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Proceedings of the National Academy of... Jan 2020Upon activation, fibrinogen forms large fibrin biopolymers that coalesce into clots which assist in wound healing. Limited insights into their molecular architecture,...
Upon activation, fibrinogen forms large fibrin biopolymers that coalesce into clots which assist in wound healing. Limited insights into their molecular architecture, due to the sheer size and the insoluble character of fibrin clots, have restricted our ability to develop novel treatments for clotting diseases. The, so far resolved, disparate structural details have provided insights into linear elongation; however, molecular details like the C-terminal domain of the α-chain, the heparin-binding domain on the β-chain, and other functional domains remain elusive. To illuminate these dark areas, we applied cross-linking mass spectrometry (XL-MS) to obtain biochemical evidence in the form of over 300 distance constraints and combined this with structural modeling. These restraints additionally define the interaction network of the clots and provide molecular details for the interaction with human serum albumin (HSA). We were able to construct the structural models of the fibrinogen α-chain (excluding two highly flexible regions) and the N termini of the β-chain, confirm these models with known structural arrangements, and map how the structure laterally aggregates to form intricate lattices together with the γ-chain. We validate the final model by mapping mutations leading to impaired clot formation. From a list of 22 mutations, we uncovered structural features for all, including a crucial role for βArg'169 (UniProt: 196) in lateral aggregation. The resulting model can potentially serve for research on dysfibrinogenemia and amyloidosis as it provides insights into the molecular mechanisms of thrombosis and bleeding disorders related to fibrinogen variants. The structure is provided in the PDB-DEV repository (PDBDEV_00000030).
Topics: Albumins; Cross-Linking Reagents; Fibrin; Humans; Mass Spectrometry; Models, Structural; Mutation; Protein Conformation; Thrombosis
PubMed: 31924745
DOI: 10.1073/pnas.1911785117 -
Open Medicine (Warsaw, Poland) 2020Congenital dysfibrinogenemia (CD) is a rare hereditary fibrinogen disorder characterized by normal fibrinogen antigen levels associated with lower functional activities....
Congenital dysfibrinogenemia (CD) is a rare hereditary fibrinogen disorder characterized by normal fibrinogen antigen levels associated with lower functional activities. The aim of this study is to analyze the phenotype and genotype of a family of CD. Routine coagulation screening tests were performed on the proband, her parents, and her grandparents. Then, the purified genomic DNA extracted from peripheral blood was amplified by PCR, and Sanger sequencing was performed to further confirm the mutation. The prothrombin time and activated partial thromboplastin time of the proband were normal, thrombin time prolonged, and the activity of fibrinogen (Fg:Ac) decreased significantly, but fibrinogen antigen (Fg:Ag) level was normal. The coagulation function indices of the proband's father and grandfather were similar to her, and the indices of her mother and grandmother were normal. Sequencing results showed that the proband had a heterozygous missense mutation in FGA gene c.92G > A, which caused the mutation of amino acid 31 from glycine to glutamic acid (p.Gly31Glu). Her father had the same heterozygous mutation. In conclusion, the proband suffered from CD. The change of Gly31Glu in A chain due to the c.92G > A heterozygous missense mutation in the FGA gene is the cause of CD in the family. To the best of our knowledge, the mutation site is new and first reported so far.
PubMed: 33336034
DOI: 10.1515/med-2020-0214 -
Scars, Burns & Healing 2023Surgical burn excision (along with skin grafting) carries the risk of blood loss. The use of enzymatic debridement agents such as Nexobrid® has gained increased...
INTRODUCTION
Surgical burn excision (along with skin grafting) carries the risk of blood loss. The use of enzymatic debridement agents such as Nexobrid® has gained increased popularity as an alternative to surgical debridement in the management of burns with its reported benefits of selective burn debridement, minimising blood loss and potentially reducing the need for skin grafting. However, there is limited evidence regarding its effects on bleeding. Currently, the manufacturer declares there is no evidence for increased risk of localised bleeding and its systemic effects upon coagulation are less clear.
METHODS
We present two clinical cases demonstrating the possible effects of Nexobrid® on coagulation and bleeding at the debridement site. Comparisons are drawn with the manufacturers' guidance as well as evaluating the current recommendations of its use.
