For severe burn victims and others in need of skin transplants, current treatments using artificial skin grafts made from sheets of lab-grown skin cells aren’t ideal because they lack the complex structures needed to fully restore many of the skin’s critical functions.

For example, artificial skin doesn’t contain oil-producing sebaceous glands, forcing burn victims to apply oil to their skin grafts to prevent them from drying out and losing their natural cushioning and waterproof properties.  Without the replacement of sweat glands and hair follicles within the skin tissue, the graft regions don’t adequately regulate body temperature. The sense of touch is often lost because disrupted nerve fibers aren’t reconnected to the transplanted skin.

The lack of a genuine skin replacement has emotional consequences too since skin grafts often don’t match up with surrounding skin and leaves victims disfigured. So, while current treatments help, the field is busily looking for new and better solutions.

New skin in the game

As reported in the latest issue of Science Advances, a research team from the RIKEN Center for Developmental Biology in Japan has taken a major step in the right direction by generating a fully functional 3D skin organ system in mice using stem cells.

The team accomplished this feat by first collecting gum cells from the mouse’s mouth and reprogramming them into induced pluripotent stem cells (iPS) that can specialize into any cell type in the body. After a few days in a petri dish, the iPS cells formed into embryoid bodies, clumps of cells that contain a random mix of cell types that would be seen in a developing embryo, including those that give rise to skin. Then, using a novel transplantation method, a cluster of several embryoid bodies were encased together in a gel and then transplanted into mice where theyresearchers encased a cluster of embryoid bodies in a gel and transplanted it into mice, where it could grow for later testing.

Skin that sweats and grows hair

The embryoid body clusters were allowed to develop further in mice for a month. The transplants were then taken out, and their cellular structure and gene activity were analyzed. The results confirmed the formation of a complex, three-dimensional skin organ system complete with all three skin layers as well as hair follicles, sweat glands, oil-producing sebaceous glands, and fat tissue.

In follow-up experiments, the researchers transplanted small pieces of this tissue into the skin of another set of mice. After 14 days, the researchers observed new hair growth from the follicles of the transplanted tissue. They also showed that the hair follicles had made the necessary connections to muscle tissue and nerve fibers of the host mice.

Future directions

This work aims to create skin grafts that function as a full organ system, not just a flat layer of cells.

In a press release, study leader Takashi Tsuji noted that skin transplants are only one potential use. “With this technique, we have grown skin that replicates normal tissue function. We are getting closer to creating organs in the lab for transplantation, and tissue from this method could also replace animal testing.”

And with restored hair follicles, maybe my fellow bald brethren could one day regain a full head of hair.