Researchers have shown that heart "patches" grown in the lab are now safe and ready for human trials for people who have had their hearts damaged by a heart attack.
These patches could one day cure debilitating heart failure, which affects an estimated 920,000 people in the UK and is on the rise as more and more people survive heart attacks.
Researchers led by Professor Sian Harding at Imperial College London have developed a way to grow thumb-size patches of heart tissue (3 centimeters x 2 centimeters) that contain up to 50 million human stem cells. The stem cells are programmed to turn into working heart muscle that can be seen "beating". One or more of these patches could be implanted on to the heart of someone after they've had a heart attack to limit, and even reverse, the loss of the heart's pumping ability.
During a heart attack, the heart is starved of vital nutrients and oxygen, killing off parts of the heart muscle. This weakens the heart and can eventually lead to heart failure, a debilitating condition that makes even every day simple tasks, like climbing the stairs or getting dressed, exhausting.
In this latest study, these patches have been shown to be safe in rabbits and to lead to an improvement in the function of the heart after a heart attack. After a period of up to 4 weeks, detailed heart scans showed that the hearts' left ventricle (the chamber responsible for pumping blood out to the body through the aorta) was recovering without developing any abnormal heart rhythms – a potential side effect of other stem cell delivery methods. Importantly, the patches appeared to be nourished by blood vessels growing into them from the recipient heart.
Once sewn in place, the patches are intended to physically support the damaged heart muscle and help it pump more efficiently, while also releasing natural chemicals that stimulate the heart cells to repair and regenerate. Eventually, the patches would hopefully be incorporated into the damaged heart muscle and repair it.
This technology creates patches that start to beat spontaneously after three days and start to mimic mature heart tissue within one month. They can then be implanted into damaged hearts to help repair the muscle and recover the heart's vital pumping function.