CYP3A4 Activity Research Articles

Evaluation of In Vitro Metabolism- and Transporter-Based Drug Interactions with Sunscreen Active Ingredients.

The aim of this study was to examine the ability of sunscreen active ingredients to inhibit in vitro drug metabolism via cytochrome P450 (CYP) enzymes and drug uptake transporters. Metabolism assays with human liver microsomes were conducted for CYP2C9, CYP2D6 and CYP3A4 using probe substrates warfarin, bufuralol and midazolam, respectively. Uptake transporter assays with transfected cell lines were conducted for OAT3, OCT2 and OATP1B1 with probe substrates estrone-3-sulfate, metformin and rosuvastatin, respectively. Six sunscreen active ingredients, avobenzone, enzacamene, oxybenzone, octinoxate, trolamine, and homosalate, were evaluated up to their aqueous solubility limits in the assays. None of the sunscreen active ingredients inhibited CYP2D6 or CYP3A4 activities in the microsomes at concentration ranges up to tenfold higher than their known clinical total plasma levels. Only enzacamene, oxybenzone and trolamine were found to be inhibitory to CYP2C9 activity with IC50 values of 14.76, 22.46 and 154.7µM, respectively. Avobenzone, enzacamene, homosalate and octinoxate were not inhibitory to the uptake transporters at the evaluated concentrations. Oxybenzone was inhibitory to OAT3 and OCT2 with IC50 values of 39.93 and 42.77µM, respectively. Trolamine also inhibited uptake in OAT3 and OCT2 transfected cells with IC50 values of 448.1 and 1376μM, respectively. Although enzacamene, oxybenzone and trolamine inhibited CYP2C9 and the renal transporters OAT3 and OCT2 in vitro, their IC50 values exceeded total plasma levels found in clinical studies. Therefore, it is unlikely that these sunscreen active ingredients in sunscreen products will inhibit the metabolism or transport of co-administered drugs in consumers.

PK/PD investigation of antiviral host matriptase/TMPRSS2 inhibitors in cell models

Certain corona- and influenza viruses utilize type II transmembrane serine proteases for cell entry, making these enzymes potential drug targets for the treatment of viral respiratory infections. In this study, the cytotoxicity and inhibitory effects of seven matriptase/TMPRSS2 inhibitors (MI-21, MI-463, MI-472, MI-485, MI-1900, MI-1903, and MI-1904) on cytochrome P450 enzymes were evaluated using fluorometric assays. Additionally, their antiviral activity against influenza A virus subtypes H1N1 and H9N2 was assessed. The metabolic depletion rates of these inhibitors in human primary hepatocytes were determined over a 120-min period by LC–MS/MS, and PK parameters were calculated. The tested compounds, with the exception of MI-21, displayed potent inhibition of CYP3A4, while all compounds lacked inhibitory effects on CYP1A2, CYP2C9, CYP2C19, and CYP2D6. The differences between the CYP3A4 activity within the series were rationalized by ligand docking. Elucidation of PK parameters showed that inhibitors MI-463, MI-472, MI-485, MI-1900 and MI-1904 were more stable compounds than MI-21 and MI-1903. Anti-H1N1 properties of inhibitors MI-463 and MI-1900 and anti-H9N2 effects of MI-463 were shown at 20 and 50 µM after 24 h incubation with the inhibitors, suggesting that these inhibitors can be applied to block entry of these viruses by suppressing host matriptase/TMPRSS2-mediated cleavage.

1β-Hydroxydeoxycholic Acid as an Endogenous Biomarker in Human Plasma for Assessment of CYP3A Clinical Drug-Drug Interaction Potential.

