beta-adrenergic receptor gene polymorphisms and beta-blocker treatment outcomes in hypertension

Genetic polymorphisms influencing antihypertensive drug responses

Hypertension is a major contributor to cardiovascular disease and its associated morbidity and mortality. The low efficacy observed with some anti-hypertensive therapies has been attributed partly to inter-individual genetic variability. This paper reviews the major findings regarding these genetic variabilities that modulate responses to anti-hypertensive therapies such as angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blockers (ARBs), diuretics, calcium channel blockers (CCBs) and β-adrenoceptor blockers. The importance of studying these genetic polymorphisms stems from the goal to optimise anti-hypertensive therapy for each individual patient, aiming for the highest efficacy and lowest risk of adverse effects. It is important to recognise that environmental and epigenetic factors can contribute to the observed variations in drug responses. Owing to the multigenic and multifactorial nature of drug responses, further research is crucial for translating these findings into clinical practice and the establishment of reliable recommendations.

Pharmacogenetic and microRNA mechanisms of beta blocker use on bone

Motivated by studies showing an association between beta blocker (BB) use and positive bone outcomes, a pilot randomized control trial (RCT) was performed at the Mayo Clinic which randomized postmenopausal women to placebo, propranolol (40 or 80 mg twice daily), atenolol (50 mg/day), or nebivolol (5 mg/day) to determine changes in bone turnover markers (BTMs) and in bone mineral density (BMD) over 20 weeks. Pharmacogenetic effects and microRNA-mediated mechanisms involving beta adrenergic receptor and related genes have previously been found. We sought to validate these effects and discover new candidates in an ancillary study to the pilot clinical trial. We genotyped all participants and performed microRNA (miRNA) sequencing at baseline and at 20 weeks for 24 participants from the atenolol or placebo groups. We discovered several variants in ADRB1, ADRB2, and HDAC4 which showed significant pharmacogenetic effects with BMD at multiple sites and with BTMs. Our miRNA results showed a significant treatment effect for miR-19a-3p over time with atenolol use in the low-responder group compared to placebo. Overall, the longitudinal miRNA analysis showed a large number of miRNAs which were up-regulated over the trial in the low responders but not the high responders compared to placebo, of which miR-19a-3p was one example. Finally, we compared the response to atenolol treatment for cardiovascular traits (pulse, blood pressure) with the response for the bone resorption marker, CTX, and found a largely independent effect. Our results have implications for personalized therapy and for understanding mechanisms of BB treatment effect on bone.

Clinical Pharmacogenetics Implementation Consortium Guideline (CPIC) for CYP2D6, ADRB1, ADRB2, ADRA2C, GRK4, and GRK5 Genotypes and Beta-Blocker Therapy

Beta-blockers are widely used medications for a variety of indications, including heart failure, myocardial infarction, cardiac arrhythmias, and hypertension. Genetic variability in pharmacokinetic (e.g., CYP2D6) and pharmacodynamic (e.g., ADRB1, ADRB2, ADRA2C, GRK4, GRK5) genes have been studied in relation to beta-blocker exposure and response. We searched and summarized the strength of the evidence linking beta-blocker exposure and response with the six genes listed above. The level of evidence was high for associations between CYP2D6 genetic variation and both metoprolol exposure and heart rate response. Evidence indicates that CYP2D6 poor metabolizers experience clinically significant greater exposure and lower heart rate in response to metoprolol compared with those who are not poor metabolizers. Therefore, we provide therapeutic recommendations regarding genetically predicted CYP2D6 metabolizer status and metoprolol therapy. However, there was insufficient evidence to make therapeutic recommendations for CYP2D6 and other beta-blockers or for any beta-blocker and the other five genes evaluated (updates at www.cpicpgx.org).

CHL-DTI: A Novel High-Low Order Information Convergence Framework for Effective Drug-Target Interaction Prediction

Recognizing drug-target interactions (DTI) stands as a pivotal element in the expansive field of drug discovery. Traditional biological wet experiments, although valuable, are time-consuming and costly as methods. Recently, computational methods grounded in network learning have demonstrated great advantages by effective topological feature extraction and attracted extensive research attention. However, most existing network-based learning methods only consider the low-order binary correlation between individual drug and target, neglecting the potential higher-order correlation information derived from multiple drugs and targets. High-order information, as an essential component, exhibits complementarity with low-order information. Hence, the incorporation of higher-order associations between drugs and targets, while adequately integrating them with the existing lower-order information, could potentially yield substantial breakthroughs in predicting drug-target interactions. We propose a novel dual channels network-based learning model CHL-DTI that converges high-order information from hypergraphs and low-order information from ordinary graph for drug-target interaction prediction. The convergence of high-low order information in CHL-DTI is manifested in two key aspects. First, during the feature extraction stage, the model integrates both high-level semantic information and low-level topological information by combining hypergraphs and ordinary graph. Second, CHL-DTI fully fuse the innovative introduced drug-protein pairs (DPP) hypergraph network structure with ordinary topological network structure information. Extensive experimentation conducted on three public datasets showcases the superior performance of CHL-DTI in DTI prediction tasks when compared to SOTA methods. The source code of CHL-DTI is available at https://github.com/UPCLyy/CHL-DTI .

Receptor Pharmacogenomics: Deciphering Genetic Influence on Drug Response

The paradigm "one drug fits all" or "one dose fits all" will soon be challenged by pharmacogenetics research and application. Drug response-efficacy or safety-depends on interindividual variability. The current clinical practice does not include genetic screening as a routine procedure and does not account for genetic variation. Patients with the same illness receive the same treatment, yielding different responses. Integrating pharmacogenomics in therapy would provide critical information about how a patient will respond to a certain drug. Worldwide, great efforts are being made to achieve a personalized therapy-based approach. Nevertheless, a global harmonized guideline is still needed. Plasma membrane proteins, like receptor tyrosine kinase (RTK) and G protein-coupled receptors (GPCRs), are ubiquitously expressed, being involved in a diverse array of physiopathological processes. Over 30% of drugs approved by the FDA target GPCRs, reflecting the importance of assessing the genetic variability among individuals who are treated with these drugs. Pharmacogenomics of transmembrane protein receptors is a dynamic field with profound implications for precision medicine. Understanding genetic variations in these receptors provides a framework for optimizing drug therapies, minimizing adverse reactions, and advancing the paradigm of personalized healthcare.

Association of Antihypertensive Drug-Related Gene Polymorphisms with Stroke in the Chinese Hypertensive Population

Background

Antihypertensive therapy is crucial for preventing stroke in hypertensive patients. However, the efficacy of antihypertensive therapy varies across individuals, partially due to therapy-related genetic variations among individuals. We investigated the association of antihypertensive drug-related gene polymorphism with stroke in patients with hypertension.

