July 2, 2009

Salamander Regeneration Possible For Humans?

The salamander is known for its regeneration, as it can replace lost limbs, lungs, its spinal cord, and even parts of its brain that it has lost.

New research says that the unique ability might one day be duplicated by scientists to use in humans.

Until now, biologists have credited the regeneration to the salamander's "pluripotent" cells, which surge to the area of amputation, or a blastema, and act like human stem cells in their versatility.

Pluripotent cells are persuaded by signals into moving into the tissues that comprise skin, bone, nerves, muscle and so on and repairing what was lost.

However, a team of researchers has rejected that idea. From experiments conducted on genetically modified salamanders, the researchers indicates that cells from the different tissues keep the "memory" of the lost tissues, creating the same kind of tissue that was once there.

In other words, the "old" muscle cells create the new cells, the "old" nerve cells make the new cells, and the "old" skin cells make the new cells.

Mammal stem cells work the same way, although it is not as dramatic: they heal wounds or knit bones, but do not regenerate limbs or heal spinal cords. The exciting thing about the new study is it implies that using the salamander's regenerative powers is a possibility for human medical science.

"I think it's more mammal-like than was ever expected," said Malcolm Maden, a professor of biology, member of the UF Genetics Institute, and writer of the paper. "It gives you more hope for being able to someday regenerate individual tissues in people."

Maden feels like the study will help researchers target why salamander cells can regenerate.

"If you can understand how they regenerate, then you ought to be able to understand why mammals don't regenerate," he said.

A lot of work lies ahead, however, before salamander-like regeneration is a possibility for humans.

Maden noted that UF researchers would be experimenting on transgenic axolotls as a part of the "The Regeneration Project," in hopes to treat the human brain and other diseases by reviewing regeneration in salamanders, newts, starfish and flatworms.

His paper will appear Thursday in the journal Nature.

In a commentary, in the journal Nature, University of Utah neurobiologist Alejandro Sanchez Alvarado called the study remarkable for unveiling "a new dimension to our understanding of regeneration."

"Like all important work, it also leaves us with questions that will probably occupy researchers for the next few years," he said.


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