We sought to determine whether polymorphisms in the large-conductance calcium and voltage-dependent potassium (BK) channel β1 subunit gene, KCNMB1, are associated with blood pressure response to verapamil SR or adverse outcomes in the GENEtic substudy of the INternational VErapamil SR/trandolapril STudy (INVEST-GENES).
KCNMB1 is involved in calcium sensitivity and hypertension. The association between variability in KCNMB1 and calcium antagonist response, however, has not been assessed.
Genetic samples were collected from 5979 patients in INVEST. Blood pressure response to verapamil SR and time to achieve blood pressure control was assessed in relation to Glu65Lys and Val110Leu genotypes. The primary outcome (all cause mortality, nonfatal myocardial infarction or nonfatal stroke) was compared between genotype groups, and interaction with verapamil SR therapy was assessed.
Systolic blood pressure response to verapamil SR did not differ by KCNMB1 genotype. Lys65 variant carriers, however, achieved blood pressure control earlier than Glu65Glu individuals [1.47 (interquartile ratio 2.77) versus 2.83 (interquartile ratio 4.17) months, P = 0.01] and were less likely to require multiple drugs at the time of blood pressure control (adjusted odds ratio 0.43, 95% confidence interval 0.19–0.95). Leu110 variant carriers had a reduced risk of primary outcome (hazard ratio 0.68, 95% confidence interval 0.47–0.998). Subgroup analysis revealed this finding to be more pronounced in verapamil SR-assigned patients (hazard ratio 0.587, 95% confidence interval 0.33–1.04) compared with atenolol-assigned patients (hazard ratio 0.946, 95% confidence interval 0.56–1.59). No difference was seen in the occurrence of the primary outcome compared by codon 65 genotype.
Our findings suggest that KCNMB1 genotype influences responsiveness to verapamil SR and risk of adverse cardiovascular outcomes.
KCNMB1; polymorphism; verapamil SR
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
Liver X receptor-α (LXRA) is a nuclear receptor that regulates genes important in cholesterol homeostasis and inflammation. Several single nucleotide polymorphisms (SNPs) in the LXRA gene have been previously associated with metabolic phenotypes (dyslipidemia and elevated BMI). Metabolic dysregulation is a major contributor to coronary disease; therefore, we assessed LXRA in INVEST-GENES, a genetic-substudy of a large clinical trial in patients with hypertension and coronary artery disease.
Seven tag SNPs in the LXRA gene region (NR1H3) were selected for study: rs11039149, rs12221497, rs2279238, rs7120118, rs326213, rs11039159 and rs10501321. 1059 subjects were genotyped from the INVEST-GENES case-control set (Verapamil-SR or Atenolol based treatment strategies), comprised of 297 cases frequency matched approximately 2.5:1 with event-free controls by sex and race. The primary outcome was defined as first occurrence of all-cause death, nonfatal MI, or nonfatal stroke. Adjusted odds ratios (OR) were calculated using logistic regression.
Three of the seven SNPs were associated with significant effects on the primary outcome in Non-Blacks. The variant G allele of rs11039149 and the variant A allele of rs12221497 were associated with reduced risk of experiencing the primary outcome (OR: 0.62, CI: 0.45-0.85, P=0.003 and OR: 0.60, CI: 0.39-0.91, P=0.016 respectively). The rs2279238 genotype was associated with a significant increase in risk for the primary outcome (OR: 1.42, CI: 1.03-1.95, P=0.03). Furthermore, there was a significant genotype-treatment strategy interaction for carriers of the variant T allele of rs2279238 (OR for Verapamil SR strategy compared to Atenolol: 2.86, CI: 1.50-5.46, P=0.0015). Diplotype analyses revealed that the SNPs are rarely co-inherited and support the directionally opposite effects of the SNPs on the primary outcome.
LXRA genotypes were associated with variable risk for cardiovascular outcomes and pharmacogenetic effect in INVEST-GENES. These novel findings suggest LXRA is a genetic/pharmacogenetic target that should be further explored.
LXRA; Nuclear Receptor; Pharmacogenetics; Polymorphisms; Cardiovascular Disease; Hypertension; Atenolol; Verapamil
The INternational VErapamil SR-Trandolapril STudy (INVEST), a randomized trial of 22,576 predominantly elderly patients with an average 2.7-year follow-up, compared a calcium antagonist led strategy (verapamil SR plus trandolapril) with a β blocker led strategy (atenolol plus hydrochlorothiazide) for hypertension treatment and prevention of cardiovascular outcomes in coronary artery disease. patients.
Patients received individualized dose and drug titration following a flexible, multi-drug, guideline-based treatment algorithm, with the objective of achieving optimal blood pressure (BP) control individualized for comorbidities (e.g., diabetes). The primary outcome (PO) was first occurrence of death (all-cause), nonfatal myocardial infarction or nonfatal stroke.
