Discover - July/August 2011

was a surprise: Seen under the microscope, the surgery site was alive with activity. Disparate cells appeared to be swarming the area in a process that looked similar to an inflammatory response. However, these new arrivals were not blood cells, as you would expect, but something altogether different and unusual.

At first Badylak was puzzled. He knew that the sca;olding could not be the source of the activity, because it had long since broken down. The cause, he realized, had to be the products left behind—molecules, perhaps, that had been lurking within the sca;olding waiting to be released.

Badylak combed the scienti;c literature
for answers. He quickly discovered that
components called cryptic peptides, or
“crypteins,” would explain much of ;;;’s
unique phenomena. Researchers in other
fields had previously discovered that cer-
tain proteins give rise to these hidden pep-
tides when they degrade, and that the pep-
tides have potent antimicrobial e;ects and
important signaling abilities. “Almost every-
body considered the extracellular matrix
just the structural support that allowed you
to stand up and support weight and hold
things together,” Badylak says. “But now we
know it’s almost just the opposite. It’s pri-
marily a collection of signaling proteins and
information that is held within the struc-
tural molecules.”
Badylak understood the recruitment pro-
cess, but he still could not figure out what
the crypteins were recruiting. He went back
to the microscope and watched armies
of cells converge on the site of the broken-
down ;;;. In their number and character-
istics these new arrivals looked nothing like
muscle, nerve, or blood cells. Badylak soon
suspected that the recruits were stem cells,
the all-purpose cells that can develop into
any type of tissue.

He proved it in ;;;; by first X-raying mice to kill off all the stem cells in their bone marrow, then repopulating the bone with stem cells tagged with a fluorescent marker. When he removed a piece of mouse Achilles tendon and added ;;;, ;uorescent stem cells flooded into the area. Months later, some of these tagged cells were still present—implying that some of them had matured into regenerated tissue.

Badylak’s published results caused a stir in the fast-growing ;eld of regenerative medi-

cine, and his professional reputation ;our-ished. To the outside world, however, the researcher remained largely unknown until ;;;;, when an odd confluence of events involving his old friend and collaborator, Alan Spievack, and Spievack’s injured brother catapulted him into the public eye. Spievack, who had coauthored several papers with Badylak, eventually went on to found a company called ACell to market his own special formula of the powder.

;;;;;;;;; ;;;; ;;;; ;;
;at is how Spievack, by then ;;, was in
a position to heal his younger brother, Lee.
When news got out that Lee had regenerated
his fingertip with a mysterious powder he
called pixie dust—and graphic pictures dis-
playing the regenerative process landed on
editors’ desks—a media frenzy erupted. ;e
stories and the photos sparked the imagina-
tion of amputation victims around the world,
including Corporal Isaias Hernandez.

holistically about what risk means.”
Four years later, Badylak still gets several
emails a day asking about his miraculous pixie
dust. Spievack did not get to share in much
of the glory; he died of cancer in May ;;;;.

;;; ;;;; ;;;;;;;’; ;;;;;;;;;;;; ;;;; has finally gone thoroughly mainstream, he is once again seeking to push the outer limits of healing—and is back to square one seeking grants for his far-out research.

Badylak, along with Tufts University biomedical researcher David Kaplan and Susan Braunhut of the University of Massachusetts Lowell, is using a device called a bio-dome, a sleeve with a liquid reservoir that envelops an amputated mouse digit and allows researchers to control the healing environment. What he is trying to do, in a sense, is make us born again. By adding growth factors, liquids such as water and amniotic ;uid, and varying electric currents, he and his colleagues are replicating the conditions that exist in a human embryo—an environment that is perfectly conducive to the transformation of stem cells into the complex tissues that make up a body.

Ropeik says policy makers need to stop issuing reams of statistics and start making policies that manipulate our risk perception system instead of trying to reason with it. Cass Sunstein, a Harvard law professor who is now the administrator of the White House O;ce of Information and Regulatory Affairs, suggests a few ways to do this in his book Nudge: Improving Decisions About Health, Wealth, and Happiness, published in ;;;;. He points to the organ donor crisis in which thousands of people die each year because others are too fearful or uncertain to donate organs. People tend to believe that doctors won’t work as hard to save them, or that they won’t be able to have an open-casket funeral (both false). And the gory mental images of organs being harvested from a body give a de;nite negative a;ect to the exchange. As a result, too few people focus on the lives that could be saved. Sunstein suggests—controversially—“mandated choice,” in which people must check “yes” or “no” to organ donation on their driver’s license application. ;ose with strong feelings can decline. Some lawmakers propose going one step further and presuming that people want to donate their organs unless they opt out.

;e idea of replicating an embryo on the end of a mammal limb to regrow it is considered too unconventional by most peer reviewers. ;e project is still without funding. But Badylak is undeterred. After all, he never let skepticism stop him before.

In the end, Sunstein argues, by normalizing organ donation as a routine medical practice instead of a rare, important, and gruesome event, the policy would short-circuit our fear reactions and nudge us toward a positive societal goal. It is this type of policy that Ropeik is trying to get the administration to think about, and that is the next step in risk perception and risk communication. “Our risk perception is ;awed enough to create harm,” he says, “but it’s something society can do something about.”