Fibrin accumulation plays a critical role in the sensitization to lipopolysaccharide-induced liver injury caused by ethanol in mice

The early stages of alcohol-induced liver injury involve chronic inflammation. Whereas mechanisms by which this effect is mediated are not completely understood, it is hypothesized that enhanced sensitivity to circulating lipopolysaccharide (LPS) contributes to this process. It has recently been shown that ethanol induces activation of plasminogen activator inhibitor-1 (PAI-1). PAI-1 causes fibrin accumulation in liver by inhibiting degradation of fibrin (fibrinolysis). LPS also enhances fibrin accumulation by activating the coagulation cascade. It was therefore hypothesized that ethanol will synergistically increase fibrin accumulation caused by LPS, enhancing liver damage. Accordingly, the effect of ethanol pretreatment on LPS-induced liver injury and fibrin deposition was determined in mice. Ethanol enhanced liver damage caused by LPS, as determined by plasma parameters and histological indices of inflammation and damage. This effect was concomitant with a significant increase in PAI-1 expression. Extracellular fibrin accumulation caused by LPS was also robustly increased by ethanol preexposure. Coadministration of the thrombin inhibitor hirudin or the MEK (mitogen-activated protein kinase) inhibitor U0126 significantly attenuated the enhanced liver damage caused by ethanol preexposure; this protection correlated with a significant blunting of the induction of PAI-1 caused by ethanol/LPS. Furthermore, thrombin/MEK inhibition prevented the synergistic effect of ethanol on the extracellular accumulation of fibrin caused by LPS. Similar protective effects on fibrin accumulation were observed in tumor necrosis factor receptor 1 (TNFR-1)(-/-) mice or in wild-type injected with PAI-1-inactivating antibody.

CONCLUSION

These results suggest that enhanced LPS-induced liver injury caused by ethanol is mediated, at least in part, by fibrin accumulation in livers, mediated by an inhibition of fibrinolysis by PAI-1. These results also support the hypothesis that fibrin accumulation may play a critical role in the development of early alcohol-induced liver injury.

[Soluble fibrin is not excreted in urine and its plasma level is elevated in nephrotic syndrome]

Soluble fibrin (SF) is produced by activated blood coagulation reaction and is useful to diagnose thrombotic diseases. We measured plasma and urine SF levels in nephritic patients to assess the hypercoagulability state associated with the disease. Before they received anti-coagulation or anti-platelet therapies, 60 patients underwent measurement of plasma SF and D-dimer levels by Latex agglutination turbidimetric immnoassay (LA). Urinary SF levels were also measured by LA. Plasma and urinary thrombin antithrombin III complex (TAT) levels were measured by enzyme immunoassay (EIA). Plasma SF levels showed a good correlation with plasma TAT levels but only weak positive correlations were observed between plasma D-dimer and SF or TAT levels. Plasma SF and D-dimer levels were significantly higher in the Iatients with nephrotic-range hypoalbuminemia (< or =3 g/dL) than those without it. Contrarily there was no significant difference in plasma TAT levels between these two groups of patients. In almost all patients, urinary SF levels were under the detection limit. However, TAT was excreted into urine more frequently in patients showing the nephrotic range of hypoalbuminemia at 38.2% than in non-nephrotic patients at 8.0%. Thus, plasma SF levels more precisely indicate activated blood coagulation reaction than plasma TAT levels in nephrotic patients, probably because the plasma SF is not excreted into urine, while plasma TAT is.

Proteolytic enzyme activity as a result of aging

BACKGROUND AND AIMS

The extracellular matrix (ECM) undergoes constant dynamic changes; proteolytic enzymes, particularly the serine proteases plasmin, trypsin and elastase, catalyze critical functions in these processes. Notably, ECM degradation disorders have been reported in various morbid conditions, including cardiac infarction, atheromatosis, and neoplastic diseases, indicating a physiological requirement for proper ECM maintenance. Here we define the role of proteolytic enzymes in the development of aging by assessing changes in proteolytic enzyme activity in serum during aging in rats.

