小鼠病毒性心肌损伤模型制作及cTnI基因扩增与测序分析

目的:分析心肌型肌钙蛋白(cTnI) mRNA在监测病毒性心肌损伤发生与发展过程中的价值。方 法:于BALB/c小鼠腹腔接种1×108TCID50柯萨奇病毒B3(CVB3)诱发心肌损伤,分别在CVB3感染后第3、6、9、 12、15、18和21天采集外周血后处死小鼠,留取鼠心脏作病理组织学检查,以逆转录 聚合酶链反应(RT PCR)分 析心肌和外周血中cTnI基因及测序分析扩增片段。结果:CVB3感染后,鼠心肌组织及循环血中cTnI mRNA均 表达增加,且与心肌细胞肿胀、炎性细胞浸润、核固缩及碎裂、变性、坏死、钙化等组织学改变相关。cTnI mRNA 基因扩增,心肌组织全数阳性;外周血阳性率在对照组及感染后的第3、6、9、12、15、18和21天分别为0、0、0、 16.7%、40%、71.4%、83.3%和87.5%。测序分析证实从心肌组织及外周血中扩增基因片段与原序列完全一致。 结论:病毒性心肌损伤时cTnI mRNA上调表达并释放入血,循环血cTnI mRNA为监测心肌损伤发生与发展的 灵敏标志物。     

病毒性心肌炎的快速检测心肌肌钙蛋白Ⅰ

目的 :探讨快速检测心肌肌钙蛋白 ( c Tn I)对病毒性心肌炎 ( VMC)的诊断价值。方法 :对 72例 VMC患者和 30例对照者进行 c Tn I和心肌酶谱检测分析。结果 :在诊断 VMC时 ,c T-n I敏感性和特异性都明显高于心肌酶谱 ( P <0 .0 0 1 )。结论 :c Tn I可作为诊断 VMC的重要指标     

Molecular insights from a novel cardiac troponin I mouse model of familial hypertrophic cardiomyopathy

Gene mutations in cardiac troponin I (cTnI) account for up to 5% of genotyped families with familial hypertrophic cardiomyopathy (FHC). Little is known about how cTnI mutations cause disease. Five lines of transgenic mice were generated which overexpress the human disease-causing cTnI gene mutation, Gly203Ser (designated cTnI-G203S), in a cardiac-specific manner. Mice were compared to transgenic mice that overexpress normal cTnI (cTnI-wt) and non-transgenic littermates (NTG). cTnI-G203S mice developed all the characteristic features of FHC by age 21 weeks. Left ventricular hypertrophy was observed on echocardiography (1.25+/-0.05 mm vs. 0.86+/-0.02 mm in cTnI-wt, P<0.01), associated with a significant 4-fold increase in RNA markers of hypertrophy, ANF and BNP. Myocyte hypertrophy, myofiber disarray and interstitial fibrosis were observed in cTnI-G203S mice. Expression of the cTnI-G203S mutation in neonatal cardiomyocytes resulted in a significant increase in myocyte volume, and reduced interactions with both troponins T and C. Ca2+ cycling was abnormal in adult cardiomyocytes extracted from cTnI-G203S mice, with a prolonged decay constant in Ca2+ transients and a reduced decay constant in response to caffeine treatment. Mice with the cTnI-G203S gene mutation develop all the phenotypic features of human FHC. The cTnI-G203S mutation disrupts interactions with partner proteins, and results in intracellular Ca2+ dysregulation early in life, suggesting a pathogenic role in development of FHC.     

Overexpression of calpastatin by gene transfer prevents troponin I degradation and ameliorates contractile dysfunction in rat hearts subjected to ischemia/reperfusion

