Polymorphism of human cytochrome P450 enzymes and its clinical impact

Reviewing Data Integrated for PBPK Model Development to Predict Metabolic Drug-Drug Interactions: Shifting Perspectives and Emerging Trends

Physiologically-based pharmacokinetics (PBPK) modeling is a robust tool that supports drug development and the pharmaceutical industry and regulatory authorities. Implementation of predictive systems in the clinics is more than ever a reality, resulting in a surge of interest for PBPK models by clinicians. We aimed to establish a repository of available PBPK models developed to date to predict drug-drug interactions (DDIs) in the different therapeutic areas by integrating intrinsic and extrinsic factors such as genetic polymorphisms of the cytochromes or environmental clues. This work includes peer-reviewed publications and models developed in the literature from October 2017 to January 2021. Information about the software, type of model, size, and population model was extracted for each article. In general, modeling was mainly done for DDI prediction via Simcyp^® software and Full PBPK. Overall, the necessary physiological and physio-pathological parameters, such as weight, BMI, liver or kidney function, relative to the drug absorption, distribution, metabolism, and elimination and to the population studied for model construction was publicly available. Of the 46 articles, 32 sensibly predicted DDI potentials, but only 23% integrated the genetic aspect to the developed models. Marked differences in concentration time profiles and maximum plasma concentration could be explained by the significant precision of the input parameters such as Tissue: plasma partition coefficients, protein abundance, or Ki values. In conclusion, the models show a good correlation between the predicted and observed plasma concentration values. These correlations are all the more pronounced as the model is rich in data representative of the population and the molecule in question. PBPK for DDI prediction is a promising approach in clinical, and harmonization of clearance prediction may be helped by a consensus on selecting the best data to use for PBPK model development.

The role of DMPK science in improving pharmaceutical research and development efficiency

The successful regulatory authority approval rate of drug candidates in the drug development pipeline is crucial for determining pharmaceutical research and development (R&D) efficiency. Regulatory authorities include the US Food and Drug Administration (FDA), European Medicines Agency (EMA), and Pharmaceutical and Food Safety Bureau Japan (PFSB), among others. Optimal drug metabolism and pharmacokinetics (DMPK) properties influence the progression of a drug candidate from the preclinical to the clinical phase. In this review, we provide a comprehensive assessment of essential concepts, methods, improvements, and challenges in DMPK science and its significance in drug development. This information provides insights into the association of DMPK science with pharmaceutical R&D efficiency.

Pharmacokinetics and Toxicokinetics of Artemisinin-Hydroxychloroquine Sulfate Tablets in Rats and Dogs

Artemisinin-hydroxychloroquine sulfate tablets (AH) are relatively inexpensive and a novel combination therapy for the treatment of all forms of malaria, especially aminoquinine drug-resistant strains of P. falciparum. Our aim was to assess the pharmacokinetics (PK) and toxicokinetics (TK) of AH following oral administration in Sprague Dawley rats and Beagle dogs by using the liquid chromatography tandem mass spectrometry methods (LC-MS/MS). The PK studies were carried out in eighteen rats at three doses and six dogs at three rounds of three doses after a single oral administration of AH. The TK studies in rats and dogs were accompanied by the 14-day repeated dosing studies. The PK results revealed that artemisinin was absorbed and cleared rapidly in rats with obvious gender difference and interindividual variability, and the systemic exposure with regard to AUC was positively correlated with the dosage in female rats. However, the kinetics parameters of artemisinin in dogs were not obtained because the plasma concentration was undetectable. The absorption and elimination of hydroxychloroquine in dogs and rats were relatively slow, and no gender difference was observed. The AUC of hydroxychloroquine showed a linear correlation with the dosage, but C _max varied significantly among individuals. After 14-day repeated oral administration of AH, hydroxychloroquine shows an increase in systemic exposure and accumulation in rats and dogs, whereas the AUC and C _max of artemisinin remarkably decreased in female rats due to its autoinduction metabolism. The TK results were basically consistent with the dose- and time-dependent toxic reaction in 14-day repeated dosing studies of AH in rats and dogs. The information from our studies could be helpful for further pharmacological and toxicological research and clinical application of AH.

Protocol for a pharmacogenetic study of antidepressants: characterization of drug-metabolizing profiles of cytochromes CYP2D6 and CYP2C19 in a Sardinian population of patients with major depressive disorder

The effectiveness of antidepressants shows high interindividual variability ranging from full symptomatologic remission to treatment-resistant depression. Many factors can determine the variation in the clinical response, but a fundamental role is played by genetic variation within the genes encoding for the enzymes most involved in the metabolism of antidepressant drugs: the CYP2D6 and CYP2C19 isoforms of the cytochrome P450 system. This study is poised to clarify whether the different metabolizing phenotypes related to CYP2D6 and CYP2C19 could have an impact on the clinical efficacy of antidepressants and whether the frequency of these phenotypes of metabolization shows differences in the population of Sardinian patients compared to other Caucasian populations. The sample is being recruited from patients followed-up and treated at the Psychiatric Unit of the Department of Medical Science and Public Health, University of Cagliari and the University Hospital Agency of Cagliari (Italy). The study design includes three approaches: (1) a pharmacogenetic analysis of 80 patients diagnosed with MDD resistant to antidepressant treatment compared to 80 clinically responsive or remitted patients; (2) a prospective arm (N = 30) of the study where we will test the impact of genetic variation within the CYP2D6 and CYP2C19 genes on clinical response to antidepressants and on their serum levels and (3) the assessment of the socio-economic impact of antidepressant therapies, and estimation of the cost-effectiveness of the pharmacogenetic test based on CYP genes.

Therapeutic Drug Monitoring of Psychotropics as a Diagnostic Tool for CYP2D6 Poor Metabolizer Phenotype

BACKGROUND

Interpatient variability in cytochrome P450 2D6 (CYP2D6) enzyme activity alters the serum concentrations of most psychotropics, which often have narrow therapeutic indices. Therefore, preemptive knowledge of CYP2D6 activity is desired. However, accessible indicators for deficient CYP2D6 activity are necessary because genotyping all patients prescribed CYP2D6 metabolized drugs is often not feasible or cost-effective.

METHODS

In this study, the predictive value of the ratio between a CYP2D6 substrate and its metabolite, known as the metabolic ratio (MR), the dose-corrected serum concentration of substrate (CDR), and the dose-corrected sum concentration of substrate and metabolite (Sum CDR) of venlafaxine, risperidone, aripiprazole, and nortriptyline were determined to predict the CYP2D6 poor metabolizer (PM) phenotype. The area-under-the-receiver operator characteristic curve, as well as the sensitivity, specificity, and positive and negative predictive values of the optimal thresholds, were calculated.

RESULTS

Although the MR, CDR, and Sum CDR all predicted the CYP2D6 PM phenotype, the predictive value of the MR was most robust for venlafaxine and aripiprazole, and the Sum CDR was inferior for all 3 psychotropics. MRs of venlafaxine, risperidone, and aripiprazole, and CDR of nortriptyline showed an area-under-the-receiver operator characteristics (95% confidence interval) of 97.2% (94.7%-99.6%), 93.0% (88.8%-97.2%), 97.8% (95.4%-100.0%), and 85.6% (78.0%-93.1%), respectively. Thresholds of the log(MR) of ≥0.1 for venlafaxine, ≥0.0 for risperidone, and ≥1.5 for aripiprazole, and log(CDR) ≥0.5 for nortriptyline produced >92% sensitivity and >64% specificity.

CONCLUSIONS

If therapeutic drug monitoring is available, the thresholds presented here could serve as a diagnostic tool for the CYP2D6 PM phenotype of psychiatric patients prescribed the aforementioned psychotropic medications.

