心房颤动患者心房肌浆网 Ca^2＋—ATP酶基因mRNA表达变化的研究

目的 研究心房颤动（房颤）患者Ca^2 调节－肌浆网Ca2 ATP酶mRNA表达的改变,探讨房颤时心肌细胞浆Ca2 超负荷的原因及其在房颤发生和维持中的作用。方法 38例风心病二尖瓣狭窄接受外科手术者,手术时取右心房及右心耳各约100mg,通过闻转录－聚合酶链反应技术,以GAPDH为内参照,测量肌浆网Ca^2 -ATP酶mRNA的变化。结果 房颤者肌浆网Ca2 -ATP酶mRNA较窦性心律者不调,而且随房颤持续时间的延长下调越明显,心房不同部位无差别,结论 房颤患者Ca2 -ATP酶mRNA下调,说明肌浆网Ca2 -ATP酶与房颤的发生与维持有关。     

压力超负荷下大鼠心肌细胞核钙调节系统的变化

目的：通过腹主动脉缩窄（abdominal aortic coaretation，AAC）心肌肥厚大鼠模型制备、差速离心提纯心肌细胞核、酶学方法测定Ca^2＋-ATPase活性、^45Ca^2＋同位素法测定核钙摄取和^3H放射配基受体分析心肌细胞核膜IP3R和RyR的动力学特性，初步揭示压力超负荷心肌肥厚大鼠心肌细胞核钙转导异常的环节。结果发现：AAC术后4周大鼠心肌显著肥厚，伴有明显的血流动力学异常，与对照组比较，AAC大鼠心肌细胞核Ca^2＋-ATPase活性减少51．93％（P〈0．001），但核^45Ca^2＋摄入量（核外[Ca^2＋]浓度为800-1600nmol／L时）明显增加（P〈0．05）；AAC大鼠心肌细胞核IP3R的Bmax和Kd与对照组比较分别增加1．217和2．149倍（P〈0．01），其细胞核RyR的最大结合（Bmax）较对照组减少57．8％（P〈0．001），解离常数（Kd）较对照组降低54．4％（P〈0．05）。结论为心肌细胞核Ca^2＋转运系统发生改变（Ca^2＋．ATPase活性减少、核^45Ca^2＋摄取增加、IP3R密度上调和亲和力降低，而细胞核RyR密度下调而亲和力增加），可能参与压力超负荷心肌肥厚的发生过程。     

慢性心房颤动患者心房肌浆网钙离子ATP酶及罗纳丹受体mRNA表达变化的研究

研究慢性心房颤动 (简称房颤 )患者Ca2 + 调节蛋白 肌浆网Ca2 + ATP酶及罗纳丹受体 (RyR)mRNA表达的改变 ,探讨房颤时心房肌细胞钙超载的原因及其在房颤发生和维持中的作用。选择 2 0例风湿性心脏病 (以二尖瓣狭窄为主 )接受瓣膜置换术者 ,于术中插管前取右心耳组织约 10 0mg ,采用逆转录 聚合酶链式反应技术 ,测定肌浆网Ca2 + ATP酶及RyR2 mRNA的变化。结果 :房颤者肌浆网Ca2 + ATP酶及RyR2 mRNA水平较窦性心律者明显下调 (分别为 0 .85 4± 0 .2 0 7vs 1.832± 0 .379,P <0 .0 0 1;1.4 12± 0 .319vs 2 .2 5 0± 0 .4 6 8,P <0 .0 5 ) ,且与临床血流动力学参数及性别、年龄无显著相关性。结论 :房颤患者肌浆网Ca2 + ATP酶及RyR2 mRNA表达水平下调 ,表明心房肌浆网钙离子调节蛋白可能参与房颤的发生或维持     

