Influence of intraluminal thrombus on structural and cellular composition of abdominal aortic aneurysm wall
Influence of intraluminal thrombus on structural and cellular composition of abdominal aortic aneurysm wall
复制标题
DOI：
10.1016/s0741-5214(03)00791-2
复制
发表时间：
2003-12-01
影响因子：
4.3
通讯作者：
Swedenborg, J
中科院分区：
文献类型：
--
作者：
Kazi, M;Thyberg, J;Swedenborg, J
导读：有研究认为腹主动脉瘤（AAA）腔内血栓会影响下壁血管。动脉瘤的扩大与血栓的生长有关，并提出在出血进入血栓后发生破裂。为了研究血栓如何影响血管壁，我们比较了被血栓覆盖的动脉瘤壁和暴露于流动血液的壁段的形态。材料和方法。16名患者（14名男性，2名女性，年龄56-79岁）接受选择性AAA修复，其中计算机断层扫描显示血栓和动脉瘤壁段暴露于流动血液中，纳入研究。取动脉瘤标本进行光镜和电镜观察。Masson三色染色用于壁厚测定和胶原蛋白的显示，Weigert-van Gieson染色用于弹性蛋白的显示。通过免疫组化分析细胞组成，抗体分别针对T细胞CD3、T辅助细胞CD4、T细胞毒性细胞CD8、B细胞CD20、巨噬细胞CD68和平滑肌a-肌动蛋白（SMCs）。采用Caspase-3染色和TUNEL分析评价细胞凋亡情况。被血栓覆盖的动脉瘤壁较薄，弹性蛋白纤维较少，少量发现的弹性蛋白纤维常呈碎片状。这部分壁比暴露于流动血液的壁含有更少的SMCs和更多的凋亡核。在动脉瘤壁介质中检测到炎性细胞簇，在血栓覆盖的部分检测到较多的炎性细胞簇。电镜显示无血栓的动脉瘤壁含有致密的胶原基质和分化的SMCs。在被血栓覆盖的部分，SMCs更多的是去分化（合成）和凋亡或坏死。在细胞凋亡的各个阶段，与SMCs密切接触的炎症细胞数量也有所增加。结论：被血栓覆盖的动脉瘤壁较薄，炎症、SMCs凋亡和细胞外基质降解的迹象更为频繁。这些发现提示血栓的形成和炎症细胞的积聚可能会扰乱血管壁的结构完整性和稳定性，从而增加动脉瘤破裂的风险。
Introduction: It has been suggested that the intraluminal thrombus of abdominal aortic aneurysm (AAA) affects the underlying vessel wall. Aneurysm enlargement has been associated with growth of thrombus, and rupture has been proposed to occur after bleeding into the thrombus. To examine how thrombus affects the vessel wall, we compared the morphology of aneurysm wall covered with thrombus with wall segments exposed to flowing blood.Material and methods. Sixteen patients (14 men, 2 women; age range, 56-79 years) undergoing elective repair of AAA, where computed tomography scans showed thrombus and segments of the aneurysm wall exposed to flowing blood, were included in the study. Specimens from the aneurysm were taken for light and electron microscopy. Masson trichrome staining was performed for wall thickness determination and demonstration of collagen, and Weigert-van Gieson staining for elastin. The cellular composition was analyzed by immunohistochemistry with antibodies against CD3 for T cells, CD4 for T helper cells, CD8 for T cytotoxic cells, CD20 for B cells, CD68 for macrophages, and smooth muscle a-actin for smooth muscle cells (SMCs). Caspase-3 staining and TUNEL analysis were performed to evaluate apoptosis.Results. The aneurysm wall covered with thrombus was thinner and contained fewer elastin fibers, and the few that were found were often fragmented. This part of the wall also contained fewer SMCs and more apoptotic nuclei than the wall exposed to flowing blood. Clusters of inflammatory cells were detected in the media of the aneurysm wall and in higher numbers in the parts covered with thrombus. Electron microscopy showed that the aneurysm wall without thrombus contained a dense collagenous matrix with differentiated SMCs. In the segment covered with thrombus, SMCs were more dedifferentiated (synthetic) and apoptotic or necrotic. There were also an increased number of inflammatory cells located in close contact with SMCs in various stages of apoptosis.Conclusion: The aneurysm wall covered with thrombus is thinner and shows more frequent signs of inflammation, apoptosis of SMCs, and degraded extracellular matrix. These findings suggest that thrombus formation and accumulation of inflammatory cells may perturb the structural integrity and stability of the vessel wall and thereby increase the risk for aneurysm rupture.