For the first time, scientists have been able to change one mature type of cell directly into another type of cell, bypassing the potentially cancerous pluripotent stage. Mickie Bhatia lead a team of researchers from McMaster University in transforming human skin cells into blood cells.
Every cell in our bodies contains the same genome as every other cell. However, not all those genes are turned on in all cell types. Specific combinations of gene activation, as well as environmental factors such as nutrients and hormones, determine what kinds of cells will develop. The hard part is figuring out exactly which combinations will create the desired effect. After much trial and error, the researchers discovered that turning on the gene OCT4 was sufficient to reprogram skin cells into becoming blood cells. In addition, playing around with specific growth factors allowed them to manufacture different types of blood cells. For example, leaving out erythropoietin caused the skin cells to change into neutrophils and macrophages (white bloods cells)
In the past, human skin cells have been converted to other types of tissues through a two-step process. First, the skin cells are converted into pluripotent stem cells. Next, these pluripotent cells are programmed to change into any kind of cell, including blood cells. One major drawback of this method is that the pluripotent cells often become cancerous. This new process bypasses the pluripotent stage, and hopefully the ability to form tumors.
The scientists plan to start clinical trials as early as 2012. If those tests are successful, this cell conversion method will be enormously beneficial. Anyone needing blood products, whether due to injury, surgery or cancer treatment will be able to rely on their own skin cells to provide those products. Besides obviating the need to rely on donors, there would be zero risk of rejection.