101
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Xu J, Su Y, Fu J, Shen Y, Dong Q, Cheng X. Glymphatic pathway in sporadic cerebral small vessel diseases: From bench to bedside. Ageing Res Rev 2023; 86:101885. [PMID: 36801378 DOI: 10.1016/j.arr.2023.101885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 02/09/2023] [Accepted: 02/14/2023] [Indexed: 02/18/2023]
Abstract
Cerebral small vessel diseases (CSVD) consist of a group of diseases with high heterogeneity induced by pathologies of intracranial small blood vessels. Endothelium dysfunction, bloodbrain barrier leakage and the inflammatory response are traditionally considered to participate in the pathogenesis of CSVD. However, these features cannot fully explain the complex syndrome and related neuroimaging characteristics. In recent years, the glymphatic pathway has been discovered to play a pivotal role in clearing perivascular fluid and metabolic solutes, which has provided novel insights into neurological disorders. Researchers have also explored the potential role of perivascular clearance dysfunction in CSVD. In this review, we presented a brief overview of CSVD and the glymphatic pathway. In addition, we elucidated CSVD pathogenesis from the perspective of glymphatic failure, including basic animal models and clinical neuroimaging markers. Finally, we proposed forthcoming clinical applications targeting the glymphatic pathway, hoping to provide novel ideas on promising therapies and preventions of CSVD.
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Affiliation(s)
- Jiajie Xu
- Department of Neurology, National Center for Neurological Disorders, National Clinical Research Centre for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Ya Su
- Department of Neurology, National Center for Neurological Disorders, National Clinical Research Centre for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Jiayu Fu
- Department of Neurology, National Center for Neurological Disorders, National Clinical Research Centre for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Yong Shen
- Institute on Aging and Brain Disorders, The First Affiliated Hospital of USTC and Neurodegenerative Disorder Research Center, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Qiang Dong
- Department of Neurology, National Center for Neurological Disorders, National Clinical Research Centre for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Xin Cheng
- Department of Neurology, National Center for Neurological Disorders, National Clinical Research Centre for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China.
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102
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Zhang Y, Zhang C, He XZ, Li ZH, Meng JC, Mao RT, Li X, Xue R, Gui Q, Zhang GX, Wang LH. Interaction Between the Glymphatic System and α-Synuclein in Parkinson's Disease. Mol Neurobiol 2023; 60:2209-2222. [PMID: 36637746 DOI: 10.1007/s12035-023-03212-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 01/04/2023] [Indexed: 01/14/2023]
Abstract
The glymphatic system contributes to the clearance of amyloid-β from the brain and is disrupted in Alzheimer's disease. However, whether the system is involved in the removal of α-synuclein (α-syn) and whether it is suppressed in Parkinson's disease (PD) remain largely unknown. In mice receiving the intranigral injection of recombinant human α-syn, we found that the glymphatic suppression via aquaporin-4 (AQP4) gene deletion or acetazolamide treatment reduced the clearance of injected α-syn from the brain. In mice overexpressing the human A53T-α-syn, we revealed that AQP4 deficiency accelerated the accumulation of α-syn, facilitated the loss of dopaminergic neurons, and accelerated PD-like symptoms. We also found that the overexpression of A53T-α-syn reduced the expression/polarization of AQP4 and suppressed the glymphatic activity of mice. The study demonstrates a close interaction between the AQP4-mediated glymphatic system and parenchymal α-syn, indicating that restoring the glymphatic activity is a potential therapeutic target to delay PD progression.
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Affiliation(s)
- Yu Zhang
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, 199 Ren-Ai Road, Suzhou, 215123, People's Republic of China
| | - Cui Zhang
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, 199 Ren-Ai Road, Suzhou, 215123, People's Republic of China
| | - Xu-Zhong He
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, 199 Ren-Ai Road, Suzhou, 215123, People's Republic of China
| | - Zhen-Hua Li
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, 199 Ren-Ai Road, Suzhou, 215123, People's Republic of China
| | - Jing-Cai Meng
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, 199 Ren-Ai Road, Suzhou, 215123, People's Republic of China
| | - Rui-Ting Mao
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, 199 Ren-Ai Road, Suzhou, 215123, People's Republic of China
| | - Xin Li
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, 199 Ren-Ai Road, Suzhou, 215123, People's Republic of China
| | - Rong Xue
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, 199 Ren-Ai Road, Suzhou, 215123, People's Republic of China
| | - Qian Gui
- Department of Neurology, Suzhou Municipal Hospital, 26 Dao-Qian Street, Suzhou, 215002, People's Republic of China
| | - Guo-Xing Zhang
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, 199 Ren-Ai Road, Suzhou, 215123, People's Republic of China
| | - Lin-Hui Wang
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, 199 Ren-Ai Road, Suzhou, 215123, People's Republic of China.
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103
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Yamada K. Multifaceted Roles of Aquaporins in the Pathogenesis of Alzheimer’s Disease. Int J Mol Sci 2023; 24:ijms24076528. [PMID: 37047501 PMCID: PMC10095057 DOI: 10.3390/ijms24076528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 03/29/2023] [Accepted: 03/29/2023] [Indexed: 04/03/2023] Open
Abstract
The central nervous system is highly dependent on water, and disturbances in water homeostasis can have a significant impact on its normal functions. The regulation of water balance is, at least in part, carried out via specialized water channels called aquaporins. In the central nervous system, two major aquaporins (AQPs), AQP1 and AQP4, and their potential involvements have been long implicated in the pathophysiology of many brain disorders such as brain edema and Neuromyelitis optica. In addition to these diseases, there is growing attention to the involvement of AQPs in the removal of waste products in Alzheimer’s disease (AD). This indicates that targeting fluid homeostasis is a novel and attractive approach for AD. This review article aims to summarize recent knowledge on the pathological implications of AQPs in AD, discussing unsolved questions and future prospects.
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Affiliation(s)
- Kaoru Yamada
- Department of Neuropathology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
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104
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Sepehrinezhad A, Stolze Larsen F, Ashayeri Ahmadabad R, Shahbazi A, Sahab Negah S. The Glymphatic System May Play a Vital Role in the Pathogenesis of Hepatic Encephalopathy: A Narrative Review. Cells 2023; 12:cells12070979. [PMID: 37048052 PMCID: PMC10093707 DOI: 10.3390/cells12070979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 02/20/2023] [Accepted: 03/21/2023] [Indexed: 04/14/2023] Open
Abstract
Hepatic encephalopathy (HE) is a neurological complication of liver disease resulting in cognitive, psychiatric, and motor symptoms. Although hyperammonemia is a key factor in the pathogenesis of HE, several other factors have recently been discovered. Among these, the impairment of a highly organized perivascular network known as the glymphatic pathway seems to be involved in the progression of some neurological complications due to the accumulation of misfolded proteins and waste substances in the brain interstitial fluids (ISF). The glymphatic system plays an important role in the clearance of brain metabolic derivatives and prevents aggregation of neurotoxic agents in the brain ISF. Impairment of it will result in aggravated accumulation of neurotoxic agents in the brain ISF. This could also be the case in patients with liver failure complicated by HE. Indeed, accumulation of some metabolic by-products and agents such as ammonia, glutamine, glutamate, and aromatic amino acids has been reported in the human brain ISF using microdialysis technique is attributed to worsening of HE and correlates with brain edema. Furthermore, it has been reported that the glymphatic system is impaired in the olfactory bulb, prefrontal cortex, and hippocampus in an experimental model of HE. In this review, we discuss different factors that may affect the function of the glymphatic pathways and how these changes may be involved in HE.
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Affiliation(s)
- Ali Sepehrinezhad
- Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran 1449614535, Iran
- Neuroscience Research Center, Mashhad University of Medical Sciences, Mashhad 9919191778, Iran
| | - Fin Stolze Larsen
- Department of Gastroenterology and Hepatology, Rigshospitalet, Copenhagen University Hospital, 999017 Copenhagen, Denmark
| | | | - Ali Shahbazi
- Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran 1449614535, Iran
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran 1449614535, Iran
| | - Sajad Sahab Negah
- Neuroscience Research Center, Mashhad University of Medical Sciences, Mashhad 9919191778, Iran
- Shefa Neuroscience Research Center, Khatam Alanbia Hospital, Tehran 1449614535, Iran
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105
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Kecheliev V, Boss L, Maheshwari U, Konietzko U, Keller A, Razansky D, Nitsch RM, Klohs J, Ni R. Aquaporin 4 is differentially increased and dislocated in association with tau and amyloid-beta. Life Sci 2023; 321:121593. [PMID: 36934970 DOI: 10.1016/j.lfs.2023.121593] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 03/08/2023] [Accepted: 03/14/2023] [Indexed: 03/19/2023]
Abstract
AIMS Neurovascular-glymphatic dysfunction plays an important role in Alzheimer's disease and has been analysed mainly in relation to amyloid-beta (Aβ) pathology. Here, we aim to investigate the neurovascular alterations and mapping of aquaporin 4 (AQP4) distribution and dislocation associated with tau and Aβ. MATERIALS AND METHODS Perfusion, susceptibility weighted imaging and structural magnetic resonance imaging (MRI) were performed in the pR5 mouse model of 4-repeat tau and the arcAβ mouse model of amyloidosis. Immunofluorescence staining was performed using antibodies against AQP4, vessel, astroglia, microglia, phospho-tau and Aβ in brain tissue slices from pR5, arcAβ and non-transgenic mice. KEY FINDINGS pR5 mice showed regional atrophy, preserved cerebral blood flow, and reduced cerebral vessel density compared to non-transgenic mice, while arcAβ mice showed cerebral microbleeds and reduced cerebral vessel density. AQP4 dislocation and peri-tau enrichment in the hippocampus and increased AQP4 levels in the cortex and hippocampus were detected in pR5 mice compared to non-transgenic mice. In comparison, cortical AQP4 dislocation and cortical/hippocampal peri-plaque increases were observed in arcAβ mice. Increased expression of reactive astrocytes were detected around the tau inclusions in pR5 mice and Aβ plaques in arcAβ mice. SIGNIFICANCE We demonstrated the neurovascular alterations, microgliosis, astrogliosis and increased AQP4 regional expression in pR5 tau and arcAβ mice. We observed a divergent region-specific AQP4 dislocation and association with phospho-tau and Aβ pathologies.
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Affiliation(s)
- Vasil Kecheliev
- Institute for Regenerative Medicine, University of Zurich, Zurich, Switzerland
| | - Leo Boss
- Institute for Regenerative Medicine, University of Zurich, Zurich, Switzerland
| | - Upasana Maheshwari
- Department of Neurosurgery, Clinical Neuroscience Center, Zürich University Hospital, Zurich, Switzerland
| | - Uwe Konietzko
- Institute for Regenerative Medicine, University of Zurich, Zurich, Switzerland
| | - Annika Keller
- Department of Neurosurgery, Clinical Neuroscience Center, Zürich University Hospital, Zurich, Switzerland; Zentrum für Neurowissenschaften Zurich, Zurich, Switzerland
| | - Daniel Razansky
- Zentrum für Neurowissenschaften Zurich, Zurich, Switzerland; Institute for Biomedical Engineering, ETH Zurich & University of Zurich, Zurich, Switzerland
| | - Roger M Nitsch
- Institute for Regenerative Medicine, University of Zurich, Zurich, Switzerland; Zentrum für Neurowissenschaften Zurich, Zurich, Switzerland
| | - Jan Klohs
- Institute for Biomedical Engineering, ETH Zurich & University of Zurich, Zurich, Switzerland
| | - Ruiqing Ni
- Institute for Regenerative Medicine, University of Zurich, Zurich, Switzerland; Zentrum für Neurowissenschaften Zurich, Zurich, Switzerland; Institute for Biomedical Engineering, ETH Zurich & University of Zurich, Zurich, Switzerland.
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106
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Alghanimy A, Martin C, Gallagher L, Holmes WM. The effect of a novel AQP4 facilitator, TGN-073, on glymphatic transport captured by diffusion MRI and DCE-MRI. PLoS One 2023; 18:e0282955. [PMID: 36920936 PMCID: PMC10016657 DOI: 10.1371/journal.pone.0282955] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 02/27/2023] [Indexed: 03/16/2023] Open
Abstract
The glymphatic system is a low resistance pathway, by which cerebrospinal fluid enters the brain parenchyma along perivascular spaces via AQP4 channels. It is hypothesised that the resulting convective flow of the interstitial fluid provides an efficient mechanism for the removal of waste toxins from the brain. Therefore, enhancing AQP4 function might protect against neurodegenerative diseases such as Alzheimer's disease (AD), in which the accumulation of harmful proteins and solutes is a hallmark feature. Here, we test the effect of a putative AQP4 facilitator, TGN-073, on glymphatic transport in a normal rat brain by employing different MRI techniques. Surgical procedures were undertaken to catheterise the cisterna magna, thereby enabling infusion of the MRI tracer. Followed by the intraperitoneal injection of either TGN-073, or the vehicle. Using a paramagnetic contrast agent (Gd-DTPA) as the MRI tracer, dynamic 3D T1 weighted imaging of the glymphatic system was undertaken over two hours. Further, the apparent diffusion coefficient was measured in different brain regions using diffusion-weighted imaging (DWI). While physiological parameters and arterial blood gas analysis were monitored continuously. We found that rats treated with TGN-073 showed the distribution of Gd-DTPA was more extensive and parenchymal uptake was higher compared with the vehicle group. Water diffusivity was increased in the brain of TGN-073 treated group, which indicates greater water flux. Also, MRI showed the glymphatic transport and distribution in the brain is naturally heterogeneous, which is consistent with previous studies. Our results indicate that compounds such as TGN-073 can improve glymphatic function in the brain. Since glymphatic impairment due to AQP4 dysfunction is potentially associated with several neurological disorders such as AD, dementia and traumatic brain injury, enhancing AQP4 functionality might be a promising therapeutic target.
