Prolyl-hydroxylase inhibition preserves endothelial cell function in a rat model of vascular ischemia reperfusion injury Running Title: Prolyl-hydroxylase inhibition preserves endothelial function Section: Cardiovascular Text pages: 23 Number of tables: 1

Abstract

List of non-standard abbreviations: PHD: prolyl-hyroxylase-domain containing enzyme, DMOG: dimethyloxalylglycine, HO-1: heme-oxygenase-1, HIF: hypoxia inducible factor, 2-OG: 2-oxoglutarate, ROS: reactive oxygen species, VSMC: vascular smooth muscle cell, IR: ischemia-reperfusion We investigated endothelium-dependent and -independent vasorelaxations. To simulate IR-injury hypochlorite (NaOCl) was added during warm reperfusion. VSMCs were incubated in NaCl or DMOG solution at 4ºC for 24h after the medium was changed for a supplied standard medium at 37ºC for 6h. Apoptosis was assessed by the TUNEL-method. Gene expression analysis was performed by quantitative real-time PCR. Cold ischemic preservation + NaOCl induced severe endothelial dysfunction, which was significantly improved by DMOG supplementation (maximal relaxation of aortic segments to acetylcholine: control 95±1 vs. NaOCl 44±4 vs. DMOG 68±5%). Number of TUNELpositive cell nuclei was significantly higher in the NaOCl-group and DMOG-treatment significantly decreased apoptosis. Inducible heme-oxygenase 1 mRNA expressions were significantly higher in the DMOG group. Pharmacological modulation of oxygen sensing system by DMOG in an in vitro model of vascular IR effectively preserved endothelial function. Inhibition of PHDs could be therefore a new therapeutic avenue for protecting endothelium and vascular muscle cells against IR-injury