Hepatic Drug Research Articles

Predictability of human pharmacokinetics of drugs that undergo hepatic organic anion transporting polypeptide (OATP)-mediated transport using single-species allometric scaling in chimeric mice with humanized liver: integration with hepatic drug metabolism

We previously reported a prediction method for human pharmacokinetics (PK) using single species allometric scaling (SSS) and the complex Dedrick plot in chimeric mice with humanized liver to predict the total clearance (CLt), distribution volumes in steady state (Vdss) and plasma concentration-time profiles of several drugs metabolized by cytochrome P450 (P450) and non-P450 enzymes. In the present study, we examined eight compounds (bosentan, cerivastatin, fluvastatin, pitavastatin, pravastatin, repaglinide, rosuvastatin, valsartan) as typical organic anion transporting polypeptide (OATP) substrates and six compounds metabolized by P450 and non-P450 enzymes to evaluate the predictability of CLt, Vdss and plasma concentration-time profiles after intravenous administration to chimeric mice. The predicted CLt and Vdss of drugs that undergo OATP-mediated uptake and P450/non-P450-mediated metabolism reflected the observed data from humans within a threefold error range. We also examined the possibility of predicting plasma concentration-time profiles of drugs that undergo OATP-mediated uptake using the complex Dedrick plot in chimeric mice. Most profiles could be superimposed with observed profiles from humans within a two- to threefold error range. PK prediction using SSS and the complex Dedrick plot in chimeric mice can be useful for evaluating drugs that undergo both OATP-mediated uptake and P450/non-P450-mediated metabolism.

Impact of Microbiome on Hepatic Metabolizing Enzymes and Transporters in Mice during Pregnancy.

The microbiome and pregnancy are known to alter drug disposition, yet the interplay of the two physiologic factors on the expression and/or activity of drug metabolizing enzymes and transporters (DMETs) is unknown. This study investigated the effects of microbiome on host hepatic DMETs in mice during pregnancy by comparing four groups of conventional (CV) and germ-free (GF) female mice and pregnancy status, namely, CV nonpregnant, GF non-pregnant, CV pregnant, and GF pregnant mice. Transcriptomic and targeted proteomics of hepatic DMETs were profiled by using multiomics. Plasma bile acid and steroid hormone levels were quantified by liquid chromatography tandem mass spectrometry. CYP3A activities were measured by mouse liver microsome incubations. The trend of pregnancy-induced changes in the expression or activity of hepatic DMETs in CV and GF mice was similar; however, the magnitude of change was noticeably different. For certain DMETs, pregnancy status had paradoxical effects on mRNA and protein expression in both CV and GF mice. For instance, the mRNA levels of Cyp3a11, the murine homolog of human CYP3A4, were decreased by 1.7-fold and 3.3-fold by pregnancy in CV and GF mice, respectively; however, the protein levels of CYP3A11 were increased similarly ∼twofold by pregnancy in both CV and GF mice. Microsome incubations revealed a marked induction of CYP3A activity by pregnancy that was 10-fold greater in CV mice than that in GF mice. This is the first study to show that the microbiome can alter the expression and/or activity of hepatic DMETs in pregnancy. SIGNIFICANCE STATEMENT: We demonstrated for the first time that microbiome and pregnancy can interplay to alter the expression and/or activity of hepatic drug metabolizing enzymes and transporters. Though the trend of pregnancy-induced changes in the expression or activity of hepatic drug metabolizing enzymes and transporters in conventional and germ-free mice was similar, the magnitude of change was noticeably different.

Induction of in vitro Metabolic Zonation in Primary Hepatocytes Requires Both Near-Physiological Oxygen Concentration and Flux.

