scholarly journals The Role of Amyloid-β in White Matter Damage: Possible Common Pathogenetic Mechanisms in Neurodegenerative and Demyelinating Diseases

2020 ◽  
Vol 78 (1) ◽  
pp. 13-22
Author(s):  
Anna M. Pietroboni ◽  
Annalisa Colombi ◽  
Tiziana Carandini ◽  
Elio Scarpini ◽  
Daniela Galimberti ◽  
...  
Keyword(s):  
White Matter ◽  
Grey Matter ◽  
Amyloid Β ◽  
Neuronal Loss ◽  
Demyelinating Diseases ◽  
White Matter Damage ◽  
Lesion Load ◽  
Predictive Role ◽  
Disease Stages

Just as multiple sclerosis (MS) has long been primarily considered a white matter (WM) disease, Alzheimer’s disease (AD) has for decades been regarded only as a grey matter disorder. However, convergent evidences have suggested that WM abnormalities are also important components of AD, at the same extent as axonal and neuronal loss is critically involved in MS pathophysiology since early clinical stages. These observations have motivated a more thorough investigation about the possible mechanisms that could link neuroinflammation and neurodegeneration, focusing on amyloid-β (Aβ). Neuroimaging studies have found that patients with AD have widespread WM abnormalities already at the earliest disease stages and prior to the presence of Aβ plaques. Moreover, a correlation between cerebrospinal fluid (CSF) Aβ levels and WM lesion load was found. On the other hand, recent studies suggest a predictive role for CSF Aβ levels in MS, possibly due in the first instance to the reduced capacity for remyelination, consequently to a higher risk of WM damage progression, and ultimately to neuronal loss. We undertook a review of the recent findings concerning the involvement of CSF Aβ levels in the MS disease course and of the latest evidence of AD related WM abnormalities, with the aim to discuss the potential causes that may connect WM damage and amyloid pathology.

scholarly journals Exploring the laminar connectome

2021 ◽  
Author(s):  
Ittai Shamir ◽  
Omri Tomer ◽  
Ronnie Krupnik ◽  
Yaniv Assaf
Keyword(s):  
White Matter ◽  
Grey Matter ◽  
Structural Description ◽  
Mri Imaging ◽  
Healthy Human ◽  
Cortical Grey Matter ◽  
Cortical Laminar ◽  
White Matter Connectivity ◽  
Human Brains

The human connectome is the complete structural description of the network of connections and elements that form the wiring diagram of the brain. Because of the current scarcity of information regarding laminar end points of white matter tracts inside cortical grey matter, tractography remains focused on cortical partitioning into regions, while ignoring radial partitioning into laminar components. To overcome this biased representation of the cortex as a single homogenous unit, we use a recent data-derived model of cortical laminar connectivity, which has been further explored and corroborated in the macaque brain by comparison to published studies. The model integrates multimodal MRI imaging datasets regarding both white matter connectivity and grey matter laminar composition into a laminar-level connectome. In this study we model the laminar connectome of healthy human brains (N=20) and explore them via a set of neurobiologically meaningful complex network measures. Our analysis demonstrates a subdivision of network hubs that appear in the standard connectome into each individual component of the laminar connectome, giving a fresh look into the role of laminar components in cortical connectivity and offering new prospects in the fields of both structural and functional connectivity.

scholarly journals A higher proportion of ermin-immunopositive oligodendrocytes in areas of remyelination

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256155
Author(s):  
Intakhar Ahmad ◽  
Stig Wergeland ◽  
Eystein Oveland ◽  
Lars Bø
Keyword(s):  
Multiple Sclerosis ◽  
White Matter ◽  
Corpus Callosum ◽  
Mouse Model ◽  
Grey Matter ◽  
Early Stage ◽  
Relative Proportion ◽  
Normal Appearing White Matter ◽  
The Brain