METHODS

The activities of trypsin, elastase and plasmin in rat serum were determined by the fluorometric method using AMC-labeled substrates in 34Wistar rats divided into four age groups: 3 month-olds (n=8), 9 month-olds (n=8), 15 month-olds (n=8) and 24 month-olds (n=10).

RESULTS

Analysis of proteolytic enzyme activity in four age-dependent groups revealed that in comparison to their 3, 9, and 24 month-old counterparts, the 15 month-old rats exhibited a statistically significant increase in average elastase activity. In accordance with previous studies, a statistically significant increase in trypsin levels was found in the 3 month-old rats, suggesting that trypsin activity decreases with age. Average plasma plasmin activity in the 24 month-old rats was, moreover, statistically significantly higher than that in the other three age groups.

CONCLUSIONS

Analysis of combined proteolytic activity indicates that age-dependent patterning of blood serine protease enzyme activity may be related to age-related diseases.

Thrombin activatable fibrinolysis inhibitor and other hemostatic parameters in patients with polycystic ovary syndrome

OBJECTIVES

To investigate the plasma levels of thrombin-activatable fibrinolysis inhibitor (TAFI) in women with polycystic ovary syndrome (PCOS) and its correlation with various metabolic, hormonal and hemostatic parameters.

METHODS

Forty-eight women with PCOS and 43 age- and BMI-matched ovulatory controls were recruited during a 20-month study period. Blood samples were drawn for all tests, which included plasma lipids and lipoproteins, reproductive hormones, glucose, insulin, TAFI antigen concentration, plasminogen activator inhibitor-1 (PAI-1) activity, fibrinogen concentration, thrombomodulin, thrombin-antithrombin (TAT) complexes, D-dimer, Protein C Antigen, Protein S Antigen, Antithrombin III (AT III) and activated protein C (APC) resistance.

RESULTS

Plasma TAFI levels of PCOS patients were found to be significantly higher than in healthy controls (93.8%+/-30.6%vs. 79.8% +/- 22.4%, p < 0.05). Plasma levels of D-dimer, AT III, PAI-1 and thrombomodulin were also significantly higher in women with PCOS compared with healthy controls. All the other hemostatic parameters (including TAT complexes; Protein C; APC; and Protein S) were comparable between the two study groups.

CONCLUSION

This study showed that plasma levels of TAFI, PAI-1, D-dimer, AT III and thrombomodulin were significantly increased in women with PCOS compared with age- and BMI-matched controls.

[Clinical and laboratory features of different forms of osteoarthrosis]

Inflammation is currently believed not only to influence clinical manifestations ofosteoarthrosis (OA) but also to be a key pathogenetic link in the chain reaction underlying progress of the disease. Patients with OA and signs of local inflammation undergo a change of algofunctional index and markers of inflammation, such as C-reactive protein (C-RP) and interleukin-6 (IL-6). Inflammation markers in patients with isolated disease of large joints are more affected than in women with OA and concomitant pathologies. Increased levels of C-RP and IL-6 in women with gonarthrosis/coxarthrosis confirm the key role of inflammation in the progress of this OA variant. Imbalance of IL-6 and its soluble receptors is an indicator of substantial impairment of the adaptive capacity in these patients. Elevated C-RP and IL-6 levels in patients with OA suggest chronic inflammation in patients with degenerative-dystrophic joint affection. Derangement of compensatory and adaptive processes in OA is associated with chronic immuno-inflammatory changes accompanied by hypersecretion of cytokines and proteolitic enzymes. Aggressive action of inflammation mediators in isolated affection of large joints accounts for the predominance of catabolic processes over anabolic ones which leads to further progress of OA due to low efficiency of the recovery of cartilage tissue and activation of its destruction. OA with concomitant pathologies leads to the disturbance of coordinated inflammatory response and cytokine cascade associated with inadequate IL-6 production. It is concluded that local and systemic immunopathologic processes in patients with OA form a vicious circle and contribute to the progress of degenerative-dystrophic processes in the joints.

Activation of the fibrinolytic cascade early in pregnancy among women with spontaneous preterm birth

OBJECTIVE

To evaluate the association of early pregnancy concentrations of thrombin-antithrombin III complex with subsequent spontaneous preterm birth.