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Affiliation(s)
- Alaa Alghanimy
- Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Science, University of Glasgow, Glasgow, United Kingdom
- Radiological Sciences Department, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Conor Martin
- Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Science, University of Glasgow, Glasgow, United Kingdom
| | - Lindsay Gallagher
- Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Science, University of Glasgow, Glasgow, United Kingdom
| | - William M. Holmes
- Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Science, University of Glasgow, Glasgow, United Kingdom
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107
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Jia Y, Xu S, Han G, Wang B, Wang Z, Lan C, Zhao P, Gao M, Zhang Y, Jiang W, Qiu B, Liu R, Hsu YC, Sun Y, Liu C, Liu Y, Bai R. Transmembrane water-efflux rate measured by magnetic resonance imaging as a biomarker of the expression of aquaporin-4 in gliomas. Nat Biomed Eng 2023; 7:236-252. [PMID: 36376487 DOI: 10.1038/s41551-022-00960-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 10/10/2022] [Indexed: 11/16/2022]
Abstract
The water-selective channel protein aquaporin-4 (AQP4) contributes to the migration and proliferation of gliomas, and to their resistance to therapy. Here we show, in glioma cell cultures, in subcutaneous and orthotopic gliomas in rats, and in glioma tumours in patients, that transmembrane water-efflux rate is a sensitive biomarker of AQP4 expression and can be measured via conventional dynamic-contrast-enhanced magnetic resonance imaging. Water-efflux rates correlated with stages of glioma proliferation as well as with changes in the heterogeneity of intra-tumoural and inter-tumoural AQP4 in rodent and human gliomas following treatment with temozolomide and with the AQP4 inhibitor TGN020. Regions with low water-efflux rates contained higher fractions of stem-like slow-cycling cells and therapy-resistant cells, suggesting that maps of water-efflux rates could be used to identify gliomas that are resistant to therapies.
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Affiliation(s)
- Yinhang Jia
- Department of Physical Medicine and Rehabilitation of the Affiliated Sir Run Run Shaw Hospital AND Interdisciplinary Institute of Neuroscience and Technology, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China
- Department of Neurosurgery, Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Shangchen Xu
- Department of Neurosurgery, Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Guangxu Han
- Key Laboratory of Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China
| | - Bao Wang
- Department of Radiology, Qilu Hospital of Shandong University, Jinan, China
| | - Zejun Wang
- Key Laboratory of Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China
| | - Chuanjin Lan
- Department of Neurosurgery, Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Peng Zhao
- Department of Neurosurgery, Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Meng Gao
- Department of Neurosurgery, Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Yi Zhang
- Department of Radiology, Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Wenhong Jiang
- Zhejiang University School of Medicine, Hangzhou, China
| | - Biying Qiu
- Zhejiang University School of Medicine, Hangzhou, China
| | - Rui Liu
- Zhejiang University School of Medicine, Hangzhou, China
| | - Yi-Cheng Hsu
- MR Collaboration, Siemens Healthcare, Shanghai, China
| | - Yi Sun
- MR Collaboration, Siemens Healthcare, Shanghai, China
| | - Chong Liu
- MOE Frontier Science Center for Brain Science and Brain-machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
| | - Yingchao Liu
- Department of Neurosurgery, Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China.
- Shandong National Center for Applied Mathematics, Shandong University, Jinan, China.
| | - Ruiliang Bai
- Department of Physical Medicine and Rehabilitation of the Affiliated Sir Run Run Shaw Hospital AND Interdisciplinary Institute of Neuroscience and Technology, Zhejiang University School of Medicine, Hangzhou, China.
- Key Laboratory of Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China.
- MOE Frontier Science Center for Brain Science and Brain-machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China.
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108
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Yao D, Zhang R, Xie M, Ding F, Wang M, Wang W. Updated Understanding of the Glial-Vascular Unit in Central Nervous System Disorders. Neurosci Bull 2023; 39:503-518. [PMID: 36374471 PMCID: PMC10043098 DOI: 10.1007/s12264-022-00977-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 09/04/2022] [Indexed: 11/16/2022] Open
Abstract
The concept of the glial-vascular unit (GVU) was raised recently to emphasize the close associations between brain cells and cerebral vessels, and their coordinated reactions to diverse neurological insults from a "glio-centric" view. GVU is a multicellular structure composed of glial cells, perivascular cells, and perivascular space. Each component is closely linked, collectively forming the GVU. The central roles of glial and perivascular cells and their multi-level interconnections in the GVU under normal conditions and in central nervous system (CNS) disorders have not been elucidated in detail. Here, we comprehensively review the intensive interactions between glial cells and perivascular cells in the niche of perivascular space, which take part in the modulation of cerebral blood flow and angiogenesis, formation of the blood-brain barrier, and clearance of neurotoxic wastes. Next, we discuss dysfunctions of the GVU in various neurological diseases, including ischemic stroke, spinal cord injury, Alzheimer's disease, and major depression disorder. In addition, we highlight the possible therapies targeting the GVU, which may have potential clinical applications.
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Affiliation(s)
- Di Yao
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Ruoying Zhang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Minjie Xie
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Fengfei Ding
- Department of Pharmacology, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China
| | - Minghuan Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Wei Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
- Key Laboratory of Neurological Diseases of the Chinese Ministry of Education, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
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109
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Salminen A. Activation of aryl hydrocarbon receptor (AhR) in Alzheimer's disease: role of tryptophan metabolites generated by gut host-microbiota. J Mol Med (Berl) 2023; 101:201-222. [PMID: 36757399 PMCID: PMC10036442 DOI: 10.1007/s00109-023-02289-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 12/19/2022] [Accepted: 01/17/2023] [Indexed: 02/10/2023]
Abstract
Gut microbiota in interaction with intestinal host tissues influences many brain functions and microbial dysbiosis has been linked with brain disorders, such as neuropsychiatric conditions and Alzheimer's disease (AD). L-tryptophan metabolites and short-chained fatty acids (SCFA) are major messengers in the microbiota-brain axis. Aryl hydrocarbon receptors (AhR) are main targets of tryptophan metabolites in brain microvessels which possess an enriched expression of AhR protein. The Ah receptor is an evolutionarily conserved, ligand-activated transcription factor which is not only a sensor of xenobiotic toxins but also a pleiotropic regulator of both developmental processes and age-related tissue degeneration. Major microbiota-produced tryptophan metabolites involve indole derivatives, e.g., indole 3-pyruvic acid, indole 3-acetaldehyde, and indoxyl sulfate, whereas indoleamine and tryptophan 2,3-dioxygenases (IDO/TDO) of intestine host cells activate the kynurenine (KYN) pathway generating KYN metabolites, many of which are activators of AhR signaling. Chronic kidney disease (CKD) increases the serum level of indoxyl sulfate which promotes AD pathogenesis, e.g., it disrupts integrity of blood-brain barrier (BBB) and impairs cognitive functions. Activation of AhR signaling disturbs vascular homeostasis in brain; (i) it controls blood flow via the renin-angiotensin system, (ii) it inactivates endothelial nitric oxide synthase (eNOS), thus impairing NO production and vasodilatation, and (iii) it induces oxidative stress, stimulates inflammation, promotes cellular senescence, and enhances calcification of vascular walls. All these alterations are evident in cerebral amyloid angiopathy (CAA) in AD pathology. Moreover, AhR signaling can disturb circadian regulation and probably affect glymphatic flow. It seems plausible that dysbiosis of gut microbiota impairs the integrity of BBB via the activation of AhR signaling and thus aggravates AD pathology. KEY MESSAGES: Dysbiosis of gut microbiota is associated with dementia and Alzheimer's disease. Tryptophan metabolites are major messengers from the gut host-microbiota to brain. Tryptophan metabolites activate aryl hydrocarbon receptor (AhR) signaling in brain. The expression of AhR protein is enriched in brain microvessels and blood-brain barrier. Tryptophan metabolites disturb brain vascular integrity via AhR signaling. Dysbiosis of gut microbiota promotes inflammation and AD pathology via AhR signaling.
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Affiliation(s)
- Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, Kuopio, 70211, Finland.
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110
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Preclinical Research on Focused Ultrasound-Mediated Blood-Brain Barrier Opening for Neurological Disorders: A Review. Neurol Int 2023; 15:285-300. [PMID: 36810473 PMCID: PMC9944161 DOI: 10.3390/neurolint15010018] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/02/2023] [Accepted: 02/10/2023] [Indexed: 02/17/2023] Open
Abstract
Several therapeutic agents for neurological disorders are usually not delivered to the brain owing to the presence of the blood-brain barrier (BBB), a special structure present in the central nervous system (CNS). Focused ultrasound (FUS) combined with microbubbles can reversibly and temporarily open the BBB, enabling the application of various therapeutic agents in patients with neurological disorders. In the past 20 years, many preclinical studies on drug delivery through FUS-mediated BBB opening have been conducted, and the use of this method in clinical applications has recently gained popularity. As the clinical application of FUS-mediated BBB opening expands, it is crucial to understand the molecular and cellular effects of FUS-induced microenvironmental changes in the brain so that the efficacy of treatment can be ensured, and new treatment strategies established. This review describes the latest research trends in FUS-mediated BBB opening, including the biological effects and applications in representative neurological disorders, and suggests future directions.
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111
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Deng Z, Wang H, Huang K, Li Y, Ran Y, Chen Y, Zhou L. Association between vascular risk factors and idiopathic normal pressure hydrocephalus: a Mendelian randomization study. J Neurol 2023; 270:2724-2733. [PMID: 36773060 DOI: 10.1007/s00415-023-11604-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/01/2023] [Accepted: 02/02/2023] [Indexed: 02/12/2023]
Abstract
BACKGROUND AND OBJECTIVE Patients with idiopathic normal pressure hydrocephalus (iNPH) have a higher prevalence of hypertension and diabetes. However, the causal effects of these vascular risk factors on iNPH remain unclear. This study aimed to explore the causal relationship between vascular risk factors (VRFs) and iNPH. METHODS We conducted the Mendelian randomization (MR) analysis of iNPH. We included nineteen vascular risk factors related to hypertension, diabetes, lipids, obesity, smoking, alcohol consumption, exercise, sleep, and cardiovascular events as exposure factors. We used the inverse-variance weighted method for causal effect estimation and weighted median, maximum likelihood, and MR Egger regression methods for sensitivity analyses. RESULTS We found that genetically predicting essential hypertension (OR = 1.608 (1.330-1.944), p = 0.013) and increased sleep duration (OR = 16.395 (5.624-47.799), p = 0.009) were associated with higher odds of iNPH. Type 1 diabetes (OR = 0.869 (0.828-0.913), p = 0.004) was associated with lower odds of iNPH. For the other 16 VRFs, there was no evidence that they were significantly associated with iNPH. Sensitivity analyses showed that essential hypertension and type 1 diabetes were significantly associated with iNPH. CONCLUSION In our MR study on VRFs and iNPH, we found essential hypertension to be a causal risk factor for iNPH. This suggests that hypertension may be involved in the pathophysiological mechanism of iNPH.
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Affiliation(s)
- Ziang Deng
- Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, China
| | - Haoxiang Wang
- Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, China
| | - Keru Huang
- Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, China
| | - Yuanyou Li
- Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, China
| | - Yang Ran
- Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, China
| | - Yaxing Chen
- Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, China
| | - Liangxue Zhou
- Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, China.
