1
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Paez-Gonzalez P, Lopez-de-San-Sebastian J, Ceron-Funez R, Jimenez AJ, Rodríguez-Perez LM. Therapeutic strategies to recover ependymal barrier after inflammatory damage: relevance for recovering neurogenesis during development. Front Neurosci 2023; 17:1204197. [PMID: 37397456 PMCID: PMC10308384 DOI: 10.3389/fnins.2023.1204197] [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: 04/11/2023] [Accepted: 05/22/2023] [Indexed: 07/04/2023] Open
Abstract
The epithelium covering the surfaces of the cerebral ventricular system is known as the ependyma, and is essential for maintaining the physical and functional integrity of the central nervous system. Additionally, the ependyma plays an essential role in neurogenesis, neuroinflammatory modulation and neurodegenerative diseases. Ependyma barrier is severely affected by perinatal hemorrhages and infections that cross the blood brain barrier. The recovery and regeneration of ependyma after damage are key to stabilizing neuroinflammatory and neurodegenerative processes that are critical during early postnatal ages. Unfortunately, there are no effective therapies to regenerate this tissue in human patients. Here, the roles of the ependymal barrier in the context of neurogenesis and homeostasis are reviewed, and future research lines for development of actual therapeutic strategies are discussed.
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Affiliation(s)
- Patricia Paez-Gonzalez
- Department of Cell Biology, Genetics and Physiology, University of Malaga, Málaga, Spain
- Instituto de Investigación Biomédica de Málaga y Plataforma en Nanomedicina-IBIMA Plataforma BIONAND, Málaga, Spain
| | | | - Raquel Ceron-Funez
- Department of Cell Biology, Genetics and Physiology, University of Malaga, Málaga, Spain
| | - Antonio J. Jimenez
- Instituto de Investigación Biomédica de Málaga y Plataforma en Nanomedicina-IBIMA Plataforma BIONAND, Málaga, Spain
| | - Luis Manuel Rodríguez-Perez
- Department of Cell Biology, Genetics and Physiology, University of Malaga, Málaga, Spain
- Instituto de Investigación Biomédica de Málaga y Plataforma en Nanomedicina-IBIMA Plataforma BIONAND, Málaga, Spain
- Department of Human Physiology, Human Histology, Pathological Anatomy and Sports, University of Malaga, Málaga, Spain
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2
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Altered Expression of AQP1 and AQP4 in Brain Barriers and Cerebrospinal Fluid May Affect Cerebral Water Balance during Chronic Hypertension. Int J Mol Sci 2022; 23:ijms232012277. [PMID: 36293145 PMCID: PMC9603298 DOI: 10.3390/ijms232012277] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 10/03/2022] [Accepted: 10/11/2022] [Indexed: 11/07/2022] Open
Abstract
Hypertension is the leading cause of cardiovascular affection and premature death worldwide. The spontaneously hypertensive rat (SHR) is the most common animal model of hypertension, which is characterized by secondary ventricular dilation and hydrocephalus. Aquaporin (AQP) 1 and 4 are the main water channels responsible for the brain’s water balance. The present study focuses on defining the expression of AQPs through the time course of the development of spontaneous chronic hypertension. We performed immunofluorescence and ELISA to examine brain AQPs from 10 SHR, and 10 Wistar−Kyoto (WKY) rats studied at 6 and 12 months old. There was a significant decrease in AQP1 in the choroid plexus of the SHR-12-months group compared with the age-matched control (p < 0.05). In the ependyma, AQP4 was significantly decreased only in the SHR-12-months group compared with the control or SHR-6-months groups (p < 0.05). Per contra, AQP4 increased in astrocytes end-feet of 6 months and 12 months SHR rats (p < 0.05). CSF AQP detection was higher in the SHR-12-months group than in the age-matched control group. CSF findings were confirmed by Western blot. In SHR, ependymal and choroidal AQPs decreased over time, while CSF AQPs levels increased. In turn, astrocytes AQP4 increased in SHR rats. These AQP alterations may underlie hypertensive-dependent ventriculomegaly.
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3
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Yang Y, Wang C, Chen R, Wang Y, Tan C, Liu J, Zhang Q, Xiao G. Novel therapeutic modulators of astrocytes for hydrocephalus. Front Mol Neurosci 2022; 15:932955. [PMID: 36226316 PMCID: PMC9549203 DOI: 10.3389/fnmol.2022.932955] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 09/06/2022] [Indexed: 11/23/2022] Open
Abstract
Hydrocephalus is mainly characterized by excessive production or impaired absorption of cerebrospinal fluid that causes ventricular dilation and intracranial hypertension. Astrocytes are the key response cells to inflammation in the central nervous system. In hydrocephalus, astrocytes are activated and show dual characteristics depending on the period of development of the disease. They can suppress the disease in the early stage and may aggravate it in the late stage. More evidence suggests that therapeutics targeting astrocytes may be promising for hydrocephalus. In this review, based on previous studies, we summarize different forms of hydrocephalus-induced astrocyte reactivity and the corresponding function of these responses in hydrocephalus. We also discuss the therapeutic effects of astrocyte regulation on hydrocephalus in experimental studies.
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Affiliation(s)
- Yijian Yang
- Department of Neurosurgery, Affiliated Nanhua Hospital, Hengyang Medical School, University of South China, Hengyang, China
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Diagnosis and Treatment Center for Hydrocephalus, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Chuansen Wang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Diagnosis and Treatment Center for Hydrocephalus, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Rui Chen
- Department of Neurosurgery, Affiliated Nanhua Hospital, Hengyang Medical School, University of South China, Hengyang, China
| | - Yuchang Wang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Diagnosis and Treatment Center for Hydrocephalus, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Changwu Tan
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Diagnosis and Treatment Center for Hydrocephalus, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Jingping Liu
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Diagnosis and Treatment Center for Hydrocephalus, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Qinghua Zhang
- Department of Neurosurgery, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen, China
- The 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, China
- *Correspondence: Qinghua Zhang,
| | - Gelei Xiao
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Diagnosis and Treatment Center for Hydrocephalus, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- Gelei Xiao,
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4
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Zhao Z, He J, Chen Y, Wang Y, Wang C, Tan C, Liao J, Xiao G. The pathogenesis of idiopathic normal pressure hydrocephalus based on the understanding of AQP1 and AQP4. Front Mol Neurosci 2022; 15:952036. [PMID: 36204139 PMCID: PMC9530743 DOI: 10.3389/fnmol.2022.952036] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 08/12/2022] [Indexed: 11/21/2022] Open
Abstract
Idiopathic normal pressure hydrocephalus (iNPH) is a neurological disorder without a recognized cause. Aquaporins (AQPs) are transmembrane channels that carry water through cell membranes and are critical for cerebrospinal fluid circulation and cerebral water balance. The function of AQPs in developing and maintaining hydrocephalus should be studied in greater detail as a possible diagnostic and therapeutic tool. Recent research indicates that patients with iNPH exhibited high levels of aquaporin 1 and low levels of aquaporin 4 expression, suggesting that these AQPs are essential in iNPH pathogenesis. To determine the source of iNPH and diagnose and treat it, it is necessary to examine and appreciate their function in the genesis and maintenance of hydrocephalus. The expression, function, and regulation of AQPs in iNPH are reviewed in this article, in order to provide fresh targets and suggestions for future research.
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Affiliation(s)
- Zitong Zhao
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Diagnosis and Treatment Center for Hydrocephalus, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Jian He
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha, China
| | - Yibing Chen
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Diagnosis and Treatment Center for Hydrocephalus, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Yuchang Wang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Diagnosis and Treatment Center for Hydrocephalus, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Chuansen Wang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Diagnosis and Treatment Center for Hydrocephalus, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Changwu Tan
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Diagnosis and Treatment Center for Hydrocephalus, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Junbo Liao
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Diagnosis and Treatment Center for Hydrocephalus, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Gelei Xiao
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- Diagnosis and Treatment Center for Hydrocephalus, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
- *Correspondence: Gelei Xiao
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5
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Cellular Distribution of Brain Aquaporins and Their Contribution to Cerebrospinal Fluid Homeostasis and Hydrocephalus. Biomolecules 2022; 12:biom12040530. [PMID: 35454119 PMCID: PMC9025855 DOI: 10.3390/biom12040530] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 03/28/2022] [Accepted: 03/30/2022] [Indexed: 01/19/2023] Open
Abstract
Brain aquaporins facilitate the movement of water between the four water compartments: blood, cerebrospinal fluid, interstitial fluid, and intracellular fluid. This work analyzes the expression of the four most abundant aquaporins (AQPs) (AQP1, AQP4, AQP9, and AQP11) in the brains of mice and discuss their contribution to hydrocephalus. We analyzed available data from single-cell RNA sequencing of the central nervous system of mice to describe the expression of aquaporins and compare their distribution with that based on qPCR, western blot, and immunohistochemistry assays. Expression of AQP1 in the apical cell membrane of choroid plexus epithelial cells and of AQP4 in ependymal cells, glia limitans, and astrocyte processes in the pericapillary end foot is consistent with the involvement of both proteins in cerebrospinal fluid homeostasis. The expression of both aquaporins compensates for experimentally induced hydrocephalus in the animals. Recent data demonstrate that hypoxia in aged animals alters AQP4 expression in the choroidal plexus and cortex, increasing the ventricle size and intraventricular pressure. Cerebral distensibility is reduced in parallel with a reduction in cerebrospinal fluid drainage and cognitive deterioration. We propose that aged mice chronically exposed to hypoxia represent an excellent experimental model for studying the pathophysiological characteristics of idiopathic normal pressure hydrocephalus and roles for AQPs in such disease.
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6
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Wagner K, Unger L, Salman MM, Kitchen P, Bill RM, Yool AJ. Signaling Mechanisms and Pharmacological Modulators Governing Diverse Aquaporin Functions in Human Health and Disease. Int J Mol Sci 2022; 23:1388. [PMID: 35163313 PMCID: PMC8836214 DOI: 10.3390/ijms23031388] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/18/2022] [Accepted: 01/20/2022] [Indexed: 02/07/2023] Open
Abstract
The aquaporins (AQPs) are a family of small integral membrane proteins that facilitate the bidirectional transport of water across biological membranes in response to osmotic pressure gradients as well as enable the transmembrane diffusion of small neutral solutes (such as urea, glycerol, and hydrogen peroxide) and ions. AQPs are expressed throughout the human body. Here, we review their key roles in fluid homeostasis, glandular secretions, signal transduction and sensation, barrier function, immunity and inflammation, cell migration, and angiogenesis. Evidence from a wide variety of studies now supports a view of the functions of AQPs being much more complex than simply mediating the passive flow of water across biological membranes. The discovery and development of small-molecule AQP inhibitors for research use and therapeutic development will lead to new insights into the basic biology of and novel treatments for the wide range of AQP-associated disorders.
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Affiliation(s)
- Kim Wagner
- School of Biomedicine, University of Adelaide, Adelaide, SA 5005, Australia;
| | - Lucas Unger
- College of Health and Life Sciences, Aston University, Birmingham B4 7ET, UK; (L.U.); (P.K.)
| | - Mootaz M. Salman
- Department of Physiology Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK;
- Oxford Parkinson’s Disease Centre, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - Philip Kitchen
- College of Health and Life Sciences, Aston University, Birmingham B4 7ET, UK; (L.U.); (P.K.)
| | - Roslyn M. Bill
- College of Health and Life Sciences, Aston University, Birmingham B4 7ET, UK; (L.U.); (P.K.)
| | - Andrea J. Yool
- School of Biomedicine, University of Adelaide, Adelaide, SA 5005, Australia;
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7
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Kondoh D, Nakamura T, Tsuji E, Hosotani M, Ichii O, Irie T, Mishima T, Nagasaki KI, Kon Y. Cotton rats (Sigmodon hispidus) with a high prevalence of hydrocephalus without clinical symptoms. Neuropathology 2021; 42:16-27. [PMID: 34957592 DOI: 10.1111/neup.12776] [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: 04/14/2021] [Revised: 08/10/2021] [Accepted: 08/10/2021] [Indexed: 12/01/2022]
Abstract
Normal-pressure hydrocephalus (NPH) is a condition in which the ventricle is enlarged without elevated cerebrospinal fluid pressure, and it generally develops in later life and progresses slowly. A complete animal model that mimics human idiopathic NPH has not yet been established, and the onset mechanisms and detailed pathomechanisms of NPH are not fully understood. Here, we demonstrate a high spontaneous prevalence (34.6%) of hydrocephalus without clinical symptoms in inbred cotton rats (Sigmodon hispidus). In all 46 hydrocephalic cotton rats, the severity was mild or moderate and not severe. The dilation was limited to the lateral ventricles, and none of the hemorrhage, ventriculitis, meningitis, or tumor formation was found in hydrocephalic cotton rats. These findings indicate that the type of hydrocephalus in cotton rats is similar to that of communicating idiopathic NPH. Histopathological examinations revealed that the inner granular and pyramidal layers (layers IV and V) of the neocortex became thinner in hydrocephalic brains. A small number of pyramidal cells were positive for Fluoro-Jade C (a degenerating neuron marker) and ionized calcium-binding adaptor molecule 1 (Iba1)-immunoreactive microglia were in contact with the degenerating neurons in the hydrocephalic neocortex, suggesting that hydrocephalic cotton rats are more or less impaired projections from the neocortex. This study highlights cotton rats as a candidate for novel models to elucidate the pathomechanism of idiopathic NPH. Additionally, cotton rats have some noticeable systemic pathological phenotypes, such as chronic kidney disease and metabolic disorders. Thus, this model might also be useful for researching the comorbidities of NPH to other diseases.
