Immortal cells

    Fessler (left) and Kessler (right) in front of neural stem cells grown as neurospheres. 40x magnification. Photo by Gus Wezerek / North by Northwestern. Neurosphere image courtesy of Maya Srikanth, Kessler Lab.

    Emergency rooms all over Chicago are waiting for a patient who has suffered just the right kind of spinal cord injury. Doctors hope to offer an experimental treatment — the first created from human embryonic stem cells — that might reverse incurable paralysis.

    Northwestern Memorial Hospital is the lead site of a trial to test the safety of the new therapy, which grows completely new spinal cord tissue in paralyzed patients.

    Richard Fessler, professor of neurological surgery at Northwestern’s Feinberg School of Medicine, performed the nation’s first transplant of a human embryonic spinal cord — not stem cells — in 1997. He’s the trial’s lead national investigator.

    “It’s exciting, and intimidating,” Fessler says. “Curing paralysis has got to be one of the most exciting things one could ever imagine doing, tantamount to curing cancer. It’s intimidating for that same reason, because it is so important.”

    Because human embryonic stem cells can replicate infinitely, they’re immortal in the right conditions. But these microscopic blank slates, which can grow into more than 200 types of cells, come from a very human origin. The cells used by Dr. Fessler began as an unused embryo from an in vitro fertilization. It was donated 12 years ago to Geron Corporation, a biopharmaceutical company that has since cultured a massive supply of frozen cells. Geron scientists then grew them into a population of cells known as GRNOPC1.

    GRNOPC1 produces myelin, which speeds up communication between nerves. Fessler will inject GRNOPC1 into the spinal injury site. There, new myelin will hopefully grow to reinsulate the nerves and restore communication between the brain and the lower body.

    Only people who have lost all movement below the chest are eligible for the study, and they have to receive the treatment within 7 to 14 days of being injured. In animal studies, rats regained the use of their hind legs after scientists injected them with GRNOPC1.

    “You really want it to be successful,” Fessler says. “At the same time, we want to make sure we don’t hurt anybody in the process.”

    Not everyone is confident the trial will be safe. John Kessler, chair of the neurology department at Northwestern, says he would advise patients to consider the risks and benefits before joining the study.

    “Dr. Fessler is probably the person in the world most equipped to do this,” says Kessler, who is not involved in the trial but who also studies stem cells and spinal cord injuries. “If anybody could do it safely, he can. But we have to be concerned about tumor formation. We have to worry about creating additional damage in the spinal cord.”

    Kessler says another concern is whether there is sufficient basis for thinking the treatment would benefit patients with severe spinal cord injuries.
    The first person to enroll in the experiment was treated at another trial site in Atlanta in early October. Despite the risks, Kessler says many more patients will want to participate.

    “These are people who are devastated, and you’re trying to offer them some hope,” Kessler says. “I can tell you there are patients who will just say, ‘I don’t care what the risk is. I want to be able to have this work.’”

    The trial is controversial because the treatment required the destruction of an embryo. Fessler says the potential benefits raise an important ethical question.

    “I understand that many people say use of an embryo is murder and shouldn’t be done,” Fessler says. “But is it more ethical to throw a piece of tissue away and deny hope and treatment to maybe thousands of patients from the knowledge you would gain?”

    Although he has doubts about Geron’s treatment, Kessler says, if successful, the trial could change the future of medicine.

    “The very best institutions in this country are the centers that develop new therapies, that don’t just give a medicine that somebody else developed,” Kessler says. “We’d be developing a brand new treatment, something that no one has ever done before. We’d be changing the state of the art of medicine.”


    blog comments powered by Disqus
    Please read our Comment Policy.