METHODS

In a nested case-control study, thrombin-antithrombin III complex was measured in plasma before 20 weeks of gestation (mean 9.9 weeks) among women without chronic conditions, preeclampsia, or growth restriction. C-reactive protein and non-high-density lipoprotein cholesterol were also measured. Women with spontaneous preterm birth before 34 weeks of gestation (n=29) and 34 weeks to 36 weeks of gestation (n=72) were compared with women with term births occurring at or after 37 weeks (n=219). Polychotomous logistic regression was used to relate elevated thrombin-antithrombin III complex (greater than 5.5 ng/mL), dyslipidemia (non-high-density lipoprotein cholesterol greater than the 90th percentile), and inflammation (C-reactive protein at or above 8 micrograms/mL) to risk of spontaneous preterm birth subtypes.

RESULTS

Women with spontaneous preterm birth compared with term births had elevated thrombin-antithrombin III complex (P=.02), and they were more likely to have a thrombin-antithrombin III complex greater than 5.5 ng/mL (P<.01). Women with thrombin-antithrombin III complex in the highest compared with lowest quartile had a 4.6-fold (95% confidence interval 1.3-15.8) increased risk for spontaneous preterm birth before 34 weeks of gestation, adjusted for body mass index, race, inflammation, dyslipidemia, and gestational age at sampling. There was a dose-response trend between thrombin-antithrombin III complex and spontaneous preterm birth before 34 weeks (P<.01) and 34 to 36 weeks (P=.03).

CONCLUSION

There is evidence of early pregnancy systemic fibrinolysis among women with spontaneous preterm birth before 34 weeks of gestation independent of inflammation and dyslipidemia, perhaps secondary to microvascular injury.

LEVEL OF EVIDENCE

II.

Tissue factor +5466A>G polymorphism determines thrombin formation following vascular injury and thrombin-lowering effects of simvastatin in patients with ischemic heart disease

OBJECTIVE

We examined the hypothesis that the +5466A>G variant (rs3917643) of the tissue factor (TF) gene is associated with thrombin formation following simvastatin in patients with ischemic heart disease (IHD).

METHODS AND RESULTS

Prothrombin 1.2 fragments (F1.2) and thrombin-antithrombin complexes (TAT) were assessed in 95 men with stable IHD, aged 54.4+/-6.8 years, in blood collected every 60s from the bleeding-time wounds before and after a 3-month simvastatin administration (40 mg/day). We identified 16 patients with the TF +5466AG genotype and 79 subjects with the +5466AA genotype. Baseline maximum rates of F1.2 and TAT formation and their maximum levels at the site of vascular injury, but not in venous blood, were higher in +5466G allele carriers than in those with +5466AA genotype (P<0.0001). The magnitude of reduction in maximum rates of F1.2 and TAT formation following simvastatin was larger (P<0.001) in +5466G allele carriers than in +5466AA subjects. The degree of decrease in maximum local levels of F1.2 and TAT after simvastatin was similar in both genotype groups. The presence of the +5466G allele was independently associated with the maximum velocity of F1.2 and TAT generation and maximum levels of both markers before and after simvastatin in multiple regression models (P<0.01 for all analyses). Local thrombin generation, in +5466AG and +5466AA subjects, showed no significant correlations with lipid variables.

CONCLUSIONS

Thrombin formation following vascular injury and thrombin-lowering effect of statins in patients with IHD are at least in part genetically determined by the TF +5466A>G polymorphism.

[Determination of protease activity in blood and in microorganisms]

For determination of protease activity it is possible to use immunoglobulins. Since proteolytic products apparently do not retain substrate antigenic determinants, it is possible to use ELISA methodsfor monitoring for enzymatic process. ELISA determination of functional activity of specific IgA1-protease has been applied not only for detection of this enzyme, but also for measurement of its inhibition constants. Fixed on a micropanel IgG may be used for evaluation of total proteolytic activity. Depending on pH values, it is possible to measure activity of neutral, alkaline and acid proteases. This approach has allowed to estimate total proteolytic activity of neutral proteases of serum. Measurement of a total level of serum pepsinogene activity can have diagnostic importance in gastroenterology, due to decisive contribution of pepsinogen I to the measured activity.

