Effect of burden and origin sites of premature ventricular contractions on left ventricular function by 7-day Holter monitor

Recent studies have shown that premature ventricular contractions （PVCs） could enlarge the heart, but its risk factors are incompletely understood as a single 24-hour recording cannot reflect the true PVC burden due to day-to-day variability. Our purpose was to investigate the effect of burden and origin sites on left ventricular （LV） function in patients with PVCs by 7-day Holter electrocardiography （ECG）. From May 2012 to August 2013, 112 consecutive patients with PVCs were recruited from the authors＇ affiliated hospital. All patients received 2-dimensional transthoracic echocardiography, 12-lead routing ECG and 7-days Holter ECG. Serum N-terminal pro- brain natriuretic peptide （NT-proBNP） levels were measured. A total of 102 participants with PVCs were included in the final analysis. Origin of PVCs from the tricuspid annulus had the highest burden and NT-proBNP level. LV papillary muscle had a higher LV ejection fraction （EF） level and a lower LV end-systolic dimension （ESD） than other PVC foci （P〈0.05）. The high burden group had a higher LV end-diastolic dimension （EDD） and LVESD but lower LVEF than the other two groups （P〈0.05）. Female, older age, physical work, and history of PVCs had a significantly positive correlation with symptoms. Male, older age, physical work, and high burden were positive predictors of enlarged LVEDD, LVESD and higher serum NT-proBNP level, but lower LVEF. Seven-day dynamic ECG Holter monitor showed the true PVC burden on patients with PVCs. PVCs with a lower burden or origin from the LV papillary muscle and the fascicle were relatively benign, while PVCs with a higher burden or origin from the tricuspid annulus may lead to cardiac dysfunction.

HGF percutaneous endocardial injection induces cardiomyocyte proliferation and rescues cardiac function in pigs

Objective：To investigate the effect of cardiomyocyte proliferation induced by human hepatocyte growth factor（HGF）in pigs with chronic myocardial infarction（CMI）.Methods：A steerable,deflectable 7F catheter incorporating a 27-guage needle was advanced percutaneously to the left ventricular myocardium of 18 pigs with CMI.Pigs were randomized（1：1：1）to receive adenoviral vector HGF（total dose,1×10^10 genome copies）,which was administered as five injections into the infarcted myocardium（total,1.0 mL）,or saline,or Ad-null（control groups）.Injections were guided by Ensite NavX left ventricular electroanatomical mapping.HGF and cyclin proteins were detected by western blot and immunoprecipitation analysis.Histological and immunohistochemical analysis determined proliferating cardiomyocytes.Myocardial perfusion and cardiac function were estimated by Gated-Single Photon Emission Computed Tomography（G-SPECT）.Results：Western blot analyses showed that HGF were predominantly expressed in the infarct core and border in the myocardium of the infarcted heart.G-SPECT analysis indicated that the HGF group had better cardiac function and myocardial perfusion four weeks after the injection of Ad-HGF than before the injection of Ad-HGF.After treatment there were more proliferating cardiomyocytes in the HGF group compared to either of the control groups.Furthermore,the HGF group myocardial samples expressed higher levels of p-Akt,cyclin A,cyclin E,cyclin D1,cdk2,cdk4 than those in the control groups.Conclusion：The over-expression of HGF activates pro-survival pathways,induces cardiomyocyte proliferation,and improves the perfusion and function of the porcine CMI heart.

Pediatric restrictive cardiomyopathy due to a heterozygous mutation of the TNNI3 gene

Pediatric restrictive cardiomyopathy is rare and most commonly idiopathic in origin. Here, we applied a candi- date gene approach and identified a missense mutation in the cardiac troponin I gene in a 12-year-old Chinese girl with restrictive cardiomyopathy. This study indicates that mutation in sarcomere protein genes may play an im- portant role in idiopathic pediatric restrictive cardiomyopathy.

