Uptake Of Rosuvastatin Research Articles

Identification of Hepatic Phospholipidosis Inducers in Sandwich-Cultured Rat Hepatocytes, a Physiologically Relevant Model, Reveals Altered Basolateral Uptake and Biliary Excretion of Anionic Probe Substrates

Drug-induced phospholipidosis (PLD) is characterized by phospholipid accumulation within the lysosomes of affected tissues, resulting in lysosomal enlargement and laminar body inclusions. Numerous adverse effects and toxicities have been linked to PLD-inducing drugs, but it remains unknown whether drug-induced PLD represents a distinct toxicity or cellular adaptation. In silico and immortalized cellular models have been used to evaluate the PLD potential of new drugs, but these systems have some limitations. The aims of this study were to determine whether primary sandwich-cultured hepatocytes (SCH) can serve as a sensitive and selective model to evaluate hepatic drug-induced PLD, and to evaluate the impact of PLD on the uptake and biliary excretion of probe substrates, taurocholate (TC) and rosuvastatin (RSV). Rat SCH were cultured for 48 h with prototypic hepatic PLD-inducing drugs, amiodarone (AMD), chloroquine (CHQ), desipramine (DES), and azithromycin (AZI), as well as the renal PLD inducer gentamicin (GTM). LysoTracker Red localization and transmission electron microscopy indicated enlarged lysosomal compartments and laminar body inclusions in SCH treated with AMD, CHQ, DES, and AZI, but not GTM, relative to control. PLD resulted in a 51-92% decrease in the in vitro biliary clearance of both TC and RSV; the biliary excretion index significantly decreased for TC from 88 to 35-73%. These data suggested that PLD significantly reduced both organic anion transporting polypeptide-mediated uptake, and bile salt export pump-mediated biliary transport processes. The current study demonstrates that the rat SCH system is a promising model to study hepatic PLD in vitro. Altered hepatic transport of anionic substrates secondary to drug-induced PLD is a novel finding.

Interaction of Novel Platelet-Increasing Agent Eltrombopag with Rosuvastatin via Breast Cancer Resistance Protein in Humans

Eltrombopag (ELT), an orally available thrombopoietin receptor agonist, is a substrate of organic anion transporting polypeptide 1B1 (OATP1B1), and coadministration of ELT increases the plasma concentration of rosuvastatin in humans. Since the pharmacokinetic mechanism(s) of the interaction is unknown, the present study aimed to clarify the drug interaction potential of ELT at transporters. The OATP1B1-mediated uptake of ELT was inhibited by several therapeutic agents used to treat lifestyle diseases. Among them, rosuvastatin was a potent inhibitor with an IC(50) of 0.05 µM, which corresponds to one-seventh of the calculated maximum unbound rosuvastatin concentration at the inlet to the liver. Nevertheless, a simulation study using a physiologically based pharmacokinetic model predicted that the effect of rosuvastatin on the pharmacokinetic profile of ELT in vivo would be minimal. On the other hand, ELT potently inhibited uptake of rosuvastatin by OATP1B1 and human hepatocytes, with an IC(50) of 0.1 µM. However, the results of the simulation study indicated that inhibition of OATP1B1 by ELT can only partially explain the clinically observed interaction with rosuvastatin. ELT also inhibited transcellular transport of rosuvastatin in MDCKII cells stably expressing breast cancer resistance protein (BCRP), and was found to be a substrate of BCRP. The interaction of ELT with rosuvastatin can be almost quantitatively explained on the assumption that intestinal secretion of rosuvastatin is essentially completely inhibited by ELT. These results suggest that BCRP in small intestine may be the major target for interaction between ELT and rosuvastatin in humans.

Quantitative assessment of the contribution of sodium‐dependent taurocholate co‐transporting polypeptide (NTCP) to the hepatic uptake of rosuvastatin, pitavastatin and fluvastatin

Hepatic uptake transport is often the rate-determining step in the systemic clearance of drugs. The ability to predict uptake clearance and to determine the contribution of individual transporters to overall hepatic uptake is therefore critical in assessing the potential pharmacokinetic and pharmacodynamic variability associated with drug-drug interactions and pharmacogenetics. The present study revisited the interaction of statin drugs, including pitavastatin, fluvastatin and rosuvastatin, with the sodium-dependent taurocholate co-transporting polypeptide (NTCP) using gene transfected cell models. In addition, the uptake clearance and the contribution of NTCP to the overall hepatic uptake were assessed using in vitro hepatocyte models. Then NTCP protein expression was measured by a targeted proteomics transporter quantification method to confirm the presence and stability of NTCP expression in suspended and cultured hepatocyte models. It was concluded that NTCP-mediated uptake contributed significantly to active hepatic uptake in hepatocyte models for all three statins. However, the contribution of NTCP-mediated uptake to the overall active hepatic uptake was compound-dependent and varied from about 24% to 45%. Understanding the contribution of individual transporter proteins to the overall hepatic uptake and its functional variability when other active hepatic uptake pathways are interrupted could improve the current prediction practice used to assess the pharmacokinetic variability due to drug-drug interactions, pharmacogenetics and physiopathological conditions in humans.