Methods

Demographic information, medication, and outcome data were obtained from a hypertensive patient management system, and a PCR fluorescence probe technique was used to detect 7 gene polymorphic loci (CYP2D6∗10, ADRB1, CYP2C9∗3, AGTR1, ACE, CYP3A5∗3, and NPPA), and these loci were compared between patients with and without stroke. Logistic regression was performed to analyze the association of these genetic variations with stroke risk in hypertensive patients while controlling for potential factors.

Results

The prevalence of stroke in the hypertensive population in Changsha County of Hunan Province was 2.75%. The mutation frequencies of ADRB1 (1165G > C), CYP2D6∗10, CYP2C9∗3, AGTR1 (1166A > C), ACE (I/D), NPPA (2238T > C), and CYP3A5∗3 were 74.43%, 57.23%, 4.26%, 5.71%, 31.62%, 1.17%, and 69.58%, respectively. Univariate analysis revealed that ADRB1 polymorphism was associated with stroke (χ2 = 8.659, P < 0.05), with a higher stroke risk in the CC group than in the GC and GG groups (GC + GG). Multivariate unconditional logistic regression analysis showed that the CC genotype in ADRB1 (vs. the GC + GG genotype) was associated with an increased risk of stroke [odds ratio (OR) = 1.184, P<0.05] in hypertensive patients. No association was observed between CYP2D6∗10, CYP2C9∗3, AGTR1 (1166A > C), ACE (I/D), CYP3A5∗3, and NPPA (2238T > C) polymorphisms and stroke.

Conclusions

ADRB1 (1165G > C) gene polymorphism is associated with the risk of stroke in Chinese hypertensive patients. The CC genotype is correlated with a higher risk of stroke than the GC + GG genotype.

Genetic Variants of Adrenoceptors

Adrenoceptors are class A G-protein-coupled receptors grouped into three families (α1-, α2-, and β-adrenoceptors), each one including three members. All nine corresponding adrenoceptor genes display genetic variation in their coding and adjacent non-coding genomic region. Coding variants, i.e., nucleotide exchanges within the transcribed and translated receptor sequence, may result in a difference in amino acid sequence thus altering receptor function and signaling. Such variants have been intensely studied in vitro in overexpression systems and addressed in candidate-gene studies for distinct clinical parameters. In recent years, large cohorts were analyzed in genome-wide association studies (GWAS), where variants are detected as significant in context with specific traits. These studies identified two of the in-depth characterized 18 coding variants in adrenoceptors as repeatedly statistically significant genetic risk factors - p.Arg389Gly in the β1- and p.Thr164Ile in the β2-adrenoceptor, along with 56 variants in the non-coding regions adjacent to the adrenoceptor gene loci, the functional role of which is largely unknown at present. This chapter summarizes current knowledge on the two coding variants in adrenoceptors that have been consistently validated in GWAS and provides a prospective overview on the numerous non-coding variants more recently attributed to adrenoceptor gene loci.

Comparison between the ECG Outcomes of Metoprolol and Bisoprolol

BACKGROUND

Beta-blockers are essential agents in the management of cardiovascular diseases, such as heart failure, acute myocardial infarction (MI), and cardiac arrhythmias. However, there are diurnal variations in the cardioprotective effects of the subgroups as a result of their different pharmacokinetic, pharmacodynamic, and pharmacogenetic profiles.

OBJECTIVES

We aimed to compare metoprolol and bisoprolol in terms of electrocardiogram (ECG) outcomes.

METHODS

A retrospective cross-sectional study was conducted at Prince Sultan Cardiac Center. The trial included 404 patients who met the inclusion criteria (204 in the metoprolol arm and 200 in the bisoprolol arm). Using case record forms that had already been created, information, such as patient demographics, medical histories, and treatment histories, was taken from their medical files. The most recent ECG records were also gathered. The ethical approval for this study was obtained from Qassim ethical committee (approval number: 45-44-902).

RESULTS

There was no significant difference found between the patients in both arms in terms of baseline characteristics, age, or sex.

CONCLUSION

In this retrospective cross-sectional study, we have compared the effects of metoprolol and bisoprolol beta blockers on ECG changes. The findings have indicated no difference between metoprolol and bisoprolol groups in terms of all ECG readings, particularly PR/ms, QTC-ms, and ventricular rate. Further studies are required to confirm these findings.

Genetic polymorphisms in ADRB1, ADRB2 and CYP2D6 genes and response to beta-blockers in patients with acute coronary syndrome

Betablockers (BBs) are prescribed for ischaemia in patients with acute coronary syndrome (ACS). In Spain, bisoprolol and carvedilol are the most prescribed BBs, but patients often had to discontinue them due to adverse effects. Single nucleotide polymorphisms (SNPs) in ADRB1, ADRB2 and CYP2D6 genes have strong evidence of pharmacogenetic association with BBs in heart failure or hypertension, but the evidence in ACS is limited. Therefore, our study focuses on investigating how these genes influence the response to BBs in ACS patients. We analysed the association between SNPs in ADRB1 Gly389Arg (rs1801253) and Ser49Gly (rs1801252), ADRB2 Gly16Arg (rs1042713) and Glu27Gln (rs1042714), and CYP2D* 6 (*2- rs1080985, *4- rs3892097, *10 - rs1065852) and the occurrence of bradycardia/hypotension events during one year of follow-up. We performed an observational study and included 285 ACS-PCI-stent patients. A first analysis including patients treated with bisoprolol and a second analysis including patients treated with other BBs were performed. We found that the presence of the G allele (Glu) of the ADRB2 gene (rs1042714; Glu27Gln) conferred a protective effect against hypotension-induced by BBs; OR (CI 95%) = 0,14 (0,03-0,60), p < 0.01. The ADRB2 (rs1042713; Gly16Arg) GG genotype could also prevent hypotensive events; OR (CI 95%) = 0.49 (0.28-0.88), p = 0015. SNPs in ADRB1 and CYP2D6 * 2, CYP2D6 * 4 weren´t associated with primary events. The effect of CYP2D6 * 10 does not seem to be relevant for the response to BBs. According to our findings, SNPs in ADRB2 (rs1042713, rs1042714) could potentially affect the response and tolerance to BBs in ACS-patients. Further studies are necessary to clarify the impact of ADRB2 polymorphisms.

β1-adrenergic receptor polymorphisms: a possible genetic predictor of bisoprolol response in acute coronary syndrome

Aim

To investigate the association between beta1-adrenergic receptor (ADRB1) polymorphisms and response to bisoprolol treatment in beta-blocker naive patients with acute coronary syndrome (ACS).

Patients & methods

Seventy-seven patients received bisoprolol for four weeks. Blood pressure and heart rate were measured at baseline and during treatment. TaqMan allelic discrimination method was utilized for ADRB1 Ser49Gly and Arg389Gly genotyping.