Resveratrol inhibits angiotensin II-induced ERK1/2 activation by downregulating quinone reductase 2 in rat vascular smooth muscle cells

Our previous studies showed that resveratrol could inhibit the proliferation of vascular smooth muscle cells （VSMCs） and repress mRNA and protein expression of quinone reductase 2 （NQO2）. This study further explored the potential mechanisms whereby resveratrol inhibits the proliferation of rat VSMCs. Lentiviral vectors that incorporated NQO2 small interfering RNA （siRNA） were constructed and transduced into rat VSMCs. The cell proliferation was detected using the bromodeoxyuridine （BrdU） assay. Cultured rat VSMCs were stimulated with angiotensin II and the level of reactive oxygen species （ROS） was measured using a ROS assay kit. A realtime quantitative PCR was used to detect NQO2 mRNA levels. Extracellular signal-regulated kinase （ERK1/2） and NQO2 protein expression were determined by Western blotting analysis. The inhibitory effect of resveratrol （10 and 50 μmol/L） on the proliferation of rat VSMCs in the NQO2 siRNA group was significantly weaker than that in the normal and scrambled siRNA group （P 〈 0.01）. The ROS level in the NQO2 siRNA and resveratrol （50 μmol/L） treatment groups were lower than that in the normal and scrambled siRNA groups （P 〈 0.01 in both）. Compared with the normal and scrambled siRNA group, the phosphorylation of ERK1/2 was significantly decreased in the NQO2 siRNA and resveratrol （50 μmol/L） treatment group （P 〈 0.01 in both）. In conclusion, high concentration of resveratrol inhibits angiotensin II-induced ERK1/2 phosphorylation and subsequent proliferation by down-regulation of NQO2 in cultured rat VSMCs.

Activation of calcium-sensing receptors is associated with apoptosis in a model of simulated cardiomyocytes ischemia/reperfusion

Objective： Calcium-sensing receptors （CaSRs） are G-protein coupled receptors which maintain systemic calcium homeostasis and participate in hormone secretion, activation of ion channels, cell apoptosis, proliferation, and differentiation. Previous studies have shown that CaSRs induce apoptosis in isolated adult rat heart and in normal neonatal rat cardiomyocytes by G-protein-PLC-IP3 signaling transduction. However, little knowledge is presently available concerning the role of CaSRs in the apoptosis induced by ischemia and reperfusion in neonatal cardiomyocytes. Methods： Primary neonatal rat ventricular cardiomyocytes were incubated in ischemiamimetic solution for 2 h, and then re-incubated in normal culture medium for 24 h to establish a model of simu- lated ischemia/reperfusion （I/R）. Cardiomyocyte apoptosis was detected by terminal deoxynucleotidyl transferase- mediated dUTP nick end labeling （TUNEL）. The expression of CaSRs mRNA was detected by real-time reverse transcription polymerase chain reaction （RT-PCR）. In addition, the expressions of caspase-3 and Bcl-2 were analyzed by western blot. Results： The simulated I/R enhanced the expression of CaSRs and cardiomyocyte apoptosis. GdCl3, a specific activator of CaSRs, further increased the expression of CaSRs and cardiomyocyte apoptosis, along with up-regulation of caspase-3 and down-regulation of Bcl-2. Conclusion： CaSRs are associated with UR injury and apoptosis in neonatal rat ventricular cardiomyocytes via suppressing Bcl-2 and promoting caspase-3 expression.

