Self-anticoagulant sponge for whole blood auto-transfusion and its mechanism of coagulation factor inactivation.

Clinical use of intraoperative auto-transfusion requires the removal of platelets and plasma proteins due to pump-based suction and water-soluble anticoagulant administration, which causes dilutional coagulopathy. Herein, we develop a carboxylated and sulfonated heparin-mimetic polymer-modified sponge with spontaneous blood adsorption and instantaneous anticoagulation. We find that intrinsic coagulation factors, especially XI, are inactivated by adsorption to the sponge surface, while inactivation of thrombin in the sponge-treated plasma effectively inhibits the common coagulation pathway. We show whole blood auto-transfusion in trauma-induced hemorrhage, benefiting from the multiple inhibitory effects of the sponge on coagulation enzymes and calcium depletion. We demonstrate that the transfusion of collected blood favors faster recovery of hemostasis compared to traditional heparinized blood in a rabbit model. Our work not only develops a safe and convenient approach for whole blood auto-transfusion, but also provides the mechanism of action of self-anticoagulant heparin-mimetic polymer-modified surfaces.

Overview of the Therapeutic Potential of Aptamers Targeting Coagulation Factors.

Aptamers are single-stranded DNA or RNA sequences that bind target molecules with high specificity and affinity. Aptamers exhibit several notable advantages over protein-based therapeutics. Aptamers are non-immunogenic, easier to synthesize and modify, and can bind targets with greater affinity. Due to these benefits, aptamers are considered a promising therapeutic candidate to treat various conditions, including hematological disorders and cancer. An active area of research involves developing aptamers to target blood coagulation factors. These aptamers have the potential to treat cardiovascular diseases, blood disorders, and cancers. Although no aptamers targeting blood coagulation factors have been approved for clinical use, several aptamers have been evaluated in clinical trials and many more have demonstrated encouraging preclinical results. This review summarized our knowledge of the aptamers targeting proteins involved in coagulation, anticoagulation, fibrinolysis, their extensive applications as therapeutics and diagnostics tools, and the challenges they face for advancing to clinical use.

Impact of Intraoperative Cell Salvage on Blood Coagulation Factor Concentrations in Patients Undergoing Cardiac Surgery.

BACKGROUND: Cardiothoracic surgery is associated with major blood loss and allogeneic transfusion of red blood cell concentrates. To minimize allogeneic red blood cell (RBC) transfusion, intraoperative cell salvage has been effectively used for years. The objective of this study was to evaluate the impact of cell salvage on blood coagulation factors. METHODS: We enrolled 30 patients scheduled for cardiac surgery in a prospective single-center observational cohort study at an academic hospital. Blood samples from the cell salvage system were obtained from both the reservoir and the processed red blood cell concentrate. Coagulation factors, fibrinogen, antithrombin and von Willebrand activity, and antigen were assessed before and after cell salvage. Statistical analysis was performed using Wilcoxon matched-pairs signed rank test. RESULTS: Our results revealed a significant decrease of fibrinogen (P < .001), coagulation factors II (P = .004), factors VII, X, and XIII (P < .001), and all other measured coagulation factor concentrations/activities in the processed red blood cell concentrate, when compared to the concentrations/activities of the reservoir. CONCLUSIONS: The results of the present study revealed a significant reduction of coagulation factor concentrations/activities by the washing process. Therefore, physicians need to consider adequate management of coagulation in patients with major blood loss and the need of large volumes of RBC transfusion.

Differences between activities of coagulation factors after one month of therapy with different direct oral anticoagulant in pulmonary embolism patients.

