Impact of infant protein supply and other early life factors on plasma metabolome at 5.5 and 8 years of age: a randomized trial.

OBJECTIVES: A high dairy protein intake in infancy, maternal pre-pregnancy BMI, and delivery mode are documented early programming factors that modulate the later risk of obesity and other health outcomes, but the mechanisms of action are not understood. METHODS: The Childhood Obesity Project is a European multicenter, double-blind, randomized clinical trial that enrolled healthy infants. Participating infants were either breastfed (BF) or randomized to receive higher (HP) or lower protein (LP) content formula in the first year of life. At the ages 5.5 years (n = 276) and 8 years (n = 232), we determined plasma metabolites by liquid chromatography tandem-mass-spectrometry of which 226 and 185 passed quality control at 5.5 years and 8 years, respectively. We assessed the effects of infant feeding, maternal pre-pregnancy BMI, smoking in pregnancy, delivery mode, parity, birth weight and length, and weight gain (0-24 months) on the metabolome at 5.5 and 8 years. RESULTS: At 5.5 years, plasma alpha-ketoglutarate and the acylcarnitine/BCAA ratios tended to be higher in the HP than in the LP group, but no metabolite reached statistical significance (Pbonferroni>0.09). There were no group differences at 8 years. Quantification of the impact of early programming factors revealed that the intervention group explained 0.6% of metabolome variance at both time points. Except for country of residence that explained 16% and 12% at 5.5 years and 8 years, respectively, none of the other factors explained considerably more variance than expected by chance. CONCLUSIONS: Plasma metabolome was largely unaffected by feeding choice and other early programming factors and we could not prove the existence of a long term programming effect of the plasma metabolome.

Are All Breast-fed Infants Equal? Clustering Metabolomics Data to Identify Predictive Risk Clusters for Childhood Obesity.

OBJECTIVES: Fetal and early life represent a period of developmental plasticity during which metabolic pathways are modified by environmental and nutritional cues. Little is known on the pathways underlying this multifactorial complex. We explored whether 6 months old breast-fed infants could be clustered into metabolically similar groups and that those metabotypes could be used to predict later obesity risk. METHODS: Plasma samples were obtained from 183 breast-fed infants aged 6 months participating in the European multicenter Childhood Obesity Project study. We measured amino acids along with polar lipid concentrations (acylcarnitines, lysophosphatidylcholines, phosphatidylcholines, sphingomyelins). We determined the metabotypes using a Bayesian agglomerative clustering method and investigated the properties of these clusters with respect to clinical, programming, and metabolic factors up to 6 years of age. RESULTS: We identified 20 metabolite clusters comprising 1 to 39 children. Phosphatidylcholines predominantly influenced the clustering process. In the largest clusters (n ≥ 14), large differences existed for birth length (unadjusted P < 0.0001) and length and weight at 6 months (unadjusted P < 0.0001 and P = 0.012, respectively). Infants tended to cluster together by country (unadjusted P < 0.001). The body mass index (BMI) z score at 6 years of age tended to differ (unadjusted P = 0.07). CONCLUSIONS: Our exploratory study provided evidence that breast-fed infants are not metabolically homogeneous and that variation in metabolic profiles among infants may provide insight into later development and health. This work highlights the potential of metabotypes for identifying inter-individual differences that may form the basis for developing personalized early preventive strategies.

Metabolomics reveals an entanglement of fasting leptin concentrations with fatty acid oxidation and gluconeogenesis in healthy children.

BACKGROUND: Leptin and adiponectin communicate with organ systems in order to regulate energetic and metabolic homeostasis. Their different points of action have been well characterized; however, no study has investigated their interrelationship with the metabolism at the molecular level in vivo. OBJECTIVE: To examine the associations of leptin and adiponectin with the metabolic profile reflecting the intercellular and interorgan communication as well as activated metabolic pathways. PATIENTS/METHODS: We measured plasma concentrations of leptin, adiponectin, and insulin along with concentrations of 196 metabolites in 400 healthy, fasting 8-years old German children who participated in the German Ulm Birth Cohort Study (UBCS). Using multiple linear mixed models, we evaluated the associations between hormones and metabolites. RESULTS: Leptin levels increased exponentially with increasing BMI. Leptin was furthermore strongly associated with alanine and aspartate (Bonferroni corrected P[PBF] = 5.7×10-8 and 1.7×10-6, respectively), and negatively associated to the sum of the non-esterified fatty acids (NEFA) and the sum of the long-chain acylcarnitines C12-C18 (PBF = 0.009 and 0.0001, respectively). Insulin showed a similar association pattern, although the associations were less strong than for leptin. Adiponectin was neither related to BMI nor to any metabolite. CONCLUSION: Although children were presumably metabolically similar, we found strong associations of insulin and leptin with the metabolite profile. High alanine concentrations and the lower concentrations of NEFA in children with high fasting leptin concentrations might arise from an increased gluconeogenesis and from the disinhibiting effect of leptin on the carnitine-palmitoyltransferase-1, respectively. As insulin had the same trend towards these associations, both hormones seem to be related to processes that provide the body with energy in fasting state.

Tyrosine Is Associated with Insulin Resistance in Longitudinal Metabolomic Profiling of Obese Children.

In obese children, hyperinsulinaemia induces adverse metabolic consequences related to the risk of cardiovascular and other disorders. Branched-chain amino acids (BCAA) and acylcarnitines (Carn), involved in amino acid (AA) degradation, were linked to obesity-associated insulin resistance, but these associations yet have not been studied longitudinally in obese children. We studied 80 obese children before and after a one-year lifestyle intervention programme inducing substantial weight loss >0.5 BMI standard deviation scores in 40 children and no weight loss in another 40 children. At baseline and after the 1-year intervention, we assessed insulin resistance (HOMA index), fasting glucose, HbA1c, 2 h glucose in an oral glucose tolerance test, AA, and Carn. BMI adjusted metabolite levels were associated with clinical markers at baseline and after intervention, and changes with the intervention period were evaluated. Only tyrosine was significantly associated with HOMA (p < 0.05) at baseline and end and with change during the intervention (p < 0.05). In contrast, ratios depicting BCAA metabolism were negatively associated with HOMA at baseline (p < 0.05), but not in the longitudinal profiling. Stratified analysis revealed that the children with substantial weight loss drove this association. We conclude that tyrosine alterations in association with insulin resistance precede alteration in BCAA metabolism. This trial is registered with ClinicalTrials.gov Identifier NCT00435734.