Perioperative Management of Patients Taking Direct Oral Anticoagulants: A Review.

Importance: Direct oral anticoagulants (DOACs), comprising apixaban, rivaroxaban, edoxaban, and dabigatran, are commonly used medications to treat patients with atrial fibrillation and venous thromboembolism. Decisions about how to manage DOACs in patients undergoing a surgical or nonsurgical procedure are important to decrease the risks of bleeding and thromboembolism. Observations: For elective surgical or nonsurgical procedures, a standardized approach to perioperative DOAC management involves classifying the risk of procedure-related bleeding as minimal (eg, minor dental or skin procedures), low to moderate (eg, cholecystectomy, inguinal hernia repair), or high risk (eg, major cancer or joint replacement procedures). For patients undergoing minimal bleeding risk procedures, DOACs may be continued, or if there is concern about excessive bleeding, DOACs may be discontinued on the day of the procedure. Patients undergoing a low to moderate bleeding risk procedure should typically discontinue DOACs 1 day before the operation and restart DOACs 1 day after. Patients undergoing a high bleeding risk procedure should stop DOACs 2 days prior to the operation and restart DOACs 2 days after. With this perioperative DOAC management strategy, rates of thromboembolism (0.2%-0.4%) and major bleeding (1%-2%) are low and delays or cancellations of surgical and nonsurgical procedures are infrequent. Patients taking DOACs who need emergent (<6 hours after presentation) or urgent surgical procedures (6-24 hours after presentation) experience bleeding rates up to 23% and thromboembolism as high as 11%. Laboratory testing to measure preoperative DOAC levels may be useful to determine whether patients should receive a DOAC reversal agent (eg, prothrombin complex concentrates, idarucizumab, or andexanet-α) prior to an emergent or urgent procedure. Conclusions and Relevance: When patients who are taking a DOAC require an elective surgical or nonsurgical procedure, standardized management protocols can be applied that do not require testing DOAC levels or heparin bridging. When patients taking a DOAC require an emergent, urgent, or semiurgent surgical procedure, anticoagulant reversal agents may be appropriate when DOAC levels are elevated or not available.

Simultaneous quantification of baloxavir marboxil and its active metabolite in human plasma using UHPLC-MS/MS: Application to a human pharmacokinetic study with different anticoagulants.

Baloxavir marboxil (BXM) is a cap-dependent nucleic acid endonuclease inhibitor, which exerts its antiviral effects after being metabolized to its active form baloxavir acid (BXA). Ethylenediamine tetra-acetic acid (EDTA) and heparin are the two most used anticoagulants in clinical blood sample collection to estimate drug levels in plasma. However, compared to heparin plasma, there is a lack of clinical pharmacokinetic data of BXA using EDTA anticoagulant tubes for blood collection. In the present study, an efficient, rapid, and sensitive ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for simultaneous quantification of BXM and its active metabolite BXA in human plasma with its isotopic baloxavir-d5 (BXA-d5) as internal standard (IS). Plasma samples (50 µL) were undergone using acetonitrile containing 0.1 % formic acid a precipitant. Chromatographic separation was achieved by a Waters XBridge®C8 (2.1 mm × 50 mm, 2.5 µm) column. The gradient mobile phase was 0.1 % formic acid in water (A, pH 2.8) and 0.1 % formic acid in acetonitrile (B) and delivered at a flow rate of 0.6 mL/min for 4.5 min. BXM and BXA were monitored using a positive electrospray triple quadrupole mass spectrometer (TRIPLE QUAD™ 6500+) via multiple reaction monitoring mode. The mass-to-charge ratios (m/z) were 572.2→247.0, 484.2→247.0 and 489.2→252.0 for BXM, BXA, and BXA-d5 (IS). Calibration curves exhibited excellent linearity in the range of 0.1-10 ng/mL for BXM (r2 > 0.996), and 0.3-300 ng/mL for BXA (r2 > 0.998). Within-run and between-run precisions in coefficients of variations were less than 11.62 % for BXM and less than 7.47 % for BXA, and accuracies in relative error were determined to be within -7.78 % to 5.70 % for BXM and -6.67 % to 8.56 % for BXA. Extraction recovery efficiency was 92.76 % for BXM, 95.32 % for BXA, and 99.26 % for BXA-d5, respectively. The matrix effect of BXM and BXA was in line with the requirements, where the relative deviation of the accuracy was less than 6.67 % and the precision was less than 6.69 %. The validated efficient and simple UHPLC-MS/MS method was successfully used in the pharmacokinetic study of BXM and BXA in healthy human volunteers with K2EDTA and heparin tubes for blood collection. EDTA might compete with BXA for chelating metal ions and thereby decrease the plasma ratio in whole blood, leading to approximately 50 % lower measurement of pharmacokinetic parameters as compared with those obtained from heparin plasma anticoagulant tubes.