Results

Arg389Arg carriers showed greater reductions in systolic and diastolic blood pressure (-8.5% ± 7.8% vs -0.76% ± 8.7%, p = 0.000218), and (-9.5% ± 9.7% vs -0.80% ± 11.5%, p = 0.000149), respectively, compared with Gly389 carriers. No statistical difference was found for study's outcomes based on codon 49.

Conclusion

Arg389Gly polymorphism is a promising bisoprolol response predictor in ACS patients.

Cardiovascular precision medicine - A pharmacogenomic perspective

Precision medicine envisages the integration of an individual's clinical and biological features obtained from laboratory tests, imaging, high-throughput omics and health records, to drive a personalised approach to diagnosis and treatment with a higher chance of success. As only up to half of patients respond to medication prescribed following the current one-size-fits-all treatment strategy, the need for a more personalised approach is evident. One of the routes to transforming healthcare through precision medicine is pharmacogenomics (PGx). Around 95% of the population is estimated to carry one or more actionable pharmacogenetic variants and over 75% of adults over 50 years old are on a prescription with a known PGx association. Whilst there are compelling examples of pharmacogenomic implementation in clinical practice, the case for cardiovascular PGx is still evolving. In this review, we shall summarise the current status of PGx in cardiovascular diseases and look at the key enablers and barriers to PGx implementation in clinical practice.

Chemical Synthesis, Safety and Efficacy of Antihypertensive Candidate Drug 221s (2,9)

Hypertension is the main risk factor of cardiovascular and cerebrovascular diseases. In this paper, a novel compound known as 221s (2,9), which includes tanshinol, borneol and a mother nucleus of ACEI, was synthesized by condensation esterification, deprotection, amidation, deprotection, and amidation, with borneol as the initial raw material, using the strategy of combinatorial molecular chemistry. The structure of the compound was confirmed by ¹H NMR, ¹³C NMR, and high-resolution mass spectrometry, with a purity of more than 99.5%. The compound 221s (2,9) can significantly reduce the systolic and diastolic blood pressure of SHR rats by about 50 mmHg and 35 mmHg after 4 weeks of administration. The antihypertensive effect of 221s (2,9) is equivalent to that of captopril. The use of 221s (2,9) can reduce the content of Ren, Ang II and ACE in the serum of SHR rats, inhibit the RAAS and enhance the vascular endothelial function by upregulating the level of NO. Pathological studies in this area have shown that high dosage of 221s (2,9) can notably protect myocardial fibrosis in rats and reduce the degeneration and necrosis of myocardial fibers, inflammatory cell infiltration, and proliferation of fibrous tissue in the heart of rat. Therefore, the existing work provided a foundation for preclinical research and follow-up clinical research of 221s (2,9) as a new drug.

Influence of β1 Adrenergic Receptor Genotype on Longitudinal Measures of Left Ventricular Ejection Fraction and Responsiveness to ß-Blocker Therapy in Patients With Duchenne Muscular Dystrophy

The purpose of this study was to determine whether the longitudinal progression of decline in left ventricular ejection fraction (LVEF) in Duchenne muscular dystrophy (DMD) patients is moderated by ADRB1 genotype and whether the efficacy of ß-blocker therapy is influenced by genotype status. About 147 DMD patients (6-34 years.) were analyzed with a focus on β₁ adrenergic receptor (ADRB1) genotype variants. Patients were grouped by ADRB1 genotype resulting in Gly389 patients and Arg389 patients. A generalized additive mixed effects model was used to examine differences in the nonlinear trend of LVEF across patient ages between genotype groups and for ß-blocker use. Both genotype groups displayed a progressive decline in LVEF starting around the mean age of ambulation loss (~12 years). However, there was no difference between genotype groups in the progression of decline in LVEF. There was a significant effect of ß-blocker use on longitudinal LVEF, wherein patients on ß-blockers had systematically lower LVEF when compared to patients not on ß-blockers. However, the effect of ß-blocker therapy on LVEF was not affected by ADRB1 genotype. The current study did not demonstrate an influence of patient ADRB1 genotype on longitudinal LVEF in our cohort. Despite previous literature suggesting a positive influence of ß-blocker use on cardiac function in DMD patients and of an ADRB1 genotypic difference in responsiveness to ß-blocker use, we did not observe this in our cohort. Interestingly, our cohort did not demonstrate a positive influence of ß-blocker use on LVEF measures.

β1-receptor polymorphisms and junctional ectopic tachycardia in children after cardiac surgery

Junctional ectopic tachycardia (JET) is a potentially life-threatening postoperative arrhythmia in children with specific congenital heart defects and can contribute significantly to postoperative morbidity for at-risk populations. In adults, β1-adrenergic receptor (ADRB1) and β2-adrenergic receptor (ADRB2) genotypes have been associated with increased risk for arrhythmias. However, their association with arrhythmia risk in children is unknown. We aimed to test associations between ADRB1 and ADRB2 genotypes and postoperative JET in patients with congenital heart defects. Children who underwent cardiac surgery were genotyped for the ADRB1 p.Ser49Gly (rs1801252; c.145A>G), p.Arg389Gly (rs1801253; c.1165C>G), ADRB2 p.Arg16Gly (rs1042713; c.46A>G), and p.Glu27Gln (rs1042714; c.79G>C) polymorphisms. The occurrence of postoperative JET was assessed via cardiologist-interpreted electrocardiograms. Genotype associations with JET were analyzed via logistic regression, adjusted for clinical variables associated with JET, with separate analysis in patients not on a β-blocker. Of the 343 children included (median age 8 months, 53% boys, 69% European ancestry), 45 (13%) developed JET. The Arg389Arg genotype was not significantly associated with JET in the overall population (odds ratio [OR] = 1.96, 95% confidence interval [CI] = 0.96-4.03, p = 0.064), but was nominally associated in patients not taking a β-blocker (n = 324, OR = 2.25, 95% CI = 1.05-4.80. p = 0.034). None of the other variants were associated with JET. These data suggest that the ADRB1 Arg389Arg genotype may predict risk for JET following cardiac surgery in pediatric patients in the absence of β-blockade. Whether treatment with a β-blocker ameliorates this association requires further research.

Pharmacogenomics of Hypertension in CKD: The CKD-PGX Study

Background

Patients with CKD often have uncontrolled hypertension despite polypharmacy. Pharmacogenomic drug-gene interactions (DGIs) may affect the metabolism or efficacy of antihypertensive agents. We report changes in hypertension control after providing a panel of 11 pharmacogenomic predictors of antihypertensive response.

Methods

A prospective cohort with CKD and hypertension was followed to assess feasibility of pharmacogenomic testing implementation, self-reported provider utilization, and BP control. The analysis population included 382 subjects with hypertension who were genotyped for cross-sectional assessment of DGIs, and 335 subjects followed for 1 year to assess systolic BP (SBP) and diastolic BP (DBP).

