Could Humans Regrow Limbs via Macrophages?

For the most part, scientists have focused on salamanders and their capabilities to regrow limbs. Of course, salamanders do this with such perfection as if the injury never happened.

Researchers have focused a great deal on genetics, to see which sequences of genes that people don’t have or is dormant and/or inactivated that contribute to limb regeneration. However, scientists have questioned the debate of could humans regrow limbs with cells of the immune system?

Australian Regenerative Medicine Institute (ARMI)

A group of scientists at the ARMI of Monash University in Australia has been looking at a type of immune cell that is important for inflammation. Along with its role in the clearance of dead and infected cells for its role in limb regeneration.

They published their findings in the Proceedings of the National Academy Sciences in May 2013.

The team was led by Dr. James Godwin, at the University and they conclude that ‘salamander-like’ human limb regeneration is possible. The question researchers have been pondering on, could humans regrow limbs, and the insights focusing around a type of immune cells.

Macrophages

These immune cells called macrophages play an important role in the regenerative process according to Dr. Godwin and his team. Researching into the Axolotl Salamander, using certain drugs that would switch off the macrophages the team found this had a devastating effect on Axolotl’s ability to regenerate. The researchers found that the salamander would scar (Fibrosis) similar to humans.

However, the scientists’ document in their published work that the macrophages were switched back on again then the salamander could regenerate like before. So they believe that these immune cells are key to a certain part of the limb regeneration process.

Could Humans Regrow Limbs?

In humans, these macrophages exist but they do not play a part in regeneration. The team, however, feel that in the salamander these cells release a certain chemical that plays an important part in limb regeneration. They are hoping that perhaps these immune cells could be tweaked in some way to initiate regeneration in mammals.

Dr. Godwin sees this as key to regeneration and is now conducting further research and development, looking at how this may be applied to humans to spur a limb regeneration in the patient. They even suggest they may have a smoking gun and certainly see the Axolotl Salamander as the perfect role model for regeneration.

Along with the objective of reverse engineering by going inside the human body and changing the default mechanism on how the patient responds to a traumatic injury.

As Professor Godwin mentions when being interviewed with ABC news:

“This really gives us somewhere to look for what might be secreted into the wound environment that allows for regeneration…”

“The long-term plan is that we’ll know exactly what cocktail to add to a wound site to allow salamander-like regeneration under hospital conditions.”

Basically what they are saying is that hypothetically the patient would come into the emergency ward and given an exotic medical cocktail internally with a set of drugs or something applied at the injured site.  The patient would then be put on a regenerative pathway during recovery.

“The Doctor Gave Me A Pill And I Grew A New Kidney.”

In the movie Star Trek IV – The Voyage Home from the 1980s, there is a scene where Dr. McCoy gives an elderly lady who is sick with kidney failure, a pill and she grows a new kidney!

I do wonder where these movie producers get their ideas from as it looks like this will no longer be science fiction for much longer!

The scientists point out that looking at a long term agenda, they want to understand precisely what medical cocktail would be required, to apply at the injured site that would invoke salamander-like regeneration under hospital conditions.  The scientific and in-depth research was published in the Proceedings of the National Academy of Sciences or PNAS.

Scar-Free Healing

Less ambitious goals into this research would be the promotion of scar-free healing that would dramatically improve the patient’s recovery time. Something else that the salamander does perfectly.

Scientists also see this scar-free ability, as key in giving radical new treatments for incurable conditions such as limb loss, spinal cord injuries, and heart diseases.

Understanding the Salamander’s scar-free healing wizardry is not just for cosmetic, but also for the healing of organs since when fibrosis (scar tissue) forms it impedes the functioning of the organ.

For instance, fibrosis on the heart is not cardiac muscle and harms the heart’s ability to pump blood. In addition, spinal cord scar tissue does not transmit nerve signals so making it a major factor in paralysis.

Summary

• Researchers have pinpointed cells that are vital for the regenerative process.
• Scientists feel that is could lead to one day tweaking the immune system to allow damaged tissue to regenerate instead of scarring.
• “Some of these regenerative pathways may still be open to us. We may be able to turn up the volume on some of these processes.” – Dr. Godwin.

Let me know your thoughts in the comments below on this research into the Salamander and limb regeneration.