Polymorphism of human cytochrome P450 enzymes and its clinical impact

Heterologous expression of high-activity cytochrome P450 in mammalian cells

The evaluation of Cytochrome P450 (CYP) enzymatic activity is essential to estimate drug pharmacokinetics. Numerous CYP allelic variants have been identified; the functional characterisation of these variants is required for their application in precision medicine. Results from heterologous expression systems using mammalian cells can be integrated in in vivo studies; however, other systems such as E. coli, bacteria, yeast, and baculoviruses are generally used owing to the difficulty in expressing high CYP levels in mammalian cells. Here, by optimising transfection and supplementing conditions, we developed a heterologous expression system using 293FT cells to evaluate the enzymatic activities of three CYP isoforms (CYP1A2, CYP2C9, and CYP3A4). Moreover, we established co-expression with cytochrome P450 oxidoreductase and cytochrome b₅. This expression system would be a potential complementary or beneficial alternative approach for the pharmacokinetic evaluation of clinically used and developing drugs in vitro.

Hepatocytic transcriptional signatures predict comparative drug interaction potential of rifamycin antibiotics

Current strategies to treat tuberculosis (TB) and co-morbidities involve multidrug combination therapies. Rifamycin antibiotics are a key component of TB therapy and a common source of drug–drug interactions (DDIs) due to induction of drug metabolizing enzymes (DMEs). Management of rifamycin DDIs are complex, particularly in patients with co-morbidities, and differences in DDI potential between rifamycin antibiotics are not well established. DME profiles induced in response to tuberculosis antibiotics (rifampin, rifabutin and rifapentine) were compared in primary human hepatocytes. We identified rifamycin induced DMEs, cytochrome P450 (CYP) 2C8/3A4/3A5, SULT2A, and UGT1A4/1A5 and predicted lower DDIs of rifapentine with 58 clinical drugs used to treat co-morbidities in TB patients. Transcriptional networks and upstream regulator analyses showed FOXA3, HNF4α, NR1I2, NR1I3, NR3C1 and RXRα as key transcriptional regulators of rifamycin induced DMEs. Our study findings are an important resource to design effective medication regimens to treat common co-conditions in TB patients.

Pharmacogenomics, concepts for the future of perioperative medicine and pain management: A review

Pharmacogenomics is the study of how genetic differences between individuals affect pharmacokinetics and pharmacodynamics. These differences are apparent to clinicians when taking into account the wide range of responses to medications given in clinical practice. A review of literature involving pharmacogenomics and pain management was performed. The implementation of preoperative pharmacogenomics will allow us to better care for our patients by delivering personalized, safer medicine. This review describes the current state of pharmacogenomics as it relates to many aspects of clinical practice and how clinicians can use these tools to improve patient outcomes.

The protective role of ginsenoside compound K in porcine oocyte meiotic maturation failed caused by benzo(a)pyrene during in vitro maturation

Benzo(a)pyrene (BaP) is a pollutant and carcinogen derived from air pollution. It causes serious damage to reproductive system, especially ovary. Ginseng is always used in food and traditional medicine as a nutraceuticals or herbal medicine. Ginsenoside compound K (CK) is a major bioactive ingredient of ginseng, that shows very specific anti-apoptosis, anti-oxidant, and anti-inflammatory activities and thus, it protects cells from damage. The aim of this study was to investigate the effects of CK on the BaP-induced inhibition of the in vitro maturation of porcine oocytes and their subsequent embryonic development capacity. We found that supplementation with 10 μg mL^-1 CK during in vitro maturation significantly increased maturation rate (P < 0.05) and the expression level of related genes after damage induced by 40 μM BaP treatment. In addition, reactive oxygen species (ROS) levels significantly decreased and ATP content and mitochondrial membrane potential (MMP) increased after CK supplementation (P < 0.05). The competence for embryonic development was improved by the induction of pluripotency gene expression and the inhibition of apoptosis after CK supplementation of BaP-treated oocytes. Supplementation with 10 μg mL^-1 CK improved porcine oocyte maturation and subsequent embryonic development of parthenogenetic activation (33.01 vs. 20.92, P < 0.05) and in vitro fertilization (24.01 vs. 16.52, P < 0.05) by increasing antioxidant activity and improving mitochondrial function after BaP-induced damage.

The effect of apatinib on pharmacokinetic profile of buspirone both in vivo and in vitro

OBJECTIVE

In this study, we aimed to investigate the potential interaction of apatinib and buspirone and underlying mechanism.

METHODS

UPLC-MS/MS assay was applied to determine the concentrations of buspirone and its main metabolites (1-PP and 6-OH buspirone) after incubated with liver microsomes. Moreover, the connection of in vitro and in vivo was further determined. Sprague Dawley rats were randomly divided into two groups: group A (20 mg/kg buspirone) and group B (buspirone vs 40 mg/kg apatinib). Tail vein blood was collected and subjected to the UPLC-MS/MS detection.

KEY FINDINGS

Apatinib inhibited the generations of 1-PP and 6-OH buspirone dose-dependently with IC₅₀ of 1.76 and 2.23 μm in RLMs, and 1.51 and 1.48 μm in HLMs, respectively. There was a mixed mechanism underlying such an inhibition effect. In rat, AUC_{(0- t )} , AUC_(0-∞) , T_max and C_max of buspirone and 6-OH buspirone increased significantly while co-administering with apatinib, but V_z/F and CL_z/F decreased obviously while comparing group A with group B .

CONCLUSIONS

Apatinib suppresses the CYP450 based metabolism of buspirone in a mixed mechanism and boosted the blood exposure of prototype drug and 6-OH buspirone dramatically. Therefore, extra caution should be taken when combining apatinib with buspirone in clinic.

Nursing Personnel in the Era of Personalized Healthcare in Clinical Practice

Personalized, stratified, or precision medicine (PM) introduces a new era in healthcare that tries to identify and predict optimum treatment outcomes for a patient or a cohort. It also introduces new scientific terminologies regarding therapeutic approaches and the need of their adoption from healthcare providers. Till today, evidence-based practice (EBP) was focusing on population averages and their variances among cohorts for clinical values that are essential for optimizing healthcare outcome. It can be stated that EBP and PM are complementary approaches for a modern healthcare system. Healthcare providers through EBP often see the forest (population averages) but miss the trees (individual patients), whereas utilization of PM may not see the forest for the trees. Nursing personnel (NP) play an important role in modern healthcare since they are consulting, educating, and providing care to patients whose needs often needs to be individualized (personalized nursing care, PNC). Based on the clinical issues earlier addressed from clinical pharmacology, EBP, and now encompassed in PM, this review tries to describe the challenges that NP have to face in order to meet the requisites of the new era in healthcare. It presents the demands that should be met for upgrading the provided education and expertise of NP toward an updated role in a modern healthcare system.

