The words ‘Stem Cell Treatment’ are often associated with embryonic stem cell use, which can be controversial. Adults, however, also generate stem cells, and several treatments have already been utilizing adult stem cells for decades.
Types of Stem Cell Transplants
Types of Adult Stem Cells
Regardless of where they are obtained in the body, stem cells possess 3 unique qualities that make them stand out from all other cells in the body:
- These cells are undifferentiated, meaning they have yet to develop into a specific cell variant
- They can be used to generate specialized cell types
- Adult stem cells can also be renewed and regenerated over longer periods of time
Unlike embryonic stem cells, adult stem cells do not require the destruction of an embryo and can be obtained through a tissue sample.
Adult stem cells can be used to treat a variety of issues and ailments including macular degeneration, diabetes, burns and arthritis. In addition, stem cells have also been used successfully in cancer treatment and recovery plans. There are essentially two different types of stem cell treatment types related to cancer: Autologous transplant and allogeneic transplantation.
Autologous stem cell treatments refer to treatments that use stem cells harvested from the person receiving the treatment.
Prior to a patient receiving chemo or radiation therapy, stem cells will be removed from either their blood or bone marrow and frozen. The patient is then given a therapy meant to target the cancer cells. In the process, some of the health cells used to generate blood will be damaged or destroyed. At this point, the patient is then administered a dose of their own, previously harvested, undamaged cells, which will then begin repairing the body.
One major benefit to this treatment is that the cells used were created by the patient’s own body, which means there is zero risk of rejection. Additionally, there is no threat of introducing foreign bodies or infections that could have come from a donor.
A major risk for this type of transplant is that cancer cells may also get harvested with the stem cells, and will be reintroduced to the patient when the blood cells are put back into the body. Treatment centers may attempt to ‘purge’ cancer cells from the stem cells, but there isn’t significant evidence to show that this method is successful. Attempts to remove cancer cells may also damage or destroy healthy cells.
Allogeneic transplants utilize stem cells from a donor. If a patient has a donor that is closely related,a sibling, for example, the risk of complications is much lower. Research is currently underway to understand how umbilical cord blood can be used in allogeneic transplants. Cord blood is usually harvested in smaller amounts, but the stem cell density in it is much higher than in adults.
Generally, however, cord blood does not generate enough stem cells to treat a full size adult. Strategies to overcome this obstacle include doing dual-cord blood transplants, where blood from two umbilical cords are used, or allowing the stem cells from one umbilical cord to multiply before they are administered to the patient.
The “graft-vs-cancer” effect is a substantial, though not always guaranteed, benefit of allogeneic transplants: donor cells will often make their own immune cells, which end up being an additional force to fight any cancer remaining after a high dose cancer treatment. Also, a donor for the transplant can often donate more stem cells than could be taken from a patient’s own body.
The drawbacks to this treatment would be this risk of a failed graft. Donor cells may die or be destroyed before establishing themselves in the bone marrow. Conversely, the donated cells that could be helpful in attacking remaining cancer cells may also end up attacking healthy cells in the patient.