Inflammation kills new brain cells

A research team at Lund University in Sweden attracted international attention a year ago by showing that new nerve cells can be generated in the brain after a stroke. However, most of these new nerve cells die rather soon. The same research team has now been able to show that an inflammation can lie behind the death of these new nerve cells, which instills hope for improved treatments for various brain disorders.

The new growth of nerve cells following epilepsy or stroke has been shown in animal studies to take place in two parts of the brain: the striatum and the hippocampus (a part that is of special importance for the memory, learning, and moods). These same areas are involved in the new formation of nerve cells in the human brain as well.

But many of the newly generated nerve cells perish rather quickly. The Lund research team, including Professor Olle Lindvall, Associate Professor Zaal Kokaia, and Doctor of Medicine Christine Ekdahl Clementson, have now been able to explain in an article in Proceedings of the National Academy of Sciences in the US that this is largely caused by an inflammatory process. They have demonstrated this in two ways: both by inducing an inflammation, which led to the death of nerve cells, and in reverse experiments by administering anti-inflammatory medicine, which reduced the number of nerve cells that died.

Inflammation of the brain occurs not only in connection with epilepsy and stroke but also in Alzheimer’s and other forms of dementia. In the future the new discoveries might lead to improved treatment of these diseases. But a great deal of research remains to be done.

“First we need to find out what function the newly formed nerve cells have. We know that the cells are of the same sort as those that are lost in a stroke, for example, but we don’t know whether the cells become fully functional to the point where they could help repair damage,” says Associate Professor Zaal Kokaia.

“We also want to learn more about the inflammatory process, which is extremely complicated. It triggers a number of different substances, and we would like to know which of them are causing cell death.”

The Lund scientists are going to pursue both of these leads in their further research.

This also has bearing on research into stem cells, which the Lund team is also working with, since transplanted cells probably also risk dying from inflammations that arise in the brain.