Hepatic Drug Research Articles

Intracellular trafficking of bio-nanocapsule–liposome complex: Identification of fusogenic activity in the pre-S1 region of hepatitis B virus surface antigen L protein

Bio-nanocapsules (BNCs) are a hollow nanoparticle consisting of about 100-nm liposome (LP) embedding about 110 molecules of hepatitis B virus (HBV) surface antigen (HBsAg) L protein as a transmembrane protein. Owing to the human hepatocyte-recognizing domains on the N-terminal region (pre-S1 region), BNCs have recently been shown to attach and enter into human hepatic cells using the early infection mechanism of HBV. Since BNCs could form a complex with an LP containing various drugs and genes, BNC–LP complexes have been used as a human hepatic cell-specific drug and gene-delivery system in vitro and in vivo. However, the role of BNCs in cell entry and intracellular trafficking of payloads in BNC–LP complexes has not been fully elucidated. In this study, we demonstrate that low pH-dependent fusogenic activity resides in the N-terminal part of pre-S1 region (NPLGFFPDHQLDPAFG), of which the first FF residues are essential for the activity, and which facilitates membrane fusion between LPs in vitro. Moreover, BNC–LP complexes can bind human hepatic cells specifically, enter into the cells via clathrin-mediated endocytosis, and release their payloads mostly into the cytoplasm. Taken together, the BNC portion of BNC–LP complexes can induce membrane fusion between LPs and endosomal membranes under low pH conditions, and thereby facilitate the endosomal escape of payloads. Furthermore, the fusogenic domain of the pre-S1 region of HBsAg L protein may play a pivotal role in the intracellular trafficking of not only BNC–LP complexes but also of HBV.

Mechanism of Altered Metformin Distribution in Nonalcoholic Steatohepatitis.

Metformin is an antihyperglycemic drug that is widely prescribed for type 2 diabetes mellitus and is currently being investigated for the treatment of nonalcoholic steatohepatitis (NASH). NASH is known to alter hepatic membrane transporter expression and drug disposition similarly in humans and rodent models of NASH. Metformin is almost exclusively eliminated through the kidney primarily through active secretion mediated by Oct1, Oct2, and Mate1. The purpose of this study was to determine how NASH affects kidney transporter expression and metformin pharmacokinetics. A single oral dose of [14C]metformin was administered to C57BL/6J (wild type [WT]) and diabetic ob/ob mice fed either a control diet or a methionine- and choline-deficient (MCD) diet. Metformin plasma concentrations were slightly increased in the WT/MCD and ob/control groups, whereas plasma concentrations were 4.8-fold higher in ob/MCD mice compared with WT/control. The MCD diet significantly increased plasma half-life and mean residence time and correspondingly decreased oral clearance in both genotypes. These changes in disposition were caused by ob/ob- and MCD diet–specific decreases in the kidney mRNA expression of Oct2 and Mate1, whereas Oct1 mRNA expression was only decreased in ob/MCD mice. These results indicate that the diabetic ob/ob genotype and the MCD disease model alter kidney transporter expression and alter the pharmacokinetics of metformin, potentially increasing the risk of drug toxicity.

Regulation of gene expression by CAR: an update.

The constitutive androstane receptor (CAR), a member of the nuclear receptor superfamily, is a well-known xenosensor that regulates hepatic drug metabolism and detoxification. CAR activation can be elicited by a large variety of xenobiotics, including phenobarbital (PB) which is not a directly binding CAR ligand. The mechanism of CAR activation is complex and involves translocation from the cytoplasm into the nucleus, followed by further activation steps in the nucleus. Recently, epidermal growth factor receptor (EGFR) has been identified as a PB-responsive receptor, and PB activates CAR by inhibiting the EGFR signaling. In addition to regulation of drug metabolism, activation of CAR has multiple biological end points such as modulation of xenobiotic-elicited liver injury, and the role of CAR in endobiotic functions such as glucose metabolism and cholesterol homeostasis is increasingly recognized. Thus, investigations on the molecular mechanism of CAR activation are critical for the real understanding of CAR-mediated processes. Here, we summarize the current understanding of mechanisms by which CAR activators regulate gene expression through cellular signaling pathways and the roles of CAR on xenobiotic-elicited hepatocellular carcinoma, liver injury, glucose metabolism and cholesterol homeostasis.

