Coagulation Factor Deficiencies Research Articles

False Prolongation of Activated Partial Thromboplastin Time with Aminoglycoside Antimicrobial Agents: A Case Report

BACKGROUND: Activated partial thromboplastin time (APTT) is a clotting time assay for screening bleeding tendency, evaluating coagulation factor production capacity, assessing preoperatively, monitoring anticoagulant drugs, and searching for blood coagulation abnormalities such as hemophilia and antiphospholipid syndrome. CASE PRESENTATION: Here, we present a 77-year-old male patient with dyspnea who was suspected to have a drug-resistant Pseudomonas aeruginosa infection and pulmonary mycosis. The patient had no history of bleeding tendencies or anticoagulant medication use. The laboratory test results revealed an abnormally prolonged activated partial thromboplastin time (APTT) of 120.3 s using the Coagpia® APTT-N reagent. The APTT test is frequently used to evaluate blood clotting function and assess for bleeding disorders. Prolonged APTT can indicate coagulation factor deficiencies or the presence of certain conditions such as von Willebr and disease, hemophilia, and disseminated intravascular syndrome. However, APTT standardization has not been achieved, causing discrepancies in test results due to variations in the reagents used. The prolonged APTT, in this case, was initially suspected to be caused by contamination or other artifacts, but repeat blood collections and cross-mixing tests revealed the Coagpia® APTT-N reagent as the cause of false prolongation. The reagent was changed to HemosIL SynthASil APTT, which revealed a normal APTT result. The patient had been receiving the aminoglycoside antimicrobial agent tobramycin, and the blood sample taken at the peak tobramycin level demonstrated the longest APTT time. The APTT shortened over time, corresponding to the decrease in tobramycin blood levels. CONCLUSION: Overall, this paper reports a case of false APTT prolongation due to a specific APTT reagent in the presence of aminoglycoside antimicrobial agents. The findings underscore the difficulties in standar PTT testing and the importance of considering reagent performance characteristics in result interpretations.

Health-related quality of life is impaired in bleeding disorders of unknown cause: results from the Vienna Bleeding Biobank

BackgroundBleeding disorder of unknown cause (BDUC) is a diagnosis of exclusion after extensive investigation of coagulation and platelet function and is commonly seen among patients with mild-to-moderate bleeding disorders. Despite increasing awareness among treating physicians, little is known about the health-related quality of life (HrQoL) in BDUC. ObjectivesTo investigate HrQoL in patients with BDUC in comparison to the general population and patients diagnosed with other established bleeding disorders. MethodsPatients with mild-to-moderate bleeding disorders from the Vienna Bleeding Biobank, a prospective cohort study, were contacted via mail and phone to complete the 36-Item Health Survey Questionnaire form. ResultsIn total, 333/657 (50.7%) patients completed the 36-Item Health Survey Questionnaire. Patients with BDUC (n = 207, 62%) had significantly impaired HrQoL both in physical (47.8 vs 49.2) and mental health parameters (42.9 vs 51.0) compared to the general population (n = 2914, 56% females), which remained after adjustment for sex and age in multivariable linear regression. The impairment in HrQoL, compared to patients with von Willebrand disease, platelet function defects, or mild clotting factor deficiencies, did not prevail after adjustment for age and sex. In patients with BDUC, age and the presence of at least 1 comorbidity were associated with impaired physical health but not sex or bleeding severity. Of all analyzed bleeding symptoms, only joint bleeding was associated with impaired physical health and gastrointestinal bleeding with mental health in BDUC. ConclusionThe impairments in HrQoL in patients with BDUC emphasize the burden of BDUC on mental and physical well-being, encouraging early recognition and better counseling of patients with BDUC.

