Search

Cerebral microbleeds (CMBs) detected on magnetic resonance imaging are common in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). The neuropathologic correlates of CMBs are unclear. In this study, we characterized findings relevant to CMBs in autopsy brain tissue of 8 patients with genetically confirmed CADASIL and 10 controls within the age range of the CADASIL patients by assessing the distribution and extent of hemosiderin/iron deposits including perivascular hemosiderin leakage (PVH), capillary hemosiderin deposits, and parenchymal iron deposits (PID) in the frontal cortex and white matter, basal ganglia and cerebellum. We also characterized infarcts, vessel wall thickening, and severity of vascular smooth muscle cell degeneration. CADASIL subjects had a significant increase in hemosiderin/iron deposits compared with controls. This increase was principally seen with PID. Hemosiderin/iron deposits were seen in the majority of CADASIL subjects in all brain areas. PVH was most pronounced in the frontal white matter and basal ganglia around small to medium sized arterioles, with no predilection for the vicinity of vessels with severe vascular changes or infarcts. CADASIL subjects have increased brain hemosiderin/iron deposits but these do not occur in a periarteriolar distribution. Pathogenesis of these lesions remains uncertain.

Poststroke dementia (PSD) is associated with pathology in frontal brain regions, in particular dorsolateral prefrontal cortex (DLPFC) neurons and white matter, remote from the infarct. We hypothesised that PSD results from progressive DLPFC neuronal damage, associated with frontal white matter gliovascular unit (GVU) alterations. We investigated the transcriptomic profile of the neurons and white matter GVU cells previously implicated in pathology. Laser-capture microdissected neurons, astrocytes and endothelial cells were obtained from the Cognitive Function After Stroke cohort of control, PSD and poststroke non-dementia (PSND) human subjects. Gene expression was assessed using microarrays and pathway analysis to compare changes in PSD with controls and PSND. Neuronal findings were validated using NanoString technology and compared with those in the bilateral common carotid artery stenosis (BCAS) mouse model. Comparing changes in PSD compared to controls with changes in PSND compared to controls identified transcriptomic changes associated specifically with dementia. DLPFC neurons showed defects in energy production (tricarboxylic acid (TCA) cycle, adenosine triphosphate (ATP) binding and mitochondria), signalling and communication (MAPK signalling, Toll-like receptor signalling, endocytosis). Similar changes were identified in neurons isolated from BCAS mice. Neuronal findings accompanied by altered astrocyte communication and endothelium immune changes in the frontal white matter, suggesting GVU dysfunction. We propose a pathogenic model in PSD whereby neuronal changes are associated with frontal white matter GVU dysfunction leading to astrocyte failure in supporting neuronal circuits resulting in delayed cognitive decline associated with PSD. Therefore, targeting these processes could potentially ameliorate the dementia seen in PSD.

Alzheimer disease (AD) is the most common cause of dementia. Biological definitions of AD are limited to the cerebral burden of amyloid β plaques, neurofibrillary pathology, and neurodegeneration. However, current evidence suggests that various features of small vessel disease (SVD) are part of and covertly modify both sporadic and familial AD. Neuroimaging studies suggest that white matter hyperintensities explained by vascular mechanisms occurs frequently in the AD spectrum. Recent advances have further emphasized that frontal periventricular and posterior white matter hyperintensities are associated with cerebral amyloid angiopathy in familial AD. Although whether SVD markers precede the classically recognized biomarkers of disease is debatable, post-mortem studies show that SVD pathology incorporating small cortical and subcortical infarcts, microinfarcts, microbleeds, perivascular spacing, and white matter attenuation is commonly found in sporadic as well as in mutation carriers with confirmed familial AD. Age-related cerebral vessel pathologies such as arteriolosclerosis and cerebral amyloid angiopathy modify progression or worsen risk by shifting the threshold for cognitive impairment and AD dementia. The incorporation of SVD as a biomarker is warranted in the biological definition of AD. Therapeutic interventions directly reducing the burden of brain amyloid β have had no major impact on the disease or delaying cognitive deterioration, but lowering the risk of vascular disease seems the only rational approach to tackle both early- and late-onset AD dementia.

We have provided an overview on the profound impact of COVID‐19 upon older people with Alzheimer's disease and other dementias and the challenges encountered in our management of dementia in different health‐care settings, including hospital, out‐patient, care homes, and the community during the COVID‐19 pandemic. We have also proposed a conceptual framework and practical suggestions for health‐care providers in tackling these challenges, which can also apply to the care of older people in general, with or without other neurological diseases, such as stroke or parkinsonism. We believe this review will provide strategic directions and set standards for health‐care leaders in dementia, including governmental bodies around the world in coordinating emergency response plans for protecting and caring for older people with dementia amid the COIVD‐19 outbreak, which is likely to continue at varying severity in different regions around the world in the medium term.

