Michael R. Narkewicz

Pathogenesis and outcome of biliary atresia : current concepts

Neonatal cholestatic disorders are a group of hepatobiliary diseases occurring within the first 3 months of life. Bile flow is impaired, and patients have conjugated hyperbilirubinemia, acholic stools, and hepatomegaly. Overall, 1 in 2,500 live births is affected with a neonatal cholestatic disorder (1). The two most common causes of neonatal cholestasis are biliary atresia and idiopathic neonatal hepatitis, accounting for up to 50% to 70% of cases. Other causes include a variety of neonatal infections (viral, toxoplasmosis, syphilis, bacterial), metabolic and genetic diseases, progressive familial intrahepatic cholestatic disorders (PFIC), paucity of interlobular bile duct disorders (e.g., Alagille syndrome), choledochal cyst, ischemia–reperfusion injury, association with parenteral nutrition administration, and other conditions (Table 1). Despite clinical improvement after the portoenterostomy procedure, approximately 70% to 80% of children with biliary atresia will eventually require liver transplantation; thus, biliary atresia alone accounts for almost 50% of all liver transplants performed in children (1). It should be noted that

Oxidant injury to hepatic mitochondria in patients with Wilson's disease and Bedlington terriers with copper toxicosis

77 million is spent each year in the United States on liver transplantation for children and the ensuing hospitalizations (2). This sum of money covers 0.2% of total health care expenditures related to children, even though these children represent 0.0006% of the total pediatric population. Importantly, this disproportionate expenditure for liver transplantation in children could be cut in half if improved therapies for biliary atresia were developed that could abrogate or further delay the need for liver transplantation. Remarkably, little is known about the etiopathogenesis of biliary atresia; consequently, there has been slow progress in developing improved therapies or preventative strategies during the past decade. The purpose of this review is to summarize recent advances in the diagnosis and management of biliary atresia, examine the clinical outcome, describe the evolving theories of the etiology and pathogenesis of this disorder, and highlight gaps in our current knowledge.

Studies of Pediatric Liver Transplantation (SPLIT) : Year 2000 outcomes

BACKGROUND/AIMS Copper overload leads to liver injury in humans with Wilsons disease and in Bedlington terriers with copper toxicosis; however, the mechanisms of liver injury are poorly understood. This study was undertaken to determine if oxidant (free radical) damage to hepatic mitochondria is involved in naturally occurring copper toxicosis. METHODS Fresh liver samples were obtained at the time of liver transplantation from 3 patients with Wilsons disease, 8 with cholestatic liver disease, and 5 with noncholestatic liver disease and from 8 control livers. Fresh liver was also obtained by open liver biopsy from 4 copper-overloaded and 4 normal Bedlington terriers and from 8 control dogs. Hepatic mitochondria and microsomes (humans only) were isolated, and lipid peroxidation was measured by lipid-conjugated dienes and thiobarbituric acid-reacting substances. In humans, liver alpha-tocopherol content was measured. RESULTS Lipid peroxidation and copper content were significantly increased (P < 0.05) in mitochondria from patients with Wilsons disease and copper-overloaded Bedlington terriers. More modest increases in lipid peroxidation were present in microsomes from patients with Wilsons disease. Mitochondrial copper concentrations correlated strongly with the severity of mitochondrial lipid peroxidation. Hepatic alpha-tocopherol content was decreased significantly in Wilsons disease liver. CONCLUSIONS These data suggest that the hepatic mitochondrion is an important target in hepatic copper toxicity and that oxidant damage to the liver may be involved in the pathogenesis of copper-induced injury.

Pathology of chronic hepatitis C in children: Liver biopsy findings in the Peds‐C Trial

Background. Initiated in 1995, the Studies of Pediatric Liver Transplantation (SPLIT) registry database is a cooperative research network of pediatric transplantation centers in the United States and Canada. The primary objectives are to characterize and follow trends in transplant indications, transplantation techniques, and outcomes (e.g., patient/graft survival, rejection, growth parameters, and immunosuppressive therapy.) Methods. As of June 15, 2000, 29 centers registered 1144 patients, 640 of whom received their first liver-only transplant while registered in SPLIT. Patients are followed every 6 months for 2 years and yearly thereafter. Data are submitted to a central coordinating center. Results. One/two-year patient survival and graft loss estimates are 0.85/0.82 and 0.77/0.72, respectively. Risk factors for death include: in ICU at transplant (relative risk (RR)=2.63, P <0.05) and height/weight deficits of two or more standard deviations (RR=1.67, P <0.05). Risk factors for graft loss include: in ICU at transplant (RR=1.77, P <0.05) and receiving a cadaveric split organ compared with a whole organ (RR=2.3, P <0.05). The percentage of patients diagnosed with hepatic a. and portal v. thrombosis were 9.7% and 7%, respectively; 15% had biliary complications within 30 days. At least one re-operation was required in 45%. One/two-year rejection probability estimates are 0.60/0.66. Tacrolimus, as primary therapy posttransplant, reduces first rejection risk (RR=0.70, P <0.05). Eighty-nine percent of school-aged children are in school full-time, 18 months posttransplant. Conclusions. This report provides one of the first descriptions of characteristics and clinical courses of a multicenter pediatric transplant population. Observations are subject to patient selection biases but are useful for generating hypothesis for future studies.