Calpain is a Ca(2+)-activated neutral protease that supposedly plays a key role in myocardial dysfunction following ischemia/reperfusion, by degrading certain proteins involved in the contraction mechanism. It is possible that overexpression of calpastatin, an endogenous calpain inhibitor, lessens contractile dysfunction in the heart after reperfusion by preventing cardiac troponin I (TnI) degradation. This claim is tested by overexpression of human calpastatin (hCS) in rat hearts ex vivo using an adenovirus vector; the hearts were transplanted heterotopically into the abdomens of recipient rats to allow expression of hCS. On the fourth day after surgery, the hearts were excised and perfused in vitro to study their recovery from 30 min of global ischemia, which was followed by 60 min of reperfusion. The peak recovery of the left ventricular developed pressure (LVDP), and the values of its first derivative (max dP/dt, min dP/dt) in the hCS-overexpressed hearts were 88.9 +/- 4.8%, 90.8 +/- 9.2% and 106.4 +/- 9.8%, respectively; these values were all significantly greater than in the control hearts transfected with LacZ alone (51.4 +/- 6.9%, 52.6 +/- 8.1% and 54.7 +/- 6.6%, P < 0.05). In western blot analysis of ventricular myocardial samples (at 60-min reperfusion) using a monoclonal anti-TnI antibody, two bands corresponding to intact TnI (30 kDa) and TnI fragments (27 kDa) were distinguished. The fraction of 27-kDa TnI (percent of total TnI immunoreactivity) in hCS-overexpressed hearts was significantly less than the controls (5.7 +/- 2.7% vs. 18.1 +/- 3.2%, P < 0.05), implying a protective action of hCS against TnI degradation. These results suggest that adenovirus-mediated overexpression of hCS in the heart could be a novel biological means to minimize myocardial stunning by ischemia/reperfusion.     

心肌肌钙蛋白I在心脏移植术后恢复及排斥反应中的意义

目的对19例心脏移植受体术后早期及定期行心肌肌钙蛋白I(cardiactroponinI,cTnI)检测,探讨cTnI在心脏移植术后恢复及排斥反应中的作用。方法(1)对19例心脏移植受体术后1个月内每日行cTnI检测;(2)对存活的心脏移植受体每3个月或发现急性排斥反应时行cTnI检测。结果(1)19例心脏移植术后1个月内恢复顺利的患者其心肌cTnI的下降速度均较快,心脏移植后8天内均下降至10μg/L以下,20天内降至正常,而死亡5例患者中早期死亡的3例其cTnI在术后10天后仍维持在较高水平;(2)14例存活的心脏移植受体定期复查cTnI均正常,其中4例心肌活检病理确诊为Ⅱ级以上急性排斥反应患者,不论出现急性排斥反应的级别高低,其cTnI均未见升高。结论cTnI对心脏移植早期恢复评定具有重要意义,而与急性排斥反应无明显相关性。     

高敏C反应蛋白和肌钙蛋白I在心力衰竭患者血清中的变化

目的探讨血清高敏C反应蛋白（hsCRP）及肌钙蛋白I（cTnI）在心力衰竭患者中的变化及意义。方法46例（NYHA分级Ⅲ-Ⅳ级）心力衰竭患者，Ⅲ级组26例，Ⅳ级组20例，分别于清晨空腹和心功能改善至Ⅰ-Ⅱ级后采血清，测定hsCRP和cTnI。选取45例体检健康者作为对照组。结果心衰组hsCRP和cTnI均较对照组升高（P〈0．01）；心衰组中心功能Ⅳ级组与Ⅲ级组比较cTnI值升高（P〈0．01），而hsCRP无明显差异。心衰组随着心功能的改善hsCRP和cTnI明显下降，与治疗前比较差异具有统计学意义（P〈0．01）。另外，不同病因心衰组hsCRP和cTnI差异均无统计学意义。结论心衰时hsCRP和cTnI均升高，且随着心功能损害加剧而增高明显，心衰患者存在明显的炎性活动和心肌细胞损害，并与病情严重程度相关。提示hsCRP和cTnI可能是反映心力衰竭病情变化的两项指标。     

心肌肌钙蛋白I与冠心病远期心脏事件的关系探讨

目的　探讨冠心病患者血清心肌肌钙蛋白I(cTnI)水平与远期心脏事件的相关性。方法　测定 16 6例冠心病患者的血清cTnI、肌酸激酶同工酶 ,根据cTnI的值分为二组 ,根据临床资料、冠状动脉造影结果 ,随访患者远期心脏事件 ,分析cTnI与心脏事件的相关因素及它们的关系。结果　 16 6例患者中有 5 8例cTnI升高 ,4例肌酸激酶同工酶轻度升高 ,cTnI升高与心电图出现异常Q波、ST段改变关系有统计学意义 (P <0 0 5 ) ;cTnI升高组糖尿病患者数明显低于cTnI正常组 (P <0 0 5 ) ;15 9例近期存活者中 15 1例进行了远期随访 ,随访时间为 (2 6± 10 )个月 ,共有 2 7例患者发生心脏事件32例次 ,其发生与cTnI升高关系有统计学意义 (P <0 0 5 )。结论　血清cTnI是心肌损伤敏感而特异性的指标 ,是冠心病患者远期心脏事件的独立预测因子。     

