Martin Burdelski

Expression and localization of hepatobiliary transport proteins in progressive familial intrahepatic cholestasis

Mutations of the bile salt export pump (BSEP) or the multidrug resistance P‐glycoprotein 3 (MDR3) are linked to impaired bile salt homeostasis and lead to progressive familial intrahepatic cholestasis (PFIC)‐2 and ‐3, respectively. The regulation of bile salt transporters in PFIC is not known. Expression of hepatobiliary transporters in livers of ten patients with a PFIC phenotype was studied by quantitative reverse transcription polymerase chain reaction, Western blotting, and immunofluorescence microscopy. PFIC was diagnosed by clinical and laboratory findings. All patients could be assigned to PFIC‐2 or PFIC‐3 by the use of BSEP‐ and MDR3‐specific antibodies and by MDR3 gene‐sequencing. Whereas in all PFIC‐2 patients, BSEP immunoreactivity was absent from the canalicular membrane, in three PFIC‐3 livers, canalicular MDR3 immunoreactivity was detectable. Serum bile salts were elevated to 276 ± 233 and to 221 ± 109 μmol/L in PFIC‐2 and PFIC‐3, respectively. Organic anion transporting polypeptide OATP1B1, OATP1B3, and MRP2 mRNA and protein levels were reduced, whereas sodium taurocholate cotransporting polypeptide (NTCP) was only reduced at the protein level, suggesting a posttranscriptional NTCP regulation. Whereas MRP3 mRNA and protein were not significantly altered, MRP4 messenger RNA and protein were significantly increased in PFIC. In conclusion, PFIC‐2 may be reliably diagnosed by immunofluorescence, whereas the diagnosis of PFIC‐3 requires gene‐sequencing. Several mechanisms may contribute to elevated plasma bile salts in PFIC: reduced bile salt uptake via NTCP, OATP1B1, and OATP1B3, decreased BSEP‐dependent secretion into bile, and increased transport back into plasma by MRP4. Upregulation of MRP4, but not of MRP3, might represent an important escape mechanism for bile salt extrusion in PFIC. Supplementary material for this article can be found on the HEPATOLOGY website (http://www.interscience.wiley.com/jpages/0270‐9139/suppmat/index.html). (HEPATOLOGY 2005;41:1160–1172.)

Is There Still a Need for Living-related Liver Transplantation in Children?

ObjectiveTo assess and compare the value of split-liver transplantation (SLT) and living-related liver transplantation (LRT). Summary Background DataThe concept of SLT results from the development of reduced-size transplantation. A further development of SLT, the in situ split technique, is derived from LRT, which itself marks the optimized outcome in terms of postoperative graft function and survival. The combination of SLT and LRT has abolished deaths on the waiting list, thus raising the question whether living donor liver transplantation is still necessary. MethodsOutcomes and postoperative liver function of 43 primary LRT patients were compared with those of 49 primary SLT patients (14 ex situ, 35 in situ) with known graft weight performed between April 1996 and December 2000. Survival rates were analyzed using the Kaplan-Meier method. ResultsAfter a median follow-up of 35 months, actual patient survival rates were 82% in the SLT group and 88% in the LRT group. Actual graft survival rates were 76% and 81%, respectively. The incidence of primary nonfunction was 12% in the SLT group and 2.3% in the LRT group. Liver function parameters (prothrombin time, factor V, bilirubin clearance) and surgical complication rates did not differ significantly. In the SLT group, mean cold ischemic time was longer than in the LRT group. Serum values of alanine aminotransferase during the first postoperative week were significantly higher in the SLT group. In the LRT group, there were more grafts with signs of fatty degeneration than in the SLT group. ConclusionsThe short- and long-term outcomes after LRT and SLT did not differ significantly. To avoid the risk for the donor in LRT, SLT represents the first-line therapy in pediatric liver transplantation in countries where cadaveric organs are available. LRT provides a solution for urgent cases in which a cadaveric graft cannot be found in time or if the choice of the optimal time point for transplantation is vital.

De novo bile salt transporter antibodies as a possible cause of recurrent graft failure after liver transplantation: A novel mechanism of cholestasis

Progressive familial intrahepatic cholestasis type 2 (PFIC‐2) is caused by mutations of the bile salt export pump (BSEP [ABCB11]), an ATP‐binding cassette (ABC)‐transporter exclusively expressed at the canalicular membrane of hepatocytes. An absence of BSEP from the canalicular membrane causes cholestasis and leads to liver cirrhosis, which may necessitate liver transplantation in early childhood. We report on the first case of a child with PFIC‐2 suffering from repeated posttransplant recurrence of progressive intrahepatic cholestasis due to autoantibodies against BSEP. These antibodies occurred after transplantation and were detected in the patients serum and at the canalicular membrane of two consecutive liver transplants. The antibodies were reactive toward the first extracellular loop of BSEP, were of high affinity, and inhibited transport activity of BSEP, thus causing severe cholestasis. The patient had three homozygous, missense changes in the BSEP gene. Their combination resulted in the complete absence of BSEP, which explains the lack of tolerance, a prerequisite of autoantibody formation toward BSEP. The findings illustrate a novel disease mechanism due to a new class of functionally relevant autoantibodies resulting in cholestasis and subsequent liver failure. (HEPATOLOGY 2009;50:510–517.)

