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.

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.

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.

Portal vein thrombosis treated using danaparoid sodium and antithrombin III.

A 45-year-old man under treatment for liver cirrhosis (LC) due to chronic hepatitis C and hemophilia A was seen in our emergency room because of a 10-kg weight gain in the previous week due to ascites. Portal vein thrombosis (PVT) was detected with computer tomography (CT) and ultrasonographic (US). Danaparoid sodium (DS) and antithrombin III (AT III) were administrated and doppler US images showed improvement of portal venous blood flow. DS or AT III may be safe and alternative therapies for PVT.

Rivaroxaban -- an oral, direct Factor Xa inhibitor: lessons from a broad clinical study programme.

Anticoagulants are recommended for the prevention and treatment of venous thromboembolism (VTE), prevention of stroke in patients with atrial fibrillation (AF) and secondary prevention in patients with acute coronary syndrome (ACS). There is a clinical need for novel anticoagulants offering improvements over current standard of care, such as fixed oral dosing and no need for routine monitoring. Rivaroxaban, an oral, once-daily, direct Factor Xa inhibitor, has recently completed the RECORD phase III programme for the prevention of VTE in patients undergoing total hip or knee replacement (THR or TKR), an indication for which it is approved in Europe and Canada. It is being investigated in large-scale phase III studies for VTE treatment and prevention of stroke in patients with AF, and phase III studies will soon commence for secondary prevention in patients with ACS. Phase I studies demonstrated that no routine anticoagulation monitoring was required, while phase II studies suggested that fixed daily doses had a wide therapeutic window. The four RECORD studies consistently showed that rivaroxaban was significantly more effective than enoxaparin in the prevention of VTE after THR and TKR, with a similar safety profile. This review describes the development of this novel anticoagulant, from bench to bedside.

Apixaban, an oral direct Factor Xa inhibitor: awaiting the verdict.

For the last half-century, despite its many limitations warfarin has been the mainstay of treatment for patients with venous and arterial thromboembolic disease. During the past decade, a number of new oral anticoagulant agents have been developed that may offer an alternative to warfarin. Emerging data suggest that Factor Xa may be a target for inhibition. Apixaban is one such agent. It is a potent, selective, reversible, and orally bioavailable FXa inhibitor that demonstrates antithrombotic efficacy, with a favorable pharmacokinetic profile. At present, the safety and efficacy of apixaban for the prophylaxis and treatment of venous thromboembolism is being evaluated in Phase II and Phase III trials involving nearly 25,000 patients. Trials are also underway involving over 20,000 patients for secondary prevention after acute coronary syndromes and the prevention of stroke in patients with non-valvular atrial fibrillation. This review article discusses the discovery, pharmacokinetics, attributes, and current clinical trials of this emerging drug.

Rivaroxaban: an oral direct inhibitor of factor Xa.

PURPOSE: The mechanism of action, pharmacodynamics, pharmacokinetics, efficacy in clinical trials, interactions, adverse effects and toxicity, and place in therapy of rivaroxaban are reviewed. SUMMARY: Rivaroxaban, the first oral, direct factor Xa (FXa) inhibitor to reach Phase III trials, inhibits thrombin generation by both the intrinsic and the tissue factor pathways. It has shown predictable, reversible inhibition of FXa activity, and it may have the ability to inhibit clot-bound FXa. Rivaroxaban is being evaluated for prevention of venous thrombosis in patients undergoing hip or knee arthroplasty, treatment of venous thrombosis, long-term use for secondary prevention of venous thrombosis, and prevention of stroke in atrial fibrillation. To date, only short-term trials have been reported, but rivaroxaban's safety and efficacy appear to be at least equivalent to those of traditional anticoagulants. The results of four studies of primary prevention of venous thrombosis in patients undergoing orthopedic surgery suggest that rivaroxaban 10 mg daily is a promising alternative to low-molecular-weight heparins. Rivaroxaban appears to have a low potential for drug-drug or drug-food interactions. It offers the advantages of a fixed oral dose, rapid onset of action, and predictable and consistent anticoagulation effect, precluding the need for routine monitoring of anticoagulation. CONCLUSION: Rivaroxaban is a promising alternative to traditional anticoagulants for the prevention and treatment of venous thromboembolism and for stroke prevention in atrial fibrillation; it offers once-daily oral administration without the need for routine monitoring.