Results

Most participants (58%) with uncontrolled hypertension had a DGI reducing the efficacy of one or more antihypertensive agents. Subjects with a DGI had 1.85-fold (95% CI, 1.2- to 2.8-fold) higher odds of uncontrolled hypertension, as compared with those without a DGI, adjusted for race, health system (safety-net hospital versus other locations), and advanced CKD (eGFR <30 ml/min). CYP2C9-reduced metabolism genotypes were associated with losartan response and uncontrolled hypertension (odds ratio [OR], 5.2; 95% CI, 1.9 to 14.7). CYP2D6-intermediate or -poor metabolizers had less frequent uncontrolled hypertension compared with normal metabolizers taking metoprolol or carvedilol (OR, 0.55; 95% CI, 0.3 to 0.95). In 335 subjects completing 1-year follow-up, SBP (-4.0 mm Hg; 95% CI, 1.6 to 6.5 mm Hg) and DBP (-3.3 mm Hg; 95% CI, 2.0 to 4.6 mm Hg) were improved. No significant difference in SBP or DBP change were found between individuals with and without a DGI.

Conclusions

There is a potential role for the addition of pharmacogenomic testing to optimize antihypertensive regimens in patients with CKD.

Genetic Polymorphism of beta1-adrenergic Receptors and the Effect on the Clinical Efficacy of beta-adrenoblockers

Beta-adrenergic blockers are a valuable class of cardiovascular drugs and are widely used in the treatment of arterial hypertension (AH), coronary heart disease, chronic heart failure (CHF), cardiac arrhythmias, significantly improving the prognosis of patients. However, the clinical efficacy of betablockers is largely dependent on the genetic polymorphism of beta1-adrenergic receptors (ADRB1). The aim of the review was a systematic analysis of scientific data from pharmacogenetic studies on the role of beta1-adrenergic receptor polymorphism in the clinical efficacy of beta-blockers in the treatment of hypertension, chronic heart failure, and atrial fibrillation. The results of clinical trials and meta-analyzes were used. Of greatest importance is the genetic polymorphism of beta1-adrenergic receptors of two loci – Arg389Gly and Ser49Gly; the frequency of occurrence of variant and less functionally active alleles Gly389 and Gly49 in Europeans reaches 27% and 15%. The variant Gly389 allele has reduced functional activity and carriers have a weak response to the use of beta-blockers. In carriers of variant alleles Gly389 and Gly49 a reduced hypotensive effect on the use of beta-blockers was observed, and in studies of long-term efficacy, carriage of variant alleles was accompanied by an increase in the frequency and risk of unfavorable outcomes of hypertension. In pharmacogenetic studies, a reduced effect of the effect on myocardial remodeling in patients with CHF for beta-blockers in carriers of the variant Gly389 allele were confirmed. According to two meta-analyzes of trials on use of beta-blockers in patients with CHF, the frequency of increased left ventricle ejection fraction was significantly higher in carriers of the wild Arg389Arg gene type (risk ratio=1.83, p=0,001). In contrast, in atrial fibrillation, the frequency of rhythm control with beta-blockers was achieved better in the presence of the variant allele Gly389 with “loss of function”. Another polymorphic Gly49 allele plays a role in desensitization and down-regulation of beta1-receptor activity, although clinically this effect has been less obvious and contradictory. However, in studies, a more pronounced clinical effect of beta-blockers was observed in carriers of the wild genotype Ser49Ser, as well as in carriers of the haplotype Ser49Ser/Arg389Arg. Thus, genetic polymorphism ADRB1 may be another important predictor of the effectiveness of beta-blockers in clinical practice, which must be taken into account in the treatment of cardiovascular diseases.

Pharmacogenetics to guide cardiovascular drug therapy

Over the past decade, pharmacogenetic testing has emerged in clinical practice to guide selected cardiovascular therapies. The most common implementation in practice is CYP2C19 genotyping to predict clopidogrel response and assist in selecting antiplatelet therapy after percutaneous coronary intervention. Additional examples include genotyping to guide warfarin dosing and statin prescribing. Increasing evidence exists on outcomes with genotype-guided cardiovascular therapies from multiple randomized controlled trials and observational studies. Pharmacogenetic evidence is accumulating for additional cardiovascular medications. However, data for many of these medications are not yet sufficient to support the use of genotyping for drug prescribing. Ultimately, pharmacogenetics might provide a means to individualize drug regimens for complex diseases such as heart failure, in which the treatment armamentarium includes a growing list of medications shown to reduce morbidity and mortality. However, sophisticated analytical approaches are likely to be necessary to dissect the genetic underpinnings of responses to drug combinations. In this Review, we examine the evidence supporting pharmacogenetic testing in cardiovascular medicine, including that available from several clinical trials. In addition, we describe guidelines that support the use of cardiovascular pharmacogenetics, provide examples of clinical implementation of genotype-guided cardiovascular therapies and discuss opportunities for future growth of the field.

Adverse Cardiovascular Outcomes and Antihypertensive Treatment: A Genome-Wide Interaction Meta-Analysis in the International Consortium for Antihypertensive Pharmacogenomics Studies

We sought to identify genome-wide variants influencing antihypertensive drug response and adverse cardiovascular outcomes, utilizing data from four randomized controlled trials in the International Consortium for Antihypertensive Pharmacogenomics Studies (ICAPS). Genome-wide antihypertensive drug-single nucleotide polymorphism (SNP) interaction tests for four drug classes (β-blockers, n = 9,195; calcium channel blockers (CCBs), n = 10,511; thiazide/thiazide-like diuretics, n = 3,516; ACE-inhibitors/ARBs, n = 2,559) and cardiovascular outcomes (incident myocardial infarction, stroke, or death) were analyzed among patients with hypertension of European ancestry. Top SNPs from the meta-analyses were tested for replication of cardiovascular outcomes in an independent Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) study (n = 21,267), blood pressure (BP) response in independent ICAPS studies (n = 1,552), and ethnic validation in African Americans from the Genetics of Hypertension Associated Treatment study (GenHAT; n = 5,115). One signal reached genome-wide significance in the β-blocker-SNP interaction analysis (rs139945292, Interaction P = 1.56 × 10-8 ). rs139945292 was validated through BP response to β-blockers, with the T-allele associated with less BP reduction (systolic BP response P = 6 × 10-4 , Beta = 3.09, diastolic BP response P = 5 × 10-3 , Beta = 1.53). The T-allele was also associated with increased adverse cardiovascular risk within the β-blocker treated patients' subgroup (P = 2.35 × 10-4 , odds ratio = 1.57, 95% confidence interval = 1.23-1.99). The locus showed nominal replication in CHARGE, and consistent directional trends in β-blocker treated African Americans. rs139945292 is an expression quantitative trait locus for the 50 kb upstream gene NTM (neurotrimin). No SNPs attained genome-wide significance for any other drugs classes. Top SNPs were located near CALB1 (CCB), FLJ367777 (ACE-inhibitor), and CES5AP1 (thiazide). The NTM region is associated with increased risk for adverse cardiovascular outcomes and less BP reduction in β-blocker treated patients. Further investigation into this region is warranted.

