Chapman, Arlene B.

Background There exists a wide interindividual variability in blood pressure ( BP ) response to β 1 ‐blockers. To identify the genetic determinants of this variability, we performed a pharmacogenomic genome‐wide meta‐analysis of genetic variants influencing β 1 ‐blocker BP response. Methods and Results Genome‐wide association analysis for systolic BP and diastolic BP response to β 1 ‐blockers from 5 randomized clinical trials consisting of 1254 patients with hypertension of European ancestry were combined in meta‐analysis and single nucleotide polymorphisms (SNPs) with P <10 −4 were tested for replication in 2 independent randomized clinical trials of β 1 ‐blocker–treated patients of European ancestry (n=1552). Regions harboring the replicated SNP s were validated in a β 1 ‐blocker–treated black cohort from 2 randomized clinical trials (n=315). A missense SNP rs28404156 in BST 1 was associated with systolic BP response to β 1 ‐blockers in the discovery meta‐analysis ( P =9.33×10 −5 , β=−3.21 mm Hg) and replicated at Bonferroni significance ( P =1.85×10 −4 , β=−4.86 mm Hg) in the replication meta‐analysis with combined meta‐analysis approaching genome‐wide significance ( P =2.18×10 −7 ). This SNP in BST 1 is in linkage disequilibrium with several SNP s with putative regulatory functions in nearby genes, including CD 38 , FBXL 5 , and FGFBP 1 , all of which have been implicated in BP regulation. SNP s in this genetic region were also associated with BP response in the black cohort. Conclusions Data from randomized clinical trials of 8 European ancestry and 2 black cohorts support the assumption that BST 1 containing locus on chromosome 4 is associated with β 1 ‐blocker BP response. Given the previous associations of this region with BP , this is a strong candidate region for future functional studies and potential use in precision medicine approaches for BP management and risk prediction.

Abstractβ‐Blockers’ heart rate (HR)‐lowering effect is an important determinant of the effectiveness for this class of drugs, yet it is variable among β‐blocker–treated patients. To date, genetic studies have revealed several genetic signals associated with HR response to β‐blockers. However, these genetic signals have not been consistently replicated across multiple independent cohorts. Here we sought to use data from 3 hypertension clinical trials to validate single‐nucleotide polymorphisms (SNPs) previously associated with the HR response to β‐blockers. Using linear regression analysis, we investigated the effects of 6 SNPs in 3 genes, including ADRB1, ADRB2, and GNB3, relative to the HR response following β‐blocker used in the PEAR (n = 757), PEAR‐2 (n = 368), and INVEST (n = 1401) trials, adjusting for baseline HR, age, sex, and ancestry. Atenolol was used in PEAR and INVEST, and metoprolol was used in PEAR‐2. We found that rs1042714 and rs1042713 in ADRB2 were significantly associated with HR response to both β‐blockers in whites (rs1042714 C‐allele carriers, meta‐analysis β = –0.95 beats per minute [bpm], meta‐analysis P = 3×10–4; rs1042713 A‐allele carriers, meta‐analysis β = –1.15 bpm, meta‐analysis P = 2×10–3). In conclusion, the results of our analyses provide strong evidence to support the hypothesis that rs1042714 and rs1042713 in the ADRB2 gene are important predictors of HR response to cardioselective β‐blockade in hypertensive patient cohorts.

European Americans (EA) have a better antihypertensive response to β‐blockers when compared with African Americans, albeit with some variability. We undertook a genomewide association study to elucidate the underlying genetic determinants in EA contributing to this variability in blood pressure (BP) response. A discovery genomewide association study of change in BP post–metoprolol treatment was performed in EA participants (n = 201) from the Pharmacogenomic Evaluation of Antihypertensive Responses‐2 (PEAR‐2) study and tested for replication in the atenolol‐treated EA from the PEAR study (n = 233). Rs294610 in the FGD5, which encodes for FYVE, RhoGEF and PH Domain Containing 5, (expression quantitative trait loci for FGD5 in the small intestine) was significantly associated with increased diastolic BP response to β‐blockers in the PEAR‐2 study (P = 3.41 × 10−6, β = −2.70) and replicated (P = 0.01, β = −1.17) in the PEAR study. Post–meta‐analysis of these studies, an additional single nucleotide polymorphism rs45545233 in the SLC4A1, encoding for Solute Carrier Family 4 Member 1, (expression quantitative trait loci for dual specificity phosphatase 3 in the artery tibial) was identified that was significantly associated with a poor response to β‐blockers (P = 3.43 × 10−6, β = 4.57) and was replicated in the atenolol add‐on cohort (P = 0.007, β = 4.97). We identified variants in FGD5 and SLC4A1, which have been previously cited as candidate genes for hypertension, to be associated with a β‐blocker BP response in EA. Further elucidation is warranted of the underlying mechanisms of these variants and genes by which they influence the BP response to β‐blockers.

