Presented at the Neonatal Society 2015 Autumn Meeting.
Andreas NJ1, Hyde MJ1, Jeffries S1, Holmes E2, Modi N1
1 Section of Neonatal Medicine, Department of Medicine, Imperial College London, UK
2 Section of Computational and Systems Medicine, Faculty of Medicine, Imperial College London, UK
Background: Metabolic profiling of urine provides a unique insight into the current metabolic state of an individual. Metabonomic studies have suggested that an individual’s Body Mass Index (BMI) influences the urinary metabolome (1). We sought to further study the relationship between BMI and the urinary metabolome in mothers and infants over the first three months post-partum. We tested the hypothesis that we would observe differences in the urinary metabolome of mother and infant samples from high and normal BMI mothers.
Methods: We recruited mothers who delivered at term on the post-natal ward at Chelsea and Westminster Hospital. Mothers and infants donated samples on the post-natal ward, at seven days and three months post-partum. 84 mothers had a booking BMI <25, and 22 had a BMI >25. Samples were analysed using 1H NMR spectroscopy. We used PCA and OPLS to assess the relationship between the infant and maternal metabolome and maternal BMI. The study received Research Ethics approval (12/LO/0203) and was funded by Westminster Medical School Research Trust.
Results: We obtained a total of 527 samples (Recruitment mother/infant=107/47, one week=103/82, 3 months=97/91). The average BMI of the mothers decreased from 26 to 23.9 kg/m2 from recruitment to 3 months post-partum. We found no statistically significant association between maternal BMI and the infant urinary metabolome at any time point. Formula feeding did however appear to influence the infant urinary metabolome, with higher concentrations of phenylacetylglutamine and 3-aminoisbutyrate observed in breastfed infants. Maternal urine samples separated in the PCA scores plot between the time points, predominantly due to the reduction in medications being taken at 3 months post-partum. At the recruitment and 7 day time points, no differences were detected in the maternal urinary metabolome based on maternal BMI, but at three months post-partum, the concentrations of creatine, creatinine and trimethylamine-N-oxide were increased in mothers possessing a higher BMI, whilst hippuric acid concentrations were decreased.
Conclusion: Metabolites altering in concentration in the maternal urinary metabolome in regard to BMI are associated with the co-metabolism between human and the intestinal microbiota, in agreement with previous studies. No such association was observed in the infant samples, however, similarly co-metabolites with the microbiota were altered as a result of formula feeding infants. The consequences of having an altered microbiota are unknown but an area of future research.
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1. Elliott P, Posma JM, Chan Q, Garcia-Perez I, Wijeyesekera A, Bictash M, et al. Urinary metabolic signatures of human adiposity. Sci Transl Med. 2015;7(285):285ra62.