Exploring CYP2D6 polymorphisms and angiotensin receptor blocker response in the Bai hypertensive population

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.

Into a Deeper Understanding of CYP2D6's Role in Risperidone Monotherapy and the Potential Side Effects in Schizophrenia Spectrum Disorders

Schizophrenia spectrum disorders (SSD) are a group of diseases characterized by one or more abnormal features in perception, thought processing and behavior. Patients suffering from SSD are at risk of developing life-threatening complications. Pharmacogenetic studies have shown promising results on personalized treatment of psychosis. In the current study, 103 patients diagnosed with SSD treated with risperidone as antipsychotic monotherapy were enrolled. Socio-demographics and clinical data were recorded, and laboratory tests and genotyping standard procedure for cytochrome P450 (CYP) 2D6*4 were performed. Patients were evaluated by the Positive and Negative Syndrome Scale (PANSS) on admission and at discharge. Based on the reduction in the PANSS total score, subjects were divided into non-responders, partial responders and full responders. Only 11 subjects had a full response to risperidone (10.67%), 53 subjects (51.45%) had a partial response, and 39 participants (37.86%) were non-responders. Patients at first episode psychosis showed significantly higher levels of blood glucose and prolactin levels, while chronic patients showed significantly higher LDL levels. Adverse drug reactions (ADR) such as tremor and stiffness significantly correlated with genetic phenotypes (p = 0.0145). While CYP2D6 showed no impact on treatment response, ADR were significantly more frequent among poor and intermediate metabolizers.

Influence of CYP2C19 and CYP2D6 on side effects of aripiprazole and risperidone: A systematic review

Variability in hepatic cytochrome P450 (CYP) enzymes such as 2C19 and 2D6 may influence side-effect and efficacy outcomes for antipsychotics. Aripiprazole and risperidone are two commonly prescribed antipsychotics, metabolized primarily through CYP2D6. Here, we aimed to provide an overview of the effect of CYP2C19 and CYP2D6 on side-effects of aripiprazole and risperidone, and expand on existing literature by critically examining methodological issues associated with pharmacogenetic studies. A PRISMA compliant search of six electronic databases (Pubmed, PsychInfo, Embase, Central, Web of Science, and Google Scholar) identified pharmacogenetic studies on aripiprazole and risperidone. 2007 publications were first identified, of which 34 were included. Quality of literature was estimated using Newcastle-Ottowa Quality Assessment Scale (NOS) and revised Cochrane Risk of Bias tool. The average NOS score was 5.8 (range: 3-8) for risperidone literature and 5 for aripiprazole (range: 4-6). All RCTs on aripiprazole were rated as high risk of bias, and four out of six for risperidone literature. Study populations ranged from healthy volunteers to inpatient individuals in psychiatric units and included adult and pediatric samples. All n = 34 studies examined CYP2D6. Only one study genotyped for CYP2C19 and found a positive association with neurological side-effects of risperidone. Most studies did not report any relationship between CYP2D6 and any side-effect outcome. Heterogeneity between and within studies limited the ability to synthesize data and draw definitive conclusions. Studies lacked statistical power due to small sample size, selective genotyping methods, and study design. Large-scale randomized trials with multiple measurements, providing robust evidence on this topic, are suggested.

Pharmacogenomics and non-genetic factors affecting drug response in autism spectrum disorder in Thai and other populations: current evidence and future implications

Autism spectrum disorder (ASD) may affect family and social life profoundly. Although there is no selective pharmacotherapy for ASD, the Food and Drug Administration (FDA) has recommended risperidone/aripiprazole to treat the associated symptoms of ASD, such as agitation/irritability. Strong associations of some pharmacokinetic/pharmacodynamic gene variants, e.g., CYP2D6 and DRD2, with risperidone-induced hyperprolactinemia have been found in children with ASD, but such strong genetic associations have not been found directly for aripiprazole in ASD. In addition to pharmacogenomic (PGx) factors, drug-drug interactions (DDIs) and possibly cumulative effects of DDIs and PGx may affect the safety or effectiveness of risperidone/aripiprazole, which should be assessed in future clinical studies in children with ASD. Reimbursement, knowledge, and education of healthcare professionals are the key obstacles preventing the successful implementation of ASD pharmacogenomics into routine clinical practice. The preparation of national and international PGx-based dosing guidelines for risperidone/aripiprazole based on robust evidence may advance precision medicine for ASD.

