Risk of variceal hemorrhage and pretransplant mortality in children with biliary atresia

BACKGROUND AND AIMS

The natural history of gastroesophageal variceal hemorrhage (VH) in biliary atresia (BA) is not well characterized. We analyzed risk factors, incidence, and outcomes of VH in a longitudinal multicenter study.

APPROACH AND RESULTS

Participants enrolled in either an incident (Prospective Database of Infants with Cholestasis [PROBE]) or prevalent (Biliary Atresia Study of Infants and Children [BASIC]) cohort of BA were included. Variceal hemorrhage (VH) was defined based on gastrointestinal bleeding in the presence of varices accompanied by endoscopic or nontransplant surgical intervention. Cumulative incidence of VH and transplant-free survival was compared based on features of portal hypertension (e.g., splenomegaly, thrombocytopenia) and clinical parameters at baseline in each cohort (PROBE: 1.5 to 4.5 months after hepatoportoenterostomy [HPE]; BASIC: at enrollment > 3 years of age). Analyses were conducted on 869 children with BA enrolled between June 2004 and December 2020 (521 in PROBE [262 (51%) with a functioning HPE] and 348 in BASIC). The overall incidence of first observed VH at 5 years was 9.4% (95% CI: 7.0-12.4) in PROBE and 8.0% (5.2-11.5) in BASIC. Features of portal hypertension, platelet count, total bilirubin, aspartate aminotransferase (AST), albumin, and AST-to-platelet ratio index at baseline were associated with an increased risk of subsequent VH in both cohorts. Transplant-free survival at 5 years was 45.1% (40.5-49.6) in PROBE and 79.2% (74.1-83.4) in BASIC. Two (2.5%) of 80 participants who had VH died, whereas 10 (12.5%) underwent transplant within 6 weeks of VH.

CONCLUSIONS

The low risk of VH and associated mortality in children with BA needs to be considered in decisions related to screening for varices and primary prophylaxis of VH.

Consensus expert recommendations for the diagnosis and management of autosomal recessive polycystic kidney disease: report of an international conference

Autosomal recessive polycystic kidney disease (ARPKD; MIM 263200) is a severe, typically early onset form of cystic disease that primarily involves the kidneys and biliary tract. Phenotypic expression and age at presentation can be quite variable. The incidence of ARPKD is 1 in 20,000 live births, and its pleotropic manifestations are potentially life-threatening. Optimal care requires proper surveillance to limit morbidity and mortality, knowledgeable approaches to diagnosis and treatment, and informed strategies to optimize quality of life. Clinical management therefore is ideally directed by multidisciplinary care teams consisting of perinatologists, neonatologists, nephrologists, hepatologists, geneticists, and behavioral specialists to coordinate patient care from the perinatal period to adulthood. In May 2013, an international team of 25 multidisciplinary specialists from the US, Canada, Germany, and the United Kingdom convened in Washington, DC, to review the literature published from 1990 to 2013 and to develop recommendations for diagnosis, surveillance, and clinical management. Identification of the gene PKHD1, and the significant advances in perinatal care, imaging, medical management, and behavioral therapies over the past decade, provide the foundational elements to define diagnostic criteria and establish clinical management guidelines as the first steps towards standardizing the clinical care for ARPKD patients. The key issues discussed included recommendations regarding perinatal interventions, diagnostic criteria, genetic testing, management of renal and biliary-associated morbidities, and behavioral assessment. The meeting was funded by the National Institutes of Health and an educational grant from the Polycystic Kidney Disease Foundation. Here we summarize the discussions and provide an updated set of diagnostic, surveillance, and management recommendations for optimizing the pediatric care of patients with ARPKD. Specialist care of ARPKD-related complications including dialysis, transplantation, and management of severe portal hypertension will be addressed in a subsequent report. Given the paucity of information regarding targeted therapies in ARPKD, this topic was not addressed in this conference.”

Liver transplantation for pediatric metabolic disease

Liver transplantation (LTx) was initially developed as a therapy for liver diseases known to be associated with a high risk of near-term mortality but is based upon a different set of paradigms for inborn metabolic diseases. As overall outcomes for the procedure have improved, LTx has evolved into an attractive approach for a growing number of metabolic diseases in a variety of clinical situations. No longer simply life-saving, the procedure can lead to a better quality of life even if not all symptoms of the primary disorder are eliminated. Juggling the risk-benefit ratio thus has become more complicated as the list of potential disorders amenable to treatment with LTx has increased. This review summarizes presentations from a recent conference on metabolic liver transplantation held at the Children's Hospital of Pittsburgh of UPMC on the role of liver or hepatocyte transplantation in the treatment of metabolic liver disease.

