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Introduction: The role of serum uric acid (UA) levels in the functional recovery of ischemic stroke remains uncertain. To evaluate whether UA could predict clinical outcomes in patients with ischemic stroke., Patients and Methods: A three-stage study design was employed, combining a large-scale prospective cohort study, a meta-analysis and a Mendelian randomization (MR) analysis. Firstly, we conducted a cohort study using data from the Nanjing Stroke Registry Program (NSRP) to assess the association between UA levels and 3-month functional outcomes in ischemic stroke patients. Secondly, the meta-analysis was conducted to integrate currently available cohort evidence. Lastly, MR analysis was utilized to explore whether genetically determined UA had a causal link to the functional outcomes of ischemic stroke using summary data from the CKDGen and GISCOME datasets., Results: In the first stage, the cohort study included 5631 patients and found no significant association between UA levels and functional outcomes at 3 months after ischemic stroke. In the second stage, the meta-analysis, including 10 studies with 14,657 patients, also showed no significant association between UA levels and stroke prognosis. Finally, in the third stage, MR analysis using data from 6165 patients in the GISCOME study revealed no evidence of a causal relationship between genetically determined UA and stroke functional outcomes., Discussion and Conclusion: Our comprehensive triangulation approach found no significant association between UA levels and functional outcomes at 3 months after ischemic stroke., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Frailty appears to be associated with unfavorable prognosis after stroke in observational studies, but the causality remains largely unknown., Aims: The aim of this study is to investigate the potential causal effect of frailty on functional outcome at 3 months after ischemic stroke using the Mendelian randomization (MR) framework., Methods: Genetic instruments for frailty index were identified in a genome-wide association study meta-analysis including 175,226 individuals of European descent. Corresponding genetic association estimates for functional outcome after ischemic stroke at 90 days were taken from the Genetic of Ischemic Stroke Functional Outcome (GISCOME) network of 6021 patients. We performed inverse-variance weighted MR as the main analyses, followed by several alternate methods and sensitivity analyses., Results: In univariable MR, we found evidence that genetically predicted higher frailty index (odds ratio (OR) = 5.12; 95% confidence interval (CI) = 1.31-20.09; p  = 0.019) was associated with worse functional outcome (modified Rankin Scale score ⩾3) after ischemic stroke. In further multivariable MR adjusting for potential confounding traits including body mass index, C-reactive protein, inflammatory bowel disease, and smoking initiation, the overall patterns between genetic liability to frailty and poor functional outcome status remained. Sensitivity analyses with complementary methods and with model unadjusted for baseline stroke severity (OR = 4.19; 95% CI = 1.26-13.90; p  = 0.019) yielded broadly concordant results., Conclusions: The present MR study suggested a possible causal effect of frailty on poor functional outcome after ischemic stroke. Frailty might represent a potential target for intervention to improve recovery after ischemic stroke., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Observational studies have reported that coffee consumption was associated with Alzheimer's disease (AD) and stroke risk. However, the results are inconclusive., Objective: We aimed to evaluate whether genetically predicted coffee consumption is associated with AD and stroke using Mendelian randomization (MR) design., Methods: Summary-level data for AD (n = 54,162), ischemic stroke (n = 440,328), and intracerebral hemorrhage (ICH, n = 3,026) were adopted from publicly available databases. Summary-level data for coffee consumption were obtained from two genome-wide association studies, comprising up to 375,833 subjects., Results: Genetically predicted coffee consumption (cups/day) was associated with an increased risk of AD (OR = 1.26, 95%CI = 1.05-1.51). Moreover, genetically predicted 50%increase of coffee consumption was associated with an increased risk of ICH (OR: 2.27, 95%CI: 1.08-4.78) but a decreased risk of small vessel stroke (OR: 0.71, 95%CI: 0.51-0.996). Estimate for AD and ICH in FinnGen consortium is directionally consistent. Combined analysis of different databases further confirmed that genetically predicted coffee consumption was associated with an increased risk of AD and ICH. In the multivariable MR analysis, genetically predicted coffee consumption retained a stable effect with AD and ICH when adjusting for smoking (p < 0.05), while the association with AD attenuated when adjusting for alcohol use., Conclusion: Our results indicate that genetically predicted coffee consumption may be associated with an increased risk of AD and ICH. The underlying biological mechanisms warrant further study.

