Swedish scientists have succeeded in restoring mobility and sensation of touch in stroke-afflicted rats by reprogramming human skin cells to become nerve cells.
The nerve cells were then transplanted into the part of the rat’s brain most often damaged by the stroke.
Professor Zaal Kokaia of Lund University says: “Six months after the transplantation, we could see how the new cells had repaired the damage that a stroke had caused in the rats’ brains.”
Several previous studies from the Lund team and others have shown that it is possible to transplant nerve cells derived from human stem cells or from reprogrammed cells into brains of rats afflicted by stroke.
However, it was not known whether the transplanted cells can form connections correctly in the rat brain in a way that restores normal movement and feeling.
Kokaia adds: “We have used tracking techniques, electron microscopy and other methods, such as light to switch off activity in the transplanted cells, as a way to show that they really have connected correctly in the damaged nerve circuits.
“We have been able to see that the fibres from the transplanted cells have grown to the other side of the brain, the side where we did not transplant any cells, and created connections. No previous study has shown this.
Fellow researcher Olle Lindvall explains: “It is remarkable to find that it is actually possible to repair a stroke-damaged brain and recreate nerve connections that have been lost.
“The study kindles hope that in the future it could be possible to replace dead nerve cells with new healthy nerve cells also in stroke patients, even though there is a long way to go before achieving that.”
The researchers now aim to undertake further studies in this area.
Kokaia says: “We want to know more about how the transplanted cells affect the opposite hemisphere of the brain. We also want to take a closer look at how a transplant affects intellectual functions such as memory.
“In addition, we will study possible side effects. Safety is, of course, extremely important for cell transplantation if it is going to be used clinically in the future.”
The study was published in the research journal PNAS.
