Stem cells take first step
fwiw...
theaustralian.news.com.au
Best of Luck,
SS
>>>>
Stem cells take first step
June 22, 2006
WASHINGTON: Scientists have used stem cells and a soup of nerve-friendly chemicals to bridge a damaged spinal cord and regrow the circuitry needed to move a muscle, helping partially paralysed rats walk again.
Years of additional research is needed before such an experiment could be attempted in people. But the work marks a tantalising step in stem cell research that promises one day to help repair damage from spinal cord injuries.
"This is an important first step, but it really is a first step, a proof of principle that ... you can rewire part of the nervous system," said Douglas Kerr, a neurologist at Johns Hopkins University in Maryland, who led the research team.
Perhaps most importantly, the US experiment illustrates that even if stem cells do live up to their promise, treatment will not be simple.
The research details a complex recipe of growth factors and other chemicals that entice the cells to form correctly and make the right connections.
Miss a single ingredient and the cells wander aimlessly, unable to reach the muscle and make it move.
The study may bring "the appropriate tempering of expectations of stem cells", Dr Kerr said. "Some of my patients say, 'Oh, I'm going to pull into the stem-cell station and get my infusion of stem cells', and it's never going to be that."
Stem cells are building blocks that turn into different types of tissue. Embryonic stem cells, in particular, have made headlines as scientists attempt to harness them to regenerate damaged organs or other body parts.
They are essentially a blank slate, able to turn into any tissue given the right biochemical instructions. But human embryonic stem cell research is controversial, because culling the cells destroys embryos.
The Hopkins experiment is not the first to use stem cells to help paralysed rodents move. However, previous work bridged damage inside the spinal cord that prevented nerve cells delivering their "move" messages tomuscles.
The new work essentially installs new wiring, replacing motor neurons - specialised nerve cells for movement - that have died, to make a new circuit that grows neuronal connections out of the spinal cord and down to a leg muscle.
First, Dr Kerr mixed embryonic stem cells from mice with chemicals that caused them to turn into motor neurons.
Then he transplanted them into the spinal cords of partially paralysed rats.
Some rats received neurons treated with substances to boost their survival chances.
Some received injections of chemicals to neutralise substances that inhibit the growth of motor neurons.
Others were injected with a growth factor near the leg muscle, as a signpost to direct the new neurons to form connections there.
Only the group of rats that got every extra ingredient improved, Dr Kerr found.
Six months after treatment, 11 of the 15 rats could take steps. |
