NEW YORK =97 Researchers are trying to find ways to regrow fingers =97
and someday, even limbs =97 with tricks that sound like magic spells
from a Harry Potter novel.
There's the guy who sliced off a fingertip but grew it back, after he
treated the wound with an extract of pig bladder. There are also the
scientists who grow extra arms on salamanders, and the laboratory mice
with the eerie ability to heal themselves.
This summer, scientists are planning to see whether the powdered pig
extract can help injured soldiers regrow parts of their fingers. A
large federally funded project is trying to unlock the secrets of how
some animals regrow body parts so well, with hopes of applying the the
lessons to humans.
=95 Click here to visit FOXNews.com's Human Body Center.
The implications for regrowing fingers go beyond the cosmetic. People
who are missing all or most of their fingers, as from an explosion or
a fire, often can't pick things up, brush their teeth or button a
button.
If they could grow even a small stub, it could make a huge difference
in their lives.
The lessons learned from studying regrowth of fingers and limbs could
aid the larger field of regenerative medicine, perhaps someday helping
people replace damaged parts of their hearts and spinal cords, and
heal wounds and burns with new skin instead of scar.
But that's in the future. For now, consider the situation of Lee
Spievack, a hobby-store salesman in Cincinnati, as he regarded his
severed right middle finger one evening in August 2005.
He had been helping a customer with an engine on a model airplane
behind the shop. He knew the motor was risky because it required
somebody to turn the prop backwards to make it run the right way.
"I pointed to it," Spievack recalled the other day, "and said, 'You
need to get rid of this engine, it's too dangerous.' And I put my
finger through the prop."
He'd misjudged the distance to the spinning plastic prop. It sliced
off his fingertip, leaving just a bit of the nail bed. The missing
piece, three-eighths of an inch long, was never found.
An emergency room doctor wrapped up the rest of his finger and sent
him to a hand surgeon, who recommended a skin graft to cover what was
left of his finger. What was gone, it appeared, was gone forever.
If Spievack, now 68, had been a toddler, things might have been
different. Up to about age 2, people can consistently regrow
fingertips, says Dr. Stephen Badylak, a regeneration expert at the
University of Pittsburgh. But that's rare in adults, he said.
Spievack, however, did have a major advantage =97 a brother, Alan, a
former Harvard surgeon who'd founded a company called ACell Inc., that
makes an extract of pig bladder for promoting healing and tissue
regeneration.
It helps horses regrow ligaments, for example, and the federal
government has given clearance to market it for use in people. Similar
formulations have been used in many people to do things like treat
ulcers and other wounds and help make cartilage.
The summer before Lee Spievack's accident, Dr. Alan Spievack had used
it on a neighbor who'd cut his fingertip off on a tablesaw. The man's
fingertip grew back over four to six weeks, Alan Spievack said.
Lee Spievack took his brother's advice to forget about a skin graft
and try the pig powder.
Soon a ****pment of the stuff arrived and Lee Spievack started applying
it every two days.
Within four weeks his finger had regained its original length, he
says, and in four months "it looked like my normal finger."
Spievack said it's a little hard, as if calloused, and there's a
slight scar on the end. The nail continues to grow at twice the speed
of his other nails.
"All my fingers in this cold weather have cracked except that one," he
said.
All in all, he said, "I'm quite impressed."
None of this proves the powder was responsible. But those outcomes
have helped inspire an effort to try the powder this summer at Fort
Sam Houston in San Antonio, on soldiers who have far more disabling
finger loss because of burns.
Fingers are particularly vulnerable to burns because they are small
and their skin is thin, says David Baer, a wound specialist at the
base who's working on the federally funded project.
The five to 10 patients in the project will be chosen because they
have major losses in all their fingers and thumbs, preventing them
from performing the pinching motion they need to hold a toothbrush,
for example.
The soldiers will have the end of a finger stub re-opened surgically,
with the powder applied three times a week.
Nobody is talking about regrowing an entire finger. The hope is to
grow enough of a finger, maybe even less than an inch, to do pinching.
