Patients with cerebral small vessel disease (SVD) can present as isolated lacunar infarction or with diffuse white matter changes, with the imaging appearance of leukoaraiosis. Endothelial dysfunction, which can lead to breakdown of the blood-brain barrier, impaired cerebral autoregulation and prothrombotic changes, is believed to be important in mediating disease. Circulating levels of intercellular adhesion molecule 1 (ICAM1), thrombomodulin (TM), tissue factor (TF) and tissue factor pathway inhibitor (TFPI) are markers of endothelial activation and damage, and may provide insights into disease pathogenesis or differences between phenotypes. We therefore measured these markers in a prospective series of patients with lacunar stroke. One hundred and ten white Caucasian patients with previous lacunar stroke and 50 community control subjects were studied. Markers of endothelial function were measured on venous blood samples. Patients were classified on brain imaging into two groups: isolated lacunar infarction (n = 47) and ischaemic leukoaraiosis, defined as a clinical lacunar stroke and leukoaraiosis on brain imaging (n = 63). The number of lacunes and severity of leukoaraiosis were also scored on MRI. ICAM1, TM and TFPI were elevated in cerebral SVD subjects compared with controls (P

Ischaemic stroke can be caused by a number of monogenic disorders, and in such cases stroke is frequently part of a multisystem disorder. Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL), due to mutations in the NOTCH: 3 gene, is increasingly appreciated as a cause of familial subcortical stroke. The genetics and phenotypes of monogenic stroke are covered in this review. However, the majority of cases of ischaemic stroke are multifactorial in aetiology. Strong evidence from epidemiological and animal studies has implicated genetic influences in the pathogenesis of multifactorial ischaemic stroke, but the identification of individual causative mutations remains problematic; this is in part limited by the number of approaches currently available. In addition, genetic influences are likely to be polygenic, and ischaemic stroke itself consists of a number of different phenotypes which may each have different genetic profiles. Almost all human studies to date have employed a candidate gene approach. Associations with polymorphisms in a variety of candidate genes have been investigated, including haemostatic genes, genes controlling homocysteine metabolism, the angiotensin-converting enzyme gene, and the endothelial nitric oxide synthase gene. The results of these studies, and the advantages and limitations of the candidate gene approach, are presented. The recent biological revolution, spurred by the human genome project, promises the advent of novel technologies supported by bioinformatics resources that will transform the study of polygenic disorders such as stroke. Their potential application to polygenic ischaemic stroke is discussed.

Cerebral small vessel disease (SVD) causes focal lacunar infarction and more diffuse ischaemia, referred to as leukoaraiosis. Endothelial dysfunction has been proposed as a causal mechanism in the disease. Homocysteine is toxic to endothelium. We determined whether elevated homocysteine levels and the methylene tetrahydrofolate reductase (MTHFR) C677T polymorphism are risk factors for SVD as a whole, and for two different SVD subtypes: isolated lacunar infarction and ischaemic leukoaraiosis. We also determined whether any association was mediated by endothelial dysfunction, as assessed by circulating endothelial markers. One hundred and seventy-two Caucasian patients with SVD and 172 community controls of similar age and sex were studied. Serum homocysteine measurement and MTHFR genotyping was performed. Levels of intercellular adhesion molecule 1 (ICAM1) and thrombomodulin were measured in a subgroup. Mean homocysteine levels were higher in SVD than controls [14.55 micromol/l [95% confidence interval (CI) 13.78-15.35] versus 12.01 micromol/l (95% CI 11.42-12.64), P < 0.0005]. Homocysteine was a stronger risk factor in those with ischaemic leukoaraiosis [12.92 (95% CI 4.40-37.98), P < 0.0005) per micromol increase in log homocysteine concentration (P < 0.0005)] in comparison with isolated lacunar infarction [4.22 (95% CI 1.29-13.73), P = 0.02] after controlling for both conventional risk factors and age. The MTHFR 677T allele was a risk factor only in the ischaemic leukoaraiosis group [odds ratio (OR) 2.02 (95% CI 1.31-3.1), P = 0.001]. Inclusion of the endothelial markers ICAM1 and thrombomodulin in a logistic regression model resulted in the association between homocysteine and SVD no longer being significant. In conclusion, hyperhomocysteinaemia is an independent risk factor for SVD, particularly ischaemic leukoaraiosis, and this effect may be mediated via endothelial dysfunction. Homocysteine-lowering therapy may be particularly effective in this subgroup.

A family history of vascular disease is an independent risk factor for both large-vessel atherosclerosis and small-vessel disease, especially in cases presenting before age 65 years. The estimated sample sizes for case-control studies illustrate how candidate gene studies for ischemic stroke might be made more effective by focusing on these specific phenotypes, in which the genetic component of the disease appears to be strongest.

SVD has a different risk factor profile from the typical atherosclerotic profile found in LVD, with hypertension being important. There are differences in the risk factor profile between the SVD subtypes; the association of ILI with hypercholesterolaemia, diabetes and myocardial infarction may be consistent with a more atherosclerotic aetiology.

