Cytochrome P450 2D6 (CYP2D6) gene duplication and multiplication can result in ultrarapid drug metabolism and therapeutic failure or excessive response in patients. Long range polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP) and sequencing are usually used for genotyping CYP2D6 duplication/multiplications and identification, but are labor intensive, time consuming, and costly.
We developed a simple allele quantification-based Pyrosequencing genotyping method that facilitates CYP2D6 copy number variation (CNV) genotyping while also identifying allele-specific CYP2D6 CNV in heterozygous samples. Most routine assays do not identify the allele containing a CNV. A total of 237 clinical and Coriell DNA samples with different known CYP2D6 gene copy numbers were genotyped for CYP2D6 *2, *3, *4, *6, *10, *17, *41 polymorphisms and CNV determination.
The CYP2D6 gene allele quantification/identification were determined simultaneously with CYP2D6*2, *3, *4, *6, *10, *17, *41 genotyping. We determined the exact CYP2D6 gene copy number, identified which allele had the duplication or multiplication, and assigned the correct phenotype and activity score for all samples.
Our method can efficiently identify the duplicated CYP2D6 allele in heterozygous samples, determine its copy number in a fraction of time compared to conventional methods and prevent incorrect ultrarapid phenotype calls. It also greatly reduces the cost, effort and time associated with CYP2D6 CNV genotyping.
Thiazide diuretics have been associated with increased risk for new onset diabetes (NOD), but pharmacogenetic markers of thiazide-induced NOD are not well studied. Single nucleotide polymorphisms (SNPs) in the Transcription Factor 7-Like 2 gene (TCF7L2) represent the strongest and most reproducible genetic associations with diabetes. We investigated the association of tag SNPs in TCF7L2 with thiazide-induced NOD.
We identified cases that developed NOD and age, gender, and race/ethnicity-matched controls from the INternational VErapamil SR Trandolapril STudy (INVEST). INVEST compared cardiovascular outcomes between two antihypertensive treatment strategies in ethnically diverse patients with hypertension and coronary artery disease. We genotyped 101 TCF7L2 tag SNPs and used logistic regression to test for pharmacogenetic (SNP*hydrochlorothiazide treatment) interactions. Permuted interaction p values were corrected with the PACT test and adjusted for diabetes-related variables.
In INVEST whites, we observed three TCF7L2 SNPs with significant SNP*treatment interactions for NOD. The strongest pharmacogenetic interaction was observed for rs7917983 (synergy index 3.37 [95%CI 1.72–6.59], p=5.0×10−4, PACT =0.03), which was associated with increased NOD risk in hydrochlorothiazide-treated patients (OR 1.53 [1.04–2.25], p=0.03) and decreased NOD risk in non hydrochlorothiazide-treated patients (OR 0.48 [0.27–0.86], p=0.02). The TCF7L2 SNP rs4506565, previously associated with diabetes, showed a similar, significant pharmacogenetic association.
Our results suggest that hydrochlorothiazide treatment is an environmental risk factor that increases diabetes risk beyond that attributed to TCF7L2 variation in white, hypertensive patients. Further study and replication of our results is needed to confirm pharmacogenetic influences of TCF7L2 SNPs on thiazide-induced NOD.
pharmacogenetics; TCF7L2; diabetes mellitus; hydrochlorothiazide
Chronic obstructive pulmonary disease (COPD) is associated with increased morbidity and mortality and reduced quality of life. Novel interventions are needed to improve outcomes in COPD patients. The present study assessed the effects of a telephone-based coping skills intervention on psychological and somatic quality of life and on the combined medical endpoint of COPD-related hospitalizations and all-cause mortality.
We conducted a dual-site, randomized clinical trial with assessments at baseline and after 16 weeks of treatment. The study population comprised 326 outpatients with COPD aged 38 to 81 years, randomized to Coping Skills training (CST) or to COPD Education (COPD-ED). Patients completed a battery of quality of life (QoL) instruments, pulmonary function tests, and functional measures and were followed for up to 4.4 years to assess medical outcomes.
