Pharmacology and clinical applications of human recombinant antithrombin

Recombinant thrombomodulin and recombinant antithrombin attenuate pulmonary endothelial glycocalyx degradation and neutrophil extracellular trap formation in ventilator-induced lung injury in the context of endotoxemia

BACKGROUND

Vascular endothelial damage is involved in the development and exacerbation of ventilator-induced lung injury (VILI). Pulmonary endothelial glycocalyx and neutrophil extracellular traps (NETs) are endothelial protective and damaging factors, respectively; however, their dynamics in VILI and the effects of recombinant thrombomodulin and antithrombin on these dynamics remain unclear. We hypothesized that glycocalyx degradation and NETs are induced by VILI and suppressed by recombinant thrombomodulin, recombinant antithrombin, or their combination.

METHODS

VILI was induced in male C57BL/6J mice by intraperitoneal lipopolysaccharide injection (20 mg/kg) and high tidal volume ventilation (20 mL/kg). In the intervention groups, recombinant thrombomodulin, recombinant antithrombin, or their combination was administered at the start of mechanical ventilation. Glycocalyx degradation was quantified by measuring serum syndecan-1, fluorescence-labeled lectin intensity, and glycocalyx-occupied area in the pulmonary vascular lumen. Double-stranded DNA in the bronchoalveolar fluid and fluorescent areas of citrullinated histone H3 and myeloperoxidase were quantified as NET formation.

RESULTS

Serum syndecan-1 increased, and lectin fluorescence intensity decreased in VILI. Electron microscopy revealed decreases in glycocalyx-occupied areas within pulmonary microvessels in VILI. Double-stranded DNA levels in the bronchoalveolar lavage fluid and the fluorescent area of citrullinated histone H3 and myeloperoxidase in lung tissues increased in VILI. Recombinant thrombomodulin, recombinant antithrombin, and their combination reduced glycocalyx injury and NET marker levels. There was little difference in glycocalyx injury and NET makers between the intervention groups.

CONCLUSION

VILI induced glycocalyx degradation and NET formation. Recombinant thrombomodulin and recombinant antithrombin attenuated glycocalyx degradation and NETs in our VILI model. The effect of their combination did not differ from that of either drug alone. Recombinant thrombomodulin and antithrombin have the potential to be therapeutic agents for biotrauma in VILI.

A systematic review and meta-analysis of the effectiveness of primary thromboprophylaxis in acute lymphoblastic leukemia during early-phase therapy including asparaginase or its prolonged form

Asparaginase is essential in the initial management of acute lymphoblastic leukemia (ALL) but frequently leads to venous thromboembolism (VTE). Using anticoagulants for primary VTE prevention has been studied with no consensus. We conducted a systematic literature search in PubMed, Scopus, and Web of science and performed random-effect meta-analysis using Mantel-Haenszel method in RevMan 5.4 to analyze primary pharmacological thromboprophylaxis during asparaginase treatment in early-phase (induction, consolidation, or intensification phase) therapy in patients with ALL with all ages and followed with subgroup analysis by age. Meta-analysis of 13 articles describing the effect of antithrombin supplementation in 1375 patients showed that antithrombin prophylaxis decreases the risk of VTE by 43% (RR, 0.57; 95% CI, 0.38 - 0.83; p=0.004), with mild heterogeneity (I2=35%, p=0.10) and moderate certainty by GRADE. 8 articles included for meta-analysis of low-molecular weight heparin (LMWH) treatment in 612 patients showed that it decreased the risk of VTE by nearly 40% (RR, 0.61; 95% CI, 0.45 - 0.81; p=0.00081), with minimal heterogeneity (I2=14%, p=0.31) but low certainty. Subgroup analysis showed that only prophylaxis with antithrombin supplementation significantly decreased the VTE rate in adult patients with moderate certainty. In pediatric patients, one nonrandomized prospective study showed that LMWH combined with antithrombin has a better thromboprophylaxis effect than antithrombin alone. In the PREVAPIX-ALL trial, prophylaxis with direct factor Xa inhibitor Apixaban did not benefit children younger than 18 years except for cases of obesity. We concluded that thromboprophylaxis with antithrombin is effective in ALL patients older than 18 years during the early phase of therapy, and LMWH combined with antithrombin supplementation might be effective for pediatric patients with ALL. Apixaban is effective in pediatric ALL patients with obesity and needs further study in other high-risk patients.

The Improved Milk Quality and Enhanced Anti-Inflammatory Effect in Acetylserotonin-O-methyltransferase (ASMT) Overexpressed Goats: An Association with the Elevated Endogenous Melatonin Production

BACKGROUND

Transgenic animal production is an important means of livestock breeding and can be used to model pharmaceutical applications.

