Biliary Secretion of Quasi-Enveloped Human Hepatitis A Virus.

Hepatitis A virus (HAV) is an unusual picornavirus that is released from cells cloaked in host-derived membranes. These quasi-enveloped virions (eHAV) are the only particle type circulating in blood during infection, whereas only nonenveloped virions are shed in feces. The reason for this is uncertain. Hepatocytes, the only cell type known to support HAV replication in vivo, are highly polarized epithelial cells with basolateral membranes facing onto hepatic (blood) sinusoids and apical membranes abutting biliary canaliculi from which bile is secreted to the gut. To assess whether eHAV and nonenveloped virus egress from cells via vectorially distinct pathways, we studied infected polarized cultures of Caco-2 and HepG2-N6 cells. Most (>99%) progeny virions were released apically from Caco-2 cells, whereas basolateral (64%) versus apical (36%) release was more balanced with HepG2-N6 cells. Both apically and basolaterally released virions were predominantly enveloped, with no suggestion of differential vectorial release of eHAV versus naked virions. Basolateral to apical transcytosis of either particle type was minimal (<0.02%/h) in HepG2-N6 cells, arguing against this as a mechanism for differences in membrane envelopment of serum versus fecal virus. High concentrations of human bile acids converted eHAV to nonenveloped virions, whereas virus present in bile from HAV-infected Ifnar1-/- Ifngr1-/- and Mavs-/- mice banded over a range of densities extending from that of eHAV to that of nonenveloped virions. We conclude that nonenveloped virions shed in feces are derived from eHAV released across the canalicular membrane and stripped of membranes by the detergent action of bile acids within the proximal biliary canaliculus. IMPORTANCE: HAV is a hepatotropic, fecally/orally transmitted picornavirus that can cause severe hepatitis in humans. Recent work reveals that it has an unusual life cycle. Virus is found in cell culture supernatant fluids in two mature, infectious forms: one wrapped in membranes (quasi-enveloped) and another that is nonenveloped. Membrane-wrapped virions circulate in blood during acute infection and are resistant to neutralizing antibodies, likely facilitating HAV dissemination within the liver. On the other hand, virus shed in feces is nonenveloped and highly stable, facilitating epidemic spread and transmission to naive hosts. Factors controlling the biogenesis of these two distinct forms of the virus in infected humans are not understood. Here we characterize vectorial release of quasi-enveloped virions from polarized epithelial cell cultures and provide evidence that bile acids strip membranes from eHAV following its secretion into the biliary tract. These results enhance our understanding of the life cycle of this unusual picornavirus.

Papillomatosis of intra- and extrahepatic biliary tree: Successful treatment with liver transplantation.

Approximately 60 cases of biliary papillomatosis have been reported in the world literature, while only 6 cases have been reported to be treated with liver transplantation. This rare disease, which is characterized by relapsing episodes of obstructive jaundice and cholangitis that lead to secondary cirrhosis and death from sepsis or liver failure, it is also considered premalignant because of its frequent malignant transformation (25-50%). We present a case of a 43-year-old white man with papillomatosis of intra- and extrahepatic biliary tree who sought care for repeated episodes of obstructive jaundice and cholangitis. The diagnosis was suspected after endoscopic retrograde cholangiopancreatography and confirmed by liver and common bile duct biopsies. The patient underwent orthotopic liver transplantation with Roux-en-Y hepatico-jejunostomy to treat end-stage liver cirrhosis. Fifteen months' follow-up revealed a patient with normal graft function and with no clinically or laboratory findings of disease recurrence or cancer development.

Expression of NF-kappaB in rotavirus-induced damage to the liver and biliary tract in neonatal mice.

