Immune Cells Repair Damage to Blood-Brain Barrier in Mice

TUESDAY, Jan. 12, 2016 (HealthDay News) — Researchers report in a mouse study that they have found that central nervous system immune cells play a key role in repairing the blood-brain barrier.

The blood-brain barrier prevents harmful substances in the blood from getting into the brain. If that barrier is breached, the brain becomes vulnerable to infection and injury, the researchers explained.

In experiments with mice, scientists found that immune cells in the brain called microglia are crucial in repairing damage to the blood-brain barrier.

The researchers made small holes in the brain-blood barrier of mice and found that nearby microglia immediately started to repair the damage. In most cases, the brain-blood barrier was restored within 10 to 30 minutes, the researchers noted.

However, it’s important to keep in mind that animal research doesn’t always turn out the same way in humans.

“This study shows that the resident immune cells of the central nervous system play a critical and previously unappreciated role in maintaining the integrity of the blood-brain barrier,” lead author Dr. Maiken Nedergaard, co-director, Center for Translational Neuromedicine, University of Rochester Medical Center in New York, said in a center news release.

The study was published Jan. 11 in the journal Proceedings of the National Academy of Sciences.

The researchers saw that a particular receptor activated the microglia and directed them to the blood-brain barrier breach. The same receptor is also present on platelets and is one of the targets of blood-thinning drugs such as Plavix, the researchers noted.

These drugs are given to at-risk patients to prevent platelets from clumping and forming blood clots that can cause a stroke, the researchers explained. However, these findings suggest that these drugs may impair the repair of the blood-brain barrier after a stroke, and the researchers are currently investigating this possibility.

“When this barrier is breached it must be rapidly repaired in order to maintain the health of the brain and aid in recovery after an injury — a process that could be impaired by drugs that are intended to prevent this damage in the first place,” Nedergaard explained.

“Our concern is that while certain types of blood-thinning drugs may do a great job preventing strokes, they could have the unintended consequence of making them worse or hindering recovery once they occur,” she said.

More information

Neuroscience for Kids has more about the blood-brain barrier.