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Khan F, Qiu H. Amyloid-β: A potential mediator of aging-related vascular pathologies. Vascul Pharmacol 2023; 152:107213. [PMID: 37625763 DOI: 10.1016/j.vph.2023.107213] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 08/09/2023] [Accepted: 08/21/2023] [Indexed: 08/27/2023]
Abstract
Aging is one of the most promising risk factors for vascular diseases, however, the precise mechanisms mediating aging-related pathologies are not fully understood. Amyloid beta (Aβ), a peptide produced by the proteolytic processing of amyloid precursor protein (APP), is known as a key mediator of brain damage involved in the pathogenesis of Alzheimer's disease (AD). Recently, it was found that the accumulation of Aβ in the vascular wall is linked to a range of aging-related vascular pathologies, indicating a potential role of Aβ in the pathogenesis of aging-associated vascular diseases. In the present review, we have updated the molecular regulation of Aβ in vascular cells and tissues, summarized the relevance of the Aβ deposition with vascular aging and diseases, and the role of Aβ dysregulation in aging-associated vascular pathologies, including the impaired vascular response, endothelial dysfunction, oxidative stress, and inflammation. This review will provide advanced information in understanding aging-related vascular pathologies and a new avenue to explore therapeutic targets.
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Affiliation(s)
- Fazlullah Khan
- Translational Cardiovascular Research Center, College of Medicine-Phoenix, The University of Arizona, Phoenix 85004, AZ, USA
| | - Hongyu Qiu
- Translational Cardiovascular Research Center, Department of Internal Medicine, College of Medicine-Phoenix, The University of Arizona, Phoenix 85004, AZ, USA.
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2
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Ni R. Magnetic Resonance Imaging in Animal Models of Alzheimer's Disease Amyloidosis. Int J Mol Sci 2021; 22:12768. [PMID: 34884573 PMCID: PMC8657987 DOI: 10.3390/ijms222312768] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 11/18/2021] [Accepted: 11/23/2021] [Indexed: 02/07/2023] Open
Abstract
Amyloid-beta (Aβ) plays an important role in the pathogenesis of Alzheimer's disease. Aberrant Aβ accumulation induces neuroinflammation, cerebrovascular alterations, and synaptic deficits, leading to cognitive impairment. Animal models recapitulating the Aβ pathology, such as transgenic, knock-in mouse and rat models, have facilitated the understanding of disease mechanisms and the development of therapeutics targeting Aβ. There is a rapid advance in high-field MRI in small animals. Versatile high-field magnetic resonance imaging (MRI) sequences, such as diffusion tensor imaging, arterial spin labeling, resting-state functional MRI, anatomical MRI, and MR spectroscopy, as well as contrast agents, have been developed for preclinical imaging in animal models. These tools have enabled high-resolution in vivo structural, functional, and molecular readouts with a whole-brain field of view. MRI has been used to visualize non-invasively the Aβ deposits, synaptic deficits, regional brain atrophy, impairment in white matter integrity, functional connectivity, and cerebrovascular and glymphatic system in animal models of Alzheimer's disease amyloidosis. Many of the readouts are translational toward clinical MRI applications in patients with Alzheimer's disease. In this review, we summarize the recent advances in MRI for visualizing the pathophysiology in amyloidosis animal models. We discuss the outstanding challenges in brain imaging using MRI in small animals and propose future outlook in visualizing Aβ-related alterations in the brains of animal models.
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Affiliation(s)
- Ruiqing Ni
- Institute for Biomedical Engineering, ETH Zurich & University of Zurich, 8093 Zurich, Switzerland;
- Institute for Regenerative Medicine, University of Zurich, 8952 Zurich, Switzerland
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3
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Meier IB, Lao PJ, Gietl A, Vorburger RS, Gutierrez J, Holland CM, Guttmann CRG, Meier DS, Buck A, Nitsch RM, Hock C, Unschuld PG, Brickman AM. Brain areas with normatively greater cerebral perfusion in early life may be more susceptible to beta amyloid deposition in late life. ACTA ACUST UNITED AC 2020; 1. [PMID: 34368788 PMCID: PMC8340623 DOI: 10.1016/j.cccb.2020.100001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Background The amyloid cascade hypothesis characterizes the stereotyped progression of pathological changes in Alzheimer's disease (AD) beginning with beta amyloid deposition, but does not address the reasons for amyloid deposition. Brain areas with relatively higher neuronal activity, metabolic demand, and production of reactive oxygen species in earlier life may have higher beta amyloid deposition in later life. The aim of this study was to investigate early life patterns of perfusion and late life patterns of amyloid deposition to determine the extent to which normative cerebral perfusion predisposes specific regions to future beta amyloid deposition. Materials and Methods One hundred twenty-eight healthy, older human subjects (age: 56-87 years old; 44% women) underwent positron emission tomography (PET) imaging with [11C]PiB for measures of amyloid burden. Cerebral perfusion maps derived from 47 healthy younger adults (age: 22-49; 47%) who had undergone single photon emission computed tomography (SPECT) imaging, were averaged to create a normative template, representative of young, healthy adults. Perfusion and amyloid measures were investigated in 31 cortical regions from the Hammers atlas. We examined the spatial relationship between normative perfusion patterns and amyloid pathophysiology. Results The pattern of increasing perfusion (temporal lobe < parietal lobe < frontal lobe < insula/cingulate gyrus < occipital lobe; F(4,26) = 7.8, p = 0.0003) in young, healthy adults was not exactly identical to but approximated the pattern of increasing amyloid burden (temporal lobe < occipital lobe < frontal lobe < parietal lobe < insula/cingulate gyrus; F(4,26) = 5.0, p = 0.004) in older adults. However, investigating subregions within cortical lobes provided consistent agreement between ranked normative perfusion patterns and expected Thal staging of amyloid progression in AD (Spearman r = 0.39, p = 0.03). Conclusion Our findings suggest that brain areas with normatively greater perfusion may be more susceptible to amyloid deposition in later life, possibly due to higher metabolic demand, and associated levels of oxidative stress and inflammation.
