AIM: To determine whether the promoter polymorphism -203A>C of cholesterol-7α-hydroxylase encoding gene (CYP7A1) affects diurnal variation in CYP7A1 enzyme activity. METHODS: The study included 16 healthy male volunteers - 8 homozygous for -203A and 8 homozygous for the -203C allele of CYP7A1. Three 15-hour examinations (from 7am to 10pm) were carried out for each of the participants: after one-day treatment with cholestyramine; after one-day treatment with chenodeoxycholic acid (CDCA); and a control examination without any treatment. The plasma concentration of 7α-hydroxy-4-cholesten-3-one (C4), a marker of CYP7A1 activity, was determined in all the experiments at 90-min intervals. RESULTS: CYP7A1 activity was up-regulated after treatment with cholestyramine and suppressed after treatment with CDCA. There were no differences between -203A and -203C allele carriers in the response of enzyme activity to both drugs. In the control experiment, -203A allele carriers displayed diurnal variation in enzyme activity, whereas CYP7A1 activity did not change in -203C allele carriers. These results were confirmed by modeling the dynamics of C4 using polynomial regression. CONCLUSION: The promoter polymorphism of the CYP7A1 gene has a pronounced impact on diurnal variation in CYP7A1 activity.

• MeSH
• aktivace enzymů MeSH
• cholestenony krev   MeSH
• cholesterol-7-alfa-hydroxylasa genetika   metabolismus   MeSH
• cholesterol krev   MeSH
• cirkadiánní rytmus fyziologie   MeSH
• dospělí MeSH
• lidé MeSH
• plocha pod křivkou MeSH
• polymorfismus genetický * MeSH
• promotorové oblasti (genetika) MeSH
• upregulace MeSH
• žlučové kyseliny a soli biosyntéza   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 7 alpha-hydroxy-4-cholesten-3-one MeSH Prohlížeč
• cholestenony MeSH
• cholesterol-7-alfa-hydroxylasa MeSH
• cholesterol MeSH
• CYP7A1 protein, human MeSH Prohlížeč
• žlučové kyseliny a soli MeSH

Cholesterol 7alpha-hydroxylase (CYP7A1), the key regulatory enzyme of bile acid synthesis, displays a pronounced diurnal variation. To better understand the regulation of CYP7A1 activity, three day-long examinations were carried out in 12 healthy men. The concentrations of 7alpha-hydroxycholest-4-en-3-one (C4), a surrogate marker of CYP7A1 activity, bile acids (BA), insulin, glucose, nonesterified fatty acids, triglycerides, and cholesterol were measured in serum in 90-min intervals from 7 AM till 10 PM. To lower and to increase BA concentration during the study, the subjects received cholestyramine and chenodeoxycholic acid (CDCA), respectively, in two examinations. No drug was used in the control examination. There was a pronounced diurnal variation of C4 concentration with a peak around 1 PM in most of the subjects. The area under the curve (AUC) of C4 concentration was five times higher and three times lower when subjects were treated with cholestyramine and CDCA, respectively. No relationship was found between AUC of C4 and AUC of BA concentration, but AUC of C4 correlated positively with that of insulin. Moreover, short-term treatment with cholestyramine resulted in about 10 % suppression of glycemia throughout the day. Our results suggest that insulin is involved in the regulation of diurnal variation of CYP7A1 activity in humans.

• MeSH
• aktivace enzymů MeSH
• anticholesteremika aplikace a dávkování   MeSH
• cholestenony krev   MeSH
• cholesterol-7-alfa-hydroxylasa metabolismus   MeSH
• cholesterol krev   MeSH
• cholestyraminová pryskyřice aplikace a dávkování   MeSH
• cirkadiánní rytmus fyziologie   MeSH
• dospělí MeSH
• gastrointestinální látky aplikace a dávkování   MeSH
• inzulin krev   MeSH
• krevní glukóza metabolismus   MeSH
• kyselina chenodeoxycholová aplikace a dávkování   MeSH
• kyseliny mastné neesterifikované krev   MeSH
• lidé MeSH
• referenční hodnoty MeSH
• triglyceridy krev   MeSH
• žlučové kyseliny a soli metabolismus   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• klinické zkoušky MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 7 alpha-hydroxy-4-cholesten-3-one MeSH Prohlížeč
• anticholesteremika MeSH
• cholestenony MeSH
• cholesterol-7-alfa-hydroxylasa MeSH
• cholesterol MeSH
• cholestyraminová pryskyřice MeSH
• gastrointestinální látky MeSH
• inzulin MeSH
• krevní glukóza MeSH
• kyselina chenodeoxycholová MeSH
• kyseliny mastné neesterifikované MeSH
• triglyceridy MeSH
• žlučové kyseliny a soli MeSH