心肌细胞核兰尼碱受体在大鼠压力超负荷心肌肥厚发生中的作用

目的：探讨大鼠心肌细胞核上兰尼碱受体（ryanodine receptor,RyR)在心肌肥厚发生中的作用和意义，以及蛋白激酶A（PKA），钙调素（CaM)，佛波酯（PMA）和核外[Ca^2 ]对其影响，方法：制备腹主动脉缩窄大鼠心肌肥厚模型，差速离心和密度梯度离心提纯心肌细胞核，3H放射配基受体分析心肌细胞核膜RyR的动力学特性。结果：腹主动脉缩窄术后4周大鼠心肌显著肥厚，伴有明显的血流动力学异常，其细胞核RyR的最大结合（Bmax)较对照组减少57．8％（P＜0．001），离解常数（Kd)较对照组降低54．4％（P＜0．05），PKA使对照组细胞核RyR与3H兰尼碱的结合增加20．6％（P＜0．05），而对心肌肥厚组无显著作用，Ca^2 /CaM不影响其结合，而CaM抑制剂和内源性激活蛋白激酶C（PKC）则抑制其结合（P＜0．05），在核外[Ca^2 ]为10^-8-10^-4mol/L范围时，细胞核RyR与3H兰尼碱的结合呈先升高后降低趋势，在核外[Ca^2 ]为10^-6mol/L时达最大结合，结论：心肌细胞核上受磷酸化调节的RyR，压力超负荷心肌肥厚发生时，该受体密度下调而亲和力增加。     

心房颤动患者心房肌浆网Ca~(2 )-ATP酶基因mRNA表达变化的研究

目的　研究心房颤动 (房颤 )患者Ca2 调节基因 -肌浆网Ca2 ATP酶mRNA表达的改变 ,探讨房颤时心肌细胞浆Ca2 超负荷的原因及其在房颤发生和维持中的作用。方法　 38例风心病二尖瓣狭窄接受外科手术者 ,手术时取右心房及右心耳各约 10 0mg,通过逆转录 -聚合酶链反应技术 ,以GAPDH为内参照 ,测量肌浆网Ca2 ATP酶mRNA的变化。结果　房颤者肌浆网Ca2 ATP酶mRNA较窦性心律者下调 ,而且随房颤持续时间的延长下调越明显 ,心房不同部位无差别。结论　房颤患者Ca2 ATP酶mRNA下调 ,说明肌浆网Ca2 ATP酶与房颤的发生或维持有关     

应用RNA阵列技术检测自发性高血压大鼠肌浆网钙释放通道基因表达变化

目的 探讨肌浆网Ca2 释放通道在原发性高血压发病机制中的变化特点。方法 提取2、4、6、8、10、12周龄各组雄性自发性高血压大鼠(spontaneously hypertensive rats,SHR)和正常血压大鼠(Wistar-kyoto rats,WKY)心室肌、血管平滑肌、肝脏和肾脏组织的总RNA,共294个样品,利用高通量RNA阵列技术检测肌浆网兰尼碱受体2(ryanodine receptor,RyR2)和1,4,5-三磷酸肌醇受体1(inositol 1,4,5-triphosphate receptors,IP3R1)在不同周龄SHR中mRNA的表达谱改变。结果 与同周龄WKY相比较,SHR在6、8、10、12周龄血压出现显著性升高(P均<0.01),10、12周龄心室肌重量/体重比出现显著增加(P均<0.01),心肌中RyR2基因表达在4、6、8、10、12周龄出现显著性升高(P<0.05或P<0.01),IP3R1基因表达在6、8、10、12周龄出现显著性升高(P<0.05或P<0.01)。血管平滑肌组织中RyR2基因表达在4、6、8、10、12周龄出现显著性升高(P<0.05),IP3R1基因表达在4、6、8、10、12周龄出现显著性升高(P<0.05或P<0.01)。肝脏和肾脏组织中未见上述基因的明显表达。结论 肌浆网Ca2 释放通道受体蛋白RyR2和IP3R1 mRNA表达变化是实验性高血压发生和发展过程中重要的分子生物学机制。     

Ryanodine受体在心血管疾病中的研究进展

Ryanodine受体（RyR）作为肌浆网/内质网的钙释放通道,在心肌兴奋－收缩偶联过程中具有重要作用。目前已有研究结果表明,RyR结构、功能的变化与某些心血管疾病密切相关,并证实某些药物可以作用于RyR,从而达到治疗的目的。     

