|The first step of SCNT involves the removal of nuclear genetic material from a human egg.--Courtesy of Cell, Tachibana et al.|
In what is being considered a major advancement in the field of stem cell research, a team at Oregon Health & Science University and the Oregon National Primate Research Center (ONPRC) has used a cloning method to successfully reprogram human skin cells into embryonic stem cells.
The new technique might be the push embryonic stem cell research needs to drive therapies toward the clinic, but it will likely be some time before the research could be applied to humans.
"I think one of the main roadblocks [in embryonic stem cell research] is that we still have to learn how to instruct these cells to become adult tissues," Shoukhrat Mitalipov, a senior scientist at ONPRC, said to FierceBiotechResearch in an interview.
To clone the cells, Mitalipov's team used somatic cell nuclear transfer, or SCNT, a method that involves transplanting the nucleus of a donor cell containing an individual's DNA into an egg cell that has had its nucleus removed. When the unfertilized egg develops, it produces embryos that are almost an exact genetic match to the donor individual. The benefit of creating near-matching stem cells, scientists believe, is that it would prevent people's bodies from rejecting the cells and causing disease or tumors.
Previously, researchers have only been able to generate mouse and monkey embryonic stem cells using this method because human egg cells proved to be more fragile to work with than eggs from other species. Mitalipov said most embryonic stem cell research has been in mouse models, which are simple and often not accurate in terms of translating research to bigger animals.
Building on a 2007 study that successfully transformed monkey skin cells into embryonic stem cells, Mitalipov and his team found that by prompting egg cells to stay in metaphase--the state in which genetic material aligns in the middle of the cell before cell division--the cells were able to develop and generate stem cells.
Just like normal embryonic stem cells, the newly produced clone cells were able to convert into different types of cells, including nerve cells, liver cells and heart cells. The new research was published online in the journal Cell May 15 and will be forthcoming in the print issue June 6.
Ever since their discovery, scientists have had high hopes for human embryonic stem cells, as their ability to develop into different types of specialized cells holds potential for treating a number of diseases and medical problems. The idea behind stem cell therapies is that they would replace cells lost or damaged through disease or injury, but so far, human embryonic stem cells have not yielded any cures or therapies to treat diseases.
The new cell-cloning method may have ethical as well as scientific implications, as the research might revive the debate about cloning humans--an area which the researchers say is not their focus.
- here's the study abstract
- read the statement from Oregon Health & Science University
Editor's Corner: Stem cell research advances in fits and starts