The treatment of hypercholesterolemia with bile acid (BA) sequestrants results in upregulation of BA synthesis through the classical pathway initiated by cholesterol 7alpha-hydroxylase (CYP7A1). To characterize the detailed dynamics of serum lipid and BA concentrations and the BA synthesis rate in response to treatment with BA sequestrants and to determine whether the -203A/C promoter polymorphism of the CYP7A1 encoding gene (CYP7A1) affects such a response, this pilot study was carried out in healthy men (8 homozygous for the -203A allele and 8 homozygous for the -203C allele of CYP7A1). The subjects were treated for 28 days with colesevelam and blood was drawn for analysis before and on days 1, 3, 7, 14 and 28 of treatment. The response of lipids, BA, fibroblast growth factor-19 (FGF19) and 7alpha-hydroxy-4-cholesten-3-one (C4) to colesevelam did not differ between carriers of -203A and -203C alleles; their data were then aggregated for further analysis. Colesevelam treatment caused immediate suppression of FGF19 concentration and a fivefold increase in CYP7A1 activity, as assessed from C4 concentration, followed by a 17 % decrease in LDL-cholesterol. Although total plasma BA concentrations were not affected, the ratio of cholic acid/total BA rose from 0.25+/-0.10 to 0.44+/-0.16 during treatment at the expense of decreases in chenodeoxycholic and deoxycholic acid.

• MeSH
• alely MeSH
• cholagoga a choleretika farmakologie   MeSH
• cholestenony krev   MeSH
• cholesterol-7-alfa-hydroxylasa genetika   metabolismus   MeSH
• dospělí MeSH
• fibroblastové růstové faktory metabolismus   MeSH
• genotyp MeSH
• hormony štítné žlázy metabolismus   MeSH
• kolesevelam farmakologie   MeSH
• krevní glukóza metabolismus   MeSH
• LDL-cholesterol krev   MeSH
• lidé středního věku MeSH
• lidé MeSH
• metabolismus lipidů účinky léků   MeSH
• pilotní projekty MeSH
• polymorfismus genetický MeSH
• zdraví dobrovolníci pro lékařské studie MeSH
• žlučové kyseliny a soli metabolismus   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 7 alpha-hydroxy-4-cholesten-3-one MeSH Prohlížeč
• cholagoga a choleretika MeSH
• cholestenony MeSH
• cholesterol-7-alfa-hydroxylasa MeSH
• CYP7A1 protein, human MeSH Prohlížeč
• FGF19 protein, human MeSH Prohlížeč
• fibroblastové růstové faktory MeSH
• hormony štítné žlázy MeSH
• kolesevelam MeSH
• krevní glukóza MeSH
• LDL-cholesterol MeSH
• žlučové kyseliny a soli MeSH

Epigallocatechin gallate (EGCG) has been shown to be protective in various experimental models of liver injury, although opposite effects have also been reported. Since its effect on biliary physiology has not been thoroughly investigated, the present study evaluated effect of EGCG on bile flow and bile acid homeostasis in rats. Compared to controls, EGCG treatment decreased bile flow by 23%. Hepatic paracellular permeability and biliary bile acid excretion were not altered by EGCG administration, but biliary glutathione excretion was reduced by 70%. Accordingly, the main glutathione transporter on the hepatocyte canalicular membrane, multidrug resistance-associated protein 2 (Mrp2), was significantly decreased at the protein level. EGCG administration also doubled plasma bile acid levels compared to controls. While protein levels of the main hepatic bile acid transporters were unchanged, the rate-limiting enzyme in the bile acid synthesis, Cyp7a1, was significantly increased by EGCG. Enhanced bile acid synthesis in these animals was also confirmed by a 2-fold increase in plasma marker 7α-hydroxy-4-cholesten-3-one. In contrast, EGCG markedly downregulated major bile acid transporters (Asbt and Ostα) and regulatory molecules (Shp and Fgf15) in the ileum. When EGCG was coadministered with ethinylestradiol, a potent cholestatic agent, it did not show any additional effect on the induced cholestasis. This study shows ability of EGCG to raise plasma bile acid concentrations, mainly through Cyp7a1 upregulation, and to decrease bile production through reduction in Mrp2-mediated bile acid-independent bile flow. In conclusion, our data demonstrate that under certain conditions EGCG may induce cholestasis.

