Scientists in the United States say they have created human stem cells through cloning, breaking new ground in medical research but also stirring ethical concerns.
The study, first published on May 15 in a medical journal, was conducted by the Oregon National Primate Research Center (ONPRC).
Scientists used techniques similar to those that produced the cloned sheep Dolly in 1996, placing adult skin cells into a human egg previously stripped of its DNA.
So far researchers had been unable to create a cloned human embryo that is sufficiently developed to provide stem cells.
Stem cells -- which can be used to make any type of cell in the body -- hold much promise for medicine. They might eventually be able to treat various diseases and heal damage caused by injuries or, for instance, the damage caused by a heart attack.
Help Battle Diseases
Shoukhrat Mitalipov, a senior scientist at the ONPRC, said on May 16 that the breakthrough could eventually help battle degenerative diseases like Parkinson's and Alzheimer's.
“Parkinson's disease is caused by the dysfunction of very few types of cells. Basically, it's one type of neurons that are not producing enough chemicals, and in many patients these cells are actually gone," Mitalipov said. "They died off and there are no other cell types that can make this chemical. So now, in the laboratory, we can learn how to produce, for example, these neurons that would produce this chemical and transplant this into patients with this disease.”
Trials are also under way to treat various medical conditions with stem cells from donated embryos.
But the donated cells do not match the genetic makeup of patients and have so far been rejected.
Mitalipov -- an ethnic Uyghur born in Kazakhstan -- says therapeutic human cloning would solve this problem.
“We, in our laboratory, are interested in developing a new way of creating stem cells," he says, "but in this case the stem cells would be from a cell or skin cell derived from a patient, so that way the stem cells that [we] create would be compatible if we transplant these tissues back into [the] patient.”
But critics say experimenting on human embryos, even if they were created in a laboratory, is unethical.
Despite scientists’ claims that embryos created from this new technique could never become viable human beings, there are fears that therapeutic cloning will pave the way for producing live babies.
Critics of the new technique say other sources of stem cells may be cheaper and less controversial.
Researchers are already able to convert skin cells into stem cells using proteins.
It is still unclear, however, whether stem cells obtained this way are suitable for medical purposes.