RANKL+ senescent cells under mechanical stress: a therapeutic target for orthodontic root resorption using senolytics / 国际口腔科学杂志·英文版

In dentistry, orthodontic root resorption is a long-lasting issue with no effective treatment strategy, and its mechanisms, especially those related to senescent cells, remain largely unknown. Here, we used an orthodontic intrusion tooth movement model with an L-loop in rats to demonstrate that mechanical stress-induced senescent cells aggravate apical root resorption, which was prevented by administering senolytics (a dasatinib and quercetin cocktail). Our results indicated that cementoblasts and periodontal ligament cells underwent cellular senescence (p21+ or p16+) and strongly expressed receptor activator of nuclear factor-kappa B (RANKL) from day three, subsequently inducing tartrate-resistant acid phosphatase (TRAP)-positive odontoclasts and provoking apical root resorption. More p21+ senescent cells expressed RANKL than p16+ senescent cells. We observed only minor changes in the number of RANKL+ non-senescent cells, whereas RANKL+ senescent cells markedly increased from day seven. Intriguingly, we also found cathepsin K+p21+p16+ cells in the root resorption fossa, suggesting senescent odontoclasts. Oral administration of dasatinib and quercetin markedly reduced these senescent cells and TRAP+ cells, eventually alleviating root resorption. Altogether, these results unveil those aberrant stimuli in orthodontic intrusive tooth movement induced RANKL+ early senescent cells, which have a pivotal role in odontoclastogenesis and subsequent root resorption. These findings offer a new therapeutic target to prevent root resorption during orthodontic tooth movement.

[Anesthetic Management of an Infant with a Chromosome 14q Terminal Deletion Syndrome].

We report a case of general anesthesia for male infant with a chromosome 14q terminal deletion syn- drome. In this syndrome, congenital abnormalities such as brain malformations, gastrointestinal and male geni- tourinary abnormalities have been reported as well as some cranio-facial features (micrognathia, dysplastic low-set ears, telecanthus and small mouth, etc.). Gen- eral anesthesia had been performed on him for several times, but his face, presented some typical signs with his growth. At three years of age, we presumed the difficulty in keeping his airway after induction and chose awake intubation with a video laryngoscope and we could perform tracheal intubation. We suggest that the major anesthetic considerations for patients with a chromosome 14q terminal deletion syndrome would be the difficult airway during induc- tion and the respiratory difficulties during perioperative period.