The role of leukocytes in the formation and rupture of intracranial aneurysms

Ruptured intracranial aneurysms (IAs) affect a small proportion of the population; however, the morbidity and mortality is disproportionally high. Although little is known about IA formation, progression, and rupture, mounting evidence suggests that inflammation may play an important role in IA pathogenesis. There is emerging evidence to suggest that leukocytes play a key role in generating and maintaining a pathologic inflammatory response that leads to aneurysm formation and rupture. We present the current literature pertaining to the role of leukocytes in aneurysm formation, progression, and rupture. The contributions of individual cell types are detailed, with special attention paid to the cytokine and molecular profiles. The role of magnetic resonance imaging as a means by which to evaluate aneurysm-associated inflammation is reviewed. Finally, we discuss leukocytes as potential targets of pharmacologic intervention.