Rivaroxaban--an oral, direct Factor Xa inhibitor--has potential for the management of patients with heparin-induced thrombocytopenia.

Rivaroxaban is an oral, direct activated Factor Xa (FXa) inhibitor in advanced clinical development for the prevention and treatment of thromboembolic disorders. Currently available anticoagulants include unfractionated heparin (UFH) and low molecular weight heparins (LMWHs); however, their use can be restricted by heparin-induced thrombocytopenia (HIT). HIT is usually caused by the production of antibodies to a complex of heparin and platelet factor-4 (PF4). This study was performed to evaluate, in vitro, the potential of rivaroxaban as an anticoagulant for the management of patients with HIT. UFH, the LMWH enoxaparin, fondaparinux and the direct thrombin inhibitor argatroban were tested to enable comparative analyses. Rivaroxaban did not cause platelet activation or aggregation in the presence of HIT antibodies, unlike UFH and enoxaparin, suggesting that rivaroxaban does not cross-react with HIT antibodies. Furthermore, rivaroxaban did not cause the release of PF4 from platelets and did not interact with PF4, unlike UFH and enoxaparin. These findings suggest that rivaroxaban may be a suitable anticoagulant for the management of patients with HIT.

BAY 59-7939: an oral, direct factor Xa inhibitor for the prevention of venous thromboembolism in patients after total knee replacement. A phase II dose-ranging study.

BACKGROUND: BAY 59-7939, a novel, oral, direct factor Xa inhibitor, is in clinical development for the prevention of venous thromboembolism (VTE), a frequent complication following orthopaedic surgery. METHODS: In a multicenter, parallel-group, double-blind, double-dummy study, 621 patients undergoing elective total knee replacement were randomly assigned to oral BAY 59-7939 (2.5, 5, 10, 20, and 30 mg b.i.d., initiated 6-8 h postsurgery), or subcutaneous enoxaparin (30 mg b.i.d., initiated 12-24 h postsurgery). Treatment was continued until mandatory bilateral venography 5-9 days after surgery. The primary efficacy endpoint was a composite of any deep vein thrombosis (proximal and/or distal), confirmed non-fatal pulmonary embolism and all-cause mortality during treatment. The primary safety endpoint was major, postoperative bleeding during treatment. RESULTS: Of the 613 patients treated, 366 (59.7%) were evaluable for the primary efficacy analysis. The primary efficacy endpoint occurred in 31.7%, 40.4%, 23.3%, 35.1%, and 25.4% of patients receiving 2.5, 5, 10, 20 and 30 mg b.i.d. doses of BAY 59-7939, respectively (test for trend, P = 0.29), compared with 44.3% in the enoxaparin group. The frequency of major, postoperative bleeding increased with increasing doses of BAY 59-7939 (test for trend, P = 0.0007), with no significant difference between any dose group compared with enoxaparin. Bleeding endpoints were lower for the 2.5-10 mg b.i.d. doses compared with higher doses of BAY 59-7939. CONCLUSIONS: Oral administration of 2.5-10 mg b.i.d. of BAY 59-7939, early in the postoperative period, showed potential efficacy and an acceptable safety profile, similar to enoxaparin, for the prevention of VTE in patients undergoing elective total knee replacement.

The race to an orally active Factor Xa inhibitor: recent advances.