Spiking of serum specimens with exogenous reporter peptides for mass spectrometry based protease profiling as diagnostic tool

Serum is a difficult matrix for the identification of biomarkers by mass spectrometry (MS). This is due to high-abundance proteins and their complex processing by a multitude of endogenous proteases making rigorous standardisation difficult. Here, we have investigated the use of defined exogenous reporter peptides as substrates for disease-specific proteases with respect to improved standardisation and disease classification accuracy. A recombinant N-terminal fragment of the Adenomatous Polyposis Coli (APC) protein was digested with trypsin to yield a peptide mixture for subsequent Reporter Peptide Spiking (RPS) of serum. Different preanalytical handling of serum samples was simulated by storage of serum samples for up to 6 h at ambient temperature, followed by RPS, further incubation under standardised conditions and testing for stability of protease-generated MS profiles. To demonstrate the superior classification accuracy achieved by RPS, a pilot profiling experiment was performed using serum specimens from pancreatic cancer patients (n = 50) and healthy controls (n = 50). After RPS six different peak categories could be defined, two of which (categories C and D) are modulated by endogenous proteases. These latter are relevant for improved classification accuracy as shown by enhanced disease-specific classification from 78% to 87% in unspiked and spiked samples, respectively. Peaks of these categories presented with unchanged signal intensities regardless of preanalytical conditions. The use of RPS generally improved the signal intensities of protease-generated peptide peaks. RPS circumvents preanalytical variabilities and improves classification accuracies. Our approach will be helpful to introduce MS-based proteomic profiling into routine laboratory testing.

Heparin-coated extracorporeal circulation in combination with low dose systemic heparinization reduces early postoperative blood loss in cardiac surgery

AIM

According to a recently performed meta-analysis, heparin-bonded circuits do not reduce blood loss in cardiac surgery patients compared to nonheparin-bonded circuits within the first 24 h postoperatively. We investigated the effects of heparin-coated circuits in combination with a reduced systemic heparin dose on early postoperative blood loss (first 12 h), platelet function, and postoperative complications.

METHODS

Patients who underwent their first coronary artery bypass graft surgery were included in a randomized prospective study. Group A (n=149) was perfused with an uncoated extracorporeal circulation (ECC)-set and groups B (n=152) and C (n=149) with heparin-coated ECC-sets. In groups A and B, conventional dose systemic heparin was given, whereas group C received low dose systemic heparin. Blood loss was assessed within the first 12 h postoperatively. Moreover, biochemical parameters of pro-coagulant activity and immunological function were measured.

RESULTS

None of the pro-coagulant activity markers and immunological parameters measured differed preoperatively or postoperatively between study groups. However, intraoperative platelet counts and maximal intraoperative concentrations of platelet factor 4, ss-thromboglobulin, and poly-morpho-nuclear (PMN)-elastase were lowest in group C, whereas group C also had the highest concentrations of thrombin-antithrombin complex (P<0.018-0.001). Blood loss within the first 12 h postoperatively was 457 +/- 204 mL in group A, 431 +/- 178 mL in group B, and 382 +/- 188 mL in group C (P<0.01). Complication rates and 30-day mortality did not differ between study groups.

CONCLUSION

The combined use of heparin-coated circuits and low dose systemic heparinization is able to reduce early postoperative blood loss without enhancing the risk of complications.