Bioprinting of Human Liver-Derived Epithelial Organoids for Toxicity Studies

There is a need for long-lived hepatic in vitro models to better predict drug induced liver injury (DILI). Human liver-derived epithelial organoids are a promising cell source for advanced in vitro models. Here, organoid technology is combined with biofabrication techniques, which holds great potential for the design of in vitro models with complex and customizable architectures. Here, porous constructs with human hepatocyte-like cells derived from organoids are generated using extrusion-based printing technology. Cell viability of bioprinted organoids remains stable for up to ten days (88-107% cell viability compared to the day of printing). The expression of hepatic markers, transporters, and phase I enzymes increased compared to undifferentiated controls, and is comparable to non-printed controls. Exposure to acetaminophen, a well-known hepatotoxic compound, decreases cell viability of bioprinted liver organoids to 21-51% (p < 0.05) compared to the start of exposure, and elevated levels of damage marker miR-122 are observed in the culture medium, indicating the potential use of the bioprinted constructs for toxicity testing. In conclusion, human liver-derived epithelial organoids can be combined with a biofabrication approach, thereby paving the way to create perfusable, complex constructs which can be used as toxicology- and disease-models.

Differential Interactions of Selected Phytocannabinoids with Human CYP2D6 Polymorphisms

Cytochrome P450 2D6 (CYP2D6) is primarily expressed in the liver and in the central nervous system. It is known to be highly polymorphic in nature. It metabolizes several endogenous substrates such as anandamide (AEA). Concomitantly, it is involved in phase 1 metabolism of several antidepressants, antipsychotics, and other drugs. Research in the field of phytocannabinoids (pCBs) has recently accelerated owing to their legalization and increasing medicinal use for pain and inflammation. The primary component of cannabis is THC, which is well-known for its psychotropic effects. Since CYP2D6 is an important brain and liver P450 and is known to be inhibited by CBD, we investigated the interactions of four important highly prevalent CYP2D6 polymorphisms with selected phytocannabinoids (CBD, THC, CBDV, THCV, CBN, CBG, CBC, β-carophyllene) that are rapidly gaining popularity. We show that there is differential binding of CYP2D6*17 to pCBs as compared to WT CYP2D6. We also perform a more detailed comparison of WT and *17 CYP2D6, which reveals the possible regulation of AEA metabolism by CBD. Furthermore, we use molecular dynamics to delineate the mechanism of this binding, inhibition, and regulation. Taken together, we have found that the interactions of CYP2D6 with pCBs vary by polymorphism and by specific pCB class.

Oral Yohimbine as a New Probe Drug to Predict CYP2D6 Activity: Results of a Fixed-Sequence Phase I Trial

Objective

Yohimbine pharmacokinetics were determined after oral administration of a single oral dose of yohimbine 5 mg and a microdose of yohimbine 50 µg in relation to different cytochrome P450 (CYP) 2D6 genotypes. The CYP2D6 inhibitor paroxetine was used to investigate the influence on yohimbine pharmacokinetics. Microdosed midazolam was applied to evaluate a possible impact of yohimbine on CYP3A activity and the possibility of combining microdosed yohimbine and midazolam to simultaneously determine CYP2D6 and CYP3A activity.

Methods

In a fixed-sequence clinical trial, 16 healthy volunteers with a known CYP2D6 genotype [extensive (10), intermediate (2) and poor (4) metaboliser] received an oral dose of yohimbine 50 µg, yohimbine 5 mg at baseline and during paroxetine as a CYP2D6 inhibitor. Midazolam (30 µg) was co-administered to determine CYP3A activity at each occasion. Plasma concentrations of yohimbine, its main metabolite 11-OH-yohimbine, midazolam and paroxetine were quantified using validated liquid chromatography-tandem mass spectrometry assays.

Results

Pharmacokinetics of yohimbine were highly variable and a CYP2D6 genotype dependent clearance was observed. After yohimbine 5 mg, the clearance ranged from 25.3 to 15,864 mL/min and after yohimbine 50 µg, the clearance ranged from 39.6 to 38,822 mL/min. A more than fivefold reduction in clearance was caused by paroxetine in CYP2D6 extensive metabolisers, while the clearance in poor metabolisers was not affected. Yohimbine did not alter CYP3A activity as measured by microdosed midazolam.

Conclusions

The pharmacokinetics of yohimbine were highly correlated with CYP2D6, which was further supported by the clearance inhibition caused by the CYP2D6 inhibitor paroxetine. With these data, yohimbine is proposed to be a suitable probe drug to predict CYP2D6 activity. In addition, the microdose can be used in combination with microdosed midazolam to simultaneously evaluate CYP2D6 and CYP3A activity without any interaction between the probe drugs and because the microdoses exert no pharmacological effects.

Clinical Trial Registration

EudraCT2017-001801-34.

Electronic supplementary material

The online version of this article (10.1007/s40262-020-00862-6) contains supplementary material, which is available to authorized users.

Optimization of Nutrition And Medication (OptiNAM) for acutely admitted older patients: protocol for a randomized single-blinded controlled trial

BACKGROUND

Internationally, older patients (≥65 years) account for more than 40% of acute admissions. Older patients admitted to the emergency department (ED) are frequently malnourished and exposed to inappropriate medication prescribing, due in part to the inaccuracy of creatinine-based equations for estimated glomerular filtration rate (eGFR). The overall aims of this trial are to investigate: (1) the efficacy of a medication review (MED intervention) independent of nutritional status, (2) the accuracy of eGFR equations based on various biomarkers compared to measured GFR (mGFR) based on ^99mTechnetium-diethylenetriaminepentaacetic acid plasma clearance, and (3) the efficacy of an individualized multimodal and transitional nutritional intervention (MULTI-NUT-MED intervention) in older patients with or at risk of malnutrition in the ED.

METHODS

The trial is a single-center block randomized, controlled, observer-blinded, superiority and explorative trial with two parallel groups. The population consists of 200 older patients admitted to the ED: 70 patients without malnutrition or risk of malnutrition and 130 patients with or at risk of malnutrition defined as a Mini Nutritional Assessment-Short Form score ≤11. All patients without the risk of malnutrition receive the MED intervention, which consists of a medication review by a pharmacist and geriatrician in the ED. Patients with or at risk of malnutrition receive the MULTI-NUT-MED intervention, which consists of the MED intervention in addition to, dietary counseling and individualized interventions based on the results of screening tests for dysphagia, problems with activities of daily living, low muscle strength in the lower extremities, depression, and problems with oral health. Baseline data are collected upon study inclusion, and follow-up data are collected at 8 and 16 weeks after discharge. The primary outcomes are (1) change in medication appropriateness index (MAI) score from baseline to 8 weeks after discharge, (2) accuracy of different eGFR equations compared to mGFR, and (3) change in health-related quality of life (measured with EuroQol-5D-5L) from baseline to 16 weeks after discharge.

DISCUSSION

The trial will provide new information on strategies to optimize the treatment of malnutrition and inappropriate medication prescribing among older patients admitted to the ED.

TRAIL REGISTRATION

ClinicalTrials.gov NTC03741283 . Retrospectively registered on 14 November 2018.

The Reduction of the Combined Effects of Aflatoxin and Ochratoxin A in Piglet Livers and Kidneys by Dietary Antioxidants

The purpose of this study was to investigate the combined effects of aflatoxin B1 and ochratoxin A on protein expression and catalytic activities of CYP1A2, CYP2E1, CYP3A29 and GSTA1 and the preventive effect of dietary byproduct antioxidants administration against these mycotoxin damage. Three experimental groups (E1, E2, E3) and one control group (C) of piglets after weaning (TOPIGS-40 hybrid) were fed with experimental diets for 30 days. A basal diet containing normal compound feed for starter piglets was used as a control treatment and free of mycotoxin. The experimental groups were fed as follows: E1—basal diet plus a mixture (1:1) of two byproducts (grapeseed and sea buckthorn meal), E2—the basal diet experimentally contaminated with mycotoxins (479 ppb OTA and 62ppb AFB1) and E3—basal diet containing 5% of the mixture (1:1) of grapeseed and sea buckthorn meal and contaminated with the mix of OTA and AFB1. After 4 weeks, the animals were slaughtered, and tissue samples were taken from liver and kidney in order to perform microsomal fraction isolation, followed by protein expression and enzymatic analyses. The protein expressions of CYP2E1 and CYP3A29 were up-regulated in an insignificant manner in liver, whereas in kidney, those of CYP1A2, CYP2E1 and CYP3A29 were down-regulated. The enzymatic activities of CYP1A2, CYP2E1 and CYP3A29 decreased in liver, in a significant manner, whereas in kidney, these increased significantly. The co-presence of the two mycotoxins and the mixture of grape seed and sea buckthorn meal generated a tendency to return to the control values, which suggest that grapeseed and sea buckthorn meal waste represent a promising source in counteracting the harmful effect of ochratoxin A and aflatoxin B.

