Matrix metalloproteinase levels in chronic thoracic aortic dissection.

Area of Science:

• Cardiovascular Biology
• Proteomics
• Aortic Disease Research

Background:

• Imbalance between matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) is implicated in aortic wall failure.
• Chronic descending thoracic aortic dissection can lead to aneurysms due to extracellular matrix degradation.

Purpose of the Study:

• To investigate tissue and plasma levels of specific MMPs and TIMPs in patients with aneurysms from chronic descending thoracic aortic dissection.
• To determine if MMP and TIMP levels correlate with aortic dissection and aneurysm development.

Main Methods:

• Aortic tissue and plasma samples were collected from patients with descending thoracic aortic aneurysms and organ-donor controls.
• Levels of MMP-1, -2, -3, -9, -12, -13 and TIMP-1, -2 were measured using various assays and confirmed by Western blot and immunohistochemistry.
• Plasma levels of MMP-3, -9, and -12 were compared between patients and controls.

Main Results:

• Dissection tissue showed higher total MMP-1, total MMP-9, and active MMP-9, with lower total MMP-2 compared to controls.
• Elevated MMP-9 to TIMP-1 and active to total MMP-2 ratios, and a lower MMP-2 to TIMP-2 ratio were observed in dissection tissue.
• Patients exhibited higher plasma active to total MMP-9 ratios; age and hypertension correlated with increased MMP levels.

Conclusions:

• Elevated MMPs and MMP to TIMP ratios in aortic tissue suggest a pro-proteolytic environment contributing to extracellular matrix destruction and medial degeneration post-dissection.
• An increased active to total MMP-9 ratio in plasma may serve as a biomarker for end-stage aneurysm development in chronic thoracic aortic disease.