Using Extracellular Vesicles Isolated from Intracranial Blood to Understand the Local Ischemic Environment and Predict Outcome in Patients Undergoing Mechanical Thrombectomy.

Section I: Title and Summary of Research Proposal Title: Using extracellular vesicles isolated from intracranial blood to understand the local ischemic environment and predict outcome in patients undergoing mechanical thrombectomy. Summary of Research Proposal: Mechanical thrombectomy and intravenous tissue plasminogen activator (tPA) are ischemic stroke treatments that assist in restoring blood flow to the brain tissue, but do not address or treat the degenerative neurovascular cascades initiated during ischemia. The ability to detect alterations in cellular microenvironments occurring distal to the thrombus by studying extracellular vesicles (EVs) is an invaluable biomarker. Cargo contained on and within EVs are quickly emerging as biomarkers to detect both injury and recovery mechanisms. EVs are small (30-150 nm) lipid-bound particles released from most, if not all, cells as a means of carrying lipids, proteins, and nucleic acids (i.e., DNA, mRNA, and non-coding RNA) from one cell to another. Surface markers on the EVs are used determine their cellular origin and provide a snap shot of current cellular milieu. EV cargo is uniquely packaged based on stimuli for that cell. Utilizing banked human samples from the “Blood And Clot Thrombectomy And Collaboration (BACTRAC)” study allows us to look at cell specific biomarkers released immediately distal to the clot during an ischemic stroke. We hypothesize that EVs from the major cells of the neurovascular unit (neurons, astrocytes and endothelial cells) will provide a better understanding of the local ischemic environment and could predict outcomes following stroke. In this proposal we will determine the type of cells that are releasing EVs in the blood distal to the clot (aim 1). We will also analyze proteins contained within the EVs to determine their clinical relevance at predicting stroke outcomes (aim 2). We hypothesize that one protein ratio of interest (BDNF:proBDNF) contained within EVs from neurons will predict NIH Stroke Scale (NIHSS) with dominant side infarcts. Higher infarct times/minutes from last known normal would correlate to increased IL-6 levels in EVs from astrocytes and increased angiogenic markers (i.e., VEGF) in EVs from endothelial cells. The SNIS Joe Nieko Research Grant will provide funding to collect preliminary data for future grant applications that will use cell specific biomarkers for stroke progression and outcomes, creating a variety of translational applications to be explored.