Hepatic Basolateral Efflux Contributes Significantly to Rosuvastatin Disposition I: Characterization of Basolateral Versus Biliary Clearance Using a Novel Protocol in Sandwich-Cultured Hepatocytes

Transporters responsible for hepatic uptake and biliary clearance (CLBile) of rosuvastatin (RSV) have been well characterized. However, the contribution of basolateral efflux clearance (CLBL) to hepatic and systemic exposure of RSV is unknown. Additionally, the appropriate design of in vitro hepatocyte efflux experiments to estimate CLBile versus CLBL remains to be established. A novel uptake and efflux protocol was developed in sandwich-cultured hepatocytes (SCH) to achieve desired tight junction modulation while maintaining cell viability. Subsequently, studies were conducted to determine the role of CLBL in the hepatic disposition of RSV using SCH from wild-type (WT) and multidrug resistance-associated protein 2 (Mrp2)-deficient (TR(-)) rats in the absence and presence of the P-glycoprotein and breast cancer resistance protein (Bcrp) inhibitor elacridar (GF120918). RSV CLBile was nearly ablated by GF120918 in TR(-) SCH, confirming that Mrp2 and Bcrp are responsible for the majority of RSV CLBile. Pharmacokinetic modeling revealed that CLBL and CLBile represent alternative elimination routes with quantitatively similar contributions to the overall hepatocellular excretion of RSV in rat SCH under baseline conditions (WT SCH in the absence of GF120918) and also in human SCH. Membrane vesicle experiments revealed that RSV is a substrate of MRP4 (Km = 21 ± 7 µM, Vmax = 1140 ± 210 pmol/min per milligram of protein). Alterations in MRP4-mediated RSV CLBL due to drug-drug interactions, genetic polymorphisms, or disease states may lead to changes in hepatic and systemic exposure of RSV, with implications for the safety and efficacy of this commonly used medication.

Tricyclic compounds inhibit the OATP1A2 transporter

BackgroundOATP1A2 is a membrane transporter potentially involved in the absorption of various drugs. Previous data demonstrated that the uptake of rosuvastatin through OATP1A2 can be inhibited by several β‐blockers, where carvedilol is the most potent inhibitor. Carvedilol structurally differs from the other β‐blockers tested by its tricyclic moiety. The goal of this study was to determine whether the tricyclic structure of carvedilol is responsible for its strong inhibitory effect on OATP1A2.MethodsA HEK293 cell line overexpressing OATP1A2 was used as model. They were co‐incubated in the presence of rosuvastatin and increasing concentrations of different tricyclic compounds. The amount of rosuvastatin transported in the cells was measured by HPLC.ResultsMost tricyclic compounds evaluated inhibited rosuvastatin uptake through OATP1A2 with different IC50. Our data show that the inhibition is competitive. Compound IC50 (μM) Compound IC50 (μM) carazolol 4.0 nortriptyline 14.8 amitriptyline 5.0 chlorpromazine 29.6 imipramine 12.6 desipramine 77.9 trimipramine 13.6 carbamazepine >;100 doxepin 14.0 carbazole No effect clomipramine 14.7 phenothiazine No effect ConclusionsThe inhibitory component is made up of the tricyclic ring with a short aliphatic chain. Consequently, drugs with a similar structure may strongly modulate the transport of OATP1A2 substrates.Funding: CIHR, FRSQ, Foundation CHUM

Interaction of Silymarin Flavonolignans with Organic Anion-Transporting Polypeptides

