Search

Factor XIII (FXIII) is activated by thrombin to form a transglutaminase (FXIIIa) that stabilizes clot formation by the cross-linking of fibrin monomers and antifibrinolytic proteins. Although rare, FXIII deficiency is characterized by variable bleeding manifestations depending on the magnitude of the deficiency. A congenital FXIII deficiency with levels less than 1% can be detected in children who present with prolonged bleeding from the umbilical stump as well as protracted bleeding after trauma. An acquired FXIII deficiency may occur in a number of diseases or clinical situations where FXIII levels and/or its activity are decreased. Patients may also develop a relative deficiency in FXIII as a result of hemorrhage or dilutional changes from transfusions during surgery or trauma and are at increased risk for postoperative bleeding. Genetic studies have identified a wide range of mutations that affect the activity of the FXIII protein but in lieu of molecular genetic analyses, FXIII deficiency can be identified by specific diagnostic assays that measure either the transglutaminase activity of the protein or the levels of the protein and its individual subunits. Replacement therapy has also been shown to increase FXIII levels and reduce bleeding symptoms in patients with congenital FXIII deficiency. This review presents recent findings on the biology of FXIII and the clinical manifestations observed among patients with congenital and acquired FXIII deficiencies., (© 2012 American Association of Blood Banks.)

The transglutaminase-mediated, covalent cross-linking of proteins is an essential step in tissue remodeling after injury. This process provides tissues with extra rigidity and resistance against proteolytic degradation. Plasma coagulation factor XIII (FXIII) is a transglutaminase that promotes cross-linking of the extracellular matrix (ECM) components fibrin and fibronectin to form a provisional matrix in response to tissue damage. However, the functional requirement for this FXIII-mediated cross-linked provisional matrix in adult tissue remodeling remains to be defined. Although it has been proposed that the formation FXIII-mediated fibrin-fibronectin provisional matrix is a critical step for ECM remodeling, we show in an FXIII subunit A-deficient murine model of acute liver injury that the lack of FXIII subunit A did not interfere with collagen reconstruction and resolution after liver injury. Furthermore, FXIIIA deficiency caused significantly increased hepatocyte apoptosis and a delay in hepatocyte regeneration after injury, which were accompanied by a significantly high induction of p53 expression. These findings suggest novel functions of FXIII that the FXIII-mediated covalently cross-linked matrix could promote survival signals for hepatocytes in adult tissue remodeling., (Copyright © 2011 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Phylogenetically conserved serine protease cascades play an important role in invertebrate and vertebrate immunity. The mammalian coagulation system can be traced back some 400 million years and shares homology with ancestral serine proteinase cascades that are involved in, for example, Toll receptor signaling in insects and release of antimicrobial peptides during hemolymph clotting. In the present study, we show that the induction of coagulation by bacteria leads to immobilization and killing of Streptococcus pyogenes bacteria inside the clot. The entrapment is mediated via cross-linking of bacteria to fibrin fibers by the action of coagulation factor XIII (fXIII), an evolutionarily conserved transglutaminase. In a streptococcal skin infection model, fXIII(-/-) mice developed severe signs of pathologic inflammation at the local site of infection, and fXIII treatment of wild-type animals dampened bacterial dissemination during early infection. Bacterial killing and cross-linking to fibrin networks was also detected in tissue biopsies from patients with streptococcal necrotizing fasciitis, supporting the concept that coagulation is part of the early innate immune system.

Coagulation factor XIII (F13) circulates in blood as a heterotetramer composed of an A subunit dimer and a B subunit dimer. It is activated by thrombin and crosslinks fibrin monomers. Congenital F13 deficiency demonstrates a lifelong bleeding tendency, abnormal wound healing, and recurrent miscarriages, and it first manifests as umbilical bleeding after birth. In contrast, secondary F13 deficiencies due to its overconsumption and/or hypobiosynthesis by disseminated intravascular coagulation, major surgery, liver diseases, and other disorders are rather common but rarely complicated with bleeding symptoms. Recently, consultations with physicians who have patients with hemorrhagic-acquired F13 deficiency with anti-F13 inhibitors (acquired hemorrhaphilia 13) have indicated an increase in this disease in Japan. We performed a nationwide survey, supported by the Japanese Ministry of Health, Welfare and Labor and confirmed 21 Japanese cases of this disease with anti-F13 inhibitors. Because neither prolonged clotting times nor reduced platelet counts are observed in patients with this disease, many more cases may have been overlooked. Physicians must be mindful of acquired hemorrhaphilia 13 when seeing such patients and should measure F13 activity. Products containing F13 are effective for hemostasis generally, and immunosuppressive therapy must be started immediately to eradicate anti-F13 antibodies., (© Thieme Medical Publishers.)

