“The glymphatic system is a recently discovered macroscopic waste clearance system that utilizes a unique system of perivascular tunnels, formed by astroglial cells, to promote efficient elimination of soluble proteins and metabolites from the central nervous system. besides waste elimination, the glymphatic system also facilitates brain-wide distribution of several compounds, including glucose, lipids, amino acids, growth factors, and neuromodulators. intriguingly, the glymphatic system function mainly during sleep and is largely disengaged during wakefulness. the biological need for sleep across all species may therefore reflect that the brain must enter a state of activity that enables elimination of potentially neurotoxic waste products, including β-amyloid. since the concept of the glymphatic system is relatively new, we will here review its basic structural elements, organization, regulation, and functions. we will also discuss recent studies indicating that glymphatic function is suppressed in various diseases and that failure of glymphatic function in turn might contribute to pathology in neurodegenerative disorders, traumatic brain injury and stroke.”

“Glymphatic system is newly discovered pseudolymphatic system in brain and it plays an important role in the removal of interstitial metabolic waste products. we discuss and review the role of glymphatic system in neurological diseases, especially focus on the potential of mri modelling and its associated challenges to obtain useful new information related to understand the glymphatic system dynamics, pathways, and provide quantitative maps for diagnosis, monitoring and prognosis of the disease. the non-invasive nature of mri might more readily help with translation of glymphatic measurements from the laboratory to the clinic.”

“The glymphatic system creates a network of perivascular channels. it is made of astroglia cells, whose perikaryon extensions strongly express aquaporin-4 water channels (aqp4). the pathways of the glymphatic system ensure the transport of nutrients, including glucose, lipids, amino acids, neurotransmitters, antigens, and immune cells, as well as exchange of information via afferent and efferent immune pathways. within the glymphatic system, convective exchange of cerebrospinal fluid (csf) and interstitial fluid (isf) components takes place, through aquaporin-4 water channels that facilitate fluid exchange. the proper functioning of the glymphatic system allows elimination and reabsorption of solutes, metabolites, pursuit of water and ionic balance, transport of lipid signaling molecules, regulation of intracranial pressure, cerebrospinal fluid pressure, and interstitial fluid pressure. the functions of the glymphatic system are primarily affected by the influence of the sympathetic and parasympathetic innervation, sleep and wakefulness cycle, the aging process, genetic factors, and body posture. now, the glymphatic system shows weak activity during wakefulness, while its activity increases dramatically during sleep and the state of anesthesia. changes occurring with age begin a number of factors that impair the function of the glymphatic system pathways. dysfunction of the glymphatic pathways causes the aggregation of incorrectly formed proteins that underlie the development of neurodegenerative diseases. harmful protein aggregates cause prolonged inflammation. all pathologies occurring within the central nervous system (cns), both neurodegenerative diseases and injuries, disrupt the drainage of glymphatic pathways, which are important efflux of interstitial substances and byproducts of cns metabolism.”

“The glymphatic concept along with the discovery of meningeal lymphatic vessels have, in recent years, highlighted that fluid is directionally transported within the central nervous system (cns). imaging studies, as well as manipulations of fluid transport, point to a key role of the glymphatic–lymphatic system in clearance of amyloid-β and other proteins. as such, the glymphatic–lymphatic system represents a new target in combating neurodegenerative diseases. not unexpectedly, introduction of a new plumbing system in the brain has stirred controversies. this opinion article will highlight what we know about the brain’s fluid transport systems, where experimental data are lacking, and what is still debated.”

“The glymphatic system is a fluid-transport system that accesses all regions of the brain. it facilitates the exchange of cerebrospinal fluid and interstitial fluid and clears waste from the metabolically active brain. astrocytic endfeet and their dense expression of the aquaporin-4 water channels promote fluid exchange between the perivascular spaces and the neuropil. cerebrospinal and interstitial fluids are together transported back to the vascular compartment by meningeal and cervical lymphatic vessels. multiple lines of work show that neurological diseases in general impair glymphatic fluid transport. insofar as the glymphatic system plays a pseudo-lymphatic role in the central nervous system, it is poised to play a role in neuroinflammation. in this review, we discuss how the association of the glymphatic system with the meningeal lymphatic vessel calls for a renewal of established concepts on the cns as an immune-privileged site. we also discuss potential approaches to target the glymphatic system to combat neuroinflammation.”

“The glymphatic system and meningeal lymphatics have recently been characterized. glymphatic system is a glia-dependent system of perivascular channels, and it plays an important role in the removal of interstitial metabolic waste products. the meningeal lymphatics may be a key drainage route for cerebrospinal fluid into the peripheral blood, may contribute to inflammatory reaction and central nervous system (cns) immune surveillance. breakdowns and dysfunction of the glymphatic system and meningeal lymphatics play a crucial role in age-related brain changes, the pathogenesis of neurovascular and neurodegenerative diseases, as well as in brain injuries and tumors. this review discusses the relationship recently characterized meningeal lymphatic vessels with the glymphatic system, which provides perfusion of the cns with cerebrospinal and interstitial fluids. the review also presents the results of human studies concerning both the presence of meningeal lymphatics and the glymphatic system. a new understanding of how aging, medications, sleep and wake cycles, genetic predisposition, and even body posture affect the brain drainage system has not only changed the idea of brain fluid circulation but has also contributed to an understanding of the pathology and mechanisms of neurodegenerative diseases.”