Molecular investigations to improve diagnostic accuracy in patients with ARC syndrome

Arthrogryposis, Renal dysfunction and Cholestasis (ARC) syndrome is a multi-system autosomal recessive disorder caused by germline mutations in VPS33B. The detection of germline VPS33B mutations removes the need for diagnostic organ biopsies (these carry a>50% risk of life-threatening haemorrhage due to platelet dysfunction); however, VPS33B mutations are not detectable in approximately 25% of patients. In order further to define the molecular basis of ARC we performed mutation analysis and mRNA and protein studies in patients with a clinical diagnosis of ARC. Here we report novel mutations in VPS33B in patients from Eastern Europe and South East Asia. One of the mutations was present in 7 unrelated Korean patients. Reduced expression of VPS33B and cellular phenotype was detected in fibroblasts from patients clinically diagnosed with ARC with and without known VPS33B mutations. One mutation-negative patient was found to have normal mRNA and protein levels. This patient's clinical condition improved and he is alive at the age of 2.5 years. Thus we show that all patients with a classical clinical course of ARC had decreased expression of VPS33B whereas normal VPS33B expression was associated with good prognosis despite initial diagnosis of ARC.

Management strategies for hepatitis C virus infection in children

Chronic hepatitis C virus (HCV) infection is a major cause of morbidity and mortality worldwide. Progression to cirrhosis and hepatocellular carcinoma occurs in 20% of infected adults. The natural history following childhood infection is less well defined, although cirrhosis in children is described. Since blood product screening for HCV infection was introduced in 1990, most children who acquire HCV do so by vertical transmission from an infected mother. Transmission to offspring occurs in approximately 5%. Most children with HCV infection are asymptomatic. Diagnosis is made by testing those at risk for HCV RNA by polymerase chain reaction (PCR) and HCV antibody (anti-HCV) by enzyme immunoassay (EIA). The clinical impact of HCV infection is assessed by monitoring symptoms and signs, blood testing of liver enzymes, ultrasound imaging, and by liver biopsy. Improved efficacy and tolerability of treatment strategies in adults have had a significant impact on the management of children with HCV infection. The emphasis is now on promoting awareness, early diagnosis, and treatment. Treatment strategies have evolved from monotherapy with interferon alfa (IFNalpha), to combination therapy with ribavirin. Pegylated IFNalpha is superior to conventional IFNalpha, and forms the basis of current recommendations. The genotype of HCV influences treatment efficacy. Treatment is generally well tolerated in children, although adverse effects are common. Preparation and support throughout treatment for the whole family is needed. A proportion of children with HCV infection have co-morbidity, including viral co-infection or hematologic disease. Although treatment may be contraindicated, risks and benefits must be considered before denying treatment. Anemia is more common in those with HIV co-infection, renal insufficiency, thalassemia, or cirrhosis, and may be aggravated by treatment. Children with thalassemia may have iron overload, and transfusion requirements may increase during treatment. Further refinements of combination therapy and development of new drugs are in progress. Vaccine candidates are undergoing phase I and II treatment trials.

Current management of biliary atresia

Extra-hepatic biliary atresia occurs in approximately 1:15,000 live births leading to about 50 new cases/year in the UK. Presentation is with prolonged jaundice, usually in a term baby who develops signs of obstructive jaundice. Management has been improved by public and professional education to encourage early referral and diagnosis to facilitate initial surgery before 8 weeks of age. Surgical management is complementary and includes an attempt to restore biliary flow (the Kasai portoenterostomy) and liver transplantation if necessary. Medical management consists of antibiotics, ursodeoxycholic acid to encourage bile flow, fat soluble vitamin supplementation and nutritional support. Centralising surgery to specialised centres has improved survival of this potentially fatal disease to over 90% in the UK. Over half of infants undergoing portoenterostomy will clear the jaundice and have a greater than 80% chance of a good quality of life, reaching adolescence without transplantation. For those children developing intractable complications of cirrhosis and portal hypertension, liver transplantation provides a 90% chance of achieving normal life.

Improved outcome of referrals for intestinal transplantation in the UK

AIM

To describe the outcome of children with intestinal failure referred to Birmingham Children's Hospital (BCH) for consideration of intestinal transplantation (ITx), to determine factors for an adverse outcome and to analyse the impact of post-1998 strategies on survival.

SUBJECTS AND METHODS

A retrospective analysis was performed of children referred for ITx assessment from January 1989 to December 2003. Children were assessed by a multidisciplinary team and categorised into: (a) stable on parenteral nutrition; (b) unsuitable for transplantation (Tx); and (c) recommended for Tx. To analyse the impact of the post-1998 strategies on survival, a comparison was made between the two eras (pre-1998 and post-1998).

RESULTS

152 children with chronic intestinal failure were identified (63M:89F, median age 10 months (range 1-170)). After assessment, 69 children were considered stable on parenteral nutrition (5-year survival 95%); 28 children were unsuitable for Tx (5-year survival 4%); and 55 children were recommended for Tx (5-year survival 35%, which includes 14 children who died waiting for size-matched organs). Twenty three ITx and nine isolated liver transplants (iLTx) were performed. In a multivariate analysis, the following factors in combination had an adverse effect on survival: the presence of a primary mucosal disorder (p = 0.007, OR ratio 3.16, 95% CI 1.37 to 7.31); absence of involvement of a nutritional care team at the referring hospital (p = 0.001, OR ratio 2.55, 95% CI 1.44 to 4.52); and a serum bilirubin>100 micromol/l (p = 0.001, OR ratio 3.70, 95% CI 1.84 to 7.47). Earlier referral (median serum bilirubin 78 micromol/l in the post-1998 era compared with 237 micromol/l in the pre-1998 era, p = 0.001) may be a contributory factor to improved survival. The strategies of combined en bloc reduced liver/small bowel transplantation and iLTx resulted in fewer deaths on the waiting list in the post-1998 era (2 deaths in post-1998 era v 12 deaths in pre-1998 era). The overall 3-year survival in the post-1998 era (69%) has improved compared with the pre-1998 era (31%; p<0.001) CONCLUSION: The changing characteristics at the time of referral, including earlier referral and innovative surgical strategies have resulted in improved long-term survival of children referred for ITx.

Paediatric Hepatology Dependency score (PHD score): an audit tool

BACKGROUND

The aim was to develop a tool that measures patient dependency and disease severity in children with mild to severe liver disease.

METHODS

The initial pilot score was based on known markers of disease severity in acute and chronic liver disease. Between 1997 and 2001, the score was modified 4 times and reduced to comprise 10 key parameters: aspartate transaminase, prothrombin time, albumin, bilirubin, ascites, nutritional support, organ dysfunction, blood product support, sepsis and intravenous access. The score's face validity, internal consistency, interobserver agreement and construct validity were evaluated statistically and by the use of endpoints such as survival and transplant after 6 months.

RESULTS

The final 10 variable score was tested on 71 children admitted over two 3-month periods. The Cronbach's alpha score (a test for internal consistency) for the total score was 0.72. Serial data paralleled clinical deterioration and response to interventions. A Paediatric Hepatology Dependency score >15 had an odds ratio of 7 (P = 0.0125) for death or transplant at 6 months. The score was also found to agree with the paediatric end-stage liver disease score for the 12 patients being listed for liver transplantation (r = 0.660, P < 0.05).

