Dataset Information

Mitochondrial DNA haplogroups and risk of transient ischaemic attack and ischaemic stroke: a genetic association study.

ABSTRACT:

Background

Genetic factors have a role in the pathogenesis of ischaemic stroke, but the main genes involved have yet to be defined. Mitochondrial mechanisms have been implicated in the pathophysiology of acute stroke, but the role of mitochondrial DNA (mtDNA) has not been comprehensively studied. We investigated whether there is an association between mtDNA haplotypes and incidence of stroke.

Methods

The major European mtDNA haplogroups were identified in two independent subpopulations (n=950) from a study of occurrence of transient ischaemic attack (TIA) and ischaemic stroke and were compared with those of patients with acute coronary syndromes from the same populations (n=340) and with those of independent population controls (n=2939).

Findings

The presence of mtDNA sub-haplogroup K was significantly less frequent in patients with TIA or stroke than in controls in both subpopulations separately and in a pooled analysis (odds ratio 0.54, 95% CI 0.39-0.75, p<0.00001). This association remained highly significant after adjustment for multiple haplogroup comparisons. The association was significant for patients with TIA and stroke separately and was independent of known risk factors, but was not found for patients with acute coronary events. The mtDNA sub-haplogroup K was present in 8.7% of the total UK population controls and therefore confers a 4.0% (95% CI 2.2-5.7) reduction in population attributable risk of TIA and stroke.

Interpretation

Genetic variation of mtDNA sub-haplogroup K is an independent determinant of risk of cerebral, but not coronary, ischaemic vascular events. These findings implicate mitochondrial mechanisms in the aetiology of ischaemic stroke and provide a new means for the identification of individuals with a high susceptibility of developing ischaemic stroke.

SUBMITTER: Chinnery PF

PROVIDER: S-EPMC2855429 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundCerebral microbleeds are a neuroimaging biomarker of stroke risk. A crucial clinical question is whether cerebral microbleeds indicate patients with recent ischaemic stroke or transient ischaemic attack in whom the rate of future intracranial haemorrhage is likely to exceed that of recurrent ischaemic stroke when treated with antithrombotic drugs. We therefore aimed to establish whether a large burden of cerebral microbleeds or particular anatomical patterns of cerebral microbleeds can identify ischaemic stroke or transient ischaemic attack patients at higher absolute risk of intracranial haemorrhage than ischaemic stroke.MethodsWe did a pooled analysis of individual patient data from cohort studies in adults with recent ischaemic stroke or transient ischaemic attack. Cohorts were eligible for inclusion if they prospectively recruited adult participants with ischaemic stroke or transient ischaemic attack; included at least 50 participants; collected data on stroke events over at least 3 months follow-up; used an appropriate MRI sequence that is sensitive to magnetic susceptibility; and documented the number and anatomical distribution of cerebral microbleeds reliably using consensus criteria and validated scales. Our prespecified primary outcomes were a composite of any symptomatic intracranial haemorrhage or ischaemic stroke, symptomatic intracranial haemorrhage, and symptomatic ischaemic stroke. We registered this study with the PROSPERO international prospective register of systematic reviews, number CRD42016036602.FindingsBetween Jan 1, 1996, and Dec 1, 2018, we identified 344 studies. After exclusions for ineligibility or declined requests for inclusion, 20 322 patients from 38 cohorts (over 35 225 patient-years of follow-up; median 1·34 years [IQR 0·19-2·44]) were included in our analyses. The adjusted hazard ratio [aHR] comparing patients with cerebral microbleeds to those without was 1·35 (95% CI 1·20-1·50) for the composite outcome of intracranial haemorrhage and ischaemic stroke; 2·45 (1·82-3·29) for intracranial haemorrhage and 1·23 (1·08-1·40) for ischaemic stroke. The aHR increased with increasing cerebral microbleed burden for intracranial haemorrhage but this effect was less marked for ischaemic stroke (for five or more cerebral microbleeds, aHR 4·55 [95% CI 3·08-6·72] for intracranial haemorrhage vs 1·47 [1·19-1·80] for ischaemic stroke; for ten or more cerebral microbleeds, aHR 5·52 [3·36-9·05] vs 1·43 [1·07-1·91]; and for ≥20 cerebral microbleeds, aHR 8·61 [4·69-15·81] vs 1·86 [1·23-1·82]). However, irrespective of cerebral microbleed anatomical distribution or burden, the rate of ischaemic stroke exceeded that of intracranial haemorrhage (for ten or more cerebral microbleeds, 64 ischaemic strokes [95% CI 48-84] per 1000 patient-years vs 27 intracranial haemorrhages [17-41] per 1000 patient-years; and for ≥20 cerebral microbleeds, 73 ischaemic strokes [46-108] per 1000 patient-years vs 39 intracranial haemorrhages [21-67] per 1000 patient-years).InterpretationIn patients with recent ischaemic stroke or transient ischaemic attack, cerebral microbleeds are associated with a greater relative hazard (aHR) for subsequent intracranial haemorrhage than for ischaemic stroke, but the absolute risk of ischaemic stroke is higher than that of intracranial haemorrhage, regardless of cerebral microbleed presence, antomical distribution, or burden.FundingBritish Heart Foundation and UK Stroke Association.

