Choline: Exploring the Growing Science on Its Benefits for Moms and Babies

The importance of ensuring adequate choline intakes during pregnancy is increasingly recognized. Choline is critical for a number of physiological processes during the prenatal period with roles in membrane biosynthesis and tissue expansion, neurotransmission and brain development, and methyl group donation and gene expression. Studies in animals and humans have shown that supplementing the maternal diet with additional choline improves several pregnancy outcomes and protects against certain neural and metabolic insults. Most pregnant women in the U.S. are not achieving choline intake recommendations of 450 mg/day and would likely benefit from boosting their choline intakes through dietary and/or supplemental approaches

Maternal betaine supplementation affects fetal growth and lipid metabolism of highfat fed mice in a temporal-specific manner

Background/objectives: Maternal obesity increases the risk of gestational diabetes mellitus (GDM), which results in fetal overgrowth and long-lasting metabolic dysfunctioning in the offspring. Previous studies show that maternal choline supplementation normalizes fetal growth and adiposity of progeny from obese mice. This study examines whether supplementation of betaine, a choline derivative, has positive effects on fetal metabolic outcomes in mouse progeny exposed to maternal obesity and GDM. Methods: C57BL/6J mice were fed either a high-fat (HF) diet or a control (normal-fat, NF) diet and received either 1% betaine (BS) or control untreated (BC) drinking water 4–6 weeks before timed-mating and throughout gestation. Maternal, placental, and fetal samples were collected for metabolite and gene-expression assays. Results: At E12.5, BS prevented fetal and placental overgrowth and downregulated glucose and fatty acid transporters (Glut1 and Fatp1) and the growth-promoting insulin-like growth factor 2 (Igf2) and its receptor Igf1r in the placenta of HF, glucose-intolerant dams (P \u3c 0.05). However, these effects disappeared at E17.5. At E17.5, BS reduced fetal adiposity and prevented liver triglyceride overaccumulation in HF versus NF fetuses (P \u3c 0.05). BS fetal livers had enhanced mRNA expression of microsomal triglyceride transfer protein (Mttp) (P \u3c 0.01), which promotes VLDL synthesis and secretion. Although we previously reported that maternal choline supplementation downregulated mRNA expression of genes involved in de novo lipogenesis in fetal livers, such alterations were not observed with BS, suggesting differential effects of betaine and choline on fetal gene expression. Conclusion: We propose a temporal-specific mechanism by which maternal BS influences fetal growth and lipid metabolic outcomes of HF mice during prenatal development

Maternal Choline Supplementation during Normal Murine Pregnancy Alters the Placental Epigenome: Results of an Exploratory Study

The placental epigenome regulates processes that affect placental and fetal development, and could be mediating some of the reported effects of maternal choline supplementation (MCS) on placental vascular development and nutrient delivery. As an extension of work previously conducted in pregnant mice, the current study sought to explore the effects of MCS on various epigenetic markers in the placenta. RNA and DNA were extracted from placentas collected on embryonic day 15.5 from pregnant mice fed a 1X or 4X choline diet, and were subjected to genome-wide sequencing procedures or mass-spectrometry-based assays to examine placental imprinted gene expression, DNA methylation patterns, and microRNA (miRNA) abundance. MCS yielded a higher (fold change = 1.63-2.25) expression of four imprinted genes (Ampd3, Tfpi2, Gatm and Aqp1) in the female placentas and a lower (fold change = 0.46–0.62) expression of three imprinted genes (Dcn, Qpct and Tnfrsf23) in the male placentas (false discovery rate (FDR) \u3c 0.05 for both sexes). Methylation in the promoter regions of these genes and global placental DNA methylation were also affected (p \u3c 0.05). Additionally, a lower (fold change = 0.3; Punadjusted = 2.05 x 10; FDR = 0.13) abundance of miR-2137 and a higher (fold change = 1.25–3.92; p \u3c 0.05) expression of its target genes were detected in the 4X choline placentas. These data demonstrate that the placental epigenome is responsive to maternal choline intake during murine pregnancy and likely mediates some of the previously described choline-induced effects on placental and fetal outcomes

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

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

Maternal Choline Supplementation Modulates Placental Markers of Inflammation, Angiogenesis, and Apoptosis in a Mouse Model of Placental Insufficiency

