McDonough, Caitrin W.

Introduction: Hydrochlorothiazide (HCTZ) is among the most commonly prescribed antihypertensives in the US, yet <50% of HCTZ treated patients achieve blood pressure (BP) control. Hypothesis: Integrating metabolomic and genomic profiles of HCTZ treated patients could identify novel pathways/biomarkers for optimizing the use of HCTZ. Methods: Primary analysis included 228 white hypertensives treated with HCTZ from the Pharmacogenomic Evaluation of Antihypertensive Response (PEAR) study. Genotyping was determined via Illumina Omni 1M-Quad Chip and untargeted metabolomics was performed on baseline fasting plasma samples using a GC-TOF MS platform. Pathway analysis was used to integrate metabolites significantly associated with HCTZ BP response (FDR<.05) and genetic signals at p<5x10-5 from HCTZ BP genome-wide analysis. Replication was conducted in another 212 white HCTZ treated patients. Replicated genetic signals were used to create a BP response score by summing their BP lowering alleles. We validated this score by testing it in 196 white HCTZ treated patients in the Genetic Epidemiology of Responses to Antihypertensives (GERA) study. Results: Thirteen metabolites were significantly associated with HCTZ systolic BP (SBP) and diastolic BP (DBP) responses (FDR<.05). Metabolomics-genomics integration revealed significant metabolites along with rs2727563 PRKAG2, rs12604940 DCC, and rs13262930 EPHX2, in the netrin signalling pathway (p=1x10-5), as potential markers significantly influencing HCTZ BP response. We successfully replicated those 3 genetic signals and added their alleles to create a response score which explained 11.3% and 11.9% of the variability to HCTZ SBP and DBP responses, respectively. We found that patients carrying one “response” allele had a significantly worse response than carriers of six alleles (ΔSBP/ΔDBP: -1.5/1.2 vs -16.3/-10.4 mmHg, respectively, SBP score p=1x10-8 and DBP score p=3x10-9). We further validated this response score by testing it in the GERA (DBP score p=0.03, SBP score p=0.07). Conclusion: This study highlights the power of using different omics to identify novel pathways/biomarkers of drug response, and suggests that PRKAG2, DCC and EPHX2 might be important determinants of HCTZ BP response.

Abstract This study aimed to investigate the influence of stroke lesions in predefined highly interconnected (rich‐club) brain regions on functional outcome post‐stroke, determine their spatial specificity and explore the effects of biological sex on their relevance. We analyzed MRI data recorded at index stroke and ~3‐months modified Rankin Scale (mRS) data from patients with acute ischemic stroke enrolled in the multisite MRI‐GENIE study. Spatially normalized structural stroke lesions were parcellated into 108 atlas‐defined bilateral (sub)cortical brain regions. Unfavorable outcome (mRS > 2) was modeled in a Bayesian logistic regression framework. Effects of individual brain regions were captured as two compound effects for (i) six bilateral rich club and (ii) all further non‐rich club regions. In spatial specificity analyses, we randomized the split into “rich club” and “non‐rich club” regions and compared the effect of the actual rich club regions to the distribution of effects from 1000 combinations of six random regions. In sex‐specific analyses, we introduced an additional hierarchical level in our model structure to compare male and female‐specific rich club effects. A total of 822 patients (age: 64.7[15.0], 39% women) were analyzed. Rich club regions had substantial relevance in explaining unfavorable functional outcome (mean of posterior distribution: 0.08, area under the curve: 0.8). In particular, the rich club‐combination had a higher relevance than 98.4% of random constellations. Rich club regions were substantially more important in explaining long‐term outcome in women than in men. All in all, lesions in rich club regions were associated with increased odds of unfavorable outcome. These effects were spatially specific and more pronounced in women.

Introduction: Genetic studies of early-onset disease have been an effective strategy to identify novel pathways and drug targets generalizable also to later-onset disease. Few studies have investigated the sex-specific genetic associations with early-onset ischemic stroke even though several features of ischemic stroke differ between males and females. We hypothesized that stratifying the GWAS by sex would reveal novel stroke loci. Methods: We performed a transethnic ischemic stroke GWAS of 3,056 female cases and 4,462 male cases < 60 years-old and 16,192 and 16,048 sex-matched controls, respectively, from the Early Onset Stroke Genetics Consortium. Results: We identified a significant association in women with a locus in close proximity to TMX1 , a transmembrane platelet protein that inhibits platelet function. Additionally, we identified 2 other suggestive (P < 5 x 10 -6 ) loci in females (see Table), i.e., at APOH , which encodes beta2-glycoprotein I, an established GWAS locus for lipoprotein(a), and LRFN2 which has been previously reported to associate with obesity-related measures and type II diabetes. We observed suggestive evidence for association in males with MMP3/MMP12 , a known stroke susceptibility locus. Conclusions: Despite a very modest sample size, sex-specific analyses identified suggestive associations at biologically important novel loci in females and a known stroke locus in males. Further studies of sex-specific associations in both early- and later-onset ischemic stroke are needed.

