A novel pathomechanism in the progression of human abdominal aortic aneurysm

What is it about?

Our findings provide the first demonstration of a causative link between oxidative stress instigating proteolytic enzyme expression at the tissue level and human abdominal aortic aneurysm (AAA) development. Reactive oxygen species can activate matrix metalloproteinase-9 (MMP-9) in areas of high oxidant stress within AAA wall and could therefore contribute to enhanced extracellular matrix degradation. Distribution of oxidative stress and proteolytic expression exists simultaneously within the aortic media and is correlated specifically with intraluminal thrombus (ILT) thickness during aneurysm development. Overall, oxidative stress has been enhanced within the thin thrombus-covered wall. Particularly, oxidative stress and proteolytic expression has been increased within the thin thrombus-covered part of the inner media as well as within the outer media of wall covered by thick thrombi. These observations provide new directions for future research into AAA pathogenesis to study the role of ILT confirmed here, as well as to improve understanding of the role of oxidative stress in aneurysm development and rupture.

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Why is it important?

Our findings show that the presence of a thin circumferential intraluminal thrombus should always be considered as a risk factor for the greatest increase in aneurysm growth rate and rupture, giving an indication for surgery timing.

Perspectives