Pharmacogenomic Effects of β-Blocker Use on Femoral Neck Bone Mineral Density

CONTEXT

Recent studies have shown that β-blocker (BB) users have a decreased risk of fracture and higher bone mineral density (BMD) compared to nonusers, likely due to the suppression of adrenergic signaling in osteoblasts, leading to increased BMD. There is also variability in the effect size of BB use on BMD in humans, which may be due to pharmacogenomic effects.

OBJECTIVE

To investigate potential single-nucleotide variations (SNVs) associated with the effect of BB use on femoral neck BMD, we performed a cross-sectional analysis using clinical data, dual-energy x-ray absorptiometry, and genetic data from the Framingham Heart Study's (FHS) Offspring Cohort. We then sought to validate our top 4 genetic findings using data from the Rotterdam Study, the BPROOF Study, the Malta Osteoporosis Fracture Study (MOFS), and the Hertfordshire Cohort Study.

METHODS

We used sex-stratified linear mixed models to determine SNVs that had a significant interaction effect with BB use on femoral neck (FN) BMD across 11 gene regions. We also evaluated the association of our top SNVs from the FHS with microRNA (miRNA) expression in blood and identified potential miRNA-mediated mechanisms by which these SNVs may affect FN BMD.

RESULTS

One variation (rs11124190 in HDAC4) was validated in females using data from the Rotterdam Study, while another (rs12414657 in ADRB1) was validated in females using data from the MOFS. We performed an exploratory meta-analysis of all 5 studies for these variations, which further validated our findings.

CONCLUSION

This analysis provides a starting point for investigating the pharmacogenomic effects of BB use on BMD measures.

Pharmacogenomics in Cardiovascular Diseases

Cardiovascular pharmacogenomics is the study and identification of genomic markers that are associated with variability in cardiovascular drug response, cardiovascular drug-related outcomes, or cardiovascular drug-related adverse events. This overview presents an introduction and historical background to cardiovascular pharmacogenomics, and a protocol for designing a cardiovascular pharmacogenomics study. Important considerations are also included for constructing a cardiovascular pharmacogenomics phenotype, designing the replication or validation strategy, common statistical approaches, and how to put the results in context with the cardiovascular drug or cardiovascular disease under investigation. © 2021 Wiley Periodicals LLC. Basic Protocol: Designing a cardiovascular pharmacogenomics study.

Pharmacogenetic factors affecting β-blocker metabolism and response

INTRODUCTION

β-blockers are among the most widely prescribed of all drugs, used for treatment of a large number of cardiovascular diseases. Herein we evaluate literature pertaining to pharmacogenetics of β-blocker therapy, provide insight into the robustness of the genetic associations, and determine the appropriateness for translating these genetic associations into clinical practice.

AREAS COVERED

A literature search was conducted using PubMed to collate evidence on associations between CYP2D6, ADRB1, ADRB2, and GRK5 genetic variation and drug-response outcomes in the presence of β-blocker exposure. Pharmacokinetic, pharmacodynamic, and clinical outcomes studies were included if genotype data and β-blocker exposure were documented.

EXPERT OPINION

Substantial data suggest that specific ADRB1 and GRK5 genotypes are associated with improved β-blocker efficacy and have potential for use to guide therapy decisions in the clinical setting. While the data do not justify ordering a CYP2D6 pharmacogenetic test, if CYP2D6 genotype is available in the electronic health record, there may be clinical utility for understanding dosing of β-blockers.

Pharmacogenomics of Hypertension Treatment

Hypertension is one of the strongest modifiable cardiovascular risk factors, affecting an increasing number of people worldwide. Apart from poor medication adherence, the low efficacy of some therapies could also be related to inter-individual genetic variability. Genetic studies of families revealed that heritability accounts for 30% to 50% of inter-individual variation in blood pressure (BP). Genetic factors not only affect blood pressure (BP) elevation but also contribute to inter-individual variability in response to antihypertensive treatment. This article reviews the recent pharmacogenomics literature concerning the key classes of antihypertensive drugs currently in use (i.e., diuretics, β-blockers, ACE inhibitors, ARB, and CCB). Due to the numerous studies on this topic and the sometimes-contradictory results within them, the presented data are limited to several selected SNPs that alter drug response. Genetic polymorphisms can influence drug responses through genes engaged in the pathogenesis of hypertension that are able to modify the effects of drugs, modifications in drug–gene mechanistic interactions, polymorphisms within drug-metabolizing enzymes, genes related to drug transporters, and genes participating in complex cascades and metabolic reactions. The results of numerous studies confirm that genotype-based antihypertension therapies are the most effective and may help to avoid the occurrence of major adverse events, as well as decrease the costs of treatment. However, the genetic heritability of drug response phenotypes seems to remain hidden in multigenic and multifactorial complex traits. Therefore, further studies are required to analyze all associations and formulate final genome-based treatment recommendations.

Analytical validity of a genotyping assay for use with personalized antihypertensive and chronic kidney disease therapy

Hypertension and chronic kidney disease are inextricably linked. Hypertension is a well-recognized contributor to chronic kidney disease progression and, in turn, renal disease potentiates hypertension. A generalized approach to drug selection and dosage has not proven effective in managing these conditions, in part, because patients with heterogeneous kidney disease and hypertension etiologies are frequently grouped according to functional or severity classifications. Genetic testing may serve as an important tool in the armamentarium of clinicians who embrace precision medicine. Increasing scientific evidence has supported the utilization of genomic information to select efficacious antihypertensive therapy and understand hereditary contributors to chronic kidney disease progression. Given the wide array of antihypertensive agents available and diversity of genetic renal disease predictors, a panel-based approach to genotyping may be an efficient and economic means of establishing an individualized blood pressure response profile for patients with various forms of chronic kidney disease and hypertension. In this manuscript, we discuss the validation process of a Clinical Laboratory Improvement Amendments-approved genetic test to relay information on 72 genetic variants associated with kidney disease progression and hypertension therapy. These genomic-based interventions, in addition to routine clinical data, may help inform physicians to provide personalized therapy.

Comorbidity of asthma and hypertension may be mediated by shared genetic dysregulation and drug side effects

Asthma and hypertension are complex diseases coinciding more frequently than expected by chance. Unraveling the mechanisms of comorbidity of asthma and hypertension is necessary for choosing the most appropriate treatment plan for patients with this comorbidity. Since both diseases have a strong genetic component in this article we aimed to find and study genes simultaneously associated with asthma and hypertension. We identified 330 shared genes and found that they form six modules on the interaction network. A strong overlap between genes associated with asthma and hypertension was found on the level of eQTL regulated genes and between targets of drugs relevant for asthma and hypertension. This suggests that the phenomenon of comorbidity of asthma and hypertension may be explained by altered genetic regulation or result from drug side effects. In this work we also demonstrate that not only drug indications but also contraindications provide an important source of molecular evidence helpful to uncover disease mechanisms. These findings give a clue to the possible mechanisms of comorbidity and highlight the direction for future research.