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112
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Gomolka RS, Hablitz LM, Mestre H, Giannetto M, Du T, Hauglund NL, Xie L, Peng W, Martinez PM, Nedergaard M, Mori Y. Loss of aquaporin-4 results in glymphatic system dysfunction via brain-wide interstitial fluid stagnation. eLife 2023; 12:82232. [PMID: 36757363 PMCID: PMC9995113 DOI: 10.7554/elife.82232] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 02/08/2023] [Indexed: 02/10/2023] Open
Abstract
The glymphatic system is a fluid transport network of cerebrospinal fluid (CSF) entering the brain along arterial perivascular spaces, exchanging with interstitial fluid (ISF), ultimately establishing directional clearance of interstitial solutes. CSF transport is facilitated by the expression of aquaporin-4 (AQP4) water channels on the perivascular endfeet of astrocytes. Mice with genetic deletion of AQP4 (AQP4 KO) exhibit abnormalities in the brain structure and molecular water transport. Yet, no studies have systematically examined how these abnormalities in structure and water transport correlate with glymphatic function. Here, we used high-resolution 3D magnetic resonance (MR) non-contrast cisternography, diffusion-weighted MR imaging (MR-DWI) along with intravoxel-incoherent motion (IVIM) DWI, while evaluating glymphatic function using a standard dynamic contrast-enhanced MR imaging to better understand how water transport and glymphatic function is disrupted after genetic deletion of AQP4. AQP4 KO mice had larger interstitial spaces and total brain volumes resulting in higher water content and reduced CSF space volumes, despite similar CSF production rates and vascular density compared to wildtype mice. The larger interstitial fluid volume likely resulted in increased slow but not fast MR diffusion measures and coincided with reduced glymphatic influx. This markedly altered brain fluid transport in AQP4 KO mice may result from a reduction in glymphatic clearance, leading to enlargement and stagnation of fluid in the interstitial space. Overall, diffusion MR is a useful tool to evaluate glymphatic function and may serve as valuable translational biomarker to study glymphatics in human disease.
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Affiliation(s)
| | - Lauren M Hablitz
- Center for Translational Neuromedicine, University of Rochester Medical CenterRochesterUnited States
| | - Humberto Mestre
- Center for Translational Neuromedicine, University of Rochester Medical CenterRochesterUnited States
- Department of Neurology, University of PennsylvaniaPhiladelphiaUnited States
| | - Michael Giannetto
- Center for Translational Neuromedicine, University of Rochester Medical CenterRochesterUnited States
| | - Ting Du
- Center for Translational Neuromedicine, University of Rochester Medical CenterRochesterUnited States
- School of Pharmacy, China Medical UniversityShenyangChina
| | | | - Lulu Xie
- Center for Translational Neuromedicine, University of Rochester Medical CenterRochesterUnited States
| | - Weiguo Peng
- Center for Translational Neuromedicine, University of CopenhagenCopenhagenDenmark
- Center for Translational Neuromedicine, University of Rochester Medical CenterRochesterUnited States
| | | | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of CopenhagenCopenhagenDenmark
- Center for Translational Neuromedicine, University of Rochester Medical CenterRochesterUnited States
| | - Yuki Mori
- Center for Translational Neuromedicine, University of CopenhagenCopenhagenDenmark
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113
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Brain Waste Removal System and Sleep: Photobiomodulation as an Innovative Strategy for Night Therapy of Brain Diseases. Int J Mol Sci 2023; 24:ijms24043221. [PMID: 36834631 PMCID: PMC9965491 DOI: 10.3390/ijms24043221] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/28/2023] [Accepted: 02/02/2023] [Indexed: 02/10/2023] Open
Abstract
Emerging evidence suggests that an important function of the sleeping brain is the removal of wastes and toxins from the central nervous system (CNS) due to the activation of the brain waste removal system (BWRS). The meningeal lymphatic vessels (MLVs) are an important part of the BWRS. A decrease in MLV function is associated with Alzheimer's and Parkinson's diseases, intracranial hemorrhages, brain tumors and trauma. Since the BWRS is activated during sleep, a new idea is now being actively discussed in the scientific community: night stimulation of the BWRS might be an innovative and promising strategy for neurorehabilitation medicine. This review highlights new trends in photobiomodulation of the BWRS/MLVs during deep sleep as a breakthrough technology for the effective removal of wastes and unnecessary compounds from the brain in order to increase the neuroprotection of the CNS as well as to prevent or delay various brain diseases.
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114
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Bah TM, Siler DA, Ibrahim AH, Cetas JS, Alkayed NJ. Fluid dynamics in aging-related dementias. Neurobiol Dis 2023; 177:105986. [PMID: 36603747 DOI: 10.1016/j.nbd.2022.105986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/22/2022] [Accepted: 12/31/2022] [Indexed: 01/03/2023] Open
Abstract
Recent human and animal model experimental studies revealed novel pathways for fluid movement, immune cell trafficking and metabolic waste clearance in CNS. These studies raise the intriguing possibility that the newly discovered pathways, including the glymphatic system, lymphatic meningeal vessels and skull-brain communication channels, are impaired in aging and neurovascular and neurodegenerative diseases associated with dementia, including Alzheimer's disease (AD) and AD-related dementia. We provide an overview of the glymphatic and dural meningeal lymphatic systems, review current methods and approaches used to study glymphatic flow in humans and animals, and discuss current evidence and controversies related to its role in CNS flow homeostasis under physiological and pathophysiological conditions. Non-invasive imaging approaches are needed to fully understand the mechanisms and pathways driving fluid movement in CNS and their roles across lifespan including healthy aging and aging-related dementia.
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Affiliation(s)
- Thierno M Bah
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA
| | - Dominic A Siler
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR, USA
| | - Aseel H Ibrahim
- Department of Neurosurgery, University of Arizona, Tucson, AZ, USA
| | - Justin S Cetas
- Department of Neurosurgery, University of Arizona, Tucson, AZ, USA
| | - Nabil J Alkayed
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA; Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA.
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115
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Zhou M, Tang S. Effect of a dual orexin receptor antagonist on Alzheimer's disease: Sleep disorders and cognition. Front Med (Lausanne) 2023; 9:984227. [PMID: 36816725 PMCID: PMC9929354 DOI: 10.3389/fmed.2022.984227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 11/18/2022] [Indexed: 02/04/2023] Open
Abstract
Orexin is a neuropeptide produced by the lateral hypothalamus that plays an important role in regulating the sleep-wake cycle. The overexpression of the orexinergic system may be related to the pathology of sleep/wakefulness disorders in Alzheimer's disease (AD). In AD patients, the increase in cerebrospinal fluid orexin levels is associated with parallel sleep deterioration. Dual orexin receptor antagonist (DORA) can not only treat the sleep-wakefulness disorder of AD but also improve the performance of patients with cognitive behavior disorder. It is critical to clarify the role of the orexin system in AD, study its relationship with cognitive decline in AD, and evaluate the safety and efficacy of DORA.
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Affiliation(s)
- Mengzhen Zhou
- Department of Neurology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, Shandong, China
| | - Shi Tang
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China,*Correspondence: Shi Tang
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116
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Xu C, Wang F, Su C, Guo X, Li J, Lin J. Restoration of aquaporin-4 polarization in the spinal glymphatic system by metformin in rats with painful diabetic neuropathy. Neuroreport 2023; 34:190-197. [PMID: 36719843 PMCID: PMC9981323 DOI: 10.1097/wnr.0000000000001880] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 01/09/2023] [Indexed: 02/01/2023]
Abstract
Painful diabetic neuropathy (PDN) is a common complication in patients with diabetes, and its underlying mechanism remains unclear. Aquaporin-4 (AQP4) plays a crucial role in removing metabolic waste in the glymphatic system. In this study, we aimed to explore the relationship between the spinal glymphatic system and the effect of metformin on PDN. Male Sprague-Dawley rats were randomly allocated into the control group ( n = 10), the PDN group ( n = 10), and the metformin group ( n = 10). A high-fat and high-glucose diet combined with low-dose streptozotocin was used to induce PDN rats. We detected the clearance rate of the contrast agent in the spinal cord of each rat by MRI to reflect the function of the glymphatic system. Immunofluorescence was used to detect the localization of perivascular AQP4 in astrocyte endfeet. Furthermore, we measured the expression of AQP4 in the spinal cord by Western blot. Compared with the rats in the control group, PDN rats exhibited enhanced mechanical allodynia, decreased clearance rate of the contrast agent in the spinal glymphatic system, reversed AQP4 polarization, and increased expression of AQP4. After being treated with metformin, the rats showed opposite changes in the above characteristics. The analgesic effect of metformin on PDN may be related to its ability to restore spinal AQP4 polarization, thus promoting the function of the spinal glymphatic system.
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Affiliation(s)
| | | | - Can Su
- Radiology, the Affiliated Hospital of North Sichuan Medical College, Nanchong, China
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117
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Ben-Nejma IRH, Keliris AJ, Vanreusel V, Ponsaerts P, Van der Linden A, Keliris GA. Altered dynamics of glymphatic flow in a mature-onset Tet-off APP mouse model of amyloidosis. Alzheimers Res Ther 2023; 15:23. [PMID: 36707887 PMCID: PMC9883946 DOI: 10.1186/s13195-023-01175-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 01/18/2023] [Indexed: 01/29/2023]
Abstract
BACKGROUND Alzheimer's disease (AD) is an incurable neurodegenerative disorder characterised by the progressive buildup of toxic amyloid-beta (Aβ) and tau protein aggregates eventually leading to cognitive decline. Recent lines of evidence suggest that an impairment of the glymphatic system (GS), a brain waste clearance pathway, plays a key role in the pathology of AD. Moreover, a relationship between GS function and neuronal network integrity has been strongly implicated. Here, we sought to assess the efficacy of the GS in a transgenic Tet-Off APP mouse model of amyloidosis, in which the expression of mutant APP was delayed until maturity, mimicking features of late-onset AD-the most common form of dementia in humans. METHODS To evaluate GS function, we used dynamic contrast-enhanced MRI (DCE-MRI) in 14-month-old Tet-Off APP (AD) mice and aged-matched littermate controls. Brain-wide transport of the Gd-DOTA contrast agent was monitored over time after cisterna magna injection. Region-of-interest analysis and computational modelling were used to assess GS dynamics while characterisation of brain tissue abnormalities at the microscale was performed ex vivo by immunohistochemistry. RESULTS We observed reduced rostral glymphatic flow and higher accumulation of the contrast agent in areas proximal to the injection side in the AD group. Clustering and subsequent computational modelling of voxel time courses revealed significantly lower influx time constants in AD relative to the controls. Ex vivo evaluation showed abundant amyloid plaque burden in the AD group coinciding with extensive astrogliosis and microgliosis. The neuroinflammatory responses were also found in plaque-devoid regions, potentially impacting brain-fluid circulation. CONCLUSIONS In a context resembling late-onset AD in humans, we demonstrate the disruption of glymphatic function and particularly a reduction in brain-fluid influx in the AD group. We conjecture that the hindered circulation of cerebrospinal fluid is potentially caused by wide-spread astrogliosis and amyloid-related obstruction of the normal routes of glymphatic flow resulting in redirection towards caudal regions. In sum, our study highlights the translational potential of alternative approaches, such as targeting brain-fluid circulation as potential therapeutic strategies for AD.
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Affiliation(s)
- Inès R. H. Ben-Nejma
- grid.5284.b0000 0001 0790 3681Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, Wilrijk, 2610 Antwerp, Belgium
| | - Aneta J. Keliris
- grid.5284.b0000 0001 0790 3681Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, Wilrijk, 2610 Antwerp, Belgium
| | - Verdi Vanreusel
- grid.5284.b0000 0001 0790 3681Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, Wilrijk, 2610 Antwerp, Belgium ,Research in Dosimetric Applications, SCK CEN, Boeretang 200, Mol, 2400 Antwerp, Belgium
| | - Peter Ponsaerts
- grid.5284.b0000 0001 0790 3681Laboratory of Experimental Hematology, Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Universiteitsplein 1, Wilrijk, 2610 Antwerp, Belgium
| | - Annemie Van der Linden
- grid.5284.b0000 0001 0790 3681Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, Wilrijk, 2610 Antwerp, Belgium ,grid.5284.b0000 0001 0790 3681μNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
| | - Georgios A. Keliris
- grid.5284.b0000 0001 0790 3681Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, Wilrijk, 2610 Antwerp, Belgium ,grid.5284.b0000 0001 0790 3681μNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium ,grid.4834.b0000 0004 0635 685XInstitute of Computer Science, Foundation for Research and Technology – Hellas (FORTH), Heraklion, Crete Greece
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118
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Vasciaveo V, Iadarola A, Casile A, Dante D, Morello G, Minotta L, Tamagno E, Cicolin A, Guglielmotto M. Sleep fragmentation affects glymphatic system through the different expression of AQP4 in wild type and 5xFAD mouse models. Acta Neuropathol Commun 2023; 11:16. [PMID: 36653878 PMCID: PMC9850555 DOI: 10.1186/s40478-022-01498-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 12/18/2022] [Indexed: 01/20/2023] Open
Abstract
Alzheimer's disease (AD) is characterized by genetic and multifactorial risk factors. Many studies correlate AD to sleep disorders. In this study, we performed and validated a mouse model of AD and sleep fragmentation, which properly mimics a real condition of intermittent awakening. We noticed that sleep fragmentation induces a general acceleration of AD progression in 5xFAD mice, while in wild type mice it affects cognitive behaviors in particular learning and memory. Both these events may be correlated to aquaporin-4 (AQP4) modulation, a crucial player of the glymphatic system activity. In particular, sleep fragmentation differentially affects aquaporin-4 channel (AQP4) expression according to the stage of the disease, with an up-regulation in younger animals, while such change cannot be detected in older ones. Moreover, in wild type mice sleep fragmentation affects cognitive behaviors, in particular learning and memory, by compromising the glymphatic system through the decrease of AQP4. Nevertheless, an in-depth study is needed to better understand the mechanism by which AQP4 is modulated and whether it could be considered a risk factor for the disease development in wild type mice. If our hypotheses are going to be confirmed, AQP4 modulation may represent the convergence point between AD and sleep disorder pathogenic mechanisms.