The strategies resulted in significant and very similar BP reduction with approximately 70% of patients in both strategies achieving BP control (< 140/90 mm Hg). Increasing number of office visits with BP in control was associated with reduced risk of the PO. Overall, there was no difference in the PO comparing the strategies, however new onset diabetes occurred more frequently in those assigned the atenolol strategy. This report summarizes findings from INVEST and puts them in perspective with our current state of knowledge derived from other large hypertension treatment trials. INVEST findings support that 1) BP reduction is important for prevention of adverse cardiovascular morbidity and mortality; and 2) selection of antihypertensive agents should be based on patient comorbidities and other risk factors (e.g. risk for diabetes) and not necessarily that any one drug be given to all.
Coronary artery disease; hypertension; atenolol; verapamil SR; trandolapril; hydrochlorothiazide; INVEST; new onset diabetes
Hypertensive diabetes individuals are at higher risk for cardiovascular events and progression to end stage renal disease. Several well conducted clinical trials indicate that aggressive treatment of hypertension in individual with diabetes reduces these complications. Combinations of two or more antihypertensive drugs are frequently required to reach the target blood pressure and to improve the cardiovascular and renal outcomes in these patients. There are physiological and clinical rationales for renin-angiotensin system blockade in hypertensive diabetics. Trandolapril/verapamil sustained released (SR) is a fixed-dose combination of trandolapril and a sustained release formulation of verapamil and indicated in treatment of hypertension in patients who require more than one drug to reach target blood pressure. The antihypertensive efficacy of trandolapril/verapamil SR has been evaluated extensively in large trials. In the INVEST trial, a verapamil SR-based treatment strategy that included trandolapril in most patients was effective in reducing the primary outcome in hypertensive patients with coronary artery disease. The new onset of diabetes was also significantly lower in the verapamil SR/trandolapril treatment group in comparison with those on the atenolol/hydroclorothiazide treatment group. The BErgamo NEphrologic DIabetes Complications Trial (BENEDICT) documented that in hypertensive diabetes and normoalbuminuria, trandolapril plus verapamil or trandolapril alone delayed the onset of microalbuminuria independent of their blood pressure-reducing effect. Thus, trandolapril/verapamil is an effective option for treatment of hypertensive diabetes patients requiring more than one agent to achieve target blood pressure.
diabetes mellitus; hypertension; trandolapril; verapamil SR
The CACNA1C gene (alpha 1C subunit of the L-type voltage-gated calcium channel) has been identified as a risk gene for both bipolar disorder and schizophrenia but the mechanism of association has not been explored.
To identify the neural system mechanism that explains the genetic association between the CACNA1C gene and psychiatric illness, using neuroimaging and human brain expression.
We used BOLD fMRI to measure brain activation in circuitries related to bipolar disorder and schizophrenia by comparing CACNA1C genotype groups in healthy subjects. We tested the effect of genotype on mRNA levels of CACNA1C in post-mortem human brain. A case-control analysis was used to determine the association of CACNA1C genotype and schizophrenia.
National Institutes of Health Clinical Center
Healthy Caucasian men and women participated in the fMRI study. Post-mortem samples from normal human brains were used for the brain expression study. Patients with schizophrenia and healthy subjects were used in the case-control analysis.
Main Outcome Measures
BOLD fMRI, mRNA levels in post-mortem brain samples, and genetic association with schizophrenia
The risk associated single nucleotide polymorphism (SNP rs1006737) in CACNA1C predicted increased hippocampal activity during emotional processing (puncorr=0.001, pFDR=0.052, Z=3.20) and increased prefrontal activity during executive cognition (puncorr=2.8e-05, pFDR=0.011, Z=4.03). The risk SNP also predicted increased expression of CACNA1C mRNA in human brain (p=0.0017). CACNA1C was associated with schizophrenia in our case-control sample (OR 1.77, p=0.026).
The risk associated SNP in CACNA1C maps to circuitries implicated in genetic risk for both bipolar disorder and schizophrenia. Its effects in human brain expression implicate a molecular and neural systems mechanism for the clinical genetic association.
Calcium channel blocker poisoning is a common and sometimes life-threatening ingestion.
To evaluate the reported effects of treatments for calcium channel blocker poisoning. The primary outcomes of interest were mortality and hemodynamic parameters. The secondary outcomes included length of stay in hospital, length of stay in intensive care unit, duration of vasopressor use, functional outcomes, and serum calcium channel blocker concentrations.
Medline/Ovid, PubMed, EMBASE, Cochrane Library, TOXLINE, International pharmaceutical abstracts, Google Scholar, and the gray literature up to December 31, 2013 were searched without time restriction to identify all types of studies that examined effects of various treatments for calcium channel blocker poisoning for the outcomes of interest. The search strategy included the following Keywords: [calcium channel blockers OR calcium channel antagonist OR calcium channel blocking agent OR (amlodipine or bencyclane or bepridil or cinnarizine or felodipine or fendiline or flunarizine or gallopamil or isradipine or lidoflazine or mibefradil or nicardipine or nifedipine or nimodipine or nisoldipine or nitrendipine or prenylamine or verapamil or diltiazem)] AND [overdose OR medication errors OR poisoning OR intoxication OR toxicity OR adverse effect]. Two reviewers independently selected studies and a group of reviewers abstracted all relevant data using a pilot-tested form. A second group analyzed the risk of bias and overall quality using the STROBE (STrengthening the Reporting of OBservational studies in Epidemiology) checklist and the Thomas tool for observational studies, the Institute of Health Economics tool for Quality of Case Series, the ARRIVE (Animal Research: Reporting In Vivo Experiments) guidelines, and the modified NRCNA (National Research Council for the National Academies) list for animal studies. Qualitative synthesis was used to summarize the evidence. Of 15,577 citations identified in the initial search, 216 were selected for analysis, including 117 case reports. The kappa on the quality analysis tools was greater than 0.80 for all study types.