DISCUSSION
Nexobrid® is a novel therapy and there are few adverse effects reported in the literature. The basis of its appeal is the reduced blood loss at the debridement site and the selectivity it possesses in preserving healthy dermis. However, our cases have demonstrated that haemorrhage can occur and that those using Nexobrid® should be mindful of the potential bleeding risk from varicosities within the burn wound. We have also illustrated that Nexobrid® can be used in patients with pre-existing clotting disorders without requiring the use of blood products. However, we emphasise the importance of haematological support for its safe administration.
LAY SUMMARY
Nexobrid®, a debriding agent that contains enzymes, has been developed as an alternative to surgery which for most surgeons is the traditional method of removing dead tissue following a burn injury. The active agent is bromelain and this is derived from the stems of pineapples. This novel treatment is increasingly being used in the management of middle to deep skin thickness burns and it seems to have a number of benefits such as reducing blood loss, reducing the need for skin grafting as well as being able to treat burns in certain areas of the body that would be technically challenging to remove in the standard fashion. It simply targets the dead tissue leaving viable remnants of the skin that would hopefully allow healing to occur without the need for surgical intervention. Being a relatively new concept, current evidence regarding the safety and value of Nexobrid® continues to develop. In 2020, an agreement guideline outlining best practice with the use of Nexobrid® was published. In this statement, it was advised that caution should be taken when using Nexobrid® in patients who have blood clotting disturbances as this could increase the likelihood of bleeding. However, they did not mention that excessive bleeding can potentially occur with this treatment.We present two clinical cases demonstrating the possible effects of Nexobrid® on the clotting system and bleeding at the application site. Comparisons are drawn with the manufacturers' guidance as well as assessing the current recommendations of its use. We illustrate that Nexobrid® can be safely used in patients with pre-existing clotting disturbances if the correct procedures are performed. We also highlight the potential complication of excessive bleeding if Nexobrid® is used in patients who have co-existing enlarged surface veins along with their burn injury. We feel the guidance should be updated to reflect these findings.
PubMed: 37124159
DOI: 10.1177/20595131231168333 -
Medicine Nov 2022Congenital dysfibrinogenemia (CD) is a rare coagulation system disease that is often treated without unified management. Individualized treatment thereof presents...
A low-dose therapy of fibrinogen supplement during perioperative period of total knee arthroplasty in an asymptomatic man with congenital dysfibrinogenemia: A case report.
RATIONALE
Congenital dysfibrinogenemia (CD) is a rare coagulation system disease that is often treated without unified management. Individualized treatment thereof presents clinicians with great challenges.
PATIENT CONCERNS
A patient who was about to undergo total knee arthroplasty was found to have CD.
DIAGNOSES
Coagulation screening revealed low fibrinogen, prolonged thrombin time, minor prolonged prothrombin time, and normal activated partial thromboplastin time were detected during admission, but no abnormal personal and family history findings were observed. Therefore, CD and hypofibrinogenemia were suspected. The gene sequencing confirmed the diagnosis of CD.
INTERVENTIONS
The patient received plenty and low level of fibrinogen concentrate during 2 perioperative periods, respectively.
OUTCOMES
Successful clinical outcomes were obtained using different treatment strategies.
LESSONS
In contrast to prior case reports, this case illustrates the feasibility of low dosing of fibrinogen supplements within an asymptomatic patient in a selective operation. Changes in the level of fibrinogen and fibrin degradation product are of great importance for individualized treatment after supplementation.
Topics: Humans; Male; Afibrinogenemia; Fibrinogen; Arthroplasty, Replacement, Knee; Hemostatics; Blood Coagulation Disorders; Perioperative Period; Dietary Supplements
PubMed: 36401403
DOI: 10.1097/MD.0000000000031644 -
Acta Obstetricia Et Gynecologica... Jul 2024Pregnant women with a fibrinogen level <2 g/L represent a high-risk group that is associated with severe postpartum hemorrhage and other complications. Women who would...
INTRODUCTION
Pregnant women with a fibrinogen level <2 g/L represent a high-risk group that is associated with severe postpartum hemorrhage and other complications. Women who would qualify for fibrinogen therapy are not yet identified.
MATERIAL AND METHODS
A population-based cross-sectional study was conducted using the UK Obstetric Surveillance System between November 2017 and October 2018 in any UK hospital with a consultant-led maternity unit. Any woman pregnant or immediately postpartum with a fibrinogen <2 g/L was included. Our aims were to determine the incidence of fibrinogen <2 g/L in pregnancy, and to describe its causes, management and outcomes.
