The recent discovery by the University of Virginia claimed to have found the undiscovered connection between the brain and the immune system, which may lead to a change of biology textbooks. Until now, the medical world believed the brain and lymphatic system were not connected with each other.
The lymphatic system is vital for fighting infection in the body while draining excess fluid from the tissue. This study aimed to look at the circulation of lymph in the mouse brain, potentially creating a greater understanding of the workings of the brain and disease processes.
Published in Nature, scientists discovered previously unknown lymphatic vessels in the protective outer layers of the brain called the meninges. These vessels follow an important blood vessel down into the sinuses, an area that has been traditionally difficult to obtain images of appeared to link the brain and spinal cord with the rest of the body’s immune system. They seem to carry fluid and immune cells from the cerebrospinal fluid (the fluid surrounding the brain and spinal cord).
"Instead of asking, 'How do we study the immune response of the brain?', 'Why do multiple sclerosis patients have the immune attacks?', now we can approach this mechanistically," Prof. Jonathan Kipnis clarifies, "because the brain is like every other tissue connected to the peripheral immune system through meningeal lymphatic vessels."
The researchers also found that the vessels looked different with age, suggesting they may play a role in the aging process.
Further studies are needed to confirm these findings and to assess whether this knowledge is transferable to humans.
Louveau, A., Smirnov, I., Keyes, T. J., Eccles, J. D., Rouhani, S. J., Peske, J. D., ... & Kipnis, J. (2015). Structural and functional features of central nervous system lymphatic vessels. Nature.