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1.
Abnormal fibrinogen with an Aα 16Arg → Cys substitution is associated with multiple cerebral infarctions.
Luo, M, Wei, A, Xiang, L, Yan, J, Liao, L, Deng, X, Deng, D, Cheng, P, Lin, F
Journal of thrombosis and thrombolysis. 2018;(3):409-419
Abstract
We found a heterozygous dysfibrinogenemia caused by a substitution of AαArg16Cys. The proband suffered multiple cerebral infarctions. Routine coagulation tests revealed a prolonged thrombin time. The fibrinogen levels in the functional assays were considerably lower than the levels in the immunological assays. The polymerization of the purified fibrinogen was strongly impaired in the presence of calcium. As previously observed in other heterozygous Aα R16C variants, the release rate and amount of fibrinopeptide A (FPA) were lower in the proband than those in normal controls. Additionally, the release of fibrinopeptide B (FpB) was delayed. The immunoblotting analysis using antibodies against human serum albumin indicated that albumin is bound to Aα R16C. The mass spectrometry analysis showed that the Aα R16C fibrinogen chains appeared in the patient's circulation. The clot structure analysis using scanning electron microscopy (SEM) revealed that the fibrin network was dense and consisted of thin and highly branched fibres. Using overlaid fibrinolytic enzymes in a clot lysis experiment, clot degradation was observed to be delayed. These results indicated that the thrombotic tendency may be ascribed to a fibrinolytic resistance caused by an abnormal clot structure with thin fibres and fibrinogen-albumin complexes.
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2.
Oxidation of proteins: is it a programmed process?
Rosenfeld, MA, Vasilyeva, AD, Yurina, LV, Bychkova, AV
Free radical research. 2018;(1):14-38
Abstract
Proteins represent extremely susceptible targets for oxidants. Oxidative modifications of proteins may bring about violation of their structure and functionality. It implies that the structures of proteins are not infallible in terms of their antioxidant defence. The protection mechanisms in preventing oxidative damages for proteins within cells are mainly related to a large variety of antioxidant enzymatic systems. In contrast, plasma proteins are scarcely protected by these systems, so the mechanism that provides their functioning in the conditions of generating reactive oxygen species (ROS) seems to be much more complicated. Oxidation of many proteins was long considered as a random process. However, the highly site-specific oxidation processes was convincingly demonstrated for some proteins, indicating that protein structure could be adapted to oxidation. According to our hypothesis, some of the structural elements present in proteins are capable of scavenging ROS to protect other protein structures against ROS toxicity. Various antioxidant elements (distinct subdomains, domains, regions, and polypeptide chains) may act as ROS interceptors, thus mitigating the ROS action on functionally crucial amino acid residues of proteins. In the review, the oxidative modifications of certain plasma proteins, such as α2-macroglobulin, serum human albumin, fibrinogen, and fibrin-stabilising factor, which differ drastically in their spatial structures and functions, are analysed. The arguments that demonstrate the possibility of existing hypothetical antioxidant structures are presented. For the first time, the emphasis is being placed on the programmed mechanism of protein oxidation.
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3.
Effects of tibolone on fibrinogen and antithrombin III: A systematic review and meta-analysis of controlled trials.
Bała, M, Sahebkar, A, Ursoniu, S, Serban, MC, Undas, A, Mikhailidis, DP, Lip, GYH, Rysz, J, Banach, M, ,
Pharmacological research. 2017;:64-73
Abstract
Tibolone is a synthetic steroid with estrogenic, androgenic and progestogenic activity, but the evidence regarding its effects on fibrinogen and antithrombin III (ATIII) has not been conclusive. We assessed the impact of tibolone on fibrinogen and ATIII through a systematic review and meta-analysis of available randomized controlled trials (RCTs). The search included PUBMED, Web of Science, Scopus, and Google Scholar (up to January 31st, 2016) to identify controlled clinical studies investigating the effects of oral tibolone treatment on fibrinogen and ATIII. Overall, the impact of tibolone on plasma fibrinogen concentrations was reported in 10 trials comprising 11 treatment arms. Meta-analysis did not suggest a significant reduction of fibrinogen levels following treatment with tibolone (WMD: -5.38%, 95% CI: -11.92, +1.16, p=0.107). This result was robust in the sensitivity analysis and not influenced after omitting each of the included studies from meta-analysis. When the studies were categorized according to the duration of treatment, there was no effect in the subsets of trials lasting either <12months (WMD: -7.64%, 95% CI: -16.58, +1.29, p=0.094) or ≥12months (WMD: -0.62%, 95% CI: -8.40, +7.17, p=0.876). With regard to ATIII, there was no change following treatment with tibolone (WMD: +0.74%, 95% CI: -1.44, +2.93, p=0.505) and this effect was robust in sensitivity analysis. There was no differential effect of tibolone on plasma ATIII concentrations in trials with either <12months (WMD: +2.26%, 95% CI: -3.14, +7.66, p=0.411) or≥12months (WMD: +0.06%, 95% CI: -1.16, +1.28, p=0.926) duration. Consistent with the results of subgroup analysis, meta-regression did not suggest any significant association between the changes in plasma concentrations of fibrinogen (slope: +0.40; 95% CI: -0.39, +1.19; p=0.317) and ATIII (slope: -0.17; 95% CI: -0.54, +0.20; p=0.374) with duration of treatment. In conclusion, meta-analysis did not suggest a significant reduction of fibrinogen and ATIII levels following treatment with tibolone.