超压力负荷诱导肥厚心肌的肌浆网钙摄取和释放的改变

目的探讨超压力负荷下左心室心肌肌浆网钙ATP酶、雷诺定受体2(ryanodine receptor2,RYR2)和三磷酸肌醇受体1(inositol1,4,5-trisphosphate receptor1,IP3R1)变化以及血管紧张素Ⅱ受体阻断药的影响。方法用腹主动脉缩窄法建立大鼠超压力负荷模型。检测心肌肌浆网钙ATP酶活性、Ca2 最大摄取速率、Ca2 最大摄取量、3H-雷诺定与RYR2最大结合量和RYR2受体密度。用免疫印迹法检测心肌肌浆网钙ATP酶2a(SERCA2a)蛋白表达;用反转录-聚合酶链反应检测心肌RYR2和IP3R1的mRNA表达。结果高压力负荷下左心室心肌呈典型的肥厚心肌的形态改变。手术组左心室心肌内浆网钙ATP酶活性、Ca2 最大摄取速度、Ca2 摄取量、RYR2最大结合量、RYR2的mRNA表达[吸光度/磷酸甘油醛脱氢酶]、IP3R1mRNA表达[吸光度/磷酸甘油醛脱氢酶]均低于假手术组(差异有统计学意义,P<0.01,n=12),缬沙坦组高于手术组及PD123319组(P<0.05),手术组与PD123319组间差异无统计学意义(P>0.05,n=12)。结论超压力负荷诱导的肥厚心肌组织钙调节能力明显下降,但缬沙坦可改善肥厚心肌组织的钙调节能力。     

Ryanodine受体在心力衰竭和心律失常中的作用

Ryanodine受体（ryanodine receptor,RyR）是肌浆网膜上的钙释放通道。钙释放失调在心力衰竭发展过程中具有关键作用。此外,RyR基因突变会导致肌浆网钙渗漏触发心律失常。因此,针对RyR已成为心力衰竭和心律失常治疗的一个新的策略。     

肌浆网钙泄漏在心脏功能不全中的作用

同步肌浆网Ca2+释放以外的Ca2+释放即肌浆网Ca2+泄漏（Ca2+ leak），包括Ca2+火花（Ca2+ spark）、自发性Ca2+波（spontaneous Ca2+ wave）和其他微小Ca2+释放等。心肌细胞肌浆网Ca2+泄露主要是由II型兰尼碱受体（ryanodine receptor 2,RyR2）介导的，它可以通过减少肌浆网Ca2+的有效释放导致心脏收缩功能障碍；通过升高舒张期胞浆Ca2+引发心脏舒张功能不全，诱发心律失常。此外，肌浆网Ca2+泄露还可以引起因肌浆网Ca2+回摄增多消耗更多的ATP，导致心律失常、心力衰竭等心脏疾病的进一步恶化。     

Alterations in cardiac sarcoplasmic reticulum Ca2+ regulatory proteins in the atrial tissue of patients with chronic atrial fibrillation.

OBJECTIVES: Our purpose was to determine whether atrial fibrillation (AF) patients have alterations in sarcoplasmic reticulum (SR) Ca2+ regulatory proteins in the atrial myocardium. BACKGROUND: Clinically, AF is the most frequently encountered arrhythmia. Recent studies indicate that an inability to maintain intracellular Ca2+ homeostasis with a consequent increase in membrane-triggered activity could be the primary initiating factor in some circumstances, and that cytosolic Ca2+ abnormalities are an important mediator of sustained AF. METHODS: We measured the maximum number of [3H]ryanodine binding sites (Bmax) and the expression levels of ryanodine receptor (RyR) mRNA and calcium-adenosine triphosphatase (Ca2+-ATPase) mRNA in atrial myocardial tissue from 13 patients with AF due to mitral valvular disease (MVD) and 9 patients with normal sinus rhythm (NSR). RESULTS: In AF patients, 1) Bmax was significantly lower in each atrium (0.21+/-0.03 pmol/mg [right], 0.16+/-0.04 pmol/mg [left]) than in the right atrium (0.26+/-0.08 pmol/mg) of NSR patients; 2) Bmax was significantly lower in the left atrium than in the right atrium; 3) Bmax in the left atrium was significantly lower at higher levels of pulmonary capillary wedge pressure; 4) the expression level of RyR mRNA was significantly lower in both the left (1.24 x 10(-2)+/-1.28 x 10(-2)) and right (1.70 x 10(-2)+/-1.78 x 10(-2)) atrium than in the right atrium of NSR patients (6.11 x 10(-2)+/-2.79 x 10(-2)); and 5) the expression level of Ca2+-ATPase mRNA was significantly lower in both the left (5.67 x 10(-2)+/-4.01 x 10(-2)) and right (7.71 x 10(-2)+/-3.56 x 10(-2)) atrium than in the right atrium (12.60 x 10(-2)+/-3.92 x 10(-2)) of NSR patients. CONCLUSIONS: These results provide the first direct evidence of abnormalities in the Ca2+ regulatory proteins of the atrial myocardium in chronic AF patients. Conceivably, such abnormalities may be involved in the initiation and/or perpetuation of AF.     