Salidroside as a potential neuroprotective agent for ischemic stroke: a review of sources, pharmacokinetics, mechanism and safety

Salidroside (Sal) is a bioactive extract principally from traditional herbal medicine such as Rhodiola rosea L., which has been commonly used for hundreds of years in Asia countries. The excellent neuroprotective capacity of Sal has been illuminated in recent studies. This work focused on the source, pharmacokinetics, safety and anti-ischemic stroke (IS) effect of Sal, especially emphasizing its mechanism of action and BBB permeability. Extensive databases, including Pubmed, Web of science (WOS), Google Scholar and China National Knowledge Infrastructure (CNKI), were applied to obtain relevant online literatures. Sal exerts powerful therapeutic effects on IS in experimental models either in vitro or in vivo due to its neuroprotection, with significantly diminishing infarct size, preventing cerebral edema and improving neurological function. Also, the findings suggest the underlying mechanisms involve anti-oxidation, anti-inflammation and anti-apoptosis by regulating multiple signaling pathways and key molecules, such as NF-κB, TNF-α and PI3K/Akt pathway. In pharmacokinetics, although showing a rapid absorption and elimination, bioavailability of Sal is elevated under some non-physiological conditions. The component and its metabolite (tyrosol) are capable of distributing to brain tissue and the later keeps a higher level of concentration. Moreover, Sal scarcely has obvious toxicity or side effects in a variety of animal experiments and clinical trials, but combination of drugs and perinatal use of medicine should be taken more attentions. Finally, as an active ingredient, not only is Sal isolated from diverse plants with limited yield, but also large batches of the products can be harvested by biological and chemical synthesis. With higher efficacy and better safety profiles, Sal could sever as a promising neuroprotectant for preventing and treating IS. Nevertheless, further investigations are still required to explore the pharmacodynamic and pharmacokinetic properties of Sal in the treatment of IS.

Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)-Based Proteomics of Drug-Metabolizing Enzymes and Transporters

Liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based proteomics is a powerful tool for identifying and quantifying proteins in biological samples, outperforming conventional antibody-based methods in many aspects. LC-MS/MS-based proteomics studies have revealed the protein abundances of many drug-metabolizing enzymes and transporters (DMETs) in tissues relevant to drug metabolism and disposition. Previous studies have consistently demonstrated marked interindividual variability in DMET protein expression, suggesting that varied DMET function is an important contributing factor for interindividual variability in pharmacokinetics (PK) and pharmacodynamics (PD) of medications. Moreover, differential DMET expression profiles were observed across different species and in vitro models. Therefore, caution must be exercised when extrapolating animal and in vitro DMET proteomics findings to humans. In recent years, DMET proteomics has been increasingly utilized for the development of physiologically based pharmacokinetic models, and DMET proteins have also been proposed as biomarkers for prediction of the PK and PD of the corresponding substrate drugs. In sum, despite the existence of many challenges in the analytical technology and data analysis methods of LC-MS/MS-based proteomics, DMET proteomics holds great potential to advance our understanding of PK behavior at the individual level and to optimize treatment regimens via the DMET protein biomarker-guided precision pharmacotherapy.

Review of nutritional status, body composition, and effects of antineoplastic drug disposition

The overall survival for children with cancer in high income countries is excellent. However, there are many disparities that may negatively affect survival, which are particularly problematic in low income countries, such as nutritional status at diagnosis and throughout therapy. Nutritional status as well as concomitant foods, supplements, and medications may play a role in overall exposure and response to chemotherapy. Emerging science around the microbiome may also play a role and should be further explored as a contributor to disease progression and therapeutic response. This article highlights some of these issues and proposes additional areas of research relevant to nutritional status and pharmacology that are needed in pediatric oncology.

Altered hepatic cytochrome P450 expression in cats after chronic exposure to decabromodiphenyl ether (BDE-209)

The knowledge of cytochrome P450 (CYP) expression involved in chemical exposure are necessary in clinical applications for the medication and prediction of adverse effects. The aim of this study was to evaluate the mRNA expression of CYP1–CYP3 families in cats exposed to BDE-209 for one year. All selected CYP isoforms showed no significant difference in mRNA expressions between control and exposure groups, however, CYP3A12 and CYP3A131 revealed tend to be two times higher in the exposure group compared to control group. The present results indicate that the chronic exposure of BDE209 could not alter CYP expression in the liver of cats. This result considered caused by the deficiency of CYP2B subfamily which is major metabolism enzyme of polybrominated diphenyl ethers (PBDEs) in cat.

Clopidogrel response in ischemic stroke patients: Is polymorphism or gender more important? Results of the CRISP study

Clopidogrel (CLP) is a second generation thienopyridine drug commonly used in secondary prevention of ischemic stroke (IS). Its antiplatelet response maybe variable due to genetic and non-genetic factors. Adipokines may affect platelet aggregation through ADP mediated platelet signalling. However, the combined effect of CYP genetic variants and adipokines on antiplatelet response of clopidogrel is unclear. Patients of IS/Transient ischemic attack (TIAs) within 3 months were prospectively screened following clopidogrel treatment. Major exclusions were cardioembolic and non atherosclerotic strokes. Antiplatelet effect of clopidogrel along with adipokine (Leptin and adiponectin) levels and genotyping of CYP, P2Y12 gene were investigated. Rare genetic variants were confirmed by DNA sequencing. 204 patients with ischemic stroke/TIAs were screened and 163 were recruited. 85 (52.1%) patients were poor responders to clopidogrel. Antiplatelet response to clopidogrel was weaker in females [Median 8.0 (IQR: 3.0-14.0)] compared to males [Median 5.0 (IQR: 2.0-10.0)]. In female subgroup analysis, association was found among high leptin levels and PPI (+) usage in poor responders. None of the genetic variants (CYP2C19*2,*3,*4*, CYP2C9*3, CYP2B6 and P2Y12) were found to influence the antiplatelet effects (p > 0.05). On multivariable logistic regression, a poor clopidogrel response was associated with female gender (Adjusted OR 2.55, 95% CI: 1.05-6.18) and PPI usage (Adjusted OR 2.42, 95% CI: 1.09-5.34). Despite a high prevalence of clopidogrel resistance in the North Indian stroke patients, female gender rather than genetic polymorphisms of CYP and P2Y12 genes may influence its antiplatelet effect. Further research may ascertain the role of gender on clopidogrel response.

Emerging roles of metabolites of ω3 and ω6 essential fatty acids in the control of intestinal inflammation

The gastrointestinal tract is continuously exposed to the external environment, which contains numerous non-self antigens, including food materials and commensal micro-organisms. For the maintenance of mucosal homeostasis, the intestinal epithelial layer and mucosal immune system simultaneously provide the first line of defense against pathogens and are tightly regulated to prevent their induction of inflammatory responses to non-pathogenic antigens. Defects in mucosal homeostasis lead to the development of inflammatory and associated intestinal diseases, such as Crohn’s disease, ulcerative colitis, food allergy and colorectal cancer. The recent discovery of novel dietary ω3 and ω6 lipid-derived metabolites—such as resolvin, protectin, maresin, 17,18-epoxy-eicosatetraenoic acid and microbe-dependent 10-hydroxy-cis-12-octadecenoic acid—and their potent biologic effects on the regulation of inflammation have initiated a new era of nutritional immunology. In this review, we update our understanding of the role of lipid metabolites in intestinal inflammation.

