focal cerebral ischemia in mice was induced by transient (60 min.) MCA occlusion and 48 h reperfusion and treated with talampanel (6 x 2 mg/kg, i.p.). The apoptotic and necrotic cells were analyzed by double immune histochemical staining on confocal laser microscope. The infarct size is decreased significantly by talampanel treatment (from 57.1+/-7.2mm(2) to 18.9+/-2.6 mm(2), p< 0.001). The number of TUNEL-positive cells localized mostly in the border zone of ischemic lesions is significantly decreased after talampanel treatment (from 962+/-13.0 to 604+/-6.9, p < 0.01). A strong, significant reduction of caspase-3 active cells was visualized. Talampanel as a neuroprotective drug candidate has a significant effect in mice transient MCA occlusion model.     

Etiological analysis of presumed perinatal stroke

This study aimed to investigate the maternal, pre- and perinatal, and prothrombotic factors with congenital hemiparesis due to presumed perinatal stroke (PPS). Prothrombotic risk factors including protein C and S, antithrombin III, lipoprotein (a), homocystein, factor VIII levels; anticardiolipin antibodies and lupus anticoagulant; methylenetetrahydrofolate reductase mutations, factor V Leiden, prothrombin G20210A mutations were investigated. Arterial ischemic stroke was detected in 60% and periventricular venous infarction in 40%. At least one prothrombotic risk factor was present in 69%, two in 17%, and three or more in 8.5% of cases. The most common combination was methylenetetrahydrofolate reductase C677T and factor V Leiden heterozygosity. The etiology and pathogenesis of PPS is still unclear. According to this study, most of the patients with PPS might have one or more prothrombotic risk factors and certain prenatal risk factors including intrauterine growth retardation, twin gestation and preeclampsia might be related to PPS.     

Plasmin generation plays different roles in the formation and removal of arterial and venous thrombus in mice

The role of plasminogen (Plg) and alpha2-antiplasmin (alpha2-AP) in vascular thrombolysis in vivo was investigated in mice deficient in plasminogen (Plg-/-) or a2-AP (alpha2-AP-/-) or their wild type (PAI-1+/+, alpha2-AP+/+). A thrombus was induced in the murine carotid artery or the internal jugular vein by endothelial injury. Blood flow was continuously monitored for 90 min and for 6 h 30 min after the initiation of endothelial injury. The times to occlusion by the developing thrombus in the carotid artery and the jugular vein of wild type mice were 12+/-1.8 and 7.2+/-1.9 min, respectively. The arterial thrombus formation in alpha2-AP-/- mice was indistinguishable from the one in wild type mice, whereas the time to occlusion in Plg-/- was significantly shortened to 5.9+/-1.7 min. Vascular patency after spontaneous reperfusion was markedly improved in alpha2-AP-/- mice. On the contrary, arteriarpatency in Plg-/- mice was aggravated. In venous thrombus formation, the time to occlusion in alpha2-AP-/- mice was significantly prolonged (27.1+/-5.2 min), whereas in Plg-/- it was slightly shortened to 6.5+/-2.5 min. Vascular patency after spontaneous reperfusion was also improved in alpha2-AP-/- mice, but not in Plg-/- mice. Histological observations using SEM indicated that fibrin nets were firmly fixed on the injured area in Plg-/- mice, but not in alpha2-AP-/- mice. The tail bleeding time was not different in any type of mice. However, re-bleeding time using a template bleeding device was significantly prolonged in alpha2-AP-/- as compared with that of wild type mice. In conclusion, lack of plasminogen markedly reduces the antithrombotic activities in vivo, whereas alpha2-AP plays a more important role in the formation and removal of venous thrombus in mice. Consequently, the inhibition of alpha2-AP could be a useful tool for the therapy of venous thrombosis and the prevention of re-thrombus formation.