One of the things that makes heart disease so problematic is the fact that after a heart attack occurs, the scar tissue that replaces the damaged heart tissue isn’t capable of expanding and contracting – it doesn’t “beat,” in other words. This leaves the heart permanently weakened. Now, however, scientists from Harvard-affiliated Brigham and Women's Hospital (BWH) have developed artificial heart tissue that may ultimately provide a solution to that problem.

At the base of the material is a rubbery gel known as MeTro. It’s made from tropoelastin, which is the protein that gives human tissues their elasticity.

A team working in the lab of Dr. Ali Khademhosseini made sheets of the material by taking some of the gel in its liquid state, and pressing it between a glass slide and a flat mold with a micro-patterned surface. Ultraviolet light was applied to help the gel set. Once it solidified, one side of the gel took on the pattern of the mold. The BWH scientists experimented with a variety of patterns, all of which were designed to make the material highly elastic, while retaining sufficient mechanical strength for use on the heart.

The resulting sheets of MeTro gel were then seeded with heart muscle cells, providing a structure in which those cells could function, reproduce, and communicate with one another.

It is hoped that future generations of the material could be used to patch over damaged areas of the heart, the recipient's cells in the material gradually merging with the cells in the surrounding tissue, until the MeTro is completely replaced with functioning heart tissue. Before that can happen, however, the scientists need to create three-dimensional versions of the material, that contain vascular networks to supply nutrients to the cells. They plan on doing so by combining multiple layers of the cell-seeded gel.

Another challenge will lie in finding a way of harvesting enough of the patient's heart muscle cells – or growing them from stem cells – to sufficiently seed the gel.

This is far from the first attempt at creating such “heart patches." Institutions such as UC San Diego, MIT, the Max Planck Institute, the University of Washington, Brown University and Duke University have all developed materials. According to BWH’s Dr. Nasim Annabi, however, MeTro offers superior functionality and strength.

A paper on the research was published last week in the journal Advanced Functional Materials.

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