Factor Xa (fXa) is a key enzyme in the coagulation cascade and an essential component of the prothrombinase complex, which activates prothrombin to thrombin, leading to fibrin clot formation. In the search for a more effective and safer orally active anticoagulant, fXa has emerged as a major target for potential therapeutic applications in the treatment and prevention of thrombosis. This review focuses on recent advances in the chemistry of drug design and lead optimization of orally bioavailable fXa inhibitors. Many of these orally active fXa inhibitors are currently in clinical trials and are anticipated to change the landscape of thrombosis therapy.

[Effect of antithrombin-III (AT-III) on intestinal epithelium changes related to obstructive icterus: experimental study in rats]. / Etude de l'effet de l'antithrombine-III (AT-III) sur les modifications de l'épithélium intestinal liées à l'ictère obstructif: étude expérimentale chez le rat.

PURPOSE: Bacterial translocation leading to sepsis is increased by obstructive jaundice(OJ). Antithrombin III (ATIII) mediates the promotion of prostaglandin release, an inhibitor of leucocyte activation and downregulator of many proinflammatory cytokines. We investigated the effect of ATIII on histopatology and villus morphology of small intestine. MATERIAL AND METHODS: We designed an experimental study with 40 rats who were divided into four groups. The first one (control, n = 10) received saline, the second (n = 10) included normal rats who received ATIII, the third group (n = 10) was rats with OJ (ligation of common bile duct), and the fourth group included OJ rats receiving AT-III. AT-III (100 UI/kg intraperitoneally) was started at the third day following bile duct ligation and repeated for 5 days. At the 8 day, rats were scarified and ileum was analysed. Histopathological assessments were performed, using a grading scheme ranging from 0 to 10 (Chui et al). RESULTS: Median histological score was found to be 2 in group 1, 1.71 in group 2, 5.43 in group 3 and 2.71 in group 4. The difference between group 3 and 4 was statistically significant. Mucosal thicknesses and villus lengths were found significantly lower in OJ group. Mucosal thicknesses and villus lengths were significantly preserved in jaundiced + AT-III group. CONCLUSION: ATIII demonstrated a salutary effect on the histopathological changes caused by the OJ and prevented the adverse effects on histopathological and morphological parameters in ileal mucosa.

Treatment of human pancreatic cancer in mice with angiogenic inhibitors.

Tumor growth is dependent on the balance of positive and negative regulators of angiogenesis. Antiangiogenic compounds inhibit endothelial cell biology in vitro and angiogenesis in vivo. Therefore antiangiogenic therapy presumes to be an effective treatment for pancreatic cancer. We wanted to determine the effect of antiangiogenic therapy on the growth of human pancreatic cancer in a mouse model. The angiogenesis inhibitors TNP-470 and antiangiogenic antithrombin III (aaATIII) were tested in vitro for their ability to inhibit endothelial cell proliferation. These inhibitors, along with the known antiangiogenic molecule endostatin, were then employed to treat two different primary human pancreatic cancers implanted subcutaneously into the dorsa of immunodeficient (SCID) mice. Treated tumors were examined histologically for microvessel density, apoptosis, and proliferation. All three inhibitors suppressed the growth of pancreatic tumors in vivo. Immunohistochemical analysis revealed increased degrees of apoptosis and reduced microvessel density in treated tumors compared to untreated tumors, although tumor cell proliferation was the same in both groups. None of the inhibitors tested significantly inhibited proliferation of human pancreatic cancer cells, although both TNP-470 and aaATIII were able to inhibit the proliferation of endothelial cells. The observed tumor suppression may be due to increased tumor cell apoptosis as a result of capillary dropout. These studies show that after the angiogenic switch in a human tumor, there is residual production of angiogenesis inhibitors.

Antithrombin reduces ischemia/reperfusion-induced renal injury in rats by inhibiting leukocyte activation through promotion of prostacyclin production.

