The use of human embryonic stem cells for research and therapeutic purposes sparked an ethical debate, but discussion has largely ignored the use of stem cells that are not derived from embryos.

Induced pluripotent stem cells (iPS) are mature cells taken from adults, such as skin cells, and transformed in the laboratory into pluripotent cells that can mature into a variety of different cell types. Researchers have generated more than 10 disease-specific iPS cell lines derived from patients with a variety of genetic diseases, such as diabetes and Parkinson’s disease.

Because iPS cells are derived from adult tissue, they seemingly sidestep the ethical issues of working with human embryos. A 2005 report by the President’s Council on Bioethics called iPS cells “ethically unproblematic and acceptable for use in humans.”

A recent paper argues that the potential uses of iPS cells might pose ethical issues to the donors.

iPS cells could be used to identify and test new therapeutics and might also themselves be used as part of cell replacement therapy. Because the technology is so new, there are many unknown applications – which is fine, because it looks like iPS cells can be grown in the laboratory indefinitely. Hence the ethical issue: People who donate their cells for iPS research might not have intended that their cells be used in a particular application.

The authors write: “First, if the perception that iPS research poses no ethical concerns is not corrected, there could be a backlash against iPS cells later. Second, the virtual genetic identity between iPS cells and donor cells raises particular concerns regarding respect for donors.”

U.S. regulations allow scientists to use biological materials for research without donor consent if the material is de-identified from the donor, which many of the pioneering iPS studies did. However, genome sequencing could allow donor’s cells to be re-identified. Moreover, donors might support use of their cells in research, but not in sensitive areas such as reproduction biology or transplantation.

The authors propose voluntary ethical guidelines, which include directing researchers to obtain additional permission from donors to use their iPS cells for potentially sensitive studies in reproduction biology or transplantation, and having researchers recontact donors to discuss future studies.

Source: “Obtaining Consent for Future Research with Induced Pluripotent Cells: Opportunities and Challenges” by Katriina Aalto-Setälä, Bruce R. Conklin and Bernard Lo, published in PLoS Biology on February 24, 2009.