4β-Hydroxycholesterol (4β-HC) in plasma has been used as a biomarker to assess CYP3A drug-drug interaction (DDI) potential during drug development. However, due to the long half-life and narrow dynamic range of 4β-HC, its use has been limited to the identification of CYP3A inducers, but not CYP3A inhibitors. The formation of 1β-hydroxydeoxycholic acid (1β-OH DCA) from deoxycholic acid (DCA) is mediated by CYP3A, thus 1β-OH DCA can potentially serve as an alternative to 4β-HC for assessment of CYP3A DDI potential. To study this feasibility, we developed a sensitive liquid chromatography-tandem mass spectrometry method for the simultaneous quantitation of 1β-OH DCA and its glycine and taurine conjugates in human plasma with the lower limit of quantitation of 50 pg/ml, which enabled the quantitation of basal levels and further reduction. The method was applied to a DDI study to assess how 1β-OH DCA and its glycine and taurine conjugates would respond to CYP3A induction or inhibition. Rifampin induction resulted in an increase of 1β-OH DCA and its conjugates in plasma, with 6.8-, 7.8-, 8.3-, and 10.3-fold increases of area under the curve from the time of dosing to the last measurable concentration (AUCLST), area under the curve from the time of dosing to 24 hours (AUC24h), C max, and mean concentrations for total 1β-OH DCA (total of all three forms), respectively. Importantly, inhibition with itraconazole resulted in notable reduction of these biomarkers, with 84%, 85%, 82%, and 81% reductions of AUCLST, AUC24h, C max, and mean concentrations for total 1β-OH DCA, respectively. These preliminary data demonstrate for the first time that total 1β-OH DCA in plasma has the potential to serve as a biomarker for CYP3A DDI assessment in early clinical development and may provide key advantages over 4β-HC. SIGNIFICANCE STATEMENT: The authors have reported the use of total 1β-hydroxydeoxycholic acid (1β-OH DCA) (sum of 1β-OH DCA and its glycine and taurine conjugates) plasma exposure as a biomarker for CYP3A activity. Itraconazole inhibition led to an 81%-85% decrease of total 1β-OH DCA plasma exposures, whereas rifampin induction led to a 6.8- to 10.3-fold increase of total 1β-OH DCA plasma exposures. Using 1β-OH DCA exposures in plasma also provides the benefit of allowing pharmacokinetic and biomarker assessment using the same matrix.

Biochemical Characteristics of Pharmacologically Induced Hind Limb Paralysis in CD-1 Mice

A model of pharmacological paralysis in the hind limbs of CD-1 mice was introduced. In the initial phase (before paralysis), the activity of MAO-A, a key enzyme of neuroamine metabolism, was inhibited, leading to increased levels of steroid hormones and prolactin, as well as to a decrease in hepatic CYP3A4 and CYP2D6 activities and astrocytic S-100 protein secretion into the blood serum. In the second phase (paralysis manifestation), the mice exhibited hind limb paralysis development, accumulation of cortisol granules, destruction of capillaries, and aggregation of deformed red blood cells in the cerebral cortex and hippocampal regions.

Pharmacokinetic drug-drug interactions of JBPOS0101 mediated by cytochrome P450 3A4 and UDP-glucuronosyltransferases.

JBPOS0101 is a new antiepileptic drug and is a substrate of UDP-glucuronosyltransferases (UGTs) in invitro test. Invitro experiments showed different results regarding whether JBPOS0101 induces (EC50 136 μM) or inhibits (IC50 95.4-386.5 μM) cytochrome P450 (CYP) 3A4. As co-medication of JBPOS0101 and carbamazepine (CBZ) is expected in clinical settings, drug-drug interactions (DDIs) between them should be determined. This study aimed to investigate pharmacokinetic (PK) interactions of JBPOS0101 influenced by CYP3A4 and UGTs using midazolam (MDZ) and CBZ. A two-cohort, open-label, fixed-sequence study was conducted in healthy Koreans. In cohort A, subjects received MDZ IV alone, and then JBPOS0101 were co-administered with MDZ after oral doses of JBPOS0101 for 7 days. In cohort B, multiple doses of JBPOS0101 and CBZ were administered respectively, and subjects received both together for 7 days. Serial blood samples were collected for PK analysis. When MDZ and JBPOS0101 were co-administered, the systemic exposure of MDZ decreased by 30%. Meanwhile, JBPOS0101 did not significantly changed the PK of CBZ. CBZ decreased the systemic exposure of JBPOS0101 at steady state by 40%, respectively. With IV administration of MDZ, JBPOS0101 acted as a weak inducer of hepatic CYP3A4 and decreased systemic exposure of MDZ. The ability of JBPOS0101 to similarly modulate gut CYP3A4 activity will require further evaluation. Co-administration of multiple doses of JBPOS0101 and CBZ did not significantly alter CBZ pharmacokinetics, but the clinical impact of decreased systemic exposure of JBPOS0101 by CBZ should be further considered.

Impact of obesity and roux-en-Y gastric bypass on the pharmacokinetics of (R)- and (S)-omeprazole and intragastric pH.