WHAT IS KNOWN AND OBJECTIVE: Direct oral anticoagulants (DOACs) are frequently used for the treatment of pulmonary embolism (PE), but both clinical and laboratory data comparing their efficacy and safety are conflicting. This study investigated and compared the impact of three DOACs (apixaban, rivaroxaban and dabigatran) on coagulation cascade in acute PE patients. METHODS: After the initial treatment, acute PE patients were randomly allocated to one of three groups, and treatment continued using one of the three DOACs. Following 1 month of treatment, the activity of factors II, VII and VIII, as well as protein C, antithrombin, D-dimer and fibrinogen, were measured, and the values were compared between the groups. RESULTS AND DISCUSSION: One hundred consecutive PE patients were included. The mean values for the activity of factors II and VII and protein C were higher in patients on apixaban than in patients on rivaroxaban (1.45 ± 1.12 (IU/mL) vs 1.13 ± 0.92 (IU/mL), P < 0.001; 1.24 ± 1.10 (IU/mL) vs 1.05 ± 0.98 (IU/mL), P = 0.024 and 1.15 ± 0.62 vs 1.02 ± 0.68 (IU/mL), P = 0.019, respectively). The mean of factor II activity and the median of factor VIII activity were also significantly higher in patients on apixaban than in patients on dabigatran (1.45 ± 1.12 vs 1.20 ± 0.96 (IU/mL), P = 0.003 and 2.9 (2.0-4.0) vs 2.1 (1.5-2.7) (IU/mL), P = 0.001, respectively). No difference was noticed in D-dimer concentrations, or in the activity of the other factors measured. Additionally, no difference was noticed between the rivaroxaban and dabigatran groups. WHAT IS NEW AND CONCLUSION: Apixaban had a significantly higher thrombin activity, above the laboratory determined normal range, compared to patients on rivaroxaban and dabigatran. This higher thrombin activity in patients on apixaban may contribute to a better haemostatic response during the therapy or increased prothrombotic state after therapy interruption.

Plasma contact factors as therapeutic targets.

Direct oral anticoagulants (DOACs) are small molecule inhibitors of the coagulation proteases thrombin and factor Xa that demonstrate comparable efficacy to warfarin for several common indications, while causing less serious bleeding. However, because their targets are required for the normal host-response to bleeding (hemostasis), DOACs are associated with therapy-induced bleeding that limits their use in certain patient populations and clinical situations. The plasma contact factors (factor XII, factor XI, and prekallikrein) initiate blood coagulation in the activated partial thromboplastin time assay. While serving limited roles in hemostasis, pre-clinical and epidemiologic data indicate that these proteins contribute to pathologic coagulation. It is anticipated that drugs targeting the contact factors will reduce risk of thrombosis with minimal impact on hemostasis. Here, we discuss the biochemistry of contact activation, the contributions of contact factors in thrombosis, and novel antithrombotic agents targeting contact factors that are undergoing pre-clinical and early clinical testing.

Dengue virus causes changes of MicroRNA-genes regulatory network revealing potential targets for antiviral drugs.

BACKGROUND: Dengue virus (DENV) is an increasing global health threat and associated with induction of both a long-lived protective immune response and immune-suppression. So far, the potency of treatment of DENV via antiviral drugs is still under investigation. Recently, increasing evidences suggest the potential role of microRNAs (miRNAs) in regulating DENV. The present study focused on the function of miRNAs in innate insusceptible reactions and organization of various types of immune cells and inflammatory responses for DENV. Three drugs were tested including antiviral herbal medicine ReDuNing (RDN), Loratadine (LRD) and Acetaminophen. RESULTS: By the microarray expression of miRNAs in 165 Patients. Results showed that 89 active miRNAs interacted with 499 potential target genes, during antiviral treatment throughout the critical stage of DENV. Interestingly, reduction of the illness threats using RDN combined with LRD treatment showed better results than Acetaminophen alone. The inhibitions of DENV was confirmed by decrease concentrations of cytokines and interleukin parameters; like TNF-α, IFN-γ, TGF-ß1, IL-4, IL-6, IL-12, and IL-17; after treatment and some coagulants factors increased. CONCLUSIONS: This study showed a preliminary support to suggest that the herbal medicine RDN combined with LRD can reduce both susceptibility and the severity of DENV.