Liver Transplantation in Children With Progressive Familial Intrahepatic Cholestasis

Progressive familial intrahepatic cholestasis (PFIC) is caused by mutations of the bile salt export pump or the multidrug resistance P-glycoprotein, resulting in chronic hepatic failure. Partial external diversion of bile or ileal bypass is effective in some cases and, in others, liver transplantation (OLT) is necessary. Forty-two children were included in this study. Twenty-six children suffered from PFIC type 2 and 16 from PFIC type 3. Symptoms included pruritus, cholestasis, liver cirrhosis, and growth retardation. Seventeen patients received external biliary diversion. Ten had to undergo OLT in the following course. As of this report, three of the remaining patients were on the wait list for OLT. Twenty-three children received a liver graft primarily with excellent outcome. Our data show that OLT is the option of choice in symptomatic PFIC and whenever liver cirrhosis is present. We suggest a very restrictive recommendation of external biliary diversion. However, gene therapy may be a future option for children with PFIC.

Neonatal hemochromatosis: long-term experience with favorable outcome.

OBJECTIVE. Neonatal hemochromatosis is a severe, often fatal multiorgan disorder of iron metabolism. Liver transplantation can be curative; the benefit of antioxidant treatment is discussed controversially. We summarize our experience with neonatal hemochromatosis over the past 13 years. METHODS. A retrospective study was performed of 16 patients with acute liver failure attributable to neonatal hemochromatosis between 1992 and 2004. RESULTS. Median age at the onset of neonatal hemochromatosis was 2 days (range: 0–21 days). Median weight at the time of diagnosis was 2900 g (range: 1520–4200 g). All patients had elevated ferritin levels (median: 4179 μg/L), and transferrin saturation (median: 99%). Fourteen patients (87.5%) showed significant hepatocyte siderosis in biopsies; 4 children had additional iron deposition in extrahepatic tissue. Four patients were diagnosed by MRI. Seven infants received liver transplants, 5 of them in combination with a preceding antioxidant treatment. Four children (25%) received antioxidants without the necessity of liver transplantation and were in good clinical condition at the time of this evaluation. Five patients (31.3%) died, 3 of them without any treatment because of initial fulminant multiorgan failure. In September 2005, 68.7% of the patients were still alive after a median follow-up of 5 years. CONCLUSIONS. Neonatal hemochromatosis is a severe metabolic disease, but early antioxidant treatment and liver transplantation in addition to optimal medical care can improve the outcome dramatically. Children with moderate liver failure can survive without liver transplantation, but should be monitored closely for deterioration.

Low-dose immunosuppression reduces the incidence of post-transplant lymphoproliferative disease in pediatric liver graft recipients

Objectives In pediatric solid organ transplantation, the Epstein-Barr virus (EBV)-related lymphoproliferative disorders (PTLD) still play a major role in post-transplant morbidity and mortality. The aim of the study was to determine the incidence of PTLD in pediatric patients with liver transplant who receive low-dose immunosuppression protocols. Methods All pediatric patients (n = 269) received a dual immunosuppression therapy consisting of cyclosporine A (initial trough levels, 170–200 &mgr;g/L; trough levels for maintenance immunosuppression after 1 year, 80–100 &mgr;g/L) and prednisolone (starting dose, 60 mg/m2). Steroids were reduced to 30 mg/m2 after 1 week, followed by a weekly tapering to 5 mg/m2. Seventy-seven of 269 patients were switched to tacrolimus therapy. The authors evaluated the significance of EBV-DNA monitoring by quantitative polymerase chain reaction in identifying patients at risk for PTLD. Results Patient survival was 90.3%; graft survival was 85.9%. Eight patients lost their grafts because of chronic rejection. The incidence of PTLD was low (0.7%), although a significant EBV viral load was found in 42.4% of the patients. One third of the patients with a viral load of 3,000 genomes/105 cells or greater had clinical signs of EBV infection. Conclusions The authors conclude that low-dose immunosuppressive protocols significantly reduce the incidence of PTLD. In patients treated with that regimen, the monitoring of EBV viral load seems not to be helpful. It can be assumed that low-dose immunosuppression does not suppress EBV-specific cytotoxic CD8+ T cells, thus allowing the host to control EBV infection without the risk of PTLD. Our low-dose immunosuppression protocol did not increase the risk of chronic rejection.