Partial replacement of cardiac troponin I with a non-phosphorylatable mutant at serines 43/45 attenuates the contractile dysfunction associated with PKCepsilon phosphorylation

We have previously reported a transgenic mouse that over-expresses constitutively active PKCepsilon in the myocardium and exhibits a steady progression to heart failure. Associated with the decline in function was an increased phosphorylation of sarcomeric proteins including cardiac troponin I (cTnI). To determine whether PKCepsilon phosphorylation of cTnI is sufficient to induce cardiac maladaptation, we have generated a double transgenic mouse (DbTG) that expresses constitutively active PKCepsilon and cTnI harboring non-phosphorylatable mutations in the putative PKC phosphorylation sites (S43A, S45A). We compared the hemodynamic and biochemical properties of the hearts from the DbTG mice to the non-transgenic and single transgenic lines at both 3 and 12 months of age. While no significant differences in LV function were noted in 3-month groups, the depression of function in the PKCepsilon mice was attenuated in the double transgenic mice at 12 months. The improvement in cardiac function was correlated with decreased beta-myosin heavy chain and ANF mRNA expression in the 12m DbTG mice. The extent of cTnI phosphorylation was determined using a novel one-dimensional, non-equilibrium isoelectric focusing technique. At 3 months the migration of cTnI phospho-species was different in the PKCepsilon mice and to a lesser degree in the DbTG compared to all other groups. At 12 months additional phospho-species were observed in both the PKCepsilon and DbTG samples, along with an overall shift in the distribution of phospho-species in all groups due to age. These results suggest that phosphorylation of cTnI by PKCepsilon is associated with contractile dysfunction and partial replacement of serines 43/45 improves cardiac performance. Therefore, we conclude that phosphorylation of cTnI at Ser 43 and 45 may contribute to the progression of failure.     

乌司他丁对全身麻醉下行颈动脉内膜切除术患者血清心肌肌钙蛋白I的影响

目的探讨乌司他丁对全身麻醉下行颈动脉内膜切除术(CEA)患者术后血清心肌肌钙蛋白I(cTnI)的影响。方法将2011年1月—2012年3月40例症状性颈动脉重度狭窄,于全身麻醉下行单侧CEA的患者按照随机数字表法分为乌司他丁组和对照组,每组20例。乌司他丁组在麻醉诱导前,经静脉给予乌司他丁50万U,给予对照组等量等渗盐水。分别于术前、术后第1、2、3天检测患者血清cTnI的浓度。心肌损伤定义为cTnI峰浓度0.04μg/L。结果乌司他丁组术前及术后第1、2、3天血清cTnI水平分别为中位数(M)0.00(0.00~0.03)、0.07(0.00~1.45)、0.01(0.00~1.21)及0.05(0.00~0.89)μg/L;对照组分别为0.00(0.00~0.01)、0.00(0.00~1.42)、0.00(0.00~1.39)及0.00(0.00~1.24)μg/L。对照组6例(30%)与乌司他丁组11例(55%)患者术后第1天发生心肌损伤,组间差异无统计学意义(P0.05)。所有cTnI水平升高患者的cTnI高峰出现在术后第1天,但均未达到提示患者发生心肌梗死的水平(1.5μg/L)。结论乌司他丁不能降低全身麻醉下CEA患者术后的血清cTnI水平,对CEA患者是否具有心肌保护作用,需更多样本加以证实。     

老年充血性心力衰竭患者心功能与甲状腺激素的关系

目的 探讨血清N末端B型脑钠肽前体（NT-proBNP）和甲状腺激素的关系,以及在老年充血性心力衰竭患者治疗中的临床价值.方法 测定老年慢性充血性心力衰竭（CHF）患者不同心功能状态下血清NT-proBNP和甲状腺激素的水平.结果 CHF组与对照组比较三碘甲状腺原氨酸（T3）、游离三碘甲状腺原氨酸（FT3）水平降低,差异有统计学意义,且随心功能不全程度加重,T3、F-T3、甲状腺素（T4）、游离甲状腺素（FT4）水平依次降低,NT-proBNP水平依次升高,LVEF水平依次下降,差异有统计学意义（P＜0.01）.结论 监测血清甲状腺激素水平,对判断心衰程度、治疗及预后有一定临床价值.     

