Metabonomic Profiling of Human Placentas Reveals Different Metabolic Patterns among Subtypes of Neural Tube Defects

Neural tube defects (NTDs) are one of the most common types of birth defects with a complex etiology. We have previously profiled serum metabolites of pregnant women in Lvliang prefecture, Shanxi Province of China, which revealed distinct metabolic changes in pregnant women with NTDs outcome. Here we present a metabonomics study of human placentas of 144 pregnant women with normal pregnancy outcome and 115 pregnant women affected with NTDs recruited from four rural counties (Pingding, Xiyang, Taigu, and Zezhou) of Shanxi Province, the area with the highest prevalence worldwide. A panel of 19 metabolites related to one-carbon metabolism was also quantitatively determined. We observed obvious differences in global metabolic profiles and one-carbon metabolism among three subtypes of NTDs, anencephaly (Ane), spina bifida (SB), and Ane complicated with SB (Ane & SB) via mass-spectrometry-based metabonomics approach. Disturbed carbohydrate, amino acid, lipid, and nucleic acid metabolism were identified. Placental transport of amino acids might be depressed in Ane and Ane & SB group. Deficiency of choline contributes to Ane and Ane & SB pathogenesis via different metabolic pathways. The formation of NTDs seemed to be weakly related to folates. The metabonomic analysis reveals that the physiological and biochemical processes of the three subtypes of NTDs might be different and the subtype condition should be considered for the future investigation of NTDs.