Doctors think they’ve worked out where ‘brain waste’ ends up in recent scientific research, believing it could be one of the potential causes for Alzheimer’s disease.
Scientists from Washington have uncovered how the brain gets waste out through the rigid protective barrier (known as dura mater), without using the body’s lymphatic system – a network that drains fluids throughout the body.
Where your ‘brain waste’ may end up
In February, scientists led by Dr Jonathan Kipnis, a neurologist at Washington University in St Louis, published an article titled ‘Identification of direct connections between the dura and the brain.’
Although the study was conducted in mice, researchers believe their findings match up with research on potential causes of Alzheimer’s disease and other health dementias.
This article discusses how the brain and the dura mater (a tough outer layer of tissue that covers and protects the brain) interact, answering the question of how the brain gets waste out through the rigid protective barrier without using the body’s lymphatic system – a network that drains fluids throughout the body.
The brain is not part of the lymphatic system, instead, its waste disposal pathway is known as the glymphatic system. It clears out waste generated by energy-consuming metabolic processes. Normally, a barrier called the arachnoid separates the brain and the dura mater, but communication between the two is essential for waste removal and immune responses.
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Researchers found specific structures, called arachnoid cuff exit (ACE) points, where veins cross the arachnoid barrier, allowing fluids and molecules to pass between the brain and the dura.
These ACE points help drain cerebrospinal fluid and allow some substances from the dura to enter the brain. In people with neuroinflammatory conditions, these points also let immune cells move directly from the dura to the brain.
This discovery highlights ACE points as crucial pathways for communication and waste clearance between the brain and dura in both mice and humans.
Research has the possibility to delay neurological diseases
Scientists uncovered exit points around the brain from which cerebrospinal fluid (which carries waste) flowed out to the thick membrane surrounding the brain and spinal cord and into the bloodstream, where the body’s lymphatic vessels took over to clear it out.
The research was then expanded further in an article, showing how that waste-laden liquid ends up at those exit points.
Findings showed signs that a slow wave of electricity, that pulses through the brain during sleep, pushes waste products from deep in the brain to its surface. The waste includes the protein closely associated with Alzheimer’s disease, indicating that there is the possibility of delaying or even preventing neurological diseases.
Scientists reported that as the brain sleeps, neurons fire in rhythmic waves that generate force, to flush cerebrospinal fluid through the brain and past the blood-brain barrier.
A researcher at Washington University and lead author of the second study, named Dr Li-Feng Jiang-Xie, stated: “If we can build on this process, there is the possibility of delaying or even preventing neurological diseases, including Alzheimer’s and Parkinson’s disease, in which excess waste – such as metabolic waste and junk proteins – accumulate in the brain and lead to neurodegeneration.”