Liver transplantation for classical maple syrup urine disease: long-term follow-up in 37 patients and comparative United Network for Organ Sharing experience

OBJECTIVE

To assess clinical and neurocognitive function in children who have undergone liver transplantation for classical maple syrup urine disease (MSUD).

STUDY DESIGN

A total of 35 patients with classical MSUD (age 9.9 ± 7.9 years) underwent liver transplantation between 2004 and 2009. Six patients donated their liver to recipients without MSUD ("domino" transplant). We analyzed clinical outcomes for our cohort and 17 additional cases from the national United Network for Organ Sharing registry; 33 patients completed IQ and adaptive testing before transplantation, and 14 completed testing 1 year later.

RESULTS

Patient and graft survival were 100% at 4.5 ± 2.2 years of follow-up. Liver function was normal in all patients. Branched-chain amino acid levels were corrected within hours after surgery and remained stable, with leucine tolerance increasing more than 10-fold. All domino transplant recipients were alive and well with normal branched-chain amino acid homeostasis at the time of this report. Patient and graft survival for all 54 patients with MSUD undergoing liver transplantation in the United States during this period were 98% and 96%, respectively. One-third of our patients were mentally impaired (IQ ≤ 70) before transplantation, with no statistically significant change 1 year later.

CONCLUSION

Liver transplantation is an effective long-term treatment for classical MSUD and may arrest brain damage, but will not reverse it.

Increased expression of peripheral blood leukocyte genes implicate CD14+ tissue macrophages in cellular intestine allograft rejection

Recurrent rejection shortens graft survival after intestinal transplantation (ITx) in children, most of whom also experience early acute cellular rejection (rejectors). To elucidate mechanisms common to early and recurrent rejection, we used a test cohort of 20 recipients to test the hypothesis that candidate peripheral blood leukocyte genes that trigger rejection episodes would be evident late after ITx during quiescent periods in genome-wide gene expression analysis and would achieve quantitative real-time PCR replication pre-ITx (another quiescent period) and in the early post-ITx period during first rejection episodes. Eight genes were significantly up-regulated among rejectors in the late post-ITx and pre-ITx periods, compared with nonrejectors: TBX21, CCL5, GNLY, SLAMF7, TGFBR3, NKG7, SYNE1, and GK5. Only CCL5 was also up-regulated in the early post-ITx period. Among resting peripheral blood leukocyte subsets in randomly sampled nonrejectors, CD14(+) monocytes expressed the CCL5 protein maximally. Compared with nonrejectors, rejectors demonstrated higher counts of both circulating CCL5(+)CD14(+) monocytes and intragraft CD14(+) monocyte-derived macrophages in immunohistochemistry of postperfusion and early post-ITx biopsies from the test and an independent replication cohort. Donor-specific alloreactivity measured with CD154(+) T-cytotoxic memory cells correlated with the CCL5 gene and intragraft CD14(+) monocyte-derived macrophages at graft reperfusion and early post-ITx. CCL5 gene up-regulation and CD14(+) macrophages likely prime cellular ITx rejection. Infiltration of reperfused intestine allografts with CD14(+) macrophages may predict rejection events.

Differences in presentation and progression between severe FIC1 and BSEP deficiencies

BACKGROUND & AIMS

Progressive familial intrahepatic cholestasis (PFIC) with normal serum levels of gamma-glutamyltranspeptidase can result from mutations in ATP8B1 (encoding familial intrahepatic cholestasis 1 [FIC1]) or ABCB11 (encoding bile salt export pump [BSEP]). We evaluated clinical and laboratory features of disease in patients diagnosed with PFIC, who carried mutations in ATP8B1 (FIC1 deficiency) or ABCB11 (BSEP deficiency). Our goal was to identify features that distinguish presentation and course of these two disorders, thus facilitating diagnosis and elucidating the differing consequences of ATP8B1 and ABCB11 mutations.