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Affiliation(s)
- Irene B Meier
- Institute for Regenerative Medicine IREM, University of Zurich, 8952 Zurich, Switzerland.,Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Patrick J Lao
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Anton Gietl
- Institute for Regenerative Medicine IREM, University of Zurich, 8952 Zurich, Switzerland
| | - Robert S Vorburger
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - José Gutierrez
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | | | - Charles R G Guttmann
- Center for Neurological Imaging, Brigham and Women's Hospital, Harvard Medical School, Boston MA 02215, USA
| | - Dominik S Meier
- Center for Neurological Imaging, Brigham and Women's Hospital, Harvard Medical School, Boston MA 02215, USA
| | - Alfred Buck
- University Hospital Zurich, Clinic for Nuclear Medicine, Zurich, 8091, Switzerland
| | - Roger M Nitsch
- Institute for Regenerative Medicine IREM, University of Zurich, 8952 Zurich, Switzerland.,Neurimmune, Schlieren, Switzerland
| | - Christoph Hock
- Institute for Regenerative Medicine IREM, University of Zurich, 8952 Zurich, Switzerland.,Neurimmune, Schlieren, Switzerland
| | - Paul G Unschuld
- Institute for Regenerative Medicine IREM, University of Zurich, 8952 Zurich, Switzerland
| | - Adam M Brickman
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.,Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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4
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Early functional connectivity deficits and progressive microstructural alterations in the TgF344-AD rat model of Alzheimer’s Disease: A longitudinal MRI study. Neurobiol Dis 2019; 124:93-107. [DOI: 10.1016/j.nbd.2018.11.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 11/05/2018] [Accepted: 11/12/2018] [Indexed: 01/05/2023] Open
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5
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Anckaerts C, Blockx I, Summer P, Michael J, Hamaide J, Kreutzer C, Boutin H, Couillard-Després S, Verhoye M, Van der Linden A. Early functional connectivity deficits and progressive microstructural alterations in the TgF344-AD rat model of Alzheimer’s Disease: A longitudinal MRI study. Neurobiol Dis 2019. [DOI: 10.1016/j.nbd.2018.11.010 and 21=21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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6
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Ni R, Kindler DR, Waag R, Rouault M, Ravikumar P, Nitsch R, Rudin M, Camici GG, Liberale L, Kulic L, Klohs J. fMRI Reveals Mitigation of Cerebrovascular Dysfunction by Bradykinin Receptors 1 and 2 Inhibitor Noscapine in a Mouse Model of Cerebral Amyloidosis. Front Aging Neurosci 2019; 11:27. [PMID: 30890928 PMCID: PMC6413713 DOI: 10.3389/fnagi.2019.00027] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 01/30/2019] [Indexed: 11/28/2022] Open
Abstract
Functional magnetic resonance imaging (fMRI) techniques can be used to assess cerebrovascular dysfunction in Alzheimer’s disease, an important and early contributor to pathology. We hypothesized that bradykinin receptor inhibition alleviates the vascular dysfunction in a transgenic arcAβ mouse model of cerebral amyloidosis and that fMRI techniques can be used to monitor the treatment response. Transgenic arcAβ mice, and non-transgenic littermates of 14 months-of-age were either treated with the bradykinin receptors 1 and 2 blocker noscapine or received normal drinking water as control over 3 months (n = 8–11/group) and all mice were assessed using fMRI at the end of the treatment period. Perfusion MRI using an arterial spin labeling technique showed regional hypoperfusion in arcAβ compared to non-transgenic controls, which was alleviated by noscapine treatment. Similarly, measuring cerebral blood volume changes upon pharmacological stimulation using vessel dilator acetazolamide revealed recovery of regional impairment of cerebral vascular reactivity in arcAβ mice upon noscapine treatment. In addition, we assessed with immunohistochemistry beta-amyloid (Aβ) and inflammation levels in brain sections. Immunohistological stainings for Aβ deposition (6E10) and related microgliosis (Iba1) in the cortex and hippocampus were found comparable between noscapine-treated and untreated arcAβ mice. In addition, levels of soluble and insoluble Aβ38, Aβ40, Aβ42 were found to be similar in brain tissue homogenates of noscapine-treated and untreated arcAβ mice using electro-chemiluminescent based immunoassay. In summary, bradykinin receptors blockade recovered cerebral vascular dysfunction in a mouse model of cerebral amyloidosis. fMRI methods revealed the functional deficit in disease condition and were useful tools to monitor the treatment response.
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Affiliation(s)
- Ruiqing Ni
- Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zürich, Switzerland.,Zurich Neuroscience Center, Zürich, Switzerland
| | - Diana Rita Kindler
- Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zürich, Switzerland
| | - Rebecca Waag
- Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zürich, Switzerland
| | - Marie Rouault
- Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zürich, Switzerland.,Zurich Neuroscience Center, Zürich, Switzerland
| | - Priyanka Ravikumar
- Institute for Regenerative Medicine, University of Zurich, Zürich, Switzerland
| | - Roger Nitsch
- Institute for Regenerative Medicine, University of Zurich, Zürich, Switzerland
| | - Markus Rudin
- Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zürich, Switzerland
| | - Giovanni G Camici
- Zurich Neuroscience Center, Zürich, Switzerland.,Center for Molecular Cardiology, University of Zurich, Zürich, Switzerland
| | - Luca Liberale
- Institute for Regenerative Medicine, University of Zurich, Zürich, Switzerland.,Department of Internal Medicine, University of Genoa, Genoa, Italy
| | - Luka Kulic
- Zurich Neuroscience Center, Zürich, Switzerland.,Institute for Regenerative Medicine, University of Zurich, Zürich, Switzerland
| | - Jan Klohs
- Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zürich, Switzerland.,Zurich Neuroscience Center, Zürich, Switzerland
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7
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Govaerts K, Lechat B, Struys T, Kremer A, Borghgraef P, Van Leuven F, Himmelreich U, Dresselaers T. Longitudinal assessment of cerebral perfusion and vascular response to hypoventilation in a bigenic mouse model of Alzheimer's disease with amyloid and tau pathology. NMR IN BIOMEDICINE 2019; 32:e4037. [PMID: 30489666 DOI: 10.1002/nbm.4037] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 10/22/2018] [Accepted: 10/23/2018] [Indexed: 06/09/2023]
Abstract
Alzheimer's disease is the most common neurodegenerative disease, and many patients also present with vascular dysfunction. In this study, we aimed to assess cerebral blood flow (CBF) and cerebrovascular response (CVR) as early, pre-symptomatic (3 months of age), imaging markers in a bigenic model of Alzheimer's disease (APP.V717IxTau.P301L, biAT) and in the monogenic parental strains. We further developed our previously published combination of pulsed arterial spin labeling perfusion MRI and hypo-ventilation paradigm, which allows weaning of the mice from the ventilator. Furthermore, the commonly used isoflurane anesthesia induces vasodilation and is thereby inherently a vascular challenge. We therefore assessed perfusion differences in the mouse models under free-breathing isoflurane conditions. We report (i) that we can determine CBF and hypoventilation-based CVR under ketamine/midazolam anesthesia and wean mice from the ventilator, making it a valuable tool for assessment of CBF and CVR in mice, (ii) that biAT mice exhibit lower cortical CBF than wild-type mice at age 3 months, (iii) that CVR was increased in both biAT and APP.V717I mice but not in Tau.P301L mice, identifying the APP genotype as a strong influencer of brain CVR and (iv) that perfusion differences at baseline are masked by the widely used isoflurane anesthesia.
