The engineering of replacement organs is progressing. There are ongoing successes with less functional tissue masses such as the bladder wall and trachea, but sights are set on building complex organs such as the heart:
Since a laboratory in North Carolina made a bladder in 1996, scientists have built increasingly more complex organs. There have been five windpipe replacements so far. A London researcher, Alex Seifalian, has transplanted lab-grown tear ducts and an artery into patients. He has made an artificial nose he expects to transplant later this year in a man who lost his nose to skin cancer.
Now, with the quest to build a heart, researchers are tackling the most complex organ yet. The payoff could be huge, both medically and financially, because so many people around the world are afflicted with heart disease. Researchers see a multi-billion-dollar market developing for heart parts that could repair diseased hearts and clogged arteries.
In additional to the artificial nose, Dr. Seifalian is making cardiovascular body parts. He sees a time when scientists would grow the structures needed for artery bypass procedures instead of taking a vein from another part the body. As part of a clinical trial, Dr. Seifalian plans to transplant a bioengineered coronary artery into a person later this year.
Dr. Aviles trained as a cardiologist but became frustrated with the difficulty of treating patients with advanced heart disease. [He] was approached in 2009 by a U.S. scientist, Doris Taylor, who had already grown a beating rat heart in the [lab]. Instead of using a man-made scaffold, Dr. Taylor had used the scaffolding from an actual rat heart as the starting point.
Growing a heart is much harder than, say, growing a windpipe, because the heart is so big and has several types of cells, including those that beat, those that form blood vessels, and those that help conduct electrical signals. For a long time, scientists didn't know how to make all the cells grow in the right place and in the right order.
Dr. Aviles said he hopes to have a working, lab-made version ready in five or six years, but the regulatory and safety hurdles for putting such an organ in a patient will be high. The most realistic scenario, he said, is that "in about 10 years" his lab will be transplanting heart parts. He and his team already have grown early-stage valves and patches that could be used some day to repair tissue damaged by heart attack.