Decreased inflammatory status has been reported in subjects with mild unconjugated hyperbilirubinemia. However, mechanisms of the anti-inflammatory actions of bilirubin (BR) are not fully understood. The aim of this study is to assess the role of BR in systemic inflammation using hyperbilirubinemic Gunn rats as well as their normobilirubinemic littermates and further in primary hepatocytes. The rats were treated with lipopolysaccharide (LPS, 6 mg/kg intraperitoneally) for 12 h, their blood and liver were collected for analyses of inflammatory and hepatic injury markers. Primary hepatocytes were treated with BR and TNF-α. LPS-treated Gunn rats had a significantly decreased inflammatory response, as evidenced by the anti-inflammatory profile of white blood cell subsets, and lower hepatic and systemic expressions of IL-6, TNF-α, IL-1β, and IL-10. Hepatic mRNA expression of LPS-binding protein was upregulated in Gunn rats before and after LPS treatment. In addition, liver injury markers were lower in Gunn rats as compared to in LPS-treated controls. The exposure of primary hepatocytes to TNF-α with BR led to a milder decrease in phosphorylation of the NF-κB p65 subunit compared to in cells without BR. In conclusion, hyperbilirubinemia in Gunn rats is associated with an attenuated systemic inflammatory response and decreased liver damage upon exposure to LPS.

• MeSH
• apoptóza účinky léků   MeSH
• bilirubin farmakologie   MeSH
• biologické markery krev   MeSH
• cytokiny krev   genetika   metabolismus   MeSH
• cytoprotekce účinky léků   MeSH
• fosforylace účinky léků   MeSH
• hepatocyty metabolismus   MeSH
• hyperbilirubinemie krev   komplikace   MeSH
• játra metabolismus   MeSH
• kultivované buňky MeSH
• leukocyty metabolismus   MeSH
• lipopolysacharidy MeSH
• messenger RNA genetika   metabolismus   MeSH
• NF-kappa B metabolismus   MeSH
• potkani Gunn MeSH
• signální transdukce MeSH
• zánět komplikace   MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Unconjugated hyperbilirubinemia, a feature of neonatal jaundice or Crigler-Najjar syndrome, can lead to neurotoxicity and even death. We previously demonstrated that unconjugated bilirubin (UCB) can be eliminated via transintestinal excretion in Gunn rats, a model of unconjugated hyperbilirubinemia, and that this is stimulated by enhancing fecal fatty acid excretion. Since transintestinal excretion also occurs for cholesterol (TICE), we hypothesized that increasing fecal cholesterol excretion and/or TICE could also enhance fecal UCB disposal and subsequently lower plasma UCB concentrations. METHODS: To determine whether increasing fecal cholesterol excretion could ameliorate unconjugated hyperbilirubinemia, we treated hyperbilirubinemic Gunn rats with ezetimibe (EZE), an intestinal cholesterol absorption inhibitor, and/or a liver X receptor (LXR) and farnesoid X receptor (FXR) agonist (T0901317 (T09) and obeticholic acid (OCA), respectively), known to stimulate TICE. RESULTS: We found that EZE treatment alone or in combination with T09 or OCA increased fecal cholesterol disposal but did not lower plasma UCB levels. CONCLUSIONS: These findings do not support a link between the regulation of transintestinal excretion of cholesterol and bilirubin. Furthermore, induction of fecal cholesterol excretion is not a potential therapy for unconjugated hyperbilirubinemia. IMPACT: Increasing fecal cholesterol excretion is not effective to treat unconjugated hyperbilirubinemia. This is the first time a potential relation between transintestinal excretion of cholesterol and unconjugated bilirubin is investigated. Transintestinal excretion of cholesterol and unconjugated bilirubin do not seem to be quantitatively linked. Unlike intestinal fatty acids, cholesterol cannot "capture" unconjugated bilirubin to increase its excretion. These results add to our understanding of ways to improve and factors regulating unconjugated bilirubin disposal in hyperbilirubinemic conditions.

