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P-選凝素與心肌缺血-再灌注損傷

研究心肌缺血-再灌注損傷中P-選凝素(P-selectin)的重要作用.P-selectin是一種糖蛋白黏附因子, 存在于內皮細胞和血小板,并介導血小板、內皮細胞和多形核白細胞(PMNs)等之間的相互作用,且與一氧化氮有著密切的關系,形成了許多復雜的炎癥病理過程,在心肌缺血-再灌注損傷中起到了關鍵的作用.特別是P-selectin與晚期再灌注損傷、血小板及心肌損傷中治療作用、最新的P-selectin基因缺陷小鼠和糖尿病小鼠等的心肌缺血-再灌注損傷中表現的深入研究,使其在缺血-再灌注損傷中的重要性和復雜性顯得更加突出.

血管緊張素轉換酶抑制劑對心肌再灌注損傷的作用

心肌再灌注損傷可表現為再灌注性心律失常、心肌頓抑和心肌壞死.研究表明心臟局部的腎素血管緊張素系統和冠狀動脈內皮細胞功能失常在心肌再灌注損傷中起重要作用.血管緊張素轉換酶抑制劑能抑制轉換酶活性,減少血管緊張素Ⅱ的形成,并能作用于激肽酶Ⅱ,抑制緩激肽的降解,后者可促進前列環素和一氧化氮(NO)的產生.近年來血管緊張素轉換酶抑制劑被用于防護心肌再灌注損傷,在防護再灌注性心律失常、心肌頓抑和心肌壞死等方面顯示了較好的治療效果.

自身成體干細胞移植治療心肌梗死

心血管疾病,尤其是心肌梗死已成為人類死亡的主要疾病.自身成體干細胞移植為心肌梗死的治療帶來了新的希望.目前可供移植的種子細胞包括骨骼肌衛星細胞,骨髓干細胞,內皮祖細胞,自體移植避免了免疫排斥和倫理道德問題.近期實驗表明移植的干細胞能在心肌疤痕中存活,增強心功能.當前需要進一步研究干細胞移植后與心肌微環境的聯系,理想的移植細胞數目和移植技術以及對整個心功能可能產生的影響.

冠狀動脈旁路移植術患者術后早期運動耐量改善的影響因素

目的 探討冠狀動脈旁路移植術(CABG)患者術后早期運動耐量改善的影響因素,以提高手術療效.方法隨機選擇30例行CABG患者,術前和術后1～3個月進行平板運動試驗(TET),以手術前后運動功量的差值為應變量,各項臨床指標與手術情況為自變量,進行Logistic多元回歸分析. 結果 無手術死亡.術后運動功量等運動耐量指標及心肌缺血指標有明顯改善(Plt;0.001),術前左心功能、心肌梗死史、心絞痛、高血壓和乳內動脈(IMA)移植是影響手術療效的主要因素. 結論 CABG能顯著提高運動耐量,改善心肌缺血,了解并重視這些影響因素將有助于更好地選擇手術病例,預測手術療效.

The Short and Medium Term Effect on Myocardial Contractile Force after Implantation of Autologous Endothelial Progenitor Cells

Objective To study the short and medium term effect of myocardial contractile force by implantation of endothelial progenitor cells （EPCs） in the myocardial infarction model. Methods Hundred and twenty SD rats were equally and randomly divided into experimental group and control group （60 rats in each group）. Acute myocardial infarction model was created by ligation of LAD. Autologous EPCs were purified from peripheral blood then implanted into the acute myocardial infarct site via topical injection. IMDM were used in control group. Specimens and muscle strip were harvested at 3, 6 weeks, 6, 8 and 12 months after EPCs implantation for contractile force study and to detect the expression of vascular endothelial growth factor（VEGF）, basic fibroblast growth factor （bFGF） and Ⅷ factor by immunohistology and video image digital analysis system. Results The expression of VEGF, bFGF and the microvessel counts in experimental group were much higher than those of control group（P〈 0.01） at 3, 6 weeks and 6 months after transplantation. The contractile force in experimental group was better than that in control group（P〈0.01） at the same time. But from 8 months after implantation, the contractile force and so on were not up in the experimental group. Conclusion EPCs, after being implanted into infarct myocardium, shows the ability of improvement of the contractile performance in infarcted myocardium by means of angiogenesis and vasculogenesis and the medium term results are persistent.

