Natural reparative capacity of teeth elucidated

April 22, 2015, Institut National de la Sante et de la Recherche Medicale
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

More surprises about blood development—and a possible lead for making lymphocytes

January 22, 2018
Hematopoietic stem cells (HSCs) have long been regarded as the granddaddy of all blood cells. After we are born, these multipotent cells give rise to all our cell lineages: lymphoid, myeloid and erythroid cells. Hematologists ...

How metal scaffolds enhance the bone healing process

January 22, 2018
A new study shows how mechanically optimized constructs known as titanium-mesh scaffolds can optimize bone regeneration. The induction of bone regeneration is of importance when treating large bone defects. As demonstrated ...

Researchers illustrate how muscle growth inhibitor is activated, could aid in treating ALS

January 19, 2018
Researchers at the University of Cincinnati (UC) College of Medicine are part of an international team that has identified how the inactive or latent form of GDF8, a signaling protein also known as myostatin responsible for ...

Bioengineered soft microfibers improve T-cell production

January 18, 2018
T cells play a key role in the body's immune response against pathogens. As a new class of therapeutic approaches, T cells are being harnessed to fight cancer, promising more precise, longer-lasting mitigation than traditional, ...

Weight flux alters molecular profile, study finds

January 17, 2018
The human body undergoes dramatic changes during even short periods of weight gain and loss, according to a study led by researchers at the Stanford University School of Medicine.

Secrets of longevity protein revealed in new study

January 17, 2018
Named after the Greek goddess who spun the thread of life, Klotho proteins play an important role in the regulation of longevity and metabolism. In a recent Yale-led study, researchers revealed the three-dimensional structure ...

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.