Implications of analytical nanoscience in pharmaceutical and biomedical fields: A critical view.

This review summarizes recent progress performed in the design and application of analytical tools and methodologies using nanomaterials for pharmaceutical analysis, and specifically new nanomedicines at distinct phases of development and translation from preclinical to clinical stages. Over the last 10-15 years, a growing number of studies have utilized various nanomaterials, including carbon-based, metallic nanoparticles, polymeric nanomaterials, materials based on biological molecules, and composite nanomaterials as tools for improving the analysis of pharmaceutical products. New and more complex nanomaterials are currently being explored to influence different stages of the analytical process. These materials provide unique properties to support the extraction of analytes in complex samples, increase the selectivity and efficiency of chromatographic separations, and improve the analytical properties of many sensor applications. Indeed, nanomaterials, including electrochemical detection approaches and biosensing, are expanding at a remarkable rate. Furthermore, the analytical performance of numerous approaches to determine drugs in different matrices can be significantly improved in terms of precision, detection limits, selectivity, and time of analysis. However, the quality control and metrological characterization of the currently synthesized nanomaterials still depend on the development of new and improved analytical methodologies, and the application of specific and improved instrumentation. Therefore, there is still much to explore about the properties of nanomaterials which need to be determined even more precisely and accurately.

Pharmacogenomic biomarker information on drug labels of the Spanish Agency of Medicines and Sanitary products: evaluation and comparison with other regulatory agencies.

This work aimed to analyse the pharmacogenetic information in the Spanish Drug Regulatory Agency (AEMPS) Summary of Products Characteristics (SmPC), evaluating the presence of pharmacogenetic biomarkers, as well as the associated recommendations. A total of 55.4% of the 1891 drug labels reviewed included information on pharmacogenetic biomarker(s). Pharmacogenomic information appears most frequently in the "antineoplastic and immunomodulating agents", "nervous system", and "cardiovascular system" Anatomical Therapeutic Chemical groups. A total of 509 different pharmacogenetic biomarkers were found, of which CYP450 enzymes accounted for almost 34% of the total drug-biomarker associations evaluated. A total of 3679 drug-biomarker pairs were identified, 102 of which were at the 1A level (PharmGKB® classification system), and 33.33% of these drug-pharmacogenetic biomarker pairs were assigned to "actionable PGx", 12.75% to "informative PGx", 4.9% to "testing recommended", and 4.9% to "testing required". The rate of coincidence in the assigned PGx level of recommendation between the AEMPS and regulatory agencies included in the PharmGKB® Drug Label Annotations database (i.e., the FDA, EMA, SWISS Medic, PMDA, and HCSC) ranged from 45% to 65%, being 'actionable level' the most frequent. On the other hand, discrepancies between agencies did not exceed 35%. This study highlights the presence of relevant pharmacogenetic information on Spanish drug labels, which would help avoid interactions, toxicity, or lack of treatment efficacy.

A one-year follow-up study of treatment-compliant suicide attempt survivors: relationship of CYP2D6-CYP2C19 and polypharmacy with suicide reattempts.

This study of a cohort of 1-year treatment-compliant survivors of a suicide attempt examined for the first time whether a high CYP2D6-CYP2C19 metabolic capacity (pharmacogenes related to psychopathology, suicide, and attempt severity) and/or polypharmacy treatments predicted repeat suicide attempts, adjusting for sociodemographic and clinical factors as confounders. Of the 461 (63% women) consecutively hospitalized patients who attempted suicide and were evaluated and treated after an index attempt, 191 (67.5% women) attended their 6- and 12-month follow-up sessions. Clinicians were blinded to the activity scores (AS) of their genotypes, which were calculated as the sum of the values assigned to each allele (CYP2C19 *2, *17; CYP2D6 *3, *4, *4xN, *5, *6, *10, wtxN). No differences were found in polypharmacy prescription patterns and the variability of CYP2D6 and CYP2C19 genotypes between adherents and dropouts, but the formers were older, with a higher frequency of anxiety and bipolar disorders and fewer alcohol and substance use disorders. The risk of reattempts was higher for CYP2D6 ultrarapid (AS > 2) metabolizers (ß = 0.561, p = 0.005) and violent suicide survivors (ß = -0.219, p = 0.042) if the attempt occurred during the first 6-month period, individuals with an increased number of MINI DSM-IV Axis I mental disorders (ß = 0.092, p = 0.032) during the second 6-month period and individuals with a combined high CYP2D6-CYP2C19 metabolic capacity (AS > 4) (ß = 0.345, p = 0.024) and an increased use of drugs other than antidepressants, anxiolytics-depressants and antipsychotics-lithium (ß = 0.088, p = 0.005) in multiple repeaters during both periods. CYP2D6 and CYP2C19 rapid metabolism and polypharmacy treatment for somatic comorbidities must be considered to prevent the severe side effects of short-term multiple suicide reattempts after a previous attempt.

