The brain is the most important organ of the body, but it is still not fully understood. In addition to neurons that share information, the brain contains other cells that help to maintain the brain. Researchers from the University of Stanford have started to take a look at how these non-neuronal cells affect brain health. It turns out at a type of cell called astrocytes normally nourishes neurons, but they can become toxic in certain conditions.
Helpful Astrocytes May Turn Harmful After Illness or Injury
Astrocytes are one of the most abundant types of cells in the brain. Scientists have found that they help to support and nourish neurons. Though astrocytes are not actually nerve cells, they can even create neurotransmitters to help regulate brain activity. If a patient gets nerve damage, helpful astrocytes work to regenerate and reconnect the cut fibers.
These astrocytes might seem beneficial, but a new study by Stanford neuroscientist Shane Liddelow shows that they can also be malignant. In the study that was just published in Nature Journal, Liddelow explains that the researchers examined astrocyte effects in mice. When brains are exposed to inflammation due to either disease or injury, astrocytes convert into A1 cells that primarily create immune system proteins. These A1 cells do not contain the building functions of normal astrocytes.
Instead, they try to remove damaged neurons so that new, healthy cells can grow. Unfortunately, this process can get a little out of balance if something goes wrong. The end result can be excessive amounts of A1 astrocytes that remove partially functioning neurons without replacing them with fully functional neurons. The researchers corroborated these finds by doing autopsies on patients who passed away from neurodegenerative conditions. There were very high levels of A1 astrocytes present.
Astrocytes are normally regarded as the good guys, but here we have convincing evidence of a well-defined mechanism for how they contribute to different types of pathologies.
Study Could Be Used to Treat Neurodegenerative Diseases
Any research that provides more information about the underlying mechanisms behind neurodegeneration can be extremely helpful. One in nine people over the age of 65 has Alzheimer’s disease, a condition that makes it hard for them to remember anything or think logically. Neurodegeneration does not just occur among seniors either, so people as young as 20 can get multiple sclerosis which causes the protective coating on nerves to degrade.
These types of illnesses have been extremely hard to treat because doctors did not understand why nerve cells were suddenly degenerating until they no longer functioned. Liddelow is particularly excited about the impact of his study because it may “provide a wealth of information about why neurons die in neurodegenerative diseases such as Alzheimer’s, and why there is demyelination of axons in diseases such as multiple sclerosis.”
Now that this mechanism is better understood, doctors can began theorizing and experimenting with ways to remove harmful A1 astrocytes before they damage the brain. It may take years of research before any definitive treatment is produced, but Liddelow’s study is an important stepping stone on the way to getting a cure.
The Next Research Steps
Neuroscientists will now need to confirm Liddelow’s findings and take a deeper look at how astrocytes may be contributing to certain brain disorders. They can then work to find a method for inhibiting A1 astrocyte expression in at risk patients. The main difficulty in creating some sort of medicine will be targeting the right cells. Researchers will need to find a way to remove harmful A1 astrocytes without harming the beneficial types of astrocytes.
Photo by Donald Ogg, available under a Creative Commons Attribution-NonCommercial-NoDerivs 2.0 Generic license.