Stem Cells May Help Reverse Paralysis
Tests Succeed in Paralyzed Rats; Method May Help People, Scientists Say
June 21, 2006 -- With some chemical help, embryonic stem cells may help
reverse paralysis, tests done on paralyzed rats show.
The technique, described in the July issue of the Annals of
Neurology, hasn't been tested on people yet.
But, based on the results seen in adult rats, the method may be a
"potential therapeutic intervention for humans with paralysis," write
the researchers. They include Deepa Deshpande, MS, MBIOT, and Douglas Kerr, MD,
PhD, both of Johns Hopkins University in Baltimore, Md.
This isn't the first time scientists have tested stem cells in paralyzed
animals. But the new study's method differs from that in past experiments.
Stem cells can develop into different types of cells, although embryonic
stem cells may have a wider range of possibilities than adult stem cells.
Stem Cell Test
In this experiment, the scientists first did some lab work on embryonic mice
stem cells. They used chemicals to tell the cells to become motor neurons,
which are nerve cells that control muscles.
The mouse stem cells spent 3.5 days growing into motor neurons in the
Then, researchers transplanted them into the spinal cords of 120 paralyzed
As part of the experiment, the scientists created a key test group of 15
paralyzed rats. Those rats got a deluxe stem cell package souped up with three
- Chemical pretreatment of the stem cells to help new motor neurons
- Chemicals to help the rats' bodies accept the stem cells
- Chemicals that told the stem cells where to park to help one of the rats'
For comparison, the other rats got few or none of these additives with their
Partial Reversal of Paralysis
Six months later, 11 of the 15 rats in the key test group could put weight
on the paralyzed hind paw their stem cells had been instructed to target. Those
rats could also step off from that paw.
None of the other rats in the study were able to do that.
But even in the key test group, paralysis recovery was only partial; the
rats couldn't move the hind paw that hadn't been targeted by the stem
Rats in the key test group made 125 new nerve connections to muscle, 50 of
which reached and worked in the targeted hind paw.
The other rats had similar numbers of surviving, transplant-derived motor
neurons. But without the full package of chemical perks, those motor neurons
didn't bring paralysis recovery, the study showed.
In short, embryonic stem cells show promise against paralysis in rats, but
it may take extra chemical help to get the biggest benefits.