METHODS

A retrospective multi-center study was conducted, using questionnaires and chart review. Available clinical and biochemical data from 145 PFIC patients with mutations in either ATP8B1 (61 "FIC1 patients") or ABCB11 (84 "BSEP patients") were evaluated.

RESULTS

At presentation, serum aminotransferase and bile salt levels were higher in BSEP patients; serum alkaline phosphatase values were higher, and serum albumin values were lower, in FIC1 patients. Elevated white blood cell counts, and giant or multinucleate cells at liver biopsy, were more common in BSEP patients. BSEP patients more often had gallstones and portal hypertension. Diarrhea, pancreatic disease, rickets, pneumonia, abnormal sweat tests, hearing impairment, and poor growth were more common in FIC1 patients. Among BSEP patients, the course of disease was less rapidly progressive in patients bearing the D482G mutation.

CONCLUSIONS

Severe forms of FIC1 and BSEP deficiency differed. BSEP patients manifested more severe hepatobiliary disease, while FIC1 patients showed greater evidence of extrahepatic disease.

The changing face of post-transplant lymphoproliferative disease in the era of molecular EBV monitoring

Pediatric PTLD is often associated with primary EBV infection and immunosuppression. The aim was to retrospectively review the spectrum of histologically documented PTLD for two time intervals differentiated by changes in use of molecular EBV monitoring. Eleven of 146 patients (7.5%) in 2001-2005 (Era A) and 10 of 92 (10.9%) in 1993-1997 (Era B) were diagnosed with PTLD. The median age at liver transplantation (0.8 and 0.9 yr, respectively) and the median duration between liver transplant and diagnosis of PTLD (0.6 and 0.7 yr, respectively) were similar in both eras. However, patients in Era A presented with significantly less advanced histological disease compared to patients in Era B (p=0.03). Specifically, nine patients (82%) in Era A had Pl hyperplasia/polymorphic PTLD, whereas in Era B, six had advanced histological disease (five monomorphic and one unclassified). Three transplant recipients in Era B died secondary to PTLD, whereas there were no PTLD-related deaths in Era A (p=0.03). Heightened awareness of risk for PTLD, alterations in baseline immunosuppression regimens, implementation of molecular EBV monitoring, pre-emptive reduction in immunosuppression and improved therapeutic options may have all contributed to a milder PTLD phenotype and improved clinical outcomes.

Mathematical optimization to improve cows' artificial insemination services

Engineering tools and mathematical optimization are applied in this study to plan the work of the agents of the cow artificial insemination service (inseminator) in Israel. Time is crucial in insemination as the chances of conception decline with increasing delay between the start of estrus and insemination. About 1,090 artificial inseminations of cows are performed daily in Israel. They involve 412 farms in 283 villages, and are performed by 29 inseminators; the work plan should balance the work load among the inseminators. To this end, the working time of an inseminator in each village is required. Thus, a model to predict the working time in a village was developed. Subsequently, a mathematical optimization model was designed and solved, which aims to allocate customers to trips and to determine the itinerary of each trip to minimize total distance/time. The main benefits included a 21.4% reduction in total traveling time and a 55% reduction in the difference between the lengths of the longest and shortest working days. Moreover, the longest delay in reaching an estrous cow is reduced from 7.6 to 5.9 h (i.e., by 1.7 h), which may increase the conception ratio by some 7%. In addition, the trade-off between work balance and total traveling time was studied.

A retrospective single-center review of primary sclerosing cholangitis in children

BACKGROUND & AIMS

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease characterized by inflammation and progressive bile duct fibrosis. There are limited data on pediatric PSC.

METHODS

We performed a retrospective chart review of 47 pediatric patients with PSC.

RESULTS

The mean age at diagnosis was 11 +/- 4.9 years. Symptoms occurred before presentation in 81% of patients; inflammatory bowel disease was found in 59% and autoimmune hepatitis (overlap syndrome) in 25% of patients. Magnetic resonance cholangiography revealed both extrahepatic and intrahepatic, isolated intrahepatic, isolated extrahepatic, and no biliary involvement (small-duct PSC) in 40%, 14%, 10%, and 36%, respectively. Advanced fibrosis (stage >II) was present in 65%. Colonoscopy revealed pancolitis, rectal sparing, and normal findings in 24%, 24%, and 18%, respectively. All patients were treated with ursodeoxycholic acid (UDCA); 9 with overlap syndrome also received immunosuppressants. Fifteen patients without overlap syndrome had positive autoimmune markers and responded to UDCA monotherapy. Liver transplantation was performed in 9 patients (3 with overlap syndrome and 2 with small-duct PSC) at a median time of 7 years after diagnosis. The 10-year posttransplant survival rate was 89%.

