Stem cell research breakthrough

[Ross]

SCIENTISTS have created human embryos from slivers of skin, bringing closer the day when babies are cloned in the lab.

In experiments using techniques like those to make Dolly the sheep, they took cells from men's arms and legs and placed them into women's eggs.

The embryos lived for only five or six days, but they represent a key step in the quest for treatments for incurable diseases, from Alzheimer's to cancer.

Early-stage embryos have been made from human skin before, but the researchers say they have gone further.

The scientists, from the New York Stem Cell Foundation Laboratory, paid 16 young women for their eggs and took tiny samples from the skin of two men.

They placed the DNA from the skin cells inside the eggs and triggered them to grow and divide. In the case of Dolly, the eggs used were "hollowed-out" - their DNA had been removed.

But here, the technique worked properly only when the eggs' DNA was left in, showing there is something about it that is vital for the creation of life.

The embryos and the cells they contained were mutants, with three sets of DNA instead of the two we normally have - one from our mother and one from our father.

But the researchers are confident they can create healthy, cloned embryos with the required two sets of genetic material.

The aim is not to create cloned babies, but to extract stem cells - master cells capable of becoming any type of body tissue - from the embryos.

All stem cells gathered in this research were abnormal and not suitable for treating patients.

Researcher Dieter Egli said his work was inspired by the thought of being able to treat and even cure diseases.

Worn out hearts could be patched up, aged brains rejuvenated and diabetics freed from the need to take insulin, all thanks to stem cells.

Susan Solomon, chief executive officer of the not-for-profit organisation behind the research, said: "Cell replacement therapy would dramatically change the treatment of, and potentially even cure, debilitating diseases and injuries."

The extra genes in the embryos mean they do not, strictly speaking, qualify as clones.

But Josephine Quintavalle, of campaign group Comment on Reproductive Ethics, said: "Cloning is cloning however it is achieved.

''If women stopped selling their eggs, we could close down this unethical dead-end research once and for all."

http://www.heraldsun.com.au/news/more-news/cloned-lab-babies-a-step-closer/story-fn7x8me2-1226160588258

Ross

[Richard]

The embryos and the cells they contained were mutants, with three sets of DNA instead of the two we normally have - one from our mother and one from our father.

I would be very interested to know what the third set of DNA is. If not from the father or mother then what?

[Ross]

16 young women for their eggs and took tiny samples from the skin of two men.

They then placed the DNA from the skin cells inside the eggs and triggered them to grow and divide.




I think they used 2 skin cells from 2 men = 2 sets of DNA + Womans egg = 1 set of DNA. Total: 3 sets of DNA.

Thats how I read it anyway.


The extra genes in the embryos mean they do not, strictly speaking, qualify as clones.






To create human embryonic stem cells, researchers have taken human egg cells, cloned them – just as they did Dolly the sheep back in 1996 – and then reprogrammed them to become embryos.

And they work! These stem cells went on to form various tissues.

BUT, they’re a bit abnormal… they have 3 sets of chromosomes which means they’ll never be used to grow perfectly matched tissue for transplants.

However, at least we know the answer to the question: is it possible to make a cloned human embryo? “The clear answer of our paper to this is yes,” says study leader Dieter Egli of the New York Stem Cell Foundation Laboratory.

This cloning technique is called somatic cell nuclear transfer. It usually involves swapping DNA, but in this case, it involves adding the genome of an adult cell to the DNA of an egg.

(Somatic cells are all the ‘adult’ cells in our body that aren’t sex cells, which go on to become eggs or sperm. Somatic cells, have 2 sets of chromosomes, 1 from each parent. Sex cells have 1 total.)

The team ran a series of experiments using 270 eggs from 16 donors (who were each paid $8,000 like in vitro fertilization donors).

They injected both sets of chromosomes from adult skin cells into unfertilized eggs.
Then they got the introduced DNA to drive the eggs towards embryonic development.
Although the resulting embryos have an extra set of chromosomes, they still developed into blastocysts (the hollow ball of cells that forms around day 5 of our development).
From the blastocysts, the team went on to derive stem cells.

After 63 tries, they got 13 blastocysts and 2 stem cell lines. One carries the genome of a male who has type 1 diabetes, and the other of a healthy male adult.

This is the first conclusive evidence that a somatic cell genome transferred to a human embryo can be reprogrammed to a pluripotent state – with the ability to develop into all sorts of other cells in our body.

Okay, they’re not ‘true’ clones. Since the stem cells have 3 sets of chromosomes instead of the usual 2, the DNA doesn’t match the patient’s. (And our bodies really wouldn’t know what to do with 23 extra chromosomes.) With conventional cloning, the single set of chromosomes in the egg is usually removed… but in humans, the resulting cells stop developing early on and die.

To make this clinically relevant, they’ll need to get stem cells that are genetically matched to the donor. Egli’s group is trying to remove the egg’s DNA and create a viable embryo.

“This could allow us to create cells that are useful for transplantation for a variety of diseases without the problem of immunological rejection,” says lead author Scott Noggle.

Just how big of a deal is this? According to Nature News, this feat had at times been thought impossible, then inevitable, then completed, then incomplete and unfeasible

Ross