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PubMed1985

Cold promoted activation and factor XII, prekallikrein and C1-inhibitor.

During incubation of plasma in the cold an amidolytic activity due to the kallikrein-alpha 2-macroglobulin complex appears in the plasma of about 40% of the women under hormonal contraception. The factor XII and prekallikrein activity are significantly increased 151.9% and 112.4% respectively in the cold promoted activation positive plasmas (CPA pos) whereas the activity of C1-inhibitor is decreased, 76%. The quotient of the product of the C1-inhibitor and alpha 2-macroglobulin values divided by the product of the FXII and prekallikrein values is significantly lower in the CPA pos plasma 0.49 than in CPA neg plasma 0.96 (p less than 0.05). These results alone do not explain the cold promoted activation, since a patient with a C1-inhibitor as low as 9% showed no increase of the amidolytic activity after a 24 hr incubation at 4 degrees C. However, the addition of purified C1-inhibitor to a CPA pos. plasma inhibits the cold activation. Heparin at a concentration of 0.5 IU/ml delays the appearance of the amidolytic activity.

Adolescent↗
PubMed1991

Localization of distinct functional domains on prekallikrein for interaction with both high molecular weight kininogen and activated factor XII in a 28-kDa fragment (amino acids 141-371).

The predominant autolytic form of human kallikrein, beta-kallikrein, was used to localize the high molecular weight kininogen (HK) binding site on kallikrein as well as the substrate recognition site for activated factor XII on prekallikrein. beta-Kallikrein is formed by autolysis of the kallikrein heavy chain to give two fragments of approximately 18 and 28 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A ligand binding technique established that the HK binding site on kallikrein residues on the 28-kDa fragment of the heavy chain. Limited NH2-terminal sequencing of this portion of beta-kallikrein showed that this fragment of the heavy chain consists of the COOH-terminal 231 amino acids of the heavy chain. A panel of five murine monoclonal antibodies to human prekallikrein (PK) were found to have epitopes on this same fragment of the heavy chain. None of the monoclonal antibodies were able to block binding of HK to PK. Three of the monoclonal antibodies (13G11, 13H11, and 6A6) were able to inhibit the activation of PK to kallikrein in both a plasma system and a purified system. The 28-kDa fragment of the PK heavy chain was purified and was able to compete with HK for binding to PK. The HK binding site and the site of recognition of factor XII are separate and distinct on PK, and both are contained in the COOH-terminal 231 amino acids of the PK heavy chain.

Animals↗
PubMed2003

Glycosaminoglycans affect the interaction of human plasma kallikrein with plasminogen, factor XII and inhibitors.

Human plasma kallikrein, a serine proteinase, plays a key role in intrinsic blood clotting, in the kallikrein-kinin system, and in fibrinolysis. The proteolytic enzymes involved in these processes are usually controlled by specific inhibitors and may be influenced by several factors including glycosaminoglycans, as recently demonstrated by our group. The aim of the present study was to investigate the effect of glycosaminoglycans (30 to 250 micro/ml) on kallikrein activity on plasminogen and factor XII and on the inhibition of kallikrein by the plasma proteins C1-inhibitor and antithrombin. Almost all available glycosaminoglycans (heparin, heparan sulfate, bovine and tuna dermatan sulfate, chondroitin 4- and 6-sulfates) reduced (1.2 to 3.0 times) the catalytic efficiency of kallikrein (in a nanomolar range) on the hydrolysis of plasminogen (0.3 to 1.8 microM) and increased (1.9 to 7.7 times) the enzyme efficiency in factor XII (0.1 to 10 microM) activation. On the other hand, heparin, heparan sulfate, and bovine and tuna dermatan sulfate improved (1.2 to 3.4 times) kallikrein inhibition by antithrombin (1.4 microM), while chondroitin 4- and 6-sulfates reduced it (1.3 times). Heparin and heparan sulfate increased (1.4 times) the enzyme inhibition by the C1-inhibitor (150 nM).

Animals↗
PubMed1989

Assay of factor XII in human plasma using prekallikrein or the chromogenic peptide S-2222 as substrates--significance of the functional state of plasma kallikrein.

