Are marrow stromal stem cells systemically transplantable?
The precedent of hematopoietic transplantation has led many to a simplistic view of stromal stem cells and their dependent tissues. The notion that stromal stem cells can be transplanted using the same principles and procedures used for HSCs is clearly an oversimplification. The widely known key principle of bone marrow transplantation (BMT), the seed and soil paradigm, postulates that upon ablation of a recipient marrow, progenitors infused via the circulation (the seed) can home into the nonablated marrow stroma (the soil) and can regenerate a hematopoietic tissue. The principle relies on a few established biological properties of HSC and the dependent hematopoietic lineages that do not apply to stromal progenitors and the dependent connective tissues. Furthermore, the principle of HSC transplantation depends on the remarkable radio- and chemoresistance of marrow stromal cells, traits that facilitate the replacement of hematopoietic cells in a minimally disturbed cellular environment
