Alamandine attenuates sepsis-associated cardiac dysfunction via inhibiting MAPKs signaling pathways.

Sepsis-induced myocardial dysfunction represents a major cause of death. Alamandine is an important biologically active peptide. The present study evaluated whether alamandine improves cardiac dysfunction, inflammation, and apoptosis, and affects the signaling pathways involved in these events. Experiments were carried out in mice treated with lipopolysaccharide (LPS) or alamandine, and in neonatal rat cardiomyocytes. Alamandine increased the ejection fraction and fractional shortening, both of which were decreased upon LPS infusion in mice. LPS and alamandine reduced blood pressure, and increased the expression of inducible nitric oxide synthase (iNOS) and endothelial NOS (eNOS) in the heart in mice. The LPS-induced decrease in α-myosin heavy chain (MHC) and ß-MHC, and increase in S100 calcium binding protein A8 (S100A8) and S100A9, were reversed by alamandine pre-treatment. Alamandine pre-treatment prevented LPS-induced myocardial inflammation, apoptosis and autophagy. LPS increased p-ERK, p-JNK, and p-p38 levels, which were inhibited by alamandine. Dibutyryl cyclic AMP (db-cAMP) increased p-ERK, p-JNK, and p-p38 levels, and reversed the inhibitory effects of alamandine on the LPS-induced increase in p-ERK, p-JNK, and p-p38. Moreover, db-cAMP reduced the expression of α-MHC and ß-MHC in cardiomyocytes, and reversed the almandine-induced attenuation of the LPS-induced decrease in α-MHC and ß-MHC. These results indicate that alamandine attenuates LPS-induced cardiac dysfunction, resulting in increased cardiac contractility, and reduced inflammation, autophagy, and apoptosis. Furthermore, alamandine attenuates sepsis induced by LPS via inhibiting the mitogen-activated protein kinases (MAPKs) signaling pathways.

Brachial-ankle pulse wave velocity compared with mean arterial pressure and pulse pressure in risk stratification in a Chinese population.

BACKGROUND: Brachial-ankle pulse wave velocity (baPWV) can be easily measured in an observer-independent way, but lacks robust population-based validation in terms of fatal combined with nonfatal outcomes. METHOD: To address this issue, we studied 4251 Chinese randomly recruited Gaoyou County (54.1% women; mean age, 52.1). RESULTS: In the whole study population, mean values were 102.4 mmHg for mean arterial pressure (MAP), 51.1 mmHg for pulse pressure, and 14.8 m/s for baPWV. Over 4.4 years (median), 74 participants experienced a fatal or nonfatal cardiovascular event and 44 a stroke. In multivariable-adjusted Cox regression, standardized hazard ratios expressing the risk of a composite cardiovascular endpoint were 1.77 (95% confidence interval, 1.43-2.20), 1.37 (1.14-1.64) and 1.50 (1.26-1.78) for MAP, PP and baPWV, respectively; the corresponding hazard ratios for stroke were 1.82 (1.39-2.38), 1.39 (1.12-1.74) and 1.53 (1.25-1.89). baPWV did not add to the prediction of cardiovascular events or stroke by MAP (hazard ratios for baPWV, 1.25 and 1.27, respectively; P ≥ 0.053) but refined models including PP (hazard ratios, 1.42 and 1.45; P ≤ 0.0033). The optimized baPWV threshold, obtained by maximizing Youden's index (16.7 m/s), increased the integrated discrimination improvement over and beyond MAP (+1.27%; P = 0.021) and PP (+1.37%; P = 0.038) for the cardiovascular outcome, but not stroke, and increased the net reclassification improvement for both endpoints (≥42.2%; P ≤ 0.004). CONCLUSION: With fatal and nonfatal cardiovascular and cerebrovascular endpoints as outcome, baPWV marginally increases risk stratification over and beyond MAP, but is a better predictor than PP. A threshold of 16.7 m/s might be used in Chinese populations.

Hypertension related knowledge and behaviour associated with awareness, treatment and control of hypertension in a rural hypertensive population: a community based, cross-sectional survey.

