Abstract 210: Biosynthesis of D-series Resolvin by Isolated Vascular Cells and Tissues

Abstract

Introduction: Resolvin-D1 (RvD1) and other specialized pro-resolving lipid mediators (SPM) are synthesized in-vivo from docosahexaenoic acid (DHA) through transcellular pathways involving leukocytes. We investigated if vascular tissues, in the absence of inflammatory cells, can contribute to the local production of SPM. Methods: Primary cultures of human saphenous vein endothelial (EC) and smooth muscle (SMC) cells were supplemented with DHA in cell culture media (10% serum) for 4h-24h. Freshly harvested rabbit aorta was incubated intact or following gentle EC denudation in medium with or without DHA for 48h. RvD1 levels were quantified by ELISA, and lipoxygenase (LO) expression by western blotting. Results: In the absence of DHA supplementation, EC and SMC produced undetectable levels of RvD1. DHA treatment produced a dose and time-dependent increase in RvD1 production by EC and SMC (10.1 ±1.0 pg, 7.4 ±0.2 pg respectively; 1000nM DHA; 24h; Fig A, B). 5-LO expression was demonstrated in both cell types, however DHA induced increased 5-LO expression in EC (Fig C) but not in SMC. DHA-treated intact rabbit aorta segments produced 0.24±0.05 pg RvD1/mg tissue versus 0.13±0.01 pg RvD1/mg tissue in media alone. Moreover, EC-denuded aortas produced significantly less RvD1 (Fig D). Conclusions: Human vascular cells and rabbit vascular tissue can biosynthesize RvD1 de novo from its precursor DHA, signifying a potentially important local source of SPM in the vasculature.