Background and Purpose: Although observational studies have reported a positive association between depression and ischemic stroke, causality remains inconclusive. We aimed to assess the causal relationship of major depressive disorder (MDD) with ischemic stroke, especially with the small vessel stroke (SVS) subtype., Methods: We used 72 independent single-nucleotide polymorphisms associated with MDD in a genome-wide association study (GWAS) from the Psychiatric Genetics Consortium as instrumental variables. The corresponding data for ischemic stroke and its subtypes of European ancestry were available from the MEGASTROKE consortium of 34,217 ischemic stroke cases and 406,111 controls. Primary Mendelian randomization estimates were calculated with inverse-variance weighted method, and several alternate methods and multiple sensitivity analyses were also performed., Results: We found that genetic predisposition to higher risk of MDD was associated with higher risk of SVS, with an odds ratio of 1.33 (95% confidence interval, 1.08-1.65; p = 0.009) per log-odds increment in MDD risk, but not with large artery stroke (OR, 1.08; 95% CI 0.83-1.41; p = 0.559), cardioembolic stroke (OR, 0.98; 95% CI 0.80-1.20; p = 0.833), or all ischemic stroke (OR, 1.03; 95% CI 0.92-1.15; p = 0.633). The association of MDD with SVS was overall robust to sensitivity analyses., Conclusions: We provided evidence for a possible causal effect of MDD on increased risk of SVS. Future researches are required to investigate whether rational intervention on depression may help to reduce societal burden of SVS.

Elevated C-reactive protein (CRP) levels increase the risk of poor functional disability in patients with ischemic stroke (IS). This study aimed to investigate the association between CRP gene polymorphisms and 3-month functional disability of large artery atherosclerotic (LAA) stroke in Han Chinese. Patients with first-ever LAA IS were prospectively enrolled in Nanjing Stroke Registry Program between August 2013 and October 2015. Five single-nucleotide polymorphisms (SNPs) (rs876537, rs2794520, rs3093059, rs7553007 and rs11265260) in CRP gene related to CRP levels in Asian by genome-wide association study were genotyped. The functional outcome at 3 months after the index stroke was assessed by the modified Rankin scale. Associations between genotypes and functional outcome of LAA IS were analyzed with logistic regression model. A total of 690 eligible patients (507 males) were evaluated. SNPs rs11265260 (multivariate-adjusted, p = 0.022), rs2794520 (multivariate-adjusted, p = 0.036) and rs3093059 (multivariate-adjusted, p = 0.027) were significantly associated with elevated CRP in acute IS. Two SNPs, rs3093059 (dominant model: adjusted OR 2.49; 95% CI 1.55-4.00; recessive model: adjusted OR 3.67; 95% CI 1.22-11.03) and rs11265260 (dominant model: adjusted OR 2.51; 95% CI 1.56-4.02; recessive model: adjusted OR 4.70; 95% CI 1.63-13.56) independently predicted 3-month poor outcome of first-ever LAA IS, after adjusting for covariates. In addition, haplotype analysis indicated that haplotype GCTGC (adjusted OR 1.76; 95% CI 1.05-2.95; p = 0.031) increased the poor outcome risk. SNPs rs3093059 and rs11265260 in CRP gene may influence the 3-month functional outcome of first-ever LAA IS in Han Chinese.

Background: The variant rs9943582 of APLNR (apelin receptor) was identified by a large-scale study to be associated with an increased risk of ischemic stroke in a Japanese population. We conducted this study to investigate the association between the variant and age of onset and clinical outcomes of ischemic stroke in a Chinese population., Methods: Improved multiple ligase detection reaction was used to genotype the variant. We compared the mean age at ischemic stroke onset with one-way ANOVA. The Kaplan-Meier method, log-rank test, and Cox proportional hazards regression models were performed to analyze the association between the variant and clinical outcomes (recurrence and death)., Results: A total of 916 ischemic stroke patients were recruited for the study. For age at ischemic stroke onset, no significant association was identified with the variant in any genetic model. In addition, the variant was not strongly associated with recurrence and death risk of ischemic stroke, as shown by the results., Conclusions: The findings indicated that the variant rs9943582 was not associated with age at onset and clinical outcomes of ischemic stroke. However, evidence from well-designed studies with larger and in different ethnic populations are warranted to further explore the effects of APLNR on the ischemic stroke onset and clinical outcomes., (Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.)

Aim: CDKN2A/2B near chromosome 9p21 has been proposed as a potential genetic etiology for both atherosclerosis and arterial calcification. DNA methylation, which can change the expression of CDKN2A/2B, may be an underlying mechanism for this association. This study aimed to evaluate whether CDKN2A/2B methylation is related to aortic arch calcification (AAC) in patients with ischemic stroke., Methods: DNA methylation levels of CDKN2A/2B was measured using venous blood samples in 322 patients with ischemic stroke. A total of 36 CpG sites around promoter regions of CDKN2A/2B were examined. AAC was quantified with Agatston score based on results of computed tomography angiography., Results: There were 248 (77.0%) patients with and 74 (23.0%) patients without evident AAC. Compared with patients without AAC, patients with AAC had higher methylation levels of CDKN2B (5.72 vs 4.94, P＜0.001). Using a generalized linear model, positive correlation between methylation levels and log-transformed calcification scores was detected at CDKN2B (β=0.275±0.116, P= 0.018)., Conclusion: Patients with higher levels of DNA methylation of CDKN2B may bear increased risk for AAC. Further studies to reveal the underlying mechanisms of this association are warranted for establishing a cause-effect relationship.