Organic anion-transporting polypeptides (OATPs) are multispecific transporters mediating the uptake of endogenous compounds and xenobiotics in tissues that are important for drug absorption and elimination, including the intestine and liver. Silymarin is a popular herbal supplement often used by patients with chronic liver disease; higher oral doses than those customarily used (140 mg three times/day) are being evaluated clinically. The present study examined the effect of silymarin flavonolignans on OATP1B1-, OATP1B3-, and OATP2B1-mediated transport in cell lines stably expressing these transporters and in human hepatocytes. In overexpressing cell lines, OATP1B1- and OATP1B3-mediated estradiol-17β-glucuronide uptake and OATP2B1-mediated estrone-3-sulfate uptake were inhibited by most of the silymarin flavonolignans investigated. OATP1B1-, OATP1B3-, and OATP2B1-mediated substrate transport was inhibited efficiently by silymarin (IC₅₀ values of 1.3, 2.2 and 0.3 µM, respectively), silybin A (IC₅₀ values of 9.7, 2.7 and 4.5 µM, respectively), silybin B (IC₅₀ values of 8.5, 5.0 and 0.8 µM, respectively), and silychristin (IC₅₀ values of 9.0, 36.4, and 3.6 µM, respectively). Furthermore, silymarin, silybin A, and silybin B (100 µM) significantly inhibited OATP-mediated estradiol-17β-glucuronide and rosuvastatin uptake into human hepatocytes. Calculation of the maximal unbound portal vein concentrations/IC₅₀ values indicated a low risk for silymarin-drug interactions in hepatic uptake with a customary silymarin dose. The extent of silymarin-drug interactions depends on OATP isoform specificity and concentrations of flavonolignans at the site of drug transport. Higher than customary doses of silymarin, or formulations with improved bioavailability, may increase the risk of flavonolignan interactions with OATP substrates in patients.

Drug-Drug Interactions between Rosuvastatin and Oral Antidiabetic Drugs Occurring at the Level of OATP1B1

Organic anion-transporting polypeptide 1B1 (OATP1B1) is an important hepatic uptake transporter, of which the polymorphic variant OATP1B1*15 (Asn130Asp and Val174Ala) has been associated with decreased transport activity. Rosuvastatin is an OATP1B1 substrate and often concomitantly prescribed with oral antidiabetics in the clinic. The aim of this study was to investigate possible drug-drug interactions between these drugs at the level of OATP1B1 and OATP1B1*15. We generated human embryonic kidney (HEK)293 cells stably overexpressing OATP1B1 or OATP1B1*15 that showed similar protein expression levels of OATP1B1 and OATP1B1*15 at the cell membrane as measured by liquid chromatography-tandem mass spectrometry. In HEK-OATP1B1*15 cells, the V(max) for OATP1B1-mediated transport of E(2)17β-G (estradiol 17β-d-glucuronide) was decreased >60%, whereas K(m) values (Michaelis constant) were comparable. Uptake of rosuvastatin in HEK-OATP1B1 cells (K(m) 13.1 ± 0.43 μM) was nearly absent in HEK-OATP1B1*15 cells. Interestingly, several oral antidiabetics (glyburide, glimepiride, troglitazone, pioglitazone, glipizide, gliclazide, and tolbutamide), but not metformin, were identified as significant inhibitors of the OATP1B1-mediated transport of rosuvastatin. The IC(50) values for inhibition of E(2)17β-G uptake were similar between OATP1B1 and OATP1B1*15. In conclusion, these studies indicate that several oral antidiabetic drugs affect the OATP1B1-mediated uptake of rosuvastatin in vitro. The next step will be to translate these data to the clinical situation, as it remains to be established whether the studied oral antidiabetics indeed affect the clinical pharmacokinetic profile of rosuvastatin in patients.

The Role of a Basolateral Transporter in Rosuvastatin Transport and Its Interplay with Apical Breast Cancer Resistance Protein in Polarized Cell Monolayer Systems

Membrane transporters can play a clinically important role in drug absorption and disposition; Caco-2 and Madin-Darby canine kidney (MDCK) cells are the most widely used in vitro models for studying the functions of these transporters and associated drug interactions. Transport studies using these cell models are mostly focused on apical transporters, whereas basolateral drug transport processes are largely ignored. However, for some hydrophilic drugs, a basolateral uptake transporter may be required for drugs to enter cells before they can interact with apical efflux transporters. The objective of this study was to evaluate potential differences in drug transport across Caco-2 and MDCK basolateral membrane that could cause discrepancy in the identification of efflux transporter substrates and to elucidate the underlying factors that may cause such differences, using rosuvastatin as a model substrate. Bidirectional transport results in Caco-2 and breast cancer resistance protein-MDCK cells demonstrated the necessity of an uptake transporter at the basolateral membrane for rosuvastatin. Kinetic study revealed saturable and nonsaturable processes for rosuvastatin uptake across the Caco-2 basolateral membrane, with the saturable process encompassing >75% of overall rosuvastatin basolateral uptake at concentrations below the K(m) (4.2 μM). Furthermore, rosuvastatin basolateral transport exhibited cis-inhibition and trans-stimulation phenomena, indicating a facilitated diffusion mechanism. This basolateral transporter appeared to be a prerequisite for rosuvastatin and perhaps for other hydrophilic substrates to interact with apical efflux transporters. Deficit of such a basolateral transporter in certain cell models may lead to false-negative results when screening drug interactions with apical efflux transporters.

