Effects of erythropoietin on osteoblast in the tooth extraction socket in mice periodontitis model

The facilitated osteogenic differentiation by extracellular proline treatment in in vitro cell cultivation using MC3T3E1 and hPDLF

Proline is a major substrate in collagen biosynthesis and is required for collagen molecule formations. However, detailed explanations of the molecular basis through which proline functions in collagen biosynthesis have yet to be provided. Thus, genome-wide screening was employed to elucidate these in the pre-osteoblastic MC3T3-E1 and human periodontal ligament fibroblast (hPDLF) cell lines. Indeed, both cell lines represent important sources for collagen biosynthesis and tissue regeneration in the dental region, specifically treating extracellular proline during cultivations. The altered gene expression patterns were identified, and the precise expression patterns were confirmed by microarray. Cell viability and osteogenic differentiation patterns were examined using a range of experimental methods, such as the MTS assay, ALP staining, ARS staining, and collagen (COL)-type1A ELISA. Overall, we revealed a cell line-specific function of exogenous proline in collagen biosynthesis during osteogenic differentiation conditions with the candidate signaling pathways. These putative signaling networks could represent plausible answers to understanding collagen biosynthesis for regenerating connective tissues such as skin, muscle, and bone.

Proteomic analysis of exosomal proteins associated with bone healing speed in a rat tibial fracture model

This study investigates the impact of exosomes on bone fracture healing in a rat tibial model, distinguishing between fast and slow healing processes. Bone healing and protein expression were assessed through X-ray examinations, hematoxylin and eosin staining, and immunohistochemical staining. Exosomes were isolated, characterized and subjected to liquid chromatography-mass spectrometry for protein analysis. Molecular differences were explored using differentially expressed protein analysis, Kyoto Encyclopedia of Genes and Genomes pathway enrichment and protein-protein interaction networks. Differential bone healing patterns and protein expressions were observed between the control and model groups. Exosomes were successfully isolated and characterized, revealing 2004 identified proteins, including distinct expression profiles. Notably, ribosomal proteins, ferritin and beta-actin emerged as pivotal players in bone fracture healing. This study unveils dynamic changes in bone healing and underscores the role of exosomes in the process. Identified proteins and pathways offer valuable insights for developing innovative therapeutic strategies for bone healing.

Resveratrol facilitates bone formation in high-glucose conditions

Periodontitis is known to be affected by high-glucose conditions, which poses a challenge to periodontal tissue regeneration, particularly in bone formation. In this study, the potential effects of resveratrol (3,5,4'-trihydroxystilbene, RSV) in facilitating bone formation under high-glucose conditions after periodontitis has been investigated. We focused on the analysis of osteoblasts and periodontal ligament cells, which are essential for bone formation including cell proliferation and differentiation. And we aimed to investigate the impact of RSV on bone healing, employed diabetic mouse model induced by streptozotocin and confirmed through histological observation. High-glucose conditions adversely affected cell proliferation and ALP activity in both MC3T3-E1 and hPDLF in vitro, with more significant impact on MC3T3-E1 cells. RSV under high-glucose conditions had positive effects on both, showing early-stage effects for MC3T3-E1 cells and later-stage effects for hPDLF cells. RSV seemed to have a more pronounced rescuing role in MC3T3-E1 cells. Increased ALP activity was observed and the expression levels of significant genes, such as Col 1, TGF-β1, ALP, and OC, in osteogenic differentiation were exhibited stage-specific expression patterns. Upregulated Col 1 and TGF-β1 were detected in the early stage, and then ALP and OC expressions became more pronounced in the later stages. Similarly, stronger positive reactions against RUNX2 were detected in the RSV-treated group compared to the control. Furthermore, in in vivo experiment, RSV stimulates the growth and differentiation of osteoblasts, thereby promoting bone formation. High-glucose levels have the potential to impair cellular functions and the regenerative capacity to facilitate bone formation with MC3T3-E1 rather than hPDLF cells. Resveratrol appears to facilitate the inherent abilities of MC3T3-E1 cells compared with hPDLF cells, indicating its potential capacity to restore functionality during periodontal regeneration.