Dual benefits of NBD-Cl fluorogenic action and sample pretreatment (SALLE) technology in the assessment of anticoagulant medication: Dabigatran in pharmaceutical capsules and plasma samples.

Dabigatran (DBG), marketed as Pradaxa, is an anticoagulant medication prescribed for the treatment and mitigation of blood clots and to lower the risk of stroke in individuals with the heart condition known as atrial fibrillation. This medication is specifically indicated for preventing blood clots post hip or knee replacement surgeries and in patients with a prior history of clots. Compared to warfarin, dabigatran serves as a viable alternative that does not necessitate routine blood monitoring tests. The complimentary benefits associated with SALL (salting-out assisted liquid-liquid extraction) and the fluorogenic capabilities of benzofurazan. These methods were combined to provide an affordable and sensitive DBG assaying method. The spectral strength of the yellow luminous product was examined at 533.8 nm and by adjustment of a wavelength of 474.7 nm for excitation. To assess its linearity, the calibration chart was tested across a DBG concentration range of 30-500 ng/ml. Via accurate computation based on ICH, the detection limit (LD) was determined to be 9.5 ng/ml, and the strategy can quantify the DBG to a limit of 28 ng/ml. To ensure success, various crucial parameters for method implementation have been extensively studied and adapted. The validation of the strategy adhered to the policies outlined by ICH, affirming its precision in quantifying DBG in capsules. Furthermore, the inclusion of SALLE steps facilitated accurate monitoring of DBG in plasma samples, introducing a unique and advanced methodology for analyzing this compound in biological samples.

The Effects of Different Blood Sample and Anticoagulant Types on Quantitative Tests of B-Type Natriuretic Peptide.

BACKGROUND: BNP is a sensitive and widely used biomarker for an early diagnosis of heart failure. Currently, most commercial BNP detection products use EDTA plasma samples. The aim of this study was to evaluate the clinical performance of the BNP test by using whole blood samples compared to plasma samples, and to evaluate the effect of the anticoagulant type on the BNP test result. METHODS: In total, 106 patients with different BNP levels from the Dahua Hospital volunteered for this study. Clinically homogenous samples, including EDTA anticoagulant plasma, EDTA whole blood, and heparin anticoagulant plasma, were collected and analyzed by using i-Reader S automatic immuno-analyzer and its supporting reagent kits. Pearson's correlation and weighted least squares linear regression analysis, Bland-Altman plotting, and Kappa test were used for statistical analysis. RESULTS: Correlation analysis showed that BNP concentrations, measured from EDTA anticoagulated plasma samples, had a good linear regression relationship with BNP from whole blood samples, with a slope of 0.9477, r = 0.9978, p < 0.05. A similar correlation was observed between EDTA anticoagulated plasma samples and heparin anticoagulant plasma, with a slope of 0.8413, r = 0.9793, p < 0.05. The BNP concentration measured from the heparin plasma samples were lower than of the EDTA plasma samples. Bland-Altman analysis for assessing BNP concentration agreement showed there was no outlier ratio between EDTA whole blood and EDTA plasma within the range of the detection system, as well as no outlier between EDTA anticoagulated and heparin anticoagulant plasma. Kappa coefficient of BNP concentration between homologous EDTA anticoagulated and heparin anticoagulant plasma was 0.8553 (p < 0.001), and for EDTA anticoagulated plasma and homologous whole blood it was 0.8941 (p < 0.001). CONCLUSIONS: The diagnostic performance of EDTA anticoagulated whole blood samples did not differ significantly from EDTA anticoagulated plasma samples for the BNP test. This study showed no big significant difference between EDTA anticoagulated and heparin anticoagulated plasma measurements within 2 hours. The type of anticoagulant should be carefully chosen when performing the BNP test if BNP samples were in vitro for a long time.

