PATJ Low Frequency Variants Are Associated With Worse Ischemic Stroke Functional Outcome.

RATIONALE: Ischemic stroke is among the leading causes of adult disability. Part of the variability in functional outcome after stroke has been attributed to genetic factors but no locus has been consistently associated with stroke outcome. OBJECTIVE: Our aim was to identify genetic loci influencing the recovery process using accurate phenotyping to produce the largest GWAS (genome-wide association study) in ischemic stroke recovery to date. METHODS AND RESULTS: A 12-cohort, 2-phase (discovery-replication and joint) meta-analysis of GWAS included anterior-territory and previously independent ischemic stroke cases. Functional outcome was recorded using 3-month modified Rankin Scale. Analyses were adjusted for confounders such as discharge National Institutes of Health Stroke Scale. A gene-based burden test was performed. The discovery phase (n=1225) was followed by open (n=2482) and stringent joint-analyses (n=1791). Those cohorts with modified Rankin Scale recorded at time points other than 3-month or incomplete data on previous functional status were excluded in the stringent analyses. Novel variants in PATJ (Pals1-associated tight junction) gene were associated with worse functional outcome at 3-month after stroke. The top variant was rs76221407 (G allele, ß=0.40, P=1.70×10-9). CONCLUSIONS: Our results identify a set of common variants in PATJ gene associated with 3-month functional outcome at genome-wide significance level. Future studies should examine the role of PATJ in stroke recovery and consider stringent phenotyping to enrich the information captured to unveil additional stroke outcome loci.

A genome-wide association study of IgM antibody against phosphorylcholine: shared genetics and phenotypic relationship to chronic lymphocytic leukemia.

Phosphorylcholine (PC) is an epitope on oxidized low-density lipoprotein (oxLDL), apoptotic cells and several pathogens like Streptococcus pneumoniae. Immunoglobulin M against PC (IgM anti-PC) has the ability to inhibit uptake of oxLDL by macrophages and increase clearance of apoptotic cells. From our genome-wide association studies (GWASs) in four European-ancestry cohorts, six single nucleotide polymorphisms (SNPs) in 11q24.1 were discovered (in 3002 individuals) and replicated (in 646 individuals) to be associated with serum level of IgM anti-PC (the leading SNP rs35923643-G, combined ß = 0.19, 95% confidence interval 0.13-0.24, P = 4.3 × 10-11). The haplotype tagged by rs35923643-G (or its proxy SNP rs735665-A) is also known as the top risk allele for chronic lymphocytic leukemia (CLL), and a main increasing allele for general IgM. By using summary GWAS results of IgM anti-PC and CLL in the polygenic risk score (PRS) analysis, PRS on the basis of IgM anti-PC risk alleles positively associated with CLL risk (explained 0.6% of CLL variance, P = 1.2 × 10-15). Functional prediction suggested that rs35923643-G might impede the binding of Runt-related transcription factor 3, a tumor suppressor playing a central role in the immune regulation of cancers. Contrary to the expectations from the shared genetics between IgM anti-PC and CLL, an inverse relationship at the phenotypic level was found in a nested case-control study (30 CLL cases with 90 age- and sex-matched controls), potentially reflecting reverse causation. The suggested function of the top variant as well as the phenotypic association between IgM anti-PC and CLL risk needs replication and motivates further studies.

Genetically Determined Risk of Depression and Functional Outcome After Ischemic Stroke.