RNA-Seq Quantification of Hepatic Drug Processing Genes in Germ-Free Mice.

Intestinal bacteria have been shown to be important in regulating host intermediary metabolism and contributing to obesity. However, relatively less is known about the effect of intestinal bacteria on the expression of hepatic drug-processing genes in the host. This study characterizes the expression of hepatic drug-processing genes in germ-free (GF) mice using RNA-Seq. Total RNA were isolated from the livers of adult male conventional and GF C57BL/6J mice (n = 3 per group). In the livers of GF mice, the mRNA of the aryl hydrocarbon receptor target gene Cyp1a2 was increased 51%, and the mRNA of the peroxisome proliferator-activated receptor α (PPARα) target gene Cyp4a14 was increased 202%. Conversely, the mRNA of the constitutive androstane receptor (CAR) target gene Cyp2b10 was decreased 57%, and the mRNA of the pregnane X receptor target gene Cyp3a11 was decreased 87% in GF mice. Although other non-Cyp phase-1 enzymes in the livers of GF mice were only moderately affected, there was a marked down-regulation in the phase-2 enzymes glutathione S-transferases p1 and p2, as well as a marked up-regulation in the major bile acid transporters Na(+)-taurocholate cotransporting polypeptide and organic anion-transporting polypeptide 1b2, and the cholesterol transporter ATP-binding cassette transporter Abcg5/Abcg8. This study demonstrates that intestinal bacteria regulate the expression of a large number of drug-processing genes, which suggests that intestinal bacteria are responsible for some individual differences in drug responses.

Discovery of Novel Liver-Stage Antimalarials through Quantum Similarity.

Without quantum theory any understanding of molecular interactions is incomplete. In principal, chemistry, and even biology, can be fully derived from non-relativistic quantum mechanics. In practice, conventional quantum chemical calculations are computationally too intensive and time consuming to be useful for drug discovery on more than a limited basis. A previously described, original, quantum-based computational process for drug discovery and design bridges this gap between theory and practice, and allows the application of quantum methods to large-scale in silico identification of active compounds. Here, we show the results of this quantum-similarity approach applied to the discovery of novel liver-stage antimalarials. Testing of only five of the model-predicted compounds in vitro and in vivo hepatic stage drug inhibition assays with P. berghei identified four novel chemical structures representing three separate quantum classes of liver-stage antimalarials. All four compounds inhibited liver-stage Plasmodium as a single oral dose in the quantitative PCR mouse liver-stage sporozoites-challenge model. One of the newly identified compounds, cethromycin [ABT-773], a macrolide-quinoline hybrid, is a drug with an extensive (over 5,000 people) safety profile warranting its exploitation as a new weapon for the current effort of malaria eradication. The results of our molecular modeling exceed current state-of-the-art computational methods. Drug discovery through quantum similarity is data-driven, agnostic to any particular target or disease process that can evaluate multiple phenotypic, target-specific, or co-crystal structural data. This allows the incorporation of additional pharmacological requirements, as well as rapid exploration of novel chemical spaces for therapeutic applications.

