Urine Metabolomic Characteristics Of Patients With Vitiligo And The Effect Of 17β-estradiol On Oxidative Stress In Melanocytes

BackgroundVitiligo is a common acquired pigmentary disorder.Till now,there have been no reliable well-known biomarkers for diagnosis,evaluation of disease progression,or treatment response in vitiligo.Urinary metabolomcs is a useful non-invasive tool for large-scale screening of disease-related metabolites.However,no comprehensive urinary metabolomic analysis of vitiligo is presently available.ObjectiveTo investigate the urine metabolic pattern of vitiligo patients,and to further explore the role the metabolites play in the occurrence and development of vitiligo.Methodwe conducted a combined cross-sectional and prospective self-control cohort study and an untargeted urinary metabolomic analysis.In the cross-sectional study,295 vitiligo patients and 192 age-and sex-matched controls were enrolled.In the self-control cohort,46 active vitiligo patients were recruited to analyse the urinary metabolic signatures after treatment.All of these patients were asked to undertake follow-up visits every 2 months three times after first consulting and the disease stage was evaluated compared with that at the last visit.The middle urine of all enrolled patients was collected for metabolomics analysis.Then key metabolic biomarkers screened were further validated through cell experiments in order to investigate their role in the development of vitiligo.Result1.In cross-sectional study,71 differential metabolites between two groups were identified.Pathway enrichment analysis revealed that drug metabolism-cytochrome P450,biopterin metabolism,vitamin B9(folate)metabolism,selenoamino acid metabolism,and methionine and cysteine metabolism showed significant enrichment in vitiligo patients compared with the status in healthy controls.A potential biomarker panel consisting 7alpha-hydroxy-3-oxochol-4-en-24-oic acid,deoxyuridine,3,4-octadienoylglycine and threoninyl-Proline was defined with an AUC of 0.783.2.In prospective self-control cohort study,folate metabolism,linoleate metabolism,leukotriene metabolism,alkaloid biosynthesis,and tyrosine metabolism were predicted to be involved in vitiligo activity.A panel consisting of 4-Methoxy-17beta-estradiol,dehydroepiandrosterone and cortexolone was used for treatment model with AUCs of 0.501,0.726 and 0.771 in first follow-up samples,second follow-up samples and third follow-up samples respectively.3.According to the results of urine metabolomics experiment,our study further studied the oxidative stress of melanocytes on the screened key metabolic marker 17p-estradiol.The results showed that 17β-estradiol could reduce the activity of melanocytes and cell proliferation,increase the level of oxidative stress of melanocytes,and induce oxidative stress state of cells.After 17β-estradiol stimulation,ROS levels in melanocytes were increased,MMP was decreased,and oxidative damage and apoptosis were increased.Further detection of melanocyte function showed that after stimulated by 17β-estradiol,the content of melanin and the activity of tyrosinase were decreased compared with the normal group,suggesting that β-estradiol can affect the function of melanocytes.ConclusionOur study is the first attempt to reveal urinary metabolic signatures of vitiligo patients and provides new insights into the metabolic mechanisms of vitiligo.And showing that 17β-estradiol can induce oxidative stress in melanocytes,which may be involved in the development of vitiligo.