Blood, 1 January 2003, Vol. 101, No. 1, pp. 371-371
CORRESPONDENCE
To the editor:
Factor XIII activation by thrombin depends on FXIIIVal34Leu
genotype
Brummel et al1 reported interesting
results on different thrombin functions during tissue factor-induced
whole blood coagulation. Thrombin generation, platelet activation, and
activation of fibrinogen, factor V, and factor XIII (FXIII) were
analyzed. FXIII activation was reported to occur slightly prior to
fibrinopeptide A (FPA) release at a rate of 10.3 ± 0.9 nM/min and at
a thrombin concentration of 0.84 ± 0.28 nM. However, these results
by Brummel et al1 must be interpreted with caution.
FXIII activation is known to be strongly influenced by a common
polymorphism in the FXIII A-subunit gene
(FXIIIVal34Leu),2,3 which has been shown to be protective
against myocardial infarction,4 ischemic
stroke,5 and deep vein thrombosis.6
This common G>T point mutation in codon 34, exon 2 of
the A-subunit gene, which codes for the Val
Leu change, is
only 3 amino acids from the thrombin activation site. The Leu allele is
associated with increased cross-linking activity determined by an
incorporation assay3,7 and a reduced clot formation time
measured by thrombelastography.8 Kinetic studies on the
activation reaction of FXIII by thrombin revealed increased catalytic
efficiency (kcat/Km)
for FXIII Leu34 compared with Val34.9,10
Activation of FXIII Leu34 occurred at a similar rate as FPA release;
FXIII Val34 was activated slower.9 Based on these
findings, altered fibrin structures9 and wasteful, premature FXIII activation10 have been proposed as
mechanisms of the protective effect of FXIIIVal34Leu.
Knowledge of the FXIIIVal34Leu genotype in these 6 individuals
taking part in the study by Brummel et al1 is essential. Because of the high allele frequency of this polymorphism
(approximately 0.25 for the Leu allele4) in the general
population and the significant kinetic differences between genotypes,
the Val34Leu polymorphism has to be taken into account when FXIII
activation rates are studied.
Verena Schroeder and Hans P. Kohler
Correspondence: Hans P. Kohler, Laboratory for Thrombosis
Research, Department of Clinical Research, Kinderklinik G3, Room 835, University Hospital, Inselspital, 3010 Bern, Switzerland; e-mail:
hanspeter.kohler{at}insel.ch
References
1.
Brummel KE, Paradis SG, Butenas S, Mann KG.
Thrombin functions during tissue factor-induced blood coagulation.
Blood.
2002;100:148-152[Abstract/Free Full Text].
2.
Anwar R, Gallivan L, Edmonds SD, Markham AF.
Genotype/phenotype correlations for coagulation factor XIII: specific normal polymorphisms are associated with high or low factor XIII specific activity.
Blood.
1999;93:897-905[Abstract/Free Full Text].
3.
Kohler HP, Ariëns RAS, Whitaker P, Grant PJ.
A common coding polymorphism in the factor XIII A-subunit gene (FXIIIVal34Leu) affects cross-linking activity [letter].
Thromb Haemost.
1998;80:704[Medline]
[Order article via Infotrieve].
4.
Kohler HP, Stickland MH, Ossei-Gerning N, Carter AM, Mikkola H, Grant PJ.
Association of a common polymorphism in the factor XIII gene with myocardial infarction.
Thromb Haemost.
1998;79:8-13[Medline]
[Order article via Infotrieve].
5.
Elbaz A, Poirier O, Canaple S, Chédru F, Cambien F, Amarenco P.
The association between the Val34Leu polymorphism in the factor XIII gene and brain infarction.
Blood.
2000;95:586-591[Abstract/Free Full Text].
6.
Catto AJ, Kohler HP, Coore J, Mansfield MW, Stickland MH, Grant PJ.
Association of a common polymorphism in the factor XIII gene with venous thrombosis.
Blood.
1999;93:906-908[Abstract/Free Full Text].
7.
Schroeder V, Kohler HP.
Effect of factor XIII Val34Leu on 
2-antiplasmin incorporation into fibrin [letter].
Thromb Haemost.
2000;84:1128-1130[Medline]
[Order article via Infotrieve].
8.
Schroeder V, Chatterjee T, Kohler HP.
Influence of blood coagulation factor XIII and FXIII Val34Leu on plasma clot formation measured by thrombelastography.
Thromb Res.
2001;104:467-474[CrossRef][Medline]
[Order article via Infotrieve].
9.
Ariëns RAS, Philippou H, Chandrasekaran N, Weisel JW, Lane DA, Grant PJ.
The factor XIII V34L polymorphism accelerates thrombin activation of factor XIII and affects cross-linked fibrin structure.
Blood.
2000;96:988-995[Abstract/Free Full Text].
10.
Trumbo TA, Maurer MC.
Examining thrombin hydrolysis of the factor XIII activation peptide segment leads to a proposal for explaining the cardioprotective effects observed with the factor XIII V34L mutation.
J Biol Chem.
2000;275:20627-20631[Abstract/Free Full Text].
