Publications

It is uncertain whether occult hepatitis B virus co-infection will hasten progressive liver disease in chronic hepatitis C patients after liver transplantation. This study evaluated fibrosis progression and severe fibrosis in 118 consecutive hepatitis B surface antigen-negative patients with virological and histological evidence of recurrent chronic hepatitis C infection co-infected with occult hepatitis B virus after liver transplantation. HBV DNA was detected from serum at the time of recurrent chronic hepatitis C infection by polymerase chain reaction. Each subject underwent a repeat liver biopsy 5 years post-liver transplantation. Occult hepatitis B virus co-infection was present in 41 of the 118 (34.7%) patients. At 5 years post-liver transplantation, 13 of the 41 occult hepatitis B virus co-infected patients compared with 16 of the 77 patients without occult hepatitis B virus co-infection developed fibrosis progression (31.7% vs. 20.8%, respectively, p = 0.39). Eight of 41 the occult hepatitis B virus co-infected patients compared with 13 of the 77 patients without occult hepatitis B virus co-infection had severe fibrosis (19.5% vs. 16.9%, respectively, p = 0.97). In conclusion, occult hepatitis B virus co-infection in patients with recurrent chronic hepatitis C infection was not associated with accelerated fibrosis progression or severe fibrosis after liver transplantation.

OBJECTIVES

The aim of this study was to further explore the severity of liver disease and its predictors in a cohort of hepatitis C virus (HCV) infected patients, some of whom were coinfected with the human immunodeficiency virus (HIV).

METHODS

This is a retrospective, cross-sectional study of patients undergoing liver biopsy to stage HCV disease prior to consideration of anti-HCV therapy.

RESULTS

A total of 92 HIV-HCV coinfected and 372 HCV monoinfected patients were included. As might be expected, coinfected patients differed from monoinfected patients in a number of ways, including having lower body mass index (BMI), and lower alcohol intake. Liver disease was very similar between the two groups, with mean fibrosis score of 1.45 u for coinfected and 1.53 u for monoinfected (p = NS). Histological inflammation score dominated multivariate models of fibrosis when it was included in them. When only clinical predictors were used in multivariate models, BMI and type 2 diabetes had independent associations in monoinfected patients, whereas low CD4 count, current or nadir, was the only variable with an independent association in coinfected patients.

CONCLUSIONS

Coinfected patients do not have uniformly worse liver disease than monoinfected patients. Immune compromise plays an important role in liver disease in coinfected patients, and the role of other clinical factors in liver disease may differ between these two groups, as well.

Growth cones are highly polarized and dynamic structures confined to the tips of axons. The polarity of growth cones is in part maintained by suppression of protrusive activity from the distal axon shaft, a process termed axon consolidation. The mechanistic basis of axon consolidation that contributes to the maintenance of growth cone polarity is not clear. We report that inhibition of RhoA-kinase (ROCK) or myosin II resulted in unstable consolidation of the distal axon as evidenced by increased filopodial and lamellipodial extension. Furthermore, when ROCK or myosin II was inhibited lamellipodia formed at the growth cone migrated onto the axon shaft. Analysis of EYFP-actin dynamics in the distal axon revealed that ROCK negatively regulates actin polymerization and initiation of protrusive structures from spontaneously formed axonal F-actin patches, the latter being an effect attributable to ROCK-mediated regulation of myosin II. Inhibition of ROCK or myosin II blocked growth cone turning toward NGF by preventing suppression of protrusive activity away from the source of NGF, resulting in aborted turning responses. These data elucidate the mechanism of growth cone polarity, provide evidence that consolidation of the distal axon is a component of guidance, and identify ROCK as a negative regulator of F-actin polymerization underlying protrusive activity in the distal axon.

Progressive familial intrahepatic cholestasis type 1 (PFIC1, Byler disease, OMIM 211600) is a severe inherited liver disease caused by mutations in ATP8B1. ATP8B1 is a member of the type 4 subfamily of P-type ATPases, which are phospholipid flippases. PFIC1 patients generally develop end-stage liver disease before the second decade of life. The disease is characterized by impaired biliary bile salt excretion, but the mechanism whereby impaired ATP8B1 function results in cholestasis is unclear. In a mouse model for PFIC1, we observed decreased resistance of the hepatocanalicular membrane to hydrophobic bile salts as evidenced by enhanced biliary recovery of phosphatidylserine, cholesterol, and ectoenzymes. In liver specimens from PFIC1 patients, but not in those from control subjects, ectoenzyme expression at the canalicular membrane was markedly deficient. In isolated mouse livers Atp8b1 deficiency impaired the transport of hydrophobic bile salts into bile. In conclusion, our study shows that Atp8b1 deficiency causes loss of canalicular phospholipid membrane asymmetry that in turn renders the canalicular membrane less resistant toward hydrophobic bile salts. The loss of phospholipid asymmetry may subsequently impair bile salt transport and cause cholestasis.