Lab-grown human limbs may be closer to reality

Scientists in US are attempting to grow the world's first primate 'bio-limb' for a macaque, with the aim that the procedure may ultimately be used for human amputees.
Scientists in Boston led by Harald Ott, an Austrian surgeon, have previously been successful in growing a limb for a rat in the lab.
Ott's lab, which is in the grounds of Massachusetts General Hospital, has grown the cells of organs, including kidneys and the heart, but a limb, with its multiple layers of muscle, tissue and nerves, is far more complex.
Ott developed a technique as a research fellow at the University of Minnesota, in which a donor limb is stripped of its soft tissues using a powerful detergent.

This process, known as decelluraisation, leaves a 'scaffold' of the limb; the collagen structures that make up blood vessels, tendons, muscles and bones.
Researchers then attempt to grow new cells to repopulate this structure, using 'progenitor' cells that can be effectively programmed to form blood or muscle cells, 'The Times' reported.

"Once the cells go into the organ, they have to sit down, find their neighbours, attach to their neighbours and continue to proliferate," said Lisa Fitzgerald, the laboratory manager.
This takes place in a bioreactor, a custom-designed container which supplies nutrients, oxygen and electrical stimulation to the limb as it reforms.

Having successfully created a rat limb using this technique, with muscle which responded to electrical stimulation, Ott believes that it ought to be possible to scale the experiment up to the limb of a primate.