Antithrombin (AT) supplementation in patients with severe sepsis has been shown to improve organ failures in which activated leukocytes are critically involved. However, the precise mechanism(s) for the therapeutic effects of AT is not well understood. We examined in rats whether AT reduces ischemia/reperfusion (I/R)-induced renal injury by inhibiting leukocyte activation. AT markedly reduced the I/R-induced renal dysfunction and histologic changes, whereas neither dansyl glutamylglycylarginyl chloromethyl ketone-treated factor Xa (DEGR-F.Xa), a selective inhibitor of thrombin generation, nor Trp49-modified AT, which lacks affinity for heparin, had any effect. Renal tissue levels of 6-keto-PGF(1 alpha), a stable metabolite of prostacyclin (PGI(2)), increased after renal I/R. AT enhanced the I/R-induced increases in renal tissue levels of 6-keto-PGF(1 alpha), whereas neither DEGR-F.Xa nor Trp49-modified AT had any effect. AT significantly inhibited I/R-induced decrease in renal tissue blood flow and the increase in the vascular permeability. Ischemia/reperfusion-induced increases in renal tissue levels of tumor necrosis factor-alpha, cytokine-induced neutrophil chemoattractant, and myeloperoxidase were significantly inhibited in animals given AT. Pretreatment of animals with indomethacin reversed the effects induced by AT. Iloprost, an analog of PGI(2), produced effects similar to those induced by AT. These observations strongly suggest that AT reduces the I/R-induced renal injury by inhibiting leukocyte activation. The therapeutic effects of AT might be mainly mediated by PGI(2) released from endothelial cells through interaction of AT with cell surface glycosaminoglycans.

Novel inhibitors of factor X for use in cardiovascular diseases.

The complementary roles of platelets and thrombin in the pathophysiology of acute coronary syndromes suggests that for treatment to be effective, both mediators must be targeted. Although great strides have been made in the development of antiplatelet therapies, attempts to inhibit thrombin have been less successful. Unfractionated heparin is limited by a number of pharmacologic shortcomings as well as an inability to meaningfully suppress thrombin generation. The low molecular weight heparins have yielded encouraging results in large-scale clinical trials, but it remains unclear whether their benefit stems from a superior pharmacologic profile to unfractionated heparin or is determined by an enhanced ability to suppress thrombin generation (by virtue of a direct anti-Xa effect). Regardless, investigators have become increasingly interested in factor Xa as a potential target for antithrombotic therapy. A number of naturally occurring Xa antagonists have been identified. Work with recombinant forms of these proteins confirms that factor Xa inhibition can suppress thrombin generation in a variety of animal thrombosis models. Accordingly, a number of synthetic direct and indirect Xa antagonists are under development for the prevention and treatment of thrombotic disorders. The following review summarizes the evolution of factor Xa antagonists.

Therapeutic use of antithrombin concentrate in sepsis.

Sepsis and its associated complications of disseminated intravascular coagulation (DIC) and multiple organ dysfunction syndrome (MODS) continue to be a major cause of morbidity and mortality. Improved detection of all forms of DIC is essential to assure earlier diagnosis. Studies already indicate that the therapeutic use of antithrombin (AT) concentrate may produce a more positive outcome for sepsis-associated DIC. If DIC could be identified earlier and AT concentrate could then be given earlier in the sepsis continuum, study results for the use of AT concentrate in humans might reveal a statistically significant difference versus placebo, and the efficacy of AT concentrate for this syndrome is more likely to be proved. Fixed-bolus doses of AT concentrate based on body weight are currently preferred, but improved, user-friendly assays for plasma AT levels would permit more rapid turnaround time for AT results and could help fine-tune the use of AT concentrate to the specific needs of each patient. Clinical trials involving the therapeutic use of AT concentrate in sepsis should continue, and it can be hoped that their design will reflect the concepts and conclusions offered by this panel of investigators.

Antithrombin III supplementation in severe sepsis: beneficial effects on organ dysfunction.

