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1.
Heliyon ; 10(16): e36031, 2024 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-39229547

RESUMO

Background: Gastrodin is the active monomer of the Chinese herb Rhizoma Gastrodiae with the largest quantity of active components. Gastrodin is commonly used in the treatment of central nervous system disorders such as headaches and epilepsy due to its sedating and hypnotic properties. Its pharmacological mechanism and clinical application have been extensively explored due to its low toxicity. Methods: To investigate the molecular mechanism of hepatic uptake of Gastrodin in rats, animals were randomly assigned to three groups: control group, rifampicin (RIF) group, and adrenalone (ADR) group. Blood samples were collected through the cardiac puncture 90, 180, and 300 min after injection, respectively. Rats were sacrificed 300 min after administration, and liver tissue was collected. Gastrodin concentration was determined by HPLC, and the Kp value was calculated. Results: After administering the inhibitors of organic cation transporters (OCTs) and organic anion transporting polypeptides (OATPs), the KP values in the experimental groups were significantly lower compared to the blank control group (P < 0.05). Conclusions: These findings imply that Gastrodin may be a substrate for both OCTs and OATPs.

2.
Drug Metab Dispos ; 2024 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-39103225

RESUMO

The influence of transporters on the pharmacokinetics of drugs is being increasingly recognized, and drug-drug interactions (DDIs) via modulation of transporters could lead to clinical adverse events. Organic anion-transporting polypeptide 1B (OATP1B) are liver specific uptake transporters in humans that can transport a broad range of substrates, including statins. It is a challenge to predict OATP1B-mediated DDIs using preclinical animal models because of species differences in substrate specificity and abundance levels of transporters. PXB-mice are chimeric mice with humanized livers that are highly repopulated with human hepatocytes and have been widely used for drug metabolism and pharmacokinetics studies in drug discovery. In the present study, we measured the exposure increases (blood AUC and Cmax) of ten OATP1B substrates in PXB-mice upon co-administration with rifampin, a potent OATP1B specific inhibitor. These data in PXB-mice were then compared with the observed DDIs between OATP1B substrates and single-dose rifampin in humans. Our findings suggest that the DDIs between OATP1B substrates and rifampin in PXB-mouse are comparable with the observed DDIs in the clinic. Since most OATP1B substrates are metabolized by CYPs and/or are substrates of P-glycoprotein (P-gp), we further validated the utility of PXB-mice to predict complex DDIs involving inhibition of OATP1B, CYPs and P-gp using CsA and gemfibrozil as perpetrators. Overall, the data support that the chimeric mice with humanized livers could be a useful tool for the prediction of hepatic OATP1B-mediated DDIs in humans. Significance Statement The ability of PXB-mouse with humanized liver to predict OATP1B-mediated drug-drug interactions (DDIs) in humans was evaluated. The plasma exposure increases of ten OATP1B substrates with rifampin, an OATP1B inhibitor, in PXB-mice have a good correlation with those observed in humans. More importantly, PXB-mice can predict complex DDIs including inhibition of OATP1B, CYPs and P-gp in humans. PXB-mice are a promising useful tool to assess OATP1B-mediated clinical DDIs.

3.
Xenobiotica ; 52(7): 729-741, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36371761

RESUMO

1. TP0463518, a novel hypoxia-inducible factor prolyl hydroxylase inhibitor, is reportedly excreted predominantly through urinary excretion in an unchanged form in humans, with partial biliary excretion also possible. However, the clearance mechanisms remain unclear. The aim of this study was to investigate the clearance mechanisms in humans and to assess species differences in the excretion routes.2. TP0463518 was not metabolised in rat, dog, or human hepatocytes. TP0463518 is a substrate for human BCRP, OATP1B1, OATP1B3, and OAT3, suggesting that renal uptake by OAT3 is probably the predominant clearance route, with hepatic uptake by OATP1B1 and OATP1B3 contributing partially to clearance in humans.3. A species difference in excretion routes was observed. The unchanged urinary excretion rates in humans, male rats, female rats, dogs, and monkeys were 80.7%, 0.1%, 40.9%, 15.2%, and 72.6%, respectively. Urinary excretion was predominant in humans and monkeys, while only biliary excretion was observed in male rats. Uptake studies using hepatocytes showed that the hepatic uptake clearance in rats was 13.6-fold higher than that in humans. Therefore, not only reabsorption via renal tubules, but also hepatic uptake seems to be involved in the species differences in excretion routes between rats and humans.