β2 -Adrenergic Receptor Gene Affects the Heart Rate Response of β-Blockers: Evidence From 3 Clinical Studies

β-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.

Economic evaluation of a pharmacogenomic multi-gene panel test to optimize anti-hypertension therapy: simulation study

AIMS

Hypertension is the strongest modifiable risk factor for cardiovascular disease, affecting 80 million individuals in the US and responsible for ∼360,000 deaths, at total annual costs of $93.5 billion. Antihypertension therapies guided by single genotypes are clinically more effective and may avert more adverse events than the standard of care of layering anti-hypertensive drug therapies, thus potentially decreasing costs. This study aimed to determine the economic benefits of the implementation of multi-gene panel guided therapies for hypertension from the payer perspective within a 3-year time horizon.

MATERIALS AND METHODS

A simulation analysis was conducted for a panel of 10 million insured patients categorized clinically as untreated, treated but uncontrolled, and treated and controlled over a 3-year treatment period. Inputs included research data; empirical data from a 11-gene panel with known functional, heart, blood vessel, and kidney genotypes; and therapy efficacy and safety estimates from literature. Cost estimates were categorized as related to genetic testing, evaluation and management, medication, or adverse events.

RESULTS

Multi-gene panel guided therapy yielding savings of $6,256,607,500 for evaluation and management, $908,160,000 for medications, and $37,467,508,716 for adverse events, after accounting for incremental genetic testing costs of $2,355,540,000. This represents total 3-year savings of $42,276,736,216, or a 47% reduction, and 3-year savings of $4,228 and annual savings of $1,409 per covered patient.

CONCLUSIONS

A precision medicine approach to genetically guided therapy for hypertension patients using a multi-gene panel reduced total 3-year costs by 47%, yielding savings exceeding $42.3 billion in an insured panel of 10 million patients. Importantly, 89% of these savings are generated by averting specific adverse events and, thus, optimizing choice of therapy in function of both safety and efficacy.

Pharmacogenomic studies of hypertension: paving the way for personalized antihypertensive treatment

Introduction

Increasing clinical evidence supports the implementation of genotyping for anti-hypertensive drug dosing and selection. Despite robust evidence gleaned from clinical trials, the translation of genotype guided therapy into clinical practice faces significant challenges. Challenges to implementation include the small effect size of individual variants and the polygenetic nature of antihypertensive drug response, a lack of expert consensus on dosing guidelines even without genetic information, and proper definition of major antihypertensive drug toxicities. Balancing clinical benefit with cost, while overcoming these challenges, remains crucial.

Areas covered

This review presents the most impactful clinical trials and cohorts which continue to inform and guide future investigation. Variants were selected from among those identified in the Pharmacogenomic Evaluation of Antihypertensive Responses (PEAR), the Genetic Epidemiology of Responses to Antihypertensives study (GERA), the Genetics of Drug Responsiveness in Essential Hypertension (GENRES) study, the SOPHIA study, the Milan Hypertension Pharmacogenomics of hydro-chlorothiazide (MIHYPHCTZ), the Campania Salute Network, the International Verapamil SR Trandolapril Study (INVEST), the Nordic Diltiazem (NORDIL) Study, GenHAT, and others.

Expert Commentary

The polygenic nature of antihypertensive drug response is a major barrier to clinical implementation. Further studies examining clinical effectiveness are required to support broad-based implementation of genotype-based prescribing in medical practice.

A rare genetic variant of BPIFB4 predisposes to high blood pressure via impairment of nitric oxide signaling

BPIFB4 is associated with exceptional longevity: four single-nucleotide polymorphisms distinguish the wild-type form from a longevity-associated variant conferring positive effects on blood pressure. The effect of a rare variant (RV; allele frequency, 4%) on blood pressure is unknown. Here, we show that overexpression of RV-BPIFB4 in ex-vivo mouse vessels impairs phosphorylation of endothelial nitric oxide synthase (eNOS), blunting acetylcholine-evoked vasorelaxation; in vivo, virally mediated overexpression of RV-BPIFB4 increases blood pressure, an action absent in eNOS-deficient mice. In humans, we found RV carriers to have increased diastolic blood pressure, a finding that was more marked in subjects on anti-hypertensive medication; moreover, recombinant RV-BPIFB4 protein impaired eNOS function in ex-vivo human vessels. Thus, RV-BPIFB4 acts directly on blood pressure homeostasis and may represent a novel biomarker of vascular dysfunction and hypertension.

Precision Cardiovascular Medicine: State of Genetic Testing

In the 15 years following the release of the first complete human genome sequences, our understanding of rare and common genetic variation as determinants of cardiovascular disease susceptibility, prognosis, and therapeutic response has grown exponentially. As such, the use of genomics to enhance the care of patients with cardiovascular diseases has garnered increased attention from clinicians, researchers, and regulatory agencies eager to realize the promise of precision genomic medicine. However, owing to a large burden of "complex" common diseases, emphasis on evidence-based practice, and a degree of unfamiliarity/discomfort with the language of genomic medicine, the development and implementation of genomics-guided approaches designed to further individualize the clinical management of a variety of cardiovascular disorders remains a challenge. In this review, we detail a practical approach to genetic testing initiation and interpretation as well as review the current state of cardiovascular genetic and pharmacogenomic testing in the context of relevant society and regulatory agency recommendations/guidelines.

Pharmacogenetic Associations of β1-Adrenergic Receptor Polymorphisms With Cardiovascular Outcomes in the SPS3 Trial (Secondary Prevention of Small Subcortical Strokes)

BACKGROUND AND PURPOSE

Functional polymorphisms (Ser49Gly and Arg389Gly) in ADRB1 have been associated with cardiovascular and β-blocker response outcomes. Herein we examined associations of these polymorphisms with major adverse cardiovascular events (MACE), with and without stratification by β-blocker treatment in patients with a history of stroke.

METHODS

Nine hundred and twenty-six participants of the SPS3 trial's (Secondary Prevention of Small Subcortical Strokes) genetic substudy with hypertension were included. MACE included stroke, myocardial infarction, and all-cause death. Kaplan-Meier and multivariable Cox regression analyses were used. Because the primary component of MACE was ischemic stroke, we tested the association of Ser49Gly with ischemic stroke among 41 475 individuals of European and African ancestry in the NINDS (National Institute of Neurological Disorders and Stroke) SiGN (Stroke Genetics Network).