Activation of thrombin and of the coagulation system plays an important role in the pathophysiology of sepsis-associated organ dysfunction. Antithrombin III (AT III) is a natural inhibitor of thrombin, a central procoagulatory factor with pleiotropic activities. Experimental supplementation of AT III improved coagulation parameters and ameliorated organ dysfunction. To determine whether long-term AT III supplementation has beneficial effects on organ function, we conducted a randomized, prospective study in surgical patients with severe sepsis. The study evaluated the long-term effect of AT III supplementation (duration of treatment: 14 days). After randomization (AT III vs. control group), AT III was infused continuously over 14 days to obtain plasma AT III activities > 120%. Forty consecutive patients were recruited (20 AT III/20 control group). Eleven patients had a rapid fatal course and did not met the criterion of a 14 day treatment period. From these 11 patients, 8 patients (5 AT III/3 control group) died within 72 h due to septic shock. The remaining 14 AT III patients and 15 controls survived 14 days and showed no differences in baseline parameters of organ function. AT III caused a disappearance of disseminated intravascular coagulation (DIC) in all patients with DIC, whereas in control patients, the frequency of DIC remained constant (p < .05). In AT III patients a progressive increase in oxygenation index (PaO2/FiO2 ratio) and a continuous decrease in pulmonary hypertension index (mean pulmonary artery pressure/mean arterial pressure (PAP/MAP) ratio) indicated an improvement of lung function (p < .05 vs. control). AT III prevented the continuous rise in total serum bilirubin concentration observed in control patients and diminished the frequency of artificial renal support therapy (p < .05). Long-term supplementation with AT III may improve lung function and prevent the development of septic liver and kidney failure in patients with severe sepsis.

The suprapharmacologic dosing of antithrombin concentrate for Staphylococcus aureus-induced disseminated intravascular coagulation in guinea pigs: substantial reduction in mortality and morbidity.

An animal model of gram-positive septicemia was developed to evaluate the effects of antithrombin (AT) concentrates on morbidity, mortality, and laboratory consequences of disseminated intravascular coagulation (DIC). DIC was induced in guinea pigs by infusing Staphylococcus aureus (SA) isolated from blood cultures of patients with DIC (DIC-SA) or without DIC (non-DIC-SA). The non-DIC-SA animals and animals infused with sterile saline served as controls. Varying doses of AT were administered either 30 minutes or 24 hours after infusion of SA. DIC was confirmed within 4 hours by changes in prothrombin time, activated partial thromboplastin time, fibrinogen, fibrinogen-fibrin degradation products, and AT activity. Clinical bleeding was also evident. Mortality of untreated DIC-SA animals was 36% within 24 hours and up to 75% by 72 hours. Intervention with any dose of AT between 125 and 1,000 IU/kg 30 minutes after DIC-SA infusion was associated with 100% survival (P < or = .05 in the 250 IU/kg group) and sustained increases in AT activity and fibrinogen concentrations (P < or = .05). When AT was administered in combination with low molecular weight heparin (LMWH) or if LMWH was adminstered alone, mortality from DIC-SA was slightly, but not significantly reduced compared with untreated DIC-SA. Gross hemorrhage was observed premortem and at autopsy in all of the DIC-SA animals but in substantially fewer animals that received AT (P < or = .001 in the 250, 500, and 1,000 IU/kg groups). In contrast, groups treated with LMWH, alone or with AT, experienced hemorrhage and appeared to develop pathologic DIC. Fibrin formation in end-organs was detected in all guinea pigs in the untreated DIC-SA group and in the groups treated with 125 IU/kg AT and LMWH alone. AT doses between 250 and 1,000 IU/kg administered 30 minutes after DIC-SA infusion prevented fibrin formation in end-organs (P < or = .001 in the 250 and 1,000 IU/kg groups). AT administered 24 hours after DIC-SA could not reverse pre-existing histopathologic evidence of DIC but favorably affected survival, which reached statistical significance in the 1,000 IU/kg AT group (P < or = .025). In summary, suprapharmacologic doses of AT concentrate significantly decreased morbidity and mortality and ameliorated adverse changes in laboratory measures induced by DIC-SA in this guinea pig model and were not associated with untoward hemorrhagic complications. These findings provide justification for studying the use of AT therapy in patients with DIC-SA.

