ABSTRACTS 496 Heart, Lung and Circulation Abstracts of the ASCTS 2008 Annual Scientific Meeting 2010;19:483–510 Short Presentation 24 A New Method of Coating Vascular Prostheses with Endothelial Cells AK Ranjan 2,∗ , Ashutosh A Hardikar 1 , Anandwardhan A Hardikar 2,∗ 1 Royal Hobart Hospital, India 2 National Centre for Cell Sciences, India Introduction: Ability to coat prosthetic grafts with endothelial cells has been practised for a long time [1] and recent reviews [2] have favoured a two stage approach. The Achilles heel of these technologies has been finding a suitable matrix which enables the endothelial coat to adhere to the prosthesis. Here we would like to present our results with an innovative matrix using cultured human endothelial cells. Methods: Endothelial cells were obtained from human saphenous veins and internal thoracic arteries after col- lagenese treatment and were expanded million folds in vitro. After modifying surface properties of ePTFE tubings, we optimised conditions that would enhance adhesion of these endotheial cells. Adhesion assays were carried out using 96 well ELISA plates. We treated the hydrophobic plastic surfaces with ethanol / methanol and an acidified composition (Lim1) so as to change surface hydropho- bicity; and then coated them with Optimat and observed reduced hydrophobicity of the surface with increase in cell adhesion and growth. We were able to endothelise small diameter ePTFE tubing up to several cm and cells grown on such scaffolds were able to remain viable for several months in vitro and show immunopositivity to CD 31, CD 144, vWF, eNOS and UEA-1. Results: We found that the yield of endothelial cells from either artery or vein was similar and adhesion assays were best for ethanol treated Optimat surfaces. The ePTFE grafts sectioned weeks after initial coating showed intact coating of viable endothelial cells. Discussion: Although some authors have advised cau- tion [3], we are convinced that endothelial seeding of vascular grafts, valves [4] and possibly other scaffolds is the way to produce most biocompatible prostheses for human use. The need for culture facilities, cost and potential used only in elective cases remain the current obstacles. Our future plan is using this method to coat prostheses and move on to physiological testing. References [1] Bordenave, et al. Endothelium 1999;6(4):267–75. [2] Alobaid, et al. Clin Hemorheol microcirc 2005;33(3):209–26. [3] Rotmans, et al. Can J Cardiol 2006 Nov;22(13):1113–6. [4] Gulbins, et al. Ann Thorac Surg 2005;79:2119–26. doi:10.1016/j.hlc.2010.04.103 Short Presentation 25 A Novel Elastin-coated e-PTFE Vascular Conduit Michael Byrom 1,∗ , Steven Wise 2 , Paul Bannon 1 , Anthony Weiss 2 , Marcela Bilek 3 , Martin Ng 4 1 The Baird Institute, Sydney, Australia 2 School of Molecular and Microbial Biosciences, University of Sydney, Sydney, Australia 3 School of Physics, University of Sydney, Sydney, Australia 4 The Heart Research Institute, Sydney, Australia Introduction: ePTFE (expanded polytetrafluoroethy- lene) is the most commonly used synthetic vascular con- duit in peripheral vascular surgery where no autologous vessel is available or suitable. Despite repeated attempts at improvement in the 30 years since its development, ePTFE remains poorly biocompatible due to its inherent throm- bogenicity and failure to endothelialise when implanted. Elastin, a polymer constructed from tropoelastin, is an important extracellular matrix protein in elastic tissues such as the human vasculature. Last year we presented early studies demonstrating recombinant human tropoe- lastin to be a key candidate to address the poor biocom- patibility of current vascular synthetics. We now report the results of our work on elastin-coated ePTFE vascular conduits. Methods: A proprietary gas plasma technology was used to activate the luminal surface of ePTFE conduits to allow binding of tropoelastin. The plasma-treated surface was examined by scanning electron microscopy (SEM). Tropoelastin was radioactively labelled with iodine- 125 and strength of attachment to the ePTFE surface assessed. A novel stain technique was developed to visualise tropoelastin-coated surfaces. The ability of the tropoelastin coating to facilitate endothelialisation was assessed using human umbilical vein endothelial cells (HUVECs). Results: The luminal surface of ePTFE retained its characteristic structure under SEM with no appar- ent effect due to gas plasma treatment. 125 I-labelled tropoelastin demonstrated covalent binding of protein to the activated surface. Staining of tropoelastin allowed visualisation of coated surfaces (Fig. 1) as well as assess- ment by fluorescence microscopy. Coating tropoelastin onto activated ePTFE resulted in significantly enhanced HUVEC proliferation and resulted in endothelialisa- tion of the conduit surface. Six millimetre diameter elastin-coated ePTFE vascular conduits are undergo- ing in vivo assessment as carotid interposition grafts in sheep. Discussion: Early studies indicating the potential use of recombinant human tropoelastin as a new bio- material to improve the biocompatibility of currently available vascular synthetics have been confirmed using tropoelastin-coated ePTFE. Tropoelastin shows potential for the design of next generation cardiovascular devices,