Transepithelial transport of rosuvastatin and effect of ursolic acid on its transport in Caco-2 monolayers

The aim of this study was to determine transepithelial transport characteristics of rosuvastatin and effect of ursolic acid (P-gp potential inhibitor) and ko143 (ABC transporters selective inhibitor) on its transport in Caco-2 monolayers. A reliable Caco-2 cell monolayers model was established. The TEER value was used to inspect integrity of cell model. Apparent permeability coefficients (Papp(BL-AP) and Papp(AP-BL)) were used to analyze transepithelial transport of rosuvastatin. Uptake of rosuvastatin was time- and concentration-dependent in Caco-2 cell. The ko143 but not ursolic acid had effect on the uptake of rosuvastatin in Caco-2 cell monolayer model and affected apparent permeability coefficient and apparent permeability of rosuvastatin. Active transport and passive diffusion absorption existed in transepithelial transport of rosuvastatin in Caco-2 cell model. Ursolic acid had no effect on transport of rosuvastatin in Caco-2 cell monolayer. The result indicated that ursolic acid may not cause effect on intestinal absorption of rosuvastatin.

Simultaneous Assessment of Uptake and Metabolism in Rat Hepatocytes: A Comprehensive Mechanistic Model

Kinetic parameters describing hepatic uptake in hepatocytes are frequently estimated without appropriate incorporation of bidirectional passive diffusion, intracellular binding, and metabolism. A mechanistic two-compartment model was developed to describe all of the processes occurring during the in vitro uptake experiments performed in freshly isolated rat hepatocytes plated for 2 h. Uptake of rosuvastatin, pravastatin, pitavastatin, valsartan, bosentan, telmisartan, and repaglinide was investigated over a 0.1 to 300 μM concentration range at 37°C for 2 or 45-90 min; nonspecific binding was taken into account. All concentration-time points were analyzed simultaneously by using a mechanistic two-compartment model describing uptake kinetics [unbound affinity constant (K(m,u)), maximum uptake rate (V(max)), unbound active uptake clearance (CL(active,u))], passive diffusion [unbound passive diffusion clearance (P(diff,u))], and intracellular binding [intracellular unbound fraction (fu(cell))]. When required (telmisartan and repaglinide), the model was extended to account for the metabolism [unbound metabolic clearance (CL(met,u))]. The CL(active,u) ranged 8-fold, reflecting a 11-fold range in uptake K(m,u), with telmisartan and valsartan showing the highest affinity for uptake transporters (K(m,u) <10 μM). Both P(diff,u) and fu(cell) span over two orders of magnitude and reflected the lipophilicity of the drugs in the dataset. An extended incubation time allowed steady state to be reached between media and intracellular compartment concentrations and reduced the error in certain parameter estimates observed with shorter incubation times. Active transport accounted for >70% of total uptake for all drugs investigated and was 4- and 112-fold greater than CL(met,u) for telmisartan and repaglinide, respectively. Modeling of uptake kinetics in conjunction with metabolism improved the precision of the uptake parameter estimates for repaglinide and telmisartan. Recommendations are made for uptake experimental design and modeling strategies.

