Reprogrammed cells offer a potential treatment method
In 2006, Japanese scientists discovered that a cell's development can be "backed up" from mature skin cell to the stem cell stage by transferring into them the genes for four proteins, known as transcription factors.
The scientists were then able to show that these cells, called induced pluripotent stem cells (iPS cells), can be reprogrammed to form completely different cell types. The hope is that these reprogrammed cells can be used in the treatment of different diseases where the patients' own cells are dysfunctional, such as Parkinson's disease or diabetes.
Five questions to Outi Hovatta on the potential of laboratory-produced iPS cells:
What are the advantages of iPS cells?
"They can be produced from cells taken from the patient him or herself. This reduces the risk of rejection by the immune defence system when they are grafted back into the patient. Embryonic stem cells, on the other hand, derive from a fertilised egg in the very early stages of development, and are treated by the body as foreign."
How much progress has been made on reprogramming iPS cells to form other cell types?
"There are well-developed techniques today for reprogramming embryonic stem cells to form different cell types. It's assumed that these techniques will also be usable for iPS cells, but as yet research into these cells has yielded few results."
What remains to be done before iPS cells can be used as a treatment for humans?
"The safety aspects are extremely important. At present there is a real danger that the iPS cells form tumours, and this, of course, must be dealt with first."
You have produced these cells - what are the difficulties the method faces?
"It's very time consuming to add the transcription factors into the cells and then identify the few cells that have been transformed into iPS cells. The cells must then be characterised, and far from all cells meet the criteria for pluripotency, which means being capable of forming many different cell types."
Can all cells become iPS cells?
"Skin cells have been the main choice of cell, as they grow well in cultivation and are easy to take from an adult individual. But white blood cells have also been genetically modified to form iPS cells; in theory, it doesn't matter what kinds of cell are used."
Text: Cecilia Odlind. Published in Medical Science, no. 2/2009.