This study employed physiologically-based pharmacokinetic-pharmacodynamics (PBPK/PD) modeling to predict the effect of obesity and gastric bypass surgery on the pharmacokinetics and intragastric pH following omeprazole treatment. The simulated plasma concentrations closely matched the observed data from non-obese, morbidly obese, and post-gastric bypass populations. Obesity significantly reduces CYP3A4 and CYP2C19 activities, as reflected by the metabolic ratio [omeprazole sulphone]/[omeprazole] and [5-hydroxy-omeprazole]/[omeprazole]. The morbidly obese model accounted for the down-regulation of CYP2C19 and CYP3A4 to recapitulate the observed data. Sensitivity analysis showed that intestinal CYP3A4, gastric pH, small intestine bypass, and the delay in bile release do not have a major influence on omeprazole exposure. Hepatic CYP3A4 had a significant impact on the AUC of (S)-omeprazole, while hepatic CYP2C19 affected both (R)- and (S)-omeprazole AUC. After gastric bypass surgery, the activity of CYP3A4 and CYP2C19 is restored. The PBPK model was linked to a mechanism-based PD model to assess the effect of omeprazole on intragastric pH. Following 40 mg omeprazole, the mean intragastric pH was 4.3, 4.6, and 6.6 in non-obese, obese, and post-gastric bypass populations, and the daily time with pH >4 was 14.7, 16.4, and 24 h. Our PBPK/PD approach provides a comprehensive understating of the impact of obesity and weight loss on CYP3A4 and CYP2C19 activity and omeprazole pharmacokinetics. Given that simulated intragastric pH is relatively high in post-RYGB patients, irrespective of the dose of omeprazole, additional clinical outcomes are imperative to assess the effect of proton pump inhibitor in preventing marginal ulcers in this population.

Inhibitory Effect of Two Carbonic Anhydrases Inhibitors on the Activity of Major Cytochrome P450 Enzymes.

Both AW-9A (coumarin derivative) and WES-1 (sulfonamide derivative) were designed and synthesized as potential selective carbonic anhydrase inhibitors and were tested for anticancer activity. This study was undertaken to investigate their potential inhibitory effects on the major human cytochrome P450 (CYP) drug-metabolizing enzymes. Specific CYP probe substrates and validated analytical methods were used to measure the activity of the tested CYP enzymes. Furthermore, in silico simulations were conducted to understand how AW-9A and WES-1 bind to CYP2A6 at a molecular level. Molecular docking experiments were performed using the high-resolution X-ray structure, Protein Data Bank (PDB) ID: 2FDV for CYP2A6. CYP2E1-catalyzed chlorzoxazone-6'-hydroxylation was strongly inhibited by AW-9A and WES-1 with IC50 values of 0.084 µM and 0.101 µM, respectively. CYP2A6-catalyzed coumarin-7'-hydroxylation was moderately inhibited by AW-9A (IC50 = 4.2 µM). CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4 enzymes were weakly or negligibly inhibited by both agents. Docking studies suggest elevated potential to block the catalytic activity of CYP2A6. These findings point to the feasibility of utilizing these agents as promising chemopreventive agents (owing to inhibition of CYP2E1), and AW-9A as a smoking cessation aid (owing to inhibition of CYP2A6). Additional in-vivo studies should be conducted to examine the impact of CYP2A6 and CYP2E1 inhibition on drug interactions with probe substrates of these enzymes.

The Role of Intestinal Cytochrome P450s in Vitamin D Metabolism.

Vitamin D hydroxylation in the liver/kidney results in conversion to its physiologically active form of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]. 1,25(OH)2D3 controls gene expression through the nuclear vitamin D receptor (VDR) mainly expressed in intestinal epithelial cells. Cytochrome P450 (CYP) 24A1 is a catabolic enzyme expressed in the kidneys. Interestingly, a recently identified mutation in another CYP enzyme, CYP3A4 (gain-of-function), caused type III vitamin D-dependent rickets. CYP3A are also expressed in the intestine, but their hydroxylation activities towards vitamin D substrates are unknown. We evaluated CYP3A or CYP24A1 activities on vitamin D action in cultured cells. In addition, we examined the expression level and regulation of CYP enzymes in intestines from mice. The expression of CYP3A or CYP24A1 significantly reduced 1,25(OH)2D3-VDRE activity. Moreover, in mice, Cyp24a1 mRNA was significantly induced by 1,25(OH)2D3 in the intestine, but a mature form (approximately 55 kDa protein) was also expressed in mitochondria and induced by 1,25(OH)2D3, and this mitochondrial enzyme appears to hydroxylate 25OHD3 to 24,25(OH)2D3. Thus, CYP3A or CYP24A1 could locally attenuate 25OHD3 or 1,25(OH)2D3 action, and we suggest the small intestine is both a vitamin D target tissue, as well as a newly recognized vitamin D-metabolizing tissue.

