A ‘heart attack on a chip’ device could lead to treatments for cardiovascular disease

“This enables us to more clearly understand how the heart is changing after a heart attack. From there, we and others can develop and test drugs that will be most effective for limiting the further degradation of heart tissue that can occur after a heart attack,” said Megan McCain, an associate professor of biomedical engineering and stem cell biology and regenerative medicine. She also developed the device with postdoctoral researcher Megan Rexius-Hall.

Heart disease is the leading cause of death in U.S.

Heart disease is the leading cause of death in America. This disease caused nearly 700,000 deaths in the U.S. in 2020. The most common type of heart disease is coronary artery disease, which can lead to a heart attack. About 18.2 million American adults have coronary artery disease. A heart attack occurs when fat, cholesterol or other deposits reduce the flow of blood and oxygen to the heart.

If a patient survives a heart attack, there’s a chance that the individual can still be fatigued, sick, and possibly die from future heart failure. The reasoning behind this is because heart cells don’t regenerate like other muscle cells. Scarring can also develop, which weakens the heart muscles.

Researchers don’t completely understand the process of how heart cells in the healthy and injured part of the heart transmit messages to each other, and how they change after a heart attack. McCain and Rexius-Hall are hopeful that their device will help to uncover some of the mysteries of what happens after a heart attack. “Fundamentally, we want to have a model that can lead to a better understanding of heart attack injury,” said Rexius-Hall. 

The microfluidic device

The heart attack on a chip, as it’s called, is a square microfluidic device a little larger than a quarter. A microfluidic device is a small-scale, clear tool that processes fluid through it. At the base, it’s 22-millimeter-by-22-millimeter and made from a rubber-like polymer called PDMS. It has two channels on opposite sides through which gases flow.

Above the base there’s a thin layer of the PDMS polymer, which is porous to allow oxygen through. On the top layer, there is a micro layer of protein.  The researchers created the device in a similar format mimicking the structure of the human heart. It is patterned in a way “so that the heart cells align and form the same architecture that we have in our hearts,” McCain stated. The final part of the tool includes rodent heart cells that are grown on top of the protein.

In order for the researchers to imitate a heart attack, gas with and without oxygen was released through each channel of the microfluidic device. This creates a similar likeness to a heart attack by “exposing our heart on a chip to an oxygen gradient, similar to what really happens in a heart attack,” McCain said.

Future use of the tool

Researchers can observe the practical differences that happen after a heart attack by viewing the microfluidic device under a microscope as it mimics a heart attack. This can help them look for changes such as arrythmia, in irregular heartbeat.

The device can allow researchers to watch changes to simulated heart tissue in real time, something that can’t be done with animal models. “It is very exciting and rewarding to envision our device having a positive impact on patient lives in the near future, especially for heart attacks, which are extremely prevalent,” McCain said.

In the future, the researchers want to make the model more detailed and intricate. They hope to add immune cells or cells that form scarring after a heart attack, called fibroblasts, to further analyze what happens during and after a heart attack.

The research team also hopes the small model will provide a testing opportunity and site for new heart drugs in the future.