The Proteus Effect: Stem Cells and Their Promise for Medicine by Ann B. Parson. Joseph Henry Press, $24.95, 301 pages.

The News & Observer

May 29, 2005

Divide and conquer

By PHILLIP MANNING


When Doug Melton’s son and daughter were diagnosed with juvenile diabetes, the chair of Harvard’s Molecular and Cellular Biology Department knew what to do. He found financing, jumped through some tricky legal hoops, and began to develop lines of embryonic stem cells. Getting permission to proceed was not easy because those stem cells come from IVF (in vitro fertilized) embryos, and our federal government discourages their use. Melton pursued stem-cell research because it offers the best hope for curing juvenile diabetes. Stem cells also offer hope to people with many other ailments, from deafness to Parkinson’s disease. But, as the current debate over a bill to fund expanded stem-cell research reveals, it also raises ethical questions. In her exhaustively researched book “The Proteus Effect,” Ann Parson explains stem-cell science and tells why some people are enthusiastic about using stem cells in medicine while others adamantly oppose it.

Stem cells are amazing. Each of us began life as a fertilized egg, a single stem cell. In a mere nine months, that cell divided, multiplied, and transformed itself into brain cells and muscle cells, cells for bones and cells for livers and cells for everything else. It is this protean quality, the ability to morph from one thing to another, that makes the promise of stem cells for medicine so great. Doug Melton, for instance, hopes one day to inject stem cells into his children and to coax those cells to change into the insulin-making pancreatic cells they lack. Melton knows that a stem-cell cure for juvenile diabetes is not imminent, but the potential is there.

Scientists have discovered stem cells in adults, but they are hard to isolate, difficult to culture (which means it’s hard to get them to multiply in a test tube), and can morph into only a few types of cells. Embryonic stem cells, on the other hand, are easy to isolate and can transform themselves into any type of cell. Furthermore, a supply of embryos is readily available.

These embryos exist because only about 25 percent of IVF eggs actually result in a live birth. This is not surprising; over 50 percent of normal pregnancies are spontaneously aborted, usually before the mother knows she is pregnant. To improve the odds, IVF clinics collect a dozen or more eggs from each wannabe mom. All the eggs are fertilized, but usually only three or so are inserted into the mother’s uterus. Unhealthy looking eggs are discarded, and the remaining ones are frozen and stored for later use if needed. Most often, the fertilized eggs are not needed. These eggs are doomed, set aside by parents who no longer want them. So, they languish in freezers, 400,000 of them in the United States alone, each a potential source of stem cells.

Parson tells the story of the first scientist to recognize the possibilities of using these eggs rather than letting them go to waste. His name was Ariff Bongso, a fertility specialist in Singapore. In 1993, he began growing embryos from fertilized eggs in his lab. The tiny embryos, only 5 days old and no bigger than the period at the end of this sentence, are called blastocysts. They consist of a hundred or so stem cells enclosed in a hollow ball. When Bongso dissolved the blastocyst wall, it left a batch of pure stem cells. He cultured the cells, aiming to produce huge numbers of them that could later be converted into tissue cells, brain cells, whatever a patient needed.

But science is rarely that simple. It took years to develop a line of long-living stem cells. (An embryonic stem-cell line is a batch of cells that originated from one embryo.) The problem was the cells would not stay stem cells; they kept changing into other cells, a process known as differentiation. When stem cells divide, they can produce more stem cells, or, guided by molecular signals, they can differentiate into other kinds of cells.

The key to using stem cells as medicines lies in controlling differentiation. No researcher wants to inject stem cells into a patient’s liver only to watch them turn into, say, skin cells. This is not a problem in a developing fetus; the stem cells seem to “know” what to do. As one neuroscientist put it, “Even the dumbest stem cell is smarter than the smartest scientist.” But scientists are getting smarter; they are learning how to induce stem cells to differentiate into the type of cell they want. A recent journal article, for example, explained how scientists turned embryonic stem cells into the pancreatic cells absent in children with juvenile diabetes.

Does this mean that Doug Melton's dream of a cure for his children’s disease is just around the corner? Hardly. Encouraging stem cells to turn into pancreatic cells in the lab is a far cry from getting them to do so in the body. More — much more — research is needed before the potential of stem cells as life-saving medicines is realized. However, the federal government is obstructing research because, Parson writes, “To many Pro-Lifers, Anti-Abortionists, and Born-Again Christians ... the ‘destruction’ of embryos was tantamount to homicide.”

That position might have moral consistency if stem cell opponents were moving to ban in vitro fertilization, which produces the surplus of fertilized eggs. As there is no broad movement to prevent infertile couples from conceiving children, what stem cell opponents are really arguing is that it is better to destroy those surplus eggs than to use them to create life. Despite this intellectual inconsistency, President Bush embraces the “homicide” rationale. He has not banned stem-cell research, but limited it. Earlier this month, he pledged to veto a bill that would provide federal funds for new stem-cell lines.

As federal money is the baker’s yeast of research, Bush’s policy has hampered stem-cell investigations in the United States. Not only does it slow research, but it also has a chilling effect on young scientists deciding whether to pursue stem-cell research. Doug Melton could gin up new stem-cell lines because he was an established scientist and able to find private funding, but that would be tougher for a rookie researcher.

In a recent magazine article, the Nobel Prize-winning biochemist Paul Berg complained about government interference in stem-cell research. “I couldn’t imagine,“ he said, ”how a bunch of guys sitting in Congress could sit there and say, ‘We’re offended by this technology, so therefore we are going to prohibit 290 million people in this country from having access to a therapy that could save their lives.’”