March 9, 2009

Lifting of Stem Cell Ban Affects UCSF and Research Community

By Jeffrey Norris Through executive order, President Barack Obama today lifted the Bush administration ban on the use of federal funds to conduct research on human embryonic stem cells. UCSF Chancellor J. Michael Bishop, MD, was among prominent scientists to witness Obama signing the executive order at the White House. Read that story here. Bush initiated the ban in response to moral concerns surrounding the destruction of human embryos to create stem cell lines. These embryonic stem cell lines can be grown in the laboratory indefinitely. They serve as the basis for research explorations that are expected to lead to new types of disease treatment. The new field is called regeneration medicine because the goal is to replace cells that have died or no longer function normally due to disease or injury. The Bush ban drove some states, including California, to offer their own support for embryonic stem cell research. The California Institute for Regenerative Medicine (CIRM) was created through voter approval with state funding. Obama’s executive order now opens the way for the federal National Institutes of Health (NIH) to sponsor certain types of stem cell research. Obama also directed the agency to develop guidelines regarding how researchers should properly obtain human embryonic cells.

Dismantling Barriers

At UCSF, the change announced today lessens the need for research teams to maintain separate and redundant laboratories for allowable federal research and for embryonic stem cell research that is not federally funded. “We will be able to literally and figuratively take down the barriers and create a continuous human embryonic stem cell research laboratory environment,” says Arnold Kriegstein, MD, PhD, director of the Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research at UCSF. “Moreover, investigators in existing laboratories scattered on both the Parnassus and Mission Bay campuses will now be able to freely bring human embryonic stem cell lines – including new ones created at UCSF – into their NIH-funded laboratories,” Kriegstein says. The new executive order frees researchers to use federal funds to study stem cell lines that were not previously approved for federally funded studies. “I will now be applying to the NIH for a project involving human embryonic stem cell lines and a strategy for identifying stem cells that generate specific types of nerve cells,” Kriegstein says. “I would not have proposed this experimental approach using the older, federally approved lines.” However, while the new executive order allows researchers to use federal funds to work on human embryonic stem cell lines, it does nothing to overturn an earlier act of Congress that still limits the use of federal funds for research. The so-called Dickey-Wicker Amendment prohibits the use of federal money for research that results in the destruction of human embryos, which is required to create new human embryonic stem cell lines in the first place. UCSF researcher Susan Fisher, PhD, professor of cell and tissue biology, is at the vanguard of those who generate new human embryonic stem cell lines and make them available for the broader research community. “There is practicality, and there is reality,” Fisher says. “From a practical point of view, the executive order reducing restrictions on human embryonic stem cell research is probably at the outer boundaries of what the American public currently considers acceptable. But my realistic assessment is that – for groups like ours, who primarily work with human embryos – very little will change because the study of human embryology and the derivation of new lines will still be ineligible for government funding.” Kriegstein adds, “Because of the Dickey-Wicker Amendment, the NIH will not fund the derivation of new cell lines. However, at UCSF, we may be able to use CIRM funds to derive new lines, and both CIRM and NIH funds to study them.”

Exploring New Approaches

While the destruction of unwanted human embryos obtained from fertilization clinics is regarded by some people as destroying human lives, cells obtained from these embryos have unique value among biomedical researchers who are exploring new approaches. They hope such approaches will lead to new treatments for deadly and debilitating diseases that strike both children and adults. A fertilized human egg – a single cell – becomes a structure with an outer layer and an inner cell mass. The inner cells are the source of embryonic stem cells. These cells have the potential to become any type of cell in the body. Researchers are seeking to grow stem cells and to shape the functional fate of specialized stem cell progeny. The goal is to create ample amounts of specialized cells for the development of new treatments, based on the regeneration of tissue lost to disease. Some opponents of lifting the ban have argued that recent advances in deriving highly potent stem cells from adult cells make human embryonic stem cell research unnecessary. Shinya Yamanaka, MD, PhD, now a UCSF faculty member, pioneered research to turn back the development programming in adult skin cells, making them more similar to embryonic stem cells in their potential to give rise to the myriad types of cells that populate tissues throughout the body. These cells are called induced pluripotent stem cells. A significant amount of research talent and funding has moved into this new area of stem cell research. Even so, Kriegstein and Fisher maintain that both adult and embryonic stem cell research is vital. “It is likely that the first cell-based therapies will use newer human embryonic stem cell lines,” Kriegstein says. “The induced pluripotent stem cells – despite their attractive advantages in terms of immune rejection – are more problematic in terms of safety, and will likely take longer to enter the clinic.” The lifting of the ban, Kriegstein adds, “can only accelerate the research and speed advances in treatment, particularly because NIH-funded investigators who have up to now worked on mouse cells, or who are beginning to use human induced pluripotent stem cells, will now be free to make comparisons with the latest human embryonic cell lines. Embryonic stem cell lines remain the gold standard against which other stem cell lines need to be compared, even if induced pluripotent stem cells eventually prove to be better for certain therapeutic or diagnostic purposes.” Fisher adds, “Until we have developed a blueprint for devising human embryonic stem cell-based therapies to cure human diseases, there is no reason to abandon one approach in favor of another. History has taught us that multiple approaches to tough biomedical problems are more likely to bear fruit. It is likely that both avenues of research will yield complementary information.” Image: Samantha Zeitlin, 2006 CIRM fellow

Dismantling Barriers

Exploring New Approaches

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