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British researchers have made significant progress in using stem cells for treating hereditary diseases in the future.

Induced pluripotent stem cells (iPS cells) (SEE THE WACKY SCIENTIST) were used, taken from the skin cells of patients with a metabolism disorder. They changed these cells into cells like those in the liver and then introduced the human cells "cured" in this way into mice with the metabolic disorder.

The hereditary metabolic disease concerned is called Alpha-1-antitrypsin Deficiency, which occurs as the result of the mutation of a single gene (monogenic disorder).Both copies of the relevant genes in the patient need to be changed for the disease to show symptoms. According to the authors, the disease affects one in 2 000 people of northern European origin and can lead to cirrhosis of the liver, which in turn could necessitate a liver transplant.

Alpha 1-antitrypsin is a protease inhibitor belonging to the serpin superfamily. It inhibits a wide variety of proteases and protects tissues from enzymes of inflammatory cells, especially neutrophil elastase. In its absence, neutrophil elastase is free to break down elastin, which contributes to the elasticity of the lungs, resulting in respiratory complications such as emphysema and cirrhosis in adults or children.

Skin cells were taken from three patients with metabolic disease. Stem cells like these are seen as an ethically unproblematic alternative to embryonic stem cells, as they are not drawn from embryos. In the future they are set to be used in cell therapy for a variety of diseases.

As no tumour cells formed in the mice as a result of the intervention - by contrast with similar trials - the study authors believe the possibility exists of making progress using this method in treating monogenic diseases. The human cells apparently integrated into the liver tissue of the mice, taking over their function there. However, the altered iPS cells received mutations in their genetic makeup.