The formation of the right and left heart ventricles from the ventricular portion of the heart tube in embryogenesis

It has been generally assumed that the initial rudiment of the heart ventricle is divided by the longitudinal interventricular septum into the right and left ventricles. This paper presents evidence for the hypothesis that the right and the left ventricles are produced during normal development from different sequentially located segments of the cardiac tube. These segments yielding rudiments of the right and left ventricles could be detected even during early embryogenesis. This hypothesis requires a new explanation for the process of the formation of two separate outlets from the heart ventricles.     

大鼠不同心肌肥厚模型左心室基因表达谱变化的比较

为了解心肌肥厚时基因表达谱的变化规律,本实验复制了三种大鼠心肌肥厚模型：肾上腹主动脉缩窄(suprarenal abdominal aortic stenosis,SRS)、动静脉瘘(arterial-vein fistula,AVF)和去甲。肾上腺素持续静脉输注(jugular vein infusion of norepinephrine,NEi),并应用组织化学方法和超声心动术检测大鼠心脏结构和功能指标,应用cDNA基因芯片技术检测心脏基因表达水平的变化。SRS和NEi引起大鼠向心性心肌肥厚,AVF引起大鼠离心性心肌肥厚,其中NEi大鼠心肌纤维化明显。对不同心肌肥厚模型间大鼠左心室基因表达谱的变化进行两两比较。结果显示,有部分基因在不同模型中表达水平均发生变化,其中多数基因在两种模型中表达水平改变的方向相同,也有少部分基因在两种模型中表达水平改变方向相反。综合比较三种心肌肥厚模型的基因表达谱,各种模型都有特异的基因表达变化,但是有19个基因在三种心肌肥厚模型中表达水平均发生改变。研究结果有可能成为心肌肥厚的标志性基因或治疗靶点,为心肌肥厚发生机制的深入研究提供了新的线索。     

Culture and characterization of fetal human atrial and ventricular cardiac muscle cells

Summary Atrial and ventricular cardiac muscle cells isolated from 14- to 18-wk old fetal human hearts were grown in culture and characterized. Once established in culture the flattened cells contracted spontaneously and possessed differentiated ultrastructural characteristics including organized sarcomeres, intercalated discs, and transverse tubules with couplings. Atrial granules were present in the cultured atrial cells. Some cultured ventricular myocytes also contained electron-dense granules associated with Golgi cisternae, which were similar in size and appearance to atrial granules. The cultured ventricular myocytes divided and expressed the genes for thymidine kinase, histone H4, myosin heavy chain, muscle-specific creatine kinase, atrial natriuretic factor, and insulin-like growth factor II. These results establish that differentiated fetal human heart muscle cells can be cultured in sufficient quantities for biochemical, molecular, and morphological analyses. This work was supported by a postdoctoral fellowship from the American Heart Association, Louisiana Affiliate (JBD) and the National Institutes of Health, Bethesda, MD (HL-35632) (WCC).     

大鼠成长期左心室基因表达谱的变化

为观察大鼠发育成熟过程中心脏生长与其基因表达谱变化的关系 ,应用超声心动术检测 8、10、12周龄Wistar大鼠的心脏结构和功能指标 ,应用cDNA基因芯片技术观察心脏基因表达水平的变化。大鼠从 8周龄生长至12周龄 ,体重增加约 45 7% ( 2 87± 13 gvs 197± 10g) ,前 2周和后 2周增加幅度相近。心脏左心室重量和室壁厚度分别增加约 2 7 7% ( 0 60± 0 0 3 gvs 0 47± 0 0 2 g)和 2 3 6% ( 2 0 4± 0 0 4mmvs 1 65± 0 13mm) ,前 2周增加幅度明显大于后 2周。基因表达谱的改变涉及细胞结构、代谢、氧化应激及信号转导等多方面的基因。 10周龄和 8周龄大鼠比较 ,变化的基因多数上调 ;12周龄和 10周龄大鼠比较 ,基因表达谱基本又返转至 8周龄水平。结果表明 ,大鼠在成长期的 4周内 ( 8- 12周龄 ) ,左心室基因表达谱发生的变化适应生理性心肌生长需要     

