[Beneficial effect of a stable PGI2 analogue (ONO-1301) on prostanoid release after reperfusion in canine left single lung allotransplantation model].

Recently much interests have focused on the imbalance between the release of thromboxane A2 (TXA2) and prostaglandin I2 (PGI2), which may contribute to the development of pulmonary vascular injury. TXB2 has potents of platelet aggregation and vasoconstriction, while PGI2 has against in its activities. We investigated the effect of new PGI2 analogue (ONO-1301), which is a novel prostacyclin mimetic with inhibitory activity against thromboxane synthetase, on the early graft function in canine left single lung allotransplantation model. 19 donor dogs were divided into three groups. Seven dogs were comprised control group and received heparin administration (400 Unit/kg) before pulmonary arterial flushing with 50 ml/kg of 4 degrees C low potassium dextran glucose (LPDG) solution. Each six dogs were comprised I2-10 and I2-50 groups respectively, with receiving a 10-minute infusion of ONO-1301 (10 micrograms/kg/min) before flushing. The pulmonary cold preservation was performed with LPDG solution at 4 degrees C for 18 hours. After left single lung transplantation, in control group, saline solution was administered to the recipient for 10 minutes encompassing the reperfusion process (starting from 5 minutes prior to reperfusion). In I2-10 group, the ONO-1301 (10 micrograms/kg/min) was administered in the same manner. In I2-50 group, the ONO-1301 was administered from the same timing as I2-10 group, but for 50 minutes. The recipient dogs were observed for 6 hours after ligation of the right pulmonary artery and bronchus. We measured the transplanted lung function, including arterial blood gas and pulmonary hemodynamics, and plasma 6-keto-PGF1 alpha, TXB2 and lipid peroxide levels of left atrial blood. Pulmonary histological investigation was performed after preservation and sacrifice the recipient dog. All recipient dogs were survived for observation period. I2 groups provided significantly better gas exchange and pulmonary hemodynamics than control group. The 6-keto-PGF alpha levels in control group peaked after an early rise in TXB2 levels, and reached maximum at one hour after contra-lateral ligations. These prostanoid release levels rose again at 6 hours. While in I2 groups, the levels of them were significantly lower compared with control group. Histological examination of the transplanted lung after assessment, revealed disruption of alveoli forced by pulmonary edema in control group. In contrast, there was minimal fluid extravasation without alveolar disruption in both I2-10 and I2-50 groups. There were no significant differences between I2-10 and I2-50 groups. Although it dose not protect the implanted lung completely from developing edema, the ONO-1301 administration (10 micrograms/kg/min) to the donor and the recipient resulted in prevention of TXA2 and PGI2 release and improvement of the respiratory function and pulmonary hemodynamics after reperfusion. We conclude that it seems beneficial to administer the ONO-1301 to the donor and the recipient in order to regulate the prostanoid release and maintain the early graft function.