Genetic variations in drug-metabolizing enzyme CYP2C9 among major ethnic groups of Pakistani population

The genetic polymorphism of cytochrome P450 (CYPs)drug-metabolizing enzymes are well studied in human populations for drug safety and efficacy. CYP2C9 is a highly polymorphic CYP enzyme that oxidizing the indigenous compounds and xenobiotics. The present study was pursued to evaluate the genetic variation across the CYP2C9 gene among major groups of the Pakistani population. The CYP2C9 genomic region holding important warfarin drug-metabolizing SNPs was sequenced from 159 individuals belong from five major ethnic groups of Pakistani population. The population genetic analyses of the high-quality sequences data was performed using Arlequin v3.5, DnaSP v6.12 and Network 5 resources. The data analyses unveiled that genetic variance among samples mainly arose from population-scale differentiation among these ethnic groups with global Fst of 0.78, P-value < 0.0001. The highest pairwise population genetic variation observed between Saraiki and Baloch groups based on different statistical tests. Whereas, uniform genetic composition across CYP2C9 loci was inferred among Punjabi, Pathan and Sindhi groups with minimal genetic differentiation. Several SNPs, including the previously reported warfarin associated variants, i.e. rs2860905, rs1799853 (CYP2C9*2) and rs72558189 (CYP2C9*14) were detected in these population groups with diverse allelic frequencies. Besides, a novel intronic SNP, i.e. not available in dbSNP and Ensemble databases, was identified for a Sindhi individual sample. This novel SNP predicted to influence the CYP2C9 alternative transcript splicing. The pharmacogeneticsassessment of the CYP2C9 genetic variations identified in current study may important to test against the warfarin efficacy for different ethnicity of Pakistani population.

MicroRNA-16 participates in the cell cycle alteration of HepG2 cells induced by MC-LR

Microcystin-LR (MC-LR) is a cyclic hepatotoxin produced by cyanobacteria in freshwater, and chronic MC-LR exposure could induce human hepatitis if consumed in drinking water. In recent years, many studies have indicated that microRNAs participate in the hepatotoxicity of MC-LR. The purpose of this study was to investigate the potential function of miR-16 in the hepatocellular toxicity and cell cycle alteration induced by MC-LR in human hepatocellular carcinoma (HepG2) cells after treatment with 10 μM MC-LR. The result of flow cytometry detection showed that a low concentration of MC-LR (10 μM) failed to induce apoptosis but promoted cell cycle G1/S transition in HepG2 cells. In addition, the expression of apoptosis-related genes was suppressed after MC-LR exposure. These results confirm that MC-LR exposure at a low dose can promote the proliferation of HepG2 cells. Furthermore, we also found that microRNA-16 (miR-16) expression was suppressed in HepG2 cells following MC-LR exposure. Hence, we overexpressed miR-16 in HepG2 cells and treated them with MC-LR, and the results showed that miR-16 overexpression induced an increase in the G0/G1 phase and a decrease in the S phase cell cycle populations in HepG2 cells, suggesting that miR-16 can inhibit the cell proliferation of HepG2 cells. In conclusion, our results suggest that miR-16 may play a vital role in the cell cycle alteration of HepG2 cells after MC-LR exposure.

Genetic Influence on Efficacy of Pharmacotherapy for Pediatric Attention-Deficit/Hyperactivity Disorder: Overview and Current Status of Research

Multiple stimulant and non-stimulant medications are approved for the treatment of attention-deficit/hyperactivity disorder (ADHD), one of the most prevalent childhood neurodevelopmental disorders. Choosing among the available agents and determining the most effective ADHD medication for a given child can be a time-consuming process due to the high inter-individual variability in treatment efficacy. As a result, there is growing interest in identifying predictors of ADHD medication response in children through the burgeoning field of pharmacogenomics. This article reviews childhood ADHD pharmacogenomics efficacy studies published during the last decade (2009-2019), which have largely focused on pharmacodynamic candidate gene investigations of methylphenidate and atomoxetine response, with a smaller number investigating pharmacokinetic candidate genes and genome-wide approaches. Findings from studies which have advanced the field of ADHD pharmacogenomics through investigation of meta-analytic approaches and gene-gene interactions are also overviewed. Despite recent progress, no one genetic variant or currently available pharmacogenomics test has demonstrated clinical utility in pinpointing the optimal ADHD medication for a given individual patient, highlighting the need for further investigation.

Oral Ciprofloxacin Pharmacokinetics in Healthy Mexican Volunteers and Other Populations: Is There Interethnic Variability?

BACKGROUND

There is evidence that the pharmacokinetics of certain drugs in Mexicans may differ with respect to other ethnic groups. On the other hand, there is controversy about the existence of interethnic variability in the pharmacokinetics of ciprofloxacin.

AIM OF THE STUDY

To study oral ciprofloxacin pharmacokinetics in Mexicans at various dose levels and make comparisons with other populations in order to gain insight on interethnic variability.

METHODS

Healthy Mexican volunteers received oral ciprofloxacin as 250 mg and 500 mg immediate-release tablets or a 1,000 mg extended-release formulation. Plasma concentration against time curves were constructed, and pharmacokinetic parameters were compared with those reported for other populations.

RESULTS

Ciprofloxacin pharmacokinetics in Mexicans was linear and no significant differences between males and females were detected. When several populations were compared, it appeared that bioavailability in Mexicans was similar to that of Caucasians, being lower than that of Asians. These variations were attenuated when data were normalized by body weight.

CONCLUSIONS

Ciprofloxacin pharmacokinetics exhibit interethnic variability, Asians exhibiting an increased bioavailability with regard to Mexicans and Caucasians. Data suggest that these differences are due to body weight.

Prediction of seriniquinone-drug interactions by in vitro inhibition of human cytochrome P450 enzymes

Seriniquinone is a secondary metabolite isolated from a rare marine bacterium of the genus Serinicoccus. This natural quinone is highlighted for its selective cytotoxic activity toward melanoma cancer cells, in which rapid metastatic properties are still a challenge for clinical treatment of malignant melanoma. The progress of seriniquinone as a promising bioactive molecule for drug development requires the assessment of its clinical interaction potential with other drugs. This study aimed to investigate the in vitro inhibitory effects of seriniquinone on the main human CYP450 isoforms involved in drug metabolism. The results showed strong inhibition of CYP1A2, CYP2E1 and CYP3A, with IC₅₀ values up to 1.4 μM, and moderate inhibition of CYP2C19, with IC₅₀ value >15 μM. Detailed experiments performed with human liver microsomes showed that the inhibition of CYP450 isoforms can be explained by competitive and non-competitive inhibition mechanisms. In addition, seriniquinone demonstrated to be an irreversible and time-dependent inhibitor of CYP1A2 and CYP3A. The low inhibition constants values obtained experimentally suggest that concomitant intake of seriniquinone with drug metabolized by these isoforms should be carefully monitored for adverse effects or therapeutic failure.