Assuntos
Prolil Hidroxilases , Inibidores de Prolil-Hidrolase , Humanos , Feminino , Masculino , Ratos , Animais , Cães , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Proteínas de Neoplasias , Hipóxia
4.
J Pak Med Assoc ; 72(4): 782-783, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35614625

RESUMO

Tc-99m methylene diphosphonate (MDP) bone scan is an effective tool for the evaluation of benign and malignant skeletal disorders. Hepatic uptake on bone scan is an unexpected finding and whenever present, the cause must be determined as the distinction between technical and pathological causes is important to direct further patient management. Identification of these abnormalities will decrease errors and provide cardinal clinical information. We present the image of a patient with Osteosarcoma of the left femur; who underwent bone scan for metastatic workup which showed diffuse hepatic uptake.


Assuntos
Neoplasias Ósseas , Osteossarcoma , Neoplasias Ósseas/diagnóstico por imagem , Humanos , Osteossarcoma/diagnóstico por imagem , Osteossarcoma/patologia , Compostos Radiofarmacêuticos , Medronato de Tecnécio Tc 99m , Doente Terminal
5.
Drug Metab Pharmacokinet ; 44: 100449, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35395593

RESUMO

It is widely accepted that uptake and efflux transporters on clearance organs play crucial roles in drug disposition. Although in vitro transporter assay system can identify the intrinsic properties of the target transporters, it is not so easy to precisely predict in vivo pharmacokinetic parameters from in vitro data. Positron emission tomography (PET) imaging is a useful tool to directly assess the activity of drug transporters in humans. We recently developed a practical synthetic method for fluorine-18-labeled pitavastatin ([18F]PTV) as a PET probe for quantitative evaluation of hepatobiliary transport. In the present study, we conducted clinical PET imaging with [18F]PTV and compared the pharmacokinetic properties of the probe for healthy subjects with or without rifampicin pretreatment. Rifampicin pretreatment significantly suppressed the hepatic maximum concentration and biliary excretion of the probe to 52% and 34% of the control values, respectively. Rifampicin treatment markedly decreased hepatic uptake clearance (21% of the control), and moderately canalicular efflux clearance with regard to hepatic concentration (52% of the control). These results demonstrate that [18F]PTV is a useful probe for clinical investigation of the activities of hepatobiliary uptake/efflux transporters in humans.


Assuntos
Quinolinas , Rifampina , Transporte Biológico , Humanos , Fígado/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Quinolinas/metabolismo , Quinolinas/farmacologia , Rifampina/metabolismo , Rifampina/farmacologia
6.
Pharm Biol ; 60(1): 359-373, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35171063

