白介素1β在升主动脉瘤和Debakey Ⅰ型胸主动脉夹层中的表达研究

目的 探讨白介素1β( interleukin-1β,IL-1β)在Debakey Ⅰ型胸主动脉夹层(TAD)和升主动脉瘤(ATAA)中的表达情况.方法 TUNEL染色、免疫组织化学染色、Western blot、实时定量PCR分别检测11例TAD,10例ATAA及7例正常主动脉标本的IL-1β、MMP-9、p38和JNK蛋白及中膜细胞凋亡在主动脉中膜中的表达和定位,并分析IL-1β的表达与中膜平滑肌细胞凋亡、MMP-9、p38和JNK蛋白表达的关系.结果 TAD和ATAA组中膜细胞凋亡较对照组高(P＜0.01).IL-1β的表达在正常组、TAD组、TAA组中逐渐升高(P＜0.01).MMP-9在TAD和ATAA组中的表达较对照组明显升高(P＜0.01).TAD组中,IL-1β与MMP-9和p38的表达呈正相关(P ＜0.01);TAA组中,IL-1β和细胞凋亡呈正相关(P＜0.01).结论 IL-1β在Ⅰ型主动脉夹层和升主动脉瘤中高表达,可能通过上调MMP-9的表达和(或)增加中膜细胞凋亡起作用,作用的信号传导通路可能是p38而非JNK信号转导通路.     

γ-干扰素在升主动脉瘤和Debakeyl型胸主动脉夹层中的表达研究

目的：探讨γ－干扰素在DebakeγI型胸主动脉夹层（TAD）和升主动脉瘤（ATAA）中的表达情况及可能作用机制。方法：TUNEL染色、免疫组织化学染色、westernblot、实时定量PCR分别检测11例TAD,10例ATAA及7例对照主动脉的中膜细胞凋亡、MMP－9、INF－γ、p38和JNK蛋白在主动脉中膜中的表达和定位,并分析INF－γ的表达与中膜平滑肌细胞凋亡、MMP－9、p38和JNK蛋白表达的关系。结果：TAD和ATAA组中膜细胞凋亡较对照组高（P〈O．01）。IFN－γ和MMP－9在TAD和ATAA组中的表达较对照组明显升高（P〈O．01）,而两组间无明显差异。TAA组中,IFN－γ与MMP－9、JNK和中膜细胞凋亡呈正相关（P=0．02,0．02,P〈0．01）。结论：INF－γ在升主动脉瘤中高表达,可能通过上调MMP－9的表达和／或增加中膜细胞凋亡起作用,作用的信号传导通路可能是JNK信号转导通路。     

热休克蛋白27在人胸主动脉夹层的表达研究

目的：探讨热休克蛋白（heat shock protein，HSP）27在胸主动脉夹层（thoracic aortic dissection，TAD）中的表达情况，并初步了解其在TAD中的可能作用。方法：组织化学染色检测TAD病理特征，免疫组织化学染色检测HSP27在动脉壁中的表达和定位，Western Blot验证其表达，并分析HSP27表达与TAD患者临床病理参数如直径、高血压和炎症反应等的关系。结果：Western blot和免疫组化染色均显示HSP27在两组标本中均有表达，TAD组表达较正常组减低。HSP27蛋白主要位于中膜和外膜小血管和炎性细胞的胞质。相邻切片α肌动蛋白表达分布与HSP27基本一致。HSP27表达与其直径、患者高血压、急慢性病程和年龄等参数无明显相关性，这可能与例数较少有关。结论：HSP27蛋白在TAD中表达减少，中膜平滑肌细胞（smooth muscle cell，SMC）是其主要细胞来源；HSP27可能通过调节肌动蛋白和SMC的功能等机制在TAD发挥作用，需进一步研究证实。     

