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Immune cells in the brain and cerebrospinal fluid become dysregulated as we age, getting a little ‘angry’.
The reason the brain is weightless is because it is encased in a reservoir of cerebrospinal fluid (CSF), which flows in and around the spinal cord and brain, protecting them from potential blows. At the same time, it provides the brain with the Necessary nutrients and immune protectionnoticed the Sci Tech Daily.
A Northwestern Medicine study of the CSF, recently published in Cell, discovered its role in cognitive impairments, such as Alzheimer’s disease. This analysis provides a new clue to the process of neurodegeneration, said David Gate, lead author of the study.
During the investigation, the team discovered that, as people age, their CSF-associated immune system becomes deregulated. In people with cognitive impairment, such as Alzheimer’s, the immune system at the CSF level is drastically different from those found in healthy individuals.
“We now have a glimpse of the brain’s immune system with healthy aging and neurodegeneration,” said Gate, professor in the Ken & Ruth Davee Department of Neurology at Northwestern University Feinberg School of Medicine.
“This immune reservoir could be used to treat brain inflammation or be diagnostic to determine the level of brain inflammation in individuals with dementia,” he continued.
To analyze the CSF, the team used the single-cell RNA sequencing technique. They profiled 59 immune systems across a spectrum of ages by taking CSF from the participants’ spines and isolating immune cells.
In a first phase, they analyzed the CSF of 45 healthy individuals, aged between 54 and 83 years. In the second phase, they compared the results with those obtained in 14 adults with cognitive impairment, a state determined by poor scores on memory tests.
The team observed genetic alterations in the CSF immune cells of healthy elderly individuals, which made them more active and inflamed.
“Immune cells seem to be a little irritated in older individuals. we think that this anger can make cells less functionalresulting in the deregulation of the brain’s immune system”, indicated the researcher.
In the cognitively impaired group, “the inflamed T cells cloned and flowed through the CSF and into the brain as if they were following a radio signal,” explained Gate.
The researchers also found that the cells had an overabundance of a cell receptor – CXCR6 – which acts as an antenna. This receptor receives a signal – CXCL16 – from degenerative cells to enter the brain.
“It could be the degenerated brain activating these cells and to make them clone themselves and circulate in the brain”, indicated Gate. “They don’t belong there and we’re trying to figure out if they contribute to brain damage,” he said.
The team’s future goal is to “block that radio signal, or inhibit the antenna from receiving that signal from the brain”.
“We want to know what happens when these immune cells are blocked and blocked from entering brains with neurodegeneration,” he continued.
ZAP // 