The only observational study in humans examined high-dose insulin and extracorporeal life support. The risk of bias across studies was high for all interventions and moderate to high for extracorporeal life support. High-dose insulin. High-dose insulin (bolus of 1 unit/kg followed by an infusion of 0.5–2.0 units/kg/h) was associated with improved hemodynamic parameters and lower mortality, at the risks of hypoglycemia and hypokalemia (low quality of evidence). Extracorporeal life support. Extracorporeal life support was associated with improved survival in patients with severe shock or cardiac arrest at the cost of limb ischemia, thrombosis, and bleeding (low quality of evidence). Calcium, dopamine, and norepinephrine. These agents improved hemodynamic parameters and survival without documented severe side effects (very low quality of evidence). 4-Aminopyridine. Use of 4-aminopyridine was associated with improved hemodynamic parameters and survival in animal studies, at the risk of seizures. Lipid emulsion therapy. Lipid emulsion was associated with improved hemodynamic parameters and survival in animal models of intravenous verapamil poisoning, but not in models of oral verapamil poisoning. Other studies. Studies on decontamination, atropine, glucagon, pacemakers, levosimendan, and plasma exchange reported variable results, and the methodologies used limit their interpretation. No trial was documented in humans poisoned with calcium channel blockers for Bay K8644, CGP 28932, digoxin, cyclodextrin, liposomes, bicarbonate, carnitine, fructose 1,6-diphosphate, PK 11195, or triiodothyronine. Case reports were only found for charcoal hemoperfusion, dialysis, intra-aortic balloon pump, Impella device and methylene blue.
The treatment for calcium channel blocker poisoning is supported by low-quality evidence drawn from a heterogeneous and heavily biased literature. High-dose insulin and extracorporeal life support were the interventions supported by the strongest evidence, although the evidence is of low quality.
Antidotes; Calcium channel blockers; Cardiotoxins; Drug overdose; Poisoning; Toxicity; Treatment
G protein-coupled receptor kinases (GRKs) are important regulatory proteins for many G protein-coupled receptors, but little is known about GRK4 pharmacogenetics. We hypothesized three nonsynonymous GRK4 SNPs, R65L (rs2960306), A142V (rs1024323) and A486V (rs1801058) would be associated with blood pressure response to atenolol, but not hydrochlorothiazide, and would be associated with long term cardiovascular outcomes (all cause, death, nonfatal myocardial infarction, nonfatal stroke) in participants treated with an atenolol-based versus verapamil-SR-based antihypertensive strategy. GRK4 SNPs were genotyped in 768 hypertensive participants from the Pharmacogenomic Evaluation of Antihypertensive Responses (PEAR) trial. In Caucasians and African Americans, increasing copies of the variant 65L-142V haplotype were associated with significantly reduced atenolol-induced diastolic blood pressure lowering (−9.1 ± 6.8 vs −6.8 ± 7.1 vs −5.3 ± 6.4 mmHg in participants with 0, 1 and 2 copies of 65L-142V respectively; p=0.0088). 1460 participants with hypertension and coronary artery disease from the INternational VErapamil SR / Trandolapril STudy (INVEST) were genotyped and variant alleles of all three GRK4 SNPs were associated with increased risk for adverse cardiovascular outcomes in an additive fashion, with 486V homozygotes reaching statistical significance (Odds ratio 2.29 [1.48–3.55], p=0.0002). These effects on adverse cardiovascular outcomes were independent of antihypertensive treatment. These results suggest the presence of GRK4 variant alleles may be important determinants of blood pressure response to atenolol and risk for adverse cardiovascular events. The associations with GRK4 variant alleles were stronger in patients who were also ADRB1 389R-homozygotes, suggesting a potential interaction between these two genes.
hypertension; GRK4; atenolol; beta-blocker; outcomes; ADRB1; pharmacogenetics
The G-protein coupled receptor kinases GRK2 and GRK5 are important regulators of beta-adrenergic signaling. This study characterized single nucleotide polymorphisms in the GRK2 gene (ADRBK1)and determined if these and a GRK5 Gln41Leu polymorphism affect the blood pressure (BP)response to atenolol or hydrochlorothiazide or adverse cardiovascular outcomes in hypertensives.
ADRBK1 regions were sequenced for 48 individuals. Putative functional SNPs were tested for mRNA expression differences in 96 lymphoblastoid cell line samples and 12 leukocyte samples from hypertensives. BP response to atenolol and hydrochlorothiazide by ADRBK1 SNPs and GRK5 Gln41Leuwas tested in 418patients from the Pharmacogenomic Evaluation of Antihypertensive Responses (PEAR) using linear regression. The influence of ADRBK1 SNPs and GRK5 Gln41Leuon death, myocardial infarction or stroke in treated hypertensive patients was evaluated in a case-control cohort (1:3) of the International Verapamil SR/Trandolapril Study GENEtic Substudy (INVEST GENES) using logistic regression models.