The effect of disease on human cardiac protein expression profiles in paired samples from right and left ventricles

Background

Cardiac diseases (e.g. coronary and valve) are associated with ventricular cellular remodeling. However, ventricular biopsies from left and right ventricles from patients with different pathologies are rare and thus little is known about disease-induced cellular remodeling in both sides of the heart and between different diseases. We hypothesized that the protein expression profiles between right and left ventricles of patients with aortic valve stenosis (AVS) and patients with coronary artery disease (CAD) are different and that the protein profile is different between the two diseases. Left and right ventricular biopsies were collected from patients with either CAD or AVS. The biopsies were processed for proteomic analysis using isobaric tandem mass tagging and analyzed by reverse phase nano-LC-MS/MS. Western blot for selected proteins showed strong correlation with proteomic analysis.

Results

Proteomic analysis between ventricles of the same disease (intra-disease) and between ventricles of different diseases (inter-disease) identified more than 500 proteins detected in all relevant ventricular biopsies. Comparison between ventricles and disease state was focused on proteins with relatively high fold (±1.2 fold difference) and significant (P < 0.05) differences. Intra-disease protein expression differences between left and right ventricles were largely structural for AVS patients and largely signaling/metabolism for CAD. Proteins commonly associated with hypertrophy were also different in the AVS group but with lower fold difference. Inter-disease differences between left ventricles of AVS and CAD were detected in 9 proteins. However, inter-disease differences between the right ventricles of CAD and AVS patients were associated with differences in 73 proteins. The majority of proteins which had a significant difference in one ventricle compared to the other pathology also had a similar trend in the adjacent ventricle.

Conclusions

This work demonstrates for the first time that left and right ventricles have a different proteome and that the difference is dependent on the type of disease. Inter-disease differential expression was more prominent for right ventricles. The finding that a protein change in one ventricle was often associated with a similar trend in the adjacent ventricle for a large number of proteins suggests cross-talk proteome remodeling between adjacent ventricles.     

慢性低氧对大鼠左右心室的功能及TRPC亚家族表达的影响

目的：探讨慢性低氧3周对大鼠左右心室的影响以及规范性瞬时感受器电位亚家族（TRPC）在慢性低氧诱导的右心室心肌肥厚中的表达。方法：将SD雄性大鼠48只随机分为对照组（CON组）和慢性低氧肺动脉高压模型组（CH组）（n=24）,CH组将大鼠置于连续的慢性低氧（10％±0．2％）环境饲养三周以诱导大鼠发生心肌肥厚。通过左、右心室插管法测定右心室内压（RVSP）、左心室内压（LVSP）、心率（HR）、平均体循环动脉压（mSAP）、左、右心室内压力最大上升速率（＋dp／dtmax）、最大下降速率（-dp／dkmax）、右心肥大指数（RVMI）、左心肥大指数（LVMI）;HE染色观察左、右心室心肌组织切片;通过SYBR Green荧光定量PCR法检测CON组、CH组大鼠的肥厚侧心室心肌组织编码TRPC 1／3／4／5／6／7的rnRNA表达;结合real-time RT-PCR结果对mRNA表达有显著变化的TRPC亚型通过免疫印迹法检测相应蛋白的表达。结果：与CON组相比：CH组的RVSP、RVMI、右心室±dp／dtmax显著增高（P〈0．01）,LVSP、左心室±dp／dmax无显著变化,LVMI显著降低（P〈0．01）;CH组右心室心肌细胞显著增粗（P〈0．01）,细胞内肌原纤维数量增多,心肌纤维排列紊乱,细胞核深染,形状不整;左心室心肌纤维无明显改变;CH组编码TRPCI的mRNA和蛋白显著增高（P〈0．05）,而编码其余TRPC亚型的mRNA无显著变化。结论：慢性低氧3周可特异性诱导sD大鼠产生右心室心肌肥厚,上调了编码右心室心肌细胞TRPCI通道蛋白的mRNA和蛋白的表达,TRPCI可能参与了心肌肥厚的发生发展。     

Comparisons of the release of vasodilator substances from left and right cardiac chambers of the isolated perfused rabbit heart: Implications for intraventricular thrombus formation