Stroke is a leading cause of disability, dementia and death worldwide. Approximately 70% of deaths from stroke and 87% of stroke-related disability occur in low-income and middle-income countries. At the turn of the century, the most common diseases in Africa were communicable diseases, whereas non-communicable diseases, including stroke, were considered rare, particularly in sub-Saharan Africa. However, evidence indicates that, today, Africa could have up to 2–3-fold greater rates of stroke incidence and higher stroke prevalence than western Europe and the USA. In Africa, data published within the past decade show that stroke has an annual incidence rate of up to 316 per 100,000, a prevalence of up to 1,460 per 100,000 and a 3-year fatality rate greater than 80%. Moreover, many Africans have a stroke within the fourth to sixth decades of life, with serious implications for the individual, their family and society. This age profile is particularly important as strokes in younger people tend to result in a greater loss of self-worth and socioeconomic productivity than in older individuals. Emerging insights from research into stroke epidemiology, genetics, prevention, care and outcomes offer great prospects for tackling the growing burden of stroke on the continent. In this article, we review the unique profile of stroke in Africa and summarize current knowledge on stroke epidemiology, genetics, prevention, acute care, rehabilitation, outcomes, cost of care and awareness. We also discuss knowledge gaps, emerging priorities and future directions of stroke medicine for the more than 1 billion people who live in Africa., In this Review, Akinyemi and colleagues provide an overview of stroke in Africa, including epidemiology, risk factors, genetics and available stroke services. The authors also discuss the future of stroke care in Africa, highlighting the promise of biobanking and novel leadership initiatives., Key points The annual incidence rate of stroke in Africa is up to 316 per 100,000 individuals, which is within the highest incidence rates in the world, and the prevalence rate of 1,460 per 100,000 reported in one region of Nigeria, western Africa, is clearly among the highest in the world.Hypertension remains the most important modifiable risk factor for stroke in Africa but others include diabetes mellitus, dyslipidaemia, obesity, stress, smoking, alcohol use, physical inactivity and an unhealthy diet.Africa has a slightly greater preponderance of small vessel disease-related stroke and intracerebral haemorrhagic lesions than elsewhere in the world.The results of the first African genome-wide association study on stroke are expected soon but genes already known to modify stroke risk in African populations include IL6, APOE, APOL1, CYB11B2 and CDKN2A/2B.Pragmatic approaches to improving stroke care in Africa include regular monitoring of risk factors and health services, implementation of prevention strategies, improving acute care and rehabilitation services, and encouraging task sharing; the emergence of standalone stroke care and stroke units in some North African and sub-Saharan countries is encouraging.Numerous challenges face stroke medicine in Africa but awareness and the concerted efforts towards securing support for more stroke research and services via organizations such as the African Stroke Organization, World Stroke Organization and WHO hold much promise.

Africa is the world’s most genetically diverse, second largest, and second most populous continent, with over one billion people distributed across 54 countries. With a 23% lifetime risk of stroke, Africa has some of the highest rates of stroke worldwide and many occur in the prime of life with huge economic losses and grave implications for the individual, family, and the society in terms of mental capital, productivity, and socioeconomic progress. Tackling the escalating burden of stroke in Africa requires prioritized, multipronged, and inter-sectoral strategies tailored to the unique African epidemiological, cultural, socioeconomic, and lifestyle landscape. The African Stroke Organization (ASO) is a new pan-African coalition that brings together stroke researchers, clinicians, and other health-care professionals with participation of national and regional stroke societies and stroke support organizations. With a vision to reduce the rapidly increasing burden of stroke in Africa, the ASO has a four-pronged focus on (1) research, (2) capacity building, (3) development of stroke services, and (4) collaboration with all stakeholders. This will be delivered through advocacy, awareness, and empowerment initiatives to bring about people-focused changes in policy, clinical practice, and public education. In the spirit of the African philosophy of Ubuntu “I am because we are,” the ASO will harness the power of diversity, inclusiveness, togetherness, and team work to build a strong, enduring, and impactful platform for tackling stroke in Africa.

Background Discovering biomarkers for dementia is a pivotal step toward successful early diagnosis and treatment. Although plasma biomarkers have been explored, no consensus has been reached. Alpha-synuclein (AS), a 14 kDa synaptic protein associated with several neurodegenerative diseases, exists natively within erythrocytes (ERC). This protein is characteristic of Lewy body diseases, in which it aggregates into toxic Lewy bodies. As ERC are implicated in dementia, they are a potential target for future biomarkers. Objective The aims of this study were to assess AS levels within ERC and whether AS can be used as a peripheral biomarker to differentiate between dementia and aged matched healthy control subjects. Methods A total of 114 samples (60 aging controls, 36 Alzheimer's disease, 12 vascular dementia (VaD) and 6 dementia with Lewy bodies (DLB) subjects) were analyzed. We used Bradford assay to measure protein concentration, indirect ELISA to detect levels of AS, and immunoblotting to identify AS composition. Data were analyzed with nonparametric tests. Results AS oligomers were present in dementia blood samples, whereas in controls, AS was largely monomeric. There was a significant increase in AS levels in DLB whole blood (p = 0.005; Kruskal-Wallis test), with a sensitivity and specificity of 100.0% and 93.9%. Protein concentrations in ERC isolated at pH 5.7 were significantly increased in dementia patients compared to controls (17.58 versus 40.33μg/ml; p≤0.005; Mann-Whitney test). In the VaD group, the protein concentration in the pH5.7 ERC fraction had sensitivity and specificity of 91.7% and 62.1%. Conclusions ERC protein concentration and AS levels have a potential for development of a novel diagnostic dementia blood test.

BACKGROUND: Laboratory - based studies of neurological disease patterns and mechanisms are sparse in sub- Saharan Africa. However, availability of human brain tissue resource depends on willingness towards brain donation. This study evaluated the level of willingness among outpatient clinic attendees in a Nigerian teaching hospital. METHODS: Under the auspices of the IBADAN Brain Bank Project, a 43 – item semi - structured interviewer – administered questionnaire was designed to evaluate knowledge, attitude, and beliefs of individuals attending Neurology, Psychiatry and Geriatrics Outpatient clinics regarding willingness to donate brain for research. Association between participants characteristics and willingness towards brain donation was investigated using logistic regression models. Analysis was conducted using Stata SE version 12.0. RESULTS: A total of 412 participants were interviewed. Their mean age was 46.3 (16.1) years. 229 (55.6%) were females and 92.5% had at least 6 years of formal education. Overall, 109 (26.7%) were willing to donate brains for research. In analyses adjusting for educational status, religion, ethnicity, marital status and family setting, male sex showed independent association with willingness towards brain donation OR (95% C.I) = 1.7 (1.08 – 2.69), p = 0.023. Participants suggested public engagement and education through mass media (including social media) and involvement of religious and community leaders as important interventions to improve awareness and willingness towards brain donation. CONCLUSION: The survey revealed low willingness among outpatient clinic attendees to donate brain for research, although men were more inclined to donate. It is imperative to institute public engagement and educational interventions in order to improve consent for brain donation for research.