Incomplete remyelination is frequent in multiple sclerosis (MS)-lesions, but there is no established marker for recent remyelination. We investigated the role of the oligodendrocyte/myelin protein ermin in de- and remyelination in the cuprizone (CPZ) mouse model, and in MS. The density of ermin+ oligodendrocytes in the brain was significantly decreased after one week of CPZ exposure (p < 0.02). The relative proportion of ermin+ cells compared to cells positive for the late-stage oligodendrocyte marker Nogo-A increased at the onset of remyelination in the corpus callosum (p < 0.02). The density of ermin-positive cells increased in the corpus callosum during the CPZ-phase of extensive remyelination (p < 0.0001). In MS, the density of ermin+ cells was higher in remyelinated lesion areas compared to non-remyelinated areas both in white- (p < 0.0001) and grey matter (p < 0.0001) and compared to normal-appearing white matter (p < 0.001). Ermin immunopositive cells in MS-lesions were not immunopositive for the early-stage oligodendrocyte markers O4 and O1, but a subpopulation was immunopositive for Nogo-A. The data suggest a relatively higher proportion of ermin immunopositivity in oligodendrocytes compared to Nogo-A indicates recent or ongoing remyelination.

scholarly journals Aberrant Oligodendrogenesis in Down Syndrome: Shift in Gliogenesis?

Cells ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1591 ◽  
Author(s):  
Laura Reiche ◽  
Patrick Küry ◽  
Peter Göttle
Keyword(s):  
Down Syndrome ◽  
White Matter ◽  
Cell Fate ◽  
Neuronal Development ◽  
Demyelinating Diseases ◽  
Therapeutic Interventions ◽  
Cell Lineages ◽  
Cns Malformations ◽  
Current Experience

Down syndrome (DS), or trisomy 21, is the most prevalent chromosomal anomaly accounting for cognitive impairment and intellectual disability (ID). Neuropathological changes of DS brains are characterized by a reduction in the number of neurons and oligodendrocytes, accompanied by hypomyelination and astrogliosis. Recent studies mainly focused on neuronal development in DS, but underestimated the role of glial cells as pathogenic players. Aberrant or impaired differentiation within the oligodendroglial lineage and altered white matter functionality are thought to contribute to central nervous system (CNS) malformations. Given that white matter, comprised of oligodendrocytes and their myelin sheaths, is vital for higher brain function, gathering knowledge about pathways and modulators challenging oligodendrogenesis and cell lineages within DS is essential. This review article discusses to what degree DS-related effects on oligodendroglial cells have been described and presents collected evidence regarding induced cell-fate switches, thereby resulting in an enhanced generation of astrocytes. Moreover, alterations in white matter formation observed in mouse and human post-mortem brains are described. Finally, the rationale for a better understanding of pathways and modulators responsible for the glial cell imbalance as a possible source for future therapeutic interventions is given based on current experience on pro-oligodendroglial treatment approaches developed for demyelinating diseases, such as multiple sclerosis.

Multi-parametric structural magnetic resonance imaging in relation to cognitive dysfunction in long-standing multiple sclerosis

2015 ◽  
Vol 22 (5) ◽  
pp. 608-619 ◽  
Author(s):  
Marita Daams ◽  
Martijn D Steenwijk ◽  
Menno M Schoonheim ◽  
Mike P Wattjes ◽  
Lisanne J Balk ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
White Matter ◽  
Cognitive Dysfunction ◽  
Cognitive Deficits ◽  
Grey Matter ◽  
White Matter Damage ◽  
Diffuse White Matter ◽  
Brain White Matter ◽  
Deep Grey Matter ◽  
Imaging Markers

Background: Cognitive deficits are common in multiple sclerosis. Most previous studies investigating the imaging substrate of cognitive deficits in multiple sclerosis included patients with relatively short disease durations and were limited to one modality/brain region. Objective: To identify the strongest neuroimaging predictors for cognitive dysfunction in a large cohort of patients with long-standing multiple sclerosis. Methods: Extensive neuropsychological testing and multimodal 3.0T MRI was performed in 202 patients with multiple sclerosis and 52 controls. Cognitive scores were compared between groups using Z-scores. Whole-brain, white matter, grey matter, deep grey matter and lesion volumes; cortical thickness, (juxta)cortical and cerebellar lesions; and extent and severity of diffuse white matter damage were measured. Stepwise linear regression was used to identify the strongest predictors for cognitive dysfunction. Results: All cognitive domains were affected in patients. Patients showed extensive atrophy, focal pathology and damage in up to 75% of the investigated white matter. Associations between imaging markers and average cognition were two times stronger in cognitively impaired patients than in cognitively preserved patients. The final model for average cognition consisted of deep grey matter DGMV volume and fractional anisotropy severity (adjusted R²=0.490; p<0.001). Conclusion: From all imaging markers, deep grey matter atrophy and diffuse white matter damage emerged as the strongest predictors for cognitive dysfunction in long-standing multiple sclerosis.