METHODS

In this study, to explore the biological activity of endogenously produced melatonin, Acetylserotonin-O-methyltransferase (ASMT)-overexpressed melatonin-enriched dairy goats were successfully generated through the use of pBC1-ASMT expression vector construction and prokaryotic embryo microinjection.

RESULTS

These transgenic goats have the same normal phenotype as the wild-type goats (WT). However, the melatonin levels in their blood and milk were significantly increased (p < 0.05). In addition, the quality of their milk was also improved, showing elevated protein content and a reduced somatic cell number compared to the WT goats. No significant changes were detected in the intestinal microbiota patterns between groups. When the animals were challenged by the intravenous injection of E. coli, the ASMT-overexpressed goats had a lower level of pro-inflammatory cytokines and higher anti-inflammatory cytokines compared to the WT goats. Metabolic analysis uncovered a unique arachidonic acid metabolism pattern in transgenic goats.

CONCLUSIONS

The increased melatonin production due to ASMT overexpression in the transgenic goats may have contributed to their improved milk quality and enhanced the anti-inflammatory ability compared to the WT goats.

Single Low Dose of Human Recombinant Antithrombin (ATryn) has no Impact on Endotoxin-Induced Disseminated Intravascular Coagulation: An Experimental Randomized Open Label Controlled Study

BACKGROUND

Antithrombin (AT) III physiological levels are decreased during septic shock and supplementation therapy could therefore be beneficial.

OBJECTIVE

We hypothesized that the use of recombinant human AT could reduce disseminated intravascular coagulation (DIC) occurrence.

METHODS

We conducted a randomized open label controlled experimental study. Ten female "Large White" pigs were challenged with i.v. infusion of Escherichia coli endotoxin. Two groups of 5 pigs were randomly assigned to receive either recombinant human AT 100 U/kg over 30 min (ATryn group) or 0.9% saline (control group). AT III levels, coagulation, hemostasis, inflammation parameters, hemodynamics, and microcirculatory parameters were measured over a 5-h period. Immediately after euthanasia, kidneys were withdrawn for histology evaluation. Statistical analysis was performed with nonparametric tests and Dunn's test for multiple comparisons.

RESULTS

AT III activity was significantly higher in the ATryn group than in the control group from 60% (213% [203-223] vs. 104% [98-115], P = 0.008, respectively) to 300 min (115% [95-124] vs. 79% [67-93], P = 0.03). Recombinant human AT supplementation had no impact on hemodynamics, microcirculatory parameters, and sequential changes of coagulation parameters (platelet count, fibrinogen level, thrombin-AT complexes, and von Willebrand factor). Interleukin 6 and tumor necrosis factor α values were statistically the same for both groups throughout the study. Percentage of thrombosed glomeruli and percentage of thrombosed capillary in glomerulus were not significantly different between both groups.

CONCLUSIONS

In our model of endotoxic shock, a single low dose of recombinant human AT did not prevent DIC occurrence, severity, inflammatory profile, or hemodynamic alterations.

Knockdown of serpin peptidase inhibitor clade C member 1 inhibits the growth of nasopharyngeal carcinoma cells

Nasopharyngeal carcinoma (NPC) is a type of cancer originating in the nasopharynx. There are no NPC‑specific treatments available at present. Serpin peptidase inhibitor clade C member 1 (SERPINC1) serves roles in anticoagulation and anti‑inflammation. The aim of the present study was to investigate the role of SERPINC1 in the proliferation and apoptosis of NPC cells. Tumor and adjacent healthy tissue samples were collected from patients with NPC. Additionally, the SERPINC1 gene was silenced in the HNE3 cell line using short interfering RNA targeted against SERPINC1 (SERPINC1‑siRNA). Cell viability was determined via a Cell Counting Kit‑8 assay; furthermore, proliferation and apoptosis were investigated via flow cytometry. Western blotting and reverse transcription‑quantitative polymerase chain reaction analysis were performed to determine the expression levels of protein and mRNA. It was revealed that the expression levels of SERPINC1 mRNA and protein were increased in NPC tumor tissues compared with in adjacent healthy tissues. The expression of SERPINC1 mRNA and protein in HNE3 cells decreased following SERPINC1‑siRNA transfection. Furthermore, knockdown of SERPINC1 promoted apoptosis and inhibited proliferation. It was also demonstrated that silencing SERPINC1 upregulated the expression of B‑cell lymphoma-2 (Bcl‑2)‑associated X protein and p53 mRNA and protein, and downregulated that of Bcl‑2, survivin and cyclin D1. Downregulation of SERPINC1 reduced the phosphorylation of phosphatidylinositol 3‑kinase (PI3K), protein kinase B (Akt) and mammalian target of rapamycin (mTOR). Thus, SERPINC1 knockdown may promote the apoptosis of HNE3 cells and inhibit proliferation via the suppression of the PI3K/Akt/mTOR signaling pathway.