Quantifying time from last dose: do direct oral anticoagulant assays correlate with patient's reported last dose.

INTRODUCTION: In the absence of a patient's last direct oral anticoagulant (DOAC) dose time, best practice regarding preoperative DOAC cessation remains unclear. The aim of this study was to investigate, in a real-life patient cohort, if there was an association between subjective patient recall and objective DOAC assay titre. METHODS/MATERIALS: A multicentre cohort study of consecutive surgical inpatients was conducted. DOAC assays were 'expected' if they satisfied both time and titre-based guidelines. RESULTS: Patient-recalled last dose and DOAC assay was available in 285 individuals. DOAC assay titres correlated strongly with the expected levels based on a patient's reported last dose time(rho = 0.70, P value < 0.0001). However, underweight (<50 kg; P  = 0.0339) and elderly (>80 years; P  = 0.0134) were more likely to have an unexpectedly high assay titre. CONCLUSIONS: A significant portion (∼25%) of patients had unexpected DOAC titres. DOAC levels can be clinically impactful in a significant percentage of patients, particularly in elderly and/or underweight.

Supraprophylactic Anti-Factor Xa Levels Are Associated with Major Bleeding in Neurosurgery Patients Receiving Prophylactic Enoxaparin.

BACKGROUND: Prior studies demonstrated reduced risk for venous thromboembolism (VTE) in neurosurgical patients secondary to prophylaxis with both heparin and low-molecular-weight heparin. The ability to monitor low-molecular-weight heparin by obtaining anti-factor Xa (anti-Xa) serum levels provides an opportunity to evaluate safety and efficacy. The aim of this study was to describe characteristics of patients who have anti-Xa levels outside of the goal range (0.2-0.4/0.5 IU/mL) and investigate incidence of major bleeding and VTE. METHODS: A single-center, retrospective, observational study was conducted on neurosurgical patients receiving enoxaparin for VTE prophylaxis between August 2019 and December 2020. Significance testing was conducted via Fisher exact test and independent samples t test. RESULTS: The study included 85 patients. Patients were less likely to have an anti-Xa level in the goal range if they were male, had a higher weight, or were morbidly obese. Three neuroendovascular patients (3.5%) experienced a major bleed. Serum anti-Xa levels were significantly higher in patients who experienced major bleeds compared with patients who did not (0.45 ± 0.16 IU/mL vs. 0.28 ± 0.09 IU/mL, P = 0.003). Patients with a supraprophylactic anti-Xa level (>0.5 IU/mL) were more likely to experience a major bleed (P = 0.005). One VTE event occurred: the patient experienced a pulmonary embolism with anti-Xa level at goal. CONCLUSIONS: Anti-Xa-guided enoxaparin dosing for VTE prophylaxis in neurosurgical patients may help prevent major bleeding. These data suggest that a higher anti-Xa level may predispose patients to major bleeding. Further evaluation is needed to identify the goal anti-Xa level for VTE prophylaxis in this population.

Influence of CYP2C9 Polymorphisms on Plasma Concentration of Warfarin and 7-Hydroxy Warfarin in South Indian Patients.

