Mice Research Offers Possible Approach to Stopping Huntington's Disease

Researchers at the University of Iowa in Iowa City this month made public the results of their research into stopping dominant progressives brain disorders in mice.

A dominant progressive brain disorder is a disease caused when an infant inherits one copy of a mutant gene which results in the production of mutant proteins that cause loss of cognitive abilities. The most widely occurring form of this sort of disease in the United States is Huntington’s disease, with as many as 250,000 sufferers in this country alone. Huntington’s disease usually manifests itself in a victim’s mid-to-late 30s and sufferers typically live only 15-20 years after diagnosis while suffering progressively worsening brain degeneration.

The University of Iowa researchers used gene therapy to treat mice afflicted spioncerebellar ataxia type 1. The disease produces a mutated protein in the brain that eventually leads the mice to have difficulty in walking. Like Huntington’s it is not a result of a missing gene — which gene therapy has traditionally been used to treat in animal models and in a small number of humans — but rather a mutant gene inherited from a parent.

Nonetheless, researchers used a virus to carry modified genetic material to the mice. The genetic material was designed to bind with and block the expression the defective gene. After the mice were injected with the virus, the production of the proteins causing the disease stopped and the mice appeared to improve their ability to walk.

The researchers then took the process one step further and used the same method to see if genetic material could be effective when added in vitro to human Huntington’s cell cultures. After exposing the cell cultures to a different virus containing the genetic materials, the cells stopped producing the proteins that cause Huntington’s disease.

Lead researcher Beverley Davidson said the she hopes this discovery moves quickly into clinical trials to see if it can be effective in treating Huntington’s in human beings,

The data are very promising; we hope we will be able to use RNA interference as a therapy for dominant neurodegenerative diseases.


Cure hoped for Huntington’s sufferers. Erika Chek, Nature, June 9, 2004.

Mouse Research Yields Gene Therapy Hope for Huntington's

The BBC recently reported on a successful effort in mice to treat Huntington’s with gene therapy. Huntington’s is a genetic disease that is incurable and results in the degeneration of the brain and eventual death among sufferers.

Researchers at the University of Iowa used gene therapy to shut off the affected gene entirely in mice. Shutting off the gene entirely in human beings is not an option, but there is another possibility. Human beings have two copies of this gene, and in most Huntington’s sufferers only one of the genes is defective. If researchers could turn off the defective gene, they could at least slow the progress of the disease.

So far, though, such gene therapy has shown limited success in slowing a similar disease human cells in laboratory conditions, but is still a long way from testing a gene therapy cure in human beings.


Gene therapy hope for Huntington’s. The BBC, March 13, 2003.

Future promises more genetically engineered animals

As animal rights activists point
out ad nauseum, animal models are not completely analogous to human beings.
Substances which cause cancer in rats sometime fail to cause cancer in
human beings and vice versa. But what if researchers genetically engineered mice and rats to suffer from the same illnesses human beings suffer from?
Well now they can, which is creating an enormous debate about the ethics
of such animal research.

Until recently, scientists relied on
finding mutant strains of mice which suffered from diseases or symptoms
similar to those experienced by human beings. Mice commonly used to test
cancer treatments, for example, are specially bred to be highly prone
to developing cancer.

Advances in biotechnology take
that one step further and allow scientists to alter the genes in mice
embryos so they are born with specific defects such as cystic fibrosis
or arthritis. As National Institutes of Health immunologist Ronald Schwartz
recently told the Washington Post, such animal models should be incredibly

John Sharp, superintendent of induced
mutant resource at the Jackson Laboratory, put it bluntly. “More and
more research is moving toward the use of these mice. It’s where
the future of research is headed.”

And it is not just mice. Researchers
at laboratories around the world are genetically altering pigs, goats
and sheep to do everything from produce more easily transplantable organs
to providing delivery mechanisms for medicine in their milk.

As genetic engineering of animals
spreads, so does the opposition movements aimed at limiting or banning it. Those
opposed to such genetic engineering complain it is wrong to design animals
to suffer.

“There really is something
primordially horrible about replicating animals that will suffer endlessly,”
|Bernard Rollin|, a Colorado State University physiologist, told the Washington Post. Other attack genetic engineering as challenging our notions of life
as inherently sacred.

The biggest opposition in recent
years came in Switzerland, where 112,000 Swiss citizens signed a petition
to put a ban on research on genetically altered animals on the ballot.

Failing to use these genetically
engineered animals, however, will mean ignoring an excellent source of
medical information. Genetically engineered mice have already yielded
important information about deadly human illnesses such as |Huntington’s| disease. When scientists removed a gene in mice which corresponds to the
defective human gene that causes Huntington’s, researchers noticed
small protein deposits in the brains of the mice; something that had not
been observed in Huntington’s patients. Upon reexamining the brains
of Huntington’s victims, however, researchers indeed found the protein
deposits, which are now suspected as one of the primary causes of the
diseases’ symptoms.


Rick Weiss, “Creation of flawed animals raises new ethics issues,”
Washington Post, June 7, 1998.