Stem cell transplantation for treatment of MS

There is great interest in the potential for stem cell transplantation to help repair nerve damage caused by MS. Although several different types of stem cells have been considered to be potentially useful, including embryonic stem cells and neural stem cells, the limited availability of these types of stem cells makes large-scale studies difficult. One type of stem cell called a mesenchymal stem cell (MSC) is more widely available for testing and possesses immunomodulatory, protective, and reparative properties that make it a very attractive candidate for testing in MS.

MSCs are stem cells that come from various sources including bone marrow, umbilical cord blood, or adult fat (adipose) tissue or muscle tissue.  MSCs can differentiate or change into a variety of cell types, including bone cells, cartilage cells, and fat cells. It is believed that MSCs work to repair tissue damage, such as the nerve damage that occurs with MS, by producing cell growth factors and stimulating other cell repair mechanisms. MSCs are also able to readily move from the blood stream to sites of injury in the CNS, making the need for injection directly into the CNS unnecessary.

Transplantation of MSC has been tested in animal studies and shown to be effective in repair of tissue damaged by inflammation and injury and is now being tested in human studies. Several small studies have tested transplantation of autologous MSCs, which are taken directly from an individual and used to treat that individual, with promising results.

In one recently reported study, 25 people with primary-progressive MS (PPMS) who failed to respond to other treatments were observed for 1 year following a single injection of autologous MSCs. The majority of participants had either an improvement or stabilization of disease course, with mean Expanded Disability Status Scale (EDSS) score for the 22 patients who completed the study changing from 6.1 to 6.3 (4 patients showed an improvement in EDSS, 6 had a deterioration, and 12 had no change). Among patients for whom MRI results were available, patients showed no change on MRI scans (n=15) or new T2 or Gd-enhancing lesions (n=6). Treatment was not associated with major adverse effects.

A Phase 1 study, funded by the US Department of Defense and National Institutes of Health, testing MSC transplantation in people with relapsing-remitting MS (RRMS) and secondary-progressive MS (SPMS) is currently underway. This study, conducted by the Cleveland Clinic, will use MRI results (i.e. number of Gd-enhancing brain lesions) to evaluate the effects of autologous MSC transplantation in 24 participants. The primary aim of the study, which is scheduled for completion in 2014, is to test the feasibility, safety, and tolerability of the procedure.

Written by: Jonathan Simmons | Last reviewed: May 2015.
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