多西环素对心肌梗死后心功能的保护作用

目的:采用超声心动图观察大鼠心肌梗死(MI)模型中外源性基质金属蛋白酶抑制剂多西环素对左心室功能的保护作用。方法:通过结扎SD大鼠冠状动脉前降支建立MI模型。分为MI组(15只)、治疗组(16只),分别于术后即刻、术后2周、术后4周采用Acuson Sequoia 512超声心动图机分别测定左室前壁、后壁厚度以及左心室舒张末期内径和左室射血分数。结果:左室重量4周时治疗组比MI组轻(P<0.05);左室前壁厚度4周时治疗组大于MI组(P<0.05);左室舒张末期内径4周时MI组大于治疗组(P<0.05)。结论:经多西环素治疗后的MI SD大鼠,心功能得以改善,其机制与MI后外源性基质金属蛋白酶抑制剂参与心室重塑有关。     

瑞舒伐他汀对兔心肌梗死后心室重构及功能影响的机制研究

目的观察瑞舒伐他汀对新西兰大白兔心肌梗死后心室重构的影响,并探讨其可能机制。方法 45只雄性新西兰大白兔随机分成3组,假手术组(S组,n=15),心肌梗死对照组(MI组,n=15),瑞舒伐他汀干预组(R组,n=15)。MI组和R组大鼠结扎左冠状动脉前降支建立急性心肌梗死模型。MI组及S组术后24 h灌等量的生理盐水。R组于术后24 h直接灌胃法给药,给药剂量以10 mg/(kg·d)计算。干预2周后,进行心脏超声测定,然后随即处死新西兰大白兔,取出心脏,通过TUNEL法检测心肌梗死边缘区的细胞凋亡率,使用流式细胞仪法测定心肌梗死边缘区Caspase-3的表达,同时应用Western blot方法检测p38、p-p38在此区域的表达。结果 R组兔的左室舒张末期内径(LVEDD)、左室收缩末期内径(LVESD)较MI组减小,而左室射血分数(LVEF)较MI组增高;R组及MI组兔心肌梗死边缘区的心肌细胞凋亡率均高于S组,而R组兔的心肌细胞凋亡率低于MI组;R组兔心肌梗死边缘区与MI组p38表达比较未见明显差异,而前者Caspase-3及p-p38表达低于后者,差异具有统计学意义(P<0.05)。结论瑞舒伐他汀可抑制心室重构及改善心脏功能,其机制可能是通过抑制p38的磷酸化从而阻止Caspase-3的活化,最终抑制心肌细胞凋亡。     

不同剂量卡维地洛对心肌梗死后大鼠左室重构及心肌细胞凋亡的影响

目的观察不同剂量卡维地洛(CAR)对心肌梗死(MI)后大鼠左室重构及心肌细胞凋亡的影响。方法结扎大鼠冠状动脉前降支,随机分成三组:MI组,术后不用药,卡维地洛大剂量组(HCAR组),卡维地洛小剂量组(LCAR组),术后2d分别给予卡维地洛10 mg/kg和1.25 mg/kg。另外不手术不用药组为假手术组(SH组)。6周后测定左室重构指标及心肌细胞凋亡计数。结果卡维地洛用药组与MI组比较,左室重构明显改善,心肌细胞凋亡量明显减少,且有剂量依赖,大剂量组优于小剂量组。结论卡维地洛可改善AMI后大鼠的左室重构,并有剂量依赖性,减少心肌细胞凋亡可能是其重要因素之一。     

