Association of Oseltamivir Activation with Gender and Carboxylesterase 1 Genetic Polymorphisms

Oseltamivir, an inactive anti‐influenza virus prodrug, is activated (hydrolysed) in vivo by carboxylesterase 1 (CES1) to its active metabolite oseltamivir carboxylate. CES1 functions are significantly associated with certain CES1 genetic variants and some non‐genetic factors. The purpose of this study was to investigate the effect of gender and several CES1 genetic polymorphisms on oseltamivir activation using a large set of individual human liver samples. CES1‐mediated oseltamivir hydrolysis and CES1 genotypes, including the G143E (rs71647871), rs2244613, rs8192935, the ‐816A>C (rs3785161) and the CES1P1/CES1P1VAR, were determined in 104 individual human livers. The results showed that hepatic CES1 protein expression in females was 17.3% higher than that in males (p = 0.039), while oseltamivir activation rate in the livers from female donors was 27.8% higher than that from males (p = 0.076). As for CES1 genetic polymorphisms, neither CES1 protein expression nor CES1 activity on oseltamivir activation was significantly associated with the rs2244613, rs8192935, ‐816A>C or CES1P1/CES1P1VAR genotypes. However, oseltamivir hydrolysis in the livers with the genotype 143G/E was approximately 40% of that with the 143G/G genotype (0.7 ± 0.2 versus 1.8 ± 1.1 nmole/mg protein/min, p = 0.005). In summary, the results suggest that hepatic oseltamivir activation appears to be more efficient in females than that in males, and the activation can be impaired by functional CES1 variants, such as the G143E. However, clinical implication of CES1 gender differences and pharmacogenetics in oseltamivir pharmacotherapy warrants further investigations.     

Antagonizing Effects of Soybean Isoflavones on β-Amyloid Peptide-Induced Oxidative Damage in Neuron Mitochondria of Rats

Soybean isoflavone (SIF) has been demonstrated to have neuroprotective effects induced by β‐amyloid peptides (Aβ) through suppressing oxidative stress; however, the explicit mechanisms still remain uncovered. In the present study, 32 Wistar rats were randomly divided into four groups: an Aβ1‐42‐treated group, a SIF + Aβ1‐42 group, a SIF‐treated group and a control group. We measured the protein content of 8‐hydroxydeoxyguanosine (8‐OhdG) and mRNA expression of 8‐oxoguanine DNA glycosylase (OGG1). The protein expression of OGG1, Bcl‐xl, Bad, beta subunit of ATP synthase (ATPB) and pyruvate dehydrogenase (PDH) in brain was also measured. The results showed that the level of 8‐OHdG in both SIF groups was significantly decreased compared to the Aβ1‐42‐treated group (p < 0.05), while the mRNA and protein expression of OGG1 in the SIF + Aβ1‐42 groups were up‐regulated compared with the Aβ1‐42‐treated groups (p < 0.05). The expression of Bcl‐xl was up‐regulated in the SIF‐treated group compared with the Aβ1‐42‐treated groups (p < 0.05), while the expression of Bad was down‐regulated in the two SIF‐treated groups (p < 0.05). Aβ1‐42 significantly down‐regulated the expression of ATPase and PDH proteins compared with the control group (p < 0.05). SIF reversed the down‐regulation effects on the mitochondrial energy metabolic enzymes induced by Aβ1‐42 (p < 0.05) in the rats. These results suggest that SIF alleviate the oxidative stress in neurons and mitochondria of rat brains mediated by Aβ1‐42, and these protective effects might be associated with the regulation of OGG1, Bad, Bcl‐xl, ATPB and PDH.     

