In experiments that would make Dr. Frankenstein jealous, US scientists have
coaxed recycled hearts taken from animal cadavers into beating in the laboratory
after reseeding them with live cells, according to a study released on Sunday.

If extended to humans, the
procedure could provide an almost limitless supply of hearts, and possibly other
organs, to millions of terminally ill people waiting helplessly for a new lease
on life.

Approximately 50,000
patients in the United States alone die every year for lack of a donor heart,
and some 22 million people worldwide are living with the threat of heart
failure.

"The idea would be to
develop transplantable blood vessels or whole organs that are made from your own
cells," said lead researcher Doris Taylor, director of the Centre or
Cardiovascular Repair at the University of Minnesota.

While there have been advances
in generating living heart tissue in the lab, this is the first time an entire,
three-dimensional bio-artificial heart has been brought to life.

The core procedure making this
possible is called decellularisation. In this process, all the cells from an
organ — in this case the heart of a dead rat — are stripped away using
powerful detergents, leaving only a bleached-white scaffolding composed of
proteins secreted by the cells.

In the experiments, this
matrix was then injected with a mixture of cells taken from newborn rat hearts
and placed in a sterile lab setting, where the scientists hoped it would grow.

After only four days,
contractions started, and on the eighth day, the hearts were pumping, according
to the study, published in the British journal

Nature
Medicine

.

The researchers were stunned.
"When we saw the first contractions, we were speechless," said Harald Ott, a
surgeon at Massachusetts General Hospital.

"We certainly were surprised
that it worked so well and so quickly," Taylor said. "There are so many places
this could have gone wrong."

In humans the objective would
be to inject stemcells drawn directly from the recipient of the donated organ,
thus eliminating the danger that the new heart would be rejected by the immune
system.

Recent breakthroughs
in stemcell research from non-embryo sources mean that new tissues should be
easy to generate, according to the authors.

Many patients who might one
day benefit from a transplanted bio-artificial organ are currently not even
listed as potential recipients, said Ott.

"If organs derived from a
patient’s own cells would become available on a large scale — maybe even as an
off-the-shelf product — millions of patients suffering from organ failure would
benefit," he said in an e-mail.

In these "proof of concept"
experiments, the bio-artificial rat hearts grown in the lab pumped, after eight
days, with a force equivalent to about two percent of an adult rodent heart.

Taylor and her team are now
working on making the recycled organs more efficient, and have even transplanted
some of these hearts into the abdomens of rats and connected them to the
animals’ aortas, a standard way of testing whether a donor organ can keep an
animal alive.

Decellularisation could change
the way scientists thinks about engineering organs, according to the study.

"It opens a door to this
notion that you can make any organ: kidney, liver, lung, pancreas — you name it
and we hope we can make it," Taylor said.

Though not reported in this
study, the Minnesota researchers have also successfully applied the technique to
pig hearts, which are closer to human hearts in size and complexity.

Via Times of India