Tufts University researchers have created tissues that mimic human skin and the moist tissue that lines the inside of the mouth using human embryonic stem cells, paving the way for possible therapies to replace damaged tissues. Using a combination of chemical nutrients and specialized surfaces for cell attachment, the researchers directed a human embryonic stem cell line to form two distinct specialized cell populations—the mesenchymal and surface layer.

 

After isolating and characterizing the cell populations, the researchers then incorporated them into a three-dimensional tissue system where they were grown at an air-liquid interface to mimic their growth environment in the oral cavity. Within two weeks, tissues developed that were similar in structure to those constructed using mature cells derived from newborn skin, the researchers report in the study published in Tissue Engineering Part A.

 

“Researchers have been seeking methods to grow skin-like tissues outside of the body using new sources of stem cells such as [human embryonic stem cells], with the goal of advancing regenerative medicine as a new therapy to replace or repair damaged or diseased tissue,” says Jonathan Garlick, professor of Oral and Maxillofacial Pathology at Tufts University School of Dental Medicine. “Little is known about how [human embryonic stem cells] can be developed into the multilayer tissues similar to those that line the gums, cheeks, lips, and other areas in the mouth. We used in vitro tissue engineering techniques to produce skin-like tissues that mimic the lining tissues found in the oral cavity.”

 

Because of their pluripotency—or their ability to differentiate into virtually any cell found in the human body—human embryonic stem cells are being looked at for use in a variety of different therapies, including the repair of damaged organs and the mending of broken bones. In the United States, researchers had been stymied by Bush Administration restrictions that limited research using human embryonic stem cells, but President Obama’s reversal of the policy earlier this year has energized the field. Also earlier this year, the U.S. Food and Drug Administration gave approval to the biotech company Geron to begin the first human clinical trial involving human embryonic stem cell therapy. Geron is developing a treatment for spinal cord injury.

 

As for the latest skin tissue research, Garlick, who is also a member of the Cell, Molecular and Developmental Biology program faculty at the Sackler School of Biomedical Sciences at Tufts, says the newly created tissues are remarkably similar to human tissues.

 

“We can now use these engineered tissues as ‘tissue surrogates’ to begin to predict how stable and safe [human embryonic stem cells]-derived cells will be after therapeutic transplantation,” he says. “Our goal is to produce functional tissues to treat oral and skin conditions, like the early stages of cancer and inflammatory disease, as well as to accelerate the healing of recalcitrant wounds.”