TY - JOUR
T1 - Folic Acid Impairs the Uptake of 5-Methyltetrahydrofolate in Human Umbilical Vascular Endothelial Cells
AU - Smith, Desiree
AU - Hornstra, Jacqueline
AU - Rocha, Monica
AU - Jansen, Gerrit
AU - Assaraf, Yehuda
AU - Lasry, Inbal
AU - Blom, Henk
AU - Smulders, Yvo M.
PY - 2017/10/1
Y1 - 2017/10/1
N2 - Background: Adequate folate status supports endothelial structure and function. Folic acid (FA), an oxidized synthetic folate, which is present in the plasma of patients consuming fortified food or FA supplements, may impair cellular uptake of physiological, reduced folates. We studied the effect of FA on uptake of the dominant circulatory folate, 5-methyltetrahydrofolate (5MTHF) in endothelial cells. Methods and Results: For short-term effects of FA, primary human umbilical vein endothelial cells (HUVECs) were maintained in growth medium containing 200 nM 5MTHF and preincubated with 20 nM FA 10 minutes before the 5MTHF uptake assessment. For long-term effects, HUVECs were cultured for 3 passages in growth medium containing either 200 nM 5MTHF, or a combination of 100 nM 5MTHF and 100 nM FA. 5MTHF uptake was assessed after exposing cells to 200 nM [ 13 C 5 ]-5MTHF, after which intracellular [ 13 C 5 ]-5MTHF was quantified using liquid chromatography/tandem mass spectrometry. Acute FA exposure caused a 57% reduction in 5MTHF uptake compared with control conditions (51 ± 12 vs. 22 ± 7 fmol·min -1 ·mg -1 protein; P = 0.01). Long-term exposure to FA reduced 5MTHF uptake by 41% (51 ± 12 vs. 30 ± 11 fmol·min -1 ·mg -1 protein; P = 0.05) and reduced total cellular 5MTHF levels by 47 ± 21% in HUVEC (P = 0.02). Conclusion: Unmetabolized FA, which appears in the plasma after consumption of fortified food or FA supplements, may impair uptake of 5MTHF, the dominant bioactive form of folate, in HUVEC.
AB - Background: Adequate folate status supports endothelial structure and function. Folic acid (FA), an oxidized synthetic folate, which is present in the plasma of patients consuming fortified food or FA supplements, may impair cellular uptake of physiological, reduced folates. We studied the effect of FA on uptake of the dominant circulatory folate, 5-methyltetrahydrofolate (5MTHF) in endothelial cells. Methods and Results: For short-term effects of FA, primary human umbilical vein endothelial cells (HUVECs) were maintained in growth medium containing 200 nM 5MTHF and preincubated with 20 nM FA 10 minutes before the 5MTHF uptake assessment. For long-term effects, HUVECs were cultured for 3 passages in growth medium containing either 200 nM 5MTHF, or a combination of 100 nM 5MTHF and 100 nM FA. 5MTHF uptake was assessed after exposing cells to 200 nM [ 13 C 5 ]-5MTHF, after which intracellular [ 13 C 5 ]-5MTHF was quantified using liquid chromatography/tandem mass spectrometry. Acute FA exposure caused a 57% reduction in 5MTHF uptake compared with control conditions (51 ± 12 vs. 22 ± 7 fmol·min -1 ·mg -1 protein; P = 0.01). Long-term exposure to FA reduced 5MTHF uptake by 41% (51 ± 12 vs. 30 ± 11 fmol·min -1 ·mg -1 protein; P = 0.05) and reduced total cellular 5MTHF levels by 47 ± 21% in HUVEC (P = 0.02). Conclusion: Unmetabolized FA, which appears in the plasma after consumption of fortified food or FA supplements, may impair uptake of 5MTHF, the dominant bioactive form of folate, in HUVEC.
KW - endothelial cells
KW - folate
KW - metabolism
KW - molecular biology
UR - http://www.scopus.com/inward/record.url?scp=85032219253&partnerID=8YFLogxK
U2 - https://doi.org/10.1097/FJC.0000000000000514
DO - https://doi.org/10.1097/FJC.0000000000000514
M3 - Article
C2 - 28991880
SN - 0160-2446
VL - 70
SP - 271
EP - 275
JO - Journal of Cardiovascular Pharmacology
JF - Journal of Cardiovascular Pharmacology
IS - 4
ER -