A novel ADRBK1 promoter SNP was not associated with differential GRK2 expression. GRK5 Leu41 decreased the risk for adverse cardiovascular outcomes independent of treatment strategy(adjusted odds ratio 0.535, 95% confidence interval 0.313 – 0.951, P = 0.0222)but was not associated with BP response to antihypertensive medication. An ADRBK1 SNP (rs1894111G>A) showed a signal for association with systolic and diastolic BP(SBP, DBP) response to hydrochlorothiazide in whites(DBP: −11.29±3.74 mmHg (G/A) vs. −4.26±4.79 mmHg (G/G), P = 0.0034 and SBP: −18.37±14.90 mmHg (G/A), −8.11±7.55 mmHg (G/G), P = 0.0191).
The GRK5 Leu41 allele protects from adverse cardiovascular outcomes in treated hypertensives.
GRK5; GRK2; ADRBK1; polymorphism; hypertension; beta-blocker; atenolol; diuretic; hydrochlorothiazide
Background: Fixed-dose combination antihypertensive therapy has been recommended for patients with essential hypertension who are unresponsive to monotherapy or as a first-line treatment.
Objective: We investigated the effects of a fixed-dose combination of the phenylalkylamine-type calcium channel blocker verapamil slow release (SR)plus the angiotensin-converting enzyme inhibitor trandolapril on blood pressure (BP), serum lipid profile, urinary albumin excretion (UAE), left ventricular mass (LVM), and LVM index (LVMI), as well as the adverse events associated with this treatment.
Methods: Patients aged 30 to 65 years with mild to moderate essential hypertension were included in the study. All of the patients received capsules containing combination treatment with verapamil SR 180 mg plus trandolapril 2 mg orally, daily for 12 weeks. Mean arterial pressure (MAP), systolic BP (SBP), diastolic BP (DBP), and heart rate (HR) were measured at baseline and at 4, 8, and 12 weeks of treatment. Serum lipid profile, UAE, LVM, LVMI, and body mass index (BMI) were determined at baseline and at the end of the study period. All patients underwent electrocardiography and echocardiography at baseline and week 12. The primary end point of the study was to achieve an SBP/DBP ≤140/≤90 mm Hg (ie, normotensive) during week 12. All adverse events were assessed as mild, moderate, or severe at each visit. According to the response rate at week 12, patients were divided into 2 groups: those who became normotensive (responders) or those who remained hypertensive (SBP/DBP >140/>90 mm Hg; nonresponders).
Results: Forty-one patients (29 women, 12 men; mean [SD] age, 47.7 [7.8] years; mean [SD] BMI, 29.4 [3.5] kg/m2) were enrolled. The median durationof hypertension prior to enrollment was 5 months. Mean MAP, SBP, DBP, UAE, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), LDL-C/highdensity lipoprotein cholesterol (HDL-C) ratio, LVM, LVMI, and BMI decreased significantly after 12 weeks of combination treatment; HR and triglyceride level did not change significantly. Treatment-related adverse events occurred in 31.7% of patients, and none were severe or caused any patient to withdraw from the study. The most common adverse events were cough, constipation, headache, and dryness in the throat. Microalbuminuria, which may be a marker of endothelial dysfunction, was found in 7 (17.1%) patients at baseline and regressed significantly after 12 weeks.
Conclusions: In this study population, the fixed-dose combination of verapamil–trandolapril was an effective and well-tolerated antihypertensive therapy. This combination significantly reduced MAP, BP, TC, LDL-C, LDL-C/HDL-C ratio, UAE, LVM, and LVMI. Also, microalbuminuria decreased after this treatment. Verapamil–trandolapril may be useful in preventing microalbuminuria and left ventricular hypertrophy in patients with essential hypertension.
essential hypertension; combination therapy; trandolapril; verapamil
Factors such as age and race/ethnicity might influence blood pressure (BP) response to drugs. Therapeutic response to the angiotensin-converting enzyme inhibitor trandolapril used as add-on therapy to stable calcium channel blocker therapy with verapamil sustained release 240 mg was addressed in a racially/ethnically diverse group of 1,832 hypertensive patients with coronary artery disease. Furthermore, the association with a polymorphism (1166A→C) in the angiotensin II type 1 receptor gene (AGTR1) was tested. BP response was compared between groups using analysis of covariance after adjustment for covariates associated with BP response. Genotyping was performed using polymerase chain reaction and pyrosequencing. Trandolapril decreased mean unadjusted systolic and diastolic BPs by −9.1 ± 17.3 (SD) and −4.1 ± 10.1 mm Hg, respectively. The percentage of patients with BP under control (<140/90 mm Hg) increased from 6.7% to 41.3% (p <0.0001). Adjusted BP response was significantly associated with age and baseline systolic and diastolic BP (p <0.0001). Whereas the decrease in systolic BP was more pronounced in younger patients, the opposite was observed for diastolic BP decrease. Diastolic BP response was also significantly associated with race. Specifically, the adjusted diastolic BP decrease was significantly smaller in Hispanics and blacks than whites (p = 0.0032 and p = 0.0069, respectively). However, Hispanics achieved a decrease in systolic BP and an increase in BP control similar to the other ethnic groups. There was no genetic association between AGTR1 1166A→C genotype and BP response. In conclusion, trandolapril add-on therapy was effective in increasing BP control, with age and baseline BP associated with both systolic and diastolic BP response. Race was associated with diastolic BP response, although the difference is likely not to be clinically significant and AGTR1 genotype was not associated with BP response.
