Newly diagnosed cardiovascular disease in patients treated with immune checkpoint inhibitors: a retrospective analysis of patients at an academic tertiary care center.

BACKGROUND: Immune checkpoint inhibitors (ICIs) are a novel class of anticancer agents that have demonstrated clinical response for both solid and hematological malignancies. ICIs are associated with development of immune-related adverse events including cardiotoxicity. We estimated the incidence of newly diagnosed cardiovascular disease in patients treated with ICIs at a large, tertiary care center. METHODS: All patients with a cancer diagnosis who received any ICI treatment in the University of Florida's Integrated Data Repository from 2011 to 2017 were included. Cardiovascular disease was defined as a new ICD diagnosis code for cardiomyopathy, heart failure, arrhythmia, heart block, pericardial disease, or myocarditis after initiation of ICI treatment. RESULTS: Of 102,701 patients with a diagnosis of malignancy, 424 patients received at least one ICI. Sixty-two (14.6%) patients were diagnosed with at least one new cardiovascular disease after initiation of ICI therapy. Of the 374 patients receiving one ICI, 21 (5.6%) developed heart failure. Of the 49 patients who received two ICIs sequentially, three (6.1%) developed heart failure and/or cardiomyopathy. Incident cardiovascular disease was diagnosed at a median of 63 days after initial ICI exposure. One patient developed myocarditis 28 days after receiving nivolumab. Mortality in ICI treated patients with a concomitant diagnosis of incident cardiovascular disease was higher compared to those who did not (66.1% vs. 41.4%, odds ratio = 2.77, 1.55-4.95, p = 0.0006). CONCLUSIONS: This study suggests a high incidence of newly diagnosed cardiovascular disease after the initiation of ICI therapy in a real-world clinical setting.

Examination of Metoprolol Pharmacokinetics and Pharmacodynamics Across CYP2D6 Genotype-Derived Activity Scores.

Recent CYP2D6 phenotype standardization efforts by CYP2D6 activity score (AS) are based on limited pharmacokinetic (PK) and pharmacodynamic (PD) data. Using data from two independent clinical trials of metoprolol, we compared metoprolol PK and PD across CYP2D6 AS with the goal of determining whether the PK and PD data support the new phenotype classification. S-metoprolol apparent oral clearance (CLo), adjusted for clinical factors, was correlated with CYP2D6 AS (P < 0.001). The natural log of CLo was lower with an AS of 1 (7.6 ± 0.4 mL/minute) vs. 2-2.25 (8.3 ± 0.6 mL/minute; P = 0.012), similar between an AS of 1 and 1.25-1.5 (7.8 ± 0.5 mL/minute; P = 0.702), and lower with an AS of 1.25-1.5 vs. 2-2.25 (P = 0.03). There was also a greater reduction in heart rate with metoprolol among study participants with AS of 1 (-10.8 ± 5.5) vs. 2-2.25 (-7.1 ± 5.6; P < 0.001) and no significant difference between those with an AS of 1 and 1.25-1.5 (-9.2 ± 4.7; P = 0.095). These data highlight linear trends among CYP2D6 AS and metoprolol PK and PD, but inconsistencies with the phenotypes assigned by AS based on the current standards. Overall, this case study with metoprolol suggests that utilizing CYP2D6 AS, instead of collapsing AS into phenotype categories, may be the most precise approach for utilizing CYP2D6 pharmacogenomics in clinical practice.

Age-Related Changes in miRNA Expression Influence GSTZ1 and Other Drug Metabolizing Enzymes.