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Affiliation(s)
- Valeria Vasciaveo
- grid.7605.40000 0001 2336 6580Department of Neuroscience Rita Levi Montalcini, University of Torino, Via Cherasco 15, 10126 Turin, Italy ,grid.7605.40000 0001 2336 6580Neuroscience Institute of Cavalieri Ottolenghi Foundation (NICO), University of Torino, Regione Gonzole 10, 10043 Orbassano, Turin, Italy
| | - Antonella Iadarola
- grid.432329.d0000 0004 1789 4477Department of Neuroscience and Mental Health, AOU Città della Salute e della Scienza, Corso Bramante 88, 10126 Turin, Italy
| | - Antonino Casile
- grid.5602.10000 0000 9745 6549School of Pharmacy, Pharmacology Unit, University of Camerino, Via Madonna delle Carceri, 9, 62032 Camerino, MC Italy
| | - Davide Dante
- grid.7605.40000 0001 2336 6580Neuroscience Institute of Cavalieri Ottolenghi Foundation (NICO), University of Torino, Regione Gonzole 10, 10043 Orbassano, Turin, Italy
| | - Giulia Morello
- grid.7605.40000 0001 2336 6580Department of Neuroscience Rita Levi Montalcini, University of Torino, Via Cherasco 15, 10126 Turin, Italy ,grid.7605.40000 0001 2336 6580Neuroscience Institute of Cavalieri Ottolenghi Foundation (NICO), University of Torino, Regione Gonzole 10, 10043 Orbassano, Turin, Italy
| | - Lorenzo Minotta
- grid.7605.40000 0001 2336 6580Neuroscience Institute of Cavalieri Ottolenghi Foundation (NICO), University of Torino, Regione Gonzole 10, 10043 Orbassano, Turin, Italy
| | - Elena Tamagno
- grid.7605.40000 0001 2336 6580Department of Neuroscience Rita Levi Montalcini, University of Torino, Via Cherasco 15, 10126 Turin, Italy ,grid.7605.40000 0001 2336 6580Neuroscience Institute of Cavalieri Ottolenghi Foundation (NICO), University of Torino, Regione Gonzole 10, 10043 Orbassano, Turin, Italy
| | - Alessandro Cicolin
- grid.7605.40000 0001 2336 6580Department of Neuroscience Rita Levi Montalcini, University of Torino, Via Cherasco 15, 10126 Turin, Italy
| | - Michela Guglielmotto
- grid.7605.40000 0001 2336 6580Department of Neuroscience Rita Levi Montalcini, University of Torino, Via Cherasco 15, 10126 Turin, Italy ,grid.7605.40000 0001 2336 6580Neuroscience Institute of Cavalieri Ottolenghi Foundation (NICO), University of Torino, Regione Gonzole 10, 10043 Orbassano, Turin, Italy
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119
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Choroid Plexus Aquaporins in CSF Homeostasis and the Glymphatic System: Their Relevance for Alzheimer's Disease. Int J Mol Sci 2023; 24:ijms24010878. [PMID: 36614315 PMCID: PMC9821203 DOI: 10.3390/ijms24010878] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/27/2022] [Accepted: 12/27/2022] [Indexed: 01/05/2023] Open
Abstract
The glymphatic system, a fluid-clearance pathway involved in brain waste clearance, is known to be impaired in neurological disorders, including Alzheimer's disease (AD). For this reason, it is important to understand the specific mechanisms and factors controlling glymphatic function. This pathway enables the flow of cerebrospinal fluid (CSF) into the brain and subsequently the brain interstitium, supported by aquaporins (AQPs). Continuous CSF transport through the brain parenchyma is critical for the effective transport and drainage of waste solutes, such as toxic proteins, through the glymphatic system. However, a balance between CSF production and secretion from the choroid plexus, through AQP regulation, is also needed. Thus, any condition that affects CSF homeostasis will also interfere with effective waste removal through the clearance glymphatic pathway and the subsequent processes of neurodegeneration. In this review, we highlight the role of AQPs in the choroid plexus in the modulation of CSF homeostasis and, consequently, the glymphatic clearance pathway, with a special focus on AD.
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120
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Shirolapov IV, Zakharov AV, Smirnova DA, Lyamin AV, Gayduk AY. [The significance of the glymphatic pathway in the relationship between the sleep-wake cycle and neurodegenerative diseases]. Zh Nevrol Psikhiatr Im S S Korsakova 2023; 123:31-36. [PMID: 37796065 DOI: 10.17116/jnevro202312309131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/06/2023]
Abstract
Selective and progressive death of neurons is a characteristic feature of the process of neurodegeneration and leads to corresponding neuronal dysfunctions. Neurodegenerative diseases represent a heterogeneous group of clinically distinct disorders with similar molecular mechanisms of pathogenesis. They are based on the processes of abnormal aggregation of proteins, the formation of fibrillary insoluble structures and their deposition in the form of histopathological inclusions in the tissues of the nervous system. Disturbance of homeostatic functions that regulate neuronal ion and energy metabolism, biosynthesis and degradation of proteins and nucleotides, chronic hypoxia and the penetration of toxic and inflammatory substances into the brain from the bloodstream not only cause metabolic changes associated with age and disorders in the sleep-wake cycle, but also contribute to the development of neurodegenerative diseases. In animal studies, clearance pathways have been identified in which solutes and specific tracers are excreted perivascular into the meningeal lymphatics. The glymphatic pathway promotes the removal of metabolites, including Aβ amyloid and tau protein, from the parenchymal extracellular space of the brain. The glymphatic system is discussed to be more efficient during natural sleep, and fluid dynamics through this pathway exhibit daily fluctuations and are under circadian control. This review systematizes the key aspects and the data of recent research on the role of the glymphatic pathway and astroglial AQP-4 as its main determinant in maintaining homeostatic fluid circulation in the brain in normal and pathological conditions, in particular in relation to the regulatory role of the sleep-wake cycle and in development of neurodegeneration.
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Affiliation(s)
| | | | | | - A V Lyamin
- Samara State Medical University, Samara, Russia
| | - A Ya Gayduk
- Samara State Medical University, Samara, Russia
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121
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Yan JH, Wang YJ, Sun YR, Pei YH, Ma HW, Mu YK, Qin LH. The lymphatic drainage systems in the brain: a novel target for ischemic stroke? Neural Regen Res 2023; 18:485-491. [DOI: 10.4103/1673-5374.346484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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122
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Abstract
Aquaporins (AQP) working as membrane channels facilitated water transport, play vital roles in various physiological progress including cell migration, energy metabolism, inflammation, etc. They are quite important drug targets, but elusive for discovery due to their undruggable properties. In this chapter, we summarized most fluently used methods for screening AQP inhibitors, including cell swelling assay, cell shrinking assay, and stopped-flow assay. And three classes of AQP inhibitors have been discussed, including metal-related inhibitors, quaternary ammonium salts, and small molecule inhibitors which further divided into four parts, sulfanilamide analogies, TGN-020, antiepileptic drugs, and others. It has been suggested that although they showed inhibition effects on AQP1, AQP3, AQP4, AQP7, or AQP9 in some researches, none of them could be asserted as AQP inhibitors to some extent. Discovering AQP inhibitors is a big challenge, but if successful, it will be a great contribution for human health.
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Affiliation(s)
- Shuyuan Wang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | | | - Baoxue Yang
- School of Basic Medical Sciences, Peking University, Beijing, China.
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123
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Huang P, Zhang M. Magnetic Resonance Imaging Studies of Neurodegenerative Disease: From Methods to Translational Research. Neurosci Bull 2023; 39:99-112. [PMID: 35771383 PMCID: PMC9849544 DOI: 10.1007/s12264-022-00905-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 05/07/2022] [Indexed: 01/22/2023] Open
Abstract
Neurodegenerative diseases (NDs) have become a significant threat to an aging human society. Numerous studies have been conducted in the past decades to clarify their pathologic mechanisms and search for reliable biomarkers. Magnetic resonance imaging (MRI) is a powerful tool for investigating structural and functional brain alterations in NDs. With the advantages of being non-invasive and non-radioactive, it has been frequently used in both animal research and large-scale clinical investigations. MRI may serve as a bridge connecting micro- and macro-level analysis and promoting bench-to-bed translational research. Nevertheless, due to the abundance and complexity of MRI techniques, exploiting their potential is not always straightforward. This review aims to briefly introduce research progress in clinical imaging studies and discuss possible strategies for applying MRI in translational ND research.
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Affiliation(s)
- Peiyu Huang
- Department of Radiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009 China
| | - Minming Zhang
- Department of Radiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310009 China
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124
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Shirolapov IV, Zakharov AV, Smirnova DA, Lyamin AV, Gayduk AJ. [The significance of glymphatic pathway in the relationship between the sleep-wake cycle and neurodegenerative diseases]. Zh Nevrol Psikhiatr Im S S Korsakova 2023; 123:42-47. [PMID: 37966438 DOI: 10.17116/jnevro202312310142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2023]
Abstract
Selective and progressive death of neurons is a characteristic feature of the process of neurodegeneration and leads to corresponding neuronal dysfunctions. Neurodegenerative diseases represent a heterogeneous group of clinically distinct disorders with similar molecular mechanisms of pathogenesis. They are based on the processes of abnormal aggregation of proteins, the formation of fibrillary insoluble structures and their deposition in the form of histopathological inclusions in the tissues of the nervous system. Disturbance of homeostatic functions that regulate neuronal ion and energy metabolism, biosynthesis and degradation of proteins and nucleotides, chronic hypoxia and the penetration of toxic and inflammatory substances into the brain from the bloodstream not only cause metabolic changes associated with age and disorders in the sleep-wake cycle, but also contribute to the development of neurodegenerative diseases. In animal studies, clearance pathways have been identified in which solutes and specific tracers are excreted perivascular into the meningeal lymphatics. The glymphatic pathway promotes the removal of metabolites, including Aβ amyloid and tau protein, from the parenchymal extracellular space of the brain. The glymphatic system is discussed to be more efficient during natural sleep, and fluid dynamics through this pathway exhibit daily fluctuations and are under circadian control. This review systematizes the key aspects and scientific data of recent studies on the role of the glymphatic pathway and astroglial AQP-4 as its main determinant in maintaining homeostatic fluid circulation in the brain in normal and pathological conditions, in particular in relation to the regulatory role of the sleep-wake cycle and in development of neurodegeneration.
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Affiliation(s)
| | | | | | - A V Lyamin
- Samara State Medical University, Samara, Russia
| | - A J Gayduk
- Samara State Medical University, Samara, Russia
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125
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Mitrofanis J, Valverde A, Hamilton C, Moro C, Billeres M, Magistretti P. Lights at night: does photobiomodulation improve sleep? Neural Regen Res 2023; 18:474-477. [DOI: 10.4103/1673-5374.350191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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126
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Hsu JL, Wei YC, Toh CH, Hsiao IT, Lin KJ, Yen TC, Liao MF, Ro LS. Magnetic Resonance Images Implicate That Glymphatic Alterations Mediate Cognitive Dysfunction in Alzheimer Disease. Ann Neurol 2023; 93:164-174. [PMID: 36214568 PMCID: PMC10091747 DOI: 10.1002/ana.26516] [Citation(s) in RCA: 36] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 10/02/2022] [Accepted: 10/02/2022] [Indexed: 02/05/2023]
Abstract
OBJECTIVE The glymphatic system cleans amyloid and tau proteins from the brain in animal studies of Alzheimer disease (AD). However, there is no direct evidence showing this in humans. METHODS Participants (n = 50, 62.6 ± 5.4 years old, 36 women) with AD and normal controls underwent amyloid positron emission tomography (PET), tau PET, structural T1-weighted magnetic resonance imaging, and neuropsychological evaluation. Whole-brain glymphatic activity was measured by diffusion tensor image analysis along the perivascular space (DTI-ALPS). RESULTS ALPS-indexes showed negative correlations with deposition of amyloid and tau on PET images and positive correlations with cognitive scores even after adjusting for age, sex, years of education, and APOE4 genotype covariates in multiple AD-related brain regions (all p < 0.05). Mediation analysis showed that ALPS-index acted as a significant mediator between regional standardized uptake value ratios of amyloid and tau images and cognitive dysfunction even after correcting for multiple covariates in AD-related brain regions. These regions are responsible for attention, memory, and executive function, which are vulnerable to sleep deprivation. INTERPRETATION Glymphatic system activity may act as a significant mediator in AD-related cognitive dysfunction even after adjusting for multiple covariates and gray matter volumes. ALPS-index may provide useful disease progression or treatment biomarkers for patients with AD as an indicator of modulation of glymphatic activity. ANN NEUROL 2023;93:164-174.
