Cellular mechanisms of intrahepatic cholestasis

The IDI1/SREBP2 axis drives intrahepatic cholestasis and is a treatment target of San-Huang-Cai-Zhu formula identified by sequencing and experiments

San-Huang-Chai-Zhu formula (SHCZF), originates from Da-Huang-Xiao-Shi decoction (DHXSD) for the treatment of jaundice as recorded in the Chinese traditional Chinese medicine book Jin Gui Yao Lue. In the clinic, SHCZF has been used to treat cholestasis-related liver disease by improving intrahepatic cholestasis, but the treatment mechanism has not been elucidated. In this study, 24 Sprague-Dawley (SD) rats were randomly assigned to the normal, acute intrahepatic cholestasis (AIC), SHCZF, and ursodeoxycholic acid (UDCA) groups. In addition, 36 SD rats were divided into dynamic groups, namely, normal 24 h, AIC 24 h, normal 48 h, AIC 48 h, normal 72 h, and AIC 72 h groups. Alpha-naphthylisothiocyanate (ANIT) was used to induce an AIC rat model. Serum biochemical indices and hepatic pathology were detected. Part of the hepatic tissues was used for sequencing, and others were used for subsequent experiments. Sequencing data combined with bioinformatics analysis were used to screen target genes and identify the mechanisms of SHCZF in treating AIC rats. Quantitative real-time PCR (qRT-PCR) and Western blotting (WB) were used to detect the RNA/Protein expression levels of screened genes. Rats in the dynamic group were used to determine the sequence of cholestasis and liver injury. High-performance liquid chromatography (HPLC) was used to determine the representative bioingredients of SHCZF. Sequencing and bioinformatics analysis suggested that IDI1 and SREBP2 are hub target genes of SHCZF to ameliorate ANTI-induced intrahepatic cholestasis in rats. The treatment mechanism is associated with the regulation of lipoprotein receptor (LDLr) to reduce cholesterol intake and 3-Hydroxy-3-Methylglutaryl-CoA reductase (HMGCR), and 3-Hydroxy-3-Methylglutaryl-CoA synthase 1 (HMGCS1) to decrease cholesterol synthesis. Animal experiments showed that SHCZF significantly reduced the expression levels of the above genes and proinflammatory cytokine lipocalin 2 (LCN2), inflammatory cytokines interleukin 1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α), thereby improving intrahepatic cholestasis and inflammation and liver injury.

Resolution of danazol-induced cholestasis with S-adenosylmethionine

In a case of danazol-induced cholestasis, the anti-cholestatic agent S-adenosylmethionine was given intravenously for 3 weeks and then orally for 6 weeks. This was well tolerated and led to prompt resolution of both jaundice and associated renal impairment.

Atrial natriuretic factor modifies bile flow and composition in the rat

The effects of atrial natriuretic factor (ANF) on bile secretion were studied in the rat. ANF was injected 'in bolus' (5.0 micrograms/kg) every 30 min into the jugular vein. The common bile duct was cannulated and bile samples were collected every 30 min for 120 min. Systemic blood arterial pressure was registered before and after the administration of ANF. Results showed that ANF decreased bile flow and the excretion rate of sodium, potassium, chloride, bile acids, cholesterol and proteins. On the other hand, it increased pH and the excretion of bicarbonate and calcium. As ANF slightly reduces mean arterial pressure, its vascular effect may not be considered the major event. In addition, increased excretion of bicarbonate and calcium, and the fact that ANF vascular effect is short in time suggest that the peptide may have a non-vascular effect on the processes of bile formation and its modifications along the bile ducts. This extravascular effect may be exerted on the hepatocyte ions exchangers and/or at the ductal level on the processes of excretion and reabsorption of electrolytes and water.

Effect of bile acids on intracellular calcium in isolated rat hepatocyte couplets

The effects of bile acids on cytosolic free calcium ([Ca2+]i) were studied in single isolated rat hepatocyte couplets using a scanning laser cytometer and the fluorescent dye, indo-1. Cholestatic bile acids, chenodeoxycholate (CDC) and taurolithocholate (TLC) increased [Ca2+]i in a dose-dependent manner. Choleretic bile acids, tauroursodeoxycholate (TUDC) and taurocholate (TC), did not induce any change in [Ca2+]i except TC at very high doses. Treatment with TUDC added concomitantly with CDC or TLC significantly decreased the rise in [Ca2+]i induced by bile acids. These results, obtained with a polarized hepatocyte model that secretes bile, confirmed that cholestatic bile acids increase [Ca2+]i and showed that TUDC inhibits this phenomenon. These data are in agreement with a key role of intracellular calcium in cholestasis.

Actin filament alteration as a potential marker for cholestasis: a study in isolated rat hepatocyte couplets

It has been suggested that modification of the pericanalicular microfilament network (F-actin) plays a role in cholestasis. The purposes of this study were to assess (i) the process of F-actin network reorganization in isolated rat hepatocyte couplets (IRHC) in order to define the optimal study conditions in this model, (ii) the effect of cholestatic and hepatotoxic but non-cholestatic compounds on F-actin distribution in IRHC. F-actin was stained with fluorescein isothiocyanate phalloidin and fluorimetric measurements were performed in single couplets using a scanning laser cytometer, ACAS 570. F-actin distribution was assessed by the ratio of canalicular area fluorescence/total couplet fluorescence (CF/TF). The organization of the F-actin filaments was restored in IRHC 3-6 h after plating. At non-cytotoxic concentrations, most cholestatic compounds induced a significant accumulation of F-actin around the bile canaliculus as indicated by increased fluorescence in the pericanalicular area and by the increased CF/TF ratio as compared to the controls. This accumulation could be a consequence of an inhibition of F-actin depolymerization or a higher organization of actin (redistribution, bundling or reorientation). Hepatotoxic but non-cholestatic compounds did not induce any change in pericanalicular F-actin. Abnormalities of pericanalicular F-actin therefore appear to be a specific marker of hepatocellular cholestasis.