Quality control, safety assessment and preparation approaches of low molecular weight heparin.

Low Molecular Weight Heparins (LMWHs) are well-established for use in the prevention and treatment of thrombotic diseases, and as a substitute for unfractionated heparin (UFH) due to their predictable pharmacokinetics and subcutaneous bioavailability. LMWHs are produced by various depolymerization methods from UFH, resulting in heterogeneous compounds with similar biochemical and pharmacological properties. However, the delicate supply chain of UFH and potential contamination from animal sources require new manufacturing approaches for LMWHs. Various LMWH preparation methods are emerging, such as chemical synthesis, enzymatic or chemical depolymerization and chemoenzymatic synthesis. To establish the sameness of active ingredients in both innovator and generic LMWH products, the Food and Drug Administration has implemented a stringent scientific method of equivalence based on physicochemical properties, heparin source material and depolymerization techniques, disaccharide composition and oligosaccharide mapping, biological and biochemical properties, and in vivo pharmacodynamic profiles. In this review, we discuss currently available LMWHs, potential manufacturing methods, and recent progress for manufacturing quality control of these LMWHs.

Chondroitin sulfate from heads of corb: Recovery, structural analysis and assessment of anticoagulant activity.

In this study, glycosaminoglycans (GAGs) were extracted from corb (Sciaena umbra) heads and thoroughly examined for their structure. Through cellulose acetate electrophoresis, the GAGs were identified as chondroitin sulfate (CS), with a recovery yield of 10.35 %. The CS exhibited notable characteristics including a high sulfate content (12.4 %) and an average molecular weight of 38.32 kDa. Further analysis via 1H NMR spectroscopy and SAX-HPLC revealed that the CS primarily consisted of alternating units predominantly composed of monosulfated disaccharides at positions 6 and 4 of GalNAc (52.6 % and 38.8 %, respectively). The ratio of sulfate groups between positions 4 and 6 of GalNAc (4/6 ratio) was approximately 0.74, resulting in an overall charge density of 0.98. Thermal properties of the CS were assessed using techniques such as differential scanning calorimetry and thermogravimetric analysis. Notably, the CS demonstrated concentration-dependent prolongation of activated partial thromboplastin time (aPTT) and thrombin time (TT) while showing no effect on platelet function. At 200 µg/mL, aPTT and TT coagulation times were 1.4 and 3.7 times faster than the control, respectively. These findings suggest that CS derived from corb heads holds promise as an anticoagulant agent for therapy, although further clinical investigations are necessary to validate its efficacy.

Evaluation of the use of a heparin dose-response test in dogs to determine the optimal heparin dose during intravascular procedures and assessment of the in vitro heparin response in healthy dogs.

BACKGROUND: No guidelines for administering and monitoring anticoagulants intraprocedurally are currently available in dogs, despite the prevalence of procedures necessitating systemic anticoagulation with heparin. OBJECTIVES: To evaluate an activated clotting time (ACT)-based heparin dose-response (HDR) test to predict the individual required heparin dose in dogs during intravascular procedures, and to investigate both the in vitro heparin - ACT and in vitro heparin - factor anti-Xa activity (anti-Xa) relationships in dogs. METHODS: Blood was collected from eight healthy beagles undergoing a cardiac procedure and utilised to establish baseline ACT and for in vitro evaluation. Subsequently, 100 IU/kg heparin was administered intravenously (IV) and ACT was remeasured (HDR test). The required heparin dose for an ACT target response ≥300 s was calculated for each individual and ACT was remeasured after administration of this dose. For in vitro testing, a serial heparin blood dilution (0-0.5-1-2-4 international unit (IU)/mL) was prepared and ACT and anti-Xa were determined using whole blood and frozen plasma, respectively. RESULTS: The HDR test overestimated the required heparin dose in 3/7 dogs. In vitro, ACT and anti-Xa increased significantly with increasing blood heparin concentration. Heparin - ACT was nonlinear in 4/8 dogs at heparin concentrations >2 IU/mL, whereas heparin - anti-Xa remained linear throughout the tested range. CONCLUSIONS: The HDR test poorly estimated the required heparin dose in dogs. This is most likely attributed to a nonlinear heparin - ACT relationship, as observed in vitro. Anti-Xa is a promising alternative for ACT; however, unavailability as a point-of-care test and lack of in vivo target values restrict its current use.