Verapamil has been shown to be neuroprotective in several acute neurotoxicity models due to blockade of calcium entry into neurons. However, the potential use of verapamil to treat chronic neurodegenerative diseases has not been reported. Using rat primary mesencephalic neuron/glia cultures, we report that verapamil significantly inhibited LPS-induced dopaminergic neurotoxicity in both pre- and post-treatment experiments. Reconstituted culture studies revealed that the presence of microglia was essential in verapamil-elicited neuroprotection. Mechanistic studies showed that decreased production of inflammatory mediators from LPS-stimulated microglia underlay neuroprotective property of verapamil. Further studies demonstrated that microglial NADPH oxidase (PHOX), the key superoxide-producing enzyme, but not calcium channel in neurons, is the site of action for the neuroprotective effect of verapamil. This conclusion was supported by the following two observations: 1) Verapamil failed to show protective effect on LPS-induced dopaminergic neurotoxicity in PHOX-deficient (deficient in the catalytic subunit of gp91phox) neuron/glia cultures; 2) Ligand binding studies showed that the binding of [3H]Verapamil onto gp91phox transfected COS-7 cell membranes was higher than the non-transfected control. The calcium channel-independent neuroprotective property of verapamil was further supported by the finding that R(+)-verapamil, a less active form in blocking calcium channel, showed the same potency in neuroprotection, inhibition of pro-inflammatory factors production and binding capacity to gp91phox membranes as R(-)-verapamil, the active isomer of calcium channel blocker. In conclusion, our results demonstrate a new indication of verapamil-mediated neuroprotection through a calcium channel-independent pathway and provide a valuable avenue for the development of therapy for inflammation-related neurodegenerative diseases.
calcium channel blocker; oxidative stress; neuroinflammation
Our understanding of the growing population of very old patients (aged ≥80 years) with coronary artery disease and hypertension is limited, particularly the relationship between blood pressure and adverse outcomes.
This was a secondary analysis of the INternational VErapamil SR-Trandolapril STudy (INVEST), which involved 22,576 clinically stable hypertensive coronary artery disease patients aged ≥50 years. The patients were grouped by age in 10-year increments (aged ≥80, n = 2180; 70–<80, n = 6126; 60–<70, n = 7602; <60, n =6668). Patients were randomized to either verapamil SR- or atenolol-based treatment strategies, and primary outcome was first occurrence of all-cause death, nonfatal myocardial infarction, or nonfatal stroke.
At baseline, increasing age was associated with higher systolic blood pressure, lower diastolic blood pressure, and wider pulse pressure (P <.001). Treatment decreased systolic, diastolic, and pulse pressure for each age group. However, the very old retained the widest pulse pressure and the highest proportion (23.6%) with primary outcome. The adjusted hazard ratio for primary outcomes showed a J-shaped relationship among each age group with on-treatment systolic and diastolic pressures. The systolic pressure at the hazard ratio nadir increased with increasing age, highest for the very old (140 mm Hg). However, diastolic pressure at the hazard ratio nadir was only somewhat lower for the very old (70 mm Hg). Results were independent of treatment strategy.
Optimal management of hypertension in very old coronary artery disease patients may involve targeting specific systolic and diastolic blood pressures that are higher and somewhat lower, respectively, compared with other age groups.
Age; Blood pressure control; Coronary artery disease; Elderly; Epidemiology; Hypertension
Polymorphisms (SNPs) within the regulatory β2 subunit of the voltage-gated calcium channel (CACNB2) may contribute to variable treatment response to antihypertensive drugs and adverse cardiovascular outcomes.
Methods and Results
SNPs in CACNB2 from 60 ethnically diverse individuals were identified and characterized. Three common SNPs (rs2357928, rs7069292 and rs61839258) and a GWAS identified intronic SNP (rs11014166) were genotyped for a clinical association study in 5,598 hypertensive patients with coronary artery disease randomized to a beta-blocker (BB) or a calcium channel blocker (CCB) treatment strategy in INVEST-GENES. Reporter gene assays were conducted on the promoter SNP showing association with clinical outcomes. Twenty-one novel SNPs were identified. A promoter A>G SNP (rs2357928) was found to have significant interaction with treatment strategy for adverse cardiovascular outcomes (p for interaction = 0.002). In Caucasians, rs2357928 GG patients randomized to CCB were more likely to experience adverse outcome than those randomized to BB treatment strategy, with adjusted hazard ratio (CCB vs. BB) of 2.35 (1.19-4.66), p = 0.014. There was no evidence for such treatment difference in AG (1.16, 0.75-1.79, p = 0.69) and AA individuals (0.63, 0.36-1.11, p = 0.11). This finding was consistent in Hispanics and African Americans. CACNB2 rs11014166 showed similar pharmacogenetic effect in Hispanics, but not in Caucasians or African Americans. Reporter assay analysis of rs2357928 showed a significant increase in promoter activity for the G allele compared to the A allele.
