Heart disease is the leading cause of death in the US. By 2020, it is estimated the condition will be the leading cause of death worldwide. But could a new creation from scientists at Abertay University in the UK pave the way for a cure? The team has grown miniature beating human hearts in which they can induce heart disease, enabling them to test newly developed drugs.

This is not the first time a human heart has been grown in a lab. Earlier this year, Medical News Today revealed how a researcher from George Washington University in Washington, DC, created a mini heart that he said could improve treatment for people who have blood flow problems.

But according to Prof. Nikolai Zhelev, leader of this latest research at Abertay University, this is the first time it has been possible to coax disease in a lab-grown heart.

Specifically, Prof. Zhelev and his team have managed to induce ventricular hypertrophy in the mini hearts - a form of heart disease characterized by thickening of the heart muscles, which makes it more difficult for blood to be pumped around the body.

"In some people, a life-threatening abnormal heart rhythm will develop, and this is the most common cause of sudden death in young people," says Prof. Zhelev. "Although there are treatments, these only help to control the symptoms and there is no known cure at the moment."

But he and his team, who recently presented their research as the 5th World Congress on Biotechnology in Spain, hope their mini human hearts could lead to such a cure.

Cancer drug tested in mini hearts already showing promise

The team used stem cells to grow the hearts, which are only 1 mm in diameter and contract at approximately 30 beats per minute.

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This picture shows a hypertrophic heart cell within a mini heart. Molecules that are targets for drugs are highlighted in green.
Image credit: Abertay University.

Once grown, the scientists infuse the hearts with chemicals that cause abnormal growth of heart cells, known as cardiomyocytes. This causes the heart to become hypertrophic.

Biosensors are then used to pinpoint the molecules and their pathways involved in ventricular hypotrophy, allowing the team to develop drugs that target such molecules in the hope they will halt heart damage.

And Prof. Zhelev says one of the drugs they have tested - a compound that has recently completed phase 2 clinical trials in cancer patients - has already shown promise. The drug was able to stop hypertrophy in its tracks. Prof. Zhelev says:

"Although heart cells are the only ones in the body that will never get cancer, we noticed that the pathways the molecules in hypertrophic hearts follow are similar to those followed by molecules in cancerous cells, so we thought testing this new drug on these hearts might have the same positive effect. And this has certainly proved to be the case."

Prof. Zhelev admits that some of the drugs they have tested so far have produced negative effects, such as increasing the number of heartbeats per minute, making them stop altogether. But of course, the whole point of these mini hearts is to act as a model to seek out drugs that may be effective against heart disease, but without the side effects.

"We are still testing new drugs using this system to find new compounds with better efficiency and fewer side-effects," says Prof. Zhelev, adding:

"Once we know exactly which compounds work and which don't we'll begin developing new drugs which will then undergo further tests, before eventually being trialled in humans.

Although there is still a long way to go before the drugs become available commercially, we are extremely hopeful that we will one day be able to stop heart hypertrophy from developing in those at risk of the disease."

Prof. Zhelev talks more about the creation of the mini hearts in the video below:

Speeding up the drug search

Prof. Zhelev hopes to speed up the progress of this research by working with Prof. Jim Bown - a system biologist at Abertay University - to create computer models that can predict the behavior of cardiomyocytes, which will provide a better indication of how drugs will work in the mini hearts.

Prof. Bown explains that they have already developed interactive models and animations that show cancer cell growth, allowing them to see what happens when different drug doses and combinations are applied to the cells and how they impact cell growth.

"Because the signaling pathways in cancer cells and hypertrophic heart cells are so similar, we've been able to adapt this technology and apply it to cardiomyocytes," Prof. Bown says.

He explains that this will work by using initial data about cardiomyocyte growth, building models based on that data, and then informing Prof. Zhelev about what drugs to test next. "So we're carrying out a mix of experimental and theoretical biology here, using complex new technology to help us better understand the systems we're working with," Prof. Bown says, adding:

"Ultimately, the aim is to reduce the number of wet-lab experiments that Prof. Zhelev needs to do in order to find the drugs that are most likely to prevent heart hypertrophy from developing."

It is not only hearts that are being grown in the lab in an attempt to find new disease treatments and cures. Medical News Today recently reported how scientists at the University of Texas Medical Branch in Galveston successfully grew human lungs for the first time, while two studies recently published in The Lancet detailed the development of a lab-grown nostril and vagina.