Pursuing a viable way to regenerate human organs and tissues, scientists have turned to an unlikely source — the salad bar.
Researchers from Worcester Polytechnic Institute successfully grew beating heart cells on spinach leaves in a technique that, while in preliminary stages, holds vast potential for regenerating tissue, organs and even bones to use for implantation in people suffering from disease.
The key to the new research rests on the methods by which plants, such as spinach, transport fluids and other substances. Their vascular networks help solve a problem that other bioengineering tests have encountered — namely, how to establish a network of blood vessels that can carry oxygen, nutrients and other molecules deep into the tissue of an organ.
The plant-based process hinges on a concept known as decellularization, which “removes cellular material from a tissue or organ,” leaving just a “scaffold” that can be used for other purposes.
“I had done decellularization work on human hearts before,” said first author Joshua Gershlak, “and when I looked at the spinach leaf its stem reminded me of an aorta. So I thought, let’s perfuse right through the stem. We weren’t sure it would work, but it turned out to be pretty easy and replicable. It’s working in many other plants.”
The researchers stripped away plant cells from the spinach leaves and “cultured” heart cells on them. They also successfully transported fluids and molecules that were similar in size to human blood cells through the vascular network of the spinach leaves, suggesting that the leaves may serve as a way to grow healthy heart muscle.
“We have a lot more work to do, but so far this is very promising,” said Dr. Glenn Gaudette, professor of Biomedical Engineering at Worcester Polytechnic Institute and corresponding author of the paper. “Adapting abundant plants that farmers have been cultivating for thousands of years for use in tissue engineering could solve a host of problems limiting the field.”
Tapping Into a Plant’s Cellular Networks
The framework that the researchers discovered is left behind in the decellularization process may open up a whole new focus of study, they say.
“Plants and animals exploit fundamentally different approaches to transporting fluids, chemicals, and macromolecules, yet there are surprising similarities in their vascular network structures,” report the authors in the journal Biomaterials. “The development of decellularized plants for scaffolding opens up the potential for a new branch of science that investigates the mimicry between plant and animal.”
That would be good news for many patients in need of life-saving organ transplants. “More than 100,000 patients can be found on the donor waiting list at any given time and an average of 22 people die each day while waiting for a donor organ or tissue to become available,” report the authors.
Because spinach and other vegetables are abundant, they also have the potential to limit the costly and ethically questionable testing that’s currently done on animals. “The abundance and rapid growth of many plant species also provides for a less costly, more plentiful and sustainable scaffold material,” they report.
The researchers at Worcester Polytechnic Institute are continuing studies on how to “optimize the decellularization process” and are planning to test additional types of human cells.