Antithrombin III supplementation during neonatal and pediatric extracorporeal membrane oxygenation.

BACKGROUND: Bleeding and thrombosis are common extracorporeal membrane oxygenation (ECMO) complications associated with increased mortality. Heparin is the most commonly used ECMO anticoagulant, employed in 94% of cases. Reduced antithrombin III (AT3) levels could decrease heparin effectiveness. Neonates have inherently lower levels of AT3 than adults, and pediatric patients on ECMO can develop AT3 deficiency. One potential approach for patients on ECMO with AT3 deficiency is exogenous AT3 supplementation. However, there is conflicting data concerning the use of AT3 for pediatric and neonatal patients on ECMO. METHODS: We analyzed the Bleeding and Thrombosis during ECMO database of 514 neonatal and pediatric patients on ECMO. We constructed daily regression models to determine the association between AT3 supplementation and rates of bleeding and thrombosis. Given the physiological differences between pediatric patients and neonates, we constructed separate models for each. RESULTS: AT3 administration was associated with increased rates of daily bleeding among pediatric (adjusted odds ratio [aOR] 1.59, p < 0.01) and neonatal (aOR 1.37, p = 0.04) patients. AT3 supplementation did not reduce the rate of thrombosis for either pediatric or neonatal patients. CONCLUSION: AT3 administration was associated with increased rates of daily bleeding, a hypothesized potential complication of AT3 supplementation. In addition, AT3 supplementation did not result in lower rates of thrombosis. We recommend clinicians utilize caution when considering supplementing patients on ECMO with exogenous AT3.

Antithrombin supplementation for prevention of vascular thrombosis after pediatric liver transplantation.

AIMS: After liver transplantation (LT), synthesis of coagulation factors by the graft recovers faster for pro thrombotic than anti thrombotic factors, resulting in a potential pro thrombotic imbalance. We studied the thrombotic and hemorrhagic complications in our pediatric LT series, providing supplementation of fresh frozen plasma (FFP) and/or antithrombin (AT) in the prophylactic antithrombotic regimen. METHODS: This was a retrospective observational single center study. All isolated pediatric LTs performed between 1/11/2009 and 31/12/2019 (n = 181) were included. Postoperatively, in addition to low molecular weight heparin, 22 patients (12%) received FFP (10 ml/kg twice daily for 10 days), 27 patients (15%) were given FFP (reduced duration) and AT (50-100 IU/kg/day if AT activity remained <70%), and 132 (73%) received AT only. Complications, outcome, and coagulation profiles in postoperative days 0-10 were analyzed. RESULTS: In all three treatment groups, AT activity normalized by day 4 while prothrombin remained <70% of normal until day 9. Hepatic artery thrombosis (HAT), portal vein thrombosis (PVT), and hemorrhagic complications occurred in 2.8%, 3.3%, and 3.9% of LTs. One- and 5-year patient and graft survival were 88% (±2.4% Standard Error) and 84% (±2.5%), and 86% (±2.6%) and 84% (±2.7%), respectively, without difference between groups. HAT were associated with low AT on days 0 and 1, and PVT with low AT on day 0. CONCLUSIONS: Low antithrombin activity after LT was associated with postoperative thromboses. FFP and/or AT supplementation allowed early normalization of AT activity, while thrombotic or hemorrhagic complications were rare, suggesting efficient and safe management of post-LT coagulopathy.

Pravastatin, proton-pump inhibitors, metformin, micronutrients, and biologics: new horizons for the prevention or treatment of preeclampsia.

