UC Irvine research that used mice who had brain injuries showed that after they received stem cell treatments, their memory was restored to the same level as mice who did not have any injuries. It took about three months for the stem cells to bring about these results.
They believe that this occurs because the stem cells secrete a group of proteins known as neurotrophins that have the ability to protect the damaged cells from dying off and also restored their memory.
The hope is that these results will lead to the production of a drug that will have the capacity to boost the level of the proteins and help patients regain their memory.
The mice that were used in the research are genetically engineered to develop brain lesions in any part of the brain that the researcher wants them too. In this study, the researchers destroyed the cells located in the region of the brain called the hippocampus, which is one region of the brain that is responsible for forming the person’s memory. It is also a region where neurons are known to die off.
In order to test the memory in two groups of mice, one that had healthy mice and one that had the brain injuries. Both sets of mice were given place and object recognition tests.
Each one of these functions is controlled by a different region of the brain. Remembering a place is controlled by the hippocampus, the region that was damaged, and the ability to remember objects is controlled by the cortex.
When they did the test to remember a place, the healthy mice were able to remember their surroundings 70% of the time.
With the brain damages mice, it was 40%. When it came to remembering an object, the healthy mice accomplished it close to 80% of the time and the brain damaged one, 65% of the time.
The next part of the research was to find out if neural stem cells taken from a mouse would have the ability to improve the memory in the brain damaged mice. For this test they gave each of the mice an injection that contained about 200,000 neural stem cells. These cells were made to look green when they were put under ultraviolet light. This makes them easy to keep track of as they settle inside the brain.
At the three month mark in the research, the mice were once again tested on place recognition. The brain damaged mice who also received the stem cells remembered their location 70% of the time, as did the healthy ones. The brain damaged mice who did not get the injection of stem cells still showed the same level of memory impairment.
Step number three was to take a look at how the stem cells were acting. One thing they found was that just about 4% of the stem cells had actually become neurons. This means that they were not improving the level of memory just by replacing the dead brain cells alone. In the healthy group, the stem cells simply traveled throughout all the regions of the brain. In the brain damaged mice, the cells grouped together in the hippocampus. What they found to be most interesting was the fact that at the four month level the brain injured mice who had the treatments, actually had more neurons that the healthy ones.
The lead researchers on the project are Frank LaFerla, who is a professor of neurobiology and behavior at UCI, Matthew Blurton-Jones and Tritia Yamasaki. The rest of the team is
UCI scientists Debbi Morrissette, Masashi Kitazawa and Salvatore Oddo also worked on this study, which was funded by the National Institute on Aging, the National Institutes of Health, and a California Institute for Regenerative Medicine postdoctoral scholar award.
Source: UC Irvine http://today.uci.edu