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Hase Y, Jobson D, Cheong J, Gotama K, Maffei L, Hase M, Hamdan A, Ding R, Polivkoski T, Horsburgh K, Kalaria RN. Hippocampal capillary pericytes in post-stroke and vascular dementias and Alzheimer's disease and experimental chronic cerebral hypoperfusion. Acta Neuropathol Commun 2024; 12:29. [PMID: 38360798 PMCID: PMC10870440 DOI: 10.1186/s40478-024-01737-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 02/01/2024] [Indexed: 02/17/2024] Open
Abstract
Neurovascular unit mural cells called 'pericytes' maintain the blood-brain barrier and local cerebral blood flow. Pathological changes in the hippocampus predispose to cognitive impairment and dementia. The role of hippocampal pericytes in dementia is largely unknown. We investigated hippocampal pericytes in 90 post-mortem brains from post-stroke dementia (PSD), vascular dementia (VaD), Alzheimer's disease (AD), and AD-VaD (Mixed) subjects, and post-stroke non-demented survivors as well as similar age controls. We used collagen IV immunohistochemistry to determine pericyte densities and a mouse model of VaD to validate the effects of chronic cerebral hypoperfusion. Despite increased trends in hippocampal microvascular densities across all dementias, mean pericyte densities were reduced by ~25-40% in PSD, VaD and AD subjects compared to those in controls, which calculated to 14.1 ± 0.7 per mm capillary length, specifically in the cornu ammonis (CA) 1 region (P = 0.01). In mice with chronic bilateral carotid artery occlusion, hippocampal pericyte loss was ~60% relative to controls (P < 0.001). Pericyte densities were correlated with CA1 volumes (r = 0.54, P = 0.006) but not in any other sub-region. However, mice subjected to the full-time environmental enrichment (EE) paradigm showed remarkable attenuation of hippocampal CA1 pericyte loss in tandem with CA1 atrophy. Our results suggest loss of hippocampal microvascular pericytes across common dementias is explained by a vascular aetiology, whilst the EE paradigm offers significant protection.
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Affiliation(s)
- Yoshiki Hase
- Neurovascular Research Group, Translational and Clinical Research Institute, Campus for Ageing & Vitality, Newcastle University, NE4 5PL, Newcastle upon Tyne, UK
| | - Dan Jobson
- Neurovascular Research Group, Translational and Clinical Research Institute, Campus for Ageing & Vitality, Newcastle University, NE4 5PL, Newcastle upon Tyne, UK
| | - Jeremy Cheong
- Neurovascular Research Group, Translational and Clinical Research Institute, Campus for Ageing & Vitality, Newcastle University, NE4 5PL, Newcastle upon Tyne, UK
| | - Kelvin Gotama
- Neurovascular Research Group, Translational and Clinical Research Institute, Campus for Ageing & Vitality, Newcastle University, NE4 5PL, Newcastle upon Tyne, UK
| | - Luciana Maffei
- Neurovascular Research Group, Translational and Clinical Research Institute, Campus for Ageing & Vitality, Newcastle University, NE4 5PL, Newcastle upon Tyne, UK
| | - Mai Hase
- Neurovascular Research Group, Translational and Clinical Research Institute, Campus for Ageing & Vitality, Newcastle University, NE4 5PL, Newcastle upon Tyne, UK
| | - Alhafidz Hamdan
- Neurovascular Research Group, Translational and Clinical Research Institute, Campus for Ageing & Vitality, Newcastle University, NE4 5PL, Newcastle upon Tyne, UK
| | - Ren Ding
- Neurovascular Research Group, Translational and Clinical Research Institute, Campus for Ageing & Vitality, Newcastle University, NE4 5PL, Newcastle upon Tyne, UK
| | - Tuomo Polivkoski
- Neurovascular Research Group, Translational and Clinical Research Institute, Campus for Ageing & Vitality, Newcastle University, NE4 5PL, Newcastle upon Tyne, UK
| | - Karen Horsburgh
- Centre for Neuroregeneration, University of Edinburgh, Little France Crescent, Edinburgh, UK
| | - Raj N Kalaria
- Neurovascular Research Group, Translational and Clinical Research Institute, Campus for Ageing & Vitality, Newcastle University, NE4 5PL, Newcastle upon Tyne, UK.
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van Dinther M, Hooghiemstra AM, Bron EE, Versteeg A, Leeuwis AE, Kalay T, Moonen JE, Kuipers S, Backes WH, Jansen JFA, van Osch MJP, Biessels G, Staals J, van Oostenbrugge RJ. Lower cerebral blood flow predicts cognitive decline in patients with vascular cognitive impairment. Alzheimers Dement 2024; 20:136-144. [PMID: 37491840 PMCID: PMC10917014 DOI: 10.1002/alz.13408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 06/26/2023] [Accepted: 07/03/2023] [Indexed: 07/27/2023]
Abstract
INTRODUCTION Chronic cerebral hypoperfusion is one of the assumed pathophysiological mechanisms underlying vascular cognitive impairment (VCI). We investigated the association between baseline cerebral blood flow (CBF) and cognitive decline after 2 years in patients with VCI and reference participants. METHODS One hundred eighty-one participants (mean age 66.3 ± 7.4 years, 43.6% women) underwent arterial spin labeling (ASL) magnetic resonance imaging (MRI) and neuropsychological assessment at baseline and at 2-year follow-up. We determined the association between baseline global and lobar CBF and cognitive decline with multivariable regression analysis. RESULTS Lower global CBF at baseline was associated with more global cognitive decline in VCI and reference participants. This association was most profound in the domain of attention/psychomotor speed. Lower temporal and frontal CBF at baseline were associated with more cognitive decline in memory. DISCUSSION Our study supports the role of hypoperfusion in the pathophysiological and clinical progression of VCI. HIGHLIGHTS Impaired cerebral blood flow (CBF) at baseline is associated with faster cognitive decline in VCI and normal aging. Our results suggest that low CBF precedes and contributes to the development of vascular cognitive impairment. CBF determined by ASL might be used as a biomarker to monitor disease progression or treatment responses in VCI.
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Affiliation(s)
- Maud van Dinther
- Department of NeurologyMaastricht University Medical CenterMaastrichtThe Netherlands
| | - Astrid M. Hooghiemstra
- Alzheimer Center Amsterdam, Department of Neurology, Amsterdam Neuroscience, Amsterdam UMCVrije Universiteit AmsterdamAmsterdamThe Netherlands
| | - Esther E. Bron
- Department of Radiology & Nuclear MedicineErasmus MC—University Medical Center RotterdamRotterdamThe Netherlands
| | - Adriaan Versteeg
- Department of Radiology & Nuclear MedicineErasmus MC—University Medical Center RotterdamRotterdamThe Netherlands
| | - Anna E. Leeuwis
- Alzheimer Center Amsterdam, Department of Neurology, Amsterdam Neuroscience, Amsterdam UMCVrije Universiteit AmsterdamAmsterdamThe Netherlands
- Department of Old Age PsychiatryGGZ inGeestAmsterdamThe Netherlands
| | - Tugba Kalay
- Department of NeurologySt. Antonius ZiekenhuisNieuwegeinThe Netherlands
| | - Justine E. Moonen
- Alzheimer Center Amsterdam, Department of Neurology, Amsterdam Neuroscience, Amsterdam UMCVrije Universiteit AmsterdamAmsterdamThe Netherlands
| | - Sanne Kuipers
- Department of NeurologyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Walter H. Backes
- Department of Radiology and Nuclear MedicineMaastricht University Medical CenterMaastrichtThe Netherlands
| | - Jacobus F. A. Jansen
- Department of Radiology and Nuclear MedicineMaastricht University Medical CenterMaastrichtThe Netherlands
| | - Mathias J. P. van Osch
- C.J. Gorter MRI Center, Department of RadiologyLeiden University Medical CenterLeidenThe Netherlands
| | - Geert‐Jan Biessels
- Department of NeurologyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Julie Staals
- Department of NeurologyMaastricht University Medical CenterMaastrichtThe Netherlands
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Kandiah N. Cognitive Outcomes Poststroke: A Need for Better Insights into Mechanisms. Brain Connect 2023; 13:438-440. [PMID: 37782227 DOI: 10.1089/brain.2023.29054.editorial] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/03/2023] Open
Affiliation(s)
- Nagaendran Kandiah
- Associate Professor of Neuroscience and Mental Health, Nanyang Technological University, Singapore, Singapore
- Director, Dementia Research Centre (Singapore), LKC-Imperial Medical School, Nanyang Technological University, Singapore, Singapore
- Consultant Neurologist, National University Hospital, Singapore, Singapore
- Clinician Scientist, National Medical Research Council, Singapore, Singapore
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Swinford CG, Risacher SL, Wu YC, Apostolova LG, Gao S, Bice PJ, Saykin AJ. Altered cerebral blood flow in older adults with Alzheimer's disease: a systematic review. Brain Imaging Behav 2023; 17:223-256. [PMID: 36484922 PMCID: PMC10117447 DOI: 10.1007/s11682-022-00750-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 09/26/2022] [Accepted: 11/20/2022] [Indexed: 12/13/2022]
Abstract
The prevalence of Alzheimer's disease is projected to reach 13 million in the U.S. by 2050. Although major efforts have been made to avoid this outcome, so far there are no treatments that can stop or reverse the progressive cognitive decline that defines Alzheimer's disease. The utilization of preventative treatment before significant cognitive decline has occurred may ultimately be the solution, necessitating a reliable biomarker of preclinical/prodromal disease stages to determine which older adults are most at risk. Quantitative cerebral blood flow is a promising potential early biomarker for Alzheimer's disease, but the spatiotemporal patterns of altered cerebral blood flow in Alzheimer's disease are not fully understood. The current systematic review compiles the findings of 81 original studies that compared resting gray matter cerebral blood flow in older adults with mild cognitive impairment or Alzheimer's disease and that of cognitively normal older adults and/or assessed the relationship between cerebral blood flow and objective cognitive function. Individuals with Alzheimer's disease had relatively decreased cerebral blood flow in all brain regions investigated, especially the temporoparietal and posterior cingulate, while individuals with mild cognitive impairment had consistent results of decreased cerebral blood flow in the posterior cingulate but more mixed results in other regions, especially the frontal lobe. Most papers reported a positive correlation between regional cerebral blood flow and cognitive function. This review highlights the need for more studies assessing cerebral blood flow changes both spatially and temporally over the course of Alzheimer's disease, as well as the importance of including potential confounding factors in these analyses.
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Affiliation(s)
- Cecily G Swinford
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 355 W 16th St. IU Neuroscience Center, GH 4101, 46202, Indianapolis, IN, USA
- Indiana Alzheimer's Disease Research Center, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Shannon L Risacher
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 355 W 16th St. IU Neuroscience Center, GH 4101, 46202, Indianapolis, IN, USA
- Indiana Alzheimer's Disease Research Center, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Yu-Chien Wu
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 355 W 16th St. IU Neuroscience Center, GH 4101, 46202, Indianapolis, IN, USA
- Indiana Alzheimer's Disease Research Center, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Liana G Apostolova
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 355 W 16th St. IU Neuroscience Center, GH 4101, 46202, Indianapolis, IN, USA
- Indiana Alzheimer's Disease Research Center, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Neurology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Sujuan Gao
- Indiana Alzheimer's Disease Research Center, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Biostatistics and Health Data Science, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Paula J Bice
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 355 W 16th St. IU Neuroscience Center, GH 4101, 46202, Indianapolis, IN, USA
- Indiana Alzheimer's Disease Research Center, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Andrew J Saykin
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, 355 W 16th St. IU Neuroscience Center, GH 4101, 46202, Indianapolis, IN, USA.
- Indiana Alzheimer's Disease Research Center, Indiana University School of Medicine, Indianapolis, IN, USA.
- Department of Neurology, Indiana University School of Medicine, Indianapolis, IN, USA.
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Huang D, Guo Y, Guan X, Pan L, Zhu Z, Chen Z, Dijkhuizen RM, Duering M, Yu F, Boltze J, Li P. Recent advances in arterial spin labeling perfusion MRI in patients with vascular cognitive impairment. J Cereb Blood Flow Metab 2023; 43:173-184. [PMID: 36284489 PMCID: PMC9903225 DOI: 10.1177/0271678x221135353] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 08/01/2022] [Accepted: 09/21/2022] [Indexed: 01/24/2023]
Abstract
Cognitive impairment (CI) is a major health concern in aging populations. It impairs patients' independent life and may progress to dementia. Vascular cognitive impairment (VCI) encompasses all cerebrovascular pathologies that contribute to cognitive impairment (CI). Moreover, the majority of CI subtypes involve various aspects of vascular dysfunction. Recent research highlights the critical role of reduced cerebral blood flow (CBF) in the progress of VCI, and the detection of altered CBF may help to detect or even predict the onset of VCI. Arterial spin labeling (ASL) is a non-invasive, non-ionizing perfusion MRI technique for assessing CBF qualitatively and quantitatively. Recent methodological advances enabling improved signal-to-noise ratio (SNR) and data acquisition have led to an increase in the use of ASL to assess CBF in VCI patients. Combined with other imaging modalities and biomarkers, ASL has great potential for identifying early VCI and guiding prediction and prevention strategies. This review focuses on recent advances in ASL-based perfusion MRI for identifying patients at high risk of VCI.