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Affiliation(s)
- Kristof Govaerts
- Biomedical MRI/MoSAIC, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | - Benoit Lechat
- LEGTEGG, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Tom Struys
- Morphology Research Group, Biomedical Research Institute, Universiteit Hasselt, Hasselt, Belgium
| | - Anna Kremer
- LEGTEGG, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Peter Borghgraef
- LEGTEGG, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Fred Van Leuven
- LEGTEGG, Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Uwe Himmelreich
- Biomedical MRI/MoSAIC, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
| | - Tom Dresselaers
- Biomedical MRI/MoSAIC, Department of Imaging and Pathology, KU Leuven, Leuven, Belgium
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8
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Ni R, Rudin M, Klohs J. Cortical hypoperfusion and reduced cerebral metabolic rate of oxygen in the arcAβ mouse model of Alzheimer's disease. PHOTOACOUSTICS 2018; 10:38-47. [PMID: 29682448 PMCID: PMC5909030 DOI: 10.1016/j.pacs.2018.04.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 02/14/2018] [Accepted: 04/03/2018] [Indexed: 05/18/2023]
Abstract
The effect of cerebral amyloidosis on cerebral hemodynamics was investigated with photoacoustic tomography (PAT) and magnetic resonance imaging (MRI). First, the sensitivity and robustness of PAT for deriving metrics of vascular and tissue oxygenation in the murine brain was assessed in wild-type mice with a hyperoxia-normoxia challenge. Secondly, cerebral oxygenation was assessed in young and aged arcAβ mice and wild-type controls with PAT, while cerebral blood flow (CBF) was determined by perfusion MRI. The investigations revealed that PAT can sensitively and robustly detect physiological changes in vascular and tissue oxygenation. An advanced stage of cerebral amyloidosis in arcAβ mice is accompanied by a decreases in cortical CBF and the cerebral metabolic rate of oxygen (CMRO2), as oxygen extraction fraction (OEF) has been found unaffected. Thus, PAT constitutes a robust non-invasive tool for deriving metrics of tissue oxygenation, extraction and metabolism in the mouse brain under physiological and disease states.
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Affiliation(s)
- Ruiqing Ni
- Institute for Biomedical Engineering, University of Zurich & ETH Zurich, 8093 Zurich, Switzerland
| | - Markus Rudin
- Institute for Biomedical Engineering, University of Zurich & ETH Zurich, 8093 Zurich, Switzerland
- Institute of Pharmacology and Toxicology, University of Zurich, 8008 Zurich, Switzerland
| | - Jan Klohs
- Institute for Biomedical Engineering, University of Zurich & ETH Zurich, 8093 Zurich, Switzerland
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9
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Asaad M, Lee JH. A guide to using functional magnetic resonance imaging to study Alzheimer's disease in animal models. Dis Model Mech 2018; 11:dmm031724. [PMID: 29784664 PMCID: PMC5992611 DOI: 10.1242/dmm.031724] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Alzheimer's disease is a leading healthcare challenge facing our society today. Functional magnetic resonance imaging (fMRI) of the brain has played an important role in our efforts to understand how Alzheimer's disease alters brain function. Using fMRI in animal models of Alzheimer's disease has the potential to provide us with a more comprehensive understanding of the observations made in human clinical fMRI studies. However, using fMRI in animal models of Alzheimer's disease presents some unique challenges. Here, we highlight some of these challenges and discuss potential solutions for researchers interested in performing fMRI in animal models. First, we briefly summarize our current understanding of Alzheimer's disease from a mechanistic standpoint. We then overview the wide array of animal models available for studying this disease and how to choose the most appropriate model to study, depending on which aspects of the condition researchers seek to investigate. Finally, we discuss the contributions of fMRI to our understanding of Alzheimer's disease and the issues to consider when designing fMRI studies for animal models, such as differences in brain activity based on anesthetic choice and ways to interrogate more specific questions in rodents beyond those that can be addressed in humans. The goal of this article is to provide information on the utility of fMRI, and approaches to consider when using fMRI, for studies of Alzheimer's disease in animal models.
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Affiliation(s)
- Mazen Asaad
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
| | - Jin Hyung Lee
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA 94305, USA
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
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10
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Animal models of cerebral amyloid angiopathy. Clin Sci (Lond) 2017; 131:2469-2488. [PMID: 28963121 DOI: 10.1042/cs20170033] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Revised: 08/24/2017] [Accepted: 08/29/2017] [Indexed: 02/04/2023]
Abstract
Cerebral amyloid angiopathy (CAA), due to vascular amyloid β (Aβ) deposition, is a risk factor for intracerebral haemorrhage and dementia. CAA can occur in sporadic or rare hereditary forms, and is almost invariably associated with Alzheimer's disease (AD). Experimental (animal) models are of great interest in studying mechanisms and potential treatments for CAA. Naturally occurring animal models of CAA exist, including cats, dogs and non-human primates, which can be used for longitudinal studies. However, due to ethical considerations and low throughput of these models, other animal models are more favourable for research. In the past two decades, a variety of transgenic mouse models expressing the human Aβ precursor protein (APP) has been developed. Many of these mouse models develop CAA in addition to senile plaques, whereas some of these models were generated specifically to study CAA. In addition, other animal models make use of a second stimulus, such as hypoperfusion or hyperhomocysteinemia (HHcy), to accelerate CAA. In this manuscript, we provide a comprehensive review of existing animal models for CAA, which can aid in understanding the pathophysiology of CAA and explore the response to potential therapies.
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11
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Di Marco LY, Farkas E, Martin C, Venneri A, Frangi AF. Is Vasomotion in Cerebral Arteries Impaired in Alzheimer's Disease? J Alzheimers Dis 2016; 46:35-53. [PMID: 25720414 PMCID: PMC4878307 DOI: 10.3233/jad-142976] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A substantial body of evidence supports the hypothesis of a vascular component in the pathogenesis of Alzheimer’s disease (AD). Cerebral hypoperfusion and blood-brain barrier dysfunction have been indicated as key elements of this pathway. Cerebral amyloid angiopathy (CAA) is a cerebrovascular disorder, frequent in AD, characterized by the accumulation of amyloid-β (Aβ) peptide in cerebral blood vessel walls. CAA is associated with loss of vascular integrity, resulting in impaired regulation of cerebral circulation, and increased susceptibility to cerebral ischemia, microhemorrhages, and white matter damage. Vasomotion— the spontaneous rhythmic modulation of arterial diameter, typically observed in arteries/arterioles in various vascular beds including the brain— is thought to participate in tissue perfusion and oxygen delivery regulation. Vasomotion is impaired in adverse conditions such as hypoperfusion and hypoxia. The perivascular and glymphatic pathways of Aβ clearance are thought to be driven by the systolic pulse. Vasomotion produces diameter changes of comparable amplitude, however at lower rates, and could contribute to these mechanisms of Aβ clearance. In spite of potential clinical interest, studies addressing cerebral vasomotion in the context of AD/CAA are limited. This study reviews the current literature on vasomotion, and hypothesizes potential paths implicating impaired cerebral vasomotion in AD/CAA. Aβ and oxidative stress cause vascular tone dysregulation through direct effects on vascular cells, and indirect effects mediated by impaired neurovascular coupling. Vascular tone dysregulation is further aggravated by cholinergic deficit and results in depressed cerebrovascular reactivity and (possibly) impaired vasomotion, aggravating regional hypoperfusion and promoting further Aβ and oxidative stress accumulation.
