Stem Cell Transplantation for the Treatment of MS
The use of stem cells for the treatment of MS is an up-and-coming area of interest. Preliminary research is promising, however, much more study is needed to determine the safety, efficacy, and best practices involved with stem cell therapy for relapsing-remitting and progressive MS.
What are stem cells?
Stem cells are defined as cells that are self-dividing (have the ability to self-replicate), and are able to develop into different kinds of specialized cells. Stem cells are also capable of creating functional tissue once they differentiate, or develop, into specialized cells. Stem cells are commonly associated with developing embryos, as a small number of embryonic stem cells are responsible for developing into the rest of the human body. However, stem cells are also found in adults and are utilized throughout our lives to repair damage or replace other cells when needed. Stem cells can be found in bone marrow, umbilical cord blood, and adult fat or muscle tissue, among other locations. Different types of stem cells include the following:
- Hematopoietic stem cells (HSCs) - adult stem cells that are found in the blood and bone marrow
- Neural stem cells (NSCs) - Stem cells that are able to repair myelin in the brain (which insulates nerve cells)
- Human embryonic stem cells (hESCs) - Found in embryos and can develop into any kind of specialized cell
- Mesenchymal stem cells (MSCs) - Adult stem cells found in the skin, fat tissue, and bone marrow. These cells are thought to have the ability to aid in the functioning of other stem cells and potentially impact the immune system
- Induced pluripotent stem cells (iPSCs) - Stem cells that have been engineered from adult somatic (body) cells to be able to produce many different kinds of cells
Once stem cells are obtained and manipulated in a lab, they may then be induced or influenced to develop into specific cell types. If this process is successful, these cells may grow into muscle cells, liver cells, neural cells, skin cells, eye cells, blood cells, and more.1,2
How might stem cells be used therapeutically for MS?
There are several theories on the potential mechanisms behind how stem cells could be beneficial for the treatment of MS. One potential option is in utilizing stem cells to reboot the body’s immune system. In this approach, the body’s immune system is destroyed or significantly reduced using medications like chemotherapy. Once the body’s immune cells are depleted, hematopoietic stem cells (which can be harvested from the same individual in advance) are reinfused back into the body where they will initiate the development of a new immune system. Potentially, this new immune system will not attack itself and will behave differently than it did previously. If successful, this may help reduce inflammation that could lead to MS development and progression.1-4
In results presented at the European Society for Bone and Marrow Transplantation in 2018, one study utilizing immune system-rebooting stem cell therapy showed significant promise in the treatment of relapsing-remittent MS. Only 6% of the individuals who had undergone this type of stem cell therapy had relapsed within three years, as compared to 60% in the control (non-stem cell therapy-receiving) group.3,4 More study is needed to determine the safety and efficacy of this type of therapy, as well as to better understand the mechanisms behind its potential success.
Mesenchymal stem cells
Another stem cell therapy option utilizes mesenchymal stem cells (MSCs). MSCs are found in adult fat and muscle tissue, as well as in bone marrow and umbilical cord blood. These cells are more readily available than other stem cell types, and can travel easily within the body, meaning they can travel into and through the central nervous system on their own. These cells are thought to help repair tissue damage, such as the nerve damage that can come along with MS, as well as have immunomodulating (immune system-impacting) effects. They are also able to develop into different cell types, such as bone cells or cartilage cells, and can aid in the functioning of other stem cells.5
MSC’s can be harvested from an individual and can be grown in a lab so that they can be introduced back into the body in larger numbers. MSCs can be taken from the same individual they will eventually be used to treat, or from someone else.5 Several small studies have been published on the safety and potential benefits on the use of MSC’s for the treatment of both relapsing-remittent and progressive MS, however, further study is needed.6,7
Induced pluripotent stem cells
A newer approach that is still currently being developed within stem cell therapy is in utilizing induced pluripotent stem cells (iPSCs) to create a wide variety of cell types. In this approach, body cells are “reprogrammed” in a lab to differentiate, or turn into, pluripotent stem cells. These cells can then go on to turn into a wide variety of different cells and carry out numerous functions within the body. While this approach is promising, it is still in the very early stages of development.1,5
Several other conditions that might potentially benefit from stem cell therapy include, but are not limited to:1
- Traumatic brain injury
- Parkinson’s disease
- Alzheimer’s disease
- Muscular dystrophy
- Rheumatoid arthritis
- Crohn’s disease
- Spinal cord injury
- Heart attack
- Open wounds