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Affiliation(s)
- Dan Huang
- Department of Anesthesiology, Clinical Research Center, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yunlu Guo
- Department of Anesthesiology, Clinical Research Center, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaoyu Guan
- Department of Anesthesiology, Clinical Research Center, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lijun Pan
- Department of Radiology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ziyu Zhu
- Department of Anesthesiology, Clinical Research Center, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zeng’ai Chen
- Department of Radiology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Rick M Dijkhuizen
- Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht and Utrecht University, Utrecht, the Netherlands
| | - Marco Duering
- Institute for Stroke and Dementia Research, University Hospital, LMU Munich, Germany
- Medical Image Analysis Center (MIAC) and qbig, Department of Biomedical Engineering, University of Basel, Basel, Switzerland
| | - Fang Yu
- Department of Anesthesiology, Westchester Medical Center, New York Medical College, NY, USA
| | - Johannes Boltze
- School of Life Sciences, University of Warwick, Coventry, UK
| | - Peiying Li
- Department of Anesthesiology, Clinical Research Center, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Effects of Physical Exercise Training on Cerebral Blood Flow Measurements: A Systematic Review of Human Intervention Studies. Int J Sport Nutr Exerc Metab 2023; 33:47-59. [PMID: 36170974 DOI: 10.1123/ijsnem.2022-0085] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 07/14/2022] [Accepted: 08/12/2022] [Indexed: 12/27/2022]
Abstract
The aim of this systematic review was to examine the effects of physical exercise training on cerebral blood flow (CBF), which is a physiological marker of cerebrovascular function. Relationships between training-induced effects on CBF with changes in cognitive performance were also discussed. A systematic search was performed up to July 2022. Forty-five intervention studies with experimental, quasi-experimental, or pre-post designs were included. Sixteen studies (median duration: 14 weeks) investigated effects of physical exercise training on CBF markers using magnetic resonance imaging, 20 studies (median duration: 14 weeks) used transcranial Doppler ultrasound, and eight studies (median duration: 8 weeks) used near-infrared spectroscopy. Studies using magnetic resonance imaging observed consistent increases in CBF in the anterior cingulate cortex and hippocampus, but not in whole-brain CBF. Effects on resting CBF-measured with transcranial Doppler ultrasound and near-infrared spectroscopy-were variable, while middle cerebral artery blood flow velocity increased in some studies following exercise or hypercapnic stimuli. Interestingly, concomitant changes in physical fitness and regional CBF were observed, while a relation between training-induced effects on CBF and cognitive performance was evident. In conclusion, exercise training improved cerebrovascular function because regional CBF was changed. Studies are however still needed to establish whether exercise-induced improvements in CBF are sustained over longer periods of time and underlie the observed beneficial effects on cognitive performance.
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7
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The impact of cerebral vasomotor reactivity on cerebrovascular diseases and cognitive impairment. J Neural Transm (Vienna) 2022; 129:1321-1330. [PMID: 36205784 PMCID: PMC9550758 DOI: 10.1007/s00702-022-02546-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 09/19/2022] [Indexed: 11/10/2022]
Abstract
The regulation of cerebral blood flow (CBF) is a complex and tightly controlled function ensuring delivery of oxygen and nutrients and removal of metabolic wastes from brain tissue. Cerebral vasoreactivity (CVR) refers to the ability of the nervous system to regulate CBF according to metabolic demands or changes in the microenvironment. This can be assessed through a variety of nuclear medicine and imaging techniques and protocols. Several studies have investigated the association of CVR with physiological and pathological conditions, with particular reference to the relationship with cognitive impairment and cerebrovascular disorders (CVD). A better understanding of the interaction between CVR and cognitive dysfunction in chronic and particularly acute CVD could help improving treatment and rehabilitation strategies in these patients. In this paper, we reviewed current knowledge on CVR alterations in the context of acute and chronic CVD and cognitive dysfunction. Alterations in CVR and hemodynamics have been described in patients with both neurodegenerative and vascular cognitive impairment, and the severity of these alterations seems to correlate with CVR derailment. Furthermore, an increased risk of cognitive impairment progression has been associated with alterations in CVR parameters and hemodynamics. Few studies have investigated these associations in acute cerebrovascular disorders and the results are inconsistent; thus, further research on this topic is encouraged.
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8
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Tu MC, Chung HW, Hsu YH, Yang JJ, Wu WC. Stage-Dependent Cerebral Blood Flow and Leukoaraiosis Couplings in Subcortical Ischemic Vascular Disease and Alzheimer's Disease. J Alzheimers Dis 2022; 86:729-739. [PMID: 35124651 PMCID: PMC9028753 DOI: 10.3233/jad-215405] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Background: Alzheimer’s disease (AD) and subcortical ischemic vascular disease (SIVD) have both been associated with white matter hyperintensities (WMHs) and altered cerebral blood flow (CBF) although the etiology of AD is still unclear. Objective: To test the hypothesis that CBF and WMHs have differential effects on cognition and that the relationship between CBF and WMHs changes with the subtypes and stages of dementia. Methods: Forty-two patients with SIVD, 50 patients with clinically-diagnosed AD, and 30 cognitively-normal subjects were included. Based on the Clinical Dementia Rating (CDR), the patients were dichotomized into early-stage (CDR = 0.5) and late-stage (CDR = 1 or 2) groups. CBF and WMH metrics were derived from magnetic resonance imaging and correlated with cognition. Results: Hierarchical linear regression revealed that CBF metrics had distinct contribution to global cognition, memory, and attention, whereas WMH metrics had distinct contribution to executive function (all p < 0.05). In SIVD, the WMHs in frontotemporal areas correlated with the CBF in bilateral thalami at the early stage; the correlation then became between the WMHs in basal ganglia and the CBF in frontotemporal areas at the late stage. A similar corticosubcortical coupling was observed in AD but involved fewer areas. Conclusion: A stage-dependent coupling between CBF and WMHs was identified in AD and SIVD, where the extent of cortical WMHs correlated with subcortical CBF for CDR = 0.5, whereas the extent of subcortical WMHs correlated with cortical CBF for CDR = 1–2.
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Affiliation(s)
- Min-Chien Tu
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan.,Department of Neurology, Taichung Tzu Chi Hospital, Taichung, Taiwan.,Department of Neurology, Tzu Chi University, Hualien, Taiwan
| | - Hsiao-Wen Chung
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan
| | - Yen-Hsuan Hsu
- Department of Psychology, National Chung Cheng University, Chiayi, Taiwan.,Center for Innovative Research on Aging Society, National Chung Cheng University, Chiayi, Taiwan
| | - Jir-Jei Yang
- Department of Radiology, Taichung Tzu Chi Hospital, Taichung, Taiwan
| | - Wen-Chau Wu
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan.,Institute of Medical Device and Imaging, National Taiwan University, Taipei, Taiwan
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9
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Xie J, Cheng Z, Gu L, Wu B, Zhang G, Shiu W, Chen R, Wang Z, Liu C, Tu J, Cai X, Liu J, Zhang Z. Evaluation of cerebrovascular hemodynamics in vascular dementia patients with a new individual computational fluid dynamics algorithm. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 213:106497. [PMID: 34749243 DOI: 10.1016/j.cmpb.2021.106497] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 10/19/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Cerebral hemodynamic disorders are involved in the occurrence and progression of vascular dementia (VaD), but the methods to detect hemodynamics remainmultifarious and uncertain nowadays. We aim to exploit a computational fluid dynamics (CFD) approach by static and dynamic parameters, which can be used to detect individual cerebrovascular hemodynamics quantitatively. METHODS A patient-specific CFD model was constructed with geometrical arteries on the magnetic resonance angiography (MRA) and hemodynamic parameters on ultrasound Doppler, by which, the structural and simulated hemodynamic indexes could be obtained, mainly including the cerebral arterial volume (CAV), the number of visible arterial outlets, the total cerebral blood flow (tCBF) index and the total cerebrovascular resistance (tCVR) index. The hemodynamics were detected in subcortical vascular dementia (SVaD) patients (n = 38) and cognitive normal controls (CNCs; n = 40). RESULTS Compared with CNCs, the SVaD patients had reduced outlets, CAV and tCBF index (all P ≤ 0.001), increased volume of white matter hyperintensity (WMH) and tCVR index (both P ≤ 0.01). The fewer outlets (OR = 0.77), higher Hachinski ischemic score (HIS) (OR = 3.65), increased tCVR index (OR = 1.98) and volume of WMH (OR = 1.12) were independently associated with SVaD. All hemodynamic parameters could differentiate the SVaD patinets and CNCs, especially the composite index calculated by outlets, tCVR index and HIS (AUC = 0.943). Fewer outlets and more WMH increased the odds of SVaD, which were partly mediated by the tCBF index (14.4% and 13.0%, respectively). CONCLUSION The reduced outlets, higher HIS and tCVR index may be independent risk factors for the SVaD, and a combination of these indexes can differentiate SVaD patients and CNCs reliably. The tCBF index potentially mediates the relationships between hemodynamic indexes and SVaD. Although all simulated indexes only represented the true hemodynamics indirectly, this CFD model can provide patient-specific hemodynamic alterations non-invasively and conveniently.
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Affiliation(s)
- Jian Xie
- Department of Neurology, Key Laboratory of Developmental Genes and Human Disease, Affiliated ZhongDa Hospital, School of Medicine, Institution of Neuropsychiatry, Southeast University, Nanjing, Jiangsu 210009, China
| | - Zaiheng Cheng
- Laboratory for Engineering and Scientific Computing, Institute of Advanced Computing and Digital Engineering, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong 518055, China
| | - Lihua Gu
- Department of Neurology, Key Laboratory of Developmental Genes and Human Disease, Affiliated ZhongDa Hospital, School of Medicine, Institution of Neuropsychiatry, Southeast University, Nanjing, Jiangsu 210009, China
| | - Bokai Wu
- Laboratory for Engineering and Scientific Computing, Institute of Advanced Computing and Digital Engineering, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong 518055, China
| | - Gaojia Zhang
- Department of Neurology, Key Laboratory of Developmental Genes and Human Disease, Affiliated ZhongDa Hospital, School of Medicine, Institution of Neuropsychiatry, Southeast University, Nanjing, Jiangsu 210009, China
| | - Wenshin Shiu
- Laboratory for Engineering and Scientific Computing, Institute of Advanced Computing and Digital Engineering, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong 518055, China
| | - Rongliang Chen
- Laboratory for Engineering and Scientific Computing, Institute of Advanced Computing and Digital Engineering, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong 518055, China
| | - Zan Wang
- Department of Neurology, Key Laboratory of Developmental Genes and Human Disease, Affiliated ZhongDa Hospital, School of Medicine, Institution of Neuropsychiatry, Southeast University, Nanjing, Jiangsu 210009, China
| | - Chang Liu
- Laboratory for Engineering and Scientific Computing, Institute of Advanced Computing and Digital Engineering, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong 518055, China
| | - Jie Tu
- The Brain Cognition and Brain Disease institute of Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong 518055, China
| | - Xiaochuan Cai
- Department of Computer Science, University of Colorado Boulder, United States
| | - Jia Liu
- Laboratory for Engineering and Scientific Computing, Institute of Advanced Computing and Digital Engineering, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong 518055, China.
| | - Zhijun Zhang
- Department of Neurology, Key Laboratory of Developmental Genes and Human Disease, Affiliated ZhongDa Hospital, School of Medicine, Institution of Neuropsychiatry, Southeast University, Nanjing, Jiangsu 210009, China; The Brain Cognition and Brain Disease institute of Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong 518055, China; Research Center for Brain Health, Pazhou Lab, Guangzhou, Guangdong 510330, China.
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10
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Vinciguerra L, Lanza G, Puglisi V, Fisicaro F, Pennisi M, Bella R, Cantone M. Update on the Neurobiology of Vascular Cognitive Impairment: From Lab to Clinic. Int J Mol Sci 2020; 21:E2977. [PMID: 32340195 PMCID: PMC7215552 DOI: 10.3390/ijms21082977] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 04/20/2020] [Accepted: 04/21/2020] [Indexed: 02/07/2023] Open
Abstract
In the last years, there has been a significant growth in the literature exploring the pathophysiology of vascular cognitive impairment (VCI). As an "umbrella term" encompassing any degree of vascular-related cognitive decline, VCI is deemed to be the most common cognitive disorder in the elderly, with a significant impact on social and healthcare expenses. Interestingly, some of the molecular, biochemical, and electrophysiological abnormalities detected in VCI seem to correlate with disease process and progression, eventually promoting an adaptive plasticity in some patients and a maladaptive, dysfunctional response in others. However, the exact relationships between vascular lesion, cognition, and neuroplasticity are not completely understood. Recent findings point out also the possibility to identify a panel of markers able to predict cognitive deterioration in the so-called "brain at risk" for vascular or mixed dementia. This will be of pivotal importance when designing trials of disease-modifying drugs or non-pharmacological approaches, including non-invasive neuromodulatory techniques. Taken together, these advances could make VCI a potentially preventable cause of both vascular and degenerative dementia in late life. This review provides a timely update on the recent serological, cerebrospinal fluid, histopathological, imaging, and neurophysiological studies on this "cutting-edge" topic, including the limitations, future perspectives and translational implications in the diagnosis and management of VCI patients.