辛伐他汀对心肌梗死大鼠Smad7表达与心室重塑影响

目的:探讨辛伐他汀对大鼠心肌梗死(MI)后心室重构的作用及对心肌Smad7表达的影响.方法:建立大鼠MI模型,24 h后存活大鼠随机分成MI组(n=9)、辛伐他汀20 mg组(20 mg·kg-1·d-1,Sim2组, n=10)和40 mg组(40 mg·kg-1·d-1, Sim4组, n=9), 另设假手术组(Sham组, n=10).4周后观察血脂水平、心室重量指数、天狼猩红染色分析左室非梗死区胶原容积分数、苏木精-伊红染色及电镜观察心肌组织病理改变,并用免疫组化染色和RT-PCR检测Smad7在非梗死区的表达.结果:各组血脂水平差异无统计学意义, MI组左心室重量指数增加, 非梗死区Ⅰ型、Ⅲ型胶原容积分数及Ⅰ/Ⅲ比值均增加.与MI组相比,Sim组左室重量指数降低, 非梗死区Ⅰ型、Ⅲ型胶原容积分数及Ⅰ/Ⅲ比值下降, 但仍高于Sham组, 心肌组织病理结构改善.与MI组比较, Sim组Smad7表达增加.结论:辛伐他汀能有效地减轻MI后的心肌损伤和纤维化重构, 其机制与其调脂作用无关, 可能与促进Smad7的表达有关.     

金合欢素对心肌梗死大鼠诱导的室性心律失常影响

目的 研究金合欢素对心肌梗死(MI)大鼠诱导的室性心律失常影响.方法 体重180～200 g SPF级雄性SD大鼠30只,随机分为假手术组,MI组和金合欢素组,每组10只,后2组结扎左冠状动脉前降支建立MI模型.MI4周后,利用超声测量大鼠左室射血分数(LVEF)、左室短轴缩短率(LVFS)、左室收缩未期内径(LVID...     

兔骨髓间充质干细胞自体移植对缺血心肌心功能的影响

目的 :了解骨髓间充质干细胞 (MSCs)在心肌梗死 (MI)的缺血心肌微环境中转化为心肌细胞并改善心功能的可行性。方法 :结扎兔左前降支制作急性MI模型 ,骨穿抽取骨髓 ,分离培养扩增MSCs ,其中一组于培养基中加入 5 氮胞苷 (5 aza) 10 μmol/L。术后 2周进行MI瘢痕内移植 5 溴脱氧尿嘧啶 (BrdU)标记的MSCs,对照组注射培养基。MI术前、术后 3d及移植后 4周做超声心动图检测心功能 ,移植后 4周从右颈总动脉插管至左心室测左室压力变化 ,随后处死动物取左室标本作冰冻切片 ,采用免疫荧光方法鉴定植入细胞。结果 :细胞移植组左室切片中均可见BrdU染色阳性细胞即植入细胞 ,对照组未见BrdU染色阳性细胞。超声心动图检测证实移植后 4周细胞移植组左室收缩末期直径、舒张末期直径均小于对照组 (分别为P <0 .0 1及P <0 .0 5 ) ,小轴缩短率、射血分数均大于对照组 (均P <0 .0 1)。导管测压显示细胞移植组的左室舒张末期压低于对照组、左室压上升及下降最大速率高于对照组 (均P <0 .0 1)。加 5 aza细胞移植组与不加 5 aza组上述各指标差异无统计学意义。结论 :缺血心肌内注射MSCs可依赖组织微环境转化为心肌细胞修复梗死心肌 ,显著改善心功能 ,可用于MI的治疗。     

贝那普利及卡托普利对大鼠心肌梗死后心室重构及基质金属蛋白酶-2表达的影响

目的 研究大鼠心肌梗死(MI)后基质金属蛋白酶2(MMP-2)的变化,以及贝那普利(洛汀新)与卡托普利对MMP-2和心室重构的影响.方法 采用大鼠左冠状动脉前降支结扎法建立大鼠急性心肌梗死(AMI)模型.将50只Wistar大鼠随机分为伪手术组(C组)、洛汀新干预组(L组)、卡托普利干预组(K组)和心肌梗死对照组(MI组).手术后10周测定血流动力学参数,左室舒张末压(LVEDP)、左室内压最大上升速率(dP/dTmax)及左室内压最大下降速率(dP/dTmin).用ELISA方法测定血清中MMP-2的表达水平.处死大鼠后取出心脏,称取全心重量(THW)和左室重量(LVW),并分别除以体重(BW),以THW/BW、LVW/BW表示心脏及左室肥厚程度.结果 与C组比较,各手术组大鼠LVEDP,MMP-2,THW/BW,LVW/BW均显著增加(P<0.05),dP/dTmax,dP/dTmin均显著降低(P<0.05).与MI组比较,L组与K组LVEDP,MMP-2,THW/BW,LVW/BW均显著降低(P<0.05),dP/dTmax,dP/dTmin,均显著增加(P<0.05).结论 MMP-2参与了MI后心室重构,洛汀新与卡托普利通过抑制MMP-2的表达,明显减轻了MI后心室肥厚,改善左室功能,并且洛汀新与卡托普利在防止心室重构上无显著差别.     

