Changes Of Plasma Tris(hydroxymethyl) Aminomethane And 5-guanidino-3-methyl-2-oxopentanoic Acid As Biomarkers Of Cardiac Reverse Remodeling After Left Ventricular Assist Device Support

Part 1 Changes of Plasma Tris(hydroxymethyl)aminomethane and 5-Guanidino-3-methyl-2-oxopentanoic Acid as Biomarkers of Cardiac Reverse Remodeling after Left Ventricular Assist Device Support Background and ObjectivesCardiac function is closely related to heart metabolism.A few patients supported with left ventricular assist device(LVAD)have experienced recovery of cardiac function and cardiac morphology,and the heart underwent reverse remodeling(R).However,the characteristics of such patients have not yet been identified.The aim of this study is to determine metabolic differences between patients with cardiac R and those with cardiac non-reverse remodeling(NR),and screen for biomarkers of cardiac R.MethodsA total of 16 patients receiving LVAD support were included in this study.Patients were divided into two groups,those with and without cardiac R,according to changes in left ventricular ejection fraction and left ventricular end-diastolic diameter of pre-and post-LVAD echocardiography.Subsequently,after extracting metabolites from the patient’s preoperative and postoperative plasma,untargeted metabolomics was used to determine the levels of metabolites.Multivariate statistical analysis and a Mann-Whitney U-test was performed to clarify the separation in metabolites and to identify changes in plasma metabolites between the two groups,respectively.The receiver operating characteristic(ROC)curve was utilized to screen for the biomarkers of cardiac R.ResultsUsing the Metabolomics Standards Initiative level 2,a total of 1 542 and 619 metabolites were detected in the positive and negative ion modes by untargeted metabolomics on the plasma of 6 cardiac R and 10 cardiac NR patients.The functional enrichment analysis of metabolites with significant differences between the two groups was carried out.The results showed that the major functions of metabolites significantly increased in the R group were enriched in carbohydrate and amino acid pathway.However,the main function of metabolites significantly increased in the NR group was enriched in hormone metabolism.According to the area under the ROC curve,we found two metabolites,Tris(hydroxymethyl)aminomethane and 5-Guanidino-3-methyl-2-oxopentanoic acid could be selected as biomarkers of cardiac R.ConclusionThis study fully clarified the differential metabolites between patients with cardiac R and cardiac NR,and the function of metabolite affect cardiac R after LVAD support.Tris(hydroxymethyl)aminomethane and 5-guanidino-3-methyl-2-oxovaleric acid were identified as biomarkers of cardiac R after LVAD support for the first time.Part 2: Study on the Inhibition of IFNGR1 by Ruxolitinib to Alleviate Acute Cellular Rejection in Heart TransplantationBackground and objectivesThe acute cellular rejection mediated by T cell activation after heart transplantation(HTx)affects the postoperative survival rate of patients.Induction immunosuppressive therapy cannot significantly inhibit T cell activation.The aim of this study is to identify the key molecule that increases T cell activation and explore the therapeutic effect of targeted intervention on reducing acute cellular rejection.MethodsThis study first identified the genes responsible for the increased expression of T cells after HTx through gene differential analysis.Subsequently,a cervical heterotopic HTx model was constructed using BALB/C mice as donors and C57BL/6 mice as recipients.Subsequently,we inhibited the gene increased expressed in T cells.Flow cytometry,immunostaining,and q PCR were used to determine cell infiltration and activation in the mouse model,and survival analysis was used to determine the therapeutic effect.ResultsThis study found that IFNGR1 promoted T cell activation,which could not be inhibited by IL2 R monoclonal antibodies.Subsequently,IFNGR1 inhibitor ruxolitinib was used to treat the HTx mouse model.The results showed that ruxolitinib could significantly reduce cardiac graft congestion and edema,myocardial cell damage,and immune cell infiltration in HTx mouse model.In addition,ruxolitinib could reduce the secretion of pro-inflammatory cytokines and cytotoxic particles by T cells.Targeted inhibition of IFN-γ-IFNGR1-JAK1/JAK2 signaling axis by ruxolitinib inhibited T cell activation,thereby significantly prolonging the survival time of grafts.ConclusionThis study confirmed that IFNGR1 could promote T cell activation and mediate acute cellular rejection.Ruxolitinib could significantly inhibit immune response activation,reduce acute cellular rejection,and thus prolong survival time.