Bromocriptine tablet of self-microemulsifying system adsorbed onto porous carrier to stimulate lipoproteins secretion for brain cellular uptake

Both low solubility and high hepatic metabolism cause low oral bioavailability of bromocriptine mesylate (BM) leading to very low drug amount in brain. Self-microemulsion (SME) tablets were developed to improve solubility, stimulate lipoprotein synthesis to promote lymphatic transport, avoid hepatic metabolism and target drug to brain. SME liquid containing castor oil, Tween® 80 and Cremophor® EL was prepared and then adsorbed onto solid carries, Aerosil®200, Aeroperl®300 or NeusilinUS2®, yielding SME powders. The optimal ratios of SME liquid to carriers determined from flowability and scanning electron photomicrographs before tableting were 1.5:1, 2:1 and 2.5:1 for Aerosil®200, Aeroperl®300 and NeusilinUS2®, respectively. Only Aeroperl®300 SME tablet had comparable dissolution to BM commercial tablet. From in vitro study in Caco-2 cells, fluorescein loaded SME tablet showed higher uptake than fluorescein loaded in either oil or surfactant. Although significantly lower amount of drug was permeated from SME tablet than from commercial tablet, higher drug uptake was obviously observed (P<0.05). In addition, higher lipoprotein synthesis expressing as content of apolipoprotein B (apo-B) found in secreted chylomicron resulted in higher drug uptake in co-culture of brain endothelial cells (bEnd.3) and astrocytes (CTX TNA2) from drug loaded SME tablet when compared to commercial tablet (P<0.05) due to binding of apo-B to LDL receptors expressed on the surface of endothelial cells. Therefore, tablet of SME adsorbed onto porous carrier potentially delivered BM to brain via lymphatic transport by increasing the lipoprotein synthesis.

Effects of Trichostatin A on drug uptake transporters in primary rat hepatocyte cultures.

The present study was set up to investigate the effects of Trichostatin A (TSA), a prototypical epigenetic modifier, on the expression and activity of hepatic drug uptake transporters in primary cultured rat hepatocytes. To this end, the expression of the sinusoidal transporters sodium-dependent taurocholate cotransporting polypeptide (Ntcp) and organic anion transporting polypeptide 4 (Oatp4) was monitored by real-time quantitative reverse transcriptase polymerase chain reaction analysis and immunoblotting. The activity of the uptake transporters was analyzed using radiolabeled substrates and chemical inhibitors. Downregulation of the expression and activity of Oatp4 and Ntcp was observed as a function of the cultivation time and could not be counteracted by TSA. In conclusion, the epigenetic modifier TSA does not seem to exert a positive effect on the expression and activity of the investigated uptake transporters in primary rat hepatocyte cultures.

Ethnic variability in the expression of hepatic drug transporters: absolute quantification by an optimized targeted quantitative proteomic approach.

Hepatic OATPs 1B1, 1B3 and 2B1, as well as P-gp, play important roles in regulating liver uptake and biliary excretion of drugs. The intrinsic ethnic variability in OATP1B1-mediated hepatic uptake of statins has been proposed to underlie the ethnic variability in plasma exposures of statins between Caucasians and Asians. Using a targeted quantitative proteomic approach, we determined hepatic protein concentrations of OATP1B1, OATP1B3, OATP2B1, P-gp, and PMCA4 (a housekeeping protein) in a panel of human livers (n = 141) and compared protein expression across Caucasian, Asian, African-American, and unidentified donors. Using an optimized protocol that included sodium deoxycholate as a membrane protein solubilizer, the hepatic protein expression levels (mean ± S.D.) of these transporters across all livers were determined to be 15.0 ± 6.0, 16.1 ± 8.1, 4.1 ± 1.3, 0.6 ± 0.2, and 2.4 ± 1.0 fmol/μg of total membrane protein, respectively. The scaling factor was 3.5 mg of total membrane protein in 100 mg of wet liver tissue. OATP1B1 protein expression was significantly associated with the c.388A>G (rs2306283, N130D) single nucleotide polymorphism. When compared across ethnicity, the hepatic expression levels of OATP1B1 and OATP1B3 were unexpectedly higher in Asians relative to Caucasians, suggesting that hepatic OATP expression alone does not explain the increased systemic statin levels in Asians compared with Caucasians. These findings may help improve physiologically based pharmacokinetic modeling to predict statin pharmacokinetic profiles and enable extrapolation of pharmacokinetic data of OATP substrates across ethnic groups.

