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The antiviral enzyme cholesterol 25-hydroxylase (CH25H) and its metabolite 25-hydroxycholesterol (25HC), which modulates cholesterol metabolism during infection, have been associated with vascular pathology. Viral infections have been linked to intracerebral haemorrhage (ICH) risk, but the molecular mechanisms leading to ICH via antiviral responses remain unknown. We hypothesised that the CH25H/25HC pathway impacts neuroendothelial integrity in the context of infection-associated ICH. Using a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein-induced zebrafish ICH model and foetal human SARS-CoV-2-associated cortical tissue containing microbleeds, we identified upregulation of CH25H in infection-associated cerebral haemorrhage. Using zebrafish models and human brain endothelial cells, we asked whether 25HC promotes neurovascular dysfunction by modulating cholesterol metabolism. We found that 25HC and pharmacological inhibition of cholesterol synthesis had an additive effect to exacerbate brain bleeding in zebrafish and in vitro neuroendothelial dysfunction. 25HC-induced dysfunction was also rescued by cholesterol supplementation in vitro. These results demonstrate that 25HC can dysregulate brain endothelial function by remodelling cholesterol metabolism. We propose that CH25H/25HC plays an important role in the pathophysiology of brain vessel dysfunction associated with infection and cholesterol dysregulation in the context of ICH.

Aicardi-Goutières syndrome (AGS1-9) is a genetically determined encephalopathy that falls under the type I interferonopathy disease class, characterized by excessive type I interferon (IFN-I) activity, coupled with upregulation of IFN-stimulated genes (ISGs), which can be explained by the vital role these proteins play in self-non-self-discrimination. To date, few mouse models fully replicate the vast clinical phenotypes observed in AGS patients. Therefore, we investigated the use of zebrafish as an alternative species for generating a clinically relevant model of AGS. Using CRISPR-cas9 technology, we generated a stable mutant zebrafish line recapitulating AGS5, which arises from recessive mutations in SAMHD1 . The resulting homozygous mutant zebrafish larvae possess a number of neurological phenotypes, exemplified by variable, but increased expression of several ISGs in the head region, a significant increase in brain cell death, microcephaly and locomotion deficits. A link between IFN-I signaling and cholesterol biosynthesis has been highlighted by others, but not previously implicated in the type I interferonopathies. Through assessment of neurovascular integrity and qPCR analysis we identified a significant dysregulation of cholesterol biosynthesis in the zebrafish model. Furthermore, dysregulation of cholesterol biosynthesis gene expression was also observed through RNA sequencing analysis of AGS patient whole blood. From this novel finding, we hypothesize that cholesterol dysregulation may play a role in AGS disease pathophysiology. Further experimentation will lend critical insight into the molecular pathophysiology of AGS and the potential links involving aberrant type I IFN signaling and cholesterol dysregulation.

The antiviral enzyme cholesterol 25-hydroxylase (CH25H) and its metabolite 25-hydroxycholesterol (25HC), which modulates cholesterol metabolism during infection, have been previously associated with vascular pathology. Viral infections have been linked to risk of intracerebral haemorrhage (ICH) but the molecular mechanisms leading to brain vessel rupture via antiviral responses remain unknown. We hypothesised that the CH25H/25HC pathway may impact neuroendothelial integrity in the context of infection-associated ICH. Here, using a SARS-CoV-2-spike-induced zebrafish ICH model and foetal human SARS-CoV-2-associated cortical tissue containing microbleeds, we identified an upregulation of CH25H in infection-associated cerebral haemorrhage. Using zebrafish ICH models and human brain endothelial cells, we asked whether 25HC may promote neurovascular dysfunction by modulating cholesterol metabolism. We found that 25HC and pharmacological inhibition of HMGCR by atorvastatin interacted to exacerbate brain bleeding in zebrafish larvae and in vitro brain endothelial dysfunction. In vitro 25HC-induced dysfunction was also rescued by cholesterol supplementation. These results demonstrate that the antiviral factor 25HC can dysregulate brain endothelial function by remodelling cholesterol metabolism. We propose that the CH25H/25HC pathway represents an important component in the pathophysiology of brain vessel dysfunction associated with infection and cholesterol dysregulation in the context of ICH. The antiviral metabolite 25-hydroxycholesterol dysregulates brain endothelial function by remodelling cholesterol metabolism, thereby providing a mechanistic link between viral infection and brain endothelial dysfunction in conditions such as intracerebral haemorrhage.

