Researchers grow heart tissue on spinach leaves!

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Photo credit: Worchester Polytechnic Institute
Photo credit: Worchester Polytechnic Institute

Spinach leaves are endowed with millions of nutrients providing tremendous health benefits. To add to it, researchers have now shown the use of spinach leaves in generating functionalized human heart cells. Although this still requires human testing, scientists at Worchester Polytechnic Institute (WPI) hope to use these modified spinach leaves for implantation to regenerate heart tissue in patients.

Shortage of organ and tissue donors is a global problem

There is a persisting need for organs and tissues for transplantation. An average of 22 people die every day while waiting for an organ or tissue from donors to become available. One of the approaches used by clinicians and researchers to get past this problem is bioengineering. Bioengineering involves use of artificial material or tissue for grafting or transplantation.

Using such type of material that can be produced artificially, will take away the need for donors completely. Although tissue engineering has made significant progress through the development of tissue grafts, one major roadblock is developing a functional blood system between the tissue grafted and the organ, which cannot be manipulated from outside.

Making grafts and implants from other biological material?

A team of biomedical engineers led by Professor Glenn Gaudette have recently shown the use of spinach leaves to build functional human heart cells. This study was recently published in the Biomaterials journal.

This whacky idea struck them when Professor Glenn Gaudette and his graduate student, Josh Gershlak, were eating lunch.  A piece of fresh spinach caught Gershlak’s eye. He noticed that the spinach leaf has a number of veins running through it, which is in turn connected to a larger, central vein, similar to the heart. “Josh came back to the lab and kind of secretly did this because we didn’t want people to think that we were crazy,” said Gaudette.

Left: Spinach leaf after decellularization showing an intact vein system. Right: Spinach leaf after loading red dye which suggests that the vein system can similarly pump blood thus transporting oxygen and other nutrients to heart tissues. Photo credit: Worchester Polytechnic Institute
Left: Spinach leaf after decellularization showing an intact vein system.
Right: Spinach leaf after loading red dye which suggests that the vein system can similarly pump blood thus transporting oxygen and other nutrients to heart tissues. Photo credit: Worchester Polytechnic Institute

Their crazy experiments were indeed fruitful. Briefly, Gershlak transformed the spinach through a process known as decellularization where they removed most of the cellular plant material using a detergent leaving behind a translucent, malleable substance, with an intact system of veins.

Photo credit: Worchester Polytechnic Institute
Photo credit: Worchester Polytechnic Institute

When the plant cells are washed away what remains is a framework made primarily of cellulose, a natural substance that is not harmful to people. “Cellulose is biocompatible (and) has been used in a wide variety of regenerative medicine applications, such as cartilage tissue engineering, bone tissue engineering, and wound healing,” the authors wrote.

Next, to see if the veins can sustain blood flow to human tissues upon grafting, Gershlak injected a red dye into the stem. The dye traveled throughout the veins, much like blood travels through human tissue.  As a final test, they planted heart cells on these modified leaves. Adding to their excitement, the cells started beating!

“We have a lot more work to do, but so far this is very promising,” Gershlak said. “To be able to just take something as simple as a spinach leaf, which is an abundant plant, and actually turn that into a tissue that has the potential for blood to flow through it, is really very, very exciting, and we hope it’s going to be a significant advancement in the field.”

According to them not just spinach, but a wide variety of other plants—from parsley to bamboo—may also have the potential to be engineered into life-saving materials. Well, it will no longer be surprising if we soon hear of broccoli and cauliflower that can form functionalized lungs!

In addition to spinach leaves, the team successfully removed cells from parsley, Artemesia annua (sweet wormwood), and peanut hairy roots. They expect the technique will work with many plant species that could be adapted for specialized tissue regeneration studies.

“The spinach leaf might be better suited for a highly vascularized tissue, like cardiac tissue, whereas the cylindrical hollow structure of the stem of Impatiens capensis (jewelweed) might better suit an arterial graft. Conversely, the vascular columns of wood might be useful in bone engineering due to their relative strength and geometries,” the authors wrote.

Using plants as the basis for tissue engineering also has economic and environmental benefits. “By exploiting the benign chemistry of plant tissue scaffolds,” they wrote, “we could address the many limitations and high costs of synthetic, complex composite materials. Plants can be easily grown using good agricultural practices and under controlled environments. By combining environmentally friendly plant tissue with perfusion-based decellularization, we have shown that there can be a sustainable solution for pre-vascularized tissue engineering scaffolds.”