These data suggest genetic variation within CACNB2 may influence treatment related outcomes in high risk hypertensive patients.
Clinical Trial Registration Information
Clinical trial identifier: NCT00133692, URL: http://clinicaltrials.gov/ct/gui/show/NCT00133692).
Genetic variations; CACNB2; hypertension; cardiovascular outcomes; INVEST-GENES
The voltage-dependent L-type calcium channel α-subunit 1c (Cav1.2, CACNA1C) undergoes extensive mRNA splicing, leading to numerous isoforms with different functions. L-type calcium channel blockers are used in the treatment of hypertension and arrhythmias, but response varies between individuals. We have studied the interindividual variability in mRNA expression and splicing of CACNA1C, in 65 heart tissue samples, taken from heart transplant recipients.
Splice variants were measured quantitatively by polymerase chain reaction in 12 splicing loci of CACNA1C mRNA. To search for functional cis-acting polymorphisms, we determined allelic expression ratios for total CACNA1C mRNA and several splice variants using marker single nucleotide polymorphisms in exon 4 and exon 30.
Total CACNA1C mRNA levels varied ∼50-fold. Substantial splicing occurred in six loci generating two or more splice variants, some with known functional differences. Splice patterns varied broadly between individuals. Two heart tissues expressed predominantly the dihydropyridine-sensitive smooth muscle isoform of CACNA1C (containing exon 8), rather than the cardiac isoform (containing exon 8a). Lack of significant allelic expression imbalance, observed with total mRNA and several splice variants, argued against CACNA1C polymorphisms as a cause of variability. Taken together, highly variable splicing can cause profound phenotypic variations of CACNA1C function, potentially associated with disease susceptibility and response to L-type calcium channel blockers.
cis-acting polymorphism; L-type calcium channel α-subunit 1c; mRNA splicing
Numerous studies have demonstrated that β1- and β2-adrenergic receptor gene (ADRB1 and ADRB2) variants influence cardiovascular risk and β-blocker responses in hypertension and heart failure. We evaluated the relationship between ADRB1 and ADRB2 haplotypes, cardiovascular risk (death, nonfatal myocardial infarction (MI ), and nonfatal stroke), and atenolol-based vs. verapamil sustained-release (SR )-based antihypertensive therapy in 5,895 coronary artery disease (CAD) patients. After an average of 2.8 years, death rates were higher in patients carrying the ADRB1 Ser49-Arg389 haplotype (hazard ratio (HR ) 3.66, 95% confidence interval (95% CI) 1.68–7.99). This mortality risk was significant in patients randomly assigned to verapamil SR (HR 8.58, 95% CI 2.06–35.8) but not atenolol (HR 2.31, 95% CI 0.82–6.55), suggesting a protective role for the β-blocker. ADRB2 haplotype associations were divergent within the treatment groups but did not remain significant after adjustment for multiple comparisons. ADRB1 haplotype variation is associated with mortality risk, and β-blockers may be preferred in subgroups of patients defined by ADRB1 or ADRB2 polymorphisms.
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
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
We conducted a systematic review of evidence from randomized controlled trials to answer the following research question: What are the relative effects of different classes of antihypertensive drugs in reducing the incidence of cardiovascular disease outcomes for healthy people at risk of cardiovascular disease?
We searched MEDLINE, EMBASE, AMED (up to February 2011) and CENTRAL (up to May 2009), and reference lists in recent systematic reviews. Titles and abstracts were assessed for relevance and those potentially fulfilling our inclusion criteria were then assessed in full text. Two reviewers made independent assessments at each step. We selected the following main outcomes: total mortality, myocardial infarction and stroke. We also report on angina, heart failure and incidence of diabetes. We conducted a multiple treatments meta-analysis using random-effects models. We assessed the quality of the evidence using the GRADE-instrument.
We included 25 trials. Overall, the results were mixed, with few significant dif-ferences, and with no drug-class standing out as superior across multiple outcomes. The only significant finding for total mortality based on moderate to high quality evidence was that beta-blockers (atenolol) were inferior to angiotensin receptor blockers (ARB) (relative risk (RR) 1.14; 95% credibility interval (CrI) 1.02 to 1.28). Angiotensin converting enzyme (ACE)-inhibitors came out inferior to calcium-channel blockers (CCB) regarding stroke-risk (RR 1.19; 1.03 to 1.38), but superior regarding risk of heart failure (RR 0.82; 0.69 to 0.94), both based on moderate quality evidence. Diuretics reduced the risk of myocardial infarction compared to beta-blockers (RR 0.82; 0.68 to 0.98), and lowered the risk of heart failure compared to CCB (RR 0.73; 0.62 to 0.84), beta-blockers (RR 0.73; 0.54 to 0.96), and alpha-blockers (RR 0.51; 0.40 to 0.64). The risk of diabetes increased with diuretics compared to ACE-inhibitors (RR 1.43; 1.12 to 1.83) and CCB (RR 1.27; 1.05 to 1.57).
