Background: Delayed healing of diabetic cutaneous wounds is one of the most common complications of type 2 diabetes mellitus (T2DM), which can bring great distress to patients. In diabetic patients, macrophages accumulate around skin wounds and produce NLRP3 (NOD-, LRR-, and pyrin domain-containing protein 3) inflammasomes, which in turn undergo pyroptosis and produce inflammatory factors such as interleukin-1β that affect wound healing. Although our previous study revealed that apoptotic extracellular vesicles (ApoEVs) produced from mesenchymal stem cells (MSCs) improve cutaneous wound healing in normal C57BL/6 mice, whether ApoEVs can also improve diabetic wound healing remains unclear. Methods: Umbilical cord mesenchymal stem cells (UCMSCs) were cultured in vitro and apoptosis was induced. ApoEVs were extracted and identified and used in a T2DM mouse cutaneous wound model to evaluate the efficacy. The inhibitory effect of ApoEVs on macrophage pyroptosis was verified in vivo and in vitro, and the level of oxidative stress in macrophages was assessed to explore the mechanism by which ApoEVs play a role. Results: UCMSC-derived ApoEVs improved skin defect healing in T2DM mice. Moreover, UCMSC-derived ApoEVs inhibited macrophage pyroptosis in T2DM mice in vivo as well as in vitro under high-glucose culture conditions. In addition, we demonstrated that ApoEVs reduce oxidative stress levels, which is a possible mechanism by which they inhibit macrophage pyroptosis. Conclusions: Our study confirmed that local application of UCMSC-derived ApoEVs improved cutaneous wound healing in T2DM mice. ApoEVs, as products of MSC apoptosis, can inhibit macrophage pyroptosis and regulate the death process by decreasing the level of oxidative stress.

Objectives: To clarify the possible role and mechanism of Cathepsin K (CTSK) in alveolar bone regeneration mediated by jaw bone marrow mesenchymal stem cells (JBMMSC).Materials and Methods: Tooth extraction models of Ctsk knockout mice (Ctsk^‐/‐) and their wildtype (WT) littermates were used to investigate the effect of CTSK on alveolar bone regeneration. The influences of deletion or inhibition of CTSK by odanacatib (ODN) on proliferation and osteogenic differentiation of JBMMSC were assessed by CCK‐8, Western blot and alizarin red staining. To explore the differently expressed genes, RNA from WT and Ctsk^‐/‐ JBMMSC was sent to RNA‐seq. ECAR, glucose consumption and lactate production were measured to identify the effect of Ctsk deficiency or inhibition on glycolysis. At last, we explored whether Ctsk deficiency or inhibition promoted JBMMSC proliferation and osteogenic differentiation through glycolysis.Results: We found out that Ctsk knockout could promote alveolar bone regeneration in vivo. In vitro, we confirmed that both Ctsk knockout and inhibition by ODN could promote proliferation of JBMMSC, up‐regulate expression of Runx2 and ALP, and enhance matrix mineralization. RNA‐seq results showed that coding genes of key enzymes in glycolysis were significantly up‐regulated in Ctsk^‐/‐ JBMMSC, and Ctsk deficiency or inhibition could promote glycolysis in JBMMSC. After blocking glycolysis by 3PO, the effect of Ctsk deficiency or inhibition on JBMMSC’s regeneration was blocked subsequently.Conclusions: Our findings revealed that Ctsk knockout or inhibition could promote alveolar bone regeneration by enhancing JBMMSC regeneration via glycolysis. These results shed new lights on the regulatory mechanism of CTSK on bone regeneration.

Cathepsin K (CTSK) is an important protease responsible for degrading type I collagen, osteopontin, and other bone matrix proteins. The mutations in the CTSK gene can cause pycnodysostosis (OMIM 265800), a rare autosomal recessive bone dysplasia. Patients with pycnodysostosis have been reported to present specific dental abnormalities; however, whether these dental abnormalities are related to dysfunctional CTSK has never been reported. Here we investigated the histologic changes of cementum and alveolar bone in a pycnodysostosis patient, caused by novel compound heterozygous mutations in the CTSK gene (c.87 G>A p.W29X and c.848 A>G p.Y283C). The most impressive manifestations in tooth were extensive periradicular high-density clumps with unclear periodontal space by orthopantomography examination and micro–computed tomography scanning analysis. Hematoxylin/eosin and toluidine blue staining and atomic force microscopy analysis showed that the cementum became significantly thickened, softened, and full of cementocytes. The disorganized bone structure was the main character of alveolar bone. The p.W29X mutation may represent the loss-of-function allele with an earlier termination codon in the precursor CTSK polypeptide. Residue Y283 is highly conserved among papain-like cysteine proteases. Three-dimensional structure modeling analysis found that the loss of the hydroxybenzene residue in the Y283C mutation would interrupt the hydrogen network and possibly affect the self-cleavage of the CTSK enzyme. Furthermore, p.Y283C mutation did not affect the mRNA and protein levels of overexpressed CTSK in COS-7 system but did reduce CTSK enzyme activity. In conclusion, the histologic and ultrastructural changes of cementum and alveolar bone might be affected by CTSK mutation via reduction of its enzyme activity (clinical trial registration: ChiCTR-TNC-10000876).

