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A team of bioengineers has announced it's one step closer to creating a four-organ human replica for experimentation.

Much of the work currently being done to engineer human organs through 3D printing and various other techniques is not carried out with the aim of delivering a fully-fledged implantable transplant candidate. Of course that's the ultimate aim, but for now these tiny replicas -- sometimes only half a millimetre in size for the sake of cost -- are being developed to test drugs.


We have picked a scale that is between microhuman and millihuman Rashi Iyer, Los Alamos National Laboratory

A multi-institutional team is attempting to engineer a connected human liver, heart, lung and kidney for this purpose through a five-year $19 million (£11 million) project known as Advanced Tissue-engineered Human Ectypal Network Analyser (Athena -- there's a backronym if ever we heard one). And it's just engineered a 3D human liver that will respond to toxic chemicals in the same way the real thing might, according to a press release published at esciencenews.com. The drug tested was acetaminophen, commonly found in painkillers and harmful to the liver in high doses.

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"The original impetus for this research comes from the problems we are having in developing new drugs," said John Wikswo, director of the Vanderbilt Institute for Integrative Biosystems Research and Education, who made the announcement at the Society of Toxicology meeting in Phoenix this week. "A number of promising new drugs that looked good in conventional cell culture and animal trials have failed when they were tested in humans, many due to toxic effects.

That represents more than $1 billion in effort down the drain." The hope is, that rather than testing "first in line" cells, testing on a functioning organ replica will deliver more accurate results.

This has the potential for huge cost savings, but could of course potentially get the right drugs, to the right people, much faster.

The project is a huge feat, with experts in the different organs called in from institutes in Berlin, California and Harvard, a team developing hardware to test it and another engineering the blood surrogate that will sustain the tiny organs. It was the Berlin team, based at Charité Universitätsmedizin, which has now engineered the four-layer, 3D liver measuring one tenth of a millilitre. "We have picked a scale that is between microhuman and millihuman," commented Rashi Iyer of the Los Alamos National Laboratory, who is coordinating Athena. "I think the success that we are having with our liver device means that we have hit the sweet spot."


Vital to keeping costs down, the team managed to create a mini perfusion system to sustain the organ, costing 40 times less that the original system, as well as an ion mobility-mass spectrometer that is used to track cell activity at a molecular level as they react to the drugs -- in this case, the acetaminophen.

Wikswo did not say how long the cells could be sustained for in experiments, but the hope is it will be able to reach one month eventually. A liver replicated by a team at US biotechnology firm Organovo, by comparison, managed to keep its 3D replica alive for

just five days, but still had plans to sell the tissue this year following further development.