Coagulation Inhibitors Research Articles

Acclimatized Lowlanders Exhibit a Hypocoagulable Profile after a Passive Ascent at High Altitude.

Stauffer, Emeric, François Caton, Raphael Marlu, Aurélien Pichon, Landry Seyve, Michael Furian, Aymeric Paillisser, Florence Berquet, Jeremy De Abreu, Blandine Deschamps, Benoit Polack, Philippe Connes, Paul Robach, Stéphane Doutreleau, Julien V Brugniaux, Samuel Verges, and Benoit Champigneulle.Acclimatized lowlanders exhibit a hypocoagulable profile after a passive ascent at high altitude. High Alt Med Biol. 00:00-00, 2024. Background: Discordant results have been previously reported regarding the impact of high-altitude (HA) exposure on coagulation. We aimed to investigate changes in coagulation parameters in lowlanders exposed to HA for 14 days using a combination of dynamic coagulation assays and conventional in vitro tests. Material and Methods: We assessed coagulation in 10 lowlanders using whole-blood rotational thromboelastometry (ROTEM), thrombin generation assay (TGA) on poor-platelet plasma, and conventional coagulation tests. Tests were performed at low altitude (LA, 210 m) and at the end of a 14-day sojourn at HA, including passive ascents to 3,800 m for 6 days and then to 5,100 m for 8 days. Results: Conventional tests revealed significant changes in coagulation factors and inhibitors after HA exposure, although these changes remained within normal ranges. ROTEM assays demonstrated a delayed clot initiation in EXTEM/FIBTEM, without any alteration in clot firmness, in HA versus LA (p < 0.01). TGA changes showed an increase in time to peak (p < 0.01), a decrease in endogenous thrombin potential (p < 0.05), and a decrease in thrombin peak (p < 0.001). Conclusions: We found no evidence of hypercoagulability in lowlanders after a 14-day sojourn at HA. In contrast, dynamic coagulation assays (ROTEM and TGA) revealed a hypocoagulable pattern.

Validation of current commercially-available devices to thaw pooled, solvent/detergent-treated human plasma.

Proper thawing procedures are required to preserve the quality of human fresh frozen plasma (FFP). octaplasLG (Octapharma AG, Switzerland) is a frozen solution of solvent/detergent (S/D)-treated human plasma, produced to improve pathogen safety. This study aimed to validate the S/D plasma thawing process using the latest-generation of commercially-available thawing devices and to determine S/D plasma quality after thawing. Thawing of S/D plasma units was investigated using a microwave oven (Transfusio-therm 3000) and dry tempering systems (SAHARA 4 and Plasmatherm V). Times to defrost plasma and reach 30°C product temperature, using the 37°C thawing programmes, were defined for all devices. Thawed S/D plasma units were tested against product release parameters, as well as for hemostatic capacity tested indirectly via global coagulation parameters, coagulation factors, protease inhibitors and markers of activated coagulation. The fastest thawing was observed using the microwave oven; S/D plasma units were defrosted after 2-3 min. All S/D plasma units thawed by the different devices using optimised thawing conditions were clear and free of solid and gelatinous particles, indicating no local overheating or protein denaturation. Coagulation factor and inhibitor activities and hemostatic capacity of S/D plasma were comparable when thawed by the three different devices. With each device, all product parameters were within product release specification levels after thawing. S/D plasma can be thawed using the Transfusio-therm 3000, SAHARA 4 or Plasmatherm V thawing devices using the optimised settings defined for this plasma product, with no negative influence on plasma quality.

The Basic Principles of Pathophysiology of Venous Thrombosis.

The past few decades have brought tremendous insight into the molecular and pathophysiological mechanisms responsible for thrombus generation. For a clinician, it is usually sufficient to explain the incident of deep vein thrombosis (DVT) with provoking factors such as trauma with vascular injury, immobilization, hormonal factors, or inherited or acquired coagulation defects. About half of DVTs are, however, lacking such triggers and are called unprovoked. Venous stasis and hypoxia at the valve sinus level may start a chain of reactions. The concept of immunothrombosis has added a new dimension to the old etiological triad of venous stasis, vessel wall injury, and changes in blood components. This is particularly important in COVID-19, where hyperinflammation, cytokines, and neutrophil extracellular traps are associated with the formation of microthrombi in the lungs. To better understand the mechanisms behind DVT and reach beyond the above-mentioned simplifications, animal models and clinical epidemiological studies have brought insight into the complex interplay between leukocytes, platelets, endothelium, cytokines, complements, and coagulation factors and inhibitors. These pathways and the interplay will be reviewed here, as well as the roles of cancer, anticancer drugs, and congenital thrombophilic defects on the molecular level in hypercoagulability and venous thromboembolism.