胸主动脉夹层动脉壁TGF-β1表达与细胞外基质分布

目的 比较胸主动脉夹层与正常主动脉肇转化生长因子(TGF)-β1分布、表达的差异并分析TGF-β1表达与细胞外基质的关系,探讨胸主动脉夹层的发病机制.方法 夹层组为20例胸主动脉夹层病例手术切除标本,对照组为20例心脏移植供体主动脉标本.所有主动脉标本采用苏木精-伊红、Verhoeff弹力纤维染色及Masson三色染色法处理,分析细胞外基质的特征.以抗TGF-β1及α-平滑肌肌动蛋白单克隆抗体为第一抗体,采用双抗免疫荧光技术分析TGF-β1在动脉壁中的分布,并通过荧光定量法比较两组间以及动脉壁不同层次间TGF-β1表达的差异.结果 病理形态学显示,夹层主动脉壁中膜层弹力纤维减少、断裂伴胶原纤维增生.TGF-β1在夹层组及对照组动脉壁内不均匀分布,中膜层中表达水平最高,其次为内膜层,外膜层最低.两组间比较,TGF-β1表达(单位:信号强度)夹层组动脉壁全层(70.71±9.7对64.54±5.18,P<0.05),中膜层(79.26±12.77对68.28 ±7.98,P<0.01)和外膜层(60.04±12.07对51.43±8.09,P<0.05)均高于对照组,内膜层两组表达差异无统计学意义(62.54±8.81对62.63±6.12,P>0.05).病理形态分析显示,动脉中膜层TGF-β1主要表达于弹力纤维内,夹层组较对照组提高34.83%.危险因素分析提示年龄、性别、主动脉最大直径、夹层分型等因素与TGF-β1表达无相关性.结论 TGF-β1在主动脉壁内呈不均匀分布,且在胸主动脉夹层动脉壁中表达增强.TGF-β1在夹层中膜层弹力纤维中表达明显增强,对主动脉夹层的形成具有重要意义.     

急性升主动脉夹层基质金属蛋白酶-9的表达和血管平滑肌细胞病变

目的 观察急性升主动脉夹层(AAD)基质金属蛋白酶-9(MMP-9)表达和中膜血管平滑肌细胞(VSMC)病变.方法 35例急性AAD病例为研究对象(病变组),21例同期心脏移植供心者的升主动脉为对照组,应用透射电镜、免疫组化等方法,观察病变主动脉壁VSMC和基质变化;检测MMP-9在病变组和对照组血管壁中的表达;并将病变组按瘤径分为<55 mm和瘤径≥55 mm两个亚组,比较组间MMP-9表达情况并探讨吸烟、高血压病、瘤径等因素对MMP-9表达的影响.结果 病变组中膜VSMC合成功能旺盛,VSMC密度减小,弹性纤维崩解,管壁纤维化;对照组主动脉壁未见异常.对照组主动脉壁几乎不表达MMP-9;病变组中膜VSMC大量表达MMP-9(P<0.001),且其与瘤径(P<0.05)和合并高血压病(P<0.01)呈正相关,两亚组中,大瘤径亚组MMP-9表达显著(P<0.05).结论 血压升高增强升主动脉VSMC分泌功能,促进MMP-9表达,破坏弹性蛋白等基质成分,引起主动脉壁纤维化,管壁抗张强度下降,致局部主动脉内膜撕裂发生急性AAD.     

人工血管内支架与腹主动脉的生物相容性

目的评价人工血管内支架与腹主动脉的生物相容性。方法用膨体聚四氟乙烯膜压于镍钛合金支架制成人工血管内支架,将其植入实验猪肾下腹主动脉。2、4、12周取材,切片行苏木素伊红(HE)染色、胶原纤维和弹力纤维染色、血管平滑肌细胞α肌动蛋白免疫组织化学检查以及细胞原位凋亡检测,并行图像分析,对照实验组与正常腹主动脉内膜厚度、胶原纤维和弹力纤维相对含量、血管平滑肌细胞密度和凋亡比例。结果实验组2周时人工血管内支架表面有内皮细胞覆盖,与正常组相比,其各时间点内膜增生显著(P<0.01),弹力纤维和胶原纤维的形态和分布基本正常(P>0.05),2、4周时中膜内血管平滑肌细胞密度和凋亡比例显著高于正常组(P<0.01)。结论人工血管内支架与腹主动脉有着良好的生物相容性,但内膜增生较明显。     