There has been increasing research momentum to identify new therapeutic agents for the prevention or treatment of preeclampsia, drugs that can affect the underlying disease pathophysiology. Molecular targets of candidate treatments include oxidative stress, antiangiogenic factors, and the angiotensin, nitric oxide, and proinflammatory pathways. The proposed treatments undergoing preclinical and clinical trial evaluation are thought to act on placental or endothelial disease or both. Most have adopted the pragmatic strategy of repurposing drugs. Of all the therapeutic agents proposed, pravastatin has received the most interest. There are preclinical studies showing that it has pleiotropic actions that favorably impact on multiple molecular targets and can resolve a preeclampsia phenotype in many animal models. An early phase clinical trial suggests that it may have therapeutic activity. Several large prevention trials are planned or ongoing and, when completed, could definitively address whether pravastatin can prevent preeclampsia. Proton-pump inhibitors, metformin, and sulfasalazine are other drugs with preclinical evidence of multiple molecular actions that could resolve the pathophysiology of preeclampsia. These agents are also currently being evaluated in clinical trials. There have been many recent preclinical studies identifying the potential of numerous natural compounds to treat preeclampsia, such as plant extracts and micronutrients that have potent anti-inflammatory or antioxidant activity. Recent preclinical studies have also proposed novel molecular-targeted strategies, such as monoclonal antibodies targeting tumor necrosis factor alpha, placental growth factor, and short interfering RNA technology, to silence the gene expression of soluble fms-like tyrosine kinase-1 or angiotensinogen. Other treatment approaches that have transitioned to human trials (ranging from single-arm to phase III trials that have been completed or are ongoing) include folic acid, nitric oxide donors (such as L-arginine), recombinant antithrombin III, digoxin immune antigen-binding fragment, and melatonin. There have been case series showing the removal of circulating soluble fms-like tyrosine kinase-1 may help stabilize the disease and prolong pregnancy. Interestingly, there are case reports suggesting that monoclonal antibody eculizumab (complement inhibitor) may have therapeutic potential. If new agents are discovered that are proven to be effective in preventing or treating preeclampsia, the potential to improve global maternal and perinatal health will be significant.

Venous thromboembolism incidence and risk factors in adults with acute lymphoblastic leukemia treated with and without pegylated E. coli asparaginase-containing regimens.

PURPOSE: Asparaginases, key agents in treatment of acute lymphoblastic leukemia (ALL), are associated with venous thromboembolism (VTE). While risks of short-acting asparaginase-related VTE is well-known, we studied VTE incidence and risk factors in adult ALL patients treated with and without long-acting pegylated asparaginase (PegA). METHODS: Single-center, retrospective analysis of 89 ALL patients treated with (n = 61) or without (n = 28) PegA at Greenebaum Comprehensive Cancer Center. Reviewed patient and disease characteristics, treatment, and VTE incidence. RESULTS: VTE during treatment occurred in 31 patients (35%), and was associated with PegA (p = 0.001) and Philadelphia chromosome negativity (p = 0.002). Among PegA recipients, VTE was associated with a significantly higher mean body mass index (BMI) of 31.3 kg/m2 (p = 0.037), and was more common with pre-T/T cell compared to pre-B/B cell ALL (68.2% vs. 33.3%, p = 0.009). Antithrombin-III (ATIII) levels were measured for 26 patients; 16 (61.5%) were < 50%. Of those, 8 (50%) experienced VTE, while 3 of 10 (30%) patients with ATIII levels ≥ 50% experienced VTE. VTE occurred in 7 of 13 (54%) of patients who received ATIII repletion. There was a trend toward a higher incidence of VTE in the PegA group among patients with non-O compared to O blood type (55.9% vs. 33.3%, p = 0.079) as well as those with a higher hemoglobin at diagnosis (9.3 vs 8.1 g/dL, p = 0.056). CONCLUSION: This study confirms PegA as a risk factor for VTE in patients with ALL. Risk factors among those receiving PegA include higher BMI and pre-T/T cell ALL. ATIII repletion was not shown to be protective against VTE. There was a higher incidence of VTE in patients who received PegA with non-O compared to O blood type, but the precise correlation is uncertain.

Blood Coagulation Changes With or Without Direct Oral Anticoagulant Therapy Following Transcatheter Aortic Valve Implantation.