High prevalence of heavy menstrual bleeding in women with rare bleeding disorders in the Netherlands: retrospective data from the RBiN study

BackgroundHeavy menstrual bleeding (HMB) is associated with a reduced quality of life and limitations in social and physical functioning. Data on HMB in women with rare bleeding disorders (RBDs), including coagulation factor deficiencies and fibrinolytic disorders, are scarce. ObjectivesTo analyze the prevalence, severity, and treatment of HMB in Dutch women with an RBD. MethodsThe Rare Bleeding Disorders in the Netherlands (RBiN) study included 263 patients with an RBD from all 6 hemophilia treatment centers (October 2017-November 2019). In this analysis, data of 111 women aged ≥16 years were studied. According to the International Society on Thrombosis and Haemostasis bleeding assessment tool, HMB symptoms were scored from 0 (no/trivial) to 4 (severe symptoms requiring medical intervention). HMB was defined as a score ≥1. Age at RBD diagnosis was extracted from patient files. ResultsHMB was reported by 80% of women (89/111) and was more prevalent in women with a fibrinolytic disorder (33/35; 94%) than in women with a coagulation factor deficiency (56/76; 74%) (P = .011). Of the 89 women with HMB, 82% (n = 73) ever required treatment. Multiple treatment modalities were frequently used, both in severe and mild deficiencies. Hormonal treatment was mostly used (n = 64; 88%), while antifibrinolytics were prescribed less frequently (n = 18; 25%). In women with HMB since menarche (n = 61; 69%), median age at RBD diagnosis was 28 years (IQR, 14-41). ConclusionHMB is common in women with RBDs. Women with mild deficiencies also frequently reported HMB. Only a minority of women were treated with hemostatic agents. A significant diagnostic delay was observed after the onset of HMB symptoms.

Evaluating Gene Therapy as a Potential Paradigm Shift in Treating Severe Hemophilia.

Hemophilia is characterized by a deficiency in coagulation factors VIII or IX. The general standard of care for severe hemophilia is frequent intravenous recombinant or plasma-derived factor replacement to prevent bleeding. While this treatment is effective in preventing bleeding, frequent infusions are burdensome for patients. Nonadherence to the therapeutic regimen leaves people with hemophilia at risk for spontaneous and traumatic bleeds into joints as well as life-threatening bleeds such as intracranial hemorrhage. The chronicity of the disorder often leads to the formation of target joints, causing long-term pain and impairing mobility. As a monogenic disorder with well-understood genetics, hemophilia is an ideal disorder for implementing innovations in gene therapies. Indeed, recent approvals of two gene therapy products have the potential to shift the hemophilia treatment paradigm. Valoctocogene roxaparvovec and etranacogene dezaparvovec-drlb are gene therapies for hemophilia A and B, respectively. These therapies, given as a single intravenous infusion, may improve patients' quality of life, decreasing treatment burden and resulting in factor expression that virtually eliminates the need for factor replacement. Since both treatments involve viral vectors targeted to the liver, short- and long-term safety and efficacy monitoring involves monitoring liver enzymes to track liver health. Long-term monitoring of efficacy, durability of gene expression, and safety are ongoing. Gene therapy presents a promising new therapeutic option for patients with hemophilia and warrants continued innovation and investigation.

Four Decades of Carrier Detection and Prenatal Diagnosis in Hemophilia A: Historical Overview, State of the Art and Future Directions.

Hemophilia A (HA), a rare recessive X-linked bleeding disorder, is caused by either deficiency or dysfunction of coagulation factor VIII (FVIII) resulting from deleterious mutations in the F8 gene encoding FVIII. Over the last 4 decades, the methods aimed at determining the HA carrier status in female relatives of HA patients have evolved from phenotypic studies based on coagulation tests providing merely probabilistic results, via genetic linkage studies based on polymorphic markers providing more accurate results, to next generation sequencing studies enabling highly precise identification of the causative F8 mutation. In parallel, the options for prenatal diagnosis of HA have progressed from examination of FVIII levels in fetal blood samples at weeks 20-22 of pregnancy to genetic analysis of fetal DNA extracted from chorionic villus tissue at weeks 11-14 of pregnancy. In some countries, in vitro fertilization (IVF) combined with preimplantation genetic diagnosis (PGD) has gradually become the procedure of choice for HA carriers who wish to prevent further transmission of HA without the need to undergo termination of pregnancies diagnosed with affected fetuses. In rare cases, genetic analysis of a HA carrier might be complicated by skewed X chromosome inactivation (XCI) of her non-hemophilic X chromosome, thus leading to the phenotypic manifestation of moderate to severe HA. Such skewed XCI may be associated with deleterious mutations in X-linked genes located on the non-hemophilic X chromosome, which should be considered in the process of genetic counseling and PGD planning for the symptomatic HA carrier. Therefore, whole exome sequencing, combined with X-chromosome targeted bioinformatic analysis, is highly recommended for symptomatic HA carriers diagnosed with skewed XCI in order to identify additional deleterious mutations potentially involved in XCI skewing. Identification of such mutations, which may profoundly impact the reproductive choices of HA carriers with skewed XCI, is extremely important.