Pregnane X receptor activation induces liver enlargement and regeneration and simultaneously promotes the metabolic activity of CYP3A1/2 and CYP2C6/11 in rats.

Human pregnane X receptor (PXR) is critical for regulating the expression of key drug-metabolizing enzymes such as CYP3A and CYP2C. Our recent study revealed that treatment with rodent-specific PXR agonist pregnenolone-16α-carbonitrile (PCN) significantly induced hepatomegaly and promoted liver regeneration after two-thirds partial hepatectomy (PHx) in mice. However, it remains unclear whether PXR activation induces hepatomegaly and liver regeneration and simultaneously promotes metabolic function of the liver. Here, we investigated the metabolism activity of CYP1A2, CYP3A1/2 and CYP2C6/11 during PXR activation-induced liver enlargement and regeneration in rats after cocktail dosing of CYP probe drugs. For PCN-induced hepatomegaly, a notable increase in the metabolic activity of CYP3A1/2 and CYP2C6/11, as evidenced by the plasma exposure of probe substrates and the AUC ratios of the characteristic metabolites to its corresponding probe substrates. The metabolic activity of CYP1A2, CYP3A1/2 and CYP2C6/11 decreased significantly after PHx. However, PCN treatment obviously enhanced the metabolic activity of CYP2C6/11 and CYP3A1/2 in PHx rats. Furthermore, the protein expression levels of CYP3A1/2 and CYP2C6/11 in liver were up-regulated. Taken together, this study demonstrates that PXR activation not only induces hepatomegaly and liver regeneration in rats, but also promotes the protein expression and metabolic activity of the PXR downstream metabolizing enzymes such as CYP3A1/2 and CYP2C6/11 in the body.

Drug-drug interaction between pachymic acid and repaglinide in rats and its potential mechanism

Both repaglinide and pachymic acid are useful for reducing blood glucose, but the drug interactions between them are not known. This study aimed to explore the effect of pachymic acid on the pharmacokinetics of repaglinide in rats and to elucidate its mechanism. The effects of pachymic acid (5 and 10 mg/kg) on the pharmacokinetics of repaglinide (0.5 mg/kg) were investigated in Sprague-Dawley rats (n = 6) with a single dose of repaglinide as a control. LC-MS/MS was used to determine the plasma concentration of repaglinide. Furthermore, the effect of pachymic acid on the metabolic stability of repaglinide and CYP3A4 activity was assessed in rat liver microsomes (RLMs). The co-administration of repaglinide and pachymic acid caused considerable changes in the pharmacokinetics of repaglinide, as shown by an increase in Cmax, t1/2, and AUC(0-t), and a decrease in CLz/F. The effect of pachymic acid was enhanced with increasing concentration. In vitro, pachymic acid showed a significant improvement of the metabolic stability of repaglinide in RLMs and inhibited the activity of CYP3A4. Co-administration of repaglinide with pachymic acid increased the systemic exposure of repaglinide and improved its metabolic stability in rats, which was mediated by CYP3A4. The results of animal studies cannot be directly applied to clinical practice, but concomitant administration of repaglinide and pachymic acid should be avoided or monitored until interaction studies are performed in humans.

Exploring the Impact of Efavirenz on Aflatoxin B1 Metabolism: Insights from a Physiologically Based Pharmacokinetic Model and a Human Liver Microsome Study.

Physiologically based pharmacokinetic (PBPK) models were utilized to investigate potential interactions between aflatoxin B1 (AFB1) and efavirenz (EFV), a non-nucleoside reverse transcriptase inhibitor drug and inducer of several CYP enzymes, including CYP3A4. PBPK simulations were conducted in a North European Caucasian and Black South African population, considering different dosing scenarios. The simulations predicted the impact of EFV on AFB1 metabolism via CYP3A4 and CYP1A2. In vitro experiments using human liver microsomes (HLM) were performed to verify the PBPK predictions for both single- and multiple-dose exposures to EFV. Results showed no significant difference in the formation of AFB1 metabolites when combined with EFV (0.15 µM) compared to AFB1 alone. However, exposure to 5 µM of EFV, mimicking chronic exposure, resulted in increased CYP3A4 activity, affecting metabolite formation. While co-incubation with EFV reduced the formation of certain AFB1 metabolites, other outcomes varied and could not be fully attributed to CYP3A4 induction. Overall, this study provides evidence that EFV, and potentially other CYP1A2/CYP3A4 perpetrators, can impact AFB1 metabolism, leading to altered exposure to toxic metabolites. The results emphasize the importance of considering drug interactions when assessing the risks associated with mycotoxin exposure in individuals undergoing HIV therapy in a European and African context.