CONCLUSIONS

In one of the largest single-center studies of children with PSC, we found that most children with PSC had inflammatory bowel disease or autoimmune overlap and advanced fibrosis at diagnosis. Levels of alanine aminotransferase and gamma-glutamyl transferase were highest in patients with overlap syndrome and lowest in those with small-duct PSC. Levels of serum liver enzymes normalized after therapy with UDCA, including patients with positive autoimmune markers without histologic features of autoimmune hepatitis.

Adherence and medical outcomes in pediatric liver transplant recipients who transition to adult services

Non-adherence to medications is associated with poor medical outcomes in adolescent transplant recipients. It is unclear whether non-adherence is further compromised when transplant recipients transition to the adult health care system. The purpose of the present study was to examine whether adherence changes during transition. We reviewed the medical records of 14 recently transitioned patients and compared their adherence and corresponding medical outcomes before and after transition. These outcomes were also compared with two cohorts of patients receiving care solely in pediatric or adult services. Medication adherence, measured through the use of standard deviations of tacrolimus blood levels, was examined for all patients. We found that adherence to tacrolimus significantly decreased after transition. After transitioning, patients furthermore exhibited poorer adherence than patients in the other two cohorts did over time. This small retrospective study suggests that the period of transition from pediatric to adult transplant clinics is a vulnerable one. Larger, prospective investigations of the transition process are necessary before recommendations are made regarding interventions.

Surgical guidelines for the management of extra-hepatic portal vein obstruction

The recent introduction of the meso Rex bypass raises a possible paradigm shift in the therapeutic approach to extra-hepatic portal vein obstruction (EHPVO). Long-term follow-up of patients with EHPVO has revealed a variety of complications including variceal hemorrhage, hypersplenism, biliopathy, growth/development retardation and neuropsychiatric disease. The meso Rex bypass restores physiologic blood flow to the liver. Thus, when feasible, the meso Rex bypass should be considered in patients with clinically significant manifestations of EHPVO. The opinions of a panel of experts regarding the surgical approach to the management of EHPVO are presented.

Expert pediatric opinion on the Report of the Baveno IV consensus workshop on methodology of diagnosis and therapy in portal hypertension

Portal hypertension leads to a wide variety of complications, which lead to significant morbidity and mortality and are some of the leading reasons for liver transplantation in children with chronic liver disease. Evidence-based approaches to the management of adults with portal hypertension exist and have been comprehensively reviewed in a series of international meetings, including the Baveno meetings. Similar evidence-based approaches for the management of portal hypertension in children do not exist and as such international meetings on portal hypertension have not focused on this problem in children. On October 7, 2005 at The Mount Sinai School of Medicine, a panel of pediatric experts reviewed the most recent Baveno statement and crafted a statement modified with their opinions vis a vis approaches to the management of portal hypertension in children.

Prospective analysis of nonadherence in autoimmune hepatitis: a common problem

OBJECTIVES

To prospectively assess nonadherence to medications, the relationship between nonadherence and medical outcome and the relationship between a psychiatric risk factor (posttraumatic stress) and nonadherence in patients with a diagnosis of autoimmune hepatitis.

PATIENTS AND METHODS

Data were obtained in children with autoimmune hepatitis, who had consented to prospective monitoring of adherence, during 1 year of follow-up in our pediatric liver program. An electronic monitoring device as well as posttransplant trough blood levels of tacrolimus was used to evaluate adherence. A validated self-report questionnaire was used to assess posttraumatic stress. The medical outcome measure was the maximal alanine transaminase (ALT) for each monitored patient.

RESULTS

Of 37 pediatric patients, 34 (15 posttransplant) enrolled. Fourteen (41%) used the monitoring device as directed. Monitor readings ranged between 28% and 94% of optimal adherence (100%). No patient took the medications exactly as prescribed. Electronic monitoring device readings correlated inversely with maximal ALT (P = 0.03, r = -0.59), and were also correlated with the tacrolimus level variability as a measure of adherence (P = 0.04, r = -0.72). Posttraumatic stress disorder questionnaire scores were correlated with both measures of adherence (for electronic monitoring, P = 0.02, r = -0.70, for tacrolimus levels, P = 0.03, r = 0.62).