CONCLUSION

The Paediatric Hepatology Dependency score is valid and internally consistent and is a convenient measure of dependency and disease severity in a heterogeneous group of patients with liver disease. It also allows admissions to be audited for comparison between eras and for monitoring the progress of patients while on the ward.

Skin surveillance of a U.K. paediatric transplant population

BACKGROUND

Solid organ transplant recipients are at increased risk of skin cancer. Melanoma is less common than nonmelanoma skin cancer (NMSC) although the relative proportion of melanoma among skin cancers has been shown to be higher in paediatric than adult recipients. Multiple melanocytic naevi and/or atypical naevi may be a risk factor for the development of melanoma. The relationship between naevus counts and phenotypic characteristics, disease-related variables and sun exposure has not been explored in paediatric transplant patients.

OBJECTIVES

To determine the prevalence of premalignant and malignant skin lesions and to identify known risk factors associated with benign and atypical melanocytic naevi in a U.K. paediatric transplant population.

METHODS

Paediatric (< or = 19 years) renal and liver transplant patients, who were 5 or more years post-transplantation, were reviewed over 12 months. Lifetime history of sun exposure, episodes of sunburn, sunny holidays, sunscreen use, sun bed use, demographic and transplantation details were collected using interview, questionnaire and case note review. A skin examination was performed for regional counts of malignant lesions, benign and atypical naevi.

RESULTS

Ninety-eight patients (82 liver, 13 renal, three multiorgan) with a median follow up of 9 years (range 5-16) were reviewed. Neither skin cancer nor premalignant lesions for NMSC were detected in this group. Eighty-five patients had benign naevi (median 6, range 1-57). Clinical risk factors for increased counts of benign naevi included increasing age (P = 0.03), more episodes of sunburn (P = 0.003) and prolonged treatment with cyclosporin (P = 0.009). The presence of atypical naevi in six patients was significantly associated with more episodes of sunburn (P = 0.006) and more transplants (P = 0.04). Other variables including phenotype, skin type, sun exposure, holidays abroad, residence abroad and total duration of immunosuppression did not correlate with benign or atypical naevus counts.

CONCLUSIONS

Skin cancer was not observed in paediatric solid organ transplant recipients who were 5-16 years post-transplantation. Both benign and atypical naevus counts were higher in children with frequent episodes of sunburn. As both naevi and sunburn are risk factors for melanoma, we should target fair-skinned transplant recipients with naevi for intensive sun avoidance education. A prospective, longitudinal follow-up study should determine the onset of skin cancer post-transplantation and the significance of benign and atypical naevus counts in this cohort.

The Meckel-Gruber Syndrome proteins MKS1 and meckelin interact and are required for primary cilium formation

Meckel-Gruber syndrome (MKS) is an autosomal recessive lethal malformation syndrome characterized by renal cystic dysplasia, central nervous system malformations (typically, posterior occipital encephalocele), and hepatic developmental defects. Two MKS genes, MKS1 and MKS3, have been identified recently. The present study describes the cellular, sub-cellular and functional characterization of the novel proteins, MKS1 and meckelin, encoded by these genes. In situ hybridization studies for MKS3 in early human embryos showed transcript localizations in agreement with the tissue phenotype of MKS patients. Both MKS proteins predominantly localized to epithelial cells, including proximal renal tubules and biliary epithelial cells. MKS1 localized to basal bodies, while meckelin localized both to the primary cilium and to the plasma membrane in ciliated cell-lines and primary cells. Meckelin protein with the Q376P missense mutation was unable to localize at the cell membrane. siRNA-mediated reduction of Mks1 and Mks3 expression in a ciliated epithelial cell-line blocked centriole migration to the apical membrane and consequent formation of the primary cilium. Co-immunoprecipitation experiments show that wild-type meckelin and MKS1 interact and, in three-dimensional tissue culture assays, epithelial branching morphogenesis was severely impaired. These results suggest that MKS proteins mediate a fundamental developmental stage of ciliary formation and epithelial morphogenesis.

The Budd-Chiari syndrome in children: the spectrum of management

The Budd-Chiari syndrome (BCS), characterized by hepatic venous outflow occlusion, is rare in children. We describe the cases of 3 patients with BCS who presented at different stages of liver dysfunction that required tailored management. A 10-year-old boy who presented with a weeklong history of abdominal discomfort received an early diagnosis. Treatment with thrombolytic therapy and adjunctive percutaneous interventional radiologic management led to a favorable outcome in this patient. A 2-year-old girl referred with a 6-week illness not amenable to thrombolytic therapy was managed with a pericardial patch atriocavoplasty to restore hepatic venous outflow tract patency. The third patient, a 5-year-old girl, presented with established cirrhosis and massive ascites. After we controlled the ascites with an extracorporeal shunt system and nutritional resuscitation, we conducted an orthotopic liver transplantation on this patient. The stage of disease at diagnosis influences the management strategy, and an early diagnosis offers patients the best possible chance of cure without major surgery. However, a later presentation can still be successfully managed by more radical surgical interventions. The aims of this case report were to emphasize the importance of a high index of suspicion in the diagnosis of pediatric BCS and to highlight the importance of early referral to a specialized pediatric liver unit with the necessary facilities to deal with the medical and surgical aspects of management.

Liver transplant in cystic fibrosis: a poll among European centers. A study from the European Liver Transplant Registry

Liver Transplant (LTx) has been rarely performed in cystic fibrosis (CF) patients and indications and outcomes are not well defined. A questionnaire was sent to all European CF and LTx centers to collect data on CF transplanted patients. We obtained information regarding 57 CF patients. LTx has been performed prevalently in males and in pediatric age. The main complication of cirrhosis was portal hypertension with hypersplenism. In the majority of cases the decision to transplant was based on the contemporary presence of various factors. Post-LTx survival was high and comparable with that expected for more common pediatric LTx indications. Poor respiratory function was the main risk factor for early death. In the short-term, respiratory function significantly improved after LTx. LTx is the appropriate treatment for patients with advanced CF-related liver disease and preserved pulmonary function (Forced Expiratory Volume at 1 s, FEV(1) >50%). This poll reveals that most European liver centers perform LTx prior to the development of end-stage liver disease or overt pulmonary or other clinical decompensation.

Clinical and molecular genetic features of ARC syndrome

Arthrogryposis, renal dysfunction and cholestasis (ARC) syndrome (MIM 208085) is an autosomal recessive multisystem disorder that may be associated with germline VPS33B mutations. VPS33B is involved in regulation of vesicular membrane fusion by interacting with SNARE proteins, and evidence of abnormal polarised membrane protein trafficking has been reported in ARC patients. We characterised clinical and molecular features of ARC syndrome in order to identify potential genotype-phenotype correlations. The clinical phenotype of 62 ARC syndrome patients was analysed. In addition to classical features described previously, all patients had severe failure to thrive, which was not adequately explained by the degree of liver disease and 10% had structural cardiac defects. Almost half of the patients who underwent diagnostic organ biopsy (7/16) developed life-threatening haemorrhage. We found that most patients (9/11) who suffered severe haemorrhage (7 post biopsy and 4 spontaneous) had normal platelet count and morphology. Germline VPS33B mutations were detected in 28/35 families (48/62 individuals) with ARC syndrome. Several mutations were restricted to specific ethnic groups. Thus p.Arg438X mutation was common in the UK Pakistani families and haplotyping was consistent with a founder mutation with the most recent common ancestor 900-1,000 years ago. Heterozygosity was found in the VPS33B locus in some cases of ARC providing the first evidence of a possible second ARC syndrome gene. In conclusion we state that molecular diagnosis is possible for most children in whom ARC syndrome is suspected and VPS33B mutation analysis should replace organ biopsy as a first line diagnostic test for ARC syndrome.

