Pharmacogenetics and genomics最新文献

Objectives: Understanding the influence of fetal and maternal genetics on prenatal drug exposure could potentially improve benefit-risk evaluation. In this study, we investigated the impact of two functional polymorphisms in CYP2B6 on prenatal exposure to efavirenz.

Methods: Dried blood spot (DBS) samples were collected from HIV-positive pregnant women ( n  = 112) and their newborns ( n  = 107) at delivery. They were genotyped for single nucleotide polymorphisms in CYP2B6. Efavirenz was quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS).

Results: Significant correlations were observed in efavirenz concentration between maternal and newborn ( r  = 0.46, R2  = 0.21, P  < 0.001), and maternal and cord ( r  = 0.83, R2  = 0.68, P  < 0.001) samples. Median (interquartile range) newborn plasma-to-maternal plasma and cord-to-maternal plasma ratios were 0.85 (0.03-3.49) and 0.78 (0.23-1.96), respectively. Newborn efavirenz concentration in DBS varied significantly based on composite maternal CYP2B6 genotype: fast ( CYP2B6 516GG and 983TT, n  = 26), 747 ng/ml (602-1060); intermediate ( CYP2B6 516GT or 983TC n  = 50), 1177 ng/ml (898-1765); and slow ( CYP2B6 516GT and 983TC or 516TT or 983CC, n  = 14), 3094 ng/ml (2126-3812). Composite newborn CYP2B6 genotype was, however, not significantly associated with prenatal exposure. Efavirenz concentration in newborn stratified as fast ( n  = 25), intermediate ( n  = 36), and slow metabolizers ( n  = 19) from prenatal exposure was 999.7 (774-1285), 1240 (709-1984), and 1792 ng/ml (1201-3188), respectively.

Conclusion: The clinical relevance of the observed influence of maternal genetics on prenatal efavirenz exposure requires further investigation.

Purpose: The purpose of this study was to evaluate the effect of UGT1A4 and UGT2B7 polymorphisms on the plasma concentration of lamotrigine in Chinese patients with bipolar disorder.

Methods: A total of 104 patients were included in this study. Steady-state plasma lamotrigine concentrations were determined in each patient after at least 21 days of continuous treatment with a set dose of the drug. Lamotrigine plasma concentrations were ascertained using ultra-performance liquid chromatography. Simultaneously, plasma samples were used for patient genotyping.

Results: The age, sex, BMI, daily lamotrigine dose, plasma lamotrigine concentration, and lamotrigine concentration/dose ratio of patients exhibited significant differences, and these were associated with differences in the genotype [ UGT1A4 -142T>G and UGT2B7 -161C>T ( P  < 0.05)]. Patients with the GG and GT genotypes in UGT1A4 -142T>G had significantly higher lamotrigine concentration/dose values (1.6 ± 1.1 and 1.7 ± 0.5 μg/ml per mg/kg) than those with the TT genotype (1.4 ± 1.1 μg/ml per mg/kg). Likewise, patients with the UGT2B7 -161C>T TT genotype had significantly higher lamotrigine concentration/dose values (1.6 ± 1.1 μg/ml per mg/kg) than those with the CC genotype (1.3 ± 1.3 μg/ml per mg/kg). Multiple linear regression analysis showed that sex, lamotrigine dose, UGT1A4 -142T>G, and UGT2B7 -161C>T were the most important factors influencing lamotrigine pharmacokinetics ( P  < 0.001).

Conclusion: The study results suggest that the UGT1A4 -142T>G and UGT2B7 -161C>T polymorphisms affect lamotrigine plasma concentrations in patients with bipolar disorder.

Objective: Warfarin has a narrow therapeutic window and large variability in dosing that are affected by clinical and genetic factors. To help guide the dosing of warfarin, the Clinical Pharmacogenetics Implementation Consortium has recommended the use of pharmacogenetic algorithms, such as the ones developed by the International Warfarin Pharmacogenetics Consortium (IWPC) and by Gage et al. when genotype information is available.

