By Jeanne du Plessis

Several lab-grown bladders have already been successfully implanted in human patients, and as recently as 2011, the first transplant of a completely lab-grown windpipe took place.

You’ve probably seen the disturbing image of the hairless mouse with a human ear growing on its back. The Vacanti mouse was named after its creator, Dr Charles Vacanti, a surgeon-scientist in the field of tissue engineering. It looks like something straight out of Dr Frankenstein’s lab but it’s also become an iconic image of tissue engineering, the science which allows researchers to grow organs in laboratories. While it sounds like science fiction, lab-grown organs are already a reality.

The challenges of transplants

Organ transplants have come a long way since the first transplant in 1954, but the same challenges still exist. Thousands of people all over the world are waiting for organ transplants, and there aren’t nearly enough donor organs. If an organ does become available, there’s the risk of rejection. This happens when the body’s immune system attacks the new organ as it would an invading germ. Transplant patients have to take drugs to suppress their immune system for the rest of their lives. These drugs increase the risk of high blood pressure, cancer, kidney failure and diabetes, and they don’t guarantee organ acceptance. Another problem is that the “new” organ isn’t really new. As it’s already been used for years, it’ll have its own damage along with diseases and pathogens accumulated over the donor’s lifetime.

Brand new, custom-made organs

What if people could simply order a custom-made, personalised organ? This is the promise of lab-grown organs. These man-made organs don’t have the accumulated wear-and-tear of donor organs. There’s also a much lower chance of rejection as they’re grown from the patient’s own cells, so the patient’s immune system doesn’t see them as foreign objects.

How

First, a small amount of living tissue or stem cells are taken from the patient. These cells go into lab dishes where they’re bathed in a fluid that makes them multiply. When there are enough cells, they go into a synthetic scaffold. The scaffold is nurtured in an incubator where the cells continue to multiply, growing into three-dimensional tissue. When ready, the new organ is transplanted into the patient. The scaffold gradually dissolves and the lab-grown tissue becomes indistinguishable from its surroundings. There are variations on the exact procedure; researchers use different tissue culture growth mediums and various scaffolds, and different organs seem to require different techniques. Some labs grow cells in dishes, other labs spray cells onto a scaffold. Whatever the technique, the end result is a new organ grown from the patient’s own cells.

Spare parts

In the future, will we be able to order custom-made “spare parts” to replace any organs or body parts that become diseased or damaged? Researchers are discovering that almost any biological material can be lab-grown. So far they’ve had the most success with bladders. Several lab-grown bladders have already been successfully implanted in human patients, and as recently as 2011, the first transplant of a completely lab-grown windpipe took place. However, the science is not yet perfect. Apparently bladders are relatively easy to grow, while more complex organs such as hearts and kidneys are proving more difficult.

Researchers are making progress though. They’re working on growing about 20 other types of tissues and organs, including blood vessels, the kidney, liver, pancreas and heart. They’ve already made functional lungs and a beating heart for rats. Researchers are confident that in the future, lab-grown hearts and even brains will become possible. They’re also looking into the amazing task of re-growing arms and legs. The possibilities are endless. You probably won’t be able to order a new heart from your local lab for several years, possibly decades, but lab-grown organs will certainly change the face (or heart or kidney) of modern medicine!