Using old liver grafts for liver transplantation: Where are the limits?

Liver-Regenerative Transplantation: Regrow and Reset

Liver transplantation, either a partial liver from a living or deceased donor or a whole liver from a deceased donor, is the only curative therapy for severe end-stage liver disease. Only one-third of those on the liver transplant waiting list will be transplanted, and the demand for livers is projected to increase 23% in the next 20 years. Consequently, organ availability is an absolute constraint on the number of liver transplants that can be performed. Regenerative therapies aim to enhance liver tissue repair and regeneration by any means available (cell repopulation, tissue engineering, biomaterials, proteins, small molecules, and genes). Recent experimental work suggests that liver repopulation and engineered liver tissue are best suited to the task if an unlimited availability of functional induced pluripotent stem (iPS)-derived liver cells can be achieved. The derivation of iPS cells by reprogramming cell fate has opened up new lines of investigation, for instance, the generation of iPS-derived xenogeneic organs or the possibility of simply inducing the liver to reprogram its own hepatocyte function after injury. We reviewed current knowledge about liver repopulation, generation of engineered livers and reprogramming of liver function. We also discussed the numerous barriers that have to be overcome for clinical implementation.

Overextended Criteria Donors: Experience of an Italian Transplantation Center

The increasing gap between the number of patients who could benefit from liver transplantation and the number of available donors has fueled efforts to maximize the donor pool using marginal grafts that usually were discarded for transplantation. This study included data of all patients who received decreased donor liver grafts between January 2004 and January 2013 (n = 218) with the use of a prospectively collected database. Patients with acute liver failure, retransplantation, pediatric transplantation, and split liver transplantation were excluded. Donors were classified as standard donor (SD), extended criteria donor (ECD), and overextended criteria donor (OECD). The primary endpoints of the study were early allograft primary dysfunction (PDF), primary nonfunction (PNF), and patient survival (PS), whereas incidence of major postoperative complications was the secondary endpoint. In our series we demonstrated that OECD have similar outcome in terms of survival and incidence of complication after liver transplantation as ideal grafts.

The impact of donor liver graft quality on postoperative outcome in liver transplant recipients. A single centre experience

INTRODUCTION

The Donor Risk Index (DRI) has become a universal score for organ allocation in liver transplantation (LT) worldwide. The aim of this study was to evaluate the impact of liver graft quality measured by DRI, CIT, WIT and donor age on intraoperative hemodynamics (reperfusion syndrome) and early postoperative outcome, defined as initial graft poor function (within 3 days of LT), of deceased donor liver transplant (DDLT) recipients. Secondary end-points were the assessment of the impact of graft quality on the intraoperative and postoperative day 1 hemostasis (evaluated using ROTEM assay).

METHODS

We retrospectively analyzed 135 patients who underwent deceased-donor LT between January 2013 and December 2014. Patient demographic data (age, sex, cause of End-Stage Liver Disease), preoperative paraclinical data (total bilirubin, creatinine, serum sodium), severity of liver disease scores (Model for End-Stage Liver Disease - MELD and MELD-sodium), intraoperative blood loss and blood products transfusion, incidence of post reperfusion syndrome, postoperative biochemical data (including total bilirubin, hepatic transaminases, lactate levels) and outcome (initial graft poor function diagnosis) were noted. Donor characteristics including DRI, CIT, WIT and donor age were noted. Coagulation was assessed by rotational thromboelastometry (ROTEM) after reperfusion of the graft and on postoperative day 1 in order to determine the effects of liver graft quality on hemostasis.

RESULTS

Donor age has significantly correlated with decreased derived ROTEM parameters time to the maximum velocity of clot formation - MaxVt (p = 0.000), area under the curve (AUC) (p = 0.008) and maximum clot elasticity (MCE) (p = 0.018) although no difference in transfusion requirements has been observed. A longer CIT was associated with an increase in AST and ALT observed during the early postoperative period: day 1 ALT (p = 0.032) and AST (p = 0.008), day 2 ALT (p = 0.001) and AST (p = 0.001) and day 3 AST (p = 0.010) and ALT (p = 0.001). Higher DRI correlated with higher bilirubin levels measured on postoperative day 1 (p = 0.027) and 2 (p = 0.001). Patients who developed initial graft poor function received liver grafts from older donors (p = 0.05) with a higher DRI (p = 0.002).

CONCLUSION

Our results suggest a significant impact of donor age and DRI on perioperative coagulation kinetics that may be a result of initial graft poor function. Although CIT and DRI correlated with a more severe cholestasis and hepatocitolysis during the early postoperative period these seems to be short-lived.