Introduction Genomic research and neurobiobanking are expanding globally. Empirical evidence on the level of awareness and willingness to donate/share biological samples towards the expansion of neurobiobanking in sub-Saharan Africa is lacking. Aims To ascertain the awareness, perspectives and predictors regarding biological sample donation, sharing and informed consent preferences among community members in Ghana and Nigeria. Methods A questionnaire cross-sectional survey was conducted among randomly selected community members from seven communities in Ghana and Nigeria. Results Of the 1015 respondents with mean age 39.3 years (SD 19.5), about a third had heard of blood donation (37.2%, M: 42.4%, F: 32.0%, p = 0.001) and a quarter were aware of blood sample storage for research (24.5%; M: 29.7%, F: 19.4%, p = 0.151). Two out of ten were willing to donate brain after death (18.8%, M: 22.6%, F: 15.0%, p Conclusion There is a greater need for research attention in the area of brain banking and informed consent. Improved context-sensitive public education on neurobiobanking and informed consent, in line with the sociocultural diversities, is recommended within the African sub region.

Brain arteriolosclerosis (B-ASC), characterized by pathologic arteriolar wall thickening, is a common finding at autopsy in aged persons and is associated with cognitive impairment. Hypertension and diabetes are widely recognized as risk factors for B-ASC. Recent research indicates other and more complex risk factors and pathogenetic mechanisms. Here, we describe aspects of the unique architecture of brain arterioles, histomorphologic features of B-ASC, relevant neuroimaging findings, epidemiology and association with aging, established genetic risk factors, and the co-occurrence of B-ASC with other neuropathologic conditions such as Alzheimer's disease and limbic-predominant age-related TDP-43 encephalopathy (LATE). There may also be complex physiologic interactions between metabolic syndrome (e.g., hypertension and inflammation) and brain arteriolar pathology. Although there is no universally applied diagnostic methodology, several classification schemes and neuroimaging techniques are used to diagnose and categorize cerebral small vessel disease pathologies that include B-ASC, microinfarcts, microbleeds, lacunar infarcts, and cerebral amyloid angiopathy (CAA). In clinical-pathologic studies that factored incomorbid diseases, B-ASC was independently associated with impairments of global cognition, episodic memory, working memory, and perceptual speed, and has been linked to autonomic dysfunction and motor symptoms including parkinsonism. We conclude by discussing critical knowledge gaps related to B-ASC and suggest that there are probably subcategories of B-ASC that differ in pathogenesis. Observed in over 80% of autopsied individuals beyond 80years of age, B-ASC is a complex and under-studied contributor to neurologic disability.

Assessment of outcome in preclinical studies of vascular cognitive impairment (VCI) is heterogenous. Through an ARUK Scottish Network supported questionnaire and workshop (mostly UK-based researchers), we aimed to determine underlying variability and what could be implemented to overcome identified challenges. Twelve UK VCI research centres were identified and invited to complete a questionnaire and attend a one-day workshop. Questionnaire responses demonstrated agreement that outcome assessments in VCI preclinical research vary by group and even those common across groups, may be performed differently. From the workshop, six themes were discussed: issues with preclinical models, reasons for choosing functional assessments, issues in interpretation of functional assessments, describing and reporting functional outcome assessments, sharing resources and expertise, and standardization of outcomes. Eight consensus points emerged demonstrating broadly that the chosen assessment should reflect the deficit being measured, and therefore that one assessment does not suit all models; guidance/standardisation on recording VCI outcome reporting is needed and that uniformity would be aided by a platform to share expertise, material, protocols and procedures thus reducing heterogeneity and so increasing potential for collaboration, comparison and replication. As a result of the workshop, UK wide consensus statements were agreed and future priorities for preclinical research identified.

The ethical, legal, and social implications (ELSI) of emerging neurobiobanks and data resources are unclear in an African scientific landscape with unique cultural, linguistic, and belief systems. The overarching goal of the African Neurobiobank for Precision Stroke Medicine–—ELSI Project is to identify, examine, and develop novel approaches to address ELSI issues of biobanking and stroke genomic research in sub-Saharan Africa (SSA). To accomplish the goal we will (1) explore knowledge, attitude, perceptions, barriers, and facilitators influencing ELSI issues related to biobanking and stroke genomic research; (2) use information obtained to craft a community intervention program focused on ELSI issues; and (3) build capacity and careers related to genomics and biobanking for effective client/community engagement while enhancing regulatory, governance, and implementation competences in biobanking science in SSA. A community-based participatory research and mixed-methodological approach, focused on various levels of the social ecological model, will be used to identify and examine relevant ELSI issues. Contextual intervention tools, platforms, and practices will be developed to enhance community understanding and participation in stroke biobanking and genomics research activities while facilitating enduring trust, and equitable and fair utilization of biobanking resources for genetic and trans-omics research. A concurrent capacity building program related to genetic counseling and biobanking will be implemented for early career researchers. The huge potential for neurobiobanking and genomics research in Africa to advance precision medicine applicable to stroke and other neurological disorders requires addressing ELSI challenges while building sustainable research, career, and regulatory capacities in trans-omics and biobanking science.

