AsianScientist (Apr. 5, 2016) – Using induced pluripotent stem (iPS) cells, scientists in Japan have successfully grown complex skin tissue, complete with hair follicles and sebaceous glands, in the lab. They were then able to implant these three-dimensional tissues into living mice, where they formed proper connections with other organ systems such as nerves and muscle fibers.
This work, led by scientists at RIKEN and published in Science Advances, opens a path to creating functional skin transplants for burn patients or those who require new skin.
Research into bioengineered tissues has led to important achievements in recent years, with the creation of a number of different tissue types, but there are still challenges to be addressed. In terms of skin tissue, epithelial cells have been successfully grown into implantable sheets, but they did not have the proper appendages, such as oil-secreting and sweat glands, that would allow them to function as normal tissue.
To overcome this, the researchers took cells from mouse gums and used chemicals to transform them into stem cell-like iPS cells. In culture, the cells properly developed into what is called an embryoid body (EB)—a three-dimensional clump of cells that partially resembles a developing embryo.
The researchers then implanted the 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 them out of those mice and into the skin tissue of other mice, where the tissues developed normally. Critically, they also found that the implanted tissues made normal connections with the surrounding nerve and muscle tissues, allowing it to be fully functional.
One important key to the development was treatment with a signaling molecule called Wnt10b, which resulted in a larger number of hair follicles and made the bioengineered tissue closer to natural tissue.
“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. With this new technique, we have successfully grown skin that replicates the function of normal tissue,” said Dr. Takashi Tsuji of the RIKEN Center for Developmental Biology, who led the study.
“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.”
The article can be found at: Takagi et al. (2016) Bioengineering a 3D Integumentary Organ System from IPS Cells Using an in vivo Transplantation Model.
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Source: RIKEN; Photo: Shutterstock.
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