![[Feedback]](/icons/banner/feedbackACT.gif){kind=icon}
![[For Subscribers]](/icons/banner/subscriberACT.gif){kind=icon}
![[Archive]](/icons/banner/archiveACT.gif){kind=icon}
![[Search]](/icons/banner/searchACT.gif){kind=icon}
![[Contents]](/icons/banner/tocACT.gif){kind=icon}
|
|
|
|
|
||
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Inhibitor Ursodeoxycholic Acid Influences Pharmacokinetics of the Organic Anion Transporting Polypeptide 1B1 Substrate Rosuvastatin and BilirubinPharmacogenetics Research Institute, Institute of Clinical Pharmacology, Central South University, Changsha, Hunan, China (Y.-J.H., W.Z., J.-H.T., Y.C., D.G., Q.L., Z.-Y.L., H.C., D.-L.H., D.W., H.-H.Z.); and Institute of Natural Products and Clinical Pharmacology, University of Ulm, Ulm, Germany (Y.-J.H., J.K.)
(Received January 16, 2008; Accepted April 23, 2008)
 |
Abstract |
|---|
 Top Abstract Materials and MethodsResults and DiscussionReferences |
|---|
. The aim of this study was to investigate the effect of ursodeoxycholic acid (UDCA), an inhibitor of transcription factor HNF1, on rosuvastatin and bilirubin kinetics in human healthy volunteers. Both substances are substrates of OATP1B1. Twelve subjects with OATP1B1*1b/*1b genotype predicting high transport activity were recruited for this randomized, crossover study. Each subject received a single p.o. dose of 20 mg of rosuvastatin after 14 days of p.o. intake of either 500 mg of UDCA or placebo. Plasma concentrations of rosuvastatin were determined on days 15 to 18 of each study period. Subjects were randomly assigned to UDCA or placebo group. Intake of UDCA led to a significant increase in rosuvastatin area under the curve (AUC)0–72 from 128.5 ng/ml · h to 182.1 ng/ml · h(P = 0.008) compared with the control group. The oral clearance decreased from 155.2 l/h with placebo to 109.8 l/h with UDCA. In addition, the mean values of total bilirubin, conjugated bilirubin, and unconjugated bilirubin significantly increased to 139 ± 39% (P = 0.003), 127 ± 29% (P = 0.005), and 151 ± 52% (P = 0.004), respectively, after UDCA treatment. These results in healthy volunteers confirm the findings from in vitro studies that UDCA inhibits OATP1B1 activity by inhibition of the transcription factor HNF1. They highlight a novel mechanism of OATP1B1-based interaction that is mediated by transcription factor HNF1.
; Olsson et al., 2002). Recent studies revealed that rosuvastatin is not extensively metabolized by cytochrome P450 isoenzyme CYP2C9, with only 10% of the radiolabeled dose excreted as metabolites in urine (Carswell et al., 2002; Martin et al., 2003). This pharmacological profile indicates that cytochrome P450–mediated drug interactions with rosuvastatin are unlikely to be clinically important. Indeed, coadministration of rosuvastatin (10–80 mg once daily) with ketoconazole, erythromycin, itraconazole, fenofibrate, fluconazole, digoxin, and warfarin had no clinically significant effect on the pharmacokinetics of rosuvastatin or vice versa (Cooper et al., 2002, 2003a,b,c; Martin et al., 2002).
Rosuvastatin predominantly undergoes biliary excretion, and 90% of a single p.o. administered dose is recovered unchanged in feces (Martin et al., 2003), indicating that carrier-mediated hepatic transport may be important for disposition and potential drug interactions with rosuvastatin. Members of the organic anion transporting polypeptide (OATP) superfamily have been shown to be active transporters of rosuvastatin (McTaggart, 2003; Simonson et al., 2004). Coadministration of rosuvastatin with gemfibrozil and cyclosporine, which are known inhibitors of OATP1B1, led to an increase of rosuvastatin Cmax (2–11-fold) and area under the curve (AUC) (2–7-fold) (Schuster, 2003; Schneck et al., 2004; Shitara et al., 2004).
In the human body, bile acids are signaling molecules that activate several nuclear receptors and thereby regulate many physiological pathways and processes to maintain bile acid and cholesterol homeostasis (Trauner and Boyer, 2003). The OATP1B1 proximal promoter contains a functional hepatocyte nuclear factor 1 (HNF1) response element that is responsible for the hepatic expression of OATP1B1. In rats, the disruption of HNF1 causes a marked decrease of Oat and Oatp expression in liver and kidney (Maher et al., 2006). Studies in human cell lines, HepG2 and Huh7, show that bile acids including chenodeoxycholic acid, deoxycholic acid, lithocholic acid, cholic acid, and ursodeoxycholic acid (UDCA) decrease OATP1B1 expression through direct repression of HNF1 (Jung et al., 2001; Jung and Kullak-Ublick, 2003). It has been shown that UDCA is responsible for a decreased expression of OATP1B1 by directly inhibiting the activity of HNF1, which plays a key role in modulating OATP1B1 mRNA expression (Jung et al., 2001; Jung and Kullak-Ublick, 2003). Therefore, we hypothesize that UDCA may interact with rosuvastatin by inhibiting OATP1B1 through HNF1 in vivo.