Global deregulation of ginseng products may be a safety hazard to warfarin takers: solid evidence of ginseng-warfarin interaction.

Recent global deregulation of ginseng as the table food raises our concern about the possible ginseng-warfarin interaction that could be life-threatening to patients who take warfarin for preventing fatal strokes and thromboembolism while using ginseng products for bioenergy recovery. Here we show that quality-control ginsenosides, extracted from ginseng and containing its major active ingredients, produce dose- and time-dependent antagonism in rats against warfarin's anti-coagulation assessed by INR and rat thrombosis model. The interactions between ginsenosides and warfarin on thrombosis, pharmacokinetics, activities of coagulation factors and liver cytochrome P450 isomers are determined by using thrombosis analyzer, UPLC/MS/MS, ELISA and real-time PCR, respectively. The antagonism correlates well with the related pharmacokinetic interaction showing that the blood plateaus of warfarin reached by one-week warfarin administration are significantly reduced after three-week co-administration of warfarin with ginsenosides while 7-hydroxywarfarin is increased. The one-week warfarin and three-week warfarin-ginsenosides regimen result in restoring the suppressed levels by warfarin of the coagulating factors II, VII and protein Z, and significantly enhance activities of P450 3A4 and 2C9 that metabolize warfarin. The present study, for the first time, provides the solid evidence to demonstrate the warfarin-ginsenoside interaction, and warns the warfarin users and regulation authorities of the dangerous interaction.

Effects of Modified Qing'e Pill () on expression of adiponectin, bone morphogenetic protein 2 and coagulation-related factors in patients with nontraumatic osteonecrosis of femoral head.

OBJECTIVES: To observe the regulation of Chinese herbal medicine, Modifified Qing'e Pill (, MQEP), on the expression of adiponectin, bone morphogenetic protein 2 (BMP2), osteoprotegerin (OPG) and other potentially relevant risk factors in patients with nontraumatic osteonecrosis of the femoral head (ONFH). METHODS: A total of 96 patients with nontraumatic ONFH were unequal randomly divided into treatment group (60 cases) and control group (36 cases). The treatment group were treated with MQEP while the control group were treated with simulated pills. Both groups were given caltrate D. Six months were taken as a treatment course. Patients were followed up every 2 months. The levels of plasma adiponectin, BMP2, OPG, von Willebrand factor (vWF), von Willebrand factor cleaving protease (vWF-cp), plasminogen activator inhibitor 1 (PAI-1), tissue plasminogen activator (tPA), C-reactive protein (CRP), blood rheology, bone mineral density (BMD) of the femoral head and Harris Hip Score were measured before and after treatment. RESULTS: After 6 months of treatment, compared with the control group, patients in the treatment group had signifificantly higher adiponectin and BMP2 levels (P<0.01 and P=0.013, respectively), lower vWF, PAI-1 and CRP levels (P=0.019, P<0.01 and P<0.01, respectively), and lower blood rheology parameters. BMD of the femoral neck, triangle area and Harris Hip Score in the treatment group were signifificantly higher than those in the control group. Moreover, plasma adiponectin showed a positive association with BMP2 (r=0.231, P=0.003) and a negative association with PAI-1 (r=-0.159, P<0.05). CONCLUSION: MQEP may play a protective role against nontraumatic ONFH by increasing the expression of adiponectin, regulating bone metabolism and improving the hypercoagulation state, which may provide an experimental base for its clinical effects.

The evolution of comprehensive haemophilia care in the United States: perspectives from the frontline.

The establishment of dedicated comprehensive treatment centres more than a half century ago transformed the management of haemophilia in the United States. Formerly, a disease associated with crippling disability and premature death, today, persons with haemophilia who are treated appropriately from infancy and do not develop inhibitors can expect a normal life expectancy and relatively few bleeding episodes. The evolution of the comprehensive haemophilia care, while chastened by the viral epidemics of the 1980s, has been marked by ongoing advances, including prophylaxis, immune tolerance induction, new drugs and gene therapy research. Current challenges include sustaining the comprehensive care model despite decreased funding and expanding the delivery and affordability of comprehensive haemophilia care.

