Scientists from the University of Queensland (UQ) in Australia have found a new type of cell that clears waste away from the brain. They suggest that their findings will increase our understanding of the brain’s biology and of diseases such as dementia and stroke.The researchers report the discovery of the new type of lymphatic cell in the journal Nature Neuroscience.
They found the cell in freshwater zebrafish, which provide a useful model for studying human biology because many of their cells and organs are similar to ours. Another advantage of using zebrafish is that they are transparent; the scientists were able to use advanced light microscopes to see what was happening in their brains.
The lymphatic system has three main functions:
- It is part of the immune system;
- It returns fluid from tissues to the blood;
- and it absorbs fat-soluble nutrients and fats from the digestive tract and carries them to the bloodstream.
The lymphatic system
The lymphatic system comprises: a fluid called lymph that is similar to blood plasma, vessels that carry lymph, and organs – such as the lymph nodes, tonsils, thymus, and spleen. It is similar to the cardiovascular system in that it carries fluid through a network of vessels that permeates nearly every type of tissue in the body. However, whereas the cardiovascular system has a pump – that is, the heart – to move blood through the vessels, the lymphatic system relies on contraction of smooth muscle in its vessel walls, together with movement of skeletal muscle and breathing to push the lymph along.
Facts about the lymphatic system
- Unlike blood vessels, lymphatic vessels only carry fluid away from tissues.
- The lymphatic system produces white blood cells in response to infection.
- It helps to keep blood volume and blood pressure normal and prevents edema.
Isolated lymphatic cells in the brain
For a long time, it was thought that the brain did not have any lymphatic vessels, but a recent landmark discovery showed that it does and that the reason it took so long to find them is because they are ‘very well hidden.’
Now, in the new study, the UQ researchers make another surprising discovery in finding that the brain may also contain isolated lymphatic cells that help to clean up waste that leaks from the bloodstream.
Prof. Ben Hogan, an associate professor in the Institute for Molecular Bioscience at UQ, says: “The cells appear to be [the] zebrafish version of cells described in humans called ‘mato’ or lipid-laden cells.” He adds that in humans, mato cells “clear fats and lipids from the system but were not known to be lymphatic in nature.”
Hogan: “Our focus now is to investigate how these cells function in humans and see if we can control them with existing drugs to promote brain health, and improve our understanding of neurological diseases such as stroke and dementia.”
Source: Medical News Today | May 2nd, 2017