Comparative Assessment of APTT Reagents for Evaluating Anticoagulant Sensitivity of Fucosylated Glycosaminoglycans (FGs) Derived from Sea Cucumbers.

Fucosylated glycosaminoglycans (FGs) derived from sea cucumbers exhibit potent intrinsic Xase (iXase) inhibition, anticoagulation, and antithrombosis. Plasma activated partial thromboplastin time (APTT), a widely used screening test worldwide, is crucial for evaluating anticoagulant efficacy. However, the applicability of these commercially available APTT reagents for assessing anticoagulation of FGs remains unreported. In this study, we investigated the disparity between ellagic acid and colloidal silica APTT reagents in evaluating anticoagulation of dHG-5 and dHLFG-4, two depolymerized FGs, and elucidated the underlying rationale. The results demonstrated that dHG-5 and dHLFG-4 exhibited heightened sensitivity to the ellagic acid APTT reagent both in vitro and in vivo, and did not significantly affect the activation of APTT reagents for plasma. In addition, both ellagic acid and colloidal silica APTT reagents inhibited the anti-iXase of dHG-5 and dHLFG-4, and the inhibition of the ellagic acid APTT reagent was less pronounced compared to the colloidal silica APTT reagent. These findings suggest that the reduced impact of the ellagic acid APTT reagent on the anti-iXase activity of dHG-5 and dHLFG-4 is responsible for the increased sensitivity in plasma APTT analysis. This study offers valuable insights into the characteristics of two APTT reagents applied for assessing the anticoagulant activity of FG-related compounds.

Foldable low-cost point-of-care device for testing blood coagulation using smartphones.

Cardiovascular diseases (CVDs) caused by thrombotic events are a significant global health concern, affecting millions of people worldwide. The international normalized ratio (INR) is the most widely used measure of coagulation status, and frequent testing is required to adjust blood-thinning drug dosage, requiring hospital visits and experts to perform the test. Here we present a low-cost and portable smartphone-based device for screening INR levels from whole blood samples at the point of care. Our device uses a 3D printed platform and light-emitting diode backlight modules to create a uniform optical environment, and its foldable design allows for easy transport. Our device also features an algorithm that allows users to acquire and process video of sample flow in a microfluidic channel on their smartphone, providing a cost-effective and convenient option for blood coagulation monitoring at the point of care. We tested the performance of our smartphone-based INR device using both commercially available control samples and clinical human blood samples, demonstrating high accuracy and reliability. Our device has the potential to improve patient outcomes by enabling more frequent monitoring and, as appropriate, dosage adjustments of blood-thinning drugs, providing an affordable and portable option for screening INR levels at the point of care.

VKORC1 mutations in rodent populations of a tropical city-state as an indicator of anticoagulant rodenticide resistance.

Anticoagulant rodenticides are commonly used in rodent control because they are economical and have great deployment versatility. However, rodents with Single Nucleotide Polymorphism (SNP) mutations within the Vkorc1 gene are resistant to the effects of anticoagulant rodenticide use and this influences the effectiveness of control strategies that rely on such rodenticides. This study examined the prevalence of rat SNP mutations in Singapore to inform the effectiveness of anticoagulant rodenticide use. A total of 130 rat tail samples, comprising 83 Rattus norvegicus (63.8%) and 47 Rattus rattus complex (36.2%) were conveniently sampled from November 2016 to December 2019 from urban settings and sequenced at exon 3 of Vkorc1. Sequencing analysis revealed 4 synonymous and 1 non-synonymous mutations in Rattus rattus complex samples. A novel synonymous mutation of L108L was identified and not previously reported in other studies. Non-synonymous SNPs were not detected in the notable codons of 120, 128 and 139 in R. norvegicus, where these regions are internationally recognised to be associated with resistance from prior studies. Our findings suggest that the prevalence of anticoagulant rodenticide resistance in Singapore is low. Continued monitoring of rodenticide resistance is important for informing rodent control strategies aimed at reducing rodent-borne disease transmission.