Endothelial dysfunction in adult patients with a history of Kawasaki disease

To assess the existence of endothelial dysfunction and the possibility of the early onset of atherosclerosis in the chronic stage of Kawasaki disease (KD), we examined endothelial function in adult patients late after the onset of KD. We evaluated two age-matched groups: 35 adult KD patients (KD group) (mean age, 27.0 years; mean interval time, 24.1 years), and 36 healthy adults (control group). To assess vascular endothelial function, flow-mediated dilatation (%FMD) of the brachial artery and urinary nitrites and nitrates (NOx) were examined. We also measured adhesion molecules and several coagulation-fibrinolysis markers. In addition, we measured high-sensitive C-reactive protein (hs-CRP) as a chronic inflammatory marker, and brachial-ankle pulse wave velocity (baPWV) as a marker for arterial stiffness. %FMD was significantly reduced in the KD group when compared with that of the control group (KD group, 10.4 +/- 2.6%; control group, 14.4 +/- 3.2%, p<0.05), particularly in patients with coronary artery lesions. Thrombin-antithrombin III complex values were higher in the KD group, although no significant differences were observed in the other markers for endothelial function. Hs-CRP was significantly elevated only in the patients with coronary aneurysms. Furthermore, in the male KD patients, the baPWV values were significantly higher than those in the control subjects. This study revealed that the adult patients with a history of KD had systemic vascular endothelial dysfunction, and also suggested that a history of KD was possibly one of the risk factors for early onset of atherosclerosis.

[Protein C system in patients with idiopathic pulmonary fibrosis--preliminary report]

INTRODUCTION

The natural anticoagulant-activated protein C system plays an important role in the pathogenesis of idiopathic pulmonary fibrosis. The purpose of this study was to evaluate the concentration of protein C (PC), protein S (PS), thrombomodulin (TM), selectin E (sSelE), and thrombin-antithrombin complex (TAT) in patients with idiopathic pulmonary fibrosis (IPF).

MATERIAL AND METHODS

Study group consisted of 11 patients aged 51.5 +/- 8.62 years with idiopathic pulmonary fibrosis and 20 healthy adults as control. Concentration of PC, PS TM, sSelE and TAT in plasma with ELISA method was assessed.

RESULTS

We observed significantly lower plasma concentration of PC (98.24 +/- 16.17% vs. 130.59 +/- 19.03%), PS (71.31 +/- +/- 12.95% vs. 93.47 +/- 18.63%), TM (2.67 +/- 0.40 ng/ml vs. 3.99 +/- 1.16 ng/ml) and significantly higher level of TAT complex (Me = 4.00 mg/ml vs. 2.20 mg/ml) and sSelE (Me = 36.40 ng/ml vs. 22.84 ng/ml) in patients with idiopathic pulmonary fibrosis as compared to controls.

CONCLUSION

In presented pilot study we observed decreased activity of protein C system and increased thrombin generation in peripheral blood of patients with idiopathic pulmonary fibrosis.

Heamostatic and genetic predisposing factors for stroke in children with sickle cell anemia

Sickle cell disease (SCD) is a group of genetic disorders characterized by the production of the abnormal hemoglobin S (HbS). Sickle cell anemia (SCA) is the most common type of SCD and represents the homozygous form, in which the individual inherits a double dose of the abnormal gene that codes for hemoglobin S. This study was done to detect cases of silent and clinically overt strokes in children with sickle cell anemia (SCA) and examine predisposing factors for stroke development. The study included 20 children with clinically and hematologically confirmed SCA and 10 controls. They were divided into two groups, group I; included 10 steady state cases and group II; included 10 cases with thrombotic crisis. All subjects were subjected to full clinical examination, measurements of plasma level of: fibrinopeptid A (FPA), thrombin-antithrombin III (TAT), fibrin degradation product (D-dimer) and serum level of platelet endothelial cell adhesion molecule-1 (PECAM-1), and analysis of the ACE gene polymorphism by polymerase chain reaction (PCR). Patients were further subjected to Brain computed axial tomography (CT) scan and/or magnetic resonance imaging (MRI) as well as electro-encephalographic studies (EEG). Silent ischemic brain infarction as evidenced by CT scan and/or MRI was present in one patient in group I (10%) and one patient in group II (10%). On the other hand, two patients in group II (20%) showed clinically overt strokes. Thus, 4 children had silent or clinically overt stroke and the remaining 16 were non-stroke cases. Laboratory results showed that the levels of FPA, TAT, D-dimer and PECAM-1 were significantly elevated in SCA patients both in the steady and crisis states as compared to control, with more evident significant elevation in group II (thrombotic crisis) as compared to group I (steady state). The stroke group showed significant elevation; FPA, TAT, D-dimer and PECAM-1 as compared with non-stroke group. The PCR results showed that the frequencies of both DD genotype and D allele of ACE gene in the thrombotic crisis are significantly higher than in the control group and that all stroke children are of DD genotype. In conclusion, significant increase in FPA, TAT, D-dimer and PECAM-1 levels as well as the presence of ACE D allele of the ACE gene are significant predisposing factors for stroke in children with SCA. Regular follow-up by thorough neurological examination and neuro-imaging studies for early detection of silent brain infarction is recommended.