Extracranial carotid and vertebral artery dissection is an important cause of stroke, especially in young people. In some observational studies it has been associated with a high risk of recurrent stroke. Both antiplatelet drugs and anticoagulant drugs are used to reduce risk of stroke but whether one treatment strategy is more effective than the other is unknown. We compared their efficacy in the Cervical Artery Dissection in Stroke Study (CADISS), with the additional aim of establishing the true risk of recurrent stroke. We did this randomised trial at hospitals with specialised stroke or neurology services (39 in the UK and seven in Australia). We included patients with extracranial carotid and vertebral dissection with onset of symptoms within the past 7 days. Patients were randomly assigned (1:1) by an automated telephone randomisation service to receive antiplatelet drugs or anticoagulant drugs (specific treatment decided by the local clinician) for 3 months. Patients and clinicians were not masked to allocation, but investigators assessing endpoints were. The primary endpoint was ipsilateral stroke or death in the intention-to-treat population. The trial was registered with EUDract (2006-002827-18) and ISRN (CTN44555237). We enrolled 250 participants (118 carotid, 132 vertebral). Mean time to randomisation was 3·65 days (SD 1·91). The major presenting symptoms were stroke or transient ischaemic attack (n=224) and local symptoms (headache, neck pain, or Horner's syndrome; n=26). 126 participants were assigned to antiplatelet treatment versus 124 to anticoagulant treatment. Overall, four (2%) of 250 patients had stroke recurrence (all ipsilateral). Stroke or death occurred in three (2%) of 126 patients versus one (1%) of 124 (odds ratio [OR] 0·335, 95% CI 0·006–4·233; p=0·63). There were no deaths, but one major bleeding (subarachnoid haemorrhage) in the anticoagulant group. Central review of imaging failed to confirm dissection in 52 patients. Preplanned per-protocol analysis excluding these patients showed stroke or death in three (3%) of 101 patients in the antiplatelet group versus one (1%) of 96 patients in the anticoagulant group (OR 0·346, 95% CI 0·006–4·390; p=0·66). We found no difference in efficacy of antiplatelet and anticoagulant drugs at preventing stroke and death in patients with symptomatic carotid and vertebral artery dissection but stroke was rare in both groups, and much rarer than reported in some observational studies. Diagnosis of dissection was not confirmed after review in many cases, suggesting that radiographic criteria are not always correctly applied in routine clinical practice. Stroke Association.

Background Recruitment to randomised prevention trials is challenging, not least for intracerebral haemorrhage (ICH) associated with antithrombotic drug use. We investigated reasons for not recruiting apparently eligible patients at hospital sites that keep screening logs in the ongoing REstart or STop Antithrombotics Randomised Trial (RESTART), which seeks to determine whether to start antiplatelet drugs after ICH. Method By the end of May 2015, 158 participants had been recruited at 108 active sites in RESTART. The trial coordinating centre invited all sites that kept screening logs to submit screening log data, followed by one reminder. We checked the integrity of data, focused on the completeness of data about potentially eligible patients and categorised the reasons they were not randomised. Results Of 108 active sites, 39 (36%) provided usable screening log data over a median of ten (interquartile range = 5–13) months of recruitment per site. During this time, sites screened 633 potentially eligible patients and randomised 53 (8%) of them. The main reasons why 580 patients were not randomised were: 43 (7%) patients started anticoagulation, 51 (9%) patients declined, 148 (26%) patients’ stroke physicians were not uncertain about using antiplatelet drugs, 162 (28%) patients were too unwell and 176 (30%) patients were not randomised due to other reasons. Conclusion RESTART recruited ~8% of eligible patients. If more physicians were uncertain about the therapeutic dilemma that RESTART is addressing, RESTART could have recruited up to four times as many participants. The trial coordinating centre continues to engage with physicians about their uncertainty. Trial registration EU Clinical Trials, EudraCT 2012-003190-26 . Registered on 3 July 2012.

Background This review focuses on neurology research which uses routinely collected data. The number of such studies is growing alongside the expansion of data collection. We aim to gain a broad picture of the scope of how routine healthcare data have been utilised. Methods This study follows a systematic mapping review approach which does not make a judgement on the quality of the papers included in the review, thereby enabling a complete overview of the field. Results Of 4481 publications retrieved, 386 met the eligibility criteria for this study. These publications covered a wide range of conditions, but the majority were based on one or only a small number of neurological conditions. In particular, publications concerned with three discrete areas of neurological practice - multiple sclerosis (MS), epilepsy/seizure and Parkinson’s disease - accounted for 60% of the total. MS was the focus of the highest proportion of eligible studies (35%), yet in the recent Global Burden of Neurological Disease study it ranks only 14th out of 15 neurological disorders for DALY rates. In contrast, migraine is the neurological disorder with the highest ranking of DALYs globally (after stroke) and yet it was represented by only 4% of eligible studies. Conclusion This review shows that there is a disproportionately large body of literature pertaining to relatively rare disorders, and a correspondingly small body of literature describing more common conditions. Therefore, there is potential for future research to redress this balance.