Thromboembolic events remain clinically unresolved after transcatheter aortic valve implantation (TAVI). The use of direct oral anticoagulant (DOAC) to reduce thrombosis associated with TAVI remains controversial. This study aimed at investigating the periprocedural change in blood coagulation and thrombolysis parameters in 199 patients undergoing transfemoral TAVI. Prothrombin activation fragment 1 + 2 (F1 + 2), thrombin-antithrombin complex (TAT), soluble fibrin monomer complex (SFMC), and fibrin/fibrinogen degradation product (FDP) levels were measured before and 1 hour after TAVI and 1, 2, and 7 days postoperatively. Of the 199 patients, 49 were treated with DOAC (apixaban in 32, edoxaban in 10, and rivaroxaban in 7). The F1 + 2 and TAT levels immediately increased 1 hour after TAVI and then gradually decreased in both groups. The SFMC level also significantly increased with a peak on day 1. The FDP level gradually increased, peaking on day 2. The values of F1 + 2, TAT, SFMC, and FDP in patients who used DOAC were significantly lower than those who did not use DOAC at 1 hour after TAVI in F1 + 2 (600 [452 to 765] vs 1055 [812 to 1340] pmol/L; p < 0.001), TAT (21.4 [16.2 to 37.0] vs 38.7 [26.4 to 58.7] µg/mL; p < 0.001) and on day 1 in SFMC (18.2 [9.4 to 57.9] vs 113.4 [70.9 to 157.3] µg/mL; p < 0.001) and day 2 in FDP (6.0 [4.7 to 10.0] vs 12.6 [8.2 to 17.4] µg/mL; p < 0.001). Ischemic stroke within 30 days after TAVI occurred in 3 patients (1.5%), who were not treated with DOAC. Coagulation cascade activation was observed after TAVI. DOAC could reduce transient hypercoagulation following TAVI.

Reduced Rivaroxaban Dose Versus Dual Antiplatelet Therapy After Left Atrial Appendage Closure: ADRIFT a Randomized Pilot Study.

BACKGROUND: Percutaneous left atrial appendage closure (LAAC) exposes to the risk of device thrombosis in patients with atrial fibrillation who frequently have a contraindication to full anticoagulation. Thereby, dual antiplatelet therapy (DAPT) is usually preferred. No randomized study has evaluated nonvitamin K antagonist oral anticoagulant after LAAC, and we decided to evaluate the efficacy and safety of reduced doses of rivaroxaban after LAAC. METHODS: ADRIFT (Assessment of Dual Antiplatelet Therapy Versus Rivaroxaban in Atrial Fibrillation Patients Treated With Left Atrial Appendage Closure) is a multicenter, phase IIb study, which randomized 105 patients after successful LAAC to either rivaroxaban 10 mg (R10, n=37), rivaroxaban 15 mg (R15, n=35), or DAPT with aspirin 75 mg and clopidogrel 75 mg (n=33). The primary end point was thrombin generation (prothrombin fragments 1+2) measured 2 to 4 hours after drug intake, 10 days after treatment initiation. Thrombin-antithrombin complex, D-dimers, rivaroxaban concentrations were also measured at 10 days and 3 months. Clinical end points were evaluated at 3-month follow-up. RESULTS: The primary end point was reduced with R10 (179 pmol/L [interquartile range (IQR), 129-273], P<0.0001) and R15 (163 pmol/L [IQR, 112-231], P<0.0001) as compared with DAPT (322 pmol/L [IQR, 218-528]). We observed no significant reduction of the primary end point between R10 and R15 while rivaroxaban concentrations increased significantly from 184 ng/mL (IQR, 127-290) with R10 to 274 ng/mL (IQR, 192-377) with R15, P<0.0001. Thrombin-antithrombin complex and D-dimers were numerically lower with both rivaroxaban doses than with DAPT. These findings were all confirmed at 3 months. The clinical end points were not different between groups. A device thrombosis was noted in 2 patients assigned to DAPT. CONCLUSIONS: Thrombin generation measured after LAAC was lower in patients treated by reduced rivaroxaban doses than DAPT, supporting an alternative to the antithrombotic regimens currently used after LAAC and deserves further evaluation in larger studies. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT03273322.

Supplementation with antithrombin III ex vivo optimizes enoxaparin responses in critically injured patients.

