Loss of keratin 19 favours the development of cholestatic liver disease through decreased ductular reaction.

Keratins (K) are cytoprotective proteins and keratin mutations predispose to the development of multiple human diseases. K19 represents the most widely used marker of biliary and hepatic progenitor cells as well as a marker of ductular reaction that constitutes the basic regenerative response to chronic liver injury. In the present study, we investigated the role of K19 in biliary and hepatic progenitor cells and its importance for ductular reaction. K19 wild-type (WT) and knockout (KO) mice were fed: (a) 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC); (b) cholic acid (CA); (c) a choline-deficient, ethionine-supplemented (CDE) diet; or (d) were subjected to common bile duct ligation (CBDL). The bile composition, liver damage, bile duct proliferation, oval cell content and biliary fibrosis were analysed. In untreated animals, loss of K19 led to redistribution of the K network in biliary epithelial cells (BECs) but to no obvious biliary phenotype. After DDC feeding, K19 KO mice exhibited (compared to WTs): (a) increased cholestasis; (b) less pronounced ductular reaction with reduced ductular proliferation and fewer oval cells; (c) impaired Notch 2 signalling in BECs; (d) lower biliary fibrosis score and biliary bicarbonate concentration. An attenuated oval cell proliferation in K19 KOs was also found after feeding with the CDE diet. K19 KOs subjected to CBDL displayed lower BEC proliferation, oval cell content and less prominent Notch 2 signal. K19 deficiency did not change the extent of CA- or CBDL-induced liver injury and fibrosis. Our results demonstrate that K19 plays an important role in the ductular reaction and might be of importance in multiple chronic liver disorders that frequently display a ductular reaction.

Telmisartan plus propranolol improves liver fibrosis and bile duct proliferation in the PSC-like Abcb4-/- mouse model.

BACKGROUND: Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease leading to cirrhosis and cholangiocellular carcinoma. Inhibitors of the renin-angiotensin system or the sympathetic nervous system delay liver fibrogenesis in animal models. AIMS: We investigated the antifibrotic potential of telmisartan, an angiotensin II type 1 receptor antagonist, and the ß-adrenoceptor blocker propranolol in the PSC-like Abcb4 knockout mouse model. METHODS: Sixty-five Abcb4 (-/-) mice were treated with telmisartan for 3 or 5 months (T) and with telmisartan plus propranolol for 3, 5, or 8 months (TP), or for 2 or 5 months starting with a delay of 3 months (TP delayed). Liver hydroxyproline content, inflammation, fibrosis, and bile duct proliferation were assessed; fibrosis-related molecules were analyzed by real-time polymerase chain reaction and Western blotting. RESULTS: Compared to controls, telmisartan monotherapy had no significant influence on hydroxyproline; however, telmisartan plus propranolol reduced hydroxyproline (TP 3 months, p = 0.008), fibrosis score (TP 3 months and TP 8 months, p = 0.043 and p = 0.008, respectively; TP delayed 8 months, p < 0.0005), bile duct proliferation (TP 8 months and TP delayed 8 months, p = 0.006 and p < 0.0005, respectively), and procollagen α1(I), endothelin-1, TIMP-1 and MMP3 mRNA as well as α-SMA, CK-19, and TIMP-1 protein. CONCLUSIONS: Telmisartan plus propranolol reduces liver fibrosis and bile duct proliferation in the PSC-like Abcb4 (-/-) mouse model, even when started at late stages of fibrosis, and may thus represent a novel therapeutic option for cholestatic liver diseases such as PSC.

Curcumin improves sclerosing cholangitis in Mdr2-/- mice by inhibition of cholangiocyte inflammatory response and portal myofibroblast proliferation.

BACKGROUND AND AIM: Chronic cholangiopathies have limited therapeutic options and represent an important indication for liver transplantation. Curcumin, the yellow pigment of the spice turmeric, has pleiotropic actions and attenuates hepatic damage in animal models of chemically-induced liver injury. Whether curcumin has beneficial effects in cholangiopathies is unknown. METHODS: Potential anticholestatic, anti-inflammatory and antifibrotic mechanisms of curcumin were explored in vivo in Mdr2(-/-) mice as a murine model of chronic cholangiopathy; as well as in vitro in a cholangiocyte cell line (HuCCT1) and portal myofibroblasts (MFBs) isolated from Mdr2(-/-) mice. RESULTS: Liver damage, cholestasis and fibrosis were reduced in Mdr2(-/-) mice after curcumin feeding. Moreover, curcumin inhibited cholangiocyte proliferation and expression of activation marker vascular cell adhesion molecule-1 in Mdr2(-/-) mice. Curcumin-similar to PPARgamma synthetic agonist troglitazone-directly inhibited TNF-alpha-induced inflammatory activation of cholangiocytes in vitro, whereas these beneficial effects of curcumin were largely blocked by a PPARgamma synthetic antagonist. In addition, curcumin blocked proliferation and activation of portal MFBs by inhibiting ERK1/2 phosphorylation, thus contributing to reduced fibrogenesis. CONCLUSIONS: These results show that curcumin may have multiple targets in liver including activation of PPARgamma in cholangiocytes and inhibition of ERK1/2 signalling in MFBs, thereby modulating several central cellular events in a mouse model of cholangiopathy. Targeting these pathways may be a promising therapeutic approach to cholangiopathies.

Hepatic retention of copper and selenium in primary sclerosing cholangitis.

BACKGROUND: Previous studies have suggested abnormal copper metabolism in patients with primary sclerosing cholangitis (PSC). In the present work the trace element metabolism was studied in a group of 32 patients with PSC. METHODS: Hepatic copper and selenium concentrations were determined with a sensitive electrothermal atomic absorption technique. Serum concentrations of copper and zinc were determined by conventional atomic absorption. RESULTS: For the patient group serum copper values (20.3 +/- 4.5 mumol/l) were higher than those for the control group (14 +/- 3 mumol/l), and average hepatic copper concentrations were greater by a factor of four. Serum selenium values were slightly lower, although the average hepatic selenium was significantly higher than in the healthy control group. Previous studies have discussed possible toxic effects of hepatocellular copper accumulation, which may be accompanied by formation of activated oxygen species and depletion of glutathione. In the present study, however, it could not be demonstrated that the concentration of the lipoperoxidation product, malonic dialdehyde, was higher than normal in blood. Furthermore, blood concentrations of glutathione and glutathione peroxidase were not abnormal. CONCLUSION: Although a protective effect of the raised selenium concentrations in the liver might be discussed, it is apparent that the copper accumulation in the liver cells described here did not induce detectable changes in the indices studied.

Assessment of nutritional status of patients with end-stage liver disease undergoing liver transplantation.

Nutritional assessment factors (including dietary history, anthropometric and biochemical measurements, and evaluation of immunocompetence) were retrospectively reviewed in 74 patients undergoing an initial liver transplantation procedure. The patients were subdivided into four categories on the basis of type of liver disease: chronic active hepatitis (N = 24), primary sclerosing cholangitis (N = 22), primary biliary cirrhosis (N = 20), and acute or subacute hepatitis (N = 8). Our nutritional assessment data indicated that malnutrition was present preoperatively in all liver transplantation groups but that each group had distinct characteristics. The group with primary biliary cirrhosis seemed to have the best hepatic synthetic function despite extreme wasting of muscle and fat. On the basis of all criteria, the group with acute hepatitis was the most malnourished of the various disease groups. Aggressive nutritional support, which includes adequate intake of nutrients and supplementation of vitamins and trace minerals, should be encouraged for all potential liver transplant patients.