MDMA-Associated Liver Toxicity: Pathophysiology, Management, and Current State of Knowledge

3,4-Methylenedioxymethamphetamine (MDMA, ecstasy) has become a popular recreational drug of abuse among young adults, partly because of the belief that it is relatively safe compared with other drugs with the same stimulant and hallucinogenic effects. However, MDMA use has been associated with a wide spectrum of organ toxicities, with the liver being severely affected by its deleterious effects. This article discusses the essential pharmacology of MDMA and describes the effects MDMA has on various organ systems of the body, with particular focus on the liver. The putative mechanisms by which MDMA can cause liver damage are explored, with emphasis on patient-related factors that explain why some individuals are more susceptible than others to damage from MDMA. The incidence of hepatotoxicity related to MDMA use is presented, and the nursing management of patients who develop acute liver failure due to MDMA overuse is explored in light of current evidence.

Phenoconversion of CYP2D6 by inhibitors modifies aripiprazole exposure

The efficacy of aripiprazole therapy and the risk of adverse reactions are influenced by substantial inter-individual variability in aripiprazole metabolizing capacity. In vitro studies assigned the potential role in aripiprazole metabolism to CYP2D6 and CYP3A enzymes; therefore, the association between the steady-state aripiprazole plasma concentrations and patients' CYP2D6 and CYP3A statuses (CYP2D6, CYP3A4, and CYP3A5 genotypes, and CYP3A4 expression) and/or co-medication with CYP function modifying medications has been investigated in 93 psychiatric patients on stable aripiprazole therapy. The patients' CYP2D6 genotype had a major effect on aripiprazole plasma concentrations, whereas contribution of CYP3A genotypes and CYP3A4 expression to aripiprazole clearance were considered to be minor or negligible. The role of CYP3A4 expression in aripiprazole metabolism did not predominate even in the patients with nonfunctional CYP2D6 alleles. Furthermore, dehydroaripiprazole exposure was also CYP2D6 genotype-dependent. Dehydroaripiprazole concentrations were comparable with aripiprazole levels in patients with functional CYP2D6 alleles, and 35% or 22% of aripiprazole concentrations in patients with one or two non-functional CYP2D6 alleles, respectively. The concomitant intake of CYP2D6 inhibitors, risperidone, metoprolol, or propranolol was found to increase aripiprazole concentrations in patients with at least one wild-type CYP2D6*1 allele. Risperidone and 9-hydroxy-risperidone inhibited both dehydrogenation and hydroxylation of aripiprazole, whereas metoprolol and propranolol blocked merely the formation of the active dehydroaripiprazole metabolite, switching towards the inactivation pathways. Patients' CYP2D6 genotype and co-medication with CYP2D6 inhibitors can be considered to be the major determinants of aripiprazole pharmacokinetics. Taking into account CYP2D6 genotype and co-medication with CYP2D6 inhibitors may improve the outcomes of aripiprazole therapy.

Characterizing Fentanyl Variability Using Population Pharmacokinetics in Pediatric Burn Patients

Opioids are essential first line analgesics for pain management after burn injury. Opioid dosing remains challenging in burn patients, particularly in children, due to the immense variability in efficacy between patients. Opioid pharmacokinetics are altered in burned children, increasing variability and obviating dosing regimens extrapolated from adult-data. The present study aimed to characterize variability in fentanyl pharmacokinetics and identify significant contributors to variability in children with ≥10% total body surface area burn requiring fentanyl during routine wound care. We recorded patient demographics and clinical data. Blood samples were collected following fentanyl administration for pharmacokinetics at time 0, 30, 60, 120, and 240 minutes on day of admission and repeated on days 3 and 7. Serum fentanyl concentrations were quantified using tandem liquid chromatography mass spectrometry. Population analysis was used to estimate pharmacokinetics parameters. Fourteen patients, 1.2-17 years, with burns from 10-50.5% were included in analysis. A two-compartment model with body weight as a covariate best described fentanyl pharmacokinetics for the overall population. The population clearance and intercompartmental clearance were 7.19 and 2.16 L/hour, respectively, and the volume of distribution for the central and peripheral compartments was 4.01 and 25.1 L, respectively. Individual patient parameter estimates had extensive variability. This study confirmed the high variability in pediatric burn patient fentanyl pharmacokinetics and demonstrates similarities and differences to other populations reported in literature. Further research is needed with a larger number of patients to extensively investigate the impact of burns, genetic polymorphisms, and other factors on fentanyl efficacy and patient outcomes.

Effect of Environmental Exposure and Pharmacogenomics on Drug Metabolism

BACKGROUND

Pesticides are major xenobiotic compounds and environmental pollutants, which are able to alter drug-metabolizing enzyme as well as pharmacokinetics of drugs. Subsequent to the release of the human genome project, genetic variations (polymorphism) become an integral part of drug development due to their influence on disease susceptibility/ progression of the disease and their impact on drug absorption, distribution, metabolism of active metabolites and finally excretion of the drug. Genetic polymorphisms crucially regulate pharmacokinetics and pharmacodynamics of drugs under the influence of physiological condition, lifestyle, as well as pathological conditions collectively.

OBJECTIVE

To review all the evidence concerning the effect of environmental exposure on drug metabolism with reference to pharmacogenomics.

METHODS

Scientific data search and review of basic, epidemiological, pharmacogenomics and pharmacokinetics studies were undertaken to evaluate the influence of environmental contaminants on drug metabolism.

RESULTS

Various environmental contaminants like pesticides effectively alter drug metabolism at various levels under the influence of pharmacogenomics, which interferes with pharmacokinetics of drug metabolism. Genetic polymorphism of phase I and phase II xenobiotic-metabolizing enzymes remarkably alters disease susceptibility as well as the progression of disease under the influence of various environmental contaminants at various levels.

CONCLUSION

Individual specific drug response may be attributed to a large variety of factors alone or in combination ranging from genetic variations (SNP, insertion, deletion, duplication etc.) to physiological setting (gender, age, body size, and ethnicity), environmental or lifestyle factors (radiation exposure, smoking, alcohol, nutrition, exposure to toxins, etc.); and pathological conditions (obesity, diabetes, liver and renal function).

The Synergistic Antitumor Effect of Tanshinone IIA Plus Adriamycin on Human Hepatocellular Carcinoma Xenograft in BALB/C Nude Mice and Their Influences on Cytochrome P450 CYP3A4 In Vivo

OBJECTIVE

Hepatocellular carcinoma is one of the most common diseases that seriously threaten human life and health. In this study, we evaluated the inhibitory effect of tanshinone IIA (Tan IIA) combined with adriamycin (ADM) on human hepatocellular carcinoma and developed a platform to assess the function if Chinese herbal ingredients combined with chemotherapy drugs have synergistic antitumor effects in vivo.

METHODS

Established animal model of human hepatocarcinoma HepG2 cell in nude mice. Mice were divided into model control group, Tan IIA group, ADM group, and Tan IIA + ADM group. The changes from general condition, weight, tumor volume, and inhibition rate were observed. The data were gathered from serum AST level and histopathological changes. The content and activity of cytochrome P450 were determined by spectrophotometric analysis. CYP3A4 protein expression was analyzed by western blotting. The binding model crystal structure of Tan IIA and ADM with pregnane X receptor (PXR) was evaluated by Discovery Studio 2.1.