Immunosuppression in infants with short bowel syndrome undergoing isolated liver transplantation

BACKGROUND

Little data exist on immunosuppressive drug absorption in children with short bowel syndrome and intestinal failure associated liver disease (SBS-IFALD).

AIM

To evaluate the absorption of immunosuppressive medications in children with SBS-IFALD undergoing isolated liver transplantation (iLTx).

METHODS

A retrospective review was performed in children with SBS-IFALD undergoing LTx and comparison made with weight, age-matched children undergoing iLTX (extra-hepatic biliary atresia (EHBA) and normal intestinal length and function).

RESULTS

Seven children with SBS-IFALD undergoing iLTx (median residual bowel length, 60 cm, range 40-80) were compared with 15 children undergoing LTx for EHBA. SBS-IFALD children had significantly lower trough tacrolimus levels at three months (5.8 vs. 7.9 ng/mL, p<0.05) and six months (5.0 vs. 8.0 ng/mL, p<0.05), but equivalent levels at 12 months after iLTx. The median calculated dose-normalized concentrations indicated that systemic availability of tacrolimus was comparable in two groups at 3, 6, 12 months (33.1 vs. 23.3; 42.4 vs. 36; 51 vs. 52.9) despite the differences in enteral function. The incidence of acute rejection was 1/7 (SBS-IFALD) and 10/15 (EHBA) group (p = 0.06).

CONCLUSION

Children with SBS-IFALD demonstrated adequate absorption of oral tacrolimus without significant acute rejection rate after iLTx suggesting that modification of immunosuppression is not necessary.

Perinatal hepatitis C virus infection: diagnosis and management

Hepatitis C virus (HCV) infection in children is becoming an increasing challenge to health professionals. As our understanding of the disease evolves, so must our diagnostic and management strategies. In the 1990s, when HCV testing became available, children identified with HCV infection in the UK were mostly those who had required blood products, particularly those with haematological disorders. Acquiring knowledge of the natural history of HCV infection was confounded by the co-morbidity of iron overload, viral co-infection, and chemotherapy.

Current issues in pediatric transplantation

Pediatric solid organ transplantation is so successful that >80% of children will survive to become teenagers and adults. Therefore, it is essential that these children maintain a good quality life, free of significant long-term side effects. While intensive immunosuppressive regimens (containing CsA, tacrolimus, MMF, and steroids) effectively reduce acute or chronic rejection, they can produce long-term side effects including viral infection, renal dysfunction, hypertension, and stunting. The development of effective methods of diagnosis, prevention, and treatment of CMV means that this is no longer a significant cause of mortality, but morbidity remains high. In contrast, infection rates of EBV remain high in EBV-negative pre-transplant patients. However, pre-emptive reduction of immunosuppression or treatment with rituximab or adoptive T-cell therapy is effective in preventing/treating post-transplant lymphoproliferative disease. Recent protocols have concentrated on reducing CsA immunosuppression, to prevent unacceptable cosmetic effects, and to reduce the hypertension, hyperlipidemia, and nephrotoxicity. Both CsA and tacrolimus cause a 30% reduction in renal function, with 4-5% of patients developing severe chronic renal failure. The use of IL-2 inhibitors for induction therapy with low-dose calcineurin inhibitors, in combination with renal-sparing drugs such as MMF or sirolimus for maintenance immunosuppression, should prevent significant renal dysfunction in the future. The concept of steroid-free immunosuppression with IL-2 inhibitors, tacrolimus, and MMF is an attractive option, which may reduce stunting and renal dysfunction. However, these regimens may be associated with the increased development of de-novo autoimmune hepatitis in 2-3% of children. The most important challenge to long-term survival in transplanted children is the management of non-adherence and other adolescent issues, particularly when transferring to adult units, as this is the time when many successful transplant survivors lose their grafts.

An Economic Evaluation of Pediatric Small Bowel Transplantation in the United Kingdom

BACKGROUND

Small bowel transplantation (SBTx) offers an alternative to parenteral nutrition (PN) for the treatment of chronic intestinal failure in children: this study estimated its cost-effectiveness in the early phase of a U.K. program.

METHODS

Children assessed for SBTx were categorized as: 1) requiring SBTx following PN-related complications (n=23), 2) stable at home not requiring SBTx (n=24), and 3) terminally ill and unsuitable for SBTx (n=6). Costs were estimated from detailed resource-use data. Two comparisons were used for effectiveness: actual survival following transplantation (n=14) compared to: 1) estimated survival without transplantation using a prognostic model, and 2) the waiting list experiences of all patients listed for SBTx (n=23).

RESULTS

Mean costs up to 30 months were pounds sterling 207,000 for those transplanted or on the waiting list, pounds sterling 159,000 for those stable on home PN, and pounds sterling 56,000 for those terminally ill. The prognostic model estimated a mean survival gain from transplantation of 0.12 years over 30 months, and suggested that transplantation was cost-saving. The second approach suggested that transplantation reduced survival by 0.24 years at an additional cost of pounds sterling 131,000.

CONCLUSIONS

Firm conclusions on cost-effectiveness of SBTx are not possible given the two different estimates. The prognostic model approach (suggesting that pediatric SBTx may provide a small survival benefit at a small reduction in costs) should be less subject to bias, but the model requires external validation. Meanwhile, children at risk of fatal PN-complications should be given the opportunity to receive a SBTx only within a continuing formal assessment of the technology.

Is Serum Gentamicin Level a Good Predictor of Graft Injury in Intestinal Transplantation?

INTRODUCTION

Following intestinal transplant (SBT), the early diagnosis and treatment of rejection is a major management aim. The diagnosis of rejection is based on histology of stomal biopsies. Oral gentamycin (2.5 mg/kg) was used for selective decontamination of the digestive system. Our hypothesis was that gentamycin might be absorbed in the presence of graft dysfunction.

AIM

Our goal was to assess the correlation between serum gentamycin level and the health of the intestinal graft.

SUBJECTS AND METHODS

Among 33 SBT performed from 1993 to 2005, serum gentamycin levels were performed once weekly or more often when there was a suspicion of rejection. All data were analyzed retrospectively.

RESULTS

Adequate trough levels were achieved for only 23 patients, six of whom had histologically proven rejection and only one did not have a raised gentamycin content. Five patients with raised levels but no rejection included two with severe intestinal ischemia and three with bowel obstruction/ileus. Four of the five patients required laparotomies.

CONCLUSION

We concluded that in our study raised serum gentamycin levels were a good predictor of rejection or significant injury to the graft.

Paracetamol induced hepatotoxicity

AIM

To identify the clinical and biochemical risk factors associated with outcome of paracetamol induced significant hepatotoxicity in children.

METHODS

Retrospective case notes review of those with paracetamol overdose admitted from 1992 to 2002. Patients were analysed in two groups: group I recovered after conservative treatment and group II developed progressive liver dysfunction and were listed for liver transplantation.