Regulation of Hepatic Xenosensor Function by HNF4alpha

Nuclear receptors including Aryl hydrocarbon Receptor (AhR), Constitutive Androstane Receptor (CAR), Pregnane X Receptor (PXR), and Peroxisome Proliferator-Activated Receptor-alpha (PPARα) function as xenobiotic sensors. Hepatocyte nuclear factor 4alpha (HNF4α) is a highly conserved orphan nuclear receptor essential for liver function. We tested the hypothesis that HNF4α is essential for function of these four major xenosensors. Wild-type (WT) and hepatocyte-specific HNF4α knockout (HNF4α-KO) mice were treated with the mouse-specific activators of AhR (TCDD, 30 µg/kg), CAR (TCPOBOP, 2.5 µg/g), PXR, (PCN, 100 µg/g), and PPARα (WY-14643, 1 mg/kg). Blood and liver tissue samples were collected to study nuclear receptor activation. TCDD (AhR agonist) treatment did not affect the liver-to-body weight ratio (LW/BW) in either WT or HNF4α-KO mice. Further, TCDD activated AhR in both WT and HNF4-KO mice, confirmed by increase in expression of its target genes. TCPOBOP (CAR agonist) significantly increased the LW/BW ratio and CAR target gene expression in WT mice, but not in HNF4α-KO mice. PCN (a mouse PXR agonist) significantly increased LW/BW ratio in both WT and HNF4α-KO mice however, it failed to induce PXR target genes in HNF4 KO mice. The treatment of WY-14643 (PPARα agonist) increased LW/BW ratio and PPARα target gene expression in WT mice but not in HNF4α-KO mice. Together, these data indicate that the function of CAR, PXR, and PPARα but not of AhR was disrupted in HNF4α-KO mice. These results demonstrate that HNF4α function is critical for the activation of hepatic xenosensors, which are critical for toxicological responses.

Pharmacogenomics in clinical practice to prevent risperidone-induced hyperprolactinemia in autism spectrum disorder

Autism spectrum disorder (ASD) is a global challenge that may disrupts family and social life significantly. There is robust evidence for the association of a pharmacokinetic gene variant (e.g., CYP2D6) with risperidone-induced hyperprolactinemia in ASD. Association of a pharmacodynamic gene variant (e.g., DRD2) with risperidone-induced hyperprolactinemia in ASD is also evident from multiple studies. In addition to genetic factors, dose, duration and drug-drug interactions of risperidone might also increase the serum prolactin level. There are several difficulties, such as reimbursement, knowledge and education of healthcare providers, in implementing risperidone pharmacogenomics into clinical practice. However, preparation of national and international pharmacogenomics-based dosing guidelines of risperidone may advance precision medicine of ASD.

CYP2D6 Genetic Variation and Antipsychotic-Induced Weight Gain: A Systematic Review and Meta-Analysis

BACKGROUND

Antipsychotic-induced weight gain is a contributing factor in the reduced life expectancy reported amongst people with psychotic disorders. CYP2D6 is a liver enzyme involved in the metabolism of many commonly used antipsychotic medications. We investigated if CYP2D6 genetic variation influenced weight or BMI among people taking antipsychotic treatment.

METHODS

We conducted a systematic review and a random effects meta-analysis of publications in Pubmed, Embase, PsychInfo, and CENTRAAL that had BMI and/or weight measurements of patients on long-term antipsychotics by their CYP2D6-defined metabolic groups (poor, intermediate, normal/extensive, and ultra-rapid metabolizers, UMs).

RESULTS

Twelve studies were included in the systematic review. All cohort studies suggested that the presence of reduced-function or non-functional alleles for CYP2D6 was associated with greater antipsychotic-induced weight gain, whereas most cross-sectional studies did not find any significant associations. Seventeen studies were included in the meta-analysis with clinical data of 2,041 patients, including 93 poor metabolizers (PMs), 633 intermediate metabolizers (IMs), 1,272 normal metabolizers (NMs), and 30 UMs. Overall, we did not find associations in any of the comparisons made. The estimated pooled standardized differences for the following comparisons were (i) PM versus NM; weight = -0.07 (95%CI: -0.49 to 0.35, p = 0.74), BMI = 0.40 (95%CI: -0.19 to 0.99, p = 0.19). (ii) IM versus NM; weight = 0.09 (95% CI: -0.04 to 0.22, p = 0.16) and BMI = 0.09 (95% CI: -0.24 to 0.41, p = 0.60). (iii) UM versus EM; weight = 0.01 (95% CI: -0.37 to 0.40, p = 0.94) and BMI = -0.08 (95%CI: -0.57 to 0.42, p = 0.77).

