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DISCOVERIES

Research offers insights into how ALS wreaks its havoc

STEM CELLS
A pair of studies has elucidated the mechanisms underlying some forms of amyotrophic lateral sclerosis, or ALS, and has shown the usefulness of stem cells in modeling the disease and pointing out new possibilities for treatment. Serge Przedborski and his colleagues at Columbia University and Kevin Eggan and his colleagues at Harvard University generated motor neurons from animal-derived embryonic stem cells and then cultured some of the neurons with astrocytes, star-shaped cells found in the brain and spinal cord. Both teams found that motor neurons were killed by astrocytes carrying a genetic mutation linked to ALS, showing that one type of brain cell was destroying the neurons controlling movement and likely leading to the degenerative paralysis of the disease. The finding addresses a longstanding question within ALS research: whether motor neurons die due to an intrinsic problem or to some external factor. It also highlights an important role of embryonic stem cells, said Eggan, a stem cell scientist. "Most people think of embryonic stem cells as useful for replacing cells that have been damaged by disease, but it might also be really useful to turn into the types of cells that a disease affects and then observe what happens."

BOTTOM LINE: Some cases of ALS appear to be caused by diseased astrocytes acting on motor neurons. This finding, based on animal-derived embryonic stem cells, has helped scientists shed light on a long-running debate within ALS research.

CAUTIONS: The mechanism observed applies to a small percentage of ALS cases. Also, research using human cells might yield different results than research based on animal cells.

WHAT'S NEXT: Eggan hopes the finding will help pave the way for the development of ALS drugs. He also sees the current research as validation for the usefulness of human embryonic stem cells.

WHERE TO FIND IT: Nature Neuroscience, April 15

AMI ALBERNAZ

GERIATRICS

Practicing Tai Chi boosts immunity to the shingles virus

Shingles is caused by the same virus that causes chickenpox -- the virus remains latent throughout life, acting up in older adults whose immunity is declining. Shingles affects one in five people who have had chickenpox, but there are no treatments, and the available vaccine is effective in only half the people who take it. In a recent study led by Dr. Michael Irwin of the University of California at Los Angeles, researchers looked at the effectiveness of Tai Chi, known to improve immunity, in boosting resistance to shingles virus. Researchers measured shingles virus-immunity in 112 adults over a 25-week period. Fifty-nine were doing Tai Chi and the rest were going through a health education program that included sleep and stress management and exercise for immunity improvement. The participants, between 59 and 86, had all had chickenpox earlier in life. At the end of 16 weeks, participants were given the shingles vaccine and their immunity was measured again nine weeks later, at the end of the study period. Researchers found that prior to the vaccine only the Tai Chi group showed an increased shingles immunity. After the vaccine, both groups showed a boost in immunity levels but the Tai Chi group's increase was almost double that of the control group -- in fact, the Tai Chi group's shingles immunity was as good as those of adults 30 years younger.

BOTTOM LINE: Practicing Tai Chi appears to boost the effectiveness of the shingles vaccine and improve disease immunity.

WHAT'S NEXT: "We want to see how Tai Chi boosts the effect of the shingles vaccine and if it has a similar effect on influenza and pneumonia vaccines," said Irwin, the study's lead author.

CAUTIONS: This is the first study of its kind and involved a small number of participants. More and larger studies are required to confirm these findings.

WHERE TO FIND IT: Journal of American Geriatrics Society, April.

SENA DESAI GOPAL

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