Prostacyclin (PgI₂) and endothelium-derived nitric oxide (EDNO) are produced by the arterial and venous endothelium. In addition to their vasodilator action on vascular smooth muscle, both act together to inhibit platelet aggregation and promote platelet disaggregation. EDNO also inhibits platelet adhesion to the endothelium. EDNO and PgI₂ have been shown to be released from the cultured endocardial cells. In this study, we examined the release of vasoactive substances from the intact endocardium by using isolated rabbit hearts perfused with physiological salt solution (95% O₂/5% CO₂, T = 37 °C). The right and left cardiac chambers were perfused through separate constant-flow perfusion loops (physiological salt solution, 8 ml min⁻¹). Effluent from left and right cardiac, separately, was bioassayed on canine coronary artery smooth muscle, which had been contracted with prostaglandin F_{2α_}(2 × 10⁻⁶ M) and no change in tension was exhibit. However, addition of calcium ionophore A23187 (10⁻⁶ M) to the cardiac chambers’ perfusion line induced vasodilation of the bioassay coronary ring, 61.4 ± 7.4% versus 70.49 ± 6.1% of initial prostaglandin F_2α contraction for the left and right cardiac chambers perfusate, respectively (mean ± SEM, n = 10, p > 0.05). Production of vasodilator was blocked totally in the left heart but, only partially blocked in the right heart by adding indomethacin (10⁻⁵ M) to the perfusate, respectively, 95.2 ± 2.2% versus 41.5 ± 4.8% (mean ± SEM, n = 10, p < 0.05). 6-Keto prostaglandin F_1α, measured in the endocardial superfusion effluent was also higher for the left cardiac chambers than for the right at the time of stimulation with the A23187, respectively, 25385.88 ± 5495 pg/ml (n = 8) versus 13,132.45 ± 1839.82 pg/ml (n = 8), (p < 0.05). These results showed that cyclooxygenase pathway plays major role in generating vasoactive substances for the left cardiac chamber endocardium; while it is not the main pathway for the right ventricular endocardium at which EDNO and PgI₂ could act together and potentiate their antithrombogenic activities in isolated perfused rabbit heart. This may be an explanation for the intraventricular thrombus mostly seen in left ventricle rather than in right ventricle as a complication of myocardial infarction.     

The role of matrix proteins in the control of nacreous layer deposition during pearl formation

To study the function of pearl oyster matrix proteins in nacreous layer biomineralization in vivo, we examined the deposition on pearl nuclei and the expression of matrix protein genes in the pearl sac during the early stage of pearl formation. We found that the process of pearl formation involves two consecutive stages: (i) irregular calcium carbonate (CaCO(3)) deposition on the bare nucleus and (ii) CaCO(3) deposition that becomes more and more regular until the mature nacreous layer has formed on the nucleus. The low-expression level of matrix proteins in the pearl sac during periods of irregular CaCO(3) deposition suggests that deposition may not be controlled by the organic matrix during this stage of the process. However, significant expression of matrix proteins in the pearl sac was detected by day 30-35 after implantation. On day 30, a thin layer of CaCO(3), which we believe was amorphous CaCO(3), covered large aragonites. By day 35, the nacreous layer had formed. The whole process is similar to that observed in shells, and the temporal expression of matrix protein genes indicated that their bioactivities were crucial for pearl development. Matrix proteins controlled the crystal phase, shape, size, nucleation and aggregation of CaCO(3) crystals.     

The right ventricle, outflow tract, and ventricular septum comprise a restricted expression domain within the secondary/anterior heart field