• MeSH
• bilirubin chemie   MeSH
• cholesterol metabolismus   MeSH
• Criglerův-Najjarův syndrom metabolismus   terapie   MeSH
• dietní tuky farmakokinetika   MeSH
• ezetimib farmakologie   terapeutické užití   MeSH
• feces chemie   MeSH
• fluorované uhlovodíky farmakologie   terapeutické užití   MeSH
• haptoglobiny analýza   MeSH
• hyperbilirubinemie terapie   MeSH
• jaterní receptor X metabolismus   MeSH
• krysa rodu rattus MeSH
• kyselina chenodeoxycholová analogy a deriváty   farmakologie   terapeutické užití   MeSH
• lipidy krev   MeSH
• náhodné rozdělení MeSH
• potkani Gunn MeSH
• PPAR delta metabolismus   MeSH
• receptory cytoplazmatické a nukleární metabolismus   MeSH
• střeva účinky léků   metabolismus   MeSH
• sulfonamidy farmakologie   terapeutické užití   MeSH
• žluč chemie   MeSH
• žlučové kyseliny a soli metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Background: Circulating bilirubin is associated with reduced adiposity in human and animal studies. A possible explanation is provided by in vitro data that demonstrates that bilirubin inhibits mitochondrial function and decreases efficient energy production. However, it remains unclear whether hyperbilirubinemic animals have similar perturbed mitochondrial function and whether this is important for regulation of energy homeostasis. Aim: To investigate the impact of unconjugated hyperbilirubinemia on body composition, and mitochondrial function in hepatic tissue and skeletal muscle. Materials and Methods: 1) Food intake and bodyweight gain of 14-week old hyperbilirubinemic Gunn (n = 19) and normobilirubinemic littermate (control; n = 19) rats were measured over a 17-day period. 2) Body composition was determined using dual-energy X-ray absorptiometry and by measuring organ and skeletal muscle masses. 3) Mitochondrial function was assessed using high-resolution respirometry of homogenized liver and intact permeabilized extensor digitorum longus and soleus fibers. 4) Liver tissue was flash frozen for later gene (qPCR), protein (Western Blot and citrate synthase activity) and lipid analysis. Results: Female hyperbilirubinemic rats had significantly reduced fat mass (Gunn: 9.94 ± 5.35 vs. Control: 16.6 ± 6.90 g, p < 0.05) and hepatic triglyceride concentration (Gunn: 2.39 ± 0.92 vs. Control: 4.65 ± 1.67 mg g-1, p < 0.01) compared to normobilirubinemic controls. Furthermore, hyperbilirubinemic rats consumed fewer calories daily (p < 0.01) and were less energetically efficient (Gunn: 8.09 ± 5.75 vs. Control: 14.9 ± 5.10 g bodyweight kcal-1, p < 0.05). Hepatic mitochondria of hyperbilirubinemic rats demonstrated increased flux control ratio (FCR) via complex I and II (CI+II) (Gunn: 0.78 ± 0.16 vs. Control: 0.62 ± 0.09, p < 0.05). Similarly, exogenous addition of 31.3 or 62.5 μM unconjugated bilirubin to control liver homogenates significantly increased CI+II FCR (p < 0.05). Hepatic PGC-1α gene expression was significantly increased in hyperbilirubinemic females while FGF21 and ACOX1 was significantly greater in male hyperbilirubinemic rats (p < 0.05). Finally, hepatic mitochondrial complex IV subunit 1 protein expression was significantly increased in female hyperbilirubinemic rats (p < 0.01). Conclusions: This is the first study to comprehensively assess body composition, fat metabolism, and mitochondrial function in hyperbilirubinemic rats. Our findings show that hyperbilirubinemia is associated with reduced fat mass, and increased hepatic mitochondrial biogenesis, specifically in female animals, suggesting a dual role of elevated bilirubin and reduced UGT1A1 function on adiposity and body composition.