RESUMO

CONTEXT: Patients with non-alcoholic steatohepatitis (NASH) may have a simultaneous intake of pravastatin and evodiamine-containing herbs. OBJECTIVE: The effect of evodiamine on the pharmacokinetics of pravastatin and its potential mechanisms were investigated in NASH rats. MATERIALS AND METHODS: The NASH model was conducted with feeding a methionine choline-deficient (MCD) diet for 8 weeks. Sprague-Dawley rats were randomised equally (n = 6) into NASH group, evodiamine group (10 mg/kg), pravastatin group (10 mg/kg), and evodiamine (10 mg/kg) + pravastatin (10 mg/kg) group. Normal control rats were fed a standard diet. Effects of evodiamine on the pharmacokinetics, distribution, and uptake of pravastatin were investigated. RESULTS: Evodiamine decreased Cmax (159.43 ± 26.63 vs. 125.61 ± 22.17 µg/L), AUC0-t (18.17 ± 2.52 vs. 14.91 ± 2.03 mg/min/L) and AUC0-∞ (22.99 ± 2.62 vs. 19.50 ± 2.31 mg/min/L) of orally administered pravastatin in NASH rats, but had no significant effect in normal rats. Evodiamine enhanced the uptake (from 154.85 ± 23.17 to 198.48 ± 26.31 pmol/mg protein) and distribution (from 736.61 ± 108.07 to 911.89 ± 124.64 ng/g tissue) of pravastatin in NASH rat liver. The expression of Oatp1a1, Oatp1a4, and Oatp1b2 was up-regulated 1.48-, 1.38-, and 1.51-fold by evodiamine. Evodiamine decreased the levels of IL-1ß, IL-6, and TNF-α by 27.82%, 24.76%, and 29.72% in NASH rats, respectively. DISCUSSION AND CONCLUSIONS: Evodiamine decreased the systemic exposure of pravastatin by up-regulating the expression of OATPs. These results provide a reference for further validation of this interaction in humans.


Assuntos
Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Transportadores de Ânions Orgânicos/genética , Pravastatina/farmacocinética , Quinazolinas/farmacologia , Animais , Área Sob a Curva , Interações Ervas-Drogas , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacocinética , Masculino , Ratos , Ratos Sprague-Dawley , Regulação para Cima/efeitos dos fármacos
7.
Mol Nutr Food Res ; 66(2): e2100800, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34826203

RESUMO

SCOPE: 1,2-unsaturated pyrrolizidine alkaloids (PAs) are secondary plant metabolites that are found in many plant species throughout the world. They are of concern for risk assessment as consumption of contaminated foodstuff can cause severe liver damage. Of late, transporter-mediated uptake and transport has advanced as a vital determinant of PA toxicity. In this study, the authors investigate a transporter-mediated uptake of PAs and its implications in PA toxicity. METHODS AND RESULTS: We show that transporter expression levels are significantly affected by treatment with the PAs senecionine (Sc) and retrorsine (Re) in the human hepatoma cell line HepaRG. Furthermore, the specific contribution to PA uptake of the two transporters Na+ /taurocholate co-transporting polypeptide (SLC10A1) and organic cation transporter I (SLC22A1), both belonging to the heterogeneous solute carrier super family, is investigated by means of a siRNA-mediated knockdown approach. Knockdown of both uptake transporters result in reduced uptake of Re and Sc in a time-dependent manner and attenuated PA-mediated cytotoxic effects in HepaRG cells. CONCLUSION: Our results confirm previous findings of active transport mechanisms of PAs into hepatocytes and highlight the importance of toxicokinetic studies for the risk assessment of PAs.


Assuntos
Doença Hepática Induzida por Substâncias e Drogas , Alcaloides de Pirrolizidina , Cátions/metabolismo , Doença Hepática Induzida por Substâncias e Drogas/etiologia , Doença Hepática Induzida por Substâncias e Drogas/metabolismo , Hepatócitos , Humanos , Peptídeos/metabolismo , Alcaloides de Pirrolizidina/toxicidade , Ácido Taurocólico/metabolismo
8.
Artigo em Inglês | MEDLINE | ID: mdl-34637925

RESUMO

The ability to accept cholesterol from cells and to promote reverse cholesterol transport (RCT) represents the best characterized antiatherogenic function of HDL. Studies carried out in animal models have unraveled the multiple mechanisms by which these lipoproteins drive cholesterol efflux from macrophages and cholesterol uptake to the liver. Moreover, the influence of HDL composition and the role of lipid transporters have been clarified by using suitable transgenic models or through experimental design employing pharmacological or nutritional interventions. Cholesterol efflux capacity (CEC), an in vitro assay developed to offer a measure of the first step of RCT, has been shown to associate with cardiovascular risk in several human cohorts, supporting the atheroprotective role of RCT in humans as well. However, negative data in other cohorts have raised concerns on the validity of this biomarker. In this review we will present the most relevant data documenting the role of HDL in RCT, as assessed in classical or innovative methodological approaches.


