Neuro-lymphatics 2/3 - when waste isn’t cleared
What the glymphatic system does
In the last post, I talked about how waste gets cleared from the brain via the glymphatic system and meningeal lymphatics. The spaces around the blood vessels get used to transport excess fluid and waste from the interstitial fluid of the brain, move it to the lymphatic vessels of the face and neck, and from there the lymphatic system clears it out into the bloodstream to be filtered by the liver and kidneys.
The glymphatic system is critical for the health of our brains. As a transportation system, the glymphatic system clears out metabolic waste, especially the proteins that act as toxins to the brain. It helps distribute nutrients. It helps with moving signals between brain cells. It maintains homeostasis and immune function in the brain.
When the glymphatic system doesn’t work
Degenerative brain diseases are often characterized by the accumulation of protein molecules - those same protein molecules that the glymphatic system is supposed to clear. Scientists are actively studying which conditions are linked with problems with glymphatic function, and new articles come out all the time.
Neurodegenerative conditions linked with the glymphatic system include:
Alzheimers
Parkinson’s
ALS (amyotrophic lateral sclerosis)
MS (multiple sclerosis)
Cerebral small vessel disease
Many other conditions are linked to glymphatic dysfunction. In some cases, the impaired glymphatic clearance makes it harder to heal, such as:
Stroke
Concussion
Brain injury
Chemo brain
In other conditions, it’s hard to tell whether they cause glymphatic problems or are the result of them.
Long COVID
Diabetes
Depression
Migraines
Sleep apnea
Epilepsy
Encephalitis
Schizophrenia
Insomnia
Age-related cognitive changes
Cognitive changes are particularly linked with glymphatic changes. In a number of studies studying many of the above conditions, worse cognitive function is correlated with worse glymphatic function.
To translate that to English instead of Medical: the more toxins build up in the brain, the more brain fog someone is likely to have.
How does this work?
New research is coming out all the time, but I can give you a simplified version of my understanding of (at least part of) the process as of February 2025. When waste isn’t cleared properly from the brain, protein molecules start accumulating in the fluids in and around the brain. As those protein molecules and waste accumulate, inflammation starts to happen in the brain. Inflammation leads to degeneration - brain cells get damaged and even destroyed, resulting in various neurological diseases. Inflammation leads to brain fog, and problems with thinking and memory. Inflammation also aggravates the problems with the glymphatic system, leading to waste being cleared even less effectively - which, of course, leads to more inflammation again.
How do we break this cycle? That’s the next article.
Want to read my sources?
Here's some of the research I used to write this article.