婴幼儿心内直视手术中监测血清肌钙蛋白I的临床价值

目的探讨先天性心脏病（CHD）患儿血清肌钙蛋白I（cTnI）在心内直视手术中的变化及临床意义。方法采用酶联免疫吸附法（ELISA）检测15例先天性心脏病患者cTnI在心内直视手术中的浓度变化。结果cTnI的浓度在主动脉开放即刻，主动脉开放后2、6、24h均较术前升高，差异有统计学意义（P〈0．05）。主动脉开放后再灌注2h左右出现一个明显的峰值，以后逐渐下降，无双峰，cTnI峰值浓度范围为0．83-7．41（4．20±0．93）μg／L。cTnI浓度随主动脉阻断时间增加而增高，其与主动脉阻断时间之问存在明显的相关性（y=5．008x＋22．327，r=0．8831，P=0．003）。结论cTnI的浓度可以作为判定先天性心脏病患儿心内直视手术中心肌损伤程度的重要指标，cTnI浓度升高越明显，提示术中心肌损伤程度越大。     

血清肌钙蛋白I、肌酸激酶同工酶-Ⅱ测定在肾衰患者中的作用

目的：观察慢性肾功能衰竭患者心肌肌钙蛋白、肌酸激酶同工酶一Ⅱ的异常变化,并分析其与预后的关系。方法：应用ACCESS2化学发光法检测慢性肾功能衰竭患者心肌肌钙蛋白、肌酸激酶同工酶一Ⅱ,彩色多普勒测定左室射血分数（EF）,同时对心肌肌钙蛋白升高患者进行APACHEⅡ评分。结果：48例患者血清肌钙蛋白I升高率为44．4％;APACHEⅡ评分在心肌肌钙蛋白升高患者中明显升高;血清肌钙蛋白I、肌酸激酶同工酶-Ⅱ同时升高患者,心衰发生率高。结论：慢性肾功能衰竭患者心肌损伤较为普遍且部分为亚临床损伤,需谨慎对待。     

不同类型冠状动脉病变介入治疗前后血清淀粉样物质A及肌钙蛋白I的变化

目的 :观察不同类型冠状动脉病变介入治疗前后血清淀粉样物质A(SAA)及心肌肌钙蛋白I(cTnI)的变化特点。方法 :选取接受冠状动脉介入治疗的患者 4 9例 ,按 1988年ACC/AHA专家组分类法 ,分为A、B、C三型 ,三型均于术中记录球囊扩张时间、球囊最大充盈压 (MIP)、扩张次数及造影剂用量 ,并于术前 ,术后 1、6、2 4、4 8h检测SAA、cTnI水平。结果 :A型病变组球囊扩张时间、MIP、扩张次数及造影剂用量均明显小于B、C型病变组 ,B型病变组球囊扩张时间、扩张次数及造影剂用量小于C型病变组。A型病变各时点SAA水平均高于术前且均小于同时点B、C两组水平 ;术后 2 4hA型病变组cTnI水平明显低于B、C型病变组。结论 :复杂病变患者介入治疗后SAA、cTnI水平升高明显 ,应考虑进一步给予药物辅助治疗改善预后     

Thyroid hormone and glucocorticoid regulation of receptor and target gene mRNAs in pituitary GH3 cells