Eltrombopag increases plasma rosuvastatin exposure in healthy volunteers

OATP1B1 is important for hepatic uptake of rosuvastatin and BCRP is important for rosuvastatin absorption and elimination. Eltrombopag inhibits OATP1B1 and BCRP in vitro at clinically relevant concentrations. Inhibition of these transporters could change cholesterol-lowering efficacy and increase the risk of exposure-dependent toxicities. To determine if co-administration of eltrombopag with rosuvastatin alters plasma rosuvastatin exposure, an open-label study was conducted in 42 healthy adult subjects. Concomitant administration of eltrombopag with rosuvastatin was associated with increased rosuvastatin exposure via inhibition of drug transporters. The therapeutic index of HMG Co-A reductase inhibitors may be reduced by the concomitant use of eltrombopag. In subjects taking eltrombopag, a reduced dose of HMG Co-A reductase inhibitors may be needed. Eltrombopag, an oral, nonpeptide thrombopoietin receptor agonist, inhibits the organic anion transporting polypeptide 1B1 (OATP1B1) and breast cancer resistance protein (BCRP) in vitro. OATP1B1 is important for hepatic uptake of rosuvastatin and inhibition of this transporter could reduce cholesterol-lowering efficacy and increase the risk of exposure-dependent toxicities. In contrast, BCRP is an efflux transporter and inhibition of this transporter could increase both hepatic and plasma rosuvastatin concentrations, resulting in increased efficacy and toxicity. To determine if co-administration of eltrombopag with rosuvastatin alters plasma rosuvastatin exposure, an open-label study was conducted in 42 healthy adult subjects. Subjects received rosuvastatin and eltrombopag orally: day 1, rosuvastatin 10 mg single dose; days 6 to 9, eltrombopag 75 mg once daily; day 10, eltrombopag 75 mg once daily and rosuvastatin 10 mg single dose. Adverse event assessments were performed daily and at the follow-up visit. Plasma samples for pharmacokinetic analysis were collected days 1 to 5 and days 10 to 14. Co-administration of eltrombopag with rosuvastatin increased geometric mean (90% confidence interval) plasma rosuvastatin AUC(0,∞) by 55% (42%, 69%) and C(max) by 103% (82%, 126%) in the overall study population, with a larger interaction in the non-Asian compared with Asian subjects. Concomitant administration of eltrombopag with rosuvastatin was associated with increased rosuvastatin exposure. The therapeutic index of HMG Co-A reductase inhibitors may be reduced by the concomitant use of eltrombopag. In subjects taking eltrombopag, a reduced dose of HMG Co-A reductase inhibitors may be needed.

PH-Sensitive Interaction of HMG-CoA Reductase Inhibitors (Statins) with Organic Anion Transporting Polypeptide 2B1

The human organic anion transporting polypeptide 2B1 (OATP2B1, SLCO2B1) is ubiquitously expressed and may play an important role in the disposition of xenobiotics. The present study aimed to examine the role of OATP2B1 in the intestinal absorption and tissue uptake of 3-hydroxy-3-methylglutaryl-Coenzyme A (HMG-CoA) reductase inhibitors (statins). We first investigated the functional affinity of statins to the transporter as a function of extracellular pH, using OATP2B1-transfeced HEK293 cells. The results indicate that OATP2B1-mediated transport is significant for rosuvastatin, fluvastatin and atorvastatin, at neutral pH. However, OATP2B1 showed broader substrate specificity as well as enhanced transporter activity at acidic pH. Furthermore, uptake at acidic pH was diminished in the presence of proton ionophore, suggesting proton gradient as the driving force for OATP2B1 activity. Notably, passive transport rates are predominant or comparable to active transport rates for statins, except for rosuvastatin and fluvastatin. Second, we studied the effect of OATP modulators on statin uptake. At pH 6.0, OATP2B1-mediated transport of atorvastatin and cerivastatin was not inhibitable, while rosuvastatin transport was inhibited by E-3-S, rifamycin SV and cyclosporine with IC(50) values of 19.7 ± 3.3 μM, 0.53 ± 0.2 μM and 2.2 ± 0.4 μM, respectively. Rifamycin SV inhibited OATP2B1-mediated transport of E-3-S and rosuvastatin with similar IC(50) values at pH 6.0 and 7.4, suggesting that the inhibitor affinity is not pH-dependent. Finally, we noted that OATP2B1-mediated transport of E-3-S, but not rosuvastatin, is pH sensitive in intestinal epithelial (Caco-2) cells. However, uptake of E-3-S and rosuvastatin by Caco-2 cells was diminished in the presence of proton ionophore. The present results indicate that OATP2B1 may be involved in the tissue uptake of rosuvastatin and fluvastatin, while OATP2B1 may play a significant role in the intestinal absorption of several statins due to their transporter affinity at acidic pH.

