‘Velcro’ patch to help heart attack victims

AVELCRO- LI KE patch could repair the damage caused by a heart attack. The experimental patch has been designed to replace heart muscle killed off during an attack.

It is made from layers of man-made mesh which — just like Velcro — stick together with tiny hooks and loops. Each mesh layer is coated with new heart cells that will eventually grow into fully-formed, working heart tissue.

During a heart attack, the supply of oxygen-rich blood to the organ is cut off, usually by a blocked artery, and when this occurs some of the heart’s muscle is permanently damaged. This can stop the heart from pumping properly, known as heart failure, which leads to such symptoms as severe tiredness, shortness of breath and chest pain.

Around 65,000 people a year in the UK develop heart failure as a result of a heart attack.

Although there are drugs that can control the symptoms of heart failure, many people do not respond to these because the damage to the heart is too great.

There has been mounting interest in the development of cardiac ‘patches’ that are implanted after a heart attack to restore some heart function and also to prevent longterm, life-threatening damage.

A major challenge is developing patches thick enough to match existing heart tissue (between 8mm and 10mm) while still being flexible enough to contract in the same way as ordinary heart muscle. The patch created by a team from the University of Toronto gets round this problem because it is made from multiple layers of an incredibly thin, flexible substance, which lock together.

Each layer has hundreds of tiny hooks on one side and loops on the other, just like Velcro.

The rubbery material, known as POMAC, was engineered specifically for medical use. The sheets used in the patch have a honeycomb structure which allows the heart cells that line each layer of the patch to link up to form new tissue. The patch is ‘biocompatible’ which means it won’t be attacked by the body’s immune system and will gradually break down over a period of months, exiting the body with other waste.

For their recent study, published in the journal Science Advances, the Toronto team coated each mesh strip with heart stem cells taken

from rats. Each layer was then snapped together to form a patch with a similar thickness to normal heart muscle. A mild electric current was applied to the cells to encourage them to grow, and after a few days, they had grown enough to start beating, as normal heart cells do. As the cells moved, the patch matched the normal contraction and expansion of the heart’s healthy tissue.

The patch is likely to be tested in humans in the next couple of years. For human patches, heart cells are likely to be made in the lab using stem cells taken from THE the patient’s skin.

advantage of the patch over, say, just injecting new heart cells directly on to the area, is it gives better control as to where the cells end up and the mesh secures them in one place.

Dr Klaus Witte, a consultant cardiologist with the Leeds Teaching hospitals NHS Trust, said of the research: ‘ This is very exciting. Researchers have been looking for years at ways of delivering live cells into the heart. The problem has always been that these new cells tend not to survive on their own.’

But with the patch, he said, heart muscle cells have a better chance of survival.

MEANWHILE, a pill for bladder problems could also be used to treat heart failure. In a trial at Oxford University and other centres across Europe, 300 patients with heart failure are being given mirabegron, which treats an overactive bladder by relaxing the muscles, so patients do not feel a constant need to go to the loo.

Researchers believe it could also slow down or prevent the stiffening of the heart muscle that sometimes causes heart failure.