In the paper by Mok et al. (“Tackling challenges in care of Alzheimer's disease and other dementias amid the COVID-19 pandemic, now and in the future.”Alzheimer's Dement. 2020; 16: 1571-1581. https://doi.org/10.1002/alz.12143), an error occurred in the preparation of the paper for publication, requiring the following correction. In the initial publication of this article, Vorapun Senanarong, BSc, MD, was inadvertently omitted from the author group. The corrected author group and affiliations list appear above. We regret the error.

Peripheral biomarkers for dementia are few and far between. Despite research into blood plasma/serum biomarkers for dementia diagnostics, there is a lack of information on erythrocytes and their vast proteomes as potential biomarkers. This review identifies a number of relevant and potentially promising erythrocyte biomarkers for various subtypes of dementia. These include erythrocyte morphology, oxidative stress, and erythrocyte membrane proteins such as the glucose transporter (GLUT-1), amyloid-β, IgG, Hsp90, calpain-1, and band 3 protein. Of those proteins identified Hsp90, amyloid-β, calpain-1 and band 3 show the most promise as pre-clinical biomarkers. However, the most intriguing aspect of erythrocytes is their changed morphology in dementia. The altered morphology not only could be used as a diagnostic biomarker but may be crucial in early pathogenesis of the disease. Further work must be done to establish the pathological connection between the periphery and central disease processes.

BackgroundThere is a newly emergent ageing population of people living with HIV (PLWH) in Africa. However, there is little research into HIV-associated neurocognitive disorder (HAND) in this population. Existing research suggests HAND is prevalent however the aetiology remains unclear. This study aims to determine whether HAND is truly prevalent and explore potential causes in PLWH on c-ART using objective structural measures.AimsExplore whether substantial atrophy and/or white matter hyperintensities (WMH) is present on the clinical magnetic resonance imaging (MRI) reports and quantitative analysis of people with optimally managed HIV in Northern Tanzania.Explore the aetiology of HAND by assessing whether cerebral atrophy and/or WMH is associated with demographic risk factors, HIV–related factors and/or comorbidities.Investigate whether structural damage is related to objectively measured cognitive impairment, and whether this is a subcortical or cortical impairment.Explore which neurocognitive test is the best predictor of structural damage and therefore most valid diagnostic test for HAND.MethodsA systematic sample of PLWH aged ≥ 50 were recruited from a HIV clinic in Kilimanjaro, Tanzania. Demographic data and comorbidities were self-reported. HIV-disease management data were obtained. Viral load and CD4 count were measured. A neurocognitive battery and informant history of functional impairment identified HAND. Cerebral atrophy (brain and ventricle volume) and WMH were measured using quantitative analysis of 1.5T MRI.Preliminary resultsThis cohort (n=91) had well-managed HIV (75.9% suppressed viral load, median CD4 507 cells/ul). The significant independent predictor (IP) of decreased brain volume was older age at HIV diagnosis (p=.001), and of increased ventricle volume was increased age (pConclusionsThis is the first MRI study of older c-ART treated PLWH in Africa. Despite c-ART and good disease management, HAND was objectively prevalent and unrelated to measures of HIV. Cerebral atrophy and WMH were associated with factors of neurodegeneration. Cerebral atrophy was associated with male gender and age at diagnosis (legacy effect).

Vascular cognitive impairment (VCI), including its severe form, vascular dementia (VaD), is the second most common form of dementia. The genetic etiology of sporadic VCI remains largely unknown. We previously conducted a systematic review and meta-analysis of all published genetic association studies of sporadic VCI prior to 6 July 2012, which demonstrated that APOE (ɛ4, ɛ2) and MTHFR (rs1801133) variants were associated with susceptibility for VCI. De novo genotyping was conducted in a new independent relatively large collaborative European cohort of VaD (nmax = 549) and elderly non-demented samples (nmax = 552). Where available, genotype data derived from Illumina's 610-quad array for 1210 GERAD1 control samples were also included in analyses of genes examined. Associations were tested using the Cochran-Armitage trend test: MTHFR rs1801133 (OR = 1.36, 95% CI 1.16-1.58, p =

Deposition of amyloid β (Aβ) in the walls of cerebral arteries as cerebral amyloid angiopathy (CAA) suggests an age-related failure of perivascular drainage of soluble Aβ from the brain. As CAA is associated with Alzheimer's disease and with intracerebral haemorrhage, the present study determines the unique sequence of changes that occur as Aβ accumulates in artery walls. Paraffin sections of post-mortem human occipital cortex were immunostained for collagen IV, fibronectin, nidogen 2, Aβ and smooth muscle actin and the immunostaining was analysed using Image J and confocal microscopy. Results showed that nidogen 2 (entactin) increases with age and decreases in CAA. Confocal microscopy revealed stages in the progression of CAA: Aβ initially deposits in basement membranes in the tunica media, replaces first the smooth muscle cells and then the connective tissue elements to leave artery walls completely or focally replaced by Aβ. The pattern of development of CAA in the human brain suggests expansion of Aβ from the basement membranes to progressively replace all tissue elements in the artery wall. Establishing this full picture of the development of CAA is pivotal in understanding the clinical presentation of CAA and for developing therapies to prevent accumulation of Aβ in artery walls. This article is part of a Special Issue entitled: Vascular Contributions to Cognitive Impairment and Dementia edited by M. Paul Murphy, Roderick A. Corriveau and Donna M. Wilcock., Highlights • Lymphatic drainage of the brain is along basement membranes in the walls of arteries. • Perivascular lymphatic drainage fails with age and arteriosclerosis. • Aβ deposits in the perivascular drainage pathways of leptomeningeal arteries as CAA. • As CAA progresses, Aβ replaces all elements of the ageing artery wall. • Facilitation of perivascular drainage may prevent CAA and delay Alzheimer's disease.

