Multidrug resistance-associated protein 2 (Mrp2) mediates biliary secretion of anionic endobiotics and xenobiotics. Genetic alteration of Mrp2 leads to conjugated hyperbilirubinemia and predisposes to the development of intrahepatic cholestasis of pregnancy (ICP), characterized by increased plasma bile acids (BAs) due to mechanisms that are incompletely understood. Therefore, this study aimed to characterize BA metabolomics during experimental Mrp2 deficiency and ICP. ICP was modeled by ethinylestradiol (EE) administration to Mrp2-deficient (TR) rats and their wild-type (WT) controls. Spectra of BAs were analyzed in plasma, bile, and stool using an advanced liquid chromatography-mass spectrometry (LC-MS) method. Changes in BA-related genes and proteins were analyzed in the liver and intestine. Vehicle-administered TR rats demonstrated higher plasma BA concentrations consistent with reduced BA biliary secretion and increased BA efflux from hepatocytes to blood via upregulated multidrug resistance-associated protein 3 (Mrp3) and multidrug resistance-associated protein 4 (Mrp4) transporters. TR rats also showed a decrease in intestinal BA reabsorption due to reduced ileal sodium/bile acid cotransporter (Asbt) expression. Analysis of regulatory mechanisms indicated that activation of the hepatic constitutive androstane receptor (CAR)-Nuclear factor erythroid 2-related factor 2 (Nrf2) pathway by accumulating bilirubin may be responsible for changes in BA metabolomics in TR rats. Ethinylestradiol administration to TR rats further increased plasma BA concentrations as a result of reduced BA uptake and increased efflux via reduced Slco1a1 and upregulated Mrp4 transporters. These results demonstrate that Mrp2-deficient organism is more sensitive to estrogen-induced cholestasis. Inherited deficiency in Mrp2 is associated with activation of Mrp3 and Mrp4 proteins, which is further accentuated by increased estrogen. Bile acid monitoring is therefore highly desirable in pregnant women with conjugated hyperbilirubinemia for early detection of intrahepatic cholestasis.

• Klíčová slova
• Mrp2-deficient rats, Nrf2, bile acids, cholestasis, estrogen,
• Publikační typ
• časopisecké články MeSH

Nonalcoholic steatohepatitis (NASH) is characterized by hepatic steatosis with inflammation and fibrosis. Membrane endoglin (Eng) expression is shown to participate in fibrosis, and plasma concentrations of soluble endoglin (sEng) are increased in patients with hypercholesterolemia and type 2 diabetes mellitus. We hypothesize that NASH increases both hepatic Eng expression and sEng in blood and that high levels of sEng modulate cholesterol and bile acid (BA) metabolism and affect NASH progression. Three-month-old transgenic male mice overexpressing human sEng and their wild type littermates are fed for six months with either a high-saturated fat, high-fructose high-cholesterol (FFC) diet or a chow diet. Evaluation of NASH, Liquid chromatography-mass spectrometry (LC/MS) analysis of BA, hepatic expression of Eng, inflammation, fibrosis markers, enzymes and transporters involved in hepatic cholesterol and BA metabolism are assessed using Real-Time Quantitative Reverse Transcription Polymerase Chain reaction (qRT-PCR) and Western blot. The FFC diet significantly increases mouse sEng levels and increases hepatic expression of Eng. High levels of human sEng results in increased hepatic deposition of cholesterol due to reduced conversion into BA, as well as redirects the metabolism of triglycerides (TAG) to its accumulation in the liver, via reduced TAG elimination by β-oxidation combined with reduced hepatic efflux. We propose that sEng might be a biomarker of NASH development, and the presence of high levels of sEng might support NASH aggravation by impairing the essential defensive mechanism protecting NASH liver against excessive TAG and cholesterol accumulation, suggesting the importance of high sEng levels in patients prone to develop NASH.

