A study funded by the US National Institutes of Health discovered tiny tunnels that connect the skull’s bone marrow to the brain.
Published in the journal Natural Neuroscience, the study indicated the tunnels were used as a direct access point for immune cells from the bone marrow to enter the brain. These tiny tunnels were found connected from the brain’s lining to the skull, according to a statement.
The immune cells that enter the brain are in response to injuries caused by stroke and other brain disorders.
“We always thought that immune cells from our arms and legs traveled via blood to damaged brain tissue. These findings suggest that immune cells may instead be taking a shortcut to rapidly arrive at areas of inflammation,” said Dr. Francesca Bosetti, program director at the NIH’s National Institute of Neurological Disorders and Stroke.
The discovery may also open up more research opportunities for understanding brain diseases and finding cures for them.
The research team focused on monitoring the activity of neutrophils, immune cells that are first to arrive at injury sites, during the study. They tracked neutrophils in lab mice by treating the cells with a kind of dye. They would then induce a stroke and monitor which bone marrow in the body neutrophils would come from. They also found the same tunnels in human brains but five times larger.
Based on their observations, the body’s bone marrow did not uniformly release neutrophils to treat an injury. Rather, immune cell deployment may be localized wherever the injury is generally located. In this case, they saw the skull release more immune cells for the brain than, say, the farther tibia bone.
The next step for the study will seek to identify what other types of cells travel through the newly discovered tunnels and how the tunnels affect a person’s overall health or a brain disease. /ra
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