Liver-based Metabolic Disorders Research Articles

Human hepatocyte transplantation: state of the art

Hepatocyte transplantation is making its transition from bench to bedside for liver-based metabolic disorders and acute liver failure. Over eighty patients have now been transplanted world wide and the safety of the procedure together with medium-term success has been established. A major limiting factor in the field is the availability of good quality cells as hepatocytes are derived from grafts that are deemed unsuitable for transplantation. Alternative sources of cell, including stem cells may provide a sustainable equivalent to primary hepatocytes. There is also a need to develop techniques that will improve the engraftment, survival and function of transplanted hepatocytes. Such developments may allow hepatocyte transplantation to become an accepted and practical alternative to liver transplantation in the near future.

Experience of Microbiological Screening of Human Hepatocytes for Clinical Transplantation

Hepatocyte transplantation is being used in patients with liver-based metabolic disorders and acute liver failure. Hepatocytes are isolated from unused donor liver tissue under GMP conditions. Cells must be free of microbiological contamination to be safe for human use. The experience of microbiological screening during 72 hepatocyte isolation procedures at one center is reported. Samples were taken at different stages of the process and tested using a blood culture bottle system and Gram stain. Bacterial contamination was detected in 37.5% of the UW organ preservative solutions used to transport the liver tissue to the Cell Isolation Unit. After tissue processing the contamination was reduced to 7% overall in the final hepatocyte product, irrespective of the presence of initial contamination of the transport solution. The most common organisms recovered were coagulase-negative staphylococci, a skin commensal. A total of 41 preparations of fresh or cryopreserved hepatocytes were used for cell transplantation in children with liver-based metabolic disorders without any evidence of sepsis due to infusion of hepatocytes. In conclusion, the incidence of bacterial contamination of the final product was low, confirming the suitability of the organs used, hepatocyte isolation procedure, and the environmental conditions of the clean room.

Pediatric Liver Transplantation for Metabolic Liver Disease: Experience at King’s College Hospital

The aims of this article were to report a single-center experience of pediatric liver transplantation for liver-based metabolic disorders and to compare the outcome of cirrhotic versus noncirrhotic metabolic liver disease. The medical records of 96 patients younger than 18 years undergoing transplantation for liver-based metabolic disorders from 1989 to 2005 were reviewed. Hundred twelve transplants were performed in 96 patients at a median age of 59.7 months (range, 0-208 months). The cumulative 1-, 5-, and 10-year graft and patient survival rates were 83%, 77%, and 62% and 91%, 86%, and 82%, respectively. Acute liver failure at first presentation (hazard ratio [HR] 3.0; 95% confidence interval [CI] 1.1-8.1), age less than 1 year at time of transplantation (HR 4.6; 95% CI 1.7-12.4) and hospitalization (HR 3.2; 95% CI 1.1-9.3) were significant predictors of worse patient survival. For noncirrhotic disorders, the long-term patient (100% vs. 100%, 90% vs. 100%, and 90% vs. 75%, P=0.87) and graft survivals (93% vs. 100%, 70% vs. 100%, and 70 vs. 75%, P=0.12) at 1, 5, and 7 years for auxiliary versus orthotopic transplantation were not significantly different. Long-term patient survival after transplantation for metabolic disorders is excellent for both cirrhotic and noncirrhotic metabolic disorders. For noncirrhotic metabolic disorders, auxiliary transplantation has similar patient and graft survival compared with orthotopic transplantation, but further research is recommended.

Liver after Hepatocyte Transplantation for Liver-Based Metabolic Disorders in Children