• Klíčová slova
• FFC diet, NASH, bile acids, bile production, cholesterol, endoglin,
• MeSH
• alkalická fosfatasa metabolismus   MeSH
• aspartátaminotransferasy metabolismus   MeSH
• biologické markery krev   metabolismus   MeSH
• biologické modely MeSH
• cholesterol krev   metabolismus   MeSH
• dieta s vysokým obsahem tuků MeSH
• endoglin krev   metabolismus   MeSH
• fruktosa MeSH
• jaterní cirhóza krev   komplikace   patologie   MeSH
• játra metabolismus   patologie   MeSH
• lidé MeSH
• modely nemocí na zvířatech MeSH
• myši MeSH
• nealkoholová steatóza jater krev   komplikace   metabolismus   MeSH
• oxidační stres MeSH
• rozpustnost MeSH
• triglyceridy metabolismus   MeSH
• zánět patologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• alkalická fosfatasa MeSH
• aspartátaminotransferasy MeSH
• biologické markery MeSH
• cholesterol MeSH
• endoglin MeSH
• fruktosa MeSH
• triglyceridy MeSH

Excessive iron accumulation in the liver, which accompanies certain genetic or metabolic diseases, impairs bile acids (BA) synthesis, but the influence of iron on the complex process of BA homeostasis is unknown. Thus, we evaluated the effect of iron overload (IO) on BA turnover in rats. Compared with control rats, IO (8 intraperitoneal doses of 100 mg/kg every other day) significantly decreased bile flow as a consequence of decreased biliary BA secretion. This decrease was associated with reduced expression of Cyp7a1, the rate limiting enzyme in the conversion of cholesterol to BA, and decreased expression of Bsep, the transporter responsible for BA efflux into bile. However, IO did not change net BA content in faeces in response to increased intestinal conversion of BA into hyodeoxycholic acid. In addition, IO increased plasma cholesterol concentrations, which corresponded with reduced Cyp7a1 expression and increased expression of Hmgcr, the rate-limiting enzyme in de novo cholesterol synthesis. In summary, this study describes the mechanisms impairing synthesis, biliary secretion and intestinal processing of BA during IO. Altered elimination pathways for BA and cholesterol may interfere with the pathophysiology of liver damage accompanying liver diseases with excessive iron deposition.

• MeSH
• biologické markery MeSH
• cholesterol metabolismus   MeSH
• exprese genu MeSH
• játra metabolismus   patologie   MeSH
• krysa rodu Rattus MeSH
• messenger RNA genetika   metabolismus   MeSH
• modely nemocí na zvířatech MeSH
• oxidační stres MeSH
• přetížení železem etiologie   metabolismus   patologie   MeSH
• žlučové kyseliny a soli metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• biologické markery MeSH
• cholesterol MeSH
• messenger RNA MeSH
• žlučové kyseliny a soli MeSH

AIM: To investigate the effect of resveratrol on biliary secretion of cholephilic compounds in healthy and bile duct-obstructed rats. METHODS: Resveratrol (RSV) or saline were administered to rats by daily oral gavage for 28 d after sham operation or reversible bile duct obstruction (BDO). Bile was collected 24 h after the last gavage during an intravenous bolus dose of the Mdr1/Mrp2 substrate azithromycin. Bile acids, glutathione and azithromycin were measured in bile to quantify their level of biliary secretion. Liver expression of enzymes and transporters relevant for bile production and biliary secretion of major bile constituents and drugs were analyzed at the mRNA and protein levels using qRT-PCR and Western blot analysis, respectively. The TR-FRET PXR Competitive Binding Assay kit was used to determine the agonism of RSV at the pregnane X receptor. RESULTS: RSV increased bile flow in sham-operated rats due to increased biliary secretion of bile acids (BA) and glutathione. This effect was accompanied by the induction of the hepatic rate-limiting transporters for bile acids and glutathione, Bsep and Mrp2, respectively. RSV also induced Cyp7a1, an enzyme that is crucial for bile acid synthesis; Mrp4, a transporter important for BA secretion from hepatocytes to blood; and Mdr1, the major apical transporter for xenobiotics. The findings were supported by increased biliary secretion of azithromycin. The TR-FRET PXR competitive binding assay confirmed RSV as a weak agonist of the human nuclear receptor PXR, which is a transcriptional regulator of Mdr1/Mrp2. RSV demonstrated significant hepatoprotective properties against BDO-induced cirrhosis. RSV also reduced bile flow in BDO rats without any corresponding change in the levels of the transporters and enzymes involved in RSV-mediated hepatoprotection. CONCLUSION: Resveratrol administration for 28 d has a distinct effect on bile flow and biliary secretion of cholephilic compounds in healthy and bile duct-obstructed rats.

