Actual guinea pigs are still going to be with us, though
A research team from the Wyss Institute at Harvard University has successfully built a 3D printed “heart-on-a-chip,” which mimics the function of the actual cardiac organ. Harvard had previously developed lungs-on-a-chip and intestines-on-a-chip that imitate human functions, and the heart simulator, described in the Nature Materials journal, is the most advanced device yet to come out of Harvard.
The heart tests confirmed the viability of using it to study the effects of various inputs on the organ, as if it were a real heart suffering from stress or sickness. A licensed startup, Emulate, is already exploring applications for developing the “human emulation” technology to be used by other scientific, academic, governmental, and corporate entities.
Such organ simulators even have the potential to replace animal testing in institutional and company labs.
Though man-made replacement organs are still a long way off, these devices have immediate applications with “in vitro tissue engineering, toxicology and drug screening research,” according to the researchers. Other products from the institute can do this as well. The lungs that debuted several years ago were able to simulate being attacked by a disease. And the intestines, complete in 2015, were specifically developed for exploring treatment options for inflammation, since it replicates the mechanical and chemical functions of our inner workings.
With the ability to simulate our body parts and introduce diseases, medicines, and other substances to actual human cells that can be monitored in real-time, there would be little need to test drugs or contagions on animals whose systems only superficially resemble ours (like mice) and must perish in droves over years, sometimes decades, to yield researchers even a few usable results. Having human cells to work with from the start would probably reduce the trial time and failure rate of existing test methods. Mice and rats remain the animals of choice as it is possible to modify their genes for specific tests, and of course, myriad cultures in petri dishes. But success with this organic material rarely leads to success considering the sheer number of trials that never get past the first phases.
Yet there remain many issues to overcome. While multiple technologies, such as computer modeling – in silico testing – and stem cells, do exist that could replace animal testing, both these and organs-on-a-chip are still extremely expensive to develop and build, since they are constructed in clean rooms with microscopic precision. It is also not yet possible to “print” a whole human body (or the most complex organ of all, the brain), but some of these organs-on-a-chip can be linked together to better simulate a functional internal system inside a human, being keyed in to imagine as if there were a set of lungs beating alongside the heart.
Medical and cosmetics applications still rely heavily on animal testing. Impact tests using dummies have largely replaced the use of animals to measure trauma from accidents in vehicles, but many military applications use animals for ballistics, surgical, and WMD research. Without live animals in place of human subjects, or high-fidelity medical simulators to mimic living beings, much less research can be done, advocates of such testing counter. Critics counter that if better simulators were available, they would be more versatile and closer to the real deal – and that much of what can be learned comes from reviewing accidents and emergency situations actual people find themselves in anyway.
In the future, Wyss hopes to further develop the technology for actual therapeutic or replacement purposes. The institute’s spleen-on-a-chip, for instance, was developed not just as a medical simulator or test bed for drug trials, but as a blood cleaning tool to combat sepsis.
It has already been successfully tested on infected human blood, and, of course, animals.