The CST group exhibited greater improvements in psychological QoL compared to controls (P = .001), including less depression (Cohen’s d=0.22 [95%CI 0.08, 0.36]) and anxiety (d=0.17 [95%CI 0.02, 0.33]), and better overall mental health (d=0.17 [95%CI 0.03, 0.32]), emotional role functioning (d= 0.29 [95%CI 0.10, 0.48]), vitality (d= 0.27 [95%CI 0.11, 0.42]), and social functioning (d= 0.21 [95%CI 0.03, 0.38]). A significant baseline psychological QoL by Treatment group interaction revealed that CST with lower QoL at baseline achieved even greater improvements in psychological QoL compared to COPE-ED. CST participants also exhibited greater improvements in Somatic QoL (P = .042), including greater improvements in pulmonary QoL (d= 0.13 [95%CI 0.01, 0.24]), less fatigue (d= 0.34 [95%CI 0.18, 0.50]), and less shortness of breath (d= 0.11 [95%CI −0.01, 0.23]) and greater improvement in distance walked on the 6 Minute Walk Test (d= 0.09 [95%CI 0.01, 0.16]). However, there was no significant difference in risk of time to COPD-related hospitalization or all-cause mortality between CST (34 events) and COPD-ED (32 events) (P= 0.430).
A telehealth coping skills training intervention produced clinically meaningful improvements in quality of life and functional capacity, but no overall improvement in risk of COPD-related hospitalization and all-cause mortality.
clinicaltrials.gov Identifier NCT00736268
COPD; stress; depression; coping skills; disease-management
Background and Purpose
Meta-analyses of extant genome-wide data illustrate the need to focus on subtypes of ischemic stroke for gene discovery. The NINDS Stroke Genetics Network (SiGN) contributes substantially to meta-analyses that focus on specific subtypes of stroke.
The NINDS Stroke Genetics Network (SiGN) includes ischemic stroke cases from 24 Genetic Research Centers (GRCs), 13 from the US and 11 from Europe. Investigators harmonize ischemic stroke phenotyping using the web-based Causative Classification of Stroke (CCS) system, with data entered by trained and certified adjudicators at participating GRCs. Through the Center for Inherited Diseases Research (CIDR), SiGN plans to genotype 10,296 carefully phenotyped stroke cases using genome-wide SNP arrays, and add to these another 4,253 previously genotyped cases for a total of 14,549 cases. To maximize power for subtype analyses, the study allocates genotyping resources almost exclusively to cases. Publicly available studies provide most of the control genotypes. CIDR-generated genotypes and corresponding phenotypic data will be shared with the scientific community through dbGaP, and brain MRI studies will be centrally archived.
The SiGN consortium, with its emphasis on careful and standardized phenotyping of ischemic stroke and stroke subtypes, provides an unprecedented opportunity to uncover genetic determinants of ischemic stroke.
ischemic stroke; genetics; genomics
VKORC1 and CYP2C9 are important contributors to warfarin dose variability, but explain less variability for individuals of African descent than for those of European or Asian descent. We aimed to identify additional variants contributing to warfarin dose requirements in African Americans.
We did a genome-wide association study of discovery and replication cohorts. Samples from African-American adults (aged ≥18 years) who were taking a stable maintenance dose of warfarin were obtained at International Warfarin Pharmacogenetics Consortium (IWPC) sites and the University of Alabama at Birmingham (Birmingham, AL, USA). Patients enrolled at IWPC sites but who were not used for discovery made up the independent replication cohort. All participants were genotyped. We did a stepwise conditional analysis, conditioning first for VKORC1 −1639G→A, followed by the composite genotype of CYP2C9*2 and CYP2C9*3. We prespecified a genome-wide significance threshold of p<5×10−8 in the discovery cohort and p<0·0038 in the replication cohort.
The discovery cohort contained 533 participants and the replication cohort 432 participants. After the prespecified conditioning in the discovery cohort, we identified an association between a novel single nucleotide polymorphism in the CYP2C cluster on chromosome 10 (rs12777823) and warfarin dose requirement that reached genome-wide significance (p=1·51×10−8). This association was confirmed in the replication cohort (p=5·04×10−5); analysis of the two cohorts together produced a p value of 4·5×10−12. Individuals heterozygous for the rs12777823 A allele need a dose reduction of 6·92 mg/week and those homozygous 9·34 mg/week. Regression analysis showed that the inclusion of rs12777823 significantly improves warfarin dose variability explained by the IWPC dosing algorithm (21% relative improvement).
A novel CYP2C single nucleotide polymorphism exerts a clinically relevant effect on warfarin dose in African Americans, independent of CYP2C9*2 and CYP2C9*3. Incorporation of this variant into pharmacogenetic dosing algorithms could improve warfarin dose prediction in this population.
National Institutes of Health, American Heart Association, Howard Hughes Medical Institute, Wisconsin Network for Health Research, and the Wellcome Trust.