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Affiliation(s)
- Daisuke Kondoh
- Laboratory of Veterinary Anatomy, Department of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan
| | - Teppei Nakamura
- Laboratory of Anatomy, Department of Basic Veterinary Science, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan.,Department of Biological Safety Research, Chitose Laboratory, Japan Food Research Laboratories, Chitose, Japan
| | - Erika Tsuji
- Department of Biological Safety Research, Chitose Laboratory, Japan Food Research Laboratories, Chitose, Japan
| | - Marina Hosotani
- Laboratory of Veterinary Anatomy, Department of Veterinary Medicine, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan
| | - Osamu Ichii
- Laboratory of Anatomy, Department of Basic Veterinary Science, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan.,Laboratory of Agrobiomedical Science, Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Takao Irie
- Medical Zoology Group, Department of Infectious Diseases, Hokkaido Institute of Public Health, Sapporo, Japan.,Laboratory of Veterinary Parasitic Diseases, Department of Veterinary Sciences, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan
| | - Takashi Mishima
- Department of Biological Safety Research, Chitose Laboratory, Japan Food Research Laboratories, Chitose, Japan
| | - Ken-Ichi Nagasaki
- Department of Biological Safety Research, Tama Laboratory, Japan Food Research Laboratories, Tama, Japan
| | - Yasuhiro Kon
- Laboratory of Anatomy, Department of Basic Veterinary Science, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
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8
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Urushihata T, Takuwa H, Takahashi M, Kershaw J, Tachibana Y, Nitta N, Shibata S, Yasui M, Higuchi M, Obata T. Exploring cell membrane water exchange in aquaporin-4-deficient ischemic mouse brain using diffusion-weighted MRI. Eur Radiol Exp 2021; 5:44. [PMID: 34617156 PMCID: PMC8494869 DOI: 10.1186/s41747-021-00244-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 08/27/2021] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Aquaporin-4 is a membrane channel protein that is highly expressed in brain astrocytes and facilitates the transport of water molecules. It has been suggested that suppression of aquaporin-4 function may be an effective treatment for reducing cellular edema after cerebral infarction. It is therefore important to develop clinically applicable measurement systems to evaluate and better understand the effects of aquaporin-4 suppression on the living body. METHODS Animal models of focal cerebral ischemia were created by surgically occluding the middle cerebral artery of wild-type and aquaporin-4 knockout mice, after which multi-b-value multi-diffusion-time diffusion-weighted imaging measurements were performed. Data were analyzed with both the apparent diffusion coefficient (ADC) model and a compartmental water-exchange model. RESULTS ADCs were estimated for five different b value ranges. The ADC of aquaporin-4 knockout mice in the contralateral region was significantly higher than that of wild-type mice for each range. In contrast, aquaporin-4 knockout mice had significantly lower ADC than wild-type mice in ischemic tissue for each b-value range. Genotype-dependent differences in the ADC were particularly significant for the lowest ranges in normal tissue and for the highest ranges in ischemic tissue. The ADCs measured at different diffusion times were significantly different for both genotypes. Fitting of the water-exchange model to the ischemic region data found that the water-exchange time in aquaporin-4 knockout mice was approximately 2.5 times longer than that in wild-type mice. CONCLUSIONS Multi-b-value multi-diffusion-time diffusion-weighted imaging may be useful for in vivo research and clinical diagnosis of aquaporin-4-related diseases.
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Affiliation(s)
- Takuya Urushihata
- Department of Functional Brain Imaging Research, Institute for Quantum Medical Science, QST, Chiba, 263-8555, Japan
| | - Hiroyuki Takuwa
- Department of Functional Brain Imaging Research, Institute for Quantum Medical Science, QST, Chiba, 263-8555, Japan
| | - Manami Takahashi
- Department of Functional Brain Imaging Research, Institute for Quantum Medical Science, QST, Chiba, 263-8555, Japan
| | - Jeff Kershaw
- Applied MRI Research, Department of Molecular Imaging and Theranostics, Institute for Quantum Medical Science, QST, Chiba, 263-8555, Japan
| | - Yasuhiko Tachibana
- Applied MRI Research, Department of Molecular Imaging and Theranostics, Institute for Quantum Medical Science, QST, Chiba, 263-8555, Japan
| | - Nobuhiro Nitta
- Applied MRI Research, Department of Molecular Imaging and Theranostics, Institute for Quantum Medical Science, QST, Chiba, 263-8555, Japan
| | - Sayaka Shibata
- Applied MRI Research, Department of Molecular Imaging and Theranostics, Institute for Quantum Medical Science, QST, Chiba, 263-8555, Japan
| | - Masato Yasui
- Keio Advanced Research Center for Water Biology and Medicine, Keio University, Tokyo, 160-0016, Japan
| | - Makoto Higuchi
- Department of Functional Brain Imaging Research, Institute for Quantum Medical Science, QST, Chiba, 263-8555, Japan
| | - Takayuki Obata
- Applied MRI Research, Department of Molecular Imaging and Theranostics, Institute for Quantum Medical Science, QST, Chiba, 263-8555, Japan.
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9
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Abstract
Optic nerve health is essential for proper function of the visual system. However, the pathophysiology of certain neurodegenerative disease processes affecting the optic nerve, such as glaucoma, is not fully understood. Recently, it was hypothesized that a lack of proper clearance of neurotoxins contributes to neurodegenerative diseases. The ability to clear metabolic waste is essential for tissue homeostasis in mammals, including humans. While the brain lacks the traditional lymphatic drainage system identified in other anatomical regions, there is growing evidence of a glymphatic system in the central nervous system, which structurally includes the optic nerve. Named to acknowledge the supportive role of astroglial cells, this perivascular fluid drainage system is essential to remove toxic metabolites from the central nervous system. Herein, we review existing literature describing the physiology and dysfunction of the glymphatic system specifically as it relates to the optic nerve. We summarize key imaging studies demonstrating the existence of a glymphatic system in the optic nerves of wild-type rodents, aquaporin 4-null rodents, and humans; glymphatic imaging studies in diseases where the optic nerve is impaired; and current evidence regarding pharmacological and lifestyle interventions that may help promote glymphatic function to improve optic nerve health. We conclude by highlighting future research directions that could be applied to improve imaging detection and guide therapeutic interventions for diseases affecting the optic nerve.
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Affiliation(s)
- Anisha Kasi
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA
| | - Crystal Liu
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA
| | - Muneeb A Faiq
- Department of Ophthalmology, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, NY, USA
| | - Kevin C Chan
- Department of Ophthalmology; Department of Radiology; Neuroscience Institute, NYU Grossman School of Medicine, NYU Langone Health; Center for Neural Science, College of Arts and Science, New York University, New York, NY, USA
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10
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Trillo-Contreras JL, Toledo-Aral JJ, Villadiego J, Echevarría M. Aquaporin-4 Mediates Permanent Brain Alterations in a Mouse Model of Hypoxia-Aged Hydrocephalus. Int J Mol Sci 2021; 22:ijms22189745. [PMID: 34575909 PMCID: PMC8471142 DOI: 10.3390/ijms22189745] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/06/2021] [Accepted: 09/07/2021] [Indexed: 11/29/2022] Open
Abstract
Aquaporin-4 (AQP4) is the principal water channel in the brain being expressed in astrocytes and ependymal cells. AQP4 plays an important role in cerebrospinal fluid (CSF) homeostasis, and alterations in its expression have been associated with hydrocephalus. AQP4 contributes to the development of hydrocephalus by hypoxia in aged mice, reproducing such principal characteristics of the disease. Here, we explore whether these alterations associated with the hydrocephalic state are permanent or can be reverted by reexposure to normoxia. Alterations such as ventriculomegaly, elevated intracranial pressure, and cognitive deficits were reversed, whereas deficits in CSF outflow and ventricular distensibility were not recovered, remaining impaired even one month after reestablishment of normoxia. Interestingly, in AQP4−/− mice, the impairment in CSF drainage and ventricular distensibility was completely reverted by re-normoxia, indicating that AQP4 has a structural role in the chronification of those alterations. Finally, we show that aged mice subjected to two hypoxic episodes experience permanent ventriculomegaly. These data reveal that repetitive hypoxic events in aged cerebral tissue promote the permanent alterations involved in hydrocephalic pathophysiology, which are dependent on AQP4 expression.
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Affiliation(s)
- José Luis Trillo-Contreras
- Institute of Biomedicine of Seville-IBiS, University Hospital Virgen del Rocío, CSIC, University of Seville, 41013 Seville, Spain; (J.L.T.-C.); (J.J.T.-A.)
- Department of Medical Physiology and Biophysics, University of Seville, 41009 Seville, Spain
| | - Juan José Toledo-Aral
- Institute of Biomedicine of Seville-IBiS, University Hospital Virgen del Rocío, CSIC, University of Seville, 41013 Seville, Spain; (J.L.T.-C.); (J.J.T.-A.)
- Department of Medical Physiology and Biophysics, University of Seville, 41009 Seville, Spain
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), 28031 Madrid, Spain
| | - Javier Villadiego
- Institute of Biomedicine of Seville-IBiS, University Hospital Virgen del Rocío, CSIC, University of Seville, 41013 Seville, Spain; (J.L.T.-C.); (J.J.T.-A.)
- Department of Medical Physiology and Biophysics, University of Seville, 41009 Seville, Spain
- Network Center for Biomedical Research in Neurodegenerative Diseases (CIBERNED), 28031 Madrid, Spain
- Correspondence: (J.V.); (M.E.); Tel.: +34-955-920-034 (J.V.); +34-955-920-036 (M.E.)
| | - Miriam Echevarría
- Institute of Biomedicine of Seville-IBiS, University Hospital Virgen del Rocío, CSIC, University of Seville, 41013 Seville, Spain; (J.L.T.-C.); (J.J.T.-A.)
- Department of Medical Physiology and Biophysics, University of Seville, 41009 Seville, Spain
- Correspondence: (J.V.); (M.E.); Tel.: +34-955-920-034 (J.V.); +34-955-920-036 (M.E.)
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11
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Wang C, Wang X, Tan C, Wang Y, Tang Z, Zhang Z, Liu J, Xiao G. Novel therapeutics for hydrocephalus: Insights from animal models. CNS Neurosci Ther 2021; 27:1012-1022. [PMID: 34151523 PMCID: PMC8339528 DOI: 10.1111/cns.13695] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 05/09/2021] [Accepted: 06/02/2021] [Indexed: 02/06/2023] Open
Abstract
Hydrocephalus is a cerebrospinal fluid physiological disorder that causes ventricular dilation with normal or high intracranial pressure. The current regular treatment for hydrocephalus is cerebrospinal fluid shunting, which is frequently related to failure and complications. Meanwhile, considering that the current nonsurgical treatments of hydrocephalus can only relieve the symptoms but cannot eliminate this complication caused by primary brain injuries, the exploration of more effective therapies has become the focus for many researchers. In this article, the current research status and progress of nonsurgical treatment in animal models of hydrocephalus are reviewed to provide new orientations for animal research and clinical practice.
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Affiliation(s)
- Chuansen Wang
- Department of NeurosurgeryXiangya HospitalCentral South UniversityChangshaHunanChina
- Diagnosis and Treatment Center for HydrocephalusXiangya HospitalCentral South UniversityChangshaHunanChina
- National Clinical Research Center for Geriatric DisordersXiangya HospitalCentral South UniversityChangshaHunanChina
| | - Xiaoqiang Wang
- Department of Pediatric NeurosurgeryXinhua HospitalShanghai Jiaotong University School of MedicineShanghaiChina
| | - Changwu Tan
- Department of NeurosurgeryXiangya HospitalCentral South UniversityChangshaHunanChina
- Diagnosis and Treatment Center for HydrocephalusXiangya HospitalCentral South UniversityChangshaHunanChina
- National Clinical Research Center for Geriatric DisordersXiangya HospitalCentral South UniversityChangshaHunanChina
| | - Yuchang Wang
- Department of NeurosurgeryXiangya HospitalCentral South UniversityChangshaHunanChina
- Diagnosis and Treatment Center for HydrocephalusXiangya HospitalCentral South UniversityChangshaHunanChina
- National Clinical Research Center for Geriatric DisordersXiangya HospitalCentral South UniversityChangshaHunanChina
| | - Zhi Tang
- Department of NeurosurgeryHunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of MedicineCentral South UniversityChangshaHunanChina
| | - Zhiping Zhang
- Department of NeurosurgeryXiangya HospitalCentral South UniversityChangshaHunanChina
- Diagnosis and Treatment Center for HydrocephalusXiangya HospitalCentral South UniversityChangshaHunanChina
- National Clinical Research Center for Geriatric DisordersXiangya HospitalCentral South UniversityChangshaHunanChina
| | - Jingping Liu
- Department of NeurosurgeryXiangya HospitalCentral South UniversityChangshaHunanChina
- Diagnosis and Treatment Center for HydrocephalusXiangya HospitalCentral South UniversityChangshaHunanChina
- National Clinical Research Center for Geriatric DisordersXiangya HospitalCentral South UniversityChangshaHunanChina
| | - Gelei Xiao
- Department of NeurosurgeryXiangya HospitalCentral South UniversityChangshaHunanChina
- Diagnosis and Treatment Center for HydrocephalusXiangya HospitalCentral South UniversityChangshaHunanChina
- National Clinical Research Center for Geriatric DisordersXiangya HospitalCentral South UniversityChangshaHunanChina
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12
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Purohit D, Finkel DA, Malfa A, Liao Y, Ivanova L, Kleinman GM, Hu F, Shah S, Thompson C, Joseph E, Wolin MS, Cairo MS, La Gamma EF, Vinukonda G. Human Cord Blood Derived Unrestricted Somatic Stem Cells Restore Aquaporin Channel Expression, Reduce Inflammation and Inhibit the Development of Hydrocephalus After Experimentally Induced Perinatal Intraventricular Hemorrhage. Front Cell Neurosci 2021; 15:633185. [PMID: 33897371 PMCID: PMC8062878 DOI: 10.3389/fncel.2021.633185] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 03/22/2021] [Indexed: 11/13/2022] Open
Abstract
Intraventricular hemorrhage (IVH) is a severe complication of preterm birth associated with cerebral palsy, intellectual disability, and commonly, accumulation of cerebrospinal fluid (CSF). Histologically, IVH leads to subependymal gliosis, fibrosis, and disruption of the ependymal wall. Importantly, expression of aquaporin channels 1 and 4 (AQP1 and AQP4) regulating respectively, secretion and absorption of cerebrospinal fluids is altered with IVH and are associated with development of post hemorrhagic hydrocephalus. Human cord blood derived unrestricted somatic stem cells (USSCs), which we previously demonstrated to reduce the magnitude of hydrocephalus, as having anti-inflammatory, and beneficial behavioral effects, were injected into the cerebral ventricles of rabbit pups 18 h after glycerol-induced IVH. USSC treated IVH pups showed a reduction in ventricular size when compared to control pups at 7 and 14 days (both, P < 0.05). Histologically, USSC treatment reduced cellular infiltration and ependymal wall disruption. In the region of the choroid plexus, immuno-reactivity for AQP1 and ependymal wall AQP4 expression were suppressed after IVH but were restored following USSC administration. Effects were confirmed by analysis of mRNA from dissected choroid plexus and ependymal tissue. Transforming growth factor beta (TGF-β) isoforms, connective tissue growth factor (CTGF) and matrix metalloprotease-9 (MMP-9) mRNA, as well as protein levels, were significantly increased following IVH and restored towards normal with USSC treatment (P < 0.05). The anti-inflammatory cytokine Interleukin-10 (IL-10) mRNA was reduced in IVH, but significantly recovered after USSC injection (P < 0.05). In conclusion, USSCs exerted anti-inflammatory effects by suppressing both TGF-β specific isoforms, CTGF and MMP-9, recovered IL-10, restored aquaporins expression towards baseline, and reduced hydrocephalus. These results support the possibility of the use of USSCs to reduce IVH consequences in prematurity.