Assuntos
HDL-Colesterol/metabolismo , Colesterol/metabolismo , Lipoproteínas HDL/metabolismo , Fígado/metabolismo , Animais , Transporte Biológico/genética , HDL-Colesterol/genética , Humanos , Lipoproteínas HDL/genética
9.
Pharmacol Ther ; 229: 107938, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34171335

RESUMO

The accuracy in predicting in vivo hepatic clearance of drugs from in vitro data (often termed as in vitro-to-in vivo extrapolation, IVIVE) has improved in part by applying the extended-clearance concept that considers the interplay between hepatic metabolism and uptake/efflux processes. However, the IVIVE-based prediction performs poorly in predicting the hepatic uptake clearance of highly albumin-bound anionic drugs. Their hepatic uptake clearances tend to be much higher than expected based on the free-drug theory. Such observation can be attributable to a phenomenon called albumin-mediated hepatic uptake, for which various models have been thus far proposed. Our group has been applying a facilitated-dissociation model, which assumes the enhanced dissociation of the drug-albumin complex upon interaction with the cell surface. By considering the albumin-mediated hepatic uptake (using the facilitated-dissociation model or alternative kinetic models), a number of investigations demonstrated the improvement in the prediction accuracy for the hepatic clearance of highly protein-bound anionic drugs that are substrates for hepatic uptake transporters. This review summarizes the reported kinetic analyses of the albumin-mediated hepatic uptake of highly albumin-bound drugs concerning the IVIVE and the clinical and physiological relevance.


Assuntos
Hepatócitos , Transportadores de Ânions Orgânicos , Albuminas/metabolismo , Hepatócitos/metabolismo , Humanos , Fígado/metabolismo , Taxa de Depuração Metabólica , Modelos Biológicos , Transportadores de Ânions Orgânicos/metabolismo , Preparações Farmacêuticas/metabolismo
10.
Pharmacol Res Perspect ; 9(5): e00877, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34619012

RESUMO

Epyrifenacil is a novel herbicide that acts as an inhibitor of protoporphyrinogen oxidase (PPO) and produces hepatotoxicity in rodents by inhibiting PPO. Our previous research revealed that the causal substance of hepatotoxicity is S-3100-CA, a major metabolite of epyrifenacil, and that human hepatocyte uptake of S-3100-CA was significantly lower than rodent one, suggesting less relevant to hepatotoxicity in humans. To clarify the species difference in the uptake of S-3100-CA, we focused on organic anion transporting polypeptides (OATPs) and carried out an uptake assay using human, rat, and mouse OATP hepatic isoforms-expressing 293FT cells. As a result, all the examined OATPs were found to contribute to the S-3100-CA uptake, suggesting that the species difference was not due to the differences in selectivity toward OATP isoforms. When [14 C]epyrifenacil was administered to mice, the liver concentration of S-3100-CA was higher in males than in females. Furthermore, when [14 C]epyrifenacil was administered with OATP inhibitors, the liver/plasma ratio of S-3100-CA was significantly decreased by rifampicin, an Oatp1a1/Oatp1a4 inhibitor in mice, but not by digoxin, an Oatp1a4-specific inhibitor. This result indicates that Oatp1a1, the predominant transporter in male mice, is the main contributor to the hepatic transport of S-3100-CA, and consequently to the gender difference. Moreover, we conclude that the species difference in the hepatic uptake of S-3100-CA observed in our previous research is not due to differences in the selectivity toward OATP isoforms but rather to the significantly higher expression of OATPs which mediate uptake of S-3100-CA in rodents than in humans.


