Factor XIII in a Clinical Material

In 339 patients with various diseases factor XIII (FSF) was determined with the specific amine incorporation method of Lorand et al (1969). Normal values were found in patients with renal (216 patients) or liver diseases (33 patients), in 39 patients with recurrent deep venous thrombosis and in 17 children with congenital cyanotic heart disease. Low levels were found in patients with various conditions, such as sepsis, multiple fractures and combustio complicated by an abnormal proteolytic activity (fibrinolysis and/or activation of the coagulation system with signs of disseminated coagulation). No correlation was found between the FSF and the fibrinogen values or the levels of fibrin/fibrinogen degradation products (FDP). Low FSF values were found in 4 patients with erosive gastritis, with gastrointestinal bleedings and a local fibrinolytic activity in the gastric juice. Although the FSF must be very low (<1%) if it is to cause bleedings, the low levels in these patients with many other coexisting disturbances in the coagulation system and/or an increased fibrinolytic activity most probably contribute to the increased bleeding tendency in such patients.     

Factor XIII: Inherited and acquired 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 (γ-glutamyl)lysine link. It also crosslinks other proteins, including fibronectin and alpha-2-plasmin inhibitor (α-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 haemostatis. 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 bleding 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.     

Factor XIII deficiency

Summary. 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 and venous thromboembolism

Plasma factor XIII (FXIII) is a tetrameric zymogen consisting of two potentially active A subunits (FXIII-A) and two carrier/inhibitory B subunits (FXIII-B). In the final phase of the coagulation cascade, FXIII is converted into an active transglutaminase (FXIIIa) by thrombin and Ca (2 + ). FXIIIa strengthens fibrin clot mechanically by cross-linking fibrin chains. In addition, FXIIIa is a key regulator of fibrinolysis, protecting newly formed fibrin from the fibrinolytic machinery by binding α (2)-plasmin inhibitor to the fibrin meshwork. FXIII is essential for maintaining hemostasis; its severe deficiency causes a life-threatening bleeding diathesis. The involvement of FXIII in thrombotic diseases and its association with the risk of these disorders is less clear. The role of FXIII in atherothrombotic diseases has been recently reviewed. This article offers a general overview of the relationship between FXIII and venous thromboembolism (VTE), to collect individual publications on this topic, present conclusions, and examine limitations of published studies. Special attention is given to the association of FXIII-A polymorphism with the risk of VTE, which has provoked considerable interest over the last decade.     

Clot Retraction in a Factor XIII Free System

The role of Factor XIII in clot retraction was studied using the plasma from Factor XIII-deficient patients. Time course experiments revealed no significant difference in clot retraction between a plasma deficient in Factor XIII and one to which purified Factor XIII had been added. Using Factor XIII-free fibrinogen and Factor XIII-deficient platelets, it is shown that there is no significant difference in clot retraction with or without added Factor XIII.     

Immunochemical Characterization of a Human Antibody to Factor XIII

Dispersed and intact marrow fragmentshave been implanted in the omentum andsubcutaneous fat of irradiated and nonirradiated hosts. Osteogenesis and hemopoiesis in varying proportions wereobserved at 10 and 35 days. The subcutaneous site favored osteogenesis, theomental site and host irradiation prior totransplant resulted in predominance ofhemopoiesis. In dispersed and recompacted marrow grafts, only hemopoiesisdeveloped. Differentiation was predominantly granulocytic. Osteogenesis is notan obligatory prerequisite of hemopoiesisin extramedullary sites.

Submitted on January 31, 1973 Revised on April 23, 1973 Accepted on April 25, 1973     

Serum antibodies to collagen XIII: a further good marker of active Graves' ophthalmopathy

OBJECTIVE: In Graves' ophthalmopathy (GO) intercellular adhesion molecule-1 (ICAM-1) is thought to play a key role in lymphocyte infiltration into the orbit, and serum levels of its soluble form are positively correlated to clinical activity score (CAS). Serum antibodies against collagen XIII (CollXIIIAb), a plasma membrane protein expressed at a low level in almost all connective tissue-producing cells, have been detected in GO, but their significance is unclear. The aim of this study was to search for CollXIIIAb in Graves' patients with and without ophthalmopathy and to correlate their levels with CAS and with serum soluble ICAM-1 (sICAM-1) values. PATIENTS: We studied 66 patients with Graves' disease whose sera had been previously tested for sICAM-1 levels, grouped as follows: 28 with moderate and active ophthalmopathy (group 1), 12 of them hyperthyroid (group 1a) and 16 euthyroid (group 1b); 13 with mild and inactive ophthalmopathy and normal thyroid function (group 2); 25 without ophthalmopathy (group 3), 11 of them hyperthyroid (group 3a) and 14 euthyroid (group 3b). Finally, 26 sera of normal controls were studied. MEASUREMENTs: CollXIIIAb were evaluated by an enzyme-linked immunosorbent assay (ELISA) method. RESULTS: In group 1 patients, CollXIIIAb were detected at high levels in 8/12 (66.6%) in group 1a [optical density (OD) ranging from 0.529 to 0.894] and in 10/16 (62.5%) in group 1b (OD 0.560-0.855). In group 2 patients, CollXIIIAb were detected but at low levels (OD 0.205-0.260) in 4/13 patients (30.7%). In group 3 patients, CollXIIIAb were present at low levels in 6/11 (54.5%) of group 3a and in 5/14 (35.7%) of group 3b (OD 0.215-0.290 and 0.144-0.245, respectively). CollXIIIAb were detected in only 4/26 normal controls (15%) but at low levels (OD 0.150-0.185). CollXIIIAb values in both groups 1a and 1b were significantly higher than those of the remaining groups. A positive correlation between CollXIIIAb levels and CAS but not thyroid hormone levels was found in groups 1a, 1b and 2. Moreover, a positive correlation between CollXIIIAb levels and sICAM-1-values was also evidenced in all three groups. CONCLUSIONS: Our results suggest that CollXIIIAb could be considered as a further good marker of active inflammatory processes involving the adipose connective tissue in GO. In particular, the high levels of CollXIIIAb in sera of Graves' patients with active ophthalmopathy could reflect an increased expression of type XIII collagen on the membrane of activated fibroblasts in these patients. Thus, the evaluation of these antibodies could be added to other known markers as a useful and inexpensive tool in monitoring Graves' patients and in modulating the treatment of GO.     