A drug-drug interaction study and physiologically based pharmacokinetic modelling to assess the effect of an oral 5-lipoxygenase activating protein inhibitor on the pharmacokinetics of oral midazolam.

Early clinical studies have indicated that the pharmacokinetics of Atuliflapon (AZD5718) are time and dose dependent. The reason(s) for these findings is(are) not fully understood, but pre-clinical profiling suggests that time-dependent CYP3A4 inhibition cannot be excluded. In clinical practice, Atuliflapon will be co-administered with CYP3A4 substrates; thus, it is important to determine the impact of Atuliflapon on the pharmacokinetics (PK) of CYP3A4 substrates. The aim of this study was to evaluate the effect of Atuliflapon on the pharmacokinetics of a sensitive CYP3A4 substrate, midazolam, and to explore if the time-/dose-dependent effect seen after repeated dosing could be an effect of change in CYP3A4 activity. Open-label, fixed-sequence study in healthy volunteers to assess the PK of midazolam alone and in combination with Atuliflapon. Fourteen healthy male subjects received single oral dose of midazolam 2mg on days 1 and 7 and single oral doses of Atuliflapon (125 mg) from days 2 to 7. A physiologically based pharmacokinetic (PBPK) model was developed to assess this drug-drug interaction. Mean midazolam values of maximum plasma concentration (Cmax) and area under the curve (AUC) to infinity were increased by 39% and 56%, respectively, when co-administered with Atuliflapon vs. midazolam alone. The PBPK model predicted a 27% and 44% increase in AUC and a 23% and 35% increase in Cmax of midazolam following its co-administrations with two predicted therapeutically relevant doses of Atuliflapon. Atuliflapon is a weak inhibitor of CYP3A4; this was confirmed by the validated PBPK model. This weak inhibition is predicted to have a minor PK effect on CYP3A4 metabolized drugs.

Oral Drug Dosing After Gastric Bypass and Diet-Induced Weight Loss: Simpler Than We Think? Lessons Learned From the COCKTAIL Study.

This article summarizes the lessons learned from the COCKTAIL study: an open, three-armed, single-center study including patients with obesity scheduled for treatment with Roux-en-Y gastric bypass (RYGB) or nonsurgical calorie restriction, and a normal- to overweight control group. The clinical implications of the results from multiple peer-reviewed articles describing the effects of RYGB, severe caloric restriction, weight loss, and type 2 diabetes on the in vivo activity and protein expression of drug-metabolizing enzymes (cytochrome P450 (CYP) 1A2, 2C9, 2C19, and 3A) and transporters (DMETs; organic anion-transporting polypeptide (OATP) 1B1 and P-glycoprotein (P-gp)) are discussed in the perspective of three clinically relevant questions: (1) How should clinicians get the dose right in patients after RYGB? (2) Will drug disposition in patients with obesity be normalized after successful weight loss? (3) Are dose adjustments needed according to obesity and diabetes status? Overall, RYGB seems to have a lower impact on drug disposition than previously assumed, but clinicians should pay close attention to drugs with a narrow therapeutic range or where a high maximum drug concentration may be problematic. Whether obesity-related alterations of DMETs normalize with substantial weight loss depends on the DMET in question. Obesity and diabetes downregulate the in vivo activity of CYP2C19 and CYP3A (only obesity) but whether substrate drugs should be dose adjusted is also dependent on other factors that influence clearance, that is, liver blood flow and protein binding. Finally, we recommend frequent and individualized follow-up due to high inter- and intraindividual variability in these patients, particularly following RYGB.

Xin-yi-san contains potent human CYP1A2 inhibitors and its combined use with theophylline in treatment increases adverse risks in patients

