366 Plasma NOx Decreases Following Continuous Flow Left Ventricular Assist Device Despite Lack of Change in Shear Stress

Purpose: Left ventricular assist devices (LVAD) have become an established therapy for heart failure. However, bleeding, thrombus formation and infection are still the most severe adverse events. Driven by advances in regenerative medicine, endothelial cell seeding is considered to be an important tool for optimizing haemocompatibility of artificial materials. Aiming towards improved haemocompatibility of LVAD systems, seeding properties of human cord blood derived endothelial cells (HCBEC) on sintered inflow cannula (SIC) were investigated. Methods and Materials: HCBEC were used for endothelialization of SIC and cultured for 7 days. Cell growth and seeding efficiency were quantified by fluorescence and scanning-electron-microscopy, as well as haemocompatibility of blank and endothelialized SIC after incubation with thrombocytes. Endothelial phenotype of HCBEC was analyzed by RT-PCR (e.g. CD31, vWF, VECad). Relative expression levels of endothelial specific activation (e.g. ICAM-1, VCAM-1) and thrombogenic state (e.g. thrombomodulin, tissue factor) markers were quantified using real-time RT-PCR. TNF -stimulation was used to examine their biologic reactivity. Results: HCBEC showed a stable endothelial phenotype. Relative expression levels of endothelial specific activation markers were unaffected by cell-to-SIC contact, but could be induced by TNF -stimulation. High expression levels of thrombomodulin and slight expression levels of tissue factor indicated a non-thrombogenic state. Microscopic analysis showed a nearly confluent endothelial monolayer on SIC and less adherent thrombocytes on endothelialized SIC compared to the blank ones. Conclusions: HCBEC seeded on SIC resulted in a non-activated and non-thrombogenic state while HCBEC maintained their biologic reactivity, as shown with TNF -stimulation. Endothelialization of SIC seems to improve haemocompatibility and may enhance long-term use of LVADsystems.