CONCLUSION

Our systematic review of cohort studies suggested that CYP2D6 poor metabolizers have higher BMI than normal metabolizers, but the data of cross-sectional studies and the meta-analysis did not show this association. Although our review and meta-analysis constitutes one of the largest studies with comprehensively genotyped samples, the literature is still limited by small numbers of participants with genetic variants resulting in poor or UMs status. We need further studies with larger numbers of extreme metabolizers to establish its clinical utility in antipsychotic treatment. CYP2D6 is a key gene for personalized prescribing in mental health.

Pharmacogenomic Studies in Intellectual Disabilities and Autism Spectrum Disorder: A Systematic Review

BACKGROUND

Individuals with intellectual disability (ID) and autism spectrum disorder (ASD) often receive psychotropic medications such as antipsychotics and antidepressants to treat aberrant behaviors and mood symptoms, frequently resulting in polypharmacy and drug-related adverse effects. Pharmacogenomic (PGx) studies with ASD and/or ID (ASD/ID) have been scarce despite the promise of optimizing treatment outcomes. We reviewed the literature on PGx studies with antipsychotics and antidepressants (e.g., treatment response and adverse effects) in ASD/ID.

METHODS

We performed a systematic review using MEDLINE, Embase, and PsycINFO, including peer-reviewed original articles in English referring to PGx in the treatment of ASD/ID in any age groups (e.g., treatment response and adverse effects).

RESULTS

A total of 28 PGx studies using mostly candidate gene approaches were identified across age groups. Notably, only 3 studies included adults with ASD/ID while the other 25 studies focused specifically on children/adolescents with ASD/ID. Twelve studies primarily investigated treatment response, of which 5 and 6 studies included patients treated with antipsychotics and antidepressants, respectively. Most interesting results for response were reported for 2 sets of candidate gene studies, namely: (1) The DRD3 Ser9Gly (rs6280) polymorphism was examined in patients treated with risperidone in 3 studies, 2 of which reported an association with risperidone treatment response and (2) the SLC6A4 5-HTTLPR polymorphism and treatment response to antidepressants which was investigated in 4 studies, 3 of which reported significant associations. In regard to side effects, 9 of 15 studies focused on hyperprolactinemia in patients treated with risperidone. Among them, 7 and 5 studies examined the impact of CYP2D6 and DRD2 Taq1A polymorphisms, respectively, yielding mostly negative study findings.

CONCLUSIONS

There is limited data available on PGx in individuals with ASD/ID and in particular in adults. Given the potential for PGx testing in improving treatment outcomes, additional PGx studies for psychotropic treatment in ASD/ID across age groups are warranted.

CYP2D6 phenotype and ABCB1 haplotypes are associated with antipsychotic safety in adolescents experiencing acute psychotic episodes

OBJECTIVES

To identify possible associations of CYP2D6, CYP3A4/5, and ABCB1 gene polymorphisms with the efficacy and safety of antipsychotics in adolescents with acute psychotic episodes.

METHODS

We examined the associations of pharmacogenetic factors with the efficacy and safety of antipsychotics in 101 adolescents with acute psychotic episodes. The diagnosis on admission was "Brief psychotic disorder" (F23.0-23.9 by ICD-10). All patients were administered antipsychotics for 14 days. Treatment efficacy and safety were assessed using the PANSS, CGAS, CGI-S(I), UKU SERS, BARS, and SAS scales. Pharmacokinetic genotyping was performed for the CYP2D6*4, *10, ABCB1 1236C>T, 2677G>T, and 3435C>T genes.

RESULTS

CYP2D6 intermediate metabolisers had "Micturition disturbances" more often than extensive metabolisers (24.2 vs. 7.4%; p=0.026). "Wild" homozygote ABCB1 3435C>T CC was associated with more prominent akathisia. Haplotype analysis of three ABCB1 polymorphisms revealed that the "wild" alleles "C-G-C" (ABCB1 1236-2677-3435) were associated with higher risk of "Reduced salivation" (OR=2.95; 95% CI=1.35-6.45; p=0.0078).

CONCLUSIONS

CYP2D6 intermediate metabolism was associated with the risk of urinary difficulties under treatment with antipsychotics. We found that "wild" homozygotes ABCB1 1236C>T, 2677G>T, and 3435C>T were predictors of adverse drug effects caused by treatment with antipsychotics.

CYP2D6 phenotype and ABCB1 haplotypes are associated with antipsychotic safety in adolescents experiencing acute psychotic episodes

OBJECTIVES

To identify possible associations of CYP2D6, CYP3A4/5, and ABCB1 gene polymorphisms with the efficacy and safety of antipsychotics in adolescents with acute psychotic episodes.

