Abstract TP76: Combined MRI and Next Generation Sequencing of mRNA in Acute Ischemic Stroke Patients Reveal a Correlation Between Early Changes in Infarct and Angiogenesis

Abstract

We previously showed that early changes in infarct volume (ECS) perform better as a predictor of early neurologic outcome in acute ischemic stroke (AIS) patients receiving thrombolysis when compared to percent recanalization (PER) and infarct volume at 24 hours (InVol), but the biologic explanation is unclear. We combined MRI and RNA Seq to compare the biologic associations. Methods: Pretreatment, 2-, and 24-hours post-thrombolysis MRIs were analyzed in 15 enrolled AIS patients treated with thrombolysis. ECS on the apparent diffusion coefficient sequence and PER on the perfusion scan were measured by comparing the pretreatment and 2-hour post thrombolysis MRI using automated co-registered MRI sequences within a region of interest defined by a > 4 second delay in time-to-peak on perfusion imaging using Matlab. InVol was measured on diffusion weighted images by a blinded reviewer. Blood samples were collected 2-hours and 24-hours post thrombolysis. RNA Seq was performed with HiSeq 25000 Illumina platform. After correcting for age, gender, and race, “leave one out testing” was used to select mRNA that correlated with the imaging variables (FDR corrected P-value < 0.05). Results: PER only correlated with 2 mRNA from 2-hour blood. InVol was associated with 20 mRNA from 24-hour blood. Both lacked significant disease and function associations. ECS correlated with 24 mRNA from 2-hour blood, with significant association with a decrease in IPA Ingenuity disease and functions annotations for both development of vasculature (P=0.005, Z-score -2.2) and angiogenesis (P=0.02, Z-score -2.2). Interestingly, IPA annotations for vascular development and angiogenesis include epoxyeicosatrienoic acid, a mediator of neurovascular coupling induced by cerebral ischemia, and degraded by soluble epoxide hydrolase enzyme (SEH). SEH inhibitor 12-(3-adamantan-1-yl-ureido) dodecanoic acid (AUDA) was a potential upstream regulator (P=5.03E-04), and AUDA has previously been shown to reduce infarct size in an animal model of ischemic stroke. Here we demonstrate the benefit of the combined MRI/blood biomarkers approach for elucidating biologic responses in AIS in identifying potential novel new therapeutics in humans, such as the epoxyeicosatrienoic pathway.