Assessment of risk factors for deep vein thrombosis associated with natural anticoagulants and fibrinolytic regulatory proteins.

Deep vein thrombosis (DVT) is a critical condition and a potential cause of mortality and morbidity in Africa and worldwide with a high recurrence rate. The study was designed to assess the roles of natural anticoagulants and fibrinolytic regulatory factors in the development of DVT in Sudanese patients. A case-control study was conducted in Omdurman Teaching Hospital, Khartoum State over a period of 1 year. The study enrolled 200 patients diagnosed with DVT and 200 age-matched and gender-matched controls. Demographic data and data on acquired risk factors were collected using a semi-structured questionnaire. Protein C (PC), protein S (PS), antithrombin III (AT-III), thrombin-activable fibrinolysis inhibitor (TAFI), and plasminogen activator inhibitor-1 (PAI-1) were measured in patients and controls. Among the patients with DVT, 5.5% had PC deficiency, 8.5% had PS deficiency, and 3% had AT-III deficiency. Elevated TAFI and PAI-1 levels were demonstrated in 1.5 and 0.5% of patients, respectively. Risk factors for DVT (overweight, surgical history, and family history of DVT) were remarkably higher in patients than in controls. Among the female participants, pregnancy and usage of oral contraceptive pills were the highest associated risk factors for DVT. The findings concluded that the early assessment of risk factors, including the measurements of natural inhibitors, can predict the occurrence of DVT before it is actually detected in patients.

Assessment of thrombin generation in horses using a calibrated automated thrombogram.

BACKGROUND: The amount of thrombin generated reflects the endogenous thrombin potential (ETP), which depends on the balance of pro- and anticoagulant factors. The calibrated automated thrombogram (CAT) allows for the direct measurement of thrombin generation during the clotting process. OBJECTIVES: (1) To describe the results of the CAT assay in horses, (2) to establish intra-assay and intra- and interindividual variation of thrombin generation in healthy horses, and (3) to compare in vitro low-molecular-weight heparin (LMWH) sensitivity between healthy and sick horses. The hypothesis for the last objective is that inhibition of thrombin generation in sick horses requires higher heparin concentrations. METHODS: The plasma of 10 healthy mixed breed horses was used for the determination of normal thrombin generation parameters (lag time, time to peak, peak thrombin concentration, and ETP). Five of the healthy horses were compared with five horses with systemic inflammatory response syndrome (SIRS). In vitro heparin sensitivity was determined using LMWH. RESULTS: The intra-assay variation was small (<5%) for all parameters. Relatively large intra- and interindividual variation were observed in healthy horses. Four of the five sick horses with SIRS had a thrombogram compatible with a hypercoagulable state. The in vitro heparin sensitivity test suggested decreased sensitivity to LMWH in hypercoagulable states. CONCLUSIONS: The CAT assay could detect coagulopathy in horses. In vivo experiments are needed to confirm that it can be used to monitor responses to LMWH therapy.

Cost-effectiveness analysis of treatments for the first episode of catastrophic antiphospholipid syndrome: A study based on the catastrophic antiphospholipid syndrome registry.

