Inherited abnormalities of coagulation: hemophilia, von Willebrand disease, and beyond

Progress and future prospects of hemostatic materials based on nanostructured clay minerals

The occurrence of uncontrolled hemorrhage is a significant threat to human life and health. Although hemostatic materials have made remarkable advances in the biomaterials field, it remains a challenge to develop safe and effective hemostatic materials for global medical use. Natural clay minerals (CMs) have long been used as traditional inorganic hemostatic agents due to their good hemostatic capability, biocompatibility and easy availability. With the advancement of science, technology and ideology, CM-based hemostatic materials have undergone continuous innovations by integrating new inspirations with conventional concepts. This review systematically summarizes the hemostatic mechanisms of different natural CMs based on their nanostructures. Moreover, it also comprehensively reviews the latest research progress for CM-based hemostatic hybrid and nanocomposite materials, and discusses the challenges and developments in this field.

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.

Inherited coagulation disorders in Turkish children: A retrospective, single-center cohort study

OBJECTIVE

This study aims to investigate the distribution, clinical characteristics and outcome of inherited coagulation disorders (ICD) in Turkish children.

SUBJECTS AND METHODS

Data from all children (age<18 years) with ICD examined in our center were retrospectively reviewed.

RESULTS

There were 403 children with ICD (233 males and 170 females) with a median age of four years at diagnosis. The percentages of von Willebrand disease (vWd), hemophilia and rare bleeding disorders (RBD) were 40 %, 34 % and 26 %, type-1, type-2 and type-3 vWd were 63 % 17 % and 20 %, hemophilia A and B were 84 % and 16 %, and severe, moderate and mild hemophilia were 48 %, 30 % and 22 %, respectively. Factor VII and FXI deficiencies were the most prevalent, comprising 56 % and 22 % of all children with RBD, respectively. Parental consanguinity rates were 72 % in type-3 vWd and 61 % in severe RBD. The overall prevalence of gastrointestinal bleedings was 4.5 % (18/403), intracranial bleeding (ICB) was 4.96 % (20/403), mortality from ICB was 30 % (6/20) and the overall mortality rate was 1.49 % (6/403). No life-threatening bleeding was seen during regular prophylaxis. Chronic arthropathy prevalence in severe hemophilia was 8 % with primary prophylaxis and 53 % with demand therap. Inhibitor prevalence was 14 % in hemophilia-A and 5 % in hemophilia-B.

CONCLUSIONS

These data show that vWd is the most common ICD, type-3 vWd and RBD are prevalent due to frequent consanguineous marriages and diagnosis of ICD is substantially delayed in Turkish children. Prophylactic replacement therapy prevents occurrence of life-threatening bleedings and reduces the development of hemophilic arthropathy.

Valproic Acid-Induced Coagulopathy

BACKGROUND

Valproic acid is one of the most commonly used antiseizure medications. Multiple hematologic abnormalities have been reported with the use of valproic acid, which may be particularly relevant in the perioperative surgical setting. The incidence of these abnormalities and prevalence of periprocedural hemorrhage vary significantly in the published literature. In this article we analyze the prevalence and possible etiology of coagulopathy and hemorrhage in patients receiving valproic acid.

METHODS

A literature search was completed using "VPA," "coagulopathy," and "surgery." The available published data from case reports to large case series were reviewed.

RESULTS

Thrombocytopenia was noted to be the most common laboratory abnormality associated with valproic acid. An association between valproic acid and acquired von Willebrand disease has also been suggested. There are case reports describing bleeding in the setting of hypofibrinogenemia and factor XIII deficiency. Perioperative hemorrhage was reported in pediatric studies of orthopedic procedures, but not in adult cohorts undergoing neurosurgical interventions.

CONCLUSIONS

VPA use can cause thrombocytopenia and other coagulation abnormalities. Rigorous, prospective trials are needed to better assess the association between valproic acid and clinically significant coagulopathy. Until such data are available, physicians need to be aware of the potential risk of bleeding in patients receiving valproic acid. A hemostatic evaluation should be considered in symptomatic patients, and may be considered for patients taking VPA who are scheduled for surgery. If an abnormality is detected, hematologists should be involved to make recommendation on perioperative hemostatic strategy.

Hemophilia A with a Rare Presentation of Hemarthrosis and Arthropathy Involving Multiple Joints in a Young Male Child

Hemophilia A is an X-linked hereditary bleeding disorder that is rarely encountered by most physicians and surgeons in their practice. Patients with mild hemophilia A tend to bleed profusely after surgery or trauma whereas a severe variant may manifest as spontaneous bleeding after minor trauma, mainly into the joints and muscles. However, seldom do we find a case where the patient experiences bleeding into multiple joints at the same time. In the South Asian population, the incidence of hemarthrosis in hemophilic patients holds scarce literature, making this an under-reported entity.