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4.
Genetics, diagnosis and clinical features of congenital hypodysfibrinogenemia: a systematic literature review and report of a novel mutation.
Casini, A, Brungs, T, Lavenu-Bombled, C, Vilar, R, Neerman-Arbez, M, de Moerloose, P
Journal of thrombosis and haemostasis : JTH. 2017;(5):876-888
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Abstract
UNLABELLED Essentials Hypodysfibrinogenemia is rarely reported among the congenital fibrinogen disorders. This first systematic literature review led to identification of 51 hypodysfibrinogenemic cases. Diagnosis based only on functional/antigenic fibrinogen ratio may be insufficient. Family studies show an incomplete segregation of mutation with the clinical phenotypes. SUMMARY Background Hypodysfibrinogenemia is a rare disease characterized by decreased levels of a dysfunctional fibrinogen. It shares features with both hypo- and dysfibrinogenemia, although with specific molecular patterns and clinical phenotypes. Objectives To better define the genetics, the diagnosis and the clinical features of hypodysfibrinogenemia. Patients/Methods A systematic literature search led to 167 records. After removal of duplicates, abstract screening and full-text reviewing, 56 molecular and/or clinical studies were analyzed, including a novel FGB missense mutation in a woman with a mild bleeding phenotype. Results A total of 32 single causative mutations were reported, mainly in the COOH-terminal region of the γ or Aα chains at heterozygous or homozygous state. Seven additional hypodysfibrinogenemias were due to compound heterozygosity. The hypofibrinogenemic phenotypes were a result of an impaired assembly or secretion or an increased clearance of the fibrinogen variant, whereas the dysfibrinogenemic phenotype was mainly a result of a defective fibrin polymerization and an abnormal calcium or tPA binding. Among 51 identified index cases, a functional/antigenic fibrinogen ratio < 0.7 had a sensitivity of 86% for the diagnosis of hypodysfibrinogenemia. Eleven patients (22%) were asymptomatic at time of diagnosis, 23 (45%) had a mild bleeding phenotype with mainly obstetrical or gynecologic-related hemorrhage and 22 (43%) had experienced at least one thrombotic event, including 23 venous and eight arterial thromboses. Conclusions This first systematic review on hypodysfibrinogenemia shows the heterogeneity of causative mutations and that misdiagnosis could occur in relation to the functional and antigenic fibrinogen levels. Family studies reveal an incomplete segregation of the mutation with the clinical phenotype.
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Treatment of rare factor deficiencies in 2016.