Factor XII was assayed in acetone-treated and kaolin-activated human citrated plasma (total plasma dilution 1.0 + 0.3 v/v during activation with kaolin, 1.8 mg/ml incubate). Measurements were performed with the tetrapeptide Bz-Ile-Glu-Gly-Arg-pNa (S-2222) and with prekallikrein as substrates. The correlation of both methods to another S-2222 based method recently described was good, r = 0.90 and 0.85 for the two methods respectively. Under the assay conditions used, FXIIa was present as a S-2222 amidase that could be blocked by corn inhibitor, whereas plasma kallikrein was found to be present partly as an amidase blocked by a low concentration of soybean trypsin inhibitor, and partly in a functional state not inhibited and adding to the measured level of FXII. The presence of benzamidine 0.7 to 2.1 mM during acetone treatment increased the measured level of FXII assayed both as prekallikrein activator and as S-2222 amidase.

Buffers↗
PubMed1980

Induction of acute cholecystitis by activation of factor XII.

Acute, acalculous cholecystitis is seen among patients suffering with bacterial sepsis, burns, trauma, or cancer; clinical conditions that could lead to activation of factor XII-dependent pathways and result in inflammation of the gall bladder. To test this hypothesis, dogs were injected intravenously with ellagic acid or rutin, known polyphenol activators of factor XII, or with Escherichia coli endotoxin, also known to activate factor XII, and monkeys were injected intravenously with ellagic acid. In both species, in vivo activation of factor XII-dependent pathways with polyphenol activator resulted in rapid and selective development of acute vasculitis in the serosa and muscularis of the gallbladder and margination of polymorphonuclear neutrophils in pulmonary blood vessels. Intravenous injection of E. coli endotoxin in dogs resulted in necrosis and thrombosis of vessels that were especially severe in the serosa and muscularis of the gallbladder but also present in vessels of many other organs. These observations indicate that blood vessels of the gall bladder and, to a lesser degree, the lung are especially sensitive to injury consequent to in vivo activation of factor XII-dependent pathways and, in view of the common ingestion of plant polyphenols, may provide important insight into the pathogenesis of cholecystitis in man.

Animals↗
PubMed2003

[Anesthetic management of a patient with deficiency of congenital coagulation factor XII].

A 63-year-old man with deficiency of congenital coagulation factor XII, was referred to our hospital for an operation of the hypopharynx cancer. The day before surgery under general anesthesia, fresh frozen plasma was administered to him with good response of APTT shortening from 397.0 to 36.4 seconds. During operation, bleeding tendency was controlled and fresh frozen plasma was administered. Total blood loss during the operation was 255 ml. During post-operative period, APTT was kept at an adequate level. The post-operative course was uneventful and he was discharged after the radiation and an adjuvant therapy.

Anesthesia, General↗
PubMed1984

[Coagulation factor XII deficiency, a contribution to thrombophilia].

The hereditary deficiency of Hageman's factor rarely occurs. The patients are mostly detected by chance. The leading symptom is the considerably prolonged partial thromboplastin time. A haemorrhagic diathesis is not present. Since in these patients thromboemoblic diseases are possible, in an ascertained diagnosis the prevention of thrombosis should be performed.

Diagnosis, Differential↗
PubMed1993

Effect of surface-immobilized heparin on the activation of adsorbed factor XII.

Two different heparin surfaces, structurally closely related and of similar negative charge characteristics, were compared with regard to adsorption and activation of coagulation Factor XII (FXII). One surface was prepared by immobilization of unfractioned heparin, which yielded a surface containing both heparin molecules with high and with low affinity for antithrombin (unfractioned [UF] heparin surface). The other surface consisted of a fraction of heparin molecules with low affinity for antithrombin (LA heparin surface) and essentially devoid of antithrombin-binding as well as anticoagulant activity. Both surfaces adsorbed FXII from plasma to a similar extent, and essentially the same quantities of bound factor could be recovered from the surfaces. The two heparin surfaces, however, differed markedly with regard to activation of the adsorbed FXII. On the LA heparin surface, a major portion of the surface-bound FXII was recovered in its enzymatically active form (FXIIa), but only trace amounts of the FXII taken up by the UF heparin surface had undergone activation. When FXII-deficient plasma was used instead of normal plasma, no surface-associated enzyme activity could be recovered on either surface. The presence of free standard heparin or low molecular weight heparin in the plasma exposed to the LA heparin surface did not prevent conversion of FXII to FXIIa.

Adsorption↗
PubMed2007

Ordered adsorption of coagulation factor XII on negatively charged polymer surfaces probed by sum frequency generation vibrational spectroscopy.