The treatment of periodontitis can be very challenging due to its complex etiologies. A new pharmacologic strategy entitled “host-modulation therapy,” has been introduced to improve periodontal treatment outcomes. Supposedly, a multifunctional drug with the potential for bacterial infection prevention, host-response modulation and bone healing promotion would be a promising option for periodontitis therapy, but related studies remain substantially lacking. In this study, we successfully conjugated tetracycline with odanacatib (a selective inhibitor of cathepsin K) to construct a multifunctional drug (TC-ODN). We discovered that TC-ODN could promote macrophages polarizing toward anti-inflammatory phenotype and promote osteogenesis of PDLSCs under inflammatory microenvironment. In vivo, TC-ODN could be absorbed and distributed specifically to the bone after systemic administration, and accumulation of TC-ODN increased bone mineral density in ovariectomized rats. Importantly, periodontal administration of TC-ODN could successfully promote bone healing in periodontitis rats with alveolar bone loss. The findings in our study uncovered the excellent biocompatibility and multifunction of TC-ODN, including bone-targeted accumulation, immunoregulation, anti-inflammatory activity and promotion of bone healing, which might contribute to the clinical treatment of periodontitis.

The aim of this study is to investigate risk factors for external root resorption (ERR) of second molars (M2) associated with impacted third molars (M3), and to develop a prediction model that can offer dentists a reliable and efficient tool for predicting the likelihood of ERR. A total of 798 patients with 2156 impacted third molars were collected from three centres between 1 December 2018 and 15 December 2018. ERR was identified by cone beam computed tomography examinations. The effects of different risk factors on the presence/absence of ERR and its severity were analysed using Chi-square or Fisher test. Multivariate logistic regressive analysis with stepwise variable selection methods was performed to identify factors which were significant predictors for ERR and its severity. Subsequently, a prediction model was developed, and the model performance was validated internally and externally. The overall incidence of ERR of second molars was 16.05%. The prediction model was established using six factors including position (upper/lower jaw), impact type, impact depth (PG: A-B-C), contact position, root number of M3, and age. In terms of internal validation, the prediction model demonstrated satisfactory performance, achieving an area under curve of 0.961 and a prediction accuracy of 0.907. As for external validation, the area under curve remained high at 0.953, with a prediction accuracy of 0.892. A risk prediction model for ERR was established in the present study. Position (upper or lower jaw), impact type, impact depth (PG: A-B-C), contact position, root number of M3, and age were identified as influencing variables which were significant predictors in the development of this predictive model. The prediction model showed great discrimination and calibration. This prediction model has the potential to aid dentists and patients in making clinical decisions regarding the necessity of M3 extraction.

To determine the characteristics of anxiety at five different points during tooth extraction, explore the relationship between anxiety and pain, and identify predictors of overall anxiety. A cross-sectional study was conducted among 302 patients undergoing tooth extraction. Anxiety levels were evaluated using a modified dental anxiety scale (MDAS) at five time points: pre-extraction night (T1), hospital waiting period (T2), local anesthesia administration (T3), extraction procedure (T4), and post-extraction (T5). Repeated-measures ANOVA, one-way ANOVA and Pearson correlation analysis were employed to evaluate temporal variations in anxiety levels and their associations with baseline characteristics and pain perception at each assessment point; Chi-square tests and binary logistic regression modeling were used to identify significant predictors of overall anxiety levels. The cohort (mean age 31.3 ± 11.4 years; 60.3% female) demonstrated distinct anxiety patterns throughout the extraction process. Anxiety levels peaked during T3 and T4, followed by a significant post-operative reduction (T5; p < 0.05). Pain (69.5%) and bleeding (67.9%) emerged as the most frequently reported anxiety-inducing factors. Analysis of the correlation between baseline characteristics and anxiety at each time point revealed that younger patients (16–30 years) had smaller anxiety increases during procedures vs. older groups (p = 0.01). Married individuals showed earlier anxiety reduction than unmarried (p = 0.01). Mandibular/bimaxillary extractions and longer durations (> 10 min) correlated with higher intraoperative anxiety (p < 0.05). On the other hand, predicted pain intensity strongly correlated with anxiety at T1–T4 (p < 0.01), while actual pain linked to T4–T5 anxiety (p < 0.01). Postoperative pain showed the strongest association with T5 anxiety (p < 0.001). Risk factor analysis based on overall anxiety levels found that females (OR = 1.76), unemployed individuals (OR = 3.81), and mandibular/bimaxillary extractions (OR = 2.11–2.70) were independent predictors of high overall anxiety. Finally, a prediction model was established. Based on this model, a female unemployed patient with a mandibular third molar had an estimated 72% probability of experiencing anxiety. Dental anxiety peaks during invasive procedural phases and is influenced by demographic, clinical, and pain anticipation. The identified risk factors (female, unemployment, mandibular procedures) highlight targets for preoperative interventions. Addressing pain expectations and optimizing patient communication may mitigate anxiety, particularly in high-risk groups. This study reveals the anxiety characteristics during the perioperative period of tooth extraction. These insights offer essential evidence for clinicians to identify and address anxiety, ultimately enhancing patient care. Additionally, these findings highlight the importance of effective pain control in developing anxiety management strategies in clinical practice. the registration number is ChiCTR2400086891, dated July 15, 2024.