METHODS

We examined the associations of pharmacogenetic factors with the efficacy and safety of antipsychotics in 101 adolescents with acute psychotic episodes. The diagnosis on admission was "Brief psychotic disorder" (F23.0-23.9 by ICD-10). All patients were administered antipsychotics for 14 days. Treatment efficacy and safety were assessed using the PANSS, CGAS, CGI-S(I), UKU SERS, BARS, and SAS scales. Pharmacokinetic genotyping was performed for the CYP2D6*4, *10, ABCB1 1236C>T, 2677G>T, and 3435C>T genes.

RESULTS

CYP2D6 intermediate metabolisers had "Micturition disturbances" more often than extensive metabolisers (24.2 vs. 7.4%; p=0.026). "Wild" homozygote ABCB1 3435C>T CC was associated with more prominent akathisia. Haplotype analysis of three ABCB1 polymorphisms revealed that the "wild" alleles "C-G-C" (ABCB1 1236-2677-3435) were associated with higher risk of "Reduced salivation" (OR=2.95; 95% CI=1.35-6.45; p=0.0078).

CONCLUSIONS

CYP2D6 intermediate metabolism was associated with the risk of urinary difficulties under treatment with antipsychotics. We found that "wild" homozygotes ABCB1 1236C>T, 2677G>T, and 3435C>T were predictors of adverse drug effects caused by treatment with antipsychotics.

Evidence for Pharmacogenomic Effects on Risperidone Outcomes in Pediatrics

OBJECTIVE

To determine the association between genetic variants reported to affect risperidone and adverse events (AEs) in children and adolescents.

METHODS

Individuals aged 18 years or younger with ≥4 weeks of risperidone exposure in a deidentified DNA biobank were included. The primary outcome was AE frequency as a function of genotype. Individuals were classified according to metabolizer status for CYP2D6, CYP3A4, and CYP3A5; wild type, heterozygote, or homozygote for specific single nucleotide variants for DRD2, DRD3, HTR2A, and HTR2C; and wild type versus nonwild type for multiple uncommon variants in ABCG2, ABCB1, and HTR2C. Tests of association of each classification to AEs were performed using a Fisher exact test and logistic regression, and statistically significant classifications were included in a final logistic regression.

RESULTS

The final cohort included 257 individuals. AEs were more common in CYP2D6 poor/intermediate metabolizers (PMs/IMs) than normal/rapid/ultrarapid metabolizers (NMs/RMs/UMs) in univariate and multivariate analysis. HTR2A-rs6311 heterozygotes and homozygotes had fewer AEs than wild types in logistic regression but not in univariate analysis. In the final multivariable model adjusting for age, race, sex, and risperidone dose, AEs were associated with CYP2D6 (adjusted odds ratio [AOR] 2.6, 95% CI 1.1-5.5, for PMs/IMs vs. NMs/RMs/UMs) and HTR2A-rs6311 (AOR 0.6, 95% CI 0.4-0.9, for each variant allele), both consistent with previous studies.

CONCLUSION

Children and adolescents who are CYP2D6 PMs/IMs may have an increased risk for risperidone AEs. Of the genes and variants studied, only CYP2D6 has consistent association and sufficient data for clinical use, whereas HTR2A-rs6311 has limited data and requires further study.

The Long Noncoding RNA Hepatocyte Nuclear Factor 4α Antisense RNA 1 Negatively Regulates Cytochrome P450 Enzymes in Huh7 Cells via Histone Modifications

The maintenance of homeostasis of cytochromes P450 enzymes (P450s) under both physiologic and xenobiotic exposure conditions is ensured by the action of positive and negative regulators. In the current study, the hepatocyte nuclear factor 4α (HNF4A) antisense RNA 1 (HNF4A-AS1), an antisense long noncoding RNA of HNF4A, was found to be a negative regulator of the basal and rifampicin (RIF)-induced expression of nuclear receptors and downstream P450s. In Huh7 cells, knockdown of HNF4A-AS1 resulted in elevated expression of HNF4A, pregnane X receptor (PXR), and P450s (including CYP3A4) under both basal and RIF-induced conditions. Conversely, overexpression of HNF4A-AS1 led to decreased basal expression of constitutive androstane receptor, aryl hydrocarbon receptor, PXR, and all studied P450s. Of note, significantly diminished induction levels of PXR and CYP1A2, 2C8, 2C19, and 3A4 by RIF were also observed in HNF4A-AS1 plasmid-transfected Huh7 cells. Moreover, the negative feedback of HNF4A on HNF4A-AS1-mediated gene expression was validated using a loss-of-function experiment in this study. Strikingly, our data showed that increased enrichment levels of histone 3 lysine 4 trimethylation and HNF4A in the CYP3A4 promoter contribute to the elevated CYP3A4 expression after HNF4A-AS1 knockdown. Overall, the current study reveals that histone modifications contribute to the negative regulation of nuclear receptors and P450s by HNF4A-AS1 in basal and drug-induced levels. SIGNIFICANCE STATEMENT: Utilizing loss-of-function and gain-of-function experiments, the current study systematically investigated the negative regulation of HNF4A-AS1 on the expression of nuclear receptors (including HNF4A, constitutive androstane receptor, aryl hydrocarbon receptor, and pregnane X receptor) and P450s (including CYP1A2, 2E1, 2B6, 2D6, 2C8, 2C9, 2C19, and 3A4) in both basal and rifampicin-induced levels in Huh7 cells. Notably, this study is the first to reveal the contribution of histone modification to the HNF4A-AS1-mediated expression of CYP3A4 in Huh7 cells.