Pre-clinical drug screening is an important step in assessing the metabolic effects and hepatic toxicity of new pharmaceutical compounds. However, due to the complexity of the liver microarchitecture, simplified in vitro models do not adequately reflect in vivo situations. Especially spatial heterogeneity, known as metabolic zonation, is often lost due to limitations introduced by typical culture conditions. By culturing primary rat hepatocytes in varied ambient oxygen levels on either gas-permeable or non-permeable culture plates, we highlight the importance of biomimetic oxygen supply for the targeted induction of zonation-like phenotypes. Resulting cellular profiles illustrate the effect of pericellular oxygen concentration and consumption rates on hepatic functionality in terms of zone-specific metabolism and β-catenin signaling. We show that modulation of ambient oxygen tension can partially induce metabolic zonation in vitro when considering high supply rates, leading to in vivo-like drug metabolism. However, when oxygen supply is limited, similar modulation instead triggers an ischemic reprogramming, resembling metabolic profiles of hepatocellular carcinoma and increasing susceptibility toward drug-induced injury. Application of this knowledge will allow for the development of more accurate drug screening models to better identify adverse effects in hepatic drug metabolism.

High fat diet significantly changed the global gene expression profile involved in hepatic drug metabolism and pharmacokinetic system in mice

BackgroundHigh fat diet impact transcription of hepatic genes responsible for drug metabolism and pharmacokinetics. Until now, researches just focused on a couple specific genes without a global profile showing. Age-dependent manner was also not noted well. This study aims to investigate the high fat diet effect on transcriptome of drug metabolism and pharmacokinetic system in mouse livers and show the age-dependent evidence.MethodsC57BL/6 male mice were used in this experiment. High fat diet was used to treat mice for 16 and 38 weeks. Serum total cholesterol, low density lipoprotein cholesterol, aspartate transaminase, and alanine transaminaselevels were measured. Meanwhile, Histology, RNA-Seq, RT-PCR analysis and fourteen major hepatic bile acids quantification were performed for the liver tissues. Data was mined at levels of genes, drug metabolism and pharmacokinetic sysem, and genome wide.ResultsTreatment with high fat diet for 38 weeks significantly increased levels of serum lipids as well as aspartate transaminase, and alanine transaminase. Meanwhile, lipid accumulation in livers was observed. At week 38 of the experiment, the profile of 612 genes involved in drug metabolism and pharmacokinetics was significantly changed, indicated by a heatmap visulization and a principal component analysis. In total 210 genes were significantly regulated. Cyp3a11, Cyp4a10, and Cyp4a14 were down-regulated by 10–35 folds, while these three genes also were highly expressed in the liver. High fat diet regulated 11% of genome-wide gene while 30% of genes involved in the hepatic drug metabolism and pharmacokinetic system. Genes, including Adh4, Aldh1b1, Cyp3a11, Cyp4a10, Cyp8b1, Fmo2, Gsta3, Nat8f1, Slc22a7, Slco1a4, Sult5a1, and Ugt1a9, were regulated by high fat diet as an aging-dependent manner. Bile acids homeostasis, in which many genes related to metabolism and transportation were enriched, was also changed by high fat diet with an aging-dependet manner. Expression of genes in drug metabolism and disposition system significantly correlated to serum lipid profiles, and frequently correlated with each other.ConclusionsHigh fat diet changed the global transcription profile of hepatic drug metabolism and pharmacokinetic system with a age-dependent manner.

Evaluating Lean Liver Volume as a Potential Scaler for In Vitro-In Vivo Extrapolation of Drug Clearance in Obesity Using the Model Drug Antipyrine.

In vitro-in vivo extrapolation (IVIVE) of hepatic drug clearance (CL) involves the scaling of hepatic intrinsic clearance (CLint,uH) by functional liver size, which is approximated by total liver volume (LV) as per the convention. However, in most overweight and obese patients, LV includes abnormal liver fat, which is not thought to contribute to drug elimination, thus overestimating drug CL. Therefore, lean liver volume (LLV) might be a more appropriate scaler of CLint,uH. The objective of this work was to assess the application of LLV in CL extrapolation in overweight and obese patients (BMI >25 kg/m2) using a model drug antipyrine. Recently, a model to predict LLV from patient sex, weight, and height was developed and evaluated. In order to assess the LLV model's use in IVIVE, a correlation-based analysis was conducted using antipyrine as an example drug. In the overweight group (BMI >25 kg/m2), LLV could describe 36% of the variation in antipyrine CL (R2 = 0.36), which was >2-fold higher than that was explained by LV (R2 = 0.17). In the normal-weight group (BMI ≤25 kg/m2), the coefficients of determination were 58% (R2 = 0.58) and 43% (R2= 0.43) for LLV and LV, respectively. The analysis indicates that LLV is potentially a more appropriate descriptor of functional liver size than LV, particularly in overweight individuals. Therefore, LLV has a potential application in IVIVE of CL in obesity.

