Pathogenesis of abdominal aortic aneurysm – the role of inflammation and proteolysis

Clinical studies show that the morbidity rate for abdominal aortic aneurysms (AAAs) is high, especially among older people. A lack of early diagnosis carries a high risk of fatality. Abdominal aortic aneurysm formation is connected to, among others, inflammatory mediators, proteolytic degradation of the extracellular matrix and genetic predispositions. Additionally, a crucial part of this process is played by the presence of intraluminal thrombus, which participates in the inflammatory reactions and proteolysis contributing to the degradation of the wall’s building elements. Intraluminal thrombus and inflammatory cells’ which infiltrate the vessel wall characterize the pathogenesis of AAA. The dominant population of cells is lymphocytes T and B, neutrophils, monocytes/macrophages, natural killer (NK) cells, as well as mast cells, which produce different inflammatory factors and mediators which contribute to collagen, elastin and smooth muscle cell degradation in the aortic wall. The intensified inflammatory process may lead to increased proteolytic enzyme activity that is necessary for the progression and rupture of the aneurysm. In the presented paper, we show the participation of inflammatory factors in the pathogenesis of AAA and review chosen mediators of inflammation and proteolysis. A better understanding of the immunological mechanisms in the pathogenesis of AAA may help in modulation, innovation, and improvements in methods of treatment.