Current perspectives on interethnic variability in multiple myeloma: Single cell technology, population pharmacogenetics and molecular signal transduction.

Multiple myeloma (MM) is an aggressive cancer characterised by malignancy of the plasma cells and a rising global incidence. The gold standard for optimum response is aggressive chemotherapy followed by autologous stem cell transplantation (ASCT). However, majority of the patients are above 60 years and this presents the clinician with complications such as ineligibility for ASCT, frailty, drug-induced toxicity and differential/partial response to treatment. The latter is partly driven by heterogenous genotypes of the disease in different subpopulations. In this review, we discuss emerging single cell technologies and applications in MM, population pharmacogenetics of MM, resistance to chemotherapy, genetic determinants of drug-induced toxicity, molecular signal transduction, as well as the role(s) played by epigenetics and noncoding RNAs including microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) that influence the risk and severity of the disease. Taken together, our discussions further our understanding of genetic variability in 'myelomagenesis' and drug-induced toxicity, augment our understanding of the myeloma microenvironment at the molecular and cellular level and provide a basis for developing precision medicine strategies to combat this malignancy.

Relationships between CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A4 metabolic phenotypes and genotypes in a Nicaraguan Mestizo population.

Interethnic variability in the drug-metabolizing capacity of CYP450 enzymes may lead to discrepancies in the relationship between genotypes and phenotypes worldwide. The present study was aimed to analyze for the first time whether there is a relationship between clinically relevant CYP450 genetic polymorphisms and their drug oxidation capacity (metabolic phenotype) in a population of healthy Nicaraguan volunteers. Two hundred and twelve participants were genotyped for CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4, and their actual metabolic phenotype (evaluated by the Metabolic Ratio, MR) was analyzed by using the CEIBA cocktail approach. The results showed the wide interindividual variability in all the studied enzymes and a significant difference (p < 0.004) in the activity of CYP1A2 between male and female subjects. The number of CYP2C19 (p < 0.0001) and CYP2D6 (p < 0.0001) active alleles were shown inversely correlated with their corresponding MR, although there were marked genotype-phenotype discrepancies. There was an actual enzyme capacity overlapping (MR) between genotypically Poor (gPMs) and Extensive Metabolizers (gEMs) of 3.14% subjects for CYP2D6 and 0.94% for CYP2C9. Similarly, there was an overlapping for metabolic phenotypes of 11.48% of genotypically ultrarapid metabolizers (gUMs) for CYP2C19 and 2.09% for CYP2D6 and gEMs. Therefore, the current approach for metabolic phenotype prediction based just on genotype does not predict properly for all individuals within this Nicaraguan Mestizo population, thus representing a potential barrier for the clinical implementation of personalized medicine in this region. However, it is necessary to improve the prediction of phenotype from genotype in order to improve the pharmacogenetic implementation in populations with specific ethnic backgrounds.

High prevalence of CYP2D6 ultrarapid metabolizers in a mestizo Colombian population in relation to Hispanic mestizo populations.

