Matrix metalloproteinases and their tissue inhibitors as indicators of aortic aneurysm and dissection development in extracellular matrix remodeling.

Aneurysms and dissections represent some of the most serious cardiovascular diseases. The prevailing theory posits that mechanical overloading of the vessel wall is the underlying cause. Inspired by Barkhordarian et al, the authors present matrix metalloproteinases (MMPs) and their inhibitors in immunohistological analyses as contributing factors in the pathophysiology of aortic aneurysms (AA). Data analysis of MMP-1, MMP-9, tissue inhibitors of metalloproteinases (TIMPs), including TIMP-1 and TIMP-2 expression reveals a varied distribution between the adventitia and media and a non-uniform expression of the investigated markers. These elements, as key components of the extracellular matrix (ECM), indicate that the formation of AA is not solely driven by endoluminal pressure loading of the aortic wall. Instead, degenerative processes within ECM elements contribute significantly. Importantly, AA do not necessarily imply dissection. Tissue destruction, allowing blood flow entry, arises from reduced oxygen supply to the media, primarily due to incomplete capillarization or neocapillarization.