The human brain is a complex structure made up of different types of cells. You have probably heard scientists talk about nerve cells or brain cells. These are the cells that are lost in Alzheimer’s disease. However, there are a similar number of other cell types within the brain, called glial cells. Glial, comes for the Greek word for glue; as these cells were originally believed to hold the nerve cells together. It is now clear that these cells are highly specialised and vital for brain function. There are 3 main cell types that fall within the glia family:
1. Astrocytes: so-called star shaped cells, they are responsible for maintaining the environment that the nerve cells exist in;
2. Microglia: the brain’s resident immune cells, they are effectively the brain’s police force protecting against injury and infection; and
3. Oligodendrocytes: these cells insulate the wiring of the brain, acting as the brain’s resident ‘Bob the Builder.’
Dementia researchers, like myself, are keen to investigate what happens to all 3 types of glial cells in Alzheimer’s disease. My interest lies in understanding the role astrocytes play in brain diseases.
What do we know already?
Astrocytes are one specific type of glia that are being widely studied, in the hope that they provide novel avenues for developing medicines to treat Alzheimer’s disease. We know that unlike nerve cells, astrocytes are not lost in Alzheimer’s disease. While the number of astrocytes remains the same, their activity changes dramatically as the disease progresses. We are now starting to understand these changes and the impact they have on brain health.
Astrocyte in green (as featured in Biochemical Journal)
For example, astrocytes act as biological hoovers to remove chemical messengers in the brain. In Alzheimer’s, this function is compromised which leads to a build-up of these toxic chemicals leading to the death of the nerve cells. What we are keen to know is if this is a consequence of the disease or an early indication that the brain is changing because of the Alzheimer’s disease. If it is an early indication, then we could exploit it to target Alzheimer’s disease before symptoms appear. This could radically change the way we view Alzheimer’s disease.
While current Alzheimer’s disease drugs target nerve cells to manage symptoms (e.g. donepezil), we need new medicines. Our hope is that by understanding astrocytes we can begin the journey to a new medicine that could better manage Alzheimer’s disease. There is also the possibility that because these cells are changed early in the disease process they could prove cellular markers for Alzheimer’s disease. Our hope as dementia scientists is that these cells could unlock a new avenue of treatments that alters the course of Alzheimer’s disease for future generations.
Your donations are helping support Dr Dallas’ research, which he’s recently been asked to summarise in a review of progress for the research community. You can read the full review here.