Regulation of thrombosis and hemostasis by antithrombin.

In this article, three cases, with antithrombin (AT) abnormality "Toyama" (type IIb), AT abnormality "Aomori" (type IIa), and congenital AT deficiency (type I) with pregnancy and delivery managed with administration of both AT concentrates and low-molecular-weight heparin, are described. Additionally, a case of AT-producing hepatocellular carcinoma, the first case in the world literature, is reported. Following these clinical reports, the development of AT studies on heparin cofactor II, characteristics of the vessel wall related to coagulation-fibrinolysis, and the development of the treatment of thrombosis with low-molecular-weight heparin and herbal drugs are discussed.

Antithrombin III (AT III) prevents LPS-induced pulmonary vascular injury: novel biological activity of AT III.

Acute respiratory distress syndrome (ARDS) adversely affects the outcome of patients with disseminated intravascular coagulation (DIC) associated with sepsis. To determine whether antithrombin III (AT III) is useful for the treatment of ARDS in sepsis, we evaluated the effect of AT III on lipopolysaccharide (LPS)-induced pulmonary vascular injury in rats. Although the intravenous administration of AT III (250 U/kg) prevented LPS-induced pulmonary accumulation of leukocytes, increases in pulmonary vascular permeability, and coagulation abnormalities, inactivated factor Xa, a selective inhibitor of thrombin generation, did not prevent such events other than the coagulation abnormalities. AT III promotes the endothelial release of prostacyclin by interacting with cell surface glycosaminoglycans in vivo. Trp49-modified AT III, which lacks affinity for heparin, did not prevent LPS-induced pulmonary vascular injury. Plasma levels of 6-keto-prostaglandin F1alpha were markedly increased in rats after the administration of LPS and significantly decreased in the LPS-treated rats administered Trp49-modified AT III, but not altered in those LPS-treated rats receiving AT III. Preventive effects of AT III were not observed in rats pretreated with indomethacin, which inhibits prostacyclin biosynthesis. Prostacyclin prevents LPS-induced pulmonary vascular injury by inhibiting leukocyte accumulation in the lungs. These observations strongly suggest that AT III prevents pulmonary vascular injury induced by LPS by promoting the endothelial release of prostacyclin, a potent inhibitor of leukocyte activation.

Antithrombin III infusion suppresses the hypercoagulable state in adult acute lymphoblastic leukaemia patients treated with a low dose of Escherichia coli L-asparaginase. A GIMEMA study.

Thrombotic events have been reported in acute lymphoblastic leukaemia patients, especially during or after L-asparaginase administration. A so-called L-asparaginase associated coagulopathy has been well recognized, being characterized by a hypercoagulable state (decrease of antithrombin III, plasminogen, protein C, protein S and increase of prothrombin fragment F1 + 2, thrombin-antithrombin complexes and fibrinopeptide A). The aim of this study was to determine whether the supplementation of antithrombin III (AT-III) concentrates could improve the L-asparaginase associated coagulopathy, thereby blocking the activation of the haemostatic system. In 25 adult patients with acute lymphoblastic leukaemia (M 19, F6, mean age 34 years) antithrombin III (AT-III) concentrates were administered at daily doses of 50 U/kg for 10 consecutive days from the beginning of L-asparaginase therapy (6,000 U/m2/day s.c. for 7 days), given according to the GIMEMA ALL 0288 trial. A marked increase of antithrombin III was recorded on days IV-VIII-XI (P < 0.001). No changes in protein C, protein S, plasminogen, alpha 2-antiplasmin, factor VII and platelet count were observed and there was no increase in markers of hypercoagulability. There was no evidence of disseminated intravascular coagulation. In conclusion, AT-III concentrate supplementation during L-asparaginase therapy, by the achievement of high levels of antithrombin III, is associated with a lack of activation of the haemostatic system and appears to overcome the complex coagulopathy associated with L-asparaginase.