Relationship between Natural Coagulation Inhibitor and Obstetrics History in Predicting Thromboembolic Events during Pregnancy

Background: There is a low level of information on natural coagulation inhibitors in this environment and whether the early detection of its deficiencies could serve as a risk assessment tool for thromboembolic events in pregnancy. This study aims to determine the relationship between natural coagulation inhibitors and obstetrics history in predicting thromboembolic events during pregnancy. Methods: The study was a comparative cross-sectional hospital-based study conducted among one hundred and fifty pregnant women and age-matched healthy non-pregnant control. Obstetrics history was obtained via questionnaire and other information was extracted from case notes. Blood specimens were obtained for laboratory assessment of natural coagulation inhibitors (Protein C, S, and antithrombin III) at various trimesters of pregnancy. Data were analyzed using SPSS version 23. Results: All NCIs decreased across the three trimesters of pregnancy but only the mean protein S and antithrombin III decreased with statistical significance (p = 0.001). Protein C, S, and antithrombin III did not show a statistically significant association when correlated with obstetrics histories. Conclusion: Although this study demonstrated a progressive decrease in the levels of NCIs across various trimesters of pregnancy, the use of NCIs as predictive tools for thromboembolic events in women with past bad obstetrics histories was not established but rather for risk assessment during pregnancy regardless of past obstetrics history.

Portal Vein Thrombosi (PVT) Secondary to Deficiency C Protein in a Young Male

Background Inherited defects of the natural coagulation inhibitors predispose patients to thrombosis. These disorders have similar clinical presentations with a strong family of thrombosis, episodes of recurrent venous thromboembolism, beginning in early adulthood. We report a case of portal vein thrombosis (VPT) secondary to hereditary protein C deficiency in a young male. Case History A 39-year-old male was admitted to the hospital for abdominal pain. Laboratory tests revealed levels of alanine and aspartate aminotransferases increased and levels of lipase and amylase normal, ruling out any possibility of pancreatitis. Abdominal CT scan indicated thrombosis of the portal vein and multiple celiac lymph nodes. To exclude occult malignancy PET/CT scan was conducted. Results from viral profiles and tumor markers were negative. Thrombophilic screening was negative except for low levels of protein C (PC) antigen (28% with n.r. 70-140%). Therefore, insufficient PC came out to be the primary cause of PVT. The patient was prescribed anticoagulant therapy with fondaparinux 7,5 mg/die and then warfarin for a long period to target an INR range of 2-3. Discussion Inherited PC deficiency is rare in PVT. Its identification is important for treatment of PVT, with better outcomes associated with early anticoagulant medication intervention.

Portal Vein Thrombosi (PVT) Secondary to Deficiency C Protein in a Young Male

Background Inherited defects of the natural coagulation inhibitors predispose patients to thrombosis. These disorders have similar clinical presentations with a strong family of thrombosis, episodes of recurrent venous thromboembolism, beginning in early adulthood. We report a case of portal vein thrombosis (VPT) secondary to hereditary protein C deficiency in a young male. Case History A 39-year-old male was admitted to the hospital for abdominal pain. Laboratory tests revealed levels of alanine and aspartate aminotransferases increased and levels of lipase and amylase normal, ruling out any possibility of pancreatitis. Abdominal CT scan indicated thrombosis of the portal vein and multiple celiac lymph nodes. To exclude occult malignancy PET/CT scan was conducted. Results from viral profiles and tumor markers were negative. Thrombophilic screening was negative except for low levels of protein C (PC) antigen (28% with n.r. 70-140%). Therefore, insufficient PC came out to be the primary cause of PVT. The patient was prescribed anticoagulant therapy with fondaparinux 7,5 mg/die and then warfarin for a long period to target an INR range of 2-3. Discussion Inherited PC deficiency is rare in PVT. Its identification is important for treatment of PVT, with better outcomes associated with early anticoagulant medication intervention

