Spatial relation between microbleeds and amyloid deposits in amyloid angiopathy.
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ABSTRACT:
SUBMITTER: Dierksen GA
PROVIDER: S-EPMC2964411 | biostudies-literature | 2010 Oct
REPOSITORIES: biostudies-literature
Publications
Spatial relation between microbleeds and amyloid deposits in amyloid angiopathy.
Dierksen Gregory A GA Skehan Maureen E ME Khan Muhammad A MA Jeng Jed J Nandigam R N Kaveer RN Becker John A JA Kumar Ashok A Neal Krista L KL Betensky Rebecca A RA Frosch Matthew P MP Rosand Jonathan J Johnson Keith A KA Viswanathan Anand A Salat David H DH Greenberg Steven M SM
Annals of neurology 20101001 4
Advanced cerebrovascular β-amyloid deposition (cerebral amyloid angiopathy, CAA) is associated with cerebral microbleeds, but the precise relationship between CAA burden and microbleeds is undefined. We used T2*-weighted magnetic resonance imaging (MRI) and noninvasive amyloid imaging with Pittsburgh Compound B (PiB) to analyze the spatial relationship between CAA and microbleeds. On coregistered positron emission tomography (PET) and MRI images, PiB retention was increased at microbleed sites c ...[more]
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Project description:BackgroundThe key imaging features of cerebral amyloid angiopathy (CAA) are lobar, cortical, or cortico-subcortical microbleeds, macrohaemorrhages and cortical superficial siderosis (cSS). In contrast, hypertensive angiopathy is characterized by (micro) haemorrhages in the basal ganglia, thalami, periventricular white matter or the brain stem. Another distinct form of haemorrhagic microangiopathy is mixed cerebral microbleeds (mixed CMB) with features of both CAA and hypertensive angiopathy. The distinction between the two entities (CAA and mixed CMB) is clinically relevant because the risk of haemorrhage and stroke should be well balanced if oral anticoagulation is indicated in CAA patients. We aimed to comprehensively compare these two entities.MethodsPatients with probable CAA according to the modified Boston criteria and mixed CMB without macrohaemorrhage were retrospectively identified from our database. Comprehensive comparison regarding clinical and radiological parameters was performed between the two cohorts.ResultsPatients with CAA were older (78 ± 8 vs. 74 ± 9 years, p = 0.036) and had a higher prevalence of cSS (19% vs. 4%, p = 0.027) but a lower prevalence of lacunes (73% vs. 50%, p = 0.018) and deep lacunes (23% vs. 51%, p = 0.0003) compared to patients with mixed CMB. Logistic regression revealed an association between the presence of deep lacunes and mixed CMB. The other collected parameters did not reveal a significant difference between the two groups.ConclusionsCAA and mixed CMB demonstrate radiological differences in the absence of macrohaemorrhages. However, more clinically available biomarkers are needed to elucidate the contribution of CAA and hypertensive angiopathy in mixed CMB patients.
| S-EPMC7674181 | biostudies-literature
Project description:Cerebral amyloid angiopathy (CAA) is a neurovascular disease that is strongly associated with an increase in the number and size of spontaneous microbleeds. Conventional methods of magnetic resonance imaging for detection of microbleeds, and positron emission tomography with Pittsburgh Compound B imaging for amyloid deposits, can separately demonstrate the presence of microbleeds and CAA in affected brains in vivo; however, there still is a critical need for strong evidence that shows involvement of CAA in microbleed formation. Here, we show in a Tg2576 mouse model of Alzheimer's disease, that the combination of histochemical staining and an optical clearing method called optical histology, enables simultaneous, co-registered three-dimensional visualization of cerebral microvasculature, microbleeds, and amyloid deposits. Our data suggest that microbleeds are localized within the brain regions affected by vascular amyloid deposits. All observed microhemorrhages (n=39) were in close proximity (0 to 144 ?m) with vessels affected by CAA. Our data suggest that the predominant type of CAA-related microbleed is associated with leaky or ruptured hemorrhagic microvasculature. The proposed methodological and instrumental approach will allow future study of the relationship between CAA and microbleeds during disease development and in response to treatment strategies.
