Laboratory grows dozens of beating 1-mm hearts

London: Miniature human hearts that beat of their own accord have been grown in a laboratory using stem cells, in an attempt to find a cure for a disease which can lead to sudden death.

The hearts are just 1 mm in diameter and contract at around 30 beats per minute, according to researchers at Abertay University in the UK. They have been developed to find a cure for heart hypertrophy — a form of heart disease that can lead to death.

Although healthy to begin with, the scientists use chemicals to simulate the physiological conditions that will make the hearts hypertrophic — enlarged — due to abnormal growth of the cells that make up the heart (cardiomyocytes).

Once diseased, the hearts are treated with new medication to see if they can prevent the damage from occurring.

“Although hearts have been grown in labs before, this is the first time it has ever been possible to induce disease in them,” said Professor Nikolai Zhelev, who is leading the research. “Heart hypertrophy can be hereditary, can be caused by diseases such as diabetes, or can be caused by too much strenuous exercise.”

The disease causes the heart muscle to thicken and stiffen, and makes it harder to pump blood 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,” he said. Prof. Zhelev believes the miniature hearts could help change that.

The team has been able to label molecules within the hearts to see where they are going. By establishing which molecules turn the heart hypertrophic, Prof. Zhelev has been able to target drugs at these molecules and prevent them from going down the path they would usually take, and prevent them from becoming hypertrophic.