BACKGROUND: Biliary atresia, the etiology of which still remains unclear, occurs exclusively in newborns and most are infected with rotavirus. In this study, we aimed to investigate the histopathological patterns of different kinds of rotavirus in the liver and biliary tract of neonatal mice and the expression of NF-kappaB in the liver and biliary tract of infected mice. METHODS: Twenty-three adult mice (8 were male and 15 female) were divided into 8 breeding pairs, and each pair (1 male and 2 females) was housed in a cage in a laminar flow hood. Newborn mice, 24-48 hours old were randomly divided into A, B and C groups. The A and B groups were respectively inoculated with MMU18006 and SA11 rotavirus through the intraperitoneal route, while group C as blank control was only inoculated with culture medium. The liver was dissected after 5, 10, 15, 21 and 28 days; the weight of each mouse and the histopathological patterns in the liver were recorded. The expression of NF-kappaB in the liver and intrahepatic bile ducts was detected by immunohistochemical staining and the expression intensity was analyzed with a GT-2 imaging instrument. RESULTS: The average increase in weight of infected mice was significantly slower than that of the normal control, while the growth rate of group A (injected with MMU18006 rotavirus) was slower than that of group B (SA11 rotavirus). In infected mice, the acute and chronic inflammation of liver and intra- and extra-hepatic bile ducts was more significant in group A. Stenosis was found in most intrahepatic bile ducts, and sporadically in extrahepatic bile ducts. The expression of NF-kappaB in infected mice was dramatically higher than that of the normal control, while the expression in group A was higher than in group B. CONCLUSIONS: Significant damage to the liver and biliary tract of neonatal mice can be induced by inoculating MMU18006 rotavirus through the intraperitoneal route, which is very similar to the pathology of biliary atresia in the newborn human. Similar inoculation with SA11 rotavirus can only result in moderate impairment that disappears quickly. The difference of pathogenicity between the two rotaviruses may depend on their differing capacities to increase the expression of NF-kappaB in the liver and biliary tract.

Permissiveness of human biliary epithelial cells to infection by hepatitis C virus.

The cellular tropism of hepatitis C virus (HCV) is an important but much debated issue. Permissivity to HCV of biliary cells has never been demonstrated. In this context, we used gallbladder epithelial cells (GBEC) as a model of the more proximal biliary epithelium. These cells were isolated from HCV-positive and -negative individuals and cultured for up to 40 days. Biliary cells from HCV-negative subjects were infected in vitro with various inocula. The retention of GBEC functional characteristics was assessed by the expression of cystic fibrosis transmembrane conductance regulator (CFTR). All 12 GBEC tested from HCV-negative patients were successfully infected by HCV. This was assessed by: 1) the detection of HCV-RNA positive and negative strands; 2) the detection of the viral capsid by immunofluorescence; and 3) the combination of single-strand conformation polymorphism (SSCP) and HVR1 sequence analysis demonstrating the distinct majoritary HCV genomes in serum and in GBEC. The level of HCV RNA in cell extracts and supernatants was low, but HCV infection was highly reproducible. Our results expand those showing the cellular tropism of HCV, and demonstrate the sensitivity of biliary cells to HCV infection. This might have an important impact in terms of pathogenesis and pathological features of HCV infection. In addition, given the easy access to these cells and the high reproducibility of in vitro infection, they should constitute an important tool for studies aimed at analyzing the issue of HCV penetration and neutralizing antibodies.

Cytomegalovirus infection in children's liver tissues.

Immunoperoxidase histochemical assay with monoclonal antibody against human cytomaglovirus (HCMV) was used to detect immediate early antigen (IEA) and early antigen (EA) of HCMV infection in liver tissue of 72 pediatric cases (34 autopsies and 38 biopsies). The HCMV antigen was positive in 25% (18/27). Among them, 12 cases were both HCMV-IEA and EA positive; 4 were HCMV-IEA positive and 2 HCMV-EA positive only. Liver HCMV infection rate in neonates, the infants with the age < 1 year and > 1 year was 8.0%, 60.0%, and 14.8%, respectively, indicating that liver HCMV infection occurred at various ages. The liver HCMV infection rate in different diseases was 50.0% in infantile hepatitis syndrome; 70.0% in extrabiliary malformation, and 12.5% in other hepatopathies, suggesting that infantile hepatitis syndrome and extrabiliary malformation were related with HCMV infection in liver tissues.