| S-EPMC4814270 | biostudies-literature
Project description:Cerebral amyloid angiopathy (CAA), where beta-amyloid (Aβ) deposits around cerebral blood vessels, is a major contributor of vascular dysfunction in Alzheimer's disease (AD) patients. However, the molecular mechanism underlying CAA formation and CAA-induced cerebrovascular pathology is unclear. Hereditary cerebral amyloid angiopathy (HCAA) is a rare familial form of CAA in which mutations within the (Aβ) peptide cause an increase in vascular deposits. Since the interaction between Aβ and fibrinogen increases CAA and plays an important role in cerebrovascular damage in AD, we investigated the role of the Aβ-fibrinogen interaction in HCAA pathology. Our work revealed the most common forms of HCAA-linked mutations, Dutch (E22Q) and Iowa (D23N), resulted in up to a 50-fold stronger binding affinity of Aβ for fibrinogen. In addition, the stronger interaction between fibrinogen and mutant Aβs led to a dramatic perturbation of clot structure and delayed fibrinolysis. Immunofluorescence analysis of the occipital cortex showed an increase of fibrin(ogen)/Aβ codeposition, as well as fibrin deposits in HCAA patients, compared to early-onset AD patients and nondemented individuals. Our results suggest the HCAA-type Dutch and Iowa mutations increase the interaction between fibrinogen and Aβ, which might be central to cerebrovascular pathologies observed in HCAA.
| S-EPMC7322009 | biostudies-literature
Project description:BackgroundCerebral amyloid angiopathy (CAA) is characterized by extracellular deposition of amyloid ? (A?) around cerebral arteries and capillaries and leads to an increased risk for vascular dementia, spontaneous lobar hemorrhage, convexal subarachnoid hemorrhage, and transient focal neurological episodes, which might be an indicator of imminent spontaneous intracerebral hemorrhage. In CAA cerebral microbleeds (cMBs) with a cortical/juxtacortical distribution are frequently observed in standard magnetic resonance imaging (MRI). In vivo MRI of transgenic mouse models of CAA may serve as a useful tool to investigate translational aspects of the disease.Materials and methodsAPP23-transgenic mice demonstrate cerebrovascular A? deposition with subsequent neuropathological changes characteristic for CAA. We performed a 9.4 Tesla high field MRI study using T2, T2* and time of flight-magnetic resonance angiograpy (TOF-MRA) sequences in APP23-transgenic mice and wildtype (wt) littermates at the age of 8, 12, 16, 20 and 24 months, respectively. Numbers, size, and location of cMBs are reported.ResultsT2* imaging demonstrated cMBs (diameter 50-300 ?m) located in the neocortex and, to a lesser degree, in the thalamus. cMBs were detected at the earliest at 16 months of age. Numbers increased exponentially with age, with 2.5 ± 2 (median ± interquartilrange) at 16 months, 15 ± 6 at 20 months, and 31.5 ± 17 at 24 months of age, respectively.ConclusionWe report the temporal and spatial development of cMBs in the aging APP23-transgenic mouse model which develops characteristic pathological patterns known from human CAA. We expect this mouse model to serve as a useful tool to non-invasively monitor mid- and longterm translational aspects of CAA and to investigate experimental therapeutic strategies in longitudinal studies.
| S-EPMC4937037 | biostudies-literature
Project description:Deposition of amyloid ? (A?) in the walls of cerebral arteries as cerebral amyloid angiopathy (CAA) suggests an age-related failure of perivascular drainage of soluble A? 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 A? accumulates in artery walls. Paraffin sections of post-mortem human occipital cortex were immunostained for collagen IV, fibronectin, nidogen 2, A? 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: A? 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 A?. The pattern of development of CAA in the human brain suggests expansion of A? 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 A? 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.