Background High blood pressure is common in acute stroke and is a predictor of poor outcome; however, large trials of lowering blood pressure have given variable results, and the management of high blood pressure in ultra-acute stroke remains unclear. We investigated whether transdermal glyceryl trinitrate (GTN; also known as nitroglycerin), a nitric oxide donor, might improve outcome when administered very early after stroke onset. Methods We did a multicentre, paramedic-delivered, ambulance-based, prospective, randomised, sham-controlled, blinded-endpoint, phase 3 trial in adults with presumed stroke within 4 h of onset, face-arm-speech-time score of 2 or 3, and systolic blood pressure 120 mm Hg or higher. Participants were randomly assigned (1:1) to receive transdermal GTN (5 mg once daily for 4 days; the GTN group) or a similar sham dressing (the sham group) in UKbased ambulances by paramedics, with treatment continued in hospital. Paramedics were unmasked to treatment, whereas participants were masked. The primary outcome was the 7-level modified Rankin Scale (mRS; a measure of functional outcome) at 90 days, assessed by central telephone follow-up with masking to treatment. Analysis was hierarchical, first in participants with a confirmed stroke or transient ischaemic attack (cohort 1), and then in all participants who were randomly assigned (intention to treat, cohort 2) according to the statistical analysis plan. This trial is registered with ISRCTN, number ISRCTN26986053.

Background and Purpose-Genetic influences are important in multifactorial cerebral small-vessel disease (SVD) and may act via endothelial dysfunction. Nitric oxide (NO) synthesized by endothelial nitric oxide synthase (eNOS) is a key mediator of endothelial function. We determined the role of 3 potentially functional eNOS polymorphisms (T-786C, intron 4ab, G894T) located toward the 5Ј flanking end of the gene as risk factors for SVD and different SVD subtypes: isolated lacunar infarction (nϭ137) and ischemic leukoaraiosis (nϭ160). Methods-Three hundred patients with SVD and 600 community controls were studied. Genotypes were determined through polymerase chain reaction with or without restriction fragment digestion. Nitrate (NO x ) levels were determined in a subgroup by use of a Griess method. Polymorphisms were tested individually and in combination with haplotype analysis. Results-The intron 4a variant was protective against SVD. This effect was confined to isolated lacunar infarction (odds ratio, 0.55; 95% confidence interval, 0.35 to 0.86; Pϭ0.01). Haplotypes encountered were significantly different in this subtype compared with controls (Pϭ0.001), with the -786C promoter/intron 4a combination particularly underrepresented. NO x levels were associated with the T-786C locus (Pϭ0.03) but only in the presence of the intron 4a allele (Pϭ0.07 for interaction). Conclusions-The intron 4ab insertion/deletion genotype was associated with isolated lacunar infarction. Haplotype and functional studies suggested that the protective effect of the 4a variant could be mediated through changes in eNOS promoter activity and increased NO levels. The specific association with isolated symptomatic lacunar infarction and not ischemic leukoaraiosis may reflect different etiopathogeneses of the 2 subtypes. Lack of NO could predispose to localized microatheroma in proximal arterioles rather than diffuse arteriosclerosis affecting distal perforating vessels.

SummaryBackgroundResults of small trials indicate that fluoxetine might improve functional outcomes after stroke. The FOCUS trial aimed to provide a precise estimate of these effects.MethodsFOCUS was a pragmatic, multicentre, parallel group, double-blind, randomised, placebo-controlled trial done at 103 hospitals in the UK. Patients were eligible if they were aged 18 years or older, had a clinical stroke diagnosis, were enrolled and randomly assigned between 2 days and 15 days after onset, and had focal neurological deficits. Patients were randomly allocated fluoxetine 20 mg or matching placebo orally once daily for 6 months via a web-based system by use of a minimisation algorithm. The primary outcome was functional status, measured with the modified Rankin Scale (mRS), at 6 months. Patients, carers, health-care staff, and the trial team were masked to treatment allocation. Functional status was assessed at 6 months and 12 months after randomisation. Patients were analysed according to their treatment allocation. This trial is registered with the ISRCTN registry, number ISRCTN83290762.FindingsBetween Sept 10, 2012, and March 31, 2017, 3127 patients were recruited. 1564 patients were allocated fluoxetine and 1563 allocated placebo. mRS data at 6 months were available for 1553 (99·3%) patients in each treatment group. The distribution across mRS categories at 6 months was similar in the fluoxetine and placebo groups (common odds ratio adjusted for minimisation variables 0·951 [95% CI 0·839–1·079]; p=0·439). Patients allocated fluoxetine were less likely than those allocated placebo to develop new depression by 6 months (210 [13·43%] patients vs 269 [17·21%]; difference 3·78% [95% CI 1·26–6·30]; p=0·0033), but they had more bone fractures (45 [2·88%] vs 23 [1·47%]; difference 1·41% [95% CI 0·38–2·43]; p=0·0070). There were no significant differences in any other event at 6 or 12 months.InterpretationFluoxetine 20 mg given daily for 6 months after acute stroke does not seem to improve functional outcomes. Although the treatment reduced the occurrence of depression, it increased the frequency of bone fractures. These results do not support the routine use of fluoxetine either for the prevention of post-stroke depression or to promote recovery of function.FundingUK Stroke Association and NIHR Health Technology Assessment Programme.