Methods: In this study, simulations were performed in Chinese cohorts to explore how dosing differences between Western (by IWPC and Gage et al.) and Chinese algorithms (by Miao et al.) would mean in terms of anticoagulation effect in clinical trials. We first tried to replicate a published clinical trial comparing genotype-guided dosing to routine clinical dosing in Chinese patients. We then made simulations where Chinese cohorts received daily doses recommended by Gage, IWPC, and Miao algorithms.

Results: We found that in simulation conditions where dosing specifications were strictly followed, genotype-guided dosing by IWPC and Lenzini formulae was more likely to overshoot the upper limit of the therapeutic window by day 15, and thus may have a lower % time in therapeutic range (%TTR) than that of clinical dosing group. Also, in comparing Gage, IWPC, and Miao algorithms, we found that the Miao dosing cohort has the highest %TTR and the lowest risk of over-anticoagulation by day 28.

Conclusion: In summary, our results confirmed that algorithms developed based on data from local patients may be more suitable for achieving therapeutic international normalized ratio window in Chinese population.

Objectives: We report, for the first time, the distribution of four no-function NAT2 single nucleotide polymorphisms and inferred NAT2 acetylator phenotypes in three indigenous groups (Munduruku, Paiter-Suruí, and Yanomami), living in reservation areas in the Brazilian Amazon.

Methods: Two hundred and seventy-six participants from three indigenous groups (92 for each group) were included and genotyped for four NAT2 polymorphisms (rs1801279, rs1801280, rs1799930, and rs1799931) by the TaqMan system. Minor Allele Frequency (MAF) was determined and NAT2 acetylator phenotypes were inferred.

Results: NAT2 rs1801279G>A was absent in all cohorts; rs1799930G>A was absent in Yanomami and rare (MAF 0.016) in Munduruku and Paiter-Suruí; MAF of rs1801280T>C ranged five-fold (0.092-0.433), and MAF of rs1799931G>A varied between 0.179 and 0.283, among the three groups. The distribution of NAT2 phenotypes differed significantly across cohorts; the prevalence of the slow acetylator phenotype ranged from 16.3% in Yanomami to 33.3% in Munduruku to 48.9% in Paiter-Suruí. This three-fold range of variation is of major clinical relevance because the NAT2 slow phenotype is associated with higher risk of hepatotoxicity with antituberculosis chemotherapy and high incidence rates of tuberculosis and burden of latent infection among Munduruku, Paiter-Surui, and Yanomami peoples. According to the frequency of the NAT2 slow acetylator phenotype, the estimated number of individuals needed to be genotyped to prevent one additional event of hepatotoxicity range from 31 (Munduruku) to 39 (Paiter-Surui) and to 67 (Yanomami).

Conclusion: The rs1801279 polymorphism was not found in any of the cohorts, while the MAF of the other polymorphisms showed significant variation between the cohorts. The difference in the prevalence of the NAT2 slow acetylator phenotype, which is linked to isoniazid-induced hepatotoxicity, was observed in the different study cohorts.

Objective: It is unclear whether renal transplant recipients treated with mycophenolic acid (MPA) who carry the reduced-function allele at polymorphism SLCO1B1 c.521T>C differ from their wild-type peers regarding renal outcomes and tolerability. We aimed to estimate the effect of this polymorphism on the graft function (estimated glomerular filtration rate, eGFR) over the first 12 post-transplant months in patients on MPA-based maintenance immunosuppression.

Methods: In a 12-month observational cohort study, consecutive adult patients were repeatedly assessed for eGFR. The SLCO1B1 c.521C>T variant allele carriers (exposed) and wild-type subjects (controls) were balanced on a range of demographic, medical, and genetic variables at baseline, and eGFR trajectory was estimated with further adjustment for time-varying covariates. A subset of patients were assessed for exposure to MPA 5-7 days after the transplantation.

Results: The adjusted eGFR slopes from day 1 to day 28 (daily), and from day 28 to day 365 (monthly) were practically identical in exposed (n = 86) and control (n = 168) patients [geometric means ratios (GMR) = 0.99, 95% confidence interval (CI) = 0.92-1.06 and GMR = 0.98, 0.94-1.01, respectively]. The rates of adverse renal outcomes and possible MPA-related adverse effects were low, and similar in exposed and controls [rate ratios (RR) = 0.94, 0.49-1.84 and RR = 1.08, 0.74-1.58, respectively]. The pharmacokinetic analysis did not signal meaningful differences regarding exposure to MPA, overall (exposed n = 23, control n = 45), if cotreated with cyclosporine (n = 17 vs. n = 26) or with tacrolimus (n = 8 vs. n = 17).

