How are cord blood stem cells different from other sources of stem cells?
Most of the stem cells in cord blood are blood-forming stem cells, also known as “hematopoietic” stem cells or HSC. The presence of HSC is what enables cord blood transplants to be used as a substitute for bone marrow transplants.
However cord blood transplants have advantages and disadvantages compared to stem cell transplants from adult donors. The main advantage of cord blood is that it does not have to be exactly matched to the patient like transplants from an adult donor. The main disadvantages are that it is hard to collect enough cord blood to transplant an adult, and cord blood stem cells are slow to engraft.
Cord blood also has applications in regenerative medicine. This is due to a combination of additional types of stem cells in cord blood, plus the fact that the cells in cord blood release chemicals that signal the body to heal itself. These chemicals are called cytokines and the cell-to-cell signalling is called the paracrine effect.
Over the past decade infusions of cord blood stem cells have been used around the world as therapy for infants with cerebral palsy and other brain injuries. Published studies have shown that cord blood stem cells benefit young children with neurologic injury, even though the mechanism of action is not yet fully understood. More studies against control groups are in progress.
In the United States, cord blood stem cells have been used in a clinical trial for adults with stroke, and more trials are planned for demyelinating diseases like multiple sclerosis. In China, cord blood stem cells are in a trial for spinal cord injury.
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