BACKGROUND AND OBJECTIVE: Hypertension-related knowledge and behaviour have been identified as influential factors associated with awareness, treatment and control of hypertension in urban regions. However, there were few studies on rural areas. This study aims to investigate whether hypertension related knowledge and behaviour were associated with hypertension awareness, treatment and control in Gaoyou, a rural area of Jiangsu province, China. METHODS: A cross-sectional, population-based survey was conducted among hypertensive individuals in rural areas of Gaoyou, the south-eastern of China in 2010. We identified 1943 subjects with hypertension among 4536 subjects participated in this study and collected information about medical history, use of medication, hypertension related knowledge and behaviour by a standardized questionnaire. RESULTS: This study showed that 41.07% of subjects were aware of their disease, 30.01% of subjects were taking antihypertensive medication and 5.04% of subjects controlled their blood pressure. Multivariate logistic regression analysis showed that subjects who knew the threshold, the lifelong treatment of hypertension and measured blood pressure at least once a year had better detection, treatment or control of hypertension. CONCLUSION: Hypertension related knowledge and behaviour were associated with awareness, treatment and control rate of hypertension in the rural areas of south-eastern China.

Quality control of the blood pressure phenotype in the Gaoyou population study.

The Korotkoff approach is the only blood pressure (BP) measurement technique that allows contemporary data to be compared with decades of research. We randomly recruited 4483 people (53.3% women; mean age 52.1 years) from Gaoyou County, Jiangsu Province, China. Nine observers recorded the participants™ BP three times consecutively following Chinese Society of Hypertension guidelines. We assessed the BP phenotype based on five criteria: completeness of readings, percentage of identical BP readings, odd BP readings, end-digit preference and trends in BP from the first to the third reading. The proportion of participants with identical readings were 2.0% and 3.1% for systolic (SBP) and diastolic blood pressure (DBP), respectively. Among 26,898 BP values, 0.3% ended in an odd number. Among observers, the prevalence of identical readings varied from 0% to 5.3% for SBP and from 0% to 6.8% for DBP. Compared with the expected frequency of 20%, those ending in 0 had a lower frequency (17.2%; p < 0.001), whereas those ending in 8 had a higher frequency (22.4%; p < 0.001). From the first to the third measurement, SBP and DBP decreased (p < 0.001) by 0.87 and 0.55 mmHg, respectively. In conclusion, the procedures set up in the Gaoyou study produced a high-quality BP phenotype.

Dynamic mitochondrial changes during differentiation of P19 embryonic carcinoma cells into cardiomyocytes.

Murine P19 embryonal carcinoma cells are multipotent cells that can differentiate into cardiomyocytes when treated with dimethyl sulfoxide. This experimental model provides an invaluable tool to study different aspects of cardiac differentiation, such as the function of cardiac­specific transcription factors and signaling pathways, and the regulation of contractile protein expression. The role of mitochondria during cardiac differentiation is unclear. In this context, we have examined the mitochondrial-related changes in undifferentiated and differentiated P19 cells. We observed that mitochondrial DNA content sharply decreased in P19 cell aggregates compared to undifferentiated cells, accompanied by decreased levels of adenosine triphosphate (ATP) and reactive oxygen species (ROS). Following the aggregation stage, the mitochondrial DNA content reached its highest level on day 7 of the differentiation process, with the intracellular ROS level showing a trend to increase, similar to cellular ATP production. In conclusion, our study on differentiating P19 embryonal carcinoma cells provides new insights into the role of mitochondria in the differentiation of P19 stem cells into beating cardiomyocytes.

Overexpression of FABP3 promotes apoptosis through inducing mitochondrial impairment in embryonic cancer cells.