Production of physiological amounts of hemostatic proteins by human donor livers during ex situ long-term normothermic machine perfusion for up to 7 days

BackgroundNormothermic machine perfusion (NMP) is used for preservation and assessment of human donor livers prior to transplantation. During NMP, the liver is metabolically active, which allows detailed studies on the physiology of human livers. ObjectivesTo study the production of hemostatic proteins in human donor livers during NMP for up to 7 days. MethodsIn this observational study, 9 livers underwent NMP for up to 7 days with a heparinized perfusate based on red blood cells and colloids using a modified Liver Assist device (XVIVO). Perfusate samples were collected before NMP and daily thereafter for measurement of antigen and activity levels of a comprehensive panel of hemostatic proteins after heparin neutralization. ResultsWithin 1 day, perfusate samples displayed the potential for coagulation activation as evidenced by international normalized ratio and activated partial thromboplastin assays. This was accompanied by detection of substantial quantities of functionally active coagulation proteins and inhibitors, although the specific activity of many proteins was decreased, compared with that in normal plasma. Perfusate levels of hemostatic proteins increased in the first days, reaching a stable level after 3 to 4 days of perfusion. ConclusionDuring long-term NMP of human livers, functionally active hemostatic proteins are released into the perfusate in substantial quantities, but some proteins appear to have decreased functional properties compared with proteins in normal human plasma. We propose that NMP may be used as a platform to test efficacy of drugs that stimulate or inhibit the production of coagulation factors or to test liver-mediated clearance of prohemostatic protein therapeutics.

Tyrosine Kinase-2, Angiopoietin-2, and Thrombomodulin Axes in the Late-Onset Fetal Growth Restriction: A Prospective Cohort Study

OBJECTIVE: Investigating the interaction among three interconnected proteins, namely receptor Tyrosine Kinase-2 (Tie-2), the vascular remodeling cytokine Angiopoietin-2 (Ang-2), and the coagulation inhibitor Thrombomodulin (TM), may offer fresh insights into the multifactorial origins of late-onset fetal growth restriction (LFGR). STUDY DESIGN: In this prospective cohort study, we assessed the maternal serum concentrations of Tie-2, Ang-2, and TM in pregnancies that developed LFGR (n=30) and a control group (n=59) within the gestational weeks of 32-39 gestational weeks at Trakya University Hospital (January 2021-December 2021). Concentrations were quantified using ELISA, and data analysis was conducted using the SPSS 22.0 Windows software package. RESULTS: The 75th percentile concentrations of these proteins were significantly lower in cases of LFGR. Among heavy smokers, the risk of LFGR increased by 2.37-fold. A significant correlation was observed between these proteins in both LFGR and healthy pregnancies. However, the sensitivity and specificity of these proteins within the Tie-2, Ang-2, and TM axes were 51%, 56%, 51%, and 45%, 52%, and 50%, respectively. When we examined cases where all three proteins exhibited a consistent trend, LFGRs accounted for 23.33% with reduced levels and 30% with elevated levels, whereas this pattern was observed in 40.67% with reduced levels and 42.37% with elevated levels in healthy pregnancies. CONCLUSION: Although our study underscores the significance of the intricate interactions between Tie-2, Ang-2, and TM proteins in LFGR pregnancies, it is evident that a more comprehensive investigation is required to make meaningful contributions to the clinical applicability of this subject.

FXa-mediated PAR-2 promotes the efficacy of immunotherapy for hepatocellular carcinoma through immune escape and anoikis resistance by inducing PD-L1 transcription

BackgroundThe high metastasis rate is one of the main reasons for the poor prognosis of patients with hepatocellular carcinoma (HCC). Coagulation factor Xa (FXa) and its receptor proteinase-activated receptor-2 (PAR-2)...

