Adult stem cells flourish in the lab

All stem cells–regardless of their source—share the remarkable capability to replenish themselves by undergoing self-renewal. Yet, so far, efforts to grow scarce hematopoietic (or blood-forming) stem cells in sufficient numbers for use in therapy have been met with limited success.

In their latest study, Stowers Investigator Linheng Li, PhD, and his team identified three distinct molecular mechanisms that operatively drive cell renewal in hematopoietic stem cells. Applying their insight to stem cells isolated from mouse bone marrow, the researchers successfully expanded hematopoietic stem cells a hundredfold in the lab.

The transplantation of human hematopoietic stem cells isolated from bone marrow is used in the treatment of anemia, immune deficiencies, and other diseases, including cancer. However, since bone marrow transplants require a suitable donor-recipient tissue match, close to one in three patients who could benefit from stem cell transplant—and as many as ninety- five percent of nonwhite patients—never find a suitable match.

Hematopoietic stem cells isolated from umbilical cord blood could be a good alternative source. Readily available and immunologically immature, they allow the donor-recipient match to be less than perfect without the risk of immune rejection by the transplantee. Unfortunately, their therapeutic use is limited since umbilical cord blood contains only about one-tenth of the stem cells found in bone marrow.

“Being able to tap into stem cells’ inherent potential for self-renewal could turn limited sources of hematopoietic stem cells such as umbilical cord blood into a readily available stem source with significant clinical impact,” says Li, while cautioning that his team’s findings have yet to be replicated in human cells.

The study was published in the September 15, 2011, edition of Genes & Development.