RESULTS

Of 51 patients (6 males, 45 females, aged 0.8-16.1 years), 6 (aged <7 years) received cumulative multiple doses, and 45 a single large overdose (median 345 mg/kg, range 91-645). The median (range) interval to hospital at presentation post-ingestion was 24 hours (4-65) and 44 hours (24-96) respectively in groups I and II. Patients received standard supportive treatment including N-acetylcysteine. All children in group I survived. In group II, 6/11 underwent orthotopic liver transplantation (OLT) and 2/6 survived; 5/11 died awaiting OLT. Cerebral oedema was the main cause of death. Children who presented late to hospital for treatment and those with progressive hepatotoxicity with prothrombin time >100 seconds, hypoglycaemia, serum creatinine >200 micromol/l, acidosis (pH <7.3), and who developed encephalopathy grade III, had a poor prognosis or died. Although hepatic transaminase levels were markedly raised in both groups, there was no correlation with necessity for liver transplantation or death.

CONCLUSION

Accidental or incidental paracetamol overdose in children may be associated with toxic liver damage leading to fulminant liver failure. Delayed presentation and/or delay in treatment, and hepatic encephalopathy > or =grade III were significant risk factors, implying poor prognosis and need for OLT. Prompt identification of high risk patients, referral to a specialised unit for management, and consideration for liver transplantation is essential.

Progressive histological damage in liver allografts following pediatric liver transplantation

The long-term histological outcome after pediatric liver transplantation (OLT) is not yet fully understood. De novo autoimmune hepatitis, consisting of histological chronic hepatitis associated with autoantibody formation and allograft dysfunction, is increasingly recognized as an important complication of liver transplantation, particularly in the pediatric population. In this study, 158 asymptomatic children with 5-year graft survival underwent protocol liver biopsies (113, 135, and 64 at 1, 5, and 10 years after OLT, respectively). Histological changes we re correlated with dinical,biochemical, and serological findings. All patients received cydosporine A as primary immunosuppression with withdrawal of corticosteroids at 3 months post OLT. Normal or near-normal histology was reported in 77 of 113 (68%), 61 of 135 (45%), and 20 of 64 (31%) at 1, 5, and 10 years, respectively. The commonest histological abnormality was chronic hepatitis (CH), the incidence of which increased with time [25/113 (22%), 58/135 (43%), and 41/64 (64%) at 1, 5, and 10 years, respectively) (P < .0001)]. The incidence of fibrosis associatedwith CH increasedwith time [13/25 (52%), 47/58 (81%), and 37/41 (91%) at 1, 5, and 10 years, respectively) (P < .0001)]. The severity of fibrosis associated with CH also increased with time, such that by 10 years 15% had progressed to cirrhosis. Aspartate aminotransfemse (AST) levels were slightly elevated in children with CH (median levels 52 IU/L, 63 IU/L, and 48 IU/L at 1, 5, and 10 years, respectively), but this did not reach statistical significance compared with those with normal histology. On multivariate analysis, the only factor predictive of chronic hepatitis was autoantibody positivity (present in 13% and 10% of children with normal biopsies at 5 and 10 years, respectively, and 72% and 80% of those with CH at 5 and 10 years, respectively) (P < .0001). Four children with CH and autoantibodies, who also had raised immunoglobulin G (IgG) levels and AST greater than 1.5 x normal fulfilled the diagnostic criteria for de novo autoimmune hepatitis (AIH). Another two were found to be hepatitis C positive. No definite cause for CH could be identified in the other cases. In condusion, chronic hepatitis is a common finding in children after liver transplantation and is associated with a high risk of developing progressive fibrosis, leading to cirrhosis. Standard liver biochemical tests cannot be relied on either in the diagnosis or in the monitoring of progress of chronic allograft hepatitis. In contrast, the presence ofautoantibodies is strongly associated with the presence of CH. The cause of chronic hepatitis in transplanted allografts is uncertain but may be immune mediated, representing a hepatitic form of chronic rejection.

Current issues in the management of intestinal failure

Successful long term parenteral nutrition has transformed the prognosis for children with irreversible intestinal failure in the last three decades, but has also highlighted the long term complications: intestinal failure associated liver disease; recurrent catheter sepsis; and impaired venous access. Recent advances in small bowel transplantation and non-transplant surgical techniques now offer hope of sustained survival in the future without parenteral nutrition.

Cardiomyopathy in tyrosinaemia type I is common but usually benign

Tyrosinaemia type I (TTI) is an inherited multisystemic disorder of tyrosine metabolism. In addition to hepatic and renal involvement, cardiomyopathy is an important clinical manifestation.

OBJECTIVE

To evaluate the incidence and outcome of cardiomyopathy in TTI.

SUBJECTS AND METHODS

A retrospective study was performed of 20 consecutive children with TTI (12 male, 8 female) referred to a single centre between 1986 and 2002. All were initially treated with standard dietary therapy and, since 1992, with nitisinone. The indications for orthotopic liver transplantation (LT) changed during the study. Serial echocardiography was undertaken in all subjects.

RESULTS

9/20 (45%) children had an acute hepatic presentation. Five (25%) received dietary treatment followed by LT, and 14 (70%) were treated with nitisinone at presentation. 6/20 (30%) had cardiomyopathy at initial assessment, with interventricular septal hypertrophy being the commonest finding (5/6). Cardiomyopathy was significantly less common in those treated initially with nitisinone. After a median follow-up of 3.6 (0.45-13.5) years, 5/6 (83%) had complete resolution of cardiomyopathy and 1/6 showed significant improvement. No child with a normal initial echocardiography subsequently developed cardiomyopathy.

CONCLUSION

Cardiomyopathy is a common manifestation of TTI and it has a favourable long-term outcome. Children initially treated with nitisinone are less likely to develop this complication.

Long-term lamivudine therapy for children with HBeAg-positive chronic hepatitis B

One year of lamivudine treatment results in increased hepatitis B e antigen (HBeAg) seroconversion and serum hepatitis B virus (HBV) DNA negativity in children with chronic hepatitis B and high serum alanine aminotransferase concentrations. Two hundred seventy-six children who participated in a 1-year randomized, placebo-controlled study of lamivudine were enrolled in a 24-month, open-label extension. Patients were stratified into two groups based on HBeAg status at week 48 of the previous study: 213 HBeAg-positive children were entered into a treatment arm, and 63 HBeAg-negative children were entered into an observation arm to evaluate durability of HBeAg loss. In the treatment arm, 28 of 133 (21%) children previously treated with lamivudine and 23 of 77 (30%) children who previously received placebo achieved the primary end point: virological response (VR) (HBeAg loss and HBV DNA negativity) at month 24. The incidence of YMDD (tyrosine, methionine, aspartate, aspartate) mutations at month 24 was 64% (66/103) in the children previously treated with lamivudine and 49% (34/70) in those previously treated with placebo. The incidence of VR at month 24 was 5% (5/100) for patients with YMDD mutant HBV and 54% (39/72) for patients without. The durability of response in the observation arm was 89% (48/54) at month 24. In conclusion, further clinical response was seen over the 24-month open-label study period in children who had not initially achieved a VR after 12 months of lamivudine treatment. However, the incidence of YMMD mutations increased over time and resulted in lower response rates. VR was maintained in most patients who had initially responded to lamivudine in the first 12 months.