Assuntos
Herbicidas , Fígado , Proteínas de Transporte de Cátions Orgânicos , Pirimidinas , Animais , Feminino , Humanos , Masculino , Camundongos , Ratos , Ácidos Carboxílicos/metabolismo , Digoxina/farmacologia , Herbicidas/metabolismo , Fígado/metabolismo , Transportadores de Ânions Orgânicos/antagonistas & inibidores , Transportadores de Ânions Orgânicos/metabolismo , Transportadores de Ânions Orgânicos Sódio-Independentes , Proteínas de Transporte de Cátions Orgânicos/antagonistas & inibidores , Proteínas de Transporte de Cátions Orgânicos/metabolismo , Protoporfirinogênio Oxidase/antagonistas & inibidores , Piridinas/metabolismo , Pirimidinas/metabolismo , Rifampina/farmacologia
11.
Pharmaceutics ; 13(7)2021 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-34371764

RESUMO

The accumulation of high levels of 99mTc-tetrofosmin (99mTc-TF) in the hepatobiliary system can lead to imaging artifacts and interference with diagnosis. The present study investigated the transport mechanisms of 99mTc-TF and attempted to apply competitive inhibition using a specific inhibitor to reduce 99mTc-TF hepatic accumulation. In this in vitro study, 99mTc-TF was incubated in HEK293 cells expressing human organic anion transporting polypeptide 1B1 (OATP1B1), OATP1B3, OATP2B1, organic anion transporter 2 (OAT2), organic cation transporter 1 (OCT1), OCT2, and Na+-taurocholate cotransporting polypeptide with or without each specific inhibitor to evaluate the contribution of each transporter to 99mTc-TF transportation. In vivo studies, dynamic planar imaging, and single photon emission computed tomography (SPECT) experiments with rats were performed to observe alterations to 99mTc-TF pharmacokinetics using cimetidine (CMT) as an OCT1 inhibitor. Time-activity curves in the liver and heart were acquired from dynamic data, and the 99mTc-TF uptake ratio was calculated from SPECT. From the in vitro study, 99mTc-TF was found to be transported by OCT1 and OCT2. When CMT-preloaded rats and control rats were compared, the hepatic accumulation of the 99mTc-TF was reduced, and the time to peak heart count shifted to an earlier stage. The hepatic accumulation of 99mTc-TF was markedly suppressed, and the heart-to-liver ratio increased 1.6-fold. The pharmacokinetics of 99mTc-TF were greatly changed by OCT1 inhibitor. Even in humans, the administration of OCT1 inhibitor before cardiac SPECT examination may reduce 99mTc-TF hepatic accumulation and contribute to the suppression of artifacts and the improvement of SPECT image quality.

13.
J Pharm Sci ; 110(1): 376-387, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33122051

RESUMO

Hepatic uptake clearance has been measured in suspended human hepatocytes (SHH). Plated human hepatocytes (PHH) after short-term culturing are increasingly employed to study hepatic transport driven mainly by its higher throughput. To know pros/cons of both systems, the hepatic uptake clearances of several organic anion transporting polypeptide 1B substrates were compared between PHH and SHH by determining the initial uptake velocities or through dynamic model-based analyses. For cerivastatin, pitavastatin and rosuvastatin, initial uptake clearances (PSinf) obtained using PHH were comparable to those using SHH, while cell-to-medium concentration (C/M) ratios were 2.7- to 5.4-fold higher. For pravastatin and dehydropravastatin, hydrophilic compounds with low uptake/cellular binding, their PSinf and C/M ratio in PHH were 1.8- to 3.2-fold lower than those in SHH. These hydrophilic substrates are more prone to wash-off during the uptake study using PHH, which may explain the apparently lower uptake than SHH. The C/M ratios obtained using PHH were stable over an extended time, making PHH suitable to estimate the C/M ratios and hepatocyte-to-medium unbound concentration ratios (Kp,uu). In conclusion, PHH is useful in evaluating hepatic uptake/efflux clearances and Kp,uu of OATP1B substrates in a high-throughput manner, however, a caution is warranted for hydrophilic drugs with low uptake/cellular binding.


