Fibrin-stabilizing Factor XIII Research Articles

The In Vitro Effects of Fibrinogen Concentrate, Factor XIII and Fresh Frozen Plasma on Impaired Clot Formation After 60% Dilution

Previous investigations have shown that increasing fibrinogen concentration improves dilution-dependent impairment of clot formation. We conducted an in vitro study to explore whether substitution with fibrin-stabilizing factor XIII (FXIII) combined with fibrinogen promotes further improvement of clot formation, and whether fibrinogen administration as concentrate or fresh frozen plasma (FFP) results in comparable effects. Blood from six healthy donors was diluted by 60% using lactated Ringer's solution. Aliquots of diluted blood samples were incubated with two different doses of fibrinogen concentrate, FXIII concentrate, the combination of both, or with two different doses of FFP. Using thrombelastometry (ROTEM) blood samples were analyzed at baseline (undiluted), after dilution and after supplementation. Variables were analyzed for changes from baseline, and effects of fibrinogen concentrate alone or combined with FXIII were compared with effects observed with corresponding FFP doses. After 60% in vitro dilution of blood all ROTEM parameters and global coagulation tests changed significantly. Among the substitutes tested FXIII alone had no effect, the combination with fibrinogen improved coagulation time, alpha angle and fibrinogen/fibrin polymerization significantly more than did small-dose fibrinogen alone. After substituting fibrinogen, median values of all ROTEM variables were within the normal range, thereby showing dose dependency but also significant differences (P = 0.027) from corresponding FFP doses (EXTEM MCF FFP small dose [38 (35, 40.3) mm)], which enabled only coagulation time to be shortened to baseline levels. Supplementation of fibrinogen restored all ROTEM parameters after dilution. This effect was partially enhanced by adding FXIII and was significantly stronger than for FFP substitution.

Interaction of a blood coagulation factor on electrically polarized hydroxyapatite surfaces

Although the polarization treatment of hydroxyapatite (HA) remarkably enhances the osteoconductivity, the mechanisms have not yet been completely understood. The interaction of proteins in blood and tissue fluids with biomaterials are reportedly triggers for later cellular responses and played a major role in osteoconductive processes. Considering this, we disclosed the interaction of polarized HA surface with a coagulation factor, fibrin stabilizing factor XIII (FXIII). The HA activated FXIII even in Ca2+ free buffer, based on the SDS-PAGE detections of alpha-polymer and gamma-dimer bands assigned to stabilized fibrin. The Ca2+ ions, possibly released from the HA surfaces, were examined whether they initiate the activation of the FXIII. It was experimentally proved by ICP analysis that the induced large negative charges on the electrically polarized HA significantly increased the released Ca2+ concentration for the short pre-incubation time of 3 min. The more Ca2+ ions released from the negatively charged HA (N-HA) surfaces were more effective in the activation of the FXIII, resulting in the rapider disappearance of the gamma-chain bands in fibrin. The slightly lower Ca2+ concentration in the positively charged HA, compared to the nonpolarized HA activated the FXIII at an almost equal rate. The accelerated activation contributed to the stabilization of fibrin scaffold. Therefore, the polarity difference of the induced charges of the polarized HA surface altered the rate of the FXIII activation. The early stage interaction of the HA surfaces with blood proteins was considered to be an essential process of the accelerated new bone formation near implanted N-HA surface.

Intraspinal hemorrhage in a child with factor XIII deficiency

The rarity of spinal cord injuries and hemorrhages and of fibrin-stabilizing factor XIII deficiency during childhood has induced us to report the case of this two-year-old boy with factor XIII deficiency who presented with cervical intraspinal hemorrhage between the C4 and C7 levels as well as paraplegia presumably following a minor trauma. The findings in this patient, who was brought in two weeks after the appearance of the first symptoms, indicate the importance of early diagnosis and early intervention to minimize the extent of the damage from the injury in such cases. The case also points to the need for close follow-up of patients with factor XIII deficiency for CNS bleeding.