Factor XIII (FXIII) is a tetrameric zymogen (FXIII-A (2)B (2)) that is converted into an active transglutaminase (FXIIIa) by thrombin and Ca (2+) in the terminal phase of the clotting cascade. By cross-linking fibrin chains and alpha (2) plasmin inhibitor to fibrin, FXIIIa mechanically stabilizes fibrin and protects it from fibrinolysis. Severe deficiency of the potentially active A subunit (FXIII-A) is a rare but severe hemorrhagic diathesis. Delayed umbilical stump bleeding is characteristic, and subcutaneous, intramuscular, and intracranial bleeding occurs with a relatively high frequency in nonsupplemented patients. In addition, impaired wound healing and spontaneous abortion in women are also features of FXIII deficiency. The extremely rare B subunit deficiency results in milder bleeding symptoms. FXIII concentrate is now available for on-demand treatment and primary prophylaxis. A quantitative FXIII activity assay is recommended as a screening test for the diagnosis of FXIII deficiency. For classification purposes, FXIII-A (2)B (2) antigen in the plasma is first determined, and if decreased, further measurement of the individual subunits is recommended in the plasma and FXIII-A in platelet lysate. Analytical aspects of FXIII activity and antigen assays are discussed in this article. There are no hot-spot mutations in the F13A1 and F13B genes, and the majority of causative mutations are missense/nonsense point mutations.

Inherited factor XIII (FXIII) deficiency is a rare bleeding disorder that can present with umbilical bleeding during the neonatal period, delayed soft tissue bruising, mucosal bleeding and life-threatening intracranial haemorrhage. FXIII deficiency has also been associated with poor wound healing and recurrent miscarriages. FXIII plays an integral role in haemostasis by catalysing the cross-linking of fibrin, platelet membrane and matrix proteins throughout thrombus formation, thus stabilizing the blood clot. The molecular basis of FXIII deficiency is characterized by a high degree of heterogeneity, which contributes to the different clinical manifestations of the disease. There have been more than 60 FXIII mutations identified in the current literature. In addition, single nucleotide polymorphisms have been described, some of which have been shown to affect FXIII activity, contributing further to the heterogeneity in patient presentation and severity of clinical symptoms. Although there is a lifelong risk of bleeding, the prognosis is excellent when current prophylactic treatment is available using cryoprecipitate or plasma-derived FXIII concentrate.

Factor XIII (FXIII) is a proenzyme of plasma transglutaminase consisting of enzymatic A (FXIII-A) and noncatalytic B subunits (FXIII-B), and acts in hemostasis and wound healing. We freshly generated mice lacking either FXIII-A or FXIII-B to investigate the physiological functions of FXIII in vivo. Mice carrying the disrupted allele were born at the expected Mendelian ratios, and the homozygous mice were viable and fertile under specific pathogen-free conditions. Although all homozygous and heterozygous mice showed no marked difference from the wild-type animals in general appearance, homozygous mice of either FXIII-A- or FXIII-B-deficiency did have prolonged bleeding times. It was confirmed that thrombin-dependent amine incorporation and fibrin-crosslinking in plasma were undetectable in the FXIII-A-deficient mice and markedly reduced in the FXIII-B-deficient mice; however, the gene expression of each subunit was regulated independently. Recombinant human FXIII-B (rFXIII-B) was expressed in a baculovirus expression system. When rFXIII-B was injected into FXIII-B-deficient mice, FXIII-A levels, fibrin crosslinking, and amine-incorporation activities increased in their plasma, indicating that FXIII-B assisted the maintenance of FXIII-A levels in the circulation. These mouse strains will be useful in exploring the possible pathophysiological roles of each subunit in vivo.