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Affiliation(s)
- Luigi Yuri Di Marco
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, UK
| | - Eszter Farkas
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Chris Martin
- Department of Psychology, University of Sheffield, Sheffield, UK
| | - Annalena Venneri
- Department of Neuroscience, University of Sheffield, Sheffield, UK.,IRCCS, Fondazione Ospedale S. Camillo, Venice, Italy
| | - Alejandro F Frangi
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, UK
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12
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Grandjean J, Derungs R, Kulic L, Welt T, Henkelman M, Nitsch RM, Rudin M. Complex interplay between brain function and structure during cerebral amyloidosis in APP transgenic mouse strains revealed by multi-parametric MRI comparison. Neuroimage 2016; 134:1-11. [PMID: 27033685 DOI: 10.1016/j.neuroimage.2016.03.042] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 03/11/2016] [Accepted: 03/17/2016] [Indexed: 11/28/2022] Open
Abstract
Alzheimer's disease is a fatal neurodegenerative disorder affecting the aging population. Neuroimaging methods, in particular magnetic resonance imaging (MRI), have helped reveal alterations in the brain structure, metabolism, and function of patients and in groups at risk of developing AD, yet the nature of these alterations is poorly understood. Neuroimaging in mice is attractive for investigating mechanisms underlying functional and structural changes associated with AD pathology. Several preclinical murine models of AD have been generated based on transgenic insertion of human mutated APP genes. Depending on the specific mutations, mouse strains express different aspects of amyloid pathology, e.g. intracellular amyloid-β (Aβ) aggregates, parenchymal plaques, or cerebral amyloid angiopathy. We have applied multi-parametric MRI in three transgenic mouse lines to compare changes in brain function with resting-state fMRI and structure with diffusion tensor imaging and high resolution anatomical imaging. E22ΔAβ developing intracellular Aβ aggregates did not present functional or structural alterations compared to their wild-type littermates. PSAPP mice displaying parenchymal amyloid plaques displayed mild functional changes within the supplementary and barrel field cortices, and increased isocortical volume relative to controls. Extensive reduction in functional connectivity in the sensory-motor cortices and within the default mode network, as well as local volume increase in the midbrain relative to wild-type have been observed in ArcAβ mice bearing intracellular Aβ aggregates as well as parenchymal and vascular amyloid deposits. Patterns of functional and structural changes appear to be strain-specific and not directly related to amyloid deposition.
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Affiliation(s)
- Joanes Grandjean
- Institute for Biomedical Engineering, University and ETH Zürich, Zürich, Switzerland
| | - Rebecca Derungs
- Center for Neuroscience Research, University and ETH Zürich, Zürich, Switzerland; Division of Psychiatry Research, University of Zürich, Zürich, Switzerland
| | - Luka Kulic
- Center for Neuroscience Research, University and ETH Zürich, Zürich, Switzerland; Division of Psychiatry Research, University of Zürich, Zürich, Switzerland
| | - Tobias Welt
- Center for Neuroscience Research, University and ETH Zürich, Zürich, Switzerland; Division of Psychiatry Research, University of Zürich, Zürich, Switzerland
| | - Mark Henkelman
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Canada
| | - Roger M Nitsch
- Center for Neuroscience Research, University and ETH Zürich, Zürich, Switzerland; Division of Psychiatry Research, University of Zürich, Zürich, Switzerland
| | - Markus Rudin
- Institute for Biomedical Engineering, University and ETH Zürich, Zürich, Switzerland; Center for Neuroscience Research, University and ETH Zürich, Zürich, Switzerland; Institute of Pharmacology and Toxicology, University of Zürich, Zürich, Switzerland.
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13
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Marowsky A, Haenel K, Bockamp E, Heck R, Rutishauser S, Mule N, Kindler D, Rudin M, Arand M. Genetic enhancement of microsomal epoxide hydrolase improves metabolic detoxification but impairs cerebral blood flow regulation. Arch Toxicol 2016; 90:3017-3027. [PMID: 26838043 PMCID: PMC5104800 DOI: 10.1007/s00204-016-1666-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 01/06/2016] [Indexed: 01/05/2023]
Abstract
Microsomal epoxide hydrolase (mEH) is a detoxifying enzyme for xenobiotic compounds. Enzymatic activity of mEH can be greatly increased by a point mutation, leading to an E404D amino acid exchange in its catalytic triad. Surprisingly, this variant is not found in any vertebrate species, despite the obvious advantage of accelerated detoxification. We hypothesized that this evolutionary avoidance is due to the fact that the mEH plays a dualistic role in detoxification and control of endogenous vascular signaling molecules. To test this, we generated mEH E404D mice and assessed them for detoxification capacity and vascular dynamics. In liver microsomes from these mice, turnover of the xenobiotic compound phenanthrene-9,10-oxide was four times faster compared to WT liver microsomes, confirming accelerated detoxification. mEH E404D animals also showed faster metabolization of a specific class of endogenous eicosanoids, arachidonic acid-derived epoxyeicosatrienoic acids (EETs) to dihydroxyeicosatrienoic acids (DHETs). Significantly higher DHETs/EETs ratios were found in mEH E404D liver, urine, plasma, brain and cerebral endothelial cells compared to WT controls, suggesting a broad impact of the mEH mutant on endogenous EETs metabolism. Because EETs are strong vasodilators in cerebral vasculature, hemodynamics were assessed in mEH E404D and WT cerebral cortex and hippocampus using cerebral blood volume (CBV)-based functional magnetic resonance imaging (fMRI). Basal CBV0 levels were similar between mEH E404D and control mice in both brain areas. But vascular reactivity and vasodilation in response to the vasodilatory drug acetazolamide were reduced in mEH E404D forebrain compared to WT controls by factor 3 and 2.6, respectively. These results demonstrate a critical role for mEH E404D in vasodynamics and suggest that deregulation of endogenous signaling pathways is the undesirable gain of function associated with the E404D variant.
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Affiliation(s)
- Anne Marowsky
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Karen Haenel
- Institute of Complex Systems (ICS-6), Research Center Julich, Wilhelm-Johnen-Straße, 52425, Julich, Germany
| | - Ernesto Bockamp
- Institute of Translational Immunology, University of Mainz, Obere Zahlbacherstrasse 63, 55131, Mainz, Germany
| | - Rosario Heck
- Institute of Translational Immunology, University of Mainz, Obere Zahlbacherstrasse 63, 55131, Mainz, Germany
| | - Sibylle Rutishauser
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Nandkishor Mule
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Diana Kindler
- Institute for Biomedical Engineering, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093, Zurich, Switzerland
| | - Markus Rudin
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.,Institute for Biomedical Engineering, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093, Zurich, Switzerland
| | - Michael Arand
- Institute of Pharmacology and Toxicology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
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Early alterations in functional connectivity and white matter structure in a transgenic mouse model of cerebral amyloidosis. J Neurosci 2015; 34:13780-9. [PMID: 25297104 DOI: 10.1523/jneurosci.4762-13.2014] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Impairment of brain functional connectivity (FC) is thought to be an early event occurring in diseases with cerebral amyloidosis, such as Alzheimer's disease. Regions sustaining altered functional networks have been shown to colocalize with regions marked with amyloid plaques burden suggesting a strong link between FC and amyloidosis. Whether the decline in FC precedes amyloid plaque deposition or is a consequence thereof is currently unknown. The sequence of events during early stages of the disease is difficult to capture in humans due to the difficulties in providing an early diagnosis and also in view of the heterogeneity among patients. Transgenic mouse lines overexpressing amyloid precursor proteins develop cerebral amyloidosis and constitute an attractive model system for studying the relationship between plaque and functional changes. In this study, ArcAβ transgenic and wild-type mice were imaged using resting-state fMRI methods across their life-span in a cross-sectional design to analyze changes in FC in relation to the pathology. Transgenic mice show compromised development of FC during the first months of postnatal life compared with wild-type animals, resulting in functional impairments that affect in particular the sensory-motor cortex already in preplaque stage. These functional alterations were accompanied by structural changes as reflected by reduced fractional anisotropy values, as derived from diffusion tensor imaging. Our results suggest cerebral amyloidosis in mice is preceded by impairment of neuronal networks and white matter structures. FC analysis in mice is an attractive tool for studying the implications of impaired neuronal networks in models of cerebral amyloid pathology.
