Fluid dynamics in aging-related dementias

Recent human and animal model experimental studies revealed novel pathways for fluid movement, immune cell trafficking and metabolic waste clearance in CNS. These studies raise the intriguing possibility that the newly discovered pathways, including the glymphatic system, lymphatic meningeal vessels and skull-brain communi-cation channels, are impaired in aging and neurovascular and neurodegenerative diseases associated with de-mentia, including Alzheimer's disease (AD) and AD-related dementia. We provide an overview of the glymphatic and dural meningeal lymphatic systems, review current methods and approaches used to study glymphatic flow in humans and animals, and discuss current evidence and controversies related to its role in CNS flow homeo-stasis under physiological and pathophysiological conditions. Non-invasive imaging approaches are needed to fully understand the mechanisms and pathways driving fluid movement in CNS and their roles across lifespan including healthy aging and aging-related dementia.

Automated summary

Recent studies have discovered new pathways for fluid movement, immune cell trafficking, and waste clearance in the central nervous system (CNS). These pathways, including the glymphatic system, meningeal lymphatic vessels, and skull-brain communication channels, may be impaired in aging and neurodegenerative diseases such as Alzheimer's disease. This review provides an overview of these systems, discusses current research methods, and explores the role of these pathways in CNS flow homeostasis under different conditions.