title: Pregnancy alters choline dynamics: results of a randomized trial using stable isotope methodology in pregnant and nonpregnant women.
abstract: BACKGROUND
  Although biomarkers of choline metabolism are altered by pregnancy, little is known about the influence of human pregnancy on the dynamics of choline-related metabolic processes.
  
  
  OBJECTIVE
  This study used stable isotope methodology to examine the effects of pregnancy on choline partitioning and the metabolic activity of choline-related pathways.
  
  
  METHODS
  Healthy third-trimester pregnant (n = 26; initially week 27 of gestation) and nonpregnant (n = 21) women consumed 22% of their total choline intake (480 or 930 mg/d) as methyl-d9-choline for the final 6 wk of a 12-wk feeding study.
  
  
  RESULTS
  Plasma d9-betaine:d9-phosphatidylcholine (PC) was lower (P ≤ 0.04) in pregnant than in nonpregnant women, suggesting greater partitioning of choline into the cytidine diphosphate-choline (CDP-choline) PC biosynthetic pathway relative to betaine synthesis during pregnancy. Pregnant women also used more choline-derived methyl groups for PC synthesis via phosphatidylethanolamine N-methyltransferase (PEMT) as indicated by comparable increases in PEMT-PC enrichment in pregnant and nonpregnant women despite unequal (pregnant > nonpregnant; P < 0.001) PC pool sizes. Pregnancy enhanced the hydrolysis of PEMT-PC to free choline as shown by greater (P < 0.001) plasma d3-choline:d3-PC. Notably, d3-PC enrichment increased (P ≤ 0.011) incrementally from maternal to placental to fetal compartments, signifying the selective transfer of PEMT-PC to the fetus.
  
  
  CONCLUSIONS
  The enhanced use of choline for PC production via both the CDP-choline and PEMT pathways shows the substantial demand for choline during late pregnancy. Selective partitioning of PEMT-PC to the fetal compartment may imply a unique requirement of PEMT-PC by the developing fetus.
authors.affiliation: Division of Nutritional Sciences, Cornell University, Ithaca, NY (JY, XJ, AAW, OVM, JTB, and MAC); the Family & Consumer Sciences-Nutrition, Shepherd University, Shepherdstown, WV (CAP); the Department of Medicine and Division of Hematology, University of Colorado School of Medicine, Aurora, CO (SPS and RHA); and the Department of Food Science and Human Nutrition, University of Florida, Gainesville, FL (JFG).
authors.forename: Jian
authors.initials: J
authors.lastname: Yan
authors.forename: Xinyin
authors.initials: X
authors.lastname: Jiang
authors.forename: Allyson A
authors.initials: AA
authors.lastname: West
authors.forename: Cydne A
authors.initials: CA
authors.lastname: Perry
authors.forename: Olga V
authors.initials: OV
authors.lastname: Malysheva
authors.forename: J Thomas
authors.initials: JT
authors.lastname: Brenna
authors.forename: Sally P
authors.initials: SP
authors.lastname: Stabler
authors.forename: Robert H
authors.initials: RH
authors.lastname: Allen
authors.forename: Jesse F
authors.initials: JF
authors.lastname: Gregory
authors.forename: Marie A
authors.initials: MA
authors.lastname: Caudill
mesh_terms: D000328:Adult; D001622:Betaine / Q000097:blood; D002794:Choline / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000097:blood / Q000378:metabolism*; D003903:Deuterium; D004032:Diet; D019587:Dietary Supplements; D005260:Female; D005312:Fetal Blood; D006801:Humans; D006868:Hydrolysis; D039382:Maternal Nutritional Physiological Phenomena; D008431:Maternal-Fetal Exchange; D008745:Methylation; D010713:Phosphatidylcholines / Q000097:blood; D050918:Phosphatidylethanolamine N-Methyltransferase / Q000378:metabolism; D010920:Placenta / Q000378:metabolism; D011247:Pregnancy / Q000097:blood / Q000378:metabolism*; D011263:Pregnancy Trimester, Third; D055815:Young Adult
chemical_list: D010713:Phosphatidylcholines; C017506:methylcholine; D001622:Betaine; D003903:Deuterium; D050918:Phosphatidylethanolamine N-Methyltransferase; D002794:Choline