Researchers at Massachusetts General Hospital and Harvard Medical School were imaging mice after stroke and meningitis when they noticed immune cells taking a shortcut from nearby skull marrow.
Herisson and Nahrendorf's team found microscopic channels through the inner layer of the skull bone, connecting skull marrow to the membrane covering the brain. In injured mice, neutrophils made by skull marrow reached the brain through these channels in greater numbers than identical cells from the shin bone, showing a more direct route.
The finding suggested the skull itself works as a local source of immune cells for the brain, not just a helmet protecting it, and it raised the question of whether drugs could be aimed at the skull marrow directly during stroke or brain inflammation. Similar channels appear in human skulls, but their role in people is unproven.
Read the original study
Herisson et al., Nature Neuroscience, 2018 · doi.org/10.1038/s41593-018-0213-2
The skull doubles as a pipeline.
Source
- Herisson, F., Frodermann, V., Courties, G., Rohde, D., Sun, Y., Vandoorne, K., Wojtkiewicz, G. R., Masson, G. S., Vinegoni, C., Kim, J., Kim, D.-E., Weissleder, R., Swirski, F. K., Moskowitz, M. A., & Nahrendorf, M. (2018). Direct vascular channels connect skull bone marrow and the brain surface enabling myeloid cell migration. Nature Neuroscience, 21(9), 1209–1217. https://doi.org/10.1038/s41593-018-0213-2