RESULTS

MACE was higher in carriers of the Gly49 allele than in those with the Ser49Ser genotype (10.5% versus 5.4%, log-rank P=0.005). Gly49 carrier status was associated with MACE (hazard ratio, 1.62; 95% confidence interval, 1.00-2.68) and ischemic stroke (hazard ratio, 1.81; 95% confidence interval, 1.01-3.23) in SPS3 and with small artery ischemic stroke (odds ratio, 1.14; 95% confidence interval, 1.03-1.26) in SiGN. In SPS3, β-blocker-treated Gly49 carriers had increased MACE versus non-β-blocker-treated individuals and noncarriers (hazard ratio, 2.03; 95% confidence interval, 1.20-3.45). No associations were observed with the Arg389Gly polymorphism.

CONCLUSION

Among individuals with previous small artery ischemic stroke, the ADRB1 Gly49 polymorphism was associated with MACE, particularly small artery ischemic stroke, a risk that may be increased among β-blocker-treated individuals. Further research is needed to define β-blocker benefit among ischemic stroke patients by ADRB1 genotype.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00059306.

Association of β-Adrenergic Receptor Gene Polymorphisms With Acute Coronary Syndrome and Cardiovascular Risk Factors in an Arab Population

We evaluated the association between beta-adrenergic receptor genes (ADRB1 and ADRB2) polymorphism, cardiovascular risk, and acute coronary syndrome (ACS) in individuals from an Arab ethnicity. A total of 388 Qatari participants were assessed and genotyped for ADRB1 (rs1801252 & rs1801253) and ADRB2 (rs1042718 & rs1042713) polymorphisms using allele-specific PCR. Minor allele frequencies (MAF) in each single-nucleotide polymorphisms (SNPs) did not show statistically significant difference between cases and controls. A higher proportion of patients with ACS had homozygous minor alleles (GG) for rs1801253 (28.8% vs 17.1%; P = .019) compared with controls. Among cases with ACS, there was an association of minor allele frequency (G) for rs1801253 with severe coronary artery stenosis (0.485 vs 0.428; P = .04) than that of insignificant stenosis (<50% stenosis). There was a 3-fold increased risk of significant coronary stenosis in patients with diabetes mellitus (DM) and carrier of rs1801253 genotypes with dominant model ( P = .01) and recessive model ( P = .05). There is a possible synergic association between DM, carrier of ADRB1 (Arg389Gly) variants, and significant coronary artery stenosis among Arabs. Further prospective studies with larger sample sizes are warranted to support our findings.

Cardiovascular Pharmacogenomics--Implications for Patients With CKD

CKD is an independent risk factor for cardiovascular disease (CVD). Thus, patients with CKD often require treatment with cardiovascular drugs, such as antiplatelet, antihypertensive, anticoagulant, and lipid-lowering agents. There is significant interpatient variability in response to cardiovascular therapies, which contributes to risk for treatment failure or adverse drug effects. Pharmacogenomics offers the potential to optimize cardiovascular pharmacotherapy and improve outcomes in patients with CVD, although data in patients with concomitant CKD are limited. The drugs with the most pharmacogenomic evidence are warfarin, clopidogrel, and statins. There are also accumulating data for genetic contributions to β-blocker response. Guidelines are now available to assist with applying pharmacogenetic test results to optimize warfarin dosing, selection of antiplatelet therapy after percutaneous coronary intervention, and prediction of risk for statin-induced myopathy. Clinical data, such as age, body size, and kidney function have long been used to optimize drug prescribing. An increasing number of institutions are also implementing genetic testing to be considered in the context of important clinical factors to further personalize drug therapy for patients with CVD.

Hypertension pharmacogenomics: in search of personalized treatment approaches

Cardiovascular and renal diseases are associated with many risk factors, of which hypertension is one of the most prevalent. Worldwide, blood pressure control is only achieved in ∼50% of those treated for hypertension, despite the availability of a considerable number of antihypertensive drugs from different pharmacological classes. Although many reasons exist for poor blood pressure control, a likely contributor is the inability to predict to which antihypertensive drug an individual is most likely to respond. Hypertension pharmacogenomics and other 'omics' technologies have the potential to identify genetic signals that are predictive of response or adverse outcome to particular drugs, and guide selection of hypertension treatment for a given individual. Continued research in this field will enhance our understanding of how to maximally deploy the various antihypertensive drug classes to optimize blood pressure response at the individual level. This Review summarizes the available literature on the most convincing genetic signals associated with antihypertensive drug responses and adverse cardiovascular outcomes. Future research in this area will be facilitated by enhancing collaboration between research groups through consortia such as the International Consortium for Antihypertensives Pharmacogenomics Studies, with the goal of translating replicated findings into clinical implementation.

Pharmacogenomics of hypertension and heart disease

Heart disease is a leading cause of death in the United States, and hypertension is a predominant risk factor. Thus, effective blood pressure control is important to prevent adverse sequelae of hypertension, including heart failure, coronary artery disease, atrial fibrillation, and ischemic stroke. Over half of Americans have uncontrolled blood pressure, which may in part be explained by interpatient variability in drug response secondary to genetic polymorphism. As such, pharmacogenetic testing may be a supplementary tool to guide treatment. This review highlights the pharmacogenetics of antihypertensive response and response to drugs that treat adverse hypertension-related sequelae, particularly coronary artery disease and atrial fibrillation. While pharmacogenetic evidence may be more robust for the latter with respect to clinical implementation, there is increasing evidence of genetic variants that may help predict antihypertensive response. However, additional research and validation are needed before clinical implementation guidelines for antihypertensive therapy can become a reality.

Relationship between the single nucleotide polymorphisms of β₂-adrenergic receptor 5'-regulatory region and essential hypertension in Chinese Kazakh ethnic minority group

OBJECTIVE

To study the correlation of β2-AR gene 5'-regulatory region SNPs and essential hypertension (EH) in Chinese Kazakh ethnic minority group.

METHODS

The Sequenom MassArray(®) SNP detection technology was used to detect β2-AR gene 5'-regulatory region SNPs in 150 Xinjiang Kazakh EH patients and 150 controls. Biochemical analyzer was used to detect lipid and other related biochemical parameters. SHEsis and other software were used to analyze linkage disequilibrium and haplotype.

RESULTS

Six loci rs205304 (-1023G/A), rs17108803 (-893T/G), rs12654778 (-654G/A), rs11168070 (-468C/G), rs11959427 (-367C/T) and rs2895795 (-1429T/A) polymorphisms of β2-AR gene 5'-regulatory region were found in the Xinjiang Kazakh populations. While, there was no significant difference between EH group and NH in genotypes and allele frequency of rs2053044, rs12654778, rs2895795, rs17108803 and rs11959427 (P>0.05). However; significant differences were detected of rs11168070 genotypes and allele frequency in two groups (P<0.05). Analysis of the linkage disequilibrium and haplotype in Kazakh population, there is a strong linkage disequilibrium of rs11168070, rs2053044, rs2895795 gene polymorphism in the EH group, and rs11168070, rs12654778, rs17108803 gene polymorphism in controls. Frequency of haplotype GTCCAT, GACTGT and ATGCGT in EH group was higher (P<0.05), while frequency of ATCTGT, ATGTGT, GTCCGT, GTCTAT, GACCAT and GTCTGT in the EH group was significantly lower than the control (P<0.05).