A Patient with Severe Fever with Thrombocytopenia Syndrome, Activated Partial Thromboplastin Time Prolongation, and Transient Antiphospholipid Antibodies.

A prolonged activated partial thromboplastin time (APTT) is observed in patients with severe fever with thrombocytopenia syndrome (SFTS) and is one of the risk factors for severe disease. The mechanism underlying a prolonged APTT is largely unknown. The presence of antiphospholipid (aPL) antibodies in various viral infections has been documented but never reported in a patient with SFTS. We herein report the first SFTS patient with APTT prolongation and concurrent transiently positive aPL antibodies (lupus anticoagulants and anticardiolipin antibodies) with no coagulation factor deficiency.

Clinical Profile and Bleeding Outcome of Pediatric Rare Bleeding Disorders: The Royal Hospital’s Experience, Oman

Introduction: Rare Bleeding Disorders (RBDs), a group of inherited coagulation factor deficiencies, are more common in areas with a high rate of consanguineous marriages. Data on the frequency and outcome of RBDs among children in Oman are limited. Aim: This study evaluated the clinical profile and bleeding outcomes of paediatric RBDs at the Royal Hospital, the largest referring centre in Oman, from 2010 to 2020. Methods: This retrospective descriptive cohort study includes all Omani children, less than 13 years of age, diagnosed with RBDs, and followed at the Royal Hospital. The patient’s data was retrieved from the electronic chart system. Results: Forty-one patients (24 males and 17 females) were included. Based on factor level at diagnosis, 34(83%) patients have factor VII deficiency, four (9.7%) patients have factor XIII deficiency, one (2.4%) patient has fibrinogen deficiency, and one patient (2.4%) has factor X deficiency. Four (9.4%) patients required blood transfusion for active bleeding, 15(36.6%) patients were treated on demand with tranexamic acid, and 3(7.3%) patients were on regular prophylaxis with tranexamic acid. The mean period of follow-up was 3.15 years. The majority (87.8%) of patients had no active bleeding, and only two (4.9%) patients developed severe bleeding. The mean annual bleeding rate outcome was 0.2, 0.5, and 7 for patients with FVII, FXIII, and FX, respectively. Conclusions: Omani children with rare bleeding disorders are commonly diagnosed incidentally. They usually do not require active treatment because their bleeding outcome is favourable.

Mathematical modelling of gene delivery in patients with haemophilia B

Haemophilia B is a bleeding disorder resulting from a deficiency of coagulation factor IX (FIX). Although gene therapy is a potentially curative treatment option, optimising the dosing of therapeutic genes for patients remains a challenge. Detailed simulation of gene delivery systems is required for an improved understanding of the system. Hence, the purpose of this paper is to develop a modelling framework to predict the physiological response of a subject affected by type B haemophilia to a dose of the vector. To address this, an integrated pharmacokinetic/pharmacodynamic (PK/PD) modelling platform was developed based on in vivo clinical data for three patients with severe haemophilia B, whose functional plasma levels of FIX are less than 1% of the normal value. The plasma FIX activity was considered as the pharmacological effect, while the level of serum alanine aminotransferase (ALT) demonstrated the hepatocellular toxicity. Both an individual-based modelling approach and a population modelling approach were used to estimate the physiological parameters of the developed PK/PD models. The models were then validated using data from the clinical study before being used in a simulation-based modelling approach to provide dosing recommendations. The results obtained from the study demonstrate a good prediction of the pharmacokinetics and pharmacodynamics of the vector. Model-based simulations were subsequently performed to guide initial dose selection to provide clinicians with better tools to simplify the decision-making process for designing more effective treatment plans.

Solvent/detergent treated pooled human plasma can decrease the recurrence of allergic transfusion reactions in pediatric, adolescent, and young adult patients.