Background and Purpose- Psychosocial factors can have implications for ischemic stroke risk and recovery. This study investigated the effect of genetically determined risk of depression on these outcomes using the Mendelian randomization (MR) framework. Methods- Genetic instruments for risk of depression were identified in a discovery genome-wide association study of 246 363 cases and 561 190 controls and further replicated in a separate population of 474 574 cases and 1 032 579 controls. Corresponding genetic association estimates for risk of ischemic stroke were taken from 60 341 cases and 454 450 controls, with those for functional outcome 3 months after ischemic stroke taken from an analysis of 6021 patients. Following statistical power calculation, inverse-variance weighted MR was performed to pool estimates across different instruments. The Cochran Q heterogeneity test, weighted median MR, and MR pleiotropy residual sum and outlier were used to explore possible bias relating to inclusion of pleiotropic variants. Results- There was no MR evidence for an effect of genetically determined risk of depression on ischemic stroke risk. Although suffering low statistical power, the main inverse-variance weighted MR analysis was suggestive of a detrimental effect of genetically determined risk of depression on functional outcome after ischemic stroke (odds ratio of poor outcome [modified Rankin Scale, ≥3] per 1-SD increase in genetically determined risk of depression, 1.81; 95% CI, 0.98-3.35; P=0.06). There was no evidence of heterogeneity between MR estimates produced by different instruments (Q P=0.26). Comparable MR estimates were obtained with weighted median MR (odds ratio, 2.57; 95% CI, 1.05-6.25; P=0.04) and MR pleiotropy residual sum and outlier (odds ratio, 1.81; 95% CI, 0.95-3.46; P=0.08). Conclusions- We found no MR evidence of genetically determined risk of depression affecting ischemic stroke risk but did find consistent MR evidence suggestive of a possible effect on functional outcome after ischemic stroke. Given the widespread prevalence of depression-related morbidity, these findings could have implications for prognostication and personalized rehabilitation after stroke.

Homeostatic Chemokines and Prognosis in Patients With Acute Coronary Syndromes.

BACKGROUND: The chemokines CCL19 and CCL21 are up-regulated in atherosclerotic disease and heart failure, and increased circulating levels are found in unstable versus stable coronary artery disease. OBJECTIVES: The purpose of this study was to evaluate the prognostic value of CCL19 and CCL21 in acute coronary syndrome (ACS). METHODS: CCL19 and CCL21 levels were analyzed in serum obtained from ACS patients (n = 1,146) on the first morning after hospital admission. Adjustments were made for GRACE (Global Registry of Acute Coronary Events) score, left ventricular ejection fraction, pro-B-type natriuretic peptide, troponin I, and C-reactive protein levels. RESULTS: The major findings were: 1) those having fourth quartile levels of CCL21 on admission of ACS had a significantly higher long-term (median 98 months) risk of major adverse cardiovascular events (MACE) and myocardial infarction in fully adjusted multivariable models; 2) high CCL21 levels at admission were also independently associated with MACE and cardiovascular mortality during short-time (3 months) follow-up; and 3) high CCL19 levels at admission were associated with the development of heart failure. CONCLUSIONS: CCL21 levels are independently associated with outcome after ACS and should be further investigated as a promising biomarker in these patients.

Genome-wide association meta-analysis of functional outcome after ischemic stroke.

OBJECTIVE: To discover common genetic variants associated with poststroke outcomes using a genome-wide association (GWA) study. METHODS: The study comprised 6,165 patients with ischemic stroke from 12 studies in Europe, the United States, and Australia included in the GISCOME (Genetics of Ischaemic Stroke Functional Outcome) network. The primary outcome was modified Rankin Scale score after 60 to 190 days, evaluated as 2 dichotomous variables (0-2 vs 3-6 and 0-1 vs 2-6) and subsequently as an ordinal variable. GWA analyses were performed in each study independently and results were meta-analyzed. Analyses were adjusted for age, sex, stroke severity (baseline NIH Stroke Scale score), and ancestry. The significance level was p < 5 × 10-8. RESULTS: We identified one genetic variant associated with functional outcome with genome-wide significance (modified Rankin Scale scores 0-2 vs 3-6, p = 5.3 × 10-9). This intronic variant (rs1842681) in the LOC105372028 gene is a previously reported trans-expression quantitative trait locus for PPP1R21, which encodes a regulatory subunit of protein phosphatase 1. This ubiquitous phosphatase is implicated in brain functions such as brain plasticity. Several variants detected in this study demonstrated suggestive association with outcome (p < 10-5), some of which are within or near genes with experimental evidence of influence on ischemic stroke volume and/or brain recovery (e.g., NTN4, TEK, and PTCH1). CONCLUSIONS: In this large GWA study on functional outcome after ischemic stroke, we report one significant variant and several variants with suggestive association to outcome 3 months after stroke onset with plausible mechanistic links to poststroke recovery. Future replication studies and exploration of potential functional mechanisms for identified genetic variants are warranted.

