Background Liver transplantation is currently the only established treatment for end-stage liver disease, but it is limited by a severe shortage of viable donor livers. Donors after cardiac death (DCD) are an untapped source that could significantly increase the pool of available livers. Preservation of these DCD livers by conventional static cold storage (SCS) is associated with an unacceptable risk of primary non-function and delayed graft failure. Normothermic extracorporeal liver perfusion (NELP) has been suggested as an improvement over SCS. Methods Livers recovered from male Lewis rats were subjected to 1hr of warm ischemia and preserved with 5hrs of SCS or NELP, and transplanted into syngeneic recipients. As additional controls, non-ischemic livers preserved with 6hrs of SCS or NELP and unpreserved ischemic livers were transplanted. Results Following NELP, ischemically damaged livers could be orthotopically transplanted into syngeneic recipients with 92% survival (N=13) after 4 weeks, which was comparable to control animals which received healthy livers preserved by SCS (N=9) or NELP (N=11) for 6hrs. On the other hand, animals from ischemia/SCS control group all died within 12hrs post-operatively (N=6). Similarly, animals that received ischemic livers without preservation all died within 24hrs after transplantation (N=6). Conclusions These results suggest that NELP has the potential to reclaim warm ischemic livers that would not be transplantable otherwise. The rat model in this study is a useful platform to further optimize NELP as a method of recovery and preservation of DCD livers.

Integral to the development of embryonic stem cell therapeutic strategies for hepatic disorders is the identification and establishment of a controllable hepatic differentiation strategy. In order to address this issue we have established an alginate microencapsulation approach which provides a means to modulate the differentiation process through changes in key encapsulation parameters. We report that a wide array of hepatocyte specific markers is expressed by cells differentiated during a 23-day period within an alginate bead microenvironment. These include urea and albumin secretion, glycogen storage, and cytochrome P450 transcription factor activity. In addition, we demonstrate that cellular aggregation is integral to the control of differentiation within the bead environment and this process is mediated by the E-cadherin protein. The temporal expression of surface E-cadherin and hepatocyte functional expression occur concomitantly and both cellular aggregation and albumin synthesis are blocked in the presence of anti E-cadherin immunoglobulin. Furthermore, by establishing a compartmental model of differentiation, which incorporates this aggregation phenomenon, we can optimize key encapsulation parameters.

Background Utilizing livers from donors after cardiac death could significantly expand the donor pool. We have previously shown that normothermic (37°C) extracorporeal liver perfusion significantly improves transplantation outcomes of ischemic rat livers. Here we investigate whether recovery of ischemic livers is possible using sub-normothermic machine perfusion at 20°C and 30°C. Methods Livers from male Lewis rats were divided into five groups after 1 h of warm ischemia (WI): (1) WI only, (2) 5 h of static cold storage (SCS), or 5 h of MP at (3) 20°C, (4) 30°C, and (5) 37°C. Long-term graft performance was evaluated for 28 d post-transplantation. Acute graft performance was evaluated during a 2 h normothermic sanguineous reperfusion ex vivo. Fresh livers with 5 h of SCS were positive transplant controls while fresh livers were positive reperfusion controls. Results Following machine perfusion (MP) (Groups 3, 4, and 5), ischemically damaged livers could be orthotopically transplanted into syngeneic recipients with 100% survival (N ≥ 4) after 4 wk. On the other hand, animals from WI only, or WI + SCS groups all died within 24 h of transplantation. Fresh livers preserved using SCS had the highest alanine aminotransferase (ALT), aspartate aminotransferase (AST), and the lowest bile production during reperfusion, while at 28 d post-transplantation, livers preserved at 20°C and 30°C had the highest total bilirubin values. Conclusions MP at both 20°C and 30°C eliminated temperature control in perfusion systems and recovered ischemically damaged rat livers. Postoperatively, low transaminases suggest a beneficial effect of subnormothermic perfusion, while rising total bilirubin levels suggest inadequate prevention of ischemia- or hypothermia-induced biliary damage.