The ability for mammals to regenerate damaged tissue without scarring has been demonstrated for the first time by a research team based at the Wistar Insitute, Philadelphia. Their findings were published in the Proceedings of the National Academy of Sciences last week.
The research team showed that holes punched into the ears of mice lacking a gene known as 'p21' (a common method of identifying lab animals) had completely healed after a few weeks.
'Much like a newt that has lost a limb, these mice will replace missing or damaged tissue with healthy tissue that lacks any sign of scarring' said Professor Ellen Heber-Katz, who led the study.
'While we are just beginning to understand the repercussions of these findings, perhaps one day we'll be able to accelerate healing in humans by temporarily inactivating the p21 gene,' she added.
The ability to regenerate multiple tissues or an entire limb is common among certain creatures, such as the newt. However, such capacity is rare in mammals. Although a human liver can re-grow to full size after most of it is taken away, mammals are not in normal circumstances able to re-grow appendage tissue, such as a finger or ear.
One potential drawback is that the p21 gene also acts as an anti-cancer safety mechanism, blocking cell division in the presence of DNA damage. Mice lacking p21 might therefore be expected to suffer damage to DNA, which in turn could be propagated through further cell divisions, eventually leading to cancer. In the study, increased DNA damage was observed in the mice but there was no cancer surge. Rather, the scientists found an increase in 'cell suicide', or apoptosis, another cancer-blocking mechanism that directs dysfunctional cells to kill themselves.
'The combined effects of an increase in highly regenerative cells and apoptosis may allow the cells of these organisms to divide rapidly without going out of control and becoming cancerous,' said Professor Heber-Katz.
Whilst this is a significant finding, these results will need to be repeated in human tissue. Even then, it will be many years before this and further work allows us to re-grow entire human limbs, as the Daily Express and the Mirror newspapers claimed might be possible.
'It's part of the jigsaw for how we would get major organs and limbs to repair. But we will need decades of work until we get the full effect. In the shorter term this might be used for treatments such as skin and connective tissue repair - such as getting a wound to repair without forming a scar,' said Professor Kevin Shakesheff, Head of the School of Pharmacy at Nottingham University.