Conclusions: In patients treated with MPA, variant allele SLCO1B1 c.521T>C appears of no practical relevance regarding the 12-month renal graft function, MPA safety and exposure to MPA at early steady-state.

Objective: Varied expression of drug-metabolizing enzymes (DME) genes dictates the intensity and duration of drug response in cancer treatment. This study aimed to investigate the transcriptional profile of DMEs in tumor microenvironment (TME) at single-cell level and their impact on individual responses to anticancer therapy.

Methods: Over 1.3 million cells from 481 normal/tumor samples across 9 solid cancer types were integrated to profile changes in the expression of DME genes. A ridge regression model based on the PRISM database was constructed to predict the influence of DME gene expression on drug sensitivity.

Results: Distinct expression patterns of DME genes were revealed at single-cell resolution across different cancer types. Several DME genes were highly enriched in epithelial cells (e.g. GPX2, TST and CYP3A5 ) or different TME components (e.g. CYP4F3 in monocytes). Particularly, GPX2 and TST were differentially expressed in epithelial cells from tumor samples compared to those from normal samples. Utilizing the PRISM database, we found that elevated expression of GPX2, CYP3A5 and reduced expression of TST was linked to enhanced sensitivity of particular chemo-drugs (e.g. gemcitabine, daunorubicin, dasatinib, vincristine, paclitaxel and oxaliplatin).

Conclusion: Our findings underscore the varied expression pattern of DME genes in cancer cells and TME components, highlighting their potential as biomarkers for selecting appropriate chemotherapy agents.

Studies have reported overexpression of NAT1 gene for xenobiotic metabolizing arylamine N -acetyltransferase type 1 in estrogen receptor positive breast tumors, and this association has been linked to patient chemoresistance and response to tamoxifen. We probed the expression of NAT1 , using quantitative reverse transcription PCR to screen clinically characterized breast cancer tissue cDNA arrays. Primers detecting all NAT1 alternative transcripts were used, and the protocol and results are reported according to consensus guidelines. The clinical information about 166 tumor samples screened is provided, including tumor stage, estrogen and progesterone receptor status and HER2 expression. NAT1 was found to be significantly ( P  < 0.001) upregulated in hormone receptor positive vs. negative tumors. No correlation was apparent between NAT1 and tumor stage or HER2 expression. Our findings demonstrate a strong correlation between the expression of NAT1 and steroid hormone receptors in breast tumors, supporting its possible utility as a pharmacogenetic biomarker or drug target. Of the two polymorphic NAT genes, NAT1 is the one primarily expressed in breast tissue, and is subjected to regulation by two differential promoters and more than one polyadenylation signal. Hormonal factors may enhance NAT1 gene expression at the transcriptional or epigenetic level, and tamoxifen has additionally been shown to inhibit NAT1 enzymatic activity. The outcome of tamoxifen treatment is also more favorable in patients with NAT1 overexpressing tumors. The study adds to the growing body of evidence implicating NAT1 in breast cancer and its pharmacological treatment.

Objective: This study aims to understand patient and healthcare provider perspectives on the integration and application of pharmacogenetics (PGx) testing in routine clinical practice.

Methods: Two anonymous online surveys were distributed globally for healthcare providers and patients respectively on the Qualtrics platform (version 3.24). The surveys were distributed through social platforms, email, and posters with QR codes from 27 October 2023 to 7 March 2024. The surveys evaluated participant familiarity with PGx, previous experience with PGx testing, perceived implementation challenges, and opinions on point-of-care (PoC) PGx testing devices.