RESULTS

A combination of Tan IIA with ADM could improve life quality by relieving ADM toxicity, decreasing tumor volume, declining serum AST level, and improving liner pathological section in tumor-bearing mice. The inhibitory rates of Tan IIA, ADM, and cotreatment were 32.77%, 60.96%, and 73.18%, respectively. The Tan IIA group significantly enhanced the content of cytochrome b5, P450, and erythromycin-N-demethylase activity. CYP3A4 protein expression was enhanced obviously by the Tan IIA + ADM group. Virtual molecular docking showed that both Tan IIA and ADM could be stably docked with the same binding site of PXR but different interactions.

CONCLUSIONS

Tan IIA in combination with ADM could improve the life quality in tumor-bearing mice and enhance the antitumor effect. The Tan IIA group increased the concentration of cytochrome P450 enzymes and activity. Combined Tan IIA with ADM could upregulate the CYP3A4 protein expression and make relevant interaction with protein PXR by virtual docking.

Bone development and remodeling in metabolic disorders

There are many metabolic disorders that present with bone phenotypes. In some cases, the pathological bone symptoms are the main features of the disease whereas in others they are a secondary characteristic. In general, the generation of the bone problems in these disorders is not well understood and the therapeutic options for them are scarce. Bone development occurs in the early stages of embryonic development where the bone formation, or osteogenesis, takes place. This osteogenesis can be produced through the direct transformation of the pre-existing mesenchymal cells into bone tissue (intramembranous ossification) or by the replacement of the cartilage by bone (endochondral ossification). In contrast, bone remodeling takes place during the bone's growth, after the bone development, and continues throughout the whole life. The remodeling involves the removal of mineralized bone by osteoclasts followed by the formation of bone matrix by the osteoblasts, which subsequently becomes mineralized. In some metabolic diseases, bone pathological features are associated with bone development problems but in others they are associated with bone remodeling. Here, we describe three examples of impaired bone development or remodeling in metabolic diseases, including work by others and the results from our research. In particular, we will focus on hereditary multiple exostosis (or osteochondromatosis), Gaucher disease, and the susceptibility to atypical femoral fracture in patients treated with bisphosphonates for several years.

Role of Genetic Polymorphisms of Cytochrome P450 2C19 in Pantoprazole Metabolism and Pantoprazole-based Helicobacter pylori Eradication Regimens

BACKGROUND

Cytochrome P450 (CYP450) enzymes play an important role in the metabolism of 70-80% of the currently used medications, including proton pump inhibitors. There are some data analyzing the impact of gene polymorphisms of CYP450 enzymes on most widely used PPIs, such as omeprazole, however, the data on pantoprazole are highly lacking.

OBJECTIVE

To summarize the most recent publications and studies on the role of polymorphisms of the genes encoding CYP450 enzyme 2C19 in the metabolism of pantoprazole and pantoprazole based Helicobacter pylori eradication regimens.

METHODS

We performed a non-systematic search of the available literature on the selected topic.

RESULTS AND CONCLUSION

The data on cytochrome P450 gene polymorphisms and their role in pantoprazole metabolism and pantoprazole based Helicobacter pylori eradication remain conflicting. Individual differences in pantoprazole metabolism might be partly related to genetic polymorphisms of CYP450 enzymes. Most of the studies support the observation that cytochrome 2C19 polymorphisms have an impact on the pharmacokinetics of pantoprazole and its therapeutic effects: poor metabolizers of PPIs are more likely to have a better response to pantoprazole therapy and achieve better H. pylori eradication rates compared to rapid metabolizers. The determination of alleles that are associated with decreased (e.g., *2, *3 alleles) or increased (e.g., *17 allele) cytochrome 2C19 enzyme activity might be used as predictive factors for the potential of acid suppression and the success of Helicobacter pylori eradication. Overall, currently available data do not provide robust evidence, therefore, the application of genetic polymorphisms of cytochrome enzymes in clinical practice still cannot be recommended as routine practice for personalized pantoprazole prescription strategies.

Correlation between CYP1A1 polymorphisms and susceptibility to glyphosate-induced reduction of serum cholinesterase: A case-control study of a Chinese population

Glyphosate (GLP) is one of the most common herbicides worldwide. The serum cholinesterase (ChE) may be affected when exposed to glyphosate. Reduction of serum ChE by herbicides is probably related to cytochrome P450 (CYP450) family polymorphisms. We suspect that the abnormal ChE caused by GLP could be correlated with the CYP family members. To determine whether CYP1B1 (rs1056827 and rs1056836) and CYP1A1 (rs1048943) gene polymorphisms and individual susceptibility to GLP-induced ChE abnormalities were interrelated in the Chinese Han population, we performed this genetic association study on a total of 230 workers previously exposed to GLP, including 115 cases with reduced serum ChE and 115 controls with normal serum ChE. Two even groups of cases and controls were enrolled. The CYP1A1 and CYP1B1 polymorphisms in both groups were genotyped using TaqMan. Subjects with the CYP1A1 rs619586 genotypes showed an increased risk of GLP-induced reduction of serum ChE, which was more evident in the following subgroups: female, > 35 years old, history of GLP exposure time <10 years and >10 years, nonsmoker and nondrinker. The results show that CYP1A1 rs619586 was significantly associated with the GLP-induced reduction in serum ChE and could be a biomarker of susceptibility for Chinese GLP exposed workers. Because of a large number of people exposed to glyphosate, this study has a significance in protecting their health.

Short- and medium-term impact of bariatric surgery on the activities of CYP2D6, CYP3A4, CYP2C9, and CYP1A2 in morbid obesity

Morbid obesity and bariatric surgery induce anatomical, physiological and metabolic alterations that may alter the body’s disposition of drugs. Current literature on this topic is limited and sometimes inconsistent. Cytochrome P450 (CYP) is a superfamily of enzymes that metabolize around 75% of all marketed drugs. The purpose of this study was to evaluate the impact of body mass index and bariatric surgery on CYP activities. Firstly, we evaluated the in vivo activity of 4 major CYP isoenzymes (CYP2D6, CYP3A4, CYP2C9, and CYP1A2) in normal weight, overweight, and morbidly obese individuals. Secondly, we assessed the short- (1 month) and medium-term (6 month) effects of the most commonly employed bariatric surgery techniques (laparoscopic sleeve gastrectomy and Roux-en-Y gastric bypass) on the activity of these enzymes. CYP3A4 activity was lower in morbidly obese individuals, compared to normal-weight controls. Interestingly, bariatric surgery normalized CYP3A4 activity. In comparison with normal-weight controls, morbidly obese individuals had higher CYP2D6 activity, which was only observed in individuals with two functional alleles for this isoenzyme. Neither body mass index nor surgery had significant effects on CYP2C9 and CYP1A2 activities. Overall, no relevant differences in CYP activities were found between surgical techniques. In conclusion, further studies should evaluate whether the observed alterations in CYP3A4 activity will require dose adjustments for CYP3A4 substrates especially in morbidly obese individuals before and after bariatric surgery.

