14 DAY TRIAL // A report published in yesterday's issue of the journal Scientific Reports details the use of human stem cells to grow miniature hearts housed in silicone devices in laboratory conditions.
The experiments, carried out by researchers with the University of California, Berkeley in the US, are expected to eliminate the need to test new drugs targeting the cardiovascular system on animals.
The science of growing hearts in the lab
Writing in the journal Scientific Reports, the University of California, Berkeley specialists detail that, as part of their work, they started by exposing human stem cells to carefully selected chemical cues that compelled them to develop into heart cells.
The cells were then placed inside silicone devices measuring about 1 inch (2.5 centimeters). The shape of these devices helped keep the cells aligned and coaxed them to develop in multiple layers forming a three-dimensional structure.
The scientists say that the so-called hearts-on-chips that they developed behaved like real organs do, meaning that they responded to stimuli, i.e. heart medication, and even had narrow channels similar to blood vessels delivering nutrients to them.
It is said that the laboratory-grown heart cells started beating at a rate of about 55 to 80 beats per minute about 24 hours after having been placed in the silicone devices and remained viable for several weeks. During this time, they responded to drugs like actual organs do.
“This system is not a simple cell culture where tissue is being bathed in a static bath of liquid. We designed this system so that it is dynamic; it replicates how tissue in our bodies actually gets exposed to nutrients and drugs,” said researcher Anurag Mathur.
Why give up on animal testing?
For starters, there are many who argue that testing new drugs on animals is unethical. What's more, the University of California, Berkeley researchers behind this investigation argue that animal models are not a reliable indicator of how human patients will respond to a certain heart drug.
This is because the cardiovascular system is unique to each species. Otherwise put, what works on dogs or guinea pigs might not work on people. Hence, it would be great if medical experts could test drugs on human organs without endangering a patient's life in the process.
The University of California, Berkeley scientists argue that, given how similar they are to the real deal, their laboratory-made hearts-on-chips could easily replace animals in experiments meant to determine the efficacy of newly developed drugs.
If grown from a patient's own stem cells, the artificial miniature hearts could even indicate how certain chemical compounds will affect one individual or another. This would transform medicine and healthcare forever, the scientists explain.