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Affiliation(s)
- Deepti Purohit
- The Regional Neonatal Center, Maria Fareri Children's Hospital at Westchester Medical Center, New York Medical College, Valhalla, NY, United States
| | - Dina A Finkel
- The Regional Neonatal Center, Maria Fareri Children's Hospital at Westchester Medical Center, New York Medical College, Valhalla, NY, United States
| | - Ana Malfa
- The Regional Neonatal Center, Maria Fareri Children's Hospital at Westchester Medical Center, New York Medical College, Valhalla, NY, United States
| | - Yanling Liao
- Department of Pediatrics, New York Medical College, Valhalla, NY, United States
| | - Larisa Ivanova
- Department of Pediatrics, New York Medical College, Valhalla, NY, United States
| | - George M Kleinman
- Department of Pathology, Westchester Medical Center, New York Medical College, Valhalla, NY, United States
| | - Furong Hu
- Department of Pediatrics, New York Medical College, Valhalla, NY, United States
| | - Shetal Shah
- The Regional Neonatal Center, Maria Fareri Children's Hospital at Westchester Medical Center, New York Medical College, Valhalla, NY, United States
| | - Carl Thompson
- Department of Physiology, New York Medical College, Valhalla, NY, United States
| | - Etlinger Joseph
- Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY, United States
| | - Michael S Wolin
- Department of Physiology, New York Medical College, Valhalla, NY, United States
| | - Mitchell S Cairo
- Department of Pediatrics, New York Medical College, Valhalla, NY, United States.,Departments of Medicine, Pathology, Microbiology and Immunology, New York Medical College, Valhalla, NY, United States
| | - Edmund F La Gamma
- The Regional Neonatal Center, Maria Fareri Children's Hospital at Westchester Medical Center, New York Medical College, Valhalla, NY, United States.,Department of Pediatrics, New York Medical College, Valhalla, NY, United States.,Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, United States
| | - Govindaiah Vinukonda
- Department of Pediatrics, New York Medical College, Valhalla, NY, United States.,Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY, United States
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13
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de Laurentis C, Cristaldi P, Arighi A, Cavandoli C, Trezza A, Sganzerla EP, Giussani CG, Di Cristofori A. Role of aquaporins in hydrocephalus: what do we know and where do we stand? A systematic review. J Neurol 2020; 268:4078-4094. [PMID: 32747978 DOI: 10.1007/s00415-020-10122-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 07/25/2020] [Accepted: 07/27/2020] [Indexed: 01/27/2023]
Abstract
INTRODUCTION Glymphatic fluid circulation may be considered the lymphatic system of the brain and the main role of such system seems to be played by aquaporins (AQPs), a family of proteins which regulates water exchange, in particular AQP4 and 1. Alterations of glymphatic fluid circulation through AQPs variations are now emerging as central elements in the pathophysiology of different brain conditions, like hydrocephalus. This systematic review provides an insight about the role of AQPs in hydrocephalus establishment and compensation, investigating their possible role as diagnostic tools or therapeutic targets. METHODS PubMed database was screened searching for the relevant existing literature in English language published until February 29th 2020, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement. RESULTS A total of 40 articles met the inclusion criteria for our systematic analysis. AQP4 resulted the most studied water channel, followed by AQP1. The changes in cerebrospinal fluid (CSF), brain parenchyma and choroid plexus (CP) in different hydrocephalus type were analyzed. Moreover, important pharmacological interactions regarding AQP and molecules or conditions were discussed. A very interesting result is the general consensus on increase of AQP4 in hydrocephalic patients, unless in patients suffering from idiopathic normal pressure hydrocephalus, where AQP4 shows a tendency in reduction. CONCLUSION AQP seem to play a central role in the pathophysiology of hydrocephalus and in its compensation mechanisms. Further studies are required to definitively establish their precise roles and their quantitative changes to allow their utilization as diagnostic tools or therapeutic targets.
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Affiliation(s)
- Camilla de Laurentis
- Unit of Neurosurgery, Ospedale San Gerardo, Azienda Socio Sanitaria Territoriale Monza, Via G. B. Pergolesi 33, 20900, Monza, MB, Italy.,Department of Surgery and Medicine, Università degli Studi Milano-Bicocca, Milan, MI, Italy
| | - Paola Cristaldi
- Unit of Neurosurgery, Ospedale San Gerardo, Azienda Socio Sanitaria Territoriale Monza, Via G. B. Pergolesi 33, 20900, Monza, MB, Italy.,Department of Surgery and Medicine, Università degli Studi Milano-Bicocca, Milan, MI, Italy
| | - Andrea Arighi
- Unit of Neurology - UOSD Malattie Neurodegenerative, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, MI, Italy.,Dino Ferrari Center - Università degli Studi di Milano, Milan, MI, Italy
| | - Clarissa Cavandoli
- Unit of Neurosurgery, Ospedale San Gerardo, Azienda Socio Sanitaria Territoriale Monza, Via G. B. Pergolesi 33, 20900, Monza, MB, Italy.,Università degli Studi di Milano, Milan, MI, Italy
| | - Andrea Trezza
- Unit of Neurosurgery, Ospedale San Gerardo, Azienda Socio Sanitaria Territoriale Monza, Via G. B. Pergolesi 33, 20900, Monza, MB, Italy
| | - Erik P Sganzerla
- Unit of Neurosurgery, Ospedale San Gerardo, Azienda Socio Sanitaria Territoriale Monza, Via G. B. Pergolesi 33, 20900, Monza, MB, Italy.,Department of Surgery and Medicine, Università degli Studi Milano-Bicocca, Milan, MI, Italy
| | - Carlo G Giussani
- Unit of Neurosurgery, Ospedale San Gerardo, Azienda Socio Sanitaria Territoriale Monza, Via G. B. Pergolesi 33, 20900, Monza, MB, Italy.,Department of Surgery and Medicine, Università degli Studi Milano-Bicocca, Milan, MI, Italy
| | - Andrea Di Cristofori
- Unit of Neurosurgery, Ospedale San Gerardo, Azienda Socio Sanitaria Territoriale Monza, Via G. B. Pergolesi 33, 20900, Monza, MB, Italy.
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14
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Gu C, Hao X, Li J, Hua Y, Keep RF, Xi G. Effects of minocycline on epiplexus macrophage activation, choroid plexus injury and hydrocephalus development in spontaneous hypertensive rats. J Cereb Blood Flow Metab 2019; 39:1936-1948. [PMID: 30862302 PMCID: PMC6775580 DOI: 10.1177/0271678x19836117] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 01/17/2019] [Accepted: 02/14/2019] [Indexed: 01/11/2023]
Abstract
Hydrocephalus has been reported to occur in spontaneous hypertensive rats (SHRs). The purposes of this study were (1) to use T2 magnetic resonance imaging to examine time of onset, (2) to elucidate potential underlying mechanisms and (3) to determine whether minocycline could prevent hydrocephalus development. Ventriculomegaly was evaluated by T2 imaging in SHRs and Wistar-Kyoto rats from weeks 4 to 7 after birth. Brain histology and transmission electron microscopy were used to assess the periventricular and choroid plexus damage. SHRs were also treated with either vehicle or minocycline. We found that hydrocephalus was observed in SHRs but not in Wistar-Kyoto rats. It occurred at seven weeks of age but was not present at four and five weeks. The hydrocephalus was associated with epiplexus cell (macrophage) activation, choroid plexus cell death and damage to the ventricle wall. Treatment with minocycline from week 5 attenuated hydrocephalus development and pathological changes in choroid plexus and ventricular wall at week 7. The current study found that spontaneous hydrocephalus arises at ∼7 weeks in male SHRs. The early development of hydrocephalus (persistent ventricular dilatation) may result from epiplexus cell activation, choroid plexus cell death and periventricular damage, which can be ameliorated by treatment with minocycline.
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Affiliation(s)
- Chi Gu
- Department of Neurosurgery, University of Michigan, Ann Arbor, MI, USA
- Department of Neurosurgery, the 2 Affiliated Hospital, Zhejiang University, Hangzhou, China
| | - Xiaodi Hao
- Department of Neurosurgery, University of Michigan, Ann Arbor, MI, USA
- Department of Neurology, the 2 Affiliated Hospital, Zhejiang University, Hangzhou, China
| | - Jianru Li
- Department of Neurosurgery, University of Michigan, Ann Arbor, MI, USA
- Department of Neurosurgery, the 2 Affiliated Hospital, Zhejiang University, Hangzhou, China
| | - Ya Hua
- Department of Neurosurgery, University of Michigan, Ann Arbor, MI, USA
| | - Richard F Keep
- Department of Neurosurgery, University of Michigan, Ann Arbor, MI, USA
| | - Guohua Xi
- Department of Neurosurgery, University of Michigan, Ann Arbor, MI, USA
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15
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Castañeyra-Ruiz L, Hernández-Abad LG, Carmona-Calero EM, Castañeyra-Perdomo A, González-Marrero I. AQP1 Overexpression in the CSF of Obstructive Hydrocephalus and Inversion of Its Polarity in the Choroid Plexus of a Chiari Malformation Type II Case. J Neuropathol Exp Neurol 2019; 78:641-647. [DOI: 10.1093/jnen/nlz033] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Leandro Castañeyra-Ruiz
- Department of Neurological Surgery, Washington University, School of Medicine and the St. Louis Children’s Hospital, St. Louis, Missouri
| | | | - Emilia M Carmona-Calero
- Departamento de Anatomía, Anatomía, Patológica e Histología, Facultad de Medicina, Universidad de La Laguna, La Laguna, Tenerife, Islas Canarias, Spain
| | - Agustín Castañeyra-Perdomo
- Departamento de Anatomía, Anatomía, Patológica e Histología, Facultad de Medicina, Universidad de La Laguna, La Laguna, Tenerife, Islas Canarias, Spain
| | - Ibrahim González-Marrero
- Departamento de Anatomía, Anatomía, Patológica e Histología, Facultad de Medicina, Universidad de La Laguna, La Laguna, Tenerife, Islas Canarias, Spain
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16
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Klebe D, McBride D, Krafft PR, Flores JJ, Tang J, Zhang JH. Posthemorrhagic hydrocephalus development after germinal matrix hemorrhage: Established mechanisms and proposed pathways. J Neurosci Res 2019; 98:105-120. [PMID: 30793349 DOI: 10.1002/jnr.24394] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 12/05/2018] [Accepted: 01/14/2019] [Indexed: 01/17/2023]
Abstract
In addition to being the leading cause of morbidity and mortality in premature infants, germinal matrix hemorrhage (GMH) is also the leading cause of acquired infantile hydrocephalus. The pathophysiology of posthemorrhagic hydrocephalus (PHH) development after GMH is complex and vaguely understood, although evidence suggests fibrosis and gliosis in the periventricular and subarachnoid spaces disrupts normal cerebrospinal fluid (CSF) dynamics. Theories explaining general hydrocephalus etiology have substantially evolved from the original bulk flow theory developed by Dr. Dandy over a century ago. Current clinical and experimental evidence supports a new hydrodynamic theory for hydrocephalus development involving redistribution of vascular pulsations and disruption of Starling forces in the brain microcirculation. In this review, we discuss CSF flow dynamics, history and development of theoretical hydrocephalus pathophysiology, and GMH epidemiology and etiology as it relates to PHH development. We highlight known mechanisms and propose new avenues that will further elucidate GMH pathophysiology, specifically related to hydrocephalus.