BackgroundThe Xin-yi-san herbal decoction (XYS) is commonly used to treat patients with allergic rhinitis in Taiwan. Theophylline is primarily oxidized with high affinity by human cytochrome P450 (CYP)1A2, and has a narrow therapeutic index. PurposeThis study aimed to investigate the inhibition of human CYP1A2-catalyzed theophylline oxidation (THO) by XYS and its adverse effects in patients. MethodsHuman CYPs were studied in recombinant enzyme systems. The influence of concurrent XYS usage in theophylline-treated patients was retrospectively analyzed. ResultsAmong the major human hepatic and respiratory CYPs, XYS inhibitors preferentially inhibited CYP1A2 activity, which determined the elimination and side effects of theophylline. Among the herbal components of XYS decoction, Angelicae Dahuricae Radix contained potent THO inhibitors. Furanocoumarin imperatorin was abundant in XYS and Angelicae Dahuricae Radix decoctions, and non-competitively inhibited THO activity with Ki values of 77‒84 nM, higher than those (20‒52 nM) of fluvoxamine, which clinically interacted with theophylline. Compared with imperatorin, the intestinal bacterial metabolite xanthotoxol caused weaker THO inhibition. Consistent with the potency of the inhibitory effects, the docking analysis generated Gold fitness values in the order−fluvoxamine > imperatorin > xanthotoxol. During 2017‒2018, 2.6 % of 201,093 theophylline users consumed XYS. After inverse probability weighting, XYS users had a higher occurrence of undesired effects than non-XYS users; in particular, there was an approximately two-fold higher occurrence of headaches (odds ratio (OR), 2.14; 95 % confidence interval (CI), 1.99‒2.30; p < 0.001) and tachycardia (OR, 1.83; 95 % CI, 1.21‒2.77; p < 0.05). The incidence of irregular heartbeats increased (OR, 1.36; 95 % CI, 1.07‒1.72; p < 0.05) only in the theophylline users who took a high cumulative dose (≥ 24 g) of XYS. However, the mortality in theophylline users concurrently taking XYS was lower than that in non-XYS users (OR, 0.24; 95 % CI, 0.14‒0.40; p < 0.001). ConclusionXYS contains human CYP1A2 inhibitors, and undesirable effects were observed in patients receiving both theophylline and XYS. Further human studies are essential to reduce mortality and to adjust the dosage of theophylline in XYS users.

Efficient hepatocyte differentiation of primary human hepatocyte-derived organoids using three dimensional nanofibers (HYDROX) and their possible application in hepatotoxicity research

Human liver organoids are in vitro three dimensionally (3D) cultured cells that have a bipotent stem cell phenotype. Translational research of human liver organoids for drug discovery has been limited by the challenge of their low hepatic function compared to primary human hepatocytes (PHHs). Various attempts have been made to develop functional hepatocyte-like cells from human liver organoids. However, none have achieved the same level of hepatic functions as PHHs. We here attempted to culture human liver organoids established from cryopreserved PHHs (PHH-derived organoids), using HYDROX, a chemically defined 3D nanofiber. While the proliferative capacity of PHH-derived organoids was lost by HYDROX-culture, the gene expression levels of drug-metabolizing enzymes were significantly improved. Enzymatic activities of cytochrome P450 3A4 (CYP3A4), CYP2C19, and CYP1A2 in HYDROX-cultured PHH-derived organoids (Org-HYDROX) were comparable to those in PHHs. When treated with hepatotoxic drugs such as troglitazone, amiodarone and acetaminophen, Org-HYDROX showed similar cell viability to PHHs, suggesting that Org-HYDROX could be applied to drug-induced hepatotoxicity tests. Furthermore, Org-HYDROX maintained its functions for up to 35 days and could be applied to chronic drug-induced hepatotoxicity tests using fialuridine. Our findings demonstrated that HYDROX could possibly be a novel biomaterial for differentiating human liver organoids towards hepatocytes applicable to pharmaceutical research.

A 3D spheroid model of quadruple cell co-culture with improved liver functions for hepatotoxicity prediction

Drug-induced liver injury (DILI) is one of the major concerns during drug development. Wide acceptance of the 3 R principles and the innovation of in-vitro techniques have introduced various novel model options, among which the three-dimensional (3D) cell spheroid cultures have shown a promising prospect in DILI prediction. The present study developed a 3D quadruple cell co-culture liver spheroid model for DILI prediction via self-assembly. Induction by phorbol 12-myristate 13-acetate at the concentration of 15.42 ng/mL for 48 hours with a following 24-hour rest period was used for THP-1 cell differentiation, resulting in credible macrophagic phenotypes. HepG2 cells, PUMC-HUVEC-T1 cells, THP-1-originated macrophages, and human hepatic stellate cells were selected as the components, which exhibited adaptability in the designated spheroid culture conditions. Following establishment, the characterization demonstrated the competence of the model in long-term stability reflected by the maintenance of morphology, viability, cellular integration, and cell-cell junctions for at least six days, as well as the reliable liver-specific functions including superior albumin and urea secretion, improved drug metabolic enzyme expression and CYP3A4 activity, and the expression of MRP2, BSEP, and P-GP accompanied by the bile acid efflux transport function. In the comparative testing using 22 DILI-positive and 5 DILI-negative compounds among the novel 3D co-culture model, 3D HepG2 spheroids, and 2D HepG2 monolayers, the 3D culture method significantly enhanced the model sensitivity to compound cytotoxicity compared to the 2D form. The novel co-culture liver spheroid model exhibited higher overall predictive power with margin of safety as the classifying tool. In addition, the non-parenchymal cell components could amplify the toxicity of isoniazid in the 3D model, suggesting their potential mediating role in immune-mediated toxicity. The proof-of-concept experiments demonstrated the capability of the model in replicating drug-induced lipid dysregulation, bile acid efflux inhibition, and α-SMA upregulation, which are the key features of liver steatosis and phospholipidosis, cholestasis, and fibrosis, respectively. Overall, the novel 3D quadruple cell co-culture spheroid model is a reliable and readily available option for DILI prediction.