Dlx3 (distal-less homeobox 3) haploinsufficiency in mice has been shown to result in restricted fetal growth and placental defects. We previously showed that maternal choline supplementation (4X versus 1X choline) in the Dlx3+/�� mouse increased fetal and placental growth in mid-gestation. The current study sought to test the hypothesis that prenatal choline would modulate indicators of placenta function and development. Pregnant Dlx3+/�� mice consuming 1X (control), 2X, or 4X choline from conception were sacrificed at embryonic (E) days E10.5, E12.5, E15.5, and E18.5, and placentas and embryos were harvested. Data were analyzed separately for each gestational day controlling for litter size, fetal genotype (except for models including only +/�� pups), and fetal sex (except when data were stratified by this variable). 4X choline tended to increase (p \u3c 0.1) placental labyrinth size at E10.5 and decrease (p \u3c 0.05) placental apoptosis at E12.5. Choline supplementation decreased (p \u3c 0.05) expression of pro-angiogenic genes Eng (E10.5, E12.5, and E15.5), and Vegf (E12.5, E15.5); and pro-inflammatory genes Il1b (at E15.5 and 18.5), Tnfa (at E12.5) and Nfkb (at E15.5) in a fetal sex-dependent manner. These findings provide support for a modulatory effect of maternal choline supplementation on biomarkers of placental function and development in a mouse model of placental insufficienc

Effect of Choline Forms and Gut Microbiota Composition on Trimethylamine-N-Oxide Response in Healthy Men

Background: Trimethylamine-N-oxide (TMAO), a choline-derived gut microbiota-dependent metabolite, is a newly recognized risk marker for cardiovascular disease. We sought to determine: (1) TMAO response to meals containing free versus lipid-soluble choline and (2) effects of gut microbiome on TMAO response. Methods: In a randomized, controlled, double-blinded, crossover study, healthy men (n = 37) were provided meals containing 600 mg choline either as choline bitartrate or phosphatidylcholine, or no choline control. Results: Choline bitartrate yielded three-times greater plasma TMAO AUC (p = 0.01) and 2.5-times greater urinary TMAO change from baseline (p = 0.01) compared to no choline and phosphatidylcholine. Gut microbiota composition differed (permutational multivariate analysis of variance, PERMANOVA; p = 0.01) between high-TMAO producers (with ≥40% increase in urinary TMAO response to choline bitartrate) and low-TMAO producers (with \u3c40% increase in TMAO response). High-TMAO producers had more abundant lineages of Clostridium from Ruminococcaceae and Lachnospiraceae compared to low-TMAO producers (analysis of composition of microbiomes, ANCOM; p \u3c 0.05). Conclusion: Given that phosphatidylcholine is the major form of choline in food, the absence of TMAO elevation with phosphatidylcholine counters arguments that phosphatidylcholine should be avoided due to TMAO-producing characteristics. Further, development of individualized dietary recommendations based on the gut microbiome may be effective in reducing disease risk

Prenatal Nutritional Intervention Reduces Autistic-Like Behavior Rates Among Mthfr-Deficient Mice

The causes and contributing factors of autism spectrum disorders (ASD) are poorly understood. One gene associated with increased risk for ASD is methylenetetrahydrofolate-reductase (MTHFR), which encodes a key enzyme in one carbon (C1) metabolism. The MTHFR 677C > T polymorphism reduces the efficiency of methyl group production with possible adverse downstream effects on gene expression. In this study, the effects of prenatal and/or postnatal diets enriched in C1 nutrients on ASD-like behavior were evaluated in Mthfr-deficient mice. Differences in intermediate pathways between the mice with and without ASD-like behaviors were tested. The findings indicate that maternal and offspring Mthfr deficiency increased the risk for an ASD-like phenotype in the offspring. The risk of ASD-like behavior was reduced in Mthfr-deficient mice supplemented with C1 nutrients prenatally. Specifically, among offspring of Mthfr+/- dams, prenatal diet supplementation was protective against ASD-like symptomatic behavior compared to the control diet with an odds ratio of 0.18 (CI:0.035, 0.970). Changes in major C1 metabolites, such as the ratios between betaine/choline and SAM/SAH in the cerebral-cortex, were associated with ASD-like behavior. Symptomatic mice presenting ASD-like behavior showed decreased levels of GABA pathway proteins such as GAD65/67 and VGAT and altered ratios of the glutamate receptor subunits GluR1/GluR2 in males and NR2A/NR2B in females. The altered ratios, in turn, favor receptor subunits with higher sensitivity to neuronal activity. Our study suggests that MTHFR deficiency can increase the risk of ASD-like behavior in mice and that prenatal dietary intervention focused on MTHFR genotypes can reduce the risk of ASD-like behavior

Increased homocysteine levels impair reference memory and reducecortical levels of acetylcholine in a mouse model of vascular cognitive impairment