他莫昔芬对大鼠腹主动脉瘤形成的抑制作用

目的 观察他莫昔芬对大鼠腹主动脉瘤(AAA)形成的影响及作用机制.方法 40只雄性Wistar大鼠随机分成2组,实验组他莫昔芬预给药7 d(每天15 mg/kg体重),建立A从灌注模制.术后7 d切取腹主动脉.一计算腹主动脉直径变化率,苏木素-伊红(HE)染色观察动脉壁炎性细胞浸润,Verhoff染色观察动脉壁弹性纤维,免疫组织化学观察动脉壁基质金属蛋白酶(MMP)-2,9及巨噬细胞的表达.结果 他莫昔芬明显抑制AAA的形成,抑制率95%～99%.动脉壁内炎性细胞浸润明显减少,弹力纤维破坏受到抑制,MMP-2,9及巨噬细胞的表达受到抑制.结论 他莫昔芬通过抑制大鼠腹主动脉壁内早期的炎症反应和MMPS的表达,抑制大鼠AAA的形成.     

大鼠腹主动脉瘤发生与骨桥蛋白及核因子-κB表达的关系

目的 构建大鼠腹主动脉瘤模型并观察大鼠腹主动脉瘤中骨桥蛋白(OPN)及核因子-κB(NF-κB)的表达,探讨大鼠腹主动脉瘤发生的分子机制.方法 将30只大鼠分为3组,每组10只,用酶灌注法灌注30 min构建大鼠腹主动脉瘤模型;测量动脉直径;苏木素-伊红(HE)染色及特殊染色检测主动脉的结构改变及炎性细胞浸润;免疫组织化学技术、Western blot法检测动脉组织中OPN、NF-κB及基质金属蛋白酶-2(MMP-2)的表达.结果 成功构建大鼠腹主动脉瘤模型;腹主动脉瘤组术后直径扩张率明显高于对照组(P＜0.01),并且中层弹力蛋白明显减少,炎性细胞浸润程度显著增高;免疫组织化学结果显示OPN、NF-κB及MMP-2在腹主动脉瘤组中的表达均明显增加(P＜0.05).Western blot结果同样显示OPN、NF-κB及MMP-2在腹主动脉瘤组中的表达均明显增加(P＜0.01),OPN、NF-κB及MMP-2呈正相关.结论 在大鼠腹主动脉瘤模型中,OPN可能通过NF-κB途径上调MMP-2的表达,进而加速细胞外基质的降解,最终导致主动脉瘤的发生发展.     

内膜下血管成形术动物模型构建后的形态学观察

目的观察内膜下血管成形术（SIA）动物模型构建后血管壁有关组成成分的组织学变化。方法在15头巴马猪颈总动脉建立SIA模型，然后在术后不同时间应用常规苏木素-伊红（HE）染色、维多利亚蓝染色（观察弹力纤维变化）、Masson三色染色（观察胶原纤维变化）、免疫组织化学方法检测α-平滑肌肌动蛋白（α-SMA）及Ⅷ因子（vWF）表达等方法观察造模段动脉的组织细胞学变化。结果SIA术后新的血流通道内表面有内皮细胞覆盖，动脉管壁有新内膜形成，中膜增厚，平滑肌细胞数量增多，较多泡沫细胞出现，胶原纤维及弹力纤维染色范围增大、染色密度增加。超微结构观察提示SIA术后中膜层平滑肌细胞的收缩型与合成型同时存在；细胞外基质中胶原纤维和弹力纤维含量异常丰富。结论SIA模型构建术后的病理组织学改变与腔内血管成形术后基本一致。     

膜型基质金属蛋白酶Ⅰ在胸主动脉瘤中的作用机制研究进展

胸主动脉瘤(thoracic aortic aneurysm,TAA)较常见,是复杂、凶险的心血管疾病.病变通常位于升主动脉,由于动脉管壁中层的平滑肌细胞坏死、弹性纤维变性和黏液样物质沉积,导致主动脉呈瘤样突出,同时在动脉血流的冲击压力下不断膨大,最终形成夹层动脉瘤甚至破裂[1].     