Culture Period-Dependent Changes in the Uptake of Transporter Substrates in Sandwich-Cultured Rat and Human Hepatocytes

Sandwich-cultured hepatocytes (SCH) are a useful tool for evaluating hepatobiliary drug transport in vitro. Some studies have investigated the in vitro-in vivo correlations of the biliary clearance of drugs using SCH. In most cases, the biliary clearance observed in vivo correlated well with the predicted clearance, but the predicted absolute values were underestimated when based on in vitro experiments with SCH. We hypothesized that the down-regulated function of uptake transporters is one of the causes of this underestimation. Therefore, the uptake of taurocholate, digoxin, pravastatin, and rosuvastatin was investigated in sandwich-cultured rat hepatocytes (SCRH) cultured for 5, 24, 48, and 96 h, and the predicted hepatic clearance from in vitro uptake clearance (CL(H, vitro)) was calculated with a dispersion model. In SCRH cultured for 96 h, the saturable uptake of taurocholate, digoxin, pravastatin, and rosuvastatin decreased to 7.5, 3.3, 64, and 23%, respectively, of their uptake in hepatocytes cultured for 5 h, and a better prediction of in vivo hepatic clearance (CL(H, vivo)) was achieved when based on CL(H, vitro) of 5-h-cultured hepatocytes. These results suggest that the uptake activity is considerably reduced in cell culture, even in a sandwich-culture format. In a similar study, we also examined taurocholate and rosuvastatin in sandwich-cultured human hepatocytes (SCHH). Unlike in SCRH, the saturable uptake of these compounds did not differ markedly in SCHH cultured for 5 or 96 h. Thus, the uptake activity in SCHH was maintained relatively well compared with that in SCRH.

The Role of OATP1B1 and BCRP in Pharmacokinetics and DDI of Novel Statins

The aim of this review is to provide useful information not only for studying the effect of OATP1B1 and/or BCRP gene mutation on pharmacokinetics of novle statins of pitavastatin and rosuvastatin but also for studying drug-drug interactions (DDI) between the novle statins and other substrates of OATP1B1 and/or BCRP. Intra- and inter-ethnic differences in pharmacokinetic profiles of clinically relevant drugs are important issues reported in many papers not only for scenes of appropriate drug used in clinical settings but also for those of the drug development. Pharmacogenomics is extremely useful for understanding these racial differences. Recent pharmacogenetics study have disclosed important roles of drug transporters in the pharmacokinetic (PK) profiles of some clinically relevant drugs. In this presentation, we introduce single nucleotide polymorphisms (SNPs) of OATP1B1 and BCRP and review the contribution of genetic polymorphisms of the transporters to the pharmacokinetics of dual substrates as pitavastatin and rosuvastatin from recent study. At the same time, the DDIs between pitavastatin or rosuvastatin and other drug have been extensively concerned because of inhibiting OATP1B1-mediated hepatic uptake or BCRP-mediated hepatic efflux of pitavastatin and rosuvastatin. This review summarized the current studies about the role of OATP1B1 and BCRP in DDIs between pitavastatin or rosuvastatin and other clinically relevant drugs. The role of OATP1B1 and BCRP gene mutation can affect the PK profiles of pitavastatin and rosuvastatin. The DDIs between the novle statins and other substrates of OATP1B1 or BCRP may occur and cause change in the pharmacokinetic of the novle statins.

Severe rhabdomyolysis due to rosuvastatin in a liver transplant subject with human immunodeficiency virus and immunosuppressive therapy-related dyslipidemia

Statins are relatively safe first-line agents to use in the setting of dyslipidemia associated with immunosuppressive therapy in subjects undergoing liver transplantation, and also in HIV-infected patients with dyslipidemia due to antiretroviral drugs, especially ritonavir-boosted protease inhibitors. Rosuvastatin, a new statin, has demonstrated higher potency than previously released statins and is not extensively metabolized by the liver P450 system; therefore, the probability of deleterious pharmacokinetic interactions with commonly used immunosuppressants and antiretroviral drugs is reduced. We present the first case of severe rhabdomyolysis in a liver transplant patient receiving rosuvastatin for the treatment of immunosuppressive therapy-related grade IV dyslipidemia, an HIV-infected subject on protease inhibitor-sparing HAART, that resolved after rosuvastatin withdrawal, probably related to interactions between calcineurin inhibitors and hepatic rosuvastatin uptake transporters such as organic anion transporting polypeptides (OATPs).

Genetic polymorphisms in Na+-taurocholate co-transporting polypeptide (NTCP) and ileal apical sodium-dependent bile acid transporter (ASBT) and ethnic comparisons of functional variants of NTCP among Asian populations