Association of CYP3A4*1B, CYP3A4*22 and CYP3A5*3 polymorphisms carriage with efficacy and safety of tamsulosin in patients with benign prostatic hyperplasia

Tamsulosin is a first-line drug in the treatment of lower urinary tract symptoms (LUTS) in benign prostatic hyperplasia (BPH). Despite high estimates of its efficacy and safety, it rates may vary due to genetic polymorphisms of genes for the enzymes involved in the drugs metabolism.The aim of the work was to evaluate the carriage influence of genes polymorphisms of the CYP3A enzymes group of tamsulosin metabolizers on the efficacy and safety of therapy in patients with LUTS in BPH.Materials and methods. A total of 142 patients with LUTS, with an established BPH diagnosis (N40 according to ICD-10) were included in the study and underwent all stages. All patients received monotherapy with tamsulosin 0.4 mg/day for at least 8 weeks. An IPSS questionnaire with the definition of quality of life, a prostate ultrasound with the determination of the prostate volume and residual urine, as well as uroflowmetry, were used to evaluate the results of the treatment. Controls were performed at 2, 4 and 8 weeks from the start of the therapy. The carriage of polymorphic markers CYP3A4 (*1B, *22) and CYP3A5*3 was determined in patients; HPLC was used to determine drug concentrations in blood plasma and levels of cortisol and its metabolite 6-beta-hydroxycortisol in urine to assess the phenotypic activity of CYP3A.Results. No statistically significant associations between CYP3A phenotype (defined by CYP3A4 and CYP3A5 genotypes) and clinical parameters of the tamsulosin therapy efficacy and the safety assessment in the studied sample of patients were found (p &gt;0.05). Similar data were obtained for individual variants of CYP3A4*1B, CYP3A4*22, CYP3A5*3 (p &gt;0.05). The comparison of the tamsulosin residual equilibrium concentration values in patients in the study sample with respect to the carriers of CYP3A4 and CYP3A5 gene variants did not reveal the presence of significant differences in either CYP3A phenotypes and carriers and non-carriers of individual CYP3A4*1B (p=0.57), CYP3A4*22 (p=0.37) and CYP3A5*3 (p=0.76) variants. No association was found between the metabolic ratio of 6-beta-hydroxycortisol / cortisol in urine and the CYP3A phenotype encoded by a combination of genotypes of CYP3A4 and CYP3A5 gene variants (p &gt;0.05).Conclusion. A possible association between the carriage of CYP3A4*1B, CYP3A4*22, CYP3A5*3 variants, a CYP3A activity assessed by the content of an endogenous substrate of this isoenzyme and its metabolite in urine, the level of plasma concentration of the drug, and the efficacy and safety of tamsulosin, has not been confirmed. The contribution of CYP3A4 and CYP3A5 genetic polymorphisms to clinical parameters of the tamsulosin therapy requires a further study.

Lack of CYP3A4 protein induction despite mRNA induction in primary hepatocytes exposed to rifabutin as a possible explanation for its low interaction risk in vivo.

