The aim of this thesis is to evaluate the effect of doxycycline on the proteolytic and inflammatory processes in abdominal aneurysms. This data is essential for the development of pharmaceutical strategies for the stabilization of an AAA. Such an approach could reduce the need for elective surgery and endovascular repair. It has repeatedly been shown that AAA progression and rupture is related to the failure of collagen in the aortic wall. Yet the exact mechanism underlying this failure remains unknown. Furthermore, the precise mechanism of activation of collagenases and their inflammatory mediators that are responsible for the collagen turnover of AAA are unknown. In this thesis we attempt to determine how collagen metabolism is balanced in aneurysmal diseases and contribute to the knowledge which collagenases and inflammatory mediators are involved in the destruction of the collagen network in AAA disease. Moreover, we evaluate some of the effects of doxycycline on the proteases and inflammatory mediators in AAA. Analyses showed that doxycycline inhibits specific MMPs and inflammatory pathways that are involved in the collagen balance and aneurysm growth. Together, these observations provide a rationale for a randomized clinical trial studying the effect of doxycycline on aneurysm growth.HartstichtingUBL - phd migration 201