Scientists have used caffeine to achieve a stem cell breakthrough that many researchers thought impossible but which could lead to new therapies for many crippling diseases.
A US team used a human skin cell to create a cloned human embryo from which they were able to extract embryonic stem cells, a world first.
This technique, known as somatic cell nuclear transfer, or therapeutic cloning, is ethically controversial because it involves the production, and subsequent destruction, of a human embryo.
Its medical promise is that the embryonic stem cells obtained – which can turn into all cell types in the body for possible organ repair and transplant – are genetically matched to the person who donated the skin cell.
”This study is a breakthrough development that overcomes a major scientific hurdle with significant implications for potentially treating a range of diseases,” said Bryce Vissel, the head of the Neurodegeneration Research Program at the Garvan Institute of Medical Research.
Scientists, including Australian researchers, have spent years trying to create embryonic stems cells from cloned human embryos.
”Our finding offers new ways of generating stem cells for patients with dysfunctional or damaged tissues and organs,” said study leader Shoukhrat Mitalipov, of the Oregon Health & Science University. ”Such stem cells can regenerate and replace those damaged cells and tissues and alleviate diseases that affect millions of people.”
The chairman of stem cell sciences at the University of Melbourne, Martin Pera, said this new method also offered a unique approach to preventing inherited mitochondrial diseases, which cause debilitating degeneration in the brain and heart of affected individuals.
The discovery is published in the prestigious journal Cell.
Until now, researchers have only been able to grow human embryonic stem cells from surplus IVF embryos, which are not a genetic match with the recipient.
In 2007 scientists also developed methods to reprogram normal body cells into induced pluripotent stem cells, a process that won its inventors the 2012 Nobel prize. While this technique has reduced the need to grow stem cells from cloned human embryos, there have been concerns it may generate mutations in cells.
To obtain stem cells from a human embryo, the US team transferred the nuclei of a human skin cells into a human egg cell whose nucleus had been removed.
The cells grew into early-stage embryos, or blastocysts, that gave rise to human embryonic stem cells that were capable of transforming into other cell types.
The process has previously only been achieved in animal species such as mice and monkeys.
A South Korean research team led by Hwang Woo-suk published claims it had derived stem cell lines using the cloning technique in 2005, but their data was later found to be faked.
Other teams have produced cloned human embryos, but have failed to obtain embryonic stem cells from them. The US group overcame this problem by using high quality eggs, oocytes, grown in a solution containing caffeine, which protected parts of the cells activating prematurely
Ernst Wolvetang, an associate professor at the University of Queensland, said the method relies on women being willing to undergo super-ovulation and donate oocytes for such purposes.
”[That’s] a procedure that carries both inherent risks and its own socio-ethical concerns,” he said.
CSIRO’s stem cell research group leader, Andrew Laslett, said the long-term stability and safety of cloned embryo-derived stem cell lines was yet to be fully tested.
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