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Affiliation(s)
- Damon Klebe
- Department of Physiology and Pharmacology, Loma Linda University School of Medicine, Loma Linda, California
| | - Devin McBride
- Department of Physiology and Pharmacology, Loma Linda University School of Medicine, Loma Linda, California
| | - Paul R Krafft
- Department of Physiology and Pharmacology, Loma Linda University School of Medicine, Loma Linda, California.,Department of Neurosurgery, Loma Linda University School of Medicine, Loma Linda, California
| | - Jerry J Flores
- Department of Physiology and Pharmacology, Loma Linda University School of Medicine, Loma Linda, California
| | - Jiping Tang
- Department of Physiology and Pharmacology, Loma Linda University School of Medicine, Loma Linda, California
| | - John H Zhang
- Department of Physiology and Pharmacology, Loma Linda University School of Medicine, Loma Linda, California.,Department of Anesthesiology and Neurosurgery, Loma Linda University School of Medicine, Loma Linda, California
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17
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Aquaporin-4 Water Channel in the Brain and Its Implication for Health and Disease. Cells 2019; 8:cells8020090. [PMID: 30691235 PMCID: PMC6406241 DOI: 10.3390/cells8020090] [Citation(s) in RCA: 128] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 01/23/2019] [Accepted: 01/23/2019] [Indexed: 02/08/2023] Open
Abstract
Aquaporin-4 (AQP4) is a water channel expressed on astrocytic endfeet in the brain. The role of AQP4 has been studied in health and in a range of pathological conditions. Interest in AQP4 has increased since it was discovered to be the target antigen in the inflammatory autoimmune disease neuromyelitis optica spectrum disorder (NMOSD). Emerging data suggest that AQP4 may also be implicated in the glymphatic system and may be involved in the clearance of beta-amyloid in Alzheimer’s disease (AD). In this review, we will describe the role of AQP4 in the adult and developing brain as well as its implication for disease.
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18
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Rizwan Siddiqui M, Attar F, Mohanty V, Kim KS, Shekhar Mayanil C, Tomita T. Erythropoietin-mediated activation of aquaporin-4 channel for the treatment of experimental hydrocephalus. Childs Nerv Syst 2018; 34:2195-2202. [PMID: 29982881 PMCID: PMC6208663 DOI: 10.1007/s00381-018-3865-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 06/06/2018] [Indexed: 01/18/2023]
Abstract
OBJECTIVE In this study, we investigate a neuroprotective agent, erythropoietin (EPO), in animal hydrocephalus model and its potential reversal effects on hydrocephalus by altering the expression of aquaporin-4 (AQP4). METHODS Obstructive hydrocephalus was induced in 2-week-old rat pups by injecting kaolin (50 μl, 10 mg/ml in saline) into the cisterna magna, while the control pups received only saline. Kaolin-injected pups were divided into two groups on the fifth day after kaolin injection; one group received intra-peritoneal (i.p.) EPO (1 μg/pup) for 5 consecutive days, while other group received i.p. saline for 5 days. The effects of EPO on hydrocephalus were investigated by studying cerebral ventricle size and structural ependymal changes. We examined also the EPO effects on AQP4 expression and microRNA expression. RESULTS EPO treatment significantly reduced dilation of the cerebral ventricle and denudation of ependymal line in hydrocephalic pups comparing with the control group. Increased expression of AQP4 in periventricular ependymal lining and cultured astrocytes and increased vascular formation were noted after EPO treatment. Additionally, we identified miR-668 as an endogenous regulator of AQP4 in response to EPO. Anti-miR-668 dampened EPO-induced activation of AQP4 expression. CONCLUSIONS Together, our results show that EPO-mediated upregulation of AQP4 significantly reduces dilation of the cerebral ventricles in obstructive hydrocephalus pups and may lead to potential therapeutic options for hydrocephalus.
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Affiliation(s)
- M Rizwan Siddiqui
- Pediatric Neurosurgery Research Program, Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Childrens' Hospital of Chicago, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Furqan Attar
- Pediatric Neurosurgery Research Program, Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Childrens' Hospital of Chicago, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Vineet Mohanty
- Pediatric Neurosurgery Research Program, Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Childrens' Hospital of Chicago, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Kwang Sik Kim
- Division of Pediatric Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - C Shekhar Mayanil
- Pediatric Neurosurgery Research Program, Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Childrens' Hospital of Chicago, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
- Division of Pediatric Neurosurgery, Ann & Robert H. Lurie Children's Hospital of Chicago, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Tadanori Tomita
- Pediatric Neurosurgery Research Program, Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Childrens' Hospital of Chicago, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
- Division of Pediatric Neurosurgery, Ann & Robert H. Lurie Children's Hospital of Chicago, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
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19
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Saadeh FS, Melamed EF, Rea ND, Krieger MD. Seizure outcomes of supratentorial brain tumor resection in pediatric patients. Neuro Oncol 2018; 20:1272-1281. [PMID: 29579305 PMCID: PMC6071648 DOI: 10.1093/neuonc/noy026] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Background This study aims to identify the prevalence of and risk factors for seizure development after supratentorial brain tumor resection in pediatric patients. This could be used to guide the postoperative management and usage of anti-epileptic drugs (AEDs). Methods Retrospective study was conducted for patients between 0 and 21 years with supratentorial tumor resection between 2005 and 2015 at a single institution. Results Two hundred patients (114 males/86 females) were identified. Median age at resection (±SD) was 9.025 ± 5.720 years and mean follow-up was 4 ± 2 years. Resection was gross total in 82 patients (41%) and partial in 118 patients (59%); 66 patients (33%) experienced preoperative seizures, and 67 patients (34%) experienced postoperative seizures; 18 patients (27%) had early seizures, and 49 patients (73%) had late seizures. Univariate analysis identified risk factors for postoperative seizures as: preoperative seizures (P < 0.001), age less than 2 years (P = 0.003), temporal location (P < 0.001), thalamic location (P = 0.017), preoperative hyponatremia (P = 0.017), World Health Organization grade (P = 0.008), and pathology (P = 0.005). Multivariate regression identified 5 robust risk factors: temporal location (odds ratio [OR] 4.7, 95% CI: 1.7-13.3, P = 0.003), age <2 years (OR 3.9, 95% CI: 1.0-15.4; P = 0.049), preoperative hydrocephalus (OR 3.8, 95% CI: 1.5-9.4; P = 0.005), preoperative seizure (OR 2.8, 95% CI: 1.2-6.5; P = 0.016) and parietal location (OR 0.25, 95% CI: 0.06-0.99; P = 0.049). Extent of resection did not correlate with seizure development (P > 0.05). Conclusions This study reveals 5 risk factors for postoperative seizures after resection of supratentorial tumors. These factors should be considered in postoperative management of these patients.
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Affiliation(s)
- Fadi S Saadeh
- Division of Neurosurgery, Children’s Hospital of Los Angeles, Los Angeles, California
- Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Edward F Melamed
- Division of Neurosurgery, Children’s Hospital of Los Angeles, Los Angeles, California
- Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Nolan D Rea
- Division of Neurosurgery, Children’s Hospital of Los Angeles, Los Angeles, California
- Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Mark D Krieger
- Division of Neurosurgery, Children’s Hospital of Los Angeles, Los Angeles, California
- Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California
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20
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Guo J, Mi X, Zhan R, Li M, Wei L, Sun J. Aquaporin 4 Silencing Aggravates Hydrocephalus Induced by Injection of Autologous Blood in Rats. Med Sci Monit 2018; 24:4204-4212. [PMID: 29921834 PMCID: PMC6042309 DOI: 10.12659/msm.906936] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Accepted: 12/11/2017] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Aquaporin 4 (AQP4), the most abundant aquaporin in the brain, is a type of bidirectional water channel controlling the brain-water balance and plays a critical role in physiologic and pathologic water balance in the brain. AQP4 was reported to be elevated in hydrocephalus; therefore, we hypothesized that AQP4 contributes to hydrocephalus. In this study, the role of AQP4 in hydrocephalus was explored. MATERIAL AND METHODS The hydrocephalus rat model was established by injection of autologous blood. On Day 1 and Day 3 after injection of autologous blood, magnetic resonance imaging (MRI) and hematoxylin-eosin (HE) staining were performed to detect the changes in ventricles, and quantitative real-time PCR (qRT-PCR) and immunohistochemistry were carried out to detect the changes in AQP4 level. Thereafter, an AQP4-specific siRNA was used to downregulate AQP4. Then, on Day 3 after injection of autologous blood, the levels of AQP4 and connexin-43 were detected by qRT-PCR, immunohistochemistry, immunofluorescence, or Western blot analysis. MRI and HE staining were performed to detect the changes in ventricles, and Evans blue extravasation assay was used to assess blood-brain barrier integrity. RESULTS The hydrocephalus rat model was established successfully, and hydrocephalus rats showed a higher AQP4 level. Silencing AQP4 aggravated the hydrocephalus, with enlarged lateral ventricles and destruction of ependymal integrity and blood-brain barrier. CONCLUSIONS Our study demonstrates that silencing AQP4 aggravates hydrocephalus, indicating that AQP4 protects against hydrocephalus.
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Affiliation(s)
- Jian Guo
- First Department of Neurosurgery, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong, P.R. China
| | - Xinjiang Mi
- Second Department of Surgery, Shandong Police Hospital, Jinan, Shandong, P.R. China
| | - Rucai Zhan
- Second Department of Neurosurgery, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong, P.R. China
| | - Meng Li
- First Department of Neurosurgery, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong, P.R. China
| | - Lin Wei
- First Department of Neurosurgery, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong, P.R. China
| | - Jinlong Sun
- First Department of Neurosurgery, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong, P.R. China
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21
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Zhao L, Li D, Liu N, Liu L, Zhang Z, Gao C, Kawano H, Zhou FY, Li HP. Correlation of TGN-020 with the analgesic effects via ERK pathway activation after chronic constriction injury. Mol Pain 2018; 14:1744806918796057. [PMID: 30152258 PMCID: PMC6113736 DOI: 10.1177/1744806918796057] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 07/17/2018] [Accepted: 07/27/2018] [Indexed: 02/06/2023] Open
Abstract
Extracellular regulated protein kinase (ERK) pathway activation in astrocytes and neurons has been reported to be critical for neuropathic pain development after chronic constriction injury. TGN-020 was found to be the most potent aquaporin 4 inhibitor among the agents studied. The present study aimed to assess whether the inhibition of aquaporin 4 had an analgesic effect on neuropathic pain and whether the inhibition of astrocytic activation and ERK pathway was involved in the analgesic effect of TGN-020. We thus found that TGN-020 upregulated the threshold of thermal and mechanical allodynia, downregulated the expression of interleukin-1β, interleukin-6, and tumor necrosis factor-α, attenuated the astrocytic activation and suppressed the activation of mitogen-activated protein kinase pathways in the spinal dorsal horn and dorsal root ganglion. Additionally, TGN-020 suppressed ERK phosphorylation in astrocytes and neurons after injury. The findings suggested that the analgesic effects of TGN-020 in neuropathic pain were mediated mainly by the downregulation of chronic constriction injury-induced astrocytic activation and inflammation, which is via the inhibition of ERK pathway in the spinal dorsal horn and dorsal root ganglion.
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Affiliation(s)
- Liang Zhao
- Department of Human Anatomy, College of Basic Medical Sciences,
China Medical University, Shenyang, China
- Department of Orthopedic Surgery, Shenyang Fifth People’s
Hospital, Shenyang, China
| | - Dan Li
- Department of Human Anatomy, College of Basic Medical Sciences,
China Medical University, Shenyang, China
| | - Nan Liu
- Department of Human Anatomy, College of Basic Medical Sciences,
China Medical University, Shenyang, China
| | - Lu Liu
- Department of Human Anatomy, College of Basic Medical Sciences,
China Medical University, Shenyang, China
| | - Zhuo Zhang
- Department of Human Anatomy, College of Basic Medical Sciences,
China Medical University, Shenyang, China
| | - Chao Gao
- Department of Human Anatomy, College of Basic Medical Sciences,
China Medical University, Shenyang, China
| | - Hitoshi Kawano
- Department of Health and Dietetics, Faculty of Health and
Medical Science, Teikyo Heisei University, Tokyo, Japan
| | - Fang-Yuan Zhou
- Department of Human Anatomy, College of Basic Medical Sciences,
China Medical University, Shenyang, China
| | - Hong-Peng Li
- Department of Human Anatomy, College of Basic Medical Sciences,
China Medical University, Shenyang, China
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22
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Jeon T, Park KS, Park SH, Hwang JH, Hwang SK. Expression of Aquaporin 1 and 4 in the Choroid Plexus and Brain Parenchyma of Kaolin-Induced Hydrocephalic Rats. Korean J Neurotrauma 2017; 13:68-75. [PMID: 29201837 PMCID: PMC5702761 DOI: 10.13004/kjnt.2017.13.2.68] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 07/09/2017] [Accepted: 07/14/2017] [Indexed: 11/15/2022] Open
Abstract
Objective Aquaporin (AQP) is a recently discovered protein that regulates water homeostasis. The present study examines changes in AQP 1 and 4 in kaolin induced experimental hydrocephalic rats to elucidate the pathophysiology of water homeostasis in the disease. Methods Hydrocephalus was induced by percutaneous intracisternal injection of kaolin. The brain parenchyma and choroid plexus were obtained at 3, 7, 14 and 30 days after injection. Protein expressions of AQP 1 and 4 were measured by western blot, immunohistochemistry (IHC) and immunofluorescence (IF) stains. Results In the choroid plexus of the kaolin-induced hydrocephalus group, AQP 1 expression identified by western blot exhibited sharp decrease in the early stage (55% by the 3rd day and 22% by the 7th day), but indicated a 2.2-fold increase in the later stage (30th day) in comparison with control groups. In the parenchyma, a quantitative measurement of AQP 4 expression revealed variable results on the 3rd and 7th days, but indicated expression 2.1 times higher than the control in the later stage (30th day). In addition, the IHC and IF findings supported the patterns of expression of AQP 1 in the choroid plexus and AQP 4 in the parenchyma. Conclusion Expression of AQP 1 decreased sharply in the choroid plexus of acute hydrocephalus rats and increased at later stages. Expression of AQP 4 in the brain parenchyma was variable in the early stage in the hydrocephalus group, but was higher than in the control in the later stage. These findings suggest a compensating role of AQPs in water physiology in hydrocephalus.