RESULTS
Over the study period 124 women with fibrinogen <2 g/L were identified (1.7 per 10 000 maternities; 95% confidence interval 1.4-2.0 per 10 000 maternities). Less than 5% of cases of low fibrinogen were due to preexisting inherited dysfibrinogenemia or hypofibrinogenemia. Sixty percent of cases were due to postpartum hemorrhage caused by placental abruption, atony, or trauma. Amniotic fluid embolism and placental causes other than abruption (previa, accreta, retention) were associated with the highest estimated blood loss (median 4400 mL) and lowest levels of fibrinogen. Mortality was high with two maternal deaths due to massive postpartum hemorrhage, 27 stillbirths, and two neonatal deaths.
CONCLUSIONS
Fibrinogen <2 g/L often, but not exclusively, affected women with postpartum hemorrhage due to placental abruption, atony, or trauma. Other more rare and catastrophic obstetrical events such as amniotic fluid embolism and placenta accreta also led to low levels of fibrinogen. Maternal and perinatal mortality was extremely high in our cohort.
Topics: Humans; Female; Pregnancy; United Kingdom; Adult; Cross-Sectional Studies; Postpartum Hemorrhage; Fibrinogen; Cohort Studies; Afibrinogenemia; Pregnancy Outcome; Infant, Newborn; Postpartum Period
PubMed: 38519441
DOI: 10.1111/aogs.14828 -
BMJ Case Reports Sep 2020A 26-year-old woman was found to have congenital dysfibrinogenaemia after presenting to our hospital with premature rupture of the membranes and vaginal bleeding. Given...
A 26-year-old woman was found to have congenital dysfibrinogenaemia after presenting to our hospital with premature rupture of the membranes and vaginal bleeding. Given the absence of clear guidelines for the management of pregnancy complicated by dysfibrinogenaemia, we followed expert consensus that exists among published works, with some modifications. This case was managed by a multidisciplinary team of obstetrics-gynaecology, haematology and paediatric haematology. Here we review how the patient presented, the investigations that led to the diagnosis and the treatment options.
Topics: Adult; Afibrinogenemia; Antigens; Diagnosis, Differential; Disseminated Intravascular Coagulation; Factor VIII; Female; Fetal Membranes, Premature Rupture; Fibrinogen; Hemoglobins; Humans; Infusions, Intravenous; Leukocyte Count; Medical History Taking; Multiple Myeloma; Partial Thromboplastin Time; Pregnancy; Prothrombin Time; Thrombin Time; Treatment Outcome; Uterine Hemorrhage
PubMed: 32948529
DOI: 10.1136/bcr-2020-235961 -
Frontiers in Medicine 2023Inherited or acquired molecular abnormalities form a clinically heterogeneous group of fibrinogen disorders called dysfibrinogenaemia. Apart from a pediatric case report...
INTRODUCTION
Inherited or acquired molecular abnormalities form a clinically heterogeneous group of fibrinogen disorders called dysfibrinogenaemia. Apart from a pediatric case report and in contrast to other clinical conditions, acquired dysfibrinogenaemia has not been previously reported in septic patients.
METHODS
In an observational cohort study, 79 adult septic patients were investigated for the presence of acquired dysfibrinogenaemia at the time of their admission to the intensive care unit (ICU) of the University Hospital Frankfurt. Following established recommendations, fibrinogen clotting activity vs. antigen ratios were analyzed using Clauss fibrinogen, prothrombin-derived fibrinogen, and radial immunodiffusion (RID) fibrinogen concentration.
RESULTS
Prothrombin-derived fibrinogen levels were highest (527 ± 182 mg/dL) followed by Clauss fibrinogen (492 ± 209 mg/dL) and radial immunodiffusion fibrinogen (426 ± 159 mg/dL). Very few cases demonstrated hypofibrinogenaemia making overt disseminated intravascular coagulation (DIC) unlikely in the cohort investigated. Clauss/RID fibrinogen ratios were lower (1.17 ± 0.19) compared to prothrombin time-derived/RID ratios (1.35 ± 0.33). Using the Clauss/RID dataset, 21% of patients (16/76 patients) demonstrated values below a threshold ratio for suspected acquired dysfibrinogenaemia arbitrarily set at 1.0. In contrast, prothrombin-derived ratios were below the threshold in only 7% (4/58 patients).
DISCUSSION
The results point to the presence of acquired dysfibrinogenaemia in part of adult septic patients. If confirmed in further studies, this may form part of a specific laboratory signature of a sepsis-associated coagulation phenotype.
