Abstract TMP28: Aspirin Attenuates Inflmmation in the Wall of Human Cerebral Aneurysms

Abstract

Background: Inflammatory cells and molecules play a critical role in formation and rupture of cerebral aneurysms. Recently, an epidemiologic study reported that aspirin decreases the risk of aneurysm rupture. The goal of this study was to determine effects of aspirin on inflammatory cells and molecules in the wall of human cerebral aneurysms, using radiographic and histological techniques. Methods: Ten prospectively enrolled patients harboring 11 unruptured intracranial aneurysms were randomized into aspirin -treated (81 mg daily) and untreated (control) groups. Aneurysms were imaged at baseline using ferumoxytol-enhanced MRI to estimate uptake by macrophages. After three months, all 10 patients were re-imaged before undergoing microsurgical clipping. Aneurysm tissues were collected for immunostaining with monoclonal antibodies for cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), microsomal prostaglandin E2 synthase-1 (mPGES-1) and macrophages. Results: A decrease in signal intensity on ferumoxytol-enhanced MRI was observed after three months of aspirin treatment. Expression of COX-2 (but not COX-1), mPGES-1, and macrophages was lower in the aspirin group than the control group. Conclusion: This study provides radiographic and histological evidence that aspirin attenuates the inflammatory process in the wall of human cerebral aneurysms.