Peyvandi, F, Menegatti, M
Hematology. American Society of Hematology. Education Program. 2016;(1):663-669
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Abstract
Rare bleeding disorders (RBDs) are a heterogeneous group of coagulation disorders characterized by fibrinogen, prothrombin, factors V, VII, X, XI, or XIII (FV, FVII, FX, FXI, or FXIII, respectively), and the combined factor V + VIII and vitamin K-dependent proteins deficiencies, representing roughly 5% of all bleeding disorders. They are usually transmitted as autosomal, recessive disorders, and the prevalence of the severe forms could range from 1 case in 500 000 for FVII up to 1 in 2-3 million for FXIII in the general population. Patients affected with RBDs may present a wide range of clinical symptoms, varying from mucocutaneous bleeding, common to all types of RBDs to the most life-threatening symptoms such as central nervous system and gastrointestinal bleeding. Treatment of these disorders is mainly based on the replacement of the deficient factor, using specific plasma-derived or recombinant products. In countries where these facilities are not available, bleedings could be managed using cryoprecipitate, fresh frozen plasma (FFP), or virus-inactivated plasma. Minor bleedings could be managed using antifibrinolytic agents. Recently, 2 novel drugs, recombinant FXIIIA and a plasma-derived FX, have been added to the list of available specific hemostatic factors; only prothrombin and FV deficiencies still remain without a specific product. Novel no-replacement therapies, such as monoclonal antibody anti-tissue factor pathway inhibitor, RNA interference, and a bispecific antibody that is an FVIIIa mimetic, enhancing thrombin generation through different mechanisms, were developed for patients with hemophilia and may in the future be a good therapeutic option also in RBDs.
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Baseline and long-term fibrinogen levels and risk of sudden cardiac death: A new prospective study and meta-analysis.
Kunutsor, SK, Kurl, S, Zaccardi, F, Laukkanen, JA
Atherosclerosis. 2016;:171-80
Abstract
BACKGROUND Inflammatory markers such as C-reactive protein (CRP) and interleukin-6 have been linked with an increased risk of sudden cardiac death (SCD), but the relationship between fibrinogen and SCD is uncertain. We aimed to assess the association between fibrinogen and SCD. METHODS Plasma fibrinogen was measured at baseline in a prospective cohort of 1773 men aged 42-61 years free of heart failure or cardiac arrhythmias, that recorded 131 SCDs during 22 years follow-up. Correction for within-person fibrinogen variability was made using data from repeat measurements taken several years apart. RESULTS Fibrinogen was strongly correlated with CRP, weakly correlated with several cardiovascular risk markers, and was log-linearly associated with SCD risk. In analyses adjusted for conventional risk factors, the hazard ratio (HR) (95% CIs) for SCD per 1 standard deviation (SD) higher baseline loge fibrinogen was 1.32 (1.11-1.57). The results remained consistent on further adjustment for alcohol consumption, resting heart rate, and circulating lipids 1.30 (1.09-1.56). The corresponding HRs were 1.80 (1.25-2.58) and 1.74 (1.20-2.52) after correction for within-person variability. HRs remained unchanged on further adjustment for CRP and accounting for incident coronary events. In a meta-analysis of three cohort studies, the fully-adjusted relative risks for SCD per 1 SD higher baseline and long-term fibrinogen levels were 1.42 (1.25-1.61) and 2.07 (1.59-2.69) respectively. The associations were similar for non-SCDs in both cohort analysis and the meta-analysis. Addition of plasma fibrinogen to a SCD risk prediction model containing established risk factors did not significantly improve risk discrimination, but improved the net reclassification. CONCLUSIONS Available data suggest fibrinogen is positively, log-linearly, and independently associated with risk of SCD. Further research is needed to assess the potential relevance of plasma fibrinogen concentrations in SCD prevention.
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Fibrinogen: a journey into biotechnology.
Bratek-Skicki, A, Żeliszewska, P, Ruso, JM
Soft matter. 2016;(42):8639-8653
Abstract
Fibrinogen has been known since the mid-nineteenth century. Although initially its interest had been within the field of physiology over time its study has spread to new disciplines such as biochemistry, colloids and interfaces or biotechnology. First, we will describe the bulk properties of the molecule as well as its supramolecular assembly with different ligands by using different techniques and theoretical models. In the next step we will analyze the interfacial properties, an important topic because fibrinogen is considered to be a major inhibitor of lung surfactants' function at the lining layer of alveoli. The final step will be devoted to its main application in biotechnology. Thus, the adsorption of fibrinogen at solid/electrolyte interfaces and at carrier particles will be discussed. The reversibility of adsorption, fibrinogen molecule orientation, and maximum coverage will be thoroughly discussed. The stability of fibrinogen monolayers formed at these surfaces with respect to pH and ionic strength cyclic changes will also be presented. Based on the physicochemical data, adsorption kinetics and colloid particle deposition measurements, probable adsorption mechanisms of fibrinogen on solid/electrolyte interfaces will be defined.
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Mechanisms of fibrinogen adsorption at solid substrates.