CYP2D6 and Antipsychotic Treatment Outcomes in Children and Youth: A Systematic Review

Objective: To systematically review the impact of CYP2D6 genetic variation on antipsychotic pharmacokinetics, efficacy, and adverse drug reactions among children and youth. Method: The published literature was systematically searched in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations and critically evaluated using standardized tools and consensus criteria. Results: A total of 20 eligible studies comprising 1078 children and youth were evaluated. The included studies were of fair to moderate quality and included mostly males, individuals of European ancestry, and those treated with risperidone. CYP2D6 poor metabolizers (PMs) were consistently shown to have increased concentrations of risperidone relative to normal metabolizers (NMs). PMs were also consistently shown to have a greater propensity to experience antipsychotic (primarily risperidone) associated adverse drug reactions relative to NMs. However, robust evidence for an association between CYP2D6 and efficacy was less apparent. Conclusion and Clinical Significance: The current knowledge base suggests that CYP2D6 genetic variation has an appreciable impact on antipsychotic pharmacokinetics and the propensity for adverse drug reactions, particularly among children receiving risperidone treatment. However, several limitations with the current literature (e.g., sample sizes, study design, sample heterogeneity) should be addressed in future studies. Assuming that future studies support the link between CYP2D6 genetic variation and antipsychotic outcomes, we would anticipate an increase in the implementation of CYP2D6-guided antipsychotic drug selection and dose optimization in child and adolescent psychiatric services.

Peripheral blood neurotrophic factor levels in children with autism spectrum disorder: a meta-analysis

Increasing evidence suggests that abnormal regulation of neurotrophic factors is involved in the etiology and pathogenesis of Autism Spectrum Disorder (ASD). However, clinical data on neurotrophic factor levels in children with ASD were inconsistent. Therefore, we performed a systematic review of peripheral blood neurotrophic factors levels in children with ASD, and quantitatively summarized the clinical data of peripheral blood neurotrophic factors in ASD children and healthy controls. A systematic search of PubMed and Web of Science identified 31 studies with 2627 ASD children and 4418 healthy controls to be included in the meta-analysis. The results of random effect meta-analysis showed that the peripheral blood levels of brain-derived neurotrophic factor (Hedges’ g = 0.302; 95% CI = 0.014 to 0.591; P = 0.040) , nerve growth factor (Hedges’ g = 0.395; 95% CI = 0.104 to 0.686; P = 0.008) and vascular endothelial growth factor (VEGF) (Hedges’ g = 0.097; 95% CI = 0.018 to 0.175; P = 0.016) in children with ASD were significantly higher than that of healthy controls, whereas blood neurotrophin-3 (Hedges’ g =  − 0.795; 95% CI =  − 1.723 to 0.134; P = 0.093) and neurotrophin-4 (Hedges’ g = 0.182; 95% CI =  − 0.285 to 0.650; P = 0.445) levels did not show significant differences between cases and controls. Taken together, these results clarified circulating neurotrophic factor profile in children with ASD, strengthening clinical evidence of neurotrophic factor aberrations in children with ASD.