Purpose: Prostaglandin-Endoperoxide Synthase 1 (PTGS1) and smoking may play important roles in aspirin nonresponsiveness, but the effect of their interaction on stroke outcomes remains largely unknown. We examined the effects of PTGS1 polymorphisms, smoking status, and their interaction on functional outcomes in a cohort of Chinese Han patients with stroke during aspirin therapy., Methods: A total of 617 ischemic stroke patients taking aspirin were enrolled. Three single nucleotide polymorphisms (SNPs) rs1330344, rs3842788, and rs5788 in PTGS1 were determined for genotyping. Poor functional outcomes were defined as a modified Rankin Scale (mRS) of 3-6 at 90-day follow-up. The influence of PTGS1 gene-smoking interaction on functional outcomes was examined., Results: Poor functional outcomes occurred in 145 (23.5%) patients. When adjusting multiple factors by logistic regression, CC genotype of rs1330344 was associated with poor functional outcomes (risk ratio [RR]=1.73; 95% confidence interval [CI]: 1.17-2.37). A similar connection was found in the CGC haplotype (RR=1.40; 95% CI: 1.08-1.77). Furthermore, we found a significant interaction between rs1330344 and smoking status (P interaction =0.018); the interaction effect between the PTGS1 haplotype and smoking also showed statistical significance (P interaction =0.040)., Conclusions: In Chinese Han stroke patients with aspirin therapy, the adverse effect of PTGS1 polymorphisms on functional outcomes may be modulated by the smoking status. PTGS1 gene-smoking interaction might in part reflect the heterogeneity in the prognosis of patients treated with aspirin., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Recently, a single nucleotide polymorphism (SNP) rs505922 in ABO gene was related to large artery atherosclerotic (LAA) stroke in Caucasian populations by genome-wide association study (GWAS). This study aimed to determine whether ABO gene polymorphisms are associated with LAA stroke in Chinese Han population. A case-control study was designed, and 644 patients with LAA stroke and 642 healthy controls were enrolled. Ten tagging SNPs (tSNPs) located in ABO gene were genotyped. Associations between genotypes and LAA stroke were analyzed with logistic regression model after adjustment of potential confounders. Although rs505922 was not associated with LAA stroke (TT genotype, adjusted OR = 1.32; 95 % CI, 0.94 to 1.87), two novel SNPs, rs8176668 (AT genotype, adjusted OR = 0.71; 95 % CI, 0.55 to 0.92) and rs2073824 (AA genotype, adjusted OR = 0.72; 95 % CI, 0.57 to 0.92), were associated with LAA stroke. Haplotype analysis indicated that haplotype TC (adjusted OR = 0.72; 95 % CI, 0.54 to 0.95; P = 0.018) in block 1 and haplotype ACA in block 2 (OR = 0.73; 95 % CI, 0.58 to 0.91; P = 0.005) were associated with LAA stroke. Multifactor dimensionality reduction (MDR) analysis in the single-locus model indicated that rs2073824 was the most important attributor for predicting risk of LAA stroke. No significant SNP-SNP interactions among the tested SNPs were detected. The results indicated that the genetic variants in ABO gene may influence the risk of LAA stroke in Chinese Han population.

Recent genome-wide association study associated rs556621 on chromosome 6p21.1 with the risk of large artery atherosclerotic (LAA) stroke in Caucasians. However, subsequent replicate studies showed conflict results in different ethnicities. This study aimed to evaluate whether rs556621 was associated with LAA stroke in Chinese Han population. In this case-control study, 659 patients with LAA stroke and 650 healthy controls were enrolled. Associations between rs556621 genotypes and LAA stroke were analyzed with logistic regression model. Rs556621 variants were associated with increased risks of LAA stroke (codominant model: OR 1.42; 95 % CI 1.01-1.99; P = 0.010; recessive model: OR 1.40; 95 % CI 1.05-1.86; P = 0.003). When subjects were stratified by sex, TT genotype of SNP rs556621 was associated with an increased risk of LAA stroke in female when tested with recessive model (OR 2.36; 95 % CI 1.28-4.36, P = 0.006). In male subjects, however, no significant association was detected. Smoking status, sex did not significantly influence the relationship between genotypes of rs556621 and risk of LAA stroke (P interaction  = 0.140, P interaction  = 0.076). Rs556621 may play an important role in the development of LAA stroke in female Chinese of Han ethnicity. Larger studies with subjects of different ethnicities are warranted to confirm these findings.