Previous work has shown that hepatic levels of human glutathione transferase zeta 1 (GSTZ1) protein, involved in tyrosine catabolism and responsible for metabolism of the investigational drug dichloroacetate, increase in cytosol after birth before reaching a plateau around age 7. However, the mechanism regulating this change of expression is still unknown, and previous studies showed that GSTZ1 mRNA levels did not correlate with GSTZ1 protein expression. In this study, we addressed the hypothesis that microRNAs (miRNAs) could regulate expression of GSTZ1. We obtained liver samples from donors aged less than 1 year or older than 13 years and isolated total RNA for use in a microarray to identify miRNAs that were downregulated in the livers of adults compared with children. From a total of 2578 human miRNAs tested, 63 miRNAs were more than 2-fold down-regulated in adults, of which miR-376c-3p was predicted to bind to the 3' untranslated region of GSTZ1 mRNA. There was an inverse correlation of miR-376c-3p and GSTZ1 protein expression in the liver samples. Using cell culture, we confirmed that miR-376c-3p could downregulate GSTZ1 protein expression. Our findings suggest that miR-376c-3p prevents production of GSTZ1 through inhibition of translation. These experiments further our understanding of GSTZ1 regulation. Furthermore, our array results provide a database resource for future studies on mechanisms regulating human hepatic developmental expression. SIGNIFICANCE STATEMENT: Hepatic glutathione transferase zeta 1 (GSTZ1) is responsible for metabolism of the tyrosine catabolite maleylacetoacetate as well as the investigational drug dichloroacetate. Through examination of microRNA (miRNA) expression in liver from infants and adults and studies in cells, we showed that expression of GSTZ1 is controlled by miRNA. This finding has application to the dosing regimen of the drug dichloroacetate. The miRNA expression profiles are provided and will prove useful for future studies of drug-metabolizing enzymes in infants and adults.

Effect of plasma MicroRNA on antihypertensive response to beta blockers in the Pharmacogenomic Evaluation of Antihypertensive Responses (PEAR) studies.

ß-blockers show variable efficacy as antihypertensives. Herein, we evaluated plasma miRNAs as biomarkers for defining antihypertensive response to ß-blockers. Expression of 22 ß-blocker pharmacodynamics-related miRNAs was assessed in baseline plasma samples from 30 responders and 30 non-responders to metoprolol from the PEAR-2 study (Discovery). Logistic regression was performed to identify miRNAs significantly associated with metoprolol response. Those miRNAs were profiled in baseline plasma samples from 25 responders and 25 non-responders to atenolol from the PEAR study (validation). In discovery, miR-101, miR-27a, miR-22, miR-19a, and let-7e were significantly associated with metoprolol response (P = 0.01, 0.017, 0.025, 0.025, and 0.04, respectively). In validation, miR-19a was significantly associated with atenolol response (P = 0.038). Meta-analysis between PEAR-2 and PEAR revealed significant association between miR-19a (P = 0.004), miR-101 (P = 0.006), and let-7e (P = 0.012) and ß-blocker response. Hence, miR-19a, miR-101, and let-7e, which regulate ß1-adrenergic receptor and other ß-blocker pharmacodynamics-related genes, may be biomarkers for antihypertensive response to ß-blockers.

Targeted sequencing identifies a missense variant in the BEST3 gene associated with antihypertensive response to hydrochlorothiazide.

Chromosome 12q15 was identified in Genetic Epidemiology of Response Assessment (GERA) and replicated in Pharmacogenomic Evaluation of Antihypertensive Responses (PEAR) for its association with blood pressure (BP) response to hydrochlorothiazide (HCTZ). However, the functional variant is unknown and we aimed to identify the likely functional variants through targeted sequencing. The chromosome 12q15 region was sequenced in 397 best and worst responders to HCTZ in PEAR (N=199) and GERA (N=198) hypertensive study participants. Logistic regression was used for the association analysis adjusting for age, sex, race, and principal components 1 and 2. For validation, the significant single nucleotide polymorphism was tested for association with the change in systolic (ΔSBP) and diastolic BP (ΔDBP) post-treatment in the entire PEAR (N=370) and GERA (N=570) cohorts. A novel missense polymorphism (G>A, Pro383Leu) in BEST3, rs61747221, was significantly associated with better HCTZ response (P=0.0021, odds ratio=2.05). It was validated in the entire cohort of PEAR (ΔSBP: P=0.021, ß=-1.60, ΔDBP: P=0.023, ß=-1.08) and GERA (ΔSBP: P=0.028, ß=-1.95, ΔDBP: P=0.032, ß=-1.28). BEST3 encodes the calcium sensitive chloride channel in the vascular smooth muscle implicated in the regulation of BP, especially in response to vasoconstrictors like angiotensin II. These results suggest that BEST3 is involved in the chronic BP lowering mechanism of thiazides and highlight its importance as a genetic predictor of the BP response to thiazide diuretics.

