New insulin-secreting cells for diabetics
Scientists have found a way to turn the skin cells of diabetics into insulin-secreting cells.
Harvard-based researcher Douglas Melton and colleagues, writing in PNAS, describe how, using genetic techniques, they were able to re-programme skin fibroblast cells collected from two patients with type 1 diabetes into insulin-producing pancreatic.
First the team used several modified viruses to deliver to the cells three genes called OCT4, SOX2 and KLF4, which are known to 'de-programme' specialised cells and turn them into a more primitive cell type known as an iPS cell, short for 'induced pluripotent stem cell'. The resulting iPS cells are very similar in behaviour to embryonic stem cells in that they can, scientists think, be persuaded to turn into almost any type of cell found in the body.
Next the team grew the iPS cells in culture, adding a cocktail of other growth factors to encourage the cells first to re-specialise into endoderm - one of the early tissues in the developing embryo and which gives rise to the lungs, intestines, liver and pancreas.
Next, with the addition of further growth factors, the team were able to trigger the cells to turn into insulin-secreting beta cells of the type normally found in the pancreas. Owing to the genetic modifications that had to be applied to the cells to make these manipulations feasible it would be unsafe to inject these cells back into diabetics, but what they do offer is an opportunity for scientists to study how the cells of diabetic patients interact with the immune system, which will provide clues as to the pathological process that underlies type 1 diabetes and which is a consequence of immune destruction of these cells in the pancreas.
At the same time the cells can also be used to explore new ways to block immune attacks of this type or to tolerise the immune system to these sorts of cells so that future attacks could be avoided. Hearteningly, newer techniques that are now being developed will also render it unnecessary to permanently genetically modify cells to make them re-programmable in the way that Melton and his team have done. This means that the other finding of this paper - the production of new insulin-producing pancreatic cells - could offer a way to produce cells for diabetic patients derived from their own genetic stock and without the need to undergo risky tissue-transplants.