Background Thiazide and thiazide‐like diuretics are first‐line medications for treating uncomplicated hypertension. However, their use has been associated with adverse metabolic events, including hyperglycemia and incident diabetes mellitus, with incompletely understood mechanisms. Our goal was to identify genomic variants associated with thiazide‐like diuretic/chlorthalidone‐induced glucose change. Methods and Results Genome‐wide analysis of glucose change after treatment with chlorthalidone was performed by race among the white (n=175) and black (n=135) participants from the PEAR ‐2 (Pharmacogenomic Evaluation of Antihypertensive Responses‐2). Single‐nucleotide polymorphisms with P <5×10 −8 were further prioritized using in silico analysis based on their expression quantitative trait loci function. Among blacks, an intronic single‐nucleotide polymorphism (rs9943291) in the HMGCS 2 was associated with increase in glucose levels following chlorthalidone treatment (ß=12.5; P =4.17×10 −8 ). G‐allele carriers of HMGCS 2 had higher glucose levels (glucose change=+16.29 mg/dL) post chlorthalidone treatment compared with noncarriers of G allele (glucose change=+2.80 mg/dL). This association was successfully replicated in an independent replication cohort of hydrochlorothiazide‐treated participants from the PEAR study (ß=5.54; P =0.023). A meta‐analysis of the 2 studies was performed by race in Meta‐Analysis Helper, where this single‐nucleotide polymorphism, rs9943291, was genome‐wide significant with a meta‐analysis P value of 3.71×10 −8 . HMGCS 2 , a part of the HMG ‐CoA synthase family, is important for ketogenesis and cholesterol synthesis pathways that are essential in glucose homeostasis. Conclusions These results suggest that HMGCS 2 is a promising candidate gene involved in chlorthalidone and Hydrochlorothiazide (HCTZ)‐induced glucose change. This may provide insights into the mechanisms involved in thiazide‐induced hyperglycemia that may ultimately facilitate personalized approaches to antihypertensive selection for hypertension treatment. Clinical Trial Registration URL : http://www.clinicaltrials.gov . Unique identifiers: NCT 00246519 and NCT 01203852.

Background Resistant hypertension (RHTN), defined by lack of blood pressure (BP) control despite treatment with at least 3 antihypertensive drugs, increases cardiovascular risk compared with controlled hypertension. Yet, there are few data on genetic variants associated with RHTN. Methods and Results We used a gene‐centric array containing ≈50 000 single‐nucleotide polymorphisms (SNPs) to identify polymorphisms associated with RHTN in hypertensive participants with coronary artery disease (CAD) from INVEST‐GENES (the INnternational VErapamil‐SR Trandolapril STudy—GENEtic Substudy). RHTN was defined as BP≥140/90 on 3 drugs, or any BP on 4 or more drugs. Logistic regression analysis was performed in European Americans (n=904) and Hispanics (n=837), using an additive model adjusted for age, gender, randomized treatment assignment, body mass index, principal components for ancestry, and other significant predictors of RHTN. Replication of the top SNP was conducted in 241 European American women from WISE (Women's Ischemia Syndrome Evaluation), where RHTN was defined similarly. To investigate the functional effect of rs12817819, mRNA expression was measured in whole blood. We found ATP2B1 rs12817819 associated with RHTN in both INVEST European Americans ( P ‐value=2.44×10 −3 , odds ratio=1.57 [1.17 to 2.01]) and INVEST Hispanics ( P =7.69×10 −4 , odds ratio=1.76 [1.27 to 2.44]). A consistent trend was observed at rs12817819 in WISE, and the INVEST‐WISE meta‐analysis result reached chip‐wide significance ( P =1.60×10 −6 , odds ratio=1.65 [1.36 to 1.95]). Expression analyses revealed significant differences in ATP2B1 expression by rs12817819 genotype. Conclusions The ATP2B1 rs12817819 A allele is associated with increased risk for RHTN in hypertensive participants with documented CAD or suspected ischemic heart disease. Clinical Trial Registration URL: www.clinicaltrials.gov ; Unique identifiers: NCT00133692 (INVEST), NCT00000554 (WISE).