Long‐term results of basiliximab induction immunosuppression in pediatric liver transplant recipients

Abstract:u2002 It has been shown that an induction therapy with the monoclonal anti‐interleukin‐2 receptor antibody basiliximab (SimulectTM) is capable to reduce the incidence of acute graft rejection in adult and pediatric liver transplantation (Ltx). However, data on long‐term results using basiliximab in children post‐Ltx are still pending. Therefore, the objective of our study was to report on the long‐term results of basiliximab induction therapy in pediatric liver transplant recipients. A total of 54 children received two single doses of basiliximab in addition to cyclosporine and prednisolone following Ltx. We analyzed the incidence of acute and chronic graft rejection that of post‐transplant lymphoproliferative disease (PTLD), and patient and graft survival. The follow‐up was 22–46u2003months. The historical control group (matched controls) consisted of 54 patients treated with a cyclosporine and prednisolone dual therapy. Patient survival was 53 of 54 in the treatment group and 51 of 54 in the controls. One patient was retransplanted in the treatment group vs. three patients in the control group. The incidence of acute graft rejection was 16.6% compared with 53.7% in the control group (pu2003<u20030.001), that of chronic rejection was comparable in both groups (one of 54 vs. one of 54). The incidence of steroid resistant rejection was four of 54 vs. six of 54 that of PTLD were one of 54 vs. zero of 54. There were no adverse effects observed, which could be related to the antibody treatment. We conclude that basiliximab provides safe and effective induction immunosuppression in pediatric liver graft recipients. Short‐ and even long‐term results are excellent.

Cognitive performance of children who have undergone liver transplantation.

Background. We investigated the cognitive status and quality of life (QoL) in the late postoperative phase of children who had undergone liver transplantation (LTx). Methods. The sample consisted of 29 children who had undergone LTx at our center. The children were at least 6 years of age and had received the transplant between 3 and 10 years (mean 6.4 years) previously. In 16 of the 29 children, a living-related transplantation had been performed. Cognitive function was assessed with the three subscales of the Kaufman Assessment Battery for Children (K-ABC): the sequential processing scale, simultaneous processing scale, and achievement scale. QoL was measured with a specific questionnaire for children. Results. The children scored below the population mean but within the normal range on all subscales of the K-ABC, except for the sequential processing scale, on which the children scored significantly below the norm and below their own performance on the simultaneous processing scale. Scores were below average for everyday and psychic functions and in the normal range for social and physical functions on the QoL questionnaire. Age at transplantation and achievement in the K-ABC were highly negatively correlated. A multiple regression analysis revealed that age and height at transplantation, and also to a lesser degree the type of transplantation, predict the level of cognitive functioning in the late postoperative phase. Conclusion. We conclude that the cognitive functions and QoL of children in the late postoperative phase who have undergone LTx are at the lower end of the norm in the long-term follow-up. Children who are younger and more physically developed at the time of transplantation will have a better mental-development prognosis.

Cognitive abilities, behaviour and quality of life in children after liver transplantation

Kaller T, Boeck A, Sander K, Richterich A, Burdelski M, Ganschow R, Schulz KH. Cognitive abilities, behaviour and quality of life in children after liver transplantation. u2028Pediatr Transplantation 2010: 14:496–503.

Long-term evaluation of cyclosporine and tacrolimus based immunosuppression in pediatric liver transplantation.

Abstract:u2002 Both calcineurin inhibitors (CNIs), cyclosporine and tacrolimus, are widely used in pediatric liver transplant recipients and currently data are limited with regards to long‐term results using the one drug or the other in comparable low doses. We conducted the present study to assess the advantages and disadvantages of both drugs in children at least five yr post‐liver transplantation. A total of 129 children were enrolled in the study. Thirty‐eight of the children were switched to tacrolimus monotherapy for different reasons [steroid resistant graft rejection (nu2003=u200315), chronic rejection (nu2003=u20035), severe acute rejection (nu2003=u20034), repetitive acute graft rejection (nu2003=u20035), dysfunction of the transplant (nu2003=u20033), insufficient CsA metabolism (nu2003=u20033), hypertrichosis (nu2003=u20032), and CsA toxicity (nu2003=u20031)], four patients had primary tacrolimus therapy, and 87 patients are receiving cyclosporine. Mean trough levels were 5.3u2003±u20032.3u2003ng/mL (tacrolimus) and 73.6u2003±u200344.5u2003μ/L (cyclosporine), respectively at least five yr post‐orthotopic liver transplantation (OLT). There was no significant difference in the calculated glomerular filtration rate between children on cyclosporine and tacrolimus (142.7u2003+u200339.5u2003mL/min/1.73u2003m2 vs. 151.1u2003±u200344.1u2003mL/min/1.73u2003m2). The incidence of arterial hypertension was 7.1% vs. 9.2%, that of hepatotoxicity was 0% vs. 2.3%. Cosmetic changes were found in more than one‐third of the patients on cyclosporine and in 4.8% of the patients receiving tacrolimus. Quality of life was excellent in both groups (self assessment). The impact of CNIs on chronic graft dysfunction cannot be assessed by our present study. We conclude from the results that cyclosporine and tacrolimus are both excellent drugs for maintenance immunosuppression in the long‐term course following pediatric liver transplantation. However, this retrospective analysis is limited by the bias between children on CsA as compared with patients receiving tacrolimus. A prospective randomized controlled trial is needed in order to assess which CNI is the best for children following OLT.