Four boys with a rare and often fatal brain disease were implanted with stem cells that began fixing damage that impeded their ability to walk, talk and eat, a trial found.
The findings, published today in the journal Science Translational Medicine, are from the first stage of human tests funded by StemCells Inc. (STEM), a Newark, California-based company.
The children have a genetic disorder called Pelizaeus- Merzbacher, in which the brain can’t make myelin, the fatty insulation for nerve cells that helps conduct brain signals. The children all had evidence of myelin growth a year later. The increased abilities shown by three of the boys in the University of California San Francisco study may bode well for other diseases caused by a lack of myelin insulation, including multiple sclerosis and cerebral palsy, the authors wrote.
“Those were severely impaired children,” said Stephen Back, a professor of pediatrics and neurology at Portland’s Oregon Health & Science University, in a telephone interview. “The fact that they showed any neurological improvement is very encouraging.”
Back did work in mice that preceded today’s work in humans, which he wasn’t directly involved in. His study, published simultaneously, showed that the animals with no myelin at all grew some after being implanted with human stem cells.
Pelizaeus-Merzbacher disease causes the degeneration of the nervous system, and there is no cure or standard treatment. People with the illness experience a loss of coordination, thinking and motor abilities. It’s one of several disorders linked to genes that control myelin production.
The incidence of the disease is 1 in 200,000 to 500,000 people, according to today’s study of the boys.
The boys were between the ages of 1 and 6. They were given purified neural stem cells from a fetal brain, which was then grown in culture. The stem cells were inserted into the frontal lobe, using brain imaging as a guide. The boys’ brains were scanned 24 to 48 hours after surgery to assess safety.
The children were on drugs to suppress their immune systems and prevent their bodies from rejecting the stem cells for nine months. Side effects included rashes, diarrhea and fever. One boy had fluid collect under his scalp, which later vanished on its own. A second subject had some bleeding in the brain after the surgery, which was “without clinical consequence,” according to the paper.
One of the boys developed the ability to take steps with assistance and began to speak single words. Another started eating solid food on his own. A third began to walk without the assistance of a walker and began eating on his own.
“They weren’t walking independently, they were being feed with feeding tubes, some had tubes for breathing” before being given the stem cells, Back said.
All of the boys will be monitored for another four years in a separate study. Because myelin can’t be directly studied in the living brain, Back’s work in mice was necessary to show how to measure it on MRIs.
StemCells, which is also investigating spinal cord injuries, is the first and only company to complete U.S. clinical trials using human neural stem cells. The company uses “adult” cells that are pre-programmed to become the organ in which they are found, unlike embryonic cells and induced pluripotent stem cells, which can become any part of the body.
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