(651e) Resuscitation of Ischemic Donor Livers with Ex Vivo Machine Perfusion: A Dynamic Metabolic Analysis of Treatment in Rats

The success of orthotopic liver transplantation as the only effective treatment for end stage liver failure has created a demand for viable organs that far exceeds the current supply. This further necessitates that the source of healthy hepatocytes in the fields of cell therapeutics, pharmacotoxicology, tissue engineering, and bioartificial assist devices must derive from suboptimal sources; untreated discarded donor organs, segments from reduced cadaveric grafts or, in some applications, xenografts. In this study we investigated the ability of ex vivo perfusion to reverse ischemic organ damage, thereby gaining access to a significant source of transplantable organs or hepatocytes from otherwise discarded organs. Metabolic flux analysis (MFA) was used to establish optimal perfusion designs: 1) A system that operates at 37°C and restores livers exposed to 1hr of warm ischemia (WI, 34°C) to transplantable state (>1mo survival). Control groups comprising ischemic livers stored in UW at 4°C resulted in 100% transplant mortality. 2) A highly simplified system that operates at room temperature to increase hepatocyte yield 17-fold from WI livers, in addition to increasing fresh liver hepatocyte yields by 32%. All perfusion-recovered hepatocytes functioned equally well or better than fresh controls in suspension and plate cultures. A direct correlation between cell yield and tissue ATP content is established enabling objective measures of organ viability and recovery during perfusion. Additionally, a strong correlation between low perfusion flow rate and high cell yield is observed thereby setting the boundary conditions for fine-tuned optimization of organ recovery. These results scaled to human livers will impact the donor organ shortage dramatically.