COURTESY OF TAKASHI TSUJI, TOKYO UNIVERSITY OF SCIENCE
For the first time, a complete organ generated from stem cells—a mouse tooth–has been successfully transplanted into a living adult mouse and exhibited normal function. Prior to this demonstration, stem cells had shown promise in producing tissues for repair of damaged organs, but were not sufficiently complex to grow a complete organ for transplant.
The study, published online yesterday (July 12) in PLoS One by researchers at Tokyo University of Science, built upon previous research that used stem cells from a donor mouse to produce the various tissues of a complete tooth unit—the tooth plus surrounding gum tissue and bone. Now, the team has added to those results by successfully transplanting the bioengineered tooth unit into a hole in a mouse’s jaw from which a functional tooth had been extracted, and demonstrating normal durability, cellular differentiation, regeneration of blood vessels and nerve fibers, root extension, and growth of surrounding bone. The transplants appeared to be fully integrated and still functional after 40 days.
This study serves as a proof of concept that complete organs can be grown from harvested stem cells and, when transplanted, achieve normal function, the authors said, hopefully advancing the field from stem cell transplantation for organ repair towards full organ replacement.