One study conducted on a population with thoracic aortic aneurysm who underwent surgery revealed that the aortic specimens of these individuals were abundant in MMP-1 and MMP-9 expression, whereas TIMP-1 and TIMP-2 were barely expressed, and were more easily detectable towards the outer layers of the vessel [51]. This evidence concerns the gene MMP1 and thoracic aortic aneurysm.