Electron microscopic assessment of bile regurgitation of humans in extrahepatic obstructive jaundice

Changes in Glutathione Content in Liver Diseases: An Update

Glutathione (GSH), a tripeptide particularly concentrated in the liver, is the most important thiol reducing agent involved in the modulation of redox processes. It has also been demonstrated that GSH cannot be considered only as a mere free radical scavenger but that it takes part in the network governing the choice between survival, necrosis and apoptosis as well as in altering the function of signal transduction and transcription factor molecules. The purpose of the present review is to provide an overview on the molecular biology of the GSH system; therefore, GSH synthesis, metabolism and regulation will be reviewed. The multiple GSH functions will be described, as well as the importance of GSH compartmentalization into distinct subcellular pools and inter-organ transfer. Furthermore, we will highlight the close relationship existing between GSH content and the pathogenesis of liver disease, such as non-alcoholic fatty liver disease (NAFLD), alcoholic liver disease (ALD), chronic cholestatic injury, ischemia/reperfusion damage, hepatitis C virus (HCV), hepatitis B virus (HBV) and hepatocellular carcinoma. Finally, the potential therapeutic benefits of GSH and GSH-related medications, will be described for each liver disorder taken into account.

Initial site of bile regurgitation following extrahepatic biliary obstruction in living rats

BACKGROUND AND AIM

The precise mechanism of bile regurgitation from the biliary system to the blood stream still remains to be elucidated. The aim of this study was to examine the initial site of bile regurgitation in vivo after common bile duct (CBD) obstruction by digitally enhanced fluorescence microscopy.

METHODS

The fluorescence excreted into bile canaliculi after the administration of sodium fluorescein was continuously observed in CBD obstruction, using video-enhanced contrast (VEC) microscopy equipped with a silicon intensified target (SIT) camera. The liver histology and the localization of Mg(2+)-ATPase were examined by light and electron microscopy.

RESULTS

By the continuous recording of canalicular fluorescence, the sequential regurgitation of the fluorescence from the canaliculi to the hepatocyte cytoplasm to the sinusoids was distinctively recognized after CBD obstruction. Bile canalicular fluorescence was enhanced, and then the fluorescence of the hepatocyte cytoplasm increased in intensity, followed by regurgitation of the fluorescence to the sinusoids. These in vivo sequences closely correlated with changes in CBD pressure. In zone 1, canalicular fluorescence focally burst into hepatocyte cytoplasm, thus resulting in the formation of fluorescent cells. By light and electron microscopy, the fluorescent cells were found to correspond to the liver cell injury. The reaction products of Mg(2+)-ATPase were incorporated into vesicles with a decreased canalicular activity, and then were transported to the sinusoidal surface after CBD obstruction.

CONCLUSIONS

The initial site of bile regurgitation may be transcellular, and partly involves liver cell injury in zone 1 in extrahepatic biliary obstruction, associated with increased pressure of the biliary system.

Bacterial translocation from the biliary tract to blood and lymph in rats with obstructive jaundice

BACKGROUND

The disruption of the hepatocyte tight junctions observed in biliary obstruction suggests altered permeability of the blood-bile barrier. In this study the role of biliary obstruction and increased biliary pressure on the translocation of bacteria from biliary tract to bloodstream and lymphatic system were evaluated.

MATERIALS AND METHODS

Rats underwent distal bile duct ligation (BDL, n = 33) for two weeks or a sham celiotomy (n = 21). Seventeen of the 33 BDL rats underwent subsequent biliary decompression by a choledochojejunostomy (CJ). Two weeks after the final operation, a laparotomy was performed again and the CBD, the thoracic duct, and the caval vein were canulated. Next, a suspension containing 10(8) Escherichia coli/ml was retrogradely infused in the CBD for 5 min at 5 or 20 cm H2O above the secretory biliary pressure.

RESULTS

A higher biliary infusion pressure resulted in a significant increase of cfu E.coli per milliliter of blood in all the three groups (Sham, BDL, CJ). BDL rats showed significantly more bacterial translocation to the bloodstream than the shams. After biliary decompression, translocation normalized to the control levels. At 5 cm H2O infusion pressure only one lymph culture was positive (CJ group). At 20 cm H2O overpressure, nine lymph cultures were E.coli positive (P = 0.03). These were found mainly in groups with a nonobstructed bile duct (Sham and CJ 40% vs BDL 10%).

CONCLUSION

Translocation of bacteria from biliary tract to bloodstream increased at higher intrabiliary pressures. Longstanding bile duct obstruction was an independent determinant for cholangiovenous reflux. Bacterial translocation to the lymphatic system did not parallel translocation to the bloodstream, although in the nonobstructed biliary tract, increased bacterial translocation to the lymphatic system was pressure related.

Influence of biliary drainage catheter on bile duct wall thickness as measured by intraductal ultrasonography

OBJECTIVE

To determine the influence of biliary drainage catheter placement on bile duct wall thickness, we performed intraductal ultrasonography (IDUS) in patients before and after biliary drainage.

METHODS

Patients underwent IDUS before and after either short-term (n = 9, 6 to 8 days) or long-term (n = 9, 14 to 35 days) biliary drainage using a thin (2.0 mm diameter), 20 MHz probe inserted by means of a transpapillary route or a percutaneous tract. The bile duct wall thickness (mean +/- standard deviation) was retrospectively measured at the upper portion of the common hepatic duct.

RESULTS

The bile duct wall thickness increased from 0.8+/-0.4 mm (predrainage) to 2.0+/-1.6 mm (post-drainage) in the long-term group (p < 0.001) but was not significantly increased in the short-term group.

CONCLUSIONS

The bile duct wall thickness as measured on IDUS appears to be increased after placement of biliary drainage catheters.

Cholangiovenous reflux pathways as defined by corrosion casting and scanning electron microscopy

Using corrosion casting and scanning electron microscopy of the rat biliary tree, we investigated the site and size of the pathways that allow bacteria to reflux from bile to blood. Nonobstructed rat biliary trees were injected retrograde with methylmethacrylate resin at a constant rate of 0.04 ml/min to volumes of 40, 60, 80, 120, 160, and 200 microliters. The infusion pressure was monitored and a pressure-volume curve was constructed. After polymerization and corrosion in 30 percent potassium hydroxide, the casts were examined with scanning electron microscopy. In addition, to identify the size of the reflux pathways, ceramic particles of 150 A, 1.7 mu, or 10 mu were added to the resin, and the studies were repeated. Finally, intact livers with casted biliary trees were processed and studied by scanning electron microscopy without corrosion. Scanning electron microscopy demonstrated fine anatomic detail of the cholangiovenous reflux pathway. At 40 microliters (20 cm water pressure), normal biliary radicals were filled. Between 40 and 80 microliters (20 to 50 cm water pressure), the cast material refluxed from the bile ductules into the spaces of Mall and Disse and then into the hepatic sinusoids. Filling of sinusoids continued at volumes between 80 to 160 microliters, and filling of collecting veins was seen above 160 microliters. Particles of 1.7 mu and smaller readily refluxed, but there was no sinusoidal reflux of casting material that contained particles of 10 mu. Casting without corrosion showed that the liver parenchyma remained intact. There was no evidence of reflux across hepatocytes. This study shows that cholangiovenous reflux occurs directly from bile ductules through the spaces of Mall and Disse into the hepatic sinusoids. The pathways measure between 1.7 and 10 mu. Since this is the path of least resistance, it may be of greater importance in the reflux of bacteria and toxins than other high-resistance pathways, for example, biliary canaliculi, tight junctions, or hepatocytes.