Electrostatic interactions between negatively charged polymer surfaces and factor XII (FXII), a blood coagulation factor, were investigated by sum frequency generation (SFG) vibrational spectroscopy, supplemented by several analytical techniques including attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), quartz crystal microbalance (QCM), zeta-potential measurement, and chromogenic assay. A series of sulfonated polystyrenes (sPS) with different sulfonation levels were synthesized as model surfaces with different surface charge densities. SFG spectra collected from FXII adsorbed onto PS and sPS surfaces with different surface charge densities showed remarkable differences in spectral features and especially in spectral intensity. Chromogenic assay experiments showed that highly charged sPS surfaces induced FXII autoactivation. ATR-FTIR and QCM results indicated that adsorption amounts on the PS and sPS surfaces were similar even though the surface charge densities were different. No significant conformational change was observed from FXII adsorbed onto surfaces studied. Using theoretical calculations, the possible contribution from the third-order nonlinear optical effect induced by the surface electric field was evaluated, and it was found to be unable to yield the SFG signal enhancement observed. Therefore it was concluded that the adsorbed FXII orientation and ordering were the main reasons for the remarkable SFG amide I signal increase on sPS surfaces. These investigations indicate that negatively charged surfaces facilitate or induce FXII autoactivation on the molecular level by imposing specific orientation and ordering on the adsorbed protein molecules.

Adsorption↗
PubMed1989

A new assay for the determination of factor XII in plasma using a chromogenic substrate and a selective inhibitor of plasma kallikrein.

A new chromogenic assay for factor XII in plasma was designed by the use of the soluble activator Kalliplastin, the substrate H-D-HHT-Gly-Arg-pNA and a synthetic inhibitor of plasma kallikrein (Pefabloc PK). The assay was carried out in one and the same cuvette and did not require factor XII-deficient plasma. There was a good correlation between F XII coagulant and amidolytic assays.

Benzamidines↗
PubMed1983

Synthesis and release of Hageman factor (Factor XII) by the isolated perfused rat liver.

The site of synthesis of Hageman factor (HF, Factor XII) has not been previously demonstrated with certainty. We have studied the production and release of HF in the isolated perfused rat liver and have compared rates of synthesis in this system with absolute rates of degradation measured in vivo. Rat livers, perfused for 5 h with a recycling fluid consisting of a perfluorochemical emulsion (Fluosol 43), were used to demonstrate a cumulative increase of HF in the perfusate as measured by a specific and sensitive radioimmunoassay. The rate of increase in the perfusate pool of HF during the final 4 h of perfusion yielded a mean synthetic rate of 3.5 micrograms/h per 100 g body wt, which was approximately 0.2% of the synthetic rate of albumin in the same system. The cumulative appearance of albumin and transferrin was linear after 1 h and calculated rates of synthesis were 2,012 micrograms/h per 100 g and 263 micrograms/h per 100 g body wt, respectively. De novo synthesis of HF was confirmed by demonstrating incorporation of [14C]lysine into specific immunoprecipitates of HF, and by the observations that both specific incorporation of labeled amino acid and net release of immunoassayable HF were inhibited by the administration of cycloheximide. Finally, it was evident that the rates of synthesis observed in the isolated perfused liver agreed closely with absolute rates of degradation of HF measured in vivo with 125I-rat HF (4.0 micrograms/h per 100 g). From these data we conclude that the liver is the principal site of synthesis of HF.

Animals↗
PubMed2006

Endothelial cells express a matrix protein which binds activated factor XII in a zinc-independent manner.

Recent studies have shown that peptides identified as surface binding regions of high molecular mass kininogen (HK) and factor XII (FXII) inhibit the Zn(2+)-dependent binding of FXII to confluent layers of human umbilical vein endothelial cells (HUVEC). This indicates that negatively charged FXII binding surfaces, such as sulfatides and dextran sulfate, may interfere with the binding of FXII to confluent layer of HUVEC. Upon investigating this hypothesis it was unexpectedly found that sulfatides enhanced a specific binding of FXII to a matrix protein expressed during growth of the endothelial cells and that this binding was independent of the presence of Zn(2+). The function of sulfatides was partly to minimize nonspecific electrostatic binding and partly to induce and enhance autoactivation of FXII generating alphaFXIIa. Western blot analysis of the extracts of the matrix incubated with FXII and sulfatides showed that the binding was specific for alphaFXIIa. The dissociation constant for binding alphaFXIIa was 12.8 +/- 0.4 nM (n = 4). The binding of alphaFXIIa to ECM was mapped to the heavy chain as no binding was observed of the light chain containing the catalytic domain. HK, which previously has been shown to completely abolish the Zn(2+)-dependent binding of FXII to confluent layers of HUVEC, did not inhibit the binding of alphaFXIIa to the matrix but sulfatides enhanced binding of FXII to ECM. This suggests that HK interferes with the binding of FXII to sulfatides and thereby the autoactivation of FXII. Trypsin treatment of the matrix protein completely abolished the binding, and fibronectin but not laminin was found to be a suitable target. The binding of activated FXII to the ECM suggests that FXIIa may be a modulator of cellular adhesion, migration and vascularization.

