Hearts On Demand Mass General Surgeon Makes Critical Strides in Regenerating Organs
It’s the worst part of Dr. Harald Ott’s day: telling a patient suffering from end-stage heart disease that there’s not much he can do. But that heartbreaking conversation also inspires the Massachusetts General Hospital cardiothoracic surgeon and Charles and Sara Fabrikant MGH Research Scholar to pursue his lifelong goal— growing new hearts in a lab, so he’ll never have to have that talk again.
More than 5 million people in the United States live with heart failure, and nearly 4,000 patients are awaiting a new heart. About half of those patients will die awaiting a transplant. Dr. Ott’s research at Mass General points to a day without wait lists. Last year Dr. Ott and his team made waves when they built a human heart, shocked it with electrical impulses and got it beating.
What’s more, his innovative technique could work for virtually any human organ—not just the heart.
Building on a Scaffold
For over a decade, scientists have known how to coax stem cells into the cells of various organs in a lab. But a complex organ can’t be grown in a petri dish. Dr. Ott found a way to take an organ that is unsuitable for transplant and strip it of its native cells, leaving a collagen-based scaffolding called an extracellular matrix. He then fills the matrix with stem cells that can grow into a functioning organ. The whole process takes place in a bioreactor that simulates the environment inside the human body.
The process sounds miraculous, but it solves only part of the problem because the body rejects organs from a foreign source. Today’s transplant patients must spend a lifetime on debilitating drugs to suppress the body’s immune response to their donor’s organ.
When Dr. Ott started his work on organ regeneration, embryos were the only source of stem cells. Fortunately, researchers led by Nobel prize- winner Shinya Yamanaka discovered how to reprogram adult cells into stem cells. This will allow Dr. Ott to build a new organ made from the cells of the patient who will be receiving it, so it won’t be rejected. What’s more, Dr. Ott does not require a human scaffold to make a new organ; pig organs will do.
Since he founded his lab at Mass General Hospital in 2005, Dr. Ott and his team have regenerated functioning tissue onto the scaffolds of a liver, lung, kidney and pancreas, in addition to a heart. The team has further progressed from working with rodent to human organs. The next big challenge is building organs strong enough to function for a lifetime inside a human body.
Revolutionary New Options for Patients
Well before that day arrives, Dr. Ott’s research could contribute to efforts toward restoring ailing organs. Imagine, for example, if doctors could “patch” a damaged organ with tissue cloned from the patient’s own body. Dr. Ott and his colleagues at Mass General were encouraged last year when the U. S. Food and Drug Administration established a new program to promote the development and approval of regenerative medical products called the Regenerative Medicine Advanced Therapy Designation.
Cloned human organs could have many uses, even if they’re never implanted in a patient. They could be used to test new drugs and devices, reducing the need for animal subjects. They could even be used to test the safety and effectiveness of a drug or device on a specific patient, using a clone of the patient’s own organ. Such a test would be crucial because many therapies work differently on different patients.
“About one in five people will suffer from organ failure within their lifetimes,” says Ott. “That really underscores the need for options beyond transplanting organs or helping patients get by with greatly reduced organ function. We need treatments that actually replace lost function. What I hope as a surgeon is that within my lifetime, I will be able to implant living, regenerated organ replacements in my patients.”
What I hope as a surgeon is that within my lifetime, I will be able to implant living, regenerated organ replacements in my patients.” —Dr. Harald Ott