Based on the available evidence, there seems to be little or no difference between commonly used blood pressure lowering medications for primary prevention of cardiovascular disease. Beta-blockers (atenolol) and alpha-blockers may not be first-choice drugs as they were the only drug-classes that were not significantly superior to any other, for any outcomes.
Review registration: CRD database ("PROSPERO") CRD42011001066
The FGB gene codes for fibrinogen-beta, a polypeptide of the coagulation factor fibrinogen, which is positively associated with cardiovascular diseases. Studies show ACE inhibitors lower plasma fibrinogen concentrations, whereas diuretics and calcium channel blockers do not. Since carriers of the FGB-455 minor “A” allele have higher levels of fibrinogen while ACE inhibitors lower it, we hypothesize that “A” allele carriers benefit more from antihypertensive treatment with ACE inhibitors than calcium channel blockers or diuretics, relative to “GG” genotype individuals.
The GenHAT study (ancillary to ALLHAT) genotyped hypertensive participants for several hypertension-related candidate genes, making this a post-hoc analysis of a randomized trial. In total, 90.1% of the ALLHAT population was successfully genotyped for FGB-455. We included participants (n=30,076) randomized to one of three antihypertensive medications (lisinopril, amlodipine, chlorthalidone), with two treatment comparisons: lisinopril versus chlorthalidone and lisinopril versus amlodipine. The primary outcome of ALLHAT/GenHAT was coronary heart disease, defined as fatal CHD or non-fatal MI, and secondary outcomes included stroke, heart failure, all-cause mortality and end-stage renal disease (ESRD) with mean follow-up time of 4.9 years. Genotype-by-treatment interactions (pharmacogenetic effects) were tested with Cox regression.
Stroke: Common “GG” homozygotes had higher risk on lisinopril versus amlodipine (HR=1.38, p<0.001), while minor “A” allele carriers had slightly lower risk (HR=0.96, p=0.76; p-value for interaction=0.03). Mortality: “GG” homozygotes had higher risk on lisinopril versus amlodipine (HR=1.12, p=0.02) or chlorthalidone (1.05, p=0.23), while “A” allele carriers had slightly lower risk (HR=0.92, p=0.33 for lisinopril versus amlodipine, HR=0.88, p=0.08 for lisinopril versus chlorthalidone; p-value for interactions 0.04 and 0.03, respectively). ESRD: “GG” homozygotes had higher risk on lisinopril versus chlorthalidone (HR=1.27, p=0.08), while “A” allele carriers had lower risk (HR=0.64, p=0.12; p-value for interaction=0.03).
There was evidence of pharmacogenetic effects of FBG-455 on stroke, ESRD and mortality, suggesting that relative to those homozygous for the common allele, variant allele carriers of the FGB gene at position -455 have a better outcome if randomized to lisinopril than chlorthalidone (for mortality and ESRD) or amlodipine (for mortality and stroke). For the models in which a pharmacogenetic effect was observed, the outcome rates among “GG” homozygotes were higher in those randomized to lisinopril versus amlodipine or chlorthalidone, whereas minor “A” allele carriers had lower event rates when randomized to lisinopril versus the other medications.
FGB -455; fibrinogen gene; pharmacogenetics; hypertension; antihypertensive medication; cardiovascular disease
Calcium channel blocker (CCB) toxicity, in particular that induced by verapamil and diltiazem, presents clinical challenges with no true antidote. Levosimendan, a calcium sensitizer, improves cardiac contractility in patients with heart failure. We tested the hypothesis that calcium channel sensitization will prolong survival in a rat model of severe verapamil poisoning.
This was a blinded, randomized, controlled animal study. Wistar rats (mean weight, 371 ± 50 g) were used. Verapamil (2.5 mg/ml) was infused at a rate of 37.5 mg/kg per hour. Bolus doses of levosimendan (5 μg/mL) were given at 0 min (12 μg/kg) and 5 min (18 μg/kg); saline control was of equal volume. The rats were intubated and maintained under general anesthesia with isoflurane. Electrocardiographic activity and core temperature were monitored during the poisoning and treatment phases. Each rat underwent femoral vein cannulation and was then randomized, in blinded fashion, to receive either levosimendan or an equal volume of saline at 0 and 5 minutes. Death, defined as 1 minute of asystole, was used as the primary endpoint.
Rats treated with levosimendan died before the control group (7.37 ± 0.7 min [n = 7] vs. 16.4 ± 4.2 [n = 7] [p=.053]). All animals experienced bradycardia prior to asystole.
Although levosimendan has the ability to sensitize and enhance binding of troponin C to Ca2+, this study did not show an improvement in survival time in the setting of verapamil toxicity. This may be attributed to levosimendan’s inhibition of phosphodiesterase, which possibly exacerbated the CCB-induced hypotension.
In this rat model, levosimendan as a solitary antidotal treatment for verapamil toxicity was not beneficial.
verapamil; toxicity; levosimendan
Polymorphisms in the endothelial nitric oxide synthase (NOS3) gene increase susceptibility to hypertension and cardiovascular disease. We examined genetic and pharmacogenetic associations between NOS3 polymorphisms, blood pressure (BP) control, and cardiovascular events in elderly, hypertensive coronary artery disease (CAD) patients.
