Bone marrow transplant

Can you imagine a world where every man, woman or child who needed a bone marrow transplant could receive one on demand?

Bone marrow transplantation is a true success story in the field of regenerative medicine. In this procedure, healthy blood stem cells, or hematopoietic stem cells (HSCs), are transferred to a patient with a diseased or damaged blood system, thereby replenishing a lifetime’s supply of healthy blood and immune cells.

These bone marrow transplants have saved the lives of many patients with cancers such as leukemia and various genetic diseases like sickle cell anemia. Scientists believe that when combined with powerful techniques like gene therapy, blood stem cell transplantation will enable unprecedented numbers of new treatments and cures to be developed for an even larger and more complex variety of diseases.

So, what’s the catch? Unfortunately, there are two major hurdles preventing the full benefits of HSC transplantation from being realized. First, the procedures necessary to prepare a patient’s body to receive HSCs carry their own medical risks, limiting their availability to the sickest of patients whose lives are already fragile. Finding gentler methods for this conditioning process is a key area of research. Second, for many people, it is simply not possible to obtain sufficient numbers of healthy blood stem cells for transplant, either from their own bodies or from an immune-compatible donor.

Enter human pluripotent stem cells, which due to their immortal nature and ability to differentiate or change into virtually any cell type in the human body, could provide a renewable source of any cell type contemplated for therapy, including stem cells of the blood. Even more exciting, it’s now possible to create customized pluripotent stem cells from the skin of any individual, thus opening the door to perfectly immune-matched sources of tissue. Scientists have made great strides towards deriving various HSC-like cells, but the holy grail of achieving the correct type of HSC remains elusive.

Why is this the case? What is the true nature of this “HSC Bottleneck”, and what can we do to overcome it? To answer these questions, the stem cell agency (CIRM) organized a mini-symposium last August for a focused discussion with several thought leaders from California and beyond. Not only were specific technical and scientific knowledge gaps identified, but there was also a lively dialogue about what funding agencies can do to accelerate advances in this area of research.

To share what we learned, we recently posted a report on the nature of the HSC bottleneck, and the recent progress that has been made towards overcoming it. Filling this knowledge gap is a challenge for our generation, but one we are confident will be met.

Kelly Shepard, CIRM Science Officer