A Physiology-Based Pharmacokinetic Framework to Support Drug Development and Dose Precision During Therapeutic Hypothermia in Neonates.

Therapeutic hypothermia (TH) is standard treatment for neonates (≥36 weeks) with perinatal asphyxia (PA) and hypoxic–ischemic encephalopathy. TH reduces mortality and neurodevelopmental disability due to reduced metabolic rate and decreased neuronal apoptosis. Since both hypothermia and PA influence physiology, they are expected to alter pharmacokinetics (PK). Tools for personalized dosing in this setting are lacking. A neonatal hypothermia physiology-based PK (PBPK) framework would enable precision dosing in the clinic. In this literature review, the stepwise approach, benefits and challenges to develop such a PBPK framework are covered. It hereby contributes to explore the impact of non-maturational PK covariates. First, the current evidence as well as knowledge gaps on the impact of PA and TH on drug absorption, distribution, metabolism and excretion in neonates is summarized. While reduced renal drug elimination is well-documented in neonates with PA undergoing hypothermia, knowledge of the impact on drug metabolism is limited. Second, a multidisciplinary approach to develop a neonatal hypothermia PBPK framework is presented. Insights on the effect of hypothermia on hepatic drug elimination can partly be generated from in vitro (human/animal) profiling of hepatic drug metabolizing enzymes and transporters. Also, endogenous biomarkers may be evaluated as surrogate for metabolic activity. To distinguish the impact of PA versus hypothermia on drug metabolism, in vivo neonatal animal data are needed. The conventional pig is a well-established model for PA and the neonatal Göttingen minipig should be further explored for PA under hypothermia conditions, as it is the most commonly used pig strain in nonclinical drug development. Finally, a strategy is proposed for establishing and fine-tuning compound-specific PBPK models for this application. Besides improvement of clinical exposure predictions of drugs used during hypothermia, the developed PBPK models can be applied in drug development. Add-on pharmacotherapies to further improve outcome in neonates undergoing hypothermia are under investigation, all in need for dosing guidance. Furthermore, the hypothermia PBPK framework can be used to develop temperature-driven PBPK models for other populations or indications. The applicability of the proposed workflow and the challenges in the development of the PBPK framework are illustrated for midazolam as model drug.

Methamphetamine administration increases hepatic CYP1A2 but not CYP3Aactivity in female guinea pigs.

Methamphetamine use has increased over the past decade and the first use of methamphetamine is most often when women are of reproductive age. Methamphetamine accumulates in the liver; however, little is known about the effect of methamphetamine use on hepatic drug metabolism. Methamphetamine was administered on 3 occassions to female Dunkin Hartley guinea pigs of reproductive age, mimicking recreational drug use. Low doses of test drugs caffeine and midazolam were administered after the third dose of methamphetamine to assess the functional activity of cytochrome P450 1A2 and 3A, respectively. Real-time quantitative polymerase chain reaction was used to quantify the mRNA expression of factors involved in glucocorticoid signalling, inflammation, oxidative stress and drug transporters. This study showed that methamphetamine administration decreased hepatic CYP1A2 mRNA expression, but increased CYP1A2 enzyme activity. Methamphetamine had no effect on CYP3A enzyme activity. In addition, we found that methamphetamine may also result in changes in glucocorticoid bioavailability, as we found a decrease in 11β-hydroxysteroid dehydrogenase 1 mRNA expression, which converts inactive cortisone into active cortisol. This study has shown that methamphetamine administration has the potential to alter drug metabolism via the CYP1A2 metabolic pathway in female guinea pigs. This may have clinical implications for drug dosing in female methamphetamine users of reproductive age.

Investigating the Role of Altered Systemic Albumin Concentration on the Disposition of Theophylline in Adult and Pediatric Patients with Asthma by Using the Physiologically Based Pharmacokinetic Approach.

