Published online Aug 14, 2018. doi: 10.3748/wjg.v24.i30.3448
Peer-review started: May 4, 2018
First decision: May 23, 2018
Revised: June 8, 2018
Accepted: June 25, 2018
Article in press: June 25, 2018
Published online: August 14, 2018
Chronic hepatitis B is a major infectious disease in China and Chinese medicine has a wide range of applications in the treatment of CHB. Tongue diagnosis has important guiding significance for clinical syndrome differentiation and drug use in TCM, but lacks scientific explanations. Some reports have found abnormalities in the microbiota or metabolites in pathological tongue coatings. However, integrated analyses of the pathological tongue coating microbiotas and metabolites have rarely been reported. Elucidating the tongue coatings micro-features differences will promote our understanding of the TCM tongue diagnosis and facilitate therapeutic strategies for individualized treatment.
The motivation of this study was to explore the microfeatures of different tongue coatings, which could promote our understanding of the TCM tongue diagnosis from a modern perspective.
The objective of this research was to elucidate tongue coating microbiota and metabolic differences in CHB patients with yellow or white tongue coatings.
We collected tongue coating samples from 28 CHB yellow tongue coating patients and 25 CHB white tongue coating patients, and an additional 22 samples were collected from healthy controls. The tongue coating bacterial 16S ribosomal RNA gene V3 region was amplified and sequenced with the Ion Torrent PGM™ sequencing platform. The metabolites in the tongue coatings were examined using a LC-MS platform. The microbiota results were analyzed using Metastats analysis, the Kruskal-Wallis test and LEfSe analysis. The functionality of the microbiota was assessed using PiCRUST and compared among groups. The metabolomics enrichment analysis was performed with MetaboAnalyst 3.0 (http://www.metaboanalyst.ca). We correlated the microbiota with the clinical indices and metabolites and visualized the results with Spearman’s correlation coefficients > 0.3 and P < 0.05 in Cytoscape.
This study found taxonomic and predicted function differences between the CHB yellow and white tongue coating patients. Distinct from those of the white coating patients, the CHB yellow tongue coating patients had specific clinical and microbiota characteristics. The microbiota of the CHB patients with yellow tongue coatings had similarities with a gut disorder in patients with cirrhosis at the phylum level, which manifested as a reduced abundance of Bacteroidetes and increased Proteobacteria content. Neisseriaceae, which is a dominant bacterial family enriched in yellow tongue coating patients, was positively correlated with the serum HBV-DNA level. The inferred metagenomic pathways enriched in the CHB yellow tongue coating patients were mainly those involved in amino acid metabolism, whereas the detected metabolites were mainly essential amino acids and generally were present in larger amounts than in the white tongue coatings.
We found that the yellow and white tongue coatings of CHB patients had microbiota compositional and functional differences in this study.
The sample size in this study was small. In the future, we will expand the sample size to further verify the results and focus on the relationship between changes in the oral and intestinal microbiotas to explore the effects of oral microbiota variance on immunity and metabolic alterations in the body. These studies will further explain the modern theoretical mechanism of TCM tongue diagnosis.