Yukihiro Saito, Kazufumi Nakamura, Satoshi Akagi, Toshihiro Sarashina, Kentaro Ejiri, Aya Miura, Aiko Ogawa, Hiromi Matsubara, Hiroshi Ito

The release of endogenous prostacyclin (PGI2) is depressed in patients with pulmonary arterial hypertension (PAH). PGI2 replacement therapy by epoprostenol infusion is one of the best treatments available for PAH. Here, we provide an overview of the current clinical data for epoprostenol. Epoprostenol treatment improves symptoms, exercise capacity, and hemodynamics, and is the only treatment that has been shown to reduce mortality in patients with idiopathic PAH (IPAH) in randomized clinical trials. We have reported that high-dose epoprostenol therapy (>40 ng/kg/min) also results in marked hemodynamic improvement in some patients with IPAH. High-dose epoprostenol has a pro-apoptotic effect on PAH-PASMCs via the IP receptor and upregulation of Fas ligand (FasL) in vitro. However, long-term intravenous administration of epoprostenol is sometimes associated with catheter-related infections and leads to considerable inconvenience for the patient. In the future, the development of new routes of administration or the development of powerful PGI2 analogs, IP-receptor agonists, and gene and cell-based therapy enhancing PGI2 production with new routes of administration is required.