Recent epigenome-wide association studies in Alzheimer's disease have highlighted consistent robust neuropathology-associated DNA hypermethylation of the ankyrin 1 (ANK1) gene in the cortex. The extent to which altered ANK1 DNA methylation is also associated with other neurodegenerative diseases is not currently known. In the present study, we used bisulfite pyrosequencing to quantify DNA methylation across 8 CpG sites within a 118 bp region of the ANK1 gene across multiple brain regions in Alzheimer's disease, Vascular dementia, Dementia with Lewy bodies, Huntington's disease, and Parkinson's disease. We demonstrate disease-associated ANK1 hypermethylation in the entorhinal cortex in Alzheimer's disease, Huntington's disease, and Parkinson's disease, whereas in donors with Vascular dementia and Dementia with Lewy bodies, we observed elevated ANK1 DNA methylation only in individuals with coexisting Alzheimer's disease pathology. We did not observe any disease-associated differential ANK1 DNA methylation in the striatum in Huntington's disease or the substantia nigra in Parkinson's disease. Our data suggest that ANK1 is characterized by region and disease-specific differential DNA methylation in multiple neurodegenerative diseases.

Increasing evidence recognizes Alzheimer's disease (AD) as a multifactorial and heterogeneous disease with multiple contributors to its pathophysiology, including vascular dysfunction. The recently updated AD Research Framework put forth by the National Institute on Aging-Alzheimer's Association describes a biomarker-based pathologic definition of AD focused on amyloid, tau, and neuronal injury. In response to this article, here we first discussed evidence that vascular dysfunction is an important early event in AD pathophysiology. Next, we examined various imaging sequences that could be easily implemented to evaluate different types of vascular dysfunction associated with, and/or contributing to, AD pathophysiology, including changes in blood-brain barrier integrity and cerebral blood flow. Vascular imaging biomarkers of small vessel disease of the brain, which is responsible for >50% of dementia worldwide, including AD, are already established, well characterized, and easy to recognize. We suggest that these vascular biomarkers should be incorporated into the AD Research Framework to gain a better understanding of AD pathophysiology and aid in treatment efforts. (C) 2018 the Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

Brain banks are biorepositories of central nervous system (CNS) tissue including fixed and frozen whole brains, brain biopsies and spinal cord, as well as body fluids comprising the cerebrospinal fluid (CSF) and blood stored for research purposes. Though several independent brain banks exist in high income countries, only five low- and middle - income countries (LMIC) have brain banks. The African continent is yet to establish a formalized brain bank despite its huge human genomic diversity, ageing of her populations with concomitant increases in ageing - associated brain disorders and differential phenotypic expression and outcomes of brain disorders. Cellular and molecular clinicopathological studies are vital to shaping our understanding of the interaction between racial (genetic) and geographical (environmental) factors in the natural history and mechanisms of disease, and unravelling frameworks of diagnostic biomarkers, and new therapeutic and preventative interventions. The Ibadan Brain Ageing, Dementia And Neurodegeneration (IBADAN) Brain Bank, the first organized brain tissue biorepository in sub - Saharan Africa, is set up to accrue, process and store unique brain tissues for future research into a broad spectrum of neurological and psychiatric disorders. The potential unique discoveries and research breakthroughs will benefit people of African ancestry and other ancestral populations.

Cerebral small vessel disease (SVD) is a major health challenge. Therapeutic approaches remain limited, hampered by the lack of mechanistic understanding and identification of therapeutic targets. Relevant animal models could provide a cornerstone to basic scientific studies of disease mechanisms and pre-clinical studies of potential therapies, but there is a critical need to improve the current translational gap that exists between pre-clinical research and treatments in patients. The Medical Research Council Dementias Platform UK (MRC DPUK) Vascular Experimental Medicine Theme identified that a comprehensive assessment of the latest developments in animal models and of their contribution to understanding of cerebral microvascular disease would reduce the translational gap. In response to this, a two day workshop took place in late January 2017 at the British Heart Foundation Centre of Research Excellence in Glasgow, Scotland in conjunction with MRC DPUK and brought together experts from several disciplines in cerebrovascular disease, dementia and cardiovascular biology, to highlight current advances in these fields, explore synergies and scope for development. There were presentations from UK and international researchers and a specific focus on animal models of cerebral microvascular disease and dementia, considering vascular biology, neurogliovascular coupling, blood-brain barrier function, neuroinflammation, cerebral drainage pathways, and methodological and translational challenges (see Figure 1 for the general organisation of the meeting including the key topics and themes discussed). This overview provides a summary of the key talks, with a particular focus on mechanisms of cerebral vascular disease (see Figure 2) and improving translation. These talks were followed by related themed discussion groups on the gaps in knowledge and requirements to advance knowledge, the outcomes of which are highlighted in Table 1. Additional related articles are published in the Special Edition of Clinical Science (http://www.portlandpresspublishing.com/cc/small-vessels).

Silent information regulator 2 homolog 1 (SIRT1) is a protein deacetylase that has been reported to suppress neurodegenerative and cardiovascular pathologies in model organisms. We have recently reported that SIRT1 overexpression preserves cerebral blood flow (CBF) after bilateral common carotid artery stenosis (∼50% stenosis) by the deacetylation of endothelial nitric oxide synthase. This study was designed to determine whether cerebral SIRT1 expression would be effective in a more severe model of cerebral ischemia caused by bilateral common carotid artery occlusion (BCAO) in vivo. Sirt1-overexpressing (Sirt1-Tg) mice (n=13) and their wild-type littermates (n=17) were subjected to BCAO for 10 min using microaneurysm clips. Temporal CBF changes were measured by laser speckle flowmetry before and 5, 10 min, and 2 h after BCAO. Histological evaluation of hippocampal changes was performed 7 days after BCAO. Histological findings were significantly less severe in Sirt1-Tg mice than in wild-type mice; wild-type mice showed strokes in the hippocampus, whereas Sirt1-Tg mice had minimal hippocampal damage 7 days after BCAO. Consistent with this observation, wild-type mice showed a severe reduction in CBF to ∼20-25% of the baseline level during BCAO, whereas Sirt1-Tg littermates showed significantly preserved CBF up to 45-50% of the baseline level. Our study provides evidence for the promising role of SIRT1 in protecting against cerebral global ischemia by preserving CBF and restoring the cerebrovascular reserve.

