A 10 year old British boy has become the first child in the world to receive a transplanted organ that is being rebuilt inside his body using his own stem cells.

Doctors hailed the surgery as a milestone in the development of regenerative medicine, bringing closer the prospect of replacing damaged or worn-out organs with functioning replacements that are not rejected by the body or of treating damaged organs in situ with stem cells to stimulate self repair.

The nine hour operation was carried out at Great Ormond Street Hospital, London, last week by a British and Italian team of specialists. Doctors said that the boy, who has not been identified, was out of bed, breathing freely and speaking.

Martin Birchall, a specialist in regenerative medicine at …