New technique to identify rare stem cells

Stem-cell-based therapies could soon become a lot easier to develop as researchers have found a way to identify a type of immature stem cells within the bone marrow that can help in tissue repair.

These cells known as mesenchymal stem cells (MSCs) can differentiate into cells that produce bone, cartilage, fat, or muscle.

The team of researchers has identified three physical characteristics of MSCs that can distinguish them from other immature cells found in the bone marrow.

"You can now find the needles in the haystack and use them for human therapy," senior study author Krystyn Van Vliet, an associate professor at Massachusetts Institute of Technology in the US.

Based on this information, they plan to create devices that could rapidly isolate MSCs, making it easier to generate enough stem cells to treat patients.

Until now, there has been no good way to separate MSCs from bone marrow cells.

After measuring several other physical traits, the researchers found two that could be combined with size to completely distinguish MSCs from other stem cells: stiffness of the cell, and the degree of fluctuation in the cell's nuclear membrane.

"You do not need more than these three, but you also cannot use fewer than these three," Van Vliet added.

"We now have a triplet of characteristics that identifies populations of cells that are going to be multipotent versus populations of cells that are only going to be able to become bone or cartilage cells."

The researchers tested the regenerative abilities of the isolated MSCs in mice. They found that these cells could help repair both muscle and bone injuries, while cells identified as osteogenic stromal cells were able to repair bone but not muscle.

The study appeared in the journal Proceedings of the National Academy of Sciences.