Small Peptides as Modulators of Serine Proteases

Serine proteases play critical roles in many physiological and pathological processes, and are proven diagnostic and therapeutic targets in a number of clinical indications. Suppression of the aberrant proteolytic activities of these proteases has been clinically used for the treatments of relevant diseases. Polypeptides with 10-20 residues are of great interests as medicinal modulators of serine proteases, because these peptides demonstrate the characteristics of both small molecule drugs and macromolecular drugs. In this review, we summarized the recent development of peptide-based inhibitors against serine proteases with potent inhibitory and high specificity comparable to monoclonal antibodies. In addition, we also discussed the strategies of enhancing plasma half-life and bioavailability of peptides in vivo, which is the main hurdle that limits the clinical translation of peptide-based drugs. This review advocates new avenue for the development of effective serine protease inhibitors and highlights the prospect of the medicinal use of these inhibitors.

Treatment for disseminated intravascular coagulation in patients with acute and chronic leukemia

BACKGROUND

Disseminated intravascular coagulation (DIC) is an acquired syndrome characterized by systemic intravascular activation of coagulation, leading to deposition of fibrin in the bloodstream. It may occur in patients with acute and chronic leukemia and is particularly associated with acute promyelocytic leukemia (a subtype of acute myeloid leukemia).

OBJECTIVES

To assess the clinical benefits and harms of any pharmacological intervention for treating DIC in patients with acute or chronic leukemia.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2015, Issue 05), MEDLINE (1946 to 7 May 2015), LILACS (1982 to 7 May 2015) and African Index Medicus (7 May 2015). There was no language restrictions. We sought additional randomized controlled trials (RCTs) from the World Health Organization International Clinical Trials Registry Platform and the reference lists of primary studies identified.

SELECTION CRITERIA

RCTs assessing the clinical benefits and harms of interventions for treating DIC in patients with acute and chronic leukemia.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed trial selection, 'Risk of bias' assessment and data extraction. Primary outcomes were overall mortality, in-hospital mortality from any cause (15-day and 30-day) and adverse events.

MAIN RESULTS

In this Cochrane Review update we did not include any new RCT compared with the first review version. Accordingly, four RCTs (388 participants) met the inclusion criteria. These trials evaluated the human activated protein C, recombinant human soluble thrombomodulin, tranexamic acid and dermatan sulphate. Included trials reported data on mortality and bleeding. The studies were conducted in Japan, Italy and the Netherlands. We classified the included trials as: 1) including patients with or without leukemia which did not report data for the leukemia subgroup (366 participants); and 2) only including patients with leukemia (22 participants). Overall, the risk of bias of the included trials was high, since the trial authors did not provide a detailed description about trial design and execution.According to the GRADE recommendations, we judged the overall quality of the body of evidence for all prefixed outcomes as 'very low', due to methodological limitations and very small sample size.One trial, including 10 participants with leukemia and comparing dermatan sulphate with heparin, reported no deaths during trial treatment.In terms of bleeding data, we were unable to pool results from two studies that were only conducted with leukemia patients due to the inconsistency in the measurement and reporting of this outcome. One trial, including 12 participants with leukemia, found very low quality evidence that tranexamic acid can reduce the cumulative hemorrhagic score in participants compared with those assigned to placebo (P = 0.0015, very low quality evidence). On the contrary, there is no evidence that dermatan sulphate compared with placebo reduces new events of hemorrhagic diathesis (1/5 (20%) versus 2/5 (40%); RR 0.50; 95% CI 0.06 to 3.91; P = 0.51, very low quality evidence).No thromboembolic complications were reported in either trial that included patients with leukemia only (very low quality evidence). The safety profile was inconclusive.The included trials did not assess overall mortality, resolution of respiratory failure, renal failure or shock.

AUTHORS' CONCLUSIONS

Due to a lack of new RCTs, our conclusions in this Cochrane Review update are the same as the previous review version. We included four RCTs which reported mortality and bleeding data. It is not possible to determine whether human activated protein C, recombinant human soluble thrombomodulin, tranexamic acid and dermatan sulphate are effective or harmful for patients presenting with DIC related to acute or chronic leukemia. The quality of the evidence was low to very low. Therefore, prescription of these interventions for treating DIC in patients with acute and chronic leukemia can neither be supported nor rejected, unless new evidence from a large high-quality trial alters this conclusion.