In this crossover clinical trial, we studied the effect of long-term (14 days) UDCA intake on rosuvastatin kinetics in healthy volunteers. Because bilirubin is also transported into the liver by OATP1B1, the serum bilirubin level was measured before and after UDCA treatment concomitantly.
|
Materials and Methods |
|---|
|
TopAbstractMaterials and MethodsResults and DiscussionReferences |
|---|
). The study protocol was approved by the Ethics Committee of Xiangya School of Medicine, Central South University, and written informed consent was obtained from all the participants. Study Design. Subjects were randomized to one of the two treatment groups. Group A: Volunteers received p.o. doses of 500 mg of UDCA (two 250-mg capsules of Ursofalk; Dr. Falk Pharma GMBH, Freiburg, Germany) once daily for 14 days. On day 15, after an overnight fast, a single p.o. dose of 20 mg of rosuvastatin (one 20-mg tablet, Crestor, licensed by AstraZeneca from Shionogi and Co. Ltd., Osaka, Japan) was administered with 150 ml of tap water at 8 AM. Meals were standardized, and the first meal was allowed 4 h after rosuvastatin administration. Venous blood samples (5 ml) were collected before and at 0.5, 1, 2, 3, 4, 5, 6, 8, 10, 12, 16, 24, 36, 48, and 72 h after rosuvastatin intake. Plasma was separated by centrifugation within 30 min and immediately stored at -20°C. From days 19 to 33, the participants received placebos once daily for 14 days. On day 34, 20 mg of rosuvastatin was administered as described for day 15, and blood samples were collected as described above. Group B was treated with placebo first and later with UDCA. Participants were randomly assigned to either group A or group B.
Analytical Drug Assays. Plasma concentrations of rosuvastatin were analyzed by liquid chromatography/mass spectrometry with electrospray ionization source (LCQ Deca XP Plus; Thermo Finnigan, San Jose, CA) as described in our previous work (Zhang et al., 2006). The limit of quantification for rosuvastatin was 0.1 ng/ml, and the calibration curve was linear from 0.2 to 50 ng/ml (R2 = 0.995). Coefficients of variation for accuracy and precision were <15%. All the data were evaluated by Analyst software Xcalibur (Thermo Finnigan).
Bilirubin Analysis. Venous blood samples were collected before and after UDCA phase for each subject. Total bilirubin (TB), conjugated bilirubin (CB), and unconjugated bilirubin (UB) were measured by Auto Biochemistry Analyzer (7600-020; Hitachi, Tokyo, Japan) in the 1st Xiang Ya Hospital, Central South University.
Pharmacokinetics. Concentration data were analyzed by noncompartmental pharmacokinetic methods using WinNonlin version 1.5 (Pharsight, Mountain View, CA). Maximal plasma concentrations of rosuvastatin were the respective data as measured. AUC was calculated using the linear trapezoidal rule with extrapolation from 0 to infinity or from 0 to 72 h. The total oral clearance was calculated as dose/AUC.
Statistical Analysis. Statistical analysis was performed by the SPSS software for Windows (version 12.0; SPSS Inc., Chicago, IL). Data are expressed as mean ± S.D. Normality test was conducted on all the pharmacokinetic parameters. Differences in rosuvastatin kinetic parameters and bilirubin concentrations between placebo and UDCA intake within the individuals were tested using univariate analysis of variance using individual code number, drug (placebo or UDCA), and group (A or B) as between-subject factors. A P < 0.05 was considered significant.
|
Results and Discussion |
|---|
|
TopAbstractMaterials and MethodsResults and DiscussionReferences |
|---|
of rosuvastatin from 145.5 to 231.9 ng/ml · h (P = 0.004) compared with the control group. The mean oral clearance of rosuvastatin significantly decreased from 174.6 l/h (placebo) to 128.2 l/h (UDCA) (P = 0.003). The mean values of Cmax, Tmax, and t1/2 remained statistically unaltered by UDCA. In addition to its effect on rosuvastatin disposition, UDCA significantly increased the TB, CB, and UB values in 12 healthy subjects (Table 1). The mean increase of TB, CB, and UB was 139 ± 39% (P = 0.003), 127 ± 29% (P = 0.005), and 151 ± 52% (P = 0.004), respectively.
|
|
These results show that the use of a therapeutic dose (500 mg, q.d.) of UDCA continuously for 14 days significantly interacts with rosuvastatin elimination, causing a moderate increase in plasma concentrations of about 30%. In addition, a similar increase in plasma bilirubin was detected, supporting the hypothesis that UDCA might inhibit OATP1B1 activity in the human body.