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Affiliation(s)
- Luisa Vinciguerra
- Department of Neurology and Stroke Unit, ASST Cremona, 26100 Cremona, Italy; (L.V.); (V.P.)
| | - Giuseppe Lanza
- Department of Surgery and Medical-Surgical Specialties, University of Catania, 95123 Catania, Italy
- Department of Neurology IC, Oasi Research Institute – IRCCS, 94018 Troina, Italy
| | - Valentina Puglisi
- Department of Neurology and Stroke Unit, ASST Cremona, 26100 Cremona, Italy; (L.V.); (V.P.)
| | - Francesco Fisicaro
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy; (F.F.); (M.P.)
| | - Manuela Pennisi
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy; (F.F.); (M.P.)
| | - Rita Bella
- Department of Medical and Surgical Sciences and Advanced Technologies, University of Catania, 95123 Catania, Italy;
| | - Mariagiovanna Cantone
- Department of Neurology, Sant’Elia Hospital, ASP Caltanissetta, 93100 Caltanissetta, Italy;
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11
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Update on the Neurobiology of Vascular Cognitive Impairment: From Lab to Clinic. Int J Mol Sci 2020. [PMID: 32340195 DOI: 10.3390/ijms21082977.] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
In the last years, there has been a significant growth in the literature exploring the pathophysiology of vascular cognitive impairment (VCI). As an "umbrella term" encompassing any degree of vascular-related cognitive decline, VCI is deemed to be the most common cognitive disorder in the elderly, with a significant impact on social and healthcare expenses. Interestingly, some of the molecular, biochemical, and electrophysiological abnormalities detected in VCI seem to correlate with disease process and progression, eventually promoting an adaptive plasticity in some patients and a maladaptive, dysfunctional response in others. However, the exact relationships between vascular lesion, cognition, and neuroplasticity are not completely understood. Recent findings point out also the possibility to identify a panel of markers able to predict cognitive deterioration in the so-called "brain at risk" for vascular or mixed dementia. This will be of pivotal importance when designing trials of disease-modifying drugs or non-pharmacological approaches, including non-invasive neuromodulatory techniques. Taken together, these advances could make VCI a potentially preventable cause of both vascular and degenerative dementia in late life. This review provides a timely update on the recent serological, cerebrospinal fluid, histopathological, imaging, and neurophysiological studies on this "cutting-edge" topic, including the limitations, future perspectives and translational implications in the diagnosis and management of VCI patients.
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Luckett P, Paul RH, Navid J, Cooley SA, Wisch JK, Boerwinkle AH, Tomov D, Ances BM. Deep Learning Analysis of Cerebral Blood Flow to Identify Cognitive Impairment and Frailty in Persons Living With HIV. J Acquir Immune Defic Syndr 2019; 82:496-502. [PMID: 31714429 PMCID: PMC6857844 DOI: 10.1097/qai.0000000000002181] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND Deep learning algorithms of cerebral blood flow were used to classify cognitive impairment and frailty in people living with HIV (PLWH). Feature extraction techniques identified brain regions that were the strongest predictors. SETTING Virologically suppressed (<50 copies/mL) PLWH (n = 125) on combination antiretroviral therapy were enrolled. Participants averaged 51.4 (11.4) years of age and 13.7 (2.8) years of education. Participants were administered a neuropsychological battery, assessed for frailty, and completed structural neuroimaging. METHODS Deep neural network (DNN) models were trained to classify PLWH as cognitively unimpaired or impaired based on neuropsychological tests (Hopkins Verbal Learning Test-Revised and Brief Visuospatial Memory Test-Revised, Trail making, Letter-Number Sequencing, Verbal Fluency, and Color Word Interference), as well as frail, prefrail, or nonfrail based on the Fried phenotype criteria (at least 3 of the following 5: weight loss, physical inactivity, exhaustion, grip strength, walking time). RESULTS DNNs classified individuals with cognitive impairment in the learning, memory, and executive domains with 82%-86% accuracy (0.81-0.87 AUC). Our model classified nonfrail, prefrail, and frail PLWH with 75% accuracy. The strongest predictors of cognitive impairment were cortical (parietal, occipital, and temporal) and subcortical (amygdala, caudate, and hippocampus) regions, whereas the strongest predictors of frailty were subcortical (amygdala, caudate, hippocampus, thalamus, pallidum, and cerebellum). CONCLUSIONS DNN models achieved high accuracy in classifying cognitive impairment and frailty status in PLWH. Feature selection algorithms identified predictive regions in each domain and identified overlapping regions between cognitive impairment and frailty. Our results suggest frailty in HIV is primarily subcortical, whereas cognitive impairment in HIV involves subcortical and cortical brain regions.
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Affiliation(s)
- Patrick Luckett
- Department of Neurology, Washington University School of Medicine, St. Louis, MI
| | - Robert H Paul
- Department of Psychological Sciences, University of Missouri Saint Louis, St. Louis, MI
| | - Jaimie Navid
- Department of Neurology, Washington University School of Medicine, St. Louis, MI
| | - Sarah A Cooley
- Department of Neurology, Washington University School of Medicine, St. Louis, MI
| | - Julie K Wisch
- Department of Neurology, Washington University School of Medicine, St. Louis, MI
| | - Anna H Boerwinkle
- Department of Neurology, Washington University School of Medicine, St. Louis, MI
| | - Dimitre Tomov
- Department of Neurology, Washington University School of Medicine, St. Louis, MI
| | - Beau M Ances
- Department of Neurology, Washington University School of Medicine, St. Louis, MI
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13
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Li Y, Cui Z, Liao Q, Dong H, Zhang J, Shen W, Zhou W. Support vector machine-based multivariate pattern classification of methamphetamine dependence using arterial spin labeling. Addict Biol 2019; 24:1254-1262. [PMID: 30623517 DOI: 10.1111/adb.12705] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 11/14/2018] [Accepted: 11/17/2018] [Indexed: 01/15/2023]
Abstract
Arterial spin labeling (ASL) magnetic resonance imaging has been widely applied to identify cerebral blood flow (CBF) abnormalities in a number of brain disorders. To evaluate its significance in detecting methamphetamine (MA) dependence, this study used a multivariate pattern classification algorithm, ie, a support vector machine (SVM), to construct classifiers for discriminating MA-dependent subjects from normal controls. Forty-five MA-dependent subjects, 45 normal controls, and 36 heroin-dependent subjects were enrolled. Classifiers trained with ASL-CBF data from the left or right cerebrum showed significant hemispheric asymmetry in their cross-validated prediction performance (P < 0.001 for accuracy, sensitivity, specificity, kappa, and area under the curve [AUC] of the receiver operating characteristics [ROC] curve). A classifier trained with ASL-CBF data from all cerebral regions (bilateral hemispheres and corpus callosum) was able to differentiate MA-dependent subjects from normal controls with a cross-validated prediction accuracy, sensitivity, specificity, kappa, and AUC of 89%, 94%, 84%, 0.78, and 0.95, respectively. The discrimination map extracted from this classifier covered multiple brain circuits that either constitute a network related to drug abuse and addiction or could be impaired in MA-dependence. The cerebral regions contribute most to classification include occipital lobe, insular cortex, postcentral gyrus, corpus callosum, and inferior frontal cortex. This classifier was also specific to MA-dependence rather than substance use disorders in general (ie, 55.56% accuracy for heroin dependence). These results support the future utilization of ASL with an SVM-based classifier for the diagnosis of MA-dependence and could help improve the understanding of MA-related neuropathology.
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Affiliation(s)
- Yadi Li
- Department of Radiology, Ningbo Medical Center Lihuili HospitalNingbo University Ningbo China
| | - Zaixu Cui
- Department of Psychiatry, Perelman School of MedicineUniversity of Pennsylvania Philadelphia Pennsylvania USA
| | - Qi Liao
- Department of Preventative Medicine, Zhejiang Provincial Key Laboratory of PathophysiologyMedical School of Ningbo University Ningbo China
| | - Haibo Dong
- Department of Radiology, Ningbo Medical Center Lihuili HospitalNingbo University Ningbo China
| | - Jianbing Zhang
- Laboratory of Behavioral Neuroscience, Ningbo Addiction Research and Treatment Center Ningbo China
| | - Wenwen Shen
- Laboratory of Behavioral Neuroscience, Ningbo Addiction Research and Treatment Center Ningbo China
| | - Wenhua Zhou
- Laboratory of Behavioral Neuroscience, Ningbo Addiction Research and Treatment Center Ningbo China
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Croall ID, Tozer DJ, Moynihan B, Khan U, O’Brien JT, Morris RG, Cambridge VC, Barrick TR, Blamire AM, Ford GA, Markus HS. Effect of Standard vs Intensive Blood Pressure Control on Cerebral Blood Flow in Small Vessel Disease: The PRESERVE Randomized Clinical Trial. JAMA Neurol 2018; 75:720-727. [PMID: 29507944 PMCID: PMC5885221 DOI: 10.1001/jamaneurol.2017.5153] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Importance Blood pressure (BP) lowering is considered neuroprotective in patients with cerebral small vessel disease; however, more intensive regimens may increase cerebral hypoperfusion. This study examined the effect of standard vs intensive BP treatment on cerebral perfusion in patients with severe small vessel disease. Objective To investigate whether standard vs intensive BP lowering over 3 months causes decreased cerebral perfusion in small vessel disease. Design, Setting, and Participants This randomized clinical trial took place at 2 English university medical centers. Patients were randomized via a central online system (in a 1:1 ratio). Seventy patients with hypertension and with magnetic resonance imaging-confirmed symptomatic lacunar infarct and confluent white matter hyperintensities were recruited between February 29, 2012, and October 21, 2015, and randomized (36 in the standard group and 34 in the intensive group). Analyzable data were available in 62 patients, 33 in the standard group and 29 in the intensive group, for intent-to-treat analysis. This experiment examines the 3-month follow-up period. Interventions Patients were randomized to standard (systolic, 130-140 mm Hg) or intensive (systolic, <125 mm Hg) BP targets, to be achieved through medication changes. Main Outcomes and Measures Cerebral perfusion was measured using arterial spin labeling; the primary end point was change in global perfusion between baseline and 3 months, compared between treatment groups by analysis of variance. Linear regression compared change in perfusion against change in BP. Magnetic resonance imaging scan analysis was masked to treatment group. Results Among 62 analyzable patients, the mean age was 69.3 years, and 60% (n = 37) were male. The mean (SD) systolic BP decreased by 8 (12) mm Hg in the standard group and by 27 (17) mm Hg in the intensive group (P < .001), with mean (SD) achieved pressures of 141 (13) and 126 (10) mm Hg, respectively. Change in global perfusion did not differ between treatment groups: the mean (SD) change was -0.5 (9.4) mL/min/100 g in the standard group vs 0.7 (8.6) mL/min/100 g in the intensive group (partial η2, 0.004; 95% CI, -3.551 to 5.818; P = .63). No differences were observed when the analysis examined gray or white matter only or was confined to those achieving target BP. The number of adverse events did not differ between treatment groups, with a mean (SD) of 0.21 (0.65) for the standard group and 0.32 (0.75) for the intensive group (P = .44). Conclusions and Relevance Intensive BP lowering did not reduce cerebral perfusion in severe small vessel disease. Trial Registration isrctn.org Identifier: ISRCTN37694103.
