Multipotent stem cell research has come into the mainstream, as regenerative medicine exits its infancy and begins to take hold in major healthcare markets worldwide. The possibilities inherent in multipotent stem cells – those capable of turning into a wide variety of different bodily cells – make it one of the most exciting developments today.
Understanding Multipotent Stem Cell Benefits and Applications
In this article:
- Differentiating a Multipotent Stem Cell From Other Stem Cells
- What Exactly Are Stem Cells?
- What Are Multipotent Stem Cells?
- Where Do Multipotent Stem Cells Come From?
- What Is Stem Cell Plasticity?
- Are There Risks Associated with Multipotent Stem Cells?
- What Does the Future Hold?
Differentiating a Multipotent Stem Cell From Other Stem Cells
First, you need to understand stem cell definitions. Next, you need to understand where these stem cells come from, what can be done with them, and the role that stem cell plasticity plays. Finally, we will take a look at the risks inherent with multipotent stem cell applications.
What Exactly Are Stem Cells?
Stem cells are a class of cells, undifferentiated in nature, and therefore capable of turning into a wide variety of different tissue types. Unlike regular cells, which can only divide or renew so many times before they wear out or must die off, some stem cell types are capable of nearly infinite reproduction.
Many types of stem cells turn into a specific line of cells. For instance, hematopoietic stem cells (HSCs) can turn into a range of blood cell types. They can turn into platelets, white blood cells, and more. When introduced into the blood, these stem cells can determine which cells the body needs and manufacture them. The stem cells then continue to divide and proliferate until the patient reaches stable levels.
What Are Multipotent Stem Cells?
Stem cells provide different levels of flexibility. Totipotent stem cells can form every type of cell in the body, as well as all of the embryonic tissues. These stem cells are formed with a female egg and male sperm combine to create a fertilized egg, called a zygote.
The next level is pluripotent stem cells. At approximately four days into embryonic development after the creation of a fertilized egg cell, these totipotent cells begin to specialize slightly into pluripotent cells. Pluripotent stem cells can become all of the cells that create the human body, but are not as versatile as the totipotent cells.
Next, pluripotent stem cells specialize slightly into multipotent stem cells. These stem cells can turn into multiple types of cells and tissues, which is what gives them that name. Mesenchymal stem cells (MSCs) are one of the multipotent stem cell types. MSCs have the ability to turn into a wide variety of cells. For example, they can become bone, cartilage, muscle, and more.
Where Do Multipotent Stem Cells Come From?
You can find multipotent stem cells in many parts of the body. They exist in bone marrow, fat tissue, dental pulp, heart tissue, and many other places. These are all adult stem cells, although multipotent stem cells also exist within perinatal tissues, such as umbilical cord blood and tissue and placental blood and tissue. While they cannot turn into every type of cell, multipotent cells are more powerful than blood stem cells, for example, which can only turn into other blood cells.
A stem cell’s origin can substantially impact the types of cells that it has a tendency to become.
What Is Stem Cell Plasticity?
Historically, researchers have classed stem cells depending on where in the body they originated and assumed that they were limited to that lineage or type of tissue. Thus hematopoietic stem cells – found in the blood – were thought to produce various types of blood cells. Similarly, adipose-derived stem cells – found in fat – were thought to produce mostly cells and other cells of the musculoskeletal system.
However, this no longer appears true. Current research suggests that stem cells are actually much more flexible than this, and can turn into a wide variety of tissue types other than the tissue from which they were harvested. This is called stem cell plasticity. In taking on new identities, stem cells offer physicians and researchers the ability to heal patients that have suffered damage to a specific tissue. What the physicians must do is replace the damaged tissue with another kind of tissue that has not suffered harm.
This could prove useful in various situations. For instance, if a patient has leukemia, they might need chemotherapy to kill cancer in the blood, which would also kill functioning cells. Without replacement, the patient would not have enough blood cells to survive. With an injection of hematopoietic stem cells, physicians can replace those lost blood cells. Hematopoietic stem cell transplantation (HSCT) is a common medical procedure in which this is done.
However, in some cases, the patient’s own stem cells cannot be used. In this case, a an allogeneic transplant may be pursued. An allogeneic transplant is the use of stem cells from someone else (a donor).
Stem cell plasticity may also prove beneficial to a patient who has suffered a major injury to one of their organs and is unable to replace enough of the tissue to survive. These are a few examples of the powers of adult stem cells.
Are There Risks Associated with Multipotent Stem Cells?
As with all stem cell therapy, dangers may arise from using multipotent stem cells for therapeutic applications. Their ability to turn into multiple types of cells makes them very valuable. However, it does not make them immune to the dangers intrinsic to cell-based therapies.
One of the most severe of these risks is a condition called graft-versus-host disease (GvHD). GvHD happens when a patient is not able to use his own autologous (self-derived) stem cells, and thus, obtains cells from a donor. Even in cases where a genetic match between a patient and donor is established, the donor cells may still ignite a reaction from the patient’s body. Essentially, the patient’s cells see the donors cells as “invaders,” and thus attack them as they would any toxin or disease.
In these situations, the patient’s immune system may reject the transplant. Instead of incorporating the cells and allowing them to proliferate, it will instead shut them down.
Ironically, some stem cell types are also predisposed to forming tumors inside the patient, such as embryonic stem cells (ESCs) and induced pluripotent stem cells (iPS cells). Because these cells can proliferate repeatedly and turn into many different types of cells, they hold the potential to become tumors.
What Does the Future Hold?
Overall, the promise of multipotent stem cells is greater than the risk. For this reason, the stem cell industry continues to expand rapidly, with new technologies emerging all the time.
Interested in more information about multipotent stem cells? Understand the basics of stem cells with this video: