Discoveries could lead to better stem cell treatments

Two recent blood stem cell discoveries could improve the safety and efficacy of stem cell therapies.

In one study, published in the journal Nature Communications, US-based researchers from the Cedars-Sinai Medical Centre, California and University of California, Los Angeles, investigated the poorly understood mechanism that controls bone marrow regeneration.

'We've discovered a mechanism that appears to control how blood vessels regenerate following injury,' said Dr John Chute senior author of the study.

Researchers discovered that a certain protein was secreted in damaged blood vessels in mice, and expression of this protein triggered a pathway which leads to cell death. By administering an antibody that binds with one of the receptors in this pathway or deleting expression of that receptor, they observed reduced cell death and improved blood vessel growth.

When cancer patients receive chemotherapy or radiation it normally causes their blood cell counts to plummet, which can put them at risk of many complications, some of which could be fatal.

'Inhibiting this mechanism causes rapid recovery of the blood vessels and blood cells in bone marrow following chemotherapy or irradiation. In principle, targeting this mechanism could allow patients to recover following chemotherapy in one to two weeks, instead of three or four weeks as currently experienced,' said Dr Chute.

In another study, published in the journal Blood, the researchers from the same team, discovered a certain protein was expressed ten-fold higher in early, pluripotent blood stem cells than in more differentiated ones.

'We show that this protein, syndecan-2, identifies primitive blood stem cells and it regulates stem cell function,' said Dr Chute.

In this study, bone marrow cells from adult mice were extracted and put through a detector that can identify hundreds of different types of cells based on the proteins that live on their surfaces. The researchers found stem cells that express syndecan-2 and transplanted these into mice following irradiation (to mimic chemotherapy) and observed improved numbers of long term blood stem cells.

Authors suggest this protein could be used as a marker of these primitive stem cells to help identify the best stem cells to transfer when carrying out stem cell transplants.