To identify novel genes influencing blood pressure response to thiazide diuretic therapy for hypertension, we conducted genome-wide association meta-analyses of ≈1.1 million single nucleotide polymorphisms in a combined sample of 424 European Americans with primary hypertension treated with hydrochlorothiazide from the Pharmacogenomic Evaluation of Antihypertensive Responses Study (N=228) and the Genetic Epidemiology of Responses to Antihypertensive Study (N=196). Polymorphisms associated with blood pressure response at p<10-5 were tested for replication of the associations in independent samples of hydrochlorothiazide-treated European hypertensives. The rs16960228 polymorphism in protein kinase C, alpha replicated for same-direction association with diastolic blood pressure response in the Nordic Diltiazem Study (N=420) and the Genetics of Drug Responsiveness in Essential Hypertension Study (N=206), and the combined four-study meta-analysis p-value achieved genome-wide significance (p=3.3 × 10-8). Systolic/diastolic blood pressure responses were consistently greater in carriers of the rs16960228 A allele than in GG homozygotes (4/4 mmHg greater) across study samples. The rs2273359 polymorphism in the GNAS-EDN3 region also replicated for same-direction association with systolic blood pressure response in the Nordic Diltiazem Study, and the combined three-study meta-analysis p-value approached genome-wide significance (p=5.5 × 10-8). The findings document clinically-important effects of genetic variation at novel loci on blood pressure response to a thiazide diuretic, which may be a basis for individualization of antihypertensive drug therapy and identification of new drug targets.
Hypertension; high blood pressure; antihypertensive therapy/diuretics; hydrochlorothiazide; genomics; pharmacogenomics; protein kinase C
We sought to identify novel pharmacogenetic markers associated with cardiovascular outcomes in patients with hypertension on antihypertensive therapy. We genotyped a 1:4 case:control cohort (n=1345) on the Illumina HumanCVD Beadchip from the International Verapamil SR-Trandolapril Study, where participants were randomized to a β blocker strategy or a calcium channel blocker strategy. Genome-spanning SNP × treatment interaction analyses of non-synonymous SNPs were conducted in white and Hispanic race/ethnic groups. Top hits from whites were tested in Hispanics for consistency. A genetic risk score was constructed from the top three signals and tested in the Nordic Diltiazem study. SIGLEC12 rs16982743 and A1BG rs893184 had a significant interaction with treatment strategy for adverse cardiovascular outcomes (International Verapamil SR-Trandolapril Study whites and Hispanics combined interaction P=0.0038, and 0.0036, respectively). A genetic risk score including rs16982743, rs893184 and rs4525 in F5, was significantly associated with treatment-related adverse cardiovascular outcomes in whites and Hispanics from the International Verapamil SR-Trandolapril Study and in the Nordic Diltiazem study (meta-analysis interaction P=2.39×10−5). In patients with a genetic risk score of zero or 1, calcium channel blocker treatment was associated with lower risk (OR (95% CI) = 0.60 (0.42-0.86)), and in those with a genetic risk score of 2-3, calcium channel blocker treatment was associated with higher risk, OR (95% CI) = 1.31 (1.08-1.59)). These results suggest cardiovascular outcomes may differ based on SIGLEC12, A1BG, F5 genotypes and antihypertensive treatment strategy. These specific genetic associations and our risk score provide insight into a potential approach to personalized antihypertensive treatment selection.
Pharmacogenomics; Hypertension; antihypertensive agents; cardiovascular outcomes; genetic variation; beta-blockers, calcium channel blockers
The clinical utility of genotype-guided (pharmacogenetically based) dosing of warfarin has been tested only in small clinical trials or observational studies, with equivocal results.
We randomly assigned 1015 patients to receive doses of warfarin during the first 5 days of therapy that were determined according to a dosing algorithm that included both clinical variables and genotype data or to one that included clinical variables only. All patients and clinicians were unaware of the dose of warfarin during the first 4 weeks of therapy. The primary outcome was the percentage of time that the international normalized ratio (INR) was in the therapeutic range from day 4 or 5 through day 28 of therapy.
At 4 weeks, the mean percentage of time in the therapeutic range was 45.2% in the genotype-guided group and 45.4% in the clinically guided group (adjusted mean difference, [genotype-guided group minus clinically guided group], −0.2; 95% confidence interval, −3.4 to 3.1; P=0.91). There also was no significant between-group difference among patients with a predicted dose difference between the two algorithms of 1 mg per day or more. There was, however, a significant interaction between dosing strategy and race (P=0.003). Among black patients, the mean percentage of time in the therapeutic range was less in the genotype-guided group than in the clinically guided group. The rates of the combined outcome of any INR of 4 or more, major bleeding, or thromboembolism did not differ significantly according to dosing strategy.