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Affiliation(s)
- Taehyung Jeon
- Department of Neurosurgery, Kyungpook National Univeristy Hospital, Daegu, Korea
| | - Ki-Su Park
- Department of Neurosurgery, Kyungpook National Univeristy Hospital, Daegu, Korea
| | - Seong-Hyun Park
- Department of Neurosurgery, Kyungpook National Univeristy Hospital, Daegu, Korea
| | - Jeong-Hyun Hwang
- Department of Neurosurgery, Kyungpook National Univeristy Hospital, Daegu, Korea
| | - Sung Kyoo Hwang
- Department of Neurosurgery, Kyungpook National Univeristy Hospital, Daegu, Korea
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23
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Sun BL, Wang LH, Yang T, Sun JY, Mao LL, Yang MF, Yuan H, Colvin RA, Yang XY. Lymphatic drainage system of the brain: A novel target for intervention of neurological diseases. Prog Neurobiol 2017; 163-164:118-143. [PMID: 28903061 DOI: 10.1016/j.pneurobio.2017.08.007] [Citation(s) in RCA: 144] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 08/11/2017] [Accepted: 08/31/2017] [Indexed: 12/20/2022]
Abstract
The belief that the vertebrate brain functions normally without classical lymphatic drainage vessels has been held for many decades. On the contrary, new findings show that functional lymphatic drainage does exist in the brain. The brain lymphatic drainage system is composed of basement membrane-based perivascular pathway, a brain-wide glymphatic pathway, and cerebrospinal fluid (CSF) drainage routes including sinus-associated meningeal lymphatic vessels and olfactory/cervical lymphatic routes. The brain lymphatic systems function physiological as a route of drainage for interstitial fluid (ISF) from brain parenchyma to nearby lymph nodes. Brain lymphatic drainage helps maintain water and ion balance of the ISF, waste clearance, and reabsorption of macromolecular solutes. A second physiological function includes communication with the immune system modulating immune surveillance and responses of the brain. These physiological functions are influenced by aging, genetic phenotypes, sleep-wake cycle, and body posture. The impairment and dysfunction of the brain lymphatic system has crucial roles in age-related changes of brain function and the pathogenesis of neurovascular, neurodegenerative, and neuroinflammatory diseases, as well as brain injury and tumors. In this review, we summarize the key component elements (regions, cells, and water transporters) of the brain lymphatic system and their regulators as potential therapeutic targets in the treatment of neurologic diseases and their resulting complications. Finally, we highlight the clinical importance of ependymal route-based targeted gene therapy and intranasal drug administration in the brain by taking advantage of the unique role played by brain lymphatic pathways in the regulation of CSF flow and ISF/CSF exchange.
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Affiliation(s)
- Bao-Liang Sun
- Key Laboratory of Cerebral Microcirculation in Universities of Shandong (Taishan Medical University), Department of Neurology, Affiliated Hospital of Taishan Medical University, Tai'an, Shandong 271000, China.
| | - Li-Hua Wang
- Affiliated Hospital of Weifang Medical University, Weifang, Shandong 261031, China
| | - Tuo Yang
- Center of Cerebrovascular Disease Research, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Jing-Yi Sun
- Wonju Severance Christian Hospital, Yonsei University Wonju College of Medicine, Wonju, Gangwon 220-701, Republic of Korea
| | - Lei-Lei Mao
- Key Laboratory of Cerebral Microcirculation in Universities of Shandong (Taishan Medical University), Department of Neurology, Affiliated Hospital of Taishan Medical University, Tai'an, Shandong 271000, China
| | - Ming-Feng Yang
- Key Laboratory of Cerebral Microcirculation in Universities of Shandong (Taishan Medical University), Department of Neurology, Affiliated Hospital of Taishan Medical University, Tai'an, Shandong 271000, China
| | - Hui Yuan
- Key Laboratory of Cerebral Microcirculation in Universities of Shandong (Taishan Medical University), Department of Neurology, Affiliated Hospital of Taishan Medical University, Tai'an, Shandong 271000, China
| | - Robert A Colvin
- Department of Biological Sciences, Interdisciplinary Graduate Program in Molecular and Cellular Biology, Neuroscience Program, Ohio University, Athens, OH 45701, USA
| | - Xiao-Yi Yang
- Key Laboratory of Cerebral Microcirculation in Universities of Shandong (Taishan Medical University), Department of Neurology, Affiliated Hospital of Taishan Medical University, Tai'an, Shandong 271000, China.
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24
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Salman MM, Sheilabi MA, Bhattacharyya D, Kitchen P, Conner AC, Bill RM, Woodroofe MN, Conner MT, Princivalle AP. Transcriptome analysis suggests a role for the differential expression of cerebral aquaporins and the MAPK signalling pathway in human temporal lobe epilepsy. Eur J Neurosci 2017; 46:2121-2132. [PMID: 28715131 DOI: 10.1111/ejn.13652] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 07/10/2017] [Accepted: 07/11/2017] [Indexed: 01/12/2023]
Abstract
Epilepsies are common disorders of the central nervous system (CNS), affecting up to 2% of the global population. Pharmaco-resistance is a major clinical challenge affecting about 30% of temporal lobe epilepsy (TLE) patients. Water homeostasis has been shown crucial for regulation of neuronal excitability. The control of water movement is achieved through a family of small integral membrane channel proteins called aquaporins (AQPs). Despite the fact that changes in water homeostasis occur in sclerotic hippocampi of people with TLE, the expression of AQPs in the epileptic brain is not fully characterised. This study uses microarray and ELISA methods to analyse the mRNA and protein expression of the human cerebral AQPs in sclerotic hippocampi (TLE-HS) and adjacent neocortex tissue (TLE-NC) of TLE patients. The expression of AQP1 and AQP4 transcripts was significantly increased, while that of the AQP9 transcript was significantly reduced in TLE-HS compared to TLE-NC. AQP4 protein expression was also increased while expression of AQP1 protein remained unchanged, and AQP9 was undetected. Microarray data analysis identified 3333 differentially regulated genes and suggested the involvement of the MAPK signalling pathway in TLE pathogenesis. Proteome array data validated the translational profile for 26 genes and within the MAPK pathway (e.g. p38, JNK) that were identified as differentially expressed from microarray analysis. ELISA data showed that p38 and JNK inhibitors decrease AQP4 protein levels in cultured human primary cortical astrocytes. Elucidating the mechanism of selective regulation of different AQPs and associated regulatory proteins may provide a new therapeutic approach to epilepsy treatment.
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Affiliation(s)
- Mootaz M Salman
- Biomolecular Sciences Research Centre (BMRC), Sheffield Hallam University, Howard Street, Sheffield, S1 1WB, UK
| | - Mariam A Sheilabi
- Biomolecular Sciences Research Centre (BMRC), Sheffield Hallam University, Howard Street, Sheffield, S1 1WB, UK
| | | | - Philip Kitchen
- School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, UK
| | - Alex C Conner
- School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, UK
| | - Roslyn M Bill
- School of Life and Health Sciences, Aston University, Birmingham, UK
| | - M Nicola Woodroofe
- Biomolecular Sciences Research Centre (BMRC), Sheffield Hallam University, Howard Street, Sheffield, S1 1WB, UK
| | - Matthew T Conner
- Biomolecular Sciences Research Centre (BMRC), Sheffield Hallam University, Howard Street, Sheffield, S1 1WB, UK.,Research Institute of Health Sciences, School of Sciences, University of Wolverhampton, Wolverhampton, UK
| | - Alessandra P Princivalle
- Biomolecular Sciences Research Centre (BMRC), Sheffield Hallam University, Howard Street, Sheffield, S1 1WB, UK
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25
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Abstract
Posthemorrhagic hydrocephalus is a severe complication following intracranial hemorrhage. Posthemorrhagic hydrocephalus is often associated with high morbidity and mortality and serves as an important clinical predictor of adverse outcomes after intracranial hemorrhage. Currently, no effective medical intervention exists to improve functional outcomes in posthemorrhagic hydrocephalus patients because little is still known about the mechanisms of posthemorrhagic hydrocephalus pathogenesis. Because a better understanding of the posthemorrhagic hydrocephalus pathogenesis would facilitate development of clinical treatments, this is an active research area. The purpose of this review is to describe recent progress in elucidation of molecular mechanisms that cause posthemorrhagic hydrocephalus. What we are certain of is that the entry of blood into the ventricular system and subarachnoid space results in release of lytic blood products which cause a series of physiological and pathological changes in the brain. Blood components that can be linked to pathology would serve as disease biomarkers. From studies of posthemorrhagic hydrocephalus, such biomarkers are known to mutually synergize to initiate and promote posthemorrhagic hydrocephalus progression. These findings suggest that modulation of biomarker expression or function may benefit posthemorrhagic hydrocephalus patients.
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Affiliation(s)
- Cong Hua
- Department of Neurosurgery of the First Clinical Hospital, Jilin University, Changchun, China
| | - Gang Zhao
- Department of Neurosurgery of the First Clinical Hospital, Jilin University, Changchun, China
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26
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Karimy JK, Duran D, Hu JK, Gavankar C, Gaillard JR, Bayri Y, Rice H, DiLuna ML, Gerzanich V, Marc Simard J, Kahle KT. Cerebrospinal fluid hypersecretion in pediatric hydrocephalus. Neurosurg Focus 2017; 41:E10. [PMID: 27798982 DOI: 10.3171/2016.8.focus16278] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Hydrocephalus, despite its heterogeneous causes, is ultimately a disease of disordered CSF homeostasis that results in pathological expansion of the cerebral ventricles. Our current understanding of the pathophysiology of hydrocephalus is inadequate but evolving. Over this past century, the majority of hydrocephalus cases has been explained by functional or anatomical obstructions to bulk CSF flow. More recently, hydrodynamic models of hydrocephalus have emphasized the role of abnormal intracranial pulsations in disease pathogenesis. Here, the authors review the molecular mechanisms of CSF secretion by the choroid plexus epithelium, the most efficient and actively secreting epithelium in the human body, and provide experimental and clinical evidence for the role of increased CSF production in hydrocephalus. Although the choroid plexus epithelium might have only an indirect influence on the pathogenesis of many types of pediatric hydrocephalus, the ability to modify CSF secretion with drugs newer than acetazolamide or furosemide would be an invaluable component of future therapies to alleviate permanent shunt dependence. Investigation into the human genetics of developmental hydrocephalus and choroid plexus hyperplasia, and the molecular physiology of the ion channels and transporters responsible for CSF secretion, might yield novel targets that could be exploited for pharmacotherapeutic intervention.
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Affiliation(s)
| | | | | | | | | | - Yasar Bayri
- Department of Neurosurgery, Marmara University School of Medicine, Istanbul, Turkey; and
| | | | | | | | - J Marc Simard
- Departments of 3 Neurosurgery and.,Pathology and Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Kristopher T Kahle
- Departments of 1 Neurosurgery and.,Pediatrics, Cellular, and Molecular Physiology and Centers for Mendelian Genomics, Yale School of Medicine, New Haven, Connecticut
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27
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Verkman AS, Tradtrantip L, Smith AJ, Yao X. Aquaporin Water Channels and Hydrocephalus. Pediatr Neurosurg 2017; 52:409-416. [PMID: 27978530 PMCID: PMC5969073 DOI: 10.1159/000452168] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 09/21/2016] [Indexed: 01/10/2023]
Abstract
The aquaporins (AQPs) are a family of water-transporting proteins that are broadly expressed in mammalian cells. Two AQPs in the central nervous system, AQP1 and AQP4, might play a role in hydrocephalus and are thus potential drug targets. AQP1 is expressed in the ventricular-facing membrane of choroid plexus epithelial cells, where it facilitates the secretion of cerebrospinal fluid (CSF). AQP4 is expressed in astrocyte foot processes and ependymal cells lining ventricles, where it appears to facilitate the transport of excess water out of the brain. Altered expression of these AQPs in experimental animal models of hydrocephalus and limited human specimens suggests their involvement in the pathophysiology of hydrocephalus, as do data in knockout mice demonstrating a protective effect of AQP1 deletion and a deleterious effect of AQP4 deletion in hydrocephalus. Though significant questions remain, including the precise contribution of AQP1 to CSF secretion in humans and the mechanisms by which AQP4 facilitates clearance of excess brain water, AQP1 and AQP4 have been proposed as potential drug targets to reduce ventricular enlargement in hydrocephalus.
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Affiliation(s)
- Alan S Verkman
- Departments of Medicine and Physiology, University of California, San Francisco, CA, USA
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28
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Filippidis AS, Carozza RB, Rekate HL. Aquaporins in Brain Edema and Neuropathological Conditions. Int J Mol Sci 2016; 18:ijms18010055. [PMID: 28036023 PMCID: PMC5297690 DOI: 10.3390/ijms18010055] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 12/20/2016] [Accepted: 12/20/2016] [Indexed: 01/22/2023] Open
Abstract
The aquaporin (AQP) family of water channels are a group of small, membrane-spanning proteins that are vital for the rapid transport of water across the plasma membrane. These proteins are widely expressed, from tissues such as the renal epithelium and erythrocytes to the various cells of the central nervous system. This review will elucidate the basic structure and distribution of aquaporins and discuss the role of aquaporins in various neuropathologies. AQP1 and AQP4, the two primary aquaporin molecules of the central nervous system, regulate brain water and CSF movement and contribute to cytotoxic and vasogenic edema, where they control the size of the intracellular and extracellular fluid volumes, respectively. AQP4 expression is vital to the cellular migration and angiogenesis at the heart of tumor growth; AQP4 is central to dysfunctions in glutamate metabolism, synaptogenesis, and memory consolidation; and AQP1 and AQP4 adaptations have been seen in obstructive and non-obstructive hydrocephalus and may be therapeutic targets.
