Tongue coating metabolic profiles of intra-oral halitosis patients.

OBJECTIVE: This study focused on the metabolic characteristics of tongue coating in patients with intra-oral halitosis (IOH) to investigate potential diagnostic biomarkers for IOH. METHODS: Oral healthy participants were enrolled in this study. Halitosis was evaluated with an organoleptic assessment, a Halimeter®, and an OralChroma™. Tongue coating samples were collected from 18 halitosis patients and 18 healthy controls. Liquid chromatography-mass spectrometry was conducted to reveal the IOH-related metabolic variations in tongue coating. RESULTS: A total of 2214 metabolites were obtained. Most metabolites were shared between the two groups. A total of 274 upregulated metabolites, such as paramethasone acetate and indole-3-acetic acid, and 43 downregulated metabolites, including deoxyadenosine and valyl-arginine, were detected in the halitosis group. Functional analysis indicated that several metabolic pathways, including arginine biosynthesis, arginine and proline metabolism, histidine metabolism, and lysine degradation were significantly enriched in the IOH group. The least absolute shrinkage and selection operator logistic regression analysis revealed that paramethasone acetate, {1-[2-(4-carbamimidoyl-benzoylamino)-propionyl]-piperidin-4-yloxy}-acetic acid, indole-3-acetic acid, and valyl-arginine were remarkably associated with IOH. CONCLUSIONS: This study revealed the metabolites present in tongue coating and identified effective biomarkers, providing essential insights into the prediction, pathogenesis, and diagnosis of IOH.

[Metabolomics study on the difference of tongue coating metabolites between patients with intra-oral halitosis and healthy individual].

PURPOSE: To analyze the difference of metabolites of tongue coating between patients with intra-oral halitosis and healthy individuals by untargeted metabolomics, and to explore significant differences in metabolites of intra-oral halitosis as biomarkers. METHODS: The untargeted metabolomics of tongue coating samples from 12 patients with intra-oral halitosis and 12 healthy individuals were studied by liquid chromatography and mass spectrometry combined with principal component analysis and orthogonal partial least squares discriminant analysis. The value of variable importance in projection ＞1 and P＜0.05 of Student's t test in the orthogonal partial least squares-discriminant analysis model were used as the criteria to screen and determine the differential metabolites. RESULTS: There were differences in the metabolites of tongue coating between patients with intra-oral halitosis and healthy individuals, and 11 different metabolites were identified. They were valyl-arginine, glycine-phenylalanine, tryptophyl-proline, deoxyadenosine, 4,5-dihydroniveusin A, N-acetyl-DL-tryptophan, paramethasone acetate, cyclopentanol, [(2-hexylcyclopentylidene) amino]thiourea, L-pipecolic acid and taurine. In the intra-oral halitosis group, the expressions of Glycine-phenylalanine and N-acetyl-DL-tryptophan were significantly up-regulated, while the expressions of taurine were significantly down-regulated. CONCLUSIONS: There are differences in the metabolites of tongue coating between patients with intra-oral halitosis and healthy individuals. The differential metabolites with diagnostic value may be used as diagnostic markers of intra-oral halitosis.