Genotype-guided dosing of warfarin did not improve anticoagulation control during the first 4 weeks of therapy. (Funded by the National Heart, Lung, and Blood Institute and others; COAG ClinicalTrials.gov number, NCT00839657.)
The VKORC1 Asp36Tyr single nucleotide polymorphism (SNP) is one of the most promising predictors of high warfarin dose, but data on its population prevalence is incomplete. We determined the frequency of this SNP in participants from seven countries on four continents and investigated its effect on warfarin dose requirement. 1000 samples were analyzed to define the population prevalence of this SNP. Those samples included individuals from Egypt, Ghana, Sudan, Kenya, Saudi Arabia, Peru and African Americans from the United States. 206 Egyptian samples were then used to investigate the effect of this SNP on warfarin dose requirements. This SNP was most frequent among Kenyans and Sudanese, with a minor allele frequency (MAF) of 6% followed by Saudi Arabians and Egyptians with a MAF of 3% and 2.5%, respectively. It was not detected in West Africans, based on our data from Ghana, and a large cohort of African Americans. Egyptian carriers of the VKORC1 Tyr36 showed higher warfarin dose requirement (57.1±29.4 mg/week) than those with the Asp36Asp genotype (35.8±16.6 mg/week; P<0.03). In linear regression analysis, this SNP had the greatest effect size among the genetic factors (16.6 mg/week increase in dose per allele), and improved the warfarin dose variability explained in Egyptians (model R2 from 31% to 36.5%). The warfarin resistant VKORC1 Asp36Tyr appears to be confined to north-eastern Africa and nearby Middle-Eastern populations, but in those populations where it is present, it has a significant influence on warfarin dose requirement and the percent of warfarin dose variability that can be explained.
Warfarin; Pharmacogenetics; VKORC1 Asp36Tyr; polymorphism; Egyptians
Recent years have seen great advances in our understanding of genetic contributors to drug response. Drug discovery and development around targeted genetic (somatic) mutations has led to a number of new drugs with genetic indications, particularly for the treatment of cancers. Our knowledge of genetic contributors to variable drug response for existing drugs has also expanded dramatically, such that the evidence now supports clinical use of genetic data to guide treatment in some situations, and across a variety of therapeutic areas. Clinical implementation of pharmacogenetics has seen substantial growth in recent years and groups are working to identify the barriers and best practices for pharmacogenetic-guided treatment. The advances and challenges in these areas are described and predictions about future use of genetics in drug therapy are discussed.
clinical implementation; pharmacogenetics; pharmacogenomics
To evaluate pregnancy outcomes according to 2009 Institute of Medicine (IOM) gestational weight gain guidelines.
This study is a secondary analysis of a preeclampsia prevention trial among nulliparas carrying singletons. Odds ratios and 95% confidence intervals (adjusted for maternal age, race, smoking, and treatment group) were calculated based on total weight gain below or above the IOM guidelines, stratified by prepregnancy body mass index (BMI). The referent group was weight gain within the guidelines.
Of 8,293 pregnancies, 9.5% had weight gain below, 17.5% within, and 73% above IOM guidelines. With excess weight gain, all BMI categories had an increased risk of hypertensive disorders; normal weight and overweight women also had increased risk of cesarean delivery and infant birth weight at or above the 90th centile but a decreased risk of weight below the10th centile. There were no consistent associations with insufficient weight gain and adverse outcomes.
Excess weight gain was prevalent and associated with an increased risk of hypertensive disorders, cesarean delivery and large for gestational age infants..
The University of Florida and Shands Hospital recently launched a genomic medicine program focused on the clinical implementation of pharmacogenetics called the Personalized Medicine Program. We focus on a preemptive, chip-based genotyping approach that is cost effective, while providing experience that will be useful as genomic medicine moves towards genome sequence data for patients becoming available. The Personalized Medicine Program includes a regulatory body that is responsible for ensuring that evidence-based examples are moved to clinical implementation, and relies on clinical decision support tools to provide healthcare providers with guidance on use of the genetic information. The pilot implementation was with CYP2C19-clopidogrel and future plans include expansion to additional pharmacogenetic examples, along with aiding in implementation in other health systems across Florida.