Salbutamol‐induced Decrease in Augmentation Index is Related to the Parallel Increase in Heart Rate

The change in augmentation index following salbutamol inhalation has been applied to evaluate endothelial function. We examined the contribution of salbutamol‐induced increase in heart rate to the observed decrease in augmentation index. Haemodynamics were recorded using whole‐body impedance cardiography and continuous pulse wave analysis from tonometric radial blood pressure. All subjects (n = 335, mean age 46, body mass index 26, 48% men) were without medications with cardiovascular influences. The effects of salbutamol inhalation (0.4 mg) versus the endothelium‐independent agent nitroglycerin resoriblet (0.25 mg) were examined during passive head‐up tilt, as the haemodynamic influences of these compounds depend on body position. Salbutamol decreased augmentation index by ~3‐4% units in supine and upright positions. Although salbutamol moderately increased cardiac index (+4.5%) and decreased systemic vascular resistance (?8.5%), the significant haemodynamic explanatory factors for decreased augmentation index in multivariate analysis were increased supine heart rate, and increased upright heart rate and decreased ejection duration (p < 0.001 for all, r² = 0.36–0.37). Sublingual nitroglycerin decreased supine and upright augmentation index by ~15% units and ~23% units, respectively. The haemodynamic explanatory factors for these changes in multivariate analysis were increased heart rate, reduced ejection duration and reduced systemic vascular resistance (p ≤ 0.021 for all, r² = 0.22–0.34). In conclusion, the lowering influence of salbutamol on augmentation index may be largely explained by increased heart rate, suggesting that this effect may not predominantly reflect endothelial function.     

CYP2C19*17 increases clopidogrel‐mediated platelet inhibition but does not alter the pharmacokinetics of the active metabolite of clopidogrel

The aim of the present study was to determine the impact of CYP2C19*17 on the pharmacokinetics and pharmacodynamics of the active metabolite of clopidogrel and the pharmacokinetics of proguanil. Thus, we conducted an open‐label two‐phase cross‐over study in 31 healthy male volunteers (11 CYP2C19*1/*1, 11 CYP2C19*1/*17 and nine CYP2C19*17/*17). In Phase A, the pharmacokinetics of the derivatized active metabolite of clopidogrel (CAMD) and platelet function were determined after administration of a single oral dose of 600 mg clopidogrel (Plavix; Sanofi‐Avensis, Horsholm, Denmark). In Phase B, the pharmacokinetics of proguanil and its metabolites cycloguanil and 4‐chlorphenylbiguanide (4‐CPB) were determined in 29 of 31 subjects after a single oral dose of 200 mg proguanil given as the combination drug Malarone (GlaxoSmithKline Pharma, Brondby, Denmark). Significant correlations were found between the area under the time–concentration curve (AUC_0–∞) of CAMD and both the absolute ADP‐induced P2Y₁₂ receptor‐activated platelet aggregation (r = ?0.60, P = 0.0007) and the percentage inhibition of aggregation (r = 0.59, P = 0.0009). In addition, the CYP2C19*17/*17 and CYP2C19*1/*17 genotype groups had significantly higher percentage inhibition of platelet aggregation compared with the CYP2C19*1/*1 subjects (geometric mean percentage inhibition of 84%, 73% and 63%, respectively; P = 0.014). Neither the absolute ADP‐induced P2Y₁₂ receptor‐activated platelet aggregation, exposure to CAMD nor the pharmacokinetic parameters of proguanil, cycloguanil and 4‐CPB exhibited any significant differences among the genotype groups. In conclusion, carriers of CYP2C19*17 exhibit higher percentage inhibition of platelet aggregation, but do not have significantly lower absolute P2Y₁₂ receptor‐activated platelet aggregation or higher exposure to the active metabolite after a single oral administration of 600 mg clopidogrel.     

Identification of Damaging nsSNVs in HumanERCC2 Gene

The hERCC2 gene is an important DNA repair molecule for initiating Cutaneous melanoma (CM). Therefore, it is advisable to study the possible functional SNVs in hERCC2. To achieve this goal, we collected total 2, 253 SNVs in hERCC2from the EMBL website, of which 303 are non‐synonymous single nucleotide variants (nsSNVs). Then, SIFT and PolyPhen were used to predict the damaging nsSNVs, and four nsSNVs (rs368866996, rs377739017, rs370819591, and rs121913022) were suggested to be damaging mutations. Since I‐Mutant2.0 showed a decrease in stability for the mutants containing each of the four nsSNVs, a 3D protein structure was modeled. Based on the comparison of the energy after minimization, RMSD and stabilizing residues between the native and mutant proteins' structure, rs121913022 was proposed to be the most damaging variant among the nsSNVs in hERCC2 gene by decreasing the stability of protein. The mutant G713R of hERCC2 protein caused by rs121913022 was found to have less expression level than native hERCC2 protein in melanoma cells. These results suggest that rs121913022 may have potentially important clinical and drug target implications.     

