Embryonic obsession

Geron Corp. began the first FDA-approved embryonic stem cell (ESC) therapy last October, in patients with spinal cord injuries. Now a second company has begun its own clinical trials. Advanced Cell Technology partnered with a UCLA ophthalmologist to inject the eyes of two legally blind patients with about 50,000 embryonic stem cells apiece on July 12.

Given the novelty of the technology, though, it's too early to know whether either company's trials will avoid development of the tumors that ESC therapy sometimes causes-or whether the treatments will have any healing effect. Geron reports that its spinal cord treatment has proved safe so far, but hasn't said whether the patients' conditions improved.

Commenting on the trials, the head of the National Institutes of Health, Francis Collins-who is an evangelical Christian and an enthusiastic supporter of ESC research-said the public shouldn't set its hopes too high: "People need to be prepared for the fact that in this area, it's not going to be successful from day one."

I asked Kevin T. FitzGerald, a Jesuit and associate professor in the oncology department of Georgetown University Medical Center, why some stem cells run the risk of forming tumors. He said manipulating stem cells in a lab can cause unexpected changes: "You're taking a cell and kicking it in some way. And you're saying to it, 'Do something different.'"

Both ESCs and induced pluripotent stem cells have this problem-but FitzGerald prefers the latter cell type because deriving them doesn't require the embryo destruction inherent in ESC collection. To people who argue an embryo isn't sacrosanct until it implants in the uterus-a way of approving ESC research while disapproving abortion-FitzGerald answers that sanctity doesn't depend on location: "We send people into outer space. And if we don't put them in ships and give them oxygen, they'll die too. So when they get to outer space, does that mean they're no longer human beings?"

FitzGerald thinks induced pluripotent cells could have been reasonable alternatives to the recent ESC trials, but said that in terms of cures, adult stem cells are where reality lies. He pointed to the case of Yankees pitcher Bartolo Colon, who received stem-cell treatment in the Dominican Republic last year for a blown-out elbow and rotator cuff. Colon had been facing retirement due to his injuries, but the surgery, which used Colon's own stem cells, was so successful that the pitcher made a hailed comeback this year and threw a shutout in May.

"Interestingly, that research isn't being pursued [in the United States] as robustly," FitzGerald said, "because there's so much emphasis being put on doing human embryonic stem-cell research."

By the numbers

21

Maximum estimated diameter, in miles, of a new moon found circling Pluto-bringing the dwarf planet's total number of moons to four.

3

Number of feet the water level in the Dead Sea is dropping each year. Locals blame a heavily tapped Jordon River.

330

The length of miles, side to side, of an asteroid named Vesta that NASA's Dawn spacecraft will study for the next year. It's the agency's first mission orbiting an asteroid belt object.