'By reprogramming cells to a pluripotent state and making beta cells, we are now one step closer to being able to treat diabetic patients with their own insulin-producing cells', said Dr Dieter Egli, from the New York Stem Cell Foundation, who led the research.
In the latest study, the team replaced the nucleus of a donated human egg with a nucleus from the skin cell of a 32-year-old woman with type I diabetes, in a process called somatic cell nuclear transfer (SCNT). After being exposed to electronic pulses and chemicals, the cell began to divide in a similar way to a fertilised egg, forming a ball of a few hundred cells. From this blastocyst, scientists removed stem cells and transformed them into insulin-producing beta cells.
The approach could someday aid treatment of type 1 diabetes, where the body cannot make enough insulin.
'I think this is going to become reality', Dr Egli said. 'It may be a bit in the future but it is going to happen'.
'This is an important demonstration that SCNT works and can be used to model and perhaps one day treat disease', Professor George Daley from Harvard Medical School, who was not involved in the research, told The Scientist.
In an interview with Nature News, Dr Robert Lanza, co-author on the first stem cell paper, pointed out that if treatment was tailor-made for each patient, an embryo would have to be discarded every time. As well as the ethical objections this would raise, the procedure would be time-consuming, costly and would be limited by the small number of eggs donated.
To make the process more efficient, the embryonic-like stem cells could be transformed into the final product in advance so heart cells or neurons, say, could be picked 'off the shelf' as needed, said Dr Lanza.
But extensive preclinical testing will be needed before the technique can be used therapeutically. The researchers are also working to determine how to prevent the immune systems of diabetic patients from attacking the insulin-producing stem cells.
The next step for the team is to transplant the insulin-producing cells into mice to see whether they grow into functioning human beta cells.