Human Stem Cells Used To Create Part-Human Chimera From Other Species

Scientists are debating the ethical ramifications of placing human stem cells in the embryos of other animals in order to create chimera.

This past September, the National Institutes of Health (NIH) declared a moratorium on research that involves putting human stem cells into the embryos of other animals. The government issued the notice on September 23. In the notice they explain that it is important for funding to stop until they can deliberate future policy and consider the ethical ramifications of the research.

In short, the government is stalling funding while they attempt to answer the age-old question: “just because we can, does it mean we should?”

According to Carrie D. Wolinetz, an associate director of Science Policy working at the National Institutes of Health, the moratorium offers “a unique opportunity to take a deep breath… and consider whether any additional policies are needed to promote the responsible conduct of this promising science.”

The chimeras created by implanting human stem cells into non-human hosts are named after chimera from Greek mythology. In mythology, a chimera is a fire-breathing creature with a lion’s head, goat’s body, and a serpentine or dragon tail. When using human stem cells in other animals, a piece of those animals becomes human, making them a part-human hybrid.

What exactly are stem cells?

Adult stem cells are the kind of stem cells important to this story.

The National Institutes of Health goes into the exact description of what adult stem cells are on their web page.

“An adult stem cell is thought to be an undifferentiated cell, found among differentiated cells in a tissue or organ. The adult stem cell can renew itself and can differentiate to yield some or all of the major specialized cell types of the tissue or organ. The primary roles of adult stem cells in a living organism are to maintain and repair the tissue in which they are found.”

To make that a bit clearer, adult stem cells are cells found in the adult human body that are primarily used to help the body heal. The cells implanted into other animals to create chimera are human pluripotent stem cells. These are adult stem cells that have been genetically engineered to become embryonic stem cells. Embryonic stem cells can turn into almost any other cell in the human body: brain, sperm, kidney, lung, etc.

Why would anyone want to make chimera?

In the medical field, researchers believe that implanting human stem cells into other animals could give them a significant leg up when it comes to studying diseases that are difficult to study in human beings, such as Alzheimer’s, Lou Gehrig’s disease, strokes, and schizophrenia. The brain is still mostly a mystery to medical personnel and since the aforementioned diseases tend to affect patient communication, studying them in another living animal might aid in discovering how to help people affected by them.

Chimeras could also aid scientists in cancer and AIDS studies.

It is because of the significant uses of chimera in science that scientists are pushing back against the moratorium. The problem is that there’s a lot of things that could go wrong.

If they’re so useful, what’s the problem?

Inserting human stem cells in an animal embryo is not an exact science.

Stem cells introduced into the animal embryo could become brain cells, causing humanizing emotions and thoughts to develop in the creature. There is also the possibility that those stem cells could become part of the reproductive system.

If two chimera mice mated and one had a human egg and the other had a human sperm, there could be severe consequences. Not the least of which is the possibility of a human embryo being created by the mating.

Scientists insist that there are safe guards they could take against these possibilities, such as through use of sterilization.

Scientists against the moratorium are scheduled to testify at the National Institutes of Health headquarters in Bethesda, Maryland, next week.

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