Team studied patient who had part of a rib removed

Eight cm of missing bone and one centimeter of missing cartilage repaired in just six months

While we may not quite have the regenerative powers of a superhero, humans are surprisingly adept at regrowing ribs, researchers have found.

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Researchers have analysed the capabilities in mice after spotting a human subject who was able to regrow part of a rib.

The team found that mice and humans were able to regrow removed ribs within months.

The team found that mice and humans were able to regrow removed ribs within months - and could be used in treating osteoporosis and other skeletal disorders.

WHY DO WE HAVE RIBS? The function of ribs is threefold. First, they provide protection for the lungs and heart, forming a 'cage' around them. Second, they are one of the few bones that continue to make red marrow (and thus blood cells) in adults. They also serve as attachment points for chest muscles involved in respiration.

In a new study in the Journal of Bone and Mineral Research, a team directed by USC Stem Cell researcher Francesca Mariani studied the phenomenon.

Using CT imaging, the team monitored the healing of a human rib that had been partially removed by a surgeon.

The eight centimeters of missing bone and one centimeter of missing cartilage did partially repair after six months.

To better understand this repair process, they removed sections of rib cartilage — ranging from three to five millimeters — from a related mammal, mice.

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When they removed both rib cartilage and its surrounding sheath of tissue — called the 'perichondrium,' the missing sections failed to repair even after nine months.

However, when they removed rib cartilage but left its perichondrium, the missing sections entirely repaired within one to two months.

The researcher could lead to new therapies for skeletal regeneration elsewhere in the body

They also found that a perichondrium retains the ability to produce cartilage even when disconnected from the rib and displaced into nearby muscle tissue — further suggesting that the perichondrium contains progenitor or stem cells.

'We believe that the development of this model in the mouse is important for making progress in the field of skeletal repair, where an acute clinical need is present for ameliorating skeletal injury, chronic osteoarthritis and the severe problems associated with reconstructive surgery,' said Mariani, assistant professor of Cell and Neurobiology and principal investigator in the Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research at USC.

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'At the early stages in our understanding, the mouse provides us with an exceptional ability to make progress, and we are excited about the potential for using cells derived from the rib perichondrium or using rib perichondrium-like cells for regenerative therapy.'