Alterations in gene expression of proteins involved in the calcium handling in patients with atrial fibrillation

INTRODUCTION: Atrial fibrillation (AF) leads to a loss of atrial contraction within hours to days. During persistence of AF, cellular dedifferentiation and hypertrophy occur, eventually resulting in degenerative changes and cell death. Abnormalities in the calcium handling in response to tachycardia-induced intracellular calcium overload play a pivotal role in these processes. METHODS AND RESULTS: The purpose was to investigate the mRNA expression of proteins and ion channels influencing the calcium handling in patients with persistent AF. Right atrial appendages were obtained from 18 matched controls in sinus rhythm (group 1) and 18 patients with persistent AF undergoing elective cardiac surgery. Previous duration of AF was < or = 6 months in 9 (group 2) and > 6 months in 9 patients (group 3). In a single semiquantitative polymerase chain reaction, the mRNA of interest and of glyceraldehyde-3-phosphate dehydrogenase, were coamplified and separated by gel electrophoresis. L-type calcium channel alpha1 subunit mRNA content was inversely related to the duration of AF: -26% in group 2 compared to group 1 (P = 0.2), and -49% in group 3 compared to group 1 (P = 0.01). Inhibitory guanine nucleotide binding protein ialpha2 mRNA content was reduced in group 3 compared to group 1 (-30%, P = 0.01). Sarcoplasmic reticulum calcium ATPase, phospholamban and sodium-calcium exchanger mRNA contents were not affected by AF. CONCLUSIONS: AF-induced alterations in mRNA contents of proteins and ion channels involved in the calcium handling seem to occur in relation to the previous duration of AF. In the present patient population, these changes were significant only if AF lasted > 6 months.     

风湿性心脏病慢性心房颤动患者钙调蛋白的表达

目的探讨慢性心房颤动(简称房颤)患者的心房肌是否存在钙调蛋白(CaM)含量和mRNA表达的改变,同时比较左右房心肌CaM含量的差异。方法风湿性心脏瓣膜病患者在术中体外循环开始后立即取心房组织约100~200mg按照有无慢性房颤以及标本取材部位分组,采用WesternBlot和实时定量聚合酶链式反应(PCR)检测CaM蛋白含量和mRNA的表达变化。结果WesternBlot显示房颤组右、左房心肌较窦性心律组右房心肌增加了23%和36%(P<0.01),而且房颤组左房CaM蛋白含量较右房也有升高(P<0.05)。实时定量PCR显示房颤组右房和左房心肌分别较窦性心律组右房心肌增加了29.4%和34.4%(P<0.01)。直线相关分析显示房颤持续时间与CaM蛋白含量和mRNA表达量均明显相关,相关系数分别为0.6869和0.7206(P<0.01)。结论房颤时CaM蛋白含量和mRNA表达明显增加,其中CaM蛋白含量在左房增加更为明显,而且随着房颤时间的延长CaM蛋白含量和mRNA表达量也逐渐增多。     

心房颤动犬心房肌细胞2型理阿诺受体的分布和表达

目的探讨心房颤动(房颤)时心房肌细胞2型理阿诺受体表达和分布的改变。方法杂种犬10只,分为正常对照组和单纯房颤组,每组5只。单纯房颤组用起搏器进行房颤式快速起搏,起搏频率(500±20)次/min,正常对照组不植入起搏器。24周后取出心脏,用逆转录聚合酶链反应、免疫荧光染色技术检测犬心房肌细胞2型理阿诺受体在mRNA水平的表达和蛋白水平的表达和分布。结果与正常对照组比较,单纯房颤组犬2型理阿诺受体在mRNA和蛋白水平的表达明显低于正常对照组(P<0.05);在细胞质、细胞膜2型理阿诺受体分布均显著减少。结论房颤时心房肌细胞2型理阿诺受体表达下调,2型理阿诺受体可能不是心房肌细胞主要的钙信号调控的受体。     

