Urge to Shift Away from Embryonic Stem

"Cloning pioneer urges shift away from embryonic stem cells," North County Times, by Bradley J. Fikes. December 1, 2011--Newer and safer forms of stem cell therapy will likely overtake research into the use of human embryonic stem cells, the scientist whose team cloned Dolly the sheep told his peers at a stem cell conference in La Jolla. Direct "reprogramming" of adult cells into the type needed for therapy is gradually becoming a reality, Ian Wilmut told an audience of several hundred at the Salk Institute at the annual Stem Cell Meeting on the Mesa. Such a feat was once thought impossible, but in recent years it has been demonstrated in at least two publications, he said. These reprogrammed cells appear likely to provide the anticipated benefits of embryonic stem cells without their risks, such as forming tumors. That risk will make government very reluctant to approve the use of cells derived from embryonic cells when a safer alternative is feasible, said Wilmut, whose team of researchers cloned Dolly the sheep nearly 15 years ago.

With its $3 billion stem cell program, California placed a big bet on the field known as regenerative medicine, hoping for a big payoff in improving health and boosting its large biotech industry. A major goal is to grow replacement tissues or organs for insulin-producing cells that can be transplanted into diabetics. Embryonic stem cells can grow into nearly any cell in the human body. Artificial embryonic stem cells, or so-called induced pluripotent stem cells, act in much the same way. This plastic quality attracts scientists, who foresee transforming them into nerve cells to repair brains in Parkinson's disease patients or insulin-producing cells for diabetics whose own insulin cells have been destroyed.

The use and value of embryonic stem cells is an intensely controversial issue. Many people object to their use because human embryos, which they consider human individuals, are killed to get the cells. Critics also point to the success of adult cells in approved therapies, while no therapy with embryonic stem cells has yet been approved. Only one treatment with embryonic stem cells is in clinical testing in people. And that company, Geron Corp., recently ended its involvement in what was described as a business decision.

Senior Fellow for Life Sciences, Center for Human Life and Bioethics, and CMDA Member David A. Prentice, PhD: "Ian Wilmut, Dolly’s 'daddy' (the cloner of Dolly the sheep), is making an assessment of the science in the field, not the ethics. But isn’t it interesting that the ethical science is also the successful science? Embryonic stem cells (ES cells) carry not only ethical baggage, relying on the destruction of young human life, but also have significant practical problems such as a tendency to tumor formation, which Wilmut points out. The newer induced pluripotent stem cells (iPS cells) avoid the ethical problems by genetically transforming a normal cell into one that behaves like an ES cell, without using embryos, eggs or cloning (somatic cell nuclear transfer). But, as Wilmut also notes, iPS cells have similar practical disadvantages regarding their tendency to form tumors, since iPS cell behavior mirrors that of ES cells.

"Wilmut, the cloning pioneer who previously moved away from cloning because the science was unworkable and impractical, is now advising researchers to move away from ES cells as well. When even a leading embryo researcher turns away from embryonic stem cells, you know the handwriting is on the wall. The 'direct reprogramming' technique that he mentions directly converts one normal cell type into another normal cell type, without going through any stem cell intermediate. While this newer technique for cell generation is a ways off from any clinical trial, there has been a recent torrent of published studies, including 10 papers in the last six months showing how to turn normal skin (including from human patients) into functional nerve cells. And of course, adult stem cells continue to successfully treat thousands of patients for dozens of conditions right now."

Resources
FAQ's on Embryonic Stem Cell Research
Stem Cell Fact Sheet