How to grow a new eye

The radical researchers who believe that amphibians can teach us to regenerate ourselves

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In Zimbabwe, the Eastgate Shopping Centre sprawls across 26,000 square metres: an enlarged urban replica of a termite mound, recreated for its natural cooling system. Similarly, researchers are currently studying how seahorse tails are both armoured and flexible, with the intention of applying such structures to joints in military garb. The emulation of systems, processes and models that appear so effortlessly in nature has long fuelled innovative design, yet science is on the cusp of a new frontier with the application of biomimicry to medical advancement. 

The earliest salamander fossils date back more than 160 million years and its lengthy timespan on Earth has earned the amphibian an evil-ridden reputation. Born from fire, the creature has roamed the pages of popular culture for hundreds of years, a friend to dragons and basilisks alike.  More unlikely still — and the only fact in an ocean of elaborate fiction — is the salamander’s ability to amputate its own tail at will. Loss of limb for a human is an unimaginably life-changing fate, but this last resort defence mechanism enables the lizard-like creature to escape its enemy, free to repair itself over a course of weeks.

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Salamanders’ ability to regrow parts of the brain, heart and spinal cord has inspired scientists to question how the process could be applicable to humans

Described as “perfect” regeneration, salamanders’ ability to regrow most parts of the anatomy — including parts of the brain, heart and spinal cord — has inspired scientists to question how the process could be applicable to humans. A paper recently submitted to the Proceedings of the National Academy of Sciences claims the answer may lie in the amphibian’s immune system.

Project leader Dr. James Godwin and his colleagues at Australia’s Monash University have discovered that the presence of macrophages — an immune system cell, which also exists in humans — is integral to the regenerative process. The team discovered this after removing all macrophages from the aquatic salamander species they were working with. The study cites, “Systemic macrophage depletion … resulted in wound closure but permanent failure of limb regeneration.” After the cells were reintegrated into the test subjects, the stumps were re-amputated and limbs grew back as new.

“Previously, we thought that macrophages were negative for regeneration,” commented Dr. Godwin in a recent statement. “This research shows that this is not the case: if the macrophages are not present in the early stages of healing, regeneration does not occur.” In short, the study shows that humans have all the core components necessary for limb regeneration. Godwin and his team believe chemical deployment from the macrophages could hold the key to transition from mammalian scar tissue to amphibious regrowth.

The benefits of potential “therapies” that could shift the immune system onto a regenerative path aren’t limited to amputees, either. Godwin and his team have already stated that a breakthrough in this field could lead to better treatments for diseases of the heart and liver. Yet rapid cell regeneration is an alien concept, a minefield of potential side effects: 20/20 vision could become a universal standard, the aesthetic of aging a distant memory.

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