CONCLUSIONS

Nonadherence to immunosuppressants was common in this cohort, and it correlated with higher maximal ALT. Nonadherence is therefore an important risk factor for poor outcome in patients with autoimmune hepatitis. Posttraumatic stress symptoms, which were correlated with nonadherence, may serve as a focus for adherence-improving interventions.

Bullous pemphigoid after liver transplantation for liver failure

Coomb's positive autoimmune hemolytic anemia with giant cell hepatitis (GCH) is a rare cause of liver failure and is usually associated with poor prognosis. A child with liver kidney microsomal (LKM) antibody positivity underwent successful liver transplantation for liver failure secondary to GCH with Coomb's positive hemolytic anemia. Autoimmune neutropenia developed ten months after transplant. Four months later, pemphigoid skin lesions developed. The diagnosis of bullous pemphigoid (BP) was made on the basis of skin biopsy, direct and indirect immunofluorescence test results. Treatment was with immunosuppressants - prednisone and azathioprine/rapamycin, with addition of dapsone when lesions persisted. This child is unique in that his liver function and hemolytic anemia appeared to normalize after liver transplant, but neutropenia and BP both thought to be autoimmune in etiology, developed more than a year post-transplant.

Hypercholesterolemia and changes in lipid and bile acid metabolism in male and female cyp7A1-deficient mice

Cholesterol 7alpha-hydroxylase, a rate-limiting enzyme for bile acid synthesis, has been implicated in genetic susceptibility to atherosclerosis. The gene, CYP7A1, encoding a protein with this activity, is expressed normally only in hepatocytes and is highly regulated. Our cyp7A1 gene knockout mouse colony, as young adults on a chow diet, is hypercholesterolemic. These mice were characterized extensively to understand how cyp7A1 affects lipid and bile acid homeostasis in different tissue compartments and whether gender plays a modifying role. Both male and female cyp7A1-deficient mice had decreased hepatic LDL receptors, unchanged hepatic cholesterol synthesis, increased intestinal cholesterol synthesis and bile acid transporters, and decreased fecal bile acids but increased fecal sterols. In females, cyp7A1 deficiency also caused changes in hepatic fatty acid metabolism, decreased hepatic canalicular bile acid transporter, Bsep, and gallbladder bile composition altered to a lithogenic profile. Taken together, the data suggest that cyp7A1 deficiency results in a proatherogenic phenotype in both genders and leads to a prolithogenic phenotype in females.

Improvement of hepatopulmonary syndrome after transjugular intrahepatic portasystemic shunting: case report and review of literature

The hepatopulmonary syndrome has been described in as many as 5-29% of patients with liver disease. Patients with this syndrome may suffer from chronic hypoxemia, and mortality rates of liver patients with this syndrome are as high as 41%. Early diagnosis of such patients is essential. Currently, liver transplantation is the only effective therapy for such patients, and reversal of this syndrome is seen in up to 80% of patients post-transplant. Transjugular intrahepatic portasystemic shunting (TIPS) as a therapeutic maneuver for this syndrome has been described in five patients to date with mixed results. Reduction in portal hypertension with consequent redistribution of blood flow and altered synthesis of vasodilatory chemicals have been postulated to help resolve this disease. In this report, we describe an 11-yr-old female with biliary atresia and hepatopulmonary syndrome. Her disease was complicated with recurrent variceal bleeding. TIPS achieved a therapeutic response of both her bleeding and respiratory complications.

Inflammatory-mediated repression of the rat ileal sodium-dependent bile acid transporter by c-fos nuclear translocation

BACKGROUND & AIMS

Ileal malabsorption of bile salts is observed in Crohn's ileitis. We define the transcriptional mechanisms involved in cytokine-mediated repression of the rat apical sodium-dependent bile acid transporter (ASBT).

METHODS

ASBT regulation was studied in IL-1beta-treated IEC-6 and Caco-2 cells and in indomethacin-treated rats.

