Study On Metabolomics Of Tetralogy Of Fallot Infants Using Hydro-nuclear Magnetic Resonance Spectrometer

Background:Tetralogy of Fallot (TOF) is the common cyanosis congenital heart disease. Rightventricular (RV) dysfunction is an important cause of morbidity and mortality after surgicalcorrection of TOF. Transatrial/transpulmonary repair avoids a ventriculotomy (in contrast tothe transventricular approach) aiming to preserve right ventricular structure and function.We performed a prospective randomised controlled trial in infancy with TOF undergoingthe primary repair.Tranexamic acid (TA) is an antifibrinolytic agent, which faces difficulties in theachievement and maintenance of a therapeutic concentration. Hence, it is required tomonitor the TA level in blood/plasma during the administration.Metabolomics is a powerful new technology that allows for the assessment of globalmetabolic profiles in easily accessible biofluids and biomarker discovery in order todistinguish between diseased and non-diseased status. We utilized this approach in a pilotstudy in urine and intact myocardium samples from TOF patients and controls. Todistinguish TOF patients from matched controls with the global metabolic profiling andsubsequent multivariate analysis. To explore the urine metabonomic profile of TOF patientsbefore and during cardiopulmonary bypass.To detect specimens of hypertensive myocardium with high resolution magic anglespinning1-Hydrogen Nuclear Magnetic Resonance spectroscopy(HR-MAS~1H-NMRS)，toanalyze their soluble metabolites，discuss its metabolism response to chronic hypoxia inmyocardium．1. Primary repair of Tetralogy of Fallot in infants: transatrial/transpulmonary ortransventricular approach.A prospective controlled clinical trial was conducted in infancy with TOF undergoingthe primary repair. One-hundred and six patients recruited were divided into transatrial-transpulmonary approach group (Group A)(n=53) and transventricular approachgroup (Group B)(n=53) depending on the different surgical technique.2. The plasma and urine concentration of tranexamic acid duringcardiopulmonary bypass in infants10patients with Tetralogy of Fallot received an initial dose100mg/kg of TA givenover10min followed by an infusion of100mg/kg before the initiation of cardiopulmonarybypass (CPB). Plasma and urine TA concentrations were detected by~1H NMR.3. Study on Urine Metabolomics of Tetralogy of Fallot Infants using Hydro-Nuclear Magnetic Resonance SpectrometerTotal10infants with Tetralogy of Fallot (TOF) and10healthy infants were enrolled inthis study and their urine metabolites were analyzed using Hydro-Nuclear MagneticResonance (~1H NMR) spectrometer for the Partial Least Squares Discriminant Analysis(PLS-DA).4. Study on Urine Metabolomics of Tetralogy of Fallot patients during theCardiopulmonary Bypass PeriodThe urine metabolites from total10TOF infants before and during thecardiopulmonary bypass period were detected by~1HNMR spectrometer analyzed for thePartial Least Squares Discriminant Analysis (PLS-DA).5.Intact myocardium metabolomics based on the HR-MAS~1H-NMRspectroscopy.There were total10infancy myocardiums from the right ventricular outflow tract withcyanotic (n=5) or acyanotic cardiac defects (n=7) were detected by HR-MAS~1H-NMRspectroscopy.Results1. Patient preoperative characteristics and procedure-related variables were similar.There was no death in Group A, while2patients died in Group B. There were significantdifferences in CPB time (95.02±23.8minutes versus85.23±22.63minutes, p=0.032),Cross-clamp time (69.4±10.36minutes versus61.17±9.38minutes, p=0.035), inotropicsupport (1.63±0.97days versus2.1±1.09days, p=0.02), intubation time (26.62±12.48hoursversus33.02±17.55hours, p=0.033), ICU stays (2.25±1.28days versus2.85±1.46days,p=0.026) and the incidence of arrhythmia (3,5.7%versus10,18.9%, p=0.038). No significant difference in RV/LV pressure ratio and hospital stay.2. Plasma TA concentrations were (224.61±195.28)ug/ml at20min after bolus,(509.58±181.57)ug/ml after60min on CPB,(243.95±32.30)ug/ml at the end of operation.Urine TA concentrations(mg/mL; M±SD) before CPB、during CPB、thoracic closing,4.28±1.12；3.7±2.86；4.45±2.65mg/ml respectively.Total urine TA dose(mg; M±SD)before CPB,during CPB, and thoracic closing,199.7±142.1,341.6±302.3,400.1±357.0mg/lrespectively.The total TA excreted (M±SD) is57.48±19.66%until operation finished about3hours.3. PLS-DA of urine~1H-NMR spectra revealed different metabolic spectra betweenTOF and the healthy control.The urine concentration of dimethylmine(δ2.76), trimethylmine(δ2.82)mandhippurate(δ7.82) is decreased significantly in TOF group compared with the control,(p=0.028,0.043,0.002, respectively), the urine concentration of bile acid(δ0.623) isencreased significantly in TOF group compared with the control,(p=0.03).4. PLS-DA of urine~1H-NMR spectra revealed different metabolic spectra betweenbefore and during CPB, demonstrated that the metabolic characteristics of the two groupswere significantly different. Compared with before operation, Leucine(δ0.93)，isoleucine(δ0.96,1.02)， valine(δ0.99,1.06), isovalerate(δ1.13,1.35,1.60,2.03),glutamine(δ2.44),Citrate(δ2.53)， succinic acid(δ2.71), α-ketoglutarate(δ3.01), creatine(δ3.04，4.04),Hippurate(δ7.82), Nicotinamide (δ8.32)，Formic acid(δ8.44)，decreased significantly duringCPB, while exogenous Mannitol(δ3.67)encreased significantly.5. PLS-DA of myocardium NR-MAS~1H-NMR spectra revealed different metabolicspectra between TOF and control, demonstrated that the metabolic characteristics of the twogroups were significantly different. Only the triglyceride(δ1.31) is higher significant in theTOF myocardium than that of control.Conclusion1. Transatrial/transpulmonary repair of TOF is associated with excellent surgicalresults and immediately follow-up.2. A100mg/kg initial dose of TA followed by an infusionof100mg/kg before theinitiation of CPB is sufficient enough to provide an effective plasma concentration125ug/ml for the bleeding patients with high risk. The dose of TA could be decreased. About50%of total dose excreted off in3hours.3. Chronic Hypoxia alters metabolism of intestinal flora in infants.4．Characteristic metabolic products in two groups can be identified by~1H-NMR basedmetabonomics analysis. Metabonomic study is a feasible and promising way to detect thevariation of urine metabonomics of complex open heart operation patients.5. Chronic hypoxia effect the energy metabolism of myocardium and the key enzymeof fatty acid oxidative metabolism in the myocardial mitochondria.These findings highlight the potential of metabonomics as a novel approach forfundamental investigations of hypoxia interactions as well as for disease surveillance andcontrol. It holds promise for development of novel diagnostic approaches at individual andpopulation levels. Future studies should look at extending this work to other aged patientsmodels. We believe that metabonomics also represents an ‘omics’ science that now requirescomprehensive assessment and validation for its potential in individual and communitydiagnosis, particularly with regard to responses to treatment.