Background: In patients with Henoch-Schoenlein purpura (HSP), particularly with severe gastrointestinal symptoms, an associated decrease of plasma factor XIII has been observed., Patient: The authors report a case of HSP in a boy and describe the development of factor XIII activities throughout the course of the disease. Every relapse of severe gastrointestinal manifestation was associated with a decrease of factor XIII. No improvement was seen after treatment with prednisone. The symptoms resolved each time factor XIII concentrate was administered. With the return of factor XIII to normal values eight weeks after admission abdominal symptoms ceased., Conclusion: The documented course supports the hypothesis that factor XIII activity correlates well with the severity of abdominal symptoms. Measuring factor XIII activity helps to identify those patients with severe gastrointestinal manifestation who may benefit from substitution therapy.

Background: Identification of key molecular players in myocardial healing could lead to improved therapies, reduction of scar formation, and heart failure after myocardial infarction (MI). We hypothesized that clotting factor XIII (FXIII), a transglutaminase involved in wound healing, may play an important role in MI given prior clinical and mouse model data., Methods and Results: To determine whether a truly causative relationship existed between FXIII activity and myocardial healing, we prospectively studied myocardial repair in FXIII-deficient mice. All FXIII(-/-) and FXIII(-)(/+) (FXIII activity <5% and 70%) mice died within 5 days after MI from left ventricular rupture. In contradistinction, FXIII(-/-) mice that received 5 days of intravenous FXIII replacement therapy had normal survival rates; however, cardiac MRI demonstrated worse left ventricular remodeling in these reconstituted FXIII(-/-) mice. Using a FXIII-sensitive molecular imaging agent, we found significantly greater FXIII activity in wild-type mice and FXIII(-/-) mice receiving supplemental FXIII than in FXIII(-/-) mice (P<0.05). In FXIII(-/-) but not in reconstituted FXIII(-/-) mice, histology revealed diminished neutrophil migration into the MI. Reverse transcriptase-polymerase chain reaction studies suggested that the impaired inflammatory response in FXIII(-/-) mice was independent of intercellular adhesion molecule and lipopolysaccharide-induced CXC chemokine, both important for cell migration. After MI, expression of matrix metalloproteinase-9 was 650% higher and collagen-1 was 53% lower in FXIII(-/-) mice, establishing an imbalance in extracellular matrix turnover and providing a possible mechanism for the observed cardiac rupture in the FXIII(-/-) mice., Conclusions: These data suggest that FXIII has an important role in murine myocardial healing after infarction.

Transglutaminases are at least 9 enzymes which cross-link a number of proteins. This type of reaction not only enhances the original functions of substrate proteins, but also adds new functions to them. Factor XIII (FXIII) is a plasma transglutaminase circulating in blood as a heterotetramer and consisting of two catalytic A subunits and two non-catalytic B subunits. It is a proenzyme activated by thrombin in the blood coagulation cascade. It plays an important role(s) in hemostasis, wound healing, and maintenance of pregnancy. Accordingly, a lifelong bleeding tendency as well as abnormal wound healing and recurrent spontaneous miscarriage are common symptoms of FXIII deficiency. Genetic and molecular mechanisms of congenital deficiencies have been analyzed in vitro. The mechanisms of these defects have also been studied in detail by using FXIII gene knock-out mice in vivo. We analyzed eight successful outcomes of pregnancy in patients with congenital deficiency of FXIIIA, in which the plasmatic level of maternal FXIIIA and/or the precise substitute therapies were mentioned. Then we propose the following guidelines for the perinatal management: (i) decidual bleeding usually begins from 5 weeks of gestation and spontaneous abortion always occurs subsequently without substitute therapy; (ii) the plasma level of FXIIIA must be at least 2 approximately 3%, however, if possible, higher than 10% to prevent bleeding and miscarriage; (iii) the administration of 250 IU of FXIIIA concentrate each 7 days is enough to keep the level of plasma FXIIIA more than 10% in the early gestation, however 500 IU each 7 days is adequate in the later period to keep that level; (iv) during labor, the desired level is higher than 20%, if possible, higher than 30% to avoid any risk of strong obstetrical bleeding.

