There's been a potential breakthrough in making organs in the lab. Israeli researchers have 3D printed a heart, complete with muscle and blood vessels. But how long before it is ready for actual use? Not for a while, according to Dr. Max Gomez of CBS New York.

Printing an organ is much more complicated than squirting a bunch of cells into the shape of a heart or kidney.

That said, researchers at Tel Aviv University have taken a big step toward off-the-shelf organs.

Get Breaking News Delivered to Your Inbox

Video shows a living heart being printed out. The 3D printing includes not just heart cells, but blood vessels and other supporting structures. It's a small heart, about the size of a rabbit's. Not only are the cells alive, but all of the different cell types in the heart came from a single human donor.

"That's important because it prevents the possibility of rejection," said Dr. Anthony Atala of the Wake Forest Institute for Regenerative Medicine.

Israeli scientist Tal Dvir from Tel Aviv University holds a transparent cup containing what the university says is the world's first 3D-printed, vascularized engineered heart, during a demonstration at a laboratory in the university, Tel Aviv, Israel, on Mon., April 15, 2019. Reuters

Dr. Atala is a pioneer in 3D printing of organs and tissues. He explained that the cells that made the heart came from a donor's fat tissue, which were then transformed into stem cells, and then differentiated into the various cell types in the heart.

Those cells are then printed into a biodegradable scaffold, or skeleton, that gives it its shape.

While it looks like a heart, structurally, it's not yet functional and doesn't pump.

"A functioning heart has to contract and be connected to vessels to be functioning," Dr. Atala said.

The first printed organs and tissues for actual human use will be simpler: Bladders, ears, blood vessels and windpipes, some of which have already been in implanted in patients, said Dr. Atala.

A 3D printer prints what Israeli scientists from Tel Aviv University say is the world's first 3D-printed, vascularized engineered heart. Reuters

The more immediate value of the Israeli work is to make what they call a cardiac patch, a piece of functioning heart tissue to repair heart attack damage.

That heart patch, which has an innate ability to contract, can integrate into the heart much more easily than building an entire heart which has to contract in a coordinated manner. Atria and ventricles have to pump in a precise sequence for blood to be pumped efficiently.