BACKGROUND: The high incidence of venous thromboembolism (VTE) following trauma persists in spite of aggressive thromboprophylaxis strategies. Approximately half of VTE patients do not achieve the recommended anti-FXa response to enoxaparin anticoagulation (0.1-0.4 IU/mL), however, research to explain or correct this phenomenon is lacking. We hypothesized that antithrombin III (AT) deficiency is associated with poor enoxaparin responsiveness in trauma patients that develop VTE which can be reversed through supplementation with AT. METHODS AND FINDINGS: A retrospective cohort study was performed on plasma collected from trauma patients who did and did not develop pulmonary embolism (PE) as well as healthy volunteers. AT levels, thrombin generation, and anti-FXa levels were measured in the collected plasma at baseline and in response to supplementation with AT concentrate at 120-200% or plasma (30% volume). A total of 54 PE patients and 46 non-PE patients were enrolled in this study for analysis. Compared to healthy volunteers, trauma patients had lower levels of AT, elevated thrombin generation, and lower anti-FXa levels in response to enoxaparin. Moreover, thrombin generation was higher and responses to enoxaparin were lower in patients who developed PE compared to those who did not develop PE. We found that supplementation with AT, but not plasma, increased AT levels and improved enoxaparin-mediated inhibition of thrombin generation. CONCLUSIONS: Supplementation with AT may provide a novel adjunct therapy to increase the effectiveness of enoxaparin thromboprophylaxis and reduce the incidence of VTE in the trauma population.

Antithrombin III Attenuates AKI Following Acute Severe Pancreatitis.

BACKGROUND: Antithrombin III (ATIII), the predominant coagulation factor inhibitor, possesses anti-inflammatory properties and exerts renoprotective effects on renal ischemia-reperfusion injury in animal models. However, the ATIII's protective effects of ATIII on acute kidney injury (AKI) following severe acute pancreatitis (SAP) need to be confirmed. METHODS: We assessed the association between ATIII activities and the incidence of AKI in patients with SAP, and explored therapeutic effects and potential mechanisms of ATIII on kidney injury in sodium taurocholate induced SAP rat model. Rats were intravenously injected with ATIII (500 µg/kg) before or after the induction of SAP. RESULTS: The results demonstrated ATIII did not attenuate pancreatic injury, but significantly ameliorate renal dysfunction and renal histological injury. ATIII administration alleviated renal inflammation response, oxidative stress, and cell apoptosis. Moreover, ATIII attenuated tumor necrosis factor α (TNFα)-stimulated intercellular cell adhesion molecule 1(ICAM-1) and monocyte chemotactic protein 1 (MCP-1) upregulation in cultured renal tubular epithelial cells. CONCLUSION: ATIII appears to ameliorate SAP-induced kidney injury by inhibiting inflammation, oxidative stress, and apoptosis. ATIII supplementation may have a potential prophylactic and therapeutic effect on SAP induced AKI.

Evening primrose oil or forskolin ameliorates celecoxib-enhanced upregulation of tissue factor expression in mice subjected to lipopolysaccharide-induced endotoxemia.

Celecoxib, a selective cyclooxygenase-2 inhibitor, produces thrombotic events in patients predisposed to cardiovascular risk factors. One theory reported an increase in endothelial expression of tissue factor (TF) as a predisposing factor. This work explored the effect of evening primrose oil (EPO), a source of prostaglandin E1, and forskolin (a cyclic adenosine monophosphate stimulator) against the prothrombotic effect of celecoxib in mice. Lipopolysaccharide mouse model of endotoxemia was used to induce an upregulation of TF activity. Male mice received celecoxib (25 mg/kg), celecoxib plus EPO, or celecoxib plus forskolin for 4 weeks and then subjected to a prothrombotic challenge in the form of an intraperitoneal injection of lipopolysaccharide. Results showed an increase in plasma TF activity, endothelial TF expression, and thrombin-antithrombin (TAT) but lower antithrombin III (ATIII) level in mice that received celecoxib in comparison to those that received the vehicle. Adding EPO or forskolin to celecoxib regimen significantly decreased the prothrombotic effect of celecoxib. A positive correlation (r = 0.8501) was found between TF activity and TAT. Co-administration of EPO or forskolin decreased the activity of TF and mitigated the prothrombotic effect of celecoxib. Therefore, these combinations may have the utility to abrogate the prothrombotic adverse effect of celecoxib in clinical setting.