Innovative approaches to assessing risk factors, diagnostics and treatment of neonatal thrombosis

Compared to children of other ages, neonates especially seriously ill and premature subjects comprise a high thrombotic risk group. A decline in the incidence of neonatal thrombosis may be accounted for by improved treatment of severe conditions in newborns and increased survival of premature infants. Neonatal and adult hemostasis exhibit distinct physiological features: difference in concentration, synthesis rate of blood coagulation factors, metabolic rate, thrombin and plasmin levels. At the same time, neonatal threshold values for natural blood coagulation inhibitors (protein C, protein S, antithrombin, heparin cofactor II) and vitamin K-dependent coagulation factors (FII, FVII, FIX, FX) are quite low, whereas that of FVIII and von Willebrand factor exceeds those found in adults. Thus, newborns have lower plasma fibrinolytic activity. The main risk factors for developing thrombotic complications are as follows: central venous catheters, altered body fluid volume, liver disease, as well as sepsis and inflammatory processes particularly COVID-19. The significance of congenital and acquired maternal and neonatal thrombophilia may pose an additional risk factor for thrombotic complications. Low-molecular weight heparins are the first-choice drugs in treatment and prevention of neonatal thrombosis.

Acquired haemophilia A in a patient with pemphigus vulgaris: A case report on a rare coexistence

Acquired haemophilia A is a rare disease, occurs in patients with no family history of haemophilia. In contrast to congenital haemophilia, acquired haemophilia A is mediated by antibodies causing inactivation or increased clearance of factor VIII leading to abnormal bleeding manifestation. It can be associated with many underlying conditions including autoimmune diseases. Herein we report a case of a 64 year old male with underlying pemphigus vulgaris presented with a psoas haematoma. Coagulation profile, factor assay and inhibitor assay were confirmed the diagnosis of acquired haemophilia A. The patient was not responding to first line therapy, later started on rituximab and achieved remission successfully. This is a rare coexistence of acquired haemophilia A with pemphigus vulgaris with few reported cases worldwide. We believe this case report highlights the importance of suspecting an acquired bleeding disorder in a patient with underlying autoimmune disease, present with a recent onset of abnormal bleeding. Even though the bleeding in acquired haemophilia A could be life threatening, early intervention with haemostatic agents and eradication therapy would be lifesaving.

Ramadan intermittent fasting is associated with improved anticoagulant activity among healthy people: a case–control study

Data on the pathophysiological mechanisms of hemostatic alterations in the thrombotic events that occur during Ramadan intermittent fasting (RIF), particularly in the natural coagulation inhibitors, are very limited. Thus, our objective was to evaluate the effect of RIF on the natural anticoagulants level, antithrombin, protein C, and total and free protein S (PS) in healthy participants. Participants were divided into two groups. Group I consisted of 29 healthy fasting participants whose blood samples were taken after 20 days of fasting. Group II included 40 healthy non-fasting participants whose blood samples were taken 2–4 weeks before the month of Ramadan. Coagulation screening tests including prothrombin time (PT), activated partial thromboplastin time (APTT) and plasma fibrinogen level, natural anticoagulants; antithrombin, protein C, free and total PS and C4 binding protein (C4BP) levels were evaluated in the two groups. High levels of total and free PS without change in antithrombin, protein C, and C4BP levels were noted in the fasting group as compared with non-fasting ones (p < 0.05). PT and APTT showed no difference between the two groups. However, the fibrinogen level was higher in the fasting group. In conclusion, RIF was found to be associated with improved anticoagulant activity in healthy participants, which may provide temporal physiological protection against the development of thrombosis in healthy fasting people.

Effect of intraoperative blood transfusion during maternal cesarean section on serum electrolytes and inflammatory response plus cellular immune response: A retrospective study.