Costs and utilization of treatment in patients with hemophilia.

BACKGROUND: Although hemophilia has a potentially high economic impact, there are no published estimates of healthcare costs for this disease in Portugal. The aim of this study was to evaluate costs of treatment and hospital utilization among patients with hemophilia A and B, with and without inhibitors, over a 3-year period in a Portuguese Comprehensive Care Hemophilia Centre. This is the first study on the financial impact of healthcare costs in patients with hemophilia in Portugal. METHODS: This retrospective, observational study identified patients diagnosed with hemophilia A and B using medical and pharmacy electronic medical records and data from Centro Hospitalar São João, between January 2011 and December 2013. Patients with inhibitors were all high responders (>5 Bethesda Units [BU]). Severity was classified as mild, moderate or severe based on clotting factor levels. Two main outcomes were measured: (1) cost associated with hospital pharmacy claims (clotting factor) and (2) number of hospital visits/hospitalization. RESULTS: A cohort of 103 patients were identified: 72 (69.9 %) with hemophilia A and 31 (30.1 %) with hemophilia B. Among these, five individuals were classified as patients with inhibitors (four with hemophilia A and one with hemophilia B). From the cohort of hemophilia A patients, 36 individuals (35.0 %) were identified as having severe disease; 20 (19.4 %) moderate; and 16 (15.5 %) mild. In the cohort of hemophilia B patients, 14 (13.6 %) were identified as having severe disease; 14 (13.6 %) moderate; and three (2.9 %) mild. The total mean aggregate cost per year (including clotting factor and hospital utilization) for patients with severe hemophilia B was €112,469, compared with €793 for mild hemophilia A. Clotting factor concentrate amounted for 90 % of total cost in severe cases and hospital utilization was also higher in these cases. CONCLUSIONS: Hemophilia treatment is expensive, particularly for patients with severe disease and especially if they develop inhibitors to replacement clotting factors. In our study, severe hemophilia is associated with greater annual total costs in both types of hemophilia (A = €77,587 and B = € 112,469). Patients with inhibitors have costs 3.3 times higher than patients without inhibitors. Age was not associated with significantly greater total costs (clotting factor and hospital visits/hospitalizations).

Maggot excretion products from the blowfly Lucilia sericata contain contact phase/intrinsic pathway-like proteases with procoagulant functions.

For centuries, maggots have been used for the treatment of wounds by a variety of ancient cultures, as part of their traditional medicine. With increasing appearance of antimicrobial resistance and in association with diabetic ulcers, maggot therapy was revisited in the 1980s. Three mechanisms by which sterile maggots of the green bottle fly Lucilia sericata may improve healing of chronic wounds have been proposed: Biosurgical debridement, disinfecting properties, and stimulation of the wound healing process. However, the influence of maggot excretion products (MEP) on blood coagulation as part of the wound healing process has not been studied in detail. Here, we demonstrate that specific MEP-derived serine proteases from Lucilia sericata induce clotting of human plasma and whole blood, particularly by activating contact phase proteins factor XII and kininogen as well as factor IX, thereby providing kallikrein-bypassing and factor XIa-like activities, both in plasma and in isolated systems. In plasma samples deficient in contact phase proteins, MEP restored full clotting activity, whereas in plasma deficient in either factor VII, IX, X or II no effect was seen. The observed procoagulant/intrinsic pathway-like activity was mediated by (chymo-) trypsin-like proteases in total MEP, which were significantly blocked by C1-esterase inhibitor or other contact phase-specific protease inhibitors. No significant influence of MEP on platelet activation or fibrinolysis was noted. Together, MEP provides contact phase bypassing procoagulant activity and thereby induces blood clotting in the context of wound healing. Further characterisation of the active serine protease(s) may offer new perspectives for biosurgical treatment of chronic wounds.