Clinical syndromes associated with acquired antithrombin deficiency via microvascular leakage and the related risk of thrombosis

Antithrombin (AT) is a 65kDa glycoprotein belonging to a group of inhibitory factors known as serpins (serine protease inhibitors). It plays a critical role in the inhibition of coagulation and inflammation processes within the environment of the vascular endothelium. Inadequate levels of functional AT in plasma results in an increased risk of thrombotic events, both venous and arterial. AT deficiency can be inherited or acquired. Congenital AT deficiency is the most severe inherited thrombophilic condition with an odds ratio of 20 for the increased risk of venous thrombosis. Acquired AT deficiency occurs in a variety of physiologic and pathologic medical conditions with similar risks of increased thrombosis. In this article, we review clinical settings characterized by an acquired AT deficiency largely or partly subsequent to protein microvascular leakage. Other different mechanisms of AT depletion are implied in some clinical conditions together with endothelial loss, and, therefore, outlined. In addition, we provide a description of the current knowledge on the specific mechanisms underlying endothelial AT leakage and on the consequences of this protein decrease, specifically looking at thrombosis. We identify potential directions of research that might prove useful in patients with acquired AT deficiency.

Pharmacokinetics of recombinant human antithrombin in delivery and surgery patients with hereditary antithrombin deficiency

Population pharmacokinetic (PK) analyses were conducted to refine dosing recommendations for recombinant human anti-thrombin therapy in surgery and delivery patients with hereditary antithrombin deficiency (HD). Single-dose PK data from patients with HD and nonlinear mixed-effects modeling were used to devise a dosing regimen to target antithrombin (AT) activity levels between 80% and 120% of normal. External validation with data from a phase 3 trial confirmed the correctness of a covariate-free model for surgery patients, but dosing adjustment was necessary for delivery patients. After different covariates were tested, the model was updated to incorporate the influential covariate, delivery. Simulations were used to develop a therapeutic drug-monitoring scenario that results in steady state AT activity levels within the target range as quickly as practically feasible. Data from a second clinical trial provided additional external validation and confirmed the accuracy of the dosing model for both groups of patients.

Bioequivalence of two intravenous formulations of antithrombin III: a two-way crossover study in healthy Korean subjects

BACKGROUND

Treatment with antithrombin (AT)-III is indicated for patients with sepsis or hereditary AT deficiency.

OBJECTIVE

The purpose of this study was to compare the pharmacokinetic and pharmacodynamic characteristics of 2 AT-III formulations in healthy Korean volunteers to satisfy the regulatory requirements for bioequivalence for marketing purposes.

METHODS

A single-center, single-dose, open-label, randomized, 2-period, 2-sequence crossover study was conducted in healthy Korean volunteers. Blood samples for the drug analysis were collected for up to 216 hours after drug administration. Participants received either the test or reference formulation of AT-III 100 U/kg IV for 20 minutes in the first period and the alternative formulation in the second period. Both the AT-III activity and antigen (Ag) were measured for the analysis of pharmacokinetic properties, and the prothrombin time and the activated partial thromboplastin time were assessed for the analysis of pharmacodynamic properties. Because AT-III is an endogenous compound, the analysis used data corrected from baseline values. The tolerability of the 2 formulations was also assessed based on physical examinations including vital sign measurements, laboratory tests, and 12-lead ECG.

RESULTS

Of the 20 subjects enrolled (mean [SD] age, height, and weight, 25.3 [2.3] years, 175.3 [4.5] cm, and 67.4 [6.3] kg, respectively), 19 completed both treatment periods; 1 subject withdrew consent for personal reasons. The observed mean (SD) Cmax, AUClast, and AUC0-∞ of AT-III activity were, respectively, 279.24% (35.92), 14,364.10 (2325.25) %·h, and 17,526.38 (3150.81) %·h with the test formulation and 249.75% (31.96), 12,962.95 (1897.52) %·h, and 15,957.67 (3189.21) %·h with the reference formulation. The observed mean (SD) Cmax, AUClast, and AUC0-∞ of AT-III Ag were 62.58 (5.66) mg/dL, 3051.94 (401.87) mg/dL·h, and 3639.80 (726.01) mg/dL·h, respectively, with the test formulation and 58.63 (5.27) mg/dL, 2805.08 (272.38) mg/dL·h, and 3340.00 (428.46) mg/dL·h with the reference formulation. The geometric mean ratios (90% CI) of the log-transformed data for AT-III activity between the 2 formulations were 1.11494 (1.08994-1.14053) for Cmax, 1.11305 (1.05435-1.17503) for AUClast, and 1.11527 (1.03754-1.19889) for AUC0-∞; corresponding values for AT-III Ag were 1.08802 (1.06258-1.11405), 1.10905 (1.05804-1.16242), and 1.11460 (1.02058-1.21726). During the study period, 8 adverse events were reported, and all were transient, mild, and resolved completely during the treatment period.

