Introduction: Endothelial cells (EC) must maintain an effective physiologic barrier in a highly dynamic environment. Capable of regulating other cells within the vasculature (e.g. smooth muscle cells), ECs govern response to injury and inflammation. microRNAs (miR) are emerging as critical regulators of vascular disease, implicating EC miRs in homeostasis maintenance. Increased EC permeability has been documented in atherosusceptible regions of the aorta suggesting it plays a role in disease development, but whether this is a cause or consequence is unknown. Hypothesis: We hypothesized EC barrier dysfunction is a critical event that perpetuates chronic vascular disease via altered miR profiles. Methods: Human aortic endothelial cells (HAEC) cultured in transwells were exposed to thrombin (0.5, 1, 2U/ml) and permeability measured by fluorescence flux across monolayers at 90 minutes. Total HAEC RNA was isolated at various timepoints with individual miR transcripts counted using nanoString nCounter® (n=6 samples). miR that was altered >2-fold compared to controls were analyzed using nSolver ™ software and Ingenuity® Pathway Analysis (IPA). Results: Thrombin exposure increased EC permeability to 130±8.4% of untreated controls (2U/ml thrombin; p<0.05; n=16 transwells). Heatmaps from miR counts showed extensive miR profile changes in response to thrombin (n=6 samples (control, 90min, 4h, 24h)). Using IPA, miRs were clustered based on seed regions and matched with experimentally confirmed mRNA targets. At all timepoints, mRNA targets were shown to be most involved in cancer and injury disease pathways, with top cellular functions identified as cell movement, proliferation, growth, and survival. Conclusions: In response to a permeability insult, HAEC miR levels are significantly altered. Although our preliminary data need to be further substantiated, they highlight a possible mechanism whereby EC barrier dysfunction is a critical event that perpetuates chronic vascular disease. In this way, we might envision a scenario not unlike cancer (which has been compared to atherosclerosis), where an initial appropriate endothelial repair response becomes dysregulated in the context of ongoing injury (e.g. permeability) in atherosusceptible regions.