The vertebrate heart arises from the fusion of bilateral regions of anterior mesoderm to form a linear heart tube. Recent studies in mouse and chick have demonstrated that a second cardiac progenitor population, known as the anterior or secondary heart field, is progressively added to the heart at the time of cardiac looping. While it is clear that this second field contributes to the myocardium, its precise boundaries, other lineages derived from this population, and its contributions to the postnatal heart remain unclear. In this study, we used regulatory elements from the mouse mef2c gene to direct the expression of Cre recombinase exclusively in the anterior heart field and its derivatives in transgenic mice. By crossing these mice, termed mef2c-AHF-Cre, to Cre-dependent lacZ reporter mice, we generated a fate map of the embryonic, fetal, and postnatal heart. These studies show that the endothelial and myocardial components of the outflow tract, right ventricle, and ventricular septum are derivatives of mef2c-AHF-Cre expressing cells within the anterior heart field and its derivatives. These studies also show that the atria, epicardium, coronary vessels, and the majority of outflow tract smooth muscle are not derived from this anterior heart field population. Furthermore, a transgene marker specific for the anterior heart field is expressed in the common ventricular chamber in mef2c mutant mice, suggesting that the cardiac looping defect in these mice is not due to a failure in anterior heart field addition to the heart. Finally, the Cre transgenic mice described here will be a crucial tool for conditional gene inactivation exclusively in the anterior heart field and its derivatives.     

The in vitro chronotropic and inotropic effects of vasoactive intestinal peptide (VIP) on the atria and ventricular papillary muscle from Cynomolgus monkey heart

The in vitro chronotropic and inotropic effects of vasoactive intestinal peptide (VIP) and of isoproterenol, two agents known to stimulate cardiac adenylate cyclase were compared on the heart from Cynomolgus monkey using the spontaneously beating right atrium, the electrically stimulated left atrium, and the electrically-stimulated ventricular papillary muscle. VIP increased concentration-dependently the rate of beating of the right atrium as well as the contractility of both atria but its efficiency was lower than that of D,L-isoproterenol. VIP also stimulated concentration-dependently, and this time as efficiently as D,L-isoproterenol, the contractility of papillary muscle. These VIP effects were unaltered by the neuronal blocker tetrodotoxin. In addition, the moderate inhibition exerted by the beta-adrenergic blocker D,L-propranolol on VIP effects argued against the implication of beta-adrenergic receptors in VIP effects. These results indicate that VIP exerts a direct stimulatory influence on the rate and contractility of Cynomolgus monkey heart.     

Role of cardiac renin-angiotensin system in sarcoplasmic reticulum function and gene expression in the ischemic-reperfused heart

The aim of this study was to explore the possible participation of cardiac renin-angiotensin system (RAS) in the ischemia-reperfusion induced changes in heart function as well as Ca²⁺-handling activities and gene expression of cardiac sarcoplasmic reticulum (SR) proteins. The isolated rat hearts, treated for 10 min without and with 30 M captopril or 100 M losartan, were subjected to 30 min ischemia followed by reperfusion for 60 min and processed for the measurement of SR function and gene expression. Attenuated recovery of the left ventricular developed pressure (LVDP) upon reperfusion of the ischemic heart was accompanied by a marked reduction in SR Ca²⁺-pump ATPase, Ca²⁺-uptake and Ca²⁺-release activities. Northern blot analysis revealed that mRNA levels for SR Ca²⁺-handling proteins such as Ca²⁺-pump ATPase (SERCA2a), ryanodine receptor, calsequestrin and phospholamban were decreased in the ischemia-reperfused heart as compared with the non-ischemic control. Treatment with captopril improved the recovery of LVDP as well as SR Ca²⁺-pump ATPase and Ca²⁺-uptake activities in the postischemic hearts but had no effect on changes in Ca²⁺-release activity due to ischemic-reperfusion. Losartan neither affected the changes in contractile function nor modified alterations in SR Ca²⁺-handling activities. The ischemia-reperfusion induced decrease in mRNA levels for SR Ca²⁺-handling proteins were not affected by treatment with captopril or losartan. The results suggest that the improvement of cardiac function in the ischemic-reperfused heart by captopril is associated with the preservation of SR Ca²⁺-pump activities; however, it is unlikely that this action of captopril is mediated through the modification of cardiac RAS. Furthermore, cardiac RAS does not appear to contribute towards the ischemia-reperfusion induced changes in gene expression for SR Ca²⁺-handling proteins.     