Circulating Extracellular Vesicles Containing Xenobiotic Metabolizing CYP Enzymes and Their Potential Roles in Extrahepatic Cells Via Cell-Cell Interactions

The cytochrome P450 (CYP) family of enzymes is known to metabolize the majority of xenobiotics. Hepatocytes, powerhouses of CYP enzymes, are where most drugs are metabolized into non-toxic metabolites. Additional tissues/cells such as gut, kidneys, lungs, blood, and brain cells express selective CYP enzymes. Extrahepatic CYP enzymes, especially in kidneys, also metabolize drugs into excretable forms. However, extrahepatic cells express a much lower level of CYPs than hepatocytes. It is possible that the liver secretes CYP enzymes, which circulate via plasma and are eventually delivered to extrahepatic cells (e.g., brain cells). CYP circulation likely occurs via extracellular vesicles (EVs), which carry important biomolecules for delivery to distant cells. Recent studies have revealed an abundance of several CYPs in plasma EVs and other cell-derived EVs, and have demonstrated the role of CYP-containing EVs in xenobiotic-induced toxicity via cell–cell interactions. Thus, it is important to study the mechanism for packaging CYP into EVs, their circulation via plasma, and their role in extrahepatic cells. Future studies could help to find novel EV biomarkers and help to utilize EVs in novel interventions via CYP-containing EV drug delivery. This review mainly covers the abundance of CYPs in plasma EVs and EVs derived from CYP-expressing cells, as well as the potential role of EV CYPs in cell–cell communication and their application with respect to novel biomarkers and therapeutic interventions.

Human Pharmacokinetic Parameters of Orally Administered Δ9-Tetrahydrocannabinol Capsules Are Altered by Fed Versus Fasted Conditions and Sex Differences

Background: There is variability in the reported Δ⁹-tetrahydrocannabinol (THC) and 11-hydroxy-tetrahydrocannabinol (11-OH-THC) pharmacokinetic (PK) and pharmacodynamic (PD) parameters between studies and there is limited investigation into how the presence of food or sex affect these parameters. In this study, we examined the PK and PD parameters of an encapsulated THC extract and its major active metabolite, 11-OH-THC, under different fed states. Methods: The study was a single-dose, randomized, double-blinded, four-way crossover investigation. THC capsules (1 or 2×5 mg) were administered to 28 healthy adults (13 females: 15 males) under a fasted condition or after a high-fat meal. Blood samples were collected and PK parameters were determined through noncompartmental analysis. Adverse events (AEs), cognitive function (through completion of digit symbol substitution tests), blood pressure, and heart rate were also recorded. Results: The presence of high-fat food significantly enhanced time to peak plasma concentration (T _max) and area under the curve (AUC_0-24) for both THC and 11-OH-THC and reduced THC's apparent volume of distribution (V _z/F) and apparent clearance (Cl/F). Females had a significantly greater peak plasma concentration (C _max) compared with males after 5 mg THC in a fasted state. No cardiovascular or cognitive effects and only mild AEs (somnolence, fatigue, and euphoric mood) were reported. Conclusion: These findings may help to inform the guidelines provided by governing health bodies on the effects of cannabis, such as time to onset and duration of action, and aid health care practitioners in their prescribing practices. Furthermore, the doses used in this study are safe to consider for future interventional studies in disease conditions where THC has been shown to have therapeutic efficacy.

Systematic exploration of predicted destabilizing nonsynonymous single nucleotide polymorphisms (nsSNPs) of human aldehyde oxidase: A Bio-informatics study

Aldehyde Oxidase (hAOX1) is a cytosolic enzyme involved in the metabolism of drugs and xenobiotic compounds. The enzyme belongs to the xanthine oxidase (XO) family of Mo containing enzyme and is a homo-dimer of two 150 kDa monomers. Nonsynonymous Single Nucleotide Polymorphisms (nsSNPs) of hAOX1 have been reported as affecting the ability of the enzyme to metabolize different substrates. Some of these nsSNPs have been biochemically and structurally characterized but the lack of a systematic and comprehensive study regarding all described and validated nsSNPs is urgent, due to the increasing importance of the enzyme in drug development, personalized medicine and therapy, as well as in pharmacogenetic studies. The objective of the present work was to collect all described nsSNPs of hAOX1 and utilize a series of bioinformatics tools to predict their effect on protein structure stability with putative implications on phenotypic functional consequences. Of 526 nsSNPs reported in NCBI-dbSNP, 119 are identified as deleterious whereas 92 are identified as nondeleterious variants. The stability analysis was performed for 119 deleterious variants and the results suggest that 104 nsSNPs may be responsible for destabilizing the protein structure, whereas five variants may increase the protein stability. Four nsSNPs do not have any impact on protein structure (neutral nsSNPs) of hAOX1. The prediction results of the remaining six nsSNPs are nonconclusive. The in silico results were compared with available experimental data. This methodology can also be used to identify and prioritize the stabilizing and destabilizing variants in other enzymes involved in drug metabolism.

Effects of 24 CYP2D6 variants found in Chinese population on the metabolism of clonidine in vitro

BACKGROUND AND OBJECTIVES

Clonidine has been clinically used to treat Tourette's syndrome for decades. There was research finding that clonidine possessed the best risk-benefit ratio, especially for patients associated with attention deficit hyperactivity disorder. CYP2D6 is a significant member of Cytochrome P450 enzymes. The genetic polymorphisms of CYP2D6 greatly affect the clinical effects of drugs even lead to side effects and medical malpractice. Our goal is to research the effect of CYP2D6 genetic polymorphism on the metabolism of clonidine and evaluate the functions of 22 CYP2D6 allelic variants in vitro, which were discovered in Chinese Han population recently.

METHODS

This study was carried out through a mature incubation system. The wild-type CYP2D6*1 and 24 variants (CYP2D6*2, CYP2D6*10 and 22 novel CYP2D6 variants) were expressed in insect cells, and the catalytic activity of all the variants were assessed by substrate clonidine. Metabolite 4-OH clonidine was accurately detected via ultra-performance liquid-chromatography tandem mass spectrometry to evaluate the effect of CYP2D6 genetic polymorphism on the clonidine.

RESULT

Among the 22 novel CYP2D6 variants, the intrinsic clearance (Vmax/Km) of 21 variants were significantly decreased (from 1.53% to 83.25%) compared to the wild-type. In particular, the following seven variants (CYP2D6* 2, CYP2D6* 10, CYP2D6* 93, CYP2D6* 95, E215K, V327 M and R497C) attract more attention, of which the intrinsic clearance decreased more than 70% compared to the wild-type. Because the variants with significantly reduced intrinsic clearance are more likely to cause adverse reactions than the variants with increased or little changed intrinsic clearance. In addition, the related pharmacokinetic parameters of CYP2D6*92 and CYP2D6*96 could not be acquired for the defect of CYP2D6 nucleotide.

CONCLUSION

We comprehensively evaluated the effect of 22 novel CYP2D6 variants on the metabolism of clonidine for the first time and hoped corresponding data provide a reference for metabolism of clonidine for further studies in vivo, and extend our understanding of the clinical drug toxicity or ineffectiveness by CYP2D6 genetic polymorphism.