Background: Interethnic differences in CYP2D6 allele frequency have been demonstrated across Latin-American countries. Only one previous study describing CYP2D6 genotypes in Colombian population has been performed. Thus, this study aimed to evaluate the CYP2D6 genetic variability in a mestizo Colombian population, as well as the similarities and differences concerning other Hispanic mestizo (HM) populations. Methodology: Two hundred and twelve unrelated healthy Colombian subjects were studied, in which different CYP2D6 polymorphisms were analyzed by extra long-PCR and real-time PCR. Results & discussion: A high percentage of ultrarapid metabolizers (18.4%) was found, representing the highest frequency calculated within the HM populations studied. However, the percentage of poor metabolizers (4.7%) was similar to those previously reported in HM populations.

Current Insights into Interethnic Variability in Testicular Cancers: Population Pharmacogenetics, Clinical Trials, Genetic Basis of Chemotherapy- Induced Toxicities and Molecular Signal Transduction.

Testicular cancer is an aggressive malignancy with a rising incidence rate across the globe. Testicular germ cell tumors are the most commonly diagnosed cancers, and surgical removal of the testes is often a radical necessity along with chemotherapy and radiotherapy. While seminomas are receptive to radiotherapy as well as chemotherapy, non-seminomatous germ cell tumors respond to chemotherapy only. Due to the singular nature of testicular cancers with associated orchiectomy and mortality, it is important to study the molecular basis and genetic underpinnings of this group of cancers across male populations globally. In this review, we shed light on the population pharmacogenetics of testicular cancer, pediatric and adult tumors, current clinical trials, genetic determinants of chemotherapy-induced toxicity in testicular cancer, as well as the molecular signal transduction pathways operating in this malignancy. Taken together, our discussions will help in enhancing our understanding of genetic factors in testicular carcinogenesis and chemotherapy-induced toxicity, augment our knowledge of this aggressive cancer at the cellular and molecular level, as well as improve precision medicine approaches to combat this disease.

LC-MS determination of catecholamines and related metabolites in red deer urine and hair extracted using magnetic multi-walled carbon nanotube poly(styrene-co-divinylbenzene) composite.

A novel analytical methodology for the extraction and determination of catecholamines (dopamine, epinephrine and norepinephrine) and their metabolites DL-3,4-dihydroxyphenyl glycol and DL-3,4-dihydroxymandelic acid by LC-MS is developed and validated for its application to human and animal urine and hair samples. The method is based on the preliminary extraction of the analytes by a magnetic multi-walled carbon nanotube poly(styrene-co-divinylbenzene) composite. This is followed by a <9 min chromatographic separation of the target compounds in an Onyx Monolithic C18 column using a mixture of 0.01% (v/v) heptafluorobutyric acid in water and methanol at 500 µL min-1 flow rate. Detection limits within range from 0.055 to 0.093 µg mL-1, and precision values of the response and retention times of analytes were >90%. Accuracy values comprised the range 79.5-109.5% when the analytes were extracted from deer urine samples using the selected MMWCNT-poly(STY-DVB) sorbent. This methodology was applied to real red deer urine and hair samples, and concentrations within range from 0.05 to 0.5 µg mL-1 for norepinephrine and from 1.0 to 44.5 µg mL-1 for its metabolite 3,4-dihydroxyphenyl glycol were calculated. Analyses of red deer hair resulted in high amounts of 3,4-dihydroxyphenyl glycol (0.9-266.9 µg mL-1).

Screening and Preliminary Biochemical and Biological Studies of [RuCl(p-cymene)(N,N-bis(diphenylphosphino)-isopropylamine)][BF4] in Breast Cancer Models.

