Biliary atresia: pathology, etiology and pathogenesis

Biliary atresia is a progressive fibrosing obstructive cholangiopathy of the intrahepatic and extrahepatic biliary system, resulting in obstruction of bile flow and neonatal jaundice. Histopathological findings in liver biopsies include the expansion of the portal tracts, with edematous fibroplasia and bile ductular proliferation, with bile plugs in duct lumen. Lobular morphological features may include variable multinucleate giant cells, bilirubinostasis and hemopoiesis. The etiopathogenesis of biliary atresia is multifactorial and multiple pathomechanisms have been proposed. Experimental and clinical studies have suggested that viral infection initiates biliary epithelium destruction and release of antigens that trigger a Th1 immune response, which leads to further injury of the bile duct, resulting in inflammation and obstructive scarring of the biliary tree. It has also been postulated that biliary atresia is caused by a defect in the normal remodelling process. Genetic predisposition has also been proposed as a factor for the development of biliary atresia.

Non-clinical safety evaluation of a novel pharmaceutical salt, rosuvastatin ethanolamine, in Wistar rats

Rosuvastatin, a second generation 3-Hydroxy-3-Methyl Glutaryl Coenzyme-A reductase inhibitor, is widely used for the management of hypercholesterolemia. Rosuvastatin ethanolamine, developed by Cadila Healthcare Ltd., is a novel, chemically stable, and pharmaceutically acceptable salt, having better physiochemical properties than commercially available Rosuvastatin salt. The objective of the present study is to evaluate safety, tolerability, and toxicokinetic profile of novel salt. Therefore, four weeks repeated dose oral (gavage) toxicity and toxicokinetic study of Rosuvastatin ethanolamine was carried out. The drugs were administered once daily at salt corrected dose of 15, 40, and 100 mg/kg for four weeks. No signs of toxicity were observed during repeated (four weeks) oral administrations of Rosuvastatin ethanolamine in rats up to 40 mg/kg. Single male mortality was observed at 100 mg/kg dose. Microscopy finding in liver was minimal to mild bile ductular proliferation, single cell necrosis, and hepatocellular vacuolation of cytoplasm with associated statistically significant serum elevation of transaminase enzymes; AST, ALT, ALP, and/or liver functional marker; total bilirubin with at ≥40 mg/kg. The systemic exposures (AUC0–24 and Cmax) were not markedly different between males and females, or between the administration periods (except high dose, where exposure on day 28 was approximately 2 to 3 fold higher than that of day 1. In conclusion, Rosuvastatin ethanolamine exhibited toxicities to liver as the target organ at ≥40 mg/kg in this study. These adverse effects with associated exposures should be taken into consideration for the future assessing of potential Rosuvastatin toxicities.

iPla2β Deficiency Suppresses Hepatic ER UPR, Fxr, and Phospholipids in Mice Fed with MCD Diet, Resulting in Exacerbated Hepatic Bile Acids and Biliary Cell Proliferation

Background: Group VIA calcium-independent phospholipase A2 (iPla2β) regulates homeostasis and remodeling of phospholipids (PL). We previously showed that iPla2β−/− mice fed with a methionine-choline-deficient diet (MCD) exhibited exaggerated liver fibrosis. As iPla2β is located in the endoplasmic reticulum (ER), we investigated the mechanisms for this by focusing on hepatic ER unfolded protein response (UPR), ER PL, and enterohepatic bile acids (BA). Methods: Female WT (wild-type) and iPla2β−/− mice were fed with chow or MCD for 5 weeks. PL and BA profiles were measured by liquid chromatography-mass spectrometry. Gene expression analyses were performed. Results: MCD feeding of WT mice caused a decrease of ER PL subclasses, which were further decreased by iPla2β deficiency. This deficiency alone or combined with MCD downregulated the expression of liver ER UPR proteins and farnesoid X-activated receptor. The downregulation under MCD was concomitant with an elevation of BA in the liver and peripheral blood and an increase of biliary epithelial cell proliferation measured by cytokeratin 19. Conclusion: iPla2β deficiency combined with MCD severely disturbed ER PL composition and caused inactivation of UPR, leading to downregulated Fxr, exacerbated BA, and ductular proliferation. Our study provides insights into iPla2β inactivation for injury susceptibility under normal conditions and liver fibrosis and cholangiopathies during MCD feeding.

