New bone grown from monkey's skin cells

Dubbed as a step towards the development of safe stem cell therapies for humans, researchers have successfully grown a new bone using a monkey's own skin cells.

The researchers used induced pluripotent stem cells (iPSC) which are derived from adult skin cells and can be reprogrammed to work as other cells.

"Because monkeys are the closest model species to humans, with similar organ and tissue structure and immunity, testing iPSCs in monkeys should be indicative of the safety and efficacy of the process in humans," said senior author Cynthia Dunbar from the National Heart, Lung, and Blood Institute in the US.

Pluripotent stem cells can be used to make any type of healthy human tissue and therefore have great potential for treatment of disease, say experts.

According to Dunbar, the results would sidestep ethical issues surrounding the use of embryonic stem cells.

For the study, skin cells were taken from rhesus macaques to form stem cells (iPSCs), which were then turned into bone-forming cells.

These "bone" cells were then implanted into the monkeys on ceramic particles that were already in use by reconstructive surgeons attempting to fill in or rebuild bone.

The implants were retrieved at eight, 12 and 16 weeks with bone shown to be forming as early as eight weeks, the authors reported.

Previous work in this field has relied on scientists giving human iPSC products to immuno-deficient mice, she said.

"But because of the species differences, the cells do not behave normally in mice, and the lack of the immune system means that issues of immune rejection or inflammation cannot be studied," said Dunbar.

The team is now working on creating iPSC models for treatment of liver, heart, and bone marrow disorders.

The findings were published in the journal Cell Reports.