Abstract Stroke represents a considerable burden of disease for both men and women. However, a growing body of literature suggests clinically relevant sex differences in the underlying causes, presentations and outcomes of acute ischaemic stroke. In a recent study, we reported sex divergences in lesion topographies: specific to women, acute stroke severity was linked to lesions in the left-hemispheric posterior circulation. We here determined whether these sex-specific brain manifestations also affect long-term outcomes. We relied on 822 acute ischaemic patients [age: 64.7 (15.0) years, 39% women] originating from the multi-centre MRI-GENIE study to model unfavourable outcomes (modified Rankin Scale &gt;2) based on acute neuroimaging data in a Bayesian hierarchical framework. Lesions encompassing bilateral subcortical nuclei and left-lateralized regions in proximity to the insula explained outcomes across men and women (area under the curve = 0.81). A pattern of left-hemispheric posterior circulation brain regions, combining left hippocampus, precuneus, fusiform and lingual gyrus, occipital pole and latero-occipital cortex, showed a substantially higher relevance in explaining functional outcomes in women compared to men [mean difference of Bayesian posterior distributions (men – women) = −0.295 (90% highest posterior density interval = −0.556 to −0.068)]. Once validated in prospective studies, our findings may motivate a sex-specific approach to clinical stroke management and hold the promise of enhancing outcomes on a population level.

Abstract While chronological age is one of the most influential determinants of post-stroke outcomes, little is known of the impact of neuroimaging-derived biological brain age. We here first examine whether radiomics analysis of the texture of brain T2-FLAIR MRI images can be used to predict brain age in stroke patients. We then assess the clinical determinants of accelerated brain aging and, finally, its impact on post-stroke functional outcomes. Leveraging a multisite cohort of 4,163 ischemic stroke patients, we show that older-appearing patients have more hypertension, diabetes mellitus, prior strokes, and smoking history and are more likely to develop worse post-stroke outcomes than their younger-appearing counterparts. Our results strengthen the importance of preventive medicine for maintaining brain health in stroke patients as they age and suggest a novel methodology to capture previously undescribed prognostic information available on commonly acquired MRI sequences during routine stroke care.

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

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

Abstract BACKGROUND Interindividual variability in blood pressure (BP) response to antihypertensives has been reported. Although plasma renin activity (PRA) is a potential biomarker for personalizing antihypertensive therapy in European American (EA) and African American (AA) hypertensives, clinical utility of PRA-guided prescribing is incompletely understood. METHODS Using systematic-phased approach, PRA’s clinical utility was assessed. After categorizing by baseline PRA, clinic systolic BP (SBP) responses to metoprolol and chlorthalidone were compared in 134 EAs and 102 AAs enrolled in the Pharmacogenomics Evaluation of Antihypertensive Responses-2 (PEAR-2) trial. Receiver operating characteristic (ROC) analysis was conducted in EAs. Data from PEAR-2 AAs were used to estimate an optimal PRA cut point using multivariable linear regression models. The derived cut point in AAs was tested in a meta-analysis of 2 independent AA cohorts, and its sensitivity and specificity were assessed. RESULTS EAs with PRA &lt; 0.65 ng/ml/hour had a greater decrease in SBP to chlorthalidone than metoprolol (by –15.9 mm Hg, adjusted P &lt; 0.0001), whereas those with PRA ≥ 0.65 ng/ml/hour had a greater decrease in SBP to metoprolol than chlorthalidone (by 3.3 mm Hg, adjusted P = 0.04). Area under ROC curve (0.69, P = 0.0001) showed that PRA can predict SBP response among EAs. However, we observed no association between PRA and SBP response in PEAR-2 AAs. Among independent AA cohorts, those with PRA ≥ 1.3 ng/ml/hour (PEAR-2-derived cut point) responded better to atenolol/candesartan than hydrochlorothiazide (meta-analysis P = 0.01). However, sensitivity of the derived cut point was 10%. CONCLUSIONS PRA at the previously established 0.60–0.65 ng/ml/hour cut point is an effective predictive biomarker of BP response in EAs. However, we were unable to identify PRA cut point that could be used to guide antihypertensive selection in AAs. TRIAL REGISTRATION NCT01203852, NCT00246519, NCT00005520.