Reverse remodeling of pulmonary arteries by high-dose prostaglandin I2 therapy: A case report

Idiopathic pulmonary arterial hypertension (IPAH) is characterized by pulmonary vascular remodeling. We have reported that high-dose prostaglandin I2 (PGI2) therapy markedly improved hemodynamics in IPAH patients and that PGI2 induced apoptosis of pulmonary artery smooth muscle cells obtained from IPAH patients. PGI2 is thought to have reverse remodeling effects, although it has not been histologically confirmed. In a case series, we examined the reverse pulmonary vascular remodeling effects of PGI2 in lung tissues obtained from an IPAH patient treated with high-dose PGI2 and an IPAH patient not treated with PGI2. Apoptotic cells were detected in small pulmonary arteries of the IPAH patient treated with high-dose PGI2 but not in those from the IPAH patient not treated with PGI2. Media of peripheral pulmonary arteries were thick in the IPAH patient not treated with PGI2. On the other hand, media of peripheral pulmonary arteries were thin in the IPAH patient treated with high-dose PGI2. The single case report suggested that high-dose PGI2 therapy has the potential for reverse pulmonary vascular remodeling by induction of apoptosis and reduction of medial hypertrophy. Accumulation of cases is needed for the application to generalized effect of high-dose PGI2.