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DOI: 10.1055/s-0038-1667052
The Glymphatic System: A Review
O sistema glinfático: revisãoPublication History
28 January 2018
11 June 2018
Publication Date:
27 July 2018 (online)
![](https://www.thieme-connect.de/media/10.1055-s-00028832/201803/lookinside/thumbnails/10-1055-s-0038-1667052_1800009-1.jpg)
Abstract
The brain represents ∼ 2% of the adult body mass; conversely, it is responsible for 20% to 25% of the glucose and 20% of the oxygen consumption, receiving 15% of the cardiac output. This substantial metabolic rate is associated with a significant production of biological debris, which is potentially toxic. Therefore, a complex and efficient clearance system is required to prevent the accumulation of byproducts and ensure optimal function. However, until today, there is little knowledge about this topic. The glymphatic system, also known as perivascular pathway, is a recently described glial-dependent network that is responsible for the clearance of metabolites from the central nervous system (CNS), playing a role equivalent to the one played by the lymphatic vessels present in other organs. Studies have demonstrated that the glymphatic pathway has a paramount role in protein homeostasis, and that the malfunction of this system may be related to the development of neurodegenerative disorders such as Alzheimer disease and normal pressure hydrocephalus. They also showed that body posture, exercise and the state of consciousness influence the glymphatic transport. In this context, the understanding of this clearance system could not only clarify the pathophysiology of several diseases, but also contribute to future therapeutic interventions. In the present article, we will evaluate the glymphatic pathway, focusing on the factors that regulate its flow, as well as on its role in CNS physiology and in disease initiation and progression, including dementia, hydrocephalus, glaucoma and traumatic brain injury. Ultimately, this review also aims to encourage further research on novel therapeutic targets.
Resumo
O cérebro representa cerca de 2% da massa corporal de um adulto; contrariamente, é responsável por entre 20% e 25% do consumo de glicose, e 20% do consumo de oxigênio, respectivamente. Essa taxa metabólica substancial está associada à produção elevada de detritos biológicos, potencialmente tóxicos. Desse modo, um sistema de depuração complexo e eficiente faz-se necessário para prevenir o acúmulo de subprodutos e assegurar função ideal. No entanto, até os dias atuais, há pouco conhecimento acerca desse tópico. O sistema glinfático, também conhecido como via perivascular, é uma rede dependente de células da glia recentemente descrita, que é responsável pela depuração de metabólitos do sistema nervoso central (SNC), à semelhança dos vasos linfáticos presentes em outros órgãos. Estudos demonstraram que a via glinfática tem um papel fundamental na homeostase proteica, podendo sua disfunção ser associada ao desenvolvimento de transtornos neurodegenerativos, como a doença de Alzheimer e a hidrocefalia de pressão normal. Do mesmo modo, esses estudos demonstraram que a postura corporal, o exercício e o estado de consciência influenciam no transporte glinfático. Nesse contexto, o entendimento do sistema de depuração cerebral pode não só esclarecer a fisiopatologia de diversas doenças, como também contribuir para intervenções futuras. Neste artigo, revisaremos a via glinfática, focando em fatores que regulam o seu fluxo, e em seu papel na fisiologia do SNC e na iniciação e progressão de doenças, incluindo demência, hidrocefalia de pressão normal, glaucoma e traumatismo cranioencefálico. Por fim, esta revisão também visa estimular pesquisas sobre novos alvos terapêuticos.
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