Natural reparative capacity of teeth elucidated

April 22, 2015
The dental pulp is shown in yellow. Credit: ©Inserm/ Chappard, Daniel

Researchers at Inserm and Paris Descartes University have just taken an important step in research on stem cells and dental repair. They have managed to isolate dental stem cell lines and to describe the natural mechanism by which they repair lesions in the teeth. This fundamental discovery will make it possible to initiate unprecedented therapeutic strategies to mobilise the resident dental stem cells and magnify their natural capacity for repair.

These results are published in the journal Stem Cells.

The tooth is a mineralised organ, implanted in the mouth by a root. The "living" part of the tooth or dental cavity is the dental pulp (in yellow in the photograph shown opposite) composed of vessels and nerves. Around it is a hard substance, the dentine or ivory, which is in turn covered by an even harder tissue, the enamel. When a dental lesion appears, the dormant stem cells in the pulp awaken and try to repair the tooth by an unknown process.In this study, the researchers from Inserm and Paris Descartes University at Unit 1124, "Toxicology, Pharmacology and Cellular Signaling," have succeeded in extracting and isolating tooth stem cells by working on the pulp from the mouse molar.

The researchers were thus able to analyse the cells in detail, and identify 5 specific receptors for dopamine and serotonin on their surface, two neurotransmitters that are essential to the body.

The presence of these receptors on the surface of these stem cells indicated that they had the ability to respond to the presence of dopamine and serotonin in the event of a lesion. The researchers naturally wondered what cells might be the source of these neurotransmitters, a warning signal. It turns out that the , activated by the dental lesion, are responsible for releasing a large quantity of serotonin and dopamine. Once released, these neurotransmitters then recruit the stem cells to repair the tooth by binding to their receptors. The research team was able to confirm this result by observing that dental repair was absent in rats with modified platelets that do not produce serotonin or dopamine, i.e. in the absence of the signal.

In response to a lesion, the pulpal stem cells respond to serotonin and dopamine released by the blood platelets to ensure repair of the dentine. This discovery provides the fundamental basis for developing therapeutic strategies to mobilize the resident pulpal stem cells in order to magnify the natural reparative capacity of the teeth. Credit: © Inserm / Odile Kellermann, Anne Baudry

"In , it is unusual to be simultaneously able to isolate , identify the markers that allow them to be recognised (here the 5 receptors), discover the signal that recruits them (serotonin and dopamine), and discover the source of that signal (blood platelets). In this work, we have been able, unexpectedly, to explore the entire mechanism," explains Odile Kellermann, leader of the team from Inserm and Paris Descartes University, and the main author of this work.

To take things a stage further, the researchers tried to characterise the different receptors they found. One of the 5 receptors does not seem to affect the repair process. On the other hand, the other 4 turn out to be strongly involved in the repair process. In vivo blocking of just one of them is enough to prevent dental repair.

"Currently, dentists use pulp capping materials (calcium hydroxide) and tricalcium phosphate-based biomaterials to the tooth and fill lesions. Our results lead us to imagine unprecedented therapeutic strategies aimed at mobilising the resident pulpal stem cells in order to magnify the natural reparative capacity of teeth without use of replacement materials," concludes Odile Kellermann.

The foundations have been laid for extending this research done in rodents to of the human tooth in order to initiate new strategies for repairing teeth.

Explore further: Stem cells from nerves form teeth

Related Stories

Stem cells from nerves form teeth

July 29, 2014
Researchers at Karolinska Institutet in Sweden have discovered that stem cells inside the soft tissues of the tooth come from an unexpected source, namely nerves. These findings are now being published in the journal Nature ...

Wisdom teeth stem cells can transform into cells that could treat corneal scarring

February 23, 2015
Stem cells from the dental pulp of wisdom teeth can be coaxed to turn into cells of the eye's cornea and could one day be used to repair corneal scarring due to infection or injury, according to researchers at the University ...

Bio-hybrid dental implant that restores the physiological tooth functions

December 10, 2014
Our bodies function thanks to the smooth integration of different organs within the surrounding tissues. One challenge of creating artificial organs is to mimic the comprehensive organ function. Bio-hybrid implants are the ...

Recommended for you

Hibernating ground squirrels provide clues to new stroke treatments

November 17, 2017
In the fight against brain damage caused by stroke, researchers have turned to an unlikely source of inspiration: hibernating ground squirrels.

Molecular guardian defends cells, organs against excess cholesterol

November 16, 2017
A team of researchers at the Harvard T. H. Chan School of Public Health has illuminated a critical player in cholesterol metabolism that acts as a molecular guardian in cells to help maintain cholesterol levels within a safe, ...

Prototype ear plug sensor could improve monitoring of vital signs

November 16, 2017
Scientists have developed a sensor that fits in the ear, with the aim of monitoring the heart, brain and lungs functions for health and fitness.

Ancient enzyme could boost power of liquid biopsies to detect and profile cancers

November 16, 2017
Scientists are developing a set of medical tests called liquid biopsies that can rapidly detect the presence of cancers, infectious diseases and other conditions from only a small blood sample. Researchers at The University ...

FDA to crack down on risky stem cell offerings

November 16, 2017
U.S. health authorities announced plans Thursday to crack down on doctors pushing stem cell procedures that pose the gravest risks to patients amid an effort to police a burgeoning medical field that previously has received ...

Engineering the gut microbiome with 'good' bacteria may help treat Crohn's disease

November 15, 2017
Penn Medicine researchers have singled out a bacterial enzyme behind an imbalance in the gut microbiome linked to Crohn's disease. The new study, published online this week in Science Translational Medicine, suggests that ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.