The different response of cardiomyocytes and cardiac fibroblasts to mitochondria inhibition and the underlying role of STAT3.

Cardiomyocyte loss and cardiac fibrosis are the main characteristics of cardiac ischemia and heart failure, and mitochondrial function of cardiomyocytes is impaired in cardiac ischemia and heart failure, so the aim of this study is to identify fate variability of cardiomyocytes and cardiac fibroblasts with mitochondria inhibition and explore the underlying mechanism. The mitochondrial respiratory function was measured by using Oxygraph-2k high-resolution respirometry. The STAT3 expression and activity were evaluated by western blot. Cardiomyocytes and cardiac fibroblasts displayed different morphology. The mitochondrial respiratory function and the expressions of mitochondrial complex I, II, III, IV, and V of cardiac fibroblasts were lower than that of cardiomyocytes. Mitochondrial respiratory complex I inhibitor rotenone and H2O2 (100 µM, 4 h) treatment induced cell death of cardiomyocyte but not cardiac fibroblasts. The function of complex I/II was impaired in cardiomycytes but not cardiac fibroblasts stimulated with H2O2 (100 µM, 4 h) and in ischemic heart of mice. Rotenone and H2O2 (100 µM, 4 h) treatment reduced STAT3 expression and activity in cardiomyocytes but not cardiac fibroblasts. Inhibition of STAT3 impaired mitochondrial respiratory capacity and exacerbated H2O2-induced cell injury in cardiomycytes but not significantly in cardiac fibroblasts. In conclusion, the different susceptibility of cardiomyocytes and cardiac fibroblasts to mitochondria inhibition determines the cell fate under the same pathological stimuli and in which STAT3 plays a critical role.

Characterizations of mitochondrial uncoupling induced by chemical mitochondrial uncouplers in cardiomyocytes.

Induction of mild mitochondrial uncoupling is protective in a variety of disorders; however, it is unclear how to recognize the mild mitochondrial uncoupling induced by chemical mitochondrial uncouplers. The aim of the present study is to identify the pharmacological properties of mitochondrial uncoupling induced by mitochondrial uncouplers in cardiomyocytes. Neonatal rat cardiomyocytes were cultured. Protein levels were measured by using western blot technique. The whole cell respiratory function was determined by using high-resolution respirometry. The typical types of chemical mitochondrial uncouplers, carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP), niclosamide, and BAM15, induced biphasic change of STAT3 activity in cardiomyocytes, activating STAT3 at low dose and inhibiting STAT3 at high dose, though the dose range of these drugs was distinct. Low-dose uncouplers induced STAT3 activation through the mild increase of mitochondrial ROS (mitoROS) generation and the subsequent JAK/STAT3 activation in cardiomyocytes. However, high-dose uncouplers induced inhibition of STAT3, decrease of ATP production, and cardiomyocyte death. High-dose uncouplers induced STAT3 inhibition through the excessive mitoROS generation and the decreased ATP -induced AMPK activation. Low-dose mitochondrial uncouplers attenuated doxorubicin (DOX)-induced STAT3 inhibition and cardiomyocyte death, and activated STAT3 contributed to the cardioprotection of low-dose mitochondrial uncouplers. Uncoupler-induced mild mitochondrial uncoupling in cardiomyocytes is characterized by STAT3 activation and ATP increase whereas excessive mitochondrial uncoupling is characterized by STAT3 inhibition, ATP decrease and cell injury. Development of mitochondrial uncoupler with optimal dose window of inducing mild uncoupling is a promising strategy for heart protection.

Regression equations for calculation of z scores for echocardiographic measurements of left heart structures in healthy Han Chinese children.

OBJECTIVE: Clinical decision making in children with heart disease relies on detailed measurements of cardiac structures using two-dimensional and M-mode echocardiography. However, no echocardiographic reference values are available for the Chinese children. We aimed to establish z-score regression equations for left heart structures in a population-based cohort of healthy Chinese Han children. METHOD: Echocardiography was performed in 545 children with a normal heart. The dimensions of the aortic valve annulus (AVA), aortic sinuses of Valsalva (ASV), sinotubular junction (STJ), ascending aorta (AAO), left atrium (LA), mitral valve annulus (MVA), interventricular septal end-diastolic thickness (IVSd), interventricular septal end-systolic thickness (IVSs), left ventricular end-diastolic diameter (LVIDd), left ventricular end-systolic diameter (LVIDs), left ventricular posterior wall end-diastolic thickness (LVPWd), left ventricular posterior wall end-systolic thickness (LVPWs) were measured. Regression analyses were conducted to relate the measurements of left heart structures to body surface area (BSA). Left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) were calculated. Several models were used, and the adjusted R2 values were compared for each model. RESULTS: AVA, ASV, STJ, AAO, LA, MVA, IVSd, IVSs, LVIDd, LVIDs, LVPWd, and LVPWs had a cubic relationship with BSA. LVEF and LVFS fell within a narrow range. CONCLUSIONS: Our results provide reference values for z scores and regression equations for left heart structures in Han Chinese children. These data may help make a quick and accurate judgment of the routine clinical measurement of left heart structures in children with heart disease.

