Barbara Wildhaber

Impact of age at Kasai operation on its results in late childhood and adolescence: a rational basis for biliary atresia screening

BACKGROUND. Increased age at surgery has a negative impact on results of the Kasai operation for biliary atresia in infancy and early childhood. It remained unclear if an age threshold exists and if this effect persists with extended follow-up. In this study we examined the relationship between increased age at surgery and its results in adolescence. METHODS. All patients with biliary atresia who were living in France and born between 1986 and 2002 were included. Median follow-up in survivors was 7 years. RESULTS. Included in the study were 743 patients with biliary atresia, 695 of whom underwent a Kasai operation; 2-, 5-, 10-, and 15-year survival rates with native liver were 57.1%, 37.9%, 32.4%, and 28.5%, respectively. Median age at Kasai operation was 60 days and was stable over the study period. Whatever the follow-up (2, 5, 10, or 15 years), survival rates with native liver decreased when age at surgery increased (≤30, 31–45, 46–60, 61–75, and 76–90 days). Accordingly, we estimated that if every patient with biliary atresia underwent the Kasai operation before 46 days of age, 5.7% of all liver transplantations performed annually in France in patients younger than 16 years could be spared. CONCLUSIONS. Increased age at surgery had a progressive and sustained deleterious effect on the results of the Kasai operation until adolescence. These findings indicate a rational basis for biliary atresia screening to reduce the need for liver transplantations in infancy and childhood.

Biliary atresia: Swiss national study, 1994-2004

Objectives: To determine the epidemiology of biliary atresia (BA) in Switzerland, the outcome of the children from diagnosis, and the prognostic factors. Patients and Methods: The records of all patients with BA born in Switzerland between January 1994 and December 2004 were analyzed. Survival rates were calculated with the Kaplan-Meier method, and prognostic factors evaluated with the log rank test. Median follow up was 58 months (range, 5–124). Results: BA was diagnosed in 48 children. Incidence was 1 in 17,800 live births (95% confidence interval 1/13,900–1/24,800), without significant regional, annual, or seasonal variation. Forty-three children underwent a Kasai portoenterostomy (PE) in 5 different Swiss pediatric surgery units. Median age at Kasai PE was 68 days (range, 30–126). Four-year survival with native liver after Kasai PE was 37.4%. Liver transplantation (LT) was needed in 31 in 48 children with BA, including 5 patients without previous Kasai PE. Four patients (8%, all born before 2001) died while waiting for LT, and 29 LT were performed in 27 patients (28 in Geneva and 1 in Paris). All of the transplanted patients are alive. Four-year overall BA patient survival was 91.7%. Four-year survival with native liver was 75% in patients who underwent Kasai PE before 46 days, 33% in patients operated on between 46 and 75 days, and 11% in patients operated on after 75 days (P = 0.02). Conclusions: Overall survival of patients with BA in Switzerland compares favorably with current international standards, whereas results of the Kasai operation could be improved to reduce the need for LTs in infancy and early childhood.

Loss of transcriptional control over endogenous retroelements during reprogramming to pluripotency

Endogenous retroelements (EREs) account for about half of the mouse or human genome, and their potential as insertional mutagens and transcriptional perturbators is suppressed by early embryonic epigenetic silencing. Here, we asked how ERE control is maintained during the generation of induced pluripotent stem cells (iPSCs), as this procedure involves profound epigenetic remodeling. We found that all EREs tested were markedly up-regulated during the reprogramming of either mouse embryonic fibroblasts, human CD34(+) cells, or human primary hepatocytes. At the iPSC stage, EREs of some classes were repressed, whereas others remained highly expressed, yielding a pattern somewhat reminiscent of that recorded in embryonic stem cells. However, variability persisted between individual iPSC clones in the control of specific ERE integrants. Both during reprogramming and in iPS cells, the up-regulation of specific EREs significantly impacted on the transcription of nearby cellular genes. While transcription triggered by specific ERE integrants at highly precise developmental stages may be an essential step toward obtaining pluripotent cells, the broad and unspecific unleashing of the repetitive genome observed here may contribute to the inefficiency of the reprogramming process and to the phenotypic heterogeneity of iPSCs.

