Ursodeoxycholic acid protects against secondary biliary cirrhosis in rats by preventing mitochondrial oxidative stress

Liver fibrosis caused by choledocholith to regress after biliary drainage

AIM: To study the correlation between liver fibrosis severity and biliary drainage in patients with choledocholith.

METHODS: A follow-up study on seven patients with liver fibrosis due to choledocholith was made. The data, including biochemical tests (aspartate aminotransferase, alanine aminotransferase) and liver histological features before and after biliary drainage, were collected and studied. The fibrosis severity was scored on a scale from 0 to 3, with 0 denoting none, 1 portal and periportal fibrosis, 2 the presence of numerous fiber septa, and 3 cirrhosis. The average liver fibrosis severity scores of the first and second biopsy were compared with statistical method.

RESULTS: The first, second liver fibrosis severity scores of these seven patients were 2,1; 2,1; 1,0; 1,1; 2,1; 2,1; 1,0 respectively. The results showed that the average liver fibrosis severity score of the second liver biopsy decreased significantly compared with the first liver biopsy (n = 7, t = 4.25, P<0.05).

CONCLUSION: Liver fibrosis due to choledocholith may regress after biliary drainage.

Maternal cholestasis induces placental oxidative stress and apoptosis. Protective effect of ursodeoxycholic acid

We have investigated whether maternal obstructive cholestasis during pregnancy (OCP) causes oxidative stress and apoptosis in rat placenta and whether treatment with ursodeoxycholic acid (UDCA, i.g., 60 microg/100 g b.wt./day, following complete biliary obstruction on day 14 of pregnancy) has protective effects on this organ. In rats with OCP, increased (15-fold) serum bile acid concentrations (BAs) together with signs of placental oxidative stress (lipid peroxidation and protein carbonylation) were found. The latter were partly prevented by UDCA, even though hypercholanemia was not corrected. Some elements of the antioxidant system (total glutathione content, GSH/GSSG ratio and catalase, glutathione peroxidase, and glutathione-S-transferase--but not glutathione reductase--activities) were impaired in placentas from the OCP group. UDCA treatment partly prevented changes in the antioxidant system. OCP induced an increase in Bax-alpha/Bcl-2 mRNA ratio, as determined by real-time quantitative PCR, suggesting enhanced susceptibility to apoptosis activation through the mitochondria-mediated pathway. Accordingly, the activity of caspase-3, but not caspase-8, was increased in OCP placentas, in which DNA-ladder analysis and TUNEL confirmed the existence of apoptosis. UDCA prevented changes in the Bax-alpha/Bcl-2 mRNA ratio and caspase-3 activity. In conclusion, OCP causes oxidative stress and apoptosis in rat placenta, which can be prevented by treatment with UDCA.

Oxidative damage is a potential cause of cone cell death in retinitis pigmentosa

Retinitis pigmentosa (RP) is a prevalent cause of blindness caused by a large number of different mutations in many different genes. The mutations result in rod photoreceptor cell death, but it is unknown why cones die. In this study, we tested the hypothesis that cones die from oxidative damage by performing immunohistochemical staining for biomarkers of oxidative damage in a transgenic pig model of RP. The presence of acrolein- and 4-hydroxynonenal-adducts on proteins is a specific indicator that lipid peroxidation has occurred, and there was strong immunofluorescent staining for both in cone inner segments (IS) of two 10-month-old transgenic pigs in which almost all rods had died, compared to faint staining in two 10-month-old control pig retinas. In 22- and 24-month-old transgenic pigs in which all rods and many cones had died, staining was strong in cone axons and some cell bodies as well as IS indicating progression in oxidative damage between 10 and 22 months. Biomarkers for oxidative damage to proteins and DNA also showed progressive oxidative damage to those macromolecules in cones during the course of RP. These data support the hypothesis that the death of rods results in decreased oxygen consumption and hyperoxia in the outer retina resulting in gradual cone cell death from oxidative damage. This hypothesis has important therapeutic implications and deserves rapid evaluation.