Simultaneous Open and Endoluminal Repair of Ruptured Abdominal and Thoracic Aortic Aneurysms: Report of a Case

A 66-year-old woman was transferred to our hospital for emergency treatment of a ruptured abdominal aortic aneurysm (AAA) and impending rupture of a descending thoracic aortic aneurysm (TAA) caused by a Stanford type-B dissection. She had severe coronary artery disease and a highly calcified aorta, and had been taking long-term steroids for rheumatoid arthritis. Endovascular repair of the TAA failed because the femoral artery was too small, so we performed simultaneous repair of the TAA and the AAA. A temporary axillofemoral bypass was constructed and the AAA was replaced with a bifurcated prosthetic graft. A thoracic stent graft was delivered successfully through a chimney graft of the abdominal graft. About 4 months later, the TAA extended proximally, causing hemoptysis, which was stopped by placing a new stent graft proximal to the previous one. This case report shows that a combination of open and endovascular repair is useful for treating a TAA with an AAA, especially in a small or frail patient.     

A biologic basis for asymmetric growth in descending thoracic aortic aneurysms: a role for matrix metalloproteinase 9 and 2

OBJECTIVE: This study was undertaken to define matrix metalloproteinase (MMP) expression in the anterior and posterior wall of descending thoracic aortic aneurysms (TAAs) and correlate it with specific computed tomography (CT) image sites within the descending thoracic aorta. METHODS: Serial CT images of patients with TAAs were compared with age- and gender-matched normal descending thoracic aortas at levels T4-T12. The mean circumference of the TAAs was 153 mm (n = 12) and 148 mm (n = 11) at T8 and T10, respectively, compared with 75 mm (n = 12) and 75 mm (n = 10) in controls (P < .001). Aortic tissue was collected from a separate set of eight patients undergoing descending TAA resection (processed < or =12 hours of excision) and six cadavers (processed < or =24 hours of death). Tissue collected between the intercostals arteries was defined as posterior wall, and directly opposite was the anterior wall. MMP-9 and MMP-2 messenger RNA (mRNA) extracted from aortic tissue was analyzed by quantitative real time polymerase chain reaction (PCR) and normalized to beta-actin. Immunohistochemistry was performed for MMP-9 and MMP-2. CT aortic measurements and MMP expression were compared by t tests and analysis of variance, respectively. RESULTS: The ratio of arc distance between the intercostals on the posterior wall to total aortic circumference was 0.14 in healthy controls compared with 0.08 in TAAs at vertebral level T8 (P = .001). At T10, the ratio was 0.15 in healthy controls compared with 0.11 in TAAs (P = .001). MMP-9 expression in TAAs was 4.3-fold higher in the anterior wall compared with the posterior wall (P = .03). Conversely, MMP-2 expression in TAAs was 3.2-fold higher in the posterior wall compared with the anterior wall (P = .008). MMP expression was not detected in control cadaver aortas. CONCLUSION: Anterior walls of expanding TAAs grow at a greater rate than the posterior wall, as determined from the lower ratio of intercostal arc distance to total circumference in TAAs. Differential MMP expression appears to be a biologic marker for asymmetric growth in the TAA wall. CLINICAL RELEVANCE: The pathogenesis of thoracic aortic aneurysms (TAAs) is poorly understood. Multiple lines of evidence suggest that matrix metalloproteinases (MMPs), a family of enzymes, are important in aneurysm development. Earlier experiments documented a regional variation of MMP-9 in stimulated rodent aortas, with production greater in the abdominal aorta compared with the thoracic aorta. The present study extends that observation and documents asymmetric aneurysm development in the TAA wall, with increased anterior wall growth in correlation to increased MMP-9 production. An improved understanding of the mechanisms by which MMP production is regulated is critical.     