There are limited data regarding donor hepatocyte engraftment into recipient liver after human hepatocyte transplantation (HHTx). We reviewed the explant livers of seven children with metabolic disorders [ornithine-transcarbamylase deficiency (one), coagulation factor VII deficiency (three), Crigler-Najjar syndrome (one), progressive familial intrahepatic cholestasis type 2 (PFIC-2) deficiency (two)] who received allograft hepatocytes by intraportal infusion with improvement in phenotype, although all later underwent liver transplantation (LT). Immunohistochemistry for bile salt export protein (BSEP) in the PFIC-2 patients and genetic typing following laser capture microdissection (LCM) of liver cells in the others were used to identify donor hepatocytes in recipient explant livers. Explant livers usually showed a preserved lobular architecture. In one patient, hepatocytes were identified inside portal vein thrombi. No donor hepatocytes in liver cell plates were identified immunohistochemically or by genetic typing. HHTx was generally followed by partial recovery of metabolic function; the procedure was well tolerated; any increase in portal vein pressure was transient. Hepatocytes were identified in portal vein thrombi, even months after portal vein infusion. Further studies are needed to monitor donor hepatocytes in vivo, to quantify better the efficacy of the procedure and to find ways of improving engraftment and function.

Auxiliary Liver Transplantation for Propionic Acidemia: A 10‐Year Follow‐Up

Orthotopic liver transplantation (OLT) is an established treatment for patients with liver-based metabolic disorders that produce structural and functional impairment. Auxiliary liver transplantation (ALT) has been proposed as an alternative approach due to the potential advantage of preserving the native liver that could be used for future gene therapy and also serves as a back-up should the graft fail. The aim of our study was to determine if ALT has the long-term potential to correct the underlying abnormality in propionic acidemia (PA). A retrospective analysis was performed on graft function, metabolic parameters and effects on development in a child who underwent ALT for PA at our institute. The clinical and biochemical parameters are near normal with no diet restrictions and with good graft survival. A normal growth and an acceptable neurological and psychomotor development were achieved in the child. ALT is feasible and provides adequate liver mass to prevent metabolic decompensation in PA.

Hepatocyte transplantation for liver‐based metabolic disorders

Hepatocyte transplantation is being investigated as an alternative to orthotopic liver transplantation in patients with liver-based metabolic disorders. The progress made in this field to date is reviewed. Protocols have been developed using collagenase perfusion to isolate human hepatocytes from unused donor liver tissue. Hepatocytes with a high viability can often be obtained and can be cryopreserved for later use, though with loss of function on thawing. For clinical use, hepatocytes must be prepared in clean GMP conditions with cells meeting criteria of function and lack of microbial contamination before patient use. Hepatocytes are infused intraportally into the patient's liver, where a proportion of cells will engraft and replace the deficient metabolic function without the need for major surgery. Twenty patients have now received hepatocyte transplantation, including eight children at King's College Hospital. There was a range of aetiologies of liver disease: familial hypercholesterolaemia, Crigler-Najjar syndrome type 1, urea cycle defects, infantile Refsum disease, glycogen storage disease type Ia, inherited factor VII deficiency and progressive familial intrahepatic cholestasis type 2. Clinical improvement and partial correction of the metabolic abnormality was observed in most cases. Considerable progress has been made in developing the technique, but hepatocyte transplantation is limited by the available supply of liver tissue. Hepatocytes derived from stem cells could provide alternative sources of cells in the future.

Hepatocyte Transplantation for Inherited Factor VII Deficiency

Hepatocyte transplantation has been investigated in patients with liver-based metabolic disorders and acute liver failure. We report the first use of hepatocyte transplantation in two brothers with severe inherited coagulation factor VII deficiency. Patient 1 received a total of 1.09x10(9) cryopreserved hepatocytes, and patient received 2.18x10(9) fresh and cryopreserved hepatocytes through a Hickman line inserted in the inferior mesenteric vein. Infusion of isolated human hepatocytes improved the coagulation defect and markedly decreased the requirement for exogenous recombinant factor VII (rFVIIa) to approximately 20% of that before cell transplantation. In both patients, episodes of line sepsis were associated with an increase in rFVIIa requirement. Six months posthepatocyte transplantation, higher rFVIIa doses were required, suggesting loss of transplanted hepatocyte function. Because of increasing problems with venous access and long-term uncertainty of the efficacy of hepatocyte transplantation, orthotopic liver transplantation was performed successfully in both cases.

Hepatocyte transplantation

Hepatocyte transplantation

One liver, three recipients: segment IV from split-liver procedures as a source of hepatocytes for cell transplantation.