Blood pressure signature genes and blood pressure response to thiazide diuretics: results from the PEAR and PEAR-2 studies.

BACKGROUND: Recently, 34 genes had been associated with differential expression relative to blood pressure (BP)/ hypertension (HTN). We hypothesize that some of the genes associated with BP/HTN are also associated with BP response to antihypertensive treatment with thiazide diuretics. METHODS: We assessed these 34 genes for association with differential expression to BP response to thiazide diuretics with RNA sequencing in whole blood samples from 150 hypertensive participants from the Pharmacogenomic Evaluation of Antihypertensive Responses (PEAR) and PEAR-2 studies. PEAR white and PEAR-2 white and black participants (n = 50 for each group) were selected based on the upper and lower quartile of BP response to hydrochlorothiazide (HCTZ) and to chlorthalidone. RESULTS: FOS, DUSP1 and PPP1R15A were differentially expressed across all cohorts (meta-analysis p-value < 2.0 × 10- 6), and responders to HCTZ or chlorthalidone presented up-regulated transcripts. Rs11065987 in chromosome 12, a trans-eQTL for expression of FOS, PPP1R15A and other genes, is also associated with BP response to HCTZ in PEAR whites (SBP: ß = - 2.1; p = 1.7 × 10- 3; DBP: ß = - 1.4; p = 2.9 × 10- 3). CONCLUSIONS: These findings suggest FOS, DUSP1 and PPP1R15A as potential molecular determinants of antihypertensive response to thiazide diuretics. TRIAL REGISTRATION: NCT00246519 , NCT01203852 www.clinicaltrials.gov.

SIRT1/HERC4 Locus Associated With Bisphosphonate-Induced Osteonecrosis of the Jaw: An Exome-Wide Association Analysis.

Osteonecrosis of the jaw (ONJ) is a rare, but serious drug side effect, mainly associated with the use of intravenous (iv) bisphosphonates (BPs). The purpose of this study was to identify genetic variants associated with ONJ in patients of European ancestry treated with iv BPs using whole-exome sequencing (WES). The WES phase 1 included 44 multiple myeloma patients (22 ONJ cases and 22 controls) and WES phase 2 included 17 ONJ patients with solid tumors. Multivariable logistic regression analysis was performed to estimate the odds ratios (ORs) and 95% confidence intervals (CI), adjusting for age, sex, and principal components for ancestry. Meta-analysis of WES phase 1 and 2 was performed to estimate the combined ORs. In silico analyses were then performed to identify expression quantitative loci (eQTL) single-nucleotide polymorphisms (SNPs) that are in high linkage disequilibrium (LD) with the top SNPs. The associations of the potentially functional SNPs were replicated and validated in an independent case-control study of 48 patients of European ancestry treated with iv BPs (19 ONJ cases and 29 controls). The top SNPs in the exome-wide association meta-analysis were two SNPs on chromosome 10: SIRT1 SNP rs7896005 and HERC4 SNP rs3758392 with identical OR of 0.07 (0.01-0.46; p = 3.83 × 10-5 ). In the in silico functional analyses, two promoter region SNPs (rs7894483 and rs3758391) were identified to be in high LD with the index SNPs and are eQTLs for SIRT1 gene in whole blood in the GTEx database. The ORs were 0.30 (0.10-0.88), 0.26 (0.12-0.55), and 0.26 (0.12-0.55) for the WES top SNP rs7896005 and two promoter SNPs rs7894483 and rs3758391, respectively, in the replication sample. In summary, we identified the SIRT1/HERC4 locus on chromosome 10 to be associated with iv BP-induced ONJ and two promoter SNPs that might be the potential genetic markers for this association. © 2017 The Authors.Journal of Bone and Mineral Research Published by Wiley Periodicals Inc.