Ilexsaponin A1: In vitro metabolites identification and evaluation of inhibitory drug-drug interactions

As a triterpene saponin, ilexsaponin A1 is one of the most abundant, representative and active components in plants of Ilex pubescens, used in the treatment of cardiovascular diseases. This study aimed to identify the metabolites of ilexsaponin A1 and evaluate its in vitro inhibitory drug-drug interaction (DDI) potential by using human liver microsomes (HLM) and cytochrome P450 enzymes (CYPs)-specific probes, with all the qualitative and quantitative analysis performed by LC-MS/MS. As a result, two metabolites generated through the metabolic pathways of glucuronic acid conjugation and glucose conjugation were first time detected in the HLM. An inhibitory DDI evaluating system consisting of 7 major CYP enzymes involving 8 CYP-catalyzed reactions was established, validated and then used for the DDI evaluation. Our data suggested ilexsaponin A1 and its metabolite, ilexgenin A, are not direct or mechanism-based inhibitors of CYP1A2, 2B6, 2C8, 2C9, 2D6, 2E1 or 3A4/5 at 0.05-10 μM. A significant decreased remaining activity of CYP2B6 (from 77.89 % to 23.19 %) was observed in a dose-dependent manner when increased the concentration of ilexsaponin A1 from 50 to 500 μM. Collectively, our data demonstrate ilexsaponin A1 is unlikely to cause DDIs by inhibiting co-administered drugs metabolized by these CYP enzymes.

Polymorphisms in genes related to oxidative stress and inflammation: Emerging links with the pathogenesis and severity of Cerebral Cavernous Malformation disease

Cerebral Cavernous Malformation (CCM) is a cerebrovascular disease of genetic origin affecting 0.5% of the population and characterized by abnormally enlarged and leaky capillaries that predispose to seizures, neurological deficits, and intracerebral hemorrhage (ICH). CCM occurs sporadically or is inherited as dominant condition with incomplete penetrance and highly variable expressivity. Three disease genes have been identified: KRIT1 (CCM1), CCM2 and CCM3. Previous results demonstrated that loss-of-function mutations of CCM genes cause pleiotropic effects, including defective autophagy, altered reactive oxygen species (ROS) homeostasis, and enhanced sensitivity to oxidative stress and inflammatory events, suggesting a novel unifying pathogenetic mechanism, and raising the possibility that CCM disease onset and severity are influenced by the presence of susceptibility and modifier genes. Consistently, genome-wide association studies (GWAS) in large and homogeneous cohorts of patients sharing the familial form of CCM disease and identical mutations in CCM genes have led to the discovery of distinct genetic modifiers of major disease severity phenotypes, such as development of numerous and large CCM lesions, and susceptibility to ICH. This review deals with the identification of genetic modifiers with a significant impact on inter-individual variability in CCM disease onset and severity, including highly polymorphic genes involved in oxidative stress, inflammatory and immune responses, such as cytochrome P450 monooxygenases (CYP), matrix metalloproteinases (MMP), and Toll-like receptors (TLR), pointing to their emerging prognostic value, and opening up new perspectives for risk stratification and personalized medicine strategies.

Host bioenergetic parameters reveal cytotoxicity of anti-tuberculosis drugs undetected using conventional viability assays

High attrition rates in tuberculosis (TB) drug development have been largely attributed to safety, which is likely due to the use of endpoint assays measuring cell viability to detect drug cytotoxicity. In drug development for cancer, metabolic, and neurological disorders and for antibiotics, cytotoxicity is increasingly being assessed using extracellular flux (XF) analysis, which measures cellular bioenergetic metabolism in real time. Here, we adopt the XF platform to investigate the cytotoxicity of drugs currently used in TB treatment on the bioenergetic metabolism of HepG2 cells, THP-1 macrophages, and human monocyte-derived macrophages (hMDMs). We found that the XF analysis reveals earlier drug-induced effects on the cells’ bioenergetic metabolism prior to cell death, measured by conventional viability assays. Furthermore, each cell type has a distinct response to drug treatment, suggesting that more than one cell type should be considered to examine cytotoxicity in TB drug development. Interestingly, chemically unrelated drugs with different modes of action on Mycobacterium tuberculosis have similar effects on the bioenergetic parameters of the cells, thus discouraging the prediction of potential cytotoxicity based on chemical structure and mode of action of new chemical entities. The clustering of the drug-induced effects on the hMDM bioenergetic parameters are reflected in the clustering of the effects of the drugs on cytokine production in hMDMs, demonstrating concurrence between the effects of the drugs on the metabolism and functioning of the macrophages. These findings can be used as a benchmark to establish XF analysis as a new tool to assay cytotoxicity in TB drug development.

Effects of paeoniflorin on the activities and mRNA expression of rat CYP1A2, CYP2C11 and CYP3A1 enzymes in vivo

Paeoniflorin is the major constituent in extracts of the paeony root, the purpose of the present study was to assess the effects of paeoniflorin on the activities and mRNA expression of the rat hepatic drug-metabolizing enzymes cytochrome P450 (CYP1A2), CYP2C11 and CYP3A1 in vivo.Sprague-Dawley (SD) male rats were treated with paeoniflorin at the dosage of 25, 50 and 100 mg/kg or 0.9% sodium chloride solution by intragastric administration for 7 days, then were given probe drugs phenacetin (CYP1A2), tolbutamide (CYP2C11), or midazolam (CYP3A1) orally on the eighth day. Blood samples were collected at various times, and the plasma concentrations of the probe drugs were estimated with ultra-high-performance liquid chromatography. The mRNA expression levels of rat hepatic CYP1A2, CYP2C11 and CYP3A1 were analysed with real-time PCR.The pharmacokinetic results indicated that paeoniflorin inhibits the activities of CYP1A2, CYP2C11 and CYP3A1 in vivo. The effect was most pronounced on CYP3A1, according to the United States Food and Drug Administration classification of inhibitors of CYP3A, it reached the category of moderate inhibition. The mRNA expression levels of 3 CYP enzymes were also tended to be inhibited.We conclude that paeoniflorin can inhibit the activities of CYP1A2, CYP2C11 and CYP3A1 in vivo, which may affect the metabolism of drugs that are primarily dependent on these pathways.

Impacts of caffeine on resistant chicken's performance and cardiovascular gene expression

We previously reported a study on 288 broiler (Gallus gallus) chicks who received caffeine in water between days 3 and 42, at levels of 0, 6.25, 12.5, 25, 50 and 100 mg/kg body weight (BW)/day. In the previous report, we found that caffeine caused pulmonary hypertension (PH)-associated mortality in a significant minority (20%-30%) of birds, including right ventricular hypertrophy and ascites. We have also shown a significant upregulation of the serotonin transporter (SERT), troponin T2, adenosine A₁ receptor (ADORA1) and phosphodiesterase 5A (PDE5) in chicken suffering from PH. Here, we examine the resistant (survived) chicks from the first study that had not died due to acute heart failure and did not have clinical signs of pulmonary hypertension. Our goal was to determine whether birds who lacked overt signs of disease had subclinical manifestations, including similar changes in gene expression, growth rates and altered systemic haemodynamics. We found that growth was significantly increased by caffeine consumption (p < 0.01) at low doses; however, dosage over 50 mg/BW/d had remarkable adverse effects on growth (p < 0.01). Blood pressure, troponin T2 and PDE5 gene expression were not significantly altered by caffeine administration (p > 0.05). However, SERT gene expression linearly increased with increasing caffeine dosage (p < 0.01). The impact of caffeine on ADORA1 gene expression was dose dependent and nonlinear. In conclusion, despite the significant effects of caffeine on birds' growth, no significant negative effects of caffeine were observed on the cardiovascular function of resistant chickens. This work provides valuable information for further study on different dosage of caffeine in an animal model.