BACKGROUND: Treatments for catastrophic antiphospholipid syndrome (CAPS) rose from recommendations and consensus of international experts based on case series or case reports. We aimed to evaluate the treatment scheme with the best cost-effectiveness ratio associated with lower mortality as a high-impact clinical benefit. METHODS: The CAPS Registry was used as our source of structured data on the different therapeutic strategies, their frequency, and their effectiveness (survival). Starting from around 50 different schemes, we identified those with a mortality of less than 33% within the 18 most frequently utilized. After applying the efficiency frontier method, we included two schemes to conduct a cost-effectiveness analysis from the Colombian healthcare sector perspective. Scheme 1 (Glucocorticoids + Anticoagulation + Anti-aggregation + Intravenous IgG immunoglobulin) and scheme 2 (Glucocorticoids + Anticoagulation + Anti-aggregation + Plasma exchange) were compared in terms of costs and survival. Deterministic and probabilistic sensitivity analyses (Monte Carlo simulation) were conducted to evaluate model robustness and uncertainty. RESULTS: Our analysis uses the information corresponding to 427 cases from the CAPS registry, the majority being women (68.8%), with a mean age of 45.7 years and bearing general mortality of 38.17% (female: 38.4%, male: 37.5%). Scheme 2 was the cost-effective strategy over scheme 1. The results were robust on discrete sensitivity analysis and probability sensitivity analysis (Monte Carlo simulation). CONCLUSION: To our knowledge, this is the first economic evaluation focused on the treatment of CAPS. For the Colombian health system, schemes 1 and 2 have similar behavior; nevertheless, scheme 2 represents the best cost-effectiveness ratio. This treatment approach is highly susceptible to the allocation of resources by the system and beneficial in terms of health outcomes.

Assessment of Coagulation and Hemostasis Biomarkers in a Subset of Patients With Chronic Cardiovascular Disease.

Measurement of a single marker of coagulation may not provide a complete picture of hemostasis activation and fibrinolysis in patients with chronic cardiovascular diseases. We assessed retrospective orders of a panel which included prothrombin fragment 1.2 (PF1.2), thrombin: antithrombin complexes, fibrin monomers, and D-dimers in patients with heart assist devices, cardiomyopathies, atrial fibrillation and intracardiac thrombosis (based on ordering ICD-10 codes). During 1 year there were 117 panels from 81 patients. Fifty-six (69%) patients had heart assist devices, cardiomyopathy was present in 17 patients (21%) and 29 patients (36%) had more than 1 condition. PF1.2 was most frequently elevated in patients with cardiomyopathy (61.1%) compared to those with cardiac assist devices (15.7%; P = 0.0002). D-dimer elevation was more frequent in patients with cardiac assist devices (98.8%) compared to those patients with cardiomyopathy (83.3%; P = 0.014). Patients with cardiomyopathy show increases of PF1.2 suggesting thrombin generation. In contrast, elevations of D-dimers without increase in other coagulation markers in patients with cardiac assist devices likely reflect the presence of the intravascular device and not necessarily evidence of hemostatic activation.

Post-acute pre-discharge echocardiography in the long-term prognostic assessment of pulmonary thrombembolism.

The aim of our study was to asses the long-term prognostic impact of post-acute, pre-discharge echocardiographic assessment of right ventricular (RV) dysfunction in patients with low- and intermediate-risk pulmonary embolism (PE). Consecutive patients with acute PE underwent post-acute, pre-discharge echocardiographic assessment of RV dysfunction (defined by: RV dilation, tricuspid anulus peak systolic excursion, or tricuspid regurgitation systolic velocity). A Cox multivariate survival mode was constructed to determine the prognostic impact of post-acute, pred-discharge RV dysfunction on all-cause mortality. 615 patients were included: 330 (54%) women, mean age 64 ± 18 years, 265 (43.1%) with post-acute, predischarge RV dysfunction. During follow-up (median 1068 days), 88 (14.3%) patients died. On Cox multivariate analyis, pre-discharge post-acute tricuspid regurgitation systolic velocity emerged as the only independent echocardiographic predictor of mortality (HR 1.73 for every 1 m/s increase; 95% confidence interval 1.033-2.897; p = 0.037). RV dysfunction persists in almost one half of PE patients in the post-acute phase on pre-discharge echocardiography; however, only tricuspid regurgitation systolic velocity independently predicts long-term prognosis.

Assessment of adherence to cancer-associated venous thromboembolism guideline and pharmacist's impact on anticoagulant therapy.