Background: Cyclin-dependent kinase inhibitor 2A/2B (CDKN2A/2B) near chromosome 9p21 have been associated with both atherosclerosis and artery calcification, but the underlying mechanisms remained largely unknown. Considering that CDKN2A/2B is a frequently reported site for DNA methylation, this study aimed to evaluate whether carotid artery calcification (CarAC) is related to methylation levels of CDKN2A/2B in patients with ischemic stroke., Methods: DNA methylation levels of CDKN2A/2B were measured in 322 ischemic stroke patients using peripheral blood leukocytes. Methylation levels of 36 CpG sites around promoter regions of CDKN2A/2B were examined with BiSulfite Amplicon Sequencing. CarAC was quantified with Agatston score based on results of computed tomography angiography. Generalized liner model was performed to explore the association between methylation levels and CarAC., Results: Of the 322 analyzed patients, 187 (58.1%) were classified as with and 135 (41.9%) without evident CarAC. The average methylation levels of CDKN2B were higher in patents with CarAC than those without (5.7 vs 5.4, p = 0.001). After adjustment for potential confounders, methylation levels of CDKN2B were positively correlated with cube root transformed calcification scores (β = 0.591 ± 0.172, p = 0.001) in generalized liner model. A positive correlation was also detected between average methylation levels of CDKN2B and cube root transformed calcium volumes (β = 0.533 ± 0.160, p = 0.001)., Conclusions: DNA methylation of CDKN2B may play a potential role in artery calcification.

Background: Despite clopidogrel has been widely applied to patients with ischemic stroke combined with aspirin, decreased metabolic activation of clopidogrel still occurs because of genetic variations in CYP2C19., Methods: Three hundred twenty-one patients completed a genetic test for CYP2C19 loss of function (LOF) alleles in hospital. Cox regression models were used to assess the relationship between CYP2C19 genotypes with the primary endpoint, which was a composite of nonfatal ischemic stroke, myocardial infarction, or vascular death. Functional outcome was measured by the modified Rankin Scale (mRS) at 3months, 6months and 12months intervals. Binary logistic regression was used to analyze the correlation between poor functional outcome and CYP2C19 LOF alleles., Results: The CYP2C19 LOF alleles were independently associated with the primary endpoint. There was no significant association between poor functional outcome and CYP2C19 LOF allele (*2 and *3) in overall patients. After the participants were stratified by stent treatment into two groups, the polymorphisms of CYP2C19 had significant impact on poor prognosis at 3months and 6months but not at 12months in patients without stent. No correlation was found in patients with stent., Conclusions: The CYP2C19 LOF alleles may increase the recurrent risk of ischemic events. The polymorphisms of CYP2C19 may be predictors of poor functional outcome of patients without stent, and the effect may be weakened by time., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Background and purpose: Considerable studies have reported inconsistent relationships between ischemic stroke and a large number of factors. These uncertainties may reflect the susceptibility to confounding in observational studies. We aimed to assess genetic correlations and causal relationships between ischemic stroke and diverse phenotypes. Methods: Summary-level data for ischemic stroke (34,217 cases and 406,111 controls) from the MEGASTROKE consortium were used as the outcome. Exposures were derived from two GWAS statistics curated databases. We explored the genetic correlations and causalities between hundreds of traits and ischemic stroke, using linkage disequilibrium score regression and Mendelian randomization (MR), respectively. Multiple sensitivity analyses were also performed. Results: Genetic correlation analyses reflected genetic overlaps between ischemic stroke and physical activity, cardiometabolic factors, smoking, and lung function. Applying MR, we found suggestive evidence that genetic predisposition to higher concentration of low-density lipoprotein particles (LDL.P) and cholesterol carried in different sizes of LDL.P (LDL.C) were associated with higher risk of ischemic stroke, particular large artery stroke. The strongest effect was observed for small LDL.P in large artery stroke (OR 1.31, 95% CI 1.09–1.56, p = 0.003). The results were overall robust for sensitivity analyses. We further observed significant positive associations of genetically predicted LDL.P and LDL.C with coronary artery disease and myocardial infarction. Conclusions: Shared genetic overlaps might exist between ischemic stroke and physical activity, cardiometabolic factors, smoking, and lung function. We provided suggestive evidence for a potential causal role of LDL.P and LDL.C in ischemic stroke, particularly in large artery stroke. Future researches are required to confirm these findings. [ABSTRACT FROM AUTHOR]