After a stroke event, the damaged area of the brain becomes inflamed. While this was once believed to be a harmful process, it may actually play an essential role in healing
Inflammation is generally considered a bad thing, and indeed if left to continue unchecked in most cases it is. However, it also plays a crucial role in healing and defence when appropriately controlled. Many stroke patients recover gradually over time, regaining lost abilities. Exactly how they do this isn’t known, but researchers now think the immune system plays a key role in repairing affected areas of the brain.
Inflammation can be beneficial
A stroke event causes widespread cell death in a section of the brain, and immune cells are immediately drawn to the site – causing inflammation. Among these cells are monocytes, a particular type of immune cell, and some of these cells in turn become macrophages as the reach the damage zone. New research has indicated that these cells, far from causing more damage, actually clear the area of dead tissue and release encouraging growth factors.
“This is in total contrast to our previous beliefs”
In the new study, a research team deliberately lowered levels of these monocytes in the blood of animals exhibiting a model of stroke. Curiously, those animals with depleted immune cells showed poorer, delayed recovery in comparison to the other group. Following this discovery, they analysed the brain further and confirmed that stem cells were becoming new nerve cells, and that inflammatory activity was actually aiding this recovery process.
The current treatment for stroke is primarily focused on dissolving the culprit blood clot, but this research suggests other later treatments could involve stimulating this natural recovery process. The team plans to test next whether stimulating increased monocyte production following a stroke actually quickens healing even more.
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