Intestinal failure-associated liver disease: what do we know today?

Intestinal failure-associated liver disease develops in 40% to 60% of infants who require long-term total parenteral nutrition (TPN) for intestinal failure and 15% to 40% of adults on home parenteral nutrition. The clinical spectrum includes hepatic steatosis, cholestasis, cholelithiasis, and hepatic fibrosis. Progression to biliary cirrhosis and the development of portal hypertension and liver failure occurs in a minority but is more common in infants and neonates than in adults. The pathogenesis is multifactorial. In infants it is related to prematurity, low birth weight, duration of PN, short bowel syndrome requiring multiple laparotomies, and recurrent sepsis. Other important mechanisms include lack of enteral feeding, which leads to reduced gut hormone secretion; reduction of bile flow and biliary stasis, which leads to the development of cholestasis; and biliary sludge and gallstones, which exacerbate hepatic dysfunction. In adults, IFALD is less common and related to age, length of time on PN, total caloric intake, and lipid or glucose overload. In preterm infants, a deficiency of taurine or cysteine may play a role, whereas in both adults and children, choline deficiency may exacerbate IFALD. Lipid emulsions, choline deficiency, and manganese toxicity are associated with both hepatic steatosis and cholestasis in adults and children. Management strategies for the prevention of intestinal failure-induced liver disease include early enteral feeding, a multidisciplinary approach to the management of parenteral nutrition, and aseptic catheter techniques to reduce sepsis. The addition of choline, taurine, and cysteine to PN solutions may also play a role. Oral administration of ursodeoxycholic acid may improve bile flow and reduce gallbladder stasis. Survival after either isolated small bowel or combined liver and small bowel transplantation is approximately 50% at 5 years, making this an acceptable therapeutic option in adults and children with irreversible liver and intestinal failure.

The transmembrane protein meckelin (MKS3) is mutated in Meckel-Gruber syndrome and the wpk rat

Meckel-Gruber syndrome is a severe autosomal, recessively inherited disorder characterized by bilateral renal cystic dysplasia, developmental defects of the central nervous system (most commonly occipital encephalocele), hepatic ductal dysplasia and cysts and polydactyly. MKS is genetically heterogeneous, with three loci mapped: MKS1, 17q21-24 (ref. 4); MKS2, 11q13 (ref. 5) and MKS3 (ref. 6). We have refined MKS3 mapping to a 12.67-Mb interval (8q21.13-q22.1) that is syntenic to the Wpk locus in rat, which is a model with polycystic kidney disease, agenesis of the corpus callosum and hydrocephalus. Positional cloning of the Wpk gene suggested a MKS3 candidate gene, TMEM67, for which we identified pathogenic mutations for five MKS3-linked consanguineous families. MKS3 is a previously uncharacterized, evolutionarily conserved gene that is expressed at moderate levels in fetal brain, liver and kidney but has widespread, low levels of expression. It encodes a 995-amino acid seven-transmembrane receptor protein of unknown function that we have called meckelin.

Long-term follow-up of hepatitis B carrier children treated with interferon and prednisolone

The long-term outcome of treatment with Interferon Alpha 2B with and without Prednisolone priming in children infected perinatally with hepatitis B was reviewed. The group studied included 48 children (aged 2-16 years), who were HBe antigen and hepatitis B DNA positive between 1991 and 1993. Twenty children were randomized to a therapeutic trial at that time, and received Prednisolone in reducing doses for 6 weeks and Interferon for 16 weeks while 22 children were monitored without treatment for 12 months. Fourteen of the untreated group and 6 additional children later received treatment with Interferon alone (n = 20). Eight children for whom treatment was declined were followed long term. Median follow-up was 7.5 years (range 1.5-10.6). There was no significant effect of Interferon therapy on seroconversion with or without Prednisolone at 12 months post-treatment compared to untreated children. On longer term follow-up, the 5-year HBeAg to anti-HBe seroconversion percentages, estimated from Kaplan-Meier curves, were 54% for Prednisolone plus Interferon, 22% for Interferon alone, and 12% for untreated children. The median time to seroconversion was 3.9 years (range 0.4-8.2) and was shortest in those treated with Prednisolone plus Interferon. Children who had elevated hepatic transaminase enzymes prior to treatment or during Prednisolone priming had a better response. In contrast to many European studies, no child cleared HBsAg and produced anti-HBs. Treatment with Prednisolone priming and Interferon, improved both the time and rate of seroconversion compared to no treatment or Interferon alone, suggesting that this combination of drugs might have an immunomodulatory effect.

Interferon alfa-2b in combination with ribavirin for the treatment of chronic hepatitis C in children: efficacy, safety, and pharmacokinetics

Chronic hepatitis C virus (HCV) infection is usually asymptomatic in children, but significant liver disease may occur. We evaluated the efficacy, safety, and pharmacokinetics of interferon alfa-2b and ribavirin in children with chronic HCV. We determined the optimal ribavirin dose in an initial cohort of a phase 1 study and then subsequently used it, in combination with interferon alfa-2b, in a second cohort of this study and a phase 3 trial. The primary efficacy endpoint in all studies was sustained virological response, defined by undetectable serum HCV RNA 24 weeks after completion of therapy. All efficacy and safety analyses were performed on the intent-to-treat population. Children receiving interferon alfa-2b plus ribavirin 15 mg/kg/d in the phase 1 study had the maximum reduction in serum HCV RNA at treatment weeks 4 and 12 with an acceptable safety profile. This ribavirin dose was selected as optimal and used in all subsequent studies. In all, 46% (54/118) of optimally treated children achieved sustained virological response. Sustained virological response was significantly higher in children with HCV genotype 2/3 (84%) than in those with HCV genotype 1 (36%). Adverse events led to dose modification in 37 (31%) and discontinuation in 8 (7%). Multiple-dose interferon alfa-2b and ribavirin peak and trough concentrations and area-under-the-curve were similar between children and adults. In conclusion, interferon alfa-2b in combination with ribavirin is effective and safe in children with chronic hepatitis C virus.

Mycophenolate mofetil for renal dysfunction after pediatric liver transplantation

BACKGROUND

Cyclosporine A (CsA) and tacrolimus (Tac) provide effective immunosuppression after orthotopic liver transplantation (OLT) but can cause renal dysfunction that may progress to end-stage renal failure (ESRF). Mycophenolate mofetil (MMF) is a newer immunosuppressant that does not affect renal function. Its long-term use in children with renal dysfunction after OLT has not yet been fully evaluated.

METHODS

A retrospective analysis was performed of all children begun on MMF for renal dysfunction and followed up for at least 1 year. Renal dysfunction was defined as calculated glomerular filtration rate (cGFR) of less than 65 mL/min/1.73 m2. cGFR and liver function were measured before and after transfer. Data were analyzed using the Wilcoxon signed rank test.

