Neuron transplantation

Traumatic brain injuries occur annually in two million Americans, accompanied by cell death and brain inflammation. Patients after traumatic brain injury often suffer from memory impairment, and are also at risk of developing epilepsy.

Researchers from the University of California, Irvine transplanted embryonic progenitor cells capable of generating inhibitory insertion neurons - a special type of nerve cells that control the activity of brain circuits – into the brains of mice after traumatic brain injury. They had to function in the hippocampus, the area of the brain responsible for learning and memory.

The researchers found that the transplanted neurons migrated to the area of traumatic injury and formed new connections with brain cells, functioning for a long time. After a month, the mice showed signs of improved memory, such as the ability to distinguish the box in which they experienced unpleasant sensations from the one in which there were no unpleasant sensations. These mice coped with memory tests in the same way as mice who had never had a traumatic brain injury. Cell transplants also prevented the development of epilepsy in animals, which affected more than half of untreated mice.

Inhibitory neurons are critically important in the brain's memory function, and they are extremely vulnerable after a traumatic brain injury. It is impossible to stop the death of neurons, but now it is possible to replace them and restore the connections between them.

This is not the first time Robert Hunt and his group have used insertion neuron transplantation to restore memory in mice. In 2018, they used a similar approach to treat newborn mice with genetic memory impairment. The idea of growing neurons instead of those who died after a traumatic brain injury is not new, neuroscientists have been trying to do this for a long time. But transplanted cells often do not survive, cannot migrate, or do not develop into functioning neurons.

To test their observations once again, Hunt and his group injected mice with a drug that turned off the transplanted neurons, and their memory problems resumed. This showed that the transplanted neurons were indeed the cause of memory improvement.

If the results in mice can be reproduced in humans, it may be very useful for patients who have suffered a traumatic brain injury. The next step of the group is to create insertion neurons from pluripotent human stem cells.

Article B.Zhu et al. Transplanted interneurons improve memory precision after traumatic brain injury is published in the journal Nature Communications.

Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on the materials of the UCI School of Medicine: Researchers develop cell therapy to improve memory and stop seizures in mice following traumatic brain injury.