Swamping bad cells with good slows spinal cord diseaseOctober 20th, 2008 - 12:00 pm ICT by IANS
Washington, Oct 20 (IANS) Transplanting a new line of stem cells into rat models of Lou Gehrig’s disease, that ends in fatality, slows down neuron loss and extends life, a new study has found.Also known as amyotrophic lateral sclerosis or ALS, Lou Gehrig’s disease afflicts nerve cells in the brain and spinal cord.
The new work supports the hypothesis that swamping unhealthy cells with healthy ones in targeted parts of the spinal cord preserves limb strength and breathing and can increase survival.
Two parts of the study hold special interest: One is that the target area for the added cells - parts of the cervical spinal cord that control the diaphragm muscles largely responsible for breathing - reap the most benefit.
Forty-seven percent more motor neurons survived there than in untreated model animals. Respiratory failure from diaphragm weakness is the usual cause of death in ALS, also called Lou Gehrig’s disease.
“While the added cells, in the long run, didn’t save all of the nerves to the diaphragm, they did maintain its nerve’s ability to function and stave off death significantly longer,” said neuroscientist Nicholas Maragakis, associate professor of neurology at Johns Hopkins, who led the research team.
“We intentionally targeted the motor neurons in this region,” he said, “since we knew that, as in ALS, their death results in respiratory decline.”
Also significant is that the transplanted cells, called glial restricted precursors (GRPs), address a well-known flaw in people with ALS and in its animal models, according to an ALS Association release. The work was published online in Nature Neuroscience.
Both humans and models are stunted in their ability to clear away the neurotransmitter glutamate. And excess glutamate - common in ALS - overstimulates the motor neurons that spark muscle movement, causing death. The event, called excitotoxicity, also occurs in other neurological diseases.
In their research, the team transplanted some 900,000 glial restricted precursors overall to specific sites in the cervical spinal cord of each model rat in early stages of disease.
The GRPs the scientists used began life as what’s called astrocyte progenitor cells from healthy rat spinal cord tissue. Following transplant, they transformed into mature, healthy astrocytes, found living alongside sick motor neurons.