We have examined the effects of triiodothyronine (T₃), in dose-response and time-course studies, on T₃ receptor (T₃R) and β and glucocorticoid receptor (GR) mRNAs in rate pituitary GH₃ cells, in parallel with T₃ actions on expression of the growth hormone (GH) target gene. Modulatory influences of dexamethasone (dex) on T₃ action were studied by treatment with dex before and during T₃ treatment. T₃ treatment (1–100 nM) for 24 h reduced T₃R mRNA, while the presence of dex (1 μM) enhanced the T₃ effect on T₃R mRNA and induced T₃ inhibition of T₃R β mRNA. Stimulatory effects of T₃ treatment on GH mRNA and release were seen in the face of inhibition of T₃R mRNAs; these effects on GH were also enhanced by the presence of dex. T₃ treatment for 24 h increased GR mRNA; this effect was inhibited by the presence of dex. We next examined the influence of dex on GR and T₃R and β mRNAs, in parallel with effects of dex on the prolactin (PRL) target gene. Modulatory influences of T₃ on dex action were studied by treatment of cells with T₃ before and during dex treatment. Treatment with dex (0.1–10 μM) for 24 h reduced GR mRNA, an action enhanced by the presence of T₃ (100 nM). Dex treatment resulted in inhibition of PRL mRNA and release despite parallel inhibition of GR mRNA by dex; these effects were enhanced by the presence of T₃. In contrast to actions on GR, dex has no effect on T₃R mRNAs. These effects of T₃ and dex on receptor mRNAs suggest that glucocorticoid modulation of T₃ action is not related to direct actions on T₃R synthesis. In contrast, the mechanism of T₃ modulation of glucocorticoid action may be due in part to alteration of GR mRNA expression. Effects of T₃ and dex on target gene expression were observed in the presence of parallel reduction of their respective receptor mRNAs. This provides new evidence that interactions between these hormones are likely to be mediated by mechanisms other than regulation of receptor gene expression.     

慢性心力衰竭患者血清肌钙蛋白Ⅰ与心肌重构的相关性研究

目的研究慢性心力衰竭（CHF）患者血清心肌肌钙蛋白Ⅰ（cTnI）与心肌重构的相关性.方法入选失代偿性CHF患者120例,根据血清cTnI浓度水平分为：cTnI正常组（n=80）和cTnI升高组（n=40）.以左心房直径（LAd）、左心室直径（LVd）、室间隔厚度（IVS）、左室后壁厚度（LVPW）作为心脏结构改变指标,左室射血分数（LVEF）、E峰和A峰比值（E/A值）作为心脏功能指标,对上述指标进行组间比较.结果与cTnI正常组相比,cTnI升高组的LAd、LVd显著增高（P〈0.05）;而IVS、LVPW、LVEF、E/A值显著降低（P〈0.05）.相关分析显示：血清cTnI含量与LAd、LVd呈正相关（P〈0.05）,与IVS、LVPW、LVEF、E/A呈负相关（P〈0.05）,经性别、心衰病史、心功能分级与药物治疗校正后,上述相关性仍然存在,并具有统计学意义.进一步行多因素logistic回归分析,结果显示：LAd、LVd和心衰病史与cTnI升高呈正相关;而血管紧张素转换酶抑制剂（ACEI）治疗与cTnI升高呈负相关.结论血清cTnI浓度与心衰患者心肌重构及心功能具有显著相关性,此相关性可不依赖于年龄、性别、心衰病史、NYHA心功能分级和药物治疗而独立存在.监测心力衰竭患者血清cTnI浓度并采取相应的措施降低血清cTnI水平,对临床治疗和预防心力衰竭进展具有重要意义.     

运动对高血压心力衰竭患者血清肌钙蛋白Ⅰ的影响

目的观察症状限制性运动试验和运动训练对高血压心力衰竭患者心肌肌钙蛋白I（cTnI）的影响。方法30例高血压中度心力衰竭患者[NYHA分级Ⅱ～Ⅲ级,射血分数（1．7±9.3）％]与15例轻度心力衰竭患者及10例无心力衰竭受试者进行对比观察。患者均进行症状限制性运动试验和单期运动训练（达最大心率的80％以上,持续时间30min）,分别测定基础cTnI值、症状限制性试验后和运动训练后1～6h时的cTnI值。结果症状限制性运动试验后,中度心力衰竭患者cTM值由（37±21）pg／ml增加到（77±24）pg／d,其中9例中度心力衰竭患者和4例轻度心力衰竭患者的cTnI值升高到100pg／ml以上。无心力衰竭的受试者无论是静息时或是运动后,cTnI值均较低（P〈0．05）。结论高血压心力衰竭患者在症状限制性运动试验后cTnI值增加,其水平达到轻微的心肌损伤水平。这一现象对患者预后的影响值得进一步研究。     