Theophylline is commonly used for the treatment of asthma and has a low hepatic clearance. The changes in plasma albumin concentration occurring in asthma may affect the exposure of theophylline. The aim of the presented work was to predict theophylline pharmacokinetics (PK) after incorporating the changes in plasma albumin concentration occurring in patients with asthma into a physiologically based pharmacokinetic (PBPK) model to see whether these changes can affect the systemic theophylline concentrations in asthma. The PBPK model was developed following a systematic model building approach using Simcyp. The predictions were performed initially in healthy adults after intravenous and oral drug administration. Only when the developed adult PBPK model had adequately predicted theophylline PK in healthy adults, the changes in plasma albumin concentrations were incorporated into the model for predicting drug exposure in patients with asthma. After evaluation of the developed model in the adult population, it was scaled to children on physiologic basis. The model evaluation was performed by using visual predictive checks and comparison of ratio of observed and predicted (Robs/Pre) PK parameters along with their 2-fold error range. The developed PBPK model has effectively described theophylline PK in both healthy and diseased populations, as Robs/Pre for all the PK parameters were within the 2-fold error limit. The predictions in patients with asthma showed that there were no significant changes in PK parameters after incorporating the changes in serum albumin concentration. The mechanistic nature of the developed asthma-PBPK model can facilitate its extension to other drugs. SIGNIFICANCE STATEMENT: Exposure of a low hepatic clearance drug like theophylline may be susceptible to plasma albumin concentration changes that occur in asthma. These changes in systemic albumin concentrations can be incorporated into a physiologically based pharmacokinetic model to predict theophylline pharmacokinetics in adult and pediatric asthma populations. The presented work is focused on predicting theophylline absorption, distribution, metabolism, and elimination in adult and pediatric asthma populations after incorporating reported changes in serum albumin concentrations to see their impact on the systemic theophylline concentrations.

Are There Any Experimental Perfusion Data that Preferentially Support the Dispersion and Parallel-Tube Models over the Well-Stirred Model of Organ Elimination?

In reviewing previously published isolated perfused rat liver studies, we find no experimental data for high-clearance metabolized drugs that reasonably or unambiguously support preference for the dispersion and parallel-tube models versus the well-stirred model of organ elimination when only entering and exiting drug concentrations are available. It is likely that the investigators cited here may have been influenced by: 1) the unphysiologic aspects of the well-stirred model, which may have led them to undervalue the studies that directly test the various hepatic disposition models for high-clearance drugs (for which model differences are the greatest); 2) experimental assumptions made in the last century, which are no longer valid today, related to the predictability of in vivo outcomes from in vitro measures of drug elimination and the influence of albumin in hepatic drug uptake; and 3) a lack of critical review of previously reported experimental studies, resulting in inappropriate interpretation of the available experimental data. The number of papers investigating the theoretical aspects of the dispersion, parallel-tube, and well-stirred models of hepatic elimination greatly outnumber the papers that actually examine the experimental evidence available to substantiate these models. When all experimental studies that measure organ elimination using entering and exiting drug concentrations at steady state are critically reviewed, the simple but unphysiologic well-stirred model is the only model that can describe all trustworthy published available data. SIGNIFICANCE STATEMENT: Although the dispersion model of hepatic elimination more adequately reflects physiologic reality, there are no convincing experimental data that unambiguously favor this model. The well-stirred model can describe all well-designed perfusion studies with high-clearance drugs and nondrug substrates, but the field has not recognized this because of hesitation to accept a nonphysiologic model and flawed attempts to utilize in vitro-in vivo extrapolation approaches.