Regression equations for calculation of z scores for echocardiographic measurements of right heart structures in healthy Han Chinese children.

OBJECTIVE: Clinical decision making in children with congenital and acquired heart disease relies on measurements of cardiac structures using two-dimensional echocardiography. We aimed to establish z-score regression equations for right heart structures in healthy Chinese Han children. METHODS: Two-dimensional and M-mode echocardiography was performed in 515 patients. We measured the dimensions of the pulmonary valve annulus (PVA), main pulmonary artery (MPA), left pulmonary artery (LPA), right pulmonary artery (RPA), right ventricular outflow tract at end-diastole (RVOTd) and at end-systole (RVOTs), tricuspid valve annulus (TVA), right ventricular inflow tract at end-diastole (RVIDd) and at end-systole (RVIDs), and right atrium (RA). Regression analyses were conducted to relate the measurements of right heart structures to 4body surface area (BSA). Right ventricular outflow-tract fractional shortening (RVOTFS) was also calculated. Several models were used, and the best model was chosen to establish a z-score calculator. RESULTS: PVA, MPA, LPA, RPA, RVOTd, RVOTs, TVA, RVIDd, RVIDs, and RA (R2 = 0.786, 0.705, 0.728, 0.701, 0.706, 0.824, 0.804, 0.663, 0.626, and 0.793, respectively) had a cubic polynomial relationship with BSA; specifically, measurement (M) = ß0 + ß1 × BSA + ß2 × BSA2 + ß3 × BSA.3 RVOTFS (0.28 ± 0.02) fell within a narrow range (0.12-0.51). CONCLUSIONS: Our results provide reference values for z scores and regression equations for right heart structures in Han Chinese children. These data may help interpreting the routine clinical measurement of right heart structures in children with congenital or acquired heart disease. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 45:293-303, 2017.

Association between renal dysfunction and 3-year mortality in patients with acute first-ever ischemic stroke.

OBJECTIVE: The influence of renal dysfunction on the clinical presentation and outcomes of patients with acute ischemic stroke is still controversial. We investigate the influence of renal dysfunction on the outcomes of patients with acute first-ever ischemic stroke. METHODS: Nine-hundred thirty-four patients with acute first-ever ischemic stroke were enrolled and followed for 3 years. Renal function was assessed using the equation of the Modification Diet for Renal Disease for estimated glomerular filtration rate (eGFR). Serum creatinine levels were obtained within 3 days of acute stroke onset. Reduced eGFR was defined as eGFR<60ml/min/1.73m(2). Clinical presentation, risk factors for stroke, laboratory data, co-morbidities, and outcomes were recorded. RESULTS: Total 264 patients (28.3%) had a reduced eGFR. The prevalence of older age, hypertension, and atrial fibrillation was significantly higher in patients with a reduced eGFR. Total anterior circulation syndrome occurred more frequently among patients with a reduced eGFR (P=0.010). Multivariate Cox regression revealed that a reduced eGFR is a significant predictor of 3-year mortality (HR=1.67, 95% CI=1.06-2.62, P=0.026). CONCLUSION: Reduced eGFR during the acute stroke stage is associated with increased risk of 3-year mortality. Furthermore, risk of acute complications and poor functional outcomes following discharge was significantly higher in patients with a reduced eGFR.

Coronary artery indexed diameter and z score regression equations in healthy Chinese Han children.

OBJECTIVE: In children with coronary disease, clinical decision should be based on detailed measurements of the coronary arteries by two-dimensional echocardiography. We aimed to establish coronary artery reference indexed diameter and z scores regression equations in a large cohort of Chinese Han children. METHODS: We measured the diameter of the proximal right (RCA), left main (LMCA), left anterior descending, and left circumflex coronary artery, and of the aortic annulus, and calculated the coronary-aorta index (coronary artery-to-aortic annulus ratio) in 506 Chinese Han children with normal hearts whose ages ranged from 1 day to 18 years. Regression analyses were performed, relating the coronary artery dimensions to body surface area (BSA). Several models were used, and the best model (yielding the maximum adjusted R(2) ) was chosen to establish a z score calculator. RESULTS: Based on cubic regression, (M) = ß0 + ß1 × BSA + ß2 × BSA(2) + ß3 × BSA(3) , the adjusted R(2) values were 0.515, 0.553, 0.505, and 0.518 for the RCA, LMCA, left anterior descending, and left circumflex coronary artery models, respectively. RCA/aortic annulus was 0.14 ± 0.02 (range, 0.07-0.24) and LMCA/AOA was 0.15 ± 0.03 (range, 0.10-0.28). CONCLUSIONS: Our results provide reference values of coronary artery z scores, regression equation, and coronary-aorta index as a quick guide to determine coronary dilation in Chinese Han children.