May 14, 2013
Alligator Ability To Regrow Teeth May Eventually Help Humans
Michael Harper for redOrbit.com — Your Universe Online
Though we´re in many ways at the top of the evolutionary heap, humans have a number shortfalls left to overcome. Medical science has been hard at work over the last several decades to lengthen our lifespans, but in the end we´re mostly limited to only what was given us at birth. Teeth, for instance, are a limited resource in humans. We get one set as children which are later replaced with adult teeth which we wear until they finally fall out.
Dr. Cheng-Ming Chuong, a professor of pathology with the University of Southern California Keck School of Medicine has been looking to other animals to understand how they are capable of growing numerous sets of teeth in their lives with the hopes of bringing some of that knowledge to the human mouth. Dr. Chuong and his global team of researchers finally found the prime candidate for their study — the American alligator.
This watery vertebrate can regenerate its teeth 50 times during its life, a feat which this research team attributes to cellular and molecular mechanisms. The resulting study, entitled “Specialized stem cell niche enables repetitive renewal of alligator teeth,” was recently published in the Proceedings of the National Academy of Sciences.
In a statement, Dr. Chuong lamented the poor teeth-growing skills of humans, despite having the appropriate material to make more teeth in the future. By thoroughly examining the alligator mouth, Dr. Chuong hopes to uncover the mysteries of this beast´s teeth.
“Ultimately, we want to identify stem cells that can be used as a resource to stimulate tooth renewal in adult humans who have lost teeth. But, to do that, we must first understand how they renew in other animals and why they stop in people,” said Dr. Chuong.
An alligator´s teeth are surprisingly similar to human teeth both in form, organization and structure.
“Alligator teeth are implanted in sockets of the dental bone, like human teeth,” said first author Ping Wu, PhD, assistant professor of pathology at the Keck School of Medicine.
“They have 80 teeth, each of which can be replaced up to 50 times over their lifetime, making them the ideal model for comparison to human teeth.”
As the research team looked closely at alligator teeth, they noticed each tooth is composed of three sections: A functional tooth, a new growing tooth to replace it, and dental lamina, the material which promotes tooth growth. These teeth are constantly developing in one of these three sections, so when an alligator loses its tooth, the next section is ready to progress and replace the missing tooth. The bottom section, the dental lamina, is where the researchers found crucial stem cells which they believe are responsible for fueling the tooth-making factory.
“The cells in the alligator´s dental lamina behaved like we would expect stem cells to behave. In the future, we hope to isolate those cells from the dental lamina to see whether we can use them to regenerate teeth in the lab,” said Randall B. Widelitz, PhD, co-author of the study and associate professor of pathology at the Keck School.
The researchers hope that if they´re able to dissect and understand the molecular networks involved in regenerating these teeth, they´ll be able to apply this knowledge to the human mouth. This could lead to the regeneration of human teeth even after we´ve already lost the last set nature gave us.