Cerebral small vessel disease (SVD) is a major cause of age-related cognitive impairment and dementia. The pathophysiology of SVD is not well understood and is hampered by a limited range of relevant animal models. Here, we describe gliovascular alterations and cognitive deficits in a mouse model of sustained cerebral hypoperfusion with features of SVD (microinfarcts, hemorrhage, white matter disruption) induced by bilateral common carotid stenosis. Multiple features of SVD were determined on T2-weighted and diffusion-tensor magnetic resonance imaging scans and confirmed by pathologic assessment. These features, which were absent in sham controls, included multiple T2-hyperintense infarcts and T2-hypointense hemosiderin-like regions in subcortical nuclei plus increased cerebral atrophy compared with controls. Fractional anisotropy was also significantly reduced in several white matter structures including the corpus callosum. Investigation of gliovascular changes revealed a marked increase in microvessel diameter, vascular wall disruption, fibrinoid necrosis, hemorrhage, and blood–brain barrier alterations. Widespread reactive gliosis, including displacement of the astrocytic water channel, aquaporin 4, was observed. Hypoperfused mice also demonstrated deficits in spatial working and reference memory tasks. Overall, gliovascular disruption is a prominent feature of this mouse, which could provide a useful model for early-phase testing of potential SVD treatment strategies.

H. Jokinen työryhmän jäsenenä. Introduction: Numerous diagnostic criteria have tried to tackle the variability in clinical manifestations and problematic diagnosis of vascular cognitive impairment (VCI) but none have been universally accepted. These criteria have not been readily comparable, impacting on clinical diagnosis rates and in turn prevalence estimates, research, and treatment. Methods: The Vascular Impairment of Cognition Classification Consensus Study (VICCCS) involved participants (81% academic researchers) from 27 countries in an online Delphi consensus study. Participants reviewed previously proposed concepts to develop new guidelines. Results: VICCCS had a mean of 122 (98-153) respondents across the study and a 67% threshold to represent consensus. VICCCS redefined VCI including classification of mild and major forms of VCI and subtypes. It proposes new standardized VCI-associated terminology and future research priorities to address gaps in current knowledge. Discussion: VICCCS proposes a consensus-based updated conceptualization of VCI intended to facilitate standardization in research. (C) 2016 the Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

Cognitive impairment is an important target for rehabilitation as it is common following stroke, is associated with reduced quality of life and interferes with motor and other types of recovery interventions. Cognitive function following stroke was identified as an important, but relatively neglected area during the first Stroke Recovery and Rehabilitation Roundtable (SRRR I), leading to a Cognition Working Group being convened as part of SRRR II. There is currently insufficient evidence to build consensus on specific approaches to cognitive rehabilitation. However, we present recommendations on the integration of cognitive assessments into stroke recovery studies generally and define priorities for ongoing and future research for stroke recovery and rehabilitation. A number of promising interventions are ready to be taken forward to trials to tackle the gap in evidence for cognitive rehabilitation. However, to accelerate progress requires that we coordinate efforts to tackle multiple gaps along the whole translational pathway.

Objectives Cerebral amyloid angiopathy (CAA) is associated with lobar intracerebral haemorrhage (ICH). While only the e4 allele of the apolipoprotein E (APOE) gene is associated with the presence of CAA, both APOE-e4 and e2 are associated with lobar ICH. The generally accepted explanation is that APOE-e4 promotes vascular amyloid deposition, while APOE-e2 promotes progression to severe CAA with associated vasculopathic changes that cause vessel rupture and ICH. We assessed the evidence for these allele-specific effects. Methods We systematically identified published studies with data on APOE genotype and histopathological assessment of postmortem brains for CAA severity. We obtained unpublished data from these for meta-analyses of the effects of e4-containing (e4+) and e2-containing (e2+) genotypes on progression to severe CAA. Results Of six eligible studies (543 eligible participants), data were available from 5 (497 participants, 353 with CAA). Meta-analyses showed a possible association of e4+ genotypes with severe CAA (e4+ vs e4-: severe vs mild/moderate CAA, OR 2.5, 95% CI 1.4 to 4.5, p=0.002; severe vs moderate CAA, OR 1.7, 95% CI 0.9 to 3.1, p=0.11). For e2+ versus e2- genotypes, there was no significant association, but the very small number of participants with e2+ genotypes (22) precluded reliable estimates. Conclusions We found a possible association of severe CAA with APOE-e4 but not APOE-e2. However, our findings do not exclude a biologically meaningful association between APOE-e2 and severe CAA. Further work is needed to elucidate fully the allele-specific associations of APOE with CAA and their mechanisms.

We quantified vascular changes in the frontal lobe and basal ganglia of four inherited small vessel diseases (SVDs) including cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), pontine autosomal dominant microangiopathy and leukoencephalopathy (PADMAL), hereditary multi-infarct dementia of Swedish type (Swedish hMID), and hereditary endotheliopathy with retinopathy, nephropathy, and stroke (HERNS). Vascular pathology was most severe in CADASIL, and varied with marginally greater severity in the basal ganglia compared to the frontal lobe. The overall sclerotic index values in frontal lobe were in the order CADASIL ≥ HERNS > PADMAL > Swedish hMID > sporadic SVD, and in basal ganglia CADASIL > HERNS > Swedish hMID > PADMAL> sporadic SVD. The subcortical white matter was almost always more affected than any gray matter. We observed glucose transporter-1 (GLUT-1) protein immunoreactivities were most affected in the white matter indicating capillary degeneration whereas collagen IV (COL4) immunostaining was increased in PADMAL cases in all regions and tissue types. Overall, GLUT-1 : COL4 ratios were higher in the basal ganglia indicating modifications in capillary density compared to the frontal lobe. Our study shows that the extent of microvascular degeneration varies in these genetic disorders exhibiting common end-stage pathologies but is the most aggressive in CADASIL.

