Although prostaglandin 12 is used to treat pulmonary hypertension (PH), continuous intravenous administration is necessary. We investigated whether human PGIS (hPGIS) gene transfer using adeno-associated virus (AAV) vector was effective in treating an animal model of PH. PH was induced by subjecting mice to 10% O-2. Type 1-AAV-hPGIS was injected into the left thigh muscle after 24 h. Significant PH was induced at 8 weeks, but AAV-hPGIS administration significantly inhibited the increase in RV systolic pressure. PH-induced BNP up-regulation in the RV was reduced to the control level. The severe medial thickening of pulmonary arteries in PH was significantly suppressed by AAV-hPGIS. The hPGIS gene was detected only on the injected side. No pathological changes were observed at the injected site. At 24 weeks, all PH mice were deceased.. but 47% of AAV-hPGIS-treated mice survived. This study demonstrated that AAV-hPGIS administration was effective in treating PH and prolonging survival. (C) 2007 Published by Elsevier Inc.