Denaturation-Renaturation of the Fibrin-Stabilizing Factor XIII a-Chain Isolated from Human Placenta. Properties of the Native and Reconstituted Protein

The denaturation-renaturation transition between the native and unfolded states of the dimeric blood coagulation factor XIIIa has been examined by far-UV circular dichroism, fluorescence spectroscopy, activity measurements, sedimentation equilibrium analysis, and size exclusion high performance liquid chromatography. Guanidine hydrochloride and urea-dependent denaturation in the absence and in the presence of 5mM dithioerythritol or glutathione (5mM GSH) exhibit biphasic transitions. The first stage represents a sharp transition characterized by a change in secondary structure without subunit dissociation. This step is accompanied by the irreversible loss of biological activity. The second transition reflects the dissociation and complete unfolding of the protein to a random coil. After loss of biological activity no reactivation can be accomplished under any of the following conditions: (i) denaturation and renaturation under reducing or non-reducing conditions, (ii) variation of the protein concentration and temperature, (iii) addition of specific ligands (Ca2+, substrate), (iv) presence of stabilizing and/or destabilizing agents. Attempts to renature the protein under standard conditions (0.1 M Tris/HCl pH 7.5-9.0, 5mM DTE, 5mM EDTA) lead to refolding intermediates which exhibit a strong tendency to aggregate. A soluble product of reconstitution can be obtained by refolding at low protein concentration, low temperature, and in the presence of small amounts of destabilizing agents such as arginine or urea in the renaturation buffer at pH 7.5 to 9. The spectroscopic and hydrodynamic characterization of the partially reconstituted (non-native inactive) protein shows that partially reconstituted factor XIIIa exhibits the fluorescence properties and the dimeric structure of the native protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Proteinase and proteinase inhibitor localization in the human placenta.

Standard immunoperoxidase techniques were used to investigate the distribution of the intracellular proteinase cathepsin D, two serine proteinase inhibitors--alpha 1-antitrypsin (alpha 1-AT) and alpha 1-antichymotrypsin (alpha 1-AChy)--and plasma fibrin stabilizing factor XIII (FXIII) in paraffin-embedded tissues from early and late intrauterine pregnancy and ectopic pregnancy. Localization of cathepsin D, alpha 1-AT, and alpha 1-AChy was identical in ectopic and intrauterine gestation: there was labeling of villous syncytiotrophoblast and a proportion of Hofbauer cells but no labeling of villous cytotrophoblast. The majority of interstitial extravillous trophoblast yielded negative results, but alpha 1-AT and alpha 1-AChy were consistently demonstrated in endovascular trophoblast. FXIII was not found in any trophoblast population but was demonstrated in Hofbauer cells, stromal fibroblasts, and interstitial dendritic cells. Granular, extracellular FXIII reactivity was present among sheets of infiltrating extravillous trophoblast in ectopic pregnancy but only occasionally in early intrauterine pregnancy. The results document further the heterogeneity of trophoblast, with the endovascular trophoblast forming an immunophenotypically distinct population. Furthermore, the pattern of extravillous trophoblastic invasion of maternal tissues in ectopic pregnancy appears to differ from intrauterine pregnancy; the poor decidualization of tubal mucosa in ectopic pregnancy may play a role in this variation.

Degradation of human plasma fibrin stabilizing factor XIII subunits by human granulocytic proteinases

Decreased activity of fibrin stabilizing factor XIII may occur in diseases with enhanced destruction of granulocytes. Haemorrhage and impaired wound healing may result. It has been shown by means of SDS-polyacrylamide gel electrophoresis that the neutral proteinases from human polymorphonuclear granulocytes, the E lastase L ike P roteinase (ELP), and the C hymotrypsin L ike P roteinase (CLP), are able to digest purified human plasma factor XIII. Both sub-units, a and b , are affected at concentrations which might locally or systemically occur under pathophysiological conditions. Higher concentrations are required for the degradation of subunit b . Depending on the proteinases, the concentration used and the time of incubation, numerous split products were formed. To obtain comparable effects, the concentration of CLP had to be about twice that of ELP. Aprotinin had only a slight inhibitory effect on the two leukocyte proteinases. The results presented indicate that factor XIII is degraded and inactivated by granulocytic proteinases, both subunits being altered by these proteinases. Therefore the determination of subunit b may be helpful in differentiating between the proteolytic effect of thrombin which degrades only subunit a , and the granulocyte proteinases.