Researchers grow heart tissue on spinach leaves

Through a series of experiments, a team of researchers have grown beating human heart cells on spinach leaves.

Current bioengineering techniques, like 3-D printing, can't build the intricate, branching network of blood vessels that makes up the heart tissue. However, a team of researchers from the Worcester Polytechnic Institute (WPI), University of Wisconsin-Madison and Arkansas Sate University-Jonesboro have successfully turned to plants.  

According to the authors of the report -- which will be published online the journal, Biomaterials, in May -- details how plants and animals use very different approaches to transporting fluids, chemicals and other materials. However, due to similarities in vascular network structure, the authors were able to develop this technology which "opens the potential for a new branch of science" that investigates those very similarities even further.

The team grew beating heart tissue on spinach leaves that were stripped of plant cells in a process called decellularization. Researchers used a detergent, which is a water-based cleansing solution that binds with dirt and other impurities to wash the cells away.

When the plant cells were gone, researchers were left with a framework made primarily of cellulose, the main chemical that forms the structure of plants. Cellulose has also been used in cartilage and bone engineering, as well as wound healing.

In the experiments, the researchers were able to line the veins of spinach leaves with the same cells that line a human's blood vessels. Following that, they were able to send fluids and tiny microbeads about the same size as human blood cells through the revamped veining. 

The authors say that these kinds of "proof-of-concept" studies open the door to using multiple spinach leaves to grow layers of healthy heart muscle to treat heart attack patients. 

Other plants stripped of cells could provide the framework for a wide range of tissue engineering technologies.

"We have a lot more work to do, but so far this is very promising," said Glenn Gaudette, PhD, professor of biomedical engineering at WPI and corresponding author of the paper.

"We weren't sure it would work, but it turned out to be pretty easy and replicable. It's working in many other plants," said the paper's first author, Joshua Gerslak, a graduate student in Gaudette's lab. Gerslak helped design and conduct the experiments, and developed the process of decellularization.

The team was also able to successfully remove cells from parsley, sweet wormwood and peanut hairy roots. They expect that the technique will work with a variety of plant species and could even be adapted for specialized tissue building studies.