Genetic variants of Na+-taurocholate co-transporting polypeptide (NTCP; SLC10A1) and ileal apical sodium-dependent bile acid transporter (ASBT; SLC10A2), which greatly contribute to bile acid homeostasis, were extensively explored in the Korean population and functional variants of NTCP were compared among Asian populations.From direct DNA sequencing, six SNPs were identified in the SLC10A1 gene and 14 SNPs in the SLC10A2 gene. Three of seven coding variants were non-synonymous SNPs: two variants from SLC10A1 (A64T, S267F) and one from SLC10A2 (A171S). No linkage was analysed in the SLC10A1 gene because of low frequencies of genetic variants, and the SLC10A2 gene was composed of two separated linkage disequilibrium blocks contrary to the white population.The stably transfected NTCP-A64T variant showed significantly decreased uptakes of taurocholate and rosuvastatin compared with wild-type NTCP. The decreased taurocholate uptake and increased rosuvastatin uptake were shown in the NTCP-S267F variant. The allele frequencies of these functional variants were 1.0% and 3.1%, respectively, in a Korean population. However, NTCP-A64T was not found in Chinese and Vietnamese subjects. The frequency distribution of NTCP-S267F in Koreans was significantly lower than those in Chinese and Vietnamese populations.Our data suggest that NTCP-A64T and -S267F variants cause substrate-dependent functional change in vitro, and show ethnic difference in their allelic frequencies among Asian populations although the clinical relevance of these variants is remained to be evaluated.

Differential effect of genetic variants of Na+-taurocholate co-transporting polypeptide (NTCP) and organic anion-transporting polypeptide 1B1 (OATP1B1) on the uptake of HMG-CoA reductase inhibitors

The purpose of this study was to investigate the effect of genetic variations in organic anion-transporting polypeptide 1B1 (OATP1B1) and Na+/taurocholate co-transporting polypeptide (NTCP) on the uptake of various statins having different affinities for these transporters.The functional activities and simultaneous expression of NTCP and OATP1B1 were confirmed by the uptake of taurocholate and estrone-3-sulphate as representative substrates for NTCP and OATP1B1, respectively, and by an immunofluorescence analysis. The substrate specificities of NTCP and OATP1B1 for statins and the effects of genetic variations on the uptake of rosuvastatin, pitavastatin, and atorvastatin were measured.Based on the Km values and intrinsic clearances of the three statins, pitavastatin was taken up more efficiently than rosuvastatin and atorvastatin by OATP1B1. Consequently, the cellular accumulation of pitavastatin was modulated according to the genetic variation of OATP1B1 (OATP1B1*15), rather than NTCP*2. In contrast, NTCP*2 displayed greater transport of atorvastatin and rosuvastatin, compared with NTCP wild type. Thus, the measurements of decreased rosuvastatin and atorvastatin transport by OATP1B1*15 were confounded by the presence of NTCP and its genetic variant, NTCP*2.In conclusion, the functional consequences of genetic variants of NTCP and OATP1B1 may be different for various statins, depending on the substrate specificity of the OATP1B1 and NTCP transporters.

Rosuvastatin-Associated Adverse Effects and Drug-Drug Interactions in the Clinical Setting of Dyslipidemia

HMG-CoA reductase inhibitors (statins) are the mainstay in the pharmacologic management of dyslipidemia. Since they are widely prescribed, their safety remains an issue of concern. Rosuvastatin has been proven to be efficacious in improving serum lipid profiles. Recently published data from the JUPITER study confirmed the efficacy of this statin in primary prevention for older patients with multiple risk factors and evidence of inflammation. Rosuvastatin exhibits high hydrophilicity and hepatoselectivity, as well as low systemic bioavailability, while undergoing minimal metabolism via the cytochrome P450 system. Therefore, rosuvastatin has an interesting pharmacokinetic profile that is different from that of other statins. However, it remains to be established whether this may translate into a better safety profile and fewer drug-drug interactions for this statin compared with others. Herein, we review evidence with regard to the safety of this statin as well as its interactions with agents commonly prescribed in the clinical setting. As with other statins, rosuvastatin treatment is associated with relatively low rates of severe myopathy, rhabdomyolysis, and renal failure. Asymptomatic liver enzyme elevations occur with rosuvastatin at a similarly low incidence as with other statins. Rosuvastatin treatment has also been associated with adverse effects related to the gastrointestinal tract and central nervous system, which are also commonly observed with many other drugs. Proteinuria induced by rosuvastatin is likely to be associated with a statin-provoked inhibition of low-molecular-weight protein reabsorption by the renal tubules. Higher doses of rosuvastatin have been associated with cases of renal failure. Also, the co-administration of rosuvastatin with drugs that increase rosuvastatin blood levels may be deleterious for the kidney. Furthermore, rhabdomyolysis, considered a class effect of statins, is known to involve renal damage. Concerns have been raised by findings from the JUPITER study suggesting that rosuvastatin may slightly increase the incidence of physician-reported diabetes mellitus, as well as the levels of glycated hemoglobin in older patients with multiple risk factors and low-grade inflammation. Clinical trials proposed no increase in the incidence of neoplasias with rosuvastatin treatment compared with placebo. Drugs that antagonize organic anion transporter protein 1B1-mediated hepatic uptake of rosuvastatin are more likely to interact with this statin. Clinicians should be cautious when rosuvastatin is co-administered with vitamin K antagonists, cyclosporine (ciclosporin), gemfibrozil, and antiretroviral agents since a potential pharmacokinetic interaction with those drugs may increase the risk of toxicity. On the other hand, rosuvastatin combination treatment with fenofibrate, ezetimibe, omega-3-fatty acids, antifungal azoles, rifampin (rifampicin), or clopidogrel seems to be safe, as there is no evidence to support any pharmacokinetic or pharmacodynamic interaction of rosuvastatin with any of these drugs. Rosuvastatin therefore appears to be relatively safe and well tolerated, sharing the adverse effects that are considered class effects of statins. Practitioners of all medical practices should be alert when rosuvastatin is prescribed concomitantly with agents that may increase the risk of rosuvastatin-associated toxicity.