Assuntos
Hepatócitos , Transportadores de Ânions Orgânicos , Transporte Biológico , Hepatócitos/metabolismo , Humanos , Fígado/metabolismo , Transportadores de Ânions Orgânicos/metabolismo , Pravastatina/metabolismo
14.
AAPS J ; 23(1): 1, 2020 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-33196949

RESUMO

This study focused on exploring various in vitro to in vivo extrapolation (IVIVE) approaches with the primary goal of improving human hepatic clearance (CL) prediction for OATP substrates. To that effect, the impact of albumin-mediated uptake in human hepatocytes was investigated. In vitro hepatic uptake assay using suspended human hepatocytes was performed with 16 selected OATP substrates to determine the uptake CL in the absence and presence of 4% BSA and unbound hepatocyte to media partition coefficient (Kpuu). Substantial enhancement of the unbound uptake CL (PSu,inf) was observed in the presence of 4% BSA, demonstrating "albumin-mediated" uptake. Prediction of human hepatic CL was performed using two non-traditional IVIVE approaches: initial uptake CL (PSu,inf) and intrinsic metabolic CL (CLint,met) corrected by Kpuu based on extended clearance concept. Compared to traditional IVIVE using CLint,met only, the two tested IVIVE approaches significantly improved the prediction of human hepatic CL. Particularly, direct extrapolation from PSu,inf (+BSA) showed the most robust correlation with in vivo human hepatic CL for all 16 compounds with bias of 1.9-2.0 for two lots of human hepatocytes, respectively. In addition, PSu,inf (+BSA) and Kpuu were also determined in suspended cynomolgus monkey hepatocytes. Prediction of monkey hepatic CL was improved by both approaches, although with more bias compared to human. These results suggested supplementing 4% BSA in human hepatocyte uptake assay provides a useful tool to characterize hepatic uptake CL for OATP substrates, enabling more accurate human CL prediction without any empirical scaling factor (ESF).


Assuntos
Meios de Cultura/metabolismo , Eliminação Hepatobiliar , Fígado/metabolismo , Cultura Primária de Células/métodos , Soroalbumina Bovina/metabolismo , Animais , Cães , Hepatócitos/metabolismo , Humanos , Macaca fascicularis , Células Madin Darby de Rim Canino , Modelos Biológicos , Transportadores de Ânions Orgânicos , Permeabilidade , Ratos , Especificidade da Espécie
15.
Indian J Nucl Med ; 35(3): 238-240, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33082683

RESUMO

Tc-99m-methylene diphosphonate (MDP) bone scintigraphy is mainly directed toward identifying sites of altered skeletal metabolism and abnormal foci of calcium phosphate deposition due to various etiologies. One of the requirements of an ideal bone scintigraphy is little or no extraosseous uptake. Nonosseous uptake of MDP in the bone scintigraphy is an unusual finding. We report a case of carcinoma prostate referred for bone scan, where diffuse hepatic and splenic uptake has been seen on the bone scan. However, on a further repeat bone scan, there was no nonosseous uptake.

