In biology, we learn that the brain is surrounded by three layers: the dura, arachnoid and pia mater. Well, that was true until recently. Researchers from the University of Copenhagen and University of Rochester have now identified a previously undistinguished layer of tissue they say helps protect our gray and white matter.
Molecular biologist Kjeld Møllgård and his team call the new layer, which is only a few cells thick, the Subarachnoid LYmphatic-like Membrane (SLYM). The researchers found SLYM between two other membranes that protect the brain. The new membrane, Science Alert reported, “appears to act as a barrier for molecules in our brain fluid that are larger than around 3 kilodaltons; comparable to an extremely small protein.
“The discovery of a new anatomic structure that segregates and helps control the flow of cerebrospinal fluid in and around the brain now provides us much greater appreciation of the sophisticated role that CSF plays not only in transporting and removing waste from the brain, but also in supporting its immune defenses,” University of Rochester neuroscientist Maiken Nedergaard said in a press release.
The SLYM is a kind of membrane called mesothelium. Mesothelium — which also line our lungs, heart and other organs, and contain immune cells — protect organs. According to the research, it appears to separate “clean” and “dirty” CSF.
Credit: University of Copenhagen
Credit: University of Copenhagen
So abnormalities in SLYM function might worsen multiple sclerosis, Alzheimer’s and other diseases, the teams suggested. Although the majority of the team’s research was done on mice, the researchers said they found the membrane in an adult human brain, too.
The study was published Thursday in the journal Science.
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