New patch helps hearts heal themselves after heart attacks

By Stephen Beech

A new high-tech "patch" will replace ones made from cow cells currently used to repair damage caused by a heart attack, say scientists.

The three-dimensional patch has been developed by Swiss scientists.

They explained that, following a heart attack, blood flow to the heart is interrupted - and the resulting lack of oxygen can cause damage to the vital organ.

The heart wall can rupture in severe cases, requiring immediate surgical intervention.

Currently, bovine pericardial patches, known as BPPs, are used to repair such heart defects owing to their stability, permeability, and ease of implantation.

But doctors say BPP has "significant" disadvantages.

Not only are they biologically "inert" - meaning they remain foreign bodies in the heart and cannot be broken down - but they can also cause unwanted reactions such as calcification, thrombosis, or inflammation.

Lead author of the new study, Lewis Jones, of ETH Zurich, said: “Traditional heart patches do not integrate into the heart tissue and remain permanently in the body.

Jones, who is completing his Ph.D. under the mentorship of Professor Robert Katzschmann, said the “RCPatch” - Reinforced Cardiac Patch - could become a long-term alternative to conventional patches made from bovine pericardium.

Study lead Katzschmann said: "Our goal was to develop a patch that not only closes a defect but also helps to repair it completely."

The research team says the new RCPatch has "significant" advantages over bovine pericardium because it consists of three parts: a fine mesh that seals the damage, a 3D-printed scaffold for stability and a hydrogel populated with heart muscle cells.

The scaffold has a lattice structure composed of a degradable polymer, which the researchers produce in a 3D printer.

Jones said: “The scaffold is stable enough and can be filled with a hydrogel containing living cells."

The ETH researchers combined the lattice structure with a thin mesh so that it could be easily attached to the heart.

Katzschmann and his team enriched this mesh with the same hydrogel.

That allows the RCPatch to integrate into the surrounding tissue and grow together with the heart muscle cells, according to the study published in the journal Advanced Materials.

Jones said: “The big advantage is that the scaffold is completely degraded after the cells have combined with the tissue.

"This means that no foreign body remains."

He says the combination of the three components results in a dense, easy-to-use heart patch that is partly made of living cells.

An initial animal experiment showed the ability of the patch to be successfully implanted and withstand the high pressure in the heart.

The researchers succeeded in preventing bleeding and restoring cardiac function.

In preclinical tests on pig models, the RCPatch was used to close an artificial defect in the left ventricle.

Katzschmann added: “We were able to show that the patch retains its structural integrity even under real blood pressure."

He said the research group has created a "promising" foundation for the development of a mechanically reinforced and tissue-engineered heart patch suitable for implantation in humans.

In the long term, the RCPatch is intended not only to repair but also to regenerate myocardial damage, ultimately healing the heart.

Now the research team aims to develop the material further and investigate its stability in long-term animal studies.