2018 November ; 17(11): 1016–1024. | Martin Kaag Rasmussen#1, Humberto Mestre#2,3, and Maiken Nedergaard1,2,3,*
The glymphatic pathway, a recently identified fluid clearance system in the brain, facilitates the flow of cerebrospinal fluid (CSF) into the brain through perivascular spaces and then into the interstitial fluid (ISF). This pathway is primarily active during sleep, enhancing the clearance of harmful metabolites like amyloid β (Aβ). Dysfunctional glymphatic pathways have been observed in animal models of traumatic brain injury (TBI), Alzheimer's disease (AD), and micro-infarct disease, often associated with altered expression of aquaporin-4 (AQP4) water channels. Recent studies in humans using MRI and PET imaging techniques have confirmed the presence of a glymphatic pathway and its impairment in AD patients, particularly in the clearance of Aβ and tau tracers. The glymphatic pathway's role in various neurological disorders, including stroke and TBI, is also discussed, highlighting the potential for new diagnostic tools and therapeutic targets. Future research aims to further understand the factors influencing glymphatic function and its impact on brain health.The glymphatic pathway, a recently identified fluid clearance system in the brain, facilitates the flow of cerebrospinal fluid (CSF) into the brain through perivascular spaces and then into the interstitial fluid (ISF). This pathway is primarily active during sleep, enhancing the clearance of harmful metabolites like amyloid β (Aβ). Dysfunctional glymphatic pathways have been observed in animal models of traumatic brain injury (TBI), Alzheimer's disease (AD), and micro-infarct disease, often associated with altered expression of aquaporin-4 (AQP4) water channels. Recent studies in humans using MRI and PET imaging techniques have confirmed the presence of a glymphatic pathway and its impairment in AD patients, particularly in the clearance of Aβ and tau tracers. The glymphatic pathway's role in various neurological disorders, including stroke and TBI, is also discussed, highlighting the potential for new diagnostic tools and therapeutic targets. Future research aims to further understand the factors influencing glymphatic function and its impact on brain health.