Elevated levels of prothrombin fragment 1 + 2 indicate high risk of thrombosis

Prothrombin fragment 1 + 2 (F1 + 2) is considered to be useful for diagnosis of thrombosis. However, the evidence for a diagnosis of thrombosis by F1 + 2 is still not well established. The plasma concentrations of F1 + 2, soluble fibrin, D-dimer, and thrombin-antithrombin complex were measured in 694 patients suspected of having thrombosis and then were correlated with thrombosis. Plasma concentrations of F1 + 2, soluble fibrin, D-dimer, and thrombin-antithrombin complex were significantly higher in patients with thrombosis, compared with patients without thrombosis. When cutoff values of more than 300 pmol/L for F1 + 2 were used for the diagnosis, more than 50% of the patients were thus found to have thrombosis. The findings showed that F1 + 2, soluble fibrin, D-dimer, and thrombin-antithrombin complex have similar diagnostic ability. The plasma concentration of F1 + 2 closely was well correlated with thrombin-antithrombin complex, soluble fibrin, and D-dimer. Finally, F1 + 2 is one of the most useful parameters for the diagnosis of thrombosis.

Fibrin monomer complex in normal pregnant women: a potential thrombotic marker in pregnancy

BACKGROUND

Pregnancy represents a major risk factor for deep vein thrombosis (DVT). Most coagulation/fibrinolysis markers currently utilized change during pregnancy, and therefore they cannot accurately evaluate thrombotic events in pregnancy because the rate of false positive results is high. Fibrin monomer complex (FMC) has recently become widely available for diagnosing DVT. The present study examined whether FMC is suitable for evaluating thrombotic status in pregnancy.

METHODS

Concentrations of FMC and other haemostatic markers were investigated in 87 pregnant women without major complications at early, mid- or late pregnancy. FMC concentrations were also measured in 127 normal non-pregnant women, and in one woman who developed DVT after delivery.

RESULTS

In normal pregnant women, FMC concentrations were unchanged during early or mid-pregnancy and slightly elevated during late pregnancy. Concentrations were within reference range in most cases, and none exceeded the cut-off value for DVT. In contrast, thrombin-antithrombin complex (TAT) and D-dimer (DD) concentrations were significantly elevated in late pregnancy, and median values exceeded reference ranges. The DVT case displayed significantly elevated FMC concentrations.

CONCLUSIONS

Changes in FMC concentrations during normal pregnancy are minimal compared with other haemostatic markers. Because the rate of false positivity is lower, FMC could be a potential marker of thrombotic status in pregnancy rather than TAT and DD.

In vitro and in vivo degradation of Abeta peptide by peptidases coupled to erythrocytes

It is generally believed that amyloid beta peptides (Abeta) are the key mediators of Alzheimer's disease. Therapeutic interventions have been directed toward impairing the synthesis or accelerating the clearance of Abeta. An equilibrium between blood and brain Abeta exists mediated by carriers that transport Abeta across the blood-brain barrier. Passive immunotherapy has been shown to be effective in mouse models of AD, where the plasma borne antibody binds plasma Abeta causing an efflux of Abeta from the brain. As an alternative to passive immunotherapy we have considered the use of Abeta-degrading peptidases to lower plasma Abeta levels. Here we compare the ability of three Abeta-degrading peptidases to degrade Abeta. Biotinylated peptidases were coupled to the surface of biotinylated erythrocytes via streptavidin. These erythrocyte-bound peptidases degrade Abeta peptide in plasma. Thus, peptidases bound to or expressed on the surface of erythroid cells represent an alternative to passive immunotherapy.