Breast cancer is the second leading cause of cancer death worldwide. Despite progress in drug discovery, identification of the correct population is the limiting factor to develop new compounds in the clinical setting. Therefore, the aim of this study is to evaluate the effects of a new metallodrug, [RuCl(p-cymene)(N,N-bis(diphenylphosphino)-isopropylamine)][BF4] (pnpRu-14), as a lead pnp-Ru compound by screening and preliminary biochemical and biological studies in different breast cancer subtypes. The results show that complex pnpRu-14 is much more effective in promoting in vitro cytotoxic effects on HER2+ and RH+/HER2- breast cancer than the reference metallodrugs cisplatin, carboplatin, or RAPTA-C. It is important to highlight that pnpRu-14 shows an impressive cytotoxicity against BT474 cells. Caspase-dependent apoptosis is the mechanism of action for these compounds. In addition, treatment of SKBR3, BT474, T47D, and MCF7 cancer cells with pnpRu-14 caused an accumulation of cells in the G0/G1 phase cells. The human serum albumin, DNA, and H1 histones binding properties of the lead compound are reported. Pharmacokinetic and biodistribution studies show a quick absorption of pnpRu-14 in serum with no significant accumulation in any of the tested organs. This work provides evidence to support the preclinical and clinical development of pnpRu-14 in breast cancer.

Frequency of CYP2C9 (*2, *3 and IVS8-109A>T) allelic variants, and their clinical implications, among Mexican patients with diabetes mellitus type 2 undergoing treatment with glibenclamide and metformin.

The majority of Mexican patients with diabetes mellitus type 2 (DMT2) (67.9-85.0%) are prescribed sulphonylureas (SUs), which are metabolized by cytochrome P450 2C9 (abbreviated as CYP2C9). SUs are a type of oral anti-diabetic compound which inhibit ATP-sensitive potassium channels, thus inducing glucose-independent insulin release by the ß-pancreatic cells. The wide variability reported in SU responses has been attributed to the polymorphisms of CYP2C9. The present study aimed to describe CYP2C9 polymorphisms (*2, *3 and IVS8-109T) within a sample of Mexican patients with DMT2, while suggesting the potential clinical implications in terms of glibenclamide response variability. From a sample of 248 patients with DMT2 who initially consented to be studied, those ultimately included in the study were treated with glibenclamide (n=11), glibenclamide combined with metformin (n=112) or metformin (n=76), and were subsequently genotyped using a reverse transcription-quantitative polymerase chain reaction (PCR), end-point allelic discrimination and PCR amplifying enzymatic restriction fragment long polymorphism. Clinical data were gathered through medical record revision. The frequencies revealed were as follows: CYP2C9*1/*1, 87.5%; *1/*2, 6.5%; *1/*3, 5.2%; and CYP2C9, IVS8-109A>T, 16.1%. Glibenclamide significantly reduced the level of pre-prandial glucose (P<0.01) and the percentage of glycated hemoglobin (%HbA1c; P<0.01) for IVS8-109A>T compared with combined glibenclamide and metformin treatment. Concerning the various treatments with respect to the different genotypes, the percentages obtained were as follows: Glibenclamide A/A, HbA1c<6.5=33.3%; glibenclamide + metformin A/A, HbA1c<6.5=24.6%; glibenclamide A/T, HbA1c<6.5=33.3%; glibenclamide + metformin A/T, HbA1c<6.5=25%; glibenclamide T/T, HbA1c<6.5=100%; and glibenclamide + metformin T/T, HbA1c<6.5=12.5%. Altogether, these results revealed that, although genetically customized prescriptions remain a desirable goal to increase the chances of therapeutic success, within the studied population neither allelic variants nor dosages demonstrated a clear association with biomarker levels. A key limitation of the present study was the lack of ability to quantify either the plasma concentrations of SU or their metabolites; therefore, further, precise experimental and observational studies are required.

Unprecedented high catecholamine production causing hair pigmentation after urinary excretion in red deer.