BACKGROUND: Warfarin is primarily metabolized by cytochrome P450 2C9 (CYP2C9) enzyme, which is encoded by the CYP2C9 gene. CYP2C9*2 and CYP2C9*3 variants significantly influence warfarin metabolism and subsequently the required dose of warfarin. OBJECTIVES: The current retrospective study was aimed to determine the influence of CYP2C9 variants on warfarin metabolic ratio (MR, warfarin/7-hydroxy warfarin) and warfarin maintenance therapy in 210 patients (mean age 44.6±11.6 (SD) years; male to female ratio 81:129). METHODS: High-performance liquid chromatography (HPLC) with UV detector was used to measure plasma concentrations of warfarin and 7-hydroxy warfarin. Plasma samples were collected 12 h after the previous dose of warfarin was administered. CYP2C9 variants (rs1799853 and rs1057910) were identified using real-time polymerase chain reaction allele-discrimination method. RESULTS: The mean daily maintenance dose of warfarin was 4.6±1.8 (SD) mg. The mean plasma warfarin and 7-hydroxy warfarin concentrations were 3.7±1.6 (SD) µg/mL and 1.1±0.54 (SD) µg/mL, respectively. Patients carrying other CYP2C9 variants required 39% lower warfarin maintenance dose 3.3±1.2(SD)mg than CYP2C9*1*1 carrier 4.9±1.8(SD)mg, (p<0.0001). MRs differed significantly between CYP2C9 variant carriers (8.1±5.1) and normal genotype carriers (4.8±3.9) (p<0.0001). Probit analysis identified an MR value of 7.6 as the anti-mode (sensitivity of 84% and specificity of 55%) to differentiate poor and intermediate metabolizers (carriers of any CYP2C9*2 or CYP2C9*3 variants) from normal metabolizers (CYP2C9*1*1 genotype). CONCLUSION: The present study results provide, insights on the effect of CYP2C9 genetic polymorphisms on inter-individual variability in warfarin metabolism and emphasizes utility of phenotyping in a setting of genotype-guided dosing of warfarin in South Indian population.

Development and validation of an ultra-high performance liquid chromatography with tandem mass spectrometry method for the simultaneous quantification of direct oral anticoagulants in human plasma.

Direct oral anticoagulants are widely used to treat and prevent thromboembolic disorders. With rising clinical application, monitoring concentrations of direct oral anticoagulants are necessary in certain clinical conditions. A rapid and sensitive ultra-performance liquid chromatography-tandem mass spectrometry method was developed for the simultaneous determination of dabigatran etexilate, dabigatran, rivaroxaban, edoxaban, and apixaban, in human plasma. Protein precipitation with methanol was performed for sample preparation. The direct oral anticoagulants and internal standards were separated under gradient conditions using a C18 column, at an analytical run time of 8 min. The mobile phase was composed of 0.1% (v/v) formic acid in water (solvent A) and 0.1% (v/v) formic acid in acetonitrile (solvent B) at a flow rate of 0.3 mL/min. Mass detection was performed in multiple reaction monitoring using positive ionization mode. The method was validated over a range of 1.0-500 ng/mL for dabigatran etexilate, 0.1-500 ng/mL for dabigatran, and 0.5-500 ng/mL for edoxaban, rivaroxaban, and apixaban. The method detection limits of five analytes were in the range of 0.05-0.5 ng/mL. The lower limits of quantification of five analytes ranged from 0.1 to 1 ng/mL. The linearity (r2 values) was higher than 0.997. The accuracy of the low, medium, and high quality control samples were between 85.9 and 114%, and intra- and inter-day precision were below 9.47%. This validated method was successfully used to determine the plasma concentrations of rivaroxaban in 32 patients, and of dabigatran etexilate and dabigatran in 1 patient.

A study of the influence of lead pollution on the anticoagulant activity of Whitmania pigra based on pharmacodynamics and metabolomics research.