Quantification of proteins by flow cytometry: Quantification of human hepatic transporter P-gp and OATP1B1 using flow cytometry and mass spectrometry

Flow cytometry is a powerful tool for the quantitation of fluorescence and is proven to be able to correlate the fluorescence intensity to the number of protein on cells surface. Mass spectroscopy can also be used to determine the number of proteins per cell. Here we have developed two methods, using flow cytometry and mass spectroscopy to quantify number of transporters in human cells. These two approaches were then used to analyse the same samples so that a direct comparison could be made.Transporters have a major impact on the behaviour of a diverse number of drugs in human systems. While active uptake studies by transmembrane protein transporters using model substrates are routinely undertaken in human cell lines and hepatocytes as part of drug discovery and development, the interpretation of these results is currently limited by the inability to quantify the number of transporters present in the test samples.Here we provide a flow cytometric method for accurate quantification of transporter levels both on the cell surface and within the cell, and compare this to a quantitative mass spectrometric approach. Two transporters were selected for the study: OATP1B1 (also known as SLCO1B1, LST-1, OATP-C, OATP2) due to its important role in hepatic drug uptake and elimination; P-gp (also known as P-glycoprotein, MDR1, ABCB1) as a well characterised system and due to its potential impact on oral bioavailability, biliary and renal clearance, and brain penetration of drugs that are substrates for this transporter. In all cases the mass spectrometric method gave higher levels than the flow cytometry method. However, the two methods showed very similar trends in the relative ratios of both transporters in the hepatocyte samples investigated. The P-gp antibody allowed quantitative discrimination between externally facing transporters located in the cytoplasmic membrane and the total number of transporters on and in the cell. The proportion of externally facing transporter varied considerably in the four hepatocyte samples analysed, ranging from only 6% to 35% of intact and viable cells. The sample with only 6% externally facing transporter was further analysed by confocal microscopy which qualitatively confirmed the low level of transporter in the membrane and the large internal population. Here we prove that flow cytometry is an important tool for future protein analysis as it can not only quantify the number of proteins that a cell express but also identify the number of proteins on the surface and it is easy to apply for routine assays.

Use of Three-Compartment Physiologically Based Pharmacokinetic Modeling to Predict Hepatic Blood Levels of Fluvoxamine Relevant for Drug-Drug Interactions

Using a three-compartment physiologically based pharmacokinetic (PBPK) model and a tube model for hepatic extraction kinetics, equations for calculating blood drug levels (Cb s) and hepatic blood drug levels (Chb s, proportional to actual hepatic drug levels), were derived mathematically. Assuming the actual values for total body clearance (CLtot ), oral bioavailability (F), and steady-state distribution volume (Vdss ), Cb s, and Chb s after intravenous and oral administration of fluvoxamine (strong perpetrator in drug-drug interactions, DDIs), propranolol, imipramine, and tacrine were simulated. Values for Cb s corresponded to the actual values for all tested drugs, and mean Chb and maximal Chb -to-maximal Cb ratio predicted for oral fluvoxamine administration (50 mg twice-a-day administration) were nearly 100 nM and 2.3, respectively, which would be useful for the predictions of the DDIs caused by fluvoxamine. Fluvoxamine and tacrine are known to exhibit relatively large F values despite having CLtot similar to or larger than hepatic blood flow, which may be because of the high liver uptake (almost 0.6) upon intravenous administration. The present method is thus considered to be more predictive of the Chb for perpetrators of DDIs than other methods.