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Affiliation(s)
- Iain D. Croall
- Stroke Research Group, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Daniel J. Tozer
- Stroke Research Group, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Barry Moynihan
- St George’s National Health Service Healthcare Trust, London, United Kingdom
| | - Usman Khan
- St George’s National Health Service Healthcare Trust, London, United Kingdom
| | - John T. O’Brien
- Department of Psychiatry, University of Cambridge, Cambridge, United Kingdom
| | - Robin G. Morris
- Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, United Kingdom
| | - Victoria C. Cambridge
- Stroke Research Group, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Thomas R. Barrick
- Molecular and Clinical Sciences Research Institute, St George’s, University of London, London, United Kingdom
| | - Andrew M. Blamire
- Magnetic Resonance Centre, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Gary A. Ford
- Oxford University Hospitals National Health Service Foundation Trust, Oxford, United Kingdom
| | - Hugh S. Markus
- Stroke Research Group, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
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Hase Y, Horsburgh K, Ihara M, Kalaria RN. White matter degeneration in vascular and other ageing-related dementias. J Neurochem 2018; 144:617-633. [DOI: 10.1111/jnc.14271] [Citation(s) in RCA: 118] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 10/20/2017] [Accepted: 11/20/2017] [Indexed: 12/11/2022]
Affiliation(s)
- Yoshiki Hase
- Neurovascular Research Group; Institute of Neuroscience; Newcastle University; Newcastle Upon Tyne UK
| | - Karen Horsburgh
- Centre for Neuroregeneration; University of Edinburgh; Edinburgh UK
| | - Masafumi Ihara
- Department of Neurology; National Cerebral and Cardiovascular Center; Suita Osaka Japan
| | - Raj N. Kalaria
- Neurovascular Research Group; Institute of Neuroscience; Newcastle University; Newcastle Upon Tyne UK
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Robertson AD, Matta G, Basile VS, Black SE, Macgowan CK, Detre JA, MacIntosh BJ. Temporal and Spatial Variances in Arterial Spin-Labeling Are Inversely Related to Large-Artery Blood Velocity. AJNR Am J Neuroradiol 2017; 38:1555-1561. [PMID: 28619834 DOI: 10.3174/ajnr.a5257] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 04/10/2017] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE The relationship between extracranial large-artery characteristics and arterial spin-labeling MR imaging may influence the quality of arterial spin-labeling-CBF images for older adults with and without vascular pathology. We hypothesized that extracranial arterial blood velocity can explain between-person differences in arterial spin-labeling data systematically across clinical populations. MATERIALS AND METHODS We performed consecutive pseudocontinuous arterial spin-labeling and phase-contrast MR imaging on 82 individuals (20-88 years of age, 50% women), including healthy young adults, healthy older adults, and older adults with cerebral small vessel disease or chronic stroke infarcts. We examined associations between extracranial phase-contrast hemodynamics and intracranial arterial spin-labeling characteristics, which were defined by labeling efficiency, temporal signal-to-noise ratio, and spatial coefficient of variation. RESULTS Large-artery blood velocity was inversely associated with labeling efficiency (P = .007), temporal SNR (P < .001), and spatial coefficient of variation (P = .05) of arterial spin-labeling, after accounting for age, sex, and group. Correction for labeling efficiency on an individual basis led to additional group differences in GM-CBF compared to correction using a constant labeling efficiency. CONCLUSIONS Between-subject arterial spin-labeling variance was partially explained by extracranial velocity but not cross-sectional area. Choosing arterial spin-labeling timing parameters with on-line knowledge of blood velocity may improve CBF quantification.
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Affiliation(s)
- A D Robertson
- From the Heart and Stroke Foundation Canadian Partnership for Stroke Recovery (A.D.R., G.M., S.E.B., B.J.M.) .,Hurvitz Brain Sciences (A.D.R., S.E.B., B.J.M.), Sunnybrook Research Institute, University of Toronto, Toronto, Ontario, Canada
| | - G Matta
- From the Heart and Stroke Foundation Canadian Partnership for Stroke Recovery (A.D.R., G.M., S.E.B., B.J.M.)
| | - V S Basile
- Division of Neurology, Department of Medicine (V.S.B., S.E.B.), University of Toronto, Toronto, Ontario, Canada.,Mackenzie Health (V.S.B.), Richmond Hill, Ontario, Canada
| | - S E Black
- From the Heart and Stroke Foundation Canadian Partnership for Stroke Recovery (A.D.R., G.M., S.E.B., B.J.M.).,Hurvitz Brain Sciences (A.D.R., S.E.B., B.J.M.), Sunnybrook Research Institute, University of Toronto, Toronto, Ontario, Canada.,Division of Neurology, Department of Medicine (V.S.B., S.E.B.), University of Toronto, Toronto, Ontario, Canada.,L.C. Campbell Cognitive Neurology Research Unit (S.E.B.), Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
| | - C K Macgowan
- Hospital for Sick Children (C.K.M.), Toronto, Ontario, Canada.,Department of Medical Biophysics (C.K.M., B.J.M.), University of Toronto, Toronto, Ontario, Canada
| | - J A Detre
- Department of Neurology (J.A.D.), University of Pennsylvania, Philadelphia, Pennsylvania
| | - B J MacIntosh
- From the Heart and Stroke Foundation Canadian Partnership for Stroke Recovery (A.D.R., G.M., S.E.B., B.J.M.).,Hurvitz Brain Sciences (A.D.R., S.E.B., B.J.M.), Sunnybrook Research Institute, University of Toronto, Toronto, Ontario, Canada.,Department of Medical Biophysics (C.K.M., B.J.M.), University of Toronto, Toronto, Ontario, Canada
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17
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Haller S, Zaharchuk G, Thomas DL, Lovblad KO, Barkhof F, Golay X. Arterial Spin Labeling Perfusion of the Brain: Emerging Clinical Applications. Radiology 2017; 281:337-356. [PMID: 27755938 DOI: 10.1148/radiol.2016150789] [Citation(s) in RCA: 333] [Impact Index Per Article: 47.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Arterial spin labeling (ASL) is a magnetic resonance (MR) imaging technique used to assess cerebral blood flow noninvasively by magnetically labeling inflowing blood. In this article, the main labeling techniques, notably pulsed and pseudocontinuous ASL, as well as emerging clinical applications will be reviewed. In dementia, the pattern of hypoperfusion on ASL images closely matches the established patterns of hypometabolism on fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) images due to the close coupling of perfusion and metabolism in the brain. This suggests that ASL might be considered as an alternative for FDG, reserving PET to be used for the molecular disease-specific amyloid and tau tracers. In stroke, ASL can be used to assess perfusion alterations both in the acute and the chronic phase. In arteriovenous malformations and dural arteriovenous fistulas, ASL is very sensitive to detect even small degrees of shunting. In epilepsy, ASL can be used to assess the epileptogenic focus, both in peri- and interictal period. In neoplasms, ASL is of particular interest in cases in which gadolinium-based perfusion is contraindicated (eg, allergy, renal impairment) and holds promise in differentiating tumor progression from benign causes of enhancement. Finally, various neurologic and psychiatric diseases including mild traumatic brain injury or posttraumatic stress disorder display alterations on ASL images in the absence of visualized structural changes. In the final part, current limitations and future developments of ASL techniques to improve clinical applicability, such as multiple inversion time ASL sequences to assess alterations of transit time, reproducibility and quantification of cerebral blood flow, and to measure cerebrovascular reserve, will be reviewed. © RSNA, 2016 Online supplemental material is available for this article.
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Affiliation(s)
- Sven Haller
- From Affidea Centre Diagnostique Radiologique de Carouge, Clos de la Fonderie 1, 1227 Carouge, Switzerland (S.H.); Dept of Surgical Sciences, Div of Radiology, Uppsala Univ, Sweden (S.H.); Dept of Neuroradiology, Univ Hosp Freiburg, Germany (S.H.); Faculty of Medicine Univ of Geneva, Switzerland (S.H.); Dept of Radiology, Stanford Univ, Stanford, Calif (G.Z.); Univ College London, Inst of Neurology, London, England (D.L.T., X.G.); Dept of Diagnostic and Interventional Neuroradiology, Geneva Univ Hosps,Switzerland (K.O.L.); Dept of Radiology & Nuclear Medicine and PET Research, VU Univ Medical Ctr, Amsterdam, the Netherlands (F.B.); and Insts of Neurology and Healthcare Engineering, Univ College London, England (F.B.)
| | - Greg Zaharchuk
- From Affidea Centre Diagnostique Radiologique de Carouge, Clos de la Fonderie 1, 1227 Carouge, Switzerland (S.H.); Dept of Surgical Sciences, Div of Radiology, Uppsala Univ, Sweden (S.H.); Dept of Neuroradiology, Univ Hosp Freiburg, Germany (S.H.); Faculty of Medicine Univ of Geneva, Switzerland (S.H.); Dept of Radiology, Stanford Univ, Stanford, Calif (G.Z.); Univ College London, Inst of Neurology, London, England (D.L.T., X.G.); Dept of Diagnostic and Interventional Neuroradiology, Geneva Univ Hosps,Switzerland (K.O.L.); Dept of Radiology & Nuclear Medicine and PET Research, VU Univ Medical Ctr, Amsterdam, the Netherlands (F.B.); and Insts of Neurology and Healthcare Engineering, Univ College London, England (F.B.)
| | - David L Thomas
- From Affidea Centre Diagnostique Radiologique de Carouge, Clos de la Fonderie 1, 1227 Carouge, Switzerland (S.H.); Dept of Surgical Sciences, Div of Radiology, Uppsala Univ, Sweden (S.H.); Dept of Neuroradiology, Univ Hosp Freiburg, Germany (S.H.); Faculty of Medicine Univ of Geneva, Switzerland (S.H.); Dept of Radiology, Stanford Univ, Stanford, Calif (G.Z.); Univ College London, Inst of Neurology, London, England (D.L.T., X.G.); Dept of Diagnostic and Interventional Neuroradiology, Geneva Univ Hosps,Switzerland (K.O.L.); Dept of Radiology & Nuclear Medicine and PET Research, VU Univ Medical Ctr, Amsterdam, the Netherlands (F.B.); and Insts of Neurology and Healthcare Engineering, Univ College London, England (F.B.)
| | - Karl-Olof Lovblad
- From Affidea Centre Diagnostique Radiologique de Carouge, Clos de la Fonderie 1, 1227 Carouge, Switzerland (S.H.); Dept of Surgical Sciences, Div of Radiology, Uppsala Univ, Sweden (S.H.); Dept of Neuroradiology, Univ Hosp Freiburg, Germany (S.H.); Faculty of Medicine Univ of Geneva, Switzerland (S.H.); Dept of Radiology, Stanford Univ, Stanford, Calif (G.Z.); Univ College London, Inst of Neurology, London, England (D.L.T., X.G.); Dept of Diagnostic and Interventional Neuroradiology, Geneva Univ Hosps,Switzerland (K.O.L.); Dept of Radiology & Nuclear Medicine and PET Research, VU Univ Medical Ctr, Amsterdam, the Netherlands (F.B.); and Insts of Neurology and Healthcare Engineering, Univ College London, England (F.B.)
| | - Frederik Barkhof
- From Affidea Centre Diagnostique Radiologique de Carouge, Clos de la Fonderie 1, 1227 Carouge, Switzerland (S.H.); Dept of Surgical Sciences, Div of Radiology, Uppsala Univ, Sweden (S.H.); Dept of Neuroradiology, Univ Hosp Freiburg, Germany (S.H.); Faculty of Medicine Univ of Geneva, Switzerland (S.H.); Dept of Radiology, Stanford Univ, Stanford, Calif (G.Z.); Univ College London, Inst of Neurology, London, England (D.L.T., X.G.); Dept of Diagnostic and Interventional Neuroradiology, Geneva Univ Hosps,Switzerland (K.O.L.); Dept of Radiology & Nuclear Medicine and PET Research, VU Univ Medical Ctr, Amsterdam, the Netherlands (F.B.); and Insts of Neurology and Healthcare Engineering, Univ College London, England (F.B.)
| | - Xavier Golay
- From Affidea Centre Diagnostique Radiologique de Carouge, Clos de la Fonderie 1, 1227 Carouge, Switzerland (S.H.); Dept of Surgical Sciences, Div of Radiology, Uppsala Univ, Sweden (S.H.); Dept of Neuroradiology, Univ Hosp Freiburg, Germany (S.H.); Faculty of Medicine Univ of Geneva, Switzerland (S.H.); Dept of Radiology, Stanford Univ, Stanford, Calif (G.Z.); Univ College London, Inst of Neurology, London, England (D.L.T., X.G.); Dept of Diagnostic and Interventional Neuroradiology, Geneva Univ Hosps,Switzerland (K.O.L.); Dept of Radiology & Nuclear Medicine and PET Research, VU Univ Medical Ctr, Amsterdam, the Netherlands (F.B.); and Insts of Neurology and Healthcare Engineering, Univ College London, England (F.B.)