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Affiliation(s)
- Aristotelis S Filippidis
- Division of Neurosurgery, Beth Israel Deaconess Medical School, Harvard Medical School, Boston, MA 02115, USA.
- Department of Neurosurgery, Boston Medical Center, Boston University, Boston, MA 02215, USA.
| | | | - Harold L Rekate
- Department of Neurosurgery, The Chiari Institute, Hofstra Northwell School of Medicine, Hempstead, NY 11549, USA.
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29
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Desai B, Hsu Y, Schneller B, Hobbs JG, Mehta AI, Linninger A. Hydrocephalus: the role of cerebral aquaporin-4 channels and computational modeling considerations of cerebrospinal fluid. Neurosurg Focus 2016; 41:E8. [DOI: 10.3171/2016.7.focus16191] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Aquaporin-4 (AQP4) channels play an important role in brain water homeostasis. Water transport across plasma membranes has a critical role in brain water exchange of the normal and the diseased brain. AQP4 channels are implicated in the pathophysiology of hydrocephalus, a disease of water imbalance that leads to CSF accumulation in the ventricular system. Many molecular aspects of fluid exchange during hydrocephalus have yet to be firmly elucidated, but review of the literature suggests that modulation of AQP4 channel activity is a potentially attractive future pharmaceutical therapy. Drug therapy targeting AQP channels may enable control over water exchange to remove excess CSF through a molecular intervention instead of by mechanical shunting. This article is a review of a vast body of literature on the current understanding of AQP4 channels in relation to hydrocephalus, details regarding molecular aspects of AQP4 channels, possible drug development strategies, and limitations. Advances in medical imaging and computational modeling of CSF dynamics in the setting of hydrocephalus are summarized. Algorithmic developments in computational modeling continue to deepen the understanding of the hydrocephalus disease process and display promising potential benefit as a tool for physicians to evaluate patients with hydrocephalus.
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Affiliation(s)
| | - Ying Hsu
- 2Bioengineering, University of Illinois at Chicago; and
| | | | | | | | - Andreas Linninger
- Departments of 1Neurosurgery and
- 2Bioengineering, University of Illinois at Chicago; and
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30
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Schmidt MJ, Rummel C, Hauer J, Kolecka M, Ondreka N, McClure V, Roth J. Increased CSF aquaporin-4, and interleukin-6 levels in dogs with idiopathic communicating internal hydrocephalus and a decrease after ventriculo-peritoneal shunting. Fluids Barriers CNS 2016; 13:12. [PMID: 27357498 PMCID: PMC4928270 DOI: 10.1186/s12987-016-0034-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 05/30/2016] [Indexed: 12/03/2022] Open
Abstract
Background Studies in animal models, in which internal hydrocephalus has been induced by obstructing the cerebrospinal fluid pathways, have documented an up-regulation of the concentrations of aquaporin-4 (AQP4) in the brain. In this study, the concentrations of aquaporin-1 (AQP1), AQP1, AQP4 and interleukin-6 (IL-6) were determined in the CSF of dogs with idiopathic communicating hydrocephalus before and after the reduction of intraventricular volume following ventriculo-peritoneal shunt (VP-shunt) treatment. Results The concentrations of AQP4 and IL-6 were increased in the cerebrospinal fluid of dogs with hydrocephalus compared to controls. Both parameters significantly decreased after surgical treatment, accompanied by decrease of ventricular size and the clinical recovery of the dogs. AQP1 was not detectable in CSF. Conclusions Brain AQP4 up-regulation might be a compensatory response in dogs with hydrocephalus. Future determination of AQP4 at the mRNA and protein level in brain tissue is warranted to substantiate this hypothesis.
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Affiliation(s)
- Martin J Schmidt
- Department of Veterinary Clinical Sciences, Small Animal Clinic, Justus-Liebig-University, Frankfurter Strasse 108, 35392, Giessen, Germany.
| | - Christoph Rummel
- Institute for Veterinary Physiology and Biochemistry, Justus-Liebig-University, Frankfurter Strasse 100, 35392, Giessen, Germany
| | - Jessica Hauer
- Department of Veterinary Clinical Sciences, Small Animal Clinic, Justus-Liebig-University, Frankfurter Strasse 108, 35392, Giessen, Germany
| | - Malgorzata Kolecka
- Department of Veterinary Clinical Sciences, Small Animal Clinic, Justus-Liebig-University, Frankfurter Strasse 108, 35392, Giessen, Germany
| | - Nele Ondreka
- Department of Veterinary Clinical Sciences, Small Animal Clinic, Justus-Liebig-University, Frankfurter Strasse 108, 35392, Giessen, Germany
| | - Vanessa McClure
- Department of Companion Animal Clinical Studies, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, Pretoria, 0110, Republic of South Africa
| | - Joachim Roth
- Institute for Veterinary Physiology and Biochemistry, Justus-Liebig-University, Frankfurter Strasse 100, 35392, Giessen, Germany
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31
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Xu H. New concept of the pathogenesis and therapeutic orientation of acquired communicating hydrocephalus. Neurol Sci 2016; 37:1387-91. [DOI: 10.1007/s10072-016-2589-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 04/19/2016] [Indexed: 12/12/2022]
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32
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Abstract
Hydrocephalus is a common disorder of cerebral spinal fluid (CSF) physiology resulting in abnormal expansion of the cerebral ventricles. Infants commonly present with progressive macrocephaly whereas children older than 2 years generally present with signs and symptoms of intracranial hypertension. The classic understanding of hydrocephalus as the result of obstruction to bulk flow of CSF is evolving to models that incorporate dysfunctional cerebral pulsations, brain compliance, and newly characterised water-transport mechanisms. Hydrocephalus has many causes. Congenital hydrocephalus, most commonly involving aqueduct stenosis, has been linked to genes that regulate brain growth and development. Hydrocephalus can also be acquired, mostly from pathological processes that affect ventricular outflow, subarachnoid space function, or cerebral venous compliance. Treatment options include shunt and endoscopic approaches, which should be individualised to the child. The long-term outcome for children that have received treatment for hydrocephalus varies. Advances in brain imaging, technology, and understanding of the pathophysiology should ultimately lead to improved treatment of the disorder.
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Affiliation(s)
- Kristopher T Kahle
- Department of Neurosurgery, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Abhaya V Kulkarni
- Division of Neurosurgery, Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - David D Limbrick
- Division of Neurosurgery, St Louis Children's Hospital, Washington University School of Medicine, St Louis, MO, USA
| | - Benjamin C Warf
- Department of Neurosurgery, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
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33
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Bu Y, Chen M, Gao T, Wang X, Li X, Gao F. Mechanisms of hydrocephalus after intraventricular haemorrhage in adults. Stroke Vasc Neurol 2016; 1:23-27. [PMID: 28959460 PMCID: PMC5435187 DOI: 10.1136/svn-2015-000003] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 02/01/2016] [Accepted: 02/02/2016] [Indexed: 11/04/2022] Open
Abstract
Intraventricular haemorrhage (IVH) is defined as the eruption of blood in the cerebroventricular system and occurs mostly secondary to intracerebral haemorrhage (ICH) in adults. Hydrocephalus is a severe complication of IVH that can serve as an independent predictor of increased mortality. In this mini-review, we focus on the mechanisms of hydrocephalus after adult IVH, including blood-clot blockage, barrier impairment, inflammation and blood components, and attempt to reconcile the current research findings into a unified framework. We expect our theoretical framework to help guide future clinical and basic research leading to improved monitoring and intervention for IVH and subsequent hydrocephalus.
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Affiliation(s)
- Yaoyao Bu
- Department of Neurology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Meiyuan Chen
- Department of Neurology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Ting Gao
- Department of Neurology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xiao Wang
- Department of Neurology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xuting Li
- Department of Neurology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Feng Gao
- Department of Neurology, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
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34
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Skjolding AD, Holst AV, Broholm H, Laursen H, Juhler M. Differences in distribution and regulation of astrocytic aquaporin-4 in human and rat hydrocephalic brain. Neuropathol Appl Neurobiol 2015; 39:179-91. [PMID: 22497211 DOI: 10.1111/j.1365-2990.2012.01275.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS Aquaporin-4 (AQP4) is the most abundant cellular water channel in brain and could be a molecular basis for a cerebrospinal fluid absorption route additional to the arachnoid villi. In the search for 'alternative' cerebrospinal fluid absorption pathways it is important to compare experimental findings with human pathophysiology. This study compares expression of AQP4 in hydrocephalic human brain with human controls and hydrocephalic rat brain. METHODS Cortical biopsies from patients with chronic hydrocephalus (n = 29) were sampled secondary to planned surgical intervention. AQP4 in human hydrocephalic cortex relative to controls was quantified by Western blotting (n = 28). A second biopsy (n = 13) was processed for immunohistochemistry [glial fibrillary acidic protein (GFAP), CD68, CD34 and AQP4] and double immunofluorescence (AQP4 + GFAP and AQP4 + CD34). Brain tissue from human controls and kaolin-induced hydrocephalic rats was processed in parallel. Immunohistochemistry and immunofluorescence were assessed qualitatively. RESULTS Western blotting showed that AQP4 abundance was significantly increased (P < 0.05) in hydrocephalic human brain compared with controls. AQP4 immunoreactivity was present in both white and grey matter. In human brain (hydrocephalic and controls) AQP4 immunoreactivity was found on the entire astrocyte membrane, unlike hydrocephalic rat brain where pronounced endfeet polarization was present. Endothelial AQP4 immunoreactivity was not observed. CONCLUSIONS This study shows a significant increase in astrocytic AQP4 in human hydrocephalic cortex compared with control. Cell type specific expression in astrocytes is conserved between rat and human, although differences of expression in specific membrane domains are seen. This study addresses direct translational aspects from rat to human, hereby emphasizing the relevance and use of models in hydrocephalus research.
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Affiliation(s)
- A D Skjolding
- University Clinic of NeurosurgeryLaboratory of Neuropathology, Copenhagen University Hospital, RigshopitaletDepartment of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - A V Holst
- University Clinic of NeurosurgeryLaboratory of Neuropathology, Copenhagen University Hospital, RigshopitaletDepartment of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - H Broholm
- University Clinic of NeurosurgeryLaboratory of Neuropathology, Copenhagen University Hospital, RigshopitaletDepartment of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - H Laursen
- University Clinic of NeurosurgeryLaboratory of Neuropathology, Copenhagen University Hospital, RigshopitaletDepartment of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - M Juhler
- University Clinic of NeurosurgeryLaboratory of Neuropathology, Copenhagen University Hospital, RigshopitaletDepartment of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Oklinski MK, Choi HJ, Kwon TH. Peripheral nerve injury induces aquaporin-4 expression and astrocytic enlargement in spinal cord. Neuroscience 2015; 311:138-52. [PMID: 26480815 DOI: 10.1016/j.neuroscience.2015.10.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Revised: 09/22/2015] [Accepted: 10/13/2015] [Indexed: 12/15/2022]
Abstract
Aquaporin-4 (AQP4), a water channel protein, is expressed mainly in the perivascular end-feet of astrocytes in the brain and spinal cord. Dysregulation of AQP4 is critically associated with abnormal water transport in the astrocytes. We aimed to examine whether peripheral nerve injury (PNI) could induce the changes of AQP4 expression and astrocytic morphology in the spinal cord. Two different PNI models [partial sciatic nerve transection (PST) and chronic constriction injury (CCI)] were established on the left sciatic nerve in Sprague-Dawley rats, which decreased the pain withdrawal threshold in the ipsilateral hind paws. Both PNI models were associated with a persistent up-regulation of AQP4 in the ipsilateral dorsal horn at the lower lumbar region over 3 weeks, despite an absence of direct injury to the spinal cord. Three-dimensional reconstruction of astrocytes was made and morphometric analysis was done. Up-regulation of AQP4 was accompanied by a significant increase in the length and volume of astrocytic processes and the number of branch points. The most prominent changes were present in the distal processes of the astrocytes and the changes were maintained throughout the whole experimental period. Extravasation of systemically administered tracers Evans Blue and sodium fluorescein was not seen in both models. Taken together, PNI was associated with a long-lasting AQP4 up-regulation and enlargement of astrocytic processes in the spinal cord in rats, both of which were not related to the disruption of blood-spinal cord barrier. The findings could provide novel insights on the understanding of pathophysiology of spinal cords after PNI.
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Affiliation(s)
- M K Oklinski
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu 41944, South Korea
| | - H-J Choi
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu 41944, South Korea
| | - T-H Kwon
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu 41944, South Korea.
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Blasco E, Martorell J, De la Fuente C, Pumarola M. Immunohistochemical Study of Aquaporins in an African Grey Parrot (Psittacus erithacus) With Hydrocephalus. J Avian Med Surg 2014; 28:309-15. [PMID: 25843469 DOI: 10.1647/2013-059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A 5-month-old African grey parrot (Psittacus erithacus) was examined after 3 weeks of weakness, ataxia, mental depression, and seizures. Results of a complete blood cell count and plasma biochemical analysis were unremarkable. Magnetic resonance imaging revealed a severe bilateral hydrocephalus. The bird failed to improve with supportive care, and the owner requested euthanasia. Necropsy findings were severe bilateral hydrocephalus with no evidence of cerebrospinal fluid obstruction. Histologic examination of the brain revealed microspongiosis, edema, gliosis, and neuronal chromatolysis of surrounding periventricular tissue. Aquaporins (AQP) and astrocytes were examined to elucidate the participation of these water channel proteins and glial cells in the pathophysiology and resolution of hydrocephalus. Results showed AQP4 and glial fibrillary acidic protein were overexpressed, especially near the ventricles, but expression of AQP1 was decreased. This is the first report, to our knowledge, of AQP immunolabeling in hydrocephalus in avain species.