Nuclear Receptor PXR; a Novel Glucose Sensor That Regulates Hepatic Gluconeogenesis

Pregnane X receptor (PXR) was originally characterized as a ligand-activated transcription factor that regulates hepatic drug metabolism and deposition. Here we have determined that PXR as a low glucose response regulator that increases hepatic gluconeogenesis by activating the phosphoenolpyruvate carboxykinase 1 (Pepck1) and glucose 6 phosphatase (G6Pase) genes in the livers of fasting mice. Serum/glucocorticoid regulated kinase 2 (SGK2) was found to regulate the PXR-mediated activation of these genes. Phosphorylated SGK2 at Thr193 repressed the Pepck1 gene by binding to proximal promoter region (-298/-180) of the Pepck1 gene in livers of mice under fed condition. In response to fasting, SGK2 was dephosphorylated and dissociated from the promoter to activate the Pepck1 gene only in livers of control mice but not of PXR knockout mice. By utilizing human hepatoma HepG2 cell-derived ShP51 cells that stably express human PXR, we confirmed that low glucose, but neither insulin nor glucagon, was the cell signal that dephosphorylated SGK2 at Thr193 only when PXR was present. As to the mechanism of Thr193 dephosphorylation, PXR scaffolds protein phosphatase 2C to stimulate it in response to low glucose. Thus, the novel glucose-PXR-SGK2 pathway is a novel physiological signaling that increases hepatic gluconeogenesis in response to fasting. Consistent with the lack of this signaling, fasting PXR knockout mice developed hepatic steatosis as observed in PEPCK1 and G6Pase knockout mice (She P et al., 2000, Mutel E et al., 2011).

Identification of MicroRNAs Involved in the Regulation of Human UGT1A, UGT2B7 and UGT2B15 Gene Expression

BackgroundThe human UGT enzymes are responsible for the glucuronidation and elimination of a large number of clinically important drugs. Large interindividual variations of human hepatic drug glucuronidation have been observed in vitro, which cannot be entirely explained by the mechanisms studied so far. MicroRNAs (miRs) are small, non‐coding RNAs that regulate gene expression in a sequence‐specific manner. At present little is known about their role in the regulation of human UGTs. Here we sought to identify miRs that bind to the 3′UTR sequences of UGT1A (identical in all functional UGT1A isoforms), UGT2B7, and UGT2B15, representing the majority of UGTs involved in human drug glucuronidation.MethodsHEK293 cells were co‐transfected with a plasmid carrying the Firefly luciferase gene under the control of the respective UGT 3′UTR (wild‐type allele), a plasmid with Renilla luciferase (normalizer) and a miR. Using this approach we screened a commercial library containing all known human miRs.ResultsThe analysis identified multiple miRs (6 each for UGT1A and 2B7; 16 for 2B15) that down‐regulated reporter activity. Deletion of the predicted miR response element (MRE) abrogated this down‐regulation. Interestingly two miR‐21‐3p MREs in the UGT1A 3′UTR contained two different SNPs (one in each) that did not affect miR binding. Finally UGT1A and 2B15 shared common MREs for miR‐376b‐3p and miR‐103b.ConclusionsWe have identified 28 unique miRs that are likely involved in the regulation of expression of the majority of UGTs responsible for drug glucuronidation in humans. Further experiments will verify the effect of these miRs on UGT gene expression and enzyme activity in human cell lines and primary cultures.

P0312 : Preclinical evaluation of dextran-based therapeutic nanoparticles for hepatic drug delivery

P0312 : Preclinical evaluation of dextran-based therapeutic nanoparticles for hepatic drug delivery

Human hepatic stem cells transplanted into a fulminant hepatic failure Alb-TRECK/SCID mouse model exhibit liver reconstitution and drug metabolism capabilities.