Purpose of review
To review the most promising genetic markers associated with the variability in the safety or efficacy of warfarin and clopidogrel and highlight the verification and validation initiatives for translating clopidogrel and warfarin pharmacogenetic tests to clinical practice.
Rapid advances in pharmacogenetics, continuous decrease in genotyping cost, development of point-of-care devices and the newly established clinical genotyping programs at several institutions hold the promise of individualizing clopidogrel and warfarin based on genotype. Guidelines have been established to assist clinicians in prescribing clopidogrel or warfarin dose based on genotype. However, the clinical utility of clopidogrel and warfarin is still limited. Accordingly, large randomized clinical trials are underway to define the role of clopidogrel and warfarin pharmacogenetics in clinical practice.
Pharmacogenetics has offered compelling evidence toward the individualization of clopidogrel and warfarin therapies. The rapid advances in technology make the clinical implementation of clopidogrel and warfarin pharmacogenetics possible. The clinical genotyping programs and the ongoing clinical trials will help in overcoming some of the barriers facing the clinical implementation of clopidogrel and warfarin pharmacogenetics.
clinical implementation; clopidogrel; personalized medicine; pharmacogenetics; warfarin
Aims and objectives
Test the feasibility and validity of a handoff evaluation tool for nurses.
No validated tools exist to assess the quality of handoff communication during change of shift.
Prospective cohort study.
A standardised tool, the Handoff CEX, was developed based on the mini-CEX. The tool consisted of seven domains scored on a 1–9 scale. Nurse educators observed shift-to-shift handoff reports among nurses and evaluated both the provider and recipient of the report. Nurses participating in the report simultaneously evaluated each other as part of their handoff.
Ninety-eight evaluations were obtained from 25 reports. Scores ranged from 3–9 in all domains except communication and setting (4–9). Experienced (>five years) nurses received significantly higher mean scores than inexperienced (≤five years) nurses in all domains except setting and professionalism. Mean overall score for experienced nurses was 7·9 vs 6·9 for inexperienced nurses. External observers gave significantly lower scores than peer evaluators in all domains except setting. Mean overall score by external observers was 7·1 vs. 8·1 by peer evaluators. Participants were very satisfied with the evaluation (mean score 8·1).
A brief, structured handoff evaluation tool was designed that was well-received by participants, was felt to be easy to use without training, provided data about a wide range of communication competencies and discriminated well between experienced and inexperienced clinicians.
Relevance to clinical practice
This tool may be useful for educators, supervisors and practicing nurses to provide training, ongoing assessment and feedback to improve the quality of handoff.
communication; evaluation; handover; nurses; nursing; nursing education; transfer of care
To examine the association of anxiety and depression with pulmonary-specific symptoms of Chronic Obstructive Pulmonary Disease (COPD), and to determine the extent to which disease severity and functional capacity modify this association.
Patients (N = 162) enrolled in the INSPIRE-II study, an ongoing randomized, clinical trial of COPD patients and their caregivers who received either telephone-based coping skills training or education and symptom monitoring. Patients completed a psychosocial test battery including: Brief Fatigue Inventory, St. George’s Respiratory Questionnaire, UCSD Shortness of Breath Questionnaire, State-Trait Anxiety Inventory, and Beck Depression Inventory. Measures of disease severity and functional capacity (i.e., FEV1 and six-minute walk test) were also obtained.
After covariate adjustment, higher anxiety and depression levels were associated with greater fatigue levels (ps < .001, ΔR2 = 0.16 and 0.29, respectively), shortness of breath (ps < .001, ΔR2 = 0.12 and 0.10), and frequency of COPD symptoms (ps < .001, ΔR2 = 0.11 and 0.13). In addition, functional capacity was a moderator of anxiety and pulmonary-specific COPD symptoms. The association between anxiety and shortness of breath (p = 0.009) and frequency of COPD symptoms (p = 0.02) was greater among patients with lower functional capacity.
