Influence of moderate maternal nutrition restriction on the fetal baboon metabolome at 0.5 and 0.9 gestation

BACKGROUND AND AIMS

Moderately reduced maternal nutrient availability during pregnancy has adverse effects on the fetuses' growth and metabolism during and after pregnancy. The aim of this study was to explore effects of maternal nutrition restriction (MNR) on key metabolites of the fetal energy metabolism, particularly amino acids (AA), nonesterified fatty acids (NEFA), acylcarnitines and phospholipids. These effects may reflect mechanisms relating MNR to later adverse outcomes.

METHODS AND RESULTS

Plasma and liver samples of fetal baboons, whose mothers were fed ad libitum (CTR) or MNR (70% of CTR), were collected at 0.5 and 0.9 gestation (G - term 184 days). Metabolites were measured with liquid chromatography coupled to mass spectrometry. In both, CTR and MNR, fetal metabolic profiles changed markedly between 0.5G and 0.9G. Fetal liver glucose concentrations were strongly increased. Hepatic levels of NEFA, sphingomyelins, and alkyl-linked phospholipids increased while plasma NEFA and acyl-linked phospholipids levels decreased with progression of gestation. At 0.5G, MNR fetal plasma levels of short- and medium-chain acylcarnitines were elevated, but did no longer differ between groups at 0.9G. At 0.9G, plasma levels of methionine and threonine as well as hepatic threonine levels were lower in the MNR group.

CONCLUSION

Small differences in the concentrations of plasma and liver metabolites between MNR and CTR fetuses reflect good adaptation to MNR. Fetal liver metabolic profiles changed markedly between the two gestation stages, reflecting enhanced liver glucose and lipid levels with advancing gestation. Decreased concentrations of AA suggest an up-regulation of gluconeogenesis in MNR.

Association of maternal prepregnancy BMI with metabolomic profile across gestation

BACKGROUND/OBJECTIVES

Elevated prepregnancy body mass index (pBMI) and excess gestational weight gain (GWG) constitute important prenatal exposures that may program adiposity and disease risk in offspring. The objective of this study is to investigate the influence of pBMI and GWG on the maternal metabolomic profile across pregnancy, and to identify associations with birth weight.

SUBJECTS/METHODS

This is a longitudinal prospective study of 167 nondiabetic women carrying a singleton pregnancy. Women were recruited between March 2011 and December 2013 from antenatal clinics affiliated to the University of California, Irvine, Medical Center. Seven women were excluded from analyses because of a diagnosis of diabetes during pregnancy. A total of 254 plasma metabolites known to be related to obesity in nonpregnant populations were analyzed in each trimester using targeted metabolomics. The effects of pBMI and GWG on metabolites were tested through linear regression and principle component analysis, adjusting for maternal sociodemographic factors, diet, and insulin resistance. A Bonferroni correction was applied for multiple comparison testing.

RESULTS

pBMI was significantly associated with 40 metabolites. Nonesterified fatty acids (NEFA) showed a strong positive association with pBMI, with specificity for mono-unsaturated and omega-6 NEFA. Among phospholipids, sphingomyelins with two double bonds and phosphatidylcholines containing 20:3 fatty acid chain, indicative of omega-6 NEFA, were positively associated with pBMI. Few associations between GWG, quality and quantity of the diet, insulin resistance and the maternal metabolome throughout gestation were detected. NEFA levels in the first and, to a lesser degree, in the second trimester were positively associated with birth weight percentiles.

CONCLUSIONS

Preconception obesity appears to have a stronger influence on the maternal metabolic milieu than gestational factors such as weight gain, dietary intake and insulin resistance, highlighting the critical importance of preconception health. NEFA in general, as well as monounsaturated and omega-6 fatty acid species in particular, represent key metabolites for a potential mechanism of intergenerational transfer of obesity risk.