Effect of ecdysterone on heteroptopic heart transplantation in rats

Objective： To investigate the protective effects of ecdysterone（EDS） on the allograft heart transplant model of rats. Methods： Fifty healthy Sprayue-Dawley（SD） rats were divided into donors and recipients randomly. Hearts were harvested and placed heterotopically into allogenic recipients. All animals were divided into three groups： sham-operation group（only opening and closing the abdomen, n=l 0）, EDS group（injected intraperitoneally with 20 mg/（kg · day） of EDS, n = 10）, and control group （injected intraperitoneally with normal saline, n = 10）. The pathological changes of myocardial tissue were analyzed by light microscopy and transmission electron microscopy and the levels of myocardial enzymes（GOT, LDH, CPK）, SOD, ET-1, NO, MDA in serum were measured. Tissue samples underwent the detection ofapoptotic cell death by in situ terminal deoxyribonucleotide transferase-mediated dUTP nick end labeling for apoptotic index（M） and also by immunohistochemistry method to study the expressions of Bcl-2 and Bax. Results： Pathological examination and transmission electron microscope observation showed greater myocardium damage in the control group. EDS group showed a decrease in the amount of myocardial enzymes, MDA, ET-1 and an increase in the levels of SOD, NO, compared to the control group. The A1 of EDS group became lower than that of control group, meanwhile the EDS group increased the expression of Bcl-2 and decreased the expression of Bax. Conclusion： EDS has protective effects on heteroptopic heart transplantation, which provides a new idea for myocardial protection in heart transplantation. However, the mechanism of its protective effect needs further research.

Assessment of atrial electromechanical interval using echocardiography after catheter ablation in patients with persistent atrial fibrillation

We sought to investigate variation of atrial electromechanical interval after catheter ablation procedure in patients with persistent atrial fibrillation using pulse Doppler（PW） and pulse tissue Doppler imaging（PW-TDI）.A total of 25 consecutive in-patients with persistent atrial fibrillation,who restored sinus rhythm after ablation procedure,were recruited in our cardiac center.Echocardiography was performed on each patient at 2 hours,1 day,5 days,1 month and 3 months after the ablation therapy,and atrial electromechanical delay was measured simultaneously by PW and PW-TDI.There was no significant difference between PW and TDI in measuring atrial electromechanical delay.However,at postoperative 2 hours,peak A detection rates were mathematically but nonsignificantly greater by PWTDI than by PW.Second,there was a significant decreasing trend in atrial electromechanical interval from postoperative 2 hours to 3 months,but only postoperative 2-hour atrial electromechanical interval was significantly greater than atrial electromechanical interval at other time.Lastly,patients without postoperative 2-hour atrial electromechanical interval had a significantly longer duration of atrial fibrillation as compared to those with postoperative 2-hour atrial electromechanical interval,by the PW or by PW-TDI,respectively.In patients with persistent atrial fibrillation,atrial electromechanical interval may decrease significantly within the first 24 hours after ablation but remain consistent later,and was significantly related to patients＇ duration of atrial fibrillation.Atrial electromechanical interval,as a potential predicted factor,is recommended to be measured by either PW or TDI after24 hours,when patients had recovered sinus rhythm by radiofrequency ablation.

Comparative study of effects of bone marrow cell vs. Ad_5-HGF administration via non-infarct-related artery injection in myocardial infarction in swine

Objective： To evaluate the effect of transplanting bone marrow-derived mesenchymal stem cells （BM-MSCs） or adenovirus5- hepatocyte growth factor（Ad5-HGF） via non-infarct-related artery injection in swine myocardial infarction models. Methods：BMMSCs were obtained from swine bone marrow and expanded in vitro to a purity of 〉50%. A myocardial infarction（MI） was created by ligating the distal left anterior descending artery in swine. Either BM-MSCs （5 × 10^6/ml） or Ad5-HGF （4 × 10^9 pfu） were transfused via the right coronary artery （non-infarcted artery） four weeks after MI. Gate-controled cardiac perfusion imaging was performed at the end of four and seven weeks after LAD ligation, to evaluate heart function and cardiac perfusion. Morphologic and histologic characteristics of the hearts were also studied. Results： （1）The gate-controlled cardiac perfusion imaging showed that the improvement in LVEF was greater in both treatment groups than in control group at the 4^th weeks. （2）In both treatment groups, capillary density was significantly higher than that of control group（P 〈 0.05）. Conclusion ：BM-MSCs or Ad5-HGF transplantation via non-infarcted artery administration can stimulate angiogenesis and improve heart function, but there was no difference in therapeutic efficacy between BM-MSCs and Ad5-HGF.

