Identification of salivary and plasma biomarkers for obesity in children by non-targeted metabolomic analysis

Abstract

Chemical compounds in the saliva most likely to be associated with obesity are identified in a metabolomic analysis of paired whole saliva and plasma samples from 68 children (10-year old) who have also been evaluated for their gingival redness.Results: Through metabolomic analysis119 compounds were found only in saliva, 210 only in plasma and 126 in both. The most common plasma metabolites were lipids. The most common saliva metabolites were peptides. Amino acids and their metabolites were common in both samples.Surrogate indicators were identified by computing correlations between saliva and plasma. 29 of the 126 found in both saliva and plasma had significant positive correlation and only 4 of those (urate, creatinine, pipecolate and hydroxyproline) were associated with obesity as potential surrogate biomarkers. The uremic toxin N1-Methyl-2-pyridone-5-carboxamide (2PY) was also elevated in the saliva of obese children. 21 biochemicals were elevated in both obesity and gingivitis suggesting that some biochemical pathways for gingivitis and obesity are shared.Of the metabolites found only in saliva, 35 were associated with obesity (p<0.01). The most significant was phosphate. Saliva had 53 dipeptides, seven of which were associated with obesity. Two volatile amines (putrescine and cadaverine) and their amino acid precursors (ornithine and lysine) were also associated with obesity.Of the metabolites found only in plasma, 64 were associated with obesity (p<0.01).Significant increases in branched-chain and aromatic amino acids, significant reductions in serotonin, serine, and glycine and increased androgen metabolism are changes observed in 10-year old obese children that have also been reported with adult patients having type II diabetes.

Relationships between Gut Microbiota, Metabolome, Body Weight, and Glucose Homeostasis of Obese Dogs Fed with Diets Differing in Prebiotic and Protein Content

“…Identification of diaminoheptanedioate, a molecule in the cell wall of Gram-negative bacteria, as a discriminant metabolite found in the metavariable PlasmaLD2 suggested that obesity and its associated metabolic disorders are correlated to a high LPS level. Furthermore, hydroxyproline, a possible stress marker but also an obesity marker [59], was also a discriminant metabolite in our metavariable PlasmaLD2, while our metavariable GenusD1 including Escherichia-Shigella was positively correlated with blood haptoglobin, another inflammatory marker. These findings support the recent results obtained by Jergens et al (2019;[10]) using both type 2 diabetes mellitus dogs and healthy dogs.…”