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Affiliation(s)
- Jung-Lung Hsu
- Department of Neurology, New Taipei Municipal TuCheng Hospital, New Taipei City, Taiwan.,Department of Neurology, Chang Gung Memorial Hospital Linkou Medical Center Neuroscience Research Center, and College of Medicine, Chang-Gung University, Taoyuan, Taiwan.,Taipei Medical University, Graduate Institute of Humanities in Medicine and Research Center for Brain and Consciousness, Shuang Ho Hospital, Taipei, Taiwan
| | - Yi-Chia Wei
- Department of Neurology, Chang Gung Memorial Hospital, Keelung, Taiwan.,Community Medicine Research Center, Chang Gung Memorial Hospital, Keelung, Taiwan.,Institute of Neuroscience, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Cheng Hong Toh
- Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital at Linkou, Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Ing-Tsung Hsiao
- Department of Nuclear Medicine and Center for Advanced Molecular Imaging and Translation, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Department of Medical Imaging and Radiological Sciences and Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan
| | - Kun-Ju Lin
- Department of Nuclear Medicine and Center for Advanced Molecular Imaging and Translation, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Department of Medical Imaging and Radiological Sciences and Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan
| | | | - Ming-Feng Liao
- Department of Neurology, Chang Gung Memorial Hospital Linkou Medical Center Neuroscience Research Center, and College of Medicine, Chang-Gung University, Taoyuan, Taiwan
| | - Long-Sun Ro
- Department of Neurology, Chang Gung Memorial Hospital Linkou Medical Center Neuroscience Research Center, and College of Medicine, Chang-Gung University, Taoyuan, Taiwan
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127
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Chachaj A, Gąsiorowski K, Szuba A, Sieradzki A, Leszek J. The Lymphatic System In The Brain Clearance Mechanisms - New Therapeutic Perspectives For Alzheimer's Disease. Curr Neuropharmacol 2023; 21:380-391. [PMID: 35410605 PMCID: PMC10190136 DOI: 10.2174/1570159x20666220411091332] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 03/05/2022] [Accepted: 04/06/2022] [Indexed: 11/22/2022] Open
Abstract
Alzheimer's disease (AD) is the most common cause of dementia worldwide. Pathological deposits of neurotoxic proteins within the brain, such as amyloid-ß and hyperphosphorylated tau tangles, are the prominent features in AD. According to recent studies, the newly discovered brain lymphatic system was demonstrated to be crucial in the clearance of metabolic macromolecules from the brain. Meningeal lymphatic vessels located in the dura mater drain the fluid, macromolecules, and immune cells from cerebrospinal fluid (CSF) and transport them, as lymph, to the deep cervical lymph nodes. The lymphatic system provides the perivascular exchange of CSF with interstitial fluid (ISF) and ensures the homeostasis of neuronal interstitial space. In this review, we aim to summarize recent findings on the role of the lymphatic system in AD pathophysiology and discuss possible therapeutic perspectives, targeting the lymphatic clearance mechanisms within the brain.
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Affiliation(s)
- Angelika Chachaj
- Department of Angiology, Hypertension and Diabetology, Wroclaw Medical University, Wroclaw, Poland
| | | | - Andrzej Szuba
- Department of Angiology, Hypertension and Diabetology, Wroclaw Medical University, Wroclaw, Poland
| | - Adrian Sieradzki
- Department of Nervous System Diseases, Wroclaw Medical University, Wroclaw, Poland
| | - Jerzy Leszek
- Department of Psychiatry, Wroclaw Medical University, Wroclaw, Poland
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128
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Xiao M, Hou J, Xu M, Li S, Yang B. Aquaporins in Nervous System. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1398:99-124. [PMID: 36717489 DOI: 10.1007/978-981-19-7415-1_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Aquaporins (AQPs) mediate water flux between the four distinct water compartments in the central nervous system (CNS). In the present chapter, we mainly focus on the expression and function of the nine AQPs expressed in the CNS, which include five members of aquaporin subfamily: AQP1, AQP4, AQP5, AQP6, and AQP8; three members of aquaglyceroporin subfamily: AQP3, AQP7, and AQP9; and one member of superaquaporin subfamily: AQP11. In addition, AQP1, AQP2, and AQP4 expressed in the peripheral nervous system are also reviewed. AQP4, the predominant water channel in the CNS, is involved both in the astrocyte swelling of cytotoxic edema and the resolution of vasogenic edema and is of pivotal importance in the pathology of brain disorders such as neuromyelitis optica, brain tumors, and neurodegenerative disorders. Moreover, AQP4 has been demonstrated as a functional regulator of recently discovered glymphatic system that is a main contributor to clearance of toxic macromolecule from the brain. Other AQPs are also involved in a variety of important physiological and pathological process in the brain. It has been suggested that AQPs could represent an important target in treatment of brain disorders like cerebral edema. Future investigations are necessary to elucidate the pathological significance of AQPs in the CNS.
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Affiliation(s)
- Ming Xiao
- Jiangsu Province, Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, Nanjing, China
| | - Jiaoyu Hou
- Department of Geriatrics, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Mengmeng Xu
- Basic Medical College, Guizhou University of Traditional Chinese Medicine, Guiyang, China
| | - Shao Li
- Department of Physiology, Dalian Medical University, Dalian, China
| | - Baoxue Yang
- School of Basic Medical Sciences, Peking University, Beijing, China.
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129
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Guo X, Zhang G, Peng Q, Huang L, Zhang Z, Zhang Z. Emerging Roles of Meningeal Lymphatic Vessels in Alzheimer's Disease. J Alzheimers Dis 2023; 94:S355-S366. [PMID: 36683509 PMCID: PMC10473149 DOI: 10.3233/jad-221016] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/17/2022] [Indexed: 01/22/2023]
Abstract
Meningeal lymphatic vessels (mLVs), the functional lymphatic system present in the meninges, are the key drainage route responsible for the clearance of molecules, immune cells, and cellular debris from the cerebrospinal fluid and interstitial fluid into deep cervical lymph nodes. Aging and ApoE4, the two most important risk factors for Alzheimer's disease (AD), induce mLV dysfunction, decrease cerebrospinal fluid influx and outflux, and exacerbate amyloid pathology and cognitive dysfunction. Dysfunction of mLVs results in the deposition of metabolic products, accelerates neuroinflammation, and promotes the release of pro-inflammatory cytokines in the brain. Thus, mLVs represent a novel therapeutic target for treating neurodegenerative and neuroinflammatory diseases. This review aims to summarize the structure and function of mLVs and to discuss the potential effect of aging and ApoE4 on mLV dysfunction, as well as their roles in the pathogenesis of AD.
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Affiliation(s)
- Xiaodi Guo
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Guoxin Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Qinyu Peng
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Liqin Huang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Zhaohui Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Zhentao Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
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130
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Cerebral Folate Metabolism in Post-Mortem Alzheimer's Disease Tissues: A Small Cohort Study. Int J Mol Sci 2022; 24:ijms24010660. [PMID: 36614107 PMCID: PMC9820589 DOI: 10.3390/ijms24010660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 12/27/2022] [Indexed: 01/03/2023] Open
Abstract
We investigated the cerebral folate system in post-mortem brains and matched cerebrospinal fluid (CSF) samples from subjects with definite Alzheimer's disease (AD) (n = 21) and neuropathologically normal brains (n = 21) using immunohistochemistry, Western blot and dot blot. In AD the CSF showed a significant decrease in 10-formyl tetrahydrofolate dehydrogenase (FDH), a critical folate binding protein and enzyme in the CSF, as well as in the main folate transporter, folate receptor alpha (FRα) and folate. In tissue, we found a switch in the pathway of folate supply to the cerebral cortex in AD compared to neurologically normal brains. FRα switched from entry through FDH-positive astrocytes in normal, to entry through glial fibrillary acidic protein (GFAP)-positive astrocytes in the AD cortex. Moreover, this switch correlated with an apparent change in metabolic direction to hypermethylation of neurons in AD. Our data suggest that the reduction in FDH in CSF prohibits FRα-folate entry via FDH-positive astrocytes and promotes entry through the GFAP pathway directly to neurons for hypermethylation. This data may explain some of the cognitive decline not attributable to the loss of neurons alone and presents a target for potential treatment.
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131
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Liu G, Ladrón-de-Guevara A, Izhiman Y, Nedergaard M, Du T. Measurements of cerebrospinal fluid production: a review of the limitations and advantages of current methodologies. Fluids Barriers CNS 2022; 19:101. [PMID: 36522656 PMCID: PMC9753305 DOI: 10.1186/s12987-022-00382-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 10/13/2022] [Indexed: 12/23/2022] Open
Abstract
Cerebrospinal fluid (CSF) is an essential and critical component of the central nervous system (CNS). According to the concept of the "third circulation" originally proposed by Cushing, CSF is mainly produced by the choroid plexus and subsequently leaves the cerebral ventricles via the foramen of Magendie and Luschka. CSF then fills the subarachnoid space from whence it disperses to all parts of the CNS, including the forebrain and spinal cord. CSF provides buoyancy to the submerged brain, thus protecting it against mechanical injury. CSF is also transported via the glymphatic pathway to reach deep interstitial brain regions along perivascular channels; this CSF clearance pathway promotes transport of energy metabolites and signaling molecules, and the clearance of metabolic waste. In particular, CSF is now intensively studied as a carrier for the removal of proteins implicated in neurodegeneration, such as amyloid-β and tau. Despite this key function of CSF, there is little information about its production rate, the factors controlling CSF production, and the impact of diseases on CSF flux. Therefore, we consider it to be a matter of paramount importance to quantify better the rate of CSF production, thereby obtaining a better understanding of CSF dynamics. To this end, we now review the existing methods developed to measure CSF production, including invasive, noninvasive, direct, and indirect methods, and MRI-based techniques. Depending on the methodology, estimates of CSF production rates in a given species can extend over a ten-fold range. Throughout this review, we interrogate the technical details of CSF measurement methods and discuss the consequences of minor experimental modifications on estimates of production rate. Our aim is to highlight the gaps in our knowledge and inspire the development of more accurate, reproducible, and less invasive techniques for quantitation of CSF production.
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Affiliation(s)
- Guojun Liu
- Department of Neurosurgery, The Fourth Affiliated Hospital of China Medical University, Shenyang, 110032, China
- School of Pharmacy, China Medical University, Shenyang, 110122, China
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
- Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Antonio Ladrón-de-Guevara
- Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Yara Izhiman
- Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark.
- Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, 14642, USA.
| | - Ting Du
- School of Pharmacy, China Medical University, Shenyang, 110122, China.
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark.
- Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, 14642, USA.
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132
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Pham W, Lynch M, Spitz G, O’Brien T, Vivash L, Sinclair B, Law M. A critical guide to the automated quantification of perivascular spaces in magnetic resonance imaging. Front Neurosci 2022; 16:1021311. [PMID: 36590285 PMCID: PMC9795229 DOI: 10.3389/fnins.2022.1021311] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 11/16/2022] [Indexed: 12/15/2022] Open
Abstract
The glymphatic system is responsible for waste clearance in the brain. It is comprised of perivascular spaces (PVS) that surround penetrating blood vessels. These spaces are filled with cerebrospinal fluid and interstitial fluid, and can be seen with magnetic resonance imaging. Various algorithms have been developed to automatically label these spaces in MRI. This has enabled volumetric and morphological analyses of PVS in healthy and disease cohorts. However, there remain inconsistencies between PVS measures reported by different methods of automated segmentation. The present review emphasizes that importance of voxel-wise evaluation of model performance, mainly with the Sørensen Dice similarity coefficient. Conventional count correlations for model validation are inadequate if the goal is to assess volumetric or morphological measures of PVS. The downside of voxel-wise evaluation is that it requires manual segmentations that require large amounts of time to produce. One possible solution is to derive these semi-automatically. Additionally, recommendations are made to facilitate rigorous development and validation of automated PVS segmentation models. In the application of automated PVS segmentation tools, publication of image quality metrics, such as the contrast-to-noise ratio, alongside descriptive statistics of PVS volumes and counts will facilitate comparability between studies. Lastly, a head-to-head comparison between two algorithms, applied to two cohorts of astronauts reveals how results can differ substantially between techniques.