Adeno-associated virus mediated apoA-I and apoA-IMilano expression in skeletal muscular cells

Objective： To construct recombinant adeno-associated virus type 2（rAAV2） vectors encoding human apoA-I/apoA-lMilano protein, and explore an effective and safe method to prevent and treat the atherosclerotic diseases. Methods： Human apoA-I cDNA with a His-tag in the upward stream of cDNA sequence were obtained with RT-PCR and PCR, and human apoA-IMilano cDNA was prepared by QuikChange Site-Directed Mutagenesis Kit. After extracted rAAV vectors with a most economic and convenient method, the particle numbers of rAAV vectors were measured by Dot-blot, and the purity was assayed by SOS-Page. The expression efficiency of the apoA-I or apoA-IMilano in C2C12 infected by rAAV vectors were detected by ELISA method. Results： ApoA-I cDNA was gained by RT-PCR and a His-tag was added in the upward stream of apoA-I cDNA successfully. ApoA-I cDNA was mutanted to apoA-IMilano cDNA successfully by QuikChange Site-Directed Mutagenesis Kit. The both titres of the rAAV vectors of apoA-I and apoA-IMilano were about 2×10^14/L, and the result of SOS-Page showed that the purity of the rAAV vectors was satisfied. The expression level of apoA-I was （0.39±0.04） μg/ml and the apoA-IMilano was （0.31±0.03） μ/ml in the DMEM culture medium at the first 24h after transfection. Conclusion： The success of the rAAV vectors construction, purification and the expression of apoA-I and apoA-IMilano in C2C12 cells mediated by these vectors, makes possible to inject rAAVA and rAAVAM vectors into mice muscle, and rises a new hope on finding a new way to prevent and treat atherosclerotic diseases and cardiovascular disease.

Histomorphological observation in arterial remodeling following New Zealand rabbit auto-extremity artery transplantation

Objective： To investigate the histomorphological change in auto-extremity artery following transplantation. Methods： 50 New Zealand rabbits were randomly divided into 5 groups（postoperative 1 d, 3 d, 7 d, 14 d, 56 d, n = 10）. Femoral artery was harvested and end-to-side anastomosed with carotid in order to build the auto-extremity arterial graft animal model. On the postoperative 1^st, 35^nd, 7^th, 14th and 56^th days, grafts for morphometric analysis under the Image analysis system were obtained; and electron microscope was scanned to observe endothelial cells. In addition, Immunostaining of sections were performed with the mouse monoclonal antibody of the a -smooth muscle isoform of actin and proliferating cell nuclear antigen antibody. Results： Overall patency rate for all conduits was 86%.The intimal hyperplasia was first observed in the 7^th day group, and continued to increase in the 56^th day group（183.21 ± 111.74） μ m, P 〈 0.01. Additionally, the luminal narrowed（32.43 ± 18.28）% in the 56^th day group. Smooth muscle cells were the mainly hyperplastic components. The most active proliferation of cells was detected in the 14^th day group, where the extracellular matrix gradually deposited in the intima. Conclusion： Moderate intimal hyperplasia occurred in arterial conduits and vascular structure experienced constrictive remodeling after auto-transplantation.

The V264M polymorphism of tissue factor pathway inhibitor gene in patients with acute coronary syndrome

Objective： To investigate V264M polymorphism of tissue factor pathway inhibitor （TFPI） in patients with acute coronary syndrome （ACS） in Chinese. Methods ： The genotypes of V264M were detected by polymerase chain reaction （PCR） and restriction fragment length polymorphism （PCR-RFLP） in 136 patients with ACS and 106 healthy controls with their plasmal f-TFPI tested by enzyme linked immunosorbent assay （ELISA）. Results： Two genotypes were found in V264M： GG and GA. The distribution frequencies of alleles and genotypes were in accordance with those predicted by Hardy Weinberg equilibrium in the present study （χ2 = 0.437, P 〉 0.05）. Plasma f-TFPI level was lower in A allele bearer than that in non-A allele carriers and higher in ACS than control subjects （P〈0.05）. No relationship was found between ACS and V264M polymorphism （P〉0.05）. Conclusion： The V264M polymorphism may have an impact on the plasma level of free TFPI（f-TFPI）, but it has no relationship with ACS.