The hematopoietic, or blood-producing, system resides in the bone marrow
of adult mammals. This system regulates the production of billions of new blood cells
per day in healthy adult humans. Even slight perturbations of this production can lead
to severe pathological conditions. One of the first applications of cellular regenerative
medicine in clinical practice was the transplantation of bone marrow cells to generate a
new, healthy blood production system in compromised patients. The success of bone
marrow transplantation is dependent upon the potency of stem cell and progenitor
populations within the adult mammalian bone marrow. The utility of hematopoietic
stem cell (HSC) transplant has been extended to the treatment of a broad range of
hematological diseases and disorders, as well as in the regeneration of the bloodproducing
tissue following radiation or chemotherapy. There is a strong push towards
the development of vast numbers of mature blood cells in vitro. An in vitro system
resulting in the consistent, large-scale production of patient-specific mature
erythrocytes from HSCs or erythroid progenitors could alleviate the pressure felt by
blood donation agencies. The cells that support blood cell production in the bone
marrow and other organs, known collectively as the hematopoietic niche, are critical in
blood cell lineage regeneration. The development of novel regenerative therapies to
treat myelodysplastic syndromes, anemia, leukemia and other blood diseases deserves
attention. Stem, progenitor and supportive cells within the hematopoietic tissues are
essential elements of regenerative medicine. The utility, limitation and promise of these
populations in regenerative medicine are described here.
Keywords: Bioengineering, Blood, Bone marrow, Embryo, Hematopoiesis,
Niches, Regenerative Medicine, Stem cells, Transplantation.
