Recent research aimed at finding a treatment for a common form of blindness could give new meaning to the term “eye teeth.” In a study in mice published in STEM CELLS Translational Medicine, researchers at the University of Pittsburgh show how stem cells harvested from teeth extracted during routine dental procedures can potentially be used to restore sight in those suffering from corneal blindness.
Corneal blindness afflicts millions of individuals worldwide. It occurs when the cornea becomes scarred and cloudy and light cannot penetrate the eye to reach the light-sensitive retina. Since corneal scarring is largely irreversible, the most common method of treatment is to graft a new cornea using tissue taken from cadavers. Given that there is a worldwide donor shortage and that many grafts are eventually rejected because they are not the patient’s own tissue, researchers have been looking for a new source for such tissue or a new way to regenerate the patient’s own cornea. (The current failure rate of corneal grafts is about 38 percent after 10 years, primarily due to tissue rejection.)
The University of Pittsburgh team, led by James L. Funderburgh, Ph.D., and Fatima Syed-Picard, Ph.D., both in the Department of Ophthalmology, decided to focus on adult dental pulp stem cells (DPSC) as a possible solution.
“If we could generate an engineered cornea using autologous cells, which are the patient’s own cells, and then use that to replace scarred tissue, we could bypass the limitations of current treatments,” Dr. Funderburgh explained. “We thought dental pulp might be the answer, as other studies have proven that DPSCs can differentiate into various other cells and they already have a similarity to cornea tissue as they both develop in the embryo stage from the cranial neural crest,” he added. “That led us to believe that we might induce DPSCs to become corneal cells, too.”
The team began by collecting DPSCs from molar teeth discarded after routine extractions at the university’s dental school and then treated the cells in a special solution that caused them to differentiate into corneal cells, or “keratocytes.” When they tested the DPSC-generated keratocytes they found they had the same properties as those grown naturally in the human eye.
They then seeded the cells onto a corneal shaped nanofiber substrate to see if they could engineer corneal tissue. Four weeks later, the cells had grown into a structure that mimicked the complex organization of an actual cornea.
Their final task was to evaluate how the DPSC-generated keratocytes would perform by labelling them with a dye (for tracking purposes) and then injecting them into the right eyes of mice. (The left eye of each animal was injected with medium only, as a control.) When they tested the mice’s eyes five weeks later, they found that the DPSC-generated keratocytes had remained in the corneas and behaved similar to natural keratocytes. Their corneas were clear, and there were no signs of rejection.
“These studies provide promising data on the potential translation of DPSC as an autologous cell source for regenerative corneal therapies and possibly more,” Dr. Funderburgh concluded.
This study provides promising data on the use of adult dental pulp cells for personalized regenerative medicine to treat corneal blindness,” said Anthony Atala, M.D., editor of STEM CELLS Translational Medicine and director of the Wake Forest Institute for Regenerative Medicine.