Rifampicin is a strong inducer of cytochrome P450 (CYP3A4) and P-glycoprotein (P-gp/ABCB1), leading to profound drug-drug interactions. In contrast, the chemically related rifabutin does not show such pronounced induction properties in vivo. The aim of our study was to conduct a comprehensive analysis of the different induction potentials of rifampicin and rifabutin in primary human hepatocytes and to analyze the mechanism of potential differences. Therefore, we evaluated CYP3A4/ABCB1 mRNA expression (polymerase chain reaction), CYP3A4/P-gp protein expression (immunoaffinity-liquid chromatography-mass spectrometry, IA-LC-MS/MS), CYP3A4 activity (testosterone hydroxylation), and considered intracellular drug uptake after treatment with increasing rifamycin concentrations (0.01-10µM). Furthermore, rifamycin effects on the protein levels of CYP2C8, CYP2C9, and CYP2C19 were analyzed (IA-LC-MS/MS). Mechanistic analysis included the evaluation of possible suicide CYP3A4 inhibition (IC50 shift assay) and drug impact on translational efficiency (cell-free luminescence assays). Rifabutin accumulated 6- to 15-fold higher in hepatocytes than rifampicin, but induced CYP3A4 mRNA comparably to rifampicin (e. g. rifampicin 61-fold vs. rifabutin 44-fold, 72h). While rifampicin for example enhanced protein (10µM: 21-fold) and activity levels considerably (53-fold), rifabutin only slightly increased CYP3A4 protein expression (10µM: 3.3-fold) or activity (11-fold) compared to rifampicin after 72h. Both rifamycins similarly influenced expression of other eliminating proteins. A potential CYP3A4 suicide inhibition by a specific rifabutin metabolite or disruption of ribosome function were excluded experimentally. In conclusion, the lack of protein enhancement, could explain rifabutin's weaker induction-related drug-drug interaction risk in vivo.

Effects of two commonly used antidepressants amitriptyline and fluoxetine on the pharmacokinetics of abrocitinib in rats

Abrocitinib is approved to treat moderate-to-severe atopic dermatitis and eliminated mainly through cytochrome P450 (CYP450) enzyme. Two commonly used antidepressants, amitriptyline and fluoxetine, could inhibit the activities of CYP2C19 and CYP3A4. In this study, we developed a new and quick ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for quantitatively analyzing the plasma concentration of abrocitinib, and further investigated the effects of amitriptyline or fluoxetine on the pharmacokinetics of abrocitinib in rats. The selectivity, linearity, recovery, accuracy, precision, matrix effect and stability of UPLC-MS/MS assay were satisfied according to the United States Food and Drug Administration (FDA) and European Medicines Agency (EMA) guidelines. Our result showed that when co-administered with amitriptyline and fluoxetine, the CLz/F of abrocitinib was reduced by 44.4 % and 33.3 %, respectively, while the AUC(0–t) of abrocitinib was increased by 77.7 % and 49.4 %, respectively. It indicated that amitriptyline and fluoxetine could significantly increase the plasma concentration of abrocitinib in rats. Thus, dose adjustment of abrocitinib may be required when it is combined with amitriptyline or fluoxetine in ongoing clinical practice.

LC-HRMS and GC-MS Profiling of Urine Free Cortisol, Cortisone, 6Β-, and 18-Hydroxycortisol for the Evaluation of Glucocorticoid and Mineralocorticoid Disorders.

Urine free cortisol measurements are routinely performed to evaluate hypercortisolism. Despite their analytical inaccuracy, immunoassay-based methods are frequently used. Advances in liquid chromatography-high-resolution mass spectrometry (LC-HRMS) facilitate the incorporation of powerful diagnostic tools into clinical laboratories. In addition to its high analytical specificity and simultaneous analysis of different metabolites, accurate mass measurement allows for untargeted compound identification, which may help to identify clinically relevant metabolites or drugs. The present study aimed to validate a simple routine LC-HRMS method to quantify cortisol, cortisone, 6β-hydroxycortisol, and 18-hydroxycortisol simultaneously in human urine. Additionally, the study also validated a GC-MS method for the same steroids, evaluated their cross-reactivity with commercial cortisol immunoassays, and quantified the 24 h urine excretion in patients under clinical suspicion or follow-up for hypercortisolism. The LC-HRMS method involved liquid-liquid extraction using dichloromethane, micro-LC for chromatographic separation and detection using the accurate masses of the steroids, and simultaneous high-resolution full scan acquisition. The method presented acceptable linearity, precision, and accuracy. Significant interference from 6β-hydroxycortisol and cortisone was demonstrated in the cortisol immunoassays, which impacted their reliability in the follow-up of patients with hypercortisolism and significant changes in these cortisol metabolites (i.e., due to drug-induced changes in CYP3A4 activity). A rapid and accurate routine LC-HRMS method was validated, which is useful for the evaluation of hypercortisolism and other disorders of glucocorticoid and mineralocorticoid metabolism.