The concentration of serum bile acids during the course of acute hepatitis B

Farnesoid X Receptor Activation Decreases Toll-like Receptor 2 Expression by Upregulating HBeAg Production

Background: Previous investigations have demonstrated that hepatitis B virus (HBV) infection leads to elevated serum bile acid levels, which is considered to cause liver damage. Thus, we suppose that bile acids may be of considerable significance in inducing immune tolerance. Methods: In this investigation, we explored the functions of the farnesoid X receptor (FXR), a nuclear receptor activated by bile acids, in modulating hepatitis B e antigen (HBeAg) production and toll-like receptor (TLR) expression in vitro and in vivo. Results: The results showed that FXR activation promoted secreted and intracellular HBeAg expression in HepG2 and HEK293T cells. However, FXR antagonist Z-guggulsterone (Z-g) decreased the bile acid-mediated HBeAg production. Meanwhile, TLR2 expression significantly reduced in HepG2 cells transfected with pAAV/HBV1.2 plasmid comprising whole HBV genome and treated with bile acids, but not with mutant pAAV/HBV1.2 plasmid with defected HBeAg product. In the hydrodynamic injection HBV mouse model, the level of serum HBeAg was decreased, but intrahepatic TLR2 expression was elevated in FXR-/- mice. Conclusions: In conclusion, FXR activation inhibits TLR2-mediated innate immunity by upregulating HBeAg production. Our data indicate that a mild elevation of serum bile acids may cause immune tolerance and lead to virus persistence in HBV-infected patients.

Effect of ursodeoxycholic acid administration in patients with acute viral hepatitis: a pilot study

BACKGROUND

Ursodeoxycholic acid (UDCA) is able to improve biochemical markers of cholestasis, with a parallel decrease in transaminases, in various cholestatic liver diseases.

AIM

To evaluate the effects of UDCA administration on acute viral hepatitis-related cholestasis and the course of acute viral hepatitis.

METHODS

Seventy-nine consecutive patients with acute viral hepatitis (HBV: 43, HCV: 11, HAV: 15, HEV: 3, Non A-E: 7) were randomized to receive either UDCA for 3 weeks or no treatment. Liver biochemistry and serum bile acid determinations were run at weekly intervals.

RESULTS

No significant differences were observed in mean percentage decreases in transaminases between treated and untreated patients. By contrast, cholestatic indexes decreased significantly more quickly in patients treated with UDCA than in controls, and this effect was more evident in patients with increasing alanine transaminase levels at admission. After a peak at the end of the first week of therapy, serum levels of conjugated ursodeoxycholic acid (CUDCA) showed a gradual decrease. Conjugated cholic acid (CCA) and chenodeoxycholic acid (CCDCA) showed a progressive decrease with the resolution of viral hepatitis, but no influence of UDCA administration was observed.

CONCLUSIONS

Our study demonstrates that UDCA significantly improves cholestatic indices in patients with acute viral hepatitis, but this effect does not seem to affect the course of the illness.

Bile acids in health and disease

Over the last quarter of a century Danish research on bile acids has comprised studies of their physical and chemical properties, their physiology, pathophysiology, metabolism, and kinetics, and their clinical applicability. In the beginning of the period a major contribution was made to the understanding of the factors involved in the solubility of cholesterol in bile. The growing international understanding of the potential importance of the bile acids in health and disease gave raise to a substantial Danish contribution in the 1970s and 1980s in parallel with international achievements. Emphasis was on the possible clinical implications of bile acids. Studies on physiology and pathophysiology were in focus. Patients who have had an intestinal bypass operation for obesity served as a model for obtaining new knowledge on various aspects of the properties of the bile acids. Also the analytical methods were improved. Important physiological research on the mechanisms of hepatic bile flow was conducted. An intestinal perfusion model served as a tool providing information on absorption kinetics and on transmucosal water and electrolyte movements. The gallstone disease, liver diseases, inflammatory bowel disease, fat malabsorption, and other intestinal disorders were studied. The 'idiopathic ileopathy' as a cause for bile acid malabsorption causing diarrhoea was established as a new disorder. Thus, in the time period concerned, substantial Danish contributions emerged on major and minor topics of the bile acid field.

Diagnostic values of fasting and postprandial concentrations in serum of 3 alpha-hydroxy-bile acids and gamma-glutamyl transferase in hepatobiliary disease

Fasting and postprandial concentrations in serum of 3 alpha-hydroxy-bile acids and gamma-glutamyl transferase were measured in 138 consecutive patients, 62 with (D) and 76 without (D) hepatobiliary disease. The maximum efficiencies of the three tests--that is, the fractions of patients allocated correctly to the D or D group at the optimum discrimination values--were 0.85, 0.84, and 0.83, respectively. Furthermore, the predictive values and nosographic sensitivities and specificities were rather similar. When the three tests were combined, the nosographic sensitivity increased significantly to a value of 0.84, and the corresponding specificity was 0.91. The diagnostic value of the absolute postprandial increase in serum bile acid concentration was slightly inferior to the diagnostic values of the fasting and postprandial serum bile acid concentrations and, finally, the relative postprandial serum bile acid increase was of no diagnostic value at all.