RESULTS

Forty-eight children (23 males) began MMF at a median age of 11.1 (0.9-18.1) years and at a median of 4.0 (0.3-12.4) years postOLT. Median baseline cGFR was 54 (range 29-65) mL/min/1.73 m2. Immunosuppression after transfer was MMF monotherapy in 36, MMF with steroids, in 4 and MMF with low-dose CsA or Tac in 8. In 44 (92%) patients, there was a statistically significant increase to a median cGFR of 69 (28-114) mL/min/1.73 m2 by 1 month and a further increase to a median cGFR of 77 (24-105) mL/min/1.73 m2 by 2 months of MMF treatment, after which time cGFR was maintained. Children aged less than 3 years at OLT or who were less than 5 years postOLT when MMF was begun demonstrated greater increases in cGFR. Four children with a median baseline cGFR of 34 (range 31-49) mL/min/1.73 m2 did not respond and progressed to ESRF. Mild side effects occurred in seven (15%) and gastrointestinal bleeding requiring discontinuation of MMF in one (2%). Liver function abnormalities occurred in seven (15%): transient transaminitis in three, acute rejection in two, and chronic rejection in two, of whom one required retransplantation.

CONCLUSIONS

In 92% children with renal dysfunction after OLT, MMF treatment provided safe and effective immunosuppression and allowed CsA or Tac to be discontinued or reduced, leading to improvement of renal function. The improvement was greatest in younger children and those who began MMF early postOLT. Side effects were uncommon. Additional steroid cover during the transfer to MMF should be considered to prevent liver-allograft rejection.

Comparative evolutionary analysis of VPS33 homologues: genetic and functional insights

VPS33B protein is a homologue of the yeast class C vacuolar protein sorting protein Vps33p that is involved in the biogenesis and function of vacuoles. Vps33p homologues contain a Sec1 domain and belong to the family of Sec1/Munc18 (SM) proteins that regulate fusion of membrane-bound organelles and interact with other vps proteins and also SNARE proteins that execute membrane fusion in all cells. We demonstrated recently that mutations in VPS33B cause ARC syndrome (MIM 208085), a lethal multisystem disease. In contrast, mutations in other Vps33p homologues result in different phenotypes, e.g. a mutation in Drosophila melanogaster car gene causes the carnation eye colour mutant and inactivation of mouse Vps33a causes buff hypopigmentation phenotype. In mammals two Vps33p homologues (e.g. VPS33A and VPS33B in humans) have been identified. As comparative genome analysis can provide novel insights into gene evolution and function, we performed nucleotide and protein sequence comparisons of Vps33 homologues in different species to define their inter-relationships and evolution. In silico analysis (a) identified two homologues of yeast Vps33p in the worm, fly, zebrafish, rodent and human genomes, (b) suggested that Carnation is an orthologue of VPS33A rather than VPS33B and (c) identified conserved candidate functional domains within VPS33B. We have shown previously that wild-type VPS33B induced perinuclear clustering of late endosomes and lysosomes in human renal cells. Consistent with the predictions of comparative analysis: (a) VPS33B induced significantly more clustering than VPS33A in a renal cell line, (b) a putative fly VPS33B homologue but not Carnation protein also induced clustering and (c) the ability to induce clustering in renal cells was linked to two evolutionary conserved domains within VPS33B. One domain was present in VPS33B but not VPS33A homologues and the other was one of three regions predicted to form a t-SNARE binding site in VPS33B. In contrast, VPS33A induced significantly more clustering of melanosomes in melanoma cells than VPS33B. These investigations are consistent with the hypothesis that there are two functional classes of Vps33p homologues in all multicellular organisms and that the two classes reflect the evolution of organelle/tissue-specific functions.

Hyperinsulinism in tyrosinaemia type I

Tyrosinaemia type I (TT I) (McKusick 276700) is a heterogeneous disorder with a broad spectrum of clinical phenotypes. Although histological abnormalities of the pancreas are well recognized, there are only incidental reports of pancreatic dysfunction manifested as insulin-dependent diabetes mellitus. We report three subjects with TT I and acute liver dysfunction who had hyperinsulinism in early infancy. Hypoglycaemia persisted despite dietary treatment and one patient had inadequate lipolysis at the time of hypoglycaemia. All three patients were successfully treated with diazoxide (10 mg/kg per day) and chlorthiazide (35 mg/kg per day) and treatment was gradually withdrawn after 9, 13 and 34 months, respectively. The mechanism of pancreatic dysfunction in TT I is unknown but may be related to the toxic metabolites that accumulate in this condition. We conclude that hyperinsulinism is not a rare complication in TT I. In patients with persistent hypoglycaemia, C-peptide should always be measured. Treatment with diazoxide and chlorthiazide is highly effective, appears to be safe, and does not need to be continued lifelong.

Turtle and mammal penis designs are anatomically convergent

Males in many modern amniote taxa have a hydraulic penis that inflates for copulation. Hydraulic skeletons are typically reinforced with inextensible fibres; the specific arrangement of the fibres within the skeleton determines whether it is flexible or resists bending. I show that the hydraulic skeleton in the turtle penis is reinforced by an axial orthogonal array of collagen fibres. This microanatomy is evolutionarily convergent with that of mammalian penises, and implies that there is a limited number of mechanical designs for an inflatable structure with high bending stiffness.

The role of Notch receptor expression in bile duct development and disease

Mutations in the Jagged1 gene, a ligand for the Notch signalling pathway, have been implicated in the pathogenesis of Alagille syndrome (AGS), resulting in bile duct paucity. Recently, a mouse model for AGS suggested that abnormalities of the Notch2 receptor, as well as of Jagged1, may be present. Expression patterns of Notch receptors have not been described in the developing human liver or in paediatric liver. The expression of Notch receptors and ligands was examined in fetal, paediatric normal, and diseased human liver by RT-PCR and immunohistochemistry. RT-PCR showed Notch1-4 mRNA expression to be present. In fetal liver, Notch3 protein was expressed on mesenchymal cells, closely adjacent to ductal plate cells that expressed Jagged1. In paediatric normal liver, Notch1 and Notch2 were present on mature bile duct cells. Notch expression was altered in disease, with distinct differences in AGS from extrahepatic biliary atresia (EHBA) and alpha1-anti-trypsin deficiency (alpha1AT). In AGS, where extensive ductular reaction was present, Jagged1 was expressed on ductular reactive cells (DRCs), along with marked Notch2 and Notch3 staining. Where there was ductular paucity, Notch2 and Notch3 were not expressed on remaining biliary epithelial cells. In EHBA and alpha1AT, Notch receptor expression was not seen on DRCs. Instead, Notch2 and Notch3 were expressed by stromal cells. In all diseases, Notch3 was expressed on neovessels in portal tracts and cirrhotic fibrous septa. In conclusion, Notch3 is expressed in close proximity to Jagged1 at the time of ductal plate formation, suggesting that Notch3 is important for bile duct development. The expression of both Notch2 and Notch3 in AGS on DRCs confirms that these receptors may be important in the pathogenesis of this disease. Further studies are required to investigate the presence of Notch2 and Notch3 at other periods in liver development and to clarify the role of Notch signalling in paediatric cholestases.

Natural history of hepatitis B in perinatally infected carriers

OBJECTIVES

To establish natural seroconversion rates and incidence of hepatic pathology in perinatally infected hepatitis B carriers.

METHODS

Seventy three perinatally infected hepatitis B carriers identified through maternal screening were evaluated. Fifty three were born to parents from the Indian subcontinent, nine were Oriental, six were Afro-Caribbean, and five were white. Median follow up was 10.24 (range 2.02-20.16) years.

