“This immune reservoir could potentially be used to treat inflammation of the brain or be used as a diagnostic to determine the level of brain inflammation in individuals with dementia.”
The cerebrospinal fluid (CSF) that circulates in and around your brain and spinal cord is the reason your three-pound brain doesn’t feel weighty. This layer of fluid between your brain and skull cushions it from blows to the head and provides essential nutrients.
But the CSF has another important but less well-known job: it keeps the brain’s immune system healthy. But little research has been done on this function.
A study done by Northwestern Medicine on CSF found that it plays a role in cognitive problems like Alzheimer’s. According to lead author David Gate, an associate professor of neurology at Northwestern University Feinberg School of Medicine, this finding offers a fresh insight into the process of neurodegeneration.
The work was published in Cell today.
According to the findings of the research, as individuals become older, the immune system in their CSF gets dysregulated. The research also found that the CSF immune system is significantly different in patients with cognitive impairment, such as those with Alzheimer’s disease.
“We now have a glimpse into the brain’s immune system with healthy aging and neurodegeneration,” says Gate.
“This immune reservoir,” according to Gate, “could potentially be used to treat inflammation of the brain or be used as a diagnostic to determine the level of brain inflammation in individuals with dementia.”
“We now have a glimpse into the brain’s immune system with healthy aging and neurodegeneration,” says Gate.
His team is making the data available to the public, and its findings are searchable online.
Gate’s team at Northwestern used a cutting-edge method called single-cell RNA sequencing to examine the CSF. They extracted CSF from participants’ spines, isolated the immune cells within it, and then analyzed 59 CSF immune systems across a range of ages.
In the first part of the study, 45 healthy people between 54 and 83 years old had their CSF tested. In the second part of the study, the researchers compared what they found in the healthy group to what they found in the CSF of 14 adults who had memory problems.
The team of scientists led by Dr. Gate identified genetic changes in the CSF immune cells of healthy elderly adults that caused the cells to seem more active and inflamed with advancing age.
“The immune cells appear to be a little angry in older individuals,” Gate adds. “We think this anger might make these cells less functional, resulting in dysregulation of the brain’s immune system.”
According to Gate, in the group with cognitive impairment, inflammatory T-cells cloned themselves and flowed into the cerebral spinal fluid and brain as if following a radio signal. Scientists found that the cells had too much of a cell receptor that acts as an antenna called CXCR6. This receptor enters the brain after receiving the CXCL16 signal from degenerating microglia cells.
“It could be the degenerating brain activates these cells and causes them to clone themselves and flow to the brain,” Gate adds. “They do not belong there, and we are trying to understand whether they contribute to damage in the brain.”
The team “future goal is to block that radio signal, or to inhibit the antenna from receiving that signal from the brain. We want to know what happens when these immune cells are blocked from entering brains with neurodegeneration.”
Gate’s lab will keep looking into what role these immune cells play in diseases of the brain like Alzheimer’s. They also want to include other illnesses, such amyotrophic lateral sclerosis (ALS).
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