PURPOSE: Cancer-associated venous thromboembolism (VTE) can cause many unfavorable health outcomes. Many institutions have published guidelines, but implementation of these guidelines in cancer clinics is still under investigation. This study aimed to evaluate the guideline adherence and identify potential gaps between the recommendations and their implications in clinics. METHODS: A prospective study was conducted between September and December 2018 at oncology inpatient and ambulatory settings. The guideline adherence rate was assessed for inpatients during hospital stay by using 8 criteria developed based on the National Comprehensive Cancer Network (NCCN) Guideline on Cancer Associated Venous Thromboembolic Disease Version 1.2018. Guideline-based recommendations were proposed to the consultant physician in case of non-adherence. Khorana risk scores were calculated for each patient at outpatient clinics. In cases where the score was found to be ≥ 3, the consultant physician was informed. RESULTS: A total of 100 inpatients and 200 ambulatory patients were included in the study. The guideline adherence rates ranged between 59 and 100% for 5 out of 8 pre-defined criteria, whereas the rate for others remained at 0-1%. A significant increase was observed in the adherence rates for initiation of prophylaxis at admission and determination of correct dose of an anticoagulant after recommendations being implemented (p < 0.001, McNemar test). Eleven patients were identified as at high-risk of VTE at ambulatory setting; however, an initiation of an anticoagulant was not considered by the consultant physicians. CONCLUSION: There are potential problems in implementation of guideline recommendations, which leads to low adherence rate. Therefore, liason with pharmacists and consultants for individual risk assessment and monitoring of patients will help to increase guideline adherence rates.

Questions and Answers on Practical Thrombotic Issues in SARS-CoV-2 Infection: A Guidance Document from the Italian Working Group on Atherosclerosis, Thrombosis and Vascular Biology.

In patients with coronavirus disease 2019 (COVID-19), the prevalence of pre-existing cardiovascular diseases is elevated. Moreover, various features, also including pro-thrombotic status, further predispose these patients to increased risk of ischemic cardiovascular events. Thus, the identification of optimal antithrombotic strategies in terms of the risk-benefit ratio and outcome improvement in this setting is crucial. However, debated issues on antithrombotic therapies in patients with COVID-19 are multiple and relevant. In this article, we provide ten questions and answers on risk stratification and antiplatelet/anticoagulant treatments in patients at risk of/with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection based on the scientific evidence gathered during the pandemic.

Chondroitin/dermatan sulfate purified from corb (Sciaena umbra) skin and bone: In vivo assessment of anticoagulant activity.

The present work deals with the extraction and purification of chondroitin sulfate/dermatan sulfate from skin (CSG) and bone (CBG) of corb (Sciaena umbra). Electrophoresis of these polymers in barium acetate buffer on cellulose acetate revealed two fractions similar to dermatan sulfate and chondroitin sulfate. The in vivo anticoagulant activity of both chondroitin sulfate/dermatan sulfate (CS/DS) were evaluated, at 25 and 75 mg kg-1 of body weight (b.w), using activated partial thromboplastin time (aPTT), prothrombine time (TT) and thrombin time (PT) tests. Results showed that aPTT of CSG and CBG at 75 mg kg-1 of b.w were prolonged by 1.59 and 1.48-fold respectively, compared with the control. Further, toxicity studies on liver performed by the catalytic activity of transaminases in plasma, oxidative stress markers and hepatic morphological changes demonstrated that CSG and CBG at both doses are not toxics. In summary, the higher activity and lower toxicity of both CS/DS, especially at 25 mg kg-1 of b.w, recommended these compounds as a better drug candidate.

Use of the French healthcare insurance database to estimate the prevalence of exposure to potential drug-drug interactions.