Pharmacomicrobiomics of Hepatic Drug Processing Genes During Pregnancy

At present, little is known about how gut microbiome and pregnancy interplay to regulate expression or the activities of drug processing genes (DPGs). The objective of this study was to investigate the effects of gut microbiome on host hepatic DPGs during pregnancy using conventional (CV) and germ‐free (GF) mice. Four groups of C57BL/6 female mice were used: CV non‐pregnant (CVNP, n=6), GF non‐pregnant (GFNP, n=6), CV pregnant (CVP, n=5), and GF pregnant (GFP, n=5) mice. Hepatic transcriptome and proteome for DPGs were profiled using multi‐omics approach. Plasma bile acids and steroid hormone levels were determined using LC‐MS/MS. Cyp activities were measured using hepatic microsome incubations. Overall, RNA‐seq analysis revealed a similar trend of gene regulation by pregnancy, but different magnitudes of change in hepatic DPGs, in CV and GF mice. Of note, the Cyp3a11 mRNA levels were decreased 1.7‐fold and 3.2‐fold by pregnancy in CV and GF mice, respectively. On the contrary, the Cyp3a11 protein abundance was increased 1.2‐fold and 1.6‐fold by pregnancy in CV and GF mice, respectively. The Cyp3a activity was also significantly induced by pregnancy in CV and GF mice; however, the magnitude of induction in CV mice was >5‐fold greater than that in GF mice. Plasma bile acid and steroid hormone levels were significantly impacted by microbiome and pregnancy‐status, respectively, which may contribute to the differential effects of pregnancy in CV and GF mice. This is the first study to demonstrate that the gut microbiome may play a role in altering hepatic drug disposition in pregnancy.Support or Funding InformationThis project was supported by the University of Washington Drug Metabolism, Transport and Pharmacogenomics Research Program (DMTPR)

Janus kinase-dependent regulation of drug detoxifying protein expression by interleukin-22 in human hepatic cells

Interleukin (IL)-22 is a cytokine up-regulated in inflammatory situations and known to exert various hepatic effects. The potential impact of IL-22 towards liver drug detoxifying proteins remains nevertheless unknown, but may be important to determine owing to the well-established alterations of liver detoxification occuring during inflammation. The present study was therefore designed to analyze the effects of IL-22 towards drug metabolizing enzyme and drug transporter expression and activity in cultured human hepatic cells. Exposure of differentiated hepatoma HepaRG cells or primary human hepatocytes to 10 ng/mL IL-22 was found to repress mRNA expression of cytochrome P-450 (CYP) 1A2, CYP3A4, CYP2B6 and CYP2C9 and of the sinusoidal sodium-taurocholate co-transporting polypeptide (NTCP); such IL-22 effects were concentration-dependent for CYP3A4 (IC50 = 1.7 ng/mL), CYP2B6 (IC50 = 0.9 ng/mL) and NTCP (IC50 = 1.8 ng/mL). Activity of CYP1A2 (phenacetin O-deethylation), CYP3A4 (midazolam hydroxylation) and CYP2B6 (bupropion hydroxylation), as well as that of NTCP (taurocholate uptake) were concomitantly decreased in IL-22-treated HepaRG cells; by contrast, activity of organic anion transporter polypeptides (OATPs) (estrone-3-sulfate uptake) and of organic cation transporter (OCT) 1 (tetra-ethylammonium uptake) remained unchanged. IL-22 was next found to activate the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) 3 pathway, whose inhibition by the JAK inhibitor ruxolitinib fully prevented the IL-22-mediated CYP3A4, CYP2B6 and NTCP repression in HepaRG cells. This JAK-dependent down-regulation of hepatic drug detoxifying proteins, notably of CYPs, by IL-22 may contribute to alteration of pharmacokinetics in patients suffering from acute and chronic inflammatory diseases and may be the source of drug-drug interactions.

DNA methylation and histone acetylation changes to cytochrome P450 2E1 regulation in normal aging and impact on rates of drug metabolism in the liver.