RESULTS

Indomethacin-induced ileitis in Lewis rats leads to specific reductions in ileal ASBT messenger RNA and protein levels, whereas c-jun and c-fos are induced. The proinflammatory cytokines interleukin-1beta and tumor necrosis factor repress the activity of the ASBT promoter in Caco-2 and intestinal epithelial cell-6 cells. This effect is blocked by the proteasome inhibitor, MG-132, or by the phosphatidyl inositol 3-kinase inhibitor, wortmannin. Indomethacin (in vivo) or proinflammatory cytokine (in vitro) treatment leads to serine phosphorylation and nuclear translocation of c-fos. Mutation of a 5' activated protein (AP)-1 site inactivates the ASBT promoter, whereas mutation of the 3' site abrogates the proinflammatory cytokine-mediated repression. The 5' site binds a c-jun homodimer, whereas the 3' site binds a c-jun/c-fos heterodimer. c-Jun overexpression enhances ASBT promoter activity, whereas a dominant negative c-jun construct inactivates the promoter. c-Fos overexpression represses promoter activity. A 27 base pair cis-element from the 3' site in the ASBT promoter imparts cytokine-mediated down-regulation to a heterologous SV40 promoter construct.

CONCLUSIONS

The ASBT promoter contains 2 distinct cis AP-1 elements; the 5' element binds homodimeric c-jun and mediates basal transcription. Inflammation is associated with up-regulation, phosphorylation, and nuclear translocation of c-fos, which then represses ASBT promoter activity via binding of the 3' AP-1 element by a c-fos/c-jun heterodimer.

Genetic induction of proinflammatory immunity in children with biliary atresia

BACKGROUND

Biliary atresia is the commonest cause of pathological jaundice in infants and the leading indication for liver transplantation in children worldwide. The cause and pathogenesis remain largely unknown. Because of clinical heterogeneity and experimental difficulties in addressing molecular mechanisms underlying multifactorial disorders in human beings, we searched for genomic signatures of biliary atresia in affected infants.

METHODS

We generated pools of biotinylated cRNA from livers of 14 infants with biliary atresia and six with neonatal intrahepatic cholestasis (diseased controls) and hybridised the cRNA against oligonucleotide-based gene chips. Immunohistochemistry and reverse transcriptase (RT)-PCR were used to assess the specificity of the findings and functional commitment of lymphocytes in affected livers.

FINDINGS

Data filtering, to identify genes that are differentially expressed, and cluster analysis revealed a predominant and coordinated activation of immunity/inflammation genes within the livers of infants with biliary atresia. Most of the genes showed differential lymphocyte function, with activation of osteopontin, a regulator of cell-mediated (T-helper 1 [Th-1]) immunity in T-helper lymphocytes, and suppression of immunoglobulin genes in early stages of disease. These findings were associated with production of interferon gamma in 65% of infants with biliary atresia and no diseased control. However, histologically similar inflammatory infiltrates were present in livers of both groups, implying differential activation states of similar cell types.

INTERPRETATION

Livers of infants with biliary atresia have a coordinated activation of genes involved in lymphocyte differentiation. Among these genes, the overexpression of osteopontin and interferon gamma points to a potential role of Th-1-like cytokines in disease pathogenesis.

A novel intronic mutation results in the use of a cryptic splice acceptor site within the coding region of UGT1A1, causing Crigler-Najjar syndrome type 1

Crigler-Najjar syndrome type 1 (CN-1) is characterized by severe unconjugated hyperbilirubinemia due to an inherited deficiency of hepatic bilirubin uridinediphosphoglucuronate glucuronosyltransferase (UGT1A1), inherited as an autosomal recessive characteristic. CN-1 is potentially lethal because of the risk of bilirubin encephalopathy (kernicterus). Genetic lesions of the coding region of the UGT1A1 gene are known to cause CN-1. Here, we report a CN-1 patient who has a novel G > A mutation at the splice acceptor site in intron 4 (IVS4-1 G > A) on one allele, and a T > A substitution followed by a 13-nt deletion in exon 2 (877T > A 878-890del) of the other allele. As the UGT1A1 gene is expressed specifically in the liver, structural analysis of the expressed UGT1A1 mRNA requires liver biopsy. To use a noninvasive approach to determine the effect of the splice site mutation on splicing of the RNA transcript, we amplified the relevant region of the genomic DNA by long-range polymerase chain reaction (PCR). The amplicon was cloned in an expression plasmid and transfected into COS-7 cells. The expressed mRNA was amplified by reverse-transcription-primed PCR. Nucleotide sequence determination of the amplicon showed that the splice acceptor site mutation caused splicing of the 3'-end of exon 4 to a cryptic splice site within exon 5. This resulted in deletion of the first 7 nucleotides of exon 5, causing a frameshift and premature truncation of UGT1A1, with consequent inactivation of the enzyme.

