Mon, Feb 16, 2004 page16

• Reality tempers hope in stem cells

  Therapies derived fromstem cell research are probablya long way off, but patientsdon't like to hear that

  • By Gina Kolata / NY TIMES NEWS SERVICE
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  For four years, Richard Arvedon has been a passionate advocate for therapeutic cloning.

  The reason is his 6-year-old daughter, Emma. She has diabetes and is likely to develop serious complications within a decade, he said.

  

  A researcher at Seoul National University prepares to inject a somatic cell, shown on the monitor, into a bovine enucleated egg while watching through a microscope in Seoul, South Korea, Saturday. South Korean researchers who became the first in the world to successfully harvest stem cells from a cloned embryo won acclaim at home Friday for opening a new chapter in curing intractable diseases, but also were accused of demeaning human life.

  PHOTO: AP

  Arvedon's hope is that scientists will take Emma's cells, start the cloning process by making embryos that are genetically identical to her, extract stem cells and grow them into healthy pancreas cells that will not be rejected by her body.

  "I don't see anything else on the horizon that could help Emma in time," said Arvedon, a lawyer in Hartford, Connecticut.

  But scientists say that crusading patient advocates like Arvedon are desperate for a cure that they cannot provide.

  They are encouraged by the announcement last week that South Korean scientists had developed a line of cloned human embryonic stem cells, the universal cells that in theory can turn into any of the body's cells or tissues. In the face of powerful opposition to cloning of any kind from religious and political groups, these scientists say they desperately need friends like Arvedon.

  Yet scientists say the treatment he hopes for is a long way off. Their immediate goal is basic research into questions like the genetic basis of diseases. Even the term so often used, "therapeutic cloning," implies more than they are prepared to deliver.

  "At this stage," said Dr. Hans R. Schroeder, a professor of reproductive medicine at the University of Pennsylvania, "to say we are developing therapies, I would be very, very careful."

  In discussing the promise of stem cell research, some scientists say they weigh their words carefully. "We are mindful that this field has been overhyped," said Dr. Irving Weissman, who directs the stem cell institute at Stanford University. But when he tries to lower patients' expectations, "I feel like I'm shouting into the wind."

  Yet, says Dr. Lawrence S. B. Goldstein, a professor of cellular and molecular medicine at the University of California, San Diego, "People want you to try." He said, "You have to try. We owe no less to these folks."

  But history shows that developing even seemingly straightforward treatments can take many years, and many detours.

  In the early 1970s, scientists started talking about making "magic bullets" to treat cancer, hooking toxins to monoclonal antibodies and creating a sort of smart bomb that would zoom in on tumors and kill them.

  But it proved harder than most expected to find a therapy that worked. The first such drug, Mylotarg, made by Wyeth, was approved in 2000, for acute myelogenous leukemia, a rare but deadly form of the disease. Research leading to that drug began in 1981.

  And therapeutic cloning is far more complicated and the science far less understood. "It's definitely a baby field," said Dr. Denise Faustman, an associate professor of medicine at the Harvard Medical School.

  Scientists are excited by the promise for basic science. Dr. Weissman, of Stanford, likens the discovery of cloned embryonic stem cells to that of recombinant DNA.

  Dr. Goldstein, asked to speculate on the possibilities, spoke of cloning stem cells from an Alzheimer's patient. Those cells could be directed to turn into brain cells, and then analyzed to determine what goes wrong, when, and why. "We could study their biochemistry, we could test drugs on them," he said.

  For a disease like diabetes, says Dr. Inder M. Verma, a professor of molecular biology at the Salk Institute, pancreas cells made from the patient's cloned stem cells might have the same defects as the diseased cells. They could die, just as the original pancreas cells did. Dr. Faustman adds that if diabetes is caused when the immune system attacks the pancreas, as seems likely, even replacement cells might soon be attacked and destroyed.

  Cloning is an arduous process, and using it to create tailor-made replacement cells may prove impractical. Cloning uses human eggs, and that means finding young women who agree to be donors. Dr. John Gearhart, a stem cell expert at Johns Hopkins University, estimated that even if there were eggs and even if scientists knew how to efficiently get cloned stem cells that match a patient and to turn them into replacement cells, it would take months, perhaps a year, to make cells for an individual patient.

  But every scientist, even those whose work is only peripherally related to therapeutic cloning, hears from desperate patients who do not want to hear about the obstacles. Like Christopher Reeve, the paralyzed actor who has urged scientists to experiment on his cells, they do not want to wait.

  "Anything they think compromises therapy, they are angry about," Dr. Gearhart said. "It is sometimes very difficult with patients to get across to them this need for basic science, for fundamental discoveries, to enable us to derive appropriate therapies. They don't have much time left."

  Even scientists whose work is far removed from stem cells say they regularly hear from patients.

  "I try to reply to every one," Dr. Goldstein said. But he agonizes over what to say. "The goal is to engender hope but not promise what you can't deliver. Sometimes the brutal honesty of science is not what you want to be facing these people with."

  The flood of desperate patients can be overwhelming, some scientists find. Dr. Faustman published a paper on Nov. 14 in the journal Science on diabetes in mice, showing that spleen cells could turn into pancreas cells and cure diabetes under certain conditions. Immediately, the e-mail and phone calls began, and the pleading letters with photos of children.

  "I get 1,400 e-mails a week," she said. "It's unbelievable. `Why can't I volunteer?' I get prayers. They bring their kids into the lab. I have hired a person half-time just to answer the e-mails and the phone."

  Some patients say that no matter what they hear about the hurdles facing scientists, they have no choice but to remain hopeful.

  Arvedon, Emma's father, says he is not naive. "I know that even with the best scientists and the best aspirations and the most money, science can be fickle," he said. But he has to focus on a cure. Therapeutic cloning, or an understanding of diabetes that might come from it, "seems the most rational route."

  And advocacy groups know the power of passionate patients.

  Asked whether the Juvenile Diabetes Research Foundation would present scientists to Congress to talk about wanting to use cloned human embryonic stem cells to understand the genetic basis of diabetes or whether they would instead present a little girl with diabetes, Dr. Robert Goldstein, the foundation's chief medical officer, did not hesitate.

  "Are you kidding?" he asked. "You always go with the little girl. There's no choice."
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