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Affiliation(s)
- William Pham
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Miranda Lynch
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Gershon Spitz
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
- Monash-Epworth Rehabilitation Research Centre, Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Melbourne, VIC, Australia
| | - Terence O’Brien
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
- Department of Neurology, Alfred Hospital, Melbourne, VIC, Australia
- Department of Medicine, The Royal Melbourne Hospital, University of Melbourne, Melbourne, VIC, Australia
- Department of Neurology, The Royal Melbourne Hospital, University of Melbourne, Melbourne, VIC, Australia
| | - Lucy Vivash
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
- Department of Neurology, Alfred Hospital, Melbourne, VIC, Australia
- Department of Medicine, The Royal Melbourne Hospital, University of Melbourne, Melbourne, VIC, Australia
- Department of Neurology, The Royal Melbourne Hospital, University of Melbourne, Melbourne, VIC, Australia
| | - Benjamin Sinclair
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
- Department of Neurology, Alfred Hospital, Melbourne, VIC, Australia
- Department of Medicine, The Royal Melbourne Hospital, University of Melbourne, Melbourne, VIC, Australia
| | - Meng Law
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
- Department of Radiology, Alfred Health Hospital, Melbourne, VIC, Australia
- Department of Electrical and Computer Systems Engineering, Monash University, Melbourne, VIC, Australia
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133
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Kang KM, Byun MS, Yi D, Lee KH, Kim M, Ahn H, Jung G, Lee J, Kim YK, Lee Y, Sohn C, Lee DY. Enlarged perivascular spaces are associated with decreased brain tau deposition. CNS Neurosci Ther 2022; 29:577-586. [PMID: 36468423 PMCID: PMC9873511 DOI: 10.1111/cns.14040] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 11/11/2022] [Accepted: 11/14/2022] [Indexed: 12/10/2022] Open
Abstract
AIMS The aim of this study was to investigate the associations of enlarged perivascular spaces (EPVS) in the basal ganglia (BG) and centrum semiovale (CSO) with beta-amyloid (Aβ) and tau deposition in older adults with a diverse cognitive spectrum. METHODS A total of 163 (68 cognitively normal and 95 cognitively impaired) older participants underwent [11 C] Pittsburgh compound B and [18 F] AV-1451 PET, and MRI. EPVS in the BG and CSO and other small vessel disease markers, such as white matter hyperintensities, lacunes, and deep and lobar microbleeds, were assessed. RESULTS Increased EPVS in the BG showed a significant association with lower cerebral tau deposition, even after controlling for other small vessel disease markers. Further exploratory analyses showed that this association was significant in cognitively impaired, Aβ-positive, or APOE4-positive individuals, but not significant in the cognitively normal, Aβ-negative, or APOE4-negative participants. In contrast to EPVS in the BG, EPVS in the CSO did not have any relationship with cerebral tau deposition. In addition, none of the two types of EPVS were associated with cerebral Aβ deposition. CONCLUSION Brain tau deposition appears to be reduced with increased EPVS in the BG, especially in individuals with cognitive impairment, pathological amyloid burden, or genetic Alzheimer's disease risk.
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Affiliation(s)
- Koung Mi Kang
- Department of RadiologySeoul National University HospitalSeoulKorea,Department of RadiologySeoul National University College of MedicineSeoulKorea
| | - Min Soo Byun
- Department of NeuropsychiatrySeoul National University College of MedicineSeoulKorea,Department of NeuropsychiatrySeoul National University HospitalSeoulKorea
| | - Dahyun Yi
- Biomedical Research Institute, Seoul National University HospitalSeoulKorea
| | - Kyung Hoon Lee
- Department of RadiologySeoul National University HospitalSeoulKorea
| | - Min Jung Kim
- Department of NeuropsychiatrySeoul National University HospitalSeoulKorea
| | - Hyejin Ahn
- Department of NeuropsychiatrySeoul National University HospitalSeoulKorea
| | - Gijung Jung
- Department of NeuropsychiatrySeoul National University HospitalSeoulKorea
| | - Jun‐Young Lee
- Department of NeuropsychiatrySeoul National University College of MedicineSeoulKorea,Department of NeuropsychiatrySMG‐SNU Boramae Medical CenterSeoulKorea
| | - Yu Kyeong Kim
- Department of Nuclear MedicineSMG‐SNU Boramae Medical CenterSeoulKorea
| | - Yun‐Sang Lee
- Department of Nuclear MedicineSeoul National University College of MedicineSeoulKorea
| | - Chul‐Ho Sohn
- Department of RadiologySeoul National University HospitalSeoulKorea,Department of RadiologySeoul National University College of MedicineSeoulKorea
| | - Dong Young Lee
- Department of NeuropsychiatrySeoul National University College of MedicineSeoulKorea,Department of NeuropsychiatrySeoul National University HospitalSeoulKorea,Institute of Human Behavioral MedicineMedical Research Center Seoul National UniversitySeoulKorea
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134
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Ruan J, McKee KK, Yurchenco PD, Yao Y. Exogenous laminin exhibits a unique vascular pattern in the brain via binding to dystroglycan and integrins. Fluids Barriers CNS 2022; 19:97. [PMID: 36463265 PMCID: PMC9719645 DOI: 10.1186/s12987-022-00396-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 11/28/2022] [Indexed: 12/07/2022] Open
Abstract
BACKGROUND Unlike other proteins that exhibit a diffusion pattern after intracerebral injection, laminin displays a vascular pattern. It remains unclear if this unique vascular pattern is caused by laminin-receptor interaction or laminin self-assembly. METHODS We compared the distribution of various wild-type laminin isoforms in the brain after intracerebral injection. To determine what causes the unique vascular pattern of laminin in the brain, laminin mutants with impaired receptor-binding and/or self-assembly activities and function-blocking antibodies to laminin receptors were used. In addition, the dynamics of laminin distribution and elimination were examined at multiple time points after intracerebral injection. RESULTS We found that β2-containing laminins had higher affinity for the vessels compared to β1-containing laminins. In addition, laminin mutants lacking receptor-binding domains but not that lacking self-assembly capability showed substantially reduced vascular pattern. Consistent with this finding, dystroglycan (DAG1) function-blocking antibody significantly reduced the vascular pattern of wild-type laminin-111. Although failed to affect the vascular pattern when used alone, integrin-β1 function-blocking antibody further decreased the vascular pattern when combined with DAG1 antibody. EDTA, which impaired laminini-DAG1 interaction by chelating Ca2+, also attenuated the vascular pattern. Immunohistochemistry revealed that laminins were predominantly located in the perivascular space in capillaries and venules/veins but not arterioles/arteries. The time-course study showed that laminin mutants with impaired receptor-engaging activity were more efficiently eliminated from the brain compared to their wild-type counterparts. Concordantly, significantly higher levels of mutant laminins were detected in the cerebral-spinal fluid (CSF). CONCLUSIONS These findings suggest that intracerebrally injected laminins are enriched in the perivascular space in a receptor (DAG1/integrin)-dependent rather than self-assembly-dependent manner and eliminated from the brain mainly via the perivascular clearance system.
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Affiliation(s)
- Jingsong Ruan
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, 12901 Bruce B. Downs Blvd., MDC 8, Tampa, FL, 33612, USA
| | - Karen K McKee
- Department of Pathology and Laboratory Medicine, Rutgers University-Robert W. Johnson Medical School, Piscataway, NJ, USA
| | - Peter D Yurchenco
- Department of Pathology and Laboratory Medicine, Rutgers University-Robert W. Johnson Medical School, Piscataway, NJ, USA
| | - Yao Yao
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, 12901 Bruce B. Downs Blvd., MDC 8, Tampa, FL, 33612, USA.
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135
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Gu S, Li Y, Jiang Y, Huang JH, Wang F. Glymphatic Dysfunction Induced Oxidative Stress and Neuro-Inflammation in Major Depression Disorders. Antioxidants (Basel) 2022; 11:2296. [PMID: 36421482 PMCID: PMC9687220 DOI: 10.3390/antiox11112296] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/08/2022] [Accepted: 11/18/2022] [Indexed: 07/30/2023] Open
Abstract
Major Depression disorder (MDD) is a potentially life-threatening mental illness, however, many patients have a poor response to current treatments. Recent studies have suggested that stress- or trauma-induced oxidative stress and inflammation could be important factors involved in the development of MDD, but the mechanisms remain unclear. We showed that the glymphatic system is a recently discovered structure in the brain that may be involved in the clearance of large molecular and cell debris in extracellular space. In addition, the glymphatic system can help with the removal of reactive oxygen species (ROS) and cytokines such as IL-1β and HIF-1α. Glymphatic impairment can lead to ROS accumulation in the microenvironment, inducing cellular injury signaling and activating NLRP3 in microglia to induce inflammation and, thus, many brain diseases, including psychiatric disorders. Therefore, trauma-induced glymphatic impairment could induce oxidative stress and inflammation, and thus MDD. This paper will review recent advances with regard to stress-induced glymphatic system impairment and ROS-mediated inflammation in MDD.
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Affiliation(s)
- Simeng Gu
- Department of Neurology, The Affiliated Hospital of Jiangsu University, Jiangsu University, Zhenjiang 212001, China
- Department of Psychology, Medical School, Jiangsu University, Zhenjiang 210023, China
| | - Yumeng Li
- Department of Neurology, The Affiliated Hospital of Jiangsu University, Jiangsu University, Zhenjiang 212001, China
- Department of Psychology, Medical School, Jiangsu University, Zhenjiang 210023, China
| | - Yao Jiang
- Institute of Brain and Psychological Sciences, Sichuan Normal University, Chengdu 610066, China
| | - Jason H. Huang
- Department of Neurosurgery, Baylor Scott & White Health, Temple, TX 79409, USA
- Department of Surgery, College of Medicine, Texas A & M University, Temple, TX 79409, USA
| | - Fushun Wang
- Institute of Brain and Psychological Sciences, Sichuan Normal University, Chengdu 610066, China
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136
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Hier DB, Azizi S, Thimgan MS, Wunsch DC. Tau kinetics in Alzheimer's disease. Front Aging Neurosci 2022; 14:1055170. [PMID: 36437992 PMCID: PMC9682289 DOI: 10.3389/fnagi.2022.1055170] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 10/27/2022] [Indexed: 07/20/2023] Open
Abstract
The cytoskeletal protein tau is implicated in the pathogenesis of Alzheimer's disease which is characterized by intra-neuronal neurofibrillary tangles containing abnormally phosphorylated insoluble tau. Levels of soluble tau are elevated in the brain, the CSF, and the plasma of patients with Alzheimer's disease. To better understand the causes of these elevated levels of tau, we propose a three-compartment kinetic model (brain, CSF, and plasma). The model assumes that the synthesis of tau follows zero-order kinetics (uncorrelated with compartmental tau levels) and that the release, absorption, and clearance of tau is governed by first-order kinetics (linearly related to compartmental tau levels). Tau that is synthesized in the brain compartment can be released into the interstitial fluid, catabolized, or retained in neurofibrillary tangles. Tau released into the interstitial fluid can mix with the CSF and eventually drain to the plasma compartment. However, losses of tau in the drainage pathways may be significant. The kinetic model estimates half-life of tau in each compartment (552 h in the brain, 9.9 h in the CSF, and 10 h in the plasma). The kinetic model predicts that an increase in the neuronal tau synthesis rate or a decrease in tau catabolism rate best accounts for observed increases in tau levels in the brain, CSF, and plasma found in Alzheimer's disease. Furthermore, the model predicts that increases in brain half-life of tau in Alzheimer's disease should be attributed to decreased tau catabolism and not to increased tau synthesis. Most clearance of tau in the neuron occurs through catabolism rather than release to the CSF compartment. Additional experimental data would make ascertainment of the model parameters more precise.
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Affiliation(s)
- Daniel B. Hier
- Applied Computational Intelligence Laboratory, Department of Electrical & Computer Engineering, Missouri University of Science & Technology, Rolla, MO, United States
- Department of Neurology and Rehabilitation, University of Illinois at Chicago, Chicago, IL, United States
| | - Sima Azizi
- Applied Computational Intelligence Laboratory, Department of Electrical & Computer Engineering, Missouri University of Science & Technology, Rolla, MO, United States
| | - Matthew S. Thimgan
- Department of Biological Sciences, Missouri University of Science & Technology, Rolla, MO, United States
| | - Donald C. Wunsch
- Applied Computational Intelligence Laboratory, Department of Electrical & Computer Engineering, Missouri University of Science & Technology, Rolla, MO, United States
- ECCS Division, National Science Foundation, Alexandria, VA, United States
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Abstract
PURPOSE OF REVIEW The purpose of this review article is to summarize the current in-vivo imaging techniques for the evaluation of the glymphatic function and discuss the factors influencing the glymphatic function and research directions in the future. RECENT FINDINGS The glymphatic system allows the clearance of metabolic waste from the central nervous system (CNS). The glymphatic pathway has been investigated using intrathecal or intravenous injection of a gadolinium-based contrast agent (GBCA) on MRI, so-called glymphatic MRI. The glymphatic MRI indirectly visualizes the dynamic CSF flow and evaluated the glymphatic function in the animal and human models. Several clinical and preclinical studies using glymphatic MRI have confirmed that the glymphatic function is impaired in neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, and idiopathic normal pressure hydrocephalus. Furthermore, physiologic process such as sleep facilitates the glymphatic clearance, thus clearing accumulation of protein deposition, such as amyloid or tau, potentially delaying the progression of neurodegenerative diseases. SUMMARY The glymphatic system plays a crucial role in clearing metabolic wastes in the brain. Glymphatic MR imaging using GBCA administration serves as a functional imaging tool to measure the glymphatic function and investigate various pathophysiologies of neurodegenerative diseases.