Fatty acid-binding protein 3 (FABP3) is a low-molecular-weight protein with a distinct tissue distribution that may play an important role in fatty acid transport, cell growth, cellular signaling, and gene transcription. Previously, we have found that FABP3 was involved in apoptosis-associated congenital cardiac malformations, but the underlying mechanisms have not yet been described. In the present study, we investigated the characteristics of mitochondrial dysfunction in embryonic cancer cells (P19 cells) that overexpressed FABP3. We demonstrated that in FABP3-overexpressing P19 cells a lower cellular ATP production was accompanied by a dramatic decrease in mitochondrial membrane potential (MMP), despite the lack of a substantial decrease in the mtDNA copy number. In addition, FABP3 overexpression also led to an imbalance in mitochondrial dynamics and to excess intracellular reactive oxygen species production. Collectively, our results indicated that overexpression of FABP3 in P19 cells caused mitochondrion dysfunction that might be responsible for the development of FABP3-induced apoptosis.

Silencing of FABP3 promotes apoptosis and induces mitochondrion impairment in embryonic carcinoma cells.

Fatty acid binding protein 3 (FABP3) (also known as H-FABP) is a member of the intracellular lipid-binding protein family, and is mainly expressed in cardiac muscle tissue. The in vivo function of FABP3 is proposed to be in fatty acid metabolism, trafficking, and cell signaling. Our previous study found that FABP3 is highly regulated in patients with ventricular septal defect (VSD), and may play a significant role in the development of human VSD. In the present study, we aimed to investigate the impact of FABP3 knockdown by RNA interference (RNAi) on apoptosis and mitochondrial function of embryonic carcinoma (P19) cells. The results revealed that downregulated FABP3 expression promoted apoptosis, and resulted in mitochondrial deformation, increased mitochondrial membrane potential (MMP), and decreased intracellular ATP synthesis. In addition, the knockdown of FABP3 also led to excess intracellular ROS production. However, there was no obvious influence on the amount of mitochondrial DNA. Collectively, our results indicated that FABP3 knockdown promoted apoptosis and caused mitochondrial dysfunction in P19 cells, which might be responsible for the development of human VSD.

Risk factors and outcomes of post-procedure heart blocks after transcatheter device closure of perimembranous ventricular septal defect.

OBJECTIVES: The aim of this study was to analyze the risk factors and mid-term outcomes associated with post-procedure heart blocks (PPHBs) after transcatheter closure of perimembranous ventricular septal defect (pmVSD). BACKGROUND: The development of heart blocks remains a major challenge for transcatheter closure of pmVSD. METHODS: Transcatheter closure of pmVSD was carried out in 228 patients. Electrocardiography and 24-h Holter monitoring were performed before the procedure, within 1 week after the procedure, then 1, 3, 6, and 12 months, and every year thereafter. RESULTS: Thirty-three patients (14.5%) who received transcatheter closure of pmVSD developed PPHBs. PPHBs included right bundle branch block (57.6%), left bundle branch block (24.2%), and atrioventricular block (18.2%). High-degree atrioventricular blocks occurred in 4 patients and recovered to normal conduction after intravenous administration of hydrocortisone. PPHBs recovered to normal conduction in 21 patients by the time of hospital discharge. Compared with the patients without PPHBs, the patients suffering PPHBs were characterized by a significantly longer distance between the aortic valve and the defect (DAVD), a shorter distance from the lower rim of the defect to the septal leaflet of the tricuspid valve (DLRD-SLTV), and a larger diameter difference between the occluder and ventricular septal defect (DDOV). The earlier the PPHBs developed after the procedure, the more difficult the recovery to normal conduction. CONCLUSIONS: The outcome of PPHBs after transcatheter closure of pmVSD was satisfactory, as most patients recovered to normal conduction. Measurements of DLRD-SLTV, DAVD, and DDOV may be useful in predicting the incidence of PPHBs.

Late recurrent high degree atrioventricular block after percutaneous closure of a perimembranous ventricular septal defect.

High degree atrioventricular block (HDAVB) is a serious complication of transcatheter closure of a perimembranous ventricular septal defect (PMVSD). We report one patient who developed transient HDAVB seven days after transcathter closure of PMVSD and had recurrent HDAVB 42 months after the procedure.