Functional Characterization of 21 Rare Allelic CYP1A2 Variants Identified in a Population of 4773 Japanese Individuals by Assessing Phenacetin O-Deethylation

Cytochrome P450 1A2 (CYP1A2), which accounts for approximately 13% of the total hepatic cytochrome content, catalyzes the metabolic reactions of approximately 9% of frequently used drugs, including theophylline and olanzapine. Substantial inter-individual differences in enzymatic activity have been observed among patients, which could be caused by genetic polymorphisms. Therefore, we functionally characterized 21 novel CYP1A2 variants identified in 4773 Japanese individuals by determining the kinetic parameters of phenacetin O-deethylation. Our results showed that most of the evaluated variants exhibited decreased or no enzymatic activity, which may be attributed to potential structural alterations. Notably, the Leu98Gln, Gly233Arg, Ser380del Gly454Asp, and Arg457Trp variants did not exhibit quantifiable enzymatic activity. Additionally, three-dimensional (3D) docking analyses were performed to further understand the underlying mechanisms behind variant pharmacokinetics. Our data further suggest that despite mutations occurring on the protein surface, accumulating interactions could result in the impairment of protein function through the destabilization of binding regions and changes in protein folding. Therefore, our findings provide additional information regarding rare CYP1A2 genetic variants and how their underlying effects could clarify discrepancies noted in previous phenotypical studies. This would allow the improvement of personalized therapeutics and highlight the importance of identifying and characterizing rare variants.

Classification of drugs for evaluating drug interaction in drug development and clinical management

During new drug development, clinical drug interaction studies are carried out in accordance with the mechanism of potential drug interactions evaluated by in vitro studies. The obtained information should be provided efficiently to medical experts through package inserts and various information materials after the drug's launch. A recently updated Japanese guideline presents general procedures that are considered scientifically valid at the present moment. In this review, we aim to highlight the viewpoints of the Japanese guideline and enumerate drugs that were involved or are anticipated to be involved in evident pharmacokinetic drug interactions and classify them by their clearance pathway and potential intensity based on systematic reviews of the literature. The classification would be informative for designing clinical studies during the development stage, and the appropriate management of drug interactions in clinical practice.

Global spectrum of population-specific common missense variation in cytochrome P450 pharmacogenes

Next-generation sequencing technology has afforded the discovery of many novel variants that are of significance to inheritable pharmacogenomics (PGx) traits but a large proportion of them have unknown consequences. These include missense variants resulting in single amino acid substitutions in cytochrome P450 (CYP) proteins that can impair enzyme function, leading to altered drug efficacy and toxicity. While most unknown variants are rare, an overlooked minority are variants that are collectively rare but enriched in specific populations. Here, we analyzed sequence variation data in 141,456 individuals from across eight study populations in gnomAD for 38 CYP genes to identify such variants in addition to common variants. By further comparison with data from two PGx-specific databases (PharmVar and PharmGKB) and ClinVar, we identified 234 missense variants in 35 CYP genes, of which 107 were unknown to these databases. Most unknown variants (n = 83) were population-specific common variants and several (n = 7) were found in important CYP pharmacogenes (CYP2D6, CYP4F2, and CYP2C19). Overall, 29% (n = 31) of 107 unknown variants were predicted to affect CYP enzyme function although further biochemical characterization is necessary. These variants may elucidate part of the unexplained interpopulation differences observed in drug response.

Influence of CYP2C9 Genetic Polymorphisms on the Pharmacokinetics of Losartan and Its Active Metabolite E-3174: A Systematic Review and Meta-Analysis

This study aimed to investigate the influence of CYP2C9 genetic polymorphisms on the pharmacokinetics of losartan and its active metabolite, E-3174, through a systematic review and meta-analysis. Eight studies published before March 2021 were included in this study. We used PubMed, the Cochrane Library, EMBASE, and Web of Science, based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The data analysis was conducted through Review Manager (RevMan), version 5.3, and R software. We found that healthy volunteers with CYP2C9*2 or *3 carriers had higher area under the curve (AUC_0-∞) of losartan (mean difference (MD) 0.17 μg·h/mL; 95% confidence intervals (CI): 0.04, 0.29) and lower AUC_0-∞ of E-3174 (MD −0.35 μg·h/mL; 95% CI: −0.62, −0.08) than those with CYP2C9*1/*1. Subjects with CYP2C9*2 or *3 carriers showed lower maximum concentration (C_max) of E-3174 than those with CYP2C9*1/*1 (MD −0.13 μg/mL; 95% CI: −0.17, −0.09). For half-life, subjects with CYP2C9*2 or *3 carriers had longer half-lives of losartan and E-3174 than those with CYP2C9*1/*1 (MD 0.47 h; 95% CI: 0.32, 0.61 and MD 0.68 h; 95% CI: 0.44, 0.92, respectively). This meta-analysis suggests that the pharmacokinetics of losartan and E-3174 are associated with the CYP2C9 polymorphisms

Association between menopausal hormone therapy and risk of neurodegenerative diseases: Implications for precision hormone therapy

INTRODUCTION

The impact of menopausal hormone therapy (HT) on age-associated Alzheimer's and neurodegenerative diseases (NDDs) remains unresolved. To determine the effect of HT, formulation, type, and duration on risk of NDDs, a retrospective analysis was performed using a 10-year Humana claims dataset.

METHODS

Study population included women aged 45 years or older with or without claim records of HT medications. Patients diagnosed with NDDs including Alzheimer's disease (AD), Parkinson's disease (PD), dementia, multiple sclerosis (MS), and amyotrophic lateral sclerosis (ALS) were identified. Relative risk (RR) ratios and 95% confidence intervals (CI) for combined NDDs, or AD, PD, dementia, MS, and ALS were determined. Cumulative hazard ratios were determined to investigate the association between HT and NDDs at different age groups.

RESULTS

In 379,352 women with or without claim records of HT, use of HT was associated with significantly reduced risk for combined NDDs (RR 0.42, 95% CI 0.40-0.43, P < 0.001). Average follow-up time was 5.1 [2.3] years. Formulations containing natural steroids 17β-estradiol and/or progesterone were associated with greater reduction in NDD risk. Oral- HT users showed significantly reduced RRs (0.42, 0.41-0.44, P < 0.001) for combined NDDs compared to non-HT users. The RRs for transdermal-HT users were significantly decreased for all-cause dementia (0.73, 0.60-0.88, P = 0.001) and MS (0.55, 0.36-0.84, P = 0.005). Greatest reduction in risk of NDD, AD, and dementia emerged in patients aged 65 years or older. Further, the protective effect of long-term therapy (>1 year) on combined NDDs, AD, PD, and dementia was greater compared to short-term therapy (≤1 year).

DISCUSSION

HT was associated with reduced risk of all NDDs including AD and dementia, with greater duration of therapy and natural steroid formulations associated with greater efficacy. These findings advance precision HT to prevent NDDs including AD.

Han Chinese specific cytochrome P450 polymorphisms and their impact on the metabolism of anti-hypertensive drugs with adrenoreceptor blocking properties

Introduction: Cytochrome P450 (CYP) is a monooxygenase superfamily mediating the elimination of anti-hypertensive drugs. Polymorphisms of CYP would lead to differential drug efficacy. Building relationships between genotype and phenotype will benefit individual medical treatment of hypertension.Areas covered: The review systematically summarizes the polymorphisms of four CYPs (CYP2C9, CYP2C19, CYP2D6, and CYP3A4) concentrated distributed in the Han Chinese population. Moreover, the activity of variants on metabolizing anti-hypertensive drugs are reviewed, especially drugs with adrenoceptor blocking properties, as well as their clinical relevancies.Expert opinion: The polymorphisms of CYP can cause stratification in drug exposure of antihypertensive drugs. Although the clinical relevance has been built partially, the translational medicine still lacks reliable data support. Furthermore, the studies have demonstrated that even the same CYP variant will exhibit different catalytic capability for different drugs, which is another obstacle to hinder its application. With the deepening of multiomics research and structural biology, nucleotide polymorphisms can be combined with transcriptome, proteome, metabolome and molecular structure analyses to study the susceptibility to hypertension and drug efficacy. A complete data chain would be further estabolished by combining studies of pharmacokinetics-pharmacodynamics, which can effectively promote the precise application of anti-hypertensive drugs.