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15
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McDade E, Kim A, James J, Sheu LK, Kuan DCH, Minhas D, Gianaros PJ, Ikonomovic S, Lopez O, Snitz B, Price J, Becker J, Mathis C, Klunk W. Cerebral perfusion alterations and cerebral amyloid in autosomal dominant Alzheimer disease. Neurology 2014; 83:710-7. [PMID: 25031286 DOI: 10.1212/wnl.0000000000000721] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To evaluate alterations in cerebral blood flow (CBF) using arterial spin-labeled MRI in autosomal dominant Alzheimer disease (ADAD) mutation carriers (MCs) in relation to cerebral amyloid and compared with age-matched healthy controls. BACKGROUND Recent work has identified alterations in CBF in elderly subjects with mild cognitive impairment and Alzheimer dementia using MRI. However, similar studies are lacking in ADAD. Subjects with ADAD are generally free of significant vascular disease and offer the opportunity to measure CBF early in the pathologic process before significant symptom onset when unique markers might be identified. METHODS Fourteen MCs (presenilin-1 and amyloid beta precursor protein) (Clinical Dementia Rating [CDR] 0 = 9, CDR 0.5 = 4, CDR 1 = 1) and 50 controls underwent 3-tesla pulsed arterial spin-labeled MRI. SPM8 was used to test the effect of MC status at the voxel level on CBF before and after controlling for age and CDR. RESULTS MCs had decreased perfusion in the caudate and inferior striatum bilaterally even after controlling for age and CDR. In MCs, separate areas of decreased CBF were associated with increasing cerebral amyloid and to decreased performance of attention and executive function. CONCLUSIONS Early CBF changes were identified in asymptomatic and mildly symptomatic subjects with ADAD, particularly in the anterior striatum. Furthermore, amyloid deposition was associated with decreased CBF in a number of regions including anterior and posterior cortical areas. Both amyloid and decreased CBF were associated with declines primarily in executive cognitive function.
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Affiliation(s)
- Eric McDade
- From the Departments of Neurology (E.M., S.I., O.L., B.S.), Psychiatry (A.K., J.B., W.K.), and Radiology (J.J., D.M., J.P., C.M., W.K.), School of Medicine, and Department of Psychology (L.K.S., D.C.-H.K., P.J.G.), School of Arts and Sciences, University of Pittsburgh, PA; and Medical College of Georgia (A.K.), Augusta.
| | - Albert Kim
- From the Departments of Neurology (E.M., S.I., O.L., B.S.), Psychiatry (A.K., J.B., W.K.), and Radiology (J.J., D.M., J.P., C.M., W.K.), School of Medicine, and Department of Psychology (L.K.S., D.C.-H.K., P.J.G.), School of Arts and Sciences, University of Pittsburgh, PA; and Medical College of Georgia (A.K.), Augusta
| | - Jeffrey James
- From the Departments of Neurology (E.M., S.I., O.L., B.S.), Psychiatry (A.K., J.B., W.K.), and Radiology (J.J., D.M., J.P., C.M., W.K.), School of Medicine, and Department of Psychology (L.K.S., D.C.-H.K., P.J.G.), School of Arts and Sciences, University of Pittsburgh, PA; and Medical College of Georgia (A.K.), Augusta
| | - Lei K Sheu
- From the Departments of Neurology (E.M., S.I., O.L., B.S.), Psychiatry (A.K., J.B., W.K.), and Radiology (J.J., D.M., J.P., C.M., W.K.), School of Medicine, and Department of Psychology (L.K.S., D.C.-H.K., P.J.G.), School of Arts and Sciences, University of Pittsburgh, PA; and Medical College of Georgia (A.K.), Augusta
| | - Dora Chieh-Hsin Kuan
- From the Departments of Neurology (E.M., S.I., O.L., B.S.), Psychiatry (A.K., J.B., W.K.), and Radiology (J.J., D.M., J.P., C.M., W.K.), School of Medicine, and Department of Psychology (L.K.S., D.C.-H.K., P.J.G.), School of Arts and Sciences, University of Pittsburgh, PA; and Medical College of Georgia (A.K.), Augusta
| | - Davneet Minhas
- From the Departments of Neurology (E.M., S.I., O.L., B.S.), Psychiatry (A.K., J.B., W.K.), and Radiology (J.J., D.M., J.P., C.M., W.K.), School of Medicine, and Department of Psychology (L.K.S., D.C.-H.K., P.J.G.), School of Arts and Sciences, University of Pittsburgh, PA; and Medical College of Georgia (A.K.), Augusta
| | - Peter J Gianaros
- From the Departments of Neurology (E.M., S.I., O.L., B.S.), Psychiatry (A.K., J.B., W.K.), and Radiology (J.J., D.M., J.P., C.M., W.K.), School of Medicine, and Department of Psychology (L.K.S., D.C.-H.K., P.J.G.), School of Arts and Sciences, University of Pittsburgh, PA; and Medical College of Georgia (A.K.), Augusta
| | - Snezana Ikonomovic
- From the Departments of Neurology (E.M., S.I., O.L., B.S.), Psychiatry (A.K., J.B., W.K.), and Radiology (J.J., D.M., J.P., C.M., W.K.), School of Medicine, and Department of Psychology (L.K.S., D.C.-H.K., P.J.G.), School of Arts and Sciences, University of Pittsburgh, PA; and Medical College of Georgia (A.K.), Augusta
| | - Oscar Lopez
- From the Departments of Neurology (E.M., S.I., O.L., B.S.), Psychiatry (A.K., J.B., W.K.), and Radiology (J.J., D.M., J.P., C.M., W.K.), School of Medicine, and Department of Psychology (L.K.S., D.C.-H.K., P.J.G.), School of Arts and Sciences, University of Pittsburgh, PA; and Medical College of Georgia (A.K.), Augusta
| | - Beth Snitz
- From the Departments of Neurology (E.M., S.I., O.L., B.S.), Psychiatry (A.K., J.B., W.K.), and Radiology (J.J., D.M., J.P., C.M., W.K.), School of Medicine, and Department of Psychology (L.K.S., D.C.-H.K., P.J.G.), School of Arts and Sciences, University of Pittsburgh, PA; and Medical College of Georgia (A.K.), Augusta
| | - Julie Price
- From the Departments of Neurology (E.M., S.I., O.L., B.S.), Psychiatry (A.K., J.B., W.K.), and Radiology (J.J., D.M., J.P., C.M., W.K.), School of Medicine, and Department of Psychology (L.K.S., D.C.-H.K., P.J.G.), School of Arts and Sciences, University of Pittsburgh, PA; and Medical College of Georgia (A.K.), Augusta
| | - Jim Becker
- From the Departments of Neurology (E.M., S.I., O.L., B.S.), Psychiatry (A.K., J.B., W.K.), and Radiology (J.J., D.M., J.P., C.M., W.K.), School of Medicine, and Department of Psychology (L.K.S., D.C.-H.K., P.J.G.), School of Arts and Sciences, University of Pittsburgh, PA; and Medical College of Georgia (A.K.), Augusta
| | - Chet Mathis
- From the Departments of Neurology (E.M., S.I., O.L., B.S.), Psychiatry (A.K., J.B., W.K.), and Radiology (J.J., D.M., J.P., C.M., W.K.), School of Medicine, and Department of Psychology (L.K.S., D.C.-H.K., P.J.G.), School of Arts and Sciences, University of Pittsburgh, PA; and Medical College of Georgia (A.K.), Augusta
| | - William Klunk
- From the Departments of Neurology (E.M., S.I., O.L., B.S.), Psychiatry (A.K., J.B., W.K.), and Radiology (J.J., D.M., J.P., C.M., W.K.), School of Medicine, and Department of Psychology (L.K.S., D.C.-H.K., P.J.G.), School of Arts and Sciences, University of Pittsburgh, PA; and Medical College of Georgia (A.K.), Augusta
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16
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Klohs J, Rudin M, Shimshek DR, Beckmann N. Imaging of cerebrovascular pathology in animal models of Alzheimer's disease. Front Aging Neurosci 2014; 6:32. [PMID: 24659966 PMCID: PMC3952109 DOI: 10.3389/fnagi.2014.00032] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 02/19/2014] [Indexed: 01/04/2023] Open
Abstract
