| Pluripotent stem cells at a lab in Kyoto University in Kyoto, Japan. (AP)
New Delhi, Nov. 20: Scientists have for the first time coaxed human skin cells to slip into an embryonic state, bestowing them with the potential to turn into virtually any human cell or tissue.
The feat, announced today by researchers in Japan and the US, throws open a new route to produce human cells without the controversial use of embryos, exorcising associated ethical concerns.
A research team at the University of Wisconsin, Madison, genetically reprogrammed skin cells obtained from human newborn foreskin to turn them into cells indistinguishable from embryonic stem cells.
And scientists at Kyoto University and the Gladstone Institute of Cardiovascular Diseases, San Francisco, turned cells from the face of a woman into stem cells that also mimic embryonic stem cells.
Both teams reprogrammed skin cells by introducing special genes that turn the skin cells into what biologists call pluripotent stem cells with the potential to transform into brain cells, heart cells, liver cells, or any other type of human cells. Their findings will appear in the journals Cell and Science this week.
“We are now in a position to generate patient-specific stem cells without using human eggs or embryos,” said Shinya Yamanaka, the team leader at Kyoto University.
“These cells should be useful in understanding disease mechanisms, searching for safe and effective drugs, and treating patients with cell therapy,” Yamanaka said.
Scientists predict the technique’s simplicity could allow its rapid spread. “Any lab around the world with basic molecular biology and cell culture skills could derive these cells very easily,” Junying Yu, team leader at the University of Wisconsin told The Telegraph. “This will speed up the translation of this technology into clinics,” Yu said.
But the cells cannot be used for therapy yet because their production involved the use of viruses. “We have to be sure the cells are safe. We’ll have to find a way to avoid viruses,” Yamanaka said.
Scientists also caution that more study of the cells would be required to ensure that they do not differ from embryonic stem cells in unexpected ways. “It is hardly time to discontinue embryonic stem cell research,” said James Thomson, head of the Wisconsin laboratory.
Until now, scientists have been harvesting embryonic stem cells from human embryos discarded by invitro fertilisation clinics. This has drawn criticism from right-to-life activists and from women’s movements who have been opposed to the use of stimulating drugs in women who agree to donate eggs for embryo production.
“The new method could avoid many of the debates with the right-to-life community,” said R. Alta Charo, professor of bioethics at the University of Wisconsin.
The Wisconsin team started out with 600,000 cells from newborn foreskin and obtained 57 colonies of induced pluripotent stem cells. Yamanaka’s team began with 50,000 human cells and got 10 pluripotent stem cells. “The efficiency may appear low, but in a single 10-cm dish, you can get multiple cell lines,” Yamanaka said.
His team has shown that the cells can be turned into neurons (brain cells) and heart cells. In one experiment, after 12 days of dividing, the cells in a laboratory dish began to beat like a heart.
“This is an extremely important achievement,” said Deepak Srivastava, director of the Gladstone Institute.
Such transformed cells obtained from patients would lead to a better understanding of basic genetic mechanisms underlying diseases, Srivastava told The Telegraph.
“We’re now getting ready to produce such cells from patients with heart disease,” said Srivastava, who is in India this week to attend a conference and look for potential partners for research collaboration.
Using a patient’s own skin cells, the technique could be used to create cells customised to a patient. “Immune rejection should not be problem with these cells,” Thomson said.
Last year, Yamanaka’s team had shown that the insertion of the special genes into adult cells from mice could make them display features seen in embryonic stem cells