Strategies to optimize the use of marginal donors in liver transplantation

Liver transplantation is the treatment of choice for end stage liver disease, but availability of liver grafts is still the main limitation to its wider use. Extended criteria donors (ECD) are considered not ideal for several reasons but their use has dramatically grown in the last decades in order to augment the donor liver pool. Due to improvement in surgical and medical strategies, results using grafts from these donors have become acceptable in terms of survival and complications; nevertheless a big debate still exists regarding their selection, discharge criteria and allocation policies. Many studies analyzed the use of these grafts from many points of view producing different or contradictory results so that accepted guidelines do not exist and the use of these grafts is still related to non-standardized policies changing from center to center. The aim of this review is to analyze every step of the donation-transplantation process emphasizing all those strategies, both clinical and experimental, that can optimize results using ECD.

Future Economics of Liver Transplantation: A 20-Year Cost Modeling Forecast and the Prospect of Bioengineering Autologous Liver Grafts

During the past 20 years liver transplantation has become the definitive treatment for most severe types of liver failure and hepatocellular carcinoma, in both children and adults. In the U.S., roughly 16,000 individuals are on the liver transplant waiting list. Only 38% of them will receive a transplant due to the organ shortage. This paper explores another option: bioengineering an autologous liver graft. We developed a 20-year model projecting future demand for liver transplants, along with costs based on current technology. We compared these cost projections against projected costs to bioengineer autologous liver grafts. The model was divided into: 1) the epidemiology model forecasting the number of wait-listed patients, operated patients and postoperative patients; and 2) the treatment model forecasting costs (pre-transplant-related costs; transplant (admission)-related costs; and 10-year post-transplant-related costs) during the simulation period. The patient population was categorized using the Model for End-Stage Liver Disease score. The number of patients on the waiting list was projected to increase 23% over 20 years while the weighted average treatment costs in the pre-liver transplantation phase were forecast to increase 83% in Year 20. Projected demand for livers will increase 10% in 10 years and 23% in 20 years. Total costs of liver transplantation are forecast to increase 33% in 10 years and 81% in 20 years. By comparison, the projected cost to bioengineer autologous liver grafts is $9.7M based on current catalog prices for iPS-derived liver cells. The model projects a persistent increase in need and cost of donor livers over the next 20 years that’s constrained by a limited supply of donor livers. The number of patients who die while on the waiting list will reflect this ever-growing disparity. Currently, bioengineering autologous liver grafts is cost prohibitive. However, costs will decline rapidly with the introduction of new manufacturing strategies and economies of scale.

Elderly donor liver grafts are not associated with a higher incidence of biliary complications after liver transplantation: results of a national multicenter study

BACKGROUND

Liver transplantation with livers grafts from elderly donors has been associated with a higher risk of biliary complications. The aim of this study was to examine whether our national protocol could contribute to a lower incidence of biliary complications.

METHODS

All adult recipients in the Netherlands transplanted with a liver from an elderly donor (≥ 65 yrs; n = 68) in the period January 2000-July 2011 were matched with recipients of a liver from a donor <65 yr (n = 136). Outcome parameters were 90-d, one-yr, and three-yr patient/graft survival rates, biliary complications (non-anastomotic stricture, anastomotic stricture, biliary leakage, and post-transplant cholangitis), and postoperative hepatic ischemic injury serum markers (AST/ALT).

RESULTS

The median cold ischemia time (CIT) was 7:25 (h:min) in the group recipients of an elderly donor liver graft. Ninety-day, one-yr, and three-yr patient/graft survival rates were similar between the group with an elderly donor liver and their younger controls. Moreover, no differences were found in the incidence of biliary complications and postoperative levels of AST/ALT between the two groups.

CONCLUSION

Transplantation of livers from elderly donors (≥ 65 yr) is not associated with a higher incidence of biliary complications, in a national policy wherein the CIT is kept short.

Loss of α1,6-fucosyltransferase suppressed liver regeneration: implication of core fucose in the regulation of growth factor receptor-mediated cellular signaling

Core fucosylation is an important post-translational modification, which is catalyzed by α1,6-fucosyltransferase (Fut8). Increased expression of Fut8 has been shown in diverse carcinomas including hepatocarcinoma. In this study, we investigated the role of Fut8 expression in liver regeneration by using the 70% partial hepatectomy (PH) model, and found that Fut8 is also critical for the regeneration of liver. Interestingly, we show that the Fut8 activities were significantly increased in the beginning of PH (~4d), but returned to the basal level in the late stage of PH. Lacking Fut8 led to delayed liver recovery in mice. This retardation mainly resulted from suppressed hepatocyte proliferation, as supported not only by a decreased phosphorylation level of epidermal growth factor (EGF) receptor and hepatocyte growth factor (HGF) receptor in the liver of Fut8^−/− mice in vivo, but by the reduced response to exogenous EGF and HGF of the primary hepatocytes isolated from the Fut8^−/− mice. Furthermore, an administration of L-fucose, which can increase GDP-fucose synthesis through a salvage pathway, significantly rescued the delayed liver regeneration of Fut8^+/− mice. Overall, our study provides the first direct evidence for the involvement of Fut8 in liver regeneration.