Sir, Our aim in developing the vascular cognitive impairment neuropathological guidelines (VCING) was to establish criteria that we could show to be highly reproducible between neuropathologists in different centres, for post-mortem assessment of the likelihood that cognitive impairment was attributable to cerebrovascular pathology. To ensure reproducibility, we performed blinded post-mortem assessment of sections of brain tissue that were circulated to nine neuropathologists in centres across the UK. The advantage of this approach was that it enabled us to develop a protocol that can easily and reliably be applied in centres other than those participating in the VCING project. However, as noted by Oveisgharan and Hachinski (2016), our approach did impose certain practical constraints on the scope …

Background Existing rodent models of vascular cognitive impairment (VCI) show abrupt changes in cerebral blood flow (CBF) and do not reliably replicate the clinical pathogenesis of VCI. We therefore aimed to develop a mouse model of VCI where CBF is gradually reduced, followed by subsequent progressive motor and cognitive impairment, after surgical intervention. Methods and Results Adult C57BL/6J male mice were subjected to gradual common carotid artery stenosis (GCAS) surgery by using an ameroid constrictor vessel‐constricting device with an inner diameter of 0.75 mm. The common carotid arteries narrowed gradually after gradual constriction of ameroid constrictors over 28 days after GCAS, with subsequent 79.3% area stenosis as a result of smooth muscle cell proliferation and macrophage infiltration in the tunica intima. The 28‐day survival rate was 91%. Arterial spin labeling demonstrated gradual and continuous reduction of cortical and subcortical CBF (ratio to the preoperative value) to 54.6% and 51.5%, respectively, over 28 days. However, magnetic resonance angiography showed increment of collateral flow signals in the leptomeningeal artery. Rarefaction and proliferation of astrocytes and microglia, with loss of oligodendrocytes, were found in the white matter at 32 days. Hippocampal neuronal loss was observed in only 25% of GCAS mice, consistent with lack of abnormalities in the Morris water maze test. The rotarod test showed motor impairment, and the Y‐maze test showed working memory deficits. Conclusions The GCAS model successfully generated gradual and continuous CBF reduction over 28 days, with replication of key histological, radiological, and behavioral features associated with cerebral hypoperfusion leading to VCI.

Background/Aims: Genetic risk factors have not been clearly established for vascular dementias (VaD) related to stroke and cerebrovascular disease. Methods: Samples were genotyped for APOE, MTHFR and ICAM. Aβ levels and choline acetyltransferase (ChAT) activities were assayed in controls and individuals with VaD. Results: Associations were found between the APOE-Ε4 allele and mixed dementia, infarct/stroke dementia and subcortical ischemic vascular dementia (SIVD), and higher Aβ1-42 levels and decreased ChAT activity. MTHFR was more associated with SIVD, mixed dementia, and lower ChAT activity. Conclusions: The study demonstrates important differences in the genetic associations of VaD and begins to clarify the genetic basis of key pathological substrates.

The Dorsal Motor Nucleus of Vagus (DMV) is degenerated in many patients with early stage Lewy Body Diseases (LBD). Many patients with LBD also develop symptomatic autonomic dysfunction prior to motor and cognitive symptoms. The DMV, along with the Nucleus Ambiguous (NA) and Raphe Obscurus (RO) regulates a variety of autonomic reflexes, suggesting that there may be an association between the degree of neurodegenerative protein aggregation in the DMV and symptomatic autonomic dysfunction in patients with LBD. Using digital in vivo pathology, we quantified alphasynuclein, tau, ubiquitin and Heat Shock Protein 27 (HSP27) containing neurons in the DMV, NA, RO, in addition to the hypoglossal nucleus in 12 LBD patients. alphaSynuclein, ubiquitin and tau aggregates most greatly affected the DMV followed by the NA, RO, but never the hypoglossal nucleus. There was a positive correlation between DMV alphasynuclein and tau aggregation (p

Vascular dementia accounts for approximately 15-20% of all dementias. In addition, a significant subset of people with Alzheimer's disease have concurrent cerebrovascular disease. Vascular dementia is caused by different cerebrovascular morphological abnormalities including large artery territory infarction (multi-infarct vascular dementia) and sub-cortical ischaemic vascular dementia. Despite this distinction, there is a lack of studies examining the neurochemistry of individual vascular dementia subtypes. Serotonin is believed to play an important role in cognition, and serotonin receptors may provide a novel target for future anti-dementia therapeutics. This study aimed to determine levels of two serotonin receptors in subtypes of vascular dementia and relate any changes to cognition. We have determined, using saturation radioligand binding, the binding parameters (affinity and maximal binding) of ((3)H)-WAY 100635 binding to 5-HT(1A) receptors and ((3)H)-ketanserin binding to 5-HT(2A) receptors in post-mortem tissue from the frontal and temporal cortices of patients with either multi-infarct vascular dementia, sub-cortical ischaemic vascular dementia, mixed Alzheimer's disease/vascular dementia or stroke no dementia (SND). 5-HT(1A) and 5-HT(2A) receptor binding was significantly increased in the temporal cortex of patients with either multi-infarct vascular dementia or SND, compared to age-matched controls. 5-HT(1A) receptor maximal binding in the temporal cortex was also positively correlated with cognition as determined by Mini-Mental State Examination (MMSE) and Cambridge Assessment of Mental Health for the Elderly scores (CAMCOG). These results reveal an important distinction between the neurochemistry of multi-infarct vascular dementia/SND and sub-cortical ischaemic vascular dementia, suggesting that pharmacological manipulation of serotonin offers the possibility to develop novel therapies for stroke and multi-infarct vascular dementia patients. The results also highlight the importance of the cortical 5-HT(1A) receptor in mediating cognition.