The immediate and late effects of thyroid hormone (triiodothyronine) on murine coagulation gene transcription.

Thyroid dysfunction is associated with changes in coagulation. The aim of our study was to gain more insight into the role of thyroid hormone in coagulation control. C57Black/6J mice received a low-iodine diet and drinking water supplemented with perchlorate to suppress endogenous triiodothyronine (T3) and thyroxine (T4) production. Under these conditions, the impact of exogenous T3 on plasma coagulation, and hepatic and vessel-wall-associated coagulation gene transcription was studied in a short- (4 hours) and long-term (14 days) setting. Comparing euthyroid conditions (normal mice), with hypothyroidism (conditions of a shortage of thyroid hormone) and those with replacement by incremental doses of T3, dosages of 0 and 0.5 µg T3/mouse/day were selected to study the impact of T3 on coagulation gene transcription. Under these conditions, a single injection of T3 injection increased strongly hepatic transcript levels of the well-characterized T3-responsive genes deiodinase type 1 (Dio1) and Spot14 within 4 hours. This coincided with significantly reduced mRNA levels of Fgg, Serpinc1, Proc, Proz, and Serpin10, and the reduction of the latter three persisted upon daily treatment with T3 for 14 days. Prolonged T3 treatment induced a significant down-regulation in factor (F) 2, F9 and F10 transcript levels, while F11 and F12 levels increased. Activity levels in plasma largely paralleled these mRNA changes. Thbd transcript levels in the lung (vessel-wall-associated coagulation) were significantly up-regulated after a single T3 injection, and persisted upon prolonged T3 exposure. Two-week T3 administration also resulted in increased Vwf and Tfpi mRNA levels, whereas Tf levels decreased. These data showed that T3 has specific effects on coagulation, with Fgg, Serpinc1, Proc, Proz, Serpin10 and Thbd responding rapidly, making these likely direct thyroid hormone receptor targets. F2, F9, F10, F11, F12, Vwf, Tf and Tfpi are late responding genes and probably indirectly modulated by T3.

Dietary supplementation with dried chicory root triggers changes in the blood serum proteins engaged in the clotting process and the innate immune response in growing pigs.

The aim of the study was to characterize the systemic immune and metabolic alterations in the blood serum of growing pigs in response to a dietary supplementation with 4% of dried chicory roots. This was achieved by examining the influence of the experimental diet on serum protein changes especially these related with immunology and lipid metabolism. Serum proteins with the isoelectric point ranging from pH 3.0 to 10.0 were separated using high resolution two-dimensional electrophoresis. As a result, we found that experimental diet triggered significant changes in 37 protein spots. Of these, 14 were up-regulated, whereas 23 showed down-regulation. Of 37 significantly altered protein spots, 24 were successfully identified, representing 14 distinct gene products. Implementation of the dried chicory roots into the diet of growing pigs caused a significant down-regulation of apolipoprotein C-II complement component C6, C-reactive protein, CD14 antigen, C4b binding protein α and ß chains, and fibrinogen. Piglets fed experimental diet had similar IgA, IgG and IgM concentrations, although the level of IgM tended to be lower compared to the control group. It is concluded that diet supplemented with 4% of dried chicory root may exert anti-inflammatory properties and affect lipid metabolism in growing pigs.

Effects of high-dose phytoestrogens on circulating cellular microparticles and coagulation function in postmenopausal women.

