Astrocytes have long been considered
primarily support cells for neurons, the cells that make up the nervous system.
While many functions of astrocytes do provide support for neurons, including structural
and metabolic maintenance, recent studies have suggested much larger
implications for this type of glia cell.
Alzheimer’s Disease is a common neurodegenerative
disorder that affects more people than any other disorder of this category. The
disease’s characteristic markings are amyloid plaques and neurofibrillary
tangles that can be seen upon brain tissue examination after death. These
plaques play a large role in the dementia aspect of Alzheimer’s, disrupting
connectivity and inducing neuron death, among other destructive functions.
There is new evidence to suggest that there
may be a complex relationship between astrocytes and amyloid plaques present in
Alzheimer’s Disease. To aid in the survival of neurons, astrocytes will
surround areas of brain tissue that are damaged by plaques and consume the
harmful proteins. This is all done with the good intention of helping neurons
survive, however there is a harmful byproduct that results from this phagocytosis
process. The byproduct coming from this process includes hydrogen peroxide, which
is neurotoxic and causes immediate neuronal cell death. It has been debated whether
this phagocytosis then is actually worse for neurons than the plaques
themselves. There is plenty more research to be done on this topic.
These results were phenomenally exciting
when they were released and started an extremely important shift in the conversation
about glia cells that may lead to curative measures for a multitude of
disorders of the nervous system. The next step in developing a cure for Alzheimer’s
may be to find a way to degrade these harmful byproducts before they can kill neurons.
This could potentially allow astrocytes to continue cleaning up plaques from
healthy tissue without the devastating side effects.
https://www.ncbi.nlm.nih.gov/pubmed/?term=Astrocyte%E2%80%93neuron+metabolic+relationships%3A+for+better+and+for+worse
Alzheimer's is an extremely relevant and devastating disease in our world today so if we could find a potential cure for Alzheimer's that would be a major breakthrough. It sounds like your research shows that doctors have been developing some potential cures which could potentially cause side effects which would end the patient's life anyway. Like you said, if we could find a way to stop those harmful byproducts before they kill the patients neurons this could be a huge breakthrough! You said in your post that doctors are able to see the destroyed brain tissue postmortem, so when would patients start to undergo this neural therapy if doctors can not see the potential harm created until after the patients death? Would they start their procedure as soon as patients show symptoms? This is an amazing study which could save many lives.
ReplyDeleteI certainly agree with Morgan that this study could change the almost certain death diagnosis that many families receive when a loved is diagnosed with this horrible disease. With the phagocytosis process, could there be a way to possibly delete the hydrogen peroxide as a byproduct? Another thought to add to this discussion is could there be a way to artificially mimic what the astrocytes do to the plaques in the form of a pill that patients take that could breakdown the plaques and not have the extremely harmful byproduct of hydrogen peroxide? This study sounds like a really big breakthrough for scientists and could lead to a lot of amazing things!
ReplyDeleteHydrogen peroxide (H2O2) is neurotoxic, meaning that it is extremely harmful to neurons and will cause neuronal death upon contact. In the human body, catalase and peroxidase are two enzymes which break down hydrogen peroxide into molecules that are not toxic to our bodies, such as H2O and O2. If scientists are able to get these enzymes to the astrocyte locations before the hydrogen peroxide harms neurons, could we get one step closer to finding a cure for Alzheimer’s Disease? Rather than focusing on eliminating astrocyte’s production of the byproduct which is neurotoxic, maybe we should shift focus to cleaning up this neurotoxin before it can elicit its effects. I found an article, linked below, which describes the mechanisms by which catalase as well as peroxidase work to catalyze H2O2.
ReplyDeleteThanks for this post, it was a very interesting read!
https://chem.libretexts.org/Textbook_Maps/Inorganic_Chemistry_Textbook_Maps/Map%3A_Bioinorganic_Chemistry_(Bertini_et_al.)/5%3A_Dioxygen_Reactions/Catalase_and_Peroxidase