Project description:BackgroundAn increasing body of evidence suggests that inflammation plays a key role in stroke, in particular stroke of atherosclerotic origin. Anti-inflammatory medications are a widely heterogeneous group of drugs that are used to suppress the innate inflammatory pathway and thus prevent persistent or recurrent inflammation. Anti-inflammatory agents have the potential to stabilise atherosclerotic plaques by impeding the inflammatory pathway. By targeting specific cytokines, the inflammatory pathway may be interrupted at various stages.ObjectivesTo assess the benefits and harms of anti-inflammatory medications plus standard care versus standard care with or without placebo for prevention of vascular events (stroke, myocardial infarction (MI), non-fatal cardiac arrest, unstable angina requiring revascularisation, vascular death) and all-cause mortality in people with a prior history of ischaemic stroke or transient ischaemic attack (TIA).Search methodsWe searched the Cochrane Central Register of Controlled Trials (CENTRAL; last searched 29 May 2019); MEDLINE (1948 to 29 May 2019); Embase (1980 to 29 May 2019); the Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1982 to 29 May 2019); and Scopus (1995 to 29 May 2019). In an effort to identify additional published, unpublished, and ongoing trials, we searched several grey literature sources (last searched 30 May 2019). We incorporated all identified studies into the results section. We applied no restrictions with respect to language, date of publication, or study setting.Selection criteriaWe considered randomised controlled trials (RCTs) and cluster-randomised controlled trials that evaluated anti-inflammatory medications for prevention of major cardiovascular events following ischaemic stroke or TIA.Data collection and analysisTwo review authors independently assessed for inclusion titles and abstracts of studies identified by the search. Two review authors independently reviewed full-text articles for inclusion in this review. We planned to assess risk of bias and to apply the GRADE method.Main resultsWe identified no studies that met the inclusion criteria.Authors' conclusionsThere is currently a paucity of evidence on the use of anti-inflammatory medications for prevention of major cardiovascular events following ischaemic stroke or TIA. RCTs are needed to assess whether use of anti-inflammatory medications in this setting is beneficial.

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Project description:IntroductionLiterature on prevalence of symptomatic internal carotid artery stenosis is scarce and heterogeneous. Prevalence may have decreased in recent years due to improved management of cardiovascular risk factors. We aim to estimate current prevalence and identify risk factors of ipsilateral internal carotid artery stenosis in patients with recent hemispheric transient ischaemic attack or ischaemic stroke in the Netherlands.Patients and methodsWe included consecutive adult patients admitted to two large hospitals in the Netherlands in 2014 who suffered from amaurosis fugax, retinal ischaemia, transient ischaemic attack or ischaemic stroke in the vessel territory of the internal carotid artery. Primary outcome was presence of ipsilateral internal carotid artery stenosis (degree subdivided following NASCET criteria), as assessed with duplex ultrasonography, computed tomography angiography and/or magnetic resonance angiography. We used univariable and multivariable logistic regression to identify risk factors for the presence of a 50-100% internal carotid artery stenosis.ResultsWe analysed 883 consecutive patients with recent transient ischaemic attack or ischaemic stroke. Of these, 110 (12.5%) had 50-99% ipsilateral internal carotid artery stenosis. Subgroup analyses showed higher prevalence of any degree of internal carotid artery stenosis for male sex and White patients. In adjusted analyses, higher age (odds ratio 1.4/10 years; 95% confidence interval 1.16-1.63), male sex (odds ratio 2.8; 95% confidence interval 1.83-4.19), retinal ischaemia (odds ratio 2.5; 95% confidence interval 1.32-4.76) and current smoking (odds ratio 1.8; 95% confidence interval 1.09-2.79) were statistically significant risk factors for 50-100% internal carotid artery stenosis.ConclusionThe prevalence of internal carotid artery stenosis seems to be lower in patients with recent transient ischaemic attack or ischaemic stroke than stated in previous studies. We found that higher age, male sex, White ethnicity, retinal ischaemia and current smoking were important risk factors for symptomatic internal carotid artery stenosis.