What is Stem Cell Therapy and can it be used to treat LGMD2B?
Stem cell therapy has been mentioned as a therapeutic option for a diverse group of diseases such as cancer, Parkinson, and muscular dystrophy. Stem cell therapy involves introducing stem cells into patients to replace damaged tissues. There are two main kinds of stem cells: embryonic and adult. Embryonic stem cells are only found in developing embryos and these cells can develop into any cell type in the human body. Adult stem cells can come from a variety of sources in the body, but are more limited in the cell types they can become. The most well-known stem cell therapy is a bone marrow transplant which is used to treat certain cancers of the blood. Bone marrow stem cells are adult stem cells that give rise to red blood cells that carry oxygen throughout the body and white blood cells that fight infection.
In patients with a genetic disease like muscular dystrophy, stem cell therapy is a very attractive option because injection with a specific type of “stem cell” that can make muscle and express the missing protein has the potential to repair abnormal muscle function. However, there are numerous obstacles that must be overcome to make this type of therapy possible for muscular dystrophies. These obstacles include the identification of a stem cell type that has the ability to fuse with and become muscle and how to obtain enough cells for treatment. While researchers have found a possible stem cell, called a mesoangioblast, that has the ability to become muscle, obtaining enough of the cells for treatment is still proving difficult.
Just as with organ transplants, the donor “stem cells” must be a “match” for the patient, or the cells will be rejected. There are two ways to obtain a “matched” cell: use cells directly from the patient or find someone who “matches” the patient as closely as possible. Since it can be difficult to find a “matched” donor who is willing to provide a sample, using the patients’ own cells is a very attractive option. However, in the case of muscular dystrophies, the patients’ cells are missing the necessary protein needed to treat the disease, so genetic correction of the patients’ own cells is necessary to make them express the missing protein. This can be accomplished by collecting the specific “stem cells” from a patient, genetically altering the cells in a test tube so that they express the missing protein, and then putting the genetically corrected cells back into the patient. Using this method you are essentially combining stem cell and gene therapy.
Recently scientists used this technique to test stem cell therapy for a type of muscular dystrophy called , Limb-girdle muscular dystrophy type 2D (LGMD2D - caused by the absence of a protein called alpha-sarcoglycan) (http://www.ncbi.nlm.nih.gov/pubmed/22745439). In this study scientists isolated mesoangioblast stem cells from adult patients with LGMD2D. These mesoangioblasts were then genetically corrected in a test tube and put into mice with LGMD2D to see if these genetically corrected “stem cells” could cure the mice of the disease. The researchers showed that the LGMD2D mice were able to express the missing protein, alpha-sarcoglycan, and could run longer on a treadmill than mice that were not treated.
This research shows that there is potential for this type of therapy for muscular dystrophies, including dysferlinopathy (LGMD2B/Miyoshi). It is difficult to estimate how long it will take before this type of therapy will be available. The next steps in getting this technology into the clinic will be extensive studies in mice, as well as clinical trials to demonstrate the safety and effectiveness of this technique to regulatory agencies such as the US FDA. The Jain Foundation is exploring ways to help move this research forward. An important point to note regarding the application of this combined stem cell/gene therapy approach is that each individual needs to be genetically diagnosed by the identification of mutations in the dysferlin gene in order to be eligible for such a treatment. If you are unsure whether or not you have been genetically diagnosed the Jain Foundation can help. Please contact the Jain Foundation’s Director of Patient Relations, Sarah Shira, at or 425-882-1440 or click here for more information.