TNF and aneurysm: The goals of the present study were to: 1) assess the direct role TNF-α in a model of cerebral aneurysm formation; 2) determine if there are alterations in TNF-α expression in cerebral aneurysm formation and rupture; 3) evaluate if TNF-α inhibition decreases the incidence of aneurysm formation; and 4) test whether TNF-α inhibition after cerebral aneurysm formation may lead to aneurysm stabilization and inhibition of rupture.