Antithrombin III improved neutrophil extracellular traps in lung after the onset of endotoxemia.

BACKGROUND: Coagulation and inflammation are closely linked during acute inflammatory conditions, such as sepsis. Antithrombin (AT) is an anticoagulant that also has anti-inflammatory activities. The effects of therapeutically administering AT III after the onset of endotoxemia or sepsis were not clear. Here, we studied the effects of administering AT III after inducing lethal endotoxemia in mice. METHODS: Mice were injected intraperitoneally with lipopolysaccharide (LPS) to induce endotoxemia. AT III was administered 3 h later. We assessed survival and the severity of endotoxemia and quantified plasma cytokine levels and biochemical markers of liver and kidney function. In the lungs, we examined neutrophil accumulation, neutrophil extracellular traps, alveolar wall thickness, and chemokine (C-X-C motif) ligand 1 (cxcl-1), cxcl-2, and high mobility group box 1 expression. RESULTS: Administering AT III reduced the severity and mortality of LPS-induced endotoxemia as indicated by 24-h survival of 84% of the mice that received LPS + AT III and only 53% of mice given LPS alone (P < 0.05). AT III treatment attenuated several changes induced in the lungs by endotoxemia including cxcl-2 mRNA expression, high mobility group box 1 protein expression, neutrophil accumulation, alveolar septal thickening, and neutrophil extracellular trap formation. AT III did not decrease plasma cytokine levels or plasma urea nitrogen levels that were upregulated as a result of LPS-induced endotoxemia. CONCLUSIONS: Administration of AT III after the onset of endotoxemia improved outcomes in a mouse model. The attenuation of lung inflammation may have a large impact on mortality and morbidity. Because lung inflammation increases the likelihood of mortality from sepsis, AT III could be a useful agent in septic patients.

[Atrial Septal Defect with Hereditary Deficiency of Antithrombin III].

A 41-year-old female with hereditary deficiency of antithrombin III (ATIII) was diagnosed with atrial septal defect( ASD) and scheduled for the closure of ASD. She had been taking warfarin since she suffered from deep vein thrombosis 10 years ago. Preoperative management of anticoagulation included discontinuation of warfarin, and supplementation of antithrombin with heparin infusion. On the day of operation, antithrombin activity was maintained above 80% by administering antithrombin, and closure of ASD was carried out under standard cardiopulmonary bypass support using heparin. Heparin infusion was continued with antithrombin supplementation until prothrombin time-international normalized ratio(PT-INR) recovered to around 2.5 with warfarin. Her intra-and postoperative courses did not show any thromboembolic events, and she was discharged 20 days after the surgery.

Comparative studies of pharmacokinetics and anticoagulatory effect in rats after oral administration of Frankincense and its processed products.

ETHNOPHARMACOLOGICAL RELEVANCE: Frankincense (FRA), Ruxiang, is the resin of Boswellia carterii Birdw and Boswellia bhaw-dajiana Birdw which has been used for centuries as formulas to improve the circulation and to relieve pain against carbuncles. Stir-fried Frankincense (SFF) and vinegar processed Frankincense (VPF) are two major processed Frankincense, and the processing procedures reportedly enhance the curative efficacy or reduce the side effects of FRA. This paper describes the comparisons in plasma pharmacokinetic behaviors of 11-keto-ß-boswellic acid (KBA) and 3-acetyl-11-keto-ß-boswellic acid (AKBA) in FRA and its processed products, and their effects on coagulation factors and blood clotting tetrachoric, using an acute cold blood-stasis animal model after oral administration of FRA, SFF, and VPF. MATERIALS AND METHODS: For pharmacokinetic study, Sprague-Dawley (SD) rats were randomly divided into three groups, including group FRA, group SFF and group VPF. And the plasma samples were analyzed by HPLC. For study of anticoagulatory effect, SD rats were randomly divided into six groups, including control, acute cold blood-stasis model, Fu-fang-dan-shen tablet- (0.75g/kg), FRA-, SFF-, and VPF-treated (2.7g/kg) groups, respectively. The serum contents of thrombin-antithrombin complex (TAT), D-dimer (D-D), and prostacyclin (PGI2) of each group were measured by ELISA. The values of prothrombin time (PT), thrombin time (TT), activated partial thromboplastin time (APTT) and fibrinogen (FIB) were also assessed by hematology analyzer. RESULTS: Significantly increased levels of Cmax, AUC, T1/2, and MRT were found in rats treated with the processed products. In addition, decreased levels of D-D and TAT and increased contents of PGI2 were observed in rats given FRA and its processed products, compared with that of the model group. Moreover, VPF improved anticoagulation more than SFF in the animals. CONCLUSIONS: The observed improvement of anticoagulation by processed FRA may result from the increased absorption and bioavailability of triterpenoids.