Varicella‐Zoster Immunization in Pediatric Liver Transplant Recipients: Safe and Immunogenic

Varicella can have a severe course in immunosuppressed patients. Although prevention is fundamental, live‐attenuated varicella‐zoster (VZV) vaccine is not currently recommended in transplant recipients. Our aims were to (1) evaluate VZV immunity in pediatric liver transplant (LT) recipients; (2) immunize (two doses) seronegative patients post‐LT; (3) monitor vaccine safety, (4) assess B and T cell vaccine responses. All patients followed at the Swiss National Pediatric LT Center were approached and 77/79 (97.5%) were enrolled (median age 7.8 years). Vaccine safety was monitored by standardized diary cards and phone calls. VZV‐specific serology and CD4+ T cells were assessed before and after immunization. Thirty‐nine patients (51.1%) were seronegative including 14 children immunized pre‐LT. Thirty‐six of 39 seronegative patients were immunized post‐LT (median 3.0 years post LT). Local (54.8%) and systemic (64.5%) reactions were mild and transient. The frequency of VZV‐specific CD4+ T cells and antibody titers increased significantly (respectively from 0.085% to 0.16%, p = 0.04 and 21.0 to 1134.5 IU/L, p < 0.001). All children reached seroprotective titers and 31/32 (97%) patients assessed remained seroprotected at follow‐up (median 1.7 years). No breakthrough disease was reported during follow‐up (median 4.1 years). Thereby, VZV vaccine appears to be safe, immunogenic and provide protection against disease in pediatric LT patients.

Biliary Atresia: 50 Years after the First Kasai

Biliary atresia is a rare neonatal disease of unknown etiology, where obstruction of the biliary tree causes severe cholestasis, leading to biliary cirrhosis and death in the first years of life, if the condition is left untreated. Biliary atresia is the most frequent surgical cause of cholestatic jaundice in neonates and should be evoked whenever this clinical sign is associated with pale stools and hepatomegaly. The treatment of biliary atresia is surgical and currently recommended as a sequence of, eventually, two interventions. During the first months of life a hepatoportoenterostomy (a “Kasai,” modifications of which are discussed in this paper) should be performed, in order to restore the biliary flow to the intestine and lessen further damage to the liver. If this fails and/or the disease progresses towards biliary cirrhosis and life-threatening complications, then liver transplantation is indicated, for which biliary atresia represents the most frequent pediatric indication. Of importance, the earlier the Kasai is performed, the later a liver transplantation is usually needed. This warrants a great degree of awareness of biliary atresia, and the implementation of systematic screening for this life-threatening pathology.

Ex vivo lentivirus transduction and immediate transplantation of uncultured hepatocytes for treating hyperbilirubinemic Gunn rat.

Background. Ex vivo liver gene therapy provides an attractive alternative to orthotopic liver transplantation for the treatment of liver diseases. We previously reported a protocol in which human primary hepatocytes are highly transduced in Suspension with Lentiviral vectors and Immediately Transplanted (SLIT). Here, we evaluated the SLIT approach in Gunn rats, the animal model for Crigler-Najjar syndrome type 1, a defect in bilirubin UDP-glucuronosyltransferase (BUGT). Methods. We constructed lentiviral vectors coding for BUGT under control of an ubiquitous promoter. Control vectors contained Green Fluorescent Protein (GFP) under control of the same promoter. Hepatocytes were isolated from jaundiced Gunn rats and transduced in suspension for four hr. After washing, 2×107 hepatocytes were immediately transplanted into syngeneic rats. Bilirubinemia and bile pigments were regularly assessed after cell transplantation. The percentage and presence of transduced hepatocytes was analyzed by immunohistochemistry in GFP-transplanted animals. Results. In rats receiving BUGT-transduced hepatocytes, bilirubinemia decreased by about 30%. The level of correction remained stable for up to 240 days. Bilirubin glucuronides were present in the bile of treated animals, indicating the metabolic activity of engrafted hepatocytes. In contrast, bilirubinemia in GFP-transplanted rats did not decline but rather increased. GFP-positive hepatocytes amounted to 0.5–1% of the liver, which is in agreement with the number of transplanted and genetically-modified hepatocytes (6×106). Conclusions. This work reports the first demonstration of long-term metabolic benefit after rapid transplantation of ex vivo lentivirally tranduced hepatocytes. Therefore, this study demonstrates the therapeutic proof-of-principle and potential of the SLIT approach for treating inherited metabolic liver diseases.

European biliary atresia registries: summary of a symposium.

Biliary atresia (BA) is a rare but potentially devastating disease. The European Biliary Atresia Registry (EBAR) was set up to improve data collection and to develop a pan-national and interdisciplinary strategy to improve clinical outcomes. From 2001 to 2005, 100 centers from 22 countries registered with EBAR via its website (www.biliary-atresia.com). In June 2006, the first meeting was held to evaluate results and launch further initiatives. During a 5-year period, 60 centers from 19 European countries and Israel sent completed registration forms for a total of 514 BA patients. Assuming the estimated incidence of BA in Europe is 1:18,000 live births, 35% of the expected 1488 patients from all EBAR participating countries were captured, suggesting that reporting arrangements need improvement. At the meeting, the cumulative evaluation of 928 BA patients including patients from other registries with variable follow-up revealed an overall survival of 78% (range from 41% to 92%), of whom 342 patients (37%) have had liver transplants. Survival with native liver ranged from 14% to 75%. There was a marked variance in reported management and outcome by country (e.g., referral patterns, timing of surgery, centralization of surgery). In conclusion, EBAR represents the first attempt at an overall evaluation of the outcome of BA from a pan-European perspective. The natural history and outcome of biliary atresia is of considerable relevance to a European population. It is essential that there is further support for a pan-European registry with coordination of clinical standards, further participation of parent support groups, and implementation of online data entry and multidisciplinary clinical and basic research projects.

