Blood folate status and expression of proteins involved in immune function, inflammation, and coagulation: biochemical and proteomic changes in the plasma of humans in response to long-term synthetic folic acid supplementation

Susan J. Duthie, Graham Horgan, Baukje De Roos, Garry Rucklidge, Martin Reid, Gary Duncan, Lynn Pirie, Graham P. Basten, Hilary J. Powers

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    Abstract

    We used plasma proteomics to identify human proteins responsive to folate status. Plasma was collected from subjects treated with placebo or 1.2 mg of folic acid daily for 12 weeks in a randomized controlled trial. Homocysteine and folate were measured by immunoassay and uracil misincorporation by electrophoresis. The plasma proteome was assessed by 2-D gel electrophoresis, and proteins were identified by LC MS/MS. 5-methylTHF increased 5-fold (P = 0.000003) in response to intervention. Red cell folate doubled (P = 0.013), and lymphocyte folate increased 44% (P = 0.0001). Hcy and uracil dropped 22% (P= 0.0005) and 25% (P= 0.05), respectively. ApoE A-1, alpha-1-antichymotrypsin, antithrombin, and serum amyloid P were downregulated, while albumin, IgM C, and complement C3 were upregulated (P < 0.05). More than 60 proteins were significantly associated with folate pre- and postintervention (P < 0.01). These were categorized into metabolic pathways related to complement fixation (e.g., C1, C3, C4, Factor H, Factor 1, Factor B, clusterin), coagulation (e.g., antithrombin, alpha-1-antitrypsin, kininogen) and mineral transport (e.g., transthyretin, haptoglobin, ceruloplasmin). Low folate status pre- and post-treatment were associated with lower levels of proteins involved in activation and regulation of immune function and coagulation. Supplementation with synthetic folic acid increased expression of these proteins but did not substantially disrupt the balance of these pathways.

    Original languageEnglish
    Pages (from-to)1941-1950
    Number of pages10
    JournalJournal of Proteome Research
    Volume9
    Issue number4
    Early online date9 Feb 2010
    DOIs
    Publication statusPublished - 5 Apr 2010

    Keywords

    • synthetic folic acid supplementation
    • human study
    • folate status
    • plasma proteomics
    • immune function
    • neural-tube defects
    • total homocysteine concentrations
    • United-States
    • serum folate
    • healthy-volunteers
    • food fortification
    • disease
    • cancer
    • trends
    • vitronectin

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