Analyzing the effect of intraoperative autotransfusion on serum electrolytes, inflammatory response and cellular immune response in puerperae undergoing cesarean section. This study is a retrospective study of 60 women who underwent cesarean section in our hospital from January 2022 to January 2023. The subjects were divided into 2 groups according to the blood transfusion mode of the patients. The differences in blood transfusion volume, blood transfusion volume, serum electrolyte, inflammatory response, cellular immune function, coagulation function and prognosis were compared between the 2 groups. The intraoperative blood transfusion volume, postoperative feeding time, the activity time since getting out of bed, the time of physical recovery and hospital stay in the observation group were lower compared to those of the control group, but the intraoperative crystal infusion volume and the colloid infusion volume in the observation group were higher compared to those of the control group (P < .05). Ca2+ concentrations of the observation group and the control group were lower compared with those of their same groups before surgery (P < .05), however, there were no statistically significant differences in the comparison of the Ca2+ concentrations between the observation group and the control group (P > .05). At 1d postoperatively, IL-1β, IL-6 and granulocyte-macrophage colony-stimulating factor (GM-CSF) were all higher (P < .05) and CD3+, CD4+ and CD4+/CD8+ were all lower (P < .05) in the observation group and the control group compared with those of their same groups before surgery. The IL-1 β, IL-6, and GM-CSF of the observation group were decreased compared to those of the control group (P < .05) and CD3+, CD4+, CD4+/CD8+ of the observation group were elevated compared to those of the control group (P < .05). Both autotransfusion and allogeneic blood transfusions during maternal cesarean section can attenuate the inflammatory response and have no significant inhibition of coagulation, and autotransfusion have less effect on the cellular immune response, are more effective in attenuating the inflammatory response, and significantly improve prognosis, although changes in Ca2+ concentration after transfusion require attention.

Post-operative epidural haematoma as complication of overconsumption of dried fruit in lumbar spinal surgery: a case report and review of the literature

PurposeMebos, a traditional South Africa confection consisting of dried, pulped, and sugared apricots, is rich in fibre and vitamins, but also contains salicylic acid, flavonoids, and citric acid. We report a case of postoperative surgical site bleeding in a healthy patient who consumed approximately 2 kg of mebos per day prior to his elective spinal surgery.MethodsThe clinical course of a previously healthy 54-year-old male patient with cauda equina syndrome secondary to lumbar spinal stenosis who underwent surgical intervention with subsequent bleeding into the surgical site is discussed. The cause was investigated through biochemical analysis, thromboelastometry (ROTEM®) and mass and absorption spectrometry were applied to assess flavonoid, citric acid, and salicylic acid content.ResultsROTEM® revealed an abnormal clotting profile with an increased clot forming time, suggesting intrinsic coagulopathy. Mass and absorption spectrometry revealed a high total flavonoid content as well as citric acid concentration in the mebos. Salicylic acid was at detection limits of the instrument.ConclusionResults highlighted the effect of flavonoids and citric acid and therefore explain the abnormal clotting profile in this patient. Inhibition of coagulation prior to elective surgery is a known contraindication and may pose great risks in spinal surgery. In the present report, we demonstrated an association between inhibition of coagulation and an excess of the flavonoids content and citric acid concentration in mebos consumed in the days prior to elective spinal surgery.

Alkaloids from Siparuna (Siparunaceae) are predicted as the inhibitors of proteolysis and plasma coagulation caused by snake venom and potentially counteract phospholipase A2 activity of Bothrops jararaca

