A laboratory-grown heart 'patch' that beats could undergo human clinical trials within 4 years in people with hearts damaged after a heart attack, scientists said.
Researchers at Imperial College London have developed a way to grow thumb-sized patches of heart tissue that contain up to 50 million human stem cells.
The hope is that after being grafted on to the recipient's heart, the patch, grown from a patient's own cells, would be programmed to turn into working heart muscle.
Photo credit: Imperial College London/British Heart Foundation
One or more of these patches could be implanted onto the heart of someone following a heart attack to limit, or even reverse, the loss of the heart's pumping ability, the researchers said.
The lack of efficacy of stem cell therapy for the treatment of heart failure may be caused by the cells being 'washed away' within a few hours when existing intra-coronary or intramyocardial delivery methods are used, according to Dr Richard Jabbour, who carried out the research at the London British Heart Foundation Centre of Regenerative Medicine.
He told Medscape News UK: "By combining the cells into a matrix and forming a patch, we've shown that the cells are retained in the host a lot longer than other delivery methods, therefore improving the function and prolonging the improvement of function."
Upscaling for Human Clinical Trials
The research, presented at the British Cardiovascular Society (BCS) Conference in Manchester, showed how initially small patches could be grown to a clinically relevant size and matured in-vitro.
Once matured, the patches underwent preclinical testing in a rabbit model of myocardial infarction.
Dr Jabbour said that a few years ago "the patches that were being made were tiny – 10mm by 1mm. Now, the patches really have been upscaled by a factor of 20 in the space of a couple of years. The field is moving on very rapidly."
The patches, measuring 3cm×2cm×1.5mm were sewn in place 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.
The patches began to beat spontaneously within 3 days of fabrication and after 28 days of dynamic culture showed the development of several mature characteristics when compared with early patches. Preliminary experiments indicated that the patch improved left ventricular function when grafted onto infarcted hearts.
Scans also revealed that the grafts were well vascularised and that the vasculature was not human in origin, suggesting that the vessels were originating from the host.
Next Steps
The next step would be to use these results to design clinical trials in humans, said Dr Jabbour, who predicted the start of phase I clinical trials in "anywhere between 2 to 4 years".
Prof Metin Avkiran, associate medical director at the British Heart Foundation, which funded this research, said: "This is a prime example of world-leading research that has the potential to mend broken hearts and transform lives around the globe.
"If clinical trials can show the benefits of these heart patches in people after a heart attack, it would be a great leap forward for regenerative medicine."
Development and preclinical testing of a large heart muscle patch, Jabbour R et al, abstract presented at the British Cardiovascular Society (BCS) Conference. Abstract.