The Effect of ABCB1 C3435T Polymorphism on Cyclosporine Dose Requirements in Kidney Transplant Recipients: A Meta‐Analysis

Cyclosporine A (CsA) is a substrate of the multi‐drug efflux pump P‐glycoprotein (P‐gp) encoded by ABCB1. Among the various single nucleotide polymorphisms (SNPs) of ABCB1, C3435T has been extensively investigated to determine the relationship with the pharmacokinetics of CsA. However, the results are controversial. This meta‐analysis was designed to evaluate the influence of C3435T SNP on the dose‐adjusted trough (C₀/D) and peak (C_max/D) concentrations of CsA. Based on a literature search of four authoritative databases, 13 studies since 2001 concerning 1293 kidney transplant recipients were included. The results indicated a significant difference of C₀/D and C_max/D between 3435CC and 3435TT genotype carriers (weighted mean difference (WMD) of C₀/D: 4.18 (ng ml^?1)/(mg kg^?1), 95% CIs: 1.00–7.37, p = 0.01; WMD of C_max/D: 20.85 (ng ml^?1)/(mg kg^?1), 95% CIs: 2.25–39.46, p = 0.03). Subgroup analysis by ethnicity demonstrated that C₀/D was lower in Asian CC versus TT genotype carriers (WMD = 10.32 (ng ml^?1)/(mg kg^?1), 95% CIs: 4.78–15.85, p = 0.0003) but did not vary by genotype for Caucasian recipients. Moreover, significant variation of C₀/D was found at 1 week and 1–3 months after transplantation between CC and TT genotype carriers. Therefore, this meta‐analysis showed a correlation between ABCB1 C3435T polymorphism and the dose‐adjusted concentration of CsA. Patients with 3435CC genotype will require a higher dose of CsA to achieve target therapeutic concentrations when compared with 3435TT carriers after kidney transplantation, especially in the Asian population and especially during the early and middle time periods after transplantation.     

The influence of ABCB1 and P2Y12 genetic variants on clinical outcomes in Chinese intracranial artery stenosis patients

For intracranial artery stenosis patients, high inter‐individual variability in response to antiplatelet drug therapy results in recurrent ischaemic events. We aimed to evaluate the association of drug‐related genetic polymorphisms with adverse clinical outcomes. We consecutively enrolled 157 patients receiving dual‐antiplatelet therapy (aspirin plus clopidogrel), and adverse clinical events occurred in 10 patients during the 1 year follow‐up. The P2Y12 polymorphisms (rs9859538 and rs10935842) were associated with increased likelihood of relapse events (OR = 2.934, 95% CI = 1.022‐8.425, P‐value = .045), and the 2 variants are in complete linkage disequilibrium. The mutation of ABCB1 rs1128503 may decrease the recurrence of clinical events (OR = 0.211, 95% CI = 0.046‐0.957, P‐value = .044). Genetic testing (ABCB1 and P2Y12) may provide useful information to prevent ischaemic events prior to the initiation of antiplatelet therapy.     

Identification of factors affecting tacrolimus level and 5-year clinical outcome in kidney transplant patients

The purpose of this study was to identify and characterize the association of various clinical variables and CYP3A5 genotypes with the pharmacokinetics of tacrolimus and outcome over 1–5 years in kidney transplantation patients in Korea. A total of 129 recipients (aged 18–65 years) administered tacrolimus were genotyped for CYP3A5 (6986A>G in intron 3; rs776746). Clinical covariates and trough levels, doses and dose‐adjusted trough levels of tacrolimus, as well as complications during the 1–5 years after transplantation, were analysed. A linear mixed model was used to investigate potential factors affecting the trough levels, doses and dose‐adjusted levels of tacrolimus. We identified factors affecting chronic allograft nephropathy (CAN) and tacrolimus‐related complications. After adjusting for sex, body‐weight and doses of corticosteroids and mycophenolate mofetil, we noted that CYP3A5 genotypes had the most profound effect on the dose and dose‐adjusted trough levels of tacrolimus 1–5 years after transplantation (p < 0.001). Trough levels of tacrolimus were associated with post‐transplantation hyperlipidaemia (p < 0.05), and estimated glomerular filtration rate was associated with CAN (p < 0.05). Therefore, the CYP3A5 genotype is a variable marker for tacrolimus dose requirement, and the trough level of tacrolimus should be controlled to minimize post‐transplant hyperlipidaemia to achieve optimum outcome.     