Ethnopharmacological relevanceSnakebite envenomation (SBE) is the world's most lethal neglected tropical disease. Bothrops jararaca is the species that causes the greatest number of SBEs in the South and Southeastern of Brazil. The main symptoms are local (inflammation, edema, hemorrhage, and myonecrosis) and systemic (hemorrhage, hemostatic alterations with consumptive coagulopathy, and death) effects. Species of the genus Siparuna, Siparunaceae, are used in folk and traditional medicine to treat SBE. However, limited information is available concerning Brazilian Siparuna species against SBE. Aim of the studyTo investigate the correlation between the compounds present in the extracts of five Siparuna species as potential agents against proteolytic activity, plasma coagulation, and phospholipase A2 (PLA2) activity caused by B. jararaca venom, using data obtained by UHPLC-MS/MS, biological activity, and multivariate statistics. Materials and methodsThe ethanol extracts from leaves of S. ficoides, S. decipiens, S. glycycarpa, S. reginae, and S. cymosa were fractionated by liquid-liquid extraction using different solvents of increasing polarity (hexane, dichloromethane, ethyl acetate, and n-butanol), affording their respective extracts, totaling 25 samples that were assayed through in vitro plasma coagulation and proteolytic activity assays. Moreover, the extracts were analyzed by UHPLC-MS/MS, using electrospray ionization (ESI) and atmospheric-pressure chemical ionization (APCI) in negative and positive ionization modes. The data was processed in MZmine v. 2.53 and evaluated by multivariate statistical tests (PLS) using the software UnscramblerX v. 10.4. These data were also used to build molecular networks (GNPS), and some ions of interest could be annotated using the library of molecules on the GNPS platform. ResultsA total of 19 extracts inhibited B. jararaca-induced plasma coagulation, with emphasis on S. cymosa and S. reginae (800 s). The inhibition of the proteolytic activity was also promising, ranging from 16% (S. glycycarpa) to 99% (S. cymosa, S. decipiens, and S. reginae). In addition, most extracts from S. cymosa and S. reginae inhibited 70–90% of PLA2 activity. Based on data from positive mode APCI analyses, it was possible to obtain a statistic model with reliable predictive capacity which exhibited an average R2 of 0.95 and a Q2 of 0.88, indicating a robust fit. This process revealed five ions, identified as the alkaloids: coclaurine (1), stepholidine (2) O-methylisopiline (3), nornantenine (4) and laurolitsine (5). This is the first study to evidence the potential antivenom of alkaloids from Siparuna species. ConclusionsAltogether, our results give support to the popular use of Siparuna extracts in SBE accidents, suggesting their potential as an alternative or complementary strategy against envenoming by B. jararaca venom. The predicted ions in the chemometric analysis for the assayed activities can also be correlated with the blocking activity and encourage the continuation of this study for possible isolation and testing of individual compounds on the used models.

Comparative genomics of two Asian medicinal leeches Hirudo nipponia and Hirudo tianjinensis: With emphasis on antithrombotic genes and their corresponding proteins

Leeches secrete various biologically active substances which have important medical and pharmaceutical values in antithrombotic treatments. Here, we provide a high quality genome of two Asian medicinal leeches Hirudo nipponia and Hirudo tianjinensis, based on which, we identified 22 antithrombotic gene families, including fourteen coagulation inhibitors, four platelet aggregation inhibitors, three fibrinolysis enhancers, and one tissue penetration enhancer. The total numbers of antithrombotic genes were similar between H. nipponia (N = 86) and H. tianjinensis (N = 83). Molecular evolution analysis showed that no significant differences were detected between the two species in any of the three selection indices (dN, dS, and dN/dS), nor in the number of sites under positive/purifying selection. RNA-Seq based gene expression analysis showed that the overall expression patterns of the antithrombotic gene families were not significantly deviated between the two species. Our results indicated that there were rather close similarities between the two leeches on genomic characteristics, especially for the molecular evolution and expression of antithrombotic genes. Our study provides the most comprehensive collection of antithrombotic biomacromolecules from the two Asian medicinal leeches to date. These results will greatly facilitate the research and application of leech derivatives for medical and pharmaceutical purposes of thrombosis.

Correlation between blood international normalised ratio (INR) value and saliva prothrombin concentration in patients under warfarin therapy: An observational analytics study

Introduction: Oromaxillofacial surgery has a bleeding risk complication. Increasing bleeding risk can be caused by the use of blood clotting inhibitors, including warfarin. Warfarin is an anticoagulant that works by inhibiting coagulation factors in the cascade. International normalised ratio (INR) indicates warfarin monitoring and bleeding risk during surgical procedures. INR examination currently uses blood plasma. This research analyses the correlation between blood INR value and salivary prothrombin concentration. Methods: This research was an analytical observational with a correlational design on 19 samples examined using a human prothrombin reagent from Elabscience. The samples used were blood and saliva, and then ELISA tests were carried out on them. Data results were analysed with linear regression and correlation tests. Results: In this study, 19 samples were collected from 6 male and 13 female subjects. The average value of salivary prothrombin concentration in this study was 227.63 (ng/ml), and the blood INR value was 1.85. The normality test result showed that the data distribution was normal; therefore, the correlation and simple linear regression tests can be conducted. The correlation and regression tests showed a positive correlation between blood INR value and salivary prothrombin concentration with a correlation coefficient of r = 0.81 (p &lt; 0.001). Conclusion: There is a positive relationship between blood INR value and salivary prothrombin concentration in oromaxillofacial patients under warfarin therapy.

