An aneurysm is a permanent dilation, or ballooning, of a blood vessel or an artery to 1.5 times its normal diameter. It is usually a complication of atherosclerosis, a form of cardiovascular disease where the interior walls of blood vessels are blocked by a fatty substance called plaque. While most aneurysms are small, slow growing and rarely rupture, some are large, fast growing and at higher risk of rupturing. Aneurysm formation can result in hemorrhaging and death if not immediately repaired – the mortality rate after a rupture is 80-90 per cent. Aneurysms in the brain (cerebral aneurysms) can rupture and cause bleeding within the brain, resulting in a stroke. Ciara Chamberlain is studying a protease, Granzyme B, which is made and released by certain types of immune cells. Granzyme B may play a role in aortic aneurysms by breaking down structural proteins and causing thinning of the blood vessel wall. Building upon work in this area already conducted at the James Hogg iCAPTURE Centre, this research seeks to provide definitive evidence about the therapeutic potential for Granzyme B inhibition for the prevention of aneurysms in patients with mild or advanced atherosclerosis.