At any given time in the United States, there are approximately 120,000 patients waiting for a lifesaving organ donation and on average, 22 patients on this list die every day. The lack of available tissue for donation is a pressing problem in medical science today, and despite the ability for researchers to now grow large-scale human tissue in a laboratory, complex problems such as the growth of delicate blood vessels have not yet been overcome. However, a study published in Biomaterials this month by researchers from Worcester Polytechnic Institute reveals what may be a viable substitution for these intricate blood vessel networks – and the story starts with a salad.
Spinach leaves have a delicate network of thin veins that transport nutrients to every edge of its surface, making them an ideal imitation for the system that researchers need to recreate. The researchers from Worcester have shown that it is possible to mimic the function of the human heart using the humble spinach leaf by re-engineering it with human cells in the laboratory.
“The main limiting factor for tissue engineering is the lack of a vascular network” states co-author Joshua Gershlak. “Without that vascular network, you get a lot of tissue death.” Gershlak states that he found inspiration for a solution to this issue over lunch, “When I looked at the spinach leaf, its stem reminded me of an aorta. So I thought, let’s perfuse [the fluids] right through the stem.” By stripping the spinach leaf of its plant cells in the laboratory to leave only a cellulose frame, the study’s researchers were able to use the leaf as scaffolding on which to grow human tissues and create an organ resembling a mini human heart. And yes, the spinach leaves were simply purchased from the local supermarket. The success of this study suggests that in the future, multiple layers of these spinach leaves could be used to grow healthy heart muscle to treat heart attack patients.
If the idea of fusing plant material to human tissue may seem bizarre, the study’s researchers assert that, “Cellulose is biocompatible [and] has been used in a wide variety of regenerative medical applications, such as cartilage tissue engineering, bone tissue engineering and wound healing.” However, it remains to be seen whether the spinach scaffolds specifically will be safe for human use and whether or not some patients will develop an immune response to tissue grown on these re-engineered leaves.
The researchers also suggested that other plant material such as the jewelweed plant and its “cylindrical, hollow structure of the stem” could be used as an artery graft and even that wood from trees may prove useful in bone engineering. “By exploiting the benign chemistry of plant tissue scaffolds, we could address the many limitations and high costs of synthetic, complex composite materials”.
While the study concedes that there is a lot more work to be done, the technique looks extremely promising and these modified leaves could one day deliver oxygen to a large mass of replacement tissue. By adapting a plant that is extremely abundant, the researchers are optimistic that the spinach leaf could solve a whole host of problems facing the field of tissue transplants such as availability and cost in order to save a multitude of lives.