Synthesis and Evaluation of a Series of Long-Acting Glucagon-Like Peptide-1 (GLP-1) Pentasaccharide Conjugates for the Treatment of Type†2 Diabetes.

The present study details the development of a family of novel D-Ala(8) glucagon-like peptide-1 (GLP-1) peptide conjugates by site specific conjugation to an antithrombin III (ATIII) binding carrier pentasaccharide through tetraethylene glycol linkers. All conjugates were found to possess potent insulin-releasing activity. Peptides with short linkers (<25 atoms) conjugated at Lys(34) and Lys(37) displayed strong GLP-1 receptor (GLP-1-R) binding affinity. All D-Ala(8) GLP-1 conjugates exhibited prominent glucose-lowering action. Biological activity of the Lys(37) short-linker peptide was evident up to 72 h post-injection. In agreement, the pharmacokinetic profile of this conjugate (t1/2 , 11 h) was superior to that of the GLP-1-R agonist, exenatide. Once-daily injection of the Lys(37) short-linker peptide in ob/ob mice for 21 days significantly decreased food intake and improved HbA1c and glucose tolerance. Islet size was decreased, with no discernible change in islet number. The beneficial effects of the Lys(37) short-linker peptide were similar to or better than either exenatide or liraglutide, another GLP-1-R agonist. In conclusion, GLP-1 peptides conjugated to an ATIII binding carrier pentasaccharide have a substantially prolonged bioactive profile compatible for possible once-weekly treatment of type 2 diabetes in humans.

Peri-procedural use of rivaroxaban in elective percutaneous coronary intervention to treat stable coronary artery disease. The X-PLORER trial.

Patients on rivaroxaban requiring percutaneous coronary intervention (PCI) represent a clinical conundrum. We aimed to investigate whether rivaroxaban, with or without an additional bolus of unfractionated heparin (UFH), effectively inhibits coagulation activation during PCI. Stable patients (n=108) undergoing elective PCI and on stable dual antiplatelet therapy were randomised (2:2:2:1) to a short treatment course of rivaroxaban 10 mg (n=30), rivaroxaban 20 mg (n=32), rivaroxaban 10 mg plus UFH (n=30) or standard peri-procedural UFH (n=16). Blood samples for markers of thrombin generation and coagulation activation were drawn prior to and at 0, 0.5, 2, 6-8 and 48 hours (h) after start of PCI. In patients treated with rivaroxaban (10 or 20 mg) and patients treated with rivaroxaban plus heparin, the levels of prothrombin fragment 1 + 2 at 2 h post-PCI were 0.16 [0.1] nmol/l (median) [interquartile range, IQR] and 0.17 [0.2] nmol/l, respectively. Thrombin-antithrombin complex values at 2 h post-PCI were 3.90 [6.8]µg/l and 3.90 [10.1] µg/l, respectively, remaining below the upper reference limit (URL) after PCI and stenting. This was comparable to the control group of UFH treatment alone. However, median values for thrombin-antithrombin complex passed above the URL with increasing tendency, starting at 2 h post-PCI in the UFH-alone arm but not in rivaroxaban-treated patients. In this exploratory trial, rivaroxaban effectively suppressed coagulation activation after elective PCI and stenting.