BACKGROUND/PURPOSE: Estrogen in hormone replacement therapy causes homeostatic changes. However, little is known regarding the safety of high-dose phytoestrogen on coagulation and hematological parameters in healthy postmenopausal women. This study evaluated the effects of high-dose soy isoflavone (300 mg/day) on blood pressure, hematological parameters, and coagulation functions including circulating microparticles in healthy postmenopausal women. METHODS: The original study is a 2-year prospective, double-blind, placebo-controlled study. In total, 431 postmenopausal women (from 3 medical centers) were randomly assigned to receive either high-dose isoflavone or placebo for 2 years. At baseline, 6 months, 1 year, and 2 years after treatment, blood pressure, body weight, liver function tests, hematological parameters, and lipid profiles were measured. The 1(st) year blood specimens of 85 cases of 144 eligible participants (from one of the three centers) were analyzed as D-dimer, von Willebrand factor antigen, factor VII, plasminogen activator inhibitor type 1, and circulating cellular microparticles, including the measurement of monocyte, platelet, and endothelial microparticles. RESULTS: In the isoflavone group, after 1 year, the changes in liver function tests, hematological parameters, and coagulation tests were not different from those of the control. Triglyceride levels were significantly lower after 6 months of isoflavone treatment than the placebo group, but the difference did not persist after 1 year. Endothelial microparticles increased steadily in both groups during the 1-year period but the trend was not affected by treatment. CONCLUSION: The results of the present study indicate that high-dose isoflavone treatment (300 mg/day) does not cause hematological abnormalities or activate coagulation factors.

Aqueous extract from Brownea grandiceps flowers with effect on coagulation and fibrinolytic system.

ETHNOPHARMACOLOGICAL RELEVANCE: Brownea grandiceps flowers are used in Venezuelan folk medicine as anti-hemorrhagic in women with heavy menstrual blood loss (menorrhagia). However, prior to this study, there were no scientific investigations to support this fact, because the aqueous extract from Brownea grandiceps flowers had not been previously evaluated neither phytochemically nor biologically. The objective of this work was to evaluate in vitro the effects of aqueous extract from Brownea grandiceps flowers on the coagulation system and fibrinolysis. MATERIALS AND METHODS: An infusion of Brownea grandiceps flowers (160g) was performed; then, it was homogenized, centrifuged and lyophilized to obtain the aqueous extract, and this was called BGE. Subsequently, the extract was characterized on the one hand, phytochemically and on the other hand, biologically, employing prothrombin time (PT), partial thromboplastin time (PTT) and thrombin time (TT) to determine the effects on extrinsic, intrinsic and common coagulation pathways, respectively. In addition to that, the fibrinogenolytic and fibronectinase activity was evaluated by SDS-PAGE using Tris-Tricine system and analyzed by densitometric study utilizing ImageJ program. Also, by using specific chromogenic substrates for Factor Xa (FXa), thrombin, tissue plasminogen activator (t-PA), urokinase plasminogen activator (u-PA) and plasmin, it was assessed whether BGE exhibited some enzyme-like activity, and inhibitory activity of the afore mentioned enzymes. Fibrinolytic and antifibrinolytic activities were determined by a fibrin plate method. Data were analyzed by an nonparametric method. RESULTS: BGE presented tannins, saponins, glycosides, alkaloids, flavonoids, coumarins, and did not contain triterpenoids and steroids. Also, BGE at low concentrations (250-1250µg/mL) reduced the PT, while higher concentrations (15000-25000µg/mL) prolonged this time. However, BGE concentrations between 1250 and 25000µg/mL prolonged the PTT. Prolongation of PT and PTT was observed at high concentrations and was due to FXa inhibitor found in BGE and this effect could be strengthened by degradation of fibrinogen and fibronectin, which were also produced by BGE. Moreover, BGE did not clot fibrinogen or human plasma, and neither did it cleave the chromogenic substrates specific to FXa nor thrombin. These results suggest the pro-coagulant components could be acting on some factor of the extrinsic pathway, since only PT was shortened. Furthermore, BGE did not hydrolyze the chromogenic substrate specific to plasmin, t-PA and u-PA nor did it produce fibrin degradation. However, all BGE concentrations tested inhibited the plasmin activity in a dose-dependent manner. CONCLUSIONS: The outcomes of this study reveal the presence of fibrinogenolytic, fibronectinase and anti-FXa components in BGE, plus anti-plasmin compounds that could be acting as antifibrinolytic, thus delaying the fibrin degradation in pathophysiological processes, as it has been observed in women presenting with menorrhagia due to a high plasmin concentration. Where this anti-plasmin compound, along with pro-coagulant components also present in BGE, could be made responsible for reducing heavy menstrual bleeding in women, since a deficiency in one or more blood coagulation factors such as factor VII, V or X, is a potential cause of menorrhagia.

