Analysis of microRNA signatures in ischemic stroke thrombus

We investigated the microRNA expression pattern from thrombus retrieved by mechanical thrombectomy in acute stroke patients to understand the stroke mechanism.This study included acute ischemic stroke patients who had undergone intra-arterial thrombectomy at Chung-Ang University Hospital in Seoul, Korea between February 2016 and March 2019. The thrombus was retrieved and stored at -70℃ after obtaining informed consent. MicroRNA microarray analysis was performed for the patients with identified stroke mechanisms including (1) large artery atherosclerosis, (2) cardioembolism with atrial fibrillation, and (3) cardioembolism with valvular heart disease. The microRNAs derived from microarray analysis were validated by quantitative real-time polymerase chain reaction (qRT-PCR) from different patient populations. The correlation analysis was performed between microRNA levels and laboratory data to understand the functional relevance of the altered microRNA.In total, 55 thrombi were obtained from 74 patients, and the microRNAs were analyzed in 45 samples. Microarray analysis of 2578 microRNAs revealed that 50 microRNAs were significantly altered among the three groups. Validation using qRT-PCR showed that miR-378f and miR-450b-5p were significantly elevated among the cardioembolic thrombi; both microRNAs were inversely correlated with the ejection fraction from echocardiography. Thrombi from patients with early neurological deterioration exhibited higher levels of miR-93-5p and lower levels of miR-629-5p than those from neurologically stable patients.The microRNA expression pattern can provide information regarding the mechanism of stroke by reflecting the underlying pathological status of the organ from which the thrombus was derived.