The role of AP-1 in the transcriptional regulation of the rat apical sodium-dependent bile acid transporter

Ileal reclamation of bile salts, a critical determinant of their enterohepatic circulation, is mediated primarily by the apical sodium-dependent bile acid transporter (ASBT=SLC10A2). We have defined mechanisms involved in the transcriptional regulation of ASBT. The ASBT gene extends over 17 kilobases and contains five introns. Primer extension analysis localized two transcription initiation sites 323 and 255 base pairs upstream of the initiator methionine. Strong promoter activity is imparted by both a 2.7- and 0.2-kilobase 5'-flanking region of ASBT. The promoter activity is cell line specific (Caco-2, not Hep-G2, HeLa-S3, or Madin-Darby canine kidney cells). Four distinct specific binding proteins were identified by gel shift and cross-linking studies using Caco-2 or rat ileal nuclear extracts. Two AP-1 consensus sites were identified in the proximal promoter. DNA binding and promoter activity could be abrogated by mutation of the proximal AP-1 site. Supershift analysis revealed binding of c-Jun and c-Fos to this AP-1 element. Co-expression of c-Jun enhanced promoter activity in Caco-2 cells and activated the promoter in Madin-Darby canine kidney cells. Region and developmental stage-specific expression of ASBT in the rat intestine correlated with the presence of one of these DNA-protein complexes and both c-Fos and c-Jun proteins. A specific AP-1 element regulates transcription of the rat ASBT gene.

Abnormal hepatic sinusoidal bile acid transport in an Amish kindred is not linked to FIC1 and is improved by ursodiol

BACKGROUND & AIMS

The mechanism for abnormal hepatic bile acid transport was investigated in an 18-month-old Amish boy who presented with pruritus, poor growth, and severe bleeding episodes. Serum bilirubin, gamma-glutamyltranspeptidase, and cholesterol levels were normal, but prothrombin time and partial thromboplastin time were prolonged and bone alkaline phosphatase level was elevated.

METHODS AND RESULTS

Cholic acid plus chenodeoxycholic acid levels measured by capillary gas-chromatography were 32 times higher than control in serum (34.7 vs. 1.1+/-0.4 microg/dL) but were not detected in liver and were reduced in gallbladder bile. Treatment with ursodiol, a more hydrophilic bile acid, improved pruritus, produced 37% weight gain, and after 2 years reduced serum primary bile acid concentrations about 85%, while accounting for 71% of serum and 24% of biliary bile acid conjugates. On ursodiol therapy, hepatic bile acid synthesis was enhanced 2-fold compared with controls, and microscopy revealed chronic hepatitis without cholestasis. Three younger sisters with elevated serum bile acids responded positively to ursodiol. Microsatellite markers for the FIC1 (gene for Byler's disease) region in these 4 children were inconsistent with linkage to FIC1.

CONCLUSIONS

Conjugated cholic acid and chenodeoxycholic acid were synthesized in the liver and secreted into bile but could not reenter the liver from portal blood and accumulated in serum. In contrast, unconjugated ursodiol entered the liver and was conjugated and secreted into bile. Thus, the enterohepatic circulation of all conjugated bile acids was interrupted at the hepatic sinusoidal basolateral membrane. Unconjugated ursodiol bypassed the hepatic uptake block to enlarge the biliary and intestinal bile acid pools. A mutation in FIC1 recognized among the Amish and linkage of the disorder to FIC1 were excluded.