| S-EPMC4827375 | biostudies-literature
Project description:Several pieces of evidence suggest that blood-brain barrier (BBB) dysfunction is implicated in the pathophysiology of Alzheimer's disease (AD), exemplified by the frequent occurrence of cerebral amyloid angiopathy (CAA) and the defective clearance of Aβ peptides. However, the specific role of brain microvascular cells in these anomalies remains elusive. In this study, we validated by Western, ELISA and immunofluorescence analyses a procedure to generate microvasculature-enriched fractions from frozen samples of human cerebral cortex. We then investigated Aβ and proteins involved in its clearance or production in microvessel extracts generated from the parietal cortex of 60 volunteers in the Religious Orders Study. Volunteers were categorized as AD (n = 38) or controls (n = 22) based on the ABC scoring method presented in the revised guidelines for the neuropathological diagnosis of AD. Higher ELISA-determined concentrations of vascular Aβ40 and Aβ42 were found in persons with a neuropathological diagnosis of AD, in apoE4 carriers and in participants with advanced parenchymal CAA, compared to respective age-matched controls. Vascular levels of two proteins involved in Aβ clearance, ABCB1 and neprilysin, were lower in persons with AD and positively correlated with cognitive function, while being inversely correlated to vascular Aβ40. In contrast, BACE1, a protein necessary for Aβ production, was increased in individuals with AD and in apoE4 carriers, negatively correlated to cognitive function and positively correlated to Aβ40 in microvessel extracts. The present report indicates that concentrating microvessels from frozen human brain samples facilitates the quantitative biochemical analysis of cerebrovascular dysfunction in CNS disorders. Data generated overall show that microvessels extracted from individuals with parenchymal CAA-AD contained more Aβ and BACE1 and less ABCB1 and neprilysin, evidencing a pattern of dysfunction in brain microvascular cells contributing to CAA and AD pathology and symptoms.
| S-EPMC6483878 | biostudies-literature
Project description:Cerebral amyloid angiopathy (CAA) involves cerebrovascular amyloid deposition and is classified into several types according to the amyloid protein involved. Of these, sporadic amyloid β-protein (Aβ)-type CAA is most commonly found in older individuals and in patients with Alzheimer's disease (AD). Cerebrovascular Aβ deposits accompany functional and pathological changes in cerebral blood vessels (CAA-associated vasculopathies). CAA-associated vasculopathies lead to development of hemorrhagic lesions [lobar intracerebral macrohemorrhage, cortical microhemorrhage, and cortical superficial siderosis (cSS)/focal convexity subarachnoid hemorrhage (SAH)], ischemic lesions (cortical infarction and ischemic changes of the white matter), and encephalopathies that include subacute leukoencephalopathy caused by CAA-associated inflammation/angiitis. Thus, CAA is related to dementia, stroke, and encephalopathies. Recent advances in diagnostic procedures, particularly neuroimaging, have enabled us to establish a clinical diagnosis of CAA without brain biopsies. Sensitive magnetic resonance imaging (MRI) methods, such as gradient-echo T2(*) imaging and susceptibility-weighted imaging, are useful for detecting cortical microhemorrhages and cSS. Amyloid imaging with amyloid-binding positron emission tomography (PET) ligands, such as Pittsburgh Compound B, can detect CAA, although they cannot discriminate vascular from parenchymal amyloid deposits. In addition, cerebrospinal fluid markers may be useful, including levels of Aβ40 for CAA and anti-Aβ antibody for CAA-related inflammation. Moreover, cSS is closely associated with transient focal neurological episodes (TFNE). CAA-related inflammation/angiitis shares pathophysiology with amyloid-related imaging abnormalities (ARIA) induced by Aβ immunotherapies in AD patients. This article reviews CAA and CAA-related disorders with respect to their epidemiology, pathology, pathophysiology, clinical features, biomarkers, diagnosis, treatment, risk factors, and future perspectives.
