London, January 18 : In what may be described as the first step towards using cloning techniques for biomedical research and therapy, a California-based company has successfully utilised adult human cells to produce cloned human blastocysts, an early stage of embryos.
Even though human blastocysts have been reported earlier also, Stemagen is the first company to produce them with male fibroblasts.
The company now needs to use such blastocysts to establish self-propagating lines of embryonic stem cells that would be genetically identical to a patient.
In 2004 and 2005, Korean researcher Woo Suk Hwang claimed that he had created cloned human blastocysts, and stem-cell lines from them. However, his results turned out to be fraudulent.
In May 2005, Miodrag Stojkovic and his colleagues at Newcastle University in the UK reported that three cloned embryos had made it to the blastocyst stage, but they could not produce a cell line. Besides, his group had used embryonic stem cells from discarded embryos from in vitro fertilization procedures, which were already in a flexible embryonic state.
Stojkovic, currently an associate editor at Stem Cells, has congratulated Stemagen for its achievement. He says that there is a "huge difference" between the company's work and what his own group had achieved.
Lead author Andrew French has revealed that the procedure to create human blastocysts involved fusing a woman's unfertilised egg with the genetic material of an adult man's skin cells. Their five successful blastocysts came from 20 to 30 eggs.
"We would have loved to go for the Holy Grail and get the stem-cell line, but we wanted to get this first step sorted out first," Nature magazine quoted him as saying.
Harvard stem-cell expert George Daley has hailed Stemagen's achievement, but he insists that the true test will be the derivation of cloned embryonic stem-cell lines.