Since the days of Popeye the Sailor, spinach has been famous for its ability to make us “strong to the finish.” And while this leafy green won’t cause our biceps to inflate like balloons, it can do something equally as extraordinary—it can work like a heart.

Was Popeye on to something?

When you think about cutting-edge medical techniques, chances are that plants aren’t the first thing that springs to mind.

But maybe they should be. Because that’s exactly what researchers from Worcester Polytechnic Institute (WPI) in Massachusetts have been using as a platform for growing healthy heart tissue.

In a paper titled “Crossing kingdoms: Using decellularized plants as perfusable tissue engineering scaffolds,” the WPI team explains how greens like spinach could save a life (and not just if you eat them). Specifically, they’ve discovered that by taking the unique properties found within the plant kingdom they can potentially address long-standing problems in tissue regeneration.

One major issue in tissue regeneration is creating a vascular system that lets blood flow to the tissue and deliver all-important oxygen and nutrients. Current techniques like 3D printing—as innovative as they are—can’t yet create the blood vessels and tinier capillaries needed in a circulatory system.

So the team looked to the plant kingdom and found that spinach leaves, like the human body, possess a tiny, delicate vascular framework which moves fluids throughout: that is, veins.

Growing a heart from scratch.
Building on this discovery, the team removed the plant cells from a spinach leaf by flushing a detergent solution through its stem, leaving behind a “scaffold” made of cellulose—a safe, organic material that’s been used in many other regenerative efforts, including cartilage and bone tissue engineering. They then seeded live human cells onto the scaffold. Those cells successfully transformed around the spinach leaf into something resembling a tiny beating heart.

From there, the team was able to pump fluids and particles comparable in size to human blood cells through the scaffold, confirming that the veins could transport blood.

The future could look a lot greener—on the inside.
While this is all super cool and exciting, we’re still many years away from any salad-based heart patches. Nevertheless, it represents a major breakthrough for patients with severe heart conditions and in the medical field as a whole.

Some of the excitement stems from the idea of finally having a natural solution available for what’s been a limiting problem in regenerative medicine. The dream is that, through this technique, it’ll one day be possible for humans to quickly grow plants in different sizes and shapes for different tissue types.

For instance, jewelweed may work as an arterial graft, while wood could be used in bone engineering “due to their relative strength and geometries.” And, in Canada, one researcher is working on making ears out of apples.

“You are what you eat” has suddenly taken on a whole new meaning.