ABCC3 Polymorphisms and mRNA Expression Influence the Concentration of a Carboxylic Acid Metabolite in Patients on Clopidogrel and Aspirin Therapy

Acetylsalicylic acid (ASA) and clopidogrel combined therapy has been reported to be beneficial in patients with acute coronary syndrome (ACS). Antiplatelet drug resistance, especially to clopidogrel, is a multifactorial phenomenon that affects a large number of ACS patients. The genetic contribution to this drug response is not fully elucidated. We investigated the relationship of ABC‐type efflux subfamily C member 3 (ABCC3) polymorphisms and mRNA expression with plasma concentrations of clopidogrel, salicylic acid (SA) and a carboxylic acid metabolite (CAM). Clopidogrel, CAM and SA plasma concentrations were measured simultaneously by liquid chromatography–tandem mass spectrometry (LCMS/MS) from 83 ACS patients undergoing percutaneous coronary intervention. ABCC3 (rs757421, rs733392 and rs739923) and CYP2C19*2 (rs4244285) polymorphisms as well as mRNA expression were evaluated. A positive correlation was found between CAM concentrations and ABCC3 mRNA expression (r = 0.494, p < 0.0001). Patients carrying genotype AA (rs757421 variant) had higher CAM concentrations and ABCC3 mRNA expression as compared to those of GG + GA carriers (p = 0.017). A multiple linear regression analysis revealed that ABCC3 mRNA expression (p = 0.017), rs757421 AA genotype (p = 0.001), blood collection time (p = 0.018) and clopidogrel dose (p = 0.001) contributed to the concentration of CAM. No associations were observed for the CYP2C19*2 polymorphism. These results suggest that up‐regulation of ABCC3 mRNA expression leads to increased plasma CAM levels through MRP3‐mediated cell efflux. The ABCC3 rs757421 polymorphism may contribute to gene expression. Therefore, ABCC3 may be a potential biomarker for the response to clopidogrel.     

Association of OPRD1 Gene Variants with Opioid Dependence in Addicted Male Individuals Undergoing Methadone Treatment in the North of Iran

Genetic association of rs678849 along with neuroimaging and biomarker phenotypes, parallel with the known involvements of the OPRD1 in drug abuse, provided additional support for targeting these receptors as potential therapeutic targets in both neurodegenerative diseases and neuropsychiactric disorders such as Alzheimer’s disease. Samples were selected among 202 opium-addicted participants undergoing methadone treatment and 202 healthy controls. Genomic DNA of all subjects was extracted from whole blood samples through a Salting Out procedure. Four variants (rs678849, 2236857, 2236855, and 760589) were genotyped in the studied subjects using ARMS-PCR. The analysis was performed using SNPalyze and SPSS ver.20 software. According to single locus analysis, rs678849 under dominant model (p < 0.001), rs2236857 under recessive model (p = 0.006), and the two variants, rs2236855 and rs760589 under co-dominant model, showed significant contributions between groups (p = 0.001 and p = 0.009, respectively). rs2236855 was associated with the development of libido dysfunction in opium-addicted patients undergoing methadone treatment (p = 0.011). Through haplotype analyses, five haplotypes with frequency of more than 5% displayed significant association with opioid dependence in study participants. In conclusion, the four studied OPRD1 gene variants and their haplotypes can play important roles in susceptibility to opioid dependence.     

