Researchers are developing a new treatment which they believe could reverse the devastating disabilities caused by stroke. Trials involving rats have shown that cognitive skills and movement could be returned and the first human trials are planned for late next year.
Dr John Sinden, chief scientific officer of a private company, ReNeuron Ltd, described efforts to use cloned human neural cells as a way to repair the brain damage caused in stroke patients. The technique uses neural stem cells, a form of progenitor cell that once inside the brain can specialise into the various forms of nervous tissues. "Stem cells exist in all body parts, even in the brain," Dr Sinden told a session of the festival. The company had already used rat stem cells "as a way to elicit repair in animals", he said. "We have shown the animals are capable of showing signs of recovery." The stem cells were cultured and between five and 10 million cells - a tiny volume given these cells' size - were injected into the injured rats' brains.
These migrated to the sites of damage and differentiated into the appropriate cell type, returning some function within several weeks. The company was now working on a human equivalent, based on a neural stem cell line cultured from cells provided with parental permission from dead foetuses. These were engineered to make the cell line "immortal" and capable of long-term division. The cell line was also altered to include a mutant gene taken from a monkey virus, which is used as a "switch" that will turn off cell division once the cells are injected into the brain. This gene allows the cells to divide and multiply when cultured at 33 degrees. When the cells warm up to normal body temperature, 38 degrees, the gene switch is triggered and cell division stops, Dr Sinden explained.
"The ultimate goal is to reverse the effects of chronic disability caused by stroke," he stated.