A Machine Learning Model to Predict Risperidone Active Moiety Concentration Based on Initial Therapeutic Drug Monitoring

Risperidone is an efficacious second-generation antipsychotic (SGA) to treat a wide spectrum of psychiatric diseases, whereas its active moiety (risperidone and 9-hydroxyrisperidone) concentration without a therapeutic reference range may increase the risk of adverse drug reactions. We aimed to establish a prediction model of risperidone active moiety concentration in the next therapeutic drug monitoring (TDM) based on the initial TDM information using machine learning methods. A total of 983 patients treated with risperidone between May 2017 and May 2018 in Beijing Anding Hospital were collected as the data set. Sixteen predictors (the initial TDM value, dosage, age, WBC, PLT, BUN, weight, BMI, prolactin, ALT, MECT, Cr, AST, Ccr, TDM interval, and RBC) were screened from 26 variables through univariate analysis (p < 0.05) and XGBoost (importance score >0). Ten algorithms (XGBoost, LightGBM, CatBoost, AdaBoost, Random Forest, support vector machine, lasso regression, ridge regression, linear regression, and k-nearest neighbor) compared the model performance, and ultimately, XGBoost was chosen to establish the prediction model. A cohort of 210 patients treated with risperidone between March 1, 2019, and May 31, 2019, in Beijing Anding Hospital was used to validate the model. Finally, the prediction model was evaluated, obtaining R ² (0.512 in test cohort; 0.374 in validation cohort), MAE (10.97 in test cohort; 12.07 in validation cohort), MSE (198.55 in test cohort; 324.15 in validation cohort), RMSE (14.09 in test cohort; 18.00 in validation cohort), and accuracy of the predicted TDM within ±30% of the actual TDM (54.82% in test cohort; 60.95% in validation cohort). The prediction model has promising performance to facilitate rational risperidone regimen on an individualized level and provide reference for other antipsychotic drugs' risk prediction.

Pharmacogenetics of antipsychotics: Clinical utility and implementation

Decades of research have produced extensive evidence of the contribution of genetic factors to the efficacy and toxicity of antipsychotics. Numerous genetic variants in genes controlling drug availability or involved in antipsychotic processes have been linked to treatment variability. The complex mechanism of action and multitarget profile of most antipsychotic drugs hinder the identification of pharmacogenetic markers of clinical value. Nevertheless, the validity of associations between variants in CYP1A2, CYP2D6, CYP2C19, ABCB1, DRD2, DRD3, HTR2A, HTR2C, BDNF, COMT, MC4R genes and antipsychotic response has been confirmed in independent candidate gene studies. Genome wide pharmacogenomic studies have proven the role of the glutamatergic pathway in mediating antipsychotic activity and have reported novel associations with antipsychotic response. However, only a limited number of the findings, mainly functional variants of CYP metabolic enzymes, have been shown to be of clinical utility and translated into useful pharmacogenetic markers. Based on the currently available information, actionable pharmacogenetics should be reduced to antipsychotics' dose adjustment according to the genetically predicted metabolic status (CYPs' profile) of the patient. Growing evidence suggests that such interventions will reduce antipsychotics' side-effects and increase treatment safety. Despite this evidence, the use of pharmacogenetics in psychiatric wards is minimal. Hopefully, further evidence on the clinical and economic benefits, the development of clinical protocols based on pharmacogenetic information, and improved and cheaper genetic testing will increase the implementation of pharmacogenetic guided prescription in clinical settings.

Risperidone-Induced Obesity in Children and Adolescents With Autism Spectrum Disorder: Genetic and Clinical Risk Factors

Aims: Obesity is a significant problem for patients taking atypical antipsychotics. There were two aims of our study. The first aim was to compare the prevalence of overweight and obesity between children and adolescents with autism spectrum disorder (ASD) treated with risperidone with the general pediatric population. The second aim was to investigate the association of the HTR2C -759C>T, ABCB1 1236C>T, ABCB1 2677G>T/A, and ABCB1 3435C>T polymorphisms with risperidone-induced overweight and obesity in children and adolescents with ASD. Methods: Body weight and height were measured in 134 subjects. Overweight and obesity in children and adolescents were classified using the International Obesity Task Force (IOTF) criteria. Genotyping was performed by TaqMan real-time polymerase chain reaction (PCR). Results: Our study found that the prevalence of overweight and obesity was significantly higher in children and adolescents with ASD treated with risperidone compared with healthy individuals (p = 0.01 and p = 0.002). The genetic polymorphisms of HTR2C -759C>T, ABCB1 1236C>T, ABCB1 2677G>T/A, and ABCB1 3435C>T were not associated with overweight/obesity in children and adolescents with ASD treated with risperidone after adjustment for multiple comparisons by the method of Bonferroni. Additionally, haplotype analysis revealed that there was no significant association between ABCB1 3435T-2677T/A-1236T haplotype and overweight/obesity. In multivariate logistic regression, after adjustment by the Bonferroni correction, there was only the duration of risperidone treatment that was significantly associated with overweight/obesity in children and adolescents with ASD. Conclusions: The findings suggest that children and adolescents with ASD treated with risperidone are at a higher risk of obesity, especially patients with extended treatment with risperidone. For the pharmacogenetic factors, -759C>T polymorphism of HTR2C gene and 1236C>T, 2677G>T/A, and 3435C>T polymorphisms of ABCB1 gene were not likely to be associated with the susceptibility to overweight/obesity in children and adolescents treated with risperidone. Due to the small sample size, further studies with a larger independent group are needed to confirm these findings.