A Genome-wide Study of Common and Rare Genetic Variants Associated with Circulating Thrombin Activatable Fibrinolysis Inhibitor.

Thrombin-activatable fibrinolysis inhibitor (TAFI) plays a central role in haemostasis, and plasma TAFI concentrations are heritable. Candidate gene studies have identified several variants within the gene encoding TAFI, CPB2, that explain part of the estimated heritability. Here, we describe an exploratory genome-wide association study to identify novel variants within and outside of the CPB2 locus that influence plasma concentrations of intact TAFI and/or the extent of TAFI activation (measured by released TAFI activation peptide, TAFI-AP) amongst 3,260 subjects from Southern Sweden. We also explored the role of rare variants on the HumanExome BeadChip. We confirmed the association with previously reported common variants in CPB2 for both intact TAFI and TAFI-AP, and discovered novel associations with variants in putative CPB2 enhancers. We identified a gene-based association with intact TAFI at CPB2 (PSKAT-O = 2.8 × 10-8), driven by two novel rare nonsynonymous single nucleotide polymorphisms (SNPs; I420N and D177G). Carriers of the rare variant of D177G (rs140446990; MAF 0.2%) had lower intact TAFI and TAFI-AP concentrations compared with non-carriers (intact TAFI, geometric mean 53 vs. 78%, PT-test = 5 × 10-7; TAFI-AP 63 vs. 99%, PT-test = 7.2 × 10-4). For TAFI-AP, we identified a genome-wide significant association at an intergenic region of chromosome 3p14.1 and five gene-based associations (all PSKAT-O < 5 × 10-6). Using well-characterized assays together with a genome-wide association study and a rare-variant approach, we verified CPB2 to be the primary determinant of TAFI concentrations and identified putative secondary loci (candidate variants and genes) associated with intact TAFI and TAFI-AP that require independent validation.

Serum neutrophil gelatinase-associated lipocalin (NGAL) concentration is independently associated with mortality in patients with acute coronary syndrome.

BACKGROUND: Circulating neutrophil gelatinase-associated lipocalin (NGAL) concentration increases in cardiovascular disease, but the long-term prognostic value of NGAL concentration has not been evaluated in acute coronary syndrome (ACS). We examined the association between NGAL concentration and prognosis in patients with ACS after non-ST-elevation myocardial infarction (NSTEMI) or STEMI. METHODS AND RESULTS: NGAL concentration was measured in blood from 1121 consecutive ACS patients (30% women, mean age 65 years) on the first morning after admission. After adjustment for 14 variables, NGAL concentration predicted long-term (median 167 months) mortality (hazard ratio [HR] 1.33, 95% confidence interval [CI] 1.10-1.61, P = 0.003) for quartile (q) 4 of NGAL concentration. NGAL concentrations also predicted long-term mortality (HR = 1.63, 95% CI 1.31-2.03, P < 0.001, N = 741) when adjusting for Global Registry of Acute Coronary Events (GRACE) score, left ventricular ejection fraction (LVEF), and pro-B-type natriuretic peptide (proBNP) and C-reactive protein (CRP) concentrations. With these adjustments, NGAL concentration predicted long-term mortality in NSTEMI patients (HR = 2.02, 95% CI 1.50-2.72, P < 0.001) but not in STEMI patients (HR = 1.32, 95% CI 0.95-1.83, P = 0.100). In all patients, the combination of NGAL concentration and GRACE score yielded an HR of 5.56 (95% CI 4.37-7.06, P < 0.001) for q4/q4 for both variables. CONCLUSION: NGAL concentration in ACS is associated with long-term prognosis after adjustment for clinical confounders. Measuring circulating NGAL concentration may help to identify patients-particularly those with NSTEMI-needing closer follow-up after ACS.