Coagulation factor XIII (FXIII) is a transglutaminase that catalyzes crosslink formation in fibrin clots. Endothelial cells (EC) were demonstrated to bind FXIII via their alpha(v)beta3 integrin receptor. FXIII was also shown to bind platelet glycoprotein IIb/IIIa receptor. In the present study, we analyzed if FXIII can mediate platelet-EC interaction. Both FXIII and activated FXIII (FXIIIa) bound to EC monolayers; this binding was enhanced by the addition of Mn2+ and was inhibited by the monoclonal antibody L609 against alpha(v)beta3 integrin. Normal washed platelets also bound surface-immobilized or soluble FXIII and FXIIIa, and the binding was GPIIb/IIIa dependent. The effect of FXIII concentrate (Fibrogammin-P) treatment on the interaction of ECs with platelets from six FXIII-deficient patients was studied. Patients' platelets were radiolabeled with 3H-Adenine, washed, resuspended in autologous plasma and allowed to adhere to immortalized EC line EAhy926. Adhesion of platelets from FXIII-deficient patients to ECs increased 1.7+/-0.4-fold (P=.01) following intravenous infusion of FXIII concentrate. Similarly, addition of 1 U/ml of FXIII concentrate to the patients' PRP in vitro increased the adhesion 1.8+/-0.5-fold (P=.008). Preincubation of the EC monolayers with increasing concentrations of either FXIII or FXIIIa augmented the adhesion of normal washed platelets to ECs in a dose-dependent manner. At 10 U/ml of EC-bound FXIII or FXIIIa, platelet adhesion enhanced 1.7+/-0.25-fold (P=.03) and 2.5+/-0.5-fold (P=.02), respectively. The increase in platelet adhesion was completely abolished by pretreatment of ECs with the anti-alpha(v)beta3 antibody L609 or by preincubation of the platelets with the GPIIb/IIIa inhibitor Abciximab. Taken together, our data indicate that FXIII mediates the interaction of platelets with ECs by bridging between endothelial alpha(v)beta3 and platelet GPIIb/IIIa integrins. This interaction may be relevant for tissue remodeling and wound repair after vascular injury in FXIII-deficient patients.

Severe homozygous factor XIII deficiency was first described in Switzerland, in 1961. At present 14 patients are known here. Nine are of Swiss origin, the others are immigrants from eastern Europe. A 27-year-old woman with many haemorrhages during childhood immigrated to Switzerland and went through four episodes of haemorrhagic corpus luteum cyst rupture with life-threatening blood loss into the abdomen and three haemorrhages into the retroperitoneal muscles causing sensomotoric palsies, before the diagnosis was established. A monthly prophylactic replacement therapy of 500 IE factor XIII concentrate was started. Since then no signs of haemorrhage occurred. For the last trimester of pregnancy treatment intervals were shortened and dosage increased. Haemorrhage from the umbilical cord for weeks, subcutaneous haematomas, intracranial haemorrhage, muscle haemorrhage and wound bleeding with impaired wound healing as well as tendency to marked scar formation are characteristic for severe homozygous factor XIII deficiency. Without replacement therapy women suffer from obligate abortion. Diagnosis is made by the solubility of fibrin clots in urea (5 mol/l) or monochloroacetic acid (1-2%). For confirmation and monitoring of replacement therapy a quantitative incorporation assay is used. Replacement therapy is necessary in case of haemorrhage, injury, and surgery. Because of the high risk of intracranial haemorrhage prophylaxis is strongly recommended.