Results: This study collected 78 responses from healthcare providers and 98 responses from patients. The results revealed that 64% of healthcare providers had some level of familiarity with PGx, however, PGx testing in clinical practice was low. The primary challenges identified by healthcare providers included limited access to testing and lack of knowledge on PGx test interpretation. In contrast, 52% of patient respondents were aware of PGx testing, with a significant association between awareness and positive opinions toward PGx. Both healthcare providers and patients recognized the value of PoC PGx testing devices, with 98% of healthcare providers and 71% of patients believing PoC devices would improve the accessibility and implementation of PGx testing. Comparative analysis revealed a statistically significant difference in PGx awareness between healthcare providers and patients, with providers being more informed.

Conclusion: Improved PGx awareness, training, clinical guidelines, and PoC PGx testing devices may help promote the implementation of PGx-guided treatments in routine clinical practice.

Purpose: This study was the first to evaluate the effect of CYP3A5*3 gene polymorphisms on plasma concentration of perampanel (PER) in Chinese pediatric patients with epilepsy.

Methods: We enrolled 98 patients for this investigation. Plasma PER concentrations were measured using liquid chromatography-tandem mass spectrometry. Leftover samples from standard therapeutic drug monitoring were allocated for genotyping analysis. The primary measure of efficacy was the rate of seizure reduction with PER treatment at the final checkup.

Results: The plasma concentration showed a linear correlation with the daily dose taken ( r  = 0.17; P  < 0.05). The ineffective group showed a significantly lower plasma concentration of PER (490.5 ± 297.1 vs. 633.8 ± 305.5 μg/ml; P  = 0.019). For the mean concentration-to-dose (C/D) ratio, the ineffective group showed a significantly lower C/D ratio of PER (3.2 ± 1.7 vs. 3.8 ± 2.0; P  = 0.040). The CYP3A5*3 CC genotype exhibited the highest average plasma concentration of PER at 562.8 ± 293.9 ng/ml, in contrast to the CT and TT genotypes at 421.1 ± 165.6 ng/ml and 260.0 ± 36.1 ng/ml. The mean plasma PER concentration was significantly higher in the adverse events group (540.8 ± 285.6 vs. 433.0 ± 227.2 ng/ml; P  = 0.042).

Conclusion: The CYP3A5*3 gene's genetic polymorphisms influence plasma concentrations of PER in Chinese pediatric patients with epilepsy. Given that both efficacy and potential toxicity are closely tied to plasma PER levels, the CYP3A5*3 genetic genotype should be factored in when prescribing PER to patients with epilepsy.

Objective: The CYP2D6 enzyme is crucial for the metabolism and disposition of a variety of drugs. This study was conducted to examine the relationship between CYP2D6 gene polymorphisms and the response to angiotensin receptor blocker (ARB)-based treatment in patients of Chinese Bai ethnicity with hypertension.

Methods: Seventy-two hypertensive adults from the Chinese Bai ethnic group, exhibiting systolic blood pressure (SBP) ≥ 140 mmHg or diastolic blood pressure (DBP) ≥ 90 mmHg, were recruited. Targeted regional sequencing was utilized to genotype single nucleotide polymorphisms in the CYP2D6 gene, aiming to assess their frequency and to evaluate their influence on the therapeutic efficacy of ARB medications.

Results: Our research identified nine significant CYP2D6 polymorphisms associated with the efficacy of ARB treatment in the Bai hypertensive cohort. Specifically, patients possessing certain mutant genotype at rs111564371 exhibited substantially greater reductions in SBP and DBP, with P -values of 0.021 and 0.016, respectively, compared to those carrying the wild genotype. Additionally, these mutant genotype at rs111564371 and rs112568578 were linked to approximately 20% higher overall efficacy rates and a 10% increased achievement rate relative to the wild genotype.

Conclusion: Our research with the Bai hypertensive group shows that certain CYP2D6 polymorphisms significantly influence ARB treatment outcomes. Mutations at rs111564371 led to better blood pressure control ( P -values: 0.021 for SBP, 0.016 for DBP), improving ARB efficacy by appromixately 20% and increasing treatment goal achievement by 10% over the wild-type genotype.

Statements: Our investigation into CYP2D6 polymorphisms within the Bai hypertensive cohort marks a substantial advancement towards personalized healthcare, underscoring the pivotal influence of genetic constitution on the effectiveness of ARB therapy.