Could a Liver in a Test Tube Mean the End of Animal Drug Testing?

Animal-rights advocates and medical researchers have reason to be excited about an innovative new drug-testing technology. A new device that imitates the metabolic processes in animal livers is bringing scientists closer to eliminating animal testing altogether.

Of the more than 10,000 presentations held at the 247th National Meeting & Exposition of the American Chemical Society this week, one of the most promising was research into chemosynthetic livers that mimic metabolic processes of real animals. The test-tube livers are a cruelty-free alternative to traditional drug testing that could pave the way for pharmaceutical, cosmetic, and other areas of research that have long depended on the use of rats, rabbits, and other small animals.

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How Does It Work?

When testing for drug interactions and toxicity, scientists typically rely on analyses of animals—such as rodents, dogs, and monkeys—through a process called metabolic profiling. After the drugs have been metabolized by the animals' bodies, researchers examine the molecular byproducts (metabolites) in the animals’ bodily fluids to identify possible side effects of the drugs being studied. This process must occur before tests in human subjects can take place.

The new Biomimiks technology from Empiriko Corp. takes animals out of the picture with catalysts that act like a group of enzymes called cytochrome P450, many of which break down drugs in the liver.

“In many cases, toxic metabolites counteract the beneficial effects of drugs, causing harmful side effects,” said Mukund Chorghade, Ph.D., chief scientific officer of Empiriko Corp. and president of THINQ Pharma. “Since a majority of drug metabolites are implicated in adverse reactions, metabolites hold the key to understanding many critical pharmacological processes.”

The use of chemosynthetic livers not only eliminates animals from the process but could also expedite drug testing. As Chorghade explained at an exposition news briefing, synthetic chemists typically must synthesize many compounds to inject into animals, and then analyze their bodily fluids to determine the number of metabolites and isolate them in small quantities.

“Biomimiks’ saddle-shaped catalysts are incredibly stable and fast-reacting," said Chorghade. "And they generate the large volumes of metabolites needed for further research.”

Better Than Animal Subjects?

At the news briefing, Chorghade said he holds the “brash opinion” that Biomimiks are superior to live animal testing for several reasons. Animal testing is lengthy and expensive. It also takes the sacrifice of many animals to identify the side effects of certain drugs—a process that can be time intensive and not entirely indicative of the chemical reactions that would occur in humans.

“Animal models are based on a variety of animal species, which produce different metabolic pathways and don’t necessarily correlate with human pharmacology, leading to variations in efficacy and toxicity of drugs,” Chorghade said. “It is difficult to extrapolate [from animals to humans] the maximum tolerated drug dosing and minimum observed biological effects.”

While animal-rights advocates are sure to applaud the efforts of Chorghade and the developers of Biomimiks to reduce the use of animals for drug research, the complete eradication of animal testing isn’t in sight just yet.

From a logistical standpoint, the researchers will need to test 100 drugs with the Biomimiks technology as required by the U.S. Food and Drug Administration for regulatory approval. So far, they have tested around 50 drug compounds. Chorghade noted 2010 regulations by the European Union to restrict animal testing, but he said that animal tests are still crucial for some pharmaceutical discovery and development.