Maternal Choline Supplementation Alters Fetal Growth Patterns in a Mouse Model of Placental Insufficiency

Abstract

Impairments in placental development can adversely affect pregnancy outcomes. The bioactive nutrient choline may mitigate some of these impairments, as suggested by data in humans, animals, and human trophoblasts. Herein, we investigated the effects of maternal choline supplementation (MCS) on parameters of fetal growth in a Dlx3+/- (distal-less homeobox 3) mouse model of placental insufficiency. Dlx3+/- female mice were assigned to 1X (control), 2X, or 4X choline intake levels during gestation. Dams were sacrificed at embryonic days E10.5, 12.5, 15.5, and 18.5. At E10.5, placental weight, embryo weight, and placental efficiency were higher in 4X versus 1X choline. Higher concentrations of hepatic and placental betaine were detected in 4X versus 1X choline, and placental betaine was positively associated with embryo weight. Placental mRNA expression of Igf1 was downregulated by 4X (versus 1X) choline at E10.5. No differences in fetal growth parameters were detected at E12.5 and 15.5, whereas a small but significant reduction in fetal weight was detected at E18.5 in 4X versus 1X choline. MCS improved fetal growth during early pregnancy in the Dlx3+/- mice with the compensatory downregulation of Igf1 to slow growth as gestation progressed. Placental betaine may be responsible for the growth-promoting effects of choline.

Keywords: IGF; betaine; choline; fetal growth; placenta; pregnancy.

Figure 1

Fetal and placental growth characteristics by choline treatment (1X control, 2X, and 4X) and Dlx3 genotype. Embryo weight at (A) E10.5, and (B) E18.5. Placental weight at (C) E10.5, and (D) E18.5. Crown-rump length at (E) E10.5 and (F) E18.5. Placental efficiency (defined as embryo weight/placental weight) at (G) E10.5 and (H) E18.5. Data were analyzed using mixed linear models controlling for maternal identifier, fetal sex, and litter size. Values are presented as mean ± SEM. Differing letters denote p ≤ 0.05. † denotes p < 0.10. n = seven to 10 dams per treatment per time point.

Figure 2

mRNA abundance of (A) Igf1, (B) Igf2, (C) Igf1r, (D) Igf2r, and (E) Egfr at E10.5 and E18.5 by maternal choline treatment (1X control, 2X, and 4X) in Dlx3+/− placentas. Fold changes are expressed relative to the housekeeping gene Tbp, with the 1X control group normalized to 1.0. Data were analyzed using mixed linear models controlling for maternal ID, fetal sex, and litter size. Log-transformed data (Igf1 at E10.5) is represented by back-transformed means and 95% confidence intervals. All other values are presented as mean ± SEM. Differing letters denote p ≤ 0.05. † denotes p < 0.10. n = 20 placentas per treatment per time point (two to three per dam).

Figure 3

Relationships between placental choline metabolites, placental gene expression, and fetal and placental growth characteristics. Graphs present data points and regression lines obtained from linear mixed models adjusting for the mother’s ID, fetal genotype and sex, and litter size, with the intercept set at average litter size. (A) Placental betaine concentrations and embryo weight at E10.5; (B) Placental betaine and placental weight at E18.5; (C) Placental choline and placental efficiency at E12.5; (D) Placental choline and placental weight at E15.5; (E) Placental Igf1 expression and embryo weight at E10.5; (F) Placental Egfr expression and embryo weight at E10.5.