Identification of key pseudogenes in nasopharyngeal carcinoma based on RNA-Seq analysis

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a malignant head and neck tumor, and more than 70% of new cases are in East and Southeast Asia. However, association between NPC and pseudogenes playing important roles in genesis of multiple tumor types is still not clear and needs to be investigated.

METHODS

Using RNA-Sequencing (RNA-seq) technology, we analyzed pseudogene expression in 13 primary NPC and 6 recurrent NPC samples as well as their paracancerous counterparts. Quantitative PCR was used to validate the differentially expressed pseudogenes.

RESULTS

We found 251 differentially expressed pseudogenes including 73 up-regulated and 178 down-regulated ones between primary NPC and paracancerous tissues. Enrichment analysis of gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway were conducted to filter out the key pseudogenes. We reported that pseudogenes from cytochrome P450 (CYP) family, such as CYP2F2P, CYP2G1P, CYP4F24P, CYP2B7P and CYP2G2P were significantly down-regulated in NPC compared to paracancerous tissues, while IGHV1OR15-2, IGHV3-11, FCGR1CP and IGHV3-69-1 belonging to Fc gamma receptors were significantly up-regulated. CYP2B7P, CYP2F2P and CYP4F26P were enriched in arachidonic acid metabolism pathway. The qRT-PCR analysis validated the lower expression of pseudogenes CYP2F2P and CYP2B7P in NPC tissues and cell lines compared to paracancerous tissues and normal human nasopharyngeal epithelial cell line. CYP2B7P overexpression weakened migratory and invasive capacity of NPC cell line. Moreover, the expression pattern of those pseudogenes in recurrent NPC tissues was different from the primary NPC.

CONCLUSION

This study suggested the role of pseudogenes in tumorigenesis and progression, potentially functioning as therapeutic targets to NPC.

Comparison of Canine and Human Physiological Factors: Understanding Interspecies Differences that Impact Drug Pharmacokinetics

This review is a summary of factors affecting the drug pharmacokinetics (PK) of dogs versus humans. Identifying these interspecies differences can facilitate canine-human PK extrapolations while providing mechanistic insights into species-specific drug in vivo behavior. Such a cross-cutting perspective can be particularly useful when developing therapeutics targeting diseases shared between the two species such as cancer, diabetes, cognitive dysfunction, and inflammatory bowel disease. Furthermore, recognizing these differences also supports a reverse PK extrapolations from humans to dogs. To appreciate the canine-human differences that can affect drug absorption, distribution, metabolism, and elimination, this review provides a comparison of the physiology, drug transporter/enzyme location, abundance, activity, and specificity between dogs and humans. Supplemental material provides an in-depth discussion of certain topics, offering additional critical points to consider. Based upon an assessment of available state-of-the-art information, data gaps were identified. The hope is that this manuscript will encourage the research needed to support an understanding of similarities and differences in human versus canine drug PK.

A Novel CYP2C-Haplotype Associated With Ultrarapid Metabolism of Escitalopram

Escitalopram is one of the most commonly used antidepressant drugs but exhibits a substantial interindividual variation in clinical response. A key factor underlying response differences is the polymorphic nature of the CYP2C19 gene encoding the major enzyme responsible for escitalopram metabolism. Although pre-emptive CYP2C19 genotyping may improve escitalopram treatment outcome by dose individualization, much of the interindividual variability cannot be assigned to the currently known CYP2C19 gene variants. The aim of the present study was to search for novel CYP2C-haplotypes for better genetic prediction of escitalopram metabolism. First, the CYP2C18/CYP2C19 locus was sequenced from gDNA obtained from 24 patients previously genotyped as CYP2C19*1/*1 showing consistently low serum concentrations of escitalopram (< 25 nM/10 mg). Three new haplotypes of the CYP2C locus (CYP2C:TG, CYP2C:TA, and CYP2C:CG) were here identified, and their functional roles were evaluated using gDNA from 875 previously genotyped escitalopram-treated patients. The CYP2C:CG and CYP2C:TA haplotypes had no significant impact on escitalopram concentration. Based on the estimated effects of the novel CYP2C-haplotypes on escitalopram exposure, the predicted serum concentrations of escitalopram in homozygous CYP2C:TG and CYP2C19*17 carriers were 24.8% and 17.3% lower compared with the baseline (CYP2C:CG and CYP2C:TA), respectively. In conclusion, a novel CYP2C-haplotype defined by rs2860840T and rs11188059G associated with ultrarapid metabolism of escitalopram was identified. Further studies should clarify the genetic basis for the enhanced escitalopram metabolism and the impact of the CYP2C:TG haplotype on the metabolism of other CYP2C19 substrates like omeprazole, voriconazole, and clopidogrel.

Design, Synthesis and Binding Affinity Evaluation of Cytochrome P450 1B1 Targeted Chelators

BACKGROUND

Cytochrome P450 1B1 (CYP1B1) is specifically expressed in a variety of tumors which makes it a promise imaging target of tumor.

OBJECTIVE

We aimed to design and synthesize CYP1B1 targeted chelators for the potential application in positron emission tomography (PET) imaging of tumor.

METHODS

1,4,7-triazacyclononane-1,4-diiacetic acid (NODA) was connected to the CYP1B1 selective inhibitor we developed before through polyethylene glycol (PEG) linkers with different lengths. The inhibitory activities of chelators 6a-c against CYP1 family were evaluated by 7-ethoxyresorufin o-deethylation (EROD) assay. The manual docking between the chelators and the CYP1B1 are conducted subsequently. To determine the binding affinities of 6a-c to CYP1B1 in cells, we further performed a competition study at the cell level.

RESULTS

Among three chelators, 6a with the shortest linker showed the best inhibitory activity against CYP1B1. In the following molecular simulation study, protein-inhibitor complex of 6a showed the nearest F-heme distance which is consistent with the results of enzymatic assay. Finally, the cell based competitive assay proved the binding affinity of 6a-c to CYP1B1 enzyme.

CONCLUSION

We designed and synthesized a series of chelators which can bind to CYP1B1 enzyme in cancer cells.To our knowledge, this work is the first attempt to construct CYP1B1 targeted chelators for radiolabeling and we hope it will prompt the application of CYP1B1 imaging in tumor detection.

Drug-Metabolizing Cytochrome P450 Enzymes Have Multifarious Influences on Treatment Outcomes

Drug metabolism is a critical process for the removal of unwanted substances from the body. In humans, approximately 80% of oxidative metabolism and almost 50% of the overall elimination of commonly used drugs can be attributed to one or more of various cytochrome P450 (CYP) enzymes from CYP families 1-3. In addition to the basic metabolic effects for elimination, CYP enzymes in vivo are capable of affecting the treatment outcomes in many cases. Drug-metabolizing CYP enzymes are mainly expressed in the liver and intestine, the two principal drug oxidation and elimination organs, where they can significantly influence the drug action, safety, and bioavailability by mediating phase I metabolism and first-pass metabolism. Furthermore, CYP-mediated local drug metabolism in the sites of action may also have the potential to impact drug response, according to the literature in recent years. This article underlines the ability of CYP enzymes to influence treatment outcomes by discussing CYP-mediated diversified drug metabolism in primary metabolic sites (liver and intestine) and typical action sites (brain and tumors) according to their expression levels and metabolic activity. Moreover, intrinsic and extrinsic factors of personal differential CYP phenotypes that contribute to interindividual variation of treatment outcomes are also reviewed to introduce the multifarious pivotal role of CYP-mediated metabolism and clearance in drug therapy.