PubMed: 38152302
DOI: 10.3389/fmed.2023.1294301 -
International Journal of Molecular... Nov 2023Variant identification underlying inherited dysfibrinogenemia quite exceptionally fails. We report on two dysfibrinogenemia cases whose underlying DNA variant could not...
Variant identification underlying inherited dysfibrinogenemia quite exceptionally fails. We report on two dysfibrinogenemia cases whose underlying DNA variant could not be identified by Sanger analysis. These failures result from two distinct mechanisms. The first case involved raw signal overcorrection by a built-in software, and the second constituted the first description of mosaicism for one of the fibrinogen genes. This mosaicism was subsequently identified by next-generation sequencing reanalysis of the sample.
Topics: Humans; Mosaicism; Afibrinogenemia; Mutation, Missense; Algorithms; Mutation
PubMed: 38068874
DOI: 10.3390/ijms242316551 -
Life (Basel, Switzerland) Mar 2021Diagnosis of rare bleeding disorders is challenging and there are several differential diagnostics issues. Next-generation sequencing (NGS) is a useful tool to overcome...
Resolving Differential Diagnostic Problems in von Willebrand Disease, in Fibrinogen Disorders, in Prekallikrein Deficiency and in Hereditary Hemorrhagic Telangiectasia by Next-Generation Sequencing.
Diagnosis of rare bleeding disorders is challenging and there are several differential diagnostics issues. Next-generation sequencing (NGS) is a useful tool to overcome these problems. The aim of this study was to demonstrate the usefulness of molecular genetic investigations by summarizing the diagnostic work on cases with certain bleeding disorders. Here we report only those, in whom NGS was indicated due to uncertainty of diagnosis or if genetic confirmation of initial diagnosis was required. Based on clinical and/or laboratory suspicion of von Willebrand disease (vWD, = 63), hypo-or dysfibrinogenemia ( = 27), hereditary hemorrhagic telangiectasia (HHT, = 10) and unexplained activated partial thromboplastin time (APTT) prolongation ( = 1), NGS using Illumina platform was performed. Gene panel covered 14 genes (, , , , , , , , , , , , and ) selected on the basis of laboratory results. We identified forty-seven mutations, = 29 (6 novel) in vWD, = 4 mutations leading to hemophilia A, = 10 (2 novel) in fibrinogen disorders, = 2 novel mutations in HHT phenotype and two mutations (1 novel) leading to prekallikrein deficiency. By reporting well-characterized cases using standardized, advanced laboratory methods we add new pieces of data to the continuously developing "bleeding disorders databases", which are excellent supports for clinical patient management.
PubMed: 33807613
DOI: 10.3390/life11030202 -
Frontiers in Neurology 2024Congenital dysfibrinogenemia (CD) is a rare hereditary coagulation disorder resulting from mutations in fibrinogen genes. CD primarily presents with bleeding symptoms,...
BACKGROUND
Congenital dysfibrinogenemia (CD) is a rare hereditary coagulation disorder resulting from mutations in fibrinogen genes. CD primarily presents with bleeding symptoms, but it can also lead to thrombotic events, including ischemic stroke.
CASE PRESENTATION
This report describes the case of a 52-year-old Chinese man who was admitted to the hospital twice due to recurrent cerebral infarction, characterized by sudden speech impairment and weakness in the right upper extremity. Brain MRI revealed multiple ischemic changes, predominantly in the left frontal and parietal lobes. Coagulation tests demonstrated reduced plasma fibrinogen (Clauss method), prolonged prothrombin time and thrombin time, and an elevated international normalized ratio. However, the ELISA assay indicated elevated levels of fibrinogen γ-chain protein. Despite a 2-month-old treatment regimen with aspirin, clopidogrel, and atorvastatin after the first hospitalization, the patient experienced a second ischemic stroke. Genetic analysis using whole-exome sequencing (WES) and Sanger sequencing identified a rare heterozygous missense variation, c.952G>A (rs267606810), in both the stroke patient and his asymptomatic sister. Both individuals exhibited the same alterations in fibrinogen, characterized by reduced functional levels but increased antigenic protein. Subsequently, the patient was diagnosed with ischemic stroke associated with congenital dysfibrinogenemia.
CONCLUSION
This case report expands the clinical phenotype spectrum associated with c.952G>A (rs267606810) and underscores the significance of considering CD as a potential etiology for unexplained ischemic stroke, particularly in patients with a family history of coagulation disorders.
PubMed: 38327620
DOI: 10.3389/fneur.2024.1272802