The study investigates the functional aspects of meningeal lymphatics in aging and Alzheimer's disease (AD). Meningeal lymphatics are crucial for waste clearance from the central nervous system (CNS), draining macromolecules from the cerebrospinal fluid (CSF) and interstitial fluid (ISF) into cervical lymph nodes. Impairment of meningeal lymphatic function slows the influx of CSF macromolecules and the efflux of ISF macromolecules, leading to cognitive impairment. Treatment with vascular endothelial growth factor C (VEGF-C) enhances meningeal lymphatic drainage, improving brain perfusion and cognitive performance in aged mice. In AD transgenic mouse models, disruption of meningeal lymphatic vessels promotes amyloid deposition in the meninges and exacerbates parenchymal amyloid accumulation. These findings suggest that meningeal lymphatic dysfunction may contribute to age-associated cognitive decline and AD pathology, highlighting potential therapeutic targets for preventing or delaying neurological diseases.The study investigates the functional aspects of meningeal lymphatics in aging and Alzheimer's disease (AD). Meningeal lymphatics are crucial for waste clearance from the central nervous system (CNS), draining macromolecules from the cerebrospinal fluid (CSF) and interstitial fluid (ISF) into cervical lymph nodes. Impairment of meningeal lymphatic function slows the influx of CSF macromolecules and the efflux of ISF macromolecules, leading to cognitive impairment. Treatment with vascular endothelial growth factor C (VEGF-C) enhances meningeal lymphatic drainage, improving brain perfusion and cognitive performance in aged mice. In AD transgenic mouse models, disruption of meningeal lymphatic vessels promotes amyloid deposition in the meninges and exacerbates parenchymal amyloid accumulation. These findings suggest that meningeal lymphatic dysfunction may contribute to age-associated cognitive decline and AD pathology, highlighting potential therapeutic targets for preventing or delaying neurological diseases.