Differential regulation of the superoxide dismutase family in experimental aortic aneurysms and rat aortic explants

OBJECTIVE: Oxidative stress has been implicated in abdominal aortic aneurysm pathogenesis. This study sought to characterize the relevance of superoxide dismutases (SOD), a family of reactive oxygen catalyzing metalloenzymes, including manganese SOD (MnSOD), copper-zinc SOD (CuZnSOD), and extracellular SOD (EcSOD), in a rodent aortic aneurysm model. METHODS: Male rat infrarenal abdominal aortas were perfused with either saline (control) or porcine pancreatic elastase (6 U/mL). Aortic diameter was measured and aortas harvested on post-operation days 1, 2, and 7 (N=5-6 per treatment group per day). MnSOD, CuZnSOD, EcSOD, catalase, MMP-2, MMP-9, and beta-actin expression in aortic tissue was determined by quantitative real-time PCR. MnSOD protein levels were measured using western immunoblotting and immunohistochemistry. In subsequent experiments, aimed at understanding the mechanism by which SOD is involved in AAA pathogenesis, rat aortic explants (RAEs) were incubated in media for 24 h in the presence of interleukin-1beta (IL-1beta, 2 ng/mL) and TEMPOL (SOD mimetic), catalase, or a combined SOD and catalase mimetic. Media MMP-2 and MMP-9 activity was determined by zymography. Data were analyzed by Student's t-tests and ANOVA. RESULTS: Elastase-perfused aortic diameters were significantly increased compared to control aortas by post-perfusion day 7 (P=0.016). MnSOD mRNA levels in elastase perfused aortas were 6.0 (P=0.05) and 7.5 times (P<0.01) greater than control aortas at post-perfusion days 1 and 2, respectively. EcSOD, CuZnSOD, catalase, and MMP-2 mRNA expression did not statistically vary between the two groups. MMP-9 expression was 3.5-fold higher in the elastase group on post-perfusion day 2 (P=0.04). Western immunoblotting confirmed MnSOD protein was up-regulated on day 4 in the elastase-perfused group compared to controls (P=0.02). Immunohistrochemistry demonstrated increased MnSOD staining in the elastase group on day 4. In RAE experiments, TEMPOL increased both MMP-9 and MMP-2 activity 2 (P=0.09) and 3-fold (P=0.05), respectively, whereas catalase and the combined SOD/catalase mimetic failed to increase MMP-2 or MMP-9 activity. CONCLUSION: Experimental abdominal aortic aneurysm formation is associated with early increases in MnSOD expression and an increase in MMP-9 activity. Strategies aimed at inhibiting oxidative stress during AAA formation should focus on MnSOD.     

Matrix metalloproteinases in ascending aortic aneurysms: bicuspid versus trileaflet aortic valves

BACKGROUND: Abnormal matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase (TIMP) expression contributes to the development of abdominal aortic aneurysms. Recent data suggest that MMP-2 and MMP-9 may also play a role in thoracic aortic disease. We sought to determine (1) whether ascending aortic aneurysms are associated with increased MMP expression and (2) whether aortic inflammation and MMP expression differ between patients with congenital bicuspid aortic valves (BAVs) and those with trileaflet aortic valves (TAVs). MATERIALS AND METHODS: Samples of ascending aortic aneurysms were obtained from 29 patients; 14 patients had BAVs and 15 had TAVs. Control ascending aorta was obtained from 14 organ donors or heart transplant recipients. Aortic histology and immunohistochemistry were performed to evaluate elastin degradation, inflammatory changes, and MMP-2 and MMP-9 expression. Aortic levels of MMP-2, MMP-9, TIMP-1, and TIMP-2 were measured using ELISA. RESULTS: Aneurysms in the TAV patients exhibited marked inflammation, high CD68 expression, diminished elastin content, increased MMP-9 expression, and normal MMP-2 levels. In contrast, BAV aneurysms were characterized by a relative lack of inflammation, preservation of elastin content, normal MMP-9 levels, and elevated MMP-2 expression. TIMP-1 and TIMP-2 levels were not significantly different among the three groups. CONCLUSIONS: Ascending aortic aneurysms exhibited increased MMP expression. The pattern of MMP expression and the degree of inflammation, however, differed between aneurysms associated with BAVs and those with TAVs. Variations in the molecular mechanisms underlying different types of thoracic aortic aneurysms warrant further investigation.