Scientists at Lund University in Sweden showed long ago they could reprogram human cells into nerve cells and implant them into the brains of rats after a stroke. But would the cells form the vital connections needed to restore mobility and sensations like touch?
Now, they have early evidence that the answer to that question is yes. The Lund team turned skin cells into nerve cells, transplanted them into the brains of the rodent stroke models and observed them for six months. The new cells repaired the damage caused by strokes in the animals, the researchers reported in the journal PNAS.
The Lund University team transplanted the reprogrammed skin cells into the rats’ cerebral cortices, the region of the brain that’s most commonly damaged by stroke. Then they used electron microscopy and other technologies to track the cells. That allowed them to see that the cells were making the connections needed to repair damaged nerve circuits.
“We have been able to see that the fibers 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,” said co-author Zaal Kokaia, professor of neurology at Lund, in a statement.
Cell therapy has been proposed for treating stroke damage in the past, but efforts to make it a reality have hit some roadblocks. A stem cell therapy being developed by British biotech ReNeuron failed to hit its primary trial endpoint of improving arm and leg movements. ReNeuron has since turned in better results from a trial of its cell therapy for improving vision in patients with retinitis pigmentosa.
Meanwhile, academic researchers are testing a variety of other therapies aimed at repairing stroke damage. Last year, for example, Stanford researchers showed that blocking a particular microRNA prompted star-shaped brain cells called astrocytes to become neurons, which helped restore memory in rats.
The Lund team is now planning additional animal trials to study how their transplanted cells affect memory and other intellectual functions, they said. They will also watch the rats closely to make sure they aren’t experiencing side effects, and they’ll study the impact of the transplants on regions of the brain.