The scientists also say these cells have "tremendous potential" to regenerate the periodontal ligament, a common target of advanced gum (periodontal) disease. This enthusiasm is based on follow up experiments, in which the researchers implanted the human adult stem cells into rodents, and most of the cells differentiated into a mixture of periodontal ligament -including the specific fiber bundles that attach tooth to bone - and the mineralized tissue called cementum that covers the roots of our teeth.

"The stem cells produced beautifully dense, regenerated tissue in the animals," said Dr. Songtao Shi, a senior author on the paper and an NIDCR scientist. "That was when we knew they had great potential one day as a treatment for periodontal disease, and we're continuing to follow up on this promise with additional animal work." The results are published in the current issue of The Lancet.

Shi said scientists have suspected since the 1970s that the periodontal ligament might contain its own unique stem cells. But, for a variety of technical reasons, the search had come up empty, leaving some to wonder whether stem cells could be extracted from such a tiny bit of tissue known to contain a confusing mixture of cell types and subsets.

About two years ago, Shi said he and his colleagues decided to take a stab at the problem. They obtained 25 newly extracted third molars, or wisdom teeth, and gently tugged the ligament free from the root of the tooth. Through trial and error, the group successfully extracted, sorted, and cultured the various cells from the tissue, hoping they had isolated stem cells in one of their many P
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Contact: Bob Kuska
kuskar@nidcr.nih.gov
301-594-7560
NIH/National Institute of Dental and Craniofacial Research
8-Jul-2004