Identification Of Urine Metabolic Biomarkers For Vogt-koyanagi-harada Disease

Objective:The diagnosis of Vogt-Koyanagi-Harada(VKH)disease is mainly based on a complex clinical manifestation while it lacks objective laboratory biomarkers.To explore potential molecular biomarkers for diagnosis and disease activity in VKH,we performed untargeted urinary metabolomics analysis using ultra-high-performance liquid chromatography equipped with quadrupole time-of-flight mass spectrometry(UPLC-QTOF/MS).Methods: According to the inclusion criteria,UPLC-QTOF/MS was used to analyze the metabolomics of the urine of 26 patients with Vogt-Koyanagi-Haradadisease(15 active patients and 11 inactive patients)and 26 normal controls.Univariate and multivariate statistics were used to analyze the pattern recognition of different metabolites and to observe the differences between the two groups.Differential metabolites were screened and bioinformatics analysis was carried out to find the differential metabolic pathway.Finally,candidate marker metabolites with high specificity and sensitivity were screened by Logistic regression.Results: To explore the potential molecular biomarkers for diagnosis and disease activity in VKH,we performed an untargeted urine metabolomics analysis by UHPLC-Q-TOF/MS.Through univariate and multivariate statistical analysis,we found 9 differential metabolites when comparing VKH patients with healthy controls,and 26 differential metabolites were identified when comparing active VKH patients with inactive VKH patients.Pathway enrichment analysis showed that glycine,serine and threonine metabolism,and arginine and proline metabolism were significantly altered in VKH versus healthy controls.Lysine degradation and biotin metabolism pathways were significantly altered in active VKH versus inactive VKH.Furthermore,the receiver operating characteristic(ROC)curve analysis revealed that the combination of acetylglycine and gamma-glutamylalanine could differentiate VKH from healthy controls with an area under the curve(AUC)of 0.808.A combination of ureidopropionic acid and 5’-phosphoribosyl-5-amino-4-imidazolecarboxamide(AICAR)had an excellent AUC of 0.958 for distinguishing active VKH from inactive VKH.Conclusion:In summary,this study identified abnormal metabolites in urine of patients with VKH disease.Urine metabolomics is a feasible method to explore biomarkers for VKH syndrome and to distinguish disease activity.Further studies are needed to confifirm whether these metabolites are specifific for this disease.The current study shows that the application of urine metabolite analysis may serve as an auxiliary diagnostic tool and be helpful for the study of the pathophysiological mechanisms involved in the development of VKH disease.