Stem Cells Save Babies

By Jeffrey Kluger

Almost lost in the hoopla over the stem cells cloned in South Korea was a stem-cell breakthrough closer to home--in more ways than one. Writing in the New England Journal of Medicine, researchers at Duke University Medical Center reported that infants born with a fatal nerve disorder have been helped--and perhaps even saved--by treatment with stem cells taken from the umbilical cords of healthy babies.

Of course, the stem cells used at Duke are not the kind that have caused so much anguish and debate in the U.S. Because these cells are taken not from embryos but from cord or placenta blood, they are both more developed and less versatile than embryonic stem cells. But they are also less controversial because no potential human lives are lost if the cells are destroyed. Yet they seem to have great potential for battling certain illnesses.

The target in this case was Krabbe's disease, a devastating enzyme disorder that prevents the nerve fibers in babies' brains from developing the myelin insulation they need, leading to blindness, deafness, cognitive deterioration and death before age 2. In the Duke study, 25 babies who tested positive for Krabbe's--some of them already displaying symptoms, others not--were dosed with umbilical-cord stem cells.

The bodies of all the babies accepted the grafts, a big advantage over rejection-prone bone-marrow cells, also used in transplants. But the results were uneven after that. More than half the kids who were already showing Krabbe's symptoms died from infections or other transplant complications.

In the other babies, however, remarkable things started to happen. The stem cells circulated uneventfully through most of the body. But when they landed in the sickened brain tissue, they appeared to know to go to work, restoring the enzyme that the babies lacked and causing affected nerve cells to regrow myelin insulation and healthy ones to keep what they had. "The cells go everywhere, but they seem to be more attracted to areas where there's injury," says neurodevelopmental pediatrician Maria Escolar, the study's lead author.

The surviving babies have had varying degrees of recovery, with the symptomatic ones remaining disabled but deteriorating more slowly and in some cases improving a bit. The mildly symptomatic or asymptomatic babies, though, did much, much better. "Our oldest survivor is 6 1/2," says Escolar. "She's now running, jumping and doing well in school." Best of all, since the stem cells take up residence in the brain and reproduce there like native cells, it appears to take just one dose of the therapy to achieve whatever recovery is possible.