Oral and Psychological Alterations in Haemophiliac Patients

Haemophiliacs are hereditary coagulopathies whose basic anomaly consists of the quantitative or qualitative alteration of one or more plasma proteins in the coagulation system. The objective of this review is to analyse all risk factors, predispositions and alterations to the oral-maxillofacial district in patients with haemophilia. The broader assessment also includes the psychological aspects that could affect the treatment and maintenance of oral conditions. The study takes into consideration all the works in the literature in the last 10 years. Works that present oral, dental and psychological changes in haemophilia patients have been combined. A total of 16 studies were analysed carefully evaluating and explaining all the alterations and risk factors that this disease provides. The aim of the review is to report all the anomalies reported in the literature for these patients, and to direct and update the clinician in the treatment of haemophilia patients.

DIFFERENTIAL DIAGNOSIS OF NON-TRAUMATIC BRAIN HEMORRHAGE WITH ETIOPATHOGENETIS ASSOSIATION

Differential diagnostics of non-traumatic intracerebral hemorrhages is a critical area of scientific research and development in neuroradiology. In modern clinical practice, diagnostics are often limited to anatomical description of pathology without taking into account its etiology and pathogenesis. This paper analyzes the ethiopathogenetic factors underlying non-traumatic intracranial hemorrhages, as well as the potential of tomography in differential diagnosis of intracerebral non-traumatic hemorrhages with regard to localization and prevalence. Additionally, the paper analyzes the most common misinterpretations in the diagnostics of non-traumatic intracerebral hemorrhages, providing examples of pathologies with different etiologic but similar hallmarks in magnetic resonance imaging (MRI) and computed tomography (CT).

Impact of aerobic exercise on haemostatic indices in paediatric patients with haemophilia

This study investigated the impact of aerobic exercise on laboratory assessments of haemostatic activity in boys (5–18 years of age) with haemophilia A (HA) or B (HB), examining the hypothesis that laboratory coagulation parameters temporarily improve with exercise. Thirty subjects meeting eligibility criteria (19 HA; 11 HB; mean age: 12.8 years) were invited to participate. They underwent a replacement factor washout period and were advised against strenuous activity for three days prior to the planned intervention. At study visit, baseline blood samples were drawn prior to exercise on a stationary cycle ergometer, aiming to attain 3 minutes (min) of cycling at 85 % of predicted maximum heart rate. Blood work was repeated 5 min (t5) and 60 min (t60) post exercise completion. Samples were assessed for platelet count (PC), factor VIII activity (FVIII:C), von Willebrand antigen (VWF:Ag), ristocetin cofactor activity (VWF:RCo) and platelet function analysis (PFA-100); maximum rate of thrombus generation (MRTG) in blood was measured via thromboelastography and plasma peak thrombin generation (PTG) via calibrated automated thrombography. Mean duration of exercise was 13.9 (± 2.6) min. On average, t5 samples showed significant elevation, relative to baseline in PC, FVIII:C, VWF:Ag, VWF:RCo and PTG, while FVIII:C, VWF:Ag, VWF:RCo and MRTG were significantly elevated in t60 samples. Within the cohort, participants with severe HA showed no change in FVIII:C levels with exercise. The greatest improvement in haemostatic indices was observed in post-adolescent males with mild-moderate HA, who thus represent the group most likely to benefit from a reduction of bleeding risk in the setting of exercise.

Transarterial Embolization in Maxillofacial Intractable Potentially Life-Threatening Hemorrhage

PURPOSE

Although transarterial embolization (TAE) of vascular lesions with embolizing agents through angiographic catheters has been used for more than 45 years, reports of life-threatening maxillofacial bleeding are relatively rare and have not been updated. The authors review treatment modalities, present their experience of the past 21 years, and suggest a comprehensive algorithm and guidelines for the use of TAE in the treatment of intractable life-threatening maxillofacial hemorrhage.

MATERIALS AND METHODS

This article describes 28 patients treated with TAE for severe bleeding that did not respond to conservative therapies. Of these, 13 had uncontrolled epistaxis, 9 were oncologic patients, 4 were postsurgical patients, and 2 were trauma patients.

