Pseudotumor Cerebri and Glymphatic Dysfunction
In contrast to virtually all organ systems of the body, the central nervous system was until recently believed to be devoid of a lymphatic system. The demonstration of a complex system of paravascular channels formed by the endfeet of astroglial cells ultimately draining into the venous sinuses has...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2018-01-01
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| Series: | Frontiers in Neurology |
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| Online Access: | http://journal.frontiersin.org/article/10.3389/fneur.2017.00734/full |
| _version_ | 1811310146023849984 |
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| author | Marcio Luciano de Souza Bezerra Ana Carolina Andorinho de Freitas Ferreira Ricardo de Oliveira-Souza |
| author_facet | Marcio Luciano de Souza Bezerra Ana Carolina Andorinho de Freitas Ferreira Ricardo de Oliveira-Souza |
| author_sort | Marcio Luciano de Souza Bezerra |
| collection | DOAJ |
| description | In contrast to virtually all organ systems of the body, the central nervous system was until recently believed to be devoid of a lymphatic system. The demonstration of a complex system of paravascular channels formed by the endfeet of astroglial cells ultimately draining into the venous sinuses has radically changed this idea. The system is subsidized by the recirculation of cerebrospinal fluid (CSF) through the brain parenchyma along paravascular spaces (PVSs) and by exchanges with the interstitial fluid (IF). Aquaporin-4 channels are the chief transporters of water through these compartments. This article hypothesizes that glymphatic dysfunction is a major pathogenetic mechanism underpinning idiopathic intracranial hypertension (IIH). The rationale for the hypothesis springs from MRI studies, which have shown many signs related to IIH without evidence of overproduction of CSF. We propose that diffuse retention of IF is a direct consequence of an imbalance of glymphatic flow. This imbalance, in turn, may result from an augmented flow from the arterial PVS into the IF, by impaired outflow of the IF into the paravenous spaces, or both. Our hypothesis is supported by the facts that (i) visual loss, one of the main complications of IIH, is secondary to the impaired drainage of the optic nerve, a nerve richly surrounded by water channels and with a long extracranial course in its meningeal sheath; (ii) there is a high association between IIH and obesity, a condition related to paravascular inflammation and lymphatic disturbance, and (iii) glymphatic dysfunction has been related to the deposition of β-amyloid in Alzheimer’s disease. We conclude that the concept of glymphatic dysfunction provides a new perspective for understanding the pathophysiology of IIH; it may likewise entice the development of novel therapeutic approaches aiming at enhancing the flow between the CSF, the glymphatic system, and the dural sinuses. |
| first_indexed | 2024-04-13T09:54:21Z |
| format | Article |
| id | doaj.art-ff97a93814d6475dbd1ba0752aea6846 |
| institution | Directory Open Access Journal |
| issn | 1664-2295 |
| language | English |
| last_indexed | 2024-04-13T09:54:21Z |
| publishDate | 2018-01-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Neurology |
| spelling | doaj.art-ff97a93814d6475dbd1ba0752aea68462022-12-22T02:51:30ZengFrontiers Media S.A.Frontiers in Neurology1664-22952018-01-01810.3389/fneur.2017.00734287007Pseudotumor Cerebri and Glymphatic DysfunctionMarcio Luciano de Souza Bezerra0Ana Carolina Andorinho de Freitas Ferreira1Ricardo de Oliveira-Souza2Rio Sono Clinic, Rio de Janeiro, BrazilInstituto D’Or de Pesquisa e Ensino (IDOR), Rio de Janeiro, BrazilInstituto D’Or de Pesquisa e Ensino (IDOR), Rio de Janeiro, BrazilIn contrast to virtually all organ systems of the body, the central nervous system was until recently believed to be devoid of a lymphatic system. The demonstration of a complex system of paravascular channels formed by the endfeet of astroglial cells ultimately draining into the venous sinuses has radically changed this idea. The system is subsidized by the recirculation of cerebrospinal fluid (CSF) through the brain parenchyma along paravascular spaces (PVSs) and by exchanges with the interstitial fluid (IF). Aquaporin-4 channels are the chief transporters of water through these compartments. This article hypothesizes that glymphatic dysfunction is a major pathogenetic mechanism underpinning idiopathic intracranial hypertension (IIH). The rationale for the hypothesis springs from MRI studies, which have shown many signs related to IIH without evidence of overproduction of CSF. We propose that diffuse retention of IF is a direct consequence of an imbalance of glymphatic flow. This imbalance, in turn, may result from an augmented flow from the arterial PVS into the IF, by impaired outflow of the IF into the paravenous spaces, or both. Our hypothesis is supported by the facts that (i) visual loss, one of the main complications of IIH, is secondary to the impaired drainage of the optic nerve, a nerve richly surrounded by water channels and with a long extracranial course in its meningeal sheath; (ii) there is a high association between IIH and obesity, a condition related to paravascular inflammation and lymphatic disturbance, and (iii) glymphatic dysfunction has been related to the deposition of β-amyloid in Alzheimer’s disease. We conclude that the concept of glymphatic dysfunction provides a new perspective for understanding the pathophysiology of IIH; it may likewise entice the development of novel therapeutic approaches aiming at enhancing the flow between the CSF, the glymphatic system, and the dural sinuses.http://journal.frontiersin.org/article/10.3389/fneur.2017.00734/fullpseudotumor cerebriidiopathic intracranial hypertensionglymphatic systemparavascular spacesaquaporin-4cerebrospinal fluid |
| spellingShingle | Marcio Luciano de Souza Bezerra Ana Carolina Andorinho de Freitas Ferreira Ricardo de Oliveira-Souza Pseudotumor Cerebri and Glymphatic Dysfunction Frontiers in Neurology pseudotumor cerebri idiopathic intracranial hypertension glymphatic system paravascular spaces aquaporin-4 cerebrospinal fluid |
| title | Pseudotumor Cerebri and Glymphatic Dysfunction |
| title_full | Pseudotumor Cerebri and Glymphatic Dysfunction |
| title_fullStr | Pseudotumor Cerebri and Glymphatic Dysfunction |
| title_full_unstemmed | Pseudotumor Cerebri and Glymphatic Dysfunction |
| title_short | Pseudotumor Cerebri and Glymphatic Dysfunction |
| title_sort | pseudotumor cerebri and glymphatic dysfunction |
| topic | pseudotumor cerebri idiopathic intracranial hypertension glymphatic system paravascular spaces aquaporin-4 cerebrospinal fluid |
| url | http://journal.frontiersin.org/article/10.3389/fneur.2017.00734/full |
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