Copper deposition in focal nodular hyperplasia and inflammatory hepatocellular adenoma

AimsTo examine copper deposition in focal nodular hyperplasia (FNH) and inflammatory hepatocellular adenoma (IHA) and to determine if it can play a role in their differentiation.Methods28 FNHs and 19 IHAs from surgical resections showing typical morphological and immunohistochemical features were stained with rhodanine to evaluate for copper deposition. Histological features such as nodularity, fibrous bands, ductular proliferation, steatosis, ballooned hepatocytes and lymphocytic inflammation were also scored.ResultsCopper deposition was detected in 96% (27/28) of FNHs and 37% (7/19) of IHAs, P<0.001. In all cases, copper was seen within the hepatocytes only around the pseudo-portal tracts or areas of fibrosis. Copper deposition in IHA was significantly associated with presence of lymphocytic inflammation (P=0.04) but not associated with features like nodularity, fibrous bands, ductular proliferation, ballooned hepatocytes and steatosis (P>0.05, for all). In FNH, the presence and degree of copper deposition was not significantly associated with any histological features (P>0.05, for all).ConclusionsCopper deposition occurs more frequently in FNH (96%) than IHA (37%), P<0.001. However, the presence of copper alone cannot be used as a feature to differentiate between FNH and IHA.

Steatohepatitis in laboratory opossums exhibiting a high lipemic response to dietary cholesterol and fat

Plasma VLDL and LDL cholesterol were markedly elevated (>40-fold) in high-responding opossums, but moderately elevated (6-fold) in low-responding opossums after they had consumed a high-cholesterol and high-fat diet for 24 wk. In both high- and low-responding opossums, plasma triglycerides were slightly elevated, threefold and twofold, respectively. Dietary challenge also induced fatty livers in high responders, but not in low responders. We studied the lipid composition, histopathological features, and gene expression patterns of the fatty livers. Free cholesterol (2-fold), esterified cholesterol (11-fold), and triglycerides (2-fold) were higher in the livers of high responders than those in low responders, whereas free fatty acid levels were similar. The fatty livers of high responders showed extensive lobular disarray by histology. Inflammatory cells and ballooned hepatocytes were also present, as were perisinusoidal fibrosis and ductular proliferation. In contrast, liver histology was normal in low responders. Hepatic gene expression revealed differences associated with the development of steatohepatitis in high responders. The accumulation of hepatic cholesterol was concomitant with upregulation of the HMGCR gene and downregulation of the CYP27A1, ABCG8, and ABCB4 genes. Genes involved in inflammation ( TNF, NFKB1, and COX2) and in oxidative stress ( CYBA and NCF1) were upregulated. Upregulation of the growth factor genes ( PDGF and TGFB1) and collagen genes ( Col1A1, Col3A1, and Col4A1) was consistent with fibrosis. Some of the histological characteristics of the fatty livers of high-responding opossums imitate those in the livers of humans with nonalcoholic steatohepatitis.

Gadolinium chloride, a Kupffer cell inhibitor, attenuates hepatic injury in a rat model of chronic cholestasis

The aim of the current study was to elucidate the effect of Kupffer cells inhibition on hepatic injury induced by chronic cholestasis. Sprague-Dawley rats underwent bile duct ligation (BDL) or sham operation and were treated with either saline solution or gadolinium chloride (GdCl3, a specific Kupffer cell inhibitor, 20 mg/kg i.p. daily). Serum and liver samples were collected after 28 days. Direct and total bilirubin concentrations and serum enzyme activities of alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and γ-glutamyl transpeptidase (GGT) increased following BDL ( p < 0.01). On the contrary to bilirubin concentrations and AST activity, GdCl3 partially prevented the elevation in ALP, ALT and GGT enzyme activities ( p < 0.05). GdCl3 alleviated lipid peroxidation (reflected by malondialdehyde [MDA] concentration) and increased the activities of antioxidant enzymes (i.e. catalase and glutathione peroxidase) in liver samples after BDL ( p < 0.05). Fibrosis, ductular proliferation and portal inflammation were also scored in liver samples. Among morphological changes appeared following BDL (i.e. marked fibrosis, portal inflammation and ductular proliferation); only ductular proliferation was not alleviated by GdCl3. Therefore, Kupffer cells inhibition has beneficial effects against the development of hepatic injury induced by chronic cholestasis.