• Publikační typ
• časopisecké články MeSH

Mild constitutive hyperbilirubinemia is associated with a reduced risk of cardiovascular diseases, diabetes, and cancer. Since these pathologies are associated with aging, inflammation, and oxidative stress, we investigated whether hyperbilirubinemia interferes with ROS homeostasis in cell cultures and with inflammation, senescence, and mitochondrial dysfunction in aged rats. Human embryonic kidney cells and rat primary fibroblasts showed a dose-dependent decrease in the ratio of oxidized/reduced glutathione, intracellular H2O2 levels, and mitochondrial ROS production, with increasing bilirubin concentrations in the culture media. Compared to their normobilirubinemic siblings, aged hyperbilirubinemic Gunn rats showed significantly smaller amounts of visceral fat, better glucose tolerance, and decreased serum levels of proinflammatory cytokines TNFα, IL-1β, and IL-18. Simultaneously, livers from Gunn rats showed decreased expression of senescence markers and cell cycle inhibitors p21 and p16. Mitochondria from aged Gunn rats showed higher respiration and lower H2O2 production compared to controls. In conclusion, we demonstrated that mildly elevated serum bilirubin is generally associated with attenuation of oxidative stress and with better anthropometric parameters, decreased inflammatory status, increased glucose tolerance, fewer signs of cellular senescence, and enhanced mitochondrial function in aged rats.

• MeSH
• bilirubin krev   MeSH
• fibroblasty metabolismus   patologie   MeSH
• hyperbilirubinemie krev   patologie   MeSH
• intracelulární prostor metabolismus   MeSH
• kultivované buňky MeSH
• metabolické nemoci komplikace   patologie   MeSH
• mitochondrie metabolismus   MeSH
• potkani Gunn MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• stárnutí patologie   MeSH
• zánět komplikace   patologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• hyperbilirubinemie MeSH
• potkani Gunn MeSH
• světlo MeSH
• techniky in vitro MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH

• MeSH
• digitonin farmakologie   MeSH
• glukosyltransferasy účinky léků   MeSH
• potkani Gunn MeSH
• proteiny fyziologie   účinky léků   MeSH
• žloutenka farmakoterapie   patofyziologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH

Unconjugated bilirubin (UCB) exhibits potent antioxidant and cytoprotective properties, but causes apoptosis and cytotoxicity at pathologically elevated concentrations. Accurate measurement of UCB concentrations in cells, fluids and tissues is needed to evaluate its role in redox regulation, prevention of atherosclerotic and malignant diseases, and bilirubin encephalopathy. In the present study, we developed and validated a highly sensitive method for tissue UCB determinations. UCB was extracted from rat organs with chloroform/methanol/hexane at pH 6.2 and then partitioned into a minute volume of alkaline buffer that was subjected to HPLC using an octyl reverse phase (RP) column. Addition of mesobilirubin as an internal standard corrected for losses of UCB during extraction. Recoveries averaged 75+/-5%. The detection limit was 10pmol UCB/g wet tissue. Variance was +/-2.5%. When used to measure UCB concentrations in tissues of jaundiced Gunn rats, this procedure yielded UCB levels directly comparable to published methods, and accurately determined very low tissue bilirubin concentrations (

• MeSH
• bilirubin analýza   MeSH
• financování organizované MeSH
• játra chemie   MeSH
• krysa rodu rattus MeSH
• potkani Gunn MeSH
• referenční standardy MeSH
• reprodukovatelnost výsledků MeSH
• senzitivita a specificita MeSH
• tělesné tekutiny chemie   MeSH
• vysokoúčinná kapalinová chromatografie metody   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• validační studie MeSH

