This is the second part of my blog related to the International Conference on Cell-based Therapies for MS that was held in November 2015. Today I will discuss mesenchymal stem cells.
Mesenchyme refers to a type of cell that makes up much of our blood and lymphatic system as well as connective tissue. Connective tissue forms structures that hold our body together such as bone, cartilage and tissues that surround cells in our organs. Mesenchymal stem cells are capable of reproducing themselves and are able to produce a number of different tissues in the body.
Mesenchymal stem cell research is still in the early stages and there is a lot to be learned about them. For example:
- What is the best source of the stem cells? Should we be getting them from bone marrow, blood or other tissues?
- How should these cells be processed? Should they be used fresh, cultured or frozen? Cultured stem cells can be manipulated to enhance some of the chemical signals that they produce. What signals should be enhanced to make the most effective cell therapy?
- What is the fate of the stem cell? Where do these cells end up in the body and how long do they remain?
Despite many unanswered questions, study of mesenchymal stem cells in MS is moving forward. The MS Center at Swedish participated in a study of mesenchymal stem cells derived from placenta. This phase I study was recently published (Multiple Sclerosis and Related Disorders 2014;3:696–704).
A group from Oxford, UK, recently completed a study of 10 patients with optic neuritis treated with bone marrow mesenchymal stem cells. After a single infusion of cells there was a mild improvement in vision that was sustained for six months.
Other studies of mesenchymal stem cells are underway, including a study of 24 patients with bone marrow mesenchymal cells at the Mellon MS Center in Cleveland. A group from the University of Bristol, UK, is studying bone marrow cells in patients with progressive forms of MS. A large study of approximately 200 patients is about halfway enrolled in Genoa, Italy.
These studies are all early-phase studies, mostly Phase I. These types of studies will help address questions of safety and also help select a dose to carry forward to future studies of these cells. It will take time to understand the best sources for mesenchymal stem cells, how to process these cells for optimal benefit, which patients might benefit most, what the effects of the cells might be and how often treatment should be given.
Future studies will have to address these questions before mesenchymal stem cells become widely available. However, the preliminary studies look promising and it is encouraging that so much work is currently being done.