CD40配体加重内皮损伤介导的炎症反应及其在主动脉瘤发病与进展中的作用机制研究

Inflammation mediated by endothelial cell injury is a key mechanism for aortic aneurysm formation. Our previous studies have shown that inhibition of platelet activition and aggregation with pharmacotherapy could prevent the development of aortic aneurysm. However, the initiators of the platelet activition and aortic aneurysm progression have not been clearly defined.Recent studies have demonstrated that CD40 ligand is an important inflammatory cytokine released by platelets.It could impair the function of endothelial progenitor cells and inhibit endothelial healing after arterial injury. Based on these findings, we hypothesized that CD4O ligand may play an important role via mechanisms such as influencing the function of endothelial progenitor cells and promoting inflammation mediated by endothelial cell injury. We will use angiotensin II induced aortic aneurysm mice model constructed on CD40 ligand knock out mice and human aortic aneurysm samples in this study. The experimental techniques involving include pathology staining, immunohistochemistry,cells adhension and transmigration both in vivo and in vitro. With human aortic aneurysm samples, we will define the relationship between CD40 ligand and aortic aneurysm formation in human. We seek to verify the mechanism and the role played by CD40 ligand in the development of aortic aneurysm, and provide a new target for clinical treatment of aortic aneurysm.

内皮细胞损伤介导的炎症反应是促使主动脉瘤发病的重要病理机制。本课题前期研究发现：通过药物阻止血小板活化与聚集可以抑制主动脉瘤发病，但血小板促使主动脉瘤发病的机制尚不明确。已有研究证实CD40L是血小板释放的重要炎症因子，其可以抑制内皮祖细胞功能，阻止内皮损伤修复。据此，本研究提出假设：CD40L可以通过抑制内皮祖细胞功能，加重内皮损伤介导的炎症反应，促使主动脉瘤的发病及进展。本研究拟在血管紧张素II诱导的主动脉瘤模型上，采用CD40L基因敲除小鼠，利用病理分析、免疫组化、细胞粘附、迁移等体内、体外实验技术，观察CD40L对主动脉瘤发病、血管内皮损伤、氧化应激、炎症反应、内皮祖细胞功能的作用，同时结合临床样本分析、随访研究，阐明CD40L与人主动脉瘤发病及进展的关系作用，从而明确CD40L通过加重内皮损伤介导的炎症反应，促使主动脉瘤发病及进展的作用及机制，以期为主动瘤的临床治疗提供新靶点。

背景：主动脉瘤是一种严重的大血管疾病，95%的患者在发病初期可无明显症状，而随着病情的进展，会发展成为主动脉夹层，其中 StanfordA 型主动脉夹层未经治疗的一个月内死亡率高到 70%，目前除了外科手术没有更好地治疗方案，如何及时诊断及争取手术时机是困扰临床医生的一个难题。能否找到一个细胞因子能够帮助诊断，甚至能延缓主动脉夹层破裂死亡还是为未知数，CD40L是否在主动脉夹层中也有作用，成为预测因子还是个未知数。.研究内容：本研究的目的是探讨CD40L(cluster of differentiation 40L)如何影响血管内皮损伤介导的炎性反应以及与Stanford A型主动脉夹层发病之间的关系。.结果：STAAD患者100例，年龄为48.31±11.97岁,男性占70%， 健康体检共139例48.84±9.98岁，男性占70.50%。与健康体检人群对比，STAAD组 SCD40L(p<0.001)有明显的升高。E-Selectin(p<0.001)，VCAM-1 [vascular cell adhesion molecule 1])；炎性指标IL-1β(p<0.001), IL-6(p <0.001), TNF-α(p <0.001)明显升高。小鼠实验：实验发现B组小鼠死亡率高（21只77.78% ），死亡小鼠解剖发现出现心包填塞，部分小鼠有主动脉夹层发生，存活小鼠部分有动脉瘤与B组进行对照分析，其中D组中SCD40L（p <0.01）,IL-1β（p <0.01）,IL-2（p <0.01），IL-6（p <0.01）,TNF-α（p <0.01）等炎性介子指标升高降低，P-Selectins（p <0.01）TM(p <0.01）等提示血管内皮损伤的指标也明显降低。细胞划痕实验中人脐静脉内皮细胞在添加重组人可溶性CD40配体比未添加重组人可溶性CD40配体划痕区明显增宽。.CD40L加重血管内皮损伤介导的炎性反应促使主动脉夹层发生，CD40L 可以作为急性主动脉夹层的预测因子进行临床转化。