Could we regrow limbs in the future? Marek R. Swadzba

There are many impressive creatures in the natural world. While we as humans have become the apex predator across the entire world, we still have a lot to learn from these creatures. When you look at some of the amazing things that animals do that we can’t you can’t help but wonder if we could steal some tricks from them. Some animals run incredibly fast, others fly. Some animals can jump super high, others can hibernate for months. We have already learned a lot from animals but there is more work to do. Now scientists are studying salamanders and lizards in the hopes of learning all about regrowing lost limbs.

I know, I know, that does seem like a stretch. We as a human race a long way from regrowing our limbs naturally. If we want to copy nature there are probably easier things to emulate than that. But that would be pretty cool. Salamanders can grow back entire limbs, starfish too, lizards can grow back their tail if it gets removed. If humans could do this it would make medical procedures much more straight forward and would save countless lives.

Today we are already benefitting from the things we have learned from nature. Many of the planes we fly were based on learnings from birds. Today we have learned a lot about DNA and vaccines from resurrection plants, as they have shown how these things can be preserved for a long time. Humans are pretty good at regeneration already. While we can’t grow limbs back we do grow hair and nails back at a very fast rate. Couldn’t we just duplicate this gene? We also heal from broken bones and scars over time showing that the body does know how to heal itself. Is it really such a stretch to think that at some point in the future we may be able to regrow limbs?

Scientists at Arizona university are looking into it. They have already published one report that provided the details on how lizards regrow their tails. 302 out of 326 genes required are common in mammals. This means that we have many of the genes that a lizard relies on to grow back limbs. The lizard is the closest genetically to humans. The starfish and the salamander are a lot further apart from us.

Studies have shown that scar tissue is an issue as well. When we get hurt we have cells in place that cover the injury in scar tissue. This means that we can’t generate limbs in that place. Macrophages stop this from occurring. Another gene called Lin28a is also seen as important in the process. It has been found in young animals and promotes better healing. 

Admittedly this shows that we are very far from finding a way to regrow our limbs but all great journeys start with a single step and it appears we have taken ours. We have identified the similarities with animals that can regrow limbs and the important differences. While we can’t use this to start growing limbs right now it still provides a wealth of information that will be useful. The information learned could be used to promote healing in cartilage and muscles, something that we struggle with today.

For those of you that were hoping to read about a way we could grow limbs back, I am sorry, we are just not there yet. The good news is that no one is ruling it out. Actually many people are ruling it out, the good news is that some people who are pretty knowledgable about this stuff are not ruling it out, so why should we. Who knows what amazing leaps the future holds?