The reason your three-pound brain doesn’t feel heavy is that it floats in a reservoir of cerebrospinal fluid (CSF), which flows in and around your brain and spinal cord.
This liquid barrier between your brain and skull protects it from a hit to your head and bathes your brain in nutrients.
But the CSF has another critical, if less known, function: it also provides immune protection to the brain.
In a study from Northwestern Medicine, scientists found its role in cognitive impairment, such as Alzheimer’s disease. This discovery provides a new clue to the process of neurodegeneration.
The researchers found that, as people age, their CSF immune system becomes dysregulated.
In people with cognitive impairment, such as those with Alzheimer’s disease, the CSF immune system is drastically different from healthy individuals.
To analyze the CSF, the team used a sophisticated technique called single-cell RNA sequencing.
They profiled 59 CSF immune systems from a spectrum of ages by taking CSF from participants’ spines and isolating their immune cells.
The first part of the study looked at CSF in 45 healthy individuals aged 54 to 83 years.
The second part of the study compared those findings in the healthy group to CSF in 14 adults with cognitive impairment, as determined by their poor scores on memory tests.
The team found genetic changes in the CSF immune cells in older healthy individuals that made the cells appear more activated and inflamed with advanced age.
In the cognitively impaired group, inflamed T-cells cloned themselves and flowed into the CSF and brain. Scientists found the cells had an overabundance of a cell receptor—CXCR6—that acts as an antenna.
This receptor receives a signal—CXCL16—from the degenerating brain’s microglia cells to enter the brain.
The team says the future goal is to block that radio signal or inhibit the antenna from receiving that signal from the brain.
They want to know what happens when these immune cells are blocked from entering brains with neurodegeneration.
If you care about Alzheimer’s disease, please read studies about how the Mediterranean diet could protect your brain health, and a healthy lifestyle can help people live longer with no Alzheimer’s.
For more information about brain health, please see recent studies about antioxidants that could help reduce dementia risk, and Coconut oil could help improve cognitive function in Alzheimer’s.
The study was conducted by David Gate et al and published in Cell.
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