Thrombus versus wall biological activities in experimental aortic aneurysms

Area of Science:

• Biochemistry
• Vascular Biology
• Protease Activity

Background:

• Intraluminal thrombus (ILT) is implicated in abdominal aortic aneurysm (AAA) development.
• The specific mechanisms by which ILT influences AAA progression remain under investigation.

Purpose of the Study:

• To investigate the role of ILT in AAA evolution by examining its influence on AAA wall biological activity.
• To compare protease and microparticle (MP) levels between ILT and AAA wall in a rat model.

Main Methods:

• Experimental abdominal aortic aneurysms (AAAs) were created in rats via elastase perfusion.
• Intraluminal thrombus (ILT) and AAA wall tissues were cultured to collect conditioned media.
• Gelatin zymography, casein zymography, substrate hydrolysis, and flow cytometry were used to quantify protease and MP levels.

Main Results:

• ILT released higher levels of matrix metalloproteinase-9 (MMP9) compared to the AAA wall.
• Levels of elastase, urokinase plasminogen activator, plasmin, and MPs were elevated in ILT versus the wall.
• Aneurysm diameter correlated positively with wall MMP9, MMP2 activation, plasmin activity, and MP release.

Conclusions:

• The intraluminal thrombus (ILT) may contribute to abdominal aortic aneurysm (AAA) evolution.
• ILT influences AAA progression by modulating the protease activity within the AAA wall.