卡托普利對缺血-再灌注鼠心肌一氧化氮及其合酶活性的影響

目的 研究一氧化氮(NO)和一氧化氮合酶(NOS)在心肌再灌注損傷中的作用,探討卡托普利(captopril)對缺血-再灌注鼠心肌保護的機制. 方法 采用Langendorff離體鼠心灌流模型,將18只SD大白鼠隨機分為3組(每組6只),對照組、缺血-再灌注組、卡托普利組.觀察心肌NOS同工酶活性、過氧化物歧化酶活性、丙二醛含量、肌酸激酶含量和冠脈流出液NO的變化. 結果 缺血-再灌注組與對照組比較心肌誘導型NOS(iNOS)活性增高(P＜0.001),而心肌原生型NOS(cNOS)活性及總NOS活性顯著降低(Plt;0.001,0.05),冠脈流出液NO含量下降(Plt;0.01).卡托普利組再灌注30分鐘,心肌iNOS活性低于缺血-再灌注組(Plt;0.01),cNOS活性和總NOS活性高于缺血-再灌注組(Plt;0.01,0.05),再灌注期間冠脈流出液NO水平高于缺血-再灌注組(Plt; 0.01),心肌損傷較缺血-再灌注組減輕. 結論 心肌NOS同工酶活性及NO產生的失常是心肌再灌注損傷的重要機制之一,卡托普利可通過調節心肌NOS同工酶活性,維持正常的NO水平,起到心肌保護作用.

Angiogenesis and cytokine secretion induced by autologous bone marrow mesenchymal stem cells implantation into infarcted myocardium

Objective To study the effect of bone marrow mesenchymal stem cells(MSCs) implantation into infarcted myocardium on cytokine secretion and angiogenesis. Methods 24 Guizhou xiang porcine were equally divided into experimental group and control group randomly. Three ml bone marrow was extracted from the posterior superior iliac spine. MSCs were cultured according to the methods of Wakitani’s. After being co-cultured with 5-azacytidine for 24 hours, these cells were labeled with bromodeoxyuridine(BrdU). Autologus MSCs were implanted into the acute myocardial infarct site both via the distal segment of the ligated left anterior descending artery (LAD) and topical injection. 3 amp; 6 weeks after transplantation, the samples from experimental group and control group were collected to detect the expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and Ⅷ factor by immunohistology and video image digital analysis system. Results The expression of VEGF, bFGF and the microvessel counts in the experimental group were much higher than those of control group (Plt;0.01) at 3 and 6 weeks after transplantation. Conclusion MSCs, after being implanted into infarcted myocardium, shows the ability of secreting VEGF, bFGF, with subsequent angiogenesis.

bFGF緩釋微膠囊埋藏部位對兔血管新生的影響

目的 通過局部心外膜下應用堿性成纖維細胞生長因子(bFGF)緩釋微膠囊,探討其治療心肌梗死的最佳埋藏部位,為進一步臨床應用提供理論依據. 方法 24只新西蘭大白兔隨機分為對照組(Ⅰ組),空白膠囊組(Ⅱ組),bFGF緩釋微膠囊組(Ⅲ組,每只膠囊含bFGF 1μg),每組8只.開胸結扎冠狀動脈前降支根部,Ⅱ組、Ⅲ組于左旋支,前降支交界區心外膜下埋藏空白微膠囊,bFGF緩釋微膠囊各5只.術后5周,免疫組織化學測定心肌梗死邊緣區,膠囊埋藏區微血管數. 結果 與Ⅰ組、Ⅱ組相比較,Ⅲ組心肌梗死邊緣區微血管數目明顯增多(Plt;0.01),膠囊埋藏區3組間微血管數差別無顯著性意義(Pgt;0.05). 結論 bFGF緩釋微膠囊組織相容性較好,在靠近缺血心肌的正常心肌心外膜下埋藏,可以達到理想的誘導缺血心肌血管新生的效果.

雙瓣膜置換患者圍術期心排血量與呼出氣二氧化碳的關系

目的 探討雙瓣膜置換術患者圍術期心排血量監測,提高手術安全性和預測患者預后,及時調整治療方案.方法 根據Fick原理將呼出氣二氧化碳(ETCO2)監測用于估計患者圍術期心排血量(CO),并與有創性溫度稀釋法進行比較.將1991年10月以來隨機選擇20例雙瓣膜置換患者分為兩組,對照組:使用常規心肌保護液;用藥組:常規心肌保護液中加入山莨菪堿,30mg/L.常規體外循環,冠狀竇逆行灌注,分別于麻醉前、轉流前、轉流結束、手術結束、術后2小時、4小時、8小時、12小時和24小時測定心臟指數(CI)、左心室收縮做功指數(LVSWI)、右心室收縮做功指數(RVSWI)、肺血管阻力(PVR)、全身血管阻力(SVR)、ETCO2、動脈血二氧化碳分壓(PaCO2).結果 對照組恢復心臟灌注后CO的增加與ETCO2變化無相關關系,用藥組CO增加較對照組顯著,且與ETCO2密切相關,CO的變化與ETCO2在各時點的變化呈正相關(P＜0.05);同時對照組在心臟復跳后PaCO2持續增加與術前及同時間用藥組相比有差異(P＜0.05).結論 山莨菪堿可改善肺循環,減少分流,可使ETCO2正確地反映CO變化,是一種既無創,又方便、經濟并能連續進行CO監測的方法.

胸腺瘤合并重癥肌無力及單純紅細胞再生障礙性貧血二例