Whitmania pigra Whitman (leech, also called Shuizhi in China, abbreviated as SZ), which has been used as a traditional Chinese medicine in the treatment of blood stasis syndrome (BSS) for a long time, is vulnerable to lead pollution in aquaculture environments. SZ has good anticoagulant activity. However, there are few studies on the influence of lead pollution on it. Therefore, we carried out the following researches to explore the influence of lead pollution on the anticoagulant activity of SZ and its mechanism. Firstly, the acute blood stasis model of rats was established by subcutaneous injection of adrenaline hydrochloride and ice water bath. Then unpolluted SZ (UPS) and lead-polluted SZ (LPS) were extracted. Next, the blood stasis model rats were administrated by gavage and the rats in normal control (NC) group and blood stasis model (BM) group were given the same amount of normal saline. Finally, the blood of the rats was collected to detect the coagulation function and hemorheology indexes. The metabolomics of rat plasma was studied by ultra-high-performance liquid chromatography coupled with orbitrap mass spectrometry (UPLC-Orbitrap-MS) technology. Principal component analysis (PCA), orthogonal partial least squares discriminant analysis (OPLS-DA) and Hierarchical clustering analysis (HCA) were used to perform metabolomics analysis. MetPA analysis was used to search for related metabolic pathways. The results of coagulation function and hemorheology showed that lead pollution could decrease the anticoagulant activity of SZ. The OPLS-DA score plots indicated that the plasma metabolites of rats in LPS group were close to BM group, while UPS group tended to be close to NC group both in the positive and negative ion mode. Hierarchical cluster analysis (HCA) suggested that UPS group and NC group were clustered into a branch, while LPS group and BM group were clustered into a branch. To sum up, lead pollution will reduce the anticoagulant activity of SZ. And lead pollution reduces the anticoagulant activity of SZ probably by influencing the metabolic pathways such as sphingolipid metabolism, amino acid metabolism and energy metabolism in rats.

Predicting Range of Initial Warfarin Dose Based on Pharmacometabolomic and Genetic Inputs.

Anticoagulation response to warfarin during the initial stage of therapy varies among individuals. In this study, we aimed to combine pharmacometabolomic and pharmacogenetic data to predict interindividual variation in warfarin response, and, on this basis, suggest an initial daily dose range. The baseline metabolic profiles, genotypes, and clinical information of 160 patients with heart valve disease served as the variables of the function of the last international normalized ratio measured before a patient's discharge (INRday7 ) to screen for potential biomarkers. The partial least-squares model showed that two baseline metabolites (uridine and guanosine), one single-nucleotide variation (VKORC1), and four clinical parameters (weight, creatinine level, amiodarone usage, and initial daily dose) had good predictive power for INRday7 (R2  = 0.753 for the training set, 0.643 for the test set). With these biomarkers, a machine learning algorithm (two-dimensional linear discriminant analysis-multinomial logit model) was used to predict the subgroups with extremely warfarin-sensitive or less warfarin-sensitive patients with a prediction accuracy of 91% for the training set and 90% for the test set, indicating that individual responses to warfarin could be effectively predicted. Based on this model, we have successfully designed an algorithm,"IniWarD," for predicting an effective dose range in the initial 7-day warfarin therapy. The results indicate that the daily dose range suggested by the IniWarD system is more appropriate than that of the conventional genotype-based method, and the risk of bleeding or thrombus due to warfarin could thus be avoided.

Evaluation of the in vitro stability of direct oral anticoagulants in blood samples under different storage conditions.

In this study, we evaluated the in vitro stability of direct oral anticoagulants (DOACs) in blood samples of 57 patients under different storage conditions using functional coagulation assays. We determined the analyte concentrations (1) immediately after blood collection (baseline); (2) after storage of citrated whole blood (agitated) at room temperature and citrated plasma at room temperature and at 4 °C for 4, 8, and 24 h, respectively; and (3) after storage of citrated plasma at -20 °C for 30, 60, and 90 days. According to the concept of acceptable change limits (ACL), analytes were considered stable if the mean relative analyte recovery at a given time was >78%. The mean baseline values (range) of dabigatran, rivaroxaban, apixaban, and edoxaban were 115 ng/mL (62-217), 129 ng/mL (31-215), 156 ng/mL (49-362), and 101 ng/mL (33-283), respectively. After applying the analyte stability limit, all four DOACs were stable for 24 h at room temperature and at 4 °C. The mean recovery after 24 h was 102-111% for dabigatran, 88-97% for rivaroxaban, 95-98% for apixaban, and 90-96% for edoxaban. When plasma samples were stored at -20 °C, the mean percentage deviation after 90 days for all four DOACs was ≤10%, even after three freeze-thaw cycles. Thus, for the correct determination of DOAC plasma concentrations, blood samples do not have to be analyzed immediately and can be stored at room temperature for up to 24 h before analysis. In clinical practice, blood sample transport and storage for DOAC measurements appear to be unproblematic.

