12 years ago some smart people modified an inkjet printer and cartridge to enable it to print out living tissue. Since then, working heart valves, liver tissue and kidneys have been made outside the body using the body’s own cells. In 2011, Anthony Atala, a surgeon at the Wake Forest Institute of Regenerative Medicine presented one of the then most popular Ted Talks (embedded above) discussing regenerative tissue engineering. Now, 2015 is likely to see the first transplant ready 3D printed organ. Tissue Engineering and 3D bioprinting get round one of transplant medicine’s biggest problems, compatibility. Often, they can’t just transplant anyone’s organ into you, it has to be a match for your body otherwise your body’s immune system will reject it and attack it. Even successful transplant recipients are often long on immunosuppressant drugs. 3D printing organs gets around this by using your own cells to grow you new tissue. Since it’s your own cells being used to grow you new tissue, the chance of your body rejecting the new tissue is greatly reduced. In an over simplified nutshell here’s how it works; Say a patient is in need of some new tissue or replacement organs, instead of getting on the transplant wait list and waiting for a compatible donor organ to be found, a sample of the patients own existing tissue is taken out and the cells separated. These cells are then multiplied in a nutrient bath. The cells are then added to a scaffold where they will multiply into the desired shape. In 2008, researchers at the University of Minnesota showed that it is possible to remove all the cells from an organ using enzymes and detergents(yes detergents!) in a process called decellularization which exposes what is called the extracellular matrix (ECM) which is the scaffold that provides structural and biochemical support to the surrounding cells. In 2013, another group of researchers took it a step further. They stripped a mouse’s heart of it’s cells exposing its translucent ECM. They then went ahead to inject the mouse ECM with Human heart cells and provided nutrients for the heart cells to multiply. 20 days later the human heart cells had multiplied into the mouse ECM and the had a beating mouse heart made up of human heart cells. The potential of tissue engineering is a future where if you need a heart transplant, your own cells could be used to grow you a new heart in a lab over a few weeks instead of waiting months or years for a compatible transplant candidate. Even if your organs are just old, cells preserved from your younger days could be used to grow you younger organs. Tissue engineering doesn’t only apply in medicine, it can also be used to create lab grown meat for consumption (Which we’ll cover in-vitro meat later in Future 101). Further ahead we might be able to engineer less homogenous parts of the body like entire limbs. There are still many challenges to overcome however many research institutes and companies like Organovo are investing and steadily advancing the field beyond what we thought possible a few years ago. I for one, will welcome our faux meat future! I wonder what vegetarians will say about petri dish meat that an animal didn’t have to die for!
