Placental stem cells may soon multiply the number of children who can be cured of blood disorders thanks to a research team at Children’s Hospital & Research Center Oakland.
In the 07/09 issue of Experimental Biology and Medicine, Children’s researchers demonstrate that stem cells in human placentas can become blood-manufacturing cells and that they can be harvested. The team was led by principal investigator Frans Kuypers, PhD, senior scientist and Vladimir Serikov, MD, PhD, assistant staff scientist.
“Yes the stem cells are there; yes they are viable; and yes, we can get them out,” declared Dr. Kuypers.
These Stem Cells Save the Lives of Kids With Blood Disorders
Stem cells harvested from umbilical cord blood have already cured hundreds of children with bone marrow-related disorders, including sickle cell disease, thalassemia and leukemia. But upstream from that cord river is a whole placenta lake, filled with many times more stem cells. Harvesting them would mean many more children could be helped.
The placenta is the organ inside a pregnant woman that supplies her fetus with oxygen and food. It also collects fetal waste and disposes of it through the maternal kidneys. After birth, the placenta is expelled and discarded.
CHORI researchers Vladimir Serikov, MD, PhD & Frans Kuypers, PhD
Implanting placental stem cells in special laboratory mice, the team showed these stem cells not only thrived, they “made human blood in the mouse.”
What’s next is demonstrating that placental stem cells, like those found in cord blood, will do the same in a human.
Children’s a Pioneer of Cord Blood Stem Cell Research
Since 1997, using cord blood stem cells, researchers and clinicians at Children’s Hospital, among the pioneers in this work, have cured more than 100 children with bone marrow-related disorders, including sickle cell disease, thalassemia and leukemia.
This new research could dramatically increase the numbers of children and adults who could be treated and cured with such stem cells.
Stem Cells Don't Know the Difference Between 'Self' & 'Not-Self’
The importance of stem cells is that they are relatively immunologically naïve. Their "naïveté" helps them swiftly and safely take up their new job of making blood cells, including white blood cells, one of the immune system's armies. Instead of attacking host cells, the new white blood cells adopt them, becoming part of their host's new immune system. When successfully transplanted, cord blood stem cells take up residence in a patient’s bone marrow, replacing blood-manufacturing cells damaged or destroyed by disease.
“The more stem cells, the bigger the chance of success,” said Dr. Kuypers. “Some day we will be able to serve more kids and adults with this important resource.”
Genetic Match Needed - But Threshold is Lower
Of course, there still needs to be a genetic match between donor stem cells from cord or placental blood, and the cells of the person receiving them, but the threshold is lower, than for bone marrow cells, for example.
Someone ill with sickle cell disease, who needs their blood-making ability restarted, may need to match a bone marrow donor on six markers. But only four of those markers need to match for a good chance at a successful cord blood transplant. Dr. Kuypers is hopeful the same will be proved true of a placental stem cell transplant.
Gathering Placental Stem Cells on a Large Scale is Best Way to Help Kids
Dr. Kuypers believes that harvesting placental stem cells on a large scale is the best and perhaps the only way to feasibly develop their use.
“We’re looking for partnerships with industry to get placenta-derived stem cells in large quantities into the clinic,” said Dr. Kuypers.
That’s why the team also developed a patent-pending process for freezing placentas that allows them to later be defrosted without damaging the stem cells, allowing harvesting of healthy stem cells when they are needed.
This approach makes it possible to gather, ship and store placentas in a systematic way. For example, the placenta of a baby delivered in Fresno could be frozen there and information about the blood entered in a database accessible across the country. Then the placenta could be shipped to a large-scale storage facility in, for instance, Denver.
Once a transplant team, in say, Seattle, searches the database and finds a match, the frozen placenta could be shipped to them, where the stem cell transplant was to be performed. Then the needed stem cells could be extracted from the placenta on site, using a technique developed by Children’s team.
One day, thanks to research at Children’s Hospital Oakland, unneeded placentas like these, and the potentially life-saving stem cells they contain, may give countless sick children another chance at life.
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