Response:
Factor XIII genotypes and phenotypes
Drs Schroeder and Kohler raise an interesting point
regarding the activation of factor XIII (FXIII) in whole blood
concerning the Val34Leu polymorphism. They cite the work of
Ariëns et al1 in which a 2.2- to 2.5-fold increase
in the catalytic efficiency of thrombin toward homogenous factor XIII
Leu34 over Val34 was observed in an in vitro assay system using
purified thrombin and fibrinogen. We have observed that FXIII
activation in Leu34 carriers (12 heterozygotes, 2 homozygotes) is
faster (~1.4 fold) than in Val34/homozygotes (23 individuals) in a
Simplate (Organon Teknika, Durham, NC) bleeding-time blood
model.2 Ariëns et al1 also observed
that the Val34 release proceeded more slowly than fibrinopeptide A
(FPA) release, whereas Leu34 release was at a rate similar to FPA. Drs
Schroeder and Kohler seem to be implying that given the allelic
frequency in the population (0.25) of Leu34 versus Val34 we should have
observed, in a random population, a slower activation of FXIII than FPA
release. Although it is conceivable that some of the 6 individuals
studied are Leu34 variants (probability 0.32), the difference between
the alleles with respect to FPA release and factor XIII activation
would most likely fall within the error observed.3 The
contributions of Leu34 FXIII versus Val34 FXIII in whole blood is a
complicated issue because the plasma contribution from each of the
alleles and their turnover rates are not known. Thus, genotyping alone
would not be sufficient to establish the plasma concentrations of the
2 products.
Caution must be taken when individual genetic factors are used without
considering the entire environment in which the biologic reaction takes
place. Heterogeneity in the healthy population is a
consequence of many genetic and environmental confounders and these
variations do not necessarily lead to hemostatic changes. In healthy
individuals, alterations in plasma coagulation factor levels range over
± 50% of the mean plasma value.4 The genotype and
environment may alter both the qualitative and quantitative properties
for every reactant in blood. This is illustrated by experiments in
which FV Leiden is combined with reduced levels of tissue factor
pathway inhibitor (TFPI). From in vitro measurements, van't Veer et
al5 hypothesized that reduced expression of TFPI would
enhance the prothrombotic effect of FV Leiden. Eitzman et al6 demonstrated that reduced expression of TFPI in FV
Leiden transgenic mice is associated with thrombosis.
Predicting how coagulation should proceed in vivo from results obtained
from purified systems has proven problematic. The order of events of
fibrin formation in nonanticoagulated whole blood is not sequential,
occurring as an integrated process involving FPA release, virtually
simultaneous FXIII activation, and partial FPB release.7
This result is not consistent with results obtained in anticoagulated
plasmas8,9 and purified protein systems.10 Our study3 involves the complex system of minimally altered whole blood and is thus a composite of all influences
(genotype/phenotype and qualitative/quantitative). It is remarkable
that healthy volunteers are, by and large, consistent in their response
to tissue factor.
Kathleen E. Brummel and Kenneth G. Mann
Correspondence: Kenneth G. Mann, Department of Biochemistry,
University of Vermont, 89 Beaumont Avenue, Given C401, Burlington, VT
05405; e-mail: kmann{at}zoo.uvm.edu
References
1.
Ariëns RA, Philippou H, Nagaswami C, Weisel JW, Lane DA, Grant PJ.
The factor XIII V34L polymorphism accelerates thrombin activation of factor XIII and affects cross-linked fibrin structure.
Blood.
2000;96:988-995[Abstract/Free Full Text].
2.
Undas A, Brummel KE, Musial J, Mann KG, Szczeklik A.
Aspirin and cardioprotective effects of the Val34Leu polymorphism of factor XIII [abstract].
Circulation.
2001;104:11-12.
3.
Brummel KE, Paradis SG, Butenas S, Mann KG.
Thrombin functions during tissue factor-induced blood coagulation.
Blood.
2002;100:148-152[Abstract/Free Full Text].
4.
Butenas S, van't Veer C, Mann KG.
"Normal" thrombin generation.
Blood.
1999;94:2169-2178[Abstract/Free Full Text].
5.
van't Veer C, Kalafatis M, Bertina RM, Simioni P, Mann KG.
Increased tissue factor-initiated prothrombin activation as a result of the Arg506Gln mutation in factor VLEIDEN.
J Biol Chem.
1997;272:20721-20729[Abstract/Free Full Text].
6.
Eitzman DT, Westrick RJ, Bi X, et al.
Lethal perinatal thrombosis in mice resulting from the interaction of tissue factor pathway inhibitor deficiency and factor V Leiden.
Circulation.
2002;105:2139-2142[Abstract/Free Full Text].
7.
Brummel KE, Butenas S, Mann KG.
An integrated study of fibrinogen during blood coagulation.
J Biol Chem.
1999;274:22862-22870[Abstract/Free Full Text].
8.
Ebert RF, Bell WR.
Assay of human fibrinopeptides by high-performance liquid chromatography.
Anal Biochem.
1985;148:70-78[CrossRef][Medline]
[Order article via Infotrieve].
9.
Koehn JA, Canfield RE.
Purification of human fibrinopeptides by high-performance liquid chromatography.
Anal Biochem.
1981;116:349-356[CrossRef][Medline]
[Order article via Infotrieve].
10.
Southan C, Thompson E, Lane DA.
Direct analysis of plasma fibrinogen-derived fibrinopeptides by high-performance liquid chromatography.
Thromb Res.
1986;43:195-204[CrossRef][Medline]
[Order article via Infotrieve].