心脏离体灌流装置观察细胞移植对心脏功能的影响

目的观察胚胎心肌细胞移植到大鼠急性心肌梗死区后对大鼠心脏功能的影响及其存活情况。方法100只成年大鼠随机分成2组。移植组开胸结扎大鼠冠状动脉后在梗死区内注射培养的胚胎心肌细胞悬液;对照组结扎冠状动脉后在与移植组相同的部位注射等量的细胞培养液。各组分别在移植后的48h、72h、1周、2周收集心脏标本,HE染色及抗5鄄溴脱氧尿核苷(5鄄BrdU)免疫组化染色。Langendorff心脏离体灌流装置测定移植术后第2周各组大鼠的心脏功能。结果移植组大鼠心脏左室收缩峰压(LVSP)、左室内压最大上升与下降速率( dp/dtmax,-dp/dtmax)与对照组相比明显升高,差异有非常显著意义(P<0.01),左室舒张期末压(LVEDP)明显降低,与对照组相比差异也有非常显著意义(P<0.01)。在移植组心肌梗死区内可以看到存活的胚胎心肌细胞,对照组未发现。结论胚胎心肌细胞移植能够改善大鼠的心脏功能,并且可以在大鼠的心肌梗死区内存活及分化。     

卡维地洛对心梗大鼠远期心室重构的影响及其作用机制

目的:探讨卡维地洛(Carv)对心肌梗死(MI)大鼠心室心肌重构的影响及其作用机制。方法:结扎30只大鼠左冠状动脉建立MI模型后,随机分为Carv组(n=15)及MI组(n=15)。再另设假手术(Sham)组(n=15)。Carv组给予Carv(日剂量2 mg/kg),分2次灌胃;Sham组及MI组均给予等量蒸馏水灌胃。24周后,观察心室重构和左室非梗死区心肌内4-羟基壬烯醛(4-HNE)和过氧化物丙二醛(MDA)的含量及表达。结果:24周后,超声显示,与Sham组比较,MI组大鼠心功能明显降低,左室舒张末期内径(LVEDD)明显增大,左室短轴缩短率(FS)和心脏射血分数(EF)明显降低(P0.05,P0.01)。MI组大鼠左室非梗死区心肌内4-HNE和MDA的含量明显增加,表达明显增强(P0.05,P0.01)。Carv组大鼠左室非梗死区心肌组内4-HNE和MDA的含量比MI组明显降低(P0.05,P0.01)。结论:MI 6月后,心肌内4-HNE、MDA的活性仍然较高,氧化应激反应仍持续,Carv可以促进活性醛的代谢,对心脏具有保护作用,可改善预后。     

心肌梗死后不同时间兔自体骨髓基质细胞移植对疗效的影响

目的:探讨不同时间进行兔自体骨髓基质细胞(BMSCs)移植对兔心肌梗死疗效的影响。方法:冠状动脉左前降支结扎制作心肌梗死模型的新西兰兔56只,随机分为4个组别,每个组别再分为细胞移植治疗组(8只)和对照组(6只)。分别于心肌梗死后1、2、3、4周将自体BMSCs或无血清培养基直接注射至心肌梗死区。观察4周,超声心动图检测心功能,继之处死动物取左室壁移植部位行病理检测,免疫组化法检测肌钙蛋白T(cTnT)和溴脱氧尿核苷(Brdu)和Ⅷ因子相关抗原,并通过Ⅷ因子阳性内皮细胞计算毛细血管密度。结果:细胞移植组,左室移植部切片见BrdU染色阳性及cTnT染色阳性细胞,而对照组未见BrdU染色阳性及cTnT染色阳性细胞。细胞移植治疗组左室射血分数、左室短径缩短率显著高于对照组(P<0.01);左室收缩末期容积、左室舒张末期容积小于对照组(P<0.01);经Ⅷ因子阳性内皮细胞计算,细胞移植组毛细血管密度大于对照组。以上各指标均以2周、3周移植组改善最为明显。结论:移植细胞可在心肌梗死区分化成心肌细胞,并促进新生毛细血管生成,显著改善心功能。以心肌梗死后2～3周进行自体BMSCs移植疗效更为显著。     