The role of white matter damage in late onset bipolar disorder

Maturitas ◽  
2011 ◽  
Vol 70 (2) ◽  
pp. 160-163 ◽  
Author(s):  
Ariadna Besga ◽  
Monica Martinez-Cengotitabengoa ◽  
Itxaso González-Ortega ◽  
Miguel Gutierrez ◽  
Sara Barbeito ◽  
...  
Keyword(s):  
Bipolar Disorder ◽  
White Matter ◽  
Late Onset ◽  
White Matter Damage

Surface-in pathology in multiple sclerosis: a new view on pathogenesis?

Brain ◽  
2021 ◽  
Author(s):  
Matteo Pardini ◽  
J William L Brown ◽  
Roberta Magliozzi ◽  
Richard Reynolds ◽  
Declan T Chard
Keyword(s):  
Multiple Sclerosis ◽  
White Matter ◽  
Grey Matter ◽  
Magnetization Transfer ◽  
Neuronal Loss ◽  
Magnetization Transfer Ratio ◽  
Supporting Evidence ◽  
Transfer Ratio ◽  
Meningeal Inflammation

Abstract While multiple sclerosis can affect any part of the CNS, it does not do so evenly. In white matter it has long been recognized that lesions tend to occur around the ventricles, and grey matter lesions mainly accrue in the outermost (subpial) cortex. In cortical grey matter, neuronal loss is greater in the outermost layers. This cortical gradient has been replicated in vivo with magnetization transfer ratio and similar gradients in grey and white matter magnetization transfer ratio are seen around the ventricles, with the most severe abnormalities abutting the ventricular surface. The cause of these gradients remains uncertain, though soluble factors released from meningeal inflammation into the CSF has the most supporting evidence. In this Update, we review this ‘surface-in’ spatial distribution of multiple sclerosis abnormalities and consider the implications for understanding pathogenic mechanisms and treatments designed to slow or stop them.

Gray matter atrophy cannot be fully explained by white matter damage in patients with MS

2020 ◽  
Vol 27 (1) ◽  
pp. 39-51 ◽  
Author(s):  
Jian Zhang ◽  
Antonio Giorgio ◽  
Claudia Vinciguerra ◽  
Maria Laura Stromillo ◽  
Marco Battaglini ◽  
...  
Keyword(s):  
White Matter ◽  
Gray Matter ◽  
Similar Data ◽  
White Matter Damage ◽  
Lesion Load ◽  
Posterior Cortex ◽  
Data Set ◽  
Close Link ◽  
Random Patterns ◽  
Normal Controls

Background: Source-based morphometry (SBM) was recently used for non-random “patterns” of gray matter (GM) atrophy or white matter (WM) microstructural damage. Objective: To assess whether and to what extent such patterns may be inter-related in MS. Methods: SBM was applied to images of GM concentration and fractional anisotropy (FA) in MS patients ( n = 41, median EDSS = 1) and normal controls (NC, n = 28). The same procedure was repeated on an independent and similar data set (39 MS patients and 13 NC). Results: We found in MS patterns of GM atrophy and reduced FA ( p < 0.05, corrected). Deep GM atrophy was mostly (70%) explained by lesion load in projection tracts and lower FA in posterior corona radiata and thalamic radiation. By contrast, sensorimotor and posterior cortex atrophy was less (50%) dependent from WM damage. All patterns correlated with EDSS ( r from −0.33 to −0.56, p < 0.03) while the only cognition-related correlation was between posterior GM atrophy pattern and processing speed ( r = 0.45, p = 0.014). Reliability analysis showed similar results. Conclusion: In relatively early MS, we found a close link between deep GM atrophy pattern and WM damage while sensorimotor and posterior cortex patterns were partially independent from WM damage and perhaps related to primary mechanisms. Patterns were clinically relevant.

scholarly journals The Role of White Matter Damage in the Risk of Periprocedural Diffusion-Weighted Lesions after Carotid Artery Stenting

2017 ◽  
Vol 7 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Paola Maggio ◽  
Claudia Altamura ◽  
Domenico Lupoi ◽  
Matteo Paolucci ◽  
Riccardo Altavilla ◽  
...  
Keyword(s):  
White Matter ◽  
Carotid Artery ◽  
Carotid Artery Stenting ◽  
Carotid Artery Disease ◽  
Restricted Diffusion ◽  
Common Finding ◽  
White Matter Damage ◽  
Lesion Load ◽  
Diffusion Weighted ◽  
Artery Disease

