New developments in the world of human organ transplantation re: the American Tranplant Congress

First Autologous Organ Only a Matter of Time

Doris Taylor, PhD: ‘This approach is applicable to virtually any organ or tissue, pig or human-sized.'

The race is on to build the first complex organ. Describing what it will take to achieve this momentous milestone was Doris Taylor, PhD, Director of the Center for Cardiovascular Repair, Medtronic Bakken Professor of Integrative Biology and Physiology, and Professor of Medicine at the University of Minnesota, during Monday's State-of-the-Art Address, "Rebuilding Autologous Organs: Cells, Scaffold, Organ."

During her lecture, she described in depth the concept for rebuilding an organ, which involves collecting appropriate types and numbers of cells, selecting the right scaffold, decellularizing the scaffold and seeding the scaffold with the cells. When this concept works, the end result is an organ that performs its appropriate function.

"I believe we have proven that the concept is feasible and that you can scale it up to human-sized organs," she said. "The idea of moving this forward clinically is going to require large numbers of cells and choosing the right scaffold. There is a lot of science to be done, but it is moving at a rapid pace."

Dr. Taylor discussed her group's groundbreaking work with the heart and liver. Most notably in 2008, her lab developed a process called whole-organ decellularization and created a beating heart in the laboratory. This process involved rinsing all cells away from a rat heart and reseeding the remaining heart scaffold with a mixture of cells.

"This approach is applicable to virtually any organ or tissue, pig or human-sized," she said. "One day, we might ultimately consider building organs based on pig scaffolds using human autologous cells."

Her recent efforts have involved collaboration with scientists in Spain to research comparisons between decellularized cadaveric human and pig hearts to build scaffolds and to collect the first decellularized human data. Dr. Taylor and her Spanish partners have stripped cells from 10 human hearts and are beginning to seed them with different types of human cells to see how they react. In her laboratory, she will use decellularized cadaveric pig heart scaffolds and seed those with human cells in an effort to create a functioning human heart.

"Removing the cells from a cadaveric organ has solved the scaffold problem," Dr. Taylor said. "Now the question is what cells do you put on the scaffold and how do you get them to grow up to believe they are a particular organ. That's the rate-limiting step now. It's going to take discovery organ-by-organ."

Currently, cell choices are adult, embryonic and umbilical cord blood stem cells, bone marrow and fat tissue. Her best estimate at this juncture is bone marrow or blood derived-cells will be used for building vasculature, though other organs, such as a kidney or pancreas, will require different kinds of cells.

Histocompatibility has not been entirely resolved, either.

"It certainly is our goal," Dr. Taylor said. "We are theorizing that only short-term immunosuppression will be needed because the recipient's own cells are used in building organs."

Thanks to her groundbreaking research, other scientists are applying her findings in their own labs in a race to rebuild the first organ.

"If I have anything to do with it, the first rebuilt organ will be either a liver or a heart," Dr. Taylor said. "We anticipate seeing a complex organ in first in-human use within the next five years. Still, much must happen, though we've made huge progress. Also, we must do this safely because we owe it to the world to do this responsibly and correctly."