Preliminary Study On Serum Metabolic Profiling Of Gout Patients Based On UPLC-Q-TOF/MS

Background:Gout is a kind of acute/chronic inflammation and tissue damage caused by the deposition of monosodium urate in bones,joints,kidneys,and subcutaneous areas,and is directly related to hyperuricemia caused by impaired purine metabolism and/or decreased uric acid excretion.However,the detailed pathogenesis of gout has not yet been fully clarified.Detection of urate crystals in the synovial fluid,serum uric acid,and inflammatory indicators such as erythrocyte sedimentation rate(ESR)and C-reactive protein(CRP)are usually used to assist with the diagnosis of gout.However,the sensitivity or specificity of these indicators is not high,which calls for further study of pathogenesis and diagnostic biomarkers of gout.Metabolomics is an important technology for exploring disease pathogenesis and diagnostic markers.The most common used metabolomic analysis tools include nuclear magnetic resonance(NMR),gas chromatography-mass spectrometry(GC-MS),and liquid chromatography-mass spectrometry(LC-MS),which have recently been successfully applied in the study of gout and made a series of achievements.Ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF/MS)is a new metabolomic analysis tool with the advantages of fast speed,high resolution,high sensitivity and so on.However,metabolomic analysis of gout using UPLC-Q-TOF/MS is rare.Objective:The study aims to investigate the serum metabolic profiling of gout patients with UPLC-Q-TOF/MS to find potential biomarkers and explore pathological mechanisms.Methods:Serum samples from 31 gout patients and 31 healthy controls were analyzed by UPLC-Q-TOF/MS.Principal components analysis(PCA)and orthogonal partial least squares-discriminant analysis(OPLS-DA)were performed to detect differential compounds between two groups.Clustering heatmap was drawn to show the relative levels of differential compounds and clustering effect of the two groups.Then the compounds were matched with Human Metabolome Database(HMDB)and specific metabolites were detected.Receiver operating characteristic(ROC)curve analysis was carried out to determine the utility of metabolites for the diagnosis of gout.Furthermore,pathway analysis was used to analyze the disturbed metabolic pathways related to gout.Results:A total of 9192 compounds were detected,of which 138 significantly different compounds were selected,according to the criteria of(Variable importance in projection(VIP)>3).Clustering heatmap analysis directly showed that the relative levels of the differential compounds were different between the two groups and the clustering effect was good.Eventually,91 specific metabolites matching the HMDB database were confirmed.The results of ROC curve analysis revealed that there were 10 substances with the area under the curve(AUC)greater than 0.8,of which 4-hydroxytriazolam,uric acid,bilirubin exerted better AUC values.The pathway analysis results indicated that the significantly different metabolites were mainly involved in primary bile acid biosynthesis,purine metabolism,glycerophospholipid metabolism,glycosylphosphatidylinositol-anchor biosynthesis,porphyrin and chlorophyll metabolism,and arginine and proline metabolism,of which primary bile acid biosynthesis was mostly affected.Conclusion:These findings suggest significant serum metabolic difference between gout patients and healthy controls.In addition to uric acid,some metabolites like bilirubin have good diagnostic value of gout,which may serve as potential diagnostic biomarkers.Primary bile acid biosynthesis,purine metabolism,glycerophospholipid metabolism,glycosylphosphatidylinositol-anchor biosynthesis,porphyrin and chlorophyll metabolism,and arginine and proline metabolism are associated with gout and primary bile acid biosynthesis is the most relevant,which may provide new insight into the pathological mechanisms of gout.