Hepatocyte transplantation is emerging as a possible treatment for patients with acute liver failure and liver-based metabolic disorders. With the limited availability of donor tissue, it is important to find new sources of liver tissue for isolation of high-quality hepatocytes. Segment IV with or without the caudate lobe was removed during three split-liver procedures. Hepatocytes were isolated from the tissues using a collagenase perfusion technique under strict sterile conditions. The mean number of hepatocytes that were isolated was 5.14 x 10(8) cells with a mean cell viability of 89%. Two of the hepatocyte preparations were used for cell transplantation in a 1-day-old boy with an antenatal diagnosis of a severe urea cycle defect caused by ornithine transcarbamylase deficiency. The six recipients of split-liver grafts demonstrated no complications related to the removal of segment IV. Segment IV with or without the caudate lobe obtained from split-liver procedures is potentially a good source of high-quality hepatocytes for cell transplantation.

Human hepatocyte isolation and relationship of cell viability to early graft function.

Hepatocyte transplantation is emerging as an additional modality of treatment for patients with acute liver failure or liver-based metabolic disorders. The procedure requires isolation of high-quality hepatocytes from unused donor livers. Hepatocytes were isolated from 20 donor livers (11 right lobes, 3 left lateral segments, 6 whole livers) using a collagenase perfusion technique. Cell viability (median 56%, range 13-95%) and yield (median 1.4 x 10(9) cells, range 2.0 x 10(6)-1.8 x 10(10) cells) varied according to the tissue available. Fatty livers rejected for transplantation gave lower cell viability (median 45%, range 25-59%). There was a significant correlation between age of donor (median 21 years, range 7-66 years) and viability of isolated hepatocytes in vitro (r = -0.683, p = 0.001). The 13 segments of livers were from reduced/split grafts used for clinical transplantation in 9 children and 4 adults. There was no significant correlation between in vitro cell viability and clinical parameters including intensive care stay, serum aspartate aminotransferase,and international normalized ratio (in the first 7 days), and allograft rejection or other early posttransplant complications, in patients transplanted with the corresponding tissue.

Pediatric liver transplantation.

Liver transplantation in children has become a treatment of choice for end-stage liver disease. Both graft and patient survival has significantly improved over the last two decades. The major factor contributing towards improved survival is availability of cyclosporin. Surgical innovations like living related donation has not only increased the donor pool, but has also helped patients in countries where cadaveric donation is not available. Auxiliary liver transplantation has made a significant change to the management of children with liver-based metabolic disorders and, in selected cases of acute liver failure, immunosuppression can be safely withdrawn once the native liver recovers. However, the complications associated with immunosuppression, such as nephrotoxicity, lymphoproliferative disease and viral infections, continue to be a matter of great concern. Most children with good graft function enjoy near normal quality of life.

Orthotopic liver transplantation in liver-based metabolic disorders.

The efficacy of orthotopic liver transplantation (OLT) in the management of more common liver-based metabolic disorders associated with severe liver damage, alpha-1-antitrypsin deficiency (PIZZ), Wilson disease and tyrosinaemia has been demonstrated and indications defined. An early mortality in excess of 15% and finite resources limit its use. Phenotypic heterogeneity make the precise indication in other disorders less certain. In disorders in which endstage liver disease is less frequent such as cystic fibrosis, haemochromatosis and galacosaemia it has been a very effective therapy. It has been used with encouraging results in disorders in which the liver is structurally normal such as Crigler-Najjar type I, primary hyperoxaluria type I and primary hypercholesterolaemia. In these it should be performed before there is permanent damage to brain, kidneys or heart. OLT in the short term prevents hyperammonaemic coma in urea cycle defects and may prevent extrahepatic disease in glycogen storage disease type IV. Its limitation in reversing all metabolic effects in these and other disorders is discussed. It is ineffective in protoporphyria or Niemann Pick disease type II (Sea Blue Histiocyte syndrome) in which the transplanted liver acquires the lesions of the initial disorder and extrahepatic features progress. Early referral provides optimum circumstances to assess the benefits of OLT as compared with those of other forms of management and to achieve transplantation at the ideal time. The place of OLT in management will require constant review as metabolic disorders are better defined, new forms of therapy evolve and as techniques of liver transplantation and modes of immunosuppression improve.