Effects of Erythropoietin-Promoted Fracture Healing on Bone Turnover Markers in Cats

In orthopaedics, erythropoietin (EPO) is applied in the preoperative management of anaemic patients, but also as a stimulating factor to assist bone regeneration due to its angiogenic and osteoinductive potential. Since orthopaedists mainly rely on their clinical experience to assess bone healing, additional and more objective methods such as studying the dynamics of bone markers are needed. Therefore, the aim of this study was to investigate the plasma activity of bone-specific alkaline phosphatase (BALP), the N-terminal propeptide of type I collagen (PINP), the C-terminal telopeptide of type I collagen (CTX), and deoxypyridinoline (DPD) during the first 2 months of healing of comminuted fractures in cats, either non-stimulated or locally stimulated with recombinant human erythropoietin (rhEPO). The study included twelve cats of mixed breeds, aged 7.2 ± 4 months, weighing 2.11 ± 1.1 kg, with comminuted diaphyseal fractures of the femur. Surgical treatment with plate osteosynthesis was performed in all animals. The cats were randomly divided into two groups-a control (n = 6) and an EPO group (n = 6). The locally applied EPO leads to the increased activity of bone formation markers (BALP and PINP) during the second week after the osteosynthesis, preceding the peaks in the control group by two weeks. The studied bone resorption markers (DPD, CTX) varied insignificantly during the studied period. In conclusion, erythropoietin could serve as a promoter of bone healing in comminuted fractures in cats.

Functional modulation of lysophosphatidic acid type 2 G-protein coupled receptor facilitates alveolar bone formation

Lipid biosynthesis is recently studied its functions in a range of cellular physiology including differentiation and regeneration. However, it still remains to be elucidated in its precise function. To reveal this, we evaluated the roles of lysophosphatidic acid (LPA) signaling in alveolar bone formation using the LPA type 2 receptor (LPAR2) antagonist AMG-35 (Amgen Compound 35) using tooth loss without periodontal disease model which would be caused by trauma and usually requires a dental implant to restore masticatory function. In this study, in vitro cell culture experiments in osteoblasts and periodontal ligament fibroblasts revealed cell type-specific responses, with AMG-35 modulating osteogenic differentiation in osteoblasts in vitro. To confirm the in vivo results, we employed a mouse model of tooth loss without periodontal disease. Five to 10 days after tooth extraction, AMG-35 facilitated bone formation in the tooth root socket as measured by immunohistochemistry for differentiation markers KI67, Osteocalcin, Periostin, RUNX2, transforming growth factor beta 1 (TGF-β1) and SMAD2/3. The increased expression and the localization of these proteins suggest that AMG-35 elicits osteoblast differentiation through TGF-β1 and SMAD2/3 signaling. These results indicate that LPAR2/TGF-β1/SMAD2/3 represents a new signaling pathway in alveolar bone formation and that local application of AMG-35 in traumatic tooth loss can be used to facilitate bone regeneration and healing for further clinical treatment.

Evaluation of Preventive Role of Systemically Applied Erythropoietin after Tooth Extraction in a Bisphosphonate-Induced MRONJ Model

Background and Objectives: In this experimental study, the prophylactic effect of systemically administered erythropoietin (EPO) in medication-related osteonecrosis of the jaw (MRONJ) was evaluated. Materials and Methods: The osteonecrosis model was established using 36 Sprague Dawley rats. EPO was systemically applied before and/or after tooth extraction. Groups were formed based on the application time. All samples were evaluated histologically, histomorphometrically, and immunohistochemically. A statistically significant difference in new bone formation was observed between the groups (p < 0.001). Results: When new bone-formation rates were compared, no significant differences were observed between the control group and the EPO, ZA+PostEPO, and ZA+Pre-PostEPO groups (p = 1, 0.402, and 1, respectively); however, this rate was significantly lower in the ZA+PreEPO group (p = 0.021). No significant differences in new bone formation were observed between the ZA+PostEPO and ZA+PreEPO groups (p = 1); however, this rate was significantly higher in the ZA+Pre-PostEPO group (p = 0.009). The ZA+Pre-PostEPO group demonstrated significantly higher intensity level in VEGF protein expression than the other groups (p < 0.001). Conclusions: Administering EPO two weeks pre-extraction and continuing EPO treatment for three weeks post-extraction in ZA-treated rats optimized the inflammatory reaction, increased angiogenesis by inducing VEGF, and positively affected bone healing. Further studies are needed to determine the exact durations and doses.