Study On Biomarkers For Traumatic Brain Injury Based On Metabolomics

ObjectiveTraumatic brain injury(TBI)is a nervous system injury caused by external mechanical force,and is a major cause of death and disability worldwid.This study intends to identify the changes of metabolites and metabolic pathways in cerebrospinal fluid(CSF)of TBI rats and patients by using High performance liquid chromatography mass spectrometry-mass spectrometry(HPLC-MS/MS)technology and to screen out potential biomarkers that can be used for TBI assessment and prognosis.MethodsIn the first part of this study,a TBI rat model was established.Twenty-four SD rats were divided into a model group and a control group(n=12).The rats in the model group used an acrylic hammer to fall freely to cause craniocerebral injury,while the control group underwent none of the treatments.Rats in the model group were given a modified neurological severity score(mNSS)on days 1,3,and 7 after modeling.Both groups of rats were collected CSF at the cisterna magna 24 hours after modeling.Using a metabolomics method based on HPLC-MS/MS,principal component analysis(PCA)and orthogonal oartial least squares-discriminant analysis(OPLS-DA)to find the difference of CSF metabolic profiles.Pathway analysis was performed with MetaboAnalyst 3.0.Receiver operating characteristic(ROC)analysis was used to determine the diagnostic value of the differential metabolites detected in TBI rats.In the second part of the study,19 TBI patients and 8 patients in the control group were collected,and cerebrospinal fluid was collected by lumbar puncture.TBI patients were given a GOSe score 3 months after discharge,with a 1-4 score indicating a poor prognosis and a 5-8 score indicating a good prognosis.Using a metabolomics method based on HPLC-MS/MS,PCA and OPLS-DA to find the difference of CSF metabolic profiles.Pathway analysis was performed with Metabo Analyst 3.0.The diagnostic value of the differential metabolites detected by ROC analysis in the prognosis of TBI patients.ResultsIn the first part,the rat TBI model was successfully established in the experiment.There were significant differences in the metabolic profiles in the CSF of the model group and the control group.Fourteen different metabolites were selected,including 3-Methyl-2-oxovaleric acid,4-hydroxyproline,alpha-ketobutyrate,arginine,Betaine,Choline,glutamine,lactate,L-Arginine,leucine,methionine,urea,valine and N-acetylaspartate.The affected metabolic pathways includs alanine,aspartate and glutamate metabolism,cysteine and methionine metabolism,arginine and proline metabolis,arginine biosynthesis and glycine,serine and threonine metabolis.According to ROC curve analysis,arginine,lactate,urea,and N-acetylaspartate are expected to be four biomarkers for early diagnosis of TBI.In the second part,there were significant differences in the metabolic profiles of cerebrospinal fluid in TBI patients and control patients,and twenty-three differential metabolites in CSF of TBI patients were screened.The metabolic pathways involved are:phenylalanine metabolism,phenylalanine,tyrosine and tryptophan biosynthesis,glycine,serine and threonine metabolism,alanine,aspartate and glutamate metabolism and Citrate cycl.Analysis of eight metabolites with AUC valuesgreater than 0.7 by ROC curve analysis includs N-Acetyl-D-asparticacid,glutamine,L-Phenylalanine,L-carnitine,L-carnitine,citric acid,Oxalacetic acid and lactate.The metabolome set composed of these 8 metabolites is expected to become a biomarker for the diagnosis of TBI prognosis.ConclusionThis experiment studied the characteristic metabolite profiles in the CSF of rats and patients with TBI from the perspective of metabolomics,respectively found a set of differential metabolites that are expected to be used for disease diagnosis,and found a series of metabolic changes in the body after TBI.The research results can provide scientific basis for the diagnosis,assessment,pathogenesis and in-depth study of TBI.