The Prediction Model And Pathogenesis Of Protein Biomarkers For ARDS Induced By Cardiopulmonary Bypass After Cardiac Surgery

ObjectivesThe incidence of acute respiratory distress syndrome(ARDS)after cardiopulmonary bypass(CPB)is high and the prognosis is poor.The prediction model and molecular mechanism of CPB-ARDS at early stage are important research priorities.The purpose of this study is:1.Preliminary identification of plasma predictive proteins of ARDS after cardiac surgery with CPB,based on proteomics and machine learning model.2.Establishing a prediction model of CPB-ARDS that combines protein and clinical factors.3.Exploring the mechanism of TXNDC5/e NOS signaling pathway in lung-blood barrier injury induced by ischemia and reperfusion.Methods1.A prospective nested case-control study design was used to screen adult patients who underwent cardiac surgery with CPB in the Union Hospital,Tongji Medical College,Huazhong University of Science and Technology.Blood samples were collected from all patients in the cohort before CPB(T1),immediately after CPB(T2),and 24 hours after CPB(T3)to obtain plasma.The patients were classified into either the CPB-ARDS or non-ARDS group based on whether they developed ARDS within 3 days after CPB operation,and matching factors were applied.Proteomics was used to detect the differentially expressed proteins(DEPs)in plasma between the two groups.Candidate predictive proteins were preliminarily screened from the DEPs using Lasso regression and Xgboost models.2.An independent clinical cohort of patients undergoing CPB surgery was established,and the candidate predictive protein at the T2 time point was quantitatively verified through the ELISA method.Subsequently,a difference test was conducted between the two groups,followed by a stepwise logistic regression model(SLR)to screen important clinical predictors.Next,a prediction model of CPB-ARDS was established by combining both protein and clinical factors.The model was thoroughly tested and evaluated based on the Nfold cross-validation approach.3.The lung ischemia-reperfusion injury(LIRI)model in SD rats was established by left hilar occlusion.The expression of lung tissue proteome and TXNDC5 after LIRI was detected through lung tissue proteomics,immunofluorescence,and other molecular biology methods.To assess the role of TXNDC5 in this model,the expression of TXNDC5 in the lung tissue was down-regulated by intratracheal injection of adeno-associated virus carrying TXNDC5 interfering RNA.The effect of TXNDC5 down-regulation on HSP90/e NOS and lung-blood barrier injury was then examined.Results1.In the cohort of 150 patients,20 were diagnosed with CPB-ARDS and were matched with 20 non-ARDS patients according to matching factors.Differential expression analysis was conducted for T1,T2,and T3,revealing 9,29,and 35 DEPs,respectively.Out of these,eleven candidate predictive proteins were identified in T2,and the top four proteins had a percent contribution exceeding 10%,indicating their importance in predicting CPBARDS.2.In a separate cohort of 375 patients,50 cases of CPB-ARDS were diagnosed and matched with 100 non-ARDS patients.The plasma concentrations of TXNDC5,CTSL,and NPC2 at T2 were found to be statistically different between the two groups(except CD56)using ELISA.After multivariable SLR analysis,based on three proteins(TXNDC5,CTSL and NPC2)and two clinical factors(CPB time and massive blood transfusion),an earlywarning model of CPB-ARDS was established,showing good prediction performance after N-fold cross-validation.Decision curve analysis indicated that the model had good clinical benefit.3.The lung injury score was the highest and the lung-blood barrier injury was serious in LIRI for 6 hours group.The lung tissue proteomics and immunofluorescence showed that the expression of TXNDC5 in rat lung tissue was up-regulated after LIRI,especially in lung endothelial cells.After down-regulation of TXNDC5 by RNA interference,the expression of e NOS and HSP90 protein increased,the degree of inflammation and oxidative stress improved,the damage of blood-gas barrier and the score of LIRI lung injury decreased.Conclusions1.Evaluation of plasma TXNDC5,CTSL and NPC2 levels can predict the high-risk patients with ARDS after CPB surgery,and targeted close follow-up and intensive treatment should be carried out to prevent the occurrence of ARDS during the perioperative period.2.The CPB-ARDS prediction model established by plasma predictive protein combined with clinical factors has high prediction accuracy,which may provide a more objective and accurate method for the use of biomarkers to assist CPB-ARDS prediction.3.After LIRI injury,the expression of TXNDC5 in lung endothelial cells is upregulated,which may promote the damage of blood-gas barrier by reducing the stable expression of HSP90/e NOS.