Differential expression of microRNAs in cardiac myocytes compared to undifferentiated P19 cells.

microRNA (miRNA) expression is tightly controlled in a tissue-specific and developmental stage-specific manner; some are highly and specifically expressed in cardiovascular tissues. miRNA expression profiling, using miRNA microarrays facilitates studying the biological function of miRNAs. We investigated changes in miRNA expression profiles during differentiation of P19 cells into cardiac myocytes in order to elucidate the mechanisms of heart development. The morphology of P19 cells during differentiation was observed using an inverted microscope. Western blot analysis was performed to detect cardiac troponin I (cTnI) expression. Total RNA was extracted from P19 cells for microarray and real-time quantitative reverse transcription-polymerase chain reaction (real-time qRT-PCR) analyses to determine the miRNA expression profile. The miRNA microarray revealed differential expression of 49 miRNAs, of which 26 were down-regulated and 23 were up-regulated in differentiated cardiac myocytes, compared to normal P19 cells. This was confirmed by real-time qRT-PCR. We also utilized target prediction analysis to identify gene targets. Some miRNAs may have important roles in cardiac development and congenital heart defects (CHDs). Further analysis of miRNA function to confirm their target genes during cardiac development will determine the potential for novel miRNA-based therapeutic strategies.

GATA-4 promotes the differentiation of P19 cells into cardiac myocytes.

The aim of this study was to investigate the effects of GATA-4 on the differentiation of P19 cells into cardiomyocytes and to examine the relationship between GATA-4 and cardiomyocytes. We constructed vectors to overexpress and silence GATA-4. These vectors, as well as empty ones were transfected into P19 cells. Subsequently, reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot analysis were performed. The morphology of P19 cells during differentiation was observed using an inverted microscope. Total RNA was extracted from P19 cells. We used real-time PCR to evaluate the expression levels of 6 genes: GATA-4, GATA-6, transthyretin (TTR), alpha-fetoprotein (AFP), Nkx2.5, and alpha-myosin heavy chain (alpha-MHC). The gene expression pattern of these 6 genes is graphically shown for each group. The GATA-4 mRNA level in cells overexpressing GATA-4 was notably higher than that in the controls, whereas the levels in the controls were notably higher than those in the GATA-4-silenced P19 cells. The cell lines overexpressing GATA-4 expressed higher levels of Nkx2.5 and alpha-MHC than the controls. However, the controls expressed higher levels of AFP, GATA-6 and TTR than the cells overexpressing GATA-4. The RNAi group expressed lower levels of TTR, Nkx2.5, and alpha-MHC than the controls, but there were no differences in the RNAi group and the controls with regard to the expression levels of AFP and GATA-6. The gene expression pattern in the cells overexpressing GATA-4 was biased toward the Nkx2.5 and alpha-MHC. On the other hand, the gene expression pattern in GATA-4-silenced cells and the controls was biased toward the TTR and AFP. The overexpression of GATA-4 enhances the differentiation of P19 cells into cardiac myocytes, whereas its down-regulation suppresses this trend.

[Generation of a P19-alphaMHC-EGFP reporter line and cardiomyocyte differentiation].

OBJECTIVE: To generate a P19-alphaMHC-EGFP reporter line and induce cardiomyocyte differentiation of this reporter line. METHODS: The P19 cells were transfected with palphaMHC-EGFP, a P19-alphaMHC-EGFP reporter line was obtained after G418 selection and limited dilution of recombinant clones. The reporter line was induced to differentiate into cardiomyocytes which would beat and express green fluorescent protein. A comparison of cardiomyocyte differentiation rate and cTnI expression amount between the reporter line and the untransfected P19 cells was also performed. The ultrastructure was observed under transmission electron microscope. RESULTS: The ultrastructure characteristics indicated cardiomyocytes-like changes on induction day 10. The beating cardiomyocytes which express GFP appear in the seventh induction day. The cardiomyocyte differentiation rate and cTnI expression amount of P19-alphaMHC-EGFP reporter line were similar as those in untransfected P19 cells (P > 0.05). CONCLUSION: The P19-alphaMHC-EGFP reporter line is of great benefit for identifying and purifying cardiomyocytes from undifferentiated P19 cells without influencing the differentiation of P19 cells. This feature makes P19-alphaMHC-EGFP reporter line a promising cell source for clinical cardiomyocyte replacement therapy.