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Abstract

Introduction: Ischemic preconditioning is a promising strategy to prevent acute kidney injury causd by ischemia/reperfusion injury. We set out to determine if ischemic preconditioning protects glomerular endothelial cell (GenC) monolayers from a model of ischemia/reperfusion injury (IRI) and whether prolonged hyperglycemia alters the effects of ischemic preconditioning. Hypothesis: We hypothesized that ischemic preconditioning would protect GenC integrity in an in vitro model of IRI, and that this effect would be unchanged in the setting of prolonged hyperglycemia. Methods: GenC were cultured on transwells in normoxia and either normoglycemic (5.5 mM glucose) or hyperglycemic (25.5 mM glucose) conditions. After 5 days of culture, GenC were subjected to either 60 minutes ischemic preconditioning (oxygen-glucose deprivation, OGD) or sham. GenC were returned to normoxia/normoglycemia for 18h. Both preconditioned and control groups of GENC were then exposed to OGD for 6 hours followed by 18 hours of reoxygenation/glucose repletion. Transendothelial electrical resistance (TEER) was used as a measure of GenC monolayer integrity, and was assessed prior to OGD and after reoxygenation/glucose repletion. Statistical analysis was performed using 2-tailed Student’s t-test. Results: The normoglycemic GenC monolayers exposed to ischemic preconditioning were more resistant to OGD than unconditioned gENC as measured by higher TEER values (p=0.02, n= 6). When GenC were cultured in hyperglycemia prior to experimentation, the effect of ischemic preconditioning was lost, and there was no significant difference in TEER values (p=0.68, n=3). Conclusions: These data suggest that ischemic preconditioning protects the integrity of healthy GenC monolayers in an in vitro model of ischemia reperfusion. However, it appears that the protective effect of ischemic preconditioning is lost in cells that are cultured in hyperglycemic conditions. Supported by awards from the Foundation for Anesthesia Education and Research (KJS), Collins Medical Trust (KJS), and K08DK090754-01 (MPH).