Anxiety and depression were associated with higher levels of fatigue, shortness of breath, and frequency of COPD symptoms. It is important for clinicians to be aware of the presence of anxiety and depression in COPD patients, which appears to correlate with pulmonary-specific COPD symptoms, especially in patients with lower functional capacity. Prospective design studies are needed to elucidate the causal relationships between anxiety and depression and pulmonary-specific symptoms in COPD patients.
anxiety; depression; COPD
Blood pressure (BP) is a heritable determinant of risk for cardiovascular disease (CVD). To investigate genetic associations with systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP) and pulse pressure (PP), we genotyped ∼50 000 single-nucleotide polymorphisms (SNPs) that capture variation in ∼2100 candidate genes for cardiovascular phenotypes in 61 619 individuals of European ancestry from cohort studies in the USA and Europe. We identified novel associations between rs347591 and SBP (chromosome 3p25.3, in an intron of HRH1) and between rs2169137 and DBP (chromosome1q32.1 in an intron of MDM4) and between rs2014408 and SBP (chromosome 11p15 in an intron of SOX6), previously reported to be associated with MAP. We also confirmed 10 previously known loci associated with SBP, DBP, MAP or PP (ADRB1, ATP2B1, SH2B3/ATXN2, CSK, CYP17A1, FURIN, HFE, LSP1, MTHFR, SOX6) at array-wide significance (P < 2.4 × 10−6). We then replicated these associations in an independent set of 65 886 individuals of European ancestry. The findings from expression QTL (eQTL) analysis showed associations of SNPs in the MDM4 region with MDM4 expression. We did not find any evidence of association of the two novel SNPs in MDM4 and HRH1 with sequelae of high BP including coronary artery disease (CAD), left ventricular hypertrophy (LVH) or stroke. In summary, we identified two novel loci associated with BP and confirmed multiple previously reported associations. Our findings extend our understanding of genes involved in BP regulation, some of which may eventually provide new targets for therapeutic intervention.
Aspirin or dual antiplatelet therapy (DAPT) with aspirin and clopidogrel is standard therapy for patients at increased risk for cardiovascular events. However, the genetic determinants of variable response to aspirin (alone and in combination with clopidogrel) are not known.
Methods and Results
We measured ex-vivo platelet aggregation before and after DAPT in individuals (n=565) from the Pharmacogenomics of Antiplatelet Intervention (PAPI) Study and conducted a genome-wide association study (GWAS) of drug response. Significant findings were extended by examining genotype and cardiovascular outcomes in two independent aspirin-treated cohorts: 227 percutaneous coronary intervention (PCI) patients, and 1,000 patients of the International VErapamil SR/trandolapril Study (INVEST) GENEtic Substudy (INVEST-GENES). GWAS revealed a strong association between single nucleotide polymorphisms on chromosome 1q23 and post-DAPT platelet aggregation. Further genotyping revealed rs12041331 in the platelet endothelial aggregation receptor-1 (PEAR1) gene to be most strongly associated with DAPT response (P=7.66×10−9). In Caucasian and African American patients undergoing PCI, A-allele carriers of rs12041331 were more likely to experience a cardiovascular event or death compared to GG homozygotes (hazard ratio = 2.62, 95%CI 0.96-7.10, P=0.059 and hazard ratio = 3.97, 95%CI 1.10-14.31, P=0.035 respectively). In aspirin-treated INVEST-GENES patients, rs12041331 A-allele carriers had significantly increased risk of myocardial infarction compared to GG homozygotes (OR=2.03, 95%CI 1.01-4.09, P=0.048).
Common genetic variation in PEAR1 may be a determinant of platelet response and cardiovascular events in patients on aspirin, alone and in combination with clopidogrel.
Clinical Trial Registration Information
clinicaltrials.gov; Identifiers: NCT00799396 and NCT00370045
pharmacogenomics; platelets; percutaneous coronary intervention; PEAR1; CYP2C19
Single-nucleotide polymorphisms (SNPs) in NEDD4L may influence the ability of the NEDD4L protein to reduce epithelial sodium channel expression. A variant in NEDD4L, rs4149601, was associated with antihypertensive response and cardiovascular outcomes during treatment with thiazide diuretics and β-blockers in a Swedish population. We sought to further evaluate associations between NEDD4L polymorphisms, blood pressure response and cardiovascular outcomes with thiazide diuretics and β-blockers.
Four SNPs, rs4149601, rs292449, rs1008899 and rs75982813, were genotyped in 767 patients from the Pharmacogenomic Evaluation of Antihypertensive Responses (PEAR) clinical trial and association was assessed with blood pressure response to hydrochlorothiazide and atenolol. One SNP, rs4149601, was also genotyped in 1345 patients from the International Verapmil SR Trandolapril Study (INVEST), and association was examined with adverse cardiovascular outcomes relative to hydrochlorothiazide treatment.