RESULTS

Only three of the children followed up had cleared hepatitis B surface antigen during this period, and 30% of the children had seroconverted to anti-HBe. Seroconversions to anti-HBe were observed in Asian (18/50) and white (4/5) children, but not in Oriental or Afro-Caribbean children. More girls (40%) than boys (23%) had seroconverted, but the difference was not significant. All children were asymptomatic with normal physical examination, growth, and development. Almost half (48%) of the hepatitis B e antigen (HBeAg) positive children had normal hepatic transaminases and liver function. Thirty five liver biopsies were performed in children with active virus replication (HBeAg or hepatitis B virus DNA positive) who were being considered for antiviral treatment as part of a clinical trial and were scored using the Ishak method. Two thirds (62%) of the children had mild hepatitis, 60% had mild fibrosis, and 18% had moderate to severe fibrosis. There was a weak correlation between histological evidence of hepatitis and hepatic transaminase activity, implying that biochemical monitoring of hepatic disease activity may be ineffective.

CONCLUSIONS

These asymptomatic hepatitis B virus carrier children remain infectious in the medium to long term with notable liver pathology. They should receive antiviral treatment to reduce infectivity and to prevent further progression of liver disease. Hepatic transaminases alone are not a reliable marker of liver pathology, and liver histology is essential before consideration for antiviral treatment.

Long-term persistence of immunity to hepatitis B after vaccination during infancy in a country where endemicity is low

BACKGROUND

The long-term response to hepatitis B vaccination during infancy has not been fully evaluated in countries where endemicity is low.

METHODS

The present study was a serological investigation of immunity to hepatitis B during adolescence. In a cohort of children who were born to hepatitis B virus carrier mothers and who were vaccinated during infancy, evidence of past or current infection and the response to a single booster dose of vaccine were analyzed. Sixty-four children whose antibody levels were measured after immunization (group 1) and 52 younger siblings who did not undergo postvaccination antibody tests (group 2) were studied.

RESULTS

One child in each group showed evidence of natural infection. In group 1, 32 children (50%) had undetectable antibody to hepatitis B surface antigen (anti-HBs), and only 8 (13%) had levels >100 mIU/mL. After a booster dose of vaccine, only 7 (11%) still had undetectable anti-HBs, 3 (5%) showed a primary response, and 50 (78%) had levels >100 mIU/mL. Five of the 7 vaccine nonresponders and all of the primary responders had also received hepatitis B-specific immunoglobulin (HBIG) at birth. The children in group 2 showed a similar response to the vaccine, but with slightly higher levels of anti-HBs.

CONCLUSIONS

Most children vaccinated at birth retain immunological memory to hepatitis B vaccine for 15 years, but those who did not were more likely to have received HBIG at birth, suggesting that passive antibody may interfere with the induction of immunological memory.

Population screening for neonatal liver disease: potential for a community-based programme

OBJECTIVES

To evaluate a community-based screening programme for detecting neonatal liver disease by the quantitation of conjugated bilirubin in blood.

SETTINGS AND METHODS

Prospective cohort/observational study using spare plasma from routinely collected liquid neonatal screening specimens from babies born in Birmingham over a two-year period. Babies with a conjugated bilirubin above 18 mumol/l and comprising more than 20% of the total bilirubin were followed up. A total of 27654 neonates were tested in the community, with a further 2425 samples from babies hospitalised at the time of the test.

RESULTS

In the community-based series, 84.7% of the specimens received were analysed, the remainder being unusable mainly because of gross haemolysis (8.6%) or insufficient sample (5.8%). In 107 neonates the results were above the cut-off limits (0.46% of the number analysed). Of these, 12 had persistently abnormal results, 11 of whom had confirmed liver disease. The liver diseases detected included neonatal hepatitis (n=6), extra-hepatic biliary atresia (n=2), hypopituitarism (n=1), alpha-1-antitrypsin deficiency (n=1) and Alagille syndrome (n=1). The sensitivity and specificity of the test for babies in the community were 100% and 99.6%, respectively.

CONCLUSIONS

Conjugated bilirubin in plasma measured at 6-10 days is a reliable marker for neonatal liver disease, and a population screening programme based on this method has the potential to improve the survival and quality of life of infants born with liver disease. However, testing as part of the neonatal screening programme will prove practical only if the method can be adapted to use dried blood spots.

Seamless management of biliary atresia in England and Wales (1999-2002)

BACKGROUND

Before 1999, infants born in the UK with suspected biliary atresia were investigated in regional centres, and, if confirmed, a Kasai operation was done there. Since 1999, all infants with suspected biliary atresia in England and Wales, UK, have been referred to one of three designated centres where both the Kasai operation and liver transplantation (if necessary) could be done.

METHODS

We assessed clearance of jaundice (bilirubin <20 micromol/L) as an early outcome in all cases of biliary atresia referred from one of the three centres. We then estimated survival using the Kaplan-Meier method with endpoints of liver transplantation or death.

FINDINGS

148 infants with biliary atresia were treated between January, 1999, and June, 2002. A primary portoenterostomy was done in 142 (96%) infants and a primary liver transplant in five (3%). One child died before any intervention. Early clearance of jaundice after portoenterostomy was achieved in 81 of 142 (57%) infants. Liver transplantation was done in 52 (37%) of those undergoing portoenterostomy. 13 (9%) infants died. Of the 135 children who survived, 84 (62%) still have their native liver and 51 (38%) had transplantation. The median follow-up of survivors was 2.13 (range 0.5-4.1) years. The overall 4-year estimated actuarial survival was 89% (95% CI 82-94). The 4-year estimated actuarial survival with native liver was 51% (42-59%).

INTERPRETATION

Our early results suggest that surgical outcome can be improved by centralisation of care to supra-regional centres.

Ultraviolet-radiation-induced erythema and suppression of contact hypersensitivity responses in patients with polymorphic light eruption

Ultraviolet-radiation suppresses cell-mediated immunity in healthy humans. It has been postulated that, in the short term, this immunosuppression prevents autoimmune responses to ultraviolet-radiation damaged skin. Patients with polymorphic light eruption (PLE) demonstrate abnormal responses to ultraviolet-radiation suggestive of an immune response to an ultraviolet-radiation-induced antigen. We investigated whether PLE patients (n=22) were resistant to ultraviolet-radiation-induced immunosuppression compared to skin-type, aged-matched controls (n=23). Groups of patients and controls (six subjects per group) received a single dose of solar-simulated ultraviolet-radiation of either 0, 0.6, 1 or 2 minimal erythema doses (MED). Erythema was quantified using a reflectance meter and all volunteers were sensitised on the irradiated site with dinitrochlorobenzene. Contact hypersensitivity responses (CHS) to dinitrochlorobenzene were quantified after challenge using ultrasound. Ultraviolet-radiation-induced erythema was comparable in patients and controls. CHS was comparable in unirradiated patients and controls. UVR-induced a dose-dependent suppression of CHS in all volunteers but patients were more resistant to immunosuppression after 1MED. Exposure to 1MED suppressed CHS by 78% in controls but induced less suppression in patients (44%, p < 0.01). Our data suggest that PLE patients have a flaw in their immunoregulatory response to ultraviolet-radiation it is only apparent over a narrow dose range around 1 MED.