• MeSH
• ABC transportéry genetika   MeSH
• cholestáza chemicky indukované   MeSH
• cholestenony metabolismus   MeSH
• cholesterol-7-alfa-hydroxylasa genetika   metabolismus   MeSH
• down regulace účinky léků   MeSH
• ethinylestradiol farmakologie   MeSH
• glutathion metabolismus   MeSH
• hepatocyty účinky léků   metabolismus   MeSH
• homeostáza účinky léků   MeSH
• ileum účinky léků   metabolismus   MeSH
• katechin analogy a deriváty   toxicita   MeSH
• krysa rodu Rattus MeSH
• permeabilita MeSH
• potkani Wistar MeSH
• upregulace účinky léků   MeSH
• žlučové kyseliny a soli biosyntéza   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 7 alpha-hydroxy-4-cholesten-3-one MeSH Prohlížeč
• ABC transportéry MeSH
• Abcc2 protein, rat MeSH Prohlížeč
• cholestenony MeSH
• cholesterol-7-alfa-hydroxylasa MeSH
• CYP7A1 protein, rat MeSH Prohlížeč
• epigallocatechin gallate MeSH Prohlížeč
• ethinylestradiol MeSH
• glutathion MeSH
• katechin MeSH
• žlučové kyseliny a soli MeSH

The serum concentration of 7α-hydroxy-4-cholesten-3-one (C4), a marker of cholesterol 7α-hydroxylase activity, has recently become an attractive diagnostic tool for researchers interested in cholesterol and bile acid metabolism. The rapidly increasing demand of C4 measurement led to the development of various fast, mostly mass spectrometry-based analytical methods. Our aim was to compare four simple (i.e., not requiring solid phase extraction) extraction procedures (two "one-phase", and two "two-phase") in terms of basic analytical performance and their labouriousness. All methods exhibited comparable extraction recoveries (ranging from 88 to 97%) and intra-assay precision (variation coefficients below 10%), and failed in the removal of phospholipids. Although marked differences were observed in desalting and deproteination, all methods can be considered satisfactory. Simple acetonitrile precipitation can be recommended if a fast extraction and minimal hands-on time is preferred; while two-phase ammonium sulphate:acetonitrile extraction should be chosen when maximal deproteination is required.

• Klíčová slova
• 7α-Hydroxy-4-cholesten-3-one, Bile acids, Cholesterol 7α-hydroxylase, Mass spectrometry,
• MeSH
• biologické markery krev   MeSH
• cholestenony krev   MeSH
• chromatografie kapalinová metody   MeSH
• fosfolipidy izolace a purifikace   MeSH
• hmotnostní spektrometrie metody   MeSH
• lidé MeSH
• žlučové kyseliny a soli biosyntéza   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• 7 alpha-hydroxy-4-cholesten-3-one MeSH Prohlížeč
• biologické markery MeSH
• cholestenony MeSH
• fosfolipidy MeSH
• žlučové kyseliny a soli MeSH

BACKGROUND: Bile salts likely contribute to liver injury in patients with primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC). Fibroblast growth factor 19 (FGF19) is a bile salt-induced enterokine with hepatoprotective potential as it suppresses de novo bile salt synthesis. Here, we evaluated the bile salt receptor FXR/FGF19 gut-liver axis in PSC and PBC patients. METHODS: Fasted patients with PSC (n = 12) and PBC (n = 10), and healthy controls (HC; n = 10) were orally challenged with the natural FXR agonist chenodeoxycholic acid (CDCA 15 mg/kg). Blood was sampled hourly until 8 h afterwards. Serum FGF19 and bile salt excursions were determined. Serum levels of 7α-hydroxy-4-cholesten-3-one (C4), reflecting bile salt synthesis, were measured as a biomarker of FGF19 response. RESULTS: Baseline serum FGF19 levels were comparable between groups, while fasted bile salt levels in PSC patients were elevated. Upon CDCA challenge, HC and PBC patients showed a serum FGF19 peak after 4 h followed by a decline. PSC patients showed a prolonged and elevated serum FGF19 response up to 8 h, combined with a sustained serum elevation of CDCA and other bile salts. In general, C4 levels declined following FGF19 elevation. In PSC patients with less favorable prognosis, baseline C4 levels were drastically suppressed and did not further decline. CONCLUSION: Following an oral CDCA challenge, PSC patients showed an impaired clearance of CDCA and a prolonged serum FGF19 response. FXR agonist therapy in PSC could cause prolonged exposure to elevated levels of FGF19, and we propose careful monitoring for detrimental side effects in patient studies.

• Klíčová slova
• Chenodeoxycholic acid, Farnesoid X receptor, Fibroblast growth factor 19, Primary sclerosing cholangitis,
• MeSH
• aplikace orální MeSH
• cholestenony krev   MeSH
• dospělí MeSH
• fibroblastové růstové faktory krev   metabolismus   MeSH
• játra metabolismus   MeSH
• klinické protokoly MeSH
• kyselina chenodeoxycholová aplikace a dávkování   MeSH
• lidé středního věku MeSH
• lidé MeSH
• purgativa aplikace a dávkování   MeSH
• senioři MeSH
• sklerozující cholangitida krev   farmakoterapie   metabolismus   MeSH
• střevní sliznice metabolismus   MeSH
• studie případů a kontrol MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 7 alpha-hydroxy-4-cholesten-3-one MeSH Prohlížeč
• cholestenony MeSH
• FGF19 protein, human MeSH Prohlížeč
• fibroblastové růstové faktory MeSH
• kyselina chenodeoxycholová MeSH
• purgativa MeSH