Researchers have successfully converted skin and umbilical cord cells into nerve cells, using a method that can be used for biomedical applications.

Producing pluripotent stem cells from skin cells was seen as a big biological development, however, it has not yet managed to produce results efficiently enough to be used for biomedical applications.

Scientists from the Bonn Institute of Reconstructive Neurobiology have expanded upon previous research attempts, and now have the method at the point where it can be used in applications.

This work, led by Julia Ladewig, is an extension of the much-hyped work conducted by Shinya Yamanaka in 2006. This research was met with much excitement, with the promise of being able to reprogram skin cells for the first time with the aid of a few control factors. However, the method has been found to be rather inefficient, with only a small number of the skin cells being converted into the desired nerve cells.

Now, researchers have managed to increase the yields during transformation of cells. Scientists at the LIFE & BRAIN Center at the University of Bonn hypothesised that they could use low-molecular active substances, or small molecules, to optimise the process.

They blocked the SMAD signalling pathway and inhibiting glycogen synthase kinase 3 beta (GSK3ß) and in doing so, increased the transformational efficiency by several times. This meant that they were able to even simplify the means of extraction.

Reducing the number of transcription factors to two, and using three active substances, the Bonn researchers were able to convert a majority of the skin cells into neurons. In the end, their cell cultures contained up to more than 80 per cent human neurons.

Julia Ladewig said: "We can obtain up to more than 200,000 nerve cells converted in this way from 100,000 skin cells.

"We were able to demonstrate how the genes typical for skin fibroblast were gradually down-regulated and nerve-cell-specific genes were activated during the cell transformation. In addition, the nerve cells thus obtained were functionally active, which also makes them interesting as a source for cell replacement."