FDA Supports the Development of Mesenchymal Stem Cells as Medical Therapies
Scientists at the US Food and Drug Administration (FDA) are developing techniques to help identify which mesenchymal stem cells (MSCs) are most likely to be reliable therapies for certain diseases. MSCs are stem cells that can differentiate into a variety of cells types, including those that form fat tissue, cartilage, or bones, depending on the conditions of the culture they are grown in. The FDA work is aimed at helping scientists predict whether MSCs have responded to stimuli known to make them differentiate into specific cell types, that is, counting the stem cells that will specifically produce fat, cartilage, or bone.
As a critical part of this work, FDA scientists, from the Center for Biologics Evaluation and Research (CBER) adopted for the first time an existing laboratory technique called limiting dilution assay to monitor how many MSCs from specific populations of these cells will be able to differentiate into fat-producing cells. The technique could also be used to identify which MSCs are likely to differentiate into cartilage and bone-producing cells.
The results of the FDA study suggest that the ability MSCs have to differentiate into fat-producing cells depends in part on which donor provided them and on the number of passages the cells undergo.
MSCs have significant advantages as potential medical treatments for many diseases because they are readily available in bone marrow and adipose tissue (fat), can differentiate into any of a variety of tissues when properly stimulated, and are easily grown in the large numbers needed for use as medical treatments. In addition, MSCs suppress immune system rejection of donated MSCs in those individuals receiving them, increasing the likelihood of treatment success.
However, using MSCs for medical treatments poses two potential problems. First, these stem cells must be passaged repeatedly to ensure there are enough healthy cells available as a treatment for a particular disease. Passaging can reduce the ability of cells to differentiate. Second, since MSCs used to treat patients might come from a variety of donors, they could contain populations of cells that vary in their ability to differentiate, especially after repeated multiplication and passaging. This emphasizes the need to find donor-related factors in MSC variability that affect the clinical usefulness or performance of these cells.
Therefore, the successful adoption of the limiting dilution assay to MSCs in order to enumerate progenitor cells from different donors and passages that will become effective cells is an important step in support of developing reliable MSC therapy. Specifically, it offers scientists a potential tool for identifying the measurable characteristics that can quickly and reliably predict if a particular population of such cells will proliferate (multiply) and differentiate.
H&B
Srhealth
