Cloning: a fertile future?
Belgian scientists have unveiled a new cloning technique, but how much hope does it offer for infertile couples? Aaron Gray-Block reports.
These slides show the development of the embryo
The Ghent University academics said at a fertility clinic in Copenhagen they had cloned the first human embryos from immature eggs grown in the laboratory.
Prior to this achievement, scientists had only used donated mature eggs, which are in short supply.
Scientist Bjorn Heindryckx said the cloned embryos were made by filling immature female eggs with the hereditary material from mature cells of another person.
The success of the technique demonstrates that immature eggs not used in fertility treatments can be grown in the laboratory and used to create embryos.
These embryos can be used for stem cell research and therapeutic cloning to treat disease.
South Korean lead
In February 2004, South Korean scientists scored a world first when they reported cloning a human embryo.
They removed the hereditary material from the eggs of fertile women and refilled these cells with the DNA of an adult cell taken from the same donating woman.
The scientists then allowed the embryos to grow from these cells to the blastocyst stage, at which point stem cells can be removed. These embryos had just one genetic parent.
What the Ghent academics did was more difficult.
They made embryos from immature egg cells. After 'emptying' the egg cells, the scientists re-filled the eggs with the DNA in an adult cell from a different person.
The DNA of an adult cell was inserted into an immature egg cell
This is important because mature egg cells are in short supply. European regulations prevent the removal of immature cells from healthy women for the purposes of research.
However, when women undergo fertility treatments, a few immature egg cells are accidentally taken along with the mature cells.
Because they don't mature easily in a laboratory, immature cells are not usually used in IVF treatments. This 'over supply' is then used in cloning studies.
The cloned embryos formed from the immature eggs grew to the 8-16 cell stage — too early to extract stem cells, the Belgian scientists said.
They will keep trying to get the cloned embryos to the blastocyst stage, when stem cells can be removed.
Stem cells can grow into any type of cell in the body. Scientists are trying to create human embryos to obtain stem cells for therapeutic or 'repair' cloning.
The Belgian scientists hope the research will lead to treatments for infertile patients.
"Our final goal is to use human therapeutic cloning for infertility treatment by creating artificial eggs and sperm for patients who are infertile because of absence or premature loss of eggs or sperm," Heindryckx said.
Sheffield University academic Behrouz Aflatoonian suggested at the Copenhagen fertility conference that such a technique is feasible.
He removed stem cells from embryo cells left over from an IVF procedure, which were remodeled into what appeared to be the precursors of egg and sperm cells.
The Belgian embryo cloning success comes just two days after a British academic sparked alarm by warning infertility could double in Europe over the next decade.
Cloning technology: hope for infertile couples?
As more and more women opt to have a child at an older age, Ledger said women should be given the chance take time out from their careers to have a baby at a younger age when they are more fertile.
Ledger also warned that obesity and sex infections, particularly among the young, are leading to rising infertility rates.
However, Belgian researcher Heindryckx told Expatica his res