It is just a hope.
"This is a real shot in the dark," says Badylak, who's participating
in the project. "There's literally nothing else these individuals have
to try. They have nothing to lose."
But from a scientific standpoint, he said, "this isn't ready for prime
time."
For one thing, it's not completely clear what happened inside Lee
Spievack's finger.
The broad outline is pretty straightforward. The powder is mostly
collagen and a variety of substances, without any pig cells, said
Badylak, who's a scientific adviser to ACell. It forms microscopic
scaffolding for incoming human cells to occupy, and it emits chemical
signals to encourage those cells to regenerate tissue, he said.
Those signals don't specifically say "make a finger," but cells pick
up that message from their surroundings, he said.
"We're not smart enough to figure out how to regrow a finger," Badylak
said. "Maybe what we can do is bring all the pieces of the puzzle to
the right place and then let Mother Nature take its course."
But "we are very uninformed about how all of this works," Badylak
said. "There's a lot more that we don't know than we do know."
Some animals, of course, can regenerate tissue without help from any
powder. Badylak and other scientists are involved in a separate,
Pentagon-funded project to uncover and harness their secrets. This
work might someday lead to regenerating entire limbs.
One animal they're studying is the salamander, a star of the
regeneration field. Chop off a salamander's arm, and it will grow back
in a matter of weeks.
Why? The short answer is that rather than making a scar to heal
quickly, as people do, the salamander forms a mound of cells called a
blastema.
This is a regeneration factory: If you cut off a salamander hand and
transplant the resulting blastema to the creature's back, it will grow
out a hand there.
David Gardiner at the University of California, Irvine, is studying
the secrets of the salamander by growing extra arms on the creatures.
That allows for more controlled conditions than amputating arms and
trying to follow what happens, he said.
So how do you make a salamander grow an extra arm? Make a shallow
wound on the upper arm. Re-route a nerve to the site so it will pump
out critical chemical signals that promote the creation of blastema
cells. Then insert a tiny piece of skin from the other side of the
limb you just wounded, to help provide a blueprint for what needs to
be done.
The recipe sounds like "you put it in a cauldron under a full moon,"
Gardiner observed.
The creatures are so lethargic it's hard to tell if they can use their
extra arms, he noted. But the research shows that beyond establi****ng
a blueprint for a new arm, this mix of cells sends out a chemical
S.O.S. to attract other kinds of cells from the salamander's body to
help construct a new appendage.
Just how many chemical signals are involved, and what they are, remain
to be discovered.
Then there's the specially bred mouse strain that befuddled Ellen
Heber-Katz a decade ago, and has since become a focus of her research.
Heber-Katz, of the Wistar Institute in Philadelphia, was using the
mouse strain known as MRL in a study of autoimmune diseases. Her team
punched tiny holes in the animals' ears as markers. About three weeks
later, Heber-Katz noticed a troubling thing.
"There were no ear holes," she recalled the other day. "We ear-punched
again, and they closed up and disappeared.... We were just so
shocked."
Like salamanders, the mice were growing blastemas instead of scars.
They also heal damage to their hearts.
But for regrowing digits, even this mouse falls short. If a toe is cut
off at some point other than the tip, the remnant produces a cell mass
that looks like a small blastema, but it doesn't grow the missing part
back. (An ordinary mouse just develops a scar.)
At least, the MRL mouse "looks like it's trying," Heber-Katz said.
In studying the mice and salamanders, scientists will pursue several
questions. What genes rev up to produce regrowth? What biochemical
signals are involved? What is the role of specific cells? Can this
knowledge be used to regrow a digit on a mouse?
Scientists say it's not clear when this research might help people.
As for Spievack, the model-airplane enthusiast, he's had enough
personal experience in this area.
"I don't plan on cutting anything more off to find out if I can grow
that back," he said.
http://www.foxnews.com/story/0,2933,252704,00.html
Dragonblaze
- Faith cannot move mountains, but look what it can do to
skyscrapers!. -
|