Significant associations or trends were found between rs4149601, rs292449, rs75982813 and rs1008899 and decreases in blood pressure in whites on hydrochlorothiazide, and a significant association was observed with increasing copies of the GC rs4149601-rs292449 haplotype and greater blood pressure response to hydrochlorothiazide in whites (P = 0.0006 and 0.006, SBP and DBP, respectively). Significant associations were also seen with rs4149601 and an increased risk for adverse cardiovascular outcomes in whites not treated with hydrochlorothiazide [P = 0.022, odds ratio (95% confidence interval) = 10.65 (1.18–96.25)].
NEDD4L rs4149601, rs292449 and rs75982813 may be predictors for blood pressure response to hydrochlorothiazide in whites, and NEDD4L rs4149601 may be a predictor for adverse cardiovascular outcomes in whites not treated with hydrochlorothiazide.
epithelial sodium channel; hypertension; International Verapamil SR Trandolapril Study; neural precursor cell expressed developmentally down-regulated 4 like; Pharmacogenomic Evaluation of Antihypertensive Responses; pharmacogenetics
To date, 39 SNPs have been associated with blood pressure (BP) or hypertension (HTN) in genome-wide association studies (GWAS) in Caucasians. Our hypothesis is that the loci/SNPs associated with BP/HTN are also associated with BP response to antihypertensive drugs.
Methods and Results
We assessed the association of these loci with BP response to atenolol or hydrochlorothiazide monotherapy in 768 hypertensive participants in the Pharmacogenomics Responses of Antihypertensive Responses (PEAR) study. Linear regression analysis was performed in Caucasians for each SNP in an additive model adjusting for baseline BP, age, gender and principal components for ancestry. Genetic scores were constructed to include SNPs with nominal associations and empirical p values were determined by permutation test. Genotypes of 37 loci were obtained from Illumina 50K cardiovascular or Omni1M GWAS chips. In Caucasians, no SNPs reached Bonferroni-corrected alpha of 0.0014, six reached nominal significance (p<0.05) and 3 were associated with atenolol BP response at p < 0.01. The genetic score of the atenolol BP lowering alleles was associated with response to atenolol (p =3.3*10−6 for SBP; p=1.6*10−6 for DBP). The genetic score of the HCTZ BP lowering alleles was associated with response to HCTZ (p = 0.0006 for SBP; p = 0.0003 for DBP). Both risk score p values were < 0.01 based on the empirical distribution from the permutation test.
These findings suggest selected signals from hypertension GWAS may predict BP response to atenolol and HCTZ when assessed through risk scoring.
beta-blocker; diuretics; hypertension; pharmacogenetics; polymorphisms blood pressure
A recent genome-wide analysis discovered an association between a haplotype (from rs317689/rs315135/rs7297610) on Chromosome 12q15 and blood pressure response to hydrochlorothiazide in African-Americans. Our aim was to replicate this association and investigate possible functional mechanisms. We observed similar associations between this haplotype and hydrochlorothiazide response in an independent sample of 746 Caucasians and African-Americans randomized to hydrochlorothiazide or atenolol treatment. The haplotype association was driven by variation at rs7297610, where C/C genotypes were associated with greater mean (systolic: 3.4mmHg, P=0.0275; diastolic: 2.5mmHg, P=0.0196) responses to hydrochlorothiazide vs. T-allele carriers. Such an association was absent in atenolol-treated participants, supporting this as hydrochlorothiazide-specific. Expression analyses in hydrochlorothiazide-treated African-Americans showed differential leukocyte YEATS4 expression between rs7297610 genotype groups at baseline (P=0.024), and reduced expression in C/C genotypes (P=0.009), but not in T-carriers. Our data confirm previous genome-wide findings at 12q15 and suggest differential YEATS4 expression could underpin rs7297610-associated HCTZ response variability, which may have future implications for guiding thiazide treatment.
hydrochlorothiazide; hypertension; pharmacogenomics; blood pressure; YEATS4; diuretics
A simplified method to determine clarithromycin concentrations in human plasma using protein precipitation in a 96-well plate and liquid chromatography tandem mass spectrometry was developed and validated. Plasma proteins were precipitated with acetonitrile and roxithromycin was used as the internal standard. After vortex-mixing and centrifugation, the supernatants were directly injected onto a Phenomenex Luna Phenyl-Hexyl column (50 × 2.0 mm I.D., 3μm). The mobile phase consisted of water and methanol (30:70; v/v) containing 0.1% formic acid and 5 mM ammonium acetate. The flow rate was 0.22 mL/min and the total run time (injection to injection) was less than 3 minutes. Detection of the analytes was achieved using positive ion electrospray tandem mass spectrometry in selected reaction monitoring (SRM) mode. The linear standard curve ranged from 100 to 5,000 ng/mL and the precision and accuracy (inter- and intrarun) were within 8.3% and 6.3%, respectively. The method was successfully used to determine clarithromycin concentrations in human plasma samples obtained from healthy subjects who were given clarithromycin 500 mg for three days. The method is rapid, simple, precise and directly applicable to clarithromycin pharmacokinetic studies.
clarithromycin; roxithromycin; protein precipitation; LC-MS; human plasma
Although the DASH (Dietary Approaches to Stop Hypertension) diet is an accepted non-pharmacologic treatment for hypertension, little is known about what patient characteristics affect dietary adherence and what level of adherence is needed to reduce blood pressure (BP).