Evaluation of Cinnamon (Cinnamomum Verum) Effects on Liver CYP450 2D1 Activity and Hepatic Clearance in Diabetic Rats

Objectives: The present study assessed the effects of cinnamon on the activity of the liver CYP2D1 enzyme and hepatic clearance in the rat model of type 1 and 2 diabetes mellitus. Methods: Male Wistar rats were randomly categorized into 8 groups. Fourteen days after induction of diabetes type 1 and 2, type 1 groups received cinnamon and insulin plus cinnamon and type 2 groups received cinnamon and metformin plus cinnamon daily for 14 days. On day 28, rats were subjected to liver perfusion by buffer containing dextromethorphan as the CYP2D1 enzyme activity probe. Perfused samples were analyzed by high-performance liquid chromatography (HPLC) with fluorescence (FL) detection to evaluate the CYP2D1 activity and hepatic clearance. Results: In the control group, enzyme activity and hepatic clearance changed from 0.0081 ± 0.00009 and 6.09 ± 0.2 mL/min to 0.0059 ± 0.0001 and 3.71 ± 0.07 mL/min in the untreated type 1 diabetic rats and to 0.0006 ± 0.0001 and 5.19 ± 0.02 mL/min in untreated type 2 ones. These pharmacokinetic (PK) parameters changed to 0.0069 ± 0.0005 and 6.27 ± 0.06 mL/min in treated type 1 and 0.0115 ± 0.0003 and 5.79 ± 0.11 mL/min in the treated type 2 rats with only cinnamon administration. Treatment with cinnamon plus insulin or metformin modulated these PK parameters to 0.0039 ± 0.00006 and 4.88 ± 0.13 mL/min in type 1 and 0.0092 ± 0.0005 and 6.13 ± 0.01 mL/min in type 2 diabetic rats. Conclusions: Cinnamon can act as an effective complementary medicine in order to normalize the metabolism and clearance processes in diabetes mellitus.

Investigating the CYP2B6 rs3745274 and rs3211371 polymorphisms in Methadone-Responder and Non-Responder Addicts in Iran

Background

Methadone therapy is a major protocol in opioid addiction cases in many health care systems. Population-based studies have shown that in addicted people, the genetic profile affects their response to methadone therapy. Therefore, this study designed to examine the frequency of two SNPs of the CYP2B6 gene (rs3745274 and rs3211371) in addicted cases in two methadone-responders and methadone non-responders groups.

Methods

A total of 199 opioid-addicted individuals and 117 unaffected control subjects were genotyped for rs3745274 and rs3211371 polymorphisms of the CYP2B6 gene using the tetra-primer amplification refractory mutation system-polymerase chain reaction.

Results

Results of this study revealed the significant association of rs3745274 GG (p < 0.001; OR = 0.027; 95% CI = 0.14-0.49) and GT (p < 0.001; OR = 4.04; 95% CI = 2.26-7.21) genotypes with the risk of addiction in methadone-responders. Also, a significant association between rs3745274 GG (p < 0.001; OR = 0.28; 95% CI = 0.15-0.51) and GT (p < 0.001; OR = 5.1; 95% CI = 2.8-5.28) genotypes and addiction relapse was found in methadone non-responders.

Conclusion

Based on our findings, we can conclude that rs3745274 variant of CYP2B6 gene could serve as a potential biomarker, to evaluate the prognosis of addicted people fate under treatment with methadone.

Effect of CYP2C9 genetic polymorphism and breviscapine on losartan pharmacokinetics in healthy subjects

1. Breviscapine was an active ingredient of flavonoid glycosides. Our present study was conducted to evaluate the impact of breviscapine on the pharmacokinetics of losartan and its active metabolite E-3174, and that relationship with the gene polymorphism of CYP2C9 in healthy Chinese volunteers, to provide a basis for clinical rational drug use.2. The genotypes of 217 healthy Chinese subjects were determined using PCR-RFLP. Twelve healthy subjects were selected and were known CYP2C9 genotypes (six CYP2C9*1/*3 and six CYP2C9*1/*1) in a two-phase randomised crossover design study. These subjects were given daily doses of 120 mg (40 mg, three times a day) of breviscapine or a placebo for 14 days, followed by 50 mg losartan on day 15.3. Compared with individuals carrying the CYP2C9*1/*1 genotype, the CYP2C9*1/*3 genotype showed an increase in the AUC_(0-36) (833.6 ± 379.8 ng h ml^-1 vs. 526.1 ± 140.1 ng h ml^-1, p < 0.05) and a decrease in the MR (the metabolic ratio of losartan, AUC_E-3174/AUC_losartan) (2.67 ± 1.40 vs. 4.56 ± 0.83, p < 0.05) of losartan during the placebo treatment phase. Individuals with genotype CYP2C9*1/*3 showed a significant increase in AUC_(0-36) (2335 ± 851.8 ng h ml^-1 vs. 1927 ± 949.5 ng h ml^-1, p < 0.05) and AUC_(0-∞) (2363 ± 875.6 ng h ml^-1 vs. 1966 ± 966.1 ng h ml^-1, p < 0.05) of E-3174 after breviscapine treatment compared to the placebo group.4. In healthy subjects, breviscapine had no significant effect on the pharmacokinetics of losartan. The activity of CYP2C9 enzyme to losartan metabolism was more significant in subjects with CYP2C9*1/*3 than those with CYP2C9*1/*1 genotype.

Anatomical distribution and expression of CYP in humans: Neuropharmacological implications

The cytochrome P450 (CYP450) superfamily is responsible for the metabolism of most xenobiotics and pharmacological treatments generally used in clinical settings. Genetic factors as well as environmental determinants acting through fine epigenetic mechanisms modulate the expression of CYP over the lifespan (fetal vs. infancy vs. adult phases) and in diverse organs. In addition, pathological processes might alter the expression of CYP. In this selective review, we sought to summarize the evidence on the expression of CYP focusing on three specific aspects: (a) the anatomical distribution of the expression in body districts relevant in terms of drug pharmacokinetics (liver, gut, and kidney) and pharmacodynamics, focusing for the latter on the brain, since this is the target organ of psychopharmacological agents; (b) the patterns of expression during developmental phases; and (c) the expression of CYP450 enzymes during pathological processes such as cancer. We showed that CYP isoforms show distinct patterns of expression depending on the body district and the specific developmental phases. Of particular relevance for neuropsychopharmacology is the complex regulatory mechanisms that significantly modulate the complexity of the pharmacokinetic regulation, including the concentration of specific CYP isoforms in distinct areas of the brain, where they could greatly affect local substrate and metabolite concentrations of drugs.

DNA methylation determines the regulation of pregnane X receptor on CYP3A4 expression

The expression and activity of CYP3A4 vary among individuals. With the development of epigenetics, it is now possible to elucidate interindividual differences in drug-metabolizing enzymes. Here, we aimed to explore the potential relationship between DNA methylation and CYP3A4 expression. We analyzed the effect of a DNA methylation inhibitor, 5-aza-2-deoxycytidine, on pregnane X receptor (PXR) and CYP3A4 expression in HepG2 cells. In addition, pCpGL-CYP3A4-promoter and pCpGL-CYP3A4-enhancer plus promoter plasmids were constructed, methylated, and transfected. We found that treatment with 5-aza-2-deoxycytidine significantly increased the expression of PXR and CYP3A4 in a concentration- and time-dependent manner. In addition, CYP3A4 expression was significantly enhanced by overexpressing PXR via transfection of pSG5-PXR plasmids. Methylation of CYP3A4 enhancer inhibited CYP3A4 transcriptional activity mediated through PXR and inhibited the binding of PXR and CYP3A4 promoter. We also observed that when the promoter and enhancer of CYP3A4 were methylated, CYP3A4 expression did not increase after treatment with rifampicin. In conclusion, the investigation demonstrates that DNA methylation of CYP3A4 enhancer significantly inhibits CYP3A4 expression, mediated through PXR, which is not influenced by rifampicin.

Modulation of PARP activity by Monomethylarsonous (MMA+3) acid and uranium in mouse thymus

Arsenic exposure is well established to impair the function of zinc finger proteins, including PARP-1. Previous studies from our lab show that early developing T cells in the thymus are very sensitive to arsenite (As+3)-induced genotoxicity mediated through PARP-1 inhibition. Additionally, it has been shown that uranium (in the form of uranyl acetate, UA) also suppresses PARP-1 activity in HEK cells. However, very little is known about whether the As+3 metabolite, monomethylarsonous acid (MMA+3), also inhibits PARP-1 activity and if this is modified by combined exposures with other metals, such as uranium. In the present study, we found that MMA+3 significantly suppressed PARP-1 function, whereas UA at high concentrations significantly increased PARP-1 activity. To evaluate whether the effects on PARP-1 activity were mediated through oxidative stress, we measured the induction of hemoxygenase-1 (Hmox-1) expression by qPCR. MMA+3, but not UA, significantly induced oxidative stress; however, the inhibition of PARP-1 produced by MMA+3 was not reversed by the addition of the antioxidant, Tempol. Further evaluation revealed minimal interactive effects of MMA+3 and UA on PARP-1 function. Collectively, our results show that contrary to As+3, the suppressive effects of MMA+3 on PARP-1 were not substantially driven by oxidative stress. in mouse thymus cells. Results for this study provide important insights into the effects of MMA+3 and uranium exposures on PARP-1 function, which is essential for future studies focused on understanding the effects of complex environmentally relevant metal mixtures.

