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Type 1 diabetes — the case
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stem cell research |
To counter the destruction of pancreatic beta cells in Type 1 diabetes, one possible solution is the transplantation of new beta cells, says Alan Cherrington, PhD, chair of the department of molecular physiology and biophysics at Vanderbilt University School of Medicine in Nashville, Tenn. But limits on the amount of available tissue and control of the human immune system are barriers to successful beta cell transplantation.
“There are not enough cadaveric islets available. It takes one of two cadavers to provide enough islets to transplant into an individual to effectively control their disease,” Cherrington says. “And we can’t control the immune system properly, so once we put this tissue in, there is a chance that the body will again attack and reject it.”
Stem cells might allow scientists to develop other sources of beta cells. The challenge, Cherrington says, is to convince these pluripotent cells to become beta cells.
“We need to learn more about the signals involved in creating that outcome,” he says. “By learning more about stem cells and how to make them go in a certain direction, the hope is that we can make enough tissue available to at least begin to approach solving the problem of supply. To the extent that we can have enough tissue available and to the extent that we then learn how to control the immune system in one way or another, then we can actually identify these people, give them islets, and prevent the rejection.”
According to Cherrington, new classes of drugs are being developed that seem to encourage new beta cells to form and old beta cells to divide. These drugs, which could slow the destruction or death of beta cells, probably will be on the market in about two years. A second-generation drug that would encourage cells to move from the precursor state into beta cells might be available in a decade, he says.
“How long it will take for us to be able to take embryonic cells and grow them in culture and tell them ‘I want you to become X’ — that’s probably a long time away, a minimum of 10 years,” Cherrington says. “In 10 years, we will have a better idea of how practical this is, but that’s a long-term solution, and I don’t think you can actually give that a date other than to say it’s a long-term solution.”
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Jean Peduzzi-Nelson, PhD, research associate professor at the University of Alabama at Birmingham, opposes embryonic stem cell research, but says it’s because adult stem cells are better for patients. They’re less apt to be rejected by the body and cause unwanted effects, such as tumors, she believes. The problem, in her view, is money and the quest for profits. She says the opportunity for patentable intellectual property in adult stem cell research isn’t available the way it is in embryonic stem cell research. For this reason, it’s unlikely that the “best treatment will reach the patient” because there’s no financial incentive needed for the major organizations to pursue it.
The public weighs in
A Harris Poll, released in mid-August, reports that the public supports stem cell research 6 to 1. According to the poll, large numbers of Republicans and Independents, not just Democrats, support the research.
Results from the nationwide survey of 2,242 adults interviewed online by Harris Interactive July 12-18 reveals:
- Those who believe that “using stem cells from human embryos for research comes too close to allowing scientists to play God” have fallen sharply from 40% in 2001 to only 19% now.
- The number of those who believe that “allowing any medical research using stem cells from human embryos should be forbidden because it is unethical and immoral” also has fallen sharply from 32% to 15% in the last three years.
- The level of opposition to stem cell research varies according to people’s religious beliefs. Those who describe themselves as “very religious” are much more likely to oppose stem cell research than those who are “not at all” or “not very” religious (23% vs. 4%). Born-again Christians are more likely to oppose it than are other Christians (21% vs. 9%); and Catholics are somewhat more likely to oppose it than Protestants (15% vs. 10%).
A highly charged issue
In the meantime, only research will uncover the true value of embryonic stem cells to cure or alter the course of disease, but the concept of their use holds promise. That hope has sent associations and several celebrities calling on the Bush’s administration to lift limits on embryonic stem cell research.
The groups represent patients with all sorts of chronic illnesses, such as diabetes, multiple sclerosis, and Parkinson’s disease and those with spinal cord trauma and other types of injuries.
The American Diabetes Association supports the opportunity for scientists in the U.S. to be able to conduct biomedical stem cell research as long as it’s consistent with the recommendations and guidelines of the National Bioethics Advisory Commission. That would include research involving the use of stem cells derived from adults, fetal tissue, or embryo stem cells, according to Cathy Tibbetts, RN, MPH, CDE, president of health care and education for the American Diabetes Association and a diabetes nurse educator at Innova Fair Oaks Hospital in Fairfax, Va.
Speaking from a personal perspective, Suzanne Murray, LVN, an ambulatory care nurse in gastroenterology in Murrieta, Calif., tells her own story of embryo adoption. She gave birth to Mary Elizabeth 15 months ago. The child has no genetic ties to Murray. “She was left over from her genetic family that had had in vitro fertilization. Those are the [stem cells] that you’re talking about regarding stem cell research — those are left over from IVF,” Murray says.
The embryonic adoption, through Nightlight Christian Adoptions in California, was like any other adoption, Murray says. She and her husband went through a full home study, and the genetic family chose them.
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