Characteristics of the Factor VIII Protein and Factor XIII in Various Factor VIII Concentrates

The in vitro properties of 5 factor VIII preparations (AHF-Kabi, Hemofil Hyland, AHF-Profilate Abbott, Kryobulin Immuno and Factorate High Purity Armour) and an ordinary cryoprecipitate were studied with reference to factor VIII clotting activity (VIII:C), factor VIII clotting antigen (VIILCAg), factor VIII related antigen (VIIIR:Ag) (EI, IRMA, CIE), ristocetin cofactor activity (VIIIR:RCF), fibrinogen and factor XIII. All the preparations with the exception of Factorate had higher levels of VIII:CAg than VIII:C indicating inactivation of the biological activity of VIII:C during the procedure. AHF-Kabi (fraction I-0) and the cryoprecipitate, the only preparations capable of normalising the defect in patients with von Willebrand's disease, showed the same level of VIIIR:Ag determined by EI and by IRMA, while all the other preparations (i.e. cryoprecipitates purified further in different ways) had considerably lower levels of VIIIR:Ag determined by IRMA than by EL Based on these in vitro techniques it seems to be possible to predict which preparations can be used successfully in patients with von Willebrand's disease, while no such conclusions can be made from VIIIR:RCF determinations. EI yielded similar concentrations of factor XIII a subunit in all the preparations tested. 3 functional assays showed high factor XIII activities in AHF-Kabi but low or no activities in the others. Thus, considerable differences were found of the in vitro properties of the proteins in 5 factor VIII concentrates and a cryoprecipitate. The action of proteases and the techniques used in the purification procedure are probably of crucial importance for the properties of the various factors.     

Factor XIII in primary antiphospholipid syndrome

OBJECTIVE: To evaluate the clinical significance of factor XIII (FXIII) in primary antiphospholipid syndrome (APS). METHODS: A cross-sectional study including patients with primary APS (n =29), persistent carriers of idiopathic antiphospholipid antibodies (aPL) with no history of thrombosis (n = 14), thrombotic patients with inherited thrombophilia (n =24), healthy controls (n =28), and patients with mitral and aortic valve prosthesis (n =32, as controls for FXIII only). FXIII and fibrinogen were measured by functional assays: IgG anticardiolipin antibody (aCL), IgG anti-beta2-glycoprotein I (anti-beta2-GPI), and plasminogen activator inhibitor (PAI) by immunoassay; and paraoxonase activity by paranitrophenol formation. Intima-media thickness (IMT) of carotid arteries was determined by high resolution sonography. RESULTS: FXIII activity (FXIIIa) was highest in primary APS (p= 0.001), particularly in patients with multiple occlusions (n =12) versus those with single occlusion (158 +/- 45% vs 118 +/- 38%; p=0.02). In primary APS, FXIII positively correlated with PAI (p=0.003) and fibrinogen (p = 0.005). Similarly in the thrombotic control group, FXIIIa correlated with PAI (p =0.05) and fibrinogen (0.007). In primary APS, FXIIIa was related to the IMT of all carotid artery segments (p always < 0.01). In thrombotic controls FXIIIa correlated only to the IMT of the common carotid (p =0.01). In primary APS, FXIIIa was strongly associated with IgG aCL and IgG anti-beta2-GPI (p=0.005 for both). These associations were weaker in the aPL group (FXIIIa with IgG aCL, p= 0.02, with IgG anti-beta2-GPI, p=0.04). CONCLUSION: Enhanced FXIII activity may contribute to atherothrombosis in primary APS via increased fibrin/fibrinogen cross-linking. This pathway is not exclusive to primary APS, being present also in thrombotic controls, but the presence of IgG aPL may favor a higher degree of FXIIIa activation in the primary APS group.     