胰岛素对大鼠心肌梗死后心室重构和心脏功能的影响及其机制

目的:探讨胰岛素对大鼠心肌梗死(MI)后心室重构和心脏功能的影响及其机制。方法: 80只成年雄性Sprague-Dawley大鼠行冠状动脉左前降支(LAD)结扎制备MI模型,随机分为5组:即假手术(Sham)组(n=20)、生理盐水对照(MI+NS)组(n=20)、胰岛素治疗(MI+Ins)组(n=20)、肿瘤坏死因子α(TNF-α)拮抗剂益赛普治疗(MI+En)组(n=10)及Ins+En治疗(MI+Ins+En)组(n=10)。用ELISA法检测各组大鼠在MI后1周和4周时,心肌及血清TNF-α的水平。超声心动图测定各组大鼠左室射血分数(EF)、缩短分数(FS)和左心室舒张末内径(LVEDD)、左心室收缩末内径(LVESD)、经右颈总动脉插管测定血压(BP)、左室舒张压(LVDP)和最大左室舒张压/收缩压变化速率(±LVdp/dtmax）。结果: 大鼠MI后心肌中TNF-α增加,Ins治疗可明显降低大鼠心肌中TNF-α的含量(P<0.05,n=6)。Ins治疗组大鼠EF、FS、LVDP和±LVdp/dtmax均明显高于对照组(P<0.05,n=10),LVESD明显低于对照组(P<0.05,n=10)。与单独En治疗组相比,Ins+En治疗组大鼠EF、FS、LVDP和±LVdp/dtmax明显升高、LVESD明显降低(P<0.05,n=10)。结论: Ins可抑制MI后心室的扩张,改善心脏功能,但其机制不依赖于抑制心肌TNF-α的产生。     

Early Short-Term Vagal Nerve Stimulation Attenuates Cardiac Remodeling After Reperfused Myocardial Infarction

BackgroundVagal nerve stimulation (VS) has been suggested to be an effective adjunct to reperfusion therapy in myocardial infarction (MI). However, the effect of VS on left ventricular (LV) remodeling after reperfused MI has not been examined.Methods and ResultsWe investigated the effects of early, brief VS on acute inflammatory reactions (study 1) and chronic LV remodeling (study 2) in a rabbit model of reperfused MI. In study 1, rabbits were subjected to 60-minute coronary artery occlusion followed by reperfusion alone (MI, n = 8) or treated with 24-hour VS (MI-VS, n = 8). At 24 hours after ischemia-reperfusion, MI-VS rabbits showed significantly decreased myocardial infiltration of neutrophils and reduced myocardial expressions of tumor necrosis factor-α and matrix metalloproteinase-8 and -9, compared with MI rabbits. Myocardial expression of interleukin-6 was not affected by VS. In study 2, rabbits were subjected to coronary occlusion and reperfusion alone (n = 16) or treated with VS for 3 days (n = 14). At 8 weeks after ischemia-reperfusion, MI-VS rabbits showed significantly improved LV dysfunction and dilatation, and significantly reduced infarct size, infarct wall thinning, and LV weight compared with MI rabbits.ConclusionEarly, short-term VS attenuates LV remodeling after reperfused MI, which may be associated with suppression of acute inflammatory reactions.     

An elastic, biodegradable cardiac patch induces contractile smooth muscle and improves cardiac remodeling and function in subacute myocardial infarction.

