Thousands of miniature human hearts have been grown by scientists to explore a possible cure for a form of heart disease.

The mini organs, which beat of their own accord, have been developed specifically to look at heart hypertrophy – where the heart muscle thickens, making it harder to pump blood around the body.

Researchers at Abertay University in Dundee are using the tiny hearts to test potential drugs they hope could eventually allow them to stop it developing in those at risk of the disease.

Made from stem cells, the tiny hearts are just 1mm in diameter and contract at about 30 beats per minute.

Although healthy to begin with, scientists are using chemicals to make them become hypertrophic, or enlarged, due to abnormal growth of the cells that make up the heart.

Once diseased, they are then treated with newly-developed medications to see if they can prevent the damage from occurring.

The team said that human hearts had been grown in labs before but this was the first time it had been possible to induce disease in them.

“Heart hypertrophy can be hereditary, can be caused by diseases such as diabetes or can be caused by doing too much strenuous exercise,” said lead researcher Professor Nikolai Zhelev.

“In some people, a life-threatening abnormal heart rhythm will develop and this is the most common cause of sudden death in young people.

“Although there are treatments, these only help to control the symptoms and there is no known cure at the moment.”

The process works by using biosensors to label specific molecules within the tiny hearts to see where they are going.

By finding out which molecules cause the hearts to become enlarged, the team have been able to target the drugs at these molecules and stop them going down the path they would usually take – preventing them from becoming hypertrophic.

Zhelev, who will present the research at a conference in Spain on Thursday, said a number of different drugs were being tested – some for the first time.

He said one drug, which is being trialled in cancer treatment, had had positive results.

“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,” he said.

“Some of the compounds we’ve tested have had undesirable effects – such as increasing the number of beats the hearts do per minute and making them stop beating – but others, such as the new cancer drug that is in development, have managed to protect the hearts and prevent them from becoming hypertrophic.”

He said the tests were ongoing but the team was “extremely hopeful” they could be able to stop heart hypertrophy developing in those at risk of the disease.