The characterization of naturally occurring mutations is one way to approach functionally significant domains of polypeptides. About 10 mutations have been reported in factor XIII (FXIII) A-subunit deficiency, but very little is known about the effects of the mutations on the expression or the structure of this enzyme. In this study, the recent crystallization of FXIII A-subunit and determination of the three-dimensional model were used for the first time to pursue the structural consequences of mutations in the A-subunit. The molecular analysis of four families from Sweden, Germany, and Denmark revealed four previously unreported point mutations. Three of the mutations were missense mutations, Arg326-->Gln, Arg252-->Ile, and Leu498-->Pro, and one was a nonsense mutation, a deletion of thymidine in codon for Phe8 resulting in early frameshift and premature termination of the polypeptide chain. In the case of the nonsense mutation, delT Phe8, the steady-state mRNA level of FXIII A-subunit was reduced, as quantitated by reverse transcriptase-polymerase chain reaction and solid-phase minisequencing. In contrast, none of the missense mutations affected mRNA levels, indicating the possible translation of the mutant polypeptides. However, by enzyme-linked immunosorbent analysis and immunofluorescence, all the patients demonstrated a complete lack of detectable factor XIIIA antigen in their platelets. In the structural analysis, we included the mutations described in this work and the Met242-->Thr mutation reported earlier by us. Interestingly, in the three-dimensional model, all four missense mutations are localized in the evolutionarily conserved catalytic core domain. The substitutions are at least 15 A away from the catalytic cleft and do not affect any of the residues known to be directly involved in the enzymatic reaction. The structural analyses suggest that the mutations are most likely interfering with proper folding and stability of the protein, which is in agreement with the observed absence of detectable FXIIIA antigen. Arg326, Arg252, and Met242 are all buried within the molecule. The Arg326-->Gln and Arg252-->Ile mutations are substitutions of smaller, neutral amino acids for large, charged residues. They disrupt the electrostatic balance and hydrogen-bonding interactions in structurally significant areas. The Met242-->Thr mutation is located in the same region of the core domain as the Arg252-->Ile site and is expected to have a destabilizing effect due to an introduction of a smaller, polar residue in a tightly packed hydrophobic pocket. The substitution of proline for Leu498 is predicted to cause unfavorable interatomic contacts and a disruption of the alpha-helix mainchain hydrogen-bonding pattern; it is likely to form a kink in the helix next to the dimer interface and is expected to impair proper dimerization of the A-subunits. In the case of all four missense mutations studied, the knowledge achieved from the three-dimensional model of crystallized FXIII A-subunit provides essential information about the structural significance of the specific residues and aids in understanding the biologic consequences of the mutations observed at the cellular level.

Congenital factor XIII deficiency is a rare disease, but has provided valuable information on the physiological role of factor XIII and the benefit of factor XIII replacement therapy. It could be shown that not only homozygous patients but also heterozygotes are at risk for bleeding complications. Acquired factor XIII deficiency, however, is much more common, and preliminary studies suggest a lack of factor XIII to be an important feature of various diseases. In acute states and severe hemorrhages, replacement therapy with factor XIII concentrates is recommended. Recent progress in assay methods and future clinical studies should help to evaluate the therapeutic potential of factor XIII.

We report a new case of severe bleeding diathesis due to an acquired inhibitor of fibrin crosslinking. The patient, an 80-year-old woman, was admitted to the hospital for a massive subcutaneous hematoma, with severe anemia requiring red cell transfusion; a subsequent retroperitoneal hematoma developed 2 weeks later. Coagulation studies were normal except for a thromboelastographic pattern suggestive of FXIII deficiency. Clot solubility test was abnormal even after 1:1 mix with normal plasma. Immunochemical studies confirmed the presence of a monoclonal IgG lambda inhibitor directed against FXIII activity (type II FXIII inhibitor). The patient IgG fraction selectively inhibited FXIII transamidating activity but did not inhibit the thrombin-mediated activation of FXIII. The patient was treated with high doses of FXIII concentrate to overcome the inhibitor and immunosuppressive therapy with cyclophosphamide and discharged in good conditions. High doses of commercially available FXIII appear to be a safe and effective method of controlling acute episodes of bleeding in patients with acquired FXIII deficiency.