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18
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Malojcic B, Giannakopoulos P, Sorond FA, Azevedo E, Diomedi M, Oblak JP, Carraro N, Boban M, Olah L, Schreiber SJ, Pavlovic A, Garami Z, Bornstein NM, Rosengarten B. Ultrasound and dynamic functional imaging in vascular cognitive impairment and Alzheimer's disease. BMC Med 2017; 15:27. [PMID: 28178960 PMCID: PMC5299782 DOI: 10.1186/s12916-017-0799-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 01/21/2017] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND The vascular contributions to neurodegeneration and neuroinflammation may be assessed by magnetic resonance imaging (MRI) and ultrasonography (US). This review summarises the methodology for these widely available, safe and relatively low cost tools and analyses recent work highlighting their potential utility as biomarkers for differentiating subtypes of cognitive impairment and dementia, tracking disease progression and evaluating response to treatment in various neurocognitive disorders. METHODS At the 9th International Congress on Vascular Dementia (Ljubljana, Slovenia, October 2015) a writing group of experts was formed to review the evidence on the utility of US and arterial spin labelling (ASL) as neurophysiological markers of normal ageing, vascular cognitive impairment (VCI) and Alzheimer's disease (AD). Original articles, systematic literature reviews, guidelines and expert opinions published until September 2016 were critically analysed to summarise existing evidence, indicate gaps in current knowledge and, when appropriate, suggest standards of use for the most widely used US and ASL applications. RESULTS Cerebral hypoperfusion has been linked to cognitive decline either as a risk or an aggravating factor. Hypoperfusion as a consequence of microangiopathy, macroangiopathy or cardiac dysfunction can promote or accelerate neurodegeneration, blood-brain barrier disruption and neuroinflammation. US can evaluate the cerebrovascular tree for pathological structure and functional changes contributing to cerebral hypoperfusion. Microvascular pathology and hypoperfusion at the level of capillaries and small arterioles can also be assessed by ASL, an MRI signal. Despite increasing evidence supporting the utility of these methods in detection of microvascular pathology, cerebral hypoperfusion, neurovascular unit dysfunction and, most importantly, disease progression, incomplete standardisation and missing validated cut-off values limit their use in daily routine. CONCLUSIONS US and ASL are promising tools with excellent temporal resolution, which will have a significant impact on our understanding of the vascular contributions to VCI and AD and may also be relevant for assessing future prevention and therapeutic strategies for these conditions. Our work provides recommendations regarding the use of non-invasive imaging techniques to investigate the functional consequences of vascular burden in dementia.
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Affiliation(s)
- Branko Malojcic
- Department of Neurology, University Hospital Center Zagreb, Zagreb School of Medicine, Kispaticeva 12, 10000, Zagreb, Croatia.
| | | | - Farzaneh A Sorond
- Department of Neurology, Northwestern University Feinberg School of Medicine Chicago, Chicago, IL, USA
| | - Elsa Azevedo
- Department of Neurology, São João Hospital Center and Faculty of Medicine of University of Porto, Porto, Portugal
| | - Marina Diomedi
- Cerebrovascular Disease Center, Stroke Unit, University of Rome Tor Vergata, Rome, Italy
| | - Janja Pretnar Oblak
- Department of Vascular Neurology and Intensive Therapy, University Medical Center Ljubljana, Ljubljana, Slovenia
| | - Nicola Carraro
- Department of Medical Sciences, Clinical Neurology-Stroke Unit, University Hospital, University of Trieste, Trieste, Italy
| | - Marina Boban
- Department of Neurology, University Hospital Center Zagreb, Zagreb School of Medicine, Kispaticeva 12, 10000, Zagreb, Croatia
| | - Laszlo Olah
- Department of Neurology, University of Debrecen, Debrecen, Hungary
| | - Stephan J Schreiber
- Department of Neurology, Charite - Universitätsmedizin Berlin, Berlin, Germany
| | - Aleksandra Pavlovic
- Neurology Clinic, Clinical Center of Serbia, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Zsolt Garami
- Methodist DeBakey Heart and Vascular Center, Houston, TX, USA
| | - Nantan M Bornstein
- Neurology Department, Tel Aviv Sourasky Medical Centre, Tel Aviv, Israel
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Zhang N, Gordon ML, Goldberg TE. Cerebral blood flow measured by arterial spin labeling MRI at resting state in normal aging and Alzheimer’s disease. Neurosci Biobehav Rev 2017; 72:168-175. [DOI: 10.1016/j.neubiorev.2016.11.023] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 11/12/2016] [Accepted: 11/25/2016] [Indexed: 10/20/2022]
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20
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The pathophysiological role of astrocytic endothelin-1. Prog Neurobiol 2016; 144:88-102. [DOI: 10.1016/j.pneurobio.2016.04.009] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 03/23/2016] [Accepted: 04/25/2016] [Indexed: 12/13/2022]
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Abstract
Vascular dementia (VaD) is a major contributor to the dementia syndrome and is described as having problems with reasoning, planning, judgment, and memory caused by impaired blood flow to the brain and damage to the blood vessels resulting from events such as stroke. There are a variety of etiologies that contribute to the development of vascular cognitive impairment and VaD, and these are often associated with other dementia-related pathologies such as Alzheimer disease. The diagnosis of VaD is difficult due to the number and types of lesions and their locations in the brain. Factors that increase the risk of vascular diseases such as stroke, high blood pressure, high cholesterol, and smoking also raise the risk of VaD. Therefore, controlling these risk factors can help lower the chances of developing VaD. This update describes the subtypes of VaD, with details of their complex presentation, associated pathological lesions, and issues with diagnosis, prevention, and treatment.
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Affiliation(s)
- Ayesha Khan
- Wolfson Centre for Age Related Diseases, Guys Campus, London, United Kingdom of Great Britain and Northern Ireland Institute of NanoBioTechnology, Johns Hopkins University, Baltimore, MD, USA
| | - Raj N Kalaria
- Institute for Ageing and Health, Wolfson Research Centre, Campus for Ageing & Vitality, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Anne Corbett
- Wolfson Centre for Age Related Diseases, Guys Campus, London, United Kingdom of Great Britain and Northern Ireland
| | - Clive Ballard
- Wolfson Centre for Age Related Diseases, Guys Campus, London, United Kingdom of Great Britain and Northern Ireland
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The Age-Dependent Relationship between Blood Pressure and Cognitive Impairment: A Cross-Sectional Study in a Rural Area of Xi'an, China. PLoS One 2016; 11:e0159485. [PMID: 27438476 PMCID: PMC4954703 DOI: 10.1371/journal.pone.0159485] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 07/04/2016] [Indexed: 12/02/2022] Open
Abstract
Background Hypertension is a modifiable risk factor for cognitive impairment, although the relationship between hypertension and cognitive impairment is not fully understood. The objective of this study was to investigate the effect of age on the relationship between blood pressure and cognitive impairment. Methods Blood pressure and global cognitive function information was collected from 1799 participants (age 40–85) who lived in a village in the suburbs of Xi'an, China, during in-person interviews. Cognitive impairment was defined as a Mini-Mental State Examination (MMSE) score lower than the cutoff value. The effect of age on the relationship between blood pressure parameters [systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MABP), and high blood pressure (HBP, SBP≥140 mm Hg and/or DBP≥90 mm Hg)] and cognitive impairment was analyzed by logistic regression models using interaction and stratified analysis. Blood pressure and age were regarded as both continuous and categorical data. Results A total of 231 participants were diagnosed as having cognitive impairment based on our criteria. Interaction analysis for the total population showed that SBP (when regarded as continuous data) was positively correlated with cognitive impairment (OR = 1.130 [95% CI, 1.028–1.242] per 10mmHg, P = 0.011); however, the age by SBP interaction term was negatively correlated with cognitive impairment (OR = 0.989 [95% CI, 0.982–0.997] per 10mmHg×year, P = 0.006), indicating that the relationship between SBP and cognitive impairment was age-dependent (OR = 1.130×0.989(age-55.5) per 10mmHg,40 ≤age≤85). When the blood pressure and age were considered as binary data, the results were similar to those obtained when they were considered as continuous variables. Stratified multivariate analysis revealed that the relationship between SBP (when regarded as continuous data) and cognitive impairment was positive for patients aged 40–49 years (OR = 1.349 [95% CI: 1.039–1.753] per 10mmHg, P = 0.025) and 50–59 years (OR = 1.185 [95% CI: 1.028–1.366] per 10mmHg, P = 0.019), whereas it tended to be negative for patients aged 60–69 years (OR = 0.878 [95% CI: 0.729–1.058] per 10mmHg, P = 0.171) and ≥70 years (OR = 0.927 [95% CI: 0.772–1.113] per 10mmHg, P = 0.416). Results similar to those for SBP were obtained for DBP, MABP and HBP as well. Subsequently, SBP, DBP and MABP were transformed into categorical data (SBP<140mmHg, 140mmHg≤SBP<160mmHg, and SBP≥160mmHg; DBP<90mmHg, 90mmHg≤DBP<100mmHg, and DBP≥100mmHg; MABP<100mmHg, 100mmHg≤MABP<110mmHg, and MABP≥110mmHg), and the stratified multivariate analysis was repeated. This analysis showed that the age-dependent association continued to exist and was especially prominent in the SBP≥160 mmHg, DBP≥90 mmHg and MABP≥110 mmHg groups. Conclusions Elevated blood pressure is positively correlated with cognitive impairment in the middle-aged, but this positive association declines with increasing age. These results indicated that specific blood pressure management strategies for various age groups may be crucial for maintaining cognitive vitality.
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Montagne A, Nation DA, Pa J, Sweeney MD, Toga AW, Zlokovic BV. Brain imaging of neurovascular dysfunction in Alzheimer's disease. Acta Neuropathol 2016; 131:687-707. [PMID: 27038189 PMCID: PMC5283382 DOI: 10.1007/s00401-016-1570-0] [Citation(s) in RCA: 155] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 03/21/2016] [Accepted: 03/23/2016] [Indexed: 11/29/2022]
Abstract
Neurovascular dysfunction, including blood-brain barrier (BBB) breakdown and cerebral blood flow (CBF) dysregulation and reduction, are increasingly recognized to contribute to Alzheimer's disease (AD). The spatial and temporal relationships between different pathophysiological events during preclinical stages of AD, including cerebrovascular dysfunction and pathology, amyloid and tau pathology, and brain structural and functional changes remain, however, still unclear. Recent advances in neuroimaging techniques, i.e., magnetic resonance imaging (MRI) and positron emission tomography (PET), offer new possibilities to understand how the human brain works in health and disease. This includes methods to detect subtle regional changes in the cerebrovascular system integrity. Here, we focus on the neurovascular imaging techniques to evaluate regional BBB permeability (dynamic contrast-enhanced MRI), regional CBF changes (arterial spin labeling- and functional-MRI), vascular pathology (structural MRI), and cerebral metabolism (PET) in the living human brain, and examine how they can inform about neurovascular dysfunction and vascular pathophysiology in dementia and AD. Altogether, these neuroimaging approaches will continue to elucidate the spatio-temporal progression of vascular and neurodegenerative processes in dementia and AD and how they relate to each other.
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Affiliation(s)
- Axel Montagne
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90089, USA
| | - Daniel A Nation
- Department of Psychology, University of Southern California, Los Angeles, CA, 90089, USA
| | - Judy Pa
- Department of Neurology, Institute for Neuroimaging and Informatics, University of Southern California, Los Angeles, CA, 90089, USA
| | - Melanie D Sweeney
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90089, USA
| | - Arthur W Toga
- Department of Neurology, Institute for Neuroimaging and Informatics, University of Southern California, Los Angeles, CA, 90089, USA
| | - Berislav V Zlokovic
- Zilkha Neurogenetic Institute and Department of Physiology and Biophysics, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90089, USA.
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24
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Neuropathological diagnosis of vascular cognitive impairment and vascular dementia with implications for Alzheimer's disease. Acta Neuropathol 2016; 131:659-85. [PMID: 27062261 PMCID: PMC4835512 DOI: 10.1007/s00401-016-1571-z] [Citation(s) in RCA: 260] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 03/23/2016] [Accepted: 03/24/2016] [Indexed: 12/16/2022]
Abstract
Vascular dementia (VaD) is recognised as a neurocognitive disorder, which is explained by numerous vascular causes in the general absence of other pathologies. The heterogeneity of cerebrovascular disease makes it challenging to elucidate the neuropathological substrates and mechanisms of VaD as well as vascular cognitive impairment (VCI). Consensus and accurate diagnosis of VaD relies on wide-ranging clinical, neuropsychometric and neuroimaging measures with subsequent pathological confirmation. Pathological diagnosis of suspected clinical VaD requires adequate postmortem brain sampling and rigorous assessment methods to identify important substrates. Factors that define the subtypes of VaD include the nature and extent of vascular pathologies, degree of involvement of extra and intracranial vessels and the anatomical location of tissue changes. Atherosclerotic and cardioembolic diseases appear the most common substrates of vascular brain injury or infarction. Small vessel disease characterised by arteriolosclerosis and lacunar infarcts also causes cortical and subcortical microinfarcts, which appear to be the most robust substrates of cognitive impairment. Diffuse WM changes with loss of myelin and axonal abnormalities are common to almost all subtypes of VaD. Medial temporal lobe and hippocampal atrophy accompanied by variable hippocampal sclerosis are also features of VaD as they are of Alzheimer’s disease. Recent observations suggest that there is a vascular basis for neuronal atrophy in both the temporal and frontal lobes in VaD that is entirely independent of any Alzheimer pathology. Further knowledge on specific neuronal and dendro-synaptic changes in key regions resulting in executive dysfunction and other cognitive deficits, which define VCI and VaD, needs to be gathered. Hereditary arteriopathies such as cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy or CADASIL have provided insights into the mechanisms of dementia associated with cerebral small vessel disease. Greater understanding of the neurochemical and molecular investigations is needed to better define microvascular disease and vascular substrates of dementia. The investigation of relevant animal models would be valuable in exploring the pathogenesis as well as prevention of the vascular causes of cognitive impairment.