OBJECTIVES: Our objective in this study was to apply an elastic, biodegradable polyester urethane urea (PEUU) cardiac patch onto subacute infarcts and to examine the resulting cardiac ventricular remodeling and performance. BACKGROUND: Myocardial infarction induces loss of contractile mass and scar formation resulting in adverse left ventricular (LV) remodeling and subsequent severe dysfunction. METHODS: Lewis rats underwent proximal left coronary ligation. Two weeks after coronary ligation, a 6-mm diameter microporous PEUU patch was implanted directly on the infarcted LV wall surface (PEUU patch group, n = 14). Sham surgery was performed as an infarction control (n = 12). The LV contractile function, regional myocardial wall compliance, and tissue histology were assessed 8 weeks after patch implantation. RESULTS: The end-diastolic LV cavity area (EDA) did not change, and the fractional area change (FAC) increased in the PEUU patch group (p < 0.05 vs. week 0), while EDA increased and FAC decreased in the infarction control group (p < 0.05). The PEUU patch was largely resorbed 8 weeks after implantation and the LV wall was thicker than infarction control (p < 0.05 vs. control group). Abundant smooth muscle bundles with mature contractile phenotype were found in the infarcted myocardium of the PEUU group. The myocardial compliance of the PEUU group was distributed between normal myocardium and infarction control (p < 0.001). CONCLUSIONS: Implantation of a novel biodegradable PEUU patch onto a subacute myocardial infarction promoted contractile phenotype smooth muscle tissue formation and improved cardiac remodeling and contractile function at the chronic stage. Our findings suggest a new therapeutic option against post-infarct cardiac failure.     

心肌梗死大鼠左心室收缩与舒张功能的改变及其影响因素

目的 探讨心肌梗死大鼠左心室收缩和舒张功能的改变、以及心室重构对心室舒缩功能的影响.材料和方法结扎Wistar大鼠左冠状动脉、制成心肌梗死模型,6周后测定左室心肌力学指标,心肌胶原含量、血浆及心肌的血管紧张素Ⅱ(Aug Ⅱ)浓度.结果 心肌梗死组与对照组比较,LVPSP、+dp/dt_(max)、dp/dt_(max)绝对值及V_(max)明显降低(P<0.01),LVEDP增加(P<0.01),T值延长(P<0.01),MAP无差异.心肌梗死组与对照组比较、心肌羟脯氨酸和心肌胶原含量明显增高(P均0.01),心肌AngⅡ含量明显升高(P<0.01)、血浆AngⅡ浓度无显著差异.结论 心肌梗死后左室收缩与舒张　功能明显降低,同时出现心肌细胞的肥大和纤维细胞的增生以及间质纤维化、后者可进一步导致和加重心脏泵血功能的异常.     

Induction of left ventricular remodeling and dysfunction in the recipient heart after donor heart myocardial infarction: new insights into the pathologic role of tumor necrosis factor-alpha from a novel heterotopic transplant-coronary ligation rat model

OBJECTIVES: The present study investigated the effects of tumor necrosis factor (TNF)-alpha and angiotensin II (ANG II) on cardiac remodeling and dysfunction at the early stage of acute myocardial infarction (MI) by using a novel heterotopic cardiac transplantation-coronary ligation model. BACKGROUND: A recent clinical study has demonstrated a possible role of monocytosis in the development of left ventricular (LV) remodeling in patients with acute MI reperfusion. METHODS: We performed isogenic heterotopic cardiac transplantation and simultaneous coronary ligation to produce MI in the donor heart and to evaluate the hearts of both donors and recipients in Lewis rats. RESULTS: A significant decrease in LV fractional shortening and positive rate of rise in LV pressure and a significant increase in LV end-diastolic dimension/body weight and LV end-diastolic pressure were observed in the recipient hearts in the ligation group on day 7. TNF-alpha was significantly elevated not only in the plasma but also in the recipient hearts in the ligation group. In contrast, ANG II was significantly increased only in the infarct region of the donor hearts, but not in the plasma. Furthermore, the recipients' transient LV remodeling and dysfunction were completely abolished by the intravenous administration of a TNF-alpha antagonist. CONCLUSIONS; We developed a novel cardiac transplantation-coronary ligation model capable of inducing MI in the absence of downstream hemodynamic effects and allowing differential quantification of indexes of cardiac remodeling in vivo, including the local and remote effects of ANG II and TNF-alpha on cardiac remodeling.     

