Official reports have revealed that scientists from the Duke University Medical Center have managed to hit upon a new growth factor which effectively stimulates the expansion and regeneration of hematopoietic, commonly known as blood-forming, stem cells in culture and in laboratory animals.

The discovery, which is all set to appear in the journal Nature Medicine on Sunday, might just aid researchers overcome one of the most difficult and frustrating hurdles to cellular therapy - the fact that the number of stem cells is always very low and these are unusually resistant to expansion.

Researchers have shared the belief that the blood collected from the umbilical cord could serve as a definite and universal source of stem cells for all the patients who require steam cell transplant, but the number of stem cells found in the cord blood are always very limited. There is, therefore, a clinical requirement to come up with a method which can expand cord blood stem cells.

"Unfortunately, there are no soluble growth factors identified to date that have been proven to expand human stem cells for therapeutic purposes", said lead author John Chute.

Researchers have, however, in the new study managed to discover that adding pleiotrophin, which is a naturally occurring growth factor, stimulated an expansion of as much as ten times of stem cells taken from the bone marrow of a mouse.