Adamczyk, Z, Bratek-Skicki, A, Żeliszewska, P, Wasilewska, M
Current topics in medicinal chemistry. 2014;(6):702-29
Abstract
The aim of this work was to critically review recent results pertinent to fibrinogen adsorption at solid/electrolyte interfaces with the emphasis focused on a quantitative analysis of these processes in terms of the electrostatic interactions. Accordingly, in the first part, the primary chemical structure of fibrinogen is analyzed. Physicochemical data pertinent to the bulk properties derived from hydrodynamic, dynamic light scattering and micro-electrophoretic measurements aided by theoretical modeling are discussed. Possible conformations and the effective charge distribution over the fibrinogen molecule for various pH an ionic strength are defined, especially the semi-collapsed conformation prevailing at physiological conditions. Adsorption kinetics of fibrinogen at hydrophilic and hydrophobic (polymer modified) substrates determined by various techniques is described. Adsorption at polymeric carrier particles, pertinent to immunological assays, studied in terms of electrokinetic and concentration depletion methods, are also considered. The reversibility of adsorption, fibrinogen molecule orientations and maximum coverages are thoroughly discussed. The stability of fibrinogen monolayers formed at these carrier particles in respect to pH and ionic strength cyclic changes is also discussed. In the final section interactions and deposition of model colloid particles on fibrinogen monolayers are analyzed which allows one to derive valuable information about molecule orientations. Based on the physicochemical data, adsorption kinetics and colloid particle deposition measurements, probable adsorption mechanisms of fibrinogen on solid/electrolyte interfaces are defined.
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Coagulation factor XIII deficiency. Diagnosis, prevalence and management of inherited and acquired forms.
Biswas, A, Ivaskevicius, V, Thomas, A, Oldenburg, J
Hamostaseologie. 2014;(2):160-6
Abstract
The plasma circulating zymogenic coagulation factor XIII (FXIII) is a protransglutaminase, which upon activation by thrombin and calcium cross-links preformed fibrin clots/fibrinolytic inhibitors making them mechanically stable and less susceptible to fibrinolysis. The zymogenic plasma FXIII molecule is a heterotetramer composed of two catalytic FXIII-A and two protective FXIII-B subunits. Factor XIII deficiency resulting from inherited or acquired causes can result in pathological bleeding episodes. A diverse spectrum of mutations have been reported in the F13A1 and F13B genes which cause inherited severe FXIII deficiency. The inherited severe FXIII deficiency, which is a rare coagulation disorder with a prevalence of 1 in 4 million has been the prime focus of clinical and genetic investigations owing to the severity of the bleeding phenotype associated with it. Recently however, with a growing understanding into the pleiotropic roles of FXIII, the fairly frequent milder form of FXIII deficiency caused by heterozygous mutations has become one of the subjects of investigative research. The acquired form of FXIII deficiency is usually caused by generation of autoantibodies or hyperconsumption in other disease states such as disseminated intravascular coagulation. Here, we update the knowledge about the pathophysiology of factor XIII deficiency and its therapeutic options.
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The early use of fibrinogen, prothrombin complex concentrate, and recombinant-activated factor VIIa in massive bleeding.
Fries, D
Transfusion. 2013;:91S-95S
Abstract
BACKGROUND Coagulopathy related to massive bleeding has a multifactorial aetiology. Coagulopathy is related to shock and blood loss including consumption of clotting factors and platelets and hemodilution. Additionally hyperfibrinolysis, hypothermia, acidosis, and metabolic changes affect the coagulation system. The aim of any hemostatic therapy is to control bleeding and minimize blood loss and transfusion requirements. Transfusion of allogeneic blood products as well as the presence of coagulopathy cause increased morbidity and mortality. STUDY DESIGN AND METHODS This paper presents a short review on new treatment strategies of coagulopathy, related to massive blood loss. RESULTS Paradigms are actively changing and there is still shortage of data. However, there is increasing experience and evidence that "target controlled algorithms" using point-of-care monitoring devices and coagulation factor concentrates are more effective compared to transfusion of fresh frozen plasma, independently of the individual clinical situation. CONCLUSION Future treatment of coagulopathy associated with massive bleeding can be based on an individualized point-of-care guided rational use of coagulation factor concentrates such as fibrinogen, prothrombin complex concentrate, and recombinant factor VIIa. The timely and rational use of coagulation factor concentrates may be more efficacious and safer than ratio-driven use of transfusion packages of allogeneic blood products.