Octaplas is a solvent/detergent (S/D)-treated pooled human plasma indicated for the treatment of thrombotic thrombocytopenic purpura (TTP) as well as multiple coagulation factor deficiency in patients with liver disease or undergoing liver transplantation or cardiac surgery. We aimed at providing pediatric, adolescent, and young adult evidence for the decrease in allergic transfusion reactions (ATRs) with S/D-treated plasma. A single-center retrospective review of patient records was performed from January 2018 through July 2022 for patients who received S/D treated plasma (Octaplas™; Octapharma). A total of 1415 units of S/D-treated plasma were transfused to nine patients at our institution. Patient ages ranged from 13 months to 25 years old. The reason to initiate transfusion with S/D treated plasma in six patients was mild to severe ATR to plasma-containing products and the need for therapeutic plasma exchange (TPE) or plasma transfusions (PTs). TPE or PT was performed for various clinical indications. Average S/D treated plasma volume per TPE or PT ranged from 200 to 1800 mL per event. During the study period, since initiating transfusions with S/D treated plasma, there have been no allergic or other transfusion reactions reported among these patients. We have successfully utilized S/D treated plasma over the last 4.5 years for pediatric, adolescent, and young adult patients who otherwise would have suffered ATR due to necessary TPE or PT. S/D treated plasma is an additional tool that can be utilized by transfusion services, including pediatrics, to safely transfuse their patients.

Mesenchymal Stromal Cells Prevent Blood-induced Degeneration of Chondrocytes in a New Model of Murine Hemarthrosis

Hemophilia is a rare congenital bleeding disorder caused by deficiency in coagulation factors VIII or IX, which is treated with prophylactic clotting factor concentrates. Nevertheless despite prophylaxis, spontaneous joint bleedings or hemarthroses still occur. The recurrent hemarthroses lead to progressive degradation of the joints and severe hemophilic arthropathy (HA) in patients with moderate and even mild forms of the disease. In absence of disease modifying treatment to stop or even delay HA progression, we aimed at evaluating the therapeutic potential of mesenchymal stromal cells (MSCs)-based therapy. We first developed a relevant and reproducible in vitro model of hemarthrosis relying on blood exposure of primary murine chondrocytes. We found that 30% whole blood for 4 days allowed to induce the characteristic features of hemarthrosis including low survival of chondrocytes, apoptosis induction, and dysregulation of chondrocyte markers in favor of a catabolic and inflammatory phenotype. We then evaluated the potential therapeutic effects of MSCs in this model using different conditions of coculture. Addition of MSCs improved the survival of chondrocytes when added either during the resolution or the acute phases of hemarthrosis and exerted a chondroprotective effect by enhancing the expression of anabolic markers, and reducing the expression of catabolic and inflammatory markers. We here provide the first proof-of-concept that MSCs may exert a therapeutic effect on chondrocytes under hemarthrosis conditions using a relevant in vitro model, thereby confirming a potential therapeutic interest for patients with recurrent joint bleedings.

Features of preoperative preparation in the treatment of the knee joint in patients with hemophilia

Hemophilia is considered a hematological-orthopedic disease that develops as a result of damage to various anatomical structures of the musculoskeletal system, among which the synovial joints (so-called "target joints") dominate in almost all patients with hemophilia. The purpose of the study was to develop and implement a modern preoperative preparation algorithm for surgical treatment of knee joint pathology in patients with hemophilia. In order to carry out our research, we analyzed 61 cases of hemophilia that were under inpatient and outpatient treatment at the "Kyiv City Clinical Hospital No.9" in the period from 2008 to 2022. Open or arthroscopic knee synovectomy was performed in 22 (36.1%) examined patients of our study. Indications for synovectomy were the presence of hemarthrosis 4–5 times a year or more, presence of deformity and pain syndrome. Total knee arthroplasty was performed in 39 (63.9%) patients. The indication for this operation was the presence of deforming arthrosis of the knee joint with impaired walking and standing function.The expanded algorithm of preoperative preparation included additional instrumental methods of research and calculation of the deficiency of blood coagulation factors, which made it possible to prevent hemorrhagic complications in this category of patients. Operations on patients with hereditary coagulation disorders should be performed under the supervision of hematologists specializing in coagulation disorders and preferably working in specialized centers that have all the necessary resources for the proper diagnosis and treatment of hemophilia. In order to minimize the risks of hemorrhagic complications, we strongly recommend treating such patients with the participation of a multidisciplinary team of specialists, drawing up an individual therapy plan before the operation, and conducting the operation in centers specializing in the treatment of patients with hemophilia. Keywords: orthopedics, hematological and orthopedic diseases, preoperative preparation algorithms.

