In:
eLife, eLife Sciences Publications, Ltd, Vol. 6 ( 2017-10-03)
Abstract:
How does the brain rid itself of waste products? Other organs in the body achieve this via a system called the lymphatic system. A network of lymphatic vessels extends throughout the body in a pattern similar to that of blood vessels. Waste products from cells, plus bacteria, viruses and excess fluids drain out of the body’s tissues into lymphatic vessels, which transfer them to the bloodstream. Blood vessels then carry the waste products to the kidneys, which filter them out for excretion. Lymphatic vessels are also a highway for circulation of white blood cells, which fight infections, and are therefore an important part of the immune system. Unlike other organs, the brain does not contain lymphatic vessels. So how does it remove waste? Some of the brain’s waste products enter the fluid that bathes and protects the brain – the cerebrospinal fluid – before being disposed of via the bloodstream. However, recent studies in rodents have also shown the presence of lymphatic vessels inside the outer membrane surrounding the brain, the dura mater. Absinta, Ha et al. now show that the dura mater of people and marmoset monkeys contains lymphatic vessels too. Spotting lymphatic vessels is challenging because they resemble blood vessels, which are much more numerous. In addition, Absinta, Ha et al. found a way to visualize the lymphatic vessels in the dura mater using brain magnetic resonance imaging, and could confirm that lymphatic vessels are present in autopsy tissue using special staining methods. For magnetic resonance imaging, monkeys and human volunteers received an injection of a dye-like substance called gadolinium, which travels via the bloodstream to the brain. In the dura mater, gadolinium leaks out of blood vessels and collects inside lymphatic vessels, which show up as bright white areas on brain scans. To confirm that the white areas were lymphatic vessels, the experiment was repeated using a different dye that does not leak out of blood vessels. As expected, the signals observed in the previous brain scans did not appear. By visualizing the lymphatic system, this technique makes it possible to study how the brain removes waste products and circulates white blood cells, and to examine whether this process is impaired in aging or disease.
Type of Medium:
Online Resource
ISSN:
2050-084X
DOI:
10.7554/eLife.29738.001
DOI:
10.7554/eLife.29738.002
DOI:
10.7554/eLife.29738.003
DOI:
10.7554/eLife.29738.004
DOI:
10.7554/eLife.29738.005
DOI:
10.7554/eLife.29738.006
DOI:
10.7554/eLife.29738.007
DOI:
10.7554/eLife.29738.010
DOI:
10.7554/eLife.29738.008
DOI:
10.7554/eLife.29738.009
DOI:
10.7554/eLife.29738.011
DOI:
10.7554/eLife.29738.013
DOI:
10.7554/eLife.29738.012
DOI:
10.7554/eLife.29738.014
DOI:
10.7554/eLife.29738.015
DOI:
10.7554/eLife.29738.016
Language:
English
Publisher:
eLife Sciences Publications, Ltd
Publication Date:
2017
detail.hit.zdb_id:
2687154-3
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