Resolvins are a family of potent lipid mediators derived from both eicosapentaenoic acid and docosahexaenoic acid.[1] In addition to being anti-inflammatory, resolvins promote the resolution of the inflammatory response back to a non-inflamed state.[2] Resolvin D1 is produced physiologically from the sequential oxygenation of DHA by 15- and 5-lipoxygenase.[1] 17(R)-RvD1 is an aspirin-triggered epimer of RvD1 that reduces human polymorphonuclear leukocyte (PMN) transendothelial migration, the earliest event in acute inflammation, with equipotency to RvD1 (EC50 = ~30 nM).[3] 17(R)-RvD1 exhibits a dose-dependent reduction in leukocyte infiltration in a mouse model of peritonitis with maximal inhibition of ~35% at a 100 ng dose.[3] In contrast to RvD1, the aspirin-triggered form resists rapid inactivation by eicosanoid oxidoreductases. Analytical and biological comparisons of synthetic 17(R)-RvD1 with endogenously derived 17(R)-RvD1 have confirmed its identity as matching the natural product.[4]
17(R)-Resolvin D3 (17(R)-RvD3) is an aspirin-triggered epimer of resolvin D3, produced from docosahexaenoic acid (DHA) through the action of COX-2 in the presence of aspirin, via a 17(R)-hydroperoxy DHA (17(R)-HDHA) intermediary. Identified in mouse inflammatory exudates, 17(R)-RvD3 notably inhibits the transmigration of isolated human polymorphonuclear cells (PMNs) and fosters the efferocytosis of apoptotic PMNs by macrophages. Furthermore, in a mouse model of zymosan-induced peritonitis, 17(R)-RvD3 administration (10 ng/animal) significantly curtails neutrophil infiltration into the peritoneal cavity and modulates cytokine levels by reducing IL-6 and increasing IL-10 in the inflammatory exudate. It engages GPR32, evidenced by activation in a β-arrestin reporter assay and augments phagocytosis more effectively in CHO cells overexpressing GPR32 compared to controls. Additionally, 17(R)-RvD3 enhances the clearance of etoposide-induced tumor cell debris by monocyte-derived macrophages in H460 human lung carcinoma.