Abstract TP553: Early Elevation of MicroRNA-15a is Associated With Development of Delayed Cerebral Ischemia After Subarachnoid Hemorrhage

Abstract

Backgrounds: Delayed cerebral ischemia (DCI) is a major determinant of prognosis in patients with subarachnoid hemorrhage (SAH). However, little is known about the role of microRNAs (miRNAs) in the development of DCI after SAH. We investigated the expression profile of miRNAs and the chronological changes in the expression of microRNA-15a (miR-15a) in the plasma and cerebrospinal fluid (CSF) of SAH patients. Methods: Peripheral blood and CSF samples were collected from eight aneurysmal SAH patients and three controls without SAH. Exosomal miRNAs were isolated and subjected to microarray analysis with the 3D-gene miRNA microarray kit. The time course of the expression of miR-15a was analyzed using quantitative real-time PCR. Then, blood sample collected at day 1 and 5 from 17 SAH patients with DCI and 15 without DCI were analyzed using quantitative real-time PCR. Results: Microarray analysis demonstrated that 12 miRNAs including miR-15a were up- or down-regulated both in the CSF and plasma after SAH within three days. Quantitative real-time PCR revealed that miR-15a expression was significantly increased in both the CSF and plasma, with a peak around 3 to 5 days after SAH. Furthermore, the plasma level of miR-15a in patients with DCI was significantly elevated on day 5, while it remained unchanged in those without DCI. Conclusions: Our results suggest that an early increase in miR-15a may contribute to development of DCI after SAH.