Metabolomic Markers in Tongue-Coating Samples from Damp Phlegm Pattern Patients of Coronary Heart Disease and Chronic Renal Failure.

In this paper, we used tongue coating to obtain metabolites in patients with coronary heart disease (CHD) and chronic renal failure (CRF). The metabolites were analyzed to discover the substance that serves as the underlying basis of the damp phlegm pattern. This analysis is based on the Traditional Chinese Medicine (TCM) theory of "different diseases have the same pattern." The metabolic spectrum was obtained through the Gas Chromatography Mass Spectrometry coupling techniques and analyzed by searching the METLIN and HMDB databases. Some metabolites related to amino acids and glucose metabolism were identified in the tongue-coating samples from damp phlegm pattern patients by comparing them to nondamp phlegm pattern patients and healthy subjects. In addition, there were five common metabolites in the tongue-coating samples from CHD damp phlegm pattern patients compared to CRF damp phlegm pattern patients, which allowed us to understand the theory of "different diseases have the same pattern." In the future, the metabolites identified in this study may be used as noninvasive and convenient biomarkers to distinguish the damp phlegm pattern of CHD and CRF patients.