Direct competitive inhibition of OATP1B1 can lead to a drastic increase in drug exposure. For example, cyclosporine increased the plasma concentrations of repaglinide (2.5-fold) significantly by inhibiting OATP1B1-mediated hepatic uptake (Treiber et al., 2004; Kajosaari et al., 2005). Rifampin significantly increased the AUC value of atorvastatin acid, which is mainly excreted by OATP1B1, by 6.8-fold (Lau et al., 2007). In this study we focused on a different mechanism underlying the inhibition of OATP1B1 function that involves interference with the HNF1 transcription factor and decreased expression of the transporter. However, this mechanism leads to smaller differences in rosuvastatin kinetics compared with competitive inhibition. We acknowledge that the regulation of OATP1 expression is complex, and other transcription factors such the constitutive androstane receptor, pregnane X receptor, peroxisome proliferator-activated receptor, farnesoid X receptor, and small heterodimer partner may play a role in regulating OATP1B1 expression as these factors have been found in the promoter and enhancer region of Oatp2 in rats (Cheng et al., 2005).
UDCA is taken up into the liver only in a Na+-dependent manner, and no significant uptake via OATP1B1 was observed, which indicates that UDCA is unlikely to competitively interact with rosuvastatin uptake (Maeda et al., 2006). On the other hand, two major transport systems are involved in rosuvastatin uptake: the majority is taken up via OATP1B1, and about 35% is transported by the sodium-dependent taurocholate cotransporting polypeptide (NTCP, SLC10A1) (Ho et al., 2006). Whereas rifampin directly inhibits both transporters (Mita et al., 2006; Lau et al., 2007), inhibition of HNF1 will only affect OATP1B1 and not NTCP (Jung et al., 2004). Thus, specific inhibition of OATP1B1 via HNF1 may explain the minor effect of UDCA on rosuvastatin kinetics compared with the effects of rifampin. UDCA also can be transported by NTCP, and competitive inhibition of NTCP may be an alternative explanation for the effects of UDCA on rosuvastatin kinetics especially because UDCA exhibits a long half-life of 3.5 to 5.8 days.
Significantly increased bilirubin levels were observed after 14 days of intake of UDCA. Many studies have shown that OATP1B1 mediates bilirubin uptake from blood into the liver, and low activity of OATP1B1 may be a risk factor for hyperbilirubinemia in neonates (Cui et al., 2001; Huang et al., 2004). Because bilirubin is apparently not transported by NTCP, down-regulation of OATP1B1 activity by UDCA is a likely mechanism explaining the observed bilirubin increase in peripheral blood, and this supports our interpretation of the rosuvastatin-UDCA interaction.
Because HNF1 is also a transcription factor for other genes involved in drug metabolism, it would be interesting to study to what extent HNF1 inhibition by UDCA may influence the expression of a group of other important gene products, including CYP2E1, UGT2B7, ApoA-II, among others (Ueno and Gonzalez, 1990; Chambaz et al., 1991; Ishii et al., 2000).
Two functional variants of HNF1, ILe27Leu and Asn487Ser, have been described that are correlated with insulin sensitivity in humans and may lead to maturity-onset diabetes of the young type 3 (Fajans et al., 2001; Ryffel, 2001). In another study, we measured rosuvastatin kinetics in eight carriers of ILe27Leu and eight carriers of Asn487Ser variants compared with wild-types. However, none of the mutations led to any change in pharmacokinetics of rosuvastatin (Y.-J. He, unpublished data). Further studies are required to clarify the potential impact of these variants on the expression of OATP1B1 in hepatocytes.
In conclusion, UDCA increased the systemic exposure of rosuvastatin and serum bilirubin in healthy volunteers, most probably because of a decrease in OATP1B1 transporter expression by inhibition of the transcription factor HNF1. The influence on pharmacokinetic parameters of rosuvastatin was less compared with interaction with substances that directly inhibit OATP1B1. Because of the modest change of pharmacokinetics parameters, the clinical impact of the UDCA and rosuvastatin interaction may be moderate. However, because other genes are regulated by HNF1, attention to other types of drug interactions should be paid when UDCA is used in clinically.
|
Footnotes |
|---|
Article, publication date, and citation information can be found at http://dmd.aspetjournals.org.
ABBREVIATIONS: OATP, organic anion transporting polypeptide; AUC, area under the curve; HNF1, hepatic nuclear factor 1; UDCA, ursodeoxycholic acid; TB, total bilirubin; CB, conjugated bilirubin; UB, unconjugated bilirubin; NTCP, sodium-dependent taurocholate cotransporting polypeptide.
Address correspondence to: Hong-Hao Zhou, Pharmacogenetics Research Institute, Institute of Clinical Pharmacology, Central South University, Changsha, Hunan 410078, China. E-mail: hhzhou{at}public.cs.hn.cn
|
References |
|---|
|
TopAbstractMaterials and MethodsResults and DiscussionReferences |
|---|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 |
 |
 |
|
 |
 |
 |