The CYP2C19*2 and CYP2C19*17 Polymorphisms play a Vital Role in Clopidogrel Responsiveness after Percutaneous Coronary Intervention: A Pharmacogenomics Study

Clopidogrel inhibits platelet activation and aggregation by blocking the P2Y₁₂ receptor. Dual antiplatelet therapy with clopidogrel and aspirin is recommended treatment by current guidelines for patients undergoing percutaneous interventions. Recurrent ischaemic cardiac events after this treatment showed lack of clopidogrel responsiveness. We aimed to investigate the most noticeable variants in the genes involved in clopidogrel pharmacokinetics and pharmacodynamics. A total of 347 Turkish patients who underwent percutaneous coronary interventions with stent implantation were included in our study. Platelet reactivity (PRU) and % inhibition were measured with VerifyNow P2Y₁₂ assay in blood samples collected from patients who took a standard dose of clopidogrel (75 mg/day) for at least 7 days. The variants in the CYP2C19, CYP3A4, CYP2B6, ABCB1, ITGB3 and PON1 genes were genotyped using the Sequenom MassARRAY system. When grouped, the patients with PRU values >208 as non‐responsiveness to clopidogrel therapy; 104 (30%) patients were non‐responders and 243 (70%) patients were responders. A significant association was found between the CYP2C19*2 (G636A) polymorphism and non‐responsiveness to clopidogrel therapy (p < 0.001). An allele frequency of this single nucleotide polymorphism was high in non‐responders; its odds ratio was 2.92 compared with G allele (p < 0.001). PRU values of CT genotypes were lower (p = 0.029) and % inhibition values of CT genotypes were higher (p = 0.008) compared with CC genotypes for the CYP2C19*17 (C806T) polymorphism. None of the other genetic variants were found to be statistically associated with non‐responsiveness to clopidogrel and antiplatelet activity. Our findings suggest that the CYP2C19*2 polymorphism is associated with non‐responsiveness to clopidogrel therapy and the CYP2C19*17 polymorphism enhances antiplatelet activity of clopidogrel. Depending on haplotypes of these two polymorphisms, clopidogrel‐treated patients can be protected or not from stent thrombosis and ischaemic events.     

Influence of carboxylesterase 2 genetic polymorphisms on mycophenolic acid pharmacokinetics in Japanese renal transplant recipients

1. Mycophenolic acid (MPA), converted from the prodrug mycophenolate mofetil (MMF), is generated by intestinal and hepatic esterases. The role of carboxylesterase (CES) in MMF hydrolysis was examined in vitro using human liver microsomes. V_max and K_m values of MMF hydrolysis in pooled human liver microsomes were 1368?±?44 nmol min^?1 mg^?1 protein and 1030?±?65?μM, respectively.

2. Hydrolytic activity was inhibited by the CES inhibitors phenylmethylsulfonylfluoride, bis-p-nitorophenylphosphate and diisopropylfluorophosphate, with IC₅₀ values of 77.1, 3.59 and 0.0312?μM, respectively.

3. Eighty Japanese renal transplant recipients that received repeated-doses of MMF, tacrolimus and prednisolone, were evaluated for MPA pharmacokinetics 28 days after transplantation to investigate the relationship between MPA pharmacokinetics and CES2 genetic polymorphisms.

4. No significant differences in MPA pharmacokinetics were observed between CES2 A4595G, C8721T or A-1548G genotype groups. CES2 allelic variants also did not appear to affect plasma MPA concentrations between individuals.

5. In conclusion, the study demonstrated that while CES1 and/or CES2 are involved in the hydrolysis of MMF to MPA, CES2 allelic variants appeared to make only a minor contribution to inter-personal differences in MPA pharmacokinetics.

     

Effects of 1,8-cineole on electrophysiological parameters of neurons of the rat superior cervical ganglion