Impact of body mass index on 90-day warfarin requirements: a retrospective chart review.

BACKGROUND: Rates of obesity continue to rise worldwide as evidenced in the 2017 Centers for Disease Control and Prevention (CDC) report that indicated over 35% of United States (US) citizens are obese, with Louisiana ranked as the fifth most obese state in America. Since large clinical trials tend to exclude obese patients, health care providers are faced with concerns of under- or overdosing these patients on warfarin. METHODS: This retrospective chart review evaluated patients who reported to a community anticoagulation clinic for warfarin management between 1 June 2017 and 30 September 2017. Along with baseline demographics, chronic use of drugs that have clinically significant interactions with warfarin, social activity such as tobacco use and alcohol consumption, were collected. Body mass indexes (BMI) were collected and categorized according to the World Health Organization definitions as follows: Normal (BMI 18-24.9 kg/m2), Overweight (25-29.9 kg/m2), Obesity Class I (30-34.9 kg/m2), Obesity Class II (35-39.9 kg/m2), Obesity Class III (⩾40 kg/m2). The primary outcome was the mean 90-day warfarin dose required to maintain "intermediate control" or "good control" of international normalized ratio (INR), stratified by BMI classifications. The secondary outcome was the time in therapeutic range (TTR) stratified by BMI classifications. RESULTS: A total of 433 patient encounters were included in this study. There was a total of 43 encounters in the Normal BMI category, 111 Overweight encounters, 135 Obesity Class I encounters, 45 Obesity Class II encounters, and 99 Obesity Class III encounters. Approximately 63% of the study population were male, and over 90% the patients were African American. The Obesity Class I and Obesity Class II class required an average of 11.47 mg and 17.10 mg more warfarin, respectively, to maintain a therapeutic INR when compared with the Normal BMI category. These findings were statistically significant with p values of 0.007 and <0.001, respectively. Additionally, upon comparing the Overweight BMI category with the Obesity Class II category, there was a mean warfarin dose difference of 11.22 mg (p = 0.010) more in Obesity Class II encounters to maintain a therapeutic INR. In the secondary analysis of TTR, Overweight category encounters had the highest TTR, whereas encounters in the Normal BMI category had the lowest TTR. CONCLUSION: As BMI increases, there is an increased chronic warfarin requirement to maintain "intermediate control" or "good control" of INR between 2 and 3 in an ambulatory care setting.

A synergy of liquid chromatography with high-resolution mass spectrometry and coagulation test for determination of direct oral anticoagulants for clinical and toxicological purposes.

Direct oral anticoagulants are an alternative to anticoagulants based on vitamin K antagonists. Monitoring of direct oral anticoagulant concentration levels is necessary in specific cases (e.g. in emergency conditions, for determination of the cause of bleeding, adverse effects, risk of drug-direct oral anticoagulants interaction); therefore, a sensitive and specific method is needed. A methanol protein precipitation method followed by liquid chromatography with high-resolution mass spectrometry was developed for simultaneous separation and determination of apixaban, betrixaban, edoxaban, dabigatran, rivaroxaban and ximelagatran. The proposed method was fully validated in terms of linearity, the limits of detection and quantification, intra- and inter-day trueness and precision, recovery, matrix effect, process efficiency and stability. The method shows a strong correlation (Pearson's correlation coefficients > 0.92) with coagulation assays of apixaban, dabigatran and rivaroxaban (dilute thrombin time for gatrans and anti Xa factor (anti-Xa) activity for xabans). In addition, the developed method was applied for the identification and determination of apixaban and dabigatran in post-mortem serum samples. The developed method is a good alternative to coagulation tests which may show various interferences.

A phase I, single and continuous dose administration study on the safety, tolerability, and pharmacokinetics of neorudin, a novel recombinant anticoagulant protein, in healthy subjects.

