Contact activation factors in plasma from pregnant women--increased level of an association between factor XII and kallikrein

Comparison of factor XII levels in gestational diabetes, fetal macrosomia, and healthy pregnancies

Background

If not detected and treated, gestational diabetes mellitus (GDM) can cause serious pregnancy complications such as macrosomia, preeclampsia, and fetal/neonatal mortality. Many studies have examined underlying contributing factors for GDM, including hypercoagulation. Factor XII (FXII) is a coagulation factor that increases throughout normal pregnancies, and we evaluated the relationship of GDM with FXII, FXIIa (activated FXII), and other coagulation parameter levels. GDM and macrosomia are closely related, but it is not known whether FXII could be an independent causal factor for macrosomia.

Methods

In this prospective study, blood samples were taken from 69 pregnant women at the time of term delivery to determine levels of FXII, FXIIa, and other coagulation parameters. Based on the results, pregnancies fell into GDM, non-diabetic with macrosomia (M), or healthy (C [control]).

Results

FXII concentration levels were significantly higher in GDM patients compared with the M and C groups. There were no significant differences when comparing FXIIa, activated partial thromboplastin time, prothrombin time (PT), and international normalized ratio. The GDM group saw a significant negative correlation between FXII concentrations and maternal pregestational body mass index (BMI) and BMI before delivery. In the M group, a positive correlation was observed between FXII concentrations and newborn weight and newborn weight percentile.

Conclusions

An increase in FXII levels was observed in patients with gestational diabetes. Associations between coagulation parameters and GDM should be further analyzed to define the mechanisms of GDM and possible treatment modalities.

Trial registration

Our study has been registered at clinicaltrials.gov (NCT03583216). Registered on July 11, 2018,

Transforming growth factor-β1 induces expression of human coagulation factor XII via Smad3 and JNK signaling pathways in human lung fibroblasts

Coagulation factor XII (FXII) is a liver-derived serine protease involved in fibrinolysis, coagulation, and inflammation. The regulation of FXII expression is largely unknown. Transforming growth factor-beta1 (TGF-beta1) is a multifunctional cytokine that has been linked to several pathological processes, including tissue fibrosis by modulating procoagulant and fibrinolytic activities. This study investigated whether TGF-beta1 may regulate FXII expression in human lung fibroblasts. Treatment of human lung fibroblasts with TGF-beta1 resulted in a time-dependent increase in FXII production, activation of p44/42, p38, JNK, and Akt, and phosphorylation and translocation into the nucleus of Smad3. However, TGF-beta1-induced FXII expression was repressed only by the JNK inhibitor and JNK and Smad3 antisense oligonucleotides but not by MEK, p38, or phosphoinositide 3-kinase blockers. JNK inhibition had no effect on TGF-beta1-induced Smad3 phosphorylation, association with Smad4, and its translocation into the nucleus but strongly suppressed Smad3-DNA complex formation. FXII promoter analysis revealed that the -299/+1 region was sufficient for TGF-beta1 to induce FXII expression. Sequence analysis of this region detected a potential Smad-binding element at position -272/-269 (SBE-(-272/-269)). Chromatin immunoprecipitation and streptavidin pulldown assays demonstrated TGF-beta1-dependent Smad3 binding to SBE-(-272/-269). Mutation or deletion of SBE-(-272/-269) substantially reduced TGF-beta1-mediated activation of the FXII promoter. Clinical relevance was demonstrated by elevated FXII levels and its co-localization with fibroblasts in the lungs of patients with acute respiratory distress syndrome. Our results show that JNK/Smad3 pathway plays a critical role in TGF-beta1-induced FXII expression in human lung fibroblasts and implicate its possible involvement in pathological conditions characterized by elevated TGF-beta1 levels.

Grafting of PEO to glass, nitinol, and pyrolytic carbon surfaces by gamma irradiation

Glass, nitinol, and pyrolytic carbon surfaces were grafted with poly (ethylene oxide) (PEO) and PEO-containing Pluronic surfactants by gamma irradiation. These substrates were coated with a primer layer of trichlorovinylsilane (TCVS), which allows grafting of organic polymers. The TCVS-coated substrates were adsorbed with PEO or Pluronics and exposed to 0.3 Mrad of gamma radiation to graft the polymer to the surface. PEO-grafted substrates were characterized by contact angle measurement, X-ray photoelectron spectroscopy, fibrinogen adsorption, and platelet adhesion and activation. Surface modification with PEO reduced fibrinogen adsorption by as much as 99%. Platelet adhesion was significnatly reduced or prevented on the modified surfaces. Protein- and platelet-resistance effects were independent of hydrophilicity of the PEO-grafted surfaces. Polymer grafting by gamma radiation to TCVS-coated substrates provides a facile process to improve thromboresistance of inorganic biomaterials.

Contact activation factors in plasma from women on estrogen replacement therapy after ovariohysterectomy

The plasma levels of factor XII, prekallikrein, factor XI, and high molecular weight kininogen were studied in women with bilateral oophorectomy and hysterectomy who received hormone replacement therapy with a 2 mg daily dose of estradiol valerate. Also plasminogen activator activity was investigated. The observations made provide support for the assumption that the low doses of estrogen used in hormone replacement therapy do not significantly affect the levels of contact activation or fibrinolytic factors in plasma. Plasma obtained from young, healthy women was used as a standard reference material. Significantly higher levels of factor XII and prekallikrein were registered in functional tests in the ectomized women than in the reference material, an increase not observed in the immunological assays. These observations are discussed in light of recently published data from our laboratory on an increase in the measured level of factor XII obtained upon the removal of IgG before assay. Also a marked increase in urokinase activity was registered in the ectomized women. The high levels of factor XII, prekallikrein, and urokinase, as compared with the reference material, seemed to be age dependent, being also observed in a group of naturally postmenopausal women.

Amidolytic assay of factor XI in human plasma--significance of kallikrein for the activity measured

Factor XI (FXI) deficiency is associated with an abnormal bleeding state. The extent of bleeding does not correlate well with the plasma concentration of FXI, and it has been suggested that also unknown factors interfere with the bleeding tendency. In a recent paper (Thromb. Res. 74, 477-485, 1994) we found that FXIa activated in human plasma was present in association with part of factor XIIa (FXIIa) and part of kallikrein, influencing their functional activities. Should the activity level of FXIa also be altered by the other contact factors this might provide one approach to the problem of the failure of assays of FXIa to correlate with bleeding tendency. In the present study we have developed an assay procedure for FXIa based on its amidolytic (S-2366) activity, and allowing at the same time a quantification of the amount of FXIa associated to kallikrein. The total amidase activity obtained was separated into two main fractions by use of soybean trypsin inhibitor (STI), corn inhibitor (CI) and lima bean trypsin inhibitor (LTI). One fraction contained free FXIa which could be specifically blocked by LTI. An inhibitor resistant fraction was found to contain FXIa inactive in association with kallikrein. The content of FXIa could be assessed in experiments with mixtures of normal plasma and plasma deficient in prekallikrein, and was taken into account in the calculations. This fraction increased during storage of plasma at -70 degrees C. To obtain stable and comparable assay conditions the method was based on plasma stored for at least four weeks. The specificity of the method was verified by parallel radial immunodiffusion tests. The results imply that the activity level of FXIa is dependent on kallikrein present. If the experimental results has relevance to the situation under physiological conditions, they indicate one possible cause of the failure of assays of FXI to correlate with bleeding tendency.