Wednesday, July 11, 2007
Where Stem-Cell Research Thrives
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Stem cells are everywhere these days. On the national level, George W. Bush just vetoed another attempt by Congress to lift the restriction on federal funding. Locally, Massachusetts Governor Deval Patrick plans to encourage more stem cell research in the state. With the Harvard Stem Cell Institute (HSCI) doing cutting-edge work right here in Cambridge (it’s one of the few American centers for human embryonic stem cell research in existence), I spoke with Harvard and Joslin Diabetes Center stem cell biologist Amy Wagers about why we should care.
To be clear, Wagers explained, not all stem cell work is controversial. Stem cells are broadly classified into two different categories: adult and embryonic. Adult stem cells, the non-controversial ones, are able to regenerate their own type of cells or tissue. Blood stem cells are one example. Doctors can transplant blood stem cell-containing bone marrow into a person who has leukemia and repopulate his or her blood supply. Many, but not all, tissues in our body have stem cells like these.
The second type is the controversial one: embryonic stem cells. These stem cells don’t make just one type of tissue, they make all types. Scientists hope to someday use these stem cells to study complex diseases like diabetes or Parkinson’s, or grow up new, healthy tissue for people who are sick.
The ethical problem comes with the methods by which scientists want to make these embryonic stem cells. They can either take the cells from left-over embryos made during in vitro fertilization (IVF), or use a procedure called nuclear transfer. With nuclear transfer, a woman would donate an unfertilized egg – a long, sometimes difficult process – and scientists would replace the DNA-containing nucleus of the egg with a nucleus from another cell (for instance, a cell from someone with diabetes). The scientists would then let this new cell divide and grow for a few days until it becomes a blastocyst, smaller than the period at the end of this sentence, from which the stem cells could be extracted.
This is also sometimes referred to as human therapeutic cloning. The entire process has not yet been accomplished in humans, though it has been done in animals (think Dolly the sheep). According to the policies of the Bush administration, federal funding cannot be used for this sort of human research or for using new left-over IVF embryos because the embryo is destroyed in the process of extracting the stem cells.
“Traditionally, biomedical research has been funded by the federal government, the National Institutes of Health,” said Wagers. Without this money, research on embryonic stem cells is essentially stuck in the mud.
So Harvard decided to get un-stuck. HSCI is among a handful of groups across the country that use private funding to do their work. But it’s difficult. “In some cases, you have to set up duplicate labs, with duplicate equipment, make sure your graduate students are paid from the right sources in order to make sure you’re complying with federal guidelines,” Wagers explained.
Harvard has put together a consortium of people from its medical school, research institutions, divinity school, law school and business school to address the ethical and legal questions relevant to the embryonic stem cell issue. HSCI announced last summer that after two years of debate by eight different institutional review boards and stem cell oversight committees at six institutions (Harvard, Children’s Hospital Boston, Partners Health Care, Brigham and Women’s Hospital, Boston IVF and Columbia University), they have begun experiments to clone human embryos to make stem cells (they had already been working on other aspects of stem cell research).
Consortium members emphasize that they do not support reproductive cloning – implanting one of these cloned embryos into a woman to be grown into a baby. They hope only to study diseases or someday regenerate certain tissues. They also take great care in choosing and informing the women who will donate their eggs to the research.
In the past few years, HSCI scientists have been working on developing embryonic stem cell lines from leftover IVF embryos, as well as creating new, less ethically-divisive techniques for nuclear transfer.
“You get more by banding together than any one laboratory could support,” said Wagers. She hopes more funding will come soon. “With human embryonic stem cells it’s very early on, and a lot of that has to do with the complications involved in using human embryonic stem cells because [of] the issues of federal support for that research. It has probably slowed them down.”
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