Infant Metabolome in Relation to Prenatal DHA Supplementation and Maternal Single-Nucleotide Polymorphism rs174602: Secondary Analysis of a Randomized Controlled Trial in Mexico

Abstract

Background: Although DHA (22:6n-3) is critical for fetal development, results from randomized controlled trials (RCTs) of prenatal DHA supplementation report inconsistent effects on offspring health. Variants in fatty acid desaturase (FADS) genes that regulate the conversion of n-3 and n-6 essential fatty acids into their biologically active derivatives may explain this heterogeneity.

Objectives: We investigated the effect of prenatal DHA supplementation on the offspring metabolome at age 3 mo and explored differences by maternal FADS single-nucleotide polymorphism (SNP) rs174602.

Methods: Data were obtained from a double-blind RCT in Mexico [POSGRAD (Prenatal Omega-3 Fatty Acid Supplementation and Child Growth and Development)] in which women (18-35 y old) received DHA (400 mg/d) or placebo from mid-gestation until delivery. Using high-resolution MS with LC, untargeted metabolomics was performed on 112 offspring plasma samples. Discriminatory metabolic features were selected via linear regression (P < 0.05) with false discovery rate (FDR) correction (q = 0.2). Interaction by SNP rs174602 was assessed using 2-factor ANOVA. Stratified analyses were performed, where the study population was grouped into carriers (TT, TC; n = 70) and noncarriers (CC; n = 42) of the minor allele. Pathway enrichment analysis was performed with Mummichog (P < 0.05).

Results: After FDR correction, there were no differences in metabolic features between infants whose mothers received prenatal DHA (n = 58) and those whose mothers received placebo (n = 54). However, we identified 343 differentially expressed features in the interaction analysis after FDR correction. DHA supplementation positively enriched amino acid and aminosugars metabolism pathways and decreased fatty acid metabolism pathways among offspring of minor allele carriers and decreased metabolites within the tricarboxylic acid cycle and galactose metabolism pathways among offspring of noncarriers.

Conclusions: Our findings demonstrate differences in infant metabolism in response to prenatal DHA supplementation by maternal SNP rs174602 and further support the need to incorporate genetic analysis of FADS polymorphisms into DHA supplementation trials.This trial was registered at clinicaltrials.gov as NCT00646360.

Keywords: DHA; FADS; Mexico; SNPs; prenatal supplementation; untargeted metabolomics.

© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society for Nutrition.

Figures

FIGURE 1

Flow of sample selection from the Prenatal Omega-3 Fatty Acid Supplementation and Child Growth and Development trial. SNP, single-nucleotide polymorphism.

FIGURE 2

Interaction between prenatal DHA supplementation and maternal SNP rs174602. (A) Manhattan plot as a function of m/z in interaction analysis (n = 112; P < 0.05: 1684 features; q < 0.2: 343 features). (B) Pathway enrichment analysis in Mummichog version 2.3.3 using input from metabolic features significantly associated with the interaction between treatment group and maternal SNP rs174602. The y axis represents differentially enriched pathways, whereas the x axis represents the negative log10P value of each pathway. The radii of data points correspond to the number of significantly associated metabolic features within the pathway. Only pathways with ≥4 overlapping metabolites are shown. (C) Boxplots comparing the intensity of select metabolic features within significantly enriched pathways between groups. The box portion of the plot represents the interquartile range (IQR: 25th percentile, median, and 75th percentile) of the data. Error bars represent smallest and largest values within 1.5 times IQR. 1Select metabolites from arginine and proline metabolism and aspartate and asparagine metabolism pathways. 2Select metabolite from carbon fixation pathway. 3Select metabolites from fatty acid metabolism pathway. C, carriers of minor allele for SNP rs174602; DHA, offspring whose mothers received prenatal DHA; HMDB, Human Metabolome Database; NC, noncarriers of minor allele for SNP rs174602; P, offspring whose mothers received placebo; rt, retention time; SNP, single-nucleotide polymorphism.

FIGURE 3

Stratified analysis by maternal fatty acid desaturase 2 single-nucleotide polymorphism rs174602. Manhattan plots as a function of m/z in (A) carriers (n = 70; P < 0.05: 615 features; q < 0.2: 1 feature) and (B) noncarriers (n = 42; P < 0.05: 666 features; q < 0.2: 1 feature).

FIGURE 4

Two-way hierarchical cluster analysis of treatment group (DHA compared with placebo) and (A) 279 discriminatory features selected via linear regression (P < 0.05) from the complete analytic sample (n = 112), (B) 615 features identified from carriers of the minor T allele (n = 70), and (C) 666 features identified from noncarriers of the minor T allele (n = 42). Each column represents an individual's metabolic profile based on differentially expressed features.

FIGURE 5

Pathway enrichment from stratified analysis by maternal fatty acid desaturase 2 single-nucleotide polymorphism rs174602. (A) Pathway enrichment analysis in Mummichog version 2.3.3 using input from metabolic features significantly associated with treatment group in the stratified analysis. The y axis represents differentially enriched pathways, whereas the x axis represents the negative log10P value of each pathway. The radii of data points correspond to the number of significantly associated metabolic features within the pathway. Only pathways with ≥4 overlapping metabolites are shown. (B, C) Boxplots comparing the intensity of select metabolic features within significantly enriched pathways between infants whose mothers received DHA or placebo in (B) carriers and (C) noncarriers. The box portion of the plot represents the interquartile range (IQR: 25th percentile, median, and 75th percentile) of the data. Error bars represent smallest and largest values within 1.5 times IQR. 1Select metabolites from arginine and proline metabolism and aspartate and asparagine metabolism pathways. 2Select metabolites from fatty acid metabolism and AA metabolism pathways. 3Select metabolites from TCA metabolism, galactose metabolism, and aminosugars metabolism pathways. AA, arachidonic acid; HMDB, Human Metabolome Database; LMFA, Lipid Maps Fatty Acyls; rt, retention time; TCA, tricarboxylic acid.