Long-term functional maintenance of primary human hepatocytes in vitro

The maintenance of terminally differentiated cells, especially hepatocytes, in vitro has proven challenging. Here we demonstrated the long-term in vitro maintenance of primary human hepatocytes (PHHs) by modulating cell signaling pathways with a combination of five chemicals (5C). 5C-cultured PHHs showed global gene expression profiles and hepatocyte-specific functions resembling those of freshly isolated counterparts. Furthermore, these cells efficiently recapitulated the entire course of hepatitis B virus (HBV) infection over 4 weeks with the production of infectious viral particles and formation of HBV covalently closed circular DNA. Our study demonstrates that, with a chemical approach, functional maintenance of PHHs supports long-term HBV infection in vitro, providing an efficient platform for investigating HBV cell biology and antiviral drug screening.

Cytochrome P450: genotype to phenotype

The cytochromes P450 comprise a family of enzymes that are responsible for around three-quarters of all drug metabolism reactions that occur in human populations. Many isoforms of cytochrome P450 exist but most reactions are undertaken by CYP2C9, CYP2C19, CYP2D6 and CYP3A4. This brief review focusses on the first three isozymes which exhibit polymorphism of phenotype.If there is a wide variation in drug metabolising capacity within the population, this may precipitate clinical consequences and influence the drug treatment of patients. Such problems range from a lack of efficacy to unanticipated toxicity. In order to minimise untoward events and "personalise" a patient's treatment, efforts have been made to discover an individual's drug metabolism status. This requires knowledge of the subject's phenotype at the time of clinical treatment. Since such testing is difficult, time-consuming and costly, the simpler approach of genotyping has been advocated.However, the correlation between genotype and phenotype is not good, with values of up to 50% misprediction being reported. Genotype-assisted forecasts cannot therefore be used with confidence to replace actual phenotype measurements. Obfuscating factors discussed include gene splicing, single nucleotide polymorphisms, epigenetics and microRNA, transcription regulation and multiple gene copies.

Association of CYP1A1 M2 (A2455G) Polymorphism with Susceptibility to Breast Cancer in Mazandaran Province, Northern Iran: A Case-control Study

Background:

Breast cancer is one of the most frequent women malignancies in the world. The cytochrome P450 1A1 (CYP1A1) is a key enzyme in xenobiotics metabolism. Moreover, CYP1A1 plays a critical role in the etiology of breast cancer by involving in 2-hydroxylation of estrogen. Therefore, single-nucleotide polymorphisms (SNPs) of its coding gene have been verified to be important in cancer susceptibility. The aim of the study was to evaluate the association of CYP1A1 M2 (A2455G) includes rs1048943 of this SNP polymorphism with the risk of breast cancer in Mazandaran province.

Methods:

Ninety-six breast cancer patients with known clinicopathological characters and 110 healthy women as control were genotyped for CYP1A1 M2 polymorphisms by the restriction fragment length polymorphism technique.

Results:

The analysis of CYP1A1 gene (polymorphism M2) showed that the frequency of homozygous wild genotypes (AA), heterozygous (AG), and mutant genotype (GG) in the patient group, respectively, 78%, 22%, and 0%, and also the frequency of genotypes AA, AG, and GG in healthy included 82%, 16%, and 2%, respectively. Statistical analysis by Logistic regression model at P < 0.05 showed no significant correlation between polymorphisms in CYP1A1M2 and breast cancer risk (odds ratio = 0.84, confidence interval = 0.33–2.17).

Conclusions:

The results indicated that the M2 allelic genotypes were significantly associated neither with breast cancer risk nor with clinicopathological characteristics in Mazandaran province.

Copy number variation profiling in pharmacogenetics CYP-450 and GST genes in Colombian population

BACKGROUND

Copy Number variation (CNVs) in genes related to drug absorption, distribution, metabolism and excretion (ADME) are relevant in the interindividual variability of drug response. Studies of the CNVs in ADME genes in Latin America population are lacking. The objective of the study was to identify the genetic variability of CNVs in CYP-450 and GST genes in a subgroup of individuals of Colombian origin.

METHODS

Genomic DNA was isolated from 123 healthy individuals from a Colombian population. Multiplex Ligation-Dependent Probe Amplification (MLPA) was performed for the identification of CNVs in 40 genomic regions of 11 CYP-450 and 3 GST genes. The genetic variability, allelic and genotypic frequencies were analyzed.

RESULTS

We found that 13 out of 14 genes had CNVs: 5 (35.7%) exhibited deletions and duplications, while 8 (57.1%) presented either deletions or duplications.. 33.3% of individuals carried deletions and duplications while 49.6% had a unique type of CNV (deletion or duplication). The allelic frequencies of the CYP and GST genes were 0 to 47.6% (allele null), 0 to 17.5% (duplicated alleles) and 37 to 100% (normal alleles).

CONCLUSIONS

Our results describe, for the first time, the genomic profile of CNVs in a subgroup of Colombian population in GST and CYP-450 genes. GST genes indicated greater genetic variability than CYP-450 genes. The data obtained contributes to the knowledge of genetic profiles in Latin American subgroups. Although the clinical relevance of CNVs has not been fully established, it is a valuable source of pharmacogenetic variability data with potential involvement in the response to medications.

Update on the pharmacogenomics of pain management

Pharmacogenomics is the study of genetic variants that impact drug effects through changes in a drug’s pharmacokinetics and pharmacodynamics. Pharmacogenomics is being integrated into clinical pain management practice because variants in individual genes can be predictive of how a patient may respond to a drug treatment. Pain is subjective and is considered challenging to treat. Furthermore, pain patients do not respond to treatments in the same way, which makes it hard to issue a consistent treatment regimen for all pain conditions. Pharmacogenomics would bring consistency to the subjective nature of pain and could revolutionize the field of pain management by providing personalized medical care tailored to each patient based on their gene variants. Additionally, pharmacogenomics offers a solution to the opioid crisis by identifying potentially opioid-vulnerable patients who could be recommended a nonopioid treatment for their pain condition. The integration of pharmacogenomics into clinical practice creates better and safer healthcare practices for patients. In this article, we provide a comprehensive history of pharmacogenomics and pain management, and focus on up to date information on the pharmacogenomics of pain management, describing genes involved in pain, genes that may reduce or guard against pain and discuss specific pain management drugs and their genetic correlations.

A two-step lineage reprogramming strategy to generate functionally competent human hepatocytes from fibroblasts

Terminally differentiated cells can be generated by lineage reprogramming, which is, however, hindered by incomplete conversion with residual initial cell identity and partial functionality. Here, we demonstrate a new reprogramming strategy by mimicking the natural regeneration route, which permits generating expandable hepatic progenitor cells and functionally competent human hepatocytes. Fibroblasts were first induced into human hepatic progenitor-like cells (hHPLCs), which could robustly expand in vitro and efficiently engraft in vivo. Moreover, hHPLCs could be efficiently induced into mature human hepatocytes (hiHeps) in vitro, whose molecular identity highly resembles primary human hepatocytes (PHHs). Most importantly, hiHeps could be generated in large quantity and were functionally competent to replace PHHs for drug-metabolism estimation, toxicity prediction and hepatitis B virus infection modeling. Our results highlight the advantages of the progenitor stage for successful lineage reprogramming. This strategy is promising for generating other mature human cell types by lineage reprogramming.