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Affiliation(s)
- Hyochul Lee
- Interdisciplinary Program in Cancer Biology, Seoul National University College of Medicine
- Department of Radiology, Seoul National University College of Medicine, and Seoul National University Hospital
| | - Seung Hong Choi
- Interdisciplinary Program in Cancer Biology, Seoul National University College of Medicine
- Department of Radiology, Seoul National University College of Medicine, and Seoul National University Hospital
- Center for Nanoparticle Research, Institute for Basic Science, and School of Chemical and Biological Engineering, Seoul National University, Seoul, Korea
| | - Yoshimi Anzai
- Department of Radiology and Imaging Sciences, University of Utah School of Medicine, Salt Lake City, Utah, USA
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138
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Lapshina KV, Abramova YY, Guzeev MA, Ekimova IV. TGN-020, an Inhibitor of the Water Channel Aquaporin-4, Accelerates Nigrostriatal Neurodegeneration in the Rat Model of Parkinson’s Disease. J EVOL BIOCHEM PHYS+ 2022. [DOI: 10.1134/s0022093022060308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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139
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He XZ, Li X, Li ZH, Meng JC, Mao RT, Zhang XK, Zhang RT, Huang HL, Gui Q, Xu GY, Wang LH. High-resolution 3D demonstration of regional heterogeneity in the glymphatic system. J Cereb Blood Flow Metab 2022; 42:2017-2031. [PMID: 35786032 PMCID: PMC9580176 DOI: 10.1177/0271678x221109997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Accumulating evidence indicates that the glymphatic system has a critical role in maintaining brain homeostasis. However, the detailed anatomy of the glymphatic pathway is not well understood, mostly due to a lack of high spatial resolution 3D visualization. In this study, a fluorescence micro-optical sectioning tomography (fMOST) was used to characterize the glymphatic architecture in the mouse brain. At 30 and 120 min after intracisternal infusion with fluorescent dextran (Dex-3), lectin was injected to stain the cerebral vasculature. Using fMOST, a high-resolution 3D dataset of the brain-wide distribution of Dex-3 was acquired. Combined with fluorescence microscopy and microplate array, the heterogeneous glymphatic flow and the preferential irrigated regions were identified. These cerebral regions containing large-caliber penetrating arteries and/or adjacent to the subarachnoid space had more robust CSF flow compared to other regions. Moreover, the major glymphatic vessels for CSF influx and fluid efflux in the entire brain were shown in 3D. This study demonstrates the regional heterogeneity in the glymphatic system and provides an anatomical resource for further investigation of the glymphatic function.
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Affiliation(s)
- Xu-Zhong He
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, Suzhou, PR China
| | - Xin Li
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, Suzhou, PR China
| | - Zhen-Hua Li
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, Suzhou, PR China
| | - Jing-Cai Meng
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, Suzhou, PR China
| | - Rui-Ting Mao
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, Suzhou, PR China
| | - Xue-Ke Zhang
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, Suzhou, PR China
| | - Rong-Ting Zhang
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, Suzhou, PR China
| | - Huai-Liang Huang
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, Suzhou, PR China
| | - Qian Gui
- Department of Neurology, Suzhou Municipal Hospital, Suzhou, PR China
| | - Guang-Yin Xu
- Institute of Neuroscience, Soochow University, Suzhou, PR China
| | - Lin-Hui Wang
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, Suzhou, PR China
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140
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Dysfunctional Glymphatic System with Disrupted Aquaporin 4 Expression Pattern on Astrocytes Causes Bacterial Product Accumulation in the CSF during Pneumococcal Meningitis. mBio 2022; 13:e0188622. [PMID: 36036510 PMCID: PMC9600563 DOI: 10.1128/mbio.01886-22] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Pneumococcal meningitis, inflammation of the meninges due to an infection of the Central Nervous System caused by Streptococcus pneumoniae (the pneumococcus), is the most common form of community-acquired bacterial meningitis globally. Aquaporin 4 (AQP4) water channels on astrocytic end feet regulate the solute transport of the glymphatic system, facilitating the exchange of compounds between the brain parenchyma and the cerebrospinal fluid (CSF), which is important for the clearance of waste away from the brain. Wistar rats, subjected to either pneumococcal meningitis or artificial CSF (sham control), received Evans blue-albumin (EBA) intracisternally. Overall, the meningitis group presented a significant impairment of the glymphatic system by retaining the EBA in the CSF compartments compared to the uninfected sham group. Our results clearly showed that during pneumococcal meningitis, the glymphatic system does not function because of a detachment of the astrocytic end feet from the blood-brain barrier (BBB) vascular endothelium, which leads to misplacement of AQP4 with the consequent loss of the AQP4 water channel's functionality. IMPORTANCE The lack of solute drainage due to a dysfunctional glymphatic system leads to an increase of the neurotoxic bacterial material in the CSF compartments of the brain, ultimately leading to brain-wide neuroinflammation and neuronal damage with consequent impairment of neurological functions. The loss of function of the glymphatic system can therefore be a leading cause of the neurological sequelae developing post-bacterial meningitis.
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141
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Lynch M, Pham W, Sinclair B, O’Brien TJ, Law M, Vivash L. Perivascular spaces as a potential biomarker of Alzheimer's disease. Front Neurosci 2022; 16:1021131. [PMID: 36330347 PMCID: PMC9623161 DOI: 10.3389/fnins.2022.1021131] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 09/23/2022] [Indexed: 07/20/2023] Open
Abstract
Alzheimer's disease (AD) is a highly damaging disease that affects one's cognition and memory and presents an increasing societal and economic burden globally. Considerable research has gone into understanding AD; however, there is still a lack of effective biomarkers that aid in early diagnosis and intervention. The recent discovery of the glymphatic system and associated Perivascular Spaces (PVS) has led to the theory that enlarged PVS (ePVS) may be an indicator of AD progression and act as an early diagnostic marker. Visible on Magnetic Resonance Imaging (MRI), PVS appear to enlarge when known biomarkers of AD, amyloid-β and tau, accumulate. The central goal of ePVS and AD research is to determine when ePVS occurs in AD progression and if ePVS are causal or epiphenomena. Furthermore, if ePVS are indeed causative, interventions promoting glymphatic clearance are an attractive target for research. However, it is necessary first to ascertain where on the pathological progression of AD ePVS occurs. This review aims to examine the knowledge gap that exists in understanding the contribution of ePVS to AD. It is essential to understand whether ePVS in the brain correlate with increased regional tau distribution and global or regional Amyloid-β distribution and to determine if these spaces increase proportionally over time as individuals experience neurodegeneration. This review demonstrates that ePVS are associated with reduced glymphatic clearance and that this reduced clearance is associated with an increase in amyloid-β. However, it is not yet understood if ePVS are the outcome or driver of protein accumulation. Further, it is not yet clear if ePVS volume and number change longitudinally. Ultimately, it is vital to determine early diagnostic criteria and early interventions for AD to ease the burden it presents to the world; ePVS may be able to fulfill this role and therefore merit further research.
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Affiliation(s)
- Miranda Lynch
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - William Pham
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Benjamin Sinclair
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
- Department of Neurology, Alfred Hospital, Melbourne, VIC, Australia
- Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, VIC, Australia
| | - Terence J. O’Brien
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
- Department of Neurology, Alfred Hospital, Melbourne, VIC, Australia
- Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, VIC, Australia
- Department of Neurology, Royal Melbourne Hospital, University of Melbourne, Melbourne, VIC, Australia
| | - Meng Law
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
- Department of Radiology, Alfred Health, Melbourne, VIC, Australia
- Department of Electrical and Computer Systems Engineering, Monash University, Melbourne, VIC, Australia
| | - Lucy Vivash
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia
- Department of Neurology, Alfred Hospital, Melbourne, VIC, Australia
- Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, VIC, Australia
- Department of Neurology, Royal Melbourne Hospital, University of Melbourne, Melbourne, VIC, Australia
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142
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Xu JQ, Liu QQ, Huang SY, Duan CY, Lu HB, Cao Y, Hu JZ. The lymphatic system: a therapeutic target for central nervous system disorders. Neural Regen Res 2022; 18:1249-1256. [PMID: 36453401 PMCID: PMC9838139 DOI: 10.4103/1673-5374.355741] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The lymphatic vasculature forms an organized network that covers the whole body and is involved in fluid homeostasis, metabolite clearance, and immune surveillance. The recent identification of functional lymphatic vessels in the meninges of the brain and the spinal cord has provided novel insights into neurophysiology. They emerge as major pathways for fluid exchange. The abundance of immune cells in lymphatic vessels and meninges also suggests that lymphatic vessels are actively involved in neuroimmunity. The lymphatic system, through its role in the clearance of neurotoxic proteins, autoimmune cell infiltration, and the transmission of pro-inflammatory signals, participates in the pathogenesis of a variety of neurological disorders, including neurodegenerative and neuroinflammatory diseases and traumatic injury. Vascular endothelial growth factor C is the master regulator of lymphangiogenesis, a process that is critical for the maintenance of central nervous system homeostasis. In this review, we summarize current knowledge and recent advances relating to the anatomical features and immunological functions of the lymphatic system of the central nervous system and highlight its potential as a therapeutic target for neurological disorders and central nervous system repair.
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Affiliation(s)
- Jia-Qi Xu
- Department of Spine Surgery and Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan Province, China,Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Changsha, Hunan Province, China,Mobile Health Ministry of Education - China Mobile Joint Laboratory, Changsha, Hunan Province, China,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan Province, China
| | - Qian-Qi Liu
- Department of Spine Surgery and Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan Province, China,Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Changsha, Hunan Province, China,Mobile Health Ministry of Education - China Mobile Joint Laboratory, Changsha, Hunan Province, China,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan Province, China
| | - Sheng-Yuan Huang
- Department of Cardiovascular Surgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan Province, China
| | - Chun-Yue Duan
- Department of Spine Surgery and Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan Province, China,Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Changsha, Hunan Province, China,Mobile Health Ministry of Education - China Mobile Joint Laboratory, Changsha, Hunan Province, China,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan Province, China
| | - Hong-Bin Lu
- Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Changsha, Hunan Province, China,Mobile Health Ministry of Education - China Mobile Joint Laboratory, Changsha, Hunan Province, China,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan Province, China,Department of Sports Medicine, Xiangya Hospital, Central South University, Changsha, Hunan Province, China,Correspondence to: Yong Cao, or ; Hong-Bin Lu, ; Jian-Zhong Hu, .
| | - Yong Cao
- Department of Spine Surgery and Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan Province, China,Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Changsha, Hunan Province, China,Mobile Health Ministry of Education - China Mobile Joint Laboratory, Changsha, Hunan Province, China,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan Province, China,Correspondence to: Yong Cao, or ; Hong-Bin Lu, ; Jian-Zhong Hu, .
| | - Jian-Zhong Hu
- Department of Spine Surgery and Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan Province, China,Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Changsha, Hunan Province, China,Mobile Health Ministry of Education - China Mobile Joint Laboratory, Changsha, Hunan Province, China,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan Province, China,Correspondence to: Yong Cao, or ; Hong-Bin Lu, ; Jian-Zhong Hu, .
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143
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Arighi A, Arcaro M, Fumagalli GG, Carandini T, Pietroboni AM, Sacchi L, Fenoglio C, Serpente M, Sorrentino F, Isgrò G, Turkheimer F, Scarpini E, Galimberti D. Aquaporin-4 cerebrospinal fluid levels are higher in neurodegenerative dementia: looking at glymphatic system dysregulation. Alzheimers Res Ther 2022; 14:135. [PMID: 36115967 PMCID: PMC9482276 DOI: 10.1186/s13195-022-01077-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 09/04/2022] [Indexed: 01/15/2023]
Abstract
Aquaporin-4 (AQP4) is a channel protein that plays a fundamental role in glymphatic system, a newly described pathway for fluid exchange in the central nervous system, as well as a central figure in a fascinating new theory for the pathophysiology of neurodegenerative diseases such as Alzheimer’s disease (AD) and frontotemporal dementia (FTD). In this study, cerebrospinal fluid (CSF) concentration of AQP4, amyloid-β, total tau and P-tau were determined in 103 CSF samples from patients affected by neurodegenerative dementias (AD and FTD) or psychiatric diseases and 21 controls. Significantly higher levels of AQP4 were found in AD and FTD patients compared to subjects not affected by neurodegenerative diseases, and a significant, positive correlation between AQP4 and total tau levels was found. This evidence may pave the way for future studies focused on the role of this channel protein in the clinical assessment of the glymphatic function and degree of neurodegeneration.
