Scientists invent muscles from the spray can

Step to the artificial heart: muscles from the spray can

About one to two percent of the adult population in the developed world suffers from severe heart failure (heart failure). If possible, a donor heart is transplanted to end-stage patients. Often, however, no suitable organ is available. An artificial heart could be the salvation. In order to recreate the complex organ in the laboratory, however, it would first be necessary to cultivate complex, living tissue. Researchers have now come closer to this goal: They used a spray process to produce functioning muscle fibers.

One of the most common diseases causing death

Cardiac insufficiency (heart failure) is one of the most common fatal diseases. As a result of this disease, the heart is no longer able to provide the body with sufficient blood and oxygen. Over the past few years, new approaches to treat heart failure have been reported time and again that can increase resilience and performance. But as the heart weakens and threatens to fail, a heart transplant is the only treatment that can save the lives of the critically ill patient. However, not always a suitable organ is available. An artificial heart could be the salvation. Swiss researchers from the Federal Materials Testing and Research Institute (Empa) have come a little closer to this goal.

Anyone who relies on a transplant because of heart failure must hope for a suitable donor organ. Ideal would be an artificial heart. Researchers have come one step closer to this. They used a spraying process to develop muscle fibers. (Image: psdesign1 / fotolia.com)

Artificial organ in heart failure

Those who rely on a transplant because of heart failure must hope for a suitable donor organ. An elegant alternative would be an artificial heart, which does not trigger any rejection reactions in the body after implantation.

The project "Zurich Heart" of the research association University Medicine Zurich, of which Empa is a partner, is currently developing such an artificial heart.

So that the pump from the laboratory is accepted by the body, it should - wrapped in human tissue and be lined - like a cloak of invisibility.

However, growing multi-layered functional tissues is still a major challenge in the emerging field of tissue engineering..

Empa researchers have now succeeded in growing cells in a three-dimensional plastic framework into muscle fibers.

Muscle fibers provide stability and flexibility of the steadily beating heart

"The human heart is naturally composed of several layers of different tissues," explains Lukas Weidenbacher of the Empa department Biomimetic Membranes and Textiles in St. Gallen in a statement.

Muscle fibers in the lining play a crucial role here, because they provide stability and flexibility of the constantly beating heart.

Growing multi-layered muscle fibers, however, is difficult because the cells must first be placed in a spatial framework.

"Although it is possible to produce three-dimensional plastic structures that are very similar to human tissue, such as so-called electrospinning," said Weidenbacher.

Here, liquid polymers are spun as gossamer threads in the form of natural tissue. Harmful solvents that are necessary for the method, however, are poison for the sensitive cells.

Slimy protection

The Empa researchers have therefore packed the precious cells in protective capsules. A gelatine shell contains one to two cells each. This protects the cells from the solvents.

A special spraying technique, electrospraying, allows the capsules to be inserted into the pores of the spun scaffold. "The spraying can survive the cells protected in this way very well," explains the material scientist.

Once the cells have settled at the target site, the gelatine capsule dissolves within minutes.

With the Scanning Electron Microscope, images of the cells in their plastic nest show that once the capsules are dissolved, the immature progenitor cells begin to fuse together and mature into elongated muscle fibers.

At the end, a structure should be created that is as similar as possible to natural muscle tissue. "Since the artificial heart is permanently flushed by the bloodstream, it is important that the surfaces are designed so that no clots form," says Weidenbacher.

Invisible to the body

For the series of experiments, the researchers used immature muscle cells from a mouse cell line. The progenitor cells differentiated into the scaffold and produced proteins that are typically found in muscle.

However, the implantable artificial heart will in future be equipped with cells that originate from the patient himself. Thus, a personal heart could be bred for those affected, which remains "invisible" for the body's defense. (Ad)