CONCLUSIONS

β2-AR gene 5'-regulatory region of rs11168070, rs2053044, rs17108803, rs12654778, rs11959427 and rs2895795 genetic polymorphism exists in Kazakh. Among them, rs11168070 locus genotype and allele frequency distribution in the two groups are significant differences. In six polymorphic loci, there is a strong linkage disequilibrium, which haplotypes GTCCAT, GACTGT, ATGCGT are risk factors of EH, and the ATCTGT, ATGTGT, GTCCGT, GTCTAT, GACCAT, GTCTGT are protective factors.

Association of common polymorphisms in β1-adrenergic receptor with antihypertensive response to carvedilol

OBJECTIVES

Marked interpatient variability exists in the blood pressure response to carvedilol, a nonselective β-blocker. Here we evaluated the influence of 4 common polymorphisms in genes of the β-adrenergic receptor on the antihypertensive efficacy of carvedilol in patients in a double-blinded monotherapy study.

METHODS

Eighty-seven subjects with uncomplicated essential hypertensive (49% men; age = 52.2 ± 11.1 years) from Jilin province of China were enrolled in the study, and 5 of them discontinued the treatment due to adverse effects. Both systolic and diastolic blood pressures (DBPs) were measured before and after 7 days of treatment with carvedilol (10 mg/d). Genotypes of the β1-adrenergic receptor (ADRB1 Ser49Gly and Arg389Gly) and β2-adrenergic receptor (ADRB2 Gly16Arg and Glu27Gln) were determined by polymerase chain reaction with restriction fragment length polymorphism.

RESULTS

Patients homozygous for ADRB1 Arg389 had an approximately 4-fold greater reduction in DBPs than those homozygous for ADRB1 Gly389 (10.61 vs. 2.62 mm Hg, P = 0.013). The ADRB1 haplotype was also a significant predictor of response, as patients with the Gly49Arg389/Ser49Arg389 haplotype pair had a 5.7-fold greater reduction in DBPs than those homozygous for the Ser49Gly389 haplotype (16.11 vs. 2.83 mm Hg, P = 0.0055). An association was not found between ADRB2 polymorphism and carvedilol responsiveness in antihypertensive therapy.

CONCLUSIONS

This study provides the first evidence to support that ADRB1 polymorphisms play an important role in the DBPs response to carvedilol treatment in patients with essential hypertension.

Genetics of cardiovascular disease: Importance of sex and ethnicity

Sex differences in incidence and prevalence of and morbidity and mortality from cardiovascular disease are well documented. However, many studies examining the genetic basis for cardiovascular disease fail to consider sex as a variable in the study design, in part, because there is an inherent difficulty in studying the contribution of the sex chromosomes in women due to X chromosome inactivation. This paper will provide general background on the X and Y chromosomes (including gene content, the pseudoautosomal regions, and X chromosome inactivation), discuss how sex chromosomes have been ignored in Genome-wide Association Studies (GWAS) of cardiovascular diseases, and discuss genetics influencing development of cardiovascular risk factors and atherosclerosis with particular attention to carotid intima-medial thickness, and coronary arterial calcification based on sex-specific studies. In addition, a brief discussion of how ethnicity and hormonal status act as confounding variables in sex-based analysis will be considered along with methods for statistical analysis to account for sex in cardiovascular disease.

An update on the pharmacogenetics of treating hypertension

Hypertension is a leading cause of cardiovascular mortality, but only one third of patients achieve blood pressure goals despite antihypertensive therapy. Genetic polymorphisms may partially account for the interindividual variability and abnormal response to antihypertensive drugs. Candidate gene and genome-wide approaches have identified common genetic variants associated with response to antihypertensive drugs. However, there is no currently available pharmacogenetic test to guide hypertension treatment in clinical practice. In this review, we aimed to summarize the recent findings on pharmacogenetics of the most commonly used antihypertensive drugs in clinical practice, including diuretics, angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers, beta-blockers and calcium channel blockers. Notably, only a small percentage of the genetic variability on response to antihypertensive drugs has been explained, and the vast majority of the genetic variants associated with antihypertensives efficacy and toxicity remains to be identified. Despite some genetic variants with evidence of association with the variable response related to these most commonly used antihypertensive drug classes, further replication is needed to confirm these associations in different populations. Further studies on epigenetics and regulatory pathways involved in the responsiveness to antihypertensive drugs might provide a deeper understanding of the physiology of hypertension, which may favor the identification of new targets for hypertension treatment and genetic predictors of antihypertensive response.

Genetic variation in the β1-adrenergic receptor is associated with the risk of atrial fibrillation after cardiac surgery

BACKGROUND

Postoperative atrial fibrillation (PoAF) after cardiac surgery is common and associated with increased morbidity and mortality. Increased sympathetic activation after surgery contributes to PoAF, and β-blockers are the first-line recommendation for its prevention. We examined the hypothesis that common functional genetic variants in the β1-adrenoreceptor, the mediator of cardiac sympathetic activation and drug target of β-blockers, are associated with the risk for PoAF and with the protective effect of β-blockers.

METHODS

In a prospective cohort study, we studied 947 adult European Americans who underwent cardiac surgery at Vanderbilt University between 1999 and 2005. We genotyped 2 variants in the β1-adrenoreceptor, rs1801253 (Arg389Gly) and rs1801252 (Ser49Gly), and used logistic regression to examine the association between genotypes and PoAF occurring within 14 days after surgery, before and after adjustment for demographic and clinical covariates.

RESULTS

Postoperative atrial fibrillation occurred in 239 patients (25.2%) and was associated with rs1801253 genotype (adjusted P = .008), with Gly389Gly having an odds ratio of 2.63 (95% CI 1.42-4.89) for PoAF compared to the common Arg389Arg (P = .002). In a predefined subgroup analysis, this association appeared to be stronger among patients without β-blocker prophylaxis (adjusted odds ratio 7.00, 95% CI 1.82-26.96, P = .005) compared to patients with β-blocker prophylaxis, among whom the association between rs1801253 genotype and PoAF was not statistically significant (adjusted P = .11).

CONCLUSION

The Gly389 variant in the β1-adrenoreceptor is associated with PoAF, and this association appears to be modulated by β-blocker therapy. Future studies of the association of other adrenergic pathway genes with PoAF will be of interest.