New Stem-Cell Breakthrough Rewrites the Ethical Debate

A new stem cell breakthrough will likely accelerate promising new avenues of research. Acclaimed stem cell researcher Shinya Yamanaka, MD, PhD, has reported that he and his Kyoto University colleagues have successfully reprogrammed human adult cells to function like pluripotent embryonic stem cells. This discovery may end up nullifying the majority of the ethical debates, controversy, and subsequent restrictions regarding stem cells research.

Last year, Yamanaka, who is also a senior investigator at the Gladstone Institute of Cardiovascular Disease (GICD), reported that he and his Kyoto colleagues had reprogrammed mouse skin cells into pluripotent stem cells, laying the foundation to apply this methodology in human cells.

In this earlier work, published in Cell, Yamanaka and his colleagues identified four genetic factors that resulted in the reprogramming of adult mouse cells into induced pluripotent stem (iPS) cells capable of developing into any kind of cell. This summer, he reported in Nature that these iPS cells could even form a new mouse, making them functionally the same as embyonic stem cells. According to the new research, those same genetic factors used with human adult cells resulted in iPS cells which are nearly indistinguishable from human embryonic stem cells.

“The rapid application of this approach to human cells has dramatically changed the landscape of stem cell science,” said GICD Director Deepak Srivastava, MD. “Dr. Yamanaka's work is monumental in its importance to the field of stem cell science and its potential impact on our ability to accelerate the benefits of this technology to the bedside. Not only does this discovery enable more research, it offers a new pathway to apply the benefits of stem cells to human disease.”

This exciting advancement is redefining the political and ethical areana of the stem-cell controversy say leading bioethicists. R. Alta Charo, a UW-Madison professor of law and bioethics, confirms the scientific finding will likely have far-reaching effects on the social dimensions of the ongoing controversy over embryonic stem cell research.

"This is a method for creating a stem cell line without ever having to work through, at any stage, an entity that is a viable embryo," Charo says. "Therefore, you manage to avoid many of those debates with the right-to life community."

The research also alters the debates surrounding both human embryonic stem cell research and somatic cell nuclear transfer cloning. For ordinary embryonic stem cell research, it offers a means of obtaining pluripotent cell lines from a non-embryonic source. For cloning research, it offers a means to make customized, pluripotent cell lines without having to create an intermediate embryo that is a "clone" of an adult person, she says.

Charo says the discovery could remove objections from critics on both the right and left wings of the political spectrum.

To derive embryonic stem cells, it is necessary to remove critical cells from an embryo, resulting in its destruction. That triggers opposition from right-to-life critics of the research, who cite moral and ethical concerns. The research has also generated opposition from some members of the women's movement who object the use of stimulating drugs in women who agree to donate eggs for cloning research aimed at creating specialized embryonic stem cell lines.

The latest findings have the potential to render both of those objections moot, since the research showed that introducing four genes into cells derived from skin cells, called human fibroblasts, resulted in cells that essentially share all the features of embryonic stem cells - but without using or destroying embryos. But stem cell researchers are wary that the new discovery could make embryonic stem cell research even more complicated. Even Yamanaka warns that embryonic stem cell research shouldn’t be thrown out the window in light of his recent discovery. The human embryonic stem cells is still considered the “gold standard” against which all alternative sources of human pluripotent stem cells are tested.

“We are still a long way from finding cures or therapies from stem cells and we don’t know what processes will be effective,” Yamanaka said.

Even so, the new finding is likely to open up new avenues of research that are currently eligible for federal funding. Recently, the White House directed the National Institutes of Health to emphasize the funding of research that examines alternative means for obtaining pluripotent cell lines whose usefulness is comparable to that of human embryonic stem cells. This groundbreaking research will be reported in the journal Cell.

Posted by Rebecca Sato

• This post was adapted from news releases issued by Gladstone Institute of Cardiovascular Disease and Eurekalert.