Study ObjectiveTo develop and validate a predictive model for glucose change and risk for new‐onset impaired fasting glucose in hypertensive participants following treatment with atenolol or hydrochlorothiazide (HCTZ).DesignRandomized multicenter clinical trial.PatientsA total of 735 white or African‐American men and women with uncomplicated hypertension.Measurements and Main ResultsPharmacogenomic Evaluation of Antihypertensive Responses (PEAR) is a randomized clinical trial to assess the genetic and nongenetic predictors of blood pressure response and adverse metabolic effects following treatment with atenolol or HCTZ. To develop and validate predictive models for glucose change, PEAR participants were randomly divided into a derivation cohort of 367 and a validation cohort of 368. Linear and logistic regression modeling were used to build models of drug‐associated glucose change and impaired fasting glucose (IFG), respectively, in the derivation cohorts. These models were then evaluated in the validation cohorts. For glucose change after atenolol or HCTZ treatment, baseline glucose was a significant (p<0.0001) predictor, explaining 13% of the variability in glucose change after atenolol and 12% of the variability in glucose change after HCTZ. Baseline glucose was also the strongest and most consistent predictor (p<0.0001) for development of IFG after atenolol or HCTZ monotherapy. The area under the receiver operating curve was 0.77 for IFG after atenolol and 0.71 after HCTZ treatment, respectively.ConclusionBaseline glucose is the primary predictor of atenolol or HCTZ‐associated glucose increase and development of IFG after treatment with either drug.

AbstractObjectiveElevations in uric acid (UA) and the associated hyperuricaemia are commonly observed secondary to treatment with thiazide diuretics. We sought to identify novel single nucleotide polymorphisms (SNPs) associated with hydrochlorothiazide (HCTZ)‐induced elevations in UA and hyperuricaemia.MethodsA genome‐wide association study of HCTZ‐induced changes in UA was performed in Caucasian and African American participants from the pharmacogenomic evaluation of antihypertensive responses (PEAR) study who were treated with HCTZ monotherapy. Suggestive SNPs were replicated in Caucasians and African Americans from the PEAR study who were treated with HCTZ add‐on therapy. Replicated regions were followed up through expression and pathway analysis.ResultsFive unique gene regions were identified in African Americans (LUC7L2, ANKRD17/COX18, FTO, PADI4 and PARD3B), and one region was identified in Caucasians (GRIN3A). Increases in UA of up to 1.8 mg dL−1 were observed following HCTZ therapy in individuals homozygous for risk alleles, with heterozygotes displaying an intermediate phenotype. Several risk alleles were also associated with an increased risk of HCTZ‐induced clinical hyperuricaemia. A composite risk score, constructed in African Americans using the ‘top’ SNP from each gene region, was strongly associated with HCTZ‐induced UA elevations (P = 1.79 × 10−7) and explained 11% of the variability in UA response. Expression studies in RNA from whole blood revealed significant differences in expression of FTO by rs4784333 genotype. Pathway analysis showed putative connections between many of the genes identified through common microRNAs.ConclusionSeveral novel gene regions were associated with HCTZ‐induced UA elevations in African Americans (LUC7L2, COX18/ANKRD17, FTO, PADI4 and PARD3B), and one region was associated with these elevations in Caucasians (GRIN3A).

Study ObjectiveTo assess the relationship of the 33 single nucleotide polymorphisms (SNPs) previously associated with fasting glucose in Caucasians in genome‐wide association studies (GWAS) with glucose response to antihypertensive drugs shown to increase risk for hyperglycemia and diabetes.DesignRandomized, multicenter clinical trial.PatientsA total of 456 Caucasian men and women with uncomplicated hypertension.Measurements and Main ResultsThe Pharmacogenomic Evaluation of Antihypertensives Responses study evaluated blood pressure and glucose response in uncomplicated hypertensive patients randomized to either atenolol or hydrochlorothiazide (HCTZ) monotherapy, followed by combination therapy with both agents. Association of these SNPs with atenolol‐ or HCTZ‐induced glucose response was evaluated in 456 Caucasian patients using linear regression adjusting for age, sex, body mass index, baseline glucose, baseline insulin, and principal component for ancestry.The SNP rs340874 in the 5′ region of PROX1 gene was significantly associated with atenolol‐induced glucose change (p=0.0013). Participants harboring the C allele of this SNP had greater glucose elevation after approximately 9 weeks of atenolol monotherapy (β = +2.39 mg/dl per C allele), consistent with the direction of effect in fasting glucose GWAS, that showed the C allele is associated with higher fasting glucose.ConclusionThese data suggest that PROX1 SNP rs340874, discovered in fasting glucose GWAS, may also be a pharmacogenetic risk factor for antihypertensive‐induced hyperglycemia. β‐blockers and thiazides may interact with genetic risk factors to increase risk for dysglycemia and diabetes.

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, α 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 4-study meta-analysis P value achieved genome-wide significance ( P =3.3×10 −8 ). Systolic or diastolic blood pressure responses were consistently greater in carriers of the rs16960228 A allele than in GG homozygotes (>4/4 mm Hg) 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 3-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.