The first formal clinical trial of a prenatal stem cell therapy will launch in Europe next January, researchers announced on Monday.
The trial will involve fetuses diagnosed with brittle bone disease, a genetic disorder that leaves bones so fragile they fracture constantly, even before the baby is born. The condition, which is caused by a genetic problem with collagen production, is incredibly painful. Those with severe forms of the disorder may be confined to a wheelchair.
Surgeons at institutions around Europe will inject mesenchymal stem cells — a type of cell that's already on the path to become bone — into fetuses with brittle bone disease, also known as osteogenesis imperfecta. The technique is currently in experimental use for adult humans with the disorder, as well as other tissue and immune diseases.
The fetal stem cells used in the clinical trials will be donated by women who have already chosen to have an abortion.
"A vast majority of women do donate their tissue" when asked, Cecilia Götherström, a senior researcher at the Karolinska Institute and the primary investigator on the clinical trials, told BuzzFeed News. "When they have to make such a difficult decision, it feels quite good to help out research."
Other researchers say this line of study highlights the importance of scientists having continued access to fetal stem cells.
"This is just another example where fetal tissue could be really useful and important, not only for biomedical research, but specific patients," Paul Knoepfler, a stem cell researcher at UC Davis, told BuzzFeed News.
The trial, led by the Karolinska Institute in Sweden, will enroll 30 pregnant women.
Half of the fetuses will be injected with fetal stem cells in the womb, and then again every six months after birth. The other half will only get the injections after they are born.
The team at Karolinska has already done the procedure on two fetuses who have since been born. The two children have continued to receive periodic "boosters" of stem cells, which have reduced the number of fractures compared with children with brittle bone disease and no stem cell injections.
"It's important to remember that this is not a cure," the primary investigator on the clinical trials, Cecilia Götherström of the Karolinska Institute, told BuzzFeed News. Instead, researchers are hoping to turn severe brittle bone into a mild illness, improving quality of life.
Brittle bone disease is a good candidate for stem cell therapy, according to Francesca Mariani, an assistant professor at the Eli and Edythe Broad CIRM Center for Regenerative Medicine and Stem Cell Research at the University of Southern California. People with the disorder produce faulty collagen proteins, which are essential for building bone.
"By introducing stem cells that have the normal collagen gene, then they can release this protein and facilitate the strength of the bones," Mariani told BuzzFeed News.
Bone is constantly broken down and rebuilt throughout a person's life, but the injected stem cells don't remain in the body. That's why the clinical trial includes new injections of stem cells every six months for two years.
Although the two children who were treated in-utero have had positive outcomes, there are still risks to this procedure.
The stem cells are injected into the bloodstream of the fetus, and the injection itself carries a miscarriage rate of 1 to 2%. Because the cells can go almost anywhere in the body, it's possible that they could get their signals mixed up and differentiate into the wrong kind of tissue, creating a tumor. There's also some risk that the fetus's body will reject the foreign cells.
"Stem cells are, in a sense, a living drug product," Knoepfler told BuzzFeed News. "We don't necessarily know what those cells will do down the road. That has to be balanced against the potential benefits."
Other researchers at UC Davis have used similar stem cell treatments on lamb fetuses that have been bred to model humans with spina bifida, a spinal birth defect. The success of those animal trials suggests that prenatal stem cell research could be expanded to other genetic disorders.
This first clinical trial is so important because scientists don't know much about how fetuses will respond to stem cell therapy.
"The fetal environment is really different, and we don't know much about it," said Aijun Wang, co-director of the Surgical Bioengineering Laboratory at UC Davis and one of the scientists working on spina bifida. "In the fetal environment, the immune system is underdeveloped, so the transplant may be able to stay in the fetus longer."