Whole Transcriptome Sequencing Analyses Reveal Molecular Markers of Blood Pressure Response to Thiazide Diuretics.

Thiazide diuretics (TD) are commonly prescribed anti-hypertensives worldwide. However, <40% of patients treated with thiazide monotherapy achieve BP control. This study uses whole transcriptome sequencing to identify novel molecular markers associated with BP response to TD. We assessed global RNA expression levels in whole blood samples from 150 participants, representing patients in the upper and lower quartile of BP response to TD from the Pharmacogenomic Evaluation of Antihypertensive Responses (PEAR) (50 whites) and from PEAR-2 (50 whites and 50 blacks). In each study cohort, we performed poly-A RNA-sequencing in baseline samples from 25 responders and 25 non-responders to hydrochlorothiazide (HCTZ) or chlorthalidone. At FDR adjusted p-value < 0.05, 29 genes were differentially expressed in relation to HCTZ or chlorthalidone BP response in whites. For each differentially expressed gene, replication was attempted in the alternate white group and PEAR-2 blacks. CEBPD (meta-analysis p = 1.8 × 10-11) and TSC22D3 (p = 1.9 × 10-9) were differentially expressed in all 3 cohorts, and explain, in aggregate, 21.9% of response variability to TD. This is the first report of the use of transcriptome-wide sequencing data to identify molecular markers of antihypertensive drug response. These findings support CEBPD and TSC22D3 as potential biomarkers of BP response to TD.

Matrix Metalloproteinase Polymorphisms in Patients with Floppy Mitral Valve/Mitral Valve Prolapse (FMV/MVP) and FMV/MVP Syndrome.

BACKGROUND: It has been suggested that collagen abnormalities of the mitral valve are present in patients with floppy mitral valve (FMV)/mitral valve prolapse (MVP). Genetic factors determining collagen synthesis and degradation have not been well defined in these patients. This study was undertaken to determine whether selective polymorphisms of matrix metalloproteinase-2 (MMP2) or transforming growth factor-ß (TGFß), with known or putative effects on collagen turnover, are more frequent in FMV/MVP. METHODS: Single nucleotide polymorphisms (SNPs) in select genes related to collagen turnover, including MMP2 rs2285053, MMP2 rs243865, TGFß1 rs1800469, and TGFß2 rs900, were determined in 98 patients with FMV/MVP who had severe mitral regurgitation and compared to 99 controls. RESULTS: MMP2 rs243865 was the only SNP significantly associated with FMV/MVP as compared to the control (odds ratio 2.07, 95% CI 1.23-3.50, p = 0.006). MMP2 rs228503 was the only SNP significantly associated with the FMV/MVP syndrome as compared to patients with FMV/MVP without the syndrome (odds ratio 2.41, 95% CI 1.08-5.40, p = 0.032). CONCLUSION: The frequency of certain MMP2 polymorphisms is higher in patients with the FMV/MVP syndrome and patients with FMV/MVP without the syndrome. The data suggest that a genetic predisposition that alters collagen turnover may play a role in the pathogenesis and development of FMV/MVP.

Impact of the CYP2C19 genotype on voriconazole exposure in adults with invasive fungal infections.

OBJECTIVES: Voriconazole, a first-line agent for the treatment of invasive fungal infections (IFIs), is metabolized by CYP2C19. A significant proportion of patients fail to achieve therapeutic trough concentrations with standard weight-based voriconazole dosing, placing them at increased risk for treatment failure, which can be life threatening. We sought to test the association between the CYP2C19 genotype and subtherapeutic voriconazole concentrations in adults with IFIs. PATIENT AND METHODS: Adults receiving weight-based voriconazole dosing for the treatment of IFIs were genotyped for the CYP2C19*2, *3, and *17 polymorphisms, and CYP2C19 metabolizer phenotypes were inferred. Steady-state voriconazole trough plasma concentrations and the prevalence of subtherapeutic troughs (<2 mg/l) were compared between patients with the CYP2C19*17/*17 (ultrarapid metabolizer, UM) or *1/*17 (rapid metabolizer, RM) genotype versus those with other genotypes. Logistic regression, adjusting for clinical factors, was performed to estimate the odds of subtherapeutic concentrations. RESULTS: Of 70 patients included (mean age 52.5±18 years), 39% were RMs or UMs. Compared with patients with the other phenotypes, RMs/UMs had a lower steady-state trough concentration (4.26±2.2 vs. 2.86±2.3, P=0.0093) and a higher prevalence of subtherapeutic troughs (16 vs. 52%, P=0.0028), with an odds ratio of 5.6 (95% confidence interval: 1.64-19.24, P=0.0044). CONCLUSION: Our findings indicate that adults with the CYP2C19 RM or UM phenotype are more likely to have subtherapeutic concentrations with weight-based voriconazole dosing. These results corroborate previous findings in children and support the potential clinical utility of CYP2C19 genotype-guided voriconazole dosing to avoid underexposure in RMs and UMs.