Folates are B-vitamins that are vital for normal brain function. Deficiencies in folates either genetic(methylenetetrahydrofolate reductase, MTHFR) or dietary intake of folic acid result in elevated levelsof homocysteine. Clinical studies have shown that elevated levels of homocysteine (Hcy) may be associ-ated with the development of dementia, however this link remains unclear. The purpose of this study wasto evaluate the impact of increased Hcy levels on a mouse model of vascular cognitive impairment (VCI)produced by chronic hypoperfusion. Male and female Mthfr+/+and Mthfr+/−mice were placed on eithercontrol (CD) or folic acid deficient (FADD) diets after which all animals underwent microcoil implantationaround each common carotid artery or a sham procedure. Post-operatively animals were tested on theMorris water maze (MWM), y-maze, and rotarod. Animals had no motor impairments on the rotarod,y-maze, and could learn the location of the platform on the MWM. However, on day 8 of testing of MWMtesting during the probe trial, Mthfr+/−FADD microcoil mice spent significantly less time in the targetquadrant when compared to Mthfr+/−CD sham mice, suggesting impaired reference memory. All FADDmice had elevated levels of plasma homocysteine. MRI analysis revealed arterial remodeling was present in Mthfr+/− microcoil mice not Mthfr+/+ mice. Acetylcholine and related metabolites were reduced in cortical tissue because of microcoil implantation and elevated levels of homocysteine. Deficiencies in folate metabolism resulting in increased Hcy levels yield a metabolic profile that increases susceptibility to neurodegeneration in a mouse model of VCI

Choline Supplementation Normalizes Fetal Adiposity and Reduces Lipogenic Gene Expression in a Mouse Model of Maternal Obesity

Maternal obesity increases fetal adiposity which may adversely affect metabolic health of the offspring. Choline regulates lipid metabolism and thus may influence adiposity. This study investigates the effect of maternal choline supplementation on fetal adiposity in a mouse model of maternal obesity. C57BL/6J mice were fed either a high-fat (HF) diet or a control (NF) diet and received either 25 mM choline supplemented (CS) or control untreated (CO) drinking water for 6 weeks before timed-mating and throughout gestation. At embryonic day 17.5, HF feeding led to higher (p \u3c 0.05) percent total body fat in fetuses from the HFCO group, while the choline supplemented HFCS group did not show significant difference versus the NFCO group. Similarly, HF feeding led to higher (p \u3c 0.05) hepatic triglyceride accumulation in the HFCO but not the HFCS fetuses. mRNA levels of lipogenic genes such as Acc1, Fads1, and Elovl5, as well as the transcription factor Srebp1c that favors lipogenesis were downregulated (p \u3c 0.05) by maternal choline supplementation in the HFCS group, which may serve as a mechanism to reduce fat accumulation in the fetal liver during maternal HF feeding. In summary, maternal choline supplementation improves indices of fetal adiposity in obese dams at late gestation

Population genomics of marine zooplankton

Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here for personal use, not for redistribution. The definitive version was published in Bucklin, Ann et al. "Population Genomics of Marine Zooplankton." Population Genomics: Marine Organisms. Ed. Om P. Rajora and Marjorie Oleksiak. Springer, 2018. doi:10.1007/13836_2017_9.The exceptionally large population size and cosmopolitan biogeographic distribution that distinguish many – but not all – marine zooplankton species generate similarly exceptional patterns of population genetic and genomic diversity and structure. The phylogenetic diversity of zooplankton has slowed the application of population genomic approaches, due to lack of genomic resources for closelyrelated species and diversity of genomic architecture, including highly-replicated genomes of many crustaceans. Use of numerous genomic markers, especially single nucleotide polymorphisms (SNPs), is transforming our ability to analyze population genetics and connectivity of marine zooplankton, and providing new understanding and different answers than earlier analyses, which typically used mitochondrial DNA and microsatellite markers. Population genomic approaches have confirmed that, despite high dispersal potential, many zooplankton species exhibit genetic structuring among geographic populations, especially at large ocean-basin scales, and have revealed patterns and pathways of population connectivity that do not always track ocean circulation. Genomic and transcriptomic resources are critically needed to allow further examination of micro-evolution and local adaptation, including identification of genes that show evidence of selection. These new tools will also enable further examination of the significance of small-scale genetic heterogeneity of marine zooplankton, to discriminate genetic “noise” in large and patchy populations from local adaptation to environmental conditions and change.Support was provided by the US National Science Foundation to AB and RJO (PLR-1044982) and to RJO (MCB-1613856); support to IS and MC was provided by Nord University (Norway)