Neuropharmacological potentials of β-carboline alkaloids for neuropsychiatric disorders

Neuropsychiatric disorders are diseases of the central nervous system (CNS) which are characterised by complex pathomechanisms that including homeostatic failure, malfunction, atrophy, pathology remodelling and reactivity anomaly of the neuronal system where treatment options remain challenging. β-Carboline (βC) alkaloids are scaffolds of structurally diverse tricyclic pyrido[3,4-b]indole alkaloid with vast occurrence in nature. Their unique structural features which favour interactions with enzymes and protein receptor targets account for their potent neuropharmacological properties. However, our current understanding of their biological mechanisms for these beneficial effects, especially for neuropsychiatric disorders is sparse. Therefore, we present a comprehensive review of the scientific progress in the last two decades on the prospective pharmacology and physiology of the βC alkaloids in the treatment of some neuropsychiatric conditions such as depression, anxiety, Alzheimer's disease, Parkinson's disease, brain tumour, essential tremor, epilepsy and seizure, licking behaviour, dystonia, agnosia, spasm, positive ingestive response as demonstrated in non-clinical models. The current evidence supports that βC alkaloids offer potential therapeutic agents against most of these disorders and amenable for further drug design.

How Can Drug Metabolism and Transporter Genetics Inform Psychotropic Prescribing?

Many genetic variants in drug metabolizing enzymes and transporters have been shown to be relevant for treating psychiatric disorders. Associations are strong enough to feature on drug labels and for prescribing guidelines based on such data. A range of commercial tests are available; however, there is variability in included genetic variants, methodology, and interpretation. We herein provide relevant background for understanding clinical associations with specific variants, other factors that are relevant to consider when interpreting such data (such as age, gender, drug-drug interactions), and summarize the data relevant to clinical utility of pharmacogenetic testing in psychiatry and the available prescribing guidelines. We also highlight areas for future research focus in this field.

Large-scale Generation of Functional and Transplantable Hepatocytes and Cholangiocytes from Human Endoderm Stem Cells

The ever-increasing therapeutic and pharmaceutical demand for liver cells calls for systems that enable mass production of hepatic cells. Here we describe a large-scale suspension system that uses human endoderm stem cells (hEnSCs) as precursors to generate functional and transplantable hepatocytes (E-heps) or cholangiocytes (E-chos). hEnSC-derived hepatic populations are characterized by single-cell transcriptomic analyses and compared with hESC-derived counterparts, in-vitro-maintained or -expanded primary hepatocytes and adult cells, which reveals that hepatic differentiation of hEnSCs recapitulates in vivo development and that the heterogeneities of the resultant populations can be manipulated by regulating the EGF and MAPK signaling pathways. Functional assessments demonstrate that E-heps and E-chos possess properties comparable with adult counterparts and that, when transplanted intraperitoneally, encapsulated E-heps were able to rescue rats with acute liver failure. Our study lays the foundation for cell-based therapeutic agents and in vitro applications for liver diseases.

Polymorphic variants of drug-metabolizing enzymes alter the risk and survival of oral cancer patients

The present study investigated the prevalence of CYP2D6*4, CYP3A5*3 and SULT1A1*2, using PCR-RFLP, in normal and oral cancer (OC) patients that were stratified by OC subtype and gender. The risk of cancer, 5-year cumulative survival and hazard's ratio (HR) with respect to risk factors and clinical factors were estimated using Fisher's exact test, Kaplan-Meier analysis, and Cox proportional hazards models. CYP2D6*4 'GA' lowered the risk of buccal mucosa cancer (BMC) in males (OR = 0.37), whereas, 'G' allele of CYP3A5*3 increased risk of tongue cancer (TC) (OR = 1.67). SULT1A1*2 'GA' increased the risk of TC (OR = 2.36) and BMC (OR = 3.25) in females. The 5-year survival of the patients depended on factors like age, lymphovascular spread (LVS), perinodal spread (PNS), recurrence, tobacco, and alcohol. CYP3A5*3 'AG' and 'GG' had decreased the hazard ratio (HR) for BMC females when inflammatory infiltrate alone or along with other covariates, LVS, PNI, PNS, metastasis, recurrence, and relapse was adjusted. Similarly, CYP3A5*3 'AG' decreased the risk of death (HR = 0.05) when the grade was adjusted. SULT1A1*2 'GA' had decreased HR for TC males (HR = 0.08) after adjusting for inflammatory infiltrate, LVS, perineural invasion (PNI), PNS, metastasis, recurrence, and relapse. Further, our bioinformatics study revealed the presence of a CpG island within the CYP2D6 and a CTCF binding site upstream of CYP2D6. Interestingly, three CpG islands and two CTCF binding sites were also identified near the SULT1A1. In conclusion, the SNPs altered risk and survival of BMC and TC differentially in a gender specified manner, that varied with clinical and risk factors.

Reduction in Tamoxifen Metabolites Endoxifen and N-desmethyltamoxifen With Chronic Administration of Low Dose Cannabidiol: A CYP3A4 and CYP2D6 Drug Interaction

BACKGROUND

Cannabidiol (CBD) serves as a promising medicine, with few known adverse effects apart from the potential of drug interactions with the cytochrome P450 system. It has been hypothesized drug interactions may occur with chemotherapeutic agents, but no supporting evidence has been published to date.

CASE

A 58-year-old female with a history of bilateral breast carcinoma in remission, was treated with tamoxifen for breast cancer prevention for over 6 years. CBD was instituted to treat persistent postsurgical pain, inadequately managed by alternate analgesics. It was postulated that CBD may diminish tamoxifen metabolism by CYP3A4 and 2D6 to form active metabolite endoxifen, which exerts the anticancer benefits. Endoxifen, tamoxifen, N-desmetyltamoxifen and 4-hydroxytamoxifen levels were collected while the patient chronically received CBD 40 mg/day, and after a 60-day washout. Upon discontinuation of CBD 40 mg/day, it was observed that endoxifen levels increased by 18.75% and N-desmethyltamoxifen by 9.24%, while 4-hydroxytamoxifen remained unchanged.

CONCLUSION

CBD at a low dose of 40 mg/day resulted in the potential inhibition of CYP3A4 and/or CYP2D6. Patients receiving CBD and interacting chemotherapeutic drugs, such as tamoxifen, require monitoring to identify possible subtherapeutic response to treatment. Further pharmacokinetic studies are required to ascertain the dynamics of this drug interaction.

Salidroside - Can it be a Multifunctional Drug?

BACKGROUND

Salidroside is a glucoside of tyrosol found mostly in the roots of Rhodiola spp. It exhibits diverse biological and pharmacological properties. In the last decade, enormous research is conducted to explore the medicinal properties of salidroside; this research reported many activities like anti-cancer, anti-oxidant, anti-aging, anti-diabetic, anti-depressant, anti-hyperlipidemic, anti-inflammatory, immunomodulatory, etc. Objective: Despite its multiple pharmacological effects, a comprehensive review detailing its metabolism and therapeutic activities is still missing. This review aims to provide an overview of the metabolism of salidroside, its role in alleviating different metabolic disorders, diseases and its molecular interaction with the target molecules in different conditions. This review mostly concentrates on the metabolism, biological activities and molecular pathways related to various pharmacological activities of salidroside.