• Klíčová slova
• Azithromycin, Bile acids, Bile production, Pregnane X receptor, Resveratrol,
• MeSH
• ABC transportéry metabolismus   MeSH
• antiflogistika nesteroidní farmakologie   terapeutické užití   MeSH
• antioxidancia farmakologie   terapeutické užití   MeSH
• aplikace orální MeSH
• azithromycin farmakokinetika   MeSH
• cholestáza farmakoterapie   etiologie   patofyziologie   MeSH
• glutathion metabolismus   MeSH
• hepatocyty účinky léků   metabolismus   MeSH
• játra účinky léků   metabolismus   patofyziologie   MeSH
• krysa rodu Rattus MeSH
• lidé MeSH
• modely nemocí na zvířatech MeSH
• potkani Wistar MeSH
• pregnanový X receptor MeSH
• resveratrol MeSH
• steroidní receptory agonisté   MeSH
• stilbeny farmakologie   terapeutické užití   MeSH
• žlučové kyseliny a soli chemie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• lidé MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• ABC transportéry MeSH
• antiflogistika nesteroidní MeSH
• antioxidancia MeSH
• azithromycin MeSH
• glutathion MeSH
• pregnanový X receptor MeSH
• resveratrol MeSH
• steroidní receptory MeSH
• stilbeny MeSH
• žlučové kyseliny a soli MeSH

BACKGROUND: Two-thirds partial hepatectomy (PHx) is an established model for the study of liver regeneration after resection. This process is accompanied by oxidative stress. AIMS: In our study, we tested the effect of epigallocatechin gallate (EGCG), a green tea antioxidant, on the early phase of liver regeneration after PHx. METHODS: Male Wistar rats were divided into five groups: (I) laparotomy + water for intraperitoneal injections, (II) laparotomy + EGCG 50 mg/kg body weight, (III) PHx + water for injections, (IV) PHx + EGCG 20 mg/kg and (V) PHx + EGCG 50 mg/kg, for 3 consecutive days. The rats were killed 24 h after surgery. Biochemical analysis of rat sera was performed. Histological samples were stained with hematoxylin & eosin and bromodeoxyuridine (BrdU). In hepatectomized rats, we also measured plasma malondialdehyde, tissue malondialdehyde, glutathione and cytokines levels, the activity of caspases 3/7, expression of Nqo-1 and HO-1 genes at the mRNA level, and expression of p21, p-p27 and p-p53 genes at the protein level. RESULTS: We observed lower accumulation of BrdU in group V when compared to groups III and IV. The activity of caspases 3/7 and expression of p-p53 were lower in group V than in groups III and IV. Tissue levels of IL-6 were lower in group V when compared to group III. Significant differences were not noted in other parameters. CONCLUSIONS: Administration of EGCG did not stimulate early phase liver regeneration in rats after PHx. There was even lower DNA synthesis in the group treated with a high dose of EGCG.

• MeSH
• antioxidancia farmakologie   terapeutické užití   MeSH
• cytokiny genetika   metabolismus   MeSH
• hemoxygenasa-1 genetika   metabolismus   MeSH
• hepatektomie metody   MeSH
• kaspasy genetika   metabolismus   MeSH
• katechin analogy a deriváty   farmakologie   terapeutické užití   MeSH
• krysa rodu Rattus MeSH
• messenger RNA genetika   metabolismus   MeSH
• NAD(P)H dehydrogenasa (chinon) genetika   metabolismus   MeSH
• oxidační stres fyziologie   MeSH
• potkani Wistar MeSH
• proteiny buněčného cyklu genetika   metabolismus   MeSH
• regenerace jater účinky léků   MeSH
• regulace genové exprese účinky léků   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antioxidancia MeSH
• cytokiny MeSH
• epigallocatechin gallate MeSH Prohlížeč
• hemoxygenasa-1 MeSH
• kaspasy MeSH
• katechin MeSH
• messenger RNA MeSH
• NAD(P)H dehydrogenasa (chinon) MeSH
• NQO1 protein, rat MeSH Prohlížeč
• proteiny buněčného cyklu MeSH