“Only one in every million cells in the human bodythe stem cellsreally matter. Everything else is just a product of these,” said Dr. Stephen Emerson, the Francis C. Wood Professor of Medicine, chief of the Division of Hematology-Oncology, and associate director of clinical research for the Abramson Cancer Center.
A passionate advocate of stem-cell research, Emerson testified at a legistlative hearing held on Penn’s campus last September at which he called stem-cell biology the “Rosetta Stone” of modern health and disease treatment. “Discovering the language of stem cells, and the secrets of its translation, will make clear much that has been previously undecipherable,” he said. “How do you repair heart muscle damaged by heart attacks? Deliver the right stem-cell population to the damaged tissue, at the right time, with the right hormones to instruct the cells to form heart muscle. How do we prevent the crippling blindness of diabetes? Prevent blood-vessel stem cells from rushing headlong into the diabetic eye, forming new, chaotic blood vessels that bleed and clog.
“Cardiology, diabetes, obesity, cancer, blindness, osteoporosis, Alzheimer’s disease, even aging itself, are fundamentally all stem-cell processes.”
Residing in every tissue, from bone marrow to brain, pancreas to skin, plant to fungus, stem cells are the conductors in the complex orchestra that is the bodyof fruit flies, humans, and every species in between. They direct the fate of every other cell, spawning new healthy cells to replenish organisms or flipping the “on” switch to diseases like cancers, autoimmune disorders, Alzheimer’s, and osteoporosisand, perhaps, holding the key to treatments or cures for these and other now intractable conditions.
They are also, of course, the subject of one of the most intense ongoing bioethical and political debates in the United States, over the regulation of research using embryonic stem cells. First isolated in 1998 [“James Thomson and the Holy Grail,” Jan/Feb 2002], embryonic stem cells are harvested from the inner cell mass of the early-stage embryo, or blastocyst, at about five days old in a process that destroys the embryo.
Opponents of embryonic stem-cell research liken this to abortion and favor research focused on adult stem cells (which refers to cells isolated from any post-fetal tissue). However, while adult stem cells generally give rise to cells characteristic of their respective host tissues, embryonic stem cells are what is known as pluripotentable to develop into any type of tissue and therefore of much greater potential to understand and treat a wide range of diseases. “Adult stem cells are already committed, and we cannot easily twist them into different images,” says Dr. Meenhard Herlyn, who leads the Molecular and Cellular Oncogenesis Program at the Wister Institute and has used embryonic stem cells to study the molecular mechanisms of malignant melanoma.
In August 2001, President Bush approved federal funding for biomedical investigation using embryonic stem cellsbut only for studies involving cell lines that had already been established at the time. Many experts have argued that only a handful of these aging “approved” lines are actually viable, due to viruses and genetic mutations acquired over time.
“They’re too tired, not growing right, just burnt out!” says Dr. Arthur Caplan, the Emmanuel & Robert Hart Professor of Bioethics, chair of the Department of Medical Ethics, and director of the Center for Bioethics. Dr. John Wolfe, professor of pathobiology and pediatrics and director of Penn’s W.F. Goodman Center for Comparative Medical Genetics, considered using the established stem-cell lines for his researchaimed at correcting the genetic defects that cause certain inherited brain diseases in childrenbut later ruled them to be “inherently flawed.”
The federally sanctioned cell lines are, at best, a small group of mediocre selections to which every scientist has equal access. This is hardly inspiring for investigators, explains Dr. Glen Gaulton, professor of pathology/lab medicine and vice dean for research and research training at the medical school. “What’s the competitive advantage?” he asks. “As a researcher, you need to create a niche that separates you from others. That becomes difficult when you don’t have a unique tool to use in your work.”
Public support for embryonic stem-cell research appears to be running higha poll conducted this summer by the Opinion Research Council for the Coalition for the Advancement of Medical Research, a group that supports stem-cell research, found that 72 percent of respondents were in favor of allowing research on embryos that would otherwise be discarded. Another poll found 69 percent of Republican doctors favored expansion of federal funding to support research on such embryos.
Nevertheless, President Bush reaffirmed his position in July, exercising the first veto of his presidency to reject a bill that would have overturned his executive order and expanded federal support for embryonic stem-cell research involving the estimated 400,000 “spare” embyros in fertility clinics, the great majority of which will ultimately face destruction. Congress failed to override the vetoin the Senate, by just one voteand so the situation for federal funding remains the same as it has been since 2001.
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©2006 The Pennsylvania Gazette
Illustration by Anastasia Vasilakis
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