Platelet activity, coagulation, and fibrinolysis in long-term users of anabolic-androgenic steroids compared to strength-trained athletes

IntroductionUse of anabolic-androgenic steroids (AAS) is associated with adverse cardiovascular (CV) effects, including potential prothrombotic effects. This study aimed to assess platelet activation and aggregation, coagulation, and fibrinolysis, in long-term AAS users compared to non-using strength-trained athletes. Materials and methodsThirty-seven strength-trained men using AAS were compared to seventeen non-using professional strength-trained athletes at similar age (median 33 years). AAS use was verified by blood and urine analyses. Platelet Function Analyzer 100 (PFA-100) and whole blood impedance aggregometry with thrombin, arachidonic acid, and ADP as agonists, were performed to evaluate platelet aggregation. ELISA methods were used for markers of platelet activation. Fibrinogen, D-dimer, the coagulation inhibitors protein S and C activity, and antithrombin were measured by routine. Fibrinolysis was evaluated by Plasminogen Activator Inhibitor-1 (PAI-1) activity. ResultsThere were no significant differences in platelet aggregation between the two groups. Von Willebrand factor was lower among the AAS users (p < 0.01), and P-Selectin was slightly higher (p = 0.05), whereas CD40 Ligand, β-thromboglobulin, and thrombospondin did not differ significantly. No differences were found in the assessed coagulation inhibitors. Higher D-dimer levels (p < 0.01) and lower PAI-1 activity (p < 0.01) were found among the AAS users. ConclusionsThe investigated long-term users of AAS did not exhibit elevated platelet activity compared to strength-trained non-using athletes. However, AAS use was associated with higher D-dimer levels and lower PAI-1 activity. These findings suggest that any prothrombotic effect of long-term AAS use may predominantly involve other aspects of the hemostatic system than blood platelets.

New method to differentiate between lupus anticoagulants, progressive coagulation inhibitors and coagulation factor deficiencies in the mixing tests.

Mixing tests in activated partial thromboplastin time (APTT) are used for the differentiation between lupus anticoagulants (LA), coagulation inhibitors, and factor deficient samples with APTT prolongation. However, the indexes for the differentiation have not been established. The present study aimed to develop new mixing test indexes for the differentiation. Twenty-six LA-positive, 8 progressive coagulation factor VIII inhibitor, and 35 coagulation deficient samples were employed. APTT were measured for normal plasma, patient plasma, and mixing plasma prepared at a ratio of 1:1 proportion in both without incubation and 2 h-incubation. New two parameters named as ALD50 and mixture plasma-patient plasma after Warming change rate Subtraction (WaS) calculated from the clotting times of normal, 1:1 mixing and patient samples with/without 2 h-incubation were established. In the samples with WaS result of <10.2%, ALD50 of ≥87.8%, and < 87.8% were defined as LA and coagulation factor deficiency, respectively, and WaS of ≥10.2% defined progressive coagulation factor inhibitors. Sensitivity and specificity to LA were 80.8% and 93.0% for ALD50, and sensitivity and specificity to progressive coagulation factor inhibitor were 100.0% and 100.0% for WaS, respectively. The agreement between sample classification and WaS-ALD50 was 88.4% (61/69). ALD50 and WaS showed acceptable sensitivity and specificity to LA and progressive coagulation factor inhibitor, respectively. These indexes would be useful for the differentiation between LA, factor deficiency, and progressive coagulation factor inhibitor in the mixing tests.

Changes in Internal Structure and Dynamics upon Binding Stabilise the Nematode Anticoagulant NAPc2.

Abnormal blood coagulation is a major health problem and natural anticoagulants from blood-feeding organisms have been investigated as novel therapeutics. NAPc2, a potent nematode-derived inhibitor of coagulation, has an unusual mode of action that requires coagulation factor Xa but does not inhibit it. Molecular dynamics simulations of NAPc2 and factor Xa were generated to better understand NAPc2. The simulations suggest that parts of NAPc2 become more rigid upon binding factor Xa and reveal that two highly conserved residues form an internal salt bridge that stabilises the bound conformation. Clotting time assays with mutants confirmed the utility of the salt bridge and suggested that it is a conserved mechanism for stabilising the bound conformation of secondary structure-poor protease inhibitors.