SCIENCE OF STEM CELLS
Stem Cell Sources & Types
What are the sources of adult stem cells?
>> DR. MARC PENN: There are multiple sources of adult stem cells. The most commonly thought of is the bone marrow. We’ve done bone marrow transplants for 50 years. We’re using the stem cells from the bone marrow and transplanting them into the recipient. Another source is adipose tissue or fat tissue recognized more recently in the last 20 years as a very rich source of stem cells. Now, both the bone marrow and the fat contain mesenchymal stem cells and endothelial progenitor cells that are key to inducing tissue repair and healing.
Is one source considered better than the other?
>> DR. PENN: The bone marrow, as we age, becomes fibrotic and fatty. So, we end up with fewer stem cells as we get older. Conversely, our fat maintains its stem cell population, and it has a much richer source of mesenchymal stem cells, which are really the conductor or the regulator of the stem cell repair. So, fat turns out to be a very rich supply that we maintain over our life and has been shown by multiple groups now to be very effective in tissue repair.
Are there other types of stem cells that might be used in therapeutics?
>> DR. PENN: In the last ten years, important scientific discoveries have identified what we call induced pluripotent stem cells, meaning we start with an adult stem cell, we take it back to a near embryonic state, and then can differentiate it into multiple if not all cells in the body. So, the concept of being able to use non-adult stem cells has become more interesting because of induced pluripotent stem cells and the fact that they minimize the ethical issues around embryonic stem cells, but still a lot of science and a lot of research needs to be done before we truly understand the potential of these cells.