Factor XIII Deficiency in Siblings: Importance of Prophylactic Replacement

Factor XIII deficiency, an autosomal recessive trait, can result in serious bleeding manifestation. This case report presents two brothers with Factor XIII deficiency. Though the younger sibling had been screened and diagnosed prophylactic replacement therapy had not been initiated unlike the elder brother. He presented with intracranial haemorrhage needing surgical evacuation while the elder brother remained symptom free on regular prophylactic replacement of FFP.     

The Half-life of Factor XIII in Vivo

S ummary . Factor-XIII levels were measured in the plasma of two patients with congenital deficiency following infusions of fresh frozen plasma at times remote from an episode of bleeding. The disappearance curve of factor XIII from the plasma showed an initial rapid and then a slow component, the half-life of the slow phase being about 12 days which is considerably greater than most previous estimates. The therapeutic implications of the prolonged effect of infused factor XIII are discussed.     

Factor XIII Assay by an Isotope Method

S ummary . The urea and acetic acid solubility tests to detect deficiency of factor XIII were compared. The urea test is more specific, but the acetic acid test is more sensitive, quicker, and therefore more convenient.
A radioisotope assay method for factor XIII (transamidase) is described. Incorporation of ¹⁴C putrescine into casein provides a substitute for the linkage by transamidation of fibrin monomers. Fresh plasma, fresh frozen plasma and out-dated bank plasma have similar transamidase activity. Slight instability is apparent after storage for 3 days at room temperature. The normal range of plasma factor XIII is wide. Aged serum contained 12.5% of normal plasma transamidase. Platelets are a rich source of transamidase activity, particularly after disruption. Approximately half the total whole blood transamidase resides in the platelets and the remainder in the plasma. Leucocytes and red cells contain no transamidase. After lysis, however, red cells do reveal activity in this assay system. This cross reaction requires further elucidation.
The venom ('Reptilase') of the Brazilian viper, Bothrops jararaca , can activate factor XIII in similar fashion to thrombin.     

PECAM-1: a multifaceted regulator of megakaryocytopoiesis

PECAM-1 (CD31) knockout (KO) mice exhibit excessive megakaryocytopoiesis accompanied by increased numbers of megakaryocytes associated with the stromal niche rather than the vascular niche. During earlier stages of megakaryocytopoiesis in KO marrow, an expanded Lin(-)Sca-1(+) c-kit(+) hematopoietic stem cell (HSC) population and increased quiescent Lin(-) progenitor pool were identified. During the later stages of megakaryocytopoiesis, CD31KO megakaryocytes exhibited abnormal adhesion/transmigration behaviors. Lastly, KO animals exhibited excessive splenic extramedullary megakaryocytopoiesis, which likely compensates for the impaired marrow megakaryocytopoiesis, resulting in normal peripheral platelet number. Thus, PECAM-1 modulates megakaryocytopoiesis in a hierarchic manner, functioning as a thermostat to "fine-tune" megakaryocytopoiesis.     

Deficiency of Factor XIII Gene in Chinese: 3 Novel Mutations

A defect in the factor XIII gene can result in lifelong bleeding tendency. In 3 Chinese families, hereditary coagulation factor XIII deficiency was diagnosed on the basis of the clinical syndrome and solubility of fibrin clot in 5 mol/L urea. We sequenced all of the FXIIIA gene exons and the flanking region and found 3 novel defects in the factor XIII gene. First, C --> G transition at nucleotide (nt) position 1241 in exon 10 results in substitution of Ser413 with Trp. Second, C --> T transition at nt232 in exon 3 results in Arg 77 --> Cys. The third mutation is in exon 5: del-aa at nt598 (codon 191) causes frameshift and premature termination. In the cytoplasm of 3 probands the FXIII gene was normal at the messenger RNA level. Three mutations may affect FXIIIA protein conformation or incorrect protein folding and lead to formation of mutant FXIII that is very unstable and rapidly degraded in cytoplasm.     

Alternative Pathways for the Activation of Factor XIII

Factor XIII is present in plasma as a proenzyme, which when activated catalyses the formation of epsilon(gamma-glutamyl)lysyl bonds in fibrin. In this study the activation of purified plasma factor XIII was examined quantitatively with the fluorescent amine incorporation assay. Activation products were examined by polyacrylamide gel electrophoresis. The serin proteases, thrombin, trypsin, chymotrypsin, and factor Xa, and also Reptilase were tested for their ability to activate factor XIII. Highly purified thrombins activated purified factor XIII; this reaction was not calcium dependent. Trypsin was also a potent activator, but no transglutaminase activity was found with chymotrypsin. The most highly purified preparations of Reptilase had no effect on factor XIII activity. Less purified Reptilase preparations activated factor XIII, which suggests the presence of another enzyme in these Reptilase preparations. Highly purified factor Xa was found to be an effective activator of purified factor XIII. In contrast to thrombin activation, this reaction required calcium. It may be that under certain circumstances factor XIIIa could be formed in vivo directly by the alternative pathway of factor Xa. Factor XIIIa could then crosslink fibrinogen, which would also provide an alternative pathway for thrombus formation. Also, the activation of factor XIII by both factor Xa and thrombin provides a further point of control in the blood coagulation process.