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
powerful.

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.

Source:

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

Researchers Transplant Genetically Modified Heart Cells from Mice into Pigs

Even when someone survives a heart
attack, significant amounts of muscle tissue die, damaging the heart. The
Associated Press recently reported on a technology which someday may allow
such tissue to be regrown.

The March 17 story described experiments
conducted at the Louisiana State University Medical Center by Dr. William
C. Claycomb. Claycomb sucessfully transferred genetically modified heart
cells from mice into the damaged heart of a pig, where the cells survived
and acted like normal heart muscle, although it is unclear if the mouse
cells actually assisted in the working of the pig heart.

Although any use in humans for
this sort of technology is years, if not decades away, the importance of
this experiment is demonstrating that it is at least possible.

“It is a very important advance,”
said Dr. Kenneth R. Chien, a professor of medicine at the University of
California, San Diego. “The work challenges the dogma that it is
not possible to create a cell line that displays the unique features of
an intact heart.”