In nature there are many examples of limb regeneration at work. The Mexican Axolotl can regrow its limbs in a matter of weeks, the Gecko Lizard that regenerates a new tail when it sheds it to escape predators. Or how about Newts that are able to pretty much replace whatever type of body tissue that they have lost.
When it comes to the wild the regeneration capabilities of certain creatures are light years ahead of the bio-medical scientific world.
Humans in contrast have very little regenerative capabilities and the best one could hope for is regrowth of a lost finger tip which can happen naturally when very young, but the digit does not normally regenerate during adult years. The liver organ does regenerate but in a limited way. Normally, we just scar (fibrosis) when extreme medical trauma occurs.
New technological innovation in the science of limb regeneration has been revealed by a team of engineers and scientists where they have been able to partially regenerate frogs legs that would only grow back as a small stub or spike under normal conditions without intervention.
This study was led by Michael Levin at the Allen Discovery Center within Tufts University and increases the radical prospects that such an astonishing accomplishment could be applied to human amputees one day.
This is certainly one step closer to developing a practical working solution for limb regeneration. It could well be a game changer.
The group of scientists are hoping that everyone who loses an arm or leg will be able to grow it back in the future. Dr. Michael Levin who is a pioneer in this research feel that limb regeneration will happen during our lifetimes based on an article by Popular Science published back in 2016.
The majority of research into Regenerative Medicine has largely focused on the genome and stem cell research. Not all scientists are convinced of Dr Levin’s analysis that bioelectricity is a primary element of initiating regeneration but more scientists are now taking bioelectricity into focus.
It is worth noting that Levin is one of the scientists whom has the assertion that Dr. Robert O. Becker’s research plays an important part of understanding limb regeneration.
Dr. Becker published his findings in his book The Electric Body: Electromagnetism and the Foundations of Life. Dr. Levin heavily researched Becker’s work in his early days. Tracking down all his papers that his book referenced.
I wrote a comprehensive article in 2015, on humans regenerating body parts with bioelectricity and feel many of the areas of research discussed was ahead of its time, considering what is coming to light now.
For instance, not only did my article focus on Dr. Becker’s work and some of the mechanisms of bioelectricity as a primary trigger for regeneration, but also Dr. Michael Levin was endorsed on his research with using bioelectricity. I wrote the following commentary:
“A delivery vehicle would be a wearable bioreactor that creates an aqueous environment like amniotic fluid. Thus allowing appropriate ion currents causing the injury to be stimulated into regeneration…this would someday allow this [device] to be used in serious limb injuries, most likely starting with regrowing fingers, toes, hands and feet.”
The remaining of this article will follow-up with their latest findings and results of the bioreactor that Dr Levin and his team have produced, that has accomplished in partially regrowing the frog’s limbs.
African Claw Frog
The new successes involve scientists using a certain frog species known as the African claw frog.
This is used as a roadmap for uncharted investigation, and an area of biomedical research that has not been fully explored.
Figuring out how to regrow lost limbs in humans would obviously be revolutionary and for some time now researchers have observed the underlying mechanisms that occur in nature like the creatures I mentioned at the beginning of this article.
The idea is to look for methods that could eventually be applied to humans.
The African Claw Frog is not completely limited in regeneration. During its infant stages as froglets and tadpoles, it can regrow its legs. However, in its adult stage, it loses this ability with only a spikey stump being generated.
The purpose of this work is to look at the feasibility of how new limbs could be regrown in lifeforms that have never possessed regeneration or have lost it.
The core of this research in how to regrow lost limbs is using a device called the progesterone bioreactor, that is worn for stimulation of regeneration.
This bioreactor was developed using 3D Printer technologies from silicon. The device is filled with a sticky polymer gel which contains progesterone, a steroid hormone. It is a substance that has contributed to healing blood vessels, bone tissues and nerves.
Progesterone can also help with the regulation of the bioelectricity state of cells, due to the passing of ions between the outer membranes of these cells, which is believed to initiate regeneration.
The bioreactor is designed to be worn at the site of injury, delivering small molecule compounds, where the frogs’ legs had been removed, using a hydrogel silk based protein.