Aging is associated with reduced liver function that may increase the risk for adverse drug reactions in older adults. We hypothesized that age-related changes to epigenetic regulation of genes involved in drug metabolism may contribute to this effect. We reviewed published epigenome-wide studies of human blood and identified the cytochrome P450 2E1 (CYP2E1) gene as a top locus exhibiting epigenetic changes with age. To investigate potential functional changes with age in the liver, the primary organ of drug metabolism, we obtained liver tissue from mice aged 4-32months from the National Institute on Aging. We assayed global DNA methylation (5-methylcytosine, 5mC), hydroxymethylation (5-hydroxymethylcytosine, 5hmC), and locus-specific 5mC and histone acetylation changes around mouse Cyp2e1. The mouse livers exhibit significant global decreases in 5mC and 5hmC with age. Furthermore, 5mC significantly increased with age at two regulatory regions of Cyp2e1 in tandem with decreases in its gene and protein expressions. H3K9ac levels also changed with age at both regulatory regions of Cyp2e1 investigated, while H3K27ac did not. To test if these epigenetic changes are associated with varying rates of drug metabolism, we assayed clearance of the CYP2E1-specific probe drug chlorzoxazone in microsome extracts from the same livers. CYP2E1 intrinsic clearance is associated with DNA methylation and H3K9ac levels at the Cyp2e1 locus but not with chronological age. This suggests that age-related epigenetic changes may influence rates of hepatic drug metabolism. In the future, epigenetic biomarkers could prove useful to guide dosing regimens in older adults.

Consensus on the diagnosis and treatment of hepatic fibrosis (2019).

Hepatic fibrosis is a reparative response of diffuse over-deposition and abnormal distribution of extracellular matrix (collagen, glycoprotein and proteoglycans) after exposure to various kinds of liver injuries, and is a key step in the developmental process of various chronic liver diseases leading to cirrhosis. Recently, many advances in our understanding of hepatic fibrosis have been obtained through basic and clinical research. Therefore, this consensus summarizes and offers 15 evidence-based recommendations on the diagnosis and evaluation of hepatic fibrosis, its treatment, drug development and applications.

Study the Response of Qurevo (Ombitasvir, Paritaprevir and Ritonavir) in End Stage Renal Disease Patients with Hepatitis C Virus

Abstract Background According to the WHO there are 185 million people infected with HCV in the world.Egypt has the highest prevalence of hepatitis C virus (HCV) in the world reaching 13% equating to an estimated 12 million Egyptians . HCV is one of the main causes of liver cirrhosis and hepatocellular carcinoma.HCV can develop kidney disease because of extrahepatic manifestations of HCV or as a disease process independent of the HCV infection.In addition, hemodialysis has been a risk factor for acquiring HCV infection. The prevalence of HCV infection is high in patients with ESRD, on hemodialysis ranges from 6% to 60% in different parts of the world. Several studies show that patients on hemodialysis have an increased overall mortality risk if they have chronic HCV when compared with those on dialysis who do not have HCV. Antiviral treatment in CKD patients can be complicated because many of the agents used for anti-HCV therapy can accumulate to toxic levels in the setting of renal impairment. Treatment of HCV compensated cirrhosis with the new DAA therapy Qurevo “ombitasvir/paritaprevir/ritonavir” with ribavirin in ESRD was approved in many countries. Aim of the study To evaluate the efficacy and safety of Qurevo/Ribavirin regimen in ESRD Egyptian patients who are infected with hepatitis C virus (HCV) . Patients and Methods A prospective cohort study evaluated the outcome of 12-week ombitasvir (NS5A inhibitor)/paritaprevir (NS3/4A protease inhibitor)/ritonavir with ribavirin combination therapy for 50 ESRD patients with HCV at the hepatic virology clinic at Ain Shams University hospital over a period of 15 months (from December 2016 to February 2018). The primary endpoint was sustained virologic response 12 weeks after therapy (SVR12). Results 50 ESRD patients with a mean age of 51.4 years, range from 23-77 years were enrolled.The SVR12 rate was 96% (48/50); 2 patients had virologic failure. As regards adverse events, the most frequent was fatigue/asthenia in 44 patients (88%) and worsening anemia (Hb dropped to < 10 g/dl) in 42 patients (84%). GIT upset occurred in 10 patients (20%), sleep disorders in 8 patients (16%), decreased appetite in 8 patients (16%),respiratory distress in 6 patients (12%), headache, dizziness in 6 patients(12%). Muscle spasms in 4 patients (8%). Itching(pruritis) occurred in 3 patients(6%).2 patients (4%) were non-responders to treatment and another 2 (4%) were relapsers.Death occurred in 4 patients (8%) due to myocardial infarction, pulmonary edema, severe hypotension on hemodialysis sessions, shock due to blood loss in retroperitoneal hematoma following peritoneal dialysis. Hepatic decompensation, hypersenisitivity (angioedema), teratogenicity and drug interactions did not occur in any patient (0%).Other events occurred in 11 patients (22%). They were parenchymal liver changes in ultrasound at the end of therapy after being normal before therapy (in 3 patients), thrombocytopenia, increased alkaline phosphatase, hiccough, deterioration of hypertension, urinary tract infection, lower limb cellulitis, vaginal bleeding, chest infection(in 1 patient each). SVR12 was achieved in 100% of patients who had to stop or modify ribavirin dose;this means that Ribavirin absence didn’t affect the sustained viral response in these patients. Conclusion Our results confirm the efficacy of Qurevo “ombitasvir/paritaprevir/ritonavir” with Ribavirin combination therapy in ESRD patients with HCV infection, with anemia as the most frequent adverse event.