IntroductionChimeric mice with humanized livers were recently established by transplanting human hepatocytes. This mouse model that is repopulated with functional human hepatocytes could be a useful tool for investigating human hepatic cell biology and drug metabolism and for other preclinical applications. Successfully transplanting human hepatocytes into mice requires that recipient mice with liver failure do not reject these human cells and provide a suitable microenvironment (supportive niche) to promote human donor cell expansion and differentiation. To overcome the limitations of current mouse models, we used Alb-TRECK/SCID mice for in vivo human immature hepatocyte differentiation and humanized liver generation.Methods1.5 μg/kg diphtheria toxin was administrated into 8-week-old Alb-TRECK/SCID mice, and the degree of liver damage was assessed by serum aspartate aminotransferase activity levels. Forty-eight hours later, mice livers were sampled for histological analyses, and the human donor cells were then transplanted into mice livers on the same day. Chimeric rate and survival rate after cell transplantation was evaluated. Expressions of human hepatic-related genes were detected. A human albumin enzyme-linked immunosorbent assay was performed after 50 days of transplantation. On day 60 after transplantation, drug metabolism was examined in mice.ResultsBoth human primary fetal liver cells and hepatic stem cells were successfully repopulated in the livers of Alb-TRECK/SCID mice that developed lethal fulminant hepatic failure after administering diphtheria toxin; the repopulation rate in some mice was nearly 100%. Compared with human primary fetal liver cells, human hepatic stem cell transplantation rescued Alb-TRECK/SCID mice with lethal fulminant hepatic failure, and human hepatic stem cell-derived humanized livers secreted more human albumin into mouse sera and also functioned as a “human liver” that could metabolize the drugs ketoprofen and debrisoquine.ConclusionOur model of a humanized liver in Alb-TRECK/SCID mice may provide for functional applications such as drug metabolism, drug to drug interactions, and promote other in vivo and in vitro studies.Electronic supplementary materialThe online version of this article (doi:10.1186/s13287-015-0038-9) contains supplementary material, which is available to authorized users.

Regulation of human hepatic drug transporter activity and expression by diesel exhaust particle extract.

Diesel exhaust particles (DEPs) are common environmental air pollutants primarily affecting the lung. DEPs or chemicals adsorbed on DEPs also exert extra-pulmonary effects, including alteration of hepatic drug detoxifying enzyme expression. The present study was designed to determine whether organic DEP extract (DEPe) may target hepatic drug transporters that contribute in a major way to drug detoxification. Using primary human hepatocytes and transporter-overexpressing cells, DEPe was first shown to strongly inhibit activities of the sinusoidal solute carrier (SLC) uptake transporters organic anion-transporting polypeptides (OATP) 1B1, 1B3 and 2B1 and of the canalicular ATP-binding cassette (ABC) efflux pump multidrug resistance-associated protein 2, with IC50 values ranging from approximately 1 to 20 μg/mL and relevant to environmental exposure situations. By contrast, 25 μg/mL DEPe failed to alter activities of the SLC transporter organic cation transporter (OCT) 1 and of the ABC efflux pumps P-glycoprotein and bile salt export pump (BSEP), whereas it only moderately inhibited those of sodium taurocholate co-transporting polypeptide and of breast cancer resistance protein (BCRP). Treatment by 25 μg/mL DEPe was next demonstrated to induce expression of BCRP at both mRNA and protein level in cultured human hepatic cells, whereas it concomitantly repressed mRNA expression of various transporters, including OATP1B3, OATP2B1, OCT1 and BSEP. Such changes in transporter expression were found to be highly correlated to those caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a reference activator of the aryl hydrocarbon receptor (AhR) pathway. This suggests that DEPe, which is enriched in known ligands of AhR like polycyclic aromatic hydrocarbons, alters drug transporter expression via activation of the AhR cascade. Taken together, these data established human hepatic transporters as targets of organic chemicals containing in DEPs, which may contribute to their systemic effects through impairing hepatic transport of endogenous compound or drug substrates of these transporters.

Serum serotonin reduced the expression of hepatic transporter Mrp2 and P-gp via regulating nuclear receptor CAR in PI-IBS rats