CES1P1 variant -816A>C is not associated with hepatic carboxylesterase 1 expression and activity or antihypertensive effect of trandolapril.

PURPOSE: The majority of angiotensin-converting enzyme inhibitors (ACEIs) are synthesized as ester prodrugs that must be converted to their active forms in vivo in order to exert therapeutic effects. Hepatic carboxylesterase 1 (CES1) is the primary enzyme responsible for the bioactivation of ACEI prodrugs in humans. The genetic variant -816A>C (rs3785161) is a common variant located in the promoter region of the CES1P1 gene. Previous studies report conflicting results with regard to the association of this variant and therapeutic outcomes of CES1 substrate drugs. The purpose of this study was to determine the effect of the variant -816A>C on the activation of the ACEI prodrug trandolapril in human livers and the blood pressure (BP)-lowering effect of trandolapril in hypertensive patients. METHODS: The -816A>C genotypes and CES1 expression and activity on trandolapril activation were determined in 100 individual human liver samples. Furthermore, the association of the -816A>C variant and the BP lowering effect of trandolapril was evaluated in hypertensive patients who participated in the International Verapamil SR Trandolapril Study (INVEST). RESULTS: Our in vitro study demonstrated that hepatic CES1 expression and activity did not differ among different -816A>C genotypes. Moreover, we were unable to identify a clinical association between the BP lowering effects of trandolapril and -816A>C genotypes. CONCLUSIONS: We conclude that the -816A>C variant is not associated with interindividual variability in CES1 expression and activity or therapeutic response to ACEI prodrugs.

Pharmacogenomic Genome-Wide Meta-Analysis of Blood Pressure Response to ß-Blockers in Hypertensive African Americans.

African Americans suffer a higher prevalence of hypertension compared with other racial/ethnic groups. In this study, we performed a pharmacogenomic genome-wide association study of blood pressure (BP) response to ß-blockers in African Americans with uncomplicated hypertension. Genome-wide meta-analysis was performed in 318 African American hypertensive participants in the 2 Pharmacogenomic Evaluation of Antihypertensive Responses studies: 150 treated with atenolol monotherapy and 168 treated with metoprolol monotherapy. The analysis adjusted for age, sex, baseline BP and principal components for ancestry. Genome-wide significant variants with P<5×10(-8) and suggestive variants with P<5×10(-7) were evaluated in an additional cohort of 141 African Americans treated with the addition of atenolol to hydrochlorothiazide treatment. The validated variants were then meta-analyzed in these 3 groups of African Americans. Two variants discovered in the monotherapy meta-analysis were validated in the add-on therapy. African American participants heterozygous for SLC25A31 rs201279313 deletion versus wild-type genotype had better diastolic BP response to atenolol monotherapy, metoprolol monotherapy, and atenolol add-on therapy: -9.3 versus -4.6, -9.6 versus -4.8, and -9.7 versus -6.4 mm Hg, respectively (3-group meta-analysis P=2.5×10(-8), ß=-4.42 mm Hg per variant allele). Similarly, LRRC15 rs11313667 was validated for systolic BP response to ß-blocker therapy with 3-group meta-analysis P=7.2×10(-8) and ß=-3.65 mm Hg per variant allele. In this first pharmacogenomic genome-wide meta-analysis of BP response to ß-blockers in African Americans, we identified novel variants that may provide valuable information for personalized antihypertensive treatment in this group.

