Beating human hearts grown in a lab: Tiny organs are being infected with disease to test pioneering drugs
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Tiny human hearts that beat of their own accord are being grown by scientists at Abertay University in Scotland.
They have been developed specifically to find a cure for heart hypertrophy - a form of heart disease that can lead to sudden death.
Made from stem cells, the miniature hearts are just 0.04 inches (one millimetre) in diameter and contract at around 30 beats per minute.
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Tiny human hearts that beat of their own accord (pictured) are being grown by scientists at Abertay University in Scotland. They have been developed specifically to find a cure for heart hypertrophy - a form of heart disease that enlarges the organ and can lead to sudden death
Although healthy to begin with, the scientists are using chemicals to simulate the physiological conditions that will make them become hypertrophic - enlarged - due to abnormal growth of the cells that make up the heart.
THE END OF HEART DISEASE?
In April scientists discovered a way to block the formation of excess cholesterol that leads to heart disease.
Working with mice and rabbits, Johns Hopkins scientists successfully prevented the development of atherosclerosis, the main cause of heart attacks and strokes and the number-one cause of death among humans.
The condition develops when fat builds inside blood vessels over time and renders them stiff, narrowed and hardened, greatly reducing their ability to feed oxygen-rich blood to the heart muscle and the brain.
Once diseased, the hearts are then treated with newly developed medications to see if they can prevent the damage from occurring.
'Although human 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 doing too much strenuous exercise.
'The disease causes the heart muscle to thicken and stiffen, and makes it harder for the heart 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.
'Although there are treatments, these only help to control the symptoms, and there is no known cure at the moment.'
Made from stem cells, the miniature hearts are just 0.04 inches (one millimetre) in diameter and contract at around 30 beats per minute. Pictured here are miniature hearts 'in vitro', which means they are studied with cells of biological molecules outside their normal biological context
However, the miniature hearts being grown in Professor Zhelev's lab could help change that.
Using biosensors, Professor Zhelev was able to label specific molecules within the miniature hearts to see how the research should be led.
By establishing which molecules cause the hearts to become hypertrophic, he 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.
He added: 'We've tested a number of different compounds on these hearts - some of them entirely new ones that haven't been tested in humans yet, which is why we're testing them on these hearts we've grown in the lab.
'One of these compounds, however, is a drug that we have developed which has just completed phase-two clinical trials in cancer patients and has had very 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, said Professor Zhelev, this has proved to be the case.
Although healthy to begin with, the scientists are using chemicals to simulate the physiological conditions that will make hearts enlarged due to abnormal growth of the cells. Pictured here are cariomyocytes, muscle cells, in the tiny hearts
'Some of the compounds we've tested have had undesirable effects,' he continued, 'such as increasing the number of beats the hearts do per minute and making them stop beating.'
But he explained that other compounds, such as a new cancer drug in development, managed to protect the hearts and prevent them from becoming enlarged.
'We are still testing new drugs using this system to find new compounds with better efficiency and fewer side-effects,' he said.
'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.'
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