Hepatic transporters and drug metabolizing enzymes (DMEs) play important roles in the pharmacological effects and (or) side-effects of many drugs, and are regulated by several mediators, including neurotransmitters. This work aimed to investigate whether serum levels of 5-hydroxytryptamine (5-HT) affected the expression of hepatic transporters or DMEs. The expression of hepatic transporters was assessed using the Western-blot technique in a 2,4,6-trinitrobenzenesulfonic-acid-induced rat model of post-infectious irritable bowel syndrome (PI-IBS), in which serum levels of 5-HT were significantly elevated. To further clarify the underlying mechanism, the 5-HT precursor 5-hydroxytryptophan (5-HTP) and the 5-HT depleting agent parachlorophenylalanine (pCPA) were applied to adjust serum levels of 5-HT. Serum levels of 5-HT were measured using LC-MS/MS; the expression of hepatic transporters, DMEs, and nuclear receptors were examined by Western-blot technique. Our results showed that in PI-IBS rats the expression of multidrug resistance protein 2 (Mrp2) was significantly decreased, while colonic enterochromaffin cell density and serum levels of 5-HT were all significantly increased. Moreover, 5-HTP treatment significantly increased serum levels of 5-HT and decreased the expression of Mrp2 and glycoprotein P (P-gp), whereas treatment with pCPA markedly decreased serum levels of 5-HT and increased the expression of Mrp2 and P-gp. Our results indicated that serum 5-HT regulates the expression of Mrp2 and P-gp, and the underlying mechanism may be related to the altered expression of the nuclear receptor constitutive androstane receptor (CAR).

Intestinal and hepatic drug transporters: pharmacokinetic, pathophysiological, and pharmacogenetic roles.

The efficacy and safety of pharmacotherapies are determined by the complex processes involved in the interactions between drugs with the human body, including pharmacokinetic aspects. Among pharmacokinetic factors, it has been recognized that drug transporters play critical roles for absorption, distribution and excretion of drugs, regulating the membrane transport of drugs. The vast amounts of information on drug transporters collected in the past 20 years have been organized according to biochemical, molecular, genetic, and clinical analyses. Novel technologies, public databases, and regulatory guidelines have advanced the use of such information in drug development and clinical practice. In this review, we selected some clinically important drug transporters expressed in the intestine and liver, and introduced the research history and current knowledge of their pharmacokinetic, pathophysiological, and pharmacogenetic implications.

Evaluation of rosuvastatin as an organic anion transporting polypeptide (OATP) probe substrate: in vitro transport and in vivo disposition in cynomolgus monkeys.

Organic anion transporting polypeptides (OATPs) mediate hepatic drug uptake and serve as the loci of drug-drug interactions (DDIs). Consequently, there is a major need to develop animal models and refine in vitro-in vivo extrapolations. Therefore, the in vivo disposition of a model OATP substrate, [(3)H]rosuvastatin (RSV), was studied in the cynomolgus monkey and reported for the first time. After monkeys had received a 3-mg/kg oral dose, mass balance was achieved after bile duct cannulation (mean total recovery of radioactivity of 103.6%). Forty-two percent of the RSV dose was recovered in urine and bile, and the elimination pathways were similar to those reported for human subjects; 61.7%, 39.0%, and 2.9% of the dose was recovered in the feces, bile, and urine, respectively. The high levels of unchanged RSV recovered in urine and bile (26% of the dose) and the relatively low levels of metabolites observed indicated that RSV was eliminated largely by excretion. Also, for the first time, the in vitro inhibitory potential of cyclosporin A (CsA) toward cynomolgus monkey OATPs and sodium-taurocholate cotransporting polypeptide was studied in vitro (primary hepatocytes and transporter-transfected cells). It is concluded that one can study the CsA-RSV DDI in the cynomolgus monkey. For example, the in vitro IC50 values were within 2-fold (monkey versus human), and the increase (versus vehicle control) in the RSV AUC0-inf (6.3-fold) and Cmax (10.2-fold) with CsA (100 mg/kg) was similar to that reported for humans. The results further support the use of the cynomolgus monkey as a model to assess interactions involving OATP inhibition.

