Intracranial aneurysm (IA) is a disease characterized by an abnormal enlargement of the vessel lumen. It is a common pathology with a prevalence of 2-3% in the adult population. IAs are mostly small, quiescent and asymptomatic; yet upon rupture severe brain damage or even death is frequently encountered. Little is known about the etiology of IAs. Actually, their evolution is hard to predict and intricate medical decision. It is thus fundamental to better understand the physiopathology of IAs. It is generally assumed that the initiation, growth and rupture of IAs result from reciprocal action between the composition of the arterial wall and the hemodynamic forces to which it is exposed. In this thesis, I described the histopathological features of IAs prone to rupture. In addition, I investigated how wall shear stress induced by flowing blood and cyclic circumferential stretch incited by pulse waves influence the behavior of vascular endothelial cells.