Stem cells continue to show promise in treating certain neurological conditions such as strokes, but it appears it isn’t because the stem cells are replacing the damaged cells, as predicted. In NewScientist (21 January 2017, paywall) Jack Price has a report:
Source: How Stuff Works
Rats injected with stem cells following a stroke recovered sensation and movement to a degree rarely seen before. On closer inspection, though, there was a surprise. The reason it worked wasn’t because dead and dying cells had been replaced with shiny new ones, although this did happen to some extent. Even when stem cells remained in their immature state and didn’t differentiate at all, they still contributed to recovery. In many cases, the implanted cells didn’t even survive for more than a few weeks, but still the animals showed significant recovery.
What seems to be happening is that stem cells release growth factors and other chemicals that stimulate the brain to heal itself, potentially giving compromised circuits the ability to regroup and reorganise. Some of these chemicals may also boost the immune system, reducing inflammation and helping to stimulate blood vessel growth – all crucial if a newly mended bit of brain is going to thrive. In fact it could even be that this plays a more important part in brain fixing than cell replacement.
Can the growth factors be produced without the stem cells? Is it possible to apply them to spinal cord injuries and other nerve damage? It’s rather like reprogramming the cells to return to an earlier phase of life. If it is, then it may be a very productive avenue for healing catastrophic injuries.
