Scientists have successfully grown complex skin tissue—complete with hair follicles and sebaceous glands—in living mice in a laboratory in Japan.
Researchers at the RIKEN Center for Developmental Biology in collaboration with Tokyo University of Science and other Japanese institutions used reprogrammed iPS cells and implanted these three-dimensional tissues into mice. The tissues formed proper connections with other organ systems such as nerves and muscle fibers.
The authors suggest that their work opens a path to creating functional skin transplants for burn and other patients who require new skin. Their study was published in the journal Science Advances ( Apr. 1, 2016; 2(4):e1500887).
“Up until now, artificial skin development has been hampered by the fact that the skin lacked the important organs, such as hair follicles and exocrine glands, which allow the skin to play its important role in regulation,” said Takashi Tsuji, PhD, who led the study, in a press release. “With this new technique, we have successfully grown skin that replicates the function of normal tissue. We are coming ever closer to the dream of being able to recreate actual organs in the lab for transplantation, and also believe that tissue grown through this method could be used as an alternative to animal testing of chemicals.” He is with the RIKEN Center for Developmental Biology.
The researchers harvested cells from mouse gums and used chemicals to transform them into stem cell-like iPS cells. In culture, the cells properly developed into an embryoid body (EB). The researchers created EBs from iPS cells using Wnt10b signalling and then implanted multiple EBs into immune-deficient mice, where they gradually changed into differentiated tissue, following the pattern of an actual embryo.
Once the tissue had differentiated, the scientists transplanted the tissues out of those mice and into the skin tissue of other mice, where the tissues developed normally as integumentary tissue.
According to the press release, one important key to the development was that treatment with Wnt10b, a signalling molecule, resulted in a larger number of hair follicles, making the bioengineered tissue more similar to natural tissue.