RNA in blood is altered prior to hemorrhagic transformation in ischemic stroke

Abstract

Objective Hemorrhagic transformation (HT) is a major complication of ischemic stroke that worsens outcomes and increases mortality. Disruption of the blood brain barrier is a central feature to HT pathogenesis, and leukocytes may contribute to this process. We sought to determine whether ischemic strokes that develop HT have differences in RNA expression in blood within 3 hours of stroke onset prior to treatment with thrombolytic therapy. Methods Stroke patient blood samples were obtained prior to treatment with thrombolysis, and leukocyte RNA assessed by microarray analysis. Strokes that developed HT (n=11) were compared to strokes without HT (n=33) and controls (n=14). Genes were identified (corrected p-value <0.05, fold change ≥|1.2|) and functional analysis performed. RNA prediction of HT in stroke was evaluated using cross-validation, and in a second stroke cohort (n=52). Results Ischemic strokes that developed HT had differential expression of 29 genes in circulating leukocytes prior to treatment with thrombolytic therapy. A panel of 6 genes could predict strokes that later developed HT with 80% sensitivity and 70.2% specificity. Key pathways involved in HT of human stroke are described, including amphiregulin, a growth factor that regulates matrix metalloproteinase-9; a shift in transforming growth factor-beta signaling involving SMAD4, INPP5D and IRAK3; and a disruption of coagulation factors V and VIII. Interpretation Identified genes correspond to differences in inflammation and coagulation that may predispose to HT in ischemic stroke. Given the adverse impact of HT on stroke outcomes, further evaluation of the identified genes and pathways is warranted to determine their potential as therapeutic targets to reduce HT and as markers of HT risk.

Blood transcriptome changes after stroke in an African American population

“…Our preliminary data based on gene expression levels suggest an accuracy of 92% (88% sensitivity and >90% specificity). These values are similar to the accuracy obtained by previous microarray studies 6, 8, 23. Using a unique approach of evaluating exon‐specific expression patterns (due to alternative transcript splicing) we obtained a higher normalized accuracy rate of 93%, with 100% specificity.…”

“…As such the application of gene expression analysis, using unbiased application of mathematical cluster analysis to identify stroke subtypes offers promise. Studies of microarrays and NGS show the diagnostic potential of such an approach 5, 6, 7, 8, 10, 23, 24, 25. Using molecular technology, preliminary diagnostic discrimination following stroke is over 90% accurate, with similar high sensitivity and specificity.…”

“…Previous studies using microarrays have set the stage for this technological approach to clinical diagnosis of neurological disorder 5, 6, 8, 15, 23. More recently, the same group published a preliminary RNA‐Seq study 10.…”

Hemorrhagic Transformation after Ischemic Stroke in Animals and Humans

“…75 Early Hemorrhagic Transformation: Role of Other Leukocyte Factors Though leukocyte-derived MMPs appear to be one mediator of early HT, additional leukocyte-derived molecules have been implicated. 76 We examined mRNA expression in blood within 3 hours of ischemic stroke onset in humans before administration of tPA. Twenty-nine genes were differentially expressed in patients that developed HT.…”

“…Six genes predicted HT in a second cohort with 80% sensitivity and 70% specificity. 76 These genes included amphiregulin, membrane-associated ring finger (C3HC4) 7, SMAD family member 4 (SMAD4), inositol polyphosphate-5-phosphatase (INPP5D), multiple coagulation factor deficiency 2 (MCFD2), and vascular endothelial growth inhibitor (Figure 2).…”