Living related liver transplantation for acute liver failure in children

The mortality rate among children with acute liver failure (ALF) on the waiting list for liver transplantation is high. We present our experience with living related donor liver transplantation (LRD-LT) in children who required urgent transplantation for ALF. Between December 1995 and July 1997, 6 children underwent LRD-LT for ALF. Cause of liver failure, recipient and donor demographics, clinical and laboratory data, surgical details, complications, and 6-month and 2-year graft and patient survival were recorded. Five boys and 1 girl received left lateral segment grafts from their parents. The mean age was 4 +/- 2.8 years (range, 1 to 9 years). ALF was caused by Wilson's disease in 1 patient and sickle cell intrahepatic cholestasis syndrome in 1 patient; in 4 patients, the cause was unknown. All patients had mental status changes; 2 were on life support. Mean pretransplantation liver function test values were: alanine aminotransferase, 972 +/- 565 U/L (normal, 1 to 53 U/L), total bilirubin, 31.3 +/- 12.4 mg/dL (normal, 0.1 to 1.2 mg/dL), prothrombin time, 34.3 +/- 12.4 seconds (normal, 10.8 to 13.3 seconds), international normalized ratio, 8.46 +/- 5.4 (normal < 2), and fibrinogen, 109 +/- 23.9 mg/dL (normal, 175 to 400 mg/dL). The donors were 5 mothers and 1 father. The mean donor age was 32.5 +/- 7.6 years (range, 19 to 40 years). No donor required blood transfusion, and no donor had any early or late postoperative complications. The donors' mean hospital length of stay was 5 days. In five cases, grafts were blood group-compatible; 1 child received a blood group-incompatible graft. All grafts functioned immediately. No patient had hepatic artery or portal vein thrombosis or biliary complications. The child who received a mismatched graft died of infection of the brain caused by Aspergillus spp at 22 days posttransplantation with a functioning graft. The child with ALF caused by sickle cell intrahepatic cholestasis syndrome developed outflow obstruction 3 months posttransplantation and required retransplantation; he eventually died of vascular complications related to his primary disease. Four children are alive at a mean follow-up of 27 months (range, 14 to 36 months). LRD-LT for children with ALF facilitates timely transplantation without drawing on cadaveric donor resources. The established safety record of LRD-LT made this option appealing to both physicians and parental donors.

A prospective analysis of cholestasis in infants supported with extracorporeal membrane oxygenation

Cholestasis develops in many infants supported with extracorporeal membrane oxygenation. We prospectively investigated the role of hemolysis and di-(2-ethylhexyl) phthalate exposure in the development of this cholestasis. Both di-(2-ethylhexyl) phthalate levels and hemolysis, as measured by maximum free hemoglobin, were significantly (p less than 0.025) associated with the degree of cholestasis. Other clinical and laboratory factors that may contribute to cholestasis were also investigated and not found to be related to the degree of cholestasis. We speculate that hemolysis during extracorporeal membrane oxygenation support produces a large bilirubin load whose excretion is inhibited by mechanisms similar to the inspissated bile syndrome and/or by di-(2-ethylhexyl) phthalate. This would result in a predominantly direct hyperbilirubinemia with little evidence of hepatocellular or canalicular injury.

The effect of biliary enteroenterostomy on the pharmacokinetics of enterally administered cyclosporine in rats

A major factor in poor bioavailability of cyclosporine in children undergoing orthotopic liver transplantation appears to be poor absorption of the drug. Our hypothesis is that the Roux-en-Y choledochojejunostomy used for biliary drainage in these children causes cyclosporine malabsorption by reducing the length of bowel available for absorption and by distally displacing the entry of bile into the intestine. In these experiments, we determined the effect of biliary enteroenterostomy on the pharmacokinetics of enterally administered cyclosporine in Sprague-Dawley rats. Experimental rats (n = 24) were prepared for study by constructing self-emptying jejunal blind loops. Sham rats (n = 9) had jejunal transection and reanastomosis. Control rats (n = 26) had no operation. Two to 4 weeks later, chronic biliary-enteric fistulae were formed in all animals. In experiments, [3H]cyclosporine was delivered into the duodenum while the site of bile delivery varied. Hourly and cumulative [3H]cyclosporine excretion into bile was quantitated, which our preliminary data show to be a valid estimate of absorption. In control rats, bile was delivered into the duodenum or was replaced with saline and sucrose solution. In experimental rats, bile was infused either into the duodenum, which tested bowel shortening only, or into the proximal end of the blind loop, which tested the combined effects of bowel shortening and distal displacement of bile entry. In sham rats, bile was infused into the duodenum, which controlled for previous abdominal surgery, or into the midjejunum, which tested for distal bile entry only. Two effects of biliary enteroenterostomy on cyclosporine absorption were observed.(ABSTRACT TRUNCATED AT 250 WORDS)