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.

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.

Placental MFSD2a transporter is related to decreased DHA in cord blood of women with treated gestational diabetes.

Background & Aims: Maternal-fetal transfer of docosahexaenoic acid (DHA) is impaired by gestational diabetes mellitus (GDM), but the underlying mechanisms are still unknown. MFSD2a was recently recognized as a lyso-phospholipid (lyso-PL) transporter that facilitates DHA accretion in brain. The role of this transporter in placenta is uncertain.

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.

Three-month B vitamin supplementation in pre-school children affects folate status and homocysteine, but not cognitive performance.

Background: Suboptimal vitamin B status might affect cognitive performance in early childhood. We tested the hypothesis that short-term supplementation with folic acid and selected B vitamins improves cognitive function in healthy children in a population with relatively low folate status.

Methods: We screened 1,002 kindergarten children for suboptimal folate status by assessing the total urinary para-aminobenzoylglutamate excretion.

Association between plasma nonesterified fatty acids species and adipose tissue fatty acid composition.

Fatty acid composition of adipose tissue (AT) is an established long-term biomarker for fatty acid (FA) intake and status, but AT samples are not easily available. Nonesterified FA composition in plasma (pNEFA) may be a good indicator of AT FA composition, because pNEFA are mainly generated by AT lipolysis. We investigated the correlation of 42 pNEFA and subcutaneous as well as visceral AT FA in 27 non-diabetic women with a median BMI of 36 kg/m(2) (Q0.

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.

Folate catabolites in spot urine as non-invasive biomarkers of folate status during habitual intake and folic acid supplementation.

Background: Folate status, as reflected by red blood cell (RCF) and plasma folates (PF), is related to health and disease risk. Folate degradation products para-aminobenzoylglutamate (pABG) and para-acetamidobenzoylglutamate (apABG) in 24 hour urine have recently been shown to correlate with blood folate.

Aim: Since blood sampling and collection of 24 hour urine are cumbersome, we investigated whether the determination of urinary folate catabolites in fasted spot urine is a suitable non-invasive biomarker for folate status in subjects before and during folic acid supplementation.

Determination of creatinine in human urine with flow injection tandem mass spectrometry.

Background/aims: Excretion of urinary compounds in spot urine is often estimated relative to creatinine. For the growing number of liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays of urine-excreted molecules, a fast and accurate method for determination of creatinine is needed.

Methods: A high-throughput flow injection tandem mass spectrometry method for exact quantitation of creatinine in urine has been developed and validated.

Nonesterified fatty acid determination for functional lipidomics: comprehensive ultrahigh performance liquid chromatography-tandem mass spectrometry quantitation, qualification, and parameter prediction.

Despite their central importance for lipid metabolism, straightforward quantitative methods for determination of nonesterified fatty acid (NEFA) species are still missing. The protocol presented here provides unbiased quantitation of plasma NEFA species by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Simple deproteination of plasma in organic solvent solution yields high accuracy, including both the unbound and initially protein-bound fractions, while avoiding interferences from hydrolysis of esterified fatty acids from other lipid classes.

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.

Aqueous normal phase chromatography improves quantification and qualification of homocysteine, cysteine and methionine by liquid chromatography-tandem mass spectrometry.

Elevation of plasma homocysteine concentration is recognized as an independent predictor of cardiovascular disease risk. Therefore, quantification of homocysteine and related sulphur amino acids cysteine and methionine from plasma samples is routinely performed in clinical laboratories. Due to the highly hydrophilic character of these amino acids, previously reported LC-MS methods often suffered from very short chromatographic retention resulting in inadequate separation from matrix background and possible co-eluents.