To determine what factors predict dietary adherence and the extent to which dietary adherence is necessary to produce clinically meaningful BP reductions.
Ancillary study of the ENCORE trial-- a 16-week randomized clinical trial of diet and exercise.
Participants included 144 sedentary, overweight or obese adults (BMI’s 25-39.9 kg/m2) with high BP (systolic BP 130-159 and/or diastolic BP 85-99 mm Hg).
Patients were randomized to one of 3 groups: DASH diet alone (DASH-A), DASH diet plus weight management (DASH+WM), and Usual diet controls (UC).
Main outcome measures
Our primary outcomes were a composite index of adherence to the DASH diet and clinic BP.
Statistical analyses performed
General linear models were used to compare treatment groups on post-treatment adherence to the DASH diet. Linear regression was used to examine potential predictors of post-treatment DASH adherence. Analysis of covariance (ANCOVA) was used to examine the relation of adherence to the DASH diet and BP.
Participants in the DASH+WM (16.1 SBP [95% CI = 13.0, 19.2], 9.9 DBP [95% CI = 8.1, 11.6] mm Hg) and DASH+A (11.2 SBP [95% CI = 8.1, 14.3], 7.5 DBP [95% CI = 5.8, 9.3] mm Hg) groups showed significant reductions in BP in comparison with UC participants (3.4 SBP [95% CI = 0.4, 6.4], DBP 3.8 [95% CI = 2.2, 5.5] mm Hg). Greater post-treatment consumption of DASH foods was noted in both the DASH-A (M=6.20 [95% CI = 5.83, 6.57]) and DASH+WM groups (M=6.23 [95% CI = 5.88, 6.59]) compared to UC (M=3.66 [95% CI = 3.30, 4.01]) (p<.0001), and greater adherence to the DASH diet was associated with larger reductions in clinic SBP and DBP (p ≤.01). Only ethnicity predicted dietary adherence, with African Americans less adherent to the DASH diet compared to whites (4.68 [95% CI = 4.34, 5.03] v 5.83 [95% CI = 5.50, 6.11], p< .001).
Greater adherence to the DASH diet was associated with larger BP reductions independent of weight loss. African Americans were less likely to be adherent to the DASH dietary eating plan compared to whites, suggesting that culturally sensitive dietary strategies may be needed to improve adherence to the DASH diet.
Hypertension; DASH diet; Blood pressure; Adherence; Psychological testing; Non-pharmacological treatment
We sought to identify novel pharmacogenomic markers for HDL-C response to atenolol in participants with mild to moderate hypertension. We genotyped 768 hypertensive participants from the Pharmacogenomic Evaluation of Antihypertensive Responses (PEAR) study on the Illumina HumanCVD Beadchip. During PEAR, participants were randomized to receive atenolol or hydrochlorothiazide. Blood pressure and cholesterol levels were evaluated at baseline and after treatment. This study focused on participants treated with atenolol monotherapy. Association with atenolol induced HDL-C change was evaluated in 232 whites and 152 African Americans using linear regression. No SNPs achieved a Bonferroni corrected P-value. However, we identified 13 regions with consistent association across whites and African Americans. The most interesting of these regions were seven with prior associations with HDL-C, other metabolic traits, or functional implications in the lipid pathway: GALNT2, FTO, ABCB1, LRP5, STARD3NL, ESR1, and LIPC. Examples are rs2144300 in GALNT2 in whites (P=2.29x10-4, β=-1.85 mg/dL) and rs12595985 in FTO in African Americans (P=2.90x10-4, β=4.52 mg/dL), both with consistent regional association (P<0.05) in the other race group. Additionally, baseline GALNT2 expression differed by rs2144300 genotype in whites (P=0.0279). In conclusion, we identified multiple gene regions associated with atenolol induced HDL-C change that were consistent across race groups, several with functional implications or prior associations with HDL-C.