title: Evaluation of bidirectional transfer of plasma DNA through placenta.
abstract: To clarify the origin of cell-free fetal DNA in maternal plasma, we analyzed bidirectional transfer of plasma DNA between fetus and mother. We analyzed maternal and fetal plasma DNA obtained from 15 pregnant women at the time of Cesarean section. The subjects were five patients with preeclampsia and 10 gestational-age-matched normal controls. DNA was extracted from 1.5-ml plasma samples and the cellular fraction of maternal and umbilical blood. Seven polymorphic marker genes were analyzed. The relative concentration of fetal DNA in maternal plasma and maternal DNA in cord blood were evaluated. The relative concentration of maternal DNA in fetal circulation (median, 0.9%; range, 0.2-8.4%) was significantly lower than that of fetal DNA in maternal blood (14.3%, 2.3-64%), with P=0.007. The relative concentration of maternal DNA in fetal blood was not affected by preeclampsia. These findings indicate that cell-free DNA is unequally transferred through the placenta. The structural characteristics of the placenta suggest that the majority of cell-free fetal DNA in maternal plasma is derived from villous trophoblasts.
authors.affiliation: Department of Obstetrics and Gynecology, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, 142-8666, Tokyo, Japan. sekizawa@med.showa-u.ac.jp
authors.forename: Akihiko
authors.initials: A
authors.lastname: Sekizawa
authors.forename: Kaori
authors.initials: K
authors.lastname: Yokokawa
authors.forename: Yumi
authors.initials: Y
authors.lastname: Sugito
authors.forename: Mariko
authors.initials: M
authors.lastname: Iwasaki
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Yukimoto
authors.forename: Kiyotake
authors.initials: K
authors.lastname: Ichizuka
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Saito
authors.forename: Takashi
authors.initials: T
authors.lastname: Okai
mesh_terms: D004247:DNA / Q000097:blood*; D005260:Female; D005312:Fetal Blood / Q000378:metabolism*; D005819:Genetic Markers; D006801:Humans; D008431:Maternal-Fetal Exchange / Q000235:genetics*; D010920:Placenta / Q000378:metabolism*; D011110:Polymorphism, Genetic; D011247:Pregnancy; D020080:Tandem Repeat Sequences
chemical_list: D005819:Genetic Markers; D004247:DNA