High plasma concentrations of bile acids (BA) and bilirubin are hallmarks of cholestasis. BA are implicated in the pathogenesis of cholestatic liver damage through mechanisms involving oxidative stress, whereas bilirubin is a strong antioxidant. We evaluated the roles of bilirubin and BA on mediating oxidative stress in rats following bile duct ligation (BDL). Adult female Wistar and Gunn rats intraperitoneally anaesthetized with ketamine and xylazine underwent BDL or sham operation. Cholestatic markers, antioxidant capacity, lipid peroxidation and heme oxygenase (HO) activity were determined in plasma and/or liver tissue 5 days after surgery. HepG2-rNtcp cells were used for in vitro experiments. Plasma bilirubin levels in control and BDL animals positively correlated with plasma antioxidant capacity. Peroxyl radical scavenging capacity was significantly higher in the plasma of BDL Wistar rats (210 ± 12%, P < 0.0001) compared to controls, but not in the liver tissues. Furthermore after BDL, lipid peroxidation in the livers increased (179 ± 37%, P < 0.01), whereas liver HO activity significantly decreased to 61% of control levels (P < 0.001). Addition of taurocholic acid (TCA, ≥ 50 μmol/l) to liver homogenates increased lipid peroxidation (P < 0.01) in Wistar, but not in Gunn rats or after the addition of bilirubin. In HepG2-rNtcp cells, TCA decreased both HO activity and intracellular bilirubin levels. We conclude that even though plasma bilirubin is a marker of cholestasis and hepatocyte dysfunction, it is also an endogenous antioxidant, which may counteract the pro-oxidative effects of BA in circulation. However, in an animal model of obstructive cholestasis, we found that BA compromise intracellular bilirubin levels making hepatocytes more susceptible to oxidative damage.

• MeSH
• bilirubin metabolismus   MeSH
• cholestáza metabolismus   patologie   MeSH
• hemová oxygenasa (decyklizující) krev   MeSH
• intracelulární prostor metabolismus   MeSH
• játra metabolismus   patologie   MeSH
• krysa rodu rattus MeSH
• kyselina taurocholová farmakologie   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• oxidační stres účinky léků   MeSH
• peroxidace lipidů účinky léků   MeSH
• potkani Gunn MeSH
• potkani Wistar MeSH
• žlučové kyseliny a soli metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Neonatal hyperbilirubinemia or jaundice is associated with kernicterus, resulting in permanent neurological damage or even death. Conventional phototherapy does not prevent hyperbilirubinemia or eliminate the need for exchange transfusion. Here we investigated the potential of therapeutic bile acids ursodeoxycholic acid (UDCA) and obeticholic acid (OCA, 6-α-ethyl-CDCA), a farnesoid-X-receptor (FXR) agonist, as preventive treatment options for neonatal hyperbilirubinemia using the hUGT1*1 humanized mice and Ugt1a-deficient Gunn rats. Treatment of hUGT1*1 mice with UDCA or OCA at postnatal days 10-14 effectively decreased bilirubin in plasma (by 82% and 62%) and brain (by 72% and 69%), respectively. Mechanistically, our findings indicate that these effects are mediated through induction of protein levels of hUGT1A1 in the intestine, but not in liver. We further demonstrate that in Ugt1a-deficient Gunn rats, UDCA but not OCA significantly decreases plasma bilirubin, indicating that at least some of the hypobilirubinemic effects of UDCA are independent of UGT1A1. Finally, using the synthetic, non-bile acid, FXR-agonist GW4064, we show that some of these effects are mediated through direct or indirect activation of FXR. Together, our study shows that therapeutic bile acids UDCA and OCA effectively reduce both plasma and brain bilirubin, highlighting their potential in the treatment of neonatal hyperbilirubinemia.

• MeSH
• bilirubin krev   MeSH
• ileum účinky léků   metabolismus   MeSH
• isoxazoly farmakologie   MeSH
• játra účinky léků   metabolismus   MeSH
• kyselina chenodeoxycholová analogy a deriváty   terapeutické užití   MeSH
• kyselina ursodeoxycholová terapeutické užití   MeSH
• myši MeSH
• novorozenecká hyperbilirubinemie krev   farmakoterapie   MeSH
• potkani Gunn MeSH
• receptory cytoplazmatické a nukleární agonisté   metabolismus   MeSH
• výsledek terapie MeSH
• žlučové kyseliny a soli terapeutické užití   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• Klíčová slova
• protizánětlivý účinek,
• MeSH
• bilirubin * analýza   farmakologie   MeSH
• fosforylace MeSH
• hepatocyty fyziologie   MeSH
• lidé MeSH
• lipopolysacharidy terapeutické užití   MeSH
• modely u zvířat MeSH
• potkani Gunn MeSH
• TNF-alfa analýza   MeSH
• viabilita buněk MeSH
• zánět * farmakoterapie   prevence a kontrola   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• abstrakt z konference MeSH
• práce podpořená grantem MeSH