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25
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Hays CC, Zlatar ZZ, Wierenga CE. The Utility of Cerebral Blood Flow as a Biomarker of Preclinical Alzheimer's Disease. Cell Mol Neurobiol 2016; 36:167-79. [PMID: 26898552 DOI: 10.1007/s10571-015-0261-z] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 08/25/2015] [Indexed: 12/20/2022]
Abstract
There is accumulating evidence suggesting that changes in brain perfusion are present long before the clinical symptoms of Alzheimer's disease (AD), perhaps even before amyloid-β accumulation or brain atrophy. This evidence, consistent with the vascular hypothesis of AD, implicates cerebral blood flow (CBF) in the pathogenesis of AD and suggests its utility as a biomarker of preclinical AD. The extended preclinical phase of AD holds particular significance for disease modification, as treatment would likely be most effective in this early asymptomatic stage of disease. This highlights the importance of identifying reliable and accurate biomarkers of AD that can differentiate normal aging from preclinical AD prior to clinical symptom manifestation. Cerebral perfusion, as measured by arterial spin labeling magnetic resonance imaging (ASL-MRI), has been shown to distinguish between normal controls and adults with AD. In addition to demonstrating diagnostic utility, CBF has shown usefulness as a tool for identifying those who are at risk for AD and for predicting subtle cognitive decline and conversion to mild cognitive impairment and AD. Taken together, this evidence not only implicates CBF as a useful biomarker for tracking disease severity and progression, but also suggests that ASL-measured CBF may be useful for identifying candidates for future AD treatment trials, especially in the preclinical, asymptomatic phases of the disease.
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Affiliation(s)
- Chelsea C Hays
- VA San Diego Healthcare System, 3350 La Jolla Village Dr., MC 151B, San Diego, CA, 92161, USA.,SDSU/UC San Diego Joint Doctoral Program in Clinical Psychology, 6363 Alvarado Court, Suite 103, San Diego, CA, 92120, USA
| | - Zvinka Z Zlatar
- VA San Diego Healthcare System, 3350 La Jolla Village Dr., MC 151B, San Diego, CA, 92161, USA.,Department of Psychiatry, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, USA
| | - Christina E Wierenga
- VA San Diego Healthcare System, 3350 La Jolla Village Dr., MC 151B, San Diego, CA, 92161, USA. .,Department of Psychiatry, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA, 92093, USA.
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26
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Kalaria RN, Akinyemi R, Ihara M. Stroke injury, cognitive impairment and vascular dementia. Biochim Biophys Acta Mol Basis Dis 2016; 1862:915-25. [PMID: 26806700 PMCID: PMC4827373 DOI: 10.1016/j.bbadis.2016.01.015] [Citation(s) in RCA: 317] [Impact Index Per Article: 39.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 01/18/2016] [Accepted: 01/20/2016] [Indexed: 12/13/2022]
Abstract
The global burden of ischaemic strokes is almost 4-fold greater than haemorrhagic strokes. Current evidence suggests that 25–30% of ischaemic stroke survivors develop immediate or delayed vascular cognitive impairment (VCI) or vascular dementia (VaD). Dementia after stroke injury may encompass all types of cognitive disorders. States of cognitive dysfunction before the index stroke are described under the umbrella of pre-stroke dementia, which may entail vascular changes as well as insidious neurodegenerative processes. Risk factors for cognitive impairment and dementia after stroke are multifactorial including older age, family history, genetic variants, low educational status, vascular comorbidities, prior transient ischaemic attack or recurrent stroke and depressive illness. Neuroimaging determinants of dementia after stroke comprise silent brain infarcts, white matter changes, lacunar infarcts and medial temporal lobe atrophy. Until recently, the neuropathology of dementia after stroke was poorly defined. Most of post-stroke dementia is consistent with VaD involving multiple substrates. Microinfarction, microvascular changes related to blood–brain barrier damage, focal neuronal atrophy and low burden of co-existing neurodegenerative pathology appear key substrates of dementia after stroke injury. The elucidation of mechanisms of dementia after stroke injury will enable establishment of effective strategy for symptomatic relief and prevention. Controlling vascular disease risk factors is essential to reduce the burden of cognitive dysfunction after stroke. 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. Ischaemic injury is common among long-term stroke survivors About 25% stroke survivors develop dementia with a much greater proportion developing cognitive impairment Risk factors of dementia after stroke include older age, vascular comorbidities, prior stroke and pre-stroke impairment Current imaging and pathological studies suggest 70% of dementia after stroke is vascular dementia Severe white matter changes and medial temporal lobe atrophy as sequelae after ischaemic injury are substrates of dementia Controlling vascular risk factors and prevention strategies related to lifestyle factors would reduce dementia after stroke
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Affiliation(s)
- Raj N Kalaria
- Institute of Neuroscience, Newcastle University, Campus for Ageing & Vitality, Newcastle upon Tyne, NE4 5PL, United Kingdom; Neuroscience and Ageing Research Unit, Institute for Advanced Medical Research and Training, College of Medicine, University of Ibadan, Nigeria; Department of Stroke and Cerebrovascular Diseases, National Cerebral and Cardiovascular Center, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565, Japan.
| | - Rufus Akinyemi
- Institute of Neuroscience, Newcastle University, Campus for Ageing & Vitality, Newcastle upon Tyne, NE4 5PL, United Kingdom; Neuroscience and Ageing Research Unit, Institute for Advanced Medical Research and Training, College of Medicine, University of Ibadan, Nigeria; Department of Stroke and Cerebrovascular Diseases, National Cerebral and Cardiovascular Center, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565, Japan
| | - Masafumi Ihara
- Institute of Neuroscience, Newcastle University, Campus for Ageing & Vitality, Newcastle upon Tyne, NE4 5PL, United Kingdom; Neuroscience and Ageing Research Unit, Institute for Advanced Medical Research and Training, College of Medicine, University of Ibadan, Nigeria; Department of Stroke and Cerebrovascular Diseases, National Cerebral and Cardiovascular Center, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565, Japan
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27
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Chen A, Akinyemi RO, Hase Y, Firbank MJ, Ndung'u MN, Foster V, Craggs LJL, Washida K, Okamoto Y, Thomas AJ, Polvikoski TM, Allan LM, Oakley AE, O'Brien JT, Horsburgh K, Ihara M, Kalaria RN. Frontal white matter hyperintensities, clasmatodendrosis and gliovascular abnormalities in ageing and post-stroke dementia. Brain 2015; 139:242-58. [PMID: 26667280 PMCID: PMC4905522 DOI: 10.1093/brain/awv328] [Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 09/29/2015] [Indexed: 01/16/2023] Open
Abstract
White matter hyperintensities as seen on brain T
2
-weighted magnetic resonance imaging are associated with varying degrees of cognitive dysfunction in stroke, cerebral small vessel disease and dementia. The pathophysiological mechanisms within the white matter accounting for cognitive dysfunction remain unclear. With the hypothesis that gliovascular interactions are impaired in subjects with high burdens of white matter hyperintensities, we performed clinicopathological studies in post-stroke survivors, who had exhibited greater frontal white matter hyperintensities volumes that predicted shorter time to dementia onset. Histopathological methods were used to identify substrates in the white matter that would distinguish post-stroke demented from post-stroke non-demented subjects. We focused on the reactive cell marker glial fibrillary acidic protein (GFAP) to study the incidence and location of clasmatodendrosis, a morphological attribute of irreversibly injured astrocytes. In contrast to normal appearing GFAP+ astrocytes, clasmatodendrocytes were swollen and had vacuolated cell bodies. Other markers such as aldehyde dehydrogenase 1 family, member L1 (ALDH1L1) showed cytoplasmic disintegration of the astrocytes. Total GFAP+ cells in both the frontal and temporal white matter were not greater in post-stroke demented versus post-stroke non-demented subjects. However, the percentage of clasmatodendrocytes was increased by >2-fold in subjects with post-stroke demented compared to post-stroke non-demented subjects (
P =
0.026) and by 11-fold in older controls versus young controls (
P <
0.023) in the frontal white matter. High ratios of clasmotodendrocytes to total astrocytes in the frontal white matter were consistent with lower Mini-Mental State Examination and the revised Cambridge Cognition Examination scores in post-stroke demented subjects. Double immunofluorescent staining showed aberrant co-localization of aquaporin 4 (AQP4) in retracted GFAP+ astrocytes with disrupted end-feet juxtaposed to microvessels. To explore whether this was associated with the disrupted gliovascular interactions or blood–brain barrier damage, we assessed the co-localization of GFAP and AQP4 immunoreactivities in post-mortem brains from adult baboons with cerebral hypoperfusive injury, induced by occlusion of three major vessels supplying blood to the brain. Analysis of the frontal white matter in perfused brains from the animals surviving 1–28 days after occlusion revealed that the highest intensity of fibrinogen immunoreactivity was at 14 days. At this survival time point, we also noted strikingly similar redistribution of AQP4 and GFAP+ astrocytes transformed into clasmatodendrocytes. Our findings suggest novel associations between irreversible astrocyte injury and disruption of gliovascular interactions at the blood–brain barrier in the frontal white matter and cognitive impairment in elderly post-stroke survivors. We propose that clasmatodendrosis is another pathological substrate, linked to white matter hyperintensities and frontal white matter changes, which may contribute to post-stroke or small vessel disease dementia.
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Affiliation(s)
- Aiqing Chen
- 1 Neurovascular Research Group, Institute of Neuroscience, Newcastle University, Campus for Ageing and Vitality, Newcastle Upon Tyne, UK
| | - Rufus O Akinyemi
- 1 Neurovascular Research Group, Institute of Neuroscience, Newcastle University, Campus for Ageing and Vitality, Newcastle Upon Tyne, UK
| | - Yoshiki Hase
- 1 Neurovascular Research Group, Institute of Neuroscience, Newcastle University, Campus for Ageing and Vitality, Newcastle Upon Tyne, UK
| | - Michael J Firbank
- 1 Neurovascular Research Group, Institute of Neuroscience, Newcastle University, Campus for Ageing and Vitality, Newcastle Upon Tyne, UK
| | | | - Vincent Foster
- 1 Neurovascular Research Group, Institute of Neuroscience, Newcastle University, Campus for Ageing and Vitality, Newcastle Upon Tyne, UK
| | - Lucy J L Craggs
- 1 Neurovascular Research Group, Institute of Neuroscience, Newcastle University, Campus for Ageing and Vitality, Newcastle Upon Tyne, UK
| | - Kazuo Washida
- 1 Neurovascular Research Group, Institute of Neuroscience, Newcastle University, Campus for Ageing and Vitality, Newcastle Upon Tyne, UK
| | - Yoko Okamoto
- 1 Neurovascular Research Group, Institute of Neuroscience, Newcastle University, Campus for Ageing and Vitality, Newcastle Upon Tyne, UK
| | - Alan J Thomas
- 1 Neurovascular Research Group, Institute of Neuroscience, Newcastle University, Campus for Ageing and Vitality, Newcastle Upon Tyne, UK
| | - Tuomo M Polvikoski
- 1 Neurovascular Research Group, Institute of Neuroscience, Newcastle University, Campus for Ageing and Vitality, Newcastle Upon Tyne, UK
| | - Louise M Allan
- 1 Neurovascular Research Group, Institute of Neuroscience, Newcastle University, Campus for Ageing and Vitality, Newcastle Upon Tyne, UK
| | - Arthur E Oakley
- 1 Neurovascular Research Group, Institute of Neuroscience, Newcastle University, Campus for Ageing and Vitality, Newcastle Upon Tyne, UK
| | - John T O'Brien
- 1 Neurovascular Research Group, Institute of Neuroscience, Newcastle University, Campus for Ageing and Vitality, Newcastle Upon Tyne, UK
| | - Karen Horsburgh
- 3 Centre for Neuroregeneration, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK
| | - Masafumi Ihara
- 4 Department of Stroke and Cerebrovascular Diseases, National Cerebral and Cardiovascular Center, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565, Japan
| | - Raj N Kalaria
- 1 Neurovascular Research Group, Institute of Neuroscience, Newcastle University, Campus for Ageing and Vitality, Newcastle Upon Tyne, UK
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Mukaetova-Ladinska EB, Li M, Kalaria RN. tau protein, ischemic injury and vascular dementia. FUTURE NEUROLOGY 2015. [DOI: 10.2217/fnl.15.46] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Clinical, neuroimaging and neuropathological studies have confirmed overlap between Alzheimer's disease (AD) and vascular dementia (VaD). Classical neuropathological changes of AD (plaques and tangles) can be present in VaD. We review neuroimaging, biochemical and animal studies to consider the role of tau protein in ischemic injury and VaD pathogenesis. The evidence comes largely from transgenic animal studies that confirm that tau transgenes influence cerebral vasculature. Clinicobiochemical studies in the cerebrospinal fluid (CSF) have, similarly, confirmed alterations in both total and phosphorylated tau protein in VaD. These data suggest that tau protein not only serves as a potential diagnostic tool for differential diagnosis of VaD from other types of dementia, but may also be a therapeutic target in ischemic stroke.
