Indomethacin Prevents the Progression of Thoracic Aortic Aneurysm in Marfan Syndrome Mice.

Background: Marfan syndrome (MFS), an inherited disorder of connective tissue characterized by abnormalities in the skeletal, ocular, and cardiovascular systems, is caused by mutations in the gene for fibrillin-1 (FBN1). The high mortality in untreated patients is primarily due to aneurysm and dissection of the ascending aorta. The complex pathogenesis of MFS involves changes in transforming growth factor β (TGF-β) signaling, increased matrix metalloproteinase (MMP) expression, and fragmentation of the extracellular matrix. A number of studies have demonstrated increased counts of macrophages and T cells in the ascending aorta of persons or mouse models of MFS, but the efficacy of anti-inflammatory therapy in mouse models of MFS has not yet been assessed.

Methods: FBN1 underexpressing mgR/mgR Marfan mice were treated with oral indomethacin. Treatment was begun at the age of three weeks and continued for 8 weeks, following which the aorta of wild type as well as treated and untreated mgR/mgR mice was compared.

Results: Indomethacin treatment led to a statistically significant reduction of aortic elastin degeneration and macrophage infiltration, as well as a lessening of MMP-2, MMP-9, and MMP-12 upregulation. Additionally, indomethacin decreased both cyclooxygenases 2 (COX-2) expression and activity in the aorta of mgR/mgR mice. COX-2-mediated inflammatory infiltrate contributes to the progression of aortic aneurysm in mgR/mgR mice, providing evidence that COX-2 is a relevant therapeutic target in MFS-associated aortic aneurysmal disease.

Conclusions: COX-2 mediated inflammatory infiltration plays an important role in the pathogenesis of aortic aneurysm disease in MFS.