| Backgrounds: Pulmonary hypertension(PH)is one of the main causes of right heart failure and sudden death.According to the etiology and pathogenesis of pulmonary hypertension,pulmonary hypertension is divided into five categories internationally,of which pulmonary hypertension caused by left heart disease(Pulmonary hypertension due to left heart disease,PH-LHD)belongs to the second category,which is the most common PH type.The increase in left ventricular load is caused by left heart disease(including heart failure and valvular heart disease),which will increase pulmonary venous pressure,which will lead to pulmonary vascular remodeling and PH.However,some studies have pointed out that after PH is formed,even if the factors that cause pressure increase are removed,pulmonary vascular remodeling and PH continue to develop,suggesting that there are other mechanisms for left heart disease to cause pulmonary hypertension.Pulmonary hypertension is an important cause of aggravating the symptoms of patients with left heart disease and is closely related to the prognosis.PH-LHD is difficult to be detected and diagnosed early in the clinic.In recent years,biomarkers have been a hot spot in the diagnosis of PH.Among them,brain natriuretic peptide,IL-6,uric acid,which are related to the prognosis of PH patients,but they lack good specificity for the early diagnosis of PH.At present,metabolomics has been successfully used in the discovery and intervention of biomarkers and related pathways for various cancers and chronic diseases such as diabetes and coronary heart disease.Therefore,non-targeted metabolomics technology was used to screen the plasma metabolic markers of PH-LHD to provide clues for finding specific biomarkers.Objectives: By establishing a model of transverse aortic constriction(TAC)in rats,the effect of increased left cardiac load on pulmonary hemodynamics,pulmonary vascular remodeling,and right cardiac function.And using non-targeted metabolomics technology to screen plasma metabolic markers of pulmonary hypertension caused by left heart insufficiency,with a view to laying an experimental foundation for the study of the pathogenesis and early diagnosis of pulmonary hypertension caused by left heart disease.Methods Part I: 1.Animal model: Sixty healthy male SD rats were randomly divided into normal group(Sham),3-week surgery group(TAC 3W),6-week surgery group(TAC 6W),9-week surgery group(TAC 9W),each group N = 15.The TAC group used a 16 G needle to narrow the aortic arch.The Sham group had the same procedure as the TAC group but did not narrow the aortic arch.2.Verification of the models:1)Basic physiological indicators;2)Cardiac ultrasound to detect cardiac function and remodeling in rats;3)Cardiac catheterization to detect hemodynamic changes;4)Pathological observation of myocardial size,fibrosis and pulmonary vascular remodeling.Part II: Using non-targeted metabolomics technology to screen plasma metabolic markers of PH-LHD using plasma samples from each group of rats,and using significantly different metabolites to construct ROC curve for predictive value analysis,and calculate the area under the curve,sensitivity and specificity.Result: Part I: 1.During the operation,9 rats in TAC group died due to anesthesia accident,pneumothorax and aortic rupture;during the feeding process,purple blue was observed in the limbs and chest of TAC group model,and the mental state gradually declined,12 rats in TAC group died,and 6 rats in sham group died.24 TAC models and 9 Sham models were obtained finally.2.Ultrasound examination showed that after the aortic arch narrowed,the left ventricular end-diastolic diameter(LVID;d)increased in the surgical group compared with the control group at each time point(TAC 3 weeks vs Control,5.94±0.29 mm vs 5.42±0.38 mm,P<0.05;TAC 6 weeks vs Control,6.62±0.79 mm vs 5.42±0.38 mm,P<0.05;TAC 9 weeks vs Control,6.47±0.88 mm vs 5.42±0.38 mm,P<0.05);the diastole left ventricular posterior wall(LVPW;d)increased in the surgical group compared with the control group at each time point(TAC 3 weeks vs Control,1.95±0.22 mm vs 1.44±0.27 mm,P<0.05;TAC 6 weeks vs Control,2.86±0.53 mm vs 1.44±0.27 mm,P<0.05;TAC 9 weeks vs Control,2.64±0.30 mm vs 1.44±0.27 mm,P<0.05);the left ventricular end diastolic volume(LVEDV)increased in the surgical group compared with the control group at each time point(TAC 3 weeks vs Control,198.61±24.96 ul vs 164.27±25.78 ul,P<0.05;TAC 6 weeks vs Control,237.92±25.85 ul vs 164.27±25.78 ul,P<0.05;TAC 9 weeks vs Control,278.57±43.09 ul vs 164.27±25.78 ul,P<0.01).3.Cardiac catheterization test showed that after the aortic arch was narrowed,the m PAP increased in the operation group at each time point compared with the control group(TAC 3 weeks vs Control,15.81±0.78 mm Hg vs 14.15±0.13 mm Hg,P>0.05;TAC 6 weeks vs Control,19.53±0.97 mm Hg vs 14.15±0.13 mm Hg,P<0.05;TAC 9 weeks vs Control,30.08±1.07 mm Hg vs 14.15±0.13 mm Hg,P<0.01);and the RVSP increased in the operation group at each time point compared with the control group(TAC 3 weeks vs Control,23.73±0.97 mm Hg vs 21.70±1.06 mm Hg,P>0.05;TAC 6 weeks vs Control,34.87±0.95 mm Hg vs 21.70±1.06 mm Hg,P<0.05;TAC 9 weeks vs Control,42.65±0.87 mm Hg vs 21.70±1.06 mm Hg,P<0.01).4.Pathological examination showed that after the aortic arch was narrowed,the cross sectional area of left cardiac myocytes increased in the operation group at each time point compared with the control group(TAC 3 weeks vs Control,348.6±9.7?m~2 vs 283.2±6.8?m~2,P<0.05;TAC 6 weeks vs Control,419.2±11.7?m~2 vs 283.2±6.8?m~2,P<0.01;TAC 9 weeks vs Control,459.7±12.9?m~2 vs 283.2±6.8?m~2,P<0.01);and the fibrosis degree of left cardiac myocytes increased in the operation group at each time point compared with the control group(TAC 3 weeks vs Control,4.84±0.21% vs 3.11±0.15%,P<0.05;TAC 6 weeks vs Control,8.02±0.33% vs 3.11±0.15%,P<0.01;TAC 9 weeks vs Control,10.17±0.30% vs 3.11±0.15%,P<0.01);and the thickening degree of middle layer of pulmonary arteriole increased in the operation group at each time point compared with the control group(TAC 3 weeks vs Control,16.2±0.9% vs 11.4±0.7%,P>0.05;TAC 6 weeks vs Control,25.7±2.3% vs 11.4±0.7%,P<0.01;TAC 9 weeks vs Control,36.1±1.4% vs 11.4±0.7%,P<0.01).Part II: A total of 153 plasma metabolites were detected using GC-TOFMS and UPLC-QTOFMS using rat plasma samples from each group.A prediction model for cholelithiasis including ten of these metabolites(Uracil?Palmitic acid?Arachidonic Acid ? Glyceric acid ? Allantoin ? D-Mannose ? L-Leucine ? Hippuric acid ?Phosphorylcholine ?Acetylcarnitine)yielded an area under the ROC curve(AUC)of 0.98,with sensitivity of 97.4% and specificity of 92.6%.Conclusion 1.The narrowing of the aortic arch can not only increase left cardiac load and decrease left cardiac function,but also increase pulmonary artery pressure and slightly damage right cardiac function.2.When the narrowing of the aortic arch makes the left heart pressure load increase and the left heart dysfunction and pulmonary artery pressure increase,the plasma metabolism profile of each model group changes significantly.The prediction model PH-LHD by 10 perturbed metabolites might be used to distinguish TAC group from Sham group. |
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