Blood `affects stem cell growth`

Scientists claim to have found that mature blood cells could affect the growth of their stem cell "parents".

Updated: Dec 01, 2010, 12:55 PM IST

Washington: In what may pave the way for effective treatment for blood disorders, scientists claim to have found that mature blood cells could affect the growth of their stem cell "parents".

An international team, led by Walter and Eliza Hall Institute, has discovered that blood cell disorders can cause disturbances in the feedback loop, with profound effects on the blood stem cells.

Lead scientist Prof Doug Hilton said the findings have revealed a relationship between the blood cells that was not known to exist until now.

"We know that blood stem cells give rise to all the mature blood cells, but the standard assumption was that external factors control blood cell production and the two populations exist in isolation.

"This study shows that the mature cells actually communicate back to the stem cells, changing their gene expression and influencing their behaviour," he said.

In fact, in their research, the scientists made the discovery while studying the effect of the loss of Myb, a transcription factor that represses platelet production, in animal models.

Team member Dr Carolyn de Graaf said the loss of the Myb gene meant the animals had very high numbers of platelets in their blood, which caused changes in the signaling pathways that control stem cell maintenance.

"The stem cells, rather than being maintained in a `resting state` until needed, were being told to continually cycle and produce mature blood cells. The stem cells were eventually exhausted and blood disorders developed because there were not enough stem cells to produce new red and white blood cells," he said.

The team used new generation genomic technologies to identify gene signatures in the blood stem cells that were caused by the defective signalling, these gene signatures could be used in the future to diagnose and treat disease.

"If we can understand the genes important for stem cell maintenance and blood cell production, then we can start to look at ways of improving transplantation techniques and therapies for blood disorders," Dr de Graaf said.

Prof Hilton said that patients with stem cell failures could also potentially benefit.

"What we would like to do is to determine whether some of these stem cell failures are due to miscommunication between mature blood cells and stem cells with possibility of finding ways to treat the disorders down the track," he said.

The findings have been published in the `Proceedings of the National Academy of Sciences` journal.

PTI