A recent study at Northwestern University, USA, has uncovered CSF’s function in cognitive impairment, such as Alzheimer’s disease. The study revealed that the CSF immune system gets dysregulated with age. On comparing the CSF immune systems of people with cognitive disorders like Alzheimer’s disease with healthy individuals, a drastic difference was observed.
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It is because of the cerebrospinal fluid (CSF) that circulates inside of and around your brain and spinal cord, due to which the brain and skull are shielded from head trauma and saturated with nutrition. This CSF also has a critical yet less explored property, which is providing immunity to the brain.
How is CSF in cognitively impaired brains different from CSF in healthy brains?
This research was conducted by analysing CSF obtained from 59 individuals belonging to different age groups, using a special technique called single-cell RNA sequencing. This technique measures gene expression by RNA molecules in each cell of the given sample enabling the discovery of cellular differences.
The immune cells were isolated from the CSF acquired from the participants’ spines. Firstly, the CSF in 45 healthy participants aged between 54-83 years was examined and then compared with the CSF in 14 adults who were classified as cognitively impaired based on their poor performance in the memory test. This data analysis of the CSF of both groups has been shared on the internet.
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The CSF immune cells in older healthy participants showed genetic changes due to which cells appeared to be highly activated and inflamed with evolving age. The study suggested that this over-activation of cells makes them less functional, dysregulating the brain’s immune system.
On the other hand, in the cognitively impaired group, it was observed that inflammatory T-cells (immune cells) replicated and moved into the CSF and brain as though they were following a radio signal. The cells were revealed to have an excess of CXCR6, a cell receptor that serves as an antenna. The microglia cells in the degenerating brain provide a signal CXCL16 to this receptor, allowing it to enter the brain.
The Conclusion of this Study
The research was published in the journal Cell.