Efficacy of argatroban in critically ill patients with heparin resistance: a retrospective analysis.

The patients who do not respond even to very high dosages of heparin are assumed to suffer from heparin resistance. The aim of this study was to investigate whether critically ill patients suffering from heparin resistance generally have low antithrombin III (AT) levels, and if the direct thrombin inhibitor argatroban in that case can be an effective option to achieve prophylactic anticoagulation. The study was conducted at the Department for General and Surgical Intensive Care Medicine at the University Hospital Innsbruck. We retrospectively included all patients between 2008 and 2012, who received argatroban because of poor response to high-dosage heparin prophylaxis. The period under observation lasted in total for 9 days, 2 days of anticoagulation with unfractionated heparin (UFH) and 7 days with argatroban. The primary objective was to investigate if after 7 (± 1) hours of switching to argatroban the activated partial thromboplastin time (aPTT) levels were in a prophylactic range of 45 to 55 seconds. Further objectives were to assess the AT level, side effects such as bleeding or thromboembolism, platelet count, correlation between organ function and argatroban dose as well as any need for allogeneic blood products. The study population, consisting of 5 women and 15 men with a mean (± standard deviation, SD) age of 54.6 ± 16.3 years, differed in many clinical aspects. A median (interquartile range) heparin dose of 1,000, 819 to 1,125 IU/h was administered for 2 days and failed in providing a prophylactic anticoagulation measured by the aPTT. The mean aPTT level with heparin treatment was 38.5 seconds (± 4.7) its change within that period was not significant. After switching to argatroban, the mean increase of the aPTT levels in all study patients amounted from 38.5 to 48.3 seconds (p < 0.001). The rise in aPTT clearly reaches sufficient prophylactic anticoagulant levels. The maintenance of prophylactic aPTT levels was achieved over the period of 1 week. There was neither a correlation found between low-AT levels and occurrence of heparin resistance, nor between the simplified acute physiology score II and the administered argatroban dose (r = -0.224, p = 0.342). The results of the present study indicate that argatroban is an effective alternative therapy, especially in critically ill patients, to achieve prophylactic anticoagulation when heparin resistance occurs.

Antithrombotic triple therapy and coagulation activation at the site of thrombus formation: a randomized trial in healthy subjects.

BACKGROUND: Patients with acute coronary syndrome and concomitant atrial fibrillation may require antithrombotic triple therapy but clinical evidence of safety and efficacy is poor. We have therefore studied the combination of different antithrombotic medicines for coagulation activation in an in vivo model in the skin microvasculature. METHODS AND RESULTS: Platelet activation (ß-thromboglobulin [ß-TG]) and thrombin generation (prothrombin fragment 1 + 2 [F1+2 ], thrombin-antithrombin complex [TAT]) were studied in an open-label, randomized, parallel group trial in 60 healthy male subjects (n = 20 per group) who received ticagrelor and acetylsalicylic acid (ASA) in combination with dabigatran (150 mg bid), rivaroxaban (20 mg od) or phenprocoumon (INR 2.0-3.0). Coagulation biomarkers in shed blood were assessed at 3 h after monotherapy with the medicines under study, at 3 h after triple therapy dosing and at steady state trough conditions. Single doses of ticagrelor, dabigatran or rivaroxaban caused comparable decreases in shed blood ß-TG and were more pronounced than phenprocoumon at an INR of 2.0-3.0. In contrast, thrombin generation was more affected by rivaroxaban and phenprocoumon than by dabigatran. During triple therapy a similarly sustained inhibition of platelet activation and thrombin generation with a maximum decrease of ß-TG, F1+2 and TAT at 3 h post-dosing was noted, which remained below pre-dose levels at trough steady state. CONCLUSION: A triple therapy at steady state with ticagrelor plus ASA in combination with dabigatran or rivaroxaban is as effective as a combination with phenprocoumon for platelet activation and thrombin generation in vivo.

Targeted mutagenesis of zebrafish antithrombin III triggers disseminated intravascular coagulation and thrombosis, revealing insight into function.