Causal relationship between obesity and serum testosterone status in men: A bi-directional mendelian randomization analysis.

CONTEXT: Obesity in men is associated with low serum testosterone and both are associated with several diseases and increased mortality. OBJECTIVES: Examine the direction and causality of the relationship between body mass index (BMI) and serum testosterone. DESIGN: Bi-directional Mendelian randomization (MR) analysis on prospective cohorts. SETTING: Five cohorts from Denmark, Germany and Sweden (Inter99, SHIP, SHIP Trend, GOOD and MrOS Sweden). PARTICIPANTS: 7446 Caucasian men, genotyped for 97 BMI-associated SNPs and three testosterone-associated SNPs. MAIN OUTCOME MEASURES: BMI and serum testosterone adjusted for age, smoking, time of blood sampling and site. RESULTS: 1 SD genetically instrumented increase in BMI was associated with a 0.25 SD decrease in serum testosterone (IV ratio: -0.25, 95% CI: -0.42--0.09, p = 2.8*10-3). For a body weight reduction altering the BMI from 30 to 25 kg/m2, the effect would equal a 13% increase in serum testosterone. No association was seen for genetically instrumented testosterone with BMI, a finding that was confirmed using large-scale data from the GIANT consortium (n = 104349). CONCLUSIONS: Our results suggest that there is a causal effect of BMI on serum testosterone in men. Population level interventions to reduce BMI are expected to increase serum testosterone in men.

Novel Genetic Variants Associated With Increased Vertebral Volumetric BMD, Reduced Vertebral Fracture Risk, and Increased Expression of SLC1A3 and EPHB2.

Genome-wide association studies (GWASs) have revealed numerous loci for areal bone mineral density (aBMD). We completed the first GWAS meta-analysis (n = 15,275) of lumbar spine volumetric BMD (vBMD) measured by quantitative computed tomography (QCT), allowing for examination of the trabecular bone compartment. SNPs that were significantly associated with vBMD were also examined in two GWAS meta-analyses to determine associations with morphometric vertebral fracture (n = 21,701) and clinical vertebral fracture (n = 5893). Expression quantitative trait locus (eQTL) analyses of iliac crest biopsies were performed in 84 postmenopausal women, and murine osteoblast expression of genes implicated by eQTL or by proximity to vBMD-associated SNPs was examined. We identified significant vBMD associations with five loci, including: 1p36.12, containing WNT4 and ZBTB40; 8q24, containing TNFRSF11B; and 13q14, containing AKAP11 and TNFSF11. Two loci (5p13 and 1p36.12) also contained associations with radiographic and clinical vertebral fracture, respectively. In 5p13, rs2468531 (minor allele frequency [MAF] = 3%) was associated with higher vBMD (ß = 0.22, p = 1.9 × 10-8 ) and decreased risk of radiographic vertebral fracture (odds ratio [OR] = 0.75; false discovery rate [FDR] p = 0.01). In 1p36.12, rs12742784 (MAF = 21%) was associated with higher vBMD (ß = 0.09, p = 1.2 × 10-10 ) and decreased risk of clinical vertebral fracture (OR = 0.82; FDR p = 7.4 × 10-4 ). Both SNPs are noncoding and were associated with increased mRNA expression levels in human bone biopsies: rs2468531 with SLC1A3 (ß = 0.28, FDR p = 0.01, involved in glutamate signaling and osteogenic response to mechanical loading) and rs12742784 with EPHB2 (ß = 0.12, FDR p = 1.7 × 10-3 , functions in bone-related ephrin signaling). Both genes are expressed in murine osteoblasts. This is the first study to link SLC1A3 and EPHB2 to clinically relevant vertebral osteoporosis phenotypes. These results may help elucidate vertebral bone biology and novel approaches to reducing vertebral fracture incidence. © 2016 American Society for Bone and Mineral Research.