16.
J Pharm Sci ; 109(10): 3190-3205, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32649937

RESUMO

The main objective was to investigate the effect of albumin (ALB) and/or alpha-1-acid glycoprotein (AGP) on the hepatic clearance (CLh) of the drugs that bind, extensively, to both proteins. Isolated perfused livers from male Sprague Dawley rats (IPRL) were performed for perampanel (PER) and fluoxetine (FLU), using physiological solutions in four scenarios (n = 3 rats/scenario/drug): 1) without plasma proteins (WO), 2) with bovine ALB (40 g/L), 3) with bovine AGP (1 g/L), and 4) with mixture of both proteins (MIX). PER is poorly to moderately metabolized (hepatic extraction = 0.2-0.7), while FLU is highly metabolized (hepatic extraction = 0.8-0.99). The metabolic kinetics were fitted to the Michaelis-Menten model. For the PER, the parameters were Vmax = 90, 16.4, 86.1 and 16.9 (nmol/min/g liver) and unbound Km = 17, 1.7, 38.3 and 1.4 (µM) for the scenarios WO, with ALB, with AGP and with MIX, respectively. As for FLU, the parameters were Vmax = 65.5, 18.5, 33.8 and 12.2 (nmol/min/g liver) and unbound Km = 1.5, 0.03, 0.14 and 0.0466.31 (µM) in all four scenarios, respectively. In conclusion, a protein-mediated hepatic uptake likely occurred only at low concentrations for both drugs (i.e., therapeutic concentrations) in the presence of plasma proteins (except for the scenario of PER with AGP).


Assuntos
Fluoxetina , Preparações Farmacêuticas , Animais , Bovinos , Fluoxetina/metabolismo , Cinética , Fígado/metabolismo , Masculino , Taxa de Depuração Metabólica , Nitrilas , Perfusão , Preparações Farmacêuticas/metabolismo , Ligação Proteica , Piridonas , Ratos , Ratos Sprague-Dawley
17.
J Control Release ; 322: 217-226, 2020 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-32145269

RESUMO

Lipid nanoparticles (LNPs) are one of the more promising technologies for efficiently delivering nucleic acids in vivo. Hepatocytes are the primary target cells of LNPs that are delivered via the apolipoprotein E (ApoE)-low density lipoprotein receptor (LDLR) pathway, an endogenous targeting pathway. This robust targeting mechanism results in the specific and efficient delivery of nucleic acids to hepatocytes. Trivalent N-acetyl-D-galactosamine (GalNAc) is known to be a high-affinity exogenous ligand against the asialoglycoprotein receptor (ASGPR), which is highly expressed on hepatocytes. In this study, we report that the kinetics of the hepatic uptake process between the two types of targeting pathways are different. Rapid blood clearance, accumulation to the space of Disse and a subsequent slow cellular uptake was observed in the case of the endogenous ApoE-LDLR pathway. On the other hand, both blood clearance and cellular uptake were more gradual in the case of the exogenous GalNAc-ASGPR pathway. Interactions between ApoE-bound LNPs and hepatic heparan sulfate proteoglycans (HSPGs) were involved in the rapid blood clearance and accumulation to the space of Disse in the case of the endogenous pathway. The findings presented here contribute to a more precise understanding of the mechanism of hepatic uptake and to the rational design of hepatocyte-targeting nanoparticles.


Assuntos
Galactosamina , Nanopartículas , Acetilgalactosamina , Apolipoproteínas E , Receptor de Asialoglicoproteína/metabolismo , Hepatócitos/metabolismo , Cinética , Lipídeos , Receptores de LDL
18.
Biochem Pharmacol ; 174: 113829, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32001236

RESUMO

Nicotinic acid (NA) and nicotinamide (NAM) are biosynthetic precursors of nicotinamide adenine dinucleotide (NAD+) - a physiologically important coenzyme that maintains the redox state of cells. Mechanisms driving their entry into cells are not well understood. Here we evaluated the hepatic uptake mechanism(s) of NA and NAM using transporter-transfected cell systems and primary human hepatocytes. NA showed robust organic anion transporter (OAT)2-mediated transport with an uptake ratio (i.e., ratio of accumulation in transfect cells to wild-type cells) of 9.7 ± 0.3, and a Michaelis-Menten constant (Km) of 13.5 ± 3.3 µM. However, no transport was apparent via other major hepatic uptake and renal secretory transporters, including OAT1/3/4, organic anion transporting polypeptide (OATP)1B1/1B3/2B1, sodium-taurocholate co-transporting polypeptide, organ cation transporter 1/2/3. OAT2-specific transport of NA was inhibited by ketoprofen and indomethacin (known OAT2 inhibitors) in a concentration-dependent manner. Similarly, NA uptake into primary human hepatocytes showed pH- and concentration-dependence and was subject to inhibition by specific OAT2 inhibitors. Unlike NA, NAM was not transported by the hepatic and renal solute carriers upon assessment in transfected cells, although its uptake into human hepatocytes was significantly inhibited by excess unlabelled NAM and a pan-SLC inhibitor (rifamycin SV 1 mM). In conclusion, these studies demonstrate, for the first time, a specific transport mechanism for NA uptake in the human liver and suggest that OAT2 (SLC22A7) has a critical role in its physiological and pharmacological functions.


