🎗Translation study to document application of treprostinil for minimizing ischemia-reperfusion injury in donation after circulatory death livers using normothermic machine perfusion

Introduction: Liver transplantation (LT) remains the only treatment of choice for patients with end-stage liver disease. Livers obtained from donation after circulatory death (DCD) are subjected to significant ischemia-reperfusion injury (IRI) and require measures for organ preservation. Treprostinil is a synthetic prostacyclin analog with vasodilatory, anti-inflammatory, and  anti-platelet properties that can protect the vascular endothelia and minimize IRI in livers. The overall objective of our study was to evaluate the protective effect of treprostinil in minimizing IRI in DCD livers using normothermic machine perfusion (NMP).
Methods: Circulatory arrest was induced in male Sprague-Dawley rats, and the organs were subjected to 30 min of warm ischemic time (WIT) in situ, mimicking the process of DCD LT. Livers were procured and cold-preserved until mounted to ex vivo NMP. DCD livers underwent NMP with or without 20 ng/mL treprostinil in the perfusate for 4 h. Perfusate and bile samples were collected to assess hepatic and biliary viability parameters.
Results: Treprostinil effectively minimized IRI in DCD rat livers. Levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were significantly higher in the DCD-control group, whereas treprostinil supplementation during NMP reduced the levels by 50% (P < 0.001) and 30% (P = 0.036) compared with DCD-control, respectively. The portal vascular resistance was higher in the DCD-control group (0.45 ± 0.2 mm Hg/mL/min) and was significantly lower in the DCD-treprostinil group (0.2 ± 0.03 mm Hg/mL/min; P < 0.0001). Treprostinil increased eNOS expression by 5-fold (P = 0.013) and decreased mRNA expression of ICAM-1 by 73% (P = 0.002) and TNF-α by 70% (P = 0.012) compared to DCD-controls. Livers perfused with treprostinil produced 1.5-fold (P < 0.01) higher bile volume, compared to DCD-control and showed improved bile pH and lactate dehydrogenase (LDH) levels, which were comparable to those of naïve livers. Histological and ultrastructural analyses demonstrated improved hepatocyte integrity, preserved bile duct architecture, and reduced mitochondrial injury.

Conclusions: Treprostinil supplementation during NMP of DCD livers significantly reduced IRI and improved hepatobiliary function. These findings provide strong mechanistic and functional support for clinical translation. An ongoing pilot study with human DCD livers aims to translate these finding into clinical practice and enhance utilization of marginal grafts.