CYP2C19 and CES1 polymorphisms and efficacy of clopidogrel and aspirin dual antiplatelet therapy in patients with symptomatic intracranial atherosclerotic disease.

OBJECT Symptomatic intracranial atherosclerotic disease (ICAD) has a high risk of recurrent stroke. Genetic polymorphisms in CYP2C19 and CES1 are associated with adverse outcomes in cardiovascular patients, but have not been studied in ICAD. The authors studied CYP2C19 and CES1 single-nucleotide polymorphisms (SNPs) in symptomatic ICAD patients. METHODS Genotype testing for CYP2C19*2, (*)3, (*)8, (*)17 and CES1 G143E was performed on 188 adult symptomatic ICAD patients from 3 medical centers who were medically managed with clopidogrel and aspirin. Testing was performed prospectively at 1 center, and retrospectively from a DNA sample biorepository at 2 centers. Multiple logistic regression and Cox regression analysis were performed to assess the association of these SNPs with the primary endpoint, which was a composite of transient ischemic attack (TIA), stroke, myocardial infarction, or death within 12 months. RESULTS The primary endpoint occurred in 14.9% of the 188 cases. In multiple logistic regression analysis, the presence of the CYP2C19 loss of function (LOF) alleles *2, *3, and *8 in the medically managed patients was associated with lower odds of primary endpoint compared with wild-type homozygotes (odds ratio [OR] 0.13, 95% CI 0.03-0.62, p = 0.0101). Cox regression analysis demonstrated the CYP2C19 LOF carriers had a lower risk for the primary endpoint, with hazard ratio (HR) of 0.27 (95% CI 0.08-0.95), p = 0.041. A sensitivity analysis of a secondary composite endpoint of TIA, stroke, or death demonstrated a significant trend in multiple logistic regression analysis of CYP2C19 variants, with lower odds of secondary endpoint in patients carrying at least 1 LOF allele (*2, *3, *8) than in wild-type homozygotes (OR 0.27, 95% CI 0.06-1.16, p = 0.078). Cox regression analysis demonstrated that the carriers of CYP2C19 LOF alleles had a lower risk forthe secondary composite endpoint (HR 0.22, 95% CI 0.05-1.04, p = 0.056). CONCLUSIONS This is the first study examining genetic variants and their effects in symptomatic ICAD. Variant alleles of CYP2C19 (*2, *3, *8) were associated with lower odds of the primary and secondary composite endpoints. However, the direction of the association was opposite of what is expected based on this SNP. This may reflect an incomplete understanding of this genetic variation and its effect in symptomatic ICAD and warrants further investigations.

Osteonecrosis of the Jaw in the United States Food and Drug Administration's Adverse Event Reporting System (FAERS).

Osteonecrosis of the jaw (ONJ) is a serious adverse drug event that was initially reported with intravenous bisphosphonates (BPs) and more recently with other classes of drugs such as receptor activator of NF-κB ligand (RANKL) inhibitor, antiangiogenic agents, and mammalian target of rapamycin (m-TOR) inhibitors. The purpose of this study is to analyze the ONJ cases and the associated drugs in the US Food and Drug Administration's adverse event reporting system (FAERS). The FAERS database was queried for the adverse drug events reported from the first quarter of 2010 to the first quarter of 2014. The reporting odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for each queried drug. A total of 17,119 unique ONJ cases were identified. In the overall analysis, the drugs with the highest reporting ORs were BPs: pamidronate (OR = 498.9), zoledronate (OR = 171.7), and alendronate (OR = 63.6), whereas denosumab had lower ORs than all the BPs except for etidronate. The antiangiogenic and m-TOR inhibitors had the lowest ORs. In cancer patients who were treated for prevention of skeletal-related events (SREs), the reporting ORs for zoledronate and denosumab were 125.2 and 4.9, respectively. In patients with osteoporosis, the ORs were 1.1 (1.0-1.18) for zoledronate and 0.63 (0.56-0.70) for denosumab, respectively. Our analysis of the FAERS database showed that the intravenous BPs were associated with the highest risk for ONJ, RANKL inhibitor was associated with risk comparable to BPs used for osteoporosis such as etidronate, and the antiangiogenic agents and m-TOR inhibitors were associated with the lowest risk for ONJ. The high risk for ONJ with zoledronate and denosumab was mainly observed in those who were treated for prevention of SREs, whereas there was limited evidence for such risk in those who were treated for osteoporosis.

