Immune cells mediate the repair of blood vessels following traumatic brain injury

2017

Challenge

Mild traumatic brain injuries (mTBI), such as concussions, induce significant damage to blood vessels in the lining of the brain. Little is known about whether these damaged blood vessels are repaired following mild traumatic brain injury (mTBI) or to what degree secondary injuries influence the recovery process. 

Advance

IRP researchers led by Dorian McGavern, Ph.D., demonstrated that approximately 83 percent of mTBI patients repair their damaged blood vessels, whereas 17 percent fail to recover over a three-month period. By studying an animal model of mTBI, the investigators further showed that different subsets of blood-derived immune cells called monocytes are required for cleanup of dead cells and to promote the regrowth of injured blood vessels. Importantly, a secondary injury encountered within 24 hours of the initial mTBI completely aborted this repair process.

Impact

The team’s findings demonstrate that the peripheral immune system plays an essential role in repairing damage within the brain lining following mTBI and that secondary injuries encountered too soon after the primary injury can adversely affect the regenerative program. This study has implications for policies governing when patients should be allowed to resume their normal physical activities, such as participation in contact sports.

Publications

Russo MV, Latour LL, McGavern DB. (2018). Distinct myeloid cell subsets promote meningeal vascular remodeling and repair following mild traumatic brain injury. Nat Immunol. May;19(5):442-452.