Debate continues over human embryonic stem cell research, but medical breakthroughs have been made using adult stem cells and other body cells.
Researchers treated 250 diabetics with islet cells from the pancreases of deceased human donors, and more than 80 percent were able to stop their insulin shots for more than a year, the Atlanta Journal-Constitution reported in June.
Adult bone marrow stem cells have been shown to help repair muscle damage, say two research groups that published animal studies in the December issue of Nature.
These cells also have shown promise in treating human heart patients. In one example, 14 patients showed significant improvement in heart function for several months after receiving injections of their own bone marrow stem cells, said a study published in Circulation in March.
“It’s very encouraging,” said Dr. James T. Willerson, chief of cardiology at the Texas Heart Institute and one of the doctors who conducted the study. He noted a “significant improvement in blood flow” in the areas of the heart where the stem cells were injected.
Adult bone marrow stem cells also were shown to help heal three patients suffering from chronic skin wounds, said a study in the April issue of Archives of Dermatology.
Toronto scientists are taking stem cells from the eye, using them to generate new cells in a lab and transplanting the new cells into damaged eyes, hoping to improve function, Canada’s Edmonton Journal reported Nov. 30.
Five Parkinson’s disease patients in another study received brain injections of a natural body chemical known as glial cell-line derived neurotrophic factor (GDNF). Symptoms improved in all five after three months. One year later, they had experienced a 61 percent improvement in their ability to perform daily activities, researchers said in the May issue of Nature Medicine. Three of the patients regained their senses of taste and smell.
Some say these advancements show that adult stem cells and other types of body cells hold more promise for medical treatments then do human embryonic stem cells.
Embryonic stem cell research has shown positive results in animals but hasn’t produced successful human studies. No one has been able to clone human embryos and grow them to the stage where their stem cells can be extracted for research.
“I think what we’re going to see is that the science is going to continue to show success with the adult stem cells, whereas we have seen no results in patients with embryonic stem cells, precious little in animals with embryonic, and frankly, negative results in animals with cloning,” said David Prentice, a cell biologist and professor at Indiana State University, who noted medical problems in Dolly the sheep and other cloned animals.
“Even aside from the serious moral issues, embryonic stem cells are very far away from helping any human patient,” said Richard Doerflinger, deputy director of the Secretariat for Pro-Life Activities at the U.S. Conference of Catholic Bishops. “Meanwhile, non-embryonic cell therapies are producing new advances literally every week. They are already in clinical trials to help patients with Parkinson’s, [multiple sclerosis], diabetes, immune deficiencies, spinal cord injury, et cetera.”
Defenders of embryonic stem cell use say progress has been hindered by the Bush administration’s policy to limit federal funding of such research to certain existing embryonic stem cell lines.
“The president’s policy … is delaying cures,” said Sean Tipton, vice president of communications for the Coalition for the Advancement of Medical Research, a group of universities, patient and scientific organizations pushing for embryonic stem cell research, including the cloning of human embryos to produce stem cells for medical research.