Induction of chronic cholestasis without liver cirrhosis-Creation of an animal model

To analyze time intervals of inflammation and regeneration in a cholestatic rat liver model.METHODSIn 36 Lewis rats, divided into six groups of 6 animals (postoperative observation periods: 1, 2, 3, 4, 6, 8 wk), the main bile duct was ligated with two ligatures and observed for the periods mentioned above. For laboratory evaluation, cholestasis parameters (bilirubin, γ-GT), liver cell parameters (ASAT, ALAT) and liver synthesis parameters (quick, albumin) were determined. For histological analysis, HE, EvG, ASDCL and HMGB-1 stainings were performed. Furthermore, we used the mRNA of IL-33, GADD45a and p-21 for analyzing cellular stress and regeneration in cholestatic rats.RESULTSIn chemical laboratory and histological evaluation, a distinction between acute and chronic cholestatic liver injury with identification of inflammation and regeneration could be demonstrated by an increase in cholestasis (bilirubin: 1-wk group, 156.83 ± 34.12 μmol/L, P = 0.004) and liver cell parameters (ASAT: 2-wk group, 2.1 ± 2.19 μmol/L.s, P = 0.03; ALAT: 2-wk group, 1.03 ± 0.38 μmol/L.s, P = 0.03) after bile duct ligation (BDL). Histological evaluation showed an increase of bile ducts per portal field (3-wk group, 48 ± 6.13, P = 0.004) during the first four weeks after bile duct ligation. In addition to inflammation, which is an expression of acute cholestasis, there was an increase of necrotic areas in the histological sections (2-wk group, 1.38% ± 2.28% per slide, P = 0.002). Furthermore, the inflammation could be verified by ASDCL (4-wk group, 22 ± 5.93 positive cells per portal field, P = 0.041) and HMGB-1 [2-wk group, 13 ± 8.18 positive cells per field of view (FoV), P = 0.065] staining. Therefore, in summary of the laboratory evaluation and histological studies, acute cholestasis could be found during the first four weeks after bile duct ligation. Subsequently, the described parameters declined so that chronic cholestasis could be assumed. For quantification of secondary biliary cirrhosis, eosin staining was performed, which did not reveal any signs of liver remodeling, thus precluding the development of a chronic cholestasis model. Additionally, to establish the chronic cholestasis model, we evaluated liver regeneration capacity through measurements of IL-33, p-21 and GADD45a mRNA.CONCLUSIONWe created a chronic cholestasis model. The point of inflammatory and regenerative balance was reached after four weeks. This finding should be used for experimental approaches dealing with chronic cholestatic liver damage.

Pathogenic role of oxidative and nitrosative stress in primary biliary cirrhosis

Primary biliary cirrhosis is a multifactor autoimmune disease characterized by hepatic and systemic manifestations,with immune system dysregulation and abnormalities in the hepatic metabolism of bile salts,lipids,and nutrients,as well as destruction of membrane lipids and mitochondrial dysfunction.Both oxidative and nitrosative stress are associated with ongoing manifestations of the disease.In particular,abnormalities in nitric oxide metabolism and thiol oxidation already occur at early stages,thus leading to the hypothesis that these biochemical events play a pathogenic role in primary biliary cirrhosis.Moreover,the association of these metabolic abnormalities with the progression of the disease may indicate some biochemical parameters as early diagnostic markers of disease evolution,and may open up the potential for pharmacological intervention to inhibit intra-and extra-cellular stress events for resuming hepatocellular functions.The following paragraphs summarize the current knowledge by outlining molecular mechanisms of the disease related to these stress events.

Heme oxygenase-1 overexpression increases liver injury after bile duct ligation in rats

AIM： To investigate the effects of heme oxygenase-1 （HO-1） against oxidant-induced injury caused by bile duct ligation （BDL）.METHODS： Either cobalt protoporphyrin （CoPP）, a HO-1 inducer, or saline were injected intraperitoneally in male SD-rats. Three days later, BDL or sham-operations were performed. Rats were sacrificed 3 wk after BDL and livers were harvested for histology. Fibrosis was evaluated by sirius red staining and image analysis. Alpha-smooth muscular actin, which indicates activation of stellate cells, was detected by immunohistochemical staining, and q/tokine and collagen- Iα （Col- I α） mRNA expression was detected using RNase protection assays.RESULTS： Serum alanine transaminase increased 8-fold above normal levels one day after BDL. Surprisingly, enzyme release was not reduced in rats receiving CoPP. Liver fibrosis was evaluated 3 wk after BDL and the sirius red-positive area was found to be increased to about 7.8%. However, in CoPP pretreated rats sirius redpositive areas were increased to about 11.7% after BDL. Collagen-1 α and TGF-β mRNA increased significantly by BDL. Again, this effect was increased by HO-1 overexpression.CONCLUSION： Hepatic fibrosis due to BDL is not reduced by the HO-1 inducer CoPP. In contrast, HO-1 overexpression increases liver injury in rats under conditions of experimental chronic cholestasis.

Heritable Chronic Cholestatic Liver Diseases:A Review

Chronic cholestasis due to heritable causes is usually diagnosedin childhood.However,many cases can present andsurvive into adulthood.The time course varies considerablydepending on the underlying etiology.Laboratory data usuallyreveal elevated conjugated hyperbilirubinemia,alkalinephosphatase,and gamma-glutamyl transpeptidase.Patientsmay be asymptomatic;however,when present,the typicalsymptoms are pruritus,jaundice,fatigue,and alcoholicstools.The diagnostic methods and management requireddepend on the underlying etiology.The development of genome-wide associated studies has allowed the identificationof specific genetic mutations related to the pathophysiologyof cholestatic liver diseases.The aim of this review was tohighlight the genetics,clinical pathophysiology,presentation,diagnosis,and treatment of heritable etiologies of chroniccholestatic liver disease.