The lymphatic system plays a crucial role in maintaining homeostasis within the body, with an emerging body of research underscoring its role in supporting the central nervous system (CNS). The glymphatic system has further been recognized as being pivotal to these functions, as demonstrated by a 2024 study published in Communications Biology.
Composed of lymphatic vessels, nodes, and specialized lymphoid organs, this expansive network is essential for governing fluid balance, immune surveillance, inflammation, and the clearance of cellular debris and foreign agents by removing excess fluid, metabolic waste, and pathogens from tissues and filtering these cleansed substances back into the bloodstream.
This vast system extends through the spleen, thymus, liver, and gut, facilitating the transport of lymphatic fluid, or lymph, through lymphatic channels and filtering it via lymph nodes, prior to returning it to the bloodstream for elimination. Notably, the liver and intestines contribute to 80% of the body’s lymph production.
In addition to transporting interstitial fluid, the lymphatic system also distributes glucose, lipids, cholesterol, amino acids, immune cells, and neurotransmitters, having implications for both immune and neuronal health. This process is closely linked with the glymphatic system, a specialized waste-clearance pathway in the brain that functions most actively during sleep.
While the body’s lymphatic network is widespread, the CNS was once thought to lack traditional lymphatic vessels, raising questions regarding how the brain clears waste. Somewhat recent findings, however, have uncovered the presence of lymphatic-like structures in the brain’s meninges, particularly in the basal and dorsal regions. These structures suggest that the brain has its own lymphatic system, with meningeal lymphatics playing a role in governing immune and inflammatory processes within the CNS.
Lymphatic vessels in the dura and meninges help transport cerebrospinal fluid (CSF), surrounding the brain and spinal cord, flushing out cerebral waste such as amyloid-beta—associated with neurodegenerative conditions, such as Alzheimer’s disease.
Research suggests that CSF is modulated through these channels that are remarkably active during sleep, underscoring the significance of sleep for promoting brain health and detoxification. Through the glymphatic system, CSF moves out of the brain and spinal cord, while also draining out of the CNS to the lymphatic system in the body, further underscoring their pivotal connections.
Disruptions in lymphatic and glymphatic flow, such as prolonged disrupted sleep, therefore may contribute to compromised central nervous system function, in light of these findings, highlighting their role in governing neuroimmunity.
The glymphatic system and meningeal lymphatics work in conjunction to efficiently remove harmful substances from the brain that may otherwise impede neurological health. These processes rely on perivascular channels formed by astroglial, a type of glial cell that helps regulate the blood-brain barrier and supports waste clearance.
A growing body of research underscores the relationship between glymphatic dysfunction and mental health conditions. A scoping 2024 review published in Current Neuropharmacology demonstrates a link between glymphatic dysfunction and psychiatric conditions, including sleep disorders, depression, anxiety, schizophrenia, autism spectrum, trauma-related, cocaine and alcohol use disorders. This system’s role in cerebral waste clearance underscores its significance in maintaining neurological health.
System dysfunction is suggested to be associated with disruptions in circadian rhythm, neuroinflammation, poor sleep, and impeded astrocyte function—all of which contribute to the accumulation of waste products in the brain.
Sleep, therefore, is crucial for optimizing the function of both the glymphatic and lymphatic systems. Disrupted sleep impedes the functioning of these vital systems, which can result in the accumulation of harmful proteins and metabolites in the brain. A 2021 review published in Sleep Medicine Reviews found that after just one night of sleep deprivation, amyloid-beta levels increased, suggesting that poor sleep may contribute to neurodegenerative conditions. Furthermore, sleep disturbances are associated with increased oxidative stress and inflammation in the brain, which can exacerbate the risk of neurological disorders.
Crosstalk between the glymphatic system, GI, cardiovascular system and lymphatic system has also been demonstrated. A growing body of research shows that the signals for this central nervous system and systemic crosstalk, utilizes glymphatic and lymphatic pathways, with important implications for neurological and immune health.
As emphasized, a large portion of the lymphatic system is also present in the gut, influencing both immune function and waste elimination. This is noteworthy as the brain-gut-microbiota axis has been largely identified as influencing CNS function. Disruptions in gut microbiota can trigger systemic inflammation, imbalances in neurotransmitter release, and impede the blood-brain barrier—all of which affect neurological health.
The lymphatic system plays a critical role in immune and neurological function, systemically as well as via the glymphatic system. Impairment of these systems are associated with increased risk of neurodegenerative conditions where the breakdown of the blood-brain barrier and the infiltration of immune cells into the glymphatic system contribute to neuroinflammation and dysfunction. By clearing excess fluid and waste products from the body and brain, these pivotal systems support CNS function and prevent harmful substance buildup.
Lifestyle practices including sleep position, sufficient omega-3 fatty acid consumption, diaphragmatic breathing and yoga have been implicated to support lymphatic flow, enhancing the glymphatic system’s ability to clear waste. Optimizing sleep quality, massage, mitigating stress and promoting states of relaxation in the body, are further ways to stimulate these systems, supporting overall CNS health.
The lymphatic and glymphatic systems are integral to the functioning of the central nervous system by promoting detoxification of systemic and neurotoxic waste, while governing neuroimmune surveillance. Adequate sleep is necessary for optimizing these systems, while disruptions in sleep can compromise their functions, increasing susceptibility to impeded neurological and immune health. Understanding the connections between these systems is significant for maintaining homeostasis in the body and mind.