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144
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The Role of Glymphatic System in Alzheimer’s and Parkinson’s Disease Pathogenesis. Biomedicines 2022; 10:biomedicines10092261. [PMID: 36140362 PMCID: PMC9496080 DOI: 10.3390/biomedicines10092261] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/07/2022] [Accepted: 09/08/2022] [Indexed: 11/30/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common cause of neurodegenerative dementia, whilst Parkinson’s disease (PD) is a neurodegenerative movement disorder. These two neurodegenerative disorders share the accumulation of toxic proteins as a pathological hallmark. The lack of definitive disease-modifying treatments for these neurogenerative diseases has led to the hypothesis of new pathogenic mechanisms to target and design new potential therapeutic approaches. The recent observation that the glymphatic system is supposed to be responsible for the movement of cerebrospinal fluid into the brain and clearance of metabolic waste has led to study its involvement in the pathogenesis of these classic proteinopathies. Aquaporin-4 (AQP4), a water channel located in the endfeet of astrocyte membrane, is considered a primary driver of the glymphatic clearance system, and defective AQP4-mediated glymphatic drainage has been linked to proteinopathies. The objective of the present review is to present the recent body of knowledge that links the glymphatic system to the pathogenesis of AD and PD disease and other lifestyle factors such as sleep deprivation and exercise that may influence glymphatic system function. We will also focus on the potential neuroimaging approaches that could identify a neuroimaging marker to detect glymphatic system changes.
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145
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Ocular Lymphatic and Glymphatic Systems: Implications for Retinal Health and Disease. Int J Mol Sci 2022; 23:ijms231710139. [PMID: 36077535 PMCID: PMC9456449 DOI: 10.3390/ijms231710139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 09/01/2022] [Accepted: 09/02/2022] [Indexed: 11/17/2022] Open
Abstract
Clearance of ocular fluid and metabolic waste is a critical function of the eye in health and disease. The eye has distinct fluid outflow pathways in both the anterior and posterior segments. Although the anterior outflow pathway is well characterized, little is known about posterior outflow routes. Recent studies suggest that lymphatic and glymphatic systems play an important role in the clearance of fluid and waste products from the posterior segment of the eye. The lymphatic system is a vascular network that runs parallel to the blood circulatory system. It plays an essential role in maintenance of fluid homeostasis and immune surveillance in the body. Recent studies have reported lymphatics in the cornea (under pathological conditions), ciliary body, choroid, and optic nerve meninges. The evidence of lymphatics in optic nerve meninges is, however, limited. An alternative lymphatic system termed the glymphatic system was recently discovered in the rodent eye and brain. This system is a glial cell-based perivascular network responsible for the clearance of interstitial fluid and metabolic waste. In this review, we will discuss our current knowledge of ocular lymphatic and glymphatic systems and their role in retinal degenerative diseases.
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146
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The glymphatic system: implications for drugs for central nervous system diseases. Nat Rev Drug Discov 2022; 21:763-779. [PMID: 35948785 DOI: 10.1038/s41573-022-00500-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/22/2022] [Indexed: 12/14/2022]
Abstract
In the past decade, evidence for a fluid clearance pathway in the central nervous system known as the glymphatic system has grown. According to the glymphatic system concept, cerebrospinal fluid flows directionally through the brain and non-selectively clears the interstitium of metabolic waste. Importantly, the glymphatic system may be modulated by particular drugs such as anaesthetics, as well as by non-pharmacological factors such as sleep, and its dysfunction has been implicated in central nervous system disorders such as Alzheimer disease. Although the glymphatic system is best described in rodents, reports using multiple neuroimaging modalities indicate that a similar transport system exists in the human brain. Here, we overview the evidence for the glymphatic system and its role in disease and discuss opportunities to harness the glymphatic system therapeutically; for example, by improving the effectiveness of intrathecally delivered drugs.
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147
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Li G, Cao Y, Tang X, Huang J, Cai L, Zhou L. The meningeal lymphatic vessels and the glymphatic system: Potential therapeutic targets in neurological disorders. J Cereb Blood Flow Metab 2022; 42:1364-1382. [PMID: 35484910 PMCID: PMC9274866 DOI: 10.1177/0271678x221098145] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 04/03/2022] [Accepted: 04/14/2022] [Indexed: 02/05/2023]
Abstract
The recent discovery of the meningeal lymphatic vessels (mLVs) and glymphatic pathways has challenged the long-lasting dogma that the central nervous system (CNS) lacks a lymphatic system and therefore does not interact with peripheral immunity. This discovery has reshaped our understanding of mechanisms underlying CNS drainage. Under normal conditions, a close connection between mLVs and the glymphatic system enables metabolic waste removal, immune cell trafficking, and CNS immune surveillance. Dysfunction of the glymphatic-mLV system can lead to toxic protein accumulation in the brain, and it contributes to the development of a series of neurodegenerative disorders, such as Alzheimer's and Parkinson's diseases. The identification of precise cerebral transport routes is based mainly on indirect, invasive imaging of animals, and the results cannot always be applied to humans. Here we review the functions of the glymphatic-mLV system and evidence for its involvement in some CNS diseases. We focus on emerging noninvasive imaging techniques to evaluate the human glymphatic-mLV system and their potential for preclinical diagnosis and prevention of neurodegenerative diseases. Potential strategies that target the glymphatic-mLV system in order to treat and prevent neurological disorders are also discussed.
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Affiliation(s)
- Gaowei Li
- Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, China
| | - Yi Cao
- Department of Neurosurgery, Chengdu Second People's hospital, Chengdu, China
| | - Xin Tang
- Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, China
| | - Jianhan Huang
- Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, China
| | - Linjun Cai
- Department of Neurology, West China Hospital, Sichuan University, Chengdu, China
| | - Liangxue Zhou
- Department of Neurosurgery, West China Hospital, Sichuan University, Chengdu, China
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148
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Moro C, Valverde A, Dole M, Hoh Kam J, Hamilton C, Liebert A, Bicknell B, Benabid AL, Magistretti P, Mitrofanis J. The effect of photobiomodulation on the brain during wakefulness and sleep. Front Neurosci 2022; 16:942536. [PMID: 35968381 PMCID: PMC9366035 DOI: 10.3389/fnins.2022.942536] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 07/08/2022] [Indexed: 11/26/2022] Open
Abstract
Over the last seventy years or so, many previous studies have shown that photobiomodulation, the use of red to near infrared light on body tissues, can improve central and peripheral neuronal function and survival in both health and in disease. These improvements are thought to arise principally from an impact of photobiomodulation on mitochondrial and non-mitochondrial mechanisms in a range of different cell types, including neurones. This impact has downstream effects on many stimulatory and protective genes. An often-neglected feature of nearly all of these improvements is that they have been induced during the state of wakefulness. Recent studies have shown that when applied during the state of sleep, photobiomodulation can also be of benefit, but in a different way, by improving the flow of cerebrospinal fluid and the clearance of toxic waste-products from the brain. In this review, we consider the potential differential effects of photobiomodulation dependent on the state of arousal. We speculate that the effects of photobiomodulation is on different cells and systems depending on whether it is applied during wakefulness or sleep, that it may follow a circadian rhythm. We speculate further that the arousal-dependent photobiomodulation effects are mediated principally through a biophoton – ultra-weak light emission – network of communication and repair across the brain.
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Affiliation(s)
- Cecile Moro
- FDD and CEA-LETI, Clinatec, Université Grenoble Alpes, Grenoble, France
| | - Audrey Valverde
- FDD and CEA-LETI, Clinatec, Université Grenoble Alpes, Grenoble, France
| | - Marjorie Dole
- FDD and CEA-LETI, Clinatec, Université Grenoble Alpes, Grenoble, France
| | - Jaimie Hoh Kam
- FDD and CEA-LETI, Clinatec, Université Grenoble Alpes, Grenoble, France
| | | | - Ann Liebert
- Governance and Research Department, Sydney Adventist Hospital, Sydney, NSW, Australia
| | - Brian Bicknell
- Faculty of Health Sciences, Australian Catholic University, Sydney, NSW, Australia
| | | | - Pierre Magistretti
- FDD and CEA-LETI, Clinatec, Université Grenoble Alpes, Grenoble, France
- Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - John Mitrofanis
- FDD and CEA-LETI, Clinatec, Université Grenoble Alpes, Grenoble, France
- Institute of Ophthalmology, University College London, London, United Kingdom
- *Correspondence: John Mitrofanis,
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149
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Wang FX, Xu CL, Su C, Li J, Lin JY. β-Hydroxybutyrate Attenuates Painful Diabetic Neuropathy via Restoration of the Aquaporin-4 Polarity in the Spinal Glymphatic System. Front Neurosci 2022; 16:926128. [PMID: 35898407 PMCID: PMC9309893 DOI: 10.3389/fnins.2022.926128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 06/10/2022] [Indexed: 11/13/2022] Open
Abstract
Waste removal is essential for maintaining homeostasis and the normal function of the central nervous system (CNS). The glymphatic system based on aquaporin-4 (AQP4) water channels on the endfeet of astrocytes is recently discovered as the excretion pathway for metabolic waste products of CNS. In the CNS, α-syntrophin (SNTA1) directly or indirectly anchors AQP4 in astrocyte membranes facing blood vessels. Studies have indicated that β-hydroxybutyrate (BHB) can raise the expression of SNTA1 and thus restoring AQP4 polarity in mice models with Alzheimer’s disease. The study aims to evaluate the neuroprotective mechanism of BHB in rats with painful diabetic neuropathy (PDN). PDN rats were modeled under a high-fat and high-glucose diet with a low dose of streptozotocin. Magnetic resonance imaging (MRI) was applied to observe the clearance of contrast to indicate the functional variability of the spinal glymphatic system. Mechanical allodynia was assessed by paw withdrawal threshold. The expressions of SNTA1 and AQP4 were tested, and the polarity reversal of AQP4 protein was measured. As demonstrated, PDN rats were manifested with deceased contrast clearance of the spinal glymphatic system, enhanced mechanical allodynia, lower expression of SNTA1, higher expression of AQP4, and reversed polarity of AQP4 protein. An opposite change in the above characteristics was observed in rats being treated with BHB. This is the first study that demonstrated the neuroprotective mechanism of BHB to attenuate PDN via restoration of the AQP4 polarity in the spinal glymphatic system and provides a promising therapeutic strategy for PDN.
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Affiliation(s)
- Fei-xiang Wang
- Department of Anesthesiology, The Affiliated Hospital of North Sichuan Medical College, Nanchong, China
| | - Chi-liang Xu
- Department of Anesthesiology, The Affiliated Hospital of North Sichuan Medical College, Nanchong, China
| | - Can Su
- Department of Medical Imaging, The Affiliated Hospital of North Sichuan Medical College, Nanchong, China
| | - Jiang Li
- Department of Anesthesiology, The Affiliated Hospital of North Sichuan Medical College, Nanchong, China
| | - Jing-yan Lin
- Department of Anesthesiology, The Affiliated Hospital of North Sichuan Medical College, Nanchong, China
- *Correspondence: Jing-yan Lin,
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Wang GQ, Wang FX, He YN, Lin JY. Plasticity of the spinal glymphatic system in male SD rats with painful diabetic neuropathy induced by type 2 diabetes mellitus. J Neurosci Res 2022; 100:1908-1920. [PMID: 35796387 PMCID: PMC9541551 DOI: 10.1002/jnr.25104] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 06/06/2022] [Accepted: 06/22/2022] [Indexed: 11/08/2022]
Abstract
The glymphatic system is a recently discovered glial‐dependent macroscopic interstitial waste clearance system that promotes the efficient elimination of soluble proteins and metabolites from the central nervous system. Its anatomic foundation is the astrocytes and aquaporin‐4 (AQP4) water channels on the endfeet of astrocytes. The aim of this study is to evaluate the plasticity of the spinal glymphatic system in male SD rats with painful diabetic neuropathy (PDN) induced by type 2 diabetes mellitus. PDN rats were modeled under a high‐fat and high‐glucose diet with a low dose of streptozotocin. MRI was applied to observe the infiltration and clearance of contrast to indicate the functional variability of the glymphatic system at the spinal cord level. The paw withdrawal threshold was used to represent mechanical allodynia. The numerical change of glial fibrillary acidic protein (GFAP) positive astrocytes was assessed and the polarity reversal of AQP4 protein was measured by immunofluorescence. As a result, deceased contrast infiltration and clearance, enhanced mechanical allodynia, increased number of GFAP positive astrocytes, and reversed polarity of AQP4 protein were found in the PDN rats. The above molecular level changes may contribute to the impairment of the spinal glymphatic system in PDN rats. This study revealed the molecular and functional variations of the spinal glymphatic system in PDN rats and for the first time indicated that there might be a correlation between the impaired spinal glymphatic system and PDN rats.
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Affiliation(s)
- Guo-Qiang Wang
- Department of Anesthesiology, the Affiliated Hospital of North Sichuan Medical College, Nanchong, China.,Department of Pain Treatment, Physical and Mental Hospital of Nanchong City, Nanchong, China
| | - Fei-Xiang Wang
- Department of Anesthesiology, the Affiliated Hospital of North Sichuan Medical College, Nanchong, China
| | - Yi-Na He
- Department of Anesthesiology, Nanchong Central Hospital, Nanchong, China
| | - Jing-Yan Lin
- Department of Anesthesiology, the Affiliated Hospital of North Sichuan Medical College, Nanchong, China
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