Major Scientific Advance: Blood From Skin Without Stem Cells

Opinion   |   David Prentice   |   Nov 8, 2010   |   12:20PM   |   Washington, DC

Scientists at McMaster University in Canada have shown that they can transform human skin cells directly into blood cells, without going through an intermediate stem cell stage. 

This is the first evidence for human cells of what is termed “direct reprogramming”—turning one type of cell directly into another type of cell. 

The scientists repeated the experiments, published online in Nature on Sunday, several times using human skin cells from young and old volunteers, to show that the process works no matter the age of the person.

Senior author Mick Bhatia noted:

“We have shown this works using human skin. We know how it works and believe we can even improve on the process.  We’ll now go on to work on developing other types of human cell types from skin, as we already have encouraging evidence.”

Direct reprogramming avoids the practical problems seen with pluripotent stem cells such as iPS cells or embryonic stem cells, both of which are difficult to control and tend to form tumors.  In the report by the Canadian scientists, the reprogrammed cells gene expression never resembled that of embryonic stem cells, and the cells produced didn’t cause tumors in mice. 

The direct reprogramming process also avoids the ethical problems inherent in embryonic stem cell research, which relies on the destruction of young human embryos to derive stem cells.