Endothelial Cells↗
PubMed1992

Factor XII clotting activity and antigen levels in patients with thromboembolic disease.

Individuals with severe factor XII (FXII) deficiency may be prone to thromboembolic disease and this thrombophilic state may be due to insufficient contact activation dependent fibrinolysis. According to our previous study (Thromb Haemostas 1991; 65: 117-121), however, heterozygous FXII deficiency is not a strong prethrombotic risk factor, only one out of 45 obligatory or possible heterozygotes having sustained a thrombotic event. In the present study, FXII clotting activity (FXII:C) and antigen concentration (FXII:AG) were measured in 200 patients having suffered from idiopathic thromboembolism and compared with the values in 200 healthy controls. Mean FXII levels were not significantly different in thrombophilic patients and controls, and subnormal FXII values were not more frequently encountered in patients than in controls. Specific FXII activity, i.e. the ratio of FXII:C to FXII:AG, showed considerable variation in each of the two groups, but patients and controls had a similar distribution of specific FXII activity. Variations in specific FXII activity were not explained by differences in beta 2-glycoprotein I levels. In conclusion, heterozygous FXII deficiency is not a strong prethrombotic risk factor and subnormal FXII values are not more common in thrombophilic patients than in healthy individuals.

Adolescent↗
PubMed1998

Thrombus formation on transcatheter ASD occluder device in a patient with coagulation factor XII deficiency.

Transcatheter occlusion of cardiac defects has become an effective and less invasive alternative to open heart surgery. Thromboembolic complications are rare events, after both surgical and transcatheter closure of atrial septal defects [Galal et al.: Eur Heart J 15:1381-1384, 1994]. We report on a case of thrombus formation on the atrial septal defect occluder system (ASDOS) [Sievert et al.: Cathet Cardiovasc Diagn 36:232-240, 1995; Hausdorf et al.: Heart 75:83-88, 1996]. Two days after transcatheter occlusion, the patient suffered an acute stroke due to embolism despite anticoagulation with intravenous heparin. A coagulation disorder with reduced factor XII concentration was deduced as the likely cause. Repeated transesophageal echocardiographic (TEE) studies revealed an involution of the intracardial thrombus within weeks of subsequent anticoagulatory treatment. First off, this case shows that patients with factor XII deficiency are at risk for thromboembolism. Second, it again clarifies that even large amounts of intraartrial thrombotic material may not be seen by transthoracic echocardiography (TTE) and underscores the necessity of performing TEE. Screening patients for coagulation disorders (Quick's value (Q), partial thromboplastin time (PTT)) before they are selected for treatment with thrombogenic devices is indispensable. With regard to their personal history (earlier thromboembolism) and the result of this screening (e.g., prolongation of PTT), quantitative determination of coagulation factors is reasonable. If patients endangered by thromboembolic complications nevertheless undergo ASD occlusion procedures, anticoagulation monitoring requires exceptional attention. Furthermore, it is recommended that TEE should be carried out in these patients 2 days after treatment, since transthoracic echocardiography (TTE) might be unable to detect thrombus formation on the device.

Cardiac Catheterization↗
PubMed1980

Activation of factor XII in plasma from rats pretreated with tranexamic acid. Inhibition of a plasmin-induced loss of the functional activity of high molecular weight kininogen.