Tissue factor-dependent blood coagulation is enhanced following delivery irrespective of the mode of delivery

BACKGROUND

The risk of thrombosis is clearly increased in the postpartum period. Mice with a targeted deletion of the transmembrane domain of tissue factor (TF) develop serious activation of blood coagulation and widespread thrombosis after delivery.

OBJECTIVE AND METHODS

We hypothesized that TF, abundantly present in placental tissue, is released during delivery, resulting in the activation of blood coagulation. We measured sensitive markers for TF-dependent activation of coagulation before and after induction of labor in two groups: a vaginal delivery (VAG) group and a cesarean section (CS) group.

RESULTS

One hour after delivery, soluble TF (sTF) significantly increased in both groups [VAG group (mean +/- SD) 226 +/- 42 to 380 +/- 42 pg mL(-1) and CS group 193 +/- 17 to 355 +/- 44 pg mL(-1)]. The day after delivery, sTF was somewhat less increased. Both groups also showed an increase in factor VIIa, indicating activation of the TF pathway of coagulation. Indeed, after delivery, TF-dependent coagulation, as measured by the TF clotting time assay, was significantly enhanced. Increased plasma levels of prothrombin fragment 1 + 2 and thrombin-antithrombin complexes demonstrated thrombin generation following delivery. TF pathway-dependent activation of coagulation upon delivery was not blocked by TF pathway inhibitor and was not dependent on the mode of delivery.

CONCLUSION

The postdelivery increase in TF-dependent activation of coagulation is likely to be a natural mechanism to prevent excessive blood loss during and after delivery, and may also indicate a novel mechanism by which puerperal women have an increased risk of venous thromboembolism.

Plasma protein Z and protein C inhibitors and their role in hypercoagulability of thalassemia

A hypercoagulable state has been described in thalassemia patients, partly due to a deficiency of inhibitors, protein C (PC) in particular. Since a potential role of a new hemostatic factor named protein Z (PZ) has been reported in hypercoagulability, we evaluated plasma PZ and PC levels in thalassemia and their possible relation to the hypercoagulable state. Sixty subjects with thalassemia major and 10 with thalassemia intermedia (TI) followed at our Department were enrolled in the study. An age-matched control group of healthy subjects was considered. PZ, thrombin-antithrombin complexes, PC concentration (PC:Ag) and activity (PC:Act) were measured. PZ, PC:Ag and PC:Act were significantly lower in thalassemia major and thalassemia intermedia subjects than in 30 healthy controls (p < 0.001), while thrombin-antithrombin complex levels were significantly increased (p < 0.001) and related to PC levels but not to PZ levels (p < 0.05). PZ and PC levels are reduced in thalassemia but only PC has an effect on the thalassemia hypercoagulable state.

Hemostatic biomarkers in dogs with chronic congestive heart failure

BACKGROUND

Chronic congestive heart failure (CHF) in humans is associated with abnormal hemostasis, and abnormalities in hemostatic biomarkers carry a poor prognosis. Alterations in hemostatic pathways can be involved in the pathogenesis of CHF in dogs, and microthrombosis in the myocardium could contribute to increased mortality.

HYPOTHESIS

That plasma concentration or activity of hemostatic biomarkers is altered in dogs with CHF and that these factors predict mortality.

ANIMALS

Thirty-four dogs with CHF caused by either dilated cardiomyopathy (DCM, n=14) or degenerative valvular disease (CDVD, n=20) compared with 23 healthy age-matched control dogs were included in this study. Dogs with CHF were recruited from 2 referral cardiology clinics, and control dogs were owned by friends or colleagues of the investigators.

METHODS

Clinical examination and echocardiography were performed in all dogs. Plasma fibrinogen and D-dimer concentrations, antithrombin and protein C activity, and thrombin-antithrombin complex (TAT) were measured in all dogs.

RESULTS

Dogs with CHF had significantly higher fibrinogen (P = .04), D-dimer (P = .002), and TAT concentration (P < .0001), lower antithrombin (P < .0001) and protein C activity (P < .001) compared with control dogs. None of the hemostatic biomarkers were associated with risk of death.