Aspalathin and nothofagin from rooibos (Aspalathus linearis) inhibit endothelial protein C receptor shedding in vitro and in vivo.

Aspalathin (Asp) and nothofagin (Not) are two major active dihydrochalcones found in green rooibos, which have been reported for their anti-oxidant activity. Increasing evidence has demonstrated that beyond its role in the activation of protein C, endothelial cell protein C receptor (EPCR) is also involved in vascular inflammation. EPCR activity is markedly changed by ectodomain cleavage and its release as the soluble EPCR. EPCR can be shed from the cell surface, which is mediated by tumor necrosis factor-α converting enzyme (TACE). However, little is known about the effects of Asp and Not on EPCR shedding. Our results demonstrated that Asp and Not induced potent inhibition of phorbol-12-myristate 13-acetate (PMA)-, tumor necrosis factor (TNF)-α-, interleukin (IL)-1ß, and cecal ligation and puncture (CLP)-induced EPCR shedding. Asp and Not also inhibited the expression and activity of PMA-induced TACE in endothelial cells. Asp and Not also suppressed CLP-induced protein C decrease in mice and thrombin generation in HUVECs. In addition, treatment with Asp and Not resulted in reduced PMA-stimulated phosphorylation of p38, extracellular regulated kinase (ERK) 1/2, and c-Jun N-terminal kinase (JNK). These results demonstrate the potential of Asp and Not as an anti-sEPCR shedding reagent against PMA and CLP-mediated EPCR shedding.

The Arg98Trp mutation in human VKORC1 causing VKCFD2 disrupts a di-arginine-based ER retention motif.

Vitamin K 2,3-epoxide reductase complex subunit 1 (VKORC1) is an enzyme localized to the endoplasmic reticulum (ER) membrane. VKORC1 catalyzes the reduction of vitamin K 2,3-epoxide to vitamin K and to vitamin K hydroquinone, the latter required by the enzyme γ-carboxylase for γ-carboxylation of all vitamin K-dependent (VKD) proteins. Until now, only 1 human VKORC1 mutation, p.Arg98Trp, is known to cause combined deficiency of VKD clotting factors type 2 (VKCFD2), a disease phenotype reported in 3 unrelated families. VKCFD2 patients suffer from spontaneous bleeding episodes because of decreased levels of γ-carboxylated VKD clotting factors. Daily supraphysiological vitamin K supplementation restores clotting for VKCFD2 patients and results in high serum levels of vitamin K 2,3-epoxide, suggesting that supplemented vitamin K is reduced in vivo. Although the p.Arg98Trp mutation results in reduced vitamin K 2,3-epoxide reductase activity, the molecular mechanism underlying this pathophysiology is unknown. Using a combination of in silico analysis and confocal microscopy, we demonstrate for the first time that VKORC1:p.Arg98Trp disrupts a di-arginine ER retention motif resulting in 20% ER colocalization only. As a consequence, VKORC1 exits the ER membrane by cellular quality control systems and results in the observed VKCFD2 phenotype.

Impact of stearic acid and oleic acid on hemostatic factors in the context of controlled diets consumed by healthy men.