Hypoxia training attenuates left ventricular remodeling in rabbit with myocardial infarction

Objective Previous studies showed that hypoxia preconditioning could protect cardiac function against subsequent myo-cardial infarction injury. However, the effect of hypoxia on left ventricular after myocardial infarction is still unclear. This study therefore aims to investigate the effects of hypoxia training on left ventricular remodeling in rabbits post myocardial infarction. Methods Adult male rabbits were randomly divided into three groups： group SO （sham operated）, group MI （myocardial infarc-tion only） and group MI-HT （myocardial infarction plus hypoxia training）. Myocardial infarction was induced by left ventricular branch ligation. Hypoxia training was performed in a hypobaric chamber （having equivalent condition at an altitude of 4000 m, FiO214.9%） for 1 h/day, 5 days/week for four weeks. At the endpoints, vascular endothelial growth factor （VEGF） in the plasma was measured. Infarct size and capillary density were detected by histology. Left ventricular remodeling and function were as-sessed by echocardiography.Results After the 4-week experiment, compared with the group SO, plasma VEGF levels in groups MI （130.27 ± 18.58 pg/mL,P〈 0.01） and MI-HT （181.93 ± 20.29 pg/mL,P〈 0.01） were significantly increased. Infarct size in Group MI-HT （29.67% ± 7.73%） was deceased remarkably, while its capillary density （816.0 ± 122.2/mm2） was significantly increased. For both groups MI and MI-HT, left ventricular end-diastolic and end-systolic dimensions were increased whereas left ventricular ejection fraction was decreased. However, compared with group MI, group MI-HT diminished left ventricular end-diastolic （15.86 ± 1.09 mm,P〈 0.05） and end-systolic dimensions （12.10 ± 1.20 mm,P〈 0.01） significantly and im-proved left ventricular ejection fraction （54.39 ± 12.74 mm,P〈 0.05）.ConclusionHypoxia training may improve left ven-tricular function and reduce remodeling via angiogenesis in rabbits with MI.     

Left atrial transport function in myocardial infarction. Importance of its booster pump function.

After myocardial infarction (MI), left ventricular (LV) end-diastolic pressure (EDP) is higher than mean pulmonary artery wedge pressure because of powerful atrial contraction. To evaluate the significane of atrial contraction to left ventricular function we studied 10 control (C) patients without cardiac disease and 17 patients from three to six weeks after acute myocardial infarction. Cardiac catheterization with simultaneous left ventricular diastolic pressure (DP) and left ventricular cineangiograms were obtained. Left ventricular volumes and pressure were (mean +/- SD): (SEE ARTICLE). Although left ventricular stroke volume was lower in the patients with myocardial infarction than in the control subjects (46 versus 56 ml/m2), atrial contraction contributed more to left ventricular filling during diastole (which is the same as left ventricular stroke volume) in the patients with myocardial infarction than in the controls (16 versus 10 ml/m2). The average atrial contribution to left ventricular end-diastolic volume was 11.9 per cent (C), 15.4 per cent (MI); to left ventricular end-diastolic pressure 20 per cent (C), 38.7 per cent (MI); and to left ventricular stroke volume 21.7 per cent (C), 35.1 per cent (MI). Atrial contribution to left ventricular stroke volume was 56 per cent in patients with a cardiac index less than or equal to 2.0 liters/min/m2 and 31 per cent in those with a cardiac index greater than 2 liters/min/m2 (p less than 0.01). Atrial contraction contributed 35 per cent to left ventricular stroke volume in patients with normal end-diastolic volume and in those with increased end-diastolic volume and 10 per cent to end-diastolic volume in patients with increased end-diastolic volume (p less than 0.001). In patients with myocardial infarction, atrial contraction made a large contribution to left ventricular filling and stroke volume irrespective of the type of left ventricular functional derangement that was present. The "booster pump" function of the atrium cannot be ignored in assessing left ventricular performance.     

Relation of circulating interleukin-6 to left ventricular remodeling in patients with reperfused anterior myocardial infarction