Pharmacogenetics of antipsychotics in adolescents with acute psychotic episode during first 14 days after admission: effectiveness and safety evaluation

Objectives Prediction of the antipsychotic's effectiveness is a relevant topic in the field of personalized medicine. Methods The research design of this study is a prospective observation with posthoc analysis of associations of genetic polymorphisms with safety parameters and effectiveness of antipsychotic therapy. We observed 53 adolescents with an acute psychotic episode which were prescribed antipsychotics for 14 days. We evaluated the effectiveness of antipsychotics with the Positive and Negative Symptoms Scale and the safety with the UKU Side Effects Rating Scale, Simpson-Angus Scale, and Barnes Akathisia rating scale. We genotyped CYP3A4*22 (rs2740574), CYP3A5*3 (6986A>G, rs7767746), CYP2D6*4, *9, *10 (rs3892097, rs1065852), ABCB1 1236C>T (rs1128503), 2677G>T/A (rs2032582), 3435C>T (rs1045642), DRD2 (rs1800497), DRD4 (rs1800955), HTR2A (rs6313) by the real-time polymerase chain reaction method. Results We found significantly more frequent "increased dream activity" between CYP2D6 intermediate metabolizers and normal metabolizers (54 vs. 22%; p=0.043). The «increased duration of sleep» was more often observed in homozygotes TT of ABCB1 2677G>T/A (50 vs. 15.8%, p=0.006) and TT of 3435C>T (41.7 vs. 8.2%, p=0.007). Conclusions We found that CYP2D6 and ABCB1 polymorphisms were associated with the safety of antipsychotics in adolescents with an acute psychotic episode.

Nrf2 Antioxidative System is Involved in Cytochrome P450 Gene Expression and Activity: A Delay in Pentobarbital Metabolism in Nrf2-Deficient Mice

NF-E2-related factor 2 (Nrf2) is a transcriptional regulator of biologic defense proteins, such as antioxidant proteins and phase II detoxification enzymes. Cytochrome P450 (P450) enzymes have been shown to regulate phase I metabolism of various drugs and are partially regulated by Nrf2; however, the influence of Nrf2 on drug pharmacokinetics is not known. Here, we showed that Nrf2 depletion prolonged the effect of pentobarbital, a sleep-promoting drug. Pretreatment with phenobarbital, a P450 inducer, shortens the sleeping time associated with pentobarbital-induced sedation in wild-type (WT) mice; however, this effect was not observed in Nrf2^-/- mice. Furthermore, the blood pentobarbital concentration was higher in Nrf2^-/- mice than in WT mice at 30-60 minutes, and the phenobarbital-induced enhancement of its clearance was attenuated in Nrf2^-/- mice compared with WT mice. Total P450 content was decreased in Nrf2^-/- mouse livers, and the phenobarbital-induced increase in P450 content was lower in Nrf2^-/- mice than WT mice. Cyp1a2, Cyp2a5, Cyp2c29, and Cyp2e1 gene expression levels under physiologic conditions and Cyp1a2, Cyp2a5, and Cyp2b10 gene expression levels under phenobarbital-treated conditions were lower in Nrf2^-/- mice compared with WT mice. Additionally, pentobarbital metabolism in liver microsomes was attenuated by Nrf2 depletion. Taken together, these findings suggested that Nrf2 influenced pentobarbital pharmacokinetics through the regulation of drug metabolism and P450 gene expression. Thus, Nrf2-mediated regulation of P450 may contribute to the biologic defense against increased reactive oxygen species production. SIGNIFICANCE STATEMENT: NF-E2-related factor 2 (Nrf2) plays a critical role in the cellular defense against oxidative stress. Nrf2^-/- mice with reduced ability to eliminate reactive oxygen species (ROS) showed a significant delay in emergence from pentobarbital-induced sleep, which was associated with decreased P450 activities and gene expression. Our findings provide that Nrf2 dysfunction or ROS that exceed a threshold level of the eliminating ability of the Nrf2 system may reduce P450 activity.