A Pilot Study towards the Impact of Type 2 Diabetes on the Expression and Activities of Drug Metabolizing Enzymes and Transporters in Human Duodenum

To characterize effects of type 2 diabetes (T2D) on mRNA expression levels for 10 Cytochromes P450 (CYP450s), two carboxylesterases, and three drug transporters (ABCB1, ABCG2, SLCO2B1) in human duodenal biopsies. To compare drug metabolizing enzyme activities of four CYP450 isoenzymes in duodenal biopsies from patients with or without T2D. mRNA levels were quantified (RT-qPCR) in human duodenal biopsies obtained from patients with (n = 20) or without (n = 16) T2D undergoing a scheduled gastro-intestinal endoscopy. CYP450 activities were determined following incubation of biopsy homogenates with probe substrates for CYP2B6 (bupropion), CYP2C9 (tolbutamide), CYP2J2 (ebastine), and CYP3A4/5 (midazolam). Covariables related to inflammation, T2D, demographic, and genetics were investigated. T2D had no major effects on mRNA levels of all enzymes and transporters assessed. Formation rates of metabolites (pmoles mg protein⁻¹ min⁻¹) determined by LC-MS/MS for CYP2C9 (0.48 ± 0.26 vs. 0.41 ± 0.12), CYP2J2 (2.16 ± 1.70 vs. 1.69 ± 0.93), and CYP3A (5.25 ± 3.72 vs. 5.02 ± 4.76) were not different between biopsies obtained from individuals with or without T2D (p > 0.05). No CYP2B6 specific activity was measured. TNF-α levels were higher in T2D patients but did not correlate with any changes in mRNA expression levels for drug metabolizing enzymes or transporters in the duodenum. T2D did not modulate expression or activity of tested drug metabolizing enzymes and transporters in the human duodenum. Previously reported changes in drug oral clearances in patients with T2D could be due to a tissue-specific disease modulation occurring in the liver and/or in other parts of the intestines.

Role of the Aryl Hydrocarbon Receptor/ARNT/Cytochrome P450 System in Pulmonary Vascular Diseases

RATIONALE

CYPs (cytochrome p450) are critically involved in the metabolism of xenobiotics and toxins. Given that pulmonary hypertension is strongly associated with environmental exposure, we hypothesize that CYPs play a role in the development and maintenance of pathological vascular remodeling.

OBJECTIVE

We sought to identify key CYPs that could link drug or hormone metabolism to the development of pulmonary hypertension.

METHODS AND RESULTS

We searched in Medline (PubMed) database, as well as http://www.clinicaltrials.gov, for CYPs associated with many key aspects of pulmonary arterial hypertension including, but not limited to, severe pulmonary hypertension, estrogen metabolism, inflammation mechanisms, quasi-malignant cell growth, drug susceptibility, and metabolism of the pulmonary arterial hypertension-specific drugs.

CONCLUSIONS

We postulate a hypothesis where the AhR (aryl hydrocarbon receptor) mediates aberrant cell growth via expression of different CYPs associated with estrogen metabolism and inflammation.

Characterization of Porcine Hepatic and Intestinal Drug Metabolizing CYP450: Comparison with Human Orthologues from A Quantitative, Activity and Selectivity Perspective

Over the past two decades, the pig has gained attention as a potential model for human drug metabolism. Cytochrome P450 enzymes (CYP450), a superfamily of biotransformation enzymes, are pivotal in drug metabolism. Porcine CYP450 has been demonstrated to convert typical substrates of human CYP450. Nevertheless, knowledge and insight into porcine CYP450 quantity and substrate selectivity is scant, especially regarding intestinal CYP450. The current study aimed to map the quantities of hepatic and intestinal CYP450 in the conventional pig by using a proteomic approach. Moreover, the selectivity of the six most common used probe substrates (phenacetin, coumarin, midazolam, tolbutamide, dextromethorphan, and chlorzoxazone) for drug metabolizing enzyme subfamilies (CYP1A, CYP2A, CYP3A, CYP2C, CYP2D and CYP2E respectively), was investigated. Hepatic relative quantities were 4% (CYP1A), 31% (CYP2A), 14% (CYP3A), 10% (CYP2C), 28% (CYP2D) and 13% (CYP2E), whereas for the intestine only duodenal CYP450 could be determined with 88% for CYP3A and 12% for CYP2C. Furthermore, the results indicate that coumarin (CYP2A), midazolam (CYP3A), tolbutamide (CYP2C), and dextromethorphan (CYP2D) are as selective for porcine as for human CYP450. However, phenacetin (CYP1A2) and chlorzoxazone (CYP2E1) are less selective for the specific enzyme, despite similarities in selectivity towards the different enzymes involved compared to humans.

Functional characterization of 27 CYP3A4 protein variants to metabolize regorafenib in vitro

AIM

Regorafenib is a tyrosine kinase inhibitor that is mainly metabolized by CYP3A4. The genetic polymorphism of CYP3A4 would contribute to differences in metabolism of regorafenib. Previously, we had discovered several novel CYP3A4 variants. However, the catalytic characteristics of these 27 CYP3A4 variants on oxidizing regorafenib have not being determined. The purpose of this study was to investigate the catalytic characteristics of 27 CYP3A4 protein variants on the oxidative metabolism of regorafenib in vitro.

METHOD

Wild-type CYP3A4.1 or other variants was incubated with 0.5-20 μmol/L regorafenib for 30 minutes. After sample processing, regorafenib-N-oxide, a primary metabolite, was detected by ultra-performance liquid chromatography-tandem mass spectrometry system.

RESULT

CYP3A4.20 had no detectable enzyme activity compared with wild-type CYP3A4.1; five variants (CYP3A4.5, .16, .19, .24, .29) exhibited similar clearance value with CYP3A4.1; four variants (CYP3A4.14, .15, .28, .31) displayed increased enzymatic activities, while remaining variants showed markedly decreased intrinsic clearance values.

CONCLUSION

This study is the first to investigate the function of 27 CYP3A4 protein variants on the metabolism of regorafenib in vitro, and it may provide some valuable information for further research in clinic.

A Framework Model for a Contextualized and Integrated Warfarin Therapy Case in a Master of Pharmacy Program

Objective. To develop and integrate a case study on warfarin into a clinical pharmacy workshop. Methods. A framework model was designed and used to create a case study on warfarin therapy. The case study was implemented in a third-year Master of Pharmacy course. Student feedback was obtained using an online questionnaire and two focus groups. Results. All students agreed that the case study successfully integrated the science of warfarin and concepts of pharmacy practice. The majority of students (94%) agreed that this approach helped them to understand the science of warfarin more than a traditional lecture would have. Students felt the time allocated to the workshop was too short. Conclusion. An integrated case study provides a learning environment that emphasizes the contextualization of chemistry and pharmacology into a clinical pharmacy setting.