Background: White matter hyperintensities (WMH) are a common finding in aged individuals affected by carotid artery disease and are a risk factor for first-ever and recurrent stroke. We investigated if white matter damage increases the risk of brain microembolism during carotid artery stenting (CAS), as evaluated by the appearance of new areas of restricted diffusion on diffusion-weighted images (DWI). Methods: We evaluated 47 patients with severe internal carotid artery (ICA) stenosis undergoing CAS, comparing preprocedural clinical, ultrasound and radiological characteristics. WMH volume was computed on FLAIR images before CAS. After CAS, the DWI scan was looked over for areas of restricted diffusion (DWI lesions). A first univariate analysis was adopted to compare groups according to the occurrence of DWI lesions. Then, the variable DWI lesion was modelled by means of a logistic regression model. Results: Seventeen patients developed at least 1 DWI lesion after CAS. Compared with non-DWI, DWI patients were more commonly treated in the left ICA (p = 0.007) and had a more severe WMH damage (p = 0.027). Indeed, the risk of a DWI lesion was higher in left versus right stenosis (OR = 9.0, 95% CI 1.9-42.7, p = 0.005) and increased for each log-unit of WMH lesion load (OR = 7.05, 95% CI 1.07-46.49, p = 0.042). A WMH lesion load of at least 5.25 cm3 had a 50% probability of occurrence of a new DWI lesion. Conclusions: Treated side and preexisting white matter damage are risk conditions for brain microembolism during CAS. This should be taken into account to optimize severe carotid artery disease management.

scholarly journals The Role of White Matter in the Neural Control of Swallowing: A Systematic Review

2021 ◽  
Vol 15 ◽  
Author(s):  
Ann Alvar ◽  
Rachel Hahn Arkenberg ◽  
Bethany McGowan ◽  
Hu Cheng ◽  
Georgia A. Malandraki
Keyword(s):  
Systematic Review ◽  
White Matter ◽  
Neural Control ◽  
White Matter Lesions ◽  
Internal Capsule ◽  
Senior Author ◽  
Sufficient Evidence ◽  
Qualitative Synthesis ◽  
White Matter Damage

Background: Swallowing disorders (dysphagia) can negatively impact quality of life and health. For clinicians and researchers seeking to improve outcomes for patients with dysphagia, understanding the neural control of swallowing is critical. The role of gray matter in swallowing control has been extensively documented, but knowledge is limited regarding the contributions of white matter. Our aim was to identify, evaluate, and summarize the populations, methods, and results of published articles describing the role of white matter in neural control of swallowing.Methods: We completed a systematic review with a multi-engine search following PRISMA-P 2015 standards. Two authors screened articles and completed blind full-text review and quality assessments using an adapted U.S. National Institute of Health's Quality Assessment. The senior author resolved any disagreements. Qualitative synthesis of evidence was completed.Results: The search yielded 105 non-duplicate articles, twenty-two of which met inclusion criteria. Twenty were rated as Good (5/22; 23%) or Fair (15/22; 68%) quality. Stroke was the most represented diagnosis (n = 20; 91%). All studies were observational, and half were retrospective cohort design. The majority of studies (13/22; 59%) quantified white matter damage with lesion-based methods, whereas 7/22 (32%) described intrinsic characteristics of white matter using methods like fractional anisotropy. Fifteen studies (68%) used instrumental methods for swallowing evaluations. White matter areas commonly implicated in swallowing control included the pyramidal tract, internal capsule, corona radiata, superior longitudinal fasciculus, external capsule, and corpus callosum. Additional noteworthy themes included: severity of white matter damage is related to dysphagia severity; bilateral white matter lesions appear particularly disruptive to swallowing; and white matter adaptation can facilitate dysphagia recovery. Gaps in the literature included limited sample size and populations, lack of in-depth evaluations, and issues with research design.Conclusion: Although traditionally understudied, there is sufficient evidence to conclude that white matter is critical in the neural control of swallowing. The reviewed studies indicated that white matter damage can be directly tied to swallowing deficits, and several white matter structures were implicated across studies. Further well-designed interdisciplinary research is needed to understand white matter's role in neural control of normal swallowing and in dysphagia recovery and rehabilitation.

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