Serum metabolomic analysis of the effect of exercise on nonalcoholic fatty liver disease

Objective: Exercise benefits people with nonalcoholic fatty liver disease (NAFLD). The aim of this study was to identify a panel of biomarkers and to provide the possible mechanism for the effect of exercise on NAFLD patients via an untargeted mass spectrometry-based serum metabolomics study. Methods: NAFLD patients were classified randomly into a control group (n = 74) and a 6-month vigorous exercise (n = 68) group. Differences in serum metabolic profiles were analyzed using untargeted ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) technology. Principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) were used to validate the differences between these two groups, and altered metabolites were obtained by ANOVA (fold change >2, P < 0.05) and identified with the online database Metlin and an in-house database. Results: Metabolic profiling and multiple statistical analyses of the serum samples indicated significant differences between the NAFLD patients in the control and the 6-month vigorous exercise groups. Finally, 36 metabolites were identified between the control vs exercise groups. These metabolites were mainly associated with glycerophospholipid-and sphingolipid-related pathways. Conclusion: Our study demonstrates that glycerophospholipid and sphingolipid alterations may contribute to the mechanism underlying the effect of exercise on NAFLD patients. A LC-MS-based metabolomics approach has a potential value for screening exercise-induced biomarkers.