Menaquinone-4 Accelerates Calcification of Human Aortic Valve Interstitial Cells in High-Phosphate Medium through PXR

Recently, we confirmed that in human aortic valve interstitial cells (HAVICs) isolated from patients with aortic valve stenosis (AVS), calcification is induced in high inorganic phosphate (high-Pi) medium by warfarin (WFN). Because WFN is known as a vitamin K antagonist, reducing the formation of blood clots by vitamin K cycle, we hypothesized that vitamin K regulates WFN-induced HAVIC calcification. Here, we sought to determine whether WFN-induced HAVIC calcification in high-Pi medium is inhibited by menaquinone-4 (MK-4), the most common form of vitamin K₂ in animals. HAVICs obtained from patients with AVS were cultured in α-modified Eagle's medium containing 10% FBS, and when the cells reached 80%-90% confluency, they were further cultured in the presence or absence of MK-4 and WFN for 7 days in high-Pi medium (3.2 mM Pi). Intriguingly, in high-Pi medium, MK-4 dose-dependently accelerated WFN-induced HAVIC calcification and also accelerated the calcification when used alone (at 10 nM). Furthermore, MK-4 enhanced alkaline phosphatase (ALP) activity in HAVICs, and 7 days of MK-4 treatment markedly upregulated the gene expression of the calcification marker bone morphogenetic protein 2 (BMP2). Notably, MK-4-induced calcification was potently suppressed by two pregnane X receptor (PXR) inhibitors, ketoconazole and coumestrol; conversely, PXR activity was weakly increased, but in a statistically significant and dose-dependent manner, by MK-4. Lastly, in physiologic-Pi medium, MK-4 increased BMP2 gene expression and accelerated excess BMP2 (30 ng/ml)-induced HAVIC calcification. These results suggest that MK-4, namely vitamin K₂, accelerates calcification of HAVICs from patients with AVS like WFN via PXR-BMP2-ALP pathway. SIGNIFICANCE STATEMENT: For aortic valve stenosis (AVS) induced by irreversible valve calcification, the most effective treatment is surgical aortic or transcatheter aortic valve replacement, but ∼20% of patients are deemed unsuitable because of its invasiveness. For effective drug treatment strategies for AVS, the mechanisms underlying aortic valve calcification must be elucidated. Here, we show that menaquinone-4 accelerates warfarin-induced calcification of AVS-patient human aortic valve interstitial cells in high inorganic phosphate medium; this effect is mediated by pregnane X receptor-bone morphogenetic protein 2-alkaline phosphatase signaling, which could be targeted for novel drug development.

Association between polymorphisms of LEP, LEPR, DRD2, HTR2A and HTR2C genes and risperidone- or clozapine-induced hyperglycemia

Objective

To determine whether genetic polymorphisms related to pharmacodynamics with metabolic adverse effects, namely leptin promoter (LEP) rs7799039, leptin receptor rs1137101, dopamine D2 rs4436578, serotonin 5-HT2A rs6313, and serotonin 5-HT2C rs518147 and rs12836771, are associated with hyperglycemia induced by risperidone or clozapine in adult Thai patients with psychosis.

Methods

A total of 180 patients treated with risperidone-based (n=130) or clozapine-based (n=50) regimens were included in this study. Blood samples were analyzed for genotyping of the candidate genes and biochemical testing. Genotyping was performed by conducting a TaqMan real-time polymerase chain reaction-based analysis.

Results

The prevalence of hyperglycemia was higher in patients receiving clozapine (64.0%) than in those receiving risperidone (30.8%). Among the candidate genes, only the LEP rs7799039 polymorphism demonstrated a significant association with hyperglycemia (χ²=9.879, P=0.008) in patients treated with risperidone; patients with the AA genotype had the highest risk (41.1%), followed by those with AG (20.8%) and GG (0%) genotypes. Using the recessive genetic model (AA vs AG + GG), the odds ratio and 95% CI were 3.28 and 1.44 −7.50, respectively. None of the genes were associated with hyperglycemia in patients treated with clozapine. A binary logistic regression revealed that the LEP rs7799039 polymorphism demonstrated a significant association with hyperglycemia, independent of body-mass index (BMI) in patients receiving risperidone; the odds ratio (95% CI) was 3.188 (1.399–7.262), P=0.006. By contrast, none of the pharmacodynamic genetic factors, except for BMI, were significantly associated with hyperglycemia in patients receiving clozapine.

Conclusion

The risk of type 2 diabetes mellitus is associated with the LEP rs7799039 polymorphism in Thai adults receiving risperidone but not in those receiving clozapine. Clarifying underlying mechanisms and risk of hyperglycemia provides an opportunity to prevent impaired glucose metabolism in patients receiving risperidone or clozapine.