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Activity may stave off Huntington’s

By Malcolm Ritter - AP Science Writer

A study in mice suggests that people who carry the defective gene that causes Huntington’s disease might be able to delay the onset of symptoms by keeping busy in a stimulating environment.

Mice took longer to show symptoms if they lived in cages with plenty of objects to play with and explore. Scientists were cautious about applying that result to people but said it is worth studying. For one thing, nobody knows what part of the mouse experience made the difference - overall physical activity, mental stimulation or something else.

Huntington’s is a degenerative brain disorder that slowly diminishes a person’s ability to walk, talk and think. No cure or effective treatment is known. Symptoms generally begin between ages 30 and 45, though people who have inherited the defective gene can be identified much earlier through a blood test.

The study of 16 mice was reported in Thursday’s issue of the journal Nature by Dr. Anton van Dellen and Anthony J. Hannan of Oxford University, with colleagues.

Half of the mice lived in a standard cage, with all the food and water they could drink and a soft material for bedding. The other half lived in an ‘enriched’ environment that also included tunnels, boxes, tubes and other objects of cardboard, paper and plastic. New objects were switched for old ones every couple of days. The mice explored them, crawled under and over them and tore off pieces of cardboard and paper. Researchers tested the animals for movement abnormalities that appear in the rodent version of Huntington’s. One abnormality - difficulty in turning around on a narrow rod - appeared in only one of seven mice from the enriched cage but in all nine from the standard cage by the time testing concluded at 22 weeks of age. Another abnormality, clasping of hind paws when held aloft by the tail, appeared in half of the ‘enriched’ animals by that time, vs. all of the other mice.

The results suggest that mental or physical activity might help stave off Huntington’s in people, but more research is needed, Hannan said. Dr. Christopher Ross, a professor of psychiatry and neuroscience at Johns Hopkins University, said it would be premature to change behaviour substantially because of a single mouse study. The idea would be worth testing in people if further animal study bears it out, he said.

Any effect on the appearance of symptoms would probably be modest, but even that would be helpful because nothing is known to affect the progression of the disease, he said.