Download Cloning in Medicine

Cloning in Medicine
http://learn.genetics.utah.edu/content/cloning/whyclone/
Cloning for medical purposes has the potential to benefit large numbers of people. How might cloning be used in
medicine?
Cloning animal models of disease
Much of what researchers learn about human disease comes from studying animal models such as mice. Often, animal
models are genetically engineered to carry disease-causing mutations in their genes. Creating these transgenic animals
(one that carries a foreign gene that has been deliberately inserted into its genome) is a time-intensive process that
requires trial-and-error and several generations of breeding. Cloning could help reduce the time needed to make a
transgenic animal model, and the result would be a population of genetically identical animals for study.
Cloning to make stem cells
Stem cells build, maintain, and repair the body throughout our lives. Because these are processes that stem cells do
naturally, they can be manipulated to repair damaged or diseased organs and tissues. But stem cells transferred from
one person to another (such as in a bone marrow transplant) are seen as foreign, and they usually trigger an immune
response.
Some researchers are looking at cloning as a way to create stem cells that are genetically identical to an individual.
These cells could then be used for medical purposes, possibly even for growing whole organs. And stem cells cloned
from someone with a disease could be grown in culture and studied to help researchers understand the disease and
develop treatments.
In 2013, scientists at Oregon Health and Science University were the first to use cloning techniques to successfully create
human embryonic stem cells. The donor DNA came from an 8-month-old with a rare genetic disease.
Drug production
http://learn.genetics.utah.edu/content/cloning/whyclone/
Farm animals such as cows, sheep, and goats are being genetically engineered to produce drugs or proteins that are
useful in medicine. As an example, scientists could take cells from a cow that produces large amounts of milk and grow
them in culture. Then they could insert a gene into the DNA of these cells that codes for a drug or a vaccine. If they take
the nucleus from one of these cells and transfer it to a cow egg, it could develop into a cow that makes the drug in its
milk. Since every cell in the cow would carry the drug gene, it could pass the gene to its offspring, creating a whole herd
of drug-producing cows. Even better, we could avoid the issue of the genetic reshuffling that happens during sexual
reproduction and simply clone our drug-producing cow.
Medicine, not food, may have more to gain from cloning
By Rick Barrett of the Journal Sentinel
Aug. 14, 2010
The cloning of animals may have come from agriculture, but its real promise may be in the lucrative field of medicine
rather than as food.
Genetically modified cows and goats can produce proteins in their milk that can be extracted as a drug component.
Cloning animals to create living drug factories could lower the costs of medicines used to save lives.
Examples include cows that pump pharmaceutical proteins and antibodies in their milk and blood; chickens that lay
drug-producing eggs; and pigs that grow human-ready organs. Making perfect copies of these animals, through cloning,
could speed up the drug-making process, according to scientists.
"Once you create a genetically engineered animal, you want to make copies," said David Andrews, director of animal
biotechnology at the Biotechnology Industry Organization, a trade association that represents 1,200 companies.
In Dane County, a now-closed biotech firm created cloned pigs that had human-friendly, transplantable organs.
The same firm, Infigen, created a herd of cloned cows with drug-making capabilities.
Infigen wanted to produce proteins for the treatment of hemophilia, an affliction that causes uncontrolled bleeding, and
Pompe's disease, a rare genetic disorder that can lead to muscle degeneration.
The science was proven, but the firm ran out of money and closed in 2004.
"Because we were breaking new ground, where the FDA approval process was not fully developed, investors were
hesitant. That became the stumbling block," said Michael Bishop, Infigen's former president.
"We knocked the science out and achieved some very amazing things," he said. "And the interesting thing is I don't think
the technology has advanced very much since then. As a matter of fact, I think Infigen enjoyed better success than
anybody else in the business."
Preventing blood clots
Currently, a Massachusetts biotech firm is using genetically engineered dairy goats to make a human protein that
prevents dangerous blood clots from forming. GTC Biotherapeutics extracts the protein from the goats' milk for a drug
that helps prevent strokes, pulmonary embolisms and other life-threatening conditions.
The FDA-approved drug, called ATryn, could be followed by other medicines made from the milk of genetically
engineered animals. Cloning would be an efficient way to create them, said Yann Echelard, GTC vice president of
corporate and technology development.
There are ways to do this without cloning, but it's a more predictable process, he said.
Now that the FDA has said it's safe to consume the milk and meat from cloned animals, it could help pave the way for
creating drugs.
"As scientists, we can do this stuff," said Mark Cook, an animal sciences professor at the University of WisconsinMadison.
"The big issues that came up were more regulatory than science based. Just to get a drug through FDA clearance can
take 10 to 15 years and cost a billion dollars."
A herd of 150 dairy goats could produce enough of a life-saving drug to meet the needs of thousands of people.
Not everyone agrees
But some people are wary of the use of genetically engineered animals, saying a mating between one escaped animal
and a natural one could trigger a chain of events that could contaminate a species.
"What we have learned from the genetic engineering of crops is that nature finds a way" to reproduce, said George
Kimbrell, an attorney with the Center for Food Safety, a nonprofit group focused on food issues.
"I am dubious, at best, of claims that if we produce these transgenic animals there are not going to be some accidental
escapes that will impact the environment and, potentially public health, through the food chain," Kimbrell said.
Genetic engineering raises animal cruelty questions, said Pete Shanks with the Center for Genetics and Society, a
nonprofit group that encourages responsible use of genetic technologies.