In Alzheimer's disease (AD), vascular pathology may interact with neurodegeneration and thus aggravate cognitive decline. As the relationship between these two processes is poorly understood, research has been increasingly focused on understanding the link between cerebrovascular alterations and AD. This has at last been spurred by the engineering of transgenic animals, which display pathological features of AD and develop cerebral amyloid angiopathy to various degrees. Transgenic models are versatile for investigating the role of amyloid deposition and vascular dysfunction, and for evaluating novel therapeutic concepts. In addition, research has benefited from the development of novel imaging techniques, which are capable of characterizing vascular pathology in vivo. They provide vascular structural read-outs and have the ability to assess the functional consequences of vascular dysfunction as well as to visualize and monitor the molecular processes underlying these pathological alterations. This article focusses on recent in vivo small animal imaging studies addressing vascular aspects related to AD. With the technical advances of imaging modalities such as magnetic resonance, nuclear and microscopic imaging, molecular, functional and structural information related to vascular pathology can now be visualized in vivo in small rodents. Imaging vascular and parenchymal amyloid-β (Aβ) deposition as well as Aβ transport pathways have been shown to be useful to characterize their dynamics and to elucidate their role in the development of cerebral amyloid angiopathy and AD. Structural and functional imaging read-outs have been employed to describe the deleterious affects of Aβ on vessel morphology, hemodynamics and vascular integrity. More recent imaging studies have also addressed how inflammatory processes partake in the pathogenesis of the disease. Moreover, imaging can be pivotal in the search for novel therapies targeting the vasculature.
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Affiliation(s)
- Jan Klohs
- Institute for Biomedical Engineering, University of Zurich and ETH Zurich Zurich, Switzerland ; Neuroscience Center Zurich, University of Zurich and ETH Zurich Zurich, Switzerland
| | - Markus Rudin
- Institute for Biomedical Engineering, University of Zurich and ETH Zurich Zurich, Switzerland ; Neuroscience Center Zurich, University of Zurich and ETH Zurich Zurich, Switzerland ; Institute of Pharmacology and Toxicology, University of Zurich Zurich, Switzerland
| | - Derya R Shimshek
- Autoimmunity, Transplantation and Inflammation/Neuroinflammation Department, Novartis Institutes for BioMedical Research Basel, Switzerland
| | - Nicolau Beckmann
- Analytical Sciences and Imaging, Novartis Institutes for BioMedical Research Basel, Switzerland
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17
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Thomason LAM, Stefanovic B, McLaurin J. Cerebrovascular contributions to Alzheimer's disease pathophysiology and potential therapeutic interventions in mouse models. Eur J Neurosci 2013; 37:1994-2004. [PMID: 23773069 DOI: 10.1111/ejn.12181] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 02/08/2013] [Accepted: 02/11/2013] [Indexed: 10/26/2022]
Abstract
The inter-relationship between vascular dysfunction and Alzheimer's disease pathology is not clearly understood; however, it is clear that the accumulation of amyloid-beta peptide and loss of vascular function contribute to the cognitive decline detected in patients. At present, imaging modalities can monitor the downstream effects of vascular dysfunction such as cerebral blood flow alterations, white and gray matter lacunes, and ischemic lesions; however, they cannot distinguish parenchymal plaques from cerebrovascular amyloid. Much of our understanding regarding the relationship between amyloid and vascular dysfunction has come from longitudinal population studies and mouse models. In this review, we will discuss the breadth of data generated on vascular function in mouse models of Alzheimer's disease and cerebrovascular amyloid angiopathy. We will also discuss therapeutic strategies targeting the reduction of cerebrovascular amyloid angiopathy and improvement of vascular function.
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Affiliation(s)
- Lynsie A M Thomason
- Department of Laboratory Medicine and Pathobiology, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
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18
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Krainik A, Villien M, Troprès I, Attyé A, Lamalle L, Bouvier J, Pietras J, Grand S, Le Bas JF, Warnking J. Functional imaging of cerebral perfusion. Diagn Interv Imaging 2013; 94:1259-78. [PMID: 24011870 DOI: 10.1016/j.diii.2013.08.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The functional imaging of perfusion enables the study of its properties such as the vasoreactivity to circulating gases, the autoregulation and the neurovascular coupling. Downstream from arterial stenosis, this imaging can estimate the vascular reserve and the risk of ischemia in order to adapt the therapeutic strategy. This method reveals the hemodynamic disorders in patients suffering from Alzheimer's disease or with arteriovenous malformations revealed by epilepsy. Functional MRI of the vasoreactivity also helps to better interpret the functional MRI activation in practice and in clinical research.
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Affiliation(s)
- A Krainik
- Clinique universitaire de neuroradiologie et IRM, CHU de Grenoble, CS 10217, 38043 Grenoble cedex, France; Inserm U836, université Joseph-Fourier, site santé, chemin Fortuné-Ferrini, 38706 La Tronche cedex, France; UMS IRMaGe, unité IRM 3T recherche, CHU de Grenoble, CS 10217, 38043 Grenoble cedex 9, France.
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19
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Klohs J, Politano IW, Deistung A, Grandjean J, Drewek A, Dominietto M, Keist R, Schweser F, Reichenbach JR, Nitsch RM, Knuesel I, Rudin M. Longitudinal Assessment of Amyloid Pathology in Transgenic ArcAβ Mice Using Multi-Parametric Magnetic Resonance Imaging. PLoS One 2013; 8:e66097. [PMID: 23840405 PMCID: PMC3686820 DOI: 10.1371/journal.pone.0066097] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Accepted: 05/02/2013] [Indexed: 12/20/2022] Open
Abstract
Magnetic resonance imaging (MRI) can be used to monitor pathological changes in Alzheimer's disease (AD). The objective of this longitudinal study was to assess the effects of progressive amyloid-related pathology on multiple MRI parameters in transgenic arcAβ mice, a mouse model of cerebral amyloidosis. Diffusion-weighted imaging (DWI), T1-mapping and quantitative susceptibility mapping (QSM), a novel MRI based technique, were applied to monitor structural alterations and changes in tissue composition imposed by the pathology over time. Vascular function and integrity was studied by assessing blood-brain barrier integrity with dynamic contrast-enhanced MRI and cerebral microbleed (CMB) load with susceptibility weighted imaging and QSM. A linear mixed effects model was built for each MRI parameter to incorporate effects within and between groups (i.e. genotype) and to account for changes unrelated to the disease pathology. Linear mixed effects modelling revealed a strong association of all investigated MRI parameters with age. DWI and QSM in addition revealed differences between arcAβ and wt mice over time. CMBs became apparent in arcAβ mice with 9 month of age; and the CMB load reflected disease stage. This study demonstrates the benefits of linear mixed effects modelling of longitudinal imaging data. Moreover, the diagnostic utility of QSM and assessment of CMB load should be exploited further in studies of AD.