CONCLUSIONS AND CLINICAL IMPORTANCE

There is evidence of a procoagulant state in dogs with CHF. The lack of predictive value for survival might be due to the small number of dogs examined. Further studies are necessary to investigate the presence and importance of microthrombosis in dogs with CHF.

The effect of dalteparin on coagulation activation during pregnancy in women with thrombophilia. A randomized trial

Low-molecular-weight heparin (LMWH) is increasingly being used for prophylaxis of venous thromboembolism (VTE) and prevention of pregnancy associated morbidity in pregnant women with thrombophilia. We sought to determine if the administration of prophylactic doses of LMWH downregulates coagulation activation in high risk pregnant women with thrombophilia. This sub-study was planned as part of a randomized open label controlled trial (Thrombophilia in Pregnancy Prophylaxis Study [TIPPS]) in which patients at high risk of pregnancy complications with confirmed thrombophilia are randomized to receive either dalteparin (5,000 units/day until 20 weeks then 5,000 units q12h until 37 weeks or onset of labor) or no treatment. Blood samples were collected at baseline, day 7-9 (after starting study drug), week 20 (before increasing study drug), week 36 (prior to stopping study drug) and at the time of admission to the labor and delivery unit. Samples were not drawn at fixed times in relation to drug injection. These samples were analyzed for levels of thrombin-antithrombin complexes (TAT), prothrombin fragments 1 + 2 (F1.2), D-dimer and anti-Xa activity. Generalized linear mixed models were used for statistical analysis and model results were controlled for age, smoking status, type of thrombophilia and predisposing risk factors. The effect of dalteparin on TAT levels was defined as the primary outcome. Of 198 patients eligible, 114 were enrolled in TIPPS. Ninety-one were eligible for the TIPPS coagulation activation sub-study and randomized. Thirty-nine patients were analyzed in the treatment group (dalteparin) and 46 patients in the control group (no intervention). Levels of coagulation activation factors F1.2, TAT and D-dimer increased significantly throughout pregnancy in both groups (p < 0.0001). Dalteparin prophylaxis resulted in a significant increase in anti-Xa activity through pregnancy (p < 0.0001) compared to controls. Dalteparin had no significant effects on the levels of TAT, F1.2 and D-dimer throughout pregnancy in thrombophilic women. A post-hoc Monte Carlo power analysis revealed that our study had 100% and 88% power to detect reductions in TAT values on treatment of 50% and 25%, respectively. Prophylaxis with dalteparin at doses used in this study did not reduce coagulation activation in high risk thrombophilic women during pregnancy.

Successful kidney transplantation does not reverse the coagulopathy in patients with chronic renal failure on either hemo or peritoneal dialysis

There is wide disagreement about the measurement of various hemostatic parameters in patients with chronic renal failure (CRF) concerning treatment with either hemodialysis (HD) or continuous ambulatory peritoneal dialysis (CAPD). This study aims to characterize the coagulopathy in patients with CRF both before initiating dialysis, when the patients are expected to have a steady hemostatic state and after starting regular HD or CAPD. The measurements were repeated in a group of patients who received a successful renal transplant to see whether the coagulopathy associated with CRF would be corrected by this lasting therapy. The study, which was mainly cross-sectional and prospective, included two groups: 49 patients with CRF with their age ranging from 17 to 67 years were divided as follows: those on regular HD (n=20), CAPD (n=9) and patients after transplant (n=20). The tests were also done on 34 healthy controls. Significant hyper-fibrinogenemia was recorded in all three study groups. The HD group showed significant elevation in the plasma levels of AT III and total protein S and a significant reduction in free protein S and protein C, when compared with healthy controls. These inhibitors, except total PS, displayed similar fluctuations in the CAPD group. In the transplant patients, there was significant elevation of AT III and total protein S, a reduction in free PS and no significant changes in PC levels. A significant elevation was found in the levels of F1+2, TAT and D-Dimer in HD and in transplant patients, when compared with controls. In CAPD patients, only D-Dimer levels showed a significant increase. The tPA and PAI-1 levels in the three study groups were similar to the control group. Our study revealed significant activation of the hemostatic system, more pronounced in patients on HD than CAPD. This coagulopathy remained only partly corrected following successful kidney transplantation.