Fine-Needle Aspiration for the Evaluation of Hepatic Pharmacokinetics of Vaniprevir: A Randomized Trial in Patients With Hepatitis C Virus Infection.

Fine-needle aspiration (FNA) for serial hepatic sampling may be an efficient and less invasive alternative to core needle biopsy (CNB), the current standard for liver tissue sampling. In this randomized, open-label trial in 31 participants with hepatitis C virus genotype 1 infection (NCT01678131/Merck protocol PN048), we evaluated the feasibility of using FNA to obtain human liver tissue samples appropriate for measuring hepatic pharmacokinetics (PK), using vaniprevir as a tool compound. The primary end point was successful retrieval of liver tissue specimens with measurable vaniprevir concentrations at two of three specified FNA time points. Twenty-nine patients met the primary end point and, therefore, were included in the PK analyses. Hepatic vaniprevir concentrations obtained with FNA were consistent with known vaniprevir PK properties. The shape of liver FNA and CNB concentration-time profiles were comparable. In conclusion, FNA may be effective for serial tissue sampling to assess hepatic drug exposure in patients with liver disease.

Clinically Relevant OATP2B1 Inhibitors in Marketed Drug Space.

OATP2B1 is an intestinal and hepatic drug uptake transporter. Intestinal OATP2B1 has been elucidated as the mechanism of unexpected clinical drug-drug interactions (DDIs), where drug exposure was unexpectedly decreased with unchanged half-life. Hepatic OATP2B1 may be an understudied clinical DDI mechanism. The aim of the present work was to understand the prevalence of clinically relevant intestinal and hepatic OATP2B1 inhibitors in marketed drug space. HEK293 cells stably overexpressing human OATP2B1 or vector control were generated and cultured for 72 h in a 96-well format. OATP2B1-mediated uptake of dibromofluorescein (DBF) was found to be optimal at 10 μM concentration and 30 min incubation time. A total of 294 drugs (top 300 marketed drugs, excluding biologics and restricted drugs, supplemented with ∼100 small-molecule drugs) were screened for OATP2B1 inhibition at 10 μM. Drugs demonstrating ≥50% inhibition in this screen were advanced for IC50 determination, which was extrapolated to clinical intestinal and hepatic OATP2B1 inhibition as per 2017 FDA DDI guidance. Of the 294 drugs screened, 67 elicited ≥50% inhibition of OATP2B1-mediated DBF uptake at 10 μM screening concentration. For the 67 drugs flagged in the single-concentration inhibition screen, upon evaluation of a full concentration range, IC50 values could be determined for 58 drugs. OATP2B1 IC50 values established for these 58 drugs were extrapolated as potentially clinically relevant at the intestinal level for 38 orally administered drugs (Igut/IC50 ≥ 10), and 17 were flagged as potential clinical inhibitors of hepatic OATP2B1 uptake (1 + Iin,max,u/IC50 ≥ 1.1). This analysis of 294 drugs demonstrated prevalence of clinically relevant intestinal and hepatic OATP2B1 inhibitors to be 13 and 6%, respectively. As OATP2B1-inhibitor drugs are not exceedingly rare, these results suggest that clinical OATP2B1 DDIs have been rarely observed because OATP2B1 is uncommonly the predominant determinant of drug disposition.