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Affiliation(s)
- Jan Klohs
- Institute for Biomedical Engineering, ETH and University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
- * E-mail:
| | - Igna Wojtyna Politano
- Institute for Biomedical Engineering, ETH and University of Zurich, Zurich, Switzerland
| | - Andreas Deistung
- Medical Physics Group, Institute of Diagnostic and Interventional Radiology I, Jena University Hospital – Friedrich Schiller University Jena, Jena, Germany
| | - Joanes Grandjean
- Institute for Biomedical Engineering, ETH and University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Anna Drewek
- Seminar für Statistik, ETH Zurich, Zurich, Switzerland
| | - Marco Dominietto
- Institute for Biomedical Engineering, ETH and University of Zurich, Zurich, Switzerland
| | - Ruth Keist
- Institute for Biomedical Engineering, ETH and University of Zurich, Zurich, Switzerland
| | - Ferdinand Schweser
- Medical Physics Group, Institute of Diagnostic and Interventional Radiology I, Jena University Hospital – Friedrich Schiller University Jena, Jena, Germany
| | - Jürgen R. Reichenbach
- Medical Physics Group, Institute of Diagnostic and Interventional Radiology I, Jena University Hospital – Friedrich Schiller University Jena, Jena, Germany
| | - Roger M. Nitsch
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
- Division of Psychiatry Research, University of Zurich, Zurich, Switzerland
| | - Irene Knuesel
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Markus Rudin
- Institute for Biomedical Engineering, ETH and University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
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20
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Perles-Barbacaru TA, Procissi D, Demyanenko AV, Jacobs RE. Quantitative pharmacologic MRI in mice. NMR IN BIOMEDICINE 2012; 25:498-505. [PMID: 21793079 PMCID: PMC3292675 DOI: 10.1002/nbm.1760] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 05/03/2011] [Accepted: 05/19/2011] [Indexed: 05/31/2023]
Abstract
Pharmacologic MRI (phMRI) uses functional MRI techniques to provide a noninvasive in vivo measurement of the hemodynamic effects of drugs. The cerebral blood volume change (ΔCBV) serves as a surrogate for neuronal activity via neurovascular coupling mechanisms. By assessing the location and time course of brain activity in mouse mutant studies, phMRI can provide valuable insights into how different behavioral phenotypes are expressed in deferring brain activity response to drug challenge. In this report, we evaluate the utility of three different intravascular ultrasmall superparamagnetic iron oxide (USPIO) contrast agents for phMRI using a gradient-echo technique, with temporal resolution of one min at high magnetic field. The tissue half-life of the USPIOs was studied using a nonlinear detrending model. The three USPIOs are candidates for CBV weighted phMRI experiments, with r(2)/r(1) ratios ≥ 20 and apparent half-lives ≥ 1.5 h at the described doses. An echo-time of about 10 ms or longer results in a functional contrast to noise ratio (fCNR) > 75 after USPIO injection, with negligible decrease between 1.5-2 h. phMRI experiments were conducted at 7 T using cocaine as a psychotropic substance and acetazolamide, a global vasodilator, as a positive control. Cocaine acts as a dopamine-serotonin-norepinephrine reuptake inhibitor, increasing extracellular concentrations of these neurotransmitters, and thus increasing dopaminergic, serotonergic and noradrenergic neurotransmission. phMRI results showed that CBV was reduced in the normal mouse brain after cocaine challenge, with the largest effects in the nucleus accumbens, whereas after acetazolamide, blood volume was increased in both cerebral and extracerebral tissue.
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Affiliation(s)
| | - Daniel Procissi
- Biological Imaging Center, Beckman Institute, California Institute of Technology, Pasadena, CA 91125
| | - Andrey V. Demyanenko
- Biological Imaging Center, Beckman Institute, California Institute of Technology, Pasadena, CA 91125
| | - Russell E. Jacobs
- Biological Imaging Center, Beckman Institute, California Institute of Technology, Pasadena, CA 91125
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Contrast-enhanced magnetic resonance microangiography reveals remodeling of the cerebral microvasculature in transgenic ArcAβ mice. J Neurosci 2012; 32:1705-13. [PMID: 22302811 DOI: 10.1523/jneurosci.5626-11.2012] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Amyloid-β (Aβ) deposition in the cerebral vasculature is accompanied by remodeling which has a profound influence on vascular integrity and function. In the current study we have quantitatively assessed the age-dependent changes of the cortical vasculature in the arcAβ model of cerebral amyloidosis. To estimate the density of the cortical microvasculature in vivo, we used contrast-enhanced magnetic resonance microangiography (CE-μMRA). Three-dimensional gradient echo datasets with 60 μm isotropic resolution were acquired in 4- and 24-month-old arcAβ mice and compared with wild-type (wt) control mice of the same age before and after administration of superparamagnetic iron oxide nanoparticles. After segmentation of the cortical vasculature from difference images, an automated algorithm was applied for assessing the number and size distribution of intracortical vessels. With CE-μMRA, cerebral arteries and veins with a diameter of less than the nominal pixel resolution (60 μm) can be visualized. A significant age-dependent reduction in the number of functional intracortical microvessels (radii of 20-80 μm) has been observed in 24-month-old arcAβ mice compared with age-matched wt mice, whereas there was no difference between transgenic and wt mice of 4 months of age. Immunohistochemistry demonstrated strong fibrinogen and Aβ deposition in small- and medium-sized vessels, but not in large cerebral arteries, of 24-month-old arcAβ mice. The reduced density of transcortical vessels may thus be attributed to impaired perfusion and vascular occlusion caused by deposition of Aβ and fibrin. The study demonstrated that remodeling of the cerebrovasculature can be monitored noninvasively with CE-μMRA in mice.
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Abstract
Neuroimaging allows researchers and clinicians to noninvasively assess structure and function of the brain. With the advances of imaging modalities such as magnetic resonance, nuclear, and optical imaging; the design of target-specific probes; and/or the introduction of reporter gene assays, these technologies are now capable of visualizing cellular and molecular processes in vivo. Undoubtedly, the system biological character of molecular neuroimaging, which allows for the study of molecular events in the intact organism, will enhance our understanding of physiology and pathophysiology of the brain and improve our ability to diagnose and treat diseases more specifically. Technical/scientific challenges to be faced are the development of highly sensitive imaging modalities, the design of specific imaging probe molecules capable of penetrating the CNS and reporting on endogenous cellular and molecular processes, and the development of tools for extracting quantitative, biologically relevant information from imaging data. Today, molecular neuroimaging is still an experimental approach with limited clinical impact; this is expected to change within the next decade. This article provides an overview of molecular neuroimaging approaches with a focus on rodent studies documenting the exploratory state of the field. Concepts are illustrated by discussing applications related to the pathophysiology of Alzheimer's disease.