Background/Aim: Alterations in cholinergic activity have not been systematically studied in types of cerebrovascular disease. We examined cholinergic function at postmortem, focussing on stroke and vascular dementia (VaD). Methods: Post-mortem brain tissue was studied from 61 patients with stroke or VaD (13 infarct dementia; 8 stroke/no dementia; 11 sub-cortical ischaemic VaD, SIVD; 29 VaD and concurrent Alzheimer’s disease, AD), 12 patients with AD and 23 controls. Choline acetyltransferase (ChAT) was measured in Brodmann areas (BA) 9 and 20/21. Results: There were significant reductions in ChAT activity in patients with VaD and concurrent AD compared to age-matched controls (BA9: t = 2.7, p = 0.009; BA20/21: t = 4.67, p = 0.000). In patients with infarct dementia, there was a significant 27% increase in ChAT activity in BA9 (t = 2.1, p = 0.047), but not in BA20/21 (t = 1.67, p = 0.106), compared to the age-matched control group. There was no relationship between ChAT activity and cognition in the VaD patients. Conclusions: Loss of cholinergic function is only evident in VaD patients with concurrent AD. A novel increase in cholinergic activity was identified in patients with infarct dementia, which may create important new treatment opportunities.

Vascular dementia (VaD) accounts for about 20% of all dementias, and vascular risk is a key factor in more than 40% of people with Alzheimer’s disease (AD). Little is known about inflammatory processes in the brains of these individuals. We have examined inflammatory mediators (interleukin (IL)-1β, IL-1α, IL-6 and tumour necrosis factor α) and chemokines (macrophage inflammatory protein 1, monocyte chemo-attractant protein (MCP)-1 and granulocyte macrophage colony-stimulating factor) in brain homogenates from grey and white matter of the frontal cortex (Brodmann area 9) from patients with VaD (n = 11), those with concurrent VaD and AD (mixed dementia; n = 8) and from age-matched controls (n = 13) using ELISA assays. We found a dramatic reduction of MCP-1 levels in the grey matter in VaD and mixed dementia in comparison to controls (55 and 66%, respectively). IL-6 decreases were also observed in the grey matter of VaD and mixed dementia (72 and 71%, respectively), with a more modest decrease (30%) in the white matter of patients with VaD or mixed dementia. In the first study to examine the status of inflammatory mediators in a brain region severely affected by white-matter lesions, our findings highlight – in contrast to previous reports in AD – that patients at the later stage of VaD or mixed dementia have a significantly attenuated neuro-inflammatory response.

Rationale: Existing rodent models of vascular cognitive impairment (VCI) show abrupt change in cerebral blood flow (CBF) and do not completely mirror clinical pathogenesis of VCI. Objective: To establish a mouse model of VCI where CBF gradually decreases with subsequent motor and cognitive impairment. Methods and Results: Adult C57BL/6J male mice were subjected to gradual common carotid artery stenosis (GCAS) surgery using an ameroid constrictor (AC) vessel-constricting device with inner diameter of 0.75 mm. The common carotid arteries narrowed gradually after gradual constriction of ACs over 28 days after GCAS, with subsequent 79.3% area stenosis due to smooth muscle cell proliferation and macrophage infiltration in the tunica intima. The 28-day survival rate was 100%. Arterial spin labeling demonstrated gradual and continuous reduction of cortical and subcortical CBF (ratio to the preoperative value) to 54.6% and 51.5%, respectively, over 28 days. However, magnetic resonance angiography showed increment of collateral flow signals in the leptomeningeal artery. Rarefaction and proliferation of astrocytes and microglia with loss of oligodendrocytes was found in the white matter at 32 days. Hippocampal neuronal loss was observed in only 25% of GCAS mice, consistent with lack of abnormalities in the Morris water maze test. The rotarod test showed motor impairment whereas the Y-maze test showed that working memory was impaired. Conclusions: The GCAS model successfully generated gradual and continuous CBF reduction over 28 days, with replication of key histological, radiological, and behavioral features associated with cerebral hypoperfusion leading to VCI.

A nonsense/protein chain-terminating mutation in the CHMP2B gene has recently been reported as a cause of frontotemporal dementia (FTD) in the single large family known to show linkage to chromosome 3. Screening for mutations in this gene in a large series of FTD families and individual patients led to the identification of a protein-truncating mutation in 2 unaffected members of an Afrikaner family with FTD, but not in their affected relatives. The putative pathogenicity of CHMP2B mutations for dementia is discussed.

Accumulating evidence suggests that butyrylcholinesterase (BuChE) plays an important role in the progression of cognitive deficits and Alzheimer-type pathology in dementia patients. We examined the relationship between the K variant of BuChE and the severity of deposits of amyloid (Aβ1–42) and phosphorylated tau in the temporal cortex (BA36) of 30 prospectively studied autopsy-diagnosed dementia (Alzheimer’s disease and dementia with Lewy bodies) patients. There was 42% less phosphorylated tau in BA36 in cases with ≧1 K compared with those with wild-type BuChE alleles (t = 2.2, p = 0.039), but no difference in the extent of Aβ1–42 deposition. BuChE may play this role in the phosphorylation of tau, relevant to therapeutic inhibition of the enzyme.