Acidic Citrate Stabilizes Blood Samples for Assay of Total Homocysteine

Willems, Huub P. J.; Bos, Gerard M.J.; Gerrits, W. B. J.; Heijer, Martin den; Vloet, Stephanie; Blom, Henk J.

doi:10.1093/clinchem/44.2.342

Cited by 58 publications

(16 citation statements)

References 14 publications

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“…Homocysteine in acidified citrated plasma (21) was analysed using a fluorescence polarization immunoassay on an IMx ® unit (Abbott Laboratories, IL, USA). Total blood DNA was extracted and purified from 200 μl of whole blood anticoagulated with EDTA, using the QIAamp DNA blood mini kit according to the manufacturer's instructions (Qiagen, Valencia, CA, USA).…”

Section: Homocysteine Assay Dna Extraction and Mthfr Genotypingmentioning

confidence: 99%

Association of total plasma homocysteine with methylenetetrahydrofolate reductase genotypes 677C>T, 1298A>C, and 1793G>A and the corresponding haplotypes in Swedish children and adolescents

Böttiger¹,

Hurtig-Wennlöf²,

Sjöstróm³

et al. 2007

Int J Mol Med

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We studied 692 Swedish children and adolescents (aged 9-10 or 15-16 years, respectively), in order to evaluate the effect of the methylenetetrahydrofolate reductase (MTHFR) 677C>T, 1298A>C, and 1793G>A polymorphisms on total plasma homocysteine concentrations (tHcy). Genotyping was performed with Pyrosequencing™ technology. The MTHFR 677C>T polymorphism was associated with increased tHcy concentrations in both the children and the adolescents (P<0.001 for both age groups) in both genders. The effect of MTHFR 1298A>C was studied separately in subjects with the 677CC and 677CT genotypes, and the 1298C allele was found to be associated with higher tHcy levels both when children were stratified according to 677C>T genotypes, and when using haplotype analyses and diplotype reconstructions. The 1793A allele was in complete linkage disequilibrium with the 1298C allele. It was still possible to show that the 1793A allele was associated with lower tHcy levels, statistically significant in the adolescents. In conclusion, a haplotype-based approach was slightly superior in explaining the genetic interaction on tHcy plasma levels in children and adolescents than a simple genotype based approach (R 2 adj 0.44 vs. 0.40). The major genetic impact on tHcy concentrations is attributable to the MTHFR 677C>T polymorphism. The common 1298A>C polymorphism had a minor elevating effect on tHcy, whereas the 1793G>A polymorphism had a lowering effect on tHcy.

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Section: Homocysteine Assay Dna Extraction and Mthfr Genotypingmentioning

confidence: 99%

Association of total plasma homocysteine with methylenetetrahydrofolate reductase genotypes 677C>T, 1298A>C, and 1793G>A and the corresponding haplotypes in Swedish children and adolescents

Böttiger¹,

Hurtig-Wennlöf²,

Sjöstróm³

et al. 2007

Int J Mol Med

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“…Non-fasting blood samples were drawn from the antecubital vein in 5-mL Stabilyte ® (Monovette ® ) tubes for determination of homocysteine. Withdrawal on acidic citrate is a good alternative for blood tubes on crushed ice, when screening patients in epidemiological field studies, because total homocysteine (tHcy) concentrations stay stable for 6 h [19]. The Stabilyte ® blood sample was centrifuged at 2000 r.p.m.…”

Section: Determination Of Homocysteine Concentrationmentioning

confidence: 99%

The relation between Helicobacter pylori and atherosclerosis cannot be explained by a high homocysteine concentration

Bloemenkamp

Mali

Tanis

et al. 2002

Eur J Clin Investigation

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“…Whole blood at room temperature will increase its total homocysteine (tHcy) in plasma for about 0.5 to 1 mol/L per hour. 19,20 Consequently, for accurate homocysteine determination blood needs to be centrifuged immediately or put on ice. This procedure is cumbersome in general practice, in particular in large epidemiological studies.…”

Section: Blood Cellsmentioning

confidence: 99%

Consequences of Homocysteine Export and Oxidation in the Vascular System

Blom

2000

Semin Thromb Hemost

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The risk for arteriosclerosis and thrombosis of patients with severe hyperhomocysteinemia is reduced by homocysteine-lowering therapy. Whether this is the case in patients with mild hyperhomocysteinemia remains to be proved. Another challenge for researchers is to establish a satisfying pathological mechanism of the vasotoxicity of a disturbed homocysteine metabolism. Unfortunately, most in vitro studies use physiologically irrelevant concentrations or forms, or both, of homocysteine. The role of the different oxidized and reduced forms of homocysteine in its metabolism has gained little attention. In the cell, homocysteine is mainly present in its reduced form. In this article export of homocysteine out of the cell is reported to be regulated by a "reduced-homocysteine carrier." In vitro endothelial cells export homocysteine at a constant rate in a folate dose-dependent matter. Even at high-normal folate levels, endothelial cells export homocysteine. As soon as homocysteine is exported out of the cell, it will be oxidized to a disulfide with any compound containing a thiol function or undergo a disulfide exchange reaction, both resulting in formation of disulfides of homocysteine. Consequently, in plasma, about 99% of homocysteine is bound to disulfides. Before homocysteine can be metabolized, it needs to be taken up by the cell via carriers, channels, or receptors recognizing the different homocysteine disulfides. In the cell, the homocysteine disulfides are reduced, liberating homocysteine in its reduced form. Next, homocysteine can be metabolized after binding to the homocysteine-converting enzymes. In particular, the liver and kidney supposedly take up and metabolize significant amounts of homocysteine.

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Acidic Citrate Stabilizes Blood Samples for Assay of Total Homocysteine

Cited by 58 publications

References 14 publications

Association of total plasma homocysteine with methylenetetrahydrofolate reductase genotypes 677C>T, 1298A>C, and 1793G>A and the corresponding haplotypes in Swedish children and adolescents

Association of total plasma homocysteine with methylenetetrahydrofolate reductase genotypes 677C>T, 1298A>C, and 1793G>A and the corresponding haplotypes in Swedish children and adolescents

The relation between Helicobacter pylori and atherosclerosis cannot be explained by a high homocysteine concentration

Consequences of Homocysteine Export and Oxidation in the Vascular System

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