Clot Waveform Analysis for Hemostatic Abnormalities.

Clot waveform analysis (CWA) observes changes in transparency in a plasma sample based on clotting tests such as activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT). Evidence indicates that not only an abnormal waveform but also peak times and heights in derivative curves of CWA are useful for the evaluation of hemostatic abnormalities. Modified CWA, including the PT with APTT reagent, dilute PT (small amount of tissue factor [TF]-induced clotting factor IX [FIX] activation; sTF/FIXa), and dilute TT, has been proposed to evaluate physiological or pathological hemostasis. We review routine and modified CWA and their clinical applications. In CWA-sTF/FIXa, elevated peak heights indicate hypercoagulability in patients with cancer or thrombosis, whereas prolonged peak times indicate hypocoagulability in several conditions, including clotting factor deficiency and thrombocytopenia. CWA-dilute TT reflects the thrombin burst, whereas clot-fibrinolysis waveform analysis reflects both hemostasis and fibrinolysis. The relevance and usefulness of CWA-APTT and modified CWA should be further investigated in various diseases.

Function-guided selection of salivary antigens from Ornithodoros erraticus argasid ticks and assessment of their protective efficacy in rabbits

The identification of new protective antigens for the development of tick vaccines may be approached by selecting antigen candidates that have key biological functions. Bioactive proteins playing key functions for tick feeding and pathogen transmission are secreted into the host via tick saliva. Adult argasid ticks must resynthesise and replace these proteins after each feeding to be able to repeat new trophogonic cycles. Therefore, these proteins are considered interesting antigen targets for tick vaccine development. In this study, the salivary gland transcriptome and saliva proteome of Ornithodoros erraticus females were inspected to select and test new vaccine candidate antigens. For this, we focused on transcripts overexpressed after feeding that encoded secretory proteins predicted to be immunogenic and annotated with functions related to blood ingestion and modulation of the host defensive response. Completeness of the transcript sequence, as well as a high expression level and a high fold-change after feeding were also scored resulting in the selection of four candidates, an acid tail salivary protein (OeATSP), a multiple coagulation factor deficiency protein 2 homolog (OeMCFD2), a Cu/Zn-superoxide dismutase (OeSOD) and a sulfotransferase (OeSULT), which were later produced as recombinant proteins. Vaccination of rabbits with each individual recombinant antigen induced strong humoral responses that reduced blood feeding and female reproduction, providing, respectively, 46.8%, 45.7%, 54.3% and 31.9% protection against O. erraticus infestations and 0.7%, 3.9%, 3.1% and 8.7% cross-protection against infestations by the African tick, Ornithodoros moubata. The joint protective efficacy of these antigens was tested in a second vaccine trial reaching 58.3% protection against O. erraticus and 18.6% cross-protection against O. moubata. These results (i) provide four new protective salivary antigens from argasid ticks that might be included in multi-antigenic vaccines designed for the control of multiple tick species; (ii) reveal four functional protein families never tested before as a source of protective antigens in ticks; and (iii) show that multi-antigenic vaccines increase vaccine efficacy compared with individual antigens. Finally, our data add value to the salivary glands as a protective antigen source in argasids for the control of tick infestations.

Isolated Prolongation of Activated Partial Thromboplastin Time: Not Just Bleeding Risk!

Activated partial thromboplastin time (aPTT) is a fundamental screening test for coagulation disturbances. An increased aPTT ratio is quite common in clinical practice. How the detection of prolonged activated aPTT with a normal prothrombin time is interpreted is therefore very important. In daily practice, the detection of this abnormality often leads to delayed surgery and emotional stress for patients and their families and may be associated with increased costs due to re-testing and coagulation factor assessment. An isolated, prolonged aPTT is seen in (a) patients with congenital or acquired deficiencies of specific coagulation factors, (b) patients receiving treatment with anticoagulants, mainly heparin, and (c) individuals/patients with circulating anticoagulants. We summarize here what may cause an isolated prolonged aPTT and evaluate the preanalytical interferences. The identification of the cause of an isolated prolonged aPTT is of the utmost importance in ensuring the correct diagnostic workup and therapeutic choices.