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Sveinsdottir S, Gram M, Cinthio M, Sveinsdottir K, Mörgelin M, Ley D. Altered expression of aquaporin 1 and 5 in the choroid plexus following preterm intraventricular hemorrhage. Dev Neurosci 2014; 36:542-51. [PMID: 25342576 DOI: 10.1159/000366058] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 07/21/2014] [Indexed: 11/19/2022] Open
Abstract
Intraventricular hemorrhage (IVH) with posthemorrhagic ventricular dilatation (PHVD) is a common cause of hydrocephalus in infants. Dysregulation of cerebrospinal fluid (CSF) production by the choroid plexus may contribute to the development of PHVD. The aquaporins (AQPs), transmural water transporting proteins, are believed to contribute to CSF production. The aim of the study was to characterize the expression and localization of AQP1, 4 and 5 in the choroid plexus following preterm IVH. Using a preterm rabbit pup model, the mRNA expression, protein level and localization of AQP1, 4 and 5 were investigated in the choroid plexus at 24 and 72 h following IVH with PHVD. Further, AQP1, 4 and 5 expression were characterized in primary human plexus epithelial cells exposed to CSF from preterm human infants with IVH and to hemoglobin metabolites. IVH with PHVD in the immature brain caused a downregulation of AQP1 mRNA, the key AQP in CSF production, but an upregulation of AQP1 protein level with apical epithelial cell localization. Notably, AQP5 was expressed in the choroid plexus with upregulated mRNA expression and protein levels during PHVD with apical epithelial cell localization. Analysis of human choroid plexus epithelial cells in vitro, following exposure to posthemorrhagic CSF and to hemin, displayed results concordant with those observed in vivo, i.e. downregulation of AQP1 mRNA and upregulation of AQP5 mRNA expression. AQP4 was neither detectable in vivo nor in vitro. The changes observed in AQP1 and AQP5 expression in the choroid plexus suggest an adaptive response following IVH with possible functional implications for the development of PHVD.
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Overactivation of corticotropin-releasing factor receptor type 1 and aquaporin-4 by hypoxia induces cerebral edema. Proc Natl Acad Sci U S A 2014; 111:13199-204. [PMID: 25146699 DOI: 10.1073/pnas.1404493111] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cerebral edema is a potentially life-threatening illness, but knowledge of its underlying mechanisms is limited. Here we report that hypobaric hypoxia induces rat cerebral edema and neuronal apoptosis and increases the expression of corticotrophin releasing factor (CRF), CRF receptor type 1 (CRFR1), aquaporin-4 (AQP4), and endothelin-1 (ET-1) in the cortex. These effects, except for the increased expression of CRF itself, could all be blocked by pretreatment with an antagonist of the CRF receptor CRFR1. We also show that, in cultured primary astrocytes: (i) both CRFR1 and AQP4 are expressed; (ii) exogenous CRF, acting through CRFR1, triggers signaling of cAMP/PKA, intracellular Ca(2+), and PKCε; and (iii) the up-regulated cAMP/PKA signaling contributes to the phosphorylation and expression of AQP4 to enhance water influx into astrocytes and produces an up-regulation of ET-1 expression. Finally, using CHO cells transfected with CRFR1(+) and AQP4(+), we show that transfected CRFR1(+) contributes to edema via transfected AQP4(+). In conclusion, hypoxia triggers cortical release of CRF, which acts on CRFR1 to trigger signaling of cAMP/PKA in cortical astrocytes, leading to activation of AQP4 and cerebral edema.
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Akiguchi I, Shirakashi Y, Budka H, Watanabe Y, Watanabe T, Shiino A, Ogita M, Kawamoto Y, Jungwirth S, Krampla W, Fischer P. Disproportionate subarachnoid space hydrocephalus-outcome and perivascular space. Ann Clin Transl Neurol 2014; 1:562-9. [PMID: 25356428 PMCID: PMC4184559 DOI: 10.1002/acn3.87] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 07/28/2014] [Accepted: 07/29/2014] [Indexed: 11/21/2022] Open
Abstract
Objective We sought to identify the prevalence of MRI features of disproportionately enlarged subarachnoid space hydrocephalus in possible idiopathic normal pressure hydrocephalus (DESH-iNPH) and to describe the clinico-radiological features and outcomes of a community-based investigation (The Vienna Trans-Danube Aging study). Methods Of the 697 inhabitants (all 75 years old), 503 completed extensive neurological examinations at baseline and were followed up every 30 months thereafter with MRIs, mini-mental state examination (MMSE), and the Unified Parkinson Disease Rating Scale-Motor Section (UPDRSM). The DESH-iNPH participant data were compared with the data from participants with Evans index ratios >0.3 (ex vacuo hydrocephalus), cerebral small-vessel diseases, and normal MRIs. The widening of perivascular space was also evaluated by MRI in these groups. Results Eight participants with DESH-iNPH (1.6%) and 76 with ex vacuo hydrocephalus (16.1%) at baseline were identified. The mean MMSE in DESH-iNPH, ex vacuo hydrocephalus, and normal MRIs was 26.4, 27.9, and 28.3, respectively, and the mean UPDRSM was 9.75, 2.96, and 1.87, respectively. After a 90-month follow-up, the mortality rates for DESH-iNPH, ex vacuo hydrocephalus, and normal MRIs were 25.0%, 21.3%, and 10.9%, respectively. The perivascular-space widening scores were significantly smaller in the DESH-iNPH cases, particularly at the centrum semiovale, compared to cerebral small-vessel disease and ex vacuo hydrocephalus cases. Interpretation The prevalence of DESH-iNPH was 1.6% for participants aged 75 years and revealed significantly lower MMSE and higher UPDRSM scores compared to the ex vacuo hydrocephalus and controls. Moreover, it is suggested that perivascular-space narrowing is a morphological and pathophysiological marker of DESH-iNPH.
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Affiliation(s)
- Ichiro Akiguchi
- Center of Neurological and Cerebrovascular Diseases, Takeda Hospital Kyoto, Japan ; Department of Health Science, Kyoto Koka Women's University Kyoto, Japan
| | - Yoshitomo Shirakashi
- Center of Neurological and Cerebrovascular Diseases, Takeda Hospital Kyoto, Japan ; Biomedical MR Science Center, Shiga University of Medical Science Otsu, Japan
| | - Herbert Budka
- Institute of Neurology, Medical University of Vienna Vienna, Austria
| | - Yuko Watanabe
- Center of Neurological and Cerebrovascular Diseases, Takeda Hospital Kyoto, Japan
| | - Toshiyuki Watanabe
- Department of Health Science, Kyoto Koka Women's University Kyoto, Japan ; Biomedical MR Science Center, Shiga University of Medical Science Otsu, Japan
| | - Akihiko Shiino
- Department of Health Science, Kyoto Koka Women's University Kyoto, Japan ; Biomedical MR Science Center, Shiga University of Medical Science Otsu, Japan
| | - Mihoko Ogita
- Department of Health Science, Kyoto Koka Women's University Kyoto, Japan
| | - Yasuhiro Kawamoto
- Department of Health Science, Kyoto Koka Women's University Kyoto, Japan
| | | | - Wolfgang Krampla
- Ludwig Boltzmann Institute of Digital Radiography and Intervention Radiology Vienna, Austria
| | - Peter Fischer
- Ludwig Boltzmann Institute of Aging Research Vienna, Austria ; Psychiatric Department, Danube Hospital Vienna, Austria
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Jiménez AJ, Domínguez-Pinos MD, Guerra MM, Fernández-Llebrez P, Pérez-Fígares JM. Structure and function of the ependymal barrier and diseases associated with ependyma disruption. Tissue Barriers 2014; 2:e28426. [PMID: 25045600 PMCID: PMC4091052 DOI: 10.4161/tisb.28426] [Citation(s) in RCA: 132] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 03/03/2014] [Accepted: 03/03/2014] [Indexed: 12/20/2022] Open
Abstract
The neuroepithelium is a germinal epithelium containing progenitor cells that produce almost all of the central nervous system cells, including the ependyma. The neuroepithelium and ependyma constitute barriers containing polarized cells covering the embryonic or mature brain ventricles, respectively; therefore, they separate the cerebrospinal fluid that fills cavities from the developing or mature brain parenchyma. As barriers, the neuroepithelium and ependyma play key roles in the central nervous system development processes and physiology. These roles depend on mechanisms related to cell polarity, sensory primary cilia, motile cilia, tight junctions, adherens junctions and gap junctions, machinery for endocytosis and molecule secretion, and water channels. Here, the role of both barriers related to the development of diseases, such as neural tube defects, ciliary dyskinesia, and hydrocephalus, is reviewed.
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Affiliation(s)
- Antonio J Jiménez
- Department of Cell Biology, Genetics, and Physiology; University of Malaga; Malaga, Spain
| | | | - María M Guerra
- Institute of Anatomy, Histology, and Pathology; Austral University of Chile; Valdivia, Chile
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Abstract
Aquaporin-4 (AQP4) is one of the most abundant molecules in the brain and is particularly prevalent in astrocytic membranes at the blood-brain and brain-liquor interfaces. While AQP4 has been implicated in a number of pathophysiological processes, its role in brain physiology has remained elusive. Only recently has evidence accumulated to suggest that AQP4 is involved in such diverse functions as regulation of extracellular space volume, potassium buffering, cerebrospinal fluid circulation, interstitial fluid resorption, waste clearance, neuroinflammation, osmosensation, cell migration, and Ca(2+) signaling. AQP4 is also required for normal function of the retina, inner ear, and olfactory system. A review will be provided of the physiological roles of AQP4 in brain and of the growing list of data that emphasize the polarized nature of astrocytes.
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Strahle J, Garton HJL, Maher CO, Muraszko KM, Keep RF, Xi G. Mechanisms of hydrocephalus after neonatal and adult intraventricular hemorrhage. Transl Stroke Res 2013; 3:25-38. [PMID: 23976902 DOI: 10.1007/s12975-012-0182-9] [Citation(s) in RCA: 145] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Intraventricular hemorrhage (IVH) is a cause of significant morbidity and mortality and is an independent predictor of a worse outcome in intracerebral hemorrhage (ICH) and germinal matrix hemorrhage (GMH). IVH may result in both injuries to the brain as well as hydrocephalus. This paper reviews evidence on the mechanisms and potential treatments for IVH-induced hydrocephalus. One frequently cited theory to explain hydrocephalus after IVH involves obliteration of the arachnoid villi by microthrombi with subsequent inflammation and fibrosis causing CSF outflow obstruction. Although there is some evidence to support this theory, there may be other mechanisms involved, which contribute to the development of hydrocephalus. It is also unclear whether the causes of acute and chronic hydrocephalus after hemorrhage occur via different mechanisms; mechanical obstruction by blood in the former, and inflammation and fibrosis in the latter. Management of IVH and strategies for prevention of brain injury and hydrocephalus are areas requiring further study. A better understanding of the pathogenesis of hydrocephalus after IVH, may lead to improved strategies to prevent and treat post-hemorrhagic hydrocephalus.
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Affiliation(s)
- Jennifer Strahle
- Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan, USA
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Nabiuni M, Nazari Z, Safaeinejad Z, Delfan B, Miyan JA. Curcumin downregulates aquaporin-1 expression in cultured rat choroid plexus cells. J Med Food 2013; 16:504-10. [PMID: 23735000 DOI: 10.1089/jmf.2012.0208] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Aquaporin-1 (AQP1) is a water channel that is highly expressed on the apical side of the choroid plexus epithelium (CP) and thought to be one of the major pathways for the high water permeability of this structure. Blockade of AQP1 in the CP reduce the production of cerebrospinal fluid (CSF). Downregulation of AQP1 might be protective against some neurological disorders correlated with increased intracranial pressure and/or poor drainage of CSF. Curcumin, the major constituent of the rhizome of Curcuma longa, has been shown to inhibit potassium channels, Na⁺-K⁺ ATPase, as well as AQP3 in some cells. We therefore speculated that curcumin might be a useful tool to inhibit and/or decrease AQP1, and thus might be useful in the regulation of CSF production in pathophysiological conditions, including traumatic brain injury, hydrocephalus, stroke, systemic hyponatremia, acute cerebral edema, and hypertension. Choroidal epithelial cells of the lateral ventricle of Wistar rats were isolated and grown in in-vitro cultures for 24 h. Curcumin was then added to the medium at different concentrations, and the cell viability tested by the (3,4,5-dimethylthiazol-2-yl)-2-5-diphenyltetrazolium bromide assay. Additional wells of cells were tested for AQP1 protein expression using immunocytochemistry, immunoblotting, and flow cytometry. Our results showed that curcumin treatment decreases AQP1 expression in rat choroid epithelium cells in a dose-dependent manner. We conclude that curcumin may be a useful tool to regulate CSF production in pathophysiological conditions such as hydrocephalus, systemic hyponatremia, hypertension, and other neurological conditions.
