TRANSPLANT PROGRAMS
YOUNG AT HEART
THE WIDE, LARGELY UNEXPLORED WORLD
OF PEDIATRIC HEART FAILURE
When a child who needs a
transplant gets a new heart,
what happens to the old one?
At Children’s Hospital Colorado,
it’s deposited (with the parent’s
permission, of course) into a
bank of diseased heart tissue
that researchers like Children’s
Colorado transplant cardiologist
Shelley Miyamoto, M.D., have been
amassing for more than 20 years.
SHELLEY
MIYAMOTO, M.D.
In extreme deep freeze, the heart’s
cells can stay intact for a very long
time. Even many years later, lab
technicians can slice heart tissues
into strips just a few micrometers
thick and lower them into baths of
medicine to test the effects of a
possible drug for pediatric heart
failure — something that, right now,
does not exist.
In fact, only one drug trial for heart
failure in children has ever been
conducted. “And the shocking thing
about that trial,” says Dr. Miyamoto,
“was that this drug had been proven
in multiple trials to be effective in
adults, but in children it produced
no improvement.”
Children’s hearts fail for many
reasons, most of them congenital.
It’s an array of rare diseases few
researchers study. Dr. Miyamoto
is one of the few researchers in
the world who does. Working with
University of Colorado School of
Medicine adult cardiologist Brian
Stauffer, M.D., and molecular
biologist Carmen Sucharov, Ph.D.,
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Dr. Miyamoto uses lab techniques
and clinical data to compare child
and adult heart disease at the
molecular level.
The differences are crucial: a heart
drug called milrinone, for example,
is dangerous when used chronically
in adults. Dr. Miyamoto’s team
recently proved it safe and effective
in children even over a long period
of time — a period, say, like the
protracted, uncertain wait on the
transplant list. The distinction could
save lives.
“It hasn’t worked to
extrapolate from the
adult data,”
Dr. Miyamoto says. “There’s been
no improvement in transplant-free
survival for kids in 30 years, and
that’s not okay.”
That could change. Dr. Miyamoto’s
team was recently the first to
describe the role of non-coding
proteins called micro-RNAs as
biomarkers of potential heart
recovery: the relative presence of
these proteins in diseased hearts
predicts recovery an astonishing
66 to 88 percent of the time.
That power to predict could go a
long way toward subverting the
enormous burden of waiting for
a transplant.
The relative
presence of these
proteins in diseased
hearts predicts recovery
an astonishing 66 to 88
percent of the time.
“The pediatric field is lagging far
behind the adult field,” says Dr.
Miyamoto. “But it’s a start.”
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