The end effector of circadian heart rate variation: the sinoatrial node pacemaker cell

Cardiovascular function is regulated by the rhythmicity of circadian, infradian and ultradian clocks. Specific time scales of different cell types drive their functions: circadian gene regulation at hours scale, activation-inactivation cycles of ion channels at millisecond scales, the heart''s beating rate at hundreds of millisecond scales, and low frequency autonomic signaling at cycles of tens of seconds. Heart rate and rhythm are modulated by a hierarchical clock system: autonomic signaling from the brain releases neurotransmitters from the vagus and sympathetic nerves to the heart’s pacemaker cells and activate receptors on the cell. These receptors activating ultradian clock functions embedded within pacemaker cells include sarcoplasmic reticulum rhythmic spontaneous Ca²⁺ cycling, rhythmic ion channel current activation and inactivation, and rhythmic oscillatory mitochondria ATP production. Here we summarize the evidence that intrinsic pacemaker cell mechanisms are the end effector of the hierarchical brain-heart circadian clock system. [BMB Reports 2015; 48(12): 677-684]     

The expression of histone 2A in onion (Allium cepa) during the onset of dormancy, storage and emergence from dormancy

The tissue-specific and developmental expression of histone 2A was studied in onion ( Allium cepa 'Robusta'), using northern blots. Histone 2A expression was enriched in basal tissues, particularly in the inner, meristematically active parts of bulbs. The expression was assessed during a time course of bulb development, dormancy onset and post-harvest sprouting in field-grown material. During bulb development histone 2A expression in the inner bulb declined rapidly during bulb ripening, reaching a minimum with the onset of dormancy. During post-harvest storage, expression increased slowly, reaching a peak in the spring, coinciding with the first observed sprout emergence. It was concluded that in onion, as in other plant systems, histone 2A expression is linked to cell division and dormancy level, the peak in expression during post-harvest storage indicating the time of dormancy breakage. In cultivars where post-harvest sprouting occurred much earlier or much later than in 'Robusta', this expression peak occurred at about the same time of year, regardless of sprouting time. It was concluded that differences in storage longevity between cultivars were not due to differing times of dormancy breakage. Factors controlling the rate of sprout emergence post-dormancy are likely to be major determinants of storage capacity.     

LDL受体基因内含子15结构分析及其在家族性高胆固醇血症基因诊断中的应用

为了解人类ＬＤＬ受体基因内含子１５的遗传背景,利用长链ＰＣＲ和锚定ＰＣＲ分离了ＬＤＬ受体基因外显子１５－内含子１５－外显子１６和内含子１５的３‘末端片段。利用Ｄｙｎａｌｂｅａｄｓ固相单链分离ＰＣＲ产物直接测序法测定了内含子１５ ３’末端１２２２个碱基序列。序列显示：３‘末端含有由１６个碱基组成的典型３’末端剪接位点;３‘端上游第３１个碱基处含有经典分支位点,除了经典分支位点外,在３’末端上游第２０     

The impact of confounders on the test performance of natriuretic peptides for cardiac dysfunction in subjects aged 80 and older

The hypothesis that natriuretic peptides could be used to identify ‘pancardiac’ damage has been proposed. However, multiple factors are known to influence circulating levels of natriuretic peptides, especially in the very old. Therefore, the impact of confounders on the association between natriuretic peptide levels and cardiac dysfunction was further explored in subjects aged 80 and older. A diagnostic cross-sectional study embedded within the BELFRAIL study (n = 567) was performed. Baseline BNP and NT-proBNP levels were measured and echocardiograms were performed at the subject's home. Cardiac dysfunction was defined as systolic dysfunction, valvular heart disease or isolated severe diastolic dysfunction. Several functional and structural echocardiographic parameters were independently related to circulating levels of natriuretic peptides. Cystatin C, BMI, β blockers, diabetes, heart frequency, usCRP, age and sex were identified as confounders. The prevalence of cardiac dysfunction was 17.1% in the subjects without and 30.8% in the subjects with chronic atrial fibrillation (CAF) or pacemaker (PM). Only in subjects with CAF or PM the C statistic for cardiac dysfunction improved after correcting for confounders. The post-test probability for a negative test (PTP−) ranged from 3.7% to 12.2% and the PTP+ ranged from 21.9% to 62.2% in different strata of confounders. According to these data adjusting for identified confounders does not improve the diagnostic accuracy of the natriuretic peptides for cardiac dysfunction, except in subjects with CAF or PM. Stratifying for individual confounders showed that different cut-off values could be used to optimize the diagnostic characteristics of natriuretic peptides.