慢性心力衰竭患者血清肌钙蛋白I与心肌重构的相关性研究

目的研究慢性心力衰竭(CHF)患者血清心肌肌钙蛋白I(cTnI)与心肌重构的相关性。方法入选失代偿性CHF患者120例,根据血清cTnI浓度水平分为cTnI正常组(n=80)和cTnI升高组(n=40)。以左心房直径(LAd)、左心室直径(LVd)、室间隔厚度(IVS)、左室后壁厚度(LVPW)作为心脏结构改变指标,左室射血分数(LVEF)、E峰和A峰比值(E/A值)作为心脏功能指标,对上述指标进行组间比较。结果与cTnI正常组相比,cTnI升高组的LAd、LVd显著增高(P<0.05);而IVS、LVPW、LVEF、E/A值显著降低(P<0.05)。相关分析显示血清cTnI含量与LAd、LVd呈正相关(P<0.05),与IVS、LVPW、LVEF、E/A呈负相关(P<0.05),经性别、心衰病史、心功能分级与药物治疗校正后,上述相关性仍然存在,并具有统计学意义。进一步行多因素logistic回归分析,结果显示LAd、LVd和心衰病史与cTnI升高呈正相关;而血管紧张素转换酶抑制剂(ACEI)治疗与cTnI升高呈负相关。结论血清cTnI浓度与心衰患者心肌重构及心功能具有显著相关性,此相关性可不依赖于年龄、性别、心衰病史、NYHA心功能分级和药物治疗而独立存在。监测心力衰竭患者血清cTnI浓度并采取相应的措施降低血清cTnI水平,对临床治疗和预防心力衰竭进展具有重要意义。     

Effect of treatment on ventricular function and troponin I proteolysis in reperfused myocardium

Effects of ischemia time and treatment interventions upon troponin I (TnI) proteolysis and function of reperfused myocardium were examined in isolated, perfused rabbit hearts. Hearts were randomized to 90 min aerobic perfusion, 15 min low-flow (1 ml/min) ischemia (I) and 60 min reperfusion (R) or 60 min low-flow I and 60 min R. Hearts subject to 60 min I and 60 min R received either no treatment, l -arginine treatment, or treatment with oxygen free radical (OFR) scavengers (mercapto-proponyl-glycine, catalase and superoxide dismutase). Hearts from cholesterol-fed rabbits were also studied after 60 min I and R. Isovolumic LV pressure and heart rate were recorded throughout and Western analysis of ventricular myocardium, using 3 specific antibodies, detected intact TnI (29 kDa) and TnI fragment (25 kDa). Hearts subject to 15 min I had minimal irreversible injury (TTC negative region=0.6+/-0.4% LV) but hearts subject to 60 min I had more extensive injury (TTC negative=40.7+/-5.8% LV). Recovery of rate-pressure product after 15 min I and 60 min R (56+/-9% of baseline) was better than after 60 min I and 60 min R (23+/-9%, P<0.01). Both l -arginine and OFR scavengers were associated with better recovery of function after 60 min I, (66+/-7% and 72+/-3% of baseline respectively, P<0.01 v no treatment) but cholesterol hearts had poor recovery after 60 min I (37+/-8%). The 25 kDa TnI (% total TnI immunoreactivity) was 8.7+/-0.9% in controls, 10.0+/-1.6% after 15 min I and 60 min R, and 17.4+/-2.4% after 60 min I and 60 min R (P<0.01 v controls and 15 min I). The proportion of 25 kDa TnI was increased in all hearts after 60 min I and did not change with treatment (l -arginine 16.8+/-1.8%, OFR scavengers 16.0+/-3.2%, cholesterol 14.0+/-1.9%). There was no relation between proportion of 25 kDa TnI and recovery of function. Samples from freshly excised rabbit hearts and human right atria also had 25 kDa TnI (relative intensities 8.5+/-2.3% and 5.1+/-2.6% respectively). Although TnI fragmentation increases after prolonged ischemia and reperfusion, the functional recovery of stunned myocardium is independent of degree of TnI fragmentation.