Antipsychotic Treatment in Pluripathology

Is well known some organic diseases produce psychotic symptoms. Association between HIV and presence of psychopathology is highly prevalent. For this reason, a case report of HIV, liver cirrhosis, drug abuse and psychotic disorder is presented below. The patient was a 46 year old male infected by HIV and liver cirrhosis (Child-Pugh B) secondary to HCV infection. He had had psychiatric history of major depressive disorder, cannabis use disorder, alcohol use disorder, cocaine use disorder and heroin use disorder. Without consume of heroin, cocaine and alcohol during last 5 years. He was in treatment with methadone, benzodiazepines and antiretroviral treatment. In 2013 the patient suffered a psychotic episode with an important affective and behavioral repercussion and he was admitted in an acute unit of psychiatry. It was necessary a pharmacological treatment with a limited hepatic metabolism because of his liver cirrhosis and potential drug interactions with antiretroviral treatment and methadone. So that, it was decided to use oral Paliperidone (9 mg/day), achieving a remission of psychotic symptomatology. In this case Paliperidone was safe, without side effects and good tolerance. Liver function was preserved and CD4 levels remained undetectable. In patients with severe mental illness and concomitant organic disease, complexity of treatment is a determining factor in therapeutic decisions. In conclusion, Paliperidone could be considered sure to treat psychotic symptoms in schizophrenic patients who use others medications with hepatic metabolism, drug interactions, and mild to moderate liver failure.

Preliminary observation on hepatic arterial infusion under temporary hepatic circulation occlusion in rabbits

To explore the advantages, feasibility and limitations of hepatic arterial infusion under temporary hepatic circulation occlusion. Twelve rabbits were randomly divided into two groups: hepatic artery infusion group (HAI group) and hepatic artery infusion under temporary hepatic circulation occlusion group (HAI-THCO). Microcatheters were separately inserted into the proper hepatic artery and right hepatic vein. For the HAI group, 5-Fu (10 mg/ml and 100 mg/kg) was infused into the common hepatic artery with a high pressure injector for 10 minutes. For the HAI-THCO group, the common hepatic artery and hepatic portal vein were temporarily occluded for 15 minutes using artery clamp when 5-Fu was being infused. For the two groups, at 2, 5, 10, 15, 20 and 30 min after the start of infusion, blood samples of the hepatic flow were collected from the right hepatic vein and of the systemic blood flow from the inferior vena cava, 1 ml at each time point. The blood drug concentration of these blood samples was determined by high performance liquid chromatography (HPLC). Except that at 20 and 30 min after infusion, in the HAI group, the blood drug concentration of hepatic circulation was significantly higher than that of systemic circulation (P < 0.05). But in the HAI-THCO group, the blood drug concentration of hepatic circulation was significantly higher than that of systemic circulation at all the time points (P < 0.05). The hepatic circulation blood drug level of the HAI-THCO group was always significantly higher than that of the HAI group (P < 0.05), but the systemic circulation blood drug concentration of the HAI-THCO group was always lower (P < 0.05). The hepatic circulation maximum concentration (Cmax) of blood drug concentration of the HAI-THCO and HAI groups was (23.057±3.270) µg/ml and (4.408±1.092) µg/ml, respectively, and the Cmax of HAI-THCO group was significantly higher (P < 0.001), being 5.23 times of that of HAI group. The systemic circulation Cmax of the two groups was (1.456±0.217) µg/ml and (2.335±0.669) µg/ml, respectively, and the Cmax of HAI group was 1.60 times higher than that of the HAI-THCO group (P = 0.022). The hepatic circulation AUC of HAI-THCO and HAI groups was (368.927±52.416) µg·min·ml(-1) and (65.630±14.928) µg·min·ml(-1), respectively. The AUC of HAI-THCO group was 5.62 times higher than that of the HAI group (P < 0.001). The systemic circulation AUC of the two groups was (27.193±3.948) µg·min·ml(-1) and (45.301±12.275) µg·min·ml(-1), respectively. The AUC of HAI group was 1.67 times higher than that of the HAI-THCO group (P = 0.014). HAI-THCO is a simple and effective regional hepatic infusion chemotherapy technique. It can be performed through occluding the common hepatic artery and the hepatic portal vein by balloon catheter. HAI-THCO can not only increase the blood drug concentration in the hepatic circulation, but also decrease the blood drug concentration in the systemic circulation, therefore, distinctly lowering the systemic toxicity.