McMaster researchers have revealed that human blood stem cells found at the ends of bones may improve bone marrow transplants.

The discovery could lead to a lowering of the amount of bone marrow needed for a donation while increasing regeneration and lessening rejection in the recipient patients, says principal investigator Mick Bhatia, professor and scientific director of the McMaster Stem Cell and Cancer Research Institute.

In a paper published online by the journal Cell Stem Cell, his team reports that human stem cells residing in the end (trabecular region) of the bones display the highest regenerative ability of the blood and immune system.

“Like the best professional hockey players, our findings indicate blood stem cells are not all equal,” said Bhatia. “We now reveal the reason why — it’s not the players themselves, but the effect the arena has on them that makes them the   highest scorers.”

Bone marrow transplants have been done for more than 50 years and are routine in most hospitals, providing a life saving treatment for cancer and other diseases including leukemia, anemia, and immune disorders.

Bhatia, who also holds a Canada Research Chair in Human Stem Cell Biology, said that cells surrounding the best blood stem cells are critically important, as these “stem cell neighbors” at the end of the bone provide the unique instructions that give these human blood stem cells their superior regenerative abilities.

The research was welcomed by others in the field. David Allan, a clinician-researcher with the Blood and Marrow Transplant Program at the University of Ottawa, said the study shows the importance of the bone marrow and bone structures in terms of regulating the blood system.

“To improve the outcome of leukemia treatments and bone marrow transplants, we will have to consider the effects of treatment on the bone structures and supportive cells in the bone marrow,” said Allan. “Dr. Bhatia’s elegant work provides compelling insight on how important the surroundings are in terms of the health of the blood system.”

The research was funded by the Canadian Institutes of Health Research and Ontario Cancer Research Institute.