Thrombus versus Wall Biological Activities in Experimental Aortic Aneurysms

Abstract

Background/Aim: The intraluminal thrombus (ILT) is considered to participate in abdominal aortic aneurysm (AAA) evolution. To assess whether this role proceeds via ILT influence on biological activity of the AAA wall, we studied the relationships between the levels of some relevant proteases and microparticles (MP) released by ILT versus wall in rat experimental AAAs. Methods and Results: Two weeks after elastase perfusion, ILT and AAA wall were incubated in cell culture medium and studies were performed on conditioned media. As shown by gelatin zymography, ILT released higher amounts of MMP9 than the wall, whereas the level of MMP2 activation (active/pro) was similar. Levels of elastase and urokinase plasminogen activator, plasmin and MPs, determined, respectively, by casein zymography, substrate hydrolysis and flow cytometry, were higher in ILT than in wall. Aneurysm diameter positively correlated with wall MMP9 levels, MMP2 activation, plasmin activity and MP release. Moreover, wall and ILT levels of pro- and active forms of MMP2, elastase and plasmin were positively correlated. Wall levels of MMP2 activation and plasmin activity also correlated with ILT weight. Conclusion: The present data suggest that, in this experimental model, ILT may contribute to AAA evolution via its influence on the level of aneurysmal wall protease activity.

Intra-Aneurysmal Thrombosis as a Possible Cause of Delayed Aneurysm Rupture after Flow-Diversion Treatment

“…17 The volume of mural thrombus correlates with protease activity both in the thrombus itself and within the aneurysm wall, 18 suggesting that the bigger the thrombus, the more important its biochemical effects.…”

Role of Proinflammatory CD68 + Mannose Receptor − Macrophages in Peroxiredoxin-1 Expression and in Abdominal Aortic Aneurysms in Humans

“…8 The secretome, proteome, or transcriptome might also be good targets for identifying biomarkers, either from whole-aorta tissue [9][10][11][12][13] or from the AAA-separated layers. 14,15 However, because AAA is a complex disease, and aneurysmal tissue is similarly complex, proteomic analyses of whole-organ AAA tissue can hide cell-specific targets. Sho et al 16 reported that analysis for cell types in an experimental rat model of AAA reveals specific cellular responses to inflammation that are not shown on whole-aorta tissue.…”

Radiolabeled Fucoidan as a P-Selectin Targeting Agent for In Vivo Imaging of Platelet-Rich Thrombus and Endothelial Activation

“…The model was induced under general pentobarbital (4 mg/100 g of body weight) anesthesia by in situ intraluminal pressurized perfusion of pig pancreatic elastase (3 units, E1250 [Sigma], 1-h perfusion) within an isolated segment of the abdominal aorta. This model is characterized by a biologically active intraluminal thrombus (21,22). Imaging was performed 15 d later.…”