“…18 Interestingly, another PGI 2 analogue, treprostinil, also inhibits the proliferation of human and mouse primary lung fibroblasts through the activation of a peroxisome proliferator-activated receptor-/␦ when used in equivalent doses. 19 These observations suggest that high levels of PGI 2 may attenuate PA remodeling in vivo through antiproliferative effects. Consistent with previous studies, we demonstrated that high levels of endogenous PGI 2 successfully attenuated medial hypertrophy of the PA. 3,4,6 To discover new drug targets, the roles of peroxisome proliferator-activated receptors and high-level PGI 2 in PAH therapy should be determined, because peroxisome proliferator-activated receptors are associated with many inflammatory and proliferative disorders, including PAH.…”