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.

Dietary protein intake affects amino acid and acylcarnitine metabolism in infants aged 6 months.

Context: The protective effect of breast-feeding against later obesity may be explained by the lower protein content compared with formula milk. However, the metabolic mechanisms remain unknown.

Objective: We studied the metabolic response to a higher or lower protein supply in infancy.

Rapid growth and childhood obesity are strongly associated with lysoPC(14:0).

Background: Despite the growing interest in the early-origins-of-later-disease hypothesis, little is known about the metabolic underpinnings linking infant weight gain and childhood obesity.

Objective: To discover biomarkers reflective of weight change in the first 6 months and overweight/obesity at age 6 years via a targeted metabolomics approach.

Design: This analysis comprised 726 infants from a European multicenter randomized trial (Childhood Obesity Programme, CHOP) for whom plasma blood samples at age 6 months and anthropometric data up to the age of 6 years were available.

Changes in the serum metabolite profile in obese children with weight loss.

Purpose: Childhood obesity is an increasing problem and is accompanied by metabolic disturbances. Recently, we have identified 14 serum metabolites by a metabolomics approach (FIA-MS/MS), which showed altered concentrations in obese children as compared to normal-weight children. Obese children demonstrated higher concentrations of two acylcarnitines and lower levels of three amino acids, six acyl-alkyl phosphatidylcholines, and three lysophosphatidylcholines.

Quantification of urinary folate catabolites using liquid chromatography-tandem mass spectrometry.

Folate catabolites p-aminobenzoylglutamate (pABG) and p-acetamidobenzoylglutamate (apABG) in human urine result from break-down of endogenous folate pools and are potential biomarkers of folate status. There is growing interest in analysis of these non-invasive indicators of folate status, since widespread diseases such as cancer, arteriosclerosis and dementia may be linked to disturbed availability of folates. Determination of pABG and apABG in human urine is challenging due to their low urinary concentrations and due to interferences with other urinary compounds.

Quantification of 22 plasma amino acids combining derivatization and ion-pair LC-MS/MS.

Time efficient and comprehensive quantification of amino acids continues to be a challenge. We developed a sensitive and precise method for quantitative analysis of amino acids from very small plasma and serum volumes. Ion-pair chromatography of amino acid butyl esters proved to provide an optimal combination of selectivity, sensitivity and robustness.