“I got better.”
Armed with the stunning ability to regenerate limbs, eyes, hearts, spinal cords, intestines, and even its upper and lower jaws, newts are the masters of regeneration. Thanks in part to the initial illuminating studies of Italian biologist Lazzaro Spallanzani conducted over 200 years ago, we’ve known for a while that newts and salamanders had this special gift.
As science and technology progressed, biologists learned more about the ability of the cells at the site of the injury to de-differentiate, rapidly reproduce and differentiate again to grow a new organ or limb. But it’s always been unclear the lengths these abilities could stretch to.
In a study spanning 16 years, Panagiotis Tsonis, along with his team, concludes that the healing ability of newts remain unaffected by injury and age, debunking 250 years of scientific theory about a fundamental element of tissue regeneration – that age and repeated amputation negatively affect regeneration.
As director of the University of Dayton’s Center for Tissue Regeneration and Engineering at Dayton (TREND), Tsonis believes that his discovery will benefit the progressive field of regeneration research, bringing biologists and the medical community one step closer to a complete understanding of the mechanism behind newt regeneration. One day, he believes, humans will be fully able to replicate the process for themselves.
Tsonis’ mentor and co-author of the study Goro Eguchi set up the experiment in 1994, after collecting several Japanese fire-bellied newts (Cynops pyrrhogaster), successfully keeping them in captivity, and over time anesthetising the newts and carefully removing the lenses from their eyes. The team focused on the newt’s lens– it’s unique in that it can be removed entirely and regenerates in a completely enclosed environment after the incision in the cornea heals within a day.
To remove the lens, a small nick to the cornea was made, which quickly sealed, forming a protective environment so that the lens could regenerate without the disruption of any outside influence. And do you know how many times he did this? 18 times in total, with newts that were estimated to be at least 14 years old when collected, making them 30 by the end of the study.
The outstanding thing: The 17th and 18th regenerated lenses of each newt were virtually identical to intact lenses from full-grown newts!
With these repeated surgeries throughout a span of 16 years, and with the oldest newts regenerating their lens as well as the young ones, the team proved the long-held belief that regeneration capabilities are adversely affected with age to be false.
“We are still a long way from relating this to humans, but what this shows is that the newt is an excellent source for finding answers to regeneration, particularly as it relates to old age,” Tsonis said. “The newt not only has good regeneration properties, but it has the ability to protect and preserve regeneration.”
If you haven’t seen him explain newt regeneration himself, check it out here!
“I expected to see regeneration in the final trials, but this good? Even I was surprised a little. It was a perfect lens,” Tsonis said. “As a biologist, I can say this is the biggest discovery in regeneration research involving newts in 250 years.”
The next step? Discover how newts keep their regenerative potential in their ageing tissues so that the new understanding can be applied to human medicine. It won’t be an easy task, since newts and salamanders are notoriously difficult to work with in captivity, but Tsonis’s group are working hard and remain optimistic. “Our findings… are of paramount importance to the field of regeneration and ageing,” Egochi writes.
“We and others have invested a lot of effort to develop these techniques. Many important questions can now be addressed to understand why newts do what they do and how to apply it to regenerative medicine. After all, this animal does everything that regenerative medicine seeks to achieve!”
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Eguchi, Eguchi, Nakamura, Yadav, Milan & Tsonis. 2011. “Regenerative capacity in newts is not altered by repeated regeneration and ageing”. Nature Communications. http://dx.doi.org/10.1038/ncomms1389
“Ageless Regeneration.” University of Dayton News. University of Dayton, 12 June 2100. Web. 20 July 2011. http://www.udayton.edu/news/articles/2011/07/tsonis_regeneration_research.php.
Young, Ed. “Newt Healing Factors Unaffected by Age and Injury.” Discover. Kalmbach Publishing Co., 12 July 2011. Web. 22 July 2011. http://blogs.discovermagazine.com/notrocketscience/2011/07/12/newt-healing-factors-unaffected-by-age-and-injury/.