PTPRD gene associated with blood pressure response to atenolol and resistant hypertension.

OBJECTIVE: The aim of this study is to identify single-nucleotide polymorphisms (SNPs) influencing blood pressure (BP) response to the ß-blocker atenolol. METHODS: Genome-wide association analysis of BP response to atenolol monotherapy was performed in 233 white participants with uncomplicated hypertension in the pharmacogenomic evaluation of antihypertensive responses study. Forty-two polymorphisms with P less than 10 for association with either diastolic or systolic response to atenolol monotherapy were validated in four independent groups of hypertensive individuals (total n = 2114). RESULTS: In whites, two polymorphisms near the gene PTPRD (rs12346562 and rs1104514) were associated with DBP response to atenolol (P = 3.2 × 10 and P = 5.9 × 10, respectively) with directionally opposite association for response to hydrochlorothiazide in another group of 228 whites (P = 0.0018 and P = 0.00012). A different polymorphism (rs10739150) near PTPRD was associated with response to atenolol in 150 black hypertensive individuals (P = 8.25 × 10). rs12346562 had a similar trend in association with response to bisoprolol (a different ß-blocker) in 207 Finnish men in the genetics of drug responsiveness in essential hypertension study. In addition, an intronic single-nucleotide polymorphism (rs4742610) in the PTPRD gene was associated with resistant hypertension in whites and Hispanics in the international verapamil SR trandolapril study (meta-analysis P = 3.2 × 10). CONCLUSION: PTPRD was identified as a novel locus potentially associated with BP response to atenolol and resistant hypertension in multiple ethnic groups.

The influence of human GSTZ1 gene haplotype variations on GSTZ1 expression.

BACKGROUND/OBJECTIVES: The zeta-1 family isoform of GST biotransforms the investigational drug dichloroacetate (DCA) and certain other halogenated carboxylic acids. Haplotype variability in GSTZ1 influences the kinetics and, possibly, the toxicity of DCA. DCA metabolism correlates with expression of the GSTZ1 protein, so it is important to document variables that affect expression. Following up on a limited previous study, we tested the hypothesis that a coding single nucleotide polymorphism (SNP), the lysine (K) amino acid (E32>K) in GSTZ1 haplotypes linked to a promoter region SNP results in lower hepatic expression of GSTZ1. MATERIALS AND METHODS: The influence of K carrier and non-K carrier haplotypes on GSTZ1 expression was determined by analyzing 78 liver samples from individuals aged 7-84 years of various racial and ethnic backgrounds. GSTZ1 expression data were analyzed on the basis of the presence or absence of lysine 32. RESULTS: GSTZ1 protein expression differed significantly between K carrier and non-K carrier haplotypes (P=0.001) in Whites, but not in African-Americans (P=0.277). We attribute this difference in GSTZ1 expression among K carrier haplotypes in Whites to the linkage disequilibrium between the K or A allele from the G>A SNP (rs7975), within the promoter G>A-1002 SNP (rs7160195) A allele. There is no linkage disequilibrium between these two polymorphisms in African-Americans. CONCLUSION: We conclude that the lower expression of GSTZ1 in Whites who possess the K carrier haplotype results in lower enzymatic activity and slower metabolism of DCA, compared with those who possess the non-K carrier haplotype. These results further define safe, genetics-based dosing regimens for chronic DCA administration.

Floppy mitral valve/mitral valve prolapse syndrome: Beta-adrenergic receptor polymorphism may contribute to the pathogenesis of symptoms.

