Houard X, Rouzet F, Touat Z, Philippe M, Dominguez M, Fontaine V, Sarda-Mantel L, Meulemans A, Le Guludec D, Meilhac O, Michel J-B
INSERM U698, Cardiovascular Haematology, Bioengineering and Remodelling, Bichat-Claude Bernard Hospital, 46 Rue Henri Huchard, 75877 Paris Cedex 18, France.
J Pathol. 2007 May;212(1):20-8. doi: 10.1002/path.2148.
Development and progression of acquired abdominal aortic aneurysms (AAAs) involve proteolytic activity. In the present study, we investigate the distribution of fibrinolytic system components within mural thrombi of human AAAs. 20 mural thrombi and the remaining AAA walls were dissected. The luminal, intermediate and abluminal thrombus layers, and media and adventitia were separately incubated in cell culture medium. Conditioned media were then analysed for plasminogen activators (PAs), plasminogen activator inhibitor-1 (PAI-1), free-plasmin, plasmin alpha(2)-antiplasmin complexes (PAPs) and D-dimers release. In parallel, PA and PAI-1 mRNA expression analysis was performed by RT-PCR. The study was completed by immunohistochemical localization of these components in AAA, ex vivo functional imaging using (99m)Tc-aprotinin as a ligand and measurement of PAP and D-dimer plasma levels. All fibrinolytic system components were present in each aneurysmal layer. However, the mural thrombus was the main source of active serine-protease release. Interestingly, the luminal layer of the thrombus released greater amounts of PAPs and D-dimers. This paralleled the preferential immunolocalization of plasminogen and PAs, and the (99m)Tc-aprotinin scintigraphic signal observed in the luminal pole of the thrombus. In contrast, mRNA expression analysis showed an exclusive synthesis of tPA and PAI-1 within the wall, whereas uPA mRNA was also expressed within the thrombus. Taken together, these results suggest that the increased plasma concentrations of PAPs and D-dimers found in AAA patients are related to mural thrombus proteolytic activity, thus explaining their known link with AAA progression. Components of the fibrinolytic system could also represent a target for functional imaging of thrombus activities in AAA.
获得性腹主动脉瘤（AAA）的发生和发展涉及蛋白水解活性。在本研究中，我们调查了人AAA壁血栓内纤维蛋白溶解系统成分的分布。解剖了20个壁血栓和其余的AAA壁。将血栓的管腔层、中间层和外膜层以及中膜和外膜分别在细胞培养基中孵育。然后分析条件培养基中纤溶酶原激活剂（PAs）、纤溶酶原激活剂抑制剂-1（PAI-1）、游离纤溶酶、纤溶酶α2-抗纤溶酶复合物（PAPs）和D-二聚体的释放情况。同时，通过RT-PCR进行PA和PAI-1 mRNA表达分析。通过这些成分在AAA中的免疫组织化学定位、使用（99m）Tc-抑肽酶作为配体的离体功能成像以及测量PAP和D-二聚体血浆水平完成了该研究。所有纤维蛋白溶解系统成分均存在于每个动脉瘤层中。然而，壁血栓是活性丝氨酸蛋白酶释放的主要来源。有趣的是，血栓的管腔层释放了更多的PAPs和D-二聚体。这与纤溶酶原和PAs的优先免疫定位以及在血栓管腔极观察到的（99m）Tc-抑肽酶闪烁扫描信号平行。相比之下，mRNA表达分析显示壁内仅合成tPA和PAI-1，而uPA mRNA也在血栓内表达。综上所述，这些结果表明，在AAA患者中发现的血浆PAPs和D-二聚体浓度升高与壁血栓蛋白水解活性有关，从而解释了它们与AAA进展的已知联系。纤维蛋白溶解系统的成分也可能代表AAA中血栓活动功能成像的靶点。