Incubation of plasma from rats pretreated with tranexamic acid (40 mg/100 g) with acetone (23% V/V) yielded enzyme preparations in which all the plasminogen present was recovered as plasmin and a plasmin-like substance without affinity for lysine-Sepharose. This substance, designated "plasmin", was separated from plasmin and kallikrein in a three-step procedure using columns of lysine-Sepharose, DEAE-Sephadex A-50, and arginine-Sepharose. The ratios of fibrinolytic, caseinolytic, LEe esterase, BAEe esterase and kininogenase activities of "plasmin" corresponded well with those of rat plasmin and human plasmin. Both rat plasmin and "plasmin" destroyed the capacity of high molecular weight kininogen (HMWK) to function as a cofactor in the activation of factor XII in rat plasma, without causing a corresponding release of the kinin part of the molecule. Rat plasma kallikrein induced full release of kinin from HMWK, but the functional capacity was retained. It is suggested that the reduced extent of activation of factor XII observed in plasma from rats injected intravenously with dextran, or rat plasma that has been passed through a column with lysine-Sepharose, is due to the loss of functional HMWK caused by plasmin activated in vivo or on the column.

Animals↗
PubMed2006

Specific types of activated Factor XII increase following thrombolytic therapy with tenecteplase.

BACKGROUND: Activated Factor XII (XIIa) is believed to participate in a number of pathophysiological processes including inflammation, thrombosis and fibrinolysis. Increasing XIIa levels following thrombolytic therapy have previously been reported. In contrast to other thrombolytics, tenecteplase (TNK-tpa) does not show paradoxical thrombin activation, indicating a lower procoagulant effect of this fibrin-selective thrombolytic agent. Recent research has demonstrated that in-vivo XIIa exists in a number of different types, and the aim of this study was to investigate plasma variations of different types of XIIa following thrombolytic treatment with TNK-tpa. METHODS: Citrated blood samples were obtained from 34 patients admitted with acute ST-elevation myocardial infarction (STEMI) treated with TNK-tpa. Samples were taken immediately prior to treatment, 30-90 min after and 4 days post-treatment. XIIa measurements were performed using 2 ELISA assays designed to preferentially measure different types of XIIa; XIIaA and XIIaR. Both assays utilised a monoclonal antibody 2/215, which is highly specific for XIIa, as the solid phase capture antibody. The assay for XIIaA used a conjugate based on a polyclonal antibody against the entire XIIa molecule, whilst the assay for XIIaR incorporated a reagent to release otherwise unavailable XIIa and used a conjugate based on a monoclonal antibody against beta-XIIa. RESULTS: Changes in plasma XIIaA concentration as a result of therapy were more evident than changes in XIIaR concentration. XIIaA showed a significant increase from 67.1 (49.0-84.4) pM to 97.8 (75.5-133.1) pM [median and 25 and 75% percentiles] in the 30-90 min sample (P < 0.001), returning to pre-intervention levels 61.5 (47.5-81.0) pM by day 4. In contrast, no significant change in XIIaR concentration was observed following thrombolytic therapy with TNK-tpa. CONCLUSION: In patients admitted with STEMI, thrombolytic therapy with TNK-tpa resulted in a significant short-lasting increase in specific types of XIIa (namely XIIaA), whereas other types of XIIa (XIIaR) were largely unaffected by this intervention.

Aged↗
PubMed1989

A new writhing model of factor XII activator-induced pain for assessment of non-steroidal anti-inflammatory agents. I. Kaolin-induced writhing in mice.

The writhing reaction in mice induced by kaolin, a factor XII activator, was studied. An intraperitoneal injection of kaolin clearly induced a writhing reaction in a dose-dependent fashion, and the reaction disappeared about 10-15 min later. The writhing reaction reached a peak at 5-10 min after the injection of kaolin (0.5 ml/mouse, i.p.; 5 mg/ml saline). A simultaneous intraperitoneal injection of soybean trypsin inhibitor (SBTI, 2.5 mg/mouse) almost completely suppressed the writhing reaction caused by kaolin (2.5 mg/mouse) for the first 10 min. The kaolin-induced writhing reaction was markedly potentiated by a simultaneous intraperitoneal injection of captopril (50 micrograms/mouse). At 60 min after kaolin injection during the disappearance of the writhing reaction, the reaction reappeared when captopril was injected, but reactions observed at this later stage were completely blocked by SBTI. Indomethacin, ibuprofen and alminoprofen inhibited the writhing reaction dose-dependently. Kaolin thus induces a clear and reproducible writing reaction, which might be mainly dependent on the action of bradykinin via activation of factor XII, and should prove to be a simple and convenient model of bradykinin-induced pain for the assessment of analgesic actions.

Acetylcholine↗