The idea is to revert a patient's blood cells to the stem cell stage and then chemically nudge them to re-specialise into particular tissue types that can be implanted to heal damaged tissue. A huge advantage over using donated tissue is that the transplant would be "autologous" ?made of the patient's own cells, thus avoiding immune rejection.
"It's autologous, we don't need to worry about rejection of tissue, and immunosuppression," says Glenn Winnier of Pharmafrontiers, a company in Woodland, Texas. It now claims to have refined a way to produce stem cells from whiteblood cells called monocytes and develop them into many different tissue types including, crucially, insulin-producing cells.
Most mainstream stem cell researchers are sceptical, however, because the idea that specialised cells like monocytes can be "de-differentiated" back to more primitive stem cells remains heretical. "Let's see first how they perform functionally," says Stephen Minger of King's College London.
Pharmafrontiers is to present its latest results at the end of this month in Toronto at the International Society for Stem Cell Research meeting. Deriving "stem cells" from monocytes was originally reported in 2003 in Proceedings of the National Academy of Sciences (vol 100, p 2426) by a team at Argonne National Laboratory in Illinois, but Pharmafrontiers bought up and refined the technology.
The company says it can de-differentiate monocytes into "multipotent" stem cells by exposing them to certain nutrients and growth factors. Such stem cells can give rise to many but not all tissue types like "pluripotent" embryonic stem cells (ESCs). Different combinations of growth factors can then turn the stem cells i