New Stem Cell Technique Eliminates Risks and Ethical Concerns

June 03, 2009

Adriana Bobinchock

Belmont, MA - Researchers at Harvard-affiliated McLean Hospital have been able to create stem cells out of human skin cells using a process that eliminates the risk of cancer associated with other methods.

The research team, headed by Kwang Soo Kim, MD, director of the Molecular Neurobiology Laboratory at McLean, used proteins rather than genes or viruses to reprogram the cells, eliminating the risk of cancers or other abnormalities developing in the reprogrammed cells associated with the use of genes or viruses.

The study, published in Cell Stem Cell, is available online at (DOI: 10.1016/j.stem.2009.05.005).

"We are very excited about this progress after many years of struggle," said Kim, also an associate professor of neuroscience at Harvard Medical School. "This has opened up some exciting opportunities. I believe our work has solved some very fundamental issues in stem cell research and will lead to therapeutic applications in the near future."

The technique could result in the availability of the first clinic-ready human induced pluripotent (iPS) stem cells. After some refinement of the technique, the stem cells could be used to develop treatments for a variety of illnesses, including Alzheimer's, Kim said.

"We showed proof of principal that we can generate potentially safe human iPS cells using this new method," he said.

The next step will be to refine the technique to make it quicker and more efficient and investigate the differentiation of these iPS cells to many different cell types, he said.

The method of creating the stem cells using a patient's own skin cells also eliminates the problem of immune rejection that is associated with using embryonic stem cells, according to Kim. It also avoids the ethical questions that have swirled around embryonic stem cell research.

Publication of the paper follows one published a month earlier by Sheng Ding of the Scripps Research Institute that reported the first DNA- free method for obtaining iPS stem cells. It used proteins taken from bacteria as well as chemical additives and was done using mice cells, not human cells.

Both papers follow publication of papers in 2006 and 2007 by Shinya Yamanaka of Kyoto University. Yamanaka was the first to successfully reprogram skin cells into iPS cells, first in mouse cells and later in human cells. However, the technique used viruses to deliver four genes into the cells to do the reprogramming needed to turn them into blank slates.

Kim's team used companion proteins to the genes utilized by Yamanaka, attaching peptides to them to allow them to enter the skin cells.

"The proteins do not touch the DNA sequence and thus maintain them intact and this new technology is now considered to be an important milestone in stem cell research and clinical application for the ultimate goal of customized cell therapy," he said.

As a result, the stem cells created by the process are more feasible for clinical applications or for biological studies, he said.

Once the technique is optimized so that cells are created more efficiently and it is proven to be safe, "we'll be ready for clinical applications," he added.

While that still could be years away, "we have made it much closer," he said.

Kim's team included members from McLean, and those at Stem Cell and Regeneration Medicine International in Worcester, Mass., and the CHA Stem Cell Institute in Korea.

Kim is also affiliated with the Harvard Stem Cell Institute and the CHA Stem Cell Institute.

The work was supported by grants from the National Institutes of Health and international grants from the Dongyang group and CHA University.

McLean Hospital is the largest psychiatric clinical care, teaching and research facility of Harvard Medical School, an affiliate of Massachusetts General Hospital and a member of Partners HealthCare. For more information about McLean Hospital, visit

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