America
Human 'heart on a chip' to aid drug tests
New York, March 10
for the first time,
scientists - including an Indian American bioengineer - have developed a
network of pulsating cardiac muscle cells housed in an inch-long
silicone device that effectively models human heart tissue.
The team has demonstrated the viability of this system as a drug-screening tool by testing it with cardiovascular medications.
This
organ-on-a-chip represents a major step forward in the development of
accurate, faster methods of testing for drug toxicity.
"Ultimately,
these chips could replace the use of animals to screen drugs for safety
and efficacy," said professor Kevin Healy of University of California,
Berkeley, who led the team.
"This system is not a simple cell
culture where tissue is being bathed in a static bath of liquid," said
study lead author Anurag Mathur, a postdoctoral scholar in Healy's lab.
"We
designed this system so that it is dynamic. It replicates how tissue in
our bodies actually gets exposed to nutrients and drugs," Mathur
explained.
The study authors noted a high failure rate associated
with the use of nonhuman animal models to predict human reactions to
new drugs.
Much of the failure is due to fundamental differences in biology between species, the researchers explained.
"Using
a well-designed model of a human organ could significantly cut the cost
and time of bringing a new drug to market," Healy added.
The
heart cells were derived from human-induced pluripotent stem cells, the
adult stem cells that can be coaxed to become many different types of
tissue.
The researchers designed their cardiac microphysiological
system, or heart-on-a-chip, so that its 3D structure would be
comparable to the geometry and spacing of connective tissue fibre in a
human heart.
Within 24 hours after the heart cells were loaded
into the chamber, they began beating on their own at a normal
physiological rate of 55 to 80 beats per minute.
The researchers
put the system to the test by monitoring the reaction of the heart cells
to four well-known cardiovascular drugs.
The baseline beat rate
for the heart tissue consistently fell within 55 to 80 beats per minute,
a range considered normal for adult humans.
The researchers
noted that their heart-on-a-chip could be adapted to model human genetic
diseases or to screen for an individual's reaction to drugs.
The
engineered heart tissue remained viable and functional over multiple
weeks. Given that time, it could be used to test various drugs, Healy
said.
The findings were published in the journal Scientific Reports.