Macrophages let salamanders replace limbs
MONASH U. (AUS) — Salamanders can regrow limbs thanks to their immune systems, which could also play a role in the regeneration of their spinal cords, brain tissue, and even parts of their hearts.
As reported in the Proceedings of the National Academy of Sciences, researchers found that when immune cells known as macrophages were systemically removed, salamanders lost their ability to regenerate a limb and instead formed scar tissue.
The findings brought researchers a step closer to understanding what conditions were needed for regeneration says lead researcher, James Godwin, a fellow in the laboratory of Nadia Rosenthal, director of the Australian Regenerative Medicine Institute at Monash University.
“Previously, we thought that macrophages were negative for regeneration, and this research shows that that’s not the case—if the macrophages are not present in the early phases of healing, regeneration does not occur,” Godwin says.
“Now, we need to find out exactly how these macrophages are contributing to regeneration. Down the road, this could lead to therapies that tweak the human immune system down a more regenerative pathway.”
Salamanders deal with injury in a remarkable way. The end result is the complete functional restoration of any tissue, on any part of the body including organs. The regenerated tissue is scar free and almost perfectly replicates the injury site before damage occurred.
“We can look to salamanders as a template of what perfect regeneration looks like,” Godwin says.
Aside from “holy grail” applications, such as healing spinal cord and brain injuries, Godwin believes that studying the healing processes of salamanders could lead to new treatments for a number of common conditions, such as heart and liver diseases, which are linked to fibrosis or scarring. Promotion of scar-free healing would also dramatically improve patients’ recovery following surgery.
There are indications that there is the capacity for regeneration in a range of animal species, but it has, in most cases been turned off by evolution.
“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,” he says.
“We need to know exactly what salamanders do and how they do it well, so we can reverse-engineer that into human therapies.”
Source: Monash University
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