It's been not long ago that people believed that the lymphatic vessels in the brain do not penetrate until it was disproved after the experiment with mice and now also with humans.
Vessels of the lymphatic system supplement the blood vessels. They branch around the body, transferring immune cells, vesicles with lipids and other molecules, removing the products of their vital activity from the organs and tissues. Only the brain was considered an organ where lymphatic vessels did not penetrate, which led to the question of how it gets rid of a serious amount of "waste"? It was only a few years ago after the experiments on laboratory mice it became possible to detect lymphatic vessels in the upper dura mater.
What they have found shocked specialists who were accustomed to classical views taken from textbooksñ many of them started to explore the lymphatic system of the brain. Daniel Reich and his colleagues from the American National Institute of Neurological Disorders and Stroke (NINDS) used a highly sensitive tomography for this. The results of their work are presented in an article published by the eLife journal.
Scientists conducted scanning of the cerebral vessels on five healthy volunteers. At the same time, the contrast medium gadobutrol was used, the molecules of which are small enough to pass through the walls of blood vessels and enter the external cerebral membrane, but are too large to overcome the blood-brain barrier and to be found in the internal parts of the brain itself.
Such observations showed the presence in the outer shells of the brain of a branched network of the finest lymphatic vessels, almost as thick as the blood vessel. The experiment was repeated with two volunteers who also received a second contrast, with larger molecules that are unable to leave the blood capillaries to further confirm these results. So the specialists managed to identify the vessels of the circulatory and lymphatic systems in the hard shell of the brain, resulting that there are both of them in there.