DISEASED and broken bones can be repaired using grafts made from a patient's skin cells, scientists have shown.

Researchers in the US reprogrammed skin to become stem cells that were coaxed to form early stage bone precursors.

The immature bone cells were then "seeded" on to a three-dimensional scaffold and stimulated to grow with nutrients.

Over a period of 12 weeks, grafts placed under the skin of mice matured into fully- formed bone tissue with the beginnings of a blood supply.

Crucially, there was no sign of the treatment generating tumours.

"Following on from these findings, we will be able to create tailored bone grafts, on demand, for patients without any immune rejection issues," said Susan Solomon, chief executive of the New York Stem Cell Foundation (NYSCF) whose scientists carried out the work.

The research is reported in the journal Proceedings of the National Academy of Sciences.

The scientists, led by Dr Darja Marolt, created induced pluripotent stem (iPS) cells from human skin cells.

The cells were tweaked to make them revert to an embryonic-like state. IPS cells have similar properties to embryonic stem cells, including the ability to diversify into any cell type in the body.

Previous research has shown bone can be made from other cell sources. But grafts made from bone marrow lack an underlying blood vessel network and nerve compartments, and those from embryonic stem cells can trigger an immune reaction.

"Bone is more than a hard mineral deposit, it is an active organ that constantly remodels," said Dr Marolt.

Further work is needed before skin cell-derived bone grafts can be given to patients, the scientists pointed out.