Effects of immediate loading directionality on the mechanical sensing protein PIEZO1 expression and early-stage healing process of peri-implant bone.

BACKGROUND: The reduced treatment time of dental implants with immediate loading protocol is an appealing solution for dentists and patients. However, there remains a significant risk of early peri-implant bone response following the placement of immediately loaded implants, and limited information is available regarding loading directions and the associated in vivo characteristics of peri-implant bone during the early stages. This study aimed to investigate the effects of immediate loading directionality on the expression of mechanical sensing protein PIEZO1 and the healing process of peri-implant bone in the early stage. METHODS: Thirty-two implants were inserted into the goat iliac crest models with 10 N static lateral immediate loading applied, followed by histological, histomorphological, immunohistochemical, X-ray microscopy and energy dispersive X-ray spectroscopy evaluations conducted after 10 days. RESULTS: From evaluations at the cellular, tissue, and organ levels, it was observed that the expression of mechanical sensing protein PIEZO1 in peri-implant bone was significantly higher in the compressive side compared to the tensile side. This finding coincided with trends observed in interfacial bone extracellular matrix (ECM) contact percentage, bone mass, and new bone formation. CONCLUSIONS: This study provides a novel insight into the immediate loading directionality as a potential influence factor for dental implant treatments by demonstrating differential effects on the mechanical sensing protein PIEZO1 expression and related early-stage healing processes of peri-implant bone. Immediate loading directions serve as potential therapeutic influence factors for peri-implant bone during its early healing stage.

Upregulated Vanins and their potential contribution to periodontitis.

BACKGROUND: Although Vanins are closely related to neutrophil regulation and response to oxidative stress, and play essential roles in inflammatory diseases with clinical significance, their contribution to periodontitis remains to be determined. This research was designed to assess the expression of Vanins in human gingiva, and to define the relationship between Vanins and periodontitis. METHODS: Forty-eight patients with periodontitis and forty-two periodontal healthy individuals were enrolled for gingival tissue sample collection. Expression levels of VNN1, VNN2 and VNN3 were evaluated by RT-qPCR and validated in datasets GSE10334 and GSE16134. Western blot and immunohistochemistry identified specific proteins within gingiva. The histopathological changes in gingival sections were investigated using HE staining. Correlations between Vanins and clinical parameters, PD and CAL; between Vanins and inflammation, IL1B; and between Vanins and MPO in periodontitis were investigated by Spearman's correlation analysis respectively. Associations between VNN2 and indicators of neutrophil adherence and migration were further validated in two datasets. RESULTS: Vanins were at higher concentrations in diseased gingival tissues in both RT-qPCR and dataset analysis (p < 0.01). Assessment using western blot and immunohistochemistry presented significant upregulations of VNN1 and VNN2 in periodontitis (p < 0.05). The higher expression levels of Vanins, the larger the observed periodontal parameters PD and CAL (p < 0.05), and IL1B (p < 0.001). Moreover, positive correlations existed between VNN2 and MPO, and between VNN2 and neutrophil-related indicators. CONCLUSION: Our study demonstrated upregulation of Vanins in periodontitis and the potential contribution of VNN2 to periodontitis through neutrophils-related pathological processes.

Plumbagin suppresses chronic periodontitis in rats via down-regulation of TNF-α, IL-1ß and IL-6 expression.

Chronic periodontitis (CP) is one of the most common oral diseases, which causes alveolar bone absorption and tooth loss in adults. In this study we aimed to investigate the potential of plumbagin (PL), a widely-investigated active compound extracted from the traditional Chinese herb Plumbago zeylanica L in treating CP. Human periodontal ligament stem cells (PDLSCs) were used for in vitro studies, whereas an animal model of CP was established in SD rats by ligation+Porphyromonas gingivalis (Pg) stimulation. The rats were injected with PL (2, 4, and 6 mg·kg-1·d-1, ip) for 4 weeks. Treatment of PDLSCs with TNF-α (10 ng/mL) markedly stimulated the expression of the proinflammatory cytokines TNF-α, IL-1ß and IL-6, as well as the chemokines CCL-2 and CCL-5, which were dose-dependently suppressed by co-treatment with PL (1.25-5 µmol/L). Furthermore, PL (3.75 µmol/L) markedly suppressed TNF-α-induced activation of the MAPK, NF-κB and JAK/STAT signaling pathways in PDLSCs. In consistence with the in vitro studies, PL administration significantly decreased the expression of TNF-α, IL-1ß and IL-6 in gingiva of the rat with CP, with the dosage 4 mg·kg-1·d-1 showing the best anti-inflammatory effect. Moreover, PL administration decelerated bone destruction in the rat with CP, evidenced by the aveolar bone loss (ABL) and H&E staining results. In conclusion, PL suppresses CP progression in rats by downregulating the expressions of TNF-α, IL-1ß and IL-6 and inhibiting the MAPK, NF-κB and JAK/STAT signaling pathways.

