Scientists at a US university have successfully converted human skin cells into fully-functional pancreatic cells.

The new cells produced insulin in response to changes in glucose levels, and, when transplanted into mice, the cells protected the animals from developing diabetes in a mouse model of the disease.

The study, conducted by scientists at the Gladstone Institutes and the University of California, San Francisco (UCSF), also presents  significant advancements in cellular reprogramming technology, which will allow scientists to efficiently scale up pancreatic cell production and manufacture trillions of the target cells in a step-wise, controlled manner, a Gladstone Institutes statement said.

"Our results demonstrate for the first time that human adult skin cells can be used to efficiently and rapidly generate functional pancreatic cells that behave similar to human beta cells," said Matthias Hebrok, director of the Diabetes Centre at UCSF and a co-author of the study.

"This finding opens up the opportunity for the analysis of patient-specific pancreatic beta cell properties and the optimisation of cell therapy approaches," Hebrok added.

In the study, the scientists first used pharmaceutical and genetic molecules to reprogramme skin cells into endoderm progenitor cells early developmental cells that have already been designated to mature into one of a number of different types of organs.

With this method, the cells don't have to be taken all the way back to pluripotent stem cell state, meaning the scientists can turn them into pancreatic cells faster. The researchers have used a similar procedure previously to create heart, brain, and liver cells.

After another four molecules were added, the endoderm cells divided rapidly, allowing more than a trillion-fold expansion. Critically, the cells did not display any evidence of tumour formation, and they maintained their identity as early organ-specific cells.

The scientists then progressed these endoderm cells two more steps, first into pancreatic precursor cells, and then into fully-functional pancreatic beta cells.

Most importantly, these cells protected mice from developing diabetes in a model of disease, having the critical ability to produce insulin in response to changes in glucose levels.

"This new cellular reprogramming and expansion paradigm is more sustainable and scalable than previous methods. Using this approach, cell production can be massively increased while maintaining quality control at multiple steps," said Sheng Ding, a senior investigator in the Roddenberry Stem Cell Centre at Gladstone and co-author of the study.

The study findings were published in the latest issue of the journal Nature Communications.