The effects of stearic acid (STA) on cardiovascular disease risk beyond lipid and lipoprotein risk factors, including hemostasis, are unclear, particularly when compared with unsaturated fatty acids. The aim of the present study is to compare the effects of STA with those of oleic acid (OL) on markers of hemostasis. In a randomized crossover study, 50 men consumed six controlled diets for 5 weeks each (39% energy from fat, 15% energy from protein, 46% energy from carbohydrate (CHO)). Fat (8% energy) was replaced across diets by: STA, OL, CHO (control), trans fatty acids (TFAs), TFA/STA and 12:0-16:0 saturated fatty acids. Factor VIIc, plasminogen activator inhibitor-1 (PAI-1) and plasmin alpha-2-antiplasmin complex concentrations were not different between OL and STA (P>0.05). Compared with control, OL increased factor VIIc and PAI-1 (P≤0.05), whereas there were no differences with STA (P>0.05). STA and OL similarly affect markers of hemostasis in healthy men, within the context of a highly controlled diet.

Measurement and reversal of prophylactic and therapeutic peak levels of rivaroxaban: an in vitro study.

BACKGROUND: Rivaroxaban (Xarelto, Bayer HealthCare, Leverkusen, Germany) is a new oral anticoagulant drug. Anticoagulants may cause bleeding, thereby requiring reliable monitoring and efficient therapy. We investigated thromboelastometry versus routine coagulation tests to measure prophylactic and therapeutic concentrations of rivaroxaban and their reversal with prothrombin complex concentrate (PCC) and activated recombinant factor VII (rFVIIa) in vitro. METHODS: Rivaroxaban was solubilized, and PCC and rFVIIa were added in 2 concentrations to the rivaroxaban-spiked blood samples, and thromboelastometry and measurements were performed. RESULTS: Rivaroxaban increased tissue factor-activated clotting time (CT(ExTEM)) dose dependently. Activated partial prothrombin time (aPTT), prothrombin time ratio (PTR), and prothrombin time (PT) were changed significantly in both concentrations. Reversal with PCC in both dosages caused no significant change in the measured parameters. For prophylactic rivaroxaban dosage, rFVIIa changed the PT significantly but not CT(ExTEM), aPTT, and PTR. For therapeutic rivaroxaban dosage, the CT(ExTEM) was significantly reduced. The other parameters remained unaffected. CONCLUSIONS: Thromboelastometry can detect rivaroxaban effects. In vitro rFVIIa seems highly effective for reversal in contrast to PCC.

Is there an effect of folic acid supplementation on the coagulation factors and C-reactive protein concentrations in subjects with atherosclerosis risk factors?

INTRODUCTION: Folic acid (FA) may delay the formation of atherosclerotic lesions. Increased plasma levels of von Willebrand factor (VWF) are observed in cardiovascular disease, which leads to higher risk of thrombosis. Fibrinogen (Fb) is a well-documented risk factor of cardiovascular disease. The aim of this study was to analyze the effect of FA supplementation on the Fb, VWF and C-reactive protein (CRP) plasma concentrations in subjects with atherosclerosis risk factors. MATERIAL/METHODS: The study enrolled 124 Caucasian individuals (60 M, 64 F) with atherosclerosis risk factors--family history of premature ischaemic stroke, arterial hypertension, dyslipidaemia, overweight and obesity, cigarette smoking and low physical activity. The participants were asked to take FA in the low dose of 0.4 mg/24 h for three months. RESULTS: After FA supplementation a significant reduction of the VWF concentrations in females (76.6 vs 72.3%; p=0.028) and in males (75.5 vs 66.9%; p=0.001) was observed. Among women and men with dyslipidaemia concentrations of VWF decreased after FA supplementation (76.8% vs 69.6%; p=0.003 and 76.7% vs 67.8%; p=0.001 respectively). Among females and males with BMI ≥25 kg/m² concentrations of VWF decreased only in men (77.6% vs 66.5%; p=0.001). In female and male smokers supplementation of FA decreased VWF concentrations (82.5% vs 74.4%; p=0.012 and 76.6% vs 69.5%; p=0.036 respectively). DISCUSSION: The results of our study suggest that there is an effect of FA supplementation on VWF concentrations in subjects with atherosclerosis risk factors.