Outcome of syndromic paucity of interlobular bile ducts (Alagille syndrome) with onset of cholestasis in infancy

There is relatively little information in the literature on the histopathology of chronic hepatitis C in children. The Peds‐C Trial, designed to test the efficacy and safety of peginterferon alfa‐2a and ribavirin in children, provided an opportunity to examine liver biopsies from 121 treatment‐naïve children, ages 2 to 16 (mean, 9.8 years) infected with the hepatitis C virus (HCV) and with no other identifiable cause for liver disease, signs of hepatic decompensation, or another significant nonhepatic disease. Liver biopsies were scored for inflammation, fibrosis, steatosis, and other histological features. Inflammation in the biopsy was minimal in 42%, mild in 17%, moderate in 38%, and severe in only 3%. Five had bridging fibrosis, and 2 had cirrhosis. Steatosis was absent in 56%, minimal in 34%, and mild in 10%. Inflammation scores correlated with fibrosis scores, serum alanine aminotransferase levels, and duration of infection, but not with age, body mass index z score, or HCV genotype. Fibrosis scores correlated with inflammation but not with age, HCV genotype, body mass index z score, or steatosis parameters. Steatosis correlated with serum alanine aminotransferase levels and body mass index z scores; overweight children had more fibrosis than the non‐overweight. In conclusion, in this cohort of HCV‐infected children, inflammation, fibrosis, and steatosis were milder than reported for treatment‐naïve adults with chronic hepatitis C, but there were several with bridging fibrosis or cirrhosis. The positive correlation of inflammation with duration of infection and fibrosis and of obesity with fibrosis suggest that children with chronic hepatitis C will be at risk for progressive liver disease as they age and possibly acquire other comorbid risk factors. (HEPATOLOGY 2007.)

Multicenter trial of d-α-tocopheryl polyethylene glycol 1000 succinate for treatment of vitamin E deficiency in children with chronic cholestasis

OBJECTIVE To determine the outcome, in index patients followed at an American Center, of syndromic paucity of interlobular bile ducts (sPILBD; Alagille syndrome), with onset of cholestasis in infancy. DESIGN Cohort. SETTING Regional referral center for infants and children with liver disease. RESULTS During the past 10 years, 26 unrelated children with sPILBD were identified. Fifteen (58%) are alive without liver transplantation at a median age of 12.1 years. Three (11%) died, all before 2 years of age. Eight patients (31%) underwent liver transplantation at a median age of 6.5 years; all eight are alive a median 5.4 years after transplantation. The most common factors contributing to the decision for transplantation were bone fractures, pruritus, and severe xanthoma. The predicted probability of reaching 19 years of age without transplantation is about 50%; however, with transplantation, the predicted probability of long-term survival is 87%. Of 26 patients 4 (15%) have had significant central nervous system disease, and two of them have died of intracranial hemorrhage. Of the four patients who underwent cholecystoportostomy or portoenterostomy, three required liver transplantation. CONCLUSIONS Children with sPILBD identified in infancy because of cholestasis have a 50% probability of long-term survival without liver transplantation, a worse prognosis than other follow-up studies have reported. In selected patients, liver transplantation provides the opportunity for long-term survival with improved quality of life. Patients with sPILBD are at risk of having intracranial hemorrhage.

NASPGHAN Practice Guidelines: Diagnosis and Management of Hepatitis C Infection in Infants, Children, and Adolescents

BACKGROUND Malabsorption and deficiency of vitamin E causing neurological degeneration are common consequences of chronic childhood cholestatic liver disease. The objective of this study was to determine the long-term efficacy and safety of d-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS) in correcting vitamin E deficiency in children with chronic cholestasis who were unresponsive to other forms of oral vitamin E. METHODS Sixty vitamin E-deficient children with chronic cholestasis unresponsive to 70-212 IU.kg-1.day-1 of oral vitamin E were entered into a trial at eight centers in the United States. After initial evaluation, treatment was started with 25 IU.kg-1.day-1 of TPGS. Vitamin E status, neurological function quantitated by a specific scoring system, and clinical and biochemical parameters were monitored during therapy. RESULTS All children responded to TPGS with normalization of vitamin E status. Neurological function, which had deteriorated before entry in the trial, improved in 25 patients, stabilized in 27, and worsened in only 2 after a mean of 2.5 years of therapy. No adverse effects were observed. CONCLUSIONS TPGS (20-25 IU.kg-1.day-1) appears to be a safe and effective form of vitamin E for reversing or preventing vitamin E deficiency during chronic childhood cholestasis.