PURPOSE: Drug-drug interactions (DDIs) require monitoring in an aging population with increasing polypharmacy exposure. We aimed to estimate the prevalence of exposure to potential DDIs using the French healthcare insurance system database, for six DDIs with various clinical relevance: angiotensin II receptor blockers or angiotensin-converting enzyme inhibitors and nonsteroidal anti-inflammatory drugs (ARBs-ACEIs + NSAIDs), antiplatelet agents and NSAIDs (AAP + NSAIDs), serotonergic drugs and tramadol (SD + T), statins and macrolides (S + M), oral anticoagulant and NSAIDs (OAC + NSAIDs), and colchicine and macrolides (C + M). METHODS: We used exhaustive healthcare data from a 1/97th random sample of the population covered by the French health insurance system (EGB) between 2006 and 2016. Exposure to a DDI was defined as overlapping exposure to two interacting drugs. The prevalence of exposure was estimated by year. RESULTS: Prevalence of exposure in 2016 was estimated at 3.7% for ARBs-ACEIs + NSAIDs, 1.5% for AAP + NSAIDs, 0.76% for SD + T, 0.36% for S + M, 0.24% for AOC + NSAIDs, and 0.02% for C + M. In 26% to 58% of episodes of exposure, the two interacting drugs were prescribed by the same physician and dispensed by the same pharmacy the same day. Between 2006 and 2016, the yearly prevalence was increasing for SD + T and for DDIs involving NSAIDs, and it was decreasing for those involving macrolides. CONCLUSION: Exposures to potential DDIs in France are not uncommon with a high proportion resulting from a co-prescription by the same physician. Monitoring the prevalence of exposure to DDIs is needed to implement prevention measures. Administrative data enable this surveillance in large and representative cohorts.

Tortuosity-powered microfluidic device for assessment of thrombosis and antithrombotic therapy in whole blood.

Accurate assessment of blood thrombosis and antithrombotic therapy is essential for the management of patients in a variety of clinical conditions, including surgery and on extracorporeal life support. However, current monitoring devices do not measure the effects of hemodynamic forces that contribute significantly to coagulation, platelet function and fibrin formation. This limits the extent to which current assays can predict clotting status in patients. Here, we demonstrate that a biomimetic microfluidic device consisting stenosed and tortuous arteriolar vessels would analyze blood clotting under flow, while requiring a small blood volume. When the device is connected to an inline pressure sensor a clotting time analysis is applied, allowing for the accurate measurement of coagulation, platelets and fibrin content. Furthermore, this device detects a prolonged clotting time in clinical blood samples drawn from pediatric patients on extracorporeal membrane oxygenation receiving anticoagulant therapy. Thus, this tortuosity activated microfluidic device could lead to a more quantitative and rapid assessment of clotting disorders and their treatment.

Application of clot-fibrinolysis waveform analysis to assessment of in vitro effects of direct oral anticoagulants on fibrinolysis.

INTRODUCTION: Acceleration of fibrinolysis by direct oral anticoagulants (DOACs) has been reported by several groups, suggesting contribution of not only anticoagulant but also fibrinolytic effects to the therapeutic efficacy. The present study aims to evaluate the usability of clot-fibrinolysis waveform analysis (CFWA) for assessment of in vitro effects of DOACs on fibrinolysis. METHODS: The experimental conditions were optimized according to how t-PA concentrations and a time length after t-PA adjustment affect parameters of CFWA. Addition of the activated partial thromboplastin time (APTT) reagent followed by that of calcium and t-PA was done to obtain clotting and fibrinolytic reaction curves which were mathematically differentiated for CFWA (APTT-CFWA). The positive and negative modes of waveforms were defined as the direction toward fibrin generation and that toward fibrin degradation, respectively. The maximum positive and negative values (Maxp 1 and Maxn 1) correspond to the maximum coagulation velocity and the maximum fibrinolysis velocity, respectively. Plasma spiked with each of DOACs (rivaroxaban, apixaban, edoxaban, and dabigatran) was subjected to APTT-CFWA. RESULTS: Optimization of t-PA use was based on Maxn 1. Roughly biphasic effects of rivaroxaban and dabigatran but not apixaban or edoxaban on fibrinolysis were observed through Maxn 1 and the fibrinolysis peak time, which was defined as a time length from the time when Maxp 1 (Maxp 1 time) to the time when Maxn 1 appears (Maxn 1 time). CONCLUSION: The results suggest the usability of CFWA for assessment of DOAC effects and provide insights into relevance of anticoagulation to therapeutic efficacy and bleeding risk from the perspective of fibrinolysis.