What Was Regrown?
During a 24 hour period the scientists used the bioreactor to release the progesterone hormone onto the amputated site before the device was removed. These frogs were then studied over a nine to ten-month observation and compared with the same species of frogs that did not have the treatment of the bioreactor.
The result showed that the bioreactor induced a certain level of regrowth of the amputated limb for the group of frogs that had the device fitted and treatment applied. The triggered regeneration ended up with a partially formed limb that had a paddle looking structure containing more well-formed veins, bone tissues and nerves.
This would have not been possible without the medical intervention applied and the group of frogs that did not wear the device or had regeneration treatment only resulted in the stump spike that normally occurs.
This is a major breakthrough as what was regenerated was closer to a fully formed limb. Also, frogs swimming in their tanks were able to do this far better similar to non-amputated frogs.
The use of the bioreactor showed that immune responses and scarring was reduced or restricted, which would suggest that the delivered progesterone was contributing to changing the body’s default mechanisms of responding to the injury.
At the site of amputation, the gene expression in the cells had been changed by the bioreactor based on analysis and opening the pathway to better regeneration.
What if the device had been used for longer, would the limb develop better?
Not so, according to Dr. Levin and his team, 24 hours was long enough to initiate the process of regrowing the leg. They feel that the trick is to improve upon when regeneration starts as their strategy is not trying to micromanage the process but in finding the right combination of coordinates.
New Regeneration Drug
As Levin highlights in New Scientist discussing the team’s findings:
“Your body knows how to make a limb – it did that during embryonic development.”
“The doctor gave me a pill and I grew a new kidney!”,
Star Trek IV – The Voyage Home.
The scientists state that their work shows proof of concept that a brief application of a device that is integrated with the use of drugs, gives a local approach for activating regenerative responses.
Showing that kick-starting regeneration in vertebrate models is possible and opens the door to do the same on animals and eventually humans.
In fact, the team are now looking at how to induce limb regeneration in mammals, however, aquatic creatures are better for analysis of regeneration and repair of injuries.
While research on regeneration in mice have shown that they can partially regenerate including lost digits, but this process is undermined since they move around on the wounded area, in this case, their fingertips.
Thus a water environment is much gentler for the delicate process of regenerating cells.
I know when helping my diabetic cat, it was always difficult to get him to eat at the right time with the right amount of insulin as he would venture outside and catch things.
Too much insulin and he eats too little then the cat would go into a coma, but too little insulin and it will not have the desired effect.
So just like my cat, you cannot explain to the mouse that we are trying to regenerate their fingertips so don’t walk on the injured area!
To summarize, scientists were able to achieve partial regeneration of the frog’s hind limbs using progesterone (a female sex hormone), using the bioreactor – a small box containing the progesterone gel, attached to the injured area.
Is Limb Regeneration Here?
It is a perfectly logical question and I want to address if regeneration of human limbs is actually here.
Continuing on from this work, Levin and his team have started using more complex recipes inside the bioreactor device which has produced even greater compelling results of a better-developed limb being regrown with some toe digits formed.
This is truly amazing.
However, these further breakthroughs have not yet been published according to New Scientist. Once any new research has been peer reviewed and it shows better regeneration of the limb or correctly developed, then indeed this will be very significant.
It clearly shows they are getting ongoing evolving results.
Dr. Levin believes that eventually these techniques can be applied to humans one day which is their ultimate aim.
You could regrow a new limb if the right balance of chemicals is used to create an upgraded version of the bioreactor device.
While limb regeneration is not completely here, it is only a matter of time before it does.
As you can see with Dr. Michael Levin’s work and his additional new research of partially regrowing digits in the frog’s legs.
This will add valuable knowledge and medical insights into the fields of human regeneration across a wide spectrum of research.
So it could well be true that limb regeneration might be here for humans sooner than we think.
The findings of this limb regeneration project done at Tufts University was published in the journal Cell Reports.
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What do you think of this research? I love to know your thoughts. I think we are on a cusp of something major happening in regenerative medicine. Please comment below and share this article with others. I have not seen this kind of great research being acknowledged in the main headline news, pass this article on to all those who are interested.