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 white blood 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 into a range of cell types.
Moreover, Pharmafrontiers says it is about to submit a patent application on a brew that turns the monocytes into pancreatic islet-like cells that produce insulin in response to high levels of glucose. "We now want to transplant these cultures into a diabetic mouse model," says Winnier, adding their results are being prepared for publication in a peer-reviewed journal.
Alan Colman of ES International, a company developing insulin-producing cells from human ESCs in Singapore, is also sceptical. He says it would take huge amounts of blood to produce enough islet cells for individual patients.
Chris Major of University College London says most stem cell researchers have neglected the idea of de-differentiating adult cells in favour of using embryonic stem cells. However, he warned there could be problems with using adult cells, because they have suffered years of genetic damage. "With embryonic cells, they're fresh, and not corrupted," he says.
Other teams are also experimenting with stem cells from blood. A team led by Bernat Soria of the Institute of Bioengineering at Miguel Hernández University in Alicante, Spain, last year reported reversing a mouse form of diabetes with insulin-producing cells developed from blood cells (Gastroenterology, vol 128, p 1774). And researchers at the University of Kiel in Germany led by Fred Fandrich report producing liver cells.
Author: Andy Coghlan
"This article is posted on this site to give advance access to other authorised media who may wish to quote extracts as part of fair dealing with this copyrighted material. Full attribution is required, and if reporting online a link to www.newscientist.com is also required. This story posted here is the EXACT text used in New Scientist magazine, therefore advance permission is required before any and every reproduction of each article in full. Please contact firstname.lastname@example.org. Please note that all material is copyright of Reed Business Information Limited and we reserve the right to take such action as we consider appropriate to protect such copyright."
THIS ARTICLE APPEARS IN NEW SCIENTIST MAGAZINE ISSUE: 24 JUNE 2006
IF REPORTING ON THIS STORY, PLEASE MENTION NEW SCIENTIST AS THE SOURCE AND, IF REPORTING ONLINE, PLEASE CARRY A HYPERLINK TO: http://www.
UK CONTACT - Claire Bowles, New Scientist Press Office, London:
Tel: 44-0-20-7611-1210 or email email@example.com
US CONTACT - New Scientist Boston office:
Tel: 1-617-386-2190 or email firstname.lastname@example.org