University of Toronto Engineering researchers have created a device that could basically be described as a gym for lab-grown cardiac tissue. The new development uses a rigorous training regimen to grow heart cells that are more lifelike than ever.
A gym in a petri dish
It can also measure how strongly they beat in order to test the effects of potential drug molecules. "Many potential new drugs fail because of toxicity issues, and cardiac toxicity is a major challenge," says Professor Milica Radisic, who led the research team.
"You can test potential drugs on heart cells grown in a petri dish, but those cells don't look the same as the cells in a real heart, and you can't get much information about their actual cardiac function."
The new device has the crucial advantage of enabling lab-grown cells and tissues to develop into forms that more closely mimic those actually present in the human body. The new platform, called Biowire II, consists of two elastic polymer wires positioned three millimeters apart.
The heart cells are placed in a small band of tissue between the wires. This is how researchers also succeed in measuring the cells' strength or force of contraction.
When the cells contract, they bend the wires enabling scientists to measure the amount of deflection to deduce the force of contraction.
"The advantage of this system is that it tells us how a given drug molecule is affecting the cardiac output by examining forces of contraction and other key functional readouts," says Yimu Zhao, a Ph.D. candidate in Radisic's lab and the lead author on the paper.
"Does it weaken the heart or make it stronger? It will help find new drugs to treat heart conditions, but also eliminate drugs for other conditions that have adverse effects on the heart."
Furthermore, the device features electrical pulses to simulate exercise, training the heart cells as if they were in a tiny gym. The result is more lifelike tissue.
"We have created both atrial and ventricular heart tissues, and we can even grow a heteropolar tissue, one with both atrial and ventricular ends," says Zhao. "Some drugs have a selective action on one or the other. With this system, we can detect this more efficiently."
The applications of this gym in a petri dish are in improving both the efficiency and the number of tests that drug researchers can conduct.
"If our lab-grown tissues can keep dangerous drugs out of the pipeline and help find new drugs to treat heart conditions, it will save thousands of lives," says Radisic.
But even more promising is the possibility to one day have lab-grown tissues so effective at mimicking real ones they can then be implanted back into humans to repair damaged organs. Radisic and her team are also working on separate technologies to hopefully see this option become reality.
Their paper is published in the journal Cell.