Up-regulation of inositol 1, 4, 5-trisphosphate receptor expression in atrial tissue in patients with chronic atrial fibrillation

BACKGROUND: Abnormal intracellular Ca2+ homeostasis occurs in chronic atrial fibrillation(AF). The intracellular Ca2+ concentration is regulated by ryanodine and inositol 1,4,5-trisphosphate (IP3) receptors. Changes occur in ryanodine receptors in atrial tissue from patients in chronic AF. Whether AF patients have alterations in atrial IP3 receptors was investigated. METHODS: IP3 receptor expression was analyzed in the right atrial myocardium from 13 mitral valvular disease (MVD) patients with AF (MVD/AF), 5MVD patients with normal sinus rhythm(MVD/NSR), and 8 control patients with NSR(tissue obtained during coronary artery bypass surgery). Hemodynamic and echocardiographic data were obtained preoperatively, and an immunohistochemical study was performed on the atrial tissue. RESULTS: The relative expression level of IP3 receptor protein was significantly greater in MVD/AF (0.75 +/- 0.26) than in MVD/NSR (0.42 +/- 0.13, p < 0.01), and both were significantly above the control value (0.14 +/- 0.08). The relative expression level of IP3 receptor mRNA was significantly greater in MVD/AF(0.028 +/- 0.008) than in control subjects (0.015 +/- 0.004, p < 0.01), but MVD/AF patients did not differ from MVD/NSR (0.020 +/- 0.006) patients. The relative expression levels of IP3 receptor protein and mRNA were higher in patients with left atrial dimension > or = 40 mm, pulmonary capillary wedge pressure > or = 10 mmHg, and right atrial pressure > or = 5 mmHg. IP3 receptors were overexpressed in the cytosol and at the nuclear envelope of atrial myocytes in MVD. CONCLUSIONS: Since chronic mechanical overload of the atrial myocardium increases IP3 receptor expression, especially in patients with chronic AF, up-regulation of IP3 receptors may be important in modulating intracellular Ca2+ homeostasis and initiating and/or perpetuating AF.     

Selective induction of matrix metalloproteinases and tissue inhibitor of metalloproteinases in atrial and ventricular myocardium in patients with atrial fibrillation

Atrial fibrillation (AF) produces changes in atrial structure and extracellular matrix composition, which is regulated by matrix metalloproteinases (MMPs). Moreover, AF often occurs in the setting of congestive heart failure (CHF), which also affects MMPs. Whether changes in MMPs or the tissue inhibitors of metalloproteinases (TIMPs) within atrial and ventricular myocardium are differentially regulated with AF remains unclear. Myocardium from the walls of the right atrium, right ventricle, left atrium, and left ventricle was obtained from the explanted hearts of 43 patients with end-stage CHF. AF was present in 23 patients (duration 1 to 84 months). The remaining 20 patients served as non-AF controls. The groups were well matched clinically, but left atrial (LA) size was increased in the AF cohort (5.5 +/- 0.8 vs 4.9 +/- 0.7 cm, p <0.05). Myocardial collagen content and levels of MMP-1, -2, -8, -9, -13, and -14, and TIMP-1, -2, -3, and TIMP-4 were determined. With AF, collagen content was greater within the atrial myocardium but less in the ventricular myocardium. There were chamber-specific differences in MMPs and TIMPs with AF. For example, MMP-1 in the right atrium and MMP-9 in the left atrium were greater with AF. TIMP-3 levels were greater in the right ventricle, left atrium, and left ventricle. Although total LA collagen was positively correlated with AF duration (r = 0.49, p <0.03), there was an inverse relation between soluble collagen I and AF duration (n = 6, r = -0.84, p <0.04). In conclusion, AF is associated with chamber-specific alterations in myocardial collagen content and MMP and TIMP levels, indicative of differential remodeling and altered collagen metabolism. Differences in MMP and TIMP profiles may provide diagnostic and mechanistic insights into the pathogenesis of AF with CHF.