Adult hepatoblastoma: Learning from children

Hepatoblastoma is the most common malignant liver tumour in infants and young children. Its occurrence in the adult population is debated and has been questioned. The aim of this paper is to review the histological and clinical features of adult hepatoblastoma as described in the adult literature, and to compare the findings with those of paediatric hepatoblastoma. The developmental and molecular aspects of hepatoblastoma are reviewed and their potential contribution to diagnosis of adult hepatoblastoma discussed. Case reports of adult hepatoblastoma identified by a PubMed search of the English, French, German, Italian, and Spanish literature through March 2011 were reviewed. Forty-five cases of hepatoblastoma were collected. Age at presentation was variable. Survival was uniformly poor, except for the rare patients who presented with the relatively differentiated, foetal type. The common denominator between adult and paediatric cases is the occurrence of embryonal or immature aspect of the tumours. Whether the adult cases of hepatoblastoma represent blastemal tumours, stem cell tumours, or unusual differentiation patterns in otherwise more frequent adult liver tumours remains to be established. Adult tumours labelled as hepatoblastoma are characterised by malignant appearing mesenchymal components. Surgical management is the cornerstone of therapy in children and also appears to confer an improved prognosis in adults. Whether adult hepatoblastoma exists, remains controversial. Indeed, several features described in adult cases are markedly different from hepatoblastoma as it is understood in children, and other differential diagnoses should also be entertained. Nonetheless, hepatoblastoma should be considered in adults presenting with primary liver tumours in the absence of pre-existing liver disease. Adult and paediatric patients with immature hepatoblastoma appear to have worse outcomes, and adults presenting with presumed hepatoblastoma have an overall poorer prognosis than children with hepatoblastoma. In all patients, surgery should be the treatment of choice, neoadjuvant chemotherapy is advisable.

Adrenocortical oncocytoma in a child

Adrenocortical oncocytoma is a rare epithelial tumor only described in adults. We report the case of a 12‐year‐old female who presented a left adrenal mass with abdominal pain, fatigue, acne vulgaris, and elevation of the androstenedione and total testosterone. She had an adrenalectomy. A diagnosis of adrenocortical oncocytoma was made after detailed histological, immunohistochemical, and ultrastructural studies. Pediatr Blood Cancer 2008;50:718–721.

A step toward liver gene therapy: efficient correction of the genetic defect of hepatocytes isolated from a patient with Crigler-Najjar syndrome type 1 with lentiviral vectors

Background. Ex vivo liver gene therapy may be a future alternative to orthotopic liver transplantation for the treatment of some liver diseases. We previously described the transduction in suspension with lentiviral vectors and immediate hepatocyte transplantation (SLIT) protocol and its high transduction rate with normal human hepatocytes. We also reported SLIT efficiency in the animal model of Crigler-Najjar type 1 syndrome (CN-1), the Gunn rat. Here, we evaluated SLIT efficiency with diseased human hepatocytes. Methods. Hepatocytes of the liver from a 4-year-old patient presenting CN-1 were isolated. They were transduced with liver-specific lentiviral vectors expressing uridine-diphosphate-glucuronosyltransferase (hUGT1A1) or green fluorescent protein, and then analyzed in vitro for transduction efficiency and hUGT1A1 expression, or transplanted in nonobese diabetic/severe combined immunodeficiency (SCID) mice to evaluate long-term survival of transplanted cells. Results. More than 90% of CN-1 hepatocytes were transduced. Hepatocytes produced hUGT1A1 protein after lentiviral transduction. After having been subjected to the SLIT, lentivirally transduced CN-1 hepatocytes engrafted long term (up to 26 weeks posttransplantation) in recipient livers and expressed green fluorescent protein or hUGT1A1 vector. Conclusion. The SLIT protocol allowed for a high transduction of CN-1 hepatocytes and restoration of the expression of the deficient protein. Furthermore, long-term survival of lentivirally transduced CN-1 hepatocytes in the liver of immunodeficient mice was demonstrated. This study is therefore an important step toward human application of lentiviral gene therapy.