Clotting Factor Deficiencies as an Underlying Cause of Abnormal Uterine Bleeding in Women of Reproductive Age: A Literature Review.

Clotting Factor deficiencies are rare disorders with variations in clinical presentation and severity of symptoms ranging from asymptomatic to mild to life-threatening bleeding. Thus, they pose a diagnostic and therapeutic challenge, mainly for the primary health care providers, general practitioners, and gynecologists who are more likely to first encounter these patients. An additional diagnostic challenge arises from the variable laboratory presentations, as PT, PTT, and BT are not always affected. The morbidity is higher among women of reproductive age since Abnormal Uterine Bleeding-specifically Heavy Menstrual Bleeding-is one of the most prevalent manifestations of these disorders, and in some cases of severe deficiencies has led to life-threatening episodes of bleeding requiring blood transfusions or even immediate surgical intervention. Physician awareness is important as, in the case of some of these disorders-i.e., Factor XIII deficiency-prophylactic treatment is available and recommended. Although uncommon, the potential for rare bleeding disorders and for hemophilia carrier states should be considered in women with HMB, after more prevalent causes have been excluded. Currently, there is no consensus on the management of women in these instances and it is reliant on the physicians' knowledge.

Foundations of hemophilia and epidemiology.

Hemophilia, a congenital coagulopathy characterized by a deficiency in coagulation factor VIII (hemophilia A) or factor IX (hemophilia B), results in a tendency of bleeding proportional to the lacking factor. Most bleeds in patients with hemophilia occur in their joints and muscles, and because of these bleeding episodes, patients may end up developing musculoskeletal alterations resulting from hemophilic arthropathy, even receiving hemostatic treatment. The third edition of the World Federation of Hemophilia's Guidelines for the Management of Hemophilia defines 12 principles that encompass all the different types of multidisciplinary care required by people with hemophilia, one of these being clinical and epidemiological research. The expected number of patients with hemophilia across the world has been estimated at 1125 000, most of them undiagnosed, and the total number of patients with severe hemophilia at 418 000 males. Data available from medium and high-income countries show that the prevalence at birth (incidence) and the prevalence of hemophilia differ, which means that patients with hemophilia are at a disadvantage in terms of life expectancy as compared with the general population. In medium-to-high-income countries, the life expectancy disadvantage of patients with hemophilia A and B as compared with the rest of the population is 30% and 24%, respectively. This life expectancy disadvantage is much greater in countries with more limited access to treatments for hemophilia.

Health care costs and resource use of managing hemophilia A: A targeted literature review.

BACKGROUND: Hemophilia A (HA) is a rare, inherited, serious bleeding disorder characterized by a deficiency of blood clotting factor VIII (FVIII). HA is associated with considerable economic burden. OBJECTIVE: To identify, review, and summarize published studies on the health care resource use and costs of managing HA in the United States using a targeted literature review. METHODS: A comprehensive and targeted literature search was conducted in Embase, MEDLINE, and Cochrane Database of Systematic Reviews covering the period 2010 to 2022. We supplemented the search by searching gray literature (relevant abstracts, posters, and presentations of relevant scientific conferences from the past 6 years [2016 to 2022], reference lists, the Institute for Clinical and Economic Review reports, and other sources). Eligibility criteria were developed based on the population, interventions, comparators, and outcomes framework. For comparability, costs were adjusted to 2021 US dollars. RESULTS: A total of 40 publications, including 17 full-text papers, 21 abstracts, and 2 Institute for Clinical and Economic Review reports, met eligibility criteria. Total annual health care costs per patient ranged from $213,874 to $869,940 and are mainly driven by the cost and intensity of prophylaxis with FVIII replacement concentrates, bypassing agents, and, most recently, emicizumab. Generally, we observed substantial heterogeneity in estimated treatment costs for HA, which varied depending on HA severity, treatment type and intensity, age, weight, and inhibitor status. Patients with inhibitors incurred much higher costs, but annual FVIII treatment costs are increasing over time among a subset of adult patients without inhibitors. Only 2 studies reported indirect costs; these were $13,220 and $27,978 annually among patients without and with inhibitors, respectively. Parents of children with HA spent $8,252 on non-mental health services and $258 on mental health services annually. CONCLUSIONS: The annual health care costs of managing HA are substantial and vary widely, depending on the study population definitions and intensity of prophylaxis. Total health care costs are dominated by the cost of prophylaxis. Indirect costs are also important. More robust studies in various settings, subpopulations, and assessing the impact of emerging therapies are required to fully elucidate the changing societal and economic impact, particularly regarding indirect costs and productivity loss for individuals living with HA. DISCLOSURES: Drs Solari and Thornhill are employees of Spark Therapeutics and Roche Group Shareholders. Ms Chen and Drs Cheng and Sullivan are employees of Curta, Inc. Spark Therapeutics paid Curta, Inc., to conduct the literature search. This study was funded by Spark Therapeutics. Spark Therapeutics was involved in the study design, collection, analysis and interpretation of data, article review, and the decision to submit the report for publication. Medical writing support was provided by Ashfield MedComms, an Inizio company.