Patients with CAD were randomly assigned to either verapamil SR– or atenolol-based antihypertensive treatment and followed for cardiovascular events. Cases (all-cause death, nonfatal myocardial infarction (MI), or nonfatal stroke) and an age-, sex-, race/ethnicity-matched control population were genotyped for the -786T>C and Glu298>Asp polymorphisms in NOS3. On-treatment BP and BP control were compared across genotype groups. Logistic regression was performed to estimate odds ratios (ORs) for the -786T>C and Glu298>Asp polymorphisms in the combined population and in randomized treatment groups.
Genotype data were available for 256 cases and 769 controls. Among controls, mean on-treatment BP differed according to -786T>C genotype (T/T 137/78 mm Hg, T/C 133/76 mm Hg, C/C 133/75 mm Hg; P = 0.0007 for systolic, P = 0.09 for diastolic) which corresponded to differing rates of BP control (T/T 63%, T/C 72%, C/C 88%; P = 0.002). Neither polymorphisms was associated with case status, with or without regard to assigned treatment.
The -786T>C, but not the Glu298>Asp variant of NOS3, may correlate with BP but do not appear to be associated with incident cardiovascular events in patients with established cardiovascular disease. The antihypertensive treatment approach did not appear to alter the genetic contribution to either BP control or cardiovascular events.
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
Background: Calcium Channel Blockers (CCBs) are now widely employed in the treatment of cardiovascular diseases and peri operative hypertension. It has been reported that calcium channel blockers inhibit neuromuscular transmission. They have been shown to increase the neuromuscular blockade produced by neuromuscular blocking agents in in-vitro muscle nerve preparations. The present study is undertaken to demonstrate the effect of calcium channel blocker, verapamil on neuromuscular transmission in albino rats.
Objectives: To study the neuromuscular blockade action of verapamil in albino rats.
Methods: Twenty four albino rats of either sex weigh 150-250gms are selected and are randomly divided into 4 equal groups. The experimental rats are divided into four groups of 6 rats each and they are given the following treatment.
Group 1(Control) - Normal saline (1ml/ kg),
Group 2 (Standard) - Pancuronium (0.04 mg/kg)
Group 3-Verapamil (2.5mg/kg),
Group 4-given Verapamil (10mg/kg).
The time of onset of hind limb paralysis and total duration of recovery are noted using inclined screen method.
Results: Analysis of the results of group 3 that was received 2.5mg/kg of Verapamil, there was no onset of paralysis, in group 4 that received injection Verapamil 10mg/kg, showed neuromuscular blockade activity. The mean onset of hind limb paralysis was delayed compared to standard group and the mean duration of hind limb paralysis was shorter than standard group. It was statistically significant (P≤ 0.05).
Interpretation and conclusion: It is generally held that external calcium is not necessary for the contraction of mammalian skeletal muscle, the demonstration of inward calcium currents that can be abolished by CCBs in these muscles prompted to re-examine the effect of Verapamil on the neuromuscular transmission. The present study allows us to determine the neuromuscular blockade activity of Verapamil.
Calcium channel blockers; Neuromuscular blocking agents; Hind limb Paralysis; Verapamil, and Pancuronium
Individual differences in the sensitivity to fentanyl, a widely used opioid analgesic, lead to different proper doses of fentanyl, which can hamper effective pain treatment. Voltage-activated Ca2+ channels (VACCs) play a crucial role in the nervous system by controlling membrane excitability and calcium signaling. Cav2.3 (R-type) VACCs have been especially thought to play critical roles in pain pathways and the analgesic effects of opioids. However, unknown is whether single-nucleotide polymorphisms (SNPs) of the human CACNA1E (calcium channel, voltage-dependent, R type, alpha 1E subunit) gene that encodes Cav2.3 VACCs influence the analgesic effects of opioids. Thus, the present study examined associations between fentanyl sensitivity and SNPs in the human CACNA1E gene in 355 Japanese patients who underwent painful orofacial cosmetic surgery, including bone dissection. We first conducted linkage disequilibrium (LD) analyses of 223 SNPs in a region that contains the CACNA1E gene using genomic samples from 100 patients, and a total of 13 LD blocks with 42 Tag SNPs were observed within and around the CACNA1E gene region. In the preliminary study using the same 100 genomic samples, only the rs3845446 A/G SNP was significantly associated with perioperative fentanyl use among these 42 Tag SNPs. In a confirmatory study using the other 255 genomic samples, this SNP was also significantly associated with perioperative fentanyl use. Thus, we further analyzed associations between genotypes of this SNP and all of the clinical data using a total of 355 samples. The rs3845446 A/G SNP was associated with intraoperative fentanyl use, 24 h postoperative fentanyl requirements, and perioperative fentanyl use. Subjects who carried the minor G allele required significantly less fentanyl for pain control compared with subjects who did not carry this allele. Although further validation is needed, the present findings show the possibility of the involvement of CACNA1E gene polymorphisms in fentanyl sensitivity.