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Scavenger cells help limbs to regrow ^ | 5/21/13 | Clare Pain

Posted on 05/21/2013 11:35:15 AM PDT by LibWhacker

A scavenging immune system cell that helps limbs regrow in salamanders brings hope that humans will one day be able to mimic the animal's amazing regenerative powers, say Australian researchers.

The findings by Dr James Godwin, of the Australian Regenerative Medicine Institute at Monash University, and colleagues, are published in today's issue of the Proceedings of the National Academy of Sciences.

Salamanders (axolotls) are unique amongst vertebrates in being able to repair their hearts, tails, spinal cord and brain, and even regrow whole limbs during adult life, says Godwin.

He sees their "perfect regeneration" as a holy grail. "We're trying to work out what the requirements are so we can unlock that potential in mammals," he says.

Not just gobblers

He has suspected for a while that macrophages, cells involved in the immune system, might be important in the regeneration process.

Macrophages are a major immune cell type which roam the tissues engulfing invaders like bacteria and fungi, explains Godwin.

"But they're not just involved in gobbling up debris. They actively determine repair - for example they are important in human muscle repair," he adds.

"So we asked the question - are macrophages needed for limb regeneration?," he says.

When the team got rid of the macrophages in the salamanders, it had a "devastating effect" on their ability to regrow limbs. The animals ended up with fibrosis (scarring) and a stump.

Godwin believes that chemicals released by the animals' macrophages are essential for the regeneration process, and is conducting experiments now to investigate this.

"This really gives us somewhere to look for what might be secreted into the wound environment that allows for regeneration," he says.

"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."

Scar-less healing

Commenting on the study, Dr Andràs Simon of the Karolinska Institute in Sweden says "There has been a lot of discussion about how cells of the immune system might impinge on the regenerative process.

"No one has experimentally addressed this before, so in that sense it's very important."

He says the work has implications not just for entire limb regrowth, but for "smaller, less ambitious" goals such as scar-less healing.

Although scars perform a useful function in stopping blood loss and preventing infection getting into a wound, they inhibit communication between cells and this prevents regeneration, says Simon.

Down the track, using the salamander's approach could maybe help with healing of burns, for instance, he suggests.

Lost in the lottery?

But why has evolution lost such a seemingly useful capacity as the ability to regrow a whole limb?

Godwin says he is speculating, but formation of scars to prevent blood loss and infection may have been vital for mammals which are constantly on the move.

Or we could have just been unlucky in the "evolutionary lottery" he says. "Sometimes things just get lost."

TOPICS: Health/Medicine; Science
KEYWORDS: cells; immune; limbs; regenerative; regrow; salamanders; scavenger; system

1 posted on 05/21/2013 11:35:15 AM PDT by LibWhacker
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To: neverdem


2 posted on 05/21/2013 11:38:32 AM PDT by airborne (MY HEROES DON'T WEAR CAPES. MY HEROES WEAR DOG TAGS ! ! !)
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To: LibWhacker

Just had to include this classic gem.

From MAD magazine #43, 1958:

I Wandered Lonely as a Clod

I wandered lonely as a clod,
Just picking up old rags and bottles,
When onward on my way I plod,
I saw a host of axolotls;
Beside the lake, beneath the trees,
A sight to make a man’s blood freeze.

Some had handles, some were plain;
They came in blue, red pink, and green.
A few were orange in the main;
The damndest sight I’ve ever seen.
The females gave a sprightly glance;
The male ones all wore knee-length pants.

Now oft, when on the couch I lie,
The doctor asks me what I see.
They flash upon my inward eye
And make me laugh in fiendish glee.
I find my solace then in bottles,
And I forget them axolotls.

3 posted on 05/21/2013 11:47:16 AM PDT by yefragetuwrabrumuy (Best WoT news at
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To: airborne; KC_Lion

Oh this will work out....

4 posted on 05/21/2013 11:48:23 AM PDT by GraceG
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To: GraceG

Eh, I really didn’t like that movie anyway. ;P

5 posted on 05/21/2013 12:10:33 PM PDT by KC_Lion (Build the America you want to live in at your address, and keep looking up.-Sarah Palin)
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To: yefragetuwrabrumuy

Is it to be sung to any particular tune?

6 posted on 05/21/2013 12:21:50 PM PDT by Oratam
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To: Oratam

In their early years, MAD Magazine did both parody and satire poems and songs. In this case, the poem “I wandered lonely as a cloud”, by William Wordsworth, which has long been a target for parody.

My favorite parody version of it used a very restrictive form of parody, only changing a single unique word in a poem, in this case, changing the word “daffodils”, to “imbeciles”. It was brilliant:


I wandered lonely as a cloud
That floats on high o’er vales and hills,
When all at once I saw a crowd,
A host, of golden imbeciles;
Beside the lake, beneath the trees,
Fluttering and dancing in the breeze.

Continuous as the stars that shine
And twinkle on the milky way,
They stretched in never-ending line
Along the margin of a bay:
Ten thousand saw I at a glance,
Tossing their heads in sprightly dance.

The waves beside them danced; but they
Out-did the sparkling waves in glee:
A poet could not but be gay,
In such a jocund company:
I gazed-—and gazed-—but little thought
What wealth the show to me had brought:

For oft, when on my couch I lie
In vacant or in pensive mood,
They flash upon that inward eye
Which is the bliss of solitude;
And then my heart with pleasure fills,
And dances with the imbeciles.


7 posted on 05/21/2013 1:08:00 PM PDT by yefragetuwrabrumuy (Best WoT news at
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To: yefragetuwrabrumuy

Brilliant. I’m in tears. Thanks!

8 posted on 05/21/2013 2:07:49 PM PDT by Oratam
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