The aim of this study was to evaluate the tolerability, safety, and pharmacokinetics of single and continuous dose administration of recombinant neorudin (EPR-hirudin, EH) by intravenous administration in healthy subjects, and to provide a safe dosage range for phase II clinical research. Forty-four subjects received EH as a single dose of between 0.2 and 2.0 mg/kg by intravenous bolus and drip infusion. In addition, 18 healthy subjects were randomly divided into three dose groups (0.15, 0.30, and 0.45 mg/kg/h) with 6 subjects in each group for the continuous administration trial. Single or continuous doses of neorudin were generally well tolerated by healthy adult subjects. There were no serious adverse events (SAEs), and all adverse events (AEs) were mild to moderate. Moreover, no subjects withdrew from the trial because of AEs. There were no clinically relevant changes in physical examination results, clinical chemistry, urinalysis, or vital signs. The incidence of adverse events was not significantly related to drug dose or systemic exposure. After single-dose and continuous administration, the serum EH concentration reached its peak at 5 min, and the exposure increased with the increase in the administered dose. The mean half-life (T1/2 ), clearance (Cl), and apparent volume of distribution (Vd) of EH ranged from 1.7 to 2.5 h, 123.9 to 179.7 ml/h/kg, and 402.7 to 615.2 ml/kg, respectively. The demonstrated safety, tolerability, and pharmacokinetic characteristics of EH can be used to guide rational drug dosing and choose therapeutic regimens in subsequent clinical studies. Clinical trial registration: Chinadrugtrials.org identifier: CTR20160444.

Towards Development of an Anti-Vampire Bat Vaccine for Rabies Management: Inoculation of Vampire Bat Saliva Induces Immune-Mediated Resistance.

The common vampire bat (Desmodus rotundus) is a hematophagous species responsible for paralytic rabies and bite damage that affects livestock, humans and wildlife from Mexico to Argentina. Current measures to control vampires, based upon coumarin-derived poisons, are not used extensively due in part to the high cost of application, risks for bats that share roosts with vampires and residual environmental contamination. Observations that vampire bat bites may induce resistance in livestock against vampire bat salivary anticoagulants encourage research into novel vaccine-based alternatives particularly focused upon increasing livestock resistance to vampire salivary components. We evaluated the action of vampire bat saliva-Freund's incomplete adjuvant administered to sheep with anticoagulant responses induced by repeated vampire bites in a control group and examined characteristics of vampire bat salivary secretion. We observed that injections induced a response against vampire bat salivary anticoagulants stronger than by repeated vampire bat bites. Based upon these preliminary findings, we hypothesize the utility of developing a control technique based on induction of an immunologically mediated resistance against vampire bat anticoagulants and rabies virus via dual delivery of appropriate host and pathogen antigens. Fundamental characteristics of host biology favor alternative strategies than simple culling by poisons for practical, economical, and ecologically relevant management of vampire populations within a One Health context.

Effect of uterine ozone therapy and anticoagulant sampling on oxidative stress parameters in mares.

With the purpose of assessing the effects of uterine ozone therapy and anticoagulant sampling on oxidative stress (OS) parameters in mares, ten mares underwent three consecutive days of uterine ozone therapy by flushing the uterus with ozonated lactated Ringer's solution followed by insufflation with ozone­oxygen gas. Serum samples were obtained at baseline and days 3, 6, 10 and 17 to determine the effect of ozone therapy on OS markers. Plasma obtained with anticoagulants citrate, ethylenediaminetetraacetic acid (EDTA) and heparin were at baseline and 6 days following therapy to determine the effect of anticoagulant on OS parameters. Antioxidants albumin and uric acid, total antioxidant capacity (TAC) using four different methods, total oxidant capacity (TOC) and lipid peroxidation were determined through photocolorimetry. Statistical analyses comprised repeated measures ANOVA followed by Dunnett's test or Friedman followed by Dunn's post-hoc test. Differences were considered significant when p < 0.05. Uterine ozone therapy significantly decreased uric acid, TAC in all four different methods, concomitantly with an increase on TOC at days 3 and 6 following therapy. No changes were observed on albumin and lipid peroxidation levels. Anticoagulants prevented the detection of oxidative stress induced by uterine ozone therapy depending on the method of analysis. In conclusion, uterine ozone therapy causes systemic oxidative stress in mares and the choice of anticoagulant sampling interferes with laboratory tests.