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Affiliation(s)
- Jan Klohs
- Institute for Biomedical Engineering, ETH & University of Zürich, Switzerland
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Genetic animal models of cerebral vasculopathies. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 105:25-55. [PMID: 22137428 DOI: 10.1016/b978-0-12-394596-9.00002-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cerebral amyloid angiopathy (CAA) and cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) are genetic cerebrovasculopathies associated with neurodegeneration and vascular cognitive impairment. Linked to autosomal dominant mutations in diverse genes that encode cell-surface receptors (i.e., amyloid precursor protein in CAA and NOTCH3 in CADASIL), both diseases are associated with accumulation of abnormal material around cerebral vessels, such as amyloid in CAA or granular osmiophilic material in CADASIL. Both CAA and CADASIL share clinical features of white matter degeneration and infarcts, and vascular dementia in the human adult; microbleeds occur in both CADASIL and CAA, but large intracerebral hemorrhages are more characteristic for the latter. While the mechanisms are poorly understood, wall thickening, luminal narrowing, and eventual loss of vascular smooth muscle cells are overlapping pathologies involving leptomeningeal, and pial or penetrating small arteries and arterioles in CAA and CADASIL. Dysregulation of cerebral blood flow and eventual hypoperfusion are believed to be the key pathophysiological steps in neurodegeneration and cognitive impairment. Although animal models expressing CAA or CADASIL mutations have partially reproduced the human pathology, there has been marked heterogeneity in the phenotypic spectrum, possibly due to genetic background differences among mouse models, and obvious species differences between mouse and man. Here, we provide an overview of animal models of CAA and CADASIL and the insight on molecular and physiological mechanisms of disease gained from these models.
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Kokjohn TA, Van Vickle GD, Maarouf CL, Kalback WM, Hunter JM, Daugs ID, Luehrs DC, Lopez J, Brune D, Sue LI, Beach TG, Castaño EM, Roher AE. Chemical characterization of pro-inflammatory amyloid-beta peptides in human atherosclerotic lesions and platelets. Biochim Biophys Acta Mol Basis Dis 2011; 1812:1508-14. [PMID: 21784149 DOI: 10.1016/j.bbadis.2011.07.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 06/27/2011] [Accepted: 07/05/2011] [Indexed: 01/23/2023]
Abstract
Amyloid-β (Aβ) peptides are intimately involved in the inflammatory pathology of atherosclerotic vascular disease (AVD) and Alzheimer's disease (AD). Although substantial amounts of these peptides are produced in the periphery, their role and significance to vascular disease outside the brain requires further investigation. Amyloid-β peptides present in the walls of human aorta atherosclerotic lesions as well as activated and non-activated human platelets were isolated using sequential size-exclusion columns and HPLC reverse-phase methods. The Aβ peptide isolates were quantified by ELISA and structurally analyzed using MALDI-TOF mass spectrometry procedures. Our experiments revealed that both aorta and platelets contained Aβ peptides, predominately Aβ40. The source of the Aβ pool in aortic atherosclerosis lesions is probably the activated platelets and/or vascular wall cells expressing APP/PN2. Significant levels of Aβ42 are present in the plasma, suggesting that this reservoir makes a minor contribution to atherosclerotic plaques. Our data reveal that although aortic atherosclerosis and AD cerebrovascular amyloidosis exhibit clearly divergent end-stage manifestations, both vascular diseases share some key pathophysiological promoting elements and pathways. Whether they happen to be deposited in vessels of the central nervous system or atherosclerotic plaques in the periphery, Aβ peptides may promote and perhaps synergize chronic inflammatory processes which culminate in the degeneration, malfunction and ultimate destruction of arterial walls.
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Affiliation(s)
- Tyler A Kokjohn
- The Longtine Center for Neurodegenerative Biochemistry, Banner Sun Health Research Institute, Sun City, AZ 85351, USA
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Impaired cerebral vasoreactivity to CO2 in Alzheimer's disease using BOLD fMRI. Neuroimage 2011; 58:579-87. [PMID: 21745581 DOI: 10.1016/j.neuroimage.2011.06.070] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 05/13/2011] [Accepted: 06/23/2011] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVE To evaluate the cerebral vasoreactivity using blood oxygenation level dependent functional MRI during carbogen inhalation with 7% CO(2) in Alzheimer's disease and amnestic mild cognitive impairment. PARTICIPANTS AND METHODS Thirty nine subjects were included to be investigated using blood oxygenation level dependent (BOLD) functional MRI at 1.5T during a block-design carbogen inhalation paradigm, with a high concentration face-mask under physiological monitoring. Basal cerebral perfusion was measured using pulsed arterial spin labeling. Image analyses were conducted using Matlab® and SPM5 with physiological regressors and corrected for partial volume effect. RESULTS Among selected participants, 12 subjects were excluded because of incomplete protocol, leaving for analysis 27 subjects without significant microangiopathy diagnosed for Alzheimer's disease (n=9), amnestic mild cognitive impairment (n=7), and matched controls (n=11). No adverse reaction related to the CO(2) challenge was reported. Carbogen inhalation induced a whole-brain signal increase, predominant in the gray matter. In patients, signal changes corrected for gray matter partial volume were decreased (0.36±0.13% BOLD/mmHg in Alzheimer's disease, 0.36±0.12 in patients with mild cognitive impairment, 0.62±0.20 in controls). Cerebral vasoreactivity impairments were diffuse but seemed predominant in posterior areas. The basal hypoperfusion in Alzheimer's disease was not significantly different from patients with mild cognitive impairment and controls. Among clinical and biological parameters, no effect of apoE4 genotype was detected. Cerebral vasoreactivity values were correlated with cognitive performances and hippocampal volumes. Among age and hippocampal atrophy, mean CVR was the best predictor of the mini-mental status examination. CONCLUSION This BOLD functional MRI study on CO(2) challenge shows impaired cerebral vasoreactivity in patients with Alzheimer's disease and amnestic mild cognitive impairment at the individual level. These preliminary findings using a new MRI approach may help to better characterize patients with cognitive disorders in clinical practice and further investigate vaso-protective therapeutics.
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Rotman M, Snoeks TJA, van der Weerd L. Pre-clinical optical imaging and MRI for drug development in Alzheimer's disease. DRUG DISCOVERY TODAY. TECHNOLOGIES 2011; 8:e117-e125. [PMID: 24990260 DOI: 10.1016/j.ddtec.2011.11.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Optical and magnetic resonance imaging have the potential to be complementary non-invasive imaging modalities. Yet without advances in imaging technologies and contrast agents both have short-comings that cannot be ignored. In this review we demonstrate the pre-clinical use of the two imaging techniques in Alzheimer's disease, including examples from recent applications and discuss what is needed to improve their applicability for drug discovery.:
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Affiliation(s)
- Maarten Rotman
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
| | - Thomas J A Snoeks
- Department of Endocrinology, Leiden University Medical Center, Leiden, The Netherlands
| | - Louise van der Weerd
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
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