Factor XIII (XIII), an enzyme found in plasma (present as a pro-enzyme), platelets and monocytes, is essential for normal haemostasis. It may also have a role to play in the processes of wound healing and tissue repair. Inherited XIII deficiency results in a life-long, severe bleeding diathesis which, if untreated, carries a very high risk of death in early life from intracranial bleeding. XIII is a zymogen requiring thrombin and calcium for activation. In plasma, XIII has two subunits: the 'a' subunit, which is the active enzyme, and the 'b' subunit which is a carrier protein. Activated XIII modifies the structure of clot by covalently crosslinking fibrin through an epsilon (gamma-glutamyl)lysine link. It also crosslinks other proteins, including fibronectin and alpha-2-plasmin inhibitor (alpha-2PI), into the clot through the same link. Clot modified by XIII is physically stronger, relatively more resistant to fibrinolysis and may be a more suitable medium for the ingrowth of fibroblasts. Inheritance of factor XIII is autosomal recessive. The majority of patients with the inherited defect show no XIII activity and absence of 'a' subunit protein in plasma, platelets and monocytes. At the molecular level, the defect is not a major gene rearrangement or deletion, but most likely a single point mutation which may be different in each family. Because of the severity of the bleeding diathesis, prophylaxis is desirable and has been shown to be very effective as the in vivo half-life of plasma XIII is long, and low plasma levels are sufficient for haemostasis. Acquired inhibitors have been reported in only two cases with inherited XIII deficiency. Acquired XIII deficiency has been described in a variety of diseases and bleeding has been controlled by therapy with large doses of XIII in such conditions as Henoch-Schönlein purpura, various forms of colitis, erosive gastritis and some forms of leukaemia. Large dose XIII therapy has also been used in an endeavour to promote wound healing after surgery and bone union in non-healing fractures. The use of XIII in these conditions remains controversial. Very rarely a bleeding diathesis results from the development of a specific inhibitor to XIII arising de novo, often as a complication in the course of a disease or in association with long-term drug therapy. The bleeding diathesis in these patients is difficult to treat.

Coagulation factor XIII (FXIII) is of paramount importance in the process of fibrin stabilization, which is the final step of the coagulation cascade. The clinical significance of defective fibrin stabilization is highlighted by the severe hemorrhagic manifestations of congenital FXIII deficiency. In this paper we review the pathophysiology, clinical presentation and therapy of acquired plasma FXIII deficiencies, caused by specific inhibitors or associated with other clinical conditions. For acquired severe FXIII deficiency caused by factor-specific inhibitors, the need for prompt diagnosis and treatment is emphasized by the high hemorrhagic risk and mortality. For moderate reduction of FXIII secondary to other conditions, we discuss the relative importance of FXIII reduction in the development of clinical symptoms and the role of substitution treatment.

An assay for rapid factor XIII activity measurement has been developed based on the determination of the ammonium released during fibrin stabilization. Factor XIII was activated by thrombin and calcium. Ammonium was measured by an ammonium-sensitive electrode. It was demonstrated that the assay procedure yields accurate and precise results and that factor XIII-catalyzed fibrin stabilization can be measured kinetically. The amount of ammonium released during the first 90 min of fibrin stabilization was found to be 7.8 +/- 0.5 moles per mole fibrinogen, which is in agreement with the findings of other authors. In 15 normal subjects and in 15 patients suffering from diseases with suspected factor XIII deficiency there was a satisfactory correlation between the results obtained by the "ammonium-release-method', Bohn's method, and the immunological assay (r1 = 0.65; r2 = 0.70; p less than 0.01). In 3 of 5 patients with paraproteinemias the values of factor XIII activity determined by the ammonium-release-method were markedly lower than those estimated by the other methods. It could be shown that inhibitor mechanisms were responsible for these discrepancies.

The influence of the fibrin-stabilizing coagulation factor XIII is necessary for the formation of a stable blood clot. The factor is not included in the usual global coagulation tests. The presence of lowered concentrations of this factor can be congenital or acquired as a result of various diseases. A lowered concentration of factor XIII was demonstrated in six patients with otherwise normal coagulation tests during a secondary hemorrhage a few days after an extraction. The hemorrhage was attributed to the lowered resistance of the instable blood clot over against the fibrinolytic characteristics of the buccal cavity milieu.