Brain conjugation system provides new insights into aging and immunity

Brain conjugation system provides new insights into aging and immunity

summary: A new study has revealed a direct connection between the brain and its dura mater, challenging previous beliefs about the brain’s isolation. This connection facilitates the exit of waste fluids and the interaction of the immune system, highlighting the importance of arachnoid exit points (ACEs) in brain health and disease management.

The findings, supported by advanced magnetic resonance imaging and microscopic imaging, suggest that ACE points play a critical role in diseases such as Alzheimer’s by influencing waste removal and immune system reactions. In addition, the study found that aging may increase the leakage of these points, which may be associated with an increased risk of neurodegenerative diseases.

Key facts:

  1. The study discovered a direct pathway for fluid waste and immune cells between the brain and the dura mater, challenging the idea of ​​complete isolation of the brain.
  2. Arachnoid cuff exit points (ACEs) have been identified as critical areas where the brain’s waste removal system interacts with the immune system, which may influence the development of neurological disorders.
  3. The research found an association between aging and increased leakage of ACE points, suggesting a possible link to a higher risk of neurodegenerative diseases.

source: National Institutes of Health

In a recent study of the brain’s waste disposal system, researchers from Washington University in St. Louis, in collaboration with researchers at the National Institute of Neurological Disorders and Stroke (NINDS), part of the National Institutes of Health (NIH), discovered a direct connection between the brain and its tough protective covering. , dura mater.

These connections may allow waste fluid to leave the brain while also exposing the brain to immune cells and other signals coming from the dura. This challenges conventional wisdom that suggests that the brain is isolated from its surroundings by a series of protective barriers, keeping it safe from dangerous chemicals and toxins lurking in the environment.

This indicates the brain.
One implication of ACE points is that they are areas where the immune system can be exposed to and react to changes occurring in the brain. Credit: Neuroscience News

Daniel S. said: “Waste fluids move from the brain into the body just as sewage leaves our homes,” says Reich, MD, of NINDS. “In this study, we asked the question of what happens when ‘drain pipes’ leave the ‘home’ – in this case, the brain – and connect to the city sewer system inside the body.” Reich’s group worked jointly with the laboratory of Jonathan Kipnis, Ph.D., a professor at Washington University in St. Louis.

Reich’s lab has used high-resolution magnetic resonance imaging (MRI) to observe the relationship between the brain and the body’s lymphatic system in humans. At the same time, Kipnis’ group was independently using live-cell microscopy and other brain imaging techniques to study these systems in mice.

Using MRI, the researchers scanned the brains of a group of healthy volunteers who had received injections of gadobutrol, a magnetic dye used to visualize disturbances in the blood-brain barrier or other types of blood vessel damage.

Large veins are known to pass through the arachnoid barrier that carries blood away from the brain, and this has been clearly observed in MRI scans.

As the scan progressed, a ring of dye appeared around those large veins that slowly spread over time, indicating that fluid could be making its way through the space surrounding those large veins as it passed through the arachnoid barrier on its way to the dura.

Kipnis’ lab was making similar observations in mice. His group injected mice with light-emitting molecules. As with MRI experiments, the fluid containing these light-emitting molecules was seen sliding through the arachnoid barrier where blood vessels passed.

Together, the laboratories found a “collar” of cells that surround blood vessels as they pass through the arachnoid space. These areas, which they called arachnoid cuff exit (ACE) points, appear to function as areas where fluids, molecules and even some cells can pass from the brain to the dura and vice versa, without allowing the two fluids to fully mix.

In some disorders such as Alzheimer’s disease, poor waste removal can lead to the buildup of disease-causing proteins. Continuing the sewer analogy, Kipnis explained the possible connection to ACE scores:

“If your sink is clogged, you can remove the water from the sink or fix the faucet, but ultimately you need to fix the drain,” he said. “In the brain, blockages at ACE points may prevent waste from getting out. If we can find a way to clear these blockages, we may be able to protect the brain.

One implication of ACE points is that they are areas where the immune system can be exposed to and react to changes occurring in the brain. When mice in Dr. Kipnis’ lab were induced to develop a disorder in which the immune system attacks myelin in the brain and spinal cord, immune cells could be seen around ACE dots and even between the blood vessel wall and cuff cells; This over time led to the collapse of the ACE point itself.

When the ability of immune cells to interact directly with ACEs was blocked, the severity of infection decreased.

“The immune system uses molecules to deliver that transit from the brain to the dura mater,” Kipnis said. “This transit needs to be strictly regulated, otherwise harmful effects on brain function can occur.”

Reich and his team also observed an interesting relationship between participants’ age and ACE score leakage. In older participants, more dye leaked into the surrounding fluid and perivascular space.

“This may indicate a slow breakdown in ACEs over the course of aging, and this may have an effect where the brain and immune system can now react in ways they’re not supposed to,” Reich said.

The association with aging and disruption of the barrier between the brain and the immune system fits with what has been observed in aging mice and in autoimmune disorders such as multiple sclerosis.

This newly discovered connection between the brain and immune system could also help explain why our risk of developing neurodegenerative diseases increases as we age, but more research is needed to confirm this link.

Financing: This study was supported by the NINDS Intramural Research Program, the National Institute on Aging (AG034113, AG057496, AG078106), and the BEE Consortium for the Treatment of Alzheimer’s Fund.

About this neuroscience research news

author: Carl Wonders
source: National Institutes of Health
communication: Carl Wonders – National Institutes of Health
picture: Image credited to Neuroscience News

Original search: The results will appear in nature

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