Presenter: Sarah Johnson
Mentor: Chris Minson
Poster: 19
Major: Biology
Ischemic-reperfusion (I/R) injury is a common complication in which tissues reperfused after an ischemic period experience further damage and dysfunction. Activation of endothelial cells (EC) produces excessive oxygen radicals and triggers vascular inflammation, cellular stress and apoptotic activation, which contribute to the pathophysiology of I/R injury. AMP-activated protein kinase (AMPK) stimulation has been shown to reduce I/R injury following coronary ligation, though the mechanism and cell specificity are unclear. Therefore, we hypothesize AICAR, an adenosine mimetic previously shown to activate AMPK, will promote cytoprotective pathways in ECs, reduce stress and attenuate apoptotic activity under hypoxic stress. To model ischemia, human umbilical vascular endothelial cells (HUVECs) were cultured at physiological normoxic or hypoxic (8 / 1% O2) conditions and treated with AICAR (0.2, and 2mM). Cell protein and media were collected for further analysis. AICAR increased (p<0.05) pAMPKα/AMPKα in hypoxic conditions, but not in normoxia. AICAR pretreatment (2mM, 1hr) and subsequent exposure hypoxia (24hr) showed decreased (p<0.05) BiP expression and cell-adhesion molecule ICAM-1 compared to normoxic control. AICAR reduced (p<0.05) cellular metabolic activity measured by MTT assay in both 8% and 1% O2. Further, reduced ET-1 secretion (p<0.05) followed AICAR treatment (434 ±14 vs. *179 ±1pg/mL). Endothelial permeability increased (p<0.05) with AICAR at 12 (869%) and 24 hours (315%) compared to controls. These data suggest that through AMPK activation, 1 hour treatment with AICAR slows cellular metabolic activity which reduces cell stress and apoptotic activity, and could be a novel modality for prevention of I/R injury in various reperfusion models such as coronary, transplanted tissue models, and vascular disease. Further in vivo studies are needed to assess these promising in vitro results.