BACKGROUND: Certain patients with floppy mitral valve (FMV)/mitral valve prolapse (MVP) may have symptoms that cannot be explained on the severity of mitral valvular regurgitation (MVR) alone; hypersensitivity to adrenergic stimulation has been suggested in this group defined as the FMV/MVP syndrome. METHODS: Ninety-eight patients (75 men, 23 women) with mitral valve surgery for FMV/MVP were studied. Of those 41 (42%) had symptoms consistent with FMV/MVP syndrome [29 men (39%), 12 women (52%)]; median age of symptom onset was 30 years (range 10-63 years) and median duration of symptoms prior to valve surgery was 16 years (range 3-50 years). Ninety-nine individuals (70 men, 29 women) without clinical evidence of any disease were used as controls. Genotyping of ß1 and ß2 adrenergic receptors was performed. RESULTS: ß-Adrenergic receptor genotypes (ß1 and ß2) were similar between control and overall FMV/MVP patients. Subgroup analysis of patients, however, demonstrated that the genotype C/C at position 1165 resulting in 389 Arg/Arg of the ß1 receptor was more frequent in women compared to those without FMV/MVP syndrome and to normal control women (p<0.025). This polymorphism may be related to hypersensitivity to adrenergic stimulation as reported previously in these patients. CONCLUSION: This study shows a large proportion of patients with FMV/MVP, predominantly women, had symptoms consistent with the FMV/MVP syndrome for many years prior to the development of significant MVR, and thus symptoms cannot be attributed to the severity of MVR alone. Further, women with FMV/MVP syndrome, symptoms at least partially may be related to ß1-adrenergic receptor polymorphism, which has been shown previously to be associated with a hyperresponse to adrenergic stimulation.

Pyrosequencing of the CYP2C9 -1766T>C polymorphism as a means of detecting the CYP2C9*8 allele.

The CYP2C9 c.449G>A (p.R150H, rs7900194) polymorphism, which confers the CYP2C9*8 allele, is common in persons of African descent and results in reduced clearance of the narrow therapeutic index drugs, warfarin and phenytoin. Because of significant homology in DNA sequence at the 449G>A locus among CYP2C genes, the 449G>A variant cannot be reliably detected via PCR-based genotyping assays that require a short PCR product, such as pyrosequencing. Herein, we propose genotyping for the CYP2C9 c.-1766T>C polymorphism via pyrosequencing as an alternative and accurate means of identifying the CYP2C9*8 allele.

The influence of the CYP2C19*10 allele on clopidogrel activation and CYP2C19*2 genotyping.

BACKGROUND/OBJECTIVES: The polymorphic hepatic enzyme CYP2C19 catalyzes the metabolism of clinically important drugs such as clopidogrel, proton-pump inhibitors, and others and clinical pharmacogenetic testing for clopidogrel is increasingly common. The CYP2C19*10 single-nucleotide polymorphism (SNP) is located 1 bp upstream the CYP2C19*2 SNP. Despite the low frequency of the CYP2C19*10 allele, its impact on metabolism of CYP2C19 substrates and CYP2C19*2 genotyping makes it an important SNP to consider for pharmacogenetic testing of CYP2C19. However, the effect of the CYP2C19*10 allele on clopidogrel metabolism has not been explored to date. METHODS: We measured the enzymatic activity of the CYP2C19.10 protein against clopidogrel. DNA samples from two clinical studies were genotyped for CYP2C19*2 and *10 by pyrosequencing genotyping method. RESULTS: The catalytic activity of CYP2C19.10 in the biotransformation of clopidogrel and 2-oxo-clopidogrel was significantly decreased relative to the wild-type CYP2C19.1B. We also reported that the CYP2C19*10 SNP interferes with the CYP2C19*2 TaqMan genotyping assay, resulting in miscalling of CYP2C19*10/*2 as CYP2C19*2/*2. CONCLUSIONS: Our data provide evidence that CYP2C19.10 variant partially metabolizes clopidogrel and 2-oxo-clopidogrel, and the presence of CYP2C19*10 allele affects the CY2C19*2 TaqMan genotyping assay and results in misclassification of CYP2C19*10/*2 as CYP2C19*2/*2.