Adult Stem Cells, and Other Sources, Showing Promise

Published: March 6, 2004  |  Source: zenit.org
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SAN FRANCISCO, California, MARCH 6, 2004 (Zenit.org).- As debates continue over cloning and use of human embryos, progress is being made in the far less ethically objectionable field of research with adult stem cells.

A case in point is a study published in the scientific journal Nature. Researchers at the University of California at San Francisco have discovered a mysterious type of stem cell found in the brain, the San Francisco Chronicle reported Feb. 19.

The scientists based their study on tissues from 45 autopsied brains and from 65 patients who had undergone surgery. The report noted that the research lays new ground for understanding the fundamental biology of stem cells in the adult brain. The hope is that these cells might someday be used for treating brain injury, strokes or neurodegenerative diseases such as Parkinson’s.

However, in a commentary published by Nature, Yale University neurobiologist Pasko Rakic noted that scientists were still a long way from unraveling the circuitry that shapes the fate of the brain’s stem cells.

The preceding months saw a constant stream of announcements on research involving adult stem cells. USA Today on Sept. 24 reported, for instance, on research published in the “Proceedings of the National Academy of Sciences” regarding stem cells in monkeys.

The investigation involved generating stem cells from an unfertilized monkey egg by stimulating it to divide and create a tiny ball of tissue. Scientists speculated that using unfertilized eggs as source material for stem cells may be less controversial because the cell mass could not become a fetus.

“The key is these cells were created without the union of a male and female, so in essence it is a new way of making stem cells without destroying viable embryos,” said Kent Vrana of Wake Forest University Baptist Medical Center.

Heart problems treated

On Oct. 10 the Sydney Morning Herald reported on work being carried out by researchers at Melbourne University and Columbia University in New York involving adult stem cells. The research involves pushing stem cells from the bone marrow into the bloodstream and has shown positive results already with five patients in treating heart problems.

Once the stem cells are in the bloodstream, scientists isolate them from surrounding cells. This process yields a greater concentration of stem cells, which can then be injected back into the patient’s bloodstream, where they make their way to the heart to fix, the researchers believe, damaged cells.

Dr. Andrew Boyle, from Melbourne’s St. Vincent’s Hospital, cautioned that the treatment was still in the early stages. However, animal studies had shown that these cells were capable of growing new blood vessels, and arresting damage to the muscles caused by a heart attack, he noted.

More positive news came from research in Brazil. BBC on Nov. 17 reported that scientists from the University of São Paulo said they have successfully restored feeling to patients paralyzed for at least two years. They said 12 out of 30 spinal cord patients responded to electrical stimulation of their paralyzed limbs.

The researchers harvested stem cells from the patients’ blood, and reintroduced them into the artery supplying the area that was damaged.

Lead researcher Tarciscio Barros said: “Two to six months after treatment, we found that patients were showing signs of responding to tests.”

On Dec. 2 the Chicago Tribune reported on efforts by scientists at the University of Illinois at Chicago who succeeded for the first time in growing a full-size copy of a human jaw joint complete with bone and cartilage.

The result was accomplished by coaxing rat stem cells taken from bone marrow to multiply into the jaw structure. The goal is to create living tissue joints and organs that integrate with existing organs and bones and function like natural body parts, said Jeremy Mao, director of the school’s tissue-engineering laboratory. Mao cautioned, however, that the work is preliminary and that much more research needs to be done before the new technology can be brought to patients.

These reports are only a small sample of the positive results being obtained with adult stem cells, Wesley Smith observed in a Dec. 3 commentary written for the Daily Standard. Smith said a list outlining successful experiments with adult stem cells could go on for pages. He lamented, however, that the mainstream media often ignore or underemphasize adult stem cell research successes.

Nevertheless, the Washington Post recommended caution in this field. The newspaper reported Oct. 13 on a study published by a neurobiologist from the University of California in San Francisco, Arturo Alvarez-Buylla, who warned that some scientists may have inadvertently overstated the positive results from earlier studies involving adult stem cells taken from bone marrow.

The results, published in the journal Nature, led the scientists to recommend continuing research using stem cells taken from embryos. Yet, the Post noted, this does not deal with the ethical objections “that no amount of therapeutic benefit can justify the destruction of a human embryo.” Moreover, Alvarez-Buylla’s study only dealt with earlier experiments and not with more recent data that have shown success with adult stem cells.

Umbilical cord blood

Another promising source of cells for medical treatment comes from blood contained in umbilical cords. Last year marked the 15th anniversary since the first experiments with these cells. In 1988 in Paris, a boy with a life-threatening form of anemia was saved by a few ounces of blood from his newborn sister’s umbilical cord, the Philadelphia Inquirer noted July 21.

Cord blood transplants are still relatively rare and experimental, although there have been around 2,500 worldwide, the article said. Hopes that this method may be used more widely in the future have led an increasing number of parents to pay commercial storage companies to preserve their newborns’ cord blood.

At the time of the article these companies had accumulated over 100,000 cord blood specimens. Preserving these specimens is costly, with an initial payment of $1,000, plus $100 a year.

Cord blood is medically valuable because, like bone marrow, it is rich in blood stem cells, the precursors of red blood cells, infection-fighting white blood cells, and clot-forming platelets.

A patient whose own blood cells have been destroyed by high-dose chemotherapy and radiation can be given a transplant — actually, it’s more like a transfusion — of stem cell-laden bone marrow or cord blood to resupply his entire blood and immune systems.

Hopes regarding umbilical cord blood received a stimulus when researchers at Duke University reported they used stem cells from this source to treat children with diseases affecting the heart, liver and brain. The doctors told a conference that cells taken from umbilical cord blood can turn into healthy heart cells, for instance, and repair damaged tissue, BBC reported Feb. 17. Much work remains to be done in this area, but preliminary results show that ethically acceptable methods are available.