BACKGROUND: During the remodeling process after myocardial infarction (MI), the expression of proinflammatory cytokines is enhanced in the myocardium. However, only a few clinical studies have been conducted on cytokine involvement in left ventricular (LV) remodeling after MI. HYPOTHESIS: Circulating proinflammatory cytokines may be involved in LV remodeling in patients with reperfused MI. METHODS: We studied 25 patients with acute anterior MI who had undergone coronary reperfusion therapy, and 10 normal control subjects with no cardiac disease. In all patients, LV ejection fraction, end-diastolic volume index (EDVI), and end-systolic volume index (ESVI) were determined using left ventriculography at the acute phase and 6 months after onset. The delta EDVI and delta ESVI were calculated as the value of LV volume reduction, suggesting LV reverse remodeling. Serum levels of interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha were measured using enzyme-linked immunosorbent assay. RESULTS: Serum levels of IL-6 and TNF-alpha at the acute phase were significantly higher in patients with MI than in control subjects (both p < 0.05). The IL-6 levels correlated well negatively with delta EDVI (r = 0.779, p = 0.039), whereas no correlation was found for TNF-alpha. According to multivariate analysis, IL-6 at the acute phase was a significant independent predictor for LV remodeling after reperfused MI (p = 0.007). CONCLUSIONS: Circulating IL-6 levels correlated closely with LV geometric changes during the remodeling process in patients with reperfused MI. Our study addresses the usefulness of another marker for LV remodeling after MI.     

Effect of hepatocyte growth factor on left ventricular remodeling after acute myocardial infarction in canine

Background and objectives To investigate the effect of hepatocyte growth factor (HGF) on left ventricular (LV) remodeling after acute myocardial infarction (AMI). Methods AMI was produced by ligation of proximal left anterior descending coronary artery(LAD) in 12 mongrel canines. These animals were randomized into 2 groups. In HGF group (n=6), canines were injected with pcDNA3-HGF lml (about 300ug) at the margin of infarcted myocardium; in control group (n=6) canines were injected with equal volume of normal saline. Cardiac function and left ventricular remodeling were evaluated with echocardiography at 1, 4, 8 weeks after MI. LV myocardium specimens were obtained at 8 weeks and stained with hematoxylin and eosin for histological examination or with sirius red to assess the collagen content. Results Compared with control group, LVEF in HGF group was significantly higher at 4 weeks (49.61+6.66 vs 39.84+6.39; P＜0.05) and at 8 weeks (51.57+8.53 vs 40.61+7.67; P＜0.05) after AMI, while LVESV was significantly lower in HGF group than that in control group at 8 weeks after AMI (18.98+3.47 vs 25.66+5.86; P＜0.05). Posterior left ventricular wall thickness decreased significantly from 1 wk to 8 wks after AMI in control group, while remained unchanged in HGF group. Compared with control group, histological examination showed more neovascularization and less scar, and sirius red staining indicated higher volume of type Ⅲ collagen (7.10&#177;4.06% vs 3.77&#177;1.09%; P＜0.05) and lower collagen Ⅰ/Ⅲ ratio value (1.11&#177;0.52 vs 2.94&#177;2.48; P＜0.05)in HGF group. Conclusion HGF gene transfer might improve cardiac function and LV remodeling after acute myocardial infarction by stimulating angiogenesis, reducing fibrosis, and reducing myocardial scarring.     

重组中期因子对大鼠心肌梗死后心室重塑及Ⅲ型前胶原氨基端肽的影响

目的研究早期应用中期因子（MDK）对大鼠心肌梗死后心室重塑的作用及对Ⅲ型前胶原氨基端肽（PⅢNP）与心功能的影响。方法结扎Wistar大鼠左冠状动脉前降支建立心肌梗死动物模型。32只大鼠随机分为3组：对照组（Sham,8只）、心肌梗死组（MI,12只）和心肌梗死＋人重组中期因子干预组（MI＋MDK,12只）。造模成功后1μg／200g人重组中期因子在梗死周围分5点注射给药。4周后,所有大鼠行血流动力学、PⅢNP、微血管、胶原的测定及心脏标本的病理学分析。结果与MI组比较,MI＋MDK组的SBP、MAP、LVSP和±dp／dtmax显著增高,而LVEDP显著降低（P〈0．01）;血清PⅢNP值显著增加（P〈0．01）。病理标本分析：与MI组相比,MI＋MDK组梗死区中胶原容积分数显著增加,非梗死区中显著减少;MI＋MDK组有更多新生血管出现（P〈0．05）;MI＋MDK组炎细胞浸润、梗死面积、心肌肥大程度、心室重量明显减轻（P〈0．01）。结论急性心肌梗死大鼠早期应用MDK能发挥血管形成和胶原刺激的作用,对延缓急性心肌梗死后心室重塑发挥重要的作用。