MRE-269

MRE-269 is an active metabolite of selexipag, and acts as a selective IP receptor agonist. In Vitro: MRE-269 induces endothelium-independent vasodilation of rat extralobar pulmonary artery (EPA). MRE-269 or other IP receptor agonists including epoprostenol, iloprost, treprostinil and beraprost increase cAMP levels in hPASMC^[1]. MRE-269 induces concentration-dependent vasodilation in LPA(+), LPA(-), and SPA(-)^[3]. In Vivo: The vasorelaxant effects of MRE-269 on rat small intralobar pulmonary artery (SIPA) and EPA are the same, while the other IP receptor agonists induce less vasodilation in SIPA than in EPA^[1]. MRE-269 produces substantial relaxation of rat small pulmonary artery, although its effects are only significant at high concentrations of above 10 μM (pEC₅₀, 4.98±0.22). By contrast, in rat small pulmonary veins, MRE-269 only produces minimal relaxation over the whole concentration range, with only significant relaxation occurring at the two highest doses of MRE-269 of 10 and 100 μM^[2].