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Affiliation(s)
- Mohammad Nabiuni
- Department of Cell and Molecular Biology, Faculty of Biological Sciences, Kharazmi University-TMU, Tehran, Iran
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Castañeyra-Ruiz L, González-Marrero I, González-Toledo JM, Castañeyra-Ruiz A, de Paz-Carmona H, Castañeyra-Perdomo A, Carmona-Calero EM. Aquaporin-4 expression in the cerebrospinal fluid in congenital human hydrocephalus. Fluids Barriers CNS 2013; 10:18. [PMID: 23659378 PMCID: PMC3651869 DOI: 10.1186/2045-8118-10-18] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2012] [Accepted: 04/25/2013] [Indexed: 11/21/2022] Open
Abstract
Background Aquaporin-4 (AQP4) is a water channel mainly located in the ventricular ependymal cells (brain-CSF barrier), the sub-ependymal glia, glia limitans and in end-feet of astrocytes in at the blood–brain barrier (BBB). Methods In the present work, the expression of AQP4 in the cerebrospinal fluid (CSF) in control and congenital human hydrocephalus infants (obstructive and communicating), was analysed by Western-blot and enzyme immunoassay (ELISA). Results AQP4 was found to be high compared to the control in the CSF in congenital hydrocephalus patients. Western-blot showed higher values for AQP4 than controls in communicating hydrocephalus (communicating: 38.3%, control: 6.9% p < 0.05) although the increase was not significant in obstructive hydrocephalus (obstructive: 14.7%). The AQP4 quantification by ELISA also showed that, the mean concentration of AQP4 in CSF was significantly higher in communicating hydrocephalus (communicating: 11.32 ± 0.69 ng/ml, control: 8.61 ± 0.31 ng/ml; p < 0.05). However, there was no increase over control in obstructive hydrocephalus (obstructive: 8.65 ± 0.80 ng/ml). Conclusions AQP4 has a modulatory effect on ependyma stability and acts in CSF production and reabsorption. Therefore, the increase of AQP4 in the CSF in congenital hydrocephalus could be due to the fact that AQP4 passes from the parenchyma to the CSF and this AQP4 movement may be a consequence of ependyma denudation.
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Affiliation(s)
- Leandro Castañeyra-Ruiz
- Departamento de Anatomía, Facultad de Medicina, Universidad de La Laguna, La Laguna, Tenerife, Canary Island, Spain.
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Roales-Buján R, Páez P, Guerra M, Rodríguez S, Vío K, Ho-Plagaro A, García-Bonilla M, Rodríguez-Pérez LM, Domínguez-Pinos MD, Rodríguez EM, Pérez-Fígares JM, Jiménez AJ. Astrocytes acquire morphological and functional characteristics of ependymal cells following disruption of ependyma in hydrocephalus. Acta Neuropathol 2012; 124:531-46. [PMID: 22576081 PMCID: PMC3444707 DOI: 10.1007/s00401-012-0992-6] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 04/25/2012] [Accepted: 04/27/2012] [Indexed: 01/10/2023]
Abstract
Hydrocephalic hyh mutant mice undergo a programmed loss of the neuroepithelium/ependyma followed by a reaction of periventricular astrocytes, which form a new cell layer covering the denuded ventricular surface. We present a comparative morphological and functional study of the newly formed layer of astrocytes and the multiciliated ependyma of hyh mice. Transmission electron microscopy, immunocytochemistry for junction proteins (N-cadherin, connexin 43) and proteins involved in permeability (aquaporin 4) and endocytosis (caveolin-1, EEA1) were used. Horseradish peroxidase (HRP) and lanthanum nitrate were used to trace the intracellular and paracellular transport routes. The astrocyte layer shares several cytological features with the normal multiciliated ependyma, such as numerous microvilli projected into the ventricle, extensive cell–cell interdigitations and connexin 43-based gap junctions, suggesting that these astrocytes are coupled to play an unknown function as a cell layer. The ependyma and the astrocyte layers also share transport properties: (1) high expression of aquaporin 4, caveolin-1 and the endosome marker EEA1; (2) internalization into endocytic vesicles and early endosomes of HRP injected into the ventricle; (3) and a similar paracellular route of molecules moving between CSF, the subependymal neuropile and the pericapillary space, as shown by lanthanum nitrate and HRP. A parallel analysis performed in human hydrocephalic foetuses indicated that a similar phenomenon would occur in humans. We suggest that in foetal-onset hydrocephalus, the astrocyte assembly at the denuded ventricular walls functions as a CSF–brain barrier involved in water and solute transport, thus contributing to re-establish lost functions at the brain parenchyma–CSF interphase.
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Affiliation(s)
- Ruth Roales-Buján
- Departamento de Biología Celular, Genética y Fisiología, Universidad de Málaga, Campus Universitario de Teatinos, 29071 Málaga, Spain
| | - Patricia Páez
- Departamento de Biología Celular, Genética y Fisiología, Universidad de Málaga, Campus Universitario de Teatinos, 29071 Málaga, Spain
| | - Montserrat Guerra
- Instituto de Anatomía, Histología y Patología, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile
| | - Sara Rodríguez
- Instituto de Anatomía, Histología y Patología, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile
| | - Karin Vío
- Instituto de Anatomía, Histología y Patología, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile
| | - Ailec Ho-Plagaro
- Departamento de Biología Celular, Genética y Fisiología, Universidad de Málaga, Campus Universitario de Teatinos, 29071 Málaga, Spain
| | - María García-Bonilla
- Departamento de Biología Celular, Genética y Fisiología, Universidad de Málaga, Campus Universitario de Teatinos, 29071 Málaga, Spain
| | - Luis-Manuel Rodríguez-Pérez
- Departamento de Biología Celular, Genética y Fisiología, Universidad de Málaga, Campus Universitario de Teatinos, 29071 Málaga, Spain
| | - María-Dolores Domínguez-Pinos
- Departamento de Biología Celular, Genética y Fisiología, Universidad de Málaga, Campus Universitario de Teatinos, 29071 Málaga, Spain
| | - Esteban-Martín Rodríguez
- Instituto de Anatomía, Histología y Patología, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile
| | - José-Manuel Pérez-Fígares
- Departamento de Biología Celular, Genética y Fisiología, Universidad de Málaga, Campus Universitario de Teatinos, 29071 Málaga, Spain
| | - Antonio-Jesús Jiménez
- Departamento de Biología Celular, Genética y Fisiología, Universidad de Málaga, Campus Universitario de Teatinos, 29071 Málaga, Spain
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Reactive gliosis and neuroinflammation in rats with communicating hydrocephalus. Neuroscience 2012; 218:317-25. [DOI: 10.1016/j.neuroscience.2012.05.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Revised: 04/05/2012] [Accepted: 05/03/2012] [Indexed: 02/07/2023]
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Abstract
INTRODUCTION Aquaporins (AQPs) are membrane proteins that facilitate water and small solute movement in tissues. Hydrocephalus is the major central nervous system disorder associated with defective cerebrospinal fluid turnover. Aquaporin-4 (AQP4) is a water channel located mainly at the blood-brain barrier (BBB) and blood-cerebrospinal fluid (CSF) interfaces and is associated with the elimination of cerebral edema via these routes. The aim of this study is to review the pertinent literature concerning the role of AQP4 in the pathophysiology of hydrocephalus. METHODS We performed a MEDLINE search using the terms aquaporin AND hydrocephalus. The results of the search were further refined to exclude studies not related to aquaporin-4. RESULTS Six studies were identified. All studies utilized an animal model such as AQP4-knockout mice, H-Tx rats, and kaolin and L-α-lysophosphatidylcholine (LPC) stearoyl injection models of hydrocephalus. Most studies indicate that there is an up-regulation of AQP4 expression at the BBB and blood-CSF interfaces in cases of hydrocephalus. One study, reported sporadic cases of obstructive hydrocephalus in a subgroup of AQP4-knockout mice. CONCLUSIONS Few publications have studied the association between aquaporins and hydrocephalus. Currently, all the existing studies rely on animal models. An adaptive and protective role of AQP4 to increase the resolution of the "hydrocephalic" edema at the BBB and blood-CSF interfaces is proposed in the pathophysiology of hydrocephalus. Further research is needed to clarify if this association exists in humans.
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Kalani MYS, Filippidis AS, Rekate HL. Hydrocephalus and aquaporins: the role of aquaporin-1. ACTA NEUROCHIRURGICA. SUPPLEMENT 2012; 113:51-4. [PMID: 22116423 DOI: 10.1007/978-3-7091-0923-6_11] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
INTRODUCTION Aquaporins (AQPs) are membrane proteins that facilitate water and small solute movement in tissues. Hydrocephalus is a major central nervous system disorder associated with defective cerebrospinal fluid (CSF) turnover. Aquaporin-1 (AQP1) is a water channel located mainly at the choroid plexus epithelium and plays an active role in CSF production. The aim of this study is to review the pertinent literature concerning the role of aquaporin-1 in the pathophysiology of hydrocephalus. METHODS We performed a MEDLINE search using the terms aquaporin AND hydrocephalus. The results of the search were further refined to exclude studies not related to aquaporin-1. RESULTS Five studies were identified. Three of these studies utilized an animal model, while only two studies referred to a few human cases of hydrocephalus. Most of the studies indicate that there is a down-regulation of AQP1 expression in choroid plexus in models of hydrocephalus. A small series of human choroid plexus tumors showed that AQP1 expression is up-regulated. In cases of human choroid plexus tumors, there are indications that AQP1 may have alternative physiologic roles, but it is not clear whether this is associated with a specific type of hydrocephalus or the genetic burden of the tumor. CONCLUSION There has been a paucity of research on the link between aquaporins and hydrocephalus. Most studies have relied on animal models. An adaptive and protective role of AQP1 as a regulator of CSF production is proposed in the pathophysiology of hydrocephalus. Further research is needed to clarify if this association exists in humans.
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Affiliation(s)
- M Y S Kalani
- St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA
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Eskandari R, Harris CA, McAllister JP. Reactive astrocytosis in feline neonatal hydrocephalus: acute, chronic, and shunt-induced changes. Childs Nerv Syst 2011; 27:2067-76. [PMID: 21847645 DOI: 10.1007/s00381-011-1552-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 07/29/2011] [Indexed: 10/17/2022]
Abstract
PURPOSE Reactive astrocytosis has been implicated in injury and recovery patterns associated with hydrocephalus. To investigate temporal changes in astrogliosis during the early progression of hydrocephalus, after shunting, and after long-term ventriculomegaly, glial fibrillary protein (GFAP) levels were analyzed in a feline model. METHODS Obstructive hydrocephalus was induced in 10-day-old kittens by intracisternal injections of 25% kaolin. Acute non-shunted animals were killed 15 days post-kaolin injection to represent the pre-shunt condition. Shunt-treated animals received ventriculoperitoneal shunts 15 days post-injection and were killed 10 or 60 days later to represent short- and long-term recovery periods. Chronic untreated animals had Ommaya reservoirs implanted 15 days post-kaolin, which were tapped intermittently until they were killed 60 days later. Ventriculomegaly was monitored by neuroimaging before and after shunting and at death. RNA and total protein from primary visual cortex were analyzed by Northern and Western blotting. RESULTS GFAP RNA and protein levels for acute and chronic non-shunted hydrocephalic animals were 77% and 247% (p < 0.01) and 659% (p < 0.05) and 871% (p < 0.05) higher than controls, respectively. Shunted animals with short-term recovery demonstrated a mismatch in GFAP levels, with RNA expression decreasing 26% and protein increasing 335% (p < 0.01). Shunted animals with a long-term recovery exhibited GFAP RNA and protein levels 201% and 357% above normal, respectively. CONCLUSIONS These results indicate that a reactive astrocytic response continues to rise dramatically in chronic hydrocephalus, suggesting ongoing gliosis and potential damage. Shunting partially ameliorates the continuation of astrogliosis, but does not completely reverse this inflammatory reaction even after a long recovery.
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Affiliation(s)
- Ramin Eskandari
- Division of Pediatric Neurosurgery, Department of Neurosurgery, University of Utah, 175 North Medical Drive, Salt Lake City, UT 84132, USA
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Paul L, Madan M, Rammling M, Chigurupati S, Chan SL, Pattisapu JV. Expression of aquaporin 1 and 4 in a congenital hydrocephalus rat model. Neurosurgery 2011; 68:462-73. [PMID: 21135737 DOI: 10.1227/neu.0b013e3182011860] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Hydrocephalus occurs because of an imbalance of bulk fluid flow in the brain, and aquaporins (AQPs) play pivotal roles in cerebral water movement as essential mediators during edema and fluid accumulation. AQP1 is a water channel found in the choroid plexus (CP), and AQP4 is expressed at the brain-CSF interfaces and astrocytic end feet; excessive fluid accumulation may involve expression of changes in these AQPs during various stages of hydrocephalus. OBJECTIVE To determine the alterations of CP AQP1 expression in congenital hydrocephalus; detect hydrocephalus-induced AQP1 expression in the cortical parenchyma, ependyma, and pia mater of hydrocephalic animals; and evaluate AQP4 expression in congenital hydrocephalus through progressive stages of the condition. METHODS We evaluated differential expression of AQPs 1 and 4 in the congenital hydrocephalus Texas rat at postnatal days 5, 10, and 26 in isolated CP and cortex by enzyme-linked immunosorbent assay, Western blot, quantitative reverse transcriptase polymerase chain reaction, and immunohistochemistry. RESULTS The CP exhibited a 34% decrease in AQP1 expression in young hydrocephalic pups (postnatal days 5 and 10), which became normal (postnatal day 26) just before death. With advancing hydrocephalus, expression of AQPs 1 and 4 increased at the brain-CSF interfaces; AQP1 was localized to the endothelium of cortical capillaries with increased AQP4 expression in surrounding astrocytes end feet. AQP1 expression level was increased in the pia mater, with prominent AQP4 expression in the subpial layers. Subependymal capillaries expressed AQP1 in the endothelium, with increasing AQP4 expression in surrounding astrocytes. Hydrocephalic animals (postnatal day 26) had significant nonendothelial (CD34) AQP1 expression in the septal nucleus of the basal forebrain, an area affected by increased intracranial pressure. CONCLUSION Biphasic AQP1 expression in the CP with increased AQPs 1 and 4 at the brain-fluid interfaces may indicate compensatory mechanisms to regulate choroidal cerebrospinal fluid secretion and increase parenchymal fluid absorption in the high-pressure hydrocephalic condition.
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Affiliation(s)
- Leena Paul
- Burnett School of Biomedical Science, College of Medicine, University of Central Florida Orlando, Florida, USA.
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