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Affiliation(s)
| | - Mosi Li
- Centre for Neuroregeneration, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Raj N Kalaria
- Institute of Neuroscience, Newcastle University, Campus for Ageing & Vitality, Newcastle upon Tyne, NE4 5PL, UK
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Wierenga CE, Hays CC, Zlatar ZZ. Cerebral blood flow measured by arterial spin labeling MRI as a preclinical marker of Alzheimer's disease. J Alzheimers Dis 2015; 42 Suppl 4:S411-9. [PMID: 25159672 DOI: 10.3233/jad-141467] [Citation(s) in RCA: 153] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
There is growing recognition that cerebral hypoperfusion is related to the pathogenesis of Alzheimer's disease (AD), implicating the measurement of cerebral blood flow (CBF) as a possible biomarker of AD. The ability to identify the earliest and most reliable markers of incipient cognitive decline and clinical symptoms is critical to develop effective preventive strategies and interventions for AD. Arterial spin labeling (ASL) magnetic resonance imaging (MRI) measures CBF by magnetically labeling arterial water and using it as an endogenous tracer. Studies using ASL MRI in humans indicate that CBF changes are present several years before the development of the clinical symptoms of AD. Moreover, ASL-measured CBF has been shown to distinguish between cognitively normal individuals, adults at risk for AD, and persons diagnosed with AD. Some studies indicate that CBF may even be sensitive for predicting cognitive decline and conversion to mild cognitive impairment and AD over time. Taken together, evidence suggests that the current staging models of AD biomarker pathology should incorporate early changes in CBF as a useful biomarker, possibly present even earlier than amyloid-β accumulation. Though still a research tool, ASL imaging is a promising non-invasive and reliable method with the potential to serve as a future clinical tool for the measurement of CBF in preclinical AD.
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Affiliation(s)
- Christina E Wierenga
- VA San Diego Healthcare System, San Diego, CA, USA Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
| | | | - Zvinka Z Zlatar
- VA San Diego Healthcare System, San Diego, CA, USA Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA
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Moore SA, Hallsworth K, Jakovljevic DG, Blamire AM, He J, Ford GA, Rochester L, Trenell MI. Effects of Community Exercise Therapy on Metabolic, Brain, Physical, and Cognitive Function Following Stroke. Neurorehabil Neural Repair 2014; 29:623-35. [DOI: 10.1177/1545968314562116] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Background. Exercise therapy could potentially modify metabolic risk factors and brain physiology alongside improving function post stroke. Objective. To explore the short-term metabolic, brain, cognitive, and functional effects of exercise following stroke. Methods. A total of 40 participants (>50 years, >6 months post stroke, independently mobile) were recruited to a single-blind, parallel, randomized controlled trial of community-based exercise (19 weeks, 3 times/wk, “exercise” group) or stretching (“control” group). Primary outcome measures were glucose control and cerebral blood flow. Secondary outcome measures were cardiorespiratory fitness, blood pressure, lipid profile, body composition, cerebral tissue atrophy and regional brain metabolism, and physical and cognitive function. Results. Exercise did not change glucose control (homeostasis model assessment 1·5 ± 0·8 to 1·5 ± 0·7 vs 1·6 ± 0·8 to 1·7 ± 0·7, P = .97; CI = −0·5 to 0·49). Medial temporal lobe tissue blood flow increased with exercise (38 ± 8 to 42 ± 10 mL/100 g/min; P < .05; CI = 9.0 to 0.1) without any change in gray matter tissue volume. There was no change in medial temporal lobe tissue blood flow in the control group (41 ± 8 to 40 ± 7 mL/100 g/min; P = .13; CI = −3.6 to 6.7) but significant gray matter atrophy. Cardiorespiratory fitness, diastolic blood pressure, high-density lipoprotein cholesterol, physical function, and cognition also improved with exercise. Conclusion. Exercise therapy improves short-term metabolic, brain, physical, and cognitive function, without changes in glucose control following stroke. The long-term impact of exercise on stroke recurrence, cardiovascular health, and disability should now be explored.
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Affiliation(s)
- Sarah A. Moore
- Institute for Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
- Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
| | - Kate Hallsworth
- Institute for Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
- Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
| | - Djordje G. Jakovljevic
- Institute for Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
- Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
| | - Andrew M. Blamire
- Institute for Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Jiabao He
- Institute for Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Gary A. Ford
- Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
| | - Lynn Rochester
- Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
| | - Michael I. Trenell
- Institute for Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
- Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
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Burke MJC, Nelson L, Slade JY, Oakley AE, Khundakar AA, Kalaria RN. Morphometry of the hippocampal microvasculature in post-stroke and age-related dementias. Neuropathol Appl Neurobiol 2014; 40:284-95. [PMID: 24003901 PMCID: PMC4282329 DOI: 10.1111/nan.12085] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 08/29/2013] [Indexed: 12/31/2022]
Abstract
Background Optimal vascular function is vital for prevention of dementia. We hypothesized that elderly post-stroke survivors who preserve cognitive function show unperturbed cerebral microvasculature compared with those who develop dementia. Methods Using stereological spherical probe software, we compared the length density (Lv, cumulative vessel length per unit tissue volume) of hippocampal microvessels in post mortem brain tissue from post-stroke survivors, Alzheimer's disease (AD), vascular dementia (VaD) and normal ageing control subjects. We also assessed microvessel diameters in the same subjects. Microvessels were identified by markers of endothelial cells (glucose transporter 1; GLUT1), basement membrane (collagen IV; COL4) and smooth muscle cell α-actin (SMA). Results We found increased Lv of both GLUT1 and COL4 immunostained microvessels (P < 0.05) in the hippocampal CA1 region of post-stroke demented (PSD) and AD cases compared with post-stroke nondemented (PSND), control and VaD subjects. However, no changes were apparent in the CA2 region. We also noted significant increase in Lv in the entorhinal cortex of AD compared with PSND and PSD subjects. The mean diameter of microvessels was decreased in PSD, compared with PSND, as well as in AD and VaD compared with controls. Cumulative frequency analysis showed PSND subjects to have significantly greater proportion of microvessels with diameters, ranging from 7 to 12 μm. Conclusions An increase in microvascular Lv in AD and PSD suggests either an increase in angiogenesis or the formation of newer microvessel loops in response to cerebral hypoperfusion. The decreased vessel diameters found in AD and VaD suggests increased vasoconstriction in dementia.
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Affiliation(s)
- M J C Burke
- Centre for Brain Ageing and Vitality, Institute for Ageing and Health, Newcastle University, Campus for Ageing & Vitality, Newcastle upon Tyne, UK
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Guo L, Zhang Q, Ding L, Liu K, Ding K, Jiang C, Liu C, Li K, Cui L. Pseudo-continuous arterial spin labeling quantifies cerebral blood flow in patients with acute ischemic stroke and chronic lacunar stroke. Clin Neurol Neurosurg 2014; 125:229-36. [DOI: 10.1016/j.clineuro.2014.08.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 01/25/2014] [Accepted: 08/04/2014] [Indexed: 11/25/2022]
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Ihara M, Kalaria RN. Understanding and preventing the development of post-stroke dementia. Expert Rev Neurother 2014; 14:1067-77. [PMID: 25105544 DOI: 10.1586/14737175.2014.947276] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Post-stroke dementia (PSD) is a clinical entity but it now appears that most of PSD may be categorized as vascular dementia. The well-established relationship between vascular factors and dementia provides a rationale for the implementation of intervention and prevention efforts. Larger primary prevention trials related to lifestyle factors are warranted in association with dementia. Published clinical trials have not been promising and there is meager information on whether PSD can be prevented through the use of pharmacological agents. Control of vascular disease risk and prevention of recurrent strokes are obviously key to reducing the burden of cognitive decline and dementia after stroke. However, modern imaging and analysis techniques will help to elucidate the mechanism of PSD and establish better treatment.
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Affiliation(s)
- Masafumi Ihara
- Department of Stroke and Cerebrovascular Diseases, National Cerebral and Cardiovascular Center, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565, Japan
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Gray matter contamination in arterial spin labeling white matter perfusion measurements in patients with dementia. NEUROIMAGE-CLINICAL 2013; 4:139-44. [PMID: 24371796 PMCID: PMC3871287 DOI: 10.1016/j.nicl.2013.11.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Revised: 11/05/2013] [Accepted: 11/06/2013] [Indexed: 01/28/2023]
Abstract
Introduction White matter (WM) perfusion measurements with arterial spin labeling can be severely contaminated by gray matter (GM) perfusion signal, especially in the elderly. The current study investigates the spatial extent of GM contamination by comparing perfusion signal measured in the WM with signal measured outside the brain. Material and methods Four minute 3T pseudo-continuous arterial spin labeling scans were performed in 41 elderly subjects with cognitive impairment. Outward and inward geodesic distance maps were created, based on dilations and erosions of GM and WM masks. For all outward and inward geodesic distances, the mean CBF was calculated and compared. Results GM contamination was mainly found in the first 3 subcortical WM voxels and had only minor influence on the deep WM signal (distances 4 to 7 voxels). Perfusion signal in the WM was significantly higher than perfusion signal outside the brain, indicating the presence of WM signal. Conclusion These findings indicate that WM perfusion signal can be measured unaffected by GM contamination in elderly patients with cognitive impairment. GM contamination can be avoided by the erosion of WM masks, removing subcortical WM voxels from the analysis. These results should be taken into account when exploring the use of WM perfusion as micro-vascular biomarker. A single slice distance analysis was performed. Perfusion signal in the white matter was compared with signal outside the brain. The application of erosion was compared with removal of partial volume voxels. White matter perfusion signal can be distinguished from gray matter contamination. The erosion of three voxels is warranted to avoid gray matter contamination.
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Zhang Q, Stafford RB, Wang Z, Arnold SE, Wolk DA, Detre JA. Microvascular perfusion based on arterial spin labeled perfusion MRI as a measure of vascular risk in Alzheimer's disease. J Alzheimers Dis 2013; 32:677-87. [PMID: 22886015 DOI: 10.3233/jad-2012-120964] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
There is growing recognition of an interaction between cerebrovascular disease and Alzheimer's disease, but the mechanisms of this interaction remain poorly understood. While macroscopic stroke can clearly produce cognitive deficits and accelerate Alzheimer's disease, the prevalence and implications of microvascular disease in Alzheimer's disease pathogenesis has been harder to define. At present, white matter (WM) lesions, primarily defined as hyperintensities seen on T2-weighted magnetic resonance imaging (MRI), provide the best biomarker of cerebrovascular disease at the microvascular level. However, T2 hyperintensities in WM can also be caused by other mechanisms such as inflammation. Arterial spin labeled (ASL) perfusion MRI provides a noninvasive approach for quantifying cerebral blood flow (CBF). We explored CBF measurements with ASL in AD patients, mild cognitive impairment patients, and an age-matched control group to determine if CBF in gray matter or WM could be correlated with WM lesions, or to stratify patients by microvascular disease severity. In a retrospective sample, we were able to obtain credible measures of WM CBF using ASL MRI and observed trends suggesting that WM CBF may provide a useful biomarker of microvascular disease. Future prospective studies in larger cohorts with optimized ASL MRI protocols will be needed to validate these observations.
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Affiliation(s)
- Quan Zhang
- Center for Functional Neuroimaging, University of Pennsylvania, Philadelphia, PA, USA Department of Radiology, Tianjin Medical University General Hospital, Tianjin, China
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Watts JM, Whitlow CT, Maldjian JA. Clinical applications of arterial spin labeling. NMR IN BIOMEDICINE 2013; 26:892-900. [PMID: 23378178 DOI: 10.1002/nbm.2904] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 10/23/2012] [Accepted: 11/12/2012] [Indexed: 06/01/2023]
Abstract
MR arterial spin labeling is primarily applied as a neuroimaging method to measure cerebral blood flow. As this technique becomes more widely available, a basic understanding of the clinical applications is necessary for optimal utilization in the setting of patient care. This review focuses on the use of arterial spin labeling imaging for the evaluation of cerebrovascular disease, brain tumors and neuropsychiatric illness.
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Affiliation(s)
- Jonathan M Watts
- Wake Forest School of Medicine, Department of Radiology, Winston Salem, NC, USA
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Blood pressure regulation IX: cerebral autoregulation under blood pressure challenges. Eur J Appl Physiol 2013. [PMID: 23737006 DOI: 10.1007/s00421‐013‐2667‐y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Cerebral autoregulation (CA) is integral to the delicate process of maintaining stable cerebral perfusion and brain tissue oxygenation against changes in arterial blood pressure. The last four decades has seen dramatic advances in understanding CA physiology, and the role that CA might play in the causation and progression of disease processes that affect the cerebral circulation such as stroke. However, the translation of these basic scientific advances into clinical practice has been limited by the maintenance of old constructs and because there are persistent gaps in our understanding of how this vital vascular mechanism should be quantified. In this review, we re-evaluate relevant studies that challenge established paradigms about how the cerebral perfusion pressure and blood flow are related. In the context of blood pressure being a major haemodynamic challenge to the cerebral circulation, we conclude that: (1) the physiological properties of CA remain inconclusive, (2) many extant methods for CA characterisation are based on simplistic assumptions that can give rise to misleading interpretations, and (3) robust evaluation of CA requires thorough consideration not only of active vasomotor function, but also the unique properties of the intracranial environment.