Hormones have not been found in concentrations of orders of magnitude higher than nanograms per milliliter. Here, we report urine concentrations of a catecholamine (norepinephrine) ranging from 0.05 to 0.5 g/l, and concentrations of its metabolite DL-3,4-dihydroxyphenyl glycol (DOPEG) ranging from 1.0 to 44.5 g/l, in wild male red deer Cervus elaphus hispanicus after LC-MS analyses. The dark ventral patch of male red deer, a recently described sexually selected signal, contains high amounts of DOPEG (0.9-266.9 mg/l) stuck in the hairs, while DOPEG is not present in non-darkened hair. The formation of this dark patch is explained by the chemical structure of DOPEG, which is a catecholamine-derived o-diphenol susceptible to be oxidized by air and form allomelanins, nitrogen-free pigments similar to cutaneous melanins; by its high concentration in urine; and by the urine spraying behavior of red deer by which urine is spread through the ventral body area. Accordingly, the size of the dark ventral patch was positively correlated with the concentration of DOPEG in urine, which was in turn correlated with DOPEG absorbed in ventral hair. These findings represent catecholamine concentrations about one million higher than those previously reported for any hormone in an organism. This may have favored the evolution of the dark ventral patch of red deer by transferring information on the fighting capacity to rivals and mates. Physiological limits for hormone production in animals are thus considerably higher than previously thought. These results also unveil a novel mechanism of pigmentation based on the self-application of urine over the fur.

Effects of Khat (Catha edulis) use on catalytic activities of major drug-metabolizing cytochrome P450 enzymes and implication of pharmacogenetic variations.

In a one-way cross-over study, we investigated the effect of Khat, a natural amphetamine-like psychostimulant plant, on catalytic activities of five major drug-metabolizing cytochrome P450 (CYP) enzymes. After a one-week Khat abstinence, 63 Ethiopian male volunteers were phenotyped using cocktail probe drugs (caffeine, losartan, dextromethorphan, omeprazole). Phenotyping was repeated after a one-week daily use of 400 g fresh Khat leaves. Genotyping for CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP3A5 were done. Urinary cathinone and phenylpropanolamine, and plasma probe drugs and metabolites concentrations were quantified using LC-MS/MS. Effect of Khat on enzyme activities was evaluated by comparing caffeine/paraxanthine (CYP1A2), losartan/losartan carboxylic acid (CYP2C9), omeprazole/5-hydroxyomeprazole (CYP2C19), dextromethorphan/dextrorphan (CYP2D6) and dextromethorphan/3-methoxymorphinan (CYP3A4) metabolic ratios (MR) before and after Khat use. Wilcoxon-matched-pair-test indicated a significant increase in median CYP2D6 MR (41%, p < 0.0001), and a marginal increase in CYP3A4 and CYP2C19 MR by Khat. Repeated measure ANOVA indicated the impact of CYP1A2 and CYP2C19 genotype on Khat-CYP enzyme interactions. The median MR increased by 35% in CYP1A2*1/*1 (p = 0.07) and by 40% in carriers of defective CYP2C19 alleles (p = 0.03). Urinary log cathinone/phenylpropanolamine ratios significantly correlated with CYP2D6 genotype (p = 0.004) and CYP2D6 MR (P = 0.025). Khat significantly inhibits CYP2D6, marginally inhibits CYP3A4, and genotype-dependently inhibit CYP2C19 and CYP1A2 enzyme activities.

A simple poly(styrene-co-divinylbenzene)-coated glass blood spot method for monitoring of seven antidepressants using capillary liquid chromatography-mass spectrometry.

A simple, rapid, selective and sensitive monitoring method for the simultaneous determination of the widely-prescribed antidepressants agomelatine, bupropion, citalopram, fluoxetine, mirtazapine, paroxetine, trazodone in just a human blood drop is here developed and validated. This methodology is based on the use of lab manufactured poly(styrene-co-divinylbenzene)-coated glass (PS-DVB) blood spot for the extraction of the analytes and their subsequent separation and detection by capillary liquid chromatography-mass spectrometry (CLC-MS). Briefly, 10 mm-side squares were punched out from blood spots collected on glass substrate coated by 10 µg of the PS-DVB polymer and eluted with 1.0 mL of 2.0% acetic acid in methanol. The analytes were then separated and detected in less than 20 min by capillary CLC-MS using a Jupiter 4 µm Proteo 90 Šcolumn and water: acetonitrile (20:80 v/v) and ammonium acetate (5 mM, pH 3.0) as mobile phase. Limit of detection (LOD) ranged from 0.018 to 0.038 µg mL-1, and remarkable precision values for the responses and retention times lower than 5.89% and 1.92% were calculated, respectively. Moreover, accuracy values ranging between 85% and 104% were obtained.

