Changes Of Metabolism In Patients With Nonalcoholic Steatohepatits

OBJECTIVE:Currently the incidence of nonalcoholic fatty liver disease(NAFLD)in China has been gradually increasing.NAFLD has become the most common reason for chronic liver diseases,especially in the US and other western countries.The incidence of NAFLD has also been on the rise in developed regions such as Shanghai,Guangzhou and Hong Kong in China.NAFLD is a key phase of the disease spectrum,therefore early diagnosis of nonalcoholic steatohepatitis(NASH)with noninvasive means is extraordinarily essential.With development of metabolomics in recent years,the analysis of NASH metabolic profiling with metabolomics and its research platform has become a hotspot.Based on metabolomics,this research made use of tandem mass spectrum(MS/MS)technology to research metabolomics difference in NASH and nonalcoholic fatty liver(NAFL)so as to find out potential metabolic markers for early diagnosis of NASH.METHOD:Patients with NASH and NAFL were included,30 cases for each.Dried blood spots collected were tested with liquid chromatography-tandem mass spectrum(LC-MS/MS)technology.Metabolic data acquired thereby were subject to multidimensional statistical analysis via principal component analysis and orthogonal partial least square(OPLS)method,and PCA and OPLS-DA models were established.The value of variable importance in projection(VIP)obtained through the OPLS-DA model was used to preliminarily screen metabolites,and potential metabolic markers were further screened based on independent-sample t test and Mann-Whitney U test;meanwhile,changes in blood metabolomics were analyzed via non-parametric test.Metabolites screened thereby were subject to ROC analysis with binary Logistic regression to calculate AUCs so as to evaluate their values for diagnosis of NASH.RESULT:There was statistic difference between NASH group and NAFL group in terms of blood metabolites,and for these two groups,a total of 30 metabolites showed statistic difference,p<0.05.Of them,for the NASH group,levels of Ala,Asn,Asp,Cys,Hcy,Glu,Leu,Orn,Met,Orn,C4-OH,Met/Phe,Orn/Cit,C3/C2,C5/C2,C5-OH/C8,C5-OH/C0 and C8/C10 increased while for the NASH group,levels of C5DC,C14DC,C14:1,Arg/Orn,Met/Leu,Phe/Tyr,C2/C0,C5DC/C5-OH,C5DC/C16,C14:1/C16,C3DC,C6DC and C5DC/C8 decreased.A total of 58 blood metabolites were tested for multidimensional statistical analysis to establish PCA(R~2X=0.468,Q~2=0.168)and OPLS-DA models(R~2X=0.653,R~2Y=0.74,Q~2=0.454).According to the value of VIP>1.5,6 metabolites that showed remarkable difference in both the NAFL group and the NASH group were selected,and then 5 metabolites showed difference were screened at last based on independent-sample t test and Mann-Whitney U test:Leu,Ala,Asp,Glu and Orn,and their AUCs were all higher than 0.6 and reached 0.932 upon combined diagnosis,the sensitivity reaching 83.3%and specificity 93.3%.CONCLUSION:1.Blood specimens of patients in the NAFL group and the NASF group(30 cases for each)were tested with LC-MS/MS technology,and t test or nonparametric test on them found difference in metabolism of amino acid and acyl carnitine between these two groups.2.By establishing OPLS-DA model,6 metabolites that showed remarkable difference compared with the NAFL group were preliminarily selected,and then 5potential metabolic markers were screened at last via t test and nonparametric test:Leu,Ala,Asp,Glu and Orn,and their AUCs reached 0.932 upon combined diagnosis,indicating high diagnosis value.