Assuntos
Hepatócitos/metabolismo , Fígado/metabolismo , Niacina/metabolismo , Transportadores de Ânions Orgânicos Sódio-Independentes/metabolismo , Transporte Biológico/efeitos dos fármacos , Transporte Biológico/fisiologia , Células Cultivadas , Relação Dose-Resposta a Droga , Células HEK293 , Hepatócitos/efeitos dos fármacos , Humanos , Fígado/citologia , Fígado/efeitos dos fármacos , Rifamicinas/farmacologia
19.
J Nucl Med Technol ; 48(1): 85-86, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31182667

RESUMO

We report a rare case of incidental diffuse hot liver on 99mTc-macroaggregated albumin lung perfusion scanning done to exclude pulmonary embolism. This scintigraphic finding suggested synchronous obstruction of the superior and inferior venae cavae, later confirmed on CT angiography. Although many cases of focal hepatic uptake have been reported, reports of diffuse uptake because of vena cava obstruction are scarce in the literature.


Assuntos
Fígado/metabolismo , Embolia Pulmonar/diagnóstico por imagem , Cintilografia/métodos , Agregado de Albumina Marcado com Tecnécio Tc 99m/química , Veia Cava Inferior/diagnóstico por imagem , Angiografia por Tomografia Computadorizada , Difusão , Feminino , Humanos , Pulmão , Especificidade de Órgãos , Imagem de Perfusão , Adulto Jovem
20.
Xenobiotica ; 50(4): 479-487, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31368836

RESUMO

Jatrorrhizine possesses a wide spectrum of pharmacological activities. However, the mechanism underlying hepatic uptake of jatrorrhizine remains unclear.Rat liver slices, isolated rat hepatocytes and human embryonic kidney 293 (HEK293) cells stably expressing human organic anion-transporting polypeptide (OATP) and organic cation transporter (OCT) were used to evaluate the hepatic uptake of jatrorrhizine in this study.Uptake of jatrorrhizine in rat liver slices and isolated rat hepatocytes was significantly inhibited by glycyrrhizic acid (Oatp1b2 inhibitor) and prazosin (Oct1 inhibitor), but not by ibuprofen (Oatp1a1 inhibitor) or digoxin (Oatp1a4 inhibitor). Uptake of jatrorrhizine in OATP1B3 and OCT1-HEK293 cells indicated a saturable process with the Km of 8.20 ± 1.28 and 4.94 ± 0.55 µM, respectively. However, the transcellular transport of jatrorrhizine in OATP1B1-HEK293 cells was not observed. Rifampicin (OATP inhibitor) for OATP1B3-HEK293 cells and prazosin for OCT1-HEK293 cells could inhibit the uptake of jatrorrhizine with the IC50 of 5.49 ± 1.05 and 2.77 ± 0.72 µM, respectively.The above data indicate that hepatic uptake of jatrorrhizine is involved in both OATP and OCT, which may have important roles in jatrorrhizine liver disposition and potential drug-drug interactions.


Assuntos
Berberina/análogos & derivados , Transportadores de Ânions Orgânicos/metabolismo , Animais , Berberina/metabolismo , Transporte Biológico , Cátions , Células HEK293 , Humanos , Fígado/metabolismo , Transportador 1 de Ânion Orgânico Específico do Fígado , Ratos
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