CONCLUSION

Salidroside is produced by a three-step pathway in the plants with tyrosol as an intermediate molecule. The molecule is biotransformed into many metabolites through phase I and II pathways. These metabolites, together with a certain amount of salidroside may be responsible for various pharmacological functions. The salidroside based inhibition of PI3k/AKT, JAK/ STAT, and MEK/ERK pathways and activation of apoptosis and autophagy are the major reasons for its anti-cancer activity. AMPK pathway modulation plays a significant role in its anti-diabetic activity. The neuroprotective activity was linked with decreased oxidative stress and increased antioxidant enzymes, Nrf2/HO-1 pathways, decreased inflammation through suppression of NF-κB pathway and PI3K/AKT pathways. These scientific findings will pave the way to clinically translate the use of salidroside as a multi-functional drug for various diseases and disorders in the near future.

Predicting Metabolism-Related Drug-Drug Interactions Using a Microphysiological Multitissue System

Drug-drug interactions (DDIs) occur when the pharmacological activity of one drug is altered by a second drug. As multimorbidity and polypharmacotherapy are becoming more common due to the increasing age of the population, the risk of DDIs is massively increasing. Therefore, in vitro testing methods are needed to capture such multiorgan events. Here, a scalable, gravity-driven microfluidic system featuring 3D microtissues (MTs) that represent different organs for the prediction of drug-drug interactions is used. Human liver microtissues (hLiMTs) are combined with tumor microtissues (TuMTs) and treated with drug combinations that are known to cause DDIs in vivo. The testing system is able to capture and quantify DDIs upon co-administration of the anticancer prodrugs cyclophosphamide or ifosfamide with the antiretroviral drug ritonavir. Dosage of ritonavir inhibits hepatic metabolization of the two prodrugs to different extents and decreases their efficacy in acting on TuMTs. The flexible MT compartment design of the system, the use of polystyrene as chip material, and the assembly of several chips in stackable plates offer the potential to significantly advance preclinical substance testing. The possibility of testing a broad variety of drug combinations to identify possible DDIs will improve the drug development process and increase patient safety.

Metabolic mechanism and anti-inflammation effects of sinomenine and its major metabolites N-demethylsinomenine and sinomenine-N-oxide

AIMS

Sinomenine (SIN) is clinically used as an anti-rheumatic drug. However, the metabolic and pharmacological mechanisms of SIN combined with its metabolites are unclear. This study aims to explore the cyclic metabolic mechanism of SIN, the anti-inflammation effects of SIN and its major metabolites (N-demethylsinomenine (DS) and sinomenine-N-oxide (SNO)), and the oxidation property of SNO.

MATERIALS AND METHODS

SIN was administrated to rats via gavage. Qishe pills (a SIN-containing drug) were orally administrated to humans. The bio-samples were collected to identify SIN's metabolites. Enzymatic and non-enzymatic incubations were used to reveal SIN's metabolic mechanism. Impacts of SIN, SNO and DS on the inflammation-related cytokine's levels and nuclear translocation of NF-κB were evaluated in LPS-induced Raw264.7 cells. ROS induced by SNO (10 μM) was also assessed.

KEY FINDINGS

CYP3A4 and ROS predominantly mediated the formation of SNO, and CYP3A4 and CYP2C19 primarily mediated the formation of DS. Noteworthily, SNO underwent N-oxide reduction both enzymatically, by xanthine oxidase (XOD), and non-enzymatically, by ferrous ion and heme moiety. The levels of IL-6 and TNF-α and nuclear translocation of NF-κB were ameliorated after pretreatment of SIN in LPS-induced Raw264.7 cells, while limited attenuations were observed after pretreatment of DS (SNO) even at 200 μM. In contrast, SNO induced ROS production.

SIGNIFICANCE

This study elucidated that SIN underwent both enzymatic and non-enzymatic cyclic metabolism and worked as the predominant anti-inflammation compound, while SNO induced ROS production, suggesting more studies of SIN combined with SNO and DS are necessary in case of DDI and potential toxicities.

Phase I trial of the MET inhibitor tepotinib in Japanese patients with solid tumors

OBJECTIVES

Tepotinib (MSC2156119J) is an oral, potent and highly selective small molecule mesenchymal-epithelial transition factor (MET) inhibitor for which the recommended Phase II dose of 500 mg once daily has been defined, based on the first-in-man trial conducted in the USA and Europe. We carried out a multicenter Phase I trial with a classic `3 + 3' design to determine the recommended Phase II dose in Japanese patients with solid tumors (NCT01832506).

METHODS

Patients aged ≥20 years with advanced solid tumors (refractory to standard therapy or for whom no effective standard therapy was available) received tepotinib at 215, 300 or 500 mg once daily in a 21-day cycle. Occurrence of dose-limiting toxicities during cycle 1 was used to determine the maximum tolerated dose. Efficacy, safety and pharmacokinetics were also evaluated to support the dose assessment.

RESULTS

Twelve patients were treated. Tepotinib was generally well tolerated with no observed dose-limiting toxicities; treatment-related adverse events were mainly grades 1-2. The tolerability profile of tepotinib was similar to that observed in non-Japanese populations. Pharmacokinetics in Japanese and Western patients was comparable. One patient with gastric cancer and one patient with urachal cancer had stable disease of ≥12 weeks in duration. The observed safety profile and pharmacokinetics are comparable with those in patients from the USA and Europe, and the recommended Phase II dose of tepotinib in Japanese patients was confirmed as 500 mg once daily.

CONCLUSIONS

These results, including initial signals of antitumor activity, support further development of tepotinib in Japanese patients with cancer.

Investigating the Role of Missense SNPs on ALDH 1A1 mediated pharmacokinetic resistance to cyclophosphamide

Cyclophosphamide (CP) is a well-known anti-cancer drug, which exerts its therapeutic effect by DNA cross-linking, both within and between DNA strands. Earlier, a single dose of CP was enough for an effective treatment however due to overexpression of ALDH 1A1 in cancer cells and consequent drug inactivation, the quality of treatment suffered a lot. Drug inactivation via Drug Metabolizing Enzyme (DME) like Aldehyde dehydrogenase 1A1 (ALDH 1A1) is one of the resistance mechanism which is least considered and somewhat overlooked. The current study focused on investigating the impact of missense SNPs on ALDH 1A1 mediated pharmacokinetic resistance to CP. To achieve this aim, we selected 14 missense SNPs from the large pool of SNPs database. The stability of the mutants corresponding to selected SNPs was then determined using web-based tools like I-Mutant, CUPSAT, Maestro-web, STRUM, Eris, SDM, DUET, I-Stable. The obtained results from the mentioned web tools were later validated by molecular dynamic simulations. Furthermore, to find out the optimal range in terms of geometrical parameters and binding affinity for a molecule to be a good substrate for ALDH 1A1, some well-reported substrates of ALDH1A1 were pooled from the literature. Subsequently, similar parameters were calculated for each aldophosphamide (Active metabolite of CP) - mutant complexes to determine if these parameters lie within the optimal range. Based on this analyses population which is most or least susceptible to resistance was suggested. Our results demonstrated that the population group corresponding to rs11554423 (Gly125Arg) and rs763363983 (Val460Leu) mutation may be least vulnerable to CP resistance. Whereas, the population corresponding to rs1049981 (Asn121Ser) and rs774967243 (Val295Leu) SNPs may be most vulnerable to CP resistance.

Drug-Induced Liver Injury After Liver Transplantation

Drug-induced liver injury (DILI) is an adverse reaction to many drugs in common use that in a liver transplantation (LT) recipient may cause graft dysfunction and may even lead to graft loss and the need for retransplantation. However, several potential clinical scenarios, such as graft rejection and infection, can confound the diagnosis of suspected DILI in the setting of LT. This makes causal assessment of a new liver injury more uncertain and has traditionally precluded collection of bona fide cases of DILI affecting LT patients in prospective DILI registries and cohorts. Although no studies have yet determined a greater susceptibility of the transplant patient to DILI, these patients nevertheless present certain risk factors that can theoretically increase the risk of DILI. These include the fact that these patients are polymedicated, use drugs that are potentially hepatotoxic, and can have coexisting hepatitis B or C viruses in addition to other factors found in nontransplant patients, such as genetic variants. Therefore, awareness is crucial of any potential hepatotoxic effect of drugs used in the LT recipient and their possible implication in any case of liver dysfunction. In the present article, we review the most common drugs used in LT recipients from a liver safety perspective and address the main pitfalls in attributing causality in this clinical setting. We also affirm the need for further research and collaboration in this somewhat neglected topic in the field of DILI.