A team from Stanford University, US, has shown that fetal stem cells can migrate to the site of stroke damage and restore lost cells, indicating their potential as a treatment. The research, published in Proceedings of the National Academy of Sciences, was carried out using human stem cells on rats, but the team hopes that it may be applicable in treating human stroke victims.
The brains of stroke victims, including rats, contain areas of damage which have fewer brain cells and a disrupted blood supply. This damage can impair abilities such as walking and speaking, depending on what part of the brain is damaged. The research team found that if they injected the fetal stem cell clusters, called neurospheres, directly into the area of damage, the cells survived in only one out of nine rats due to the limited blood supply. However, when the team injected the neurospheres up to 1.2 millimetres away, they migrated towards the area of damage and stayed alive for up to a month, producing neurones. It is thought these neurones may restore lost function, such as walking, but the team is yet to test this.
To test what caused the migration, the researchers injected neurospheres into normal rats. They found that the cells only moved around 0.2 millimetres, so it is likely that the damaged areas cause the neurospheres to migrate. Dr Gary Steinberg, who led the research team, said, 'We think and have some preliminary evidence that it [migration] is due to chemicals or chemokines being released in the stroke area'. Chemokines are a signalling chemicals that allow communication between cells.
The researchers compared fetal stem cells with adult stem cells, but found the adult stem cells did not survive as long or migrate as far. Embryonic stem (ES) cells were not used due to the federal funding restrictions imposed the US government, and because ES cells are not approved for use in humans. The researchers saw no point in experimenting with a procedure while regulation limits its application.
'We fully support any further developments in this specific field of stem cell research which may help stroke patients receive better treatment in future', said a spokesperson for the Stroke Association, careful not to condone ES cell research. Dr Michael Marks, from the Stanford Stroke Center, said, 'A therapy like this has tremendous potential'.