• 1 1,8‐Cineole is a non‐toxic small terpenoid oxide believed to have medicinal properties in folk medicine. It has been shown to have various pharmacological effects, including blockade of the compound action potential (AP). In the present study, using intracellular recording techniques, we investigated the effects of 1,8‐cineole on the electrophysiological parameters of neurons of the superior cervical ganglion (SCG) in rats.
• 2 1,8‐Cineole (0.1–6 mmol/L) showed reversible and concentration‐dependent effects on various electrophysiological parameters. At 3 and 6 mmol/L, but not at 0.1 and 1 mmol/L, 1,8‐cineole significantly diminished the input resistance (R_i) and altered the resting potential (E_m) to more positive values. At 6 mmol/L, 1,8‐cineole completely blocked all APs within 2.7 ± 0.6 min (n = 12). In neurons exposed to 3 and 1 mmol/L 1,8‐cineole, the effects regarding excitability varied from complete AP blockade to minor inhibition of AP parameters. The depolarization of E_m and the decrease in R_i induced by 6 mmol/L 1,8‐cineole were unaltered by 200 µmol/L niflumic acid, a well known blocker of Ca²⁺‐activated Cl^? currents.
• 3 Significant correlations (Pearson correlation test) were found between changes in E_m and decreases in AP amplitude (r = –0.893; P < 0.00282) and maximum ascendant inclination (r = –0.799; P < 0.0173), but not for maximum descendant inclination (r = 0.598; P < 0.117). Application of current to restore the transmembrane potential equal to control E_m values in the presence of 6 mmol/L 1,8‐cineole resulted in the partial recovery of AP.
• 4 The present study shows that 1,8‐cineole effectively blocks the excitability of SCG neurons, probably through various mechanisms, one of which acts indirectly via depolarization of the neuronal cytoplasmatic membrane.

     

Effect of the CYP2C19*2 and *3 genotypes, ABCB1 C3435T and PON1 Q192R alleles on the pharmacodynamics and adverse clinical events of clopidogrel in Chinese people after percutaneous coronary intervention

Purpose

Chinese people are more frequent carriers of cytochrome P450 2C19 (CYP2C19) loss-of-function alleles than Caucasians. The effect of the ATP-binding cassette, sub-family B, member 1 (ABCB1), and paraoxonase 1 (PON1) variants on platelet reactivity and clinical outcomes of clopidogrel treatment has not yet been reported in Chinese patients after percutaneous coronary intervention. The aim of this study was to investigate the effect of the CYP2C19, ABCB1, and PON1 variants on clopidogrel pharmacodynamics and clinical outcomes in these patients.

Methods

Six hundred and seventy patients after percutaneous coronary intervention were enrolled in a single-center registry. The antiplatelet effect of clopidogrel was assessed by thromboelastography, and the CYP2C19, ABCB1, and PON1 genotypes were detected by the ligase detection reaction. Primary clinical endpoints included cardiovascular death, nonfatal myocardial infarction, target vessel revascularization, and stent thrombosis. The secondary clinical endpoints were thrombolysis in myocardial infarction bleeding. The follow-up period was 12 months.

Results

The frequency of the CYP2C19 loss-of-function alleles was relatively high (57.3 %). The risk of a low response to clopidogrel and composite ischemic events increased with the number of CYP2C19 loss-of-function alleles. However, there were not significant differences in clopidogrel pharmacodynamics and clinical outcomes across the ABCB1 and PON1 genotype groups; bleeding was not significantly different across the CYP2C19, ABCB1, and PON1 genotype groups.

Conclusions

The CYP2C19 loss-of-function alleles had a gene dose effect on the pharmacodynamics and composite ischemic events of clopidogrel in our study population. Neither the ABCB1 nor the PON1 genotype significantly influenced the antiplatelet effect and clinical outcomes of clopidogrel in these patients.     

Physiologically-Based Pharmacokinetic Modeling to Predict Methylphenidate Exposure Affected by Interplay Among Carboxylesterase 1 Pharmacogenetics,Drug-Drug Interactions,and Sex

Background and objectiveThe pharmacokinetics (PK) of methylphenidate (MPH) differ significantly among individuals. Carboxylesterase 1 (CES1) is the primary enzyme metabolizing MPH, and its function is affected by genetic variants, drug-drug interaction (DDI), and sex. The object of this study is to evaluate CES1 pharmacogenetics as related to MPH metabolism using human liver samples and develop a physiologically-based pharmacokinetic (PBPK) modeling approach to investigate the influence of CES1 genotypes and other factors on MPH PK.MethodsThe effect of the CES1 variant G143E (rs71647871) on MPH metabolism was studied utilizing 102 individual human liver S9 (HLS9) fraction samples. PBPK models were developed using the population-based PBPK software PK-Sim® by incorporating the HLS9 incubation data. The established models were applied to simulate MPH PK profiles under various clinical scenarios, including different genotypes, drug-alcohol interactions, and the difference between males and females.ResultsThe HLS9 incubation study showed that subjects heterozygous for the CES1 variant G143E metabolized MPH at a rate of approximately 50% of that in non-carriers. The developed PBPK models successfully predicted the exposure alteration of MPH from the G143E genetic variant, ethanol-MPH DDI, and sex. Importantly, the study suggests that male G143E carriers who are alcohol consumers are at a higher risk of MPH overexposure.ConclusionPBPK modeling provides a means for better understanding the mechanisms underlying interindividual variability in MPH PK and PD and could be utilized to develop a safer and more effective MPH pharmacotherapy regimen.     

