title: Hypomethylation of serum blood clot DNA, but not plasma EDTA-blood cell pellet DNA, from vitamin B12-deficient subjects.
abstract: Vitamin B12, a co-factor in methyl-group transfer, is important in maintaining DNA (deoxycytidine) methylation. Using two independent assays we examined the effect of vitamin B12-deficiency (plasma vitamin B12<148 pmol/L) on DNA methylation in women of childbearing age. Coagulated blood clot DNA from vitamin B12-deficient women had significantly (p<0.001) lower percentage deoxycytidine methylation (3.23±0.66%; n = 248) and greater [3 H]methyl-acceptance (42,859±9,699 cpm; n = 17) than DNA from B12-replete women (4.44±0.18%; n = 128 and 26,049±2,814 cpm; n = 11) [correlation between assays: r = -0.8538; p<0.001; n = 28]. In contrast, uncoagulated EDTA-blood cell pellet DNA from vitamin B12-deficient and B12-replete women exhibited similar percentage methylation (4.45±0.15%; n = 77 vs. 4.47±0.15%; n = 47) and [3 H]methyl-acceptance (27,378±4,094 cpm; n = 17 vs. 26,610±2,292 cpm; n = 11). Therefore, in simultaneously collected paired blood samples, vitamin B12-deficiency was associated with decreased DNA methylation only in coagulated samples. These findings highlight the importance of sample collection methods in epigenetic studies, and the potential impact biological processes can have on DNA methylation during collection.
authors.affiliation: Biomedical Mass Spectrometry Laboratory, Clinical and Translational Science Institute, University of Florida, Gainesville, Florida, United States of America. epq@ufl.edu
authors.forename: Eoin P
authors.initials: EP
authors.lastname: Quinlivan
authors.forename: Krista S
authors.initials: KS
authors.lastname: Crider
authors.forename: Jiang-Hui
authors.initials: JH
authors.lastname: Zhu
authors.forename: David R
authors.initials: DR
authors.lastname: Maneval
authors.forename: Ling
authors.initials: L
authors.lastname: Hao
authors.forename: Zhu
authors.initials: Z
authors.lastname: Li
authors.forename: Sonja A
authors.initials: SA
authors.lastname: Rasmussen
authors.forename: R J
authors.initials: RJ
authors.lastname: Berry
authors.forename: Lynn B
authors.initials: LB
authors.lastname: Bailey
mesh_terms: D000328:Adult; D004247:DNA / Q000097:blood*; D019175:DNA Methylation; D003841:Deoxycytidine / Q000378:metabolism; D005260:Female; D005492:Folic Acid / Q000097:blood; D006801:Humans; D014805:Vitamin B 12 / Q000097:blood; D014806:Vitamin B 12 Deficiency / Q000097:blood* / Q000235:genetics*
chemical_list: D003841:Deoxycytidine; D004247:DNA; D005492:Folic Acid; D014805:Vitamin B 12