RESULTS

Details of patients' medical history, failed conservative therapy administered before TAE, imaging results, and blood vessels involved are presented, as are the TAE procedures and materials used, outcome, and complications. All these are discussed in relation to the available updated literature. All 9 oncologic patients (100%) had been treated with chemotherapy before the uncontrolled bleeding, and 7 also had radiotherapy administered to the maxillofacial region. Continuous anticoagulant therapy also seemed to predict such bleeding episodes. TAE resolved the bleeding in all 28 cases and rapidly in 90% of cases. Only in 3 oncologic cases did continued bleeding require 3 to 4 consecutive TAE sessions and combinations of embolizing agents.

CONCLUSIONS

The reported high rate of success could be the result of careful techniques, appropriate preoperative imaging, highly professional personnel, and intraoperative and perioperative treatments.

Deep sequencing reveals different compositions of mRNA transcribed from the F8 gene in a panel of FVIII-producing CHO cell lines

Coagulation factor VIII (FVIII) is one of the most complex biopharmaceuticals due to the large size, poor protein stability and extensive post-translational modifications. As a consequence, efficient production of FVIII in mammalian cells poses a major challenge, with typical yields two to three orders of magnitude lower than for antibodies. In the present study we investigated CHO DXB11 cells transfected with a plasmid encoding human coagulation factor VIII. Single cell clones were isolated from the pool of transfectants and a panel of 14 clones representing a dynamic range of FVIII productivities was selected for RNA sequencing analysis. The analysis showed distinct differences in F8 RNA composition between the clones. The exogenous F8-dhfr transcript was found to make up the most abundant transcript in the present clones. No correlation was seen between F8 mRNA levels and the measured FVIII productivity. It was found that three MTX resistant, nonproducing clones had different truncations of the F8 transcripts. We find that by using deep sequencing, in contrast to microarray technology, for determining the transcriptome from CHO transfectants, we are able to accurately deduce the mature mRNA composition of the transgene and identify significant truncations that would probably otherwise have remained undetected.

New agents for thromboprotection. A role for factor XII and XIIa inhibition

Blood coagulation is essential for hemostasis, however excessive coagulation can lead to thrombosis. Factor XII starts the intrinsic coagulation pathway and contact-induced factor XII activation provides the mechanistic basis for the diagnostic aPTT clotting assay. Despite its function for fibrin formation in test tubes, patients and animals lacking factor XII have a completely normal hemostasis. The lack of a bleeding tendency observed in factor XII deficiency states is in sharp contrast to deficiencies of other components of the coagulation cascade and factor XII has been considered to have no function for coagulation in vivo. Recently, experimental animal models showed that factor XII is activated by an inorganic polymer, polyphosphate, which is released from procoagulant platelets and that polyphosphate-driven factor XII activation has an essential role in pathologic thrombus formation. Cumulatively, the data suggest to target polyphosphate, factor XII, or its activated form factor XIIa for anticoagulation. As the factor XII pathway specifically contributes to thrombosis but not to hemostasis, interference with this pathway provides a unique opportunity for safe anticoagulation that is not associated with excess bleeding. The review summarizes current knowledge on factor XII functions, activators and inhibitors.

Prenatally Diagnosed Hemophilia in a Newborn: a Case Report

Hemophilia is the most common inherited coagulation disorder, and approximately one-half of patients are diagnosed as newborns. For prenatal diagnosis of hemophilia A, genetic tests are performed using chorionic villi (biopsy PCR chorionic villi sampling [CVS]) at 10 weeks' of gestation. The result in this fetus demonstrated an inversion within intron 1 in part for hemophilia A. This male infant, who was his parents' first offspring, was born after an uneventful pregnancy. An uncle suffered from hemophilia A. This report describes a newborn who was prenatally diagnosed with hemophilia A. The timely diagnosis of hemophilia in a newborn enabled the provision of adequate therapy, which led to a favorable outcome.

Factor XII: a drug target for safe interference with thrombosis and inflammation

Data from experimental animal models revealed an essential role for factor XII (FXII) in thrombotic occlusive diseases. In contrast to other blood coagulation factors, deficiency in the protease is not associated with abnormal bleeding from injury sites (hemostasis) in patients or in animals. Cumulatively, these findings suggest that FXII could be targeted as a new method of anticoagulation that is devoid of bleeding risks. An FXIIa-neutralizing antibody, 3F7, has been developed that inhibited thrombosis in an extracorporeal membrane oxygenation (ECMO) system as efficiently as heparin. However, in sharp contrast to heparin, 3F7 treatment was not associated with an increase in therapy-associated hemorrhage. In this review, we summarize current knowledge of FXII physiology and pharmacology.