Determination of antidepressants in human urine extracted by magnetic multiwalled carbon nanotube poly(styrene-co-divinylbenzene) composites and separation by capillary electrophoresis.

Poly(styrene-co-divinylbenzene)-coated magnetic multiwalled carbon nanotube composite synthesized by in-situ high temperature combination and precipitation polymerization of styrene-co-divinylbenzene has been employed as a magnetic sorbent for the solid phase extraction of antidepressants in human urine samples. Fluoxetine, venlafaxine, citalopram and sertraline were, afterwards, separated and determined by capillary electrophoresis with diode array detection. The presence of magnetic multiwalled carbon nanotubes in native poly(styrene-co-divinylbenzene) not only simplified sample treatment but also enhanced the adsorption efficiencies, obtaining extraction recoveries higher than 89.5% for all analytes. Moreover, this composite can be re-used at least ten times without loss of efficiency and limits of detection ranging from 0.014 to 0.041 µg/mL were calculated. Additionally, precision values ranging from 0.08 to 7.50% and from 0.21 to 3.05% were obtained for the responses and for the migration times of the analytes, respectively.

CYP450 Genotype/Phenotype Concordance in Mexican Amerindian Indigenous Populations-Where to from Here for Global Precision Medicine?

Global precision medicine demands characterization of drug metabolism and phenotype variation in diverse populations, including the indigenous societies. A related question is the extent to which CYP450 drug metabolizing enzyme genotype and phenotype data are concordant and whether they can be used interchangeably. These issues are increasingly debated as precision medicine continues to expand as a popular research topic worldwide. We report here the first study in clinically relevant CYP450 drug metabolism phenotypes and genotypes in Mexican Amerindian indigenous subjects. In a large sample of 450 unrelated and medication free Mexican Amerindian indigenous healthy persons from four Mexican states (Chihuahua, Durango, Nayarit, and Sonora), we performed multiplexed phenotyping for the CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4 drug metabolizing enzymes using the CEIBA cocktail and genotyped the same pathways for functional polymorphic variation. Remarkable interindividual variability was found for the actual drug metabolizing capacity of all the enzymes analyzed, and, more specifically, the metabolic ratios calculated were significantly different across individuals with different number of active alleles for CYP2C9, CYP2C19, and CYP2D6. The drug metabolizing capacity "predicted" from the genotype determined was not in accordance with the actual capacity "measured" by phenotyping in several individuals for CYP2C9, CYP2C19, and CYP2D6. Consequently, a more extensive genotyping of the main CYP enzymes, including rare variants, together with the analysis of the actual drug metabolizing capacity using an appropriate phenotyping approach will add valuable information for accurate drug metabolism studies, especially useful in understudied populations such as Mexican Amerindians. In sum, this study demonstrates that current personalized medicine strategies based on "predicted" phenotype from genotyping of alleles with high frequency in European populations are not adequate for Mestizos and Native American populations.

Selective screening of glutaric acid acidurias by capillary electrophoresis-mass spectrometry.

A sensitive and selective method for the separation and quantification of the three organic acids 3-hydroxy-3-methylglutaric acid, 3-methylglutaric acid, and glutaric acid in human urine samples by CE with mass spectrometry detection has been developed. This methodology is faster, simpler and less time-consuming, than other methodologies previously described, and requires of reduced amounts of reagents as well. Samples are first filtered and then diluted in water. For the electrophoretic separation, a 20mM ammonium acetate and 10% methanol solution at pH 9.1 was selected as the running electrolyte. With 5-s hydrodynamic injection, detection limits ranging from 15.5 to 39.3µM and linear responses ranging from the LOQ calculated for each analyte to more than 400µM were obtained for the analysis of the different organic acids in less than 13min. Remarkable selectivity is achieved by mass spectrometry detection using 0.25% of formic acid in 50% v/v 2-propanol-water solution as sheath liquid, and enough sensitivity without interferences from the matrices was obtained as well. This methodology has revealed as an efficient approach to help the 3-hydroxy-3-methylglutaric aciduria diagnoses in order to discard or confirm the occurrence of the disease as of the presence or absence of the expected increased levels of these analytes in samples of potential patients.

