Science News

Rare salamander's healing ability could soon help humans

By Christina Sticht Feb 28, 2011, 16:46 GMT

Hanover, Germany - The aquatic axolotl is not unduly bothered if it loses a leg or tail since when a limb or appendage becomes detached from this cute-looking Mexican mole salamander, the creature simply grows a new one. The remarkable regeneration leaves no scar and even heart, spinal or serious brain defects can be dealt with in the same way.

'There is no such thing as a paralysed axolotl,' says molecular biologist Katrin Reimers-Fadhlaoui who works at the Medical High School in Hanover. For seven years now Reimers-Fadhlaoui and a group of surgeons and amphibian experts have been studying the Ambystoma mexicanum and its unusual abilities.

The college's clinic for plastic surgery and regenerative medicine has recently opened an axolotl research centre and in a laboratory colony between 70 and 80 dark grey, white and gold-coloured mole salamanders patiently await inspection.

'They really are very affectionate,' says breeding expert Christina Allmeling, who points out that conditions are right for the survival of this amphibian species which has all but died out in the wild.

At feeding time the axolotl lifts its limbs, as if waving. The original habitat of the animal in Mexico has been largely destroyed by urban encroachment and contaminated water but axolotl and his kind have been given a new lease of life, thanks to their capability of repairing themselves.

'We hope to be able to help millions of patients worldwide who suffer from poor or delayed healing,' said surgeon Bjoern Menger. Diabetics, elderly people, those who have received serious burns or the war-wounded all stand to benefit from the findings.

Menger has amputated individual axolotl limbs under general anesthetic although the creatures have also been supplying research material of their own. 'Amputations as a result of bite injuries are an almost daily occurrence. The fascinating thing is even severe wounds congeal within seconds,' said Menger.

The researchers in Hannover have been trying to understand the complex healing processes by studying the genome sequence of the axolotl's regeneration tissue. While doing so they came across an enzyme called AmbLOXe which seems to trigger the process.

In experiments with cell cultures they were able to show that AmbLOXe is capable of significantly enhancing the capability of skin cells to reproduce. The findings were published in December last year in the medical journal Annals of Surgery. Initial experiments using mice also proved successful.

'We aim to carry over these results to human beings as soon as possible,' said Reimers-Fadhlaoui. She envisages a lotion which could be used universally to aid human healing processes. It may several years, however, before clinical trial success translates into a remedy available to all.

Menger is also the force behind a project planned for the accident surgery wing of Germany's Goettingen University. It revolves around bone fractures which normally take an abnormally long time to heal.

Researchers are optimistic that the regenerative capabilities of amphibians are buried somewhere within human DNA, the nucleic acid which contains the genetic instructions used in human development. The ability is currently inactive but doctors believe it could be restored. They point to the human baby's ability in the womb to heal injury without leaving behind a scar.

Axolotl cells have been observed to behave in a similar way to the cells of mammals, researchers at the DFG Research Centre for Regenerative Therapy in Dresden discovered. They wrote up their observations in the scientific magazine Nature.

Despite the axolotl's built-in repair shop, the amphibian is not capable of stopping the ageing clock. 'The regeneration can be repeated but the animals are not capable of overhauling themselves completely on as regular basis,' says Reimers-Fadhlaoui.

The moles get older like every other animal as shown by a 16-year-old example known as 'Tiger Girl.' This axolotl enjoys a quiet life in the laboratory but is hardly a fountain of youth. The creature is very wrinkled and lacks energy.