Involvement of Multiple Transporters in the Hepatobiliary Transport of Rosuvastatin

Rosuvastatin is an HMG-CoA reductase inhibitor and one of the most hydrophilic among the commercially available statins. It is efficiently accumulated in the liver and excreted into the bile in an unchanged form in rats, suggesting that hepatic transporters play a major role in its clearance. Therefore, we investigated the transporters responsible for the hepatic uptake and biliary excretion of rosuvastatin. Uptake studies revealed that human organic anion transporting polypeptide (OATP) 1B1, OATP1B3, and OATP2B1 accept rosuvastatin as a substrate. Among the OATP family transporters, OATP1B1 contributes predominantly to the hepatic uptake of rosuvastatin, as estimated with the previously published relative activity factor method, and OATP1B3 is also partly involved. Significant vectorial basal-to-apical transport was observed in OATP1B1/multidrug resistance-associated protein 2 (MRP2), OATP1B1/multidrug resistance protein 1 (MDR1), and OATP1B1/breast cancer resistance protein (BCRP) double transfectants compared with that in an OATP1B1 single transfectant or in vector-transfected control cells. The ATP-dependent uptake of rosuvastatin by human BCRP-expressing membrane vesicles was significantly higher than the uptake by green fluorescent protein-expressing control vesicles, suggesting that MRP2, MDR1, and BCRP can transport rosuvastatin. Under in vivo conditions, the biliary excretion clearances based on the intrahepatic concentration of the parent rosuvastatin in Eisai hyperbilirubinemic rats and Bcrp1 knockout mice were reduced to 53% and 12% of those in the control Sprague-Dawley rats and FVB mice, respectively, indicating that rat Mrp2 and mouse Bcrp1 are both partly involved in the biliary excretion of rosuvastatin. These results suggest that multiple transporters are involved in the hepatic uptake and efflux of rosuvastatin.

The Contribution of Organic Anion Transporters OAT1 and OAT3 to the Renal Uptake of Rosuvastatin

Rosuvastatin is a potent inhibitor of 3-hydroxy-3-methylglutaryl-CoA reductase and has been shown to be highly effective in reducing low-density lipoprotein cholesterol. Clinical trials have demonstrated that renal excretion and, in particular, tubular secretion, plays a role in rosuvastatin clearance. The aim of this study was to determine the involvement of the basolateral organic anion transporters, OAT1 and OAT3, in the renal uptake of rosuvastatin. Expression of human (h) OAT3 in Xenopus oocytes significantly increased the uptake of rosuvastatin above control levels (K(m) = 7.4 microM). In contrast hOAT1 did not mediate rosuvastatin uptake. Furthermore, hOAT3-mediated estrone-3-sulfate uptake could be inhibited, with a rank order of potency, by atorvastatin, rosuvastatin, simvastatin, and pravastatin, whereas hOAT1-mediated PAH uptake was only significantly inhibited by simvastatin. To estimate the contribution of hOAT3 to the overall renal uptake of rosuvastatin, a series of experiments were conducted using rat kidney slices. Rosuvastatin uptake in rat renal slices was abolished in the presence of the rat (r) Oat3-specific inhibitor benzylpenicillin, suggesting that rOat3 is responsible for the majority of rosuvastatin uptake across the basolateral membrane in rat kidney. From these findings, we can suggest that hOAT3 contributes to the renal uptake of rosuvastatin in humans.