Türkiye'de Hepatik Granülomlarin Prevalansı ve Etiyolojisi: Bir Sistematik Derleme

Objective: Hepatic granulomas (HGs) are seen in 2- 4% of liver biopsies and the etiology is heterogeneous including liver involvement in systemic immunologic disorders and infectious diseases, primary hepatic diseases, drug hepatotoxicity, foreign bodies, and reaction to neoplastic disease. Common etiologies are primary biliary cholangitis (PBC) and sarcoidosis in the Western world, while infections especially tuberculosis (TB) preclude in the Eastern countries. In Turkey, HGs have been reported in 2-5% of liver biopsies and the etiology includes both infections and non-infectious diseases. In this review, we aimed to determine the prevalence and etiology of HGs in Turkey. Material and Methods: A search of Pubmed, Scopus and Science Citation Index and national databses (including Tübitak Ulakbim, Türkmedline, and Türk Atıf Dizini) was done and 60 reports were reached. Four studies from Turkey dedicated to describe the rate of HGs and their etiology were determined. Results: The rate of HGs is 2.27% (208/9164). Infections as a group (TB, hydatid disease, HCV, brucellosis, fascioliasis, typhoid fever, fungal infection, HBV, actinomycosis, yersiniosis, leishmaniasis, and infectious mononucleosis) were the etiology in 38.4%. PBC was the leading etiology, followed by sarcoidosis, TB, and hydatid disease. Beside the dedicated HG series, 11 series from Turkey included cases with HGs and 45 papers described 52 case reports with HGs. Conclusion: HGs are seen in 2.3% of the liver biopsies in Turkey. The infections still represent the leading etiology and among them, TB appears the commonest one. When the cases are evaluated individually, PBC is the leading etiology. Infections are followed by PBC and sarcoidosis, which are main two etiologies of HGs in the world. The local and regional epidemiology of certain infectious diseases, particularly TB determines the etiologic distribution of HGs.

P242 - In vitro functional characterization of rare genetic variants in hepatic bile acid and drug transporter NTCP

P242 - In vitro functional characterization of rare genetic variants in hepatic bile acid and drug transporter NTCP

Predicting human tissue exposures to xenobiotics using a bottom-up physiologically-based biokinetic model

Advances in physiologically-based biokinetic (PBK) modelling, in vitro-to-in vivo extrapolation (IVIVE) methodologies, and development of permeability-limited biokinetic models have allowed predictions of tissue drug concentrations without utilizing in vivo animal or human data. However, there is a lack of in vivo human tissue concentrations to validate these models. Herein, we validated the performance of our previously published bottom-up rosuvastatin (RSV) PBK model with clinical data from a recently published study that made use of positron emission tomography (PET) imaging to quantify the hepatic concentrations of [11C]RSV drug-drug interaction (DDI) with cyclosporine A (CsA). Simulated RSV area under the plasma concentration-time curve (AUC0h-t) and maximum plasma concentration (Cmax) before and after DDI were within 1.5-fold of the observed data. Simulated AUC0-30min and Cmax ratios in the DDI setting matched the observed ratios closely (within 1.1-fold). To predict RSV hepatic concentrations, the model inputs were modified to account for RSV in the bile canaliculi after biliary excretion. The model recapitulated the observed hepatic concentrations before DDI and the decrease in hepatic concentrations after DDI. Simulated area under the liver concentration-time curve (AUC0-30min,liver), maximum liver concentration (Cmax,liver), AUC0-30min,liver ratio and Cmax,liver ratios were predicted within 1.5-fold of the observed data. In summary, we validated the ability of bottom-up PBK modelling to predict RSV hepatic concentrations with and without DDI with CsA. Our findings confirm the importance to account for drug distributed within the bile canaliculi for accurate prediction of hepatic tissue drug levels when compared against in vivo liver PET scan data.

P112 - Primary human hepatocyte 3D spheroids for studying hepatic function and drug metabolism

P112 - Primary human hepatocyte 3D spheroids for studying hepatic function and drug metabolism