Canadian and Italian scientists say they have identified "a master control" gene for turning on blood stem cells, which could lead to a greatly expanded supply of these precious cells for medical treatments.
The discovery, published Thursday in the journal Cell: Stem Cell, follows another major development in 2011, when the Canadian researchers first isolated a human blood cell in its purest form a single stem cell capable of regenerating the entire blood system.
These advances are critical for people who suffer from blood disorders such as leukemia, a form of cancer. Doctors currently treat leukemia by using chemotherapy to destroy the cancerous cells in the bone marrow, where blood cells are produced, in the process also killing off normal blood cells. The blood system is then replaced with healthy cells from a bone-marrow donor.
Worldwide, about 40,000 people a year receive bone-marrow transplants. But an additional 120,000 patients fail to find a suitable match. Many die on waiting lists.
While blood stem cells taken from an umbilical cord have recently offered an alternative transplant source, they cannot be grown in large enough quantities to treat an adult. And even with last year's announcement that Canadians had isolated the prized stem cells that endlessly replenish human blood, they still did not know how to control them.
"Stem cells are actually dormant in the cord blood or in your bone marrow. They lie dormant for long periods of time," explained John Dick, a senior scientist at the University Health Network's McEwen Centre for Regenerative Medicine and the Ontario Cancer Institute in Toronto.
But the discovery of a master control gene could mean that scientists will be able to finally harness the power of stem cells. "Now we have peered into those cells and identified one of these master regulator switches which actually governs the dormancy," Dick said. "By altering the master regulators, you could greatly expand the number of stem cells which could then be used to transplant into an adult."
The researchers still have to identify other genes that regulate blood stem cells. But Dick believes that goal is within their grasp.