ABCB1 Variation Affects Myelosuppression,Progression‐free Survival and Overall Survival in Paclitaxel/Carboplatin‐treated Ovarian Cancer Patients

The standard chemotherapy for ovarian cancer is paclitaxel/carboplatin. Patients often exhibit myelosuppressive toxicity, and the treatment response varies considerably. In this study, we investigated the previously reported SNPs 1199G>A (rs2229109), 1236C>T (rs1128503), 2677G>T/A (rs2032582), 3435C>T (rs1045642) in ABCB1, and 1196A>G (rs10509681) in CYP2C8 and their association with treatment‐induced myelosuppression, progression‐free survival (PFS) and overall survival (OS). From the phase III study, OAS‐07OVA, 525 patients (All) treated with carboplatin and paclitaxel administered as Paclical (Arm A, n = 260) or Taxol^® (Arm B, n = 265) were included and genotyped using pyrosequencing. Genotype associations with myelosuppression, PFS and OS were investigated using anova , Kaplan–Meier analysis and Cox proportional hazard models. The most prominent finding was for the ABCB1 variant 3435TT, which was significantly associated with increased PFS in All (hazard ratio (HR) = 0.623), in Arm A (HR = 0.590) and in Arm B (HR = 0.627), as well as increased OS in All (HR = 0.443) and in Arm A (HR = 0.372) compared to the wild‐type, 3435CC. For toxicity, the most interesting finding concerned the haplotype, including 1236TT, 2677TT and 3435TT, which was associated with higher neutrophil values in Arm B (p = 0.039) and less neutrophil decrease in All (p = 0.048) and in Arm B (p = 0.021). It is noteworthy that the results varied depending on the treatment arm which indicates that the effects of ABCB1 variants vary with the treatment regimen. Our results reflect the contradictory results of previous studies, confirming that small variations in the composition of treatment regimens and patient populations may influence the interpretation of SNPs effects on treatment outcome.     

Systemic administration of 2‐hydroxypropyl‐β‐cyclodextrin to symptomatic Npc1‐deficient mice slows cholesterol sequestration in the major organs and improves liver function

In Niemann–Pick type C (NPC) disease, loss‐of‐function mutations in either NPC1 or NPC2 result in progressive accumulation of unesterified cholesterol (UC) and glycosphingolipids in all organs, leading to neurodegeneration, pulmonary dysfunction and sometimes liver failure. There is no cure for this disorder. Studies using primarily NPC mouse models have shown that systemic administration of 2‐hydroxypropyl‐β‐cyclodextrin (2HPβCD), starting in early neonatal life, diminishes UC accumulation in most organs, slows disease progression and extends lifespan. The key question now is whether delaying the start of 2HPβCD treatment until early adulthood, when the amount of entrapped UC throughout the body is markedly elevated, has any of the benefits found when treatment begins at 7 days of age. In the present study, Npc1^?/? and Npc1^+/+ mice were given saline or 2HPβCD subcutaneously at 49, 56, 63 and 70 days of age, with measurements of organ weights, liver function tests and tissue cholesterol levels performed at 77 days. In Npc1^?/? mice, treatment with 2HPβCD from 49 days reduced whole‐liver cholesterol content at 77 days from 33.0 ± 1.0 to 9.1 ± 0.5 mg/organ. Comparable improvements were seen in other organs, such as the spleen, and in the animal as a whole. There was a transient increase in biliary cholesterol concentration in Npc1^?/? mice after 2HPβCD. Plasma alanine aminotransferase and aspartate aminotransferase activities in 77‐day‐old 2HPβCD‐treated Npc1^?/? mice were reduced compared with saline‐treated controls. The lifespan of Npc1^?/? mice given 2HPβCD marginally exceeded that of the saline‐treated controls (99 ± 1.1 vs 94 ± 1.4 days, respectively; P < 0.05). Thus, 2HPβCD is effective in mobilizing entrapped cholesterol in late‐stage NPC disease leading to improved liver function.     

