New research out of Germany successfully proved the concept of neuron transplant in mice, according to an article in the Huffington Post. A neuron transplant in humans could help repair the damage caused by traumatic brain injury or stroke. Scientists are hard at work trying to find a way to replace the brain cells that would otherwise be permanently lost after brain injury.
In the study, the embryonic neurons transplanted in the mice model formed proper connections with neighbors and restored function. This needs to happen for the neuron transplant to be a success. Scientists just can’t transplant new neurons into mature brain cells and expect them to grow as they should, because neurons form connections and are guided by physiological signs early in development.
“Transplantation aims to replace lost neurons, but the extent to which new neurons can integrate into existing circuits is unknown,” the study says. The transplantation of embryonic neurons in mice in their experiment was successful. After four weeks, the transplanted cells became the kinds of cells normally seen there in that area of the brain. After weeks, they became “indistinguishable from those of host neurons,” according to the study.
However, there are some challenges to still consider. The transplanted cells might do more harm than good if the cells become cancerous. The risks of brain surgery might in some cases outweigh the benefits the transplanted neurons would bring. Also, brain injuries can be complicated and not clear cut. A lot more work like this needs to be done still to ensure the safety of patients undergoing this procedure.
Glial cells also need to be taken into account. They form scars when the brain is damaged. The research team is looking into turning glial cells into new neurons that would replace the lost ones.
In fact, some kinds of neuron transplants have been done before. In patients with Parkinson’s disease, dopamine- producing cells deep in the brain are lost. There have been transplants of neurons that secrete dopamine, but these cells don’t need to be integrated into the current circuitry. They also don’t need to be human cells either. The first transplant of this type was done with pig cells.
Some researchers are looking into the use of pluripotent stem cells, which are adult cells that can be taken from the skin, for example. These kinds of cells can be programmed to behave like an embryonic stem cell. Researchers now need to show that these pluripotent cells can be integrated into the brain’s wiring.
Scientists seem optimistic about the current research in mice. “I’m excited about this study,” Sunil Gandhi from the University of California, Irvine, who was not involved with the study, told the Huffington Post. “This is evidence that the brain can accept the addition of new neurons, which normally doesn’t happen. That’s very exciting for its potential for cell-based repair for brain.”
One of the researchers, Magdalena Götz, was from Ludwig-Maximilians University and the Institute of Stem Cell Research at the Helmholtz Center in Munich, Germany. “What we did there is proof of concept,” she told the Huffington Post. “We took the best type of neurons, chosen at a specific time, and then we put them in the lesioned brain. That was to find out how well can it work.”
The study was published in the journal Nature last Wednesday.