Water pipe (Shisha, Hookah, Arghile) Smoking and Secondhand Tobacco Smoke Effects on CYP1A2 and CYP2A6 Phenotypes as Measured by Caffeine Urine Test.

Public policies to stop or reduce cigarette smoking and exposure to secondhand smoke and associated diseases have yielded successful results over the past decade. Yet, the growing worldwide popularity of another form of tobacco consumption, water pipe smoking, has received relatively less attention. To the best of our knowledge, no study to date has evaluated the effects of water pipe smoking on cytochrome P450 (CYP450) activities and drug interaction potential in humans, whereas only limited information is available on the impact of secondhand smoke on drug metabolism. In a sample of 99 healthy volunteers (28 water pipe smokers, 30 secondhand tobacco smoke exposed persons, and 41 controls), we systematically compared CYP1A2 and CYP2A6 enzyme activities in vivo using caffeine urine test. The median self-reported duration of water pipe smoking was 7.5 h/week and 3 years of exposure in total. The secondhand smoke group had a median of 14 h of self-reported weekly exposure to tobacco smoke indoor where a minimum of five cigarettes were smoked/hour for a total of 3.5 years (median). Analysis of variance did not find a significant difference in CYP1A2 and CYP2A6 activities among the three study groups (p > 0.05). Nor was there a significant association between the extent of water pipe or secondhand smoke exposure and the CYP1A2 and CYP2A6 activities (p > 0.05). Further analysis in a subsample with smoke exposure more than the median values also did not reveal a significant difference from the controls. Although we do not rule out an appreciable possible impact of water pipe smoke and secondhand smoke on in vivo activities of these two drug metabolism pathways, variability in smoke constituents from different tobacco consumption methods (e.g., water pipe) might affect drug metabolism in ways that might differ from that of cigarette smoke. Further studies in larger prospective samples are recommended to evaluate water pipe and secondhand tobacco smoke effects on CYP450 function, particularly at higher smoke exposure conditions.

Lessons from Cuba for Global Precision Medicine: CYP2D6 Genotype Is Not a Robust Predictor of CYP2D6 Ultrarapid Metabolism.

A long-standing question and dilemma in precision medicine is whether and to what extent genotyping or phenotyping drug metabolizing enzymes such as CYP2D6 can be used in real-life global clinical and societal settings. Although in an ideal world using both genotype and phenotype biomarkers are desirable, this is not always feasible for economic and practical reasons. Moreover, an additional barrier for clinical implementation of precision medicine is the lack of correlation between genotype and phenotype, considering that most of the current methods include only genotyping. Thus, the present study evaluated, using dextromethorphan as a phenotyping probe, the relationship between CYP2D6 phenotype and CYP2D6 genotype, especially for the ultrarapid metabolizer (UM) phenotype. We report in this study, to the best of our knowledge, the first comparative clinical pharmacogenomics study in a Cuban population sample (N = 174 healthy volunteers) and show that the CYP2D6 genotype is not a robust predictor of the CYP2D6 ultrarapid metabolizer (mUM) status in Cubans. Importantly, the ultrarapid CYP2D6 phenotype can result in a host of health outcomes, such as drug resistance associated with subtherapeutic drug concentrations, overexposure to active drug metabolites, and altered sensitivity to certain human diseases by virtue of altered metabolism of endogenous substrates of CYP2D6. Hence, phenotyping tests for CYP2D6 UMs appear to be a particular necessity for precision medicine in the Cuban population. Finally, in consideration of ethical and inclusive representation in global science, we recommend further precision medicine biomarker research and funding in support of neglected or understudied populations worldwide.