Citizens for
Alternatives to Animal Research and Experimentation(CAARE)
August 2015
One of the great challenges of drug discovery is discerning whether, and to what extent, a drug is safe for human use. Increasingly, pharmaceutical companies and scientists are acknowledging that up to 95% of drugs fail to be deemed safe for people due to misleading test results from animal studies.
Consequently we are seeing a growing interest in the development of
“organ chips,” novel platforms for growing human cells and tissues in an
enhanced micro-environment that creates a simulated organ suitable for
testing drugs. In the world of drug development, the liver chip is moving to
the forefront of this line of research, owing to the liver’s vital role in
filtering potentially toxic compounds from the blood.
As research on organ chips moves forward, their ability to surpass animal
research and elucidate cell-drug interactions with cutting-edge clarity is
being demonstrated.
In August, scientists at the Hebrew University of Jerusalem and the
Fraunhofer Institute for Cell Therapy and Immunology in Germany used their
liver-on-a-chip to uncover new information about the popular drug
acetaminophen (Tylenol), demonstrating a toxic pathway that was previously
unknown.
Liver-on-chip device and microscopic image of bionic liver
Photo credit: Yaakov Nahmias / Hebrew University
The Israeli-German research was unique because the scientists incorporated
nanotechnology-based optoelectronic sensors into the liver chips. As the
study’s lead author, Dr. Yaakov Nahmias of Hebrew University explains, “We
realized that because we are building the organs ourselves, we are not
limited to biology, and could introduce electronic and optical sensors to
the tissue itself. Essentially we are building bionic organs on a chip.”
The addition of the nanosensors was the key to revealing the mechanism of
acetaminophen toxicity, conferring a much greater level of accuracy by
allowing the scientists to analyze the data in real time. “We showed that
acetaminophen caused direct damage to cellular metabolism … ,” said Dr.
Nahmias. “Our discovery explains why acetaminophen sometimes damages kidney
and skin. It was not possible to get this type of information from animal
experiments."
Close-up liver-on-chip device.
Credit: Yaakov Nahmias / Hebrew University
Only in the past year have liver chips begun to be used in actual
practice, and so far they have been embraced by a small handful of
pharmaceutical manufacturers.
But we’re already seeing their potential to go beyond the limitations of
animal research and deliver results that are innovative and, more
importantly, human specific. In August 2014, the US biotech firm Organovo
demonstrated that its liver model was able to predict liver toxicity where
animal tests had failed.
The latest Israeli-German study using the enhanced bionic liver chip
provides yet another example of the ability of organs-on-chips to surpass
animal experiments.
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