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Project description:ImportanceCerebral amyloid angiopathy-related inflammation (CAA-ri), a distinct subtype of cerebral amyloid angiopathy, is characterized by an autoimmune reaction to cerebrovascular β-amyloid deposits. Outcomes and response to immunosuppressive therapy for CAA-ri are poorly understood.ObjectiveTo identify clinical, neuroimaging, laboratory, pathologic, or treatment-related associations with outcomes after an episode of CAA-ri.Design, setting, and participantsA retrospective cohort study of prospectively identified individuals who presented from July 3, 1998, to November 27, 2017, with a median follow-up of 2.7 years (interquartile range, 1.0-5.5 years). The study included 48 consecutive patients with CAA-ri meeting diagnostic criteria who had at least 1 disease episode and subsequent outcome data. No patients refused or were excluded.ExposuresPrespecified candidate variables were immunosuppressive therapies, cerebrospinal fluid pleocytosis, magnetic resonance imaging findings of recent infarcts or contrast enhancement, and histopathologic evidence of vessel wall inflammation.Main outcomes and measuresClinical improvement and worsening were defined by persistent changes in signs or symptoms, radiographic improvement by decreased subcortical foci of T2 hyperintensity or T1 enhancement, and radiographic worsening by increased subcortical T2 hyperintensity, T1 enhancement, or infarcts. Disease recurrence was defined as new-onset clinical symptoms associated with new imaging findings.ResultsThe 48 individuals in the study included 29 women and had a mean (SD) age of 68.9 (9.9) years. Results of presenting magnetic resonance imaging revealed that 10 of 29 patients with CAA-ri (34%) had T1 contrast enhancement, 30 of 32 (94%) had subcortical T2 hyperintensity (22 of 30 [73%] asymmetric), 7 of 32 (22%) had acute or subacute punctate infarcts, and 27 of 31 (87%) had microbleeds. Immunosuppressive treatments after first episodes included corticosteroids (33 [69%]), cyclophosphamide (6 [13%]), and mycophenolate (2 [4%]); 14 patients (29%) received no treatment. Clinical improvement and radiographic improvement were each more likely in individuals treated with an immunosuppressive agent than with no treatment (clinical improvement: 32 of 34 [94%] vs 7 of 14 [50%]; odds ratio, 16.0; 95% CI, 2.72-94.1; radiographic improvement: 24 of 28 [86%] vs 4 of 14 [29%]; odds ratio, 15.0; 95% CI, 3.12-72.1). Recurrence was less likely if CAA-ri was treated with any immunosuppressant agent than not (9 of 34 [26%] vs 10 of 14 [71%]; hazard ratio, 0.19; 95% CI, 0.07-0.48). When controlling for treatment, no variables were associated with outcomes aside from an association between APOE ɛ4 and radiographic improvement (odds ratio, 4.49; 95% CI, 1.11-18.2).Conclusions and relevanceThese results from a relatively large series of patients with CAA-ri support the effectiveness of immunosuppressive treatment and suggest that early treatment may both improve the initial disease course and reduce the likelihood of recurrence. These results raise the possibility that early blunting of CAA-ri and the autoimmune response may have long-term benefits for the subsequent disease course.
| S-EPMC7309570 | biostudies-literature
Project description:Amyloid-? (A?) is a peptide deposited in the brain parenchyma in Alzheimer's disease and in cerebral blood vessels, causing cerebral amyloid angiopathy (CAA). A? pathology is transmissible experimentally in animals and through medical procedures in humans, such as contaminated growth hormone or dura mater transplantation in the context of iatrogenic prion disease. Here, we present four patients who underwent neurosurgical procedures during childhood or teenage years and presented with intracerebral haemorrhage approximately three decades later, caused by severe CAA. None of these patients carried pathogenic mutations associated with early A? pathology development. In addition, we identified in the literature four patients with a history of neurosurgical intervention and subsequent development of CAA. These findings raise the possibility that A? pathology may be transmissible, as prion disease is, through neurosurgical procedures.
| S-EPMC5904220 | biostudies-literature
Project description:Patients with cerebral amyloid angiopathy (CAA) show loss of white matter connectivity and cortical thinning on MRI, primarily in posterior brain regions. Here we examined whether a potential causal relationship exists between these markers of subcortical and cortical brain injury by examining whether changes in cortical thickness progress in tandem with changes in their underlying connections. Thirty-one patients with probable CAA with brain MRI at two time points were included (follow-up time: 1.3 ± 0.4 years). Brain networks were reconstructed using diffusion MRI-based fiber tractography. Of each network node, we calculated the change in fractional anisotropy-weighted connectivity strength over time and the change in cortical thickness. The association between change in connectivity strength and cortical thickness was assessed with (hierarchical) linear regression models. Our results showed that decline in posterior network connectivity over time was strongly related to thinning of the occipital cortex (β = 0.65 (0.35-0.94), P < 0.001), but not to thinning of the other posterior or frontal cortices. However, at the level of individual network nodes, we found no association between connectivity strength and cortical thinning of the corresponding node (β = 0.009 ± 0.04, P = 0.80). Associations were independent of age, sex, and other brain MRI markers of CAA. To conclude, CAA patients with greater progressive loss of posterior white matter connectivity also have greater progression of occipital cortical thinning, but our results do not support a direct causal relationship between them. The association can be better explained by a shared underlying mechanism, which may form a potential target for future treatments. Hum Brain Mapp 38:3723-3731, 2017. © 2017 Wiley Periodicals, Inc.
| S-EPMC5662494 | biostudies-literature