Profiling of bile acids and activated receptor S1PR2 in gingival tissues of periodontitis patients.

BACKGROUND: Bile acids, as a group of cholesterol metabolites, play important roles in inflammation and bone metabolism. However, the possible link between bile acids and periodontitis is still unclear. This study aimed to clarify the alterations of the bile acid profile and corresponding receptor expression levels in periodontitis patients, and evaluate their association with periodontitis severity. METHODS: The concentrations of 15 bile acids in gingival tissues from 16 periodontitis patients and 16 healthy individuals were tested by metabolomics. Sphingosine-1-phosphate receptor 2 (S1PR2) expression was determined by real-time PCR and immunohistochemistry, which was also validated in two datasets, GSE16134 and GSE10334. The correlation between bile acids, S1PR2, and clinical parameters was analyzed by Spearman's correlation analysis, and receiver-operator characteristic (ROC) curves were examined to access the ability of bile acids and S1PR2 for defining local periodontitis status. RESULTS: In the periodontitis group, concentrations of total bile acids were elevated by increases of all bile acid forms, and five conjugated bile acids were significantly increased. Meanwhile, the expression of their receptor, S1PR2, was also upregulated in the periodontitis group. Positive correlations were further observed between glycocholic acid (GCA), taurochenodeoxycholic acid (TCDCA), taurocholic acid (TCA), S1PR2, and periodontal clinical parameters. ROC analysis also showed combinations of two bile acids (GCA and TCDCA) with S1PR2 as novel signatures for indicating local periodontitis status. CONCLUSION: Our findings demonstrated the alterations of the bile acid profile and receptor S1PR2 expression in periodontitis patients, and provided evidence of association between bile acids and periodontitis status.

Mechanobiologically optimized Ti-35Nb-2Ta-3Zr improves load transduction and enhances bone remodeling in tilted dental implant therapy.

The tilted implant with immediate function is increasingly used in clinical dental therapy for edentulous and partially edentulous patients with excessive bone resorption and the anatomic limitations in the alveolar ridge. However, peri-implant cervical bone loss can be caused by the stress shielding effect. Herein, inspired by the concept of "materiobiology", the mechanical characteristics of materials were considered along with bone biology for tilted implant design. In this study, a novel Ti-35Nb-2Ta-3Zr alloy (TNTZ) implant with low elastic modulus, high strength and favorable biocompatibility was developed. Then the human alveolar bone environment was mimicked in goat and finite element (FE) models to investigate the mechanical property and the related peri-implant bone remodeling of TNTZ compared to commonly used Ti-6Al-4V (TC4) in tilted implantation under loading condition. Next, a layer-by-layer quantitative correlation of the FE and X-ray Microscopy (XRM) analysis suggested that the TNTZ implant present better mechanobiological characteristics including improved load transduction and increased bone area in the tilted implantation model compared to TC4 implant, especially in the upper 1/3 region of peri-implant bone that is "lower stress". Finally, combining the static and dynamic parameters of bone, it was further verified that TNTZ enhanced bone remodeling in "lower stress" upper 1/3 region. This study demonstrates that TNTZ is a mechanobiological optimized tilted implant material that enhances load transduction and bone remodeling.

Bis­enoxacin blocks alveolar bone resorption in rats with ovariectomy­induced osteoporosis.

Postmenopausal osteoporosis is a common systemic skeletal disease that is associated with estrogen­deficiency. Bone loss associated with bisphosphonates therapy can increase the risk of developing oral osteonecrosis. Recent studies have indicated that enoxacin may inhibit osteoclast formation and bone resorption via a different mechanism from that of bisphosphonates. Therefore, the authors hypothesized that the use of an enoxacin such as bis­enoxacin (BE) in association with bisphosphonates may be effective in the treatment of postmenopausal osteoporosis­associated alveolar bone resorption and reduce the risk of oral osteonecrosis by allowing the dose of bisphosphonates to be reduced. A total of 30 6­month­old female Sprague­Dawley rats were randomly assigned to five groups: The Sham, Vehicle, zoledronic acid (ZOL), low concentrations of BE (BE­L) and high concentrations of BE (BE­H) groups. The results demonstrated that the ZOL, BE­L and BE­H groups had an increased bone volume/tissue volume, trabecular thickness, mineral apposition rate, mineralizing surface/bone surface and a decreased trabecular separation when compared with the Vehicle group. The microscopic evaluation of histological sections clearly supported the results of the micro­computed tomography. The number of tartrate­resistant acid phosphatase­positive osteoclasts was markedly decreased in the ZOL, BE­L and BE­H groups, indicating that BE may inhibit osteoclast formation. The anti­resorptive effect in the BE­H group was close to or better than that exhibited by the ZOL group; however, this effect was poorer in the BE­L group. In conclusion, BE has the potential to block alveolar bone resorption resulting from ovariectomy­induced osteoporosis in rats in a dose­dependent manner.