CONCLUSION

The results of the present study showed that these 2 AT-III formulations met the regulatory criteria for pharmacokinetic bioequivalence with respect to AT-III activity and Ag in these healthy Korean subjects. ClinicalTrials.gov identifier: NCT00846274.

Evaluation of electrospray ionization mass spectrometry as a tool for characterization of small soluble protein aggregates

Protein aggregation continues to attract significant interest in many areas of biology and medicine not only due to its pivotal role in the etiology of conformational diseases (such as Parkinson's and Alzheimer's) but also due to its importance in the biopharmaceutical sector, where aggregation of protein therapeutics exerts a deleterious effect on their efficacy and safety. Despite the tremendous success of electrospray ionization mass spectrometry (ESI MS) in a large number of studies of noncovalent protein interactions, application of this technique to study aggregation processes has been very limited so far, and lower resolution techniques, such as size exclusion chromatography (SEC) and analytical ultracentrifugation, remain the default tools in characterizing small soluble protein aggregates. In this work we used heat-stressed human antithrombin III (AT), a 58 kDa glycoprotein, to compare SEC and ESI MS as a means to probe composition of the complex mixture of soluble oligomeric species generated by heat-induced aggregation. SEC allows several oligomeric species to be observed and collected, followed by their identification with ESI MS. The same oligomeric species can be also directly observed in the ESI MS of the unfractionated sample of the heat-stressed AT. The abundance distribution of these small soluble aggregates in ESI MS and SEC cannot be compared directly, since the ESI signal is linked to the molar concentration of the analyte in solution, whereas the UV absorption detection in SEC reports weight concentration. However, once the appropriate corrections are made, the abundance of the small aggregates derived from ESI MS becomes remarkably close to that calculated based on SEC data, suggesting that ESI MS may be directly applied for semiquantitative characterization of soluble protein aggregates.

Treatment for disseminated intravascular coagulation in patients with acute and chronic leukemia

BACKGROUND

Disseminated intravascular coagulation (DIC) is an acquired syndrome characterized by systemic intravascular activation of coagulation, leading to deposition of fibrin in the bloodstream, that may occur in patients with acute and chronic leukemia.

OBJECTIVES

To assess the clinical effectiveness and safety of any pharmacological intervention for treating DIC in acute or chronic leukemia.

SEARCH STRATEGY

The search strategy included the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 12), MEDLINE (1950 to 28 October 2010), EMBASE (1980 to 10 October 2010), LILACS (1982 to 19 August 2010) and African Index Medicus (1993 to 19 August 2010). There was no language restriction. We sought additional randomized controlled trials (RCTs) from the World Health Organization (WHO) Clinical Trials Registry Platform and by using the reference lists of primary studies found.

SELECTION CRITERIA

RCTs assessing the effectiveness of interventions for treating disseminated intravascular coagulation (DIC) in patients with acute and chronic leukemia.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed study selection, risk of bias assessment and data extraction.

MAIN RESULTS

Four RCTs (126 participants) met the inclusion criteria. These trials evaluated the human activated protein C, recombinant human soluble thrombomodulin, tranexamic acid and dermatan sulphate. Included RCTs reported data on mortality and bleeding. The included RCTs were classified as: 1) including patients with or without leukemia, and 2) only including patients with leukemia. However, data were not reported for the leukemia subgroup. We were not able to pool results from studies due to the inconsistency in the measurement and reporting of mortality and bleeding data. The included studies were at high risk of bias.

AUTHORS' CONCLUSIONS

We found four RCTs which reported mortality and bleeding data. It is not possible to determine whether human activated protein C, recombinant human soluble thrombomodulin, tranexamic acid and dermatan sulphate are effective or harmful for patients presenting with DIC related to acute or chronic leukemia. The effects of these interventions need to be tested in sufficiently powered RCTs. Outcome measures should include in-hospital mortality from any cause, overall mortality, incidence of resolution of respiratory failure, renal failure, shock and safety. The definition of bleeding should be standardized in these patients.