It has been a few years since cloning controversies dominated the news, but that may change now that scientists at Oregon Health & Science University claim to have overcome previous barriers, creating human embryonic stem cells (hESC) using the technique that leads to reproductive cloning.
In somatic cell nuclear transfer (SCNT), a donor cell is transferred to an egg cell whose nucleus has been removed, creating a human embryo. "Our finding offers new ways of generating stem cells for patients with dysfunctional or damaged tissues and organs," developmental and stem cell biologist Shoukhrat Mitalipov is quoted as saying in a press release that accompanied publication of the paper today in the journal Cell. "Such stem cells can regenerate and replace those damaged cells and tissues and alleviate diseases that affect millions of people," Mitalipov said.
Other researchers have used SCNT to generate only mouse and monkey embryonic stem cells, the press release said, but "those attempts failed to produce human SCNT embryos that could progress beyond the 8-cell stage, falling far short of the 150-cell blastocyst stage that could provide hESCs for clinical purposes."
Mitalipov and his team "transferred nuclei from human skin cells into the cytoplasm of human egg cells, generating blastocysts that gave rise to hESC colonies. The resulting hESCs resembled those derived from fertilized embryos, had no chromosomal abnormalities, showed normal gene activity, and were capable of turning into more specialized cell types that could be used for replacing damaged tissues."
Four hESC lines were derived from five eight-day-old blastocysts that were produced from one donor, the peer-reviewed ...1