http://www.businessinsider.com/spinach- ... ood-2017-3
Researchers have successfully used spinach leaves to build functioning human heart tissue, complete with veins that can transport blood.
To tackle a chronic shortage of donor organs, scientists have been working on growing various tissues and even whole organs in the lab. But culturing a bunch of cells is only part of the solution - they simply won't thrive without a constant blood supply.
It's notoriously difficult to build a working network of fine blood vessels (also called vasculature), especially when you get down to capillaries, which are only 5 to 10 micrometres wide. Blood vessels transport the oxygen and nutrients that a lab-grown tissue sample needs to grow and function.
Now a team led by scientists from Worcester Polytechnic Institute (WPI) have successfully turned a spinach leaf into living heart tissue by using the tiny network of veins you'd already find in a plant.
"Plants and animals exploit fundamentally different approaches to transporting fluids, chemicals, and macromolecules, yet there are surprising similarities in their vascular network structures," the scientists write in their paper.
Instead of trying to build a vasculature from scratch, the researchers stripped their spinach leaves of green plant material until all that was left was the fine cellulose structure that holds the leaf together.
Cellulose from plants is a great material to use in lab-grown samples because it has been well studied, is compatible with living tissue, and is cheap to get your hands on, since many plants are abundant and easy to grow. For this study, the scientists literally bought spinach at the local market.
To access the fine vascular structure of spinach, the team circulated a detergent solution through the leaves to wash the plant cells away in a process called decellularisation.
"I had done decellularisation work on human hearts before, and when I looked at the spinach leaf its stem reminded me of an aorta," says lead researcher Joshua Gershlak.
"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."
To test the cellulose scaffolds in a real tissue sample, they ended up using spinach because it has a high concentration of vessels the way heart tissue does.
The researchers seeded the salad leaf vascular structure with heart muscle cells, and were excited to see that within a few days, the heart cells started to spontaneously contract just like they would in human tissue.
"The idea here is that we have this very thin, flat piece of tissue that already has a vascular network in there, so we should be able to potentially stack up multiple leaves and create a piece of cardiac tissue," says Gershlak.