Fatal and life threatening rupture of splenic artery aneurysms in children with portal hypertension

Aneurysms of the splenic artery (SAAs) are a rare complication of portal hypertension in adults. Although the risk of rupture is small, associated mortality is high. Furthermore, circulatory changes that occur following liver transplantation (OLT) may increase the risk of SAA rupture. The incidence in children with portal hypertension is unknown and thus we present our experience with two children who had ruptured SAA, one of whom died. Although there are no accepted methods for routine screening, hepatic angiography should be considered in children with long-standing portal hypertension (more than 10 yr), in order to detect and consider resection of the aneurysms, either before or at the time of liver transplantation.

The effect of long-term calcineurin inhibitor therapy on renal function in children after liver transplantation

Calcineurin inhibitor drugs (CNI), cyclosporin and tacrolimus are potent immunosuppressants, which have improved survival after liver transplantation. We evaluated long-term renal function in children receiving calcineurin inhibitors after liver transplantation. A retrospective analysis of all children undergoing orthotopic liver transplantation (OLT) from 1989 to 1999 who survived 1-yr post-transplantation was performed. All received prednisolone and either cyclosporin and azathioprine or tacrolimus. Steroids were withdrawn at 3 months and cyclosporin/tacrolimus monotherapy was initiated 12 months post-OLT. Calculated glomerular filtration rate (cGFR) was calculated using the modified Counahan-Barratt formula and measured pretransplant, 3, 6 and 12 months post-transplant and annually thereafter. Data were analysed in a serial manner to evaluate the trend of cGFR over time selectively using the Wilcoxon signed rank test and paired t-tests as appropriate. A total of 113 patients (65 males:48 females) were followed up for more than 1 yr (maximum 5 yr). Median (range) age at transplantation was 26 months (3-177). There was a significant fall of 35% in cGFR at 3 months compared with the pretransplant value (p = 0.001). By 12 months following the reduction in immunosuppression dosage, renal function stabilized with a slight improvement in cGFR which reached 76% of the pretransplant value at 5 yr (p < 0.001). Children who were <1 yr of age at the time of OLT had better recovery of renal function than older children (p = 0.02). No association was seen with sex, the type of immunosuppression or the underlying diagnosis. Renal dysfunction is a known complication of CNI therapy. Despite an initial reduction in cGFR, which was associated with maximal immunosuppression, long-term low dose CNI therapy was not associated with continued deterioration of renal function, particularly in children who were transplanted as infants.

Mutations in VPS33B, encoding a regulator of SNARE-dependent membrane fusion, cause arthrogryposis-renal dysfunction-cholestasis (ARC) syndrome

ARC syndrome (OMIM 208085) is an autosomal recessive multisystem disorder characterized by neurogenic arthrogryposis multiplex congenita, renal tubular dysfunction and neonatal cholestasis with bile duct hypoplasia and low gamma glutamyl transpeptidase (gGT) activity. Platelet dysfunction is common. Affected infants do not thrive and usually die in the first year of life. To elucidate the molecular basis of ARC, we mapped the disease to a 7-cM interval on 15q26.1 and then identified germline mutations in the gene VPS33B in 14 kindreds with ARC. VPS33B encodes a homolog of the class C yeast vacuolar protein sorting gene, Vps33, that contains a Sec1-like domain important in the regulation of vesicle-to-target SNARE complex formation and subsequent membrane fusion.

Transitioning care of the pediatric recipient to adult caregivers

The development of transitional care is one of the major challenges for the twenty-first century as the survival rates and medical outcomes for child and adolescent recipients of solid organ transplants continue to improve. Such developments must include pediatric and adult care providers and require training of professionals in both arenas. Transition is a process in which the transfer to adult care is only one event within that process. The key elements of transition for pediatric recipients are discussed, and the importance of a coordinated, structured, multidisciplinary approach involving the adolescents themselves is highlighted.

Human liver-derived stem cells

The search for human oval cells or bi-potential stem cells in the human liver is the subject of intensive investigation. Fetal hepatocytes (hepatoblasts) have some proliferative and bipotential capacity, but access to sufficient numbers of cells remains limiting. Candidate stem cells in the adult normal and diseased human liver have been identified using markers such as OV6, CD34, c-kit and NCAM. Lack of stem cell marker specificity however, remains a problem and further, more specific markers are required. The molecular signaling molecules and transcription factors that control proliferation and cell differentiation pathways into hepatocyte or biliary phenotype are beginning to emerge. However, whether any of the current liver stem cell approaches will be converted into effective clinical cell transplantation or gene therapy treatments has yet to be proven.

Strategies for optimizing immunosuppression in adolescent transplant recipients: a focus on liver transplantation

Adolescence is a difficult time for transplant recipients; they must learn to take responsibility for their own behavior and medication, and to balance their developing sexuality in a body that has been transformed by the adverse effects of immunosuppression. More than 80% of children survive transplantation to adolescence and adulthood, thus long-term outcome and tailoring of immunosuppression is of great importance. To date, the most experience with long-term immunosuppression regimens is cyclosporine, which is well tolerated and effective. Long-term adverse effects include hypertension, nephrotoxicity, and post-transplant lymphoproliferative disease (PTLD). The recent development of tacrolimus has improved the cosmetic adverse effects related to cyclosporine, but has similar rates of hypertension and nephrotoxicity, and possibly a higher rate of PTLD. There has been a recent, welcome development in renal sparing drugs, such as mycophenolate mofetil, which has no cosmetic adverse effects, does not require drug level monitoring and is thus particularly attractive to teenagers. Recent surveys demonstrate recovery of renal function with mycophenolate mofetil, if started prior to irreversible renal dysfunction. There are currently little published data on the use of sirolimus (rapamycin) in the pediatric population, but preliminary studies suggest that the future use of interleukin-2 receptor antibodies may be beneficial for immediate post-transplant induction of immunosuppression. It is important when planning immunosuppression for adolescents to consider the effects of drug therapy on both males and females in order to maintain fertility and to ensure safety in pregnancy. Noncompliance is a problem in this age group, but adequate practical measures and support should reduce noncompliance, and allow good, long-term graft function.

Renal function following liver transplantation for unresectable hepatoblastoma

Combination of cyclosporine (CsA) and tacrolimus immunosuppression post-liver transplantation (LT) and the chemotherapeutic drugs used to treat hepatoblastoma (HB), are nephrotoxic. We aimed to determine the severity and duration of nephrotoxicity in children following LT for unresectable HB. We reviewed all children undergoing LT for unresectable HB at the Liver Unit, Birmingham Children's Hospital, UK, from 1991 to July 2000. Thirty-six children undergoing LT for biliary atresia, matched for age and sex, were selected as controls to compare pre- and post-LT renal function. Renal function was determined by estimation of glomerular filtration rate (eGFR) derived from plasma creatinine using Schwartz's formula. Twelve children with HB (mean age of diagnosis 33 months) who underwent LT (mean age 47 months) and 36 controls (mean age of LT 34 months) were studied. CsA was the main immunosuppressive drug used in each group. The median eGFR before, and at 3, 6, 12, 24 and 36 months after LT in HB group was significantly lower than controls (93 vs. 152, 66 vs. 79, 62 vs. 86, 66 vs. 87, 64 vs. 94, 53 vs. 90 mL/min/1.73 m2, respectively; 0.01 < p < 0.03). The reductions in the median eGFR of both the HB group and controls before and at 36 months after LT were 49 and 41%, respectively. At 36 months after LT, there was a trend for partial recovery of the eGFR in the controls but not in the HB group. Children who underwent LT for unresectable HB had renal dysfunction before transplantation that persisted for 36 months after LT.