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Tzeng YC, Ainslie PN. Blood pressure regulation IX: cerebral autoregulation under blood pressure challenges. Eur J Appl Physiol 2013; 114:545-59. [PMID: 23737006 PMCID: PMC3929776 DOI: 10.1007/s00421-013-2667-y] [Citation(s) in RCA: 153] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 05/21/2013] [Indexed: 12/11/2022]
Abstract
Cerebral autoregulation (CA) is integral to the delicate process of maintaining stable cerebral perfusion and brain tissue oxygenation against changes in arterial blood pressure. The last four decades has seen dramatic advances in understanding CA physiology, and the role that CA might play in the causation and progression of disease processes that affect the cerebral circulation such as stroke. However, the translation of these basic scientific advances into clinical practice has been limited by the maintenance of old constructs and because there are persistent gaps in our understanding of how this vital vascular mechanism should be quantified. In this review, we re-evaluate relevant studies that challenge established paradigms about how the cerebral perfusion pressure and blood flow are related. In the context of blood pressure being a major haemodynamic challenge to the cerebral circulation, we conclude that: (1) the physiological properties of CA remain inconclusive, (2) many extant methods for CA characterisation are based on simplistic assumptions that can give rise to misleading interpretations, and (3) robust evaluation of CA requires thorough consideration not only of active vasomotor function, but also the unique properties of the intracranial environment.
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Affiliation(s)
- Yu-Chieh Tzeng
- Cardiovascular Systems Laboratory, Centre for Translational Physiology, University of Otago, 23A Mein Street, PO Box 7343, Wellington South, New Zealand,
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Tryambake D, He J, Firbank MJ, O'Brien JT, Blamire AM, Ford GA. Intensive blood pressure lowering increases cerebral blood flow in older subjects with hypertension. Hypertension 2013; 61:1309-15. [PMID: 23529166 DOI: 10.1161/hypertensionaha.112.200972] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Hypertension is associated with reduced cerebral blood flow (CBF). Intensive (<130/80 mm Hg) blood pressure (BP) lowering in older people might give greater reduction in cardiovascular risk, but there are concerns that this might produce hypoperfusion which may precipitate falls and possibly stroke. We determined the effect of intensive compared with usual BP lowering on CBF in hypertensive older subjects. Individuals aged >70 years with a history of systolic hypertension on 1 or no BP lowering drugs were recruited from primary care (n=37; age, 75±4 years; systolic BP, >150 mm Hg) and randomized to receive intensive (target BP, <130/80 mm Hg) or usual (target BP, <140/85 mm Hg) BP lowering for 12 weeks, with reviews every 2 weeks. CBF, determined using 3T arterial spin labeling MRI, and 24-hour ambulatory BP were performed at baseline and after 12 weeks of treatment. Baseline BP (ambulatory or in clinic) and baseline gray matter CBF were not significantly different between the groups. After treatment, BP was reduced significantly in both groups but fell more in the intensive group (26/17 versus 15/5 mm Hg; P<0.01). Over the same period, gray matter CBF increased significantly in the intensive group (7±11 mL/min per 100 g; P=0.013) but was unchanged in the usual BP target group (-3±9 mL/min per 100 g; P=0.23); P<0.01 for comparison. Intensive BP lowering in older people with hypertension increases CBF, compared with BP lowering to usual target. These findings suggest hypertension in older people shifts the autoregulatory CBF curve rightward and downward and is reversible with BP lowering.
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Affiliation(s)
- Dinesh Tryambake
- Institute for Ageing and Health, Newcastle University, Stroke Research Group, Level 6, Leazes Wing, Royal Victoria Infirmary, Newcastle upon Tyne NE1 4LP, UK
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Kalaria RN, Akinyemi R, Ihara M. Does vascular pathology contribute to Alzheimer changes? J Neurol Sci 2012; 322:141-7. [PMID: 22884479 DOI: 10.1016/j.jns.2012.07.032] [Citation(s) in RCA: 165] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 07/10/2012] [Accepted: 07/11/2012] [Indexed: 12/21/2022]
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Abstract
BACKGROUND The neurobiological basis of increased risk of dementia in stroke patients is unclear, though there are several related pathological changes, including white matter hyperintensities (WMH), and medial temporal atrophy. Subcortical gray matter structures have also been implicated in dementia resulting from vascular pathology, particularly vascular dementia. This study aimed to investigate the contribution of changes in subcortical gray matter structures to post-stroke dementia (PSD). METHODS T1- and T2-weighted images and T2-weighted fluid-attenuated inversion recovery (FLAIR) images were obtained on a 3-Tesla magnetic resonance (MR) system, in four groups aged over 75 years: post-stroke with dementia (PSD; 8), post-stroke no dementia (PSnoD; 33), Alzheimer's disease (AD; 26) and controls (30). Automated software was used to measure the volume of thalamus, putamen, caudate nucleus, and hippocampus as well as total WMH volume. The number of subcortical lacunes was also counted. RESULTS The number of caudate lacunes was higher in the PSnoD group, compared with AD (p = 0.029) and controls (p = 0.019). The putamen volume was smaller in the stroke and AD groups, when compared with controls. In the whole stroke group, putamen lacunes were correlated with impairment in memory (Rey test; ρ = -0.365; p = 0.031), while WMH and hippocampal volume both correlated with global dysfunction. CONCLUSION Our findings implicate a variety of neurobiological substrates of dementia, such as small vessel disease and Alzheimer pathology, which develop after stroke in an old older population, with a contribution from subcortical brain structures.
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Hendrikse J, Petersen ET, Golay X. Vascular disorders: insights from arterial spin labeling. Neuroimaging Clin N Am 2012; 22:259-69, x-xi. [PMID: 22548931 DOI: 10.1016/j.nic.2012.02.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The introduction of high-field magnetic imaging (≥3 T) has made noninvasive arterial spin labeling (ASL) a realistic clinical option for perfusion assessment in vascular disorders. Combined with the advances provided by territorial imaging of individual intracerebral arteries and the measurement of vascular reactivity, ASL is a powerful tool for evaluating vascular diseases of the brain. This article evaluates its use in chronic cerebrovascular disease, stroke, moyamoya disease, and arteriovenous malformation, but ASL may also find applications in related diseases such as vascular dementia.
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Affiliation(s)
- Jeroen Hendrikse
- Department of Radiology, University Medical Center Utrecht, Room E01.132, PO Box 85500, 3508 GA Utrecht, The Netherlands.
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Deramecourt V, Slade JY, Oakley AE, Perry RH, Ince PG, Maurage CA, Kalaria RN. Staging and natural history of cerebrovascular pathology in dementia. Neurology 2012; 78:1043-50. [PMID: 22377814 DOI: 10.1212/wnl.0b013e31824e8e7f] [Citation(s) in RCA: 200] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
OBJECTIVE Most pathologic studies indicate that significant vascular changes are found in the majority of elderly persons, either alone or in association with neurodegenerative processes such as Alzheimer disease (AD) or dementia with Lewy bodies (DLB). Cumulative burden of cerebrovascular lesions can explain cognitive decline described as vascular cognitive impairment, but because there is a lack of consensus in the best way to quantify vascular pathology, the relationship between cognitive decline and cerebrovascular disease remains uncertain. We developed a rating scheme for cerebrovascular lesions using postmortem brains from patients with dementia from 2 European tertiary care memory clinics. METHODS A total of 135 brains with a neuropathologic diagnosis of vascular dementia (VaD) (n = 26), AD + VaD (n = 39), DLB + VaD (n = 21), AD + DLB + VaD (n = 9), AD (n = 19), and DLB (n = 21) were investigated in this study. Cerebrovascular lesions were rated on large sections from the hippocampus, the temporal lobe, the frontal lobe, and basal ganglia. RESULTS In patients with dementia, vessel wall modifications such as arteriolosclerosis or amyloid angiopathy are the most common and presumably the earliest changes. Modifications in perivascular spaces and myelin loss are the next most common. Lacunar or regional infarcts may occur as a consequence of an independent process or in the final phase of small vessel diseases. CONCLUSION A staging system based on this conceptual model of cerebrovascular pathology could enable the neuropathologic quantification of the cerebrovascular burden in dementia. Further studies are needed to determine whether this system can be used in large-scale studies to understand clinical-cerebrovascular pathologic correlations.
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Affiliation(s)
- V Deramecourt
- Institute for Ageing and Health, Campus for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, UK
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Allan LM, Rowan EN, Firbank MJ, Thomas AJ, Parry SW, Polvikoski TM, O'Brien JT, Kalaria RN. Long term incidence of dementia, predictors of mortality and pathological diagnosis in older stroke survivors. Brain 2012; 134:3716-27. [PMID: 22171356 PMCID: PMC3235558 DOI: 10.1093/brain/awr273] [Citation(s) in RCA: 158] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Greater understanding of the risk factors and mechanisms of incident dementia in stroke survivors is needed for prevention and management. There is limited information on the long-term consequences and forms of incident dementia in older stroke survivors. We recruited 355 patients aged >75 years from hospital-based stroke registers into a longitudinal study 3 months after stroke. At baseline none of the patients had dementia. Patients were genotyped for apolipoprotein E and assessed annually for cognition and development of incident dementia over up to 8 years of follow-up. The effect of baseline vascular risk factors upon incidence of dementia and mortality were estimated by Cox proportional regression analyses adjusted for age and gender. Standard neuropathological examination was performed to diagnose the first 50 cases that came to autopsy. We found that the median survival from the date of the index stroke was 6.72 years (95% confidence intervals: 6.38–7.05). During the follow-up of a mean time of 3.79 years, 23.9% of subjects were known to have developed dementia and 76.1% remained alive without dementia or died without dementia. The incidence of delayed dementia was calculated to be 6.32 cases per 100 person years whereas that for death or dementia was 8.62. Univariate and multivariate regression analyses showed that the most robust predictors of dementia included low (1.5 standard deviations below age-matched control group) baseline Cambridge Cognitive Examination executive function and memory scores, Geriatric Depression Scale score and three or more cardiovascular risk factors. Autopsy findings suggested that remarkably ≥75% of the demented stroke survivors met the current criteria for vascular dementia. Demented subjects tended to exhibit marginally greater neurofibrillary pathology including tauopathy and Lewy bodies and microinfarcts than non-demented survivors. Despite initial improvements in cognition following stroke in older stroke survivors, risk of progression to delayed dementia after stroke is substantial, but is related to the presence of vascular risk factors. Careful monitoring and treatment of modifiable vascular risk factors may be of benefit in preventing post-stroke dementia in the general population.
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Affiliation(s)
- Louise M Allan
- Institute for Ageing and Health, Newcastle University, Wolfson Research Centre, Campus for Ageing and Vitality, Newcastle upon Tyne, NE4 5PL, UK.
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Gemmell E, Bosomworth H, Allan L, Hall R, Khundakar A, Oakley AE, Deramecourt V, Polvikoski TM, O'Brien JT, Kalaria RN. Hippocampal neuronal atrophy and cognitive function in delayed poststroke and aging-related dementias. Stroke 2011; 43:808-14. [PMID: 22207507 DOI: 10.1161/strokeaha.111.636498] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND AND PURPOSE We have previously shown delayed poststroke dementia in elderly (≥75 years old) stroke survivors is associated with medial temporal lobe atrophy; however, the basis of the structural and functional changes is unknown. METHODS Using 3-dimensional stereological methods, we quantified hippocampal pyramidal neuronal volumes and densities in a total of 95 postmortem samples from demented and nondemented poststroke survivors within our prospective Cognitive Function after Stroke study and subjects pathologically diagnosed with vascular dementia, Alzheimer disease, and mixed Alzheimer disease and vascular dementia syndrome. RESULTS Hippocampal CA1 but not CA2 subfield neuron density was affected in poststroke, Alzheimer disease, vascular dementia, and mixed dementia groups relative to control subjects (P<0.05). Neuronal volume was reduced in the poststroke dementia relative to poststroke nondemented group in both CA1 and CA2, although there were no apparent differences in neuronal density. Poststroke nondemented neuronal volumes were similar to control subjects but greater than in all dementias (P<0.05). Neuronal volumes positively correlated with global cognitive function and memory function in both CA1 and CA2 in poststroke subjects (P<0.01). Degrees of neuronal atrophy and loss were similar in the poststroke dementia and vascular dementia groups. However, in the entorhinal cortex layer V, neuronal volumes were only impaired in the mixed and Alzheimer disease groups (P<0.05). CONCLUSIONS Our results suggest hippocampal neuronal atrophy is an important substrate for dementia in both cerebrovascular and neurodegenerative disease.
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Affiliation(s)
- Elizabeth Gemmell
- Centre for Brain Ageing and Vitality, Institute for Ageing and Health, Newcastle University, Campus for Ageing & Vitality, Newcastle upon Tyne, UK
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