The combination of ribavirin and peginterferon is superior to peginterferon and placebo for children and adolescents with chronic hepatitis C

Hepatitis C virus (HCV) is an RNA virus that affects >180 million individuals worldwide with a high propensity for chronic infection. Children with HCV infection differ from adults in several ways including some modes of transmission, rates of clearance, progression of fibrosis, and the duration of potential chronic infection when acquired at birth. Since the discovery of HCV in 1989, there have been significant advances in the understanding of the virology and natural history of chronic HCV infection in children. In addition, there are now several treatment options for children with chronic hepatitis C infection and many new therapies on the horizon. As a consequence, the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition brought together experts in pediatric hepatology to review the available data in children and provide clinicians with approaches to the diagnosis, management, and prevention of HCV infection in children and adolescents. The guideline details the epidemiology and natural history of HCV infection in children, the diagnostic workup, monitoring and treatment of disease, and provides an update on future treatment options and areas of research.

Treatment of children with chronic hepatitis B virus infection in the United States: Patient selection and therapeutic options

BACKGROUND & AIMS Although randomized trials of adults infected with hepatitis C virus (HCV) have shown that ribavirin increases the efficacy of pegylated interferon (PEG), such trials have not been performed in children. We conducted a randomized controlled trial of PEG and ribavirin, compared with PEG and placebo, in children 5 to 17 years old with chronic hepatitis C. METHODS HCV RNA-positive children from 11 university medical centers were randomly assigned to receive either PEG alfa-2a (PEG-2a; 180 μg/1.73 m(2) body surface area, subcutaneously each week; n = 55) and ribavirin (15 mg/kg orally in 2 doses daily) or PEG-2a and placebo (n = 59) for 48 weeks. The primary end point was sustained virologic response (SVR; lack of detectable HCV RNA at least 24 weeks after stopping therapy). RESULTS SVR was achieved in 53% of children treated with PEG-2a and ribavirin, compared with 21% of children who received PEG-2a and placebo (P < .001). Early virologic response (HCV RNA reduction >2 log(10) IU at 12 weeks) had a negative predictive value of only 0.89 in children with genotype 1, indicating that these children might benefit from 24 weeks of therapy before stopping treatment. Side effects, especially neutropenia, led to dose modification in 40% of children. Eighty-two percent of the PEG/ribavirin and 86% of the PEG/placebo group were in compliance with the year 2 follow-up visit; the durability of virologic response was 100% in both groups. CONCLUSIONS The combination of PEG and ribavirin is superior to PEG and placebo as therapy for chronic hepatitis C in children and adolescents.

Improvement of cyclosporin absorption in children after liver transplantation by means of water-soluble vitamin E

Chronic hepatitis B virus (HBV) infection in children presents a therapeutic challenge for the practitioner. Decisions regarding selection of patients who may benefit from treatment, appropriate timing of treatment, and the choice of antiviral therapy are complex and are compounded by the limited number of drugs that have been studied in children. An expert panel of nationally recognized pediatric liver specialists was convened by the Hepatitis B Foundation on August 11, 2009, to consider clinical practice relative to the therapeutic options available for children. A detailed account of these discussions is provided, and the opinions expressed are based on consensus of the experts, as well as on published evidence when available. The panel concludes that, at this time, there is no established benefit of treatment of children in the immune tolerant phase, and there is a very high risk of development of drug resistance. In addition, there is no indication for treatment of children in the inactive carrier state. For children in the immune active or reactivation phases, liver histology can help guide treatment decisions, and family history of liver disease, especially hepatocellular carcinoma, may argue for early treatment in some cases. Outside of clinical trials, interferon is the agent of choice in most cases. Nucleos(t)ide analogues are secondary therapies, and children who receive these agents require careful monitoring for development of resistance. There are a few situations when treatment is indicated regardless of HBV DNA or alanine aminotransferase levels. There is still much to be elucidated about the appropriate use of HBV therapy in children. Until more clinical data and therapeutic options are available, a conservative approach is warranted. (HEPATOLOGY 2010.)