Pathologic blood clotting is a leading cause of morbidity and mortality in the developed world, underlying deep vein thrombosis, myocardial infarction, and stroke. Genetic predisposition to thrombosis is still poorly understood, and we hypothesize that there are many additional risk alleles and modifying factors remaining to be discovered. Mammalian models have contributed to our understanding of thrombosis, but are low throughput and costly. We have turned to the zebrafish, a tool for high-throughput genetic analysis. Using zinc finger nucleases, we show that disruption of the zebrafish antithrombin III (at3) locus results in spontaneous venous thrombosis in larvae. Although homozygous mutants survive into early adulthood, they eventually succumb to massive intracardiac thrombosis. Characterization of null fish revealed disseminated intravascular coagulation in larvae secondary to unopposed thrombin activity and fibrinogen consumption, which could be rescued by both human and zebrafish at3 complementary DNAs. Mutation of the human AT3-reactive center loop abolished the ability to rescue, but the heparin-binding site was dispensable. These results demonstrate overall conservation of AT3 function in zebrafish, but reveal developmental variances in the ability to tolerate excessive clot formation. The accessibility of early zebrafish development will provide unique methods for dissection of the underlying mechanisms of thrombosis.

[Dependence of the anticoagulant activity of starch and inulin on their degree of sulfonation].

We have studied a relationship between the degree of sulfonation and anticoagulant activity of starch from Solanum tuberosum (molecular weight, 25000-30000 Da; sulfonation degree, 0.4-2.5) and inulin from Helianthus tuberosus (molecular weight, 7000-8000 Da; sulfonation degree, 0.6-1.6). Starch and inulin sulfates (i) increased the time of appearance of fibrin clots in plasma in coagulometric tests and (ii) reduced (via antithrombin) the rate of thrombin-induced hydrolysis of a chromogen substrate. The antithrombin (aIIa) activity of starch sulfates reached 16.8-70.0 IU/mg and the activity against factor Xa (aXa activity) was 2.3-16.6 IU/mg. The antithrombin activity of inulin sulfates was within 5.5-11.4 IU/mg and the activity against factor Xa (aXa activity) was within 0-1.4 IU/mg. An increase in the degree of sulfonation led to a growth in the anticoagulant activity of starch sulfates. The anticoagulant activity of starch sulfates and inulin sulfate with sulfonation degree 1.0 is mediated by antithrombin, which is the plasma inhibitor of serine proteases.

Moutan cortex radicis improves lipopolysaccharide-induced acute lung injury in rats through anti-inflammation.

Moutan cortex radicis (MCR) is a Chinese herbal medicine that was widely used over a long period as an analgesic, antipyretic, and anti-inflammatory agent in China. Lipopolysaccharide (LPS)-induced acute lung injury (ALI) in rat models is considered similar to adult respiratory distress syndrome (ARDS) in humans. Therefore, the present study investigates the effect of MCR on ALI. The ALI model was developed through the intra-tracheal (IT) administration of LPS (16mg/kg) to Sprague-Dawley (SD) rats, which formed the LPS group. MCR was orally administered before and after LPS was introduced into rats (MCR-LPS group and LPS-MCR group, respectively). In the MCR-LPS group, rats received MCR 2g/kg/times 3 times before LPS challenge; the LPS-MCR group received MCR 2g/kg/times 3 times after LPS challenge. The results of this experiment indicate that the number of total cells and neutrophils and the concentration of protein exudation in bronchoalveolar lavage fluid (BALF) significantly decreased in the MCR-LPS group. Cytokine levels, including levels of interleukin (IL)-1ß, macrophage-inflammatory peptide (MIP)-2, IL-6, and IL-10, in BALF were also significantly inhibited at 16h after LPS administration in the MCR-LPS group. Myeloperoxidase (MPO) activity in lung tissue was reduced in the MCR-LPS and LPS-MCR groups at 16h after LPS administration. Furthermore, leukocyte infiltration and protein exudation in the alveolar space were less severe in the MCR-LPS group than in the LPS group. Therefore, the findings of this study suggest that the administration of MCR prior to LPS improves ALI, possibly mediating ALI through anti-inflammation.