Resequencing of Nicotinic Acetylcholine Receptor Genes and Association of Common and Rare Variants with the Fagerstr?m Test for Nicotine Dependence

Common single-nucleotide polymorphisms (SNPs) at nicotinic acetylcholine receptor (nAChR) subunit genes have previously been associated with measures of nicotine dependence. We investigated the contribution of common SNPs and rare single-nucleotide variants (SNVs) in nAChR genes to Fagerström test for nicotine dependence (FTND) scores in treatment-seeking smokers. Exons of 10 genes were resequenced with next-generation sequencing technology in 448 European-American participants of a smoking cessation trial, and CHRNB2 and CHRNA4 were resequenced by Sanger technology to improve sequence coverage. A total of 214 SNP/SNVs were identified, of which 19.2% were excluded from analyses because of reduced completion rate, 73.9% had minor allele frequencies <5%, and 48.1% were novel relative to dbSNP build 129. We tested associations of 173 SNP/SNVs with the FTND score using data obtained from 430 individuals (18 were excluded because of reduced completion rate) using linear regression for common, the cohort allelic sum test and the weighted sum statistic for rare, and the multivariate distance matrix regression method for both common and rare SNP/SNVs. Association testing with common SNPs with adjustment for correlated tests within each gene identified a significant association with two CHRNB2 SNPs, eg, the minor allele of rs2072660 increased the mean FTND score by 0.6 Units (P=0.01). We observed a significant evidence for association with the FTND score of common and rare SNP/SNVs at CHRNA5 and CHRNB2, and of rare SNVs at CHRNA4. Both common and/or rare SNP/SNVs from multiple nAChR subunit genes are associated with the FTND score in this sample of treatment-seeking smokers.     

Pharmacogenetics of Risperidone‐Induced Insulin Resistance in Children and Adolescents with Autism Spectrum Disorder

The purpose of this study was to explore the association of genetic polymorphism of genes related to pharmacokinetics or pharmacodynamics with insulin resistance in children and adolescents with autism spectrum disorder (ASD) and treated with risperidone. All 89 subjects underwent measurement of fasting blood glucose and insulin levels, body‐weight and height. Genotyping was performed by TaqMan real‐time polymerase chain reaction (PCR) (pharmacokinetics genes: cytochrome P450 2D6 (CYP2D6) *4 (rs3892097), *5 (gene deletion), *10 (rs1065852) and *41 (rs28371725), ATP‐binding cassette transporter B1 (ABCB1) 2677 G>T/A (rs2032582) and 3435C>T (rs1045642) and pharmacodynamics genes: dopamine receptor D2 (DRD2) Tag‐SNP (C>T) (rs4436578), DRD2 Tag1A (C>T) (rs1800497), leptin gene (LEP) ‐2548G>A (rs7799039), ghrelin gene (GHRL) ‐604G>A (rs27647) and brain‐derived neurotrophic factor (BDNF) 196G>A (rs6265)). Drug levels were analysed by liquid chromatography–tandem mass spectrometry (LC‐MS/MS). The results revealed that 5 (5.62%) patients presented with hyperglycaemia. Insulin resistance was detected in 15 (16.85%) patients. Insulin resistance was associated with LEP 2548 G>A and BDNF 196 G>A polymorphism (p = 0.051 and p = 0.03). There was no association of pharmacokinetic gene polymorphisms (CYP2D6 and ABCB1) and risperidone levels with insulin resistance. Multiple regression analysis indicated that BDNF 196 G>A polymorphism was significantly associated with insulin resistance (p = 0.025). This finding suggested that BDNF 196 G>A polymorphism may be a genetic marker for predicting insulin resistance before initiating treatment in patients treated with risperidone. Because of the small sample size, further studies are needed to confirm these results.