Vagus nerve stimulation primes platelets and reduces bleeding in hemophilia A male mice

Deficiency of coagulation factor VIII in hemophilia A disrupts clotting and prolongs bleeding. While the current mainstay of therapy is infusion of factor VIII concentrates, inhibitor antibodies often render these ineffective. Because preclinical evidence shows electrical vagus nerve stimulation accelerates clotting to reduce hemorrhage without precipitating systemic thrombosis, we reasoned it might reduce bleeding in hemophilia A. Using two different male murine hemorrhage and thrombosis models, we show vagus nerve stimulation bypasses the factor VIII deficiency of hemophilia A to decrease bleeding and accelerate clotting. Vagus nerve stimulation targets acetylcholine-producing T lymphocytes in spleen and α7 nicotinic acetylcholine receptors (α7nAChR) on platelets to increase calcium uptake and enhance alpha granule release. Splenectomy or genetic deletion of T cells or α7nAChR abolishes vagal control of platelet activation, thrombus formation, and bleeding in male mice. Vagus nerve stimulation warrants clinical study as a therapy for coagulation disorders and surgical or traumatic bleeding.

Towards achieving a haemophilia-free mind.

Towards achieving a haemophilia-free mind.

In Vitro FVIII Encoding Transgenic Mesenchymal Stem Cells Maintain A Successful Coagulation in FVIII- Deficient Plasma Mimicking Hemophilia A.

Hemophilia A is an X-linked recessive bleeding disorder caused by deficiency of plasma coagulation factor VIII (FVIII), and accounts for about 80-85% of patients with hemophilia. Plasma-derived therapies or recombinant factor VIII concentrates and also FVIII mimicking antibodies are used to prevent and treat the bleeding symptoms. Recently, EMA granted a conditional marketing approval for the first gene therapy of Hemophilia A. Aim of this study was to determine the effectiveness of coagulation in correcting FVIII deficiency with FVIII secreting transgenic mesenchymal stem cells (MSC). A lentiviral vector encoding B-domain-deleted Factor VIII cDNA sequence with CD45 R0 truncated (CD45R0t) surface marker was designed to develop a transgenic FVIII expressing primary cell line by transducing MSC. Efficacy and functionality of secreted FVIII from MSCs was assessed with anti- FVIII ELISA, CD45R0t flow cytometry, FVIII Western Blot and Mixing Test analysis in vitro. Results of this study showed that the transgenic MSCs maintain a persistent FVIII secretion. There was no significant difference in FVIII secretion over time, suggesting stable FVIII expression from the MSCs. Functionality of FVIII protein secreted in MSC supernatant was demonstrated by using Mixing Test in coagulation analysis. In the Mixing Test analysis, FVIIIdeficient human plasma products were mixed either with saline control or FVIII-secreted MSC supernatant. Mean FVIII levels of saline control group were 0.41±0.03 IU/dL whereas mean FVIII levels were 25.41±33.38 IU/dL (p<0.01) in FVIII-secreting MSC supernatant mixed group. Mean activated partial thromboplastin time (aPTT) of saline control group was 92.69±11.38 seconds whereas in FVIII-secreting MSC supernatant mixed group, mean aPTT levels were decreased to 38.60±13.38 seconds (p<0.001). Findings of this in vitro study shows a promising new method applicable to treat Hemophilia A. Accordingly, a FVIII secreting transgenic mesenchymal stem cell study will be initiated in FVIII knock-out animal model.