Stem cells are generic cells that have the ability to become any kind of specialized cell in the body. As such, they hold tremendous value in medicine; they could be used to regrow organs or to heal devastating injuries, among many other things. But finding a rich source of these cells has been challenging. New work has shown that a large number of stem cells, potentially enough for clinical use, can be extracted from tooth root pulp.
“Stem cells can be extracted from nearly any living tissue. In fact, stem cells can even be found in tissues of the deceased,” noted Dr. James Mah. He is the Director of the Advanced Education Program in Orthodontics, a doctor of dental surgery, and a dental researcher at UNLV who worked on this project. “The biggest challenges with stem cells are gathering enough of them to work with and keeping them viable until they are needed,” Mah explained.
As a dental researcher, he knew that teeth could be a great resource. He enlisted the help of UNLV Biomedical Sciences Professor Karl Kingsley and their research teams to find a way to harvest stem cells from a seemingly endless repository: wisdom teeth.
“More and more adults—approximately 5 million throughout the country—have their wisdom teeth, or third molars, removed,” Kingsley said. “Extracting teeth is relatively common among patients undergoing orthodontic treatments. And the majority of those teeth are healthy, containing viable tooth root pulp that offers opportunities for reproducing cells that have been damaged or destroyed by injuries or disease.”
Tooth root pulp contains two kinds of stem cells, and the researchers would have to extract them carefully to keep them viable. It took the invention of a new tool, jokingly dubbed the “Tooth Cracker 5000.” Conceptualized by dental student Happy Ghag, engineering students helped create it.
“Happy had reviewed fracture mechanics literature and decided on a technique that scored the tooth to enable a clean break, similar to the process for custom-cut glass,” said Brendan O’Toole, Mendenhall Innovation Program Director, and mechanical engineering researcher. Now the team could break teeth perfectly, into two halves, without contaminating the pulp.
They then put the tool to the test. “Saying the test results were promising is a gross understatement,” said Mah. “We realized we’d invented an extraction process that produced four times the recovery success rate for viable stem cells. The potential application is enormous.” Learn more about this work from the video.
The researchers cultured the cells they'd obtained, splitting the dish in half and repeating the process ten to twenty times. Any cells that were not of the stem cell variety died by the end of that process, and the researchers then harvested the RNA from the remaining stem cells to characterize them.
“Scientists around the world are trying to figure out what type of stem cells can be coaxed into becoming new cells or different tissue types,” Kingsley explained. “We already know some populations of dental pulp stem cells can be converted into neurons, which could become therapies for cognitive diseases such as Alzheimer’s or Parkinson’s.”
Stem cells are currently being tested to treat various neurological disorders in animal models, Kingsley said. A lot more work is needed, but initial results have been encouraging.
“There are potential applications of stem cells for multiple diseases, including cancer, arthritis, and lung disease,” Kingsley said. “The next challenge is reliably collecting the stem cells early enough and storing them successfully so they can be used when needed.”
The researchers are also interested in improving our understanding of stem cell viability so that they can be stored and thawed for later use.
“The work Dr. Kingsley and I are doing is part of a paradigm shift. Our fracturing process could hasten the collection and cryogenesis process, thereby preserving a high stem-cell count that furthers research into how using these cells can aid healing and potentially cure diseases,” Mah concluded.