Search

The process of bone regeneration is complicated, and it is still a major clinical challenge to regenerate critical-size bone defects caused by severe trauma, infection, and tumor resection. Intracellular metabolism has been found to play an important role in the cell fate decision of skeletal progenitor cells. GW9508, a potent agonist of the free fatty acid receptors GPR40 and GPR120, appears to have a dual effect of inhibiting osteoclastogenesis and promoting osteogenesis by regulating intracellular metabolism. Hence, in this study, GW9508 was loaded on a scaffold based on biomimetic construction principles to facilitate the bone regeneration process. Through 3D printing and ion crosslinking, hybrid inorganic-organic implantation scaffolds were obtained after integrating 3D-printed β-TCP/CaSiO3 scaffolds with a Col/Alg/HA hydrogel. The 3D-printed β-TCP/CaSiO3 scaffolds had an interconnected porous structure that simulated the porous structure and mineral microenvironment of bone, and the hydrogel network shared similar physicochemical properties with the extracellular matrix. The final osteogenic complex was obtained after GW9508 was loaded into the hybrid inorganic-organic scaffold. To investigate the biological effects of the obtained osteogenic complex, in vitro studies and a rat cranial critical-size bone defect model were utilized. Metabolomics analysis was conducted to explore the preliminary mechanism. The results showed that 50 μM GW9508 facilitated osteogenic differentiation by upregulating osteogenic genes, including Alp, Runx2, Osterix, and Spp1 in vitro. The GW9508-loaded osteogenic complex enhanced osteogenic protein secretion and facilitated new bone formation in vivo. Finally, the results from metabolomics analysis suggested that GW9508 promoted stem cell differentiation and bone formation through multiple intracellular metabolism pathways, including purine and pyrimidine metabolism, amino acid metabolism, glutathione metabolism, and taurine and hypotaurine metabolism. This study provides a new approach to address the challenge of critical-size bone defects. [ABSTRACT FROM AUTHOR]

Osteoporosis is a systemic bone metabolism disorder, which increases the risk of fractures, and in severe cases it may cause disability or even death. An important factor contributing to osteoporosis is the imbalance between bone formation and resorption. Naringin was reported to promote osteoblast differentiation, thus enhancing bone formation and alleviating osteoporosis development. However, the signalling pathways related to the regulatory mechanism of naringin in osteoporosis development are not clear. Proliferation of bone mesenchymal stem cells (BMSCs) treated with naringin in vitro was detected by CCK‐8. An osteogenesis differentiation medium supplemented with naringin was applied to explore the effects of naringin on BMSC osteogenic differentiation, as detected by Alizarin red staining. Ovariectomy (OVX)‐induced postmenopausal osteoporosis (PMOP) rats were orally administered with naringin. Dual‐energy X‐ray absorptiometry (DEXA) and micro‐CT were applied to measure bone mineral density (BMD), bone volume/total volume (BV/TV), trabecula thickness (Tb.Th), trabecula number (Tb.N), trabecular separation (Tb.Sp) and bone surface/bone volume (BS/BV). H&E staining was performed to show pathological changes of the femur in PMOP rats after naringin treatment. Bone metabolism indicators were assessed by ELISA. We found that naringin suppressed the activation of the JAK2/STAT3 pathway. Naringin promoted BMSC proliferation and osteogenic differentiation. Furthermore, naringin alleviates bone loss and improves abnormal bone metabolism of PMOP rats. Collectively, naringin promotes BMSC osteogenic differentiation to ameliorate osteoporosis development by targeting JAK2/STAT3 signalling. [ABSTRACT FROM AUTHOR]

The study investigated the effects of long‐term glucocorticoid (GC) administration on bone remodelling, microstructure, and biomechanical strength in cortical and cancellous (trabecular) bones. Thirty‐one female Sprague–Dawley rats were randomly divided into three dexamethasone (Dex) dosage groups, 1.0, 2.5, and 5.0 mg/kg twice a week for 8 weeks, and one control group treated with saline. At the end of the experiment, the tibia of one side and the fourth lumbar vertebrae were processed into sections for a histomorphometric analysis, while the femur of the same side and the fifth vertebrae were isolated for a biomechanical test. A dose‐dependent decline in bone formation was observed in both trabecular and cortical (periosteal and endosteal) bones. In contrast, bone resorption was inhibited only in cancellous bone in the two higher dose groups and not dose‐related. The ratio of Node/Termini increased, while marrow star volume (MSV) decreased in all Dex groups in metaphyseal trabecular bones, both of which were dose‐dependent. Subendosteal cortex porosity increased in parallel with non‐uniform trabecular distribution, but cortical thickness remained unchanged. Interestingly, there were no significant changes in microstructure or mechanical strength in lumbar trabecular bone. The cortical elastic load was dose‐independently reduced in all three Dex groups when compared with the control group. In summary, bone remodelling was dose‐dependently inhibited in cancellous bones but enhanced in intracortical bones. The non‐uniform distribution of trabecular bone and increased porosity in the inner edge of cortical bone were both in parallel with GC dosage, and the porosity increase was more likely to occur, leading to reduced cortical mechanical strength. [ABSTRACT FROM AUTHOR]

Objective: The conditioned medium of calcined tooth powder (CTP‐CM) is a type of biomimetic mineralized material and well contributing to bone healing and bone formation in vivo. However, little is known about the effect of CTP‐CM on human periodontal ligament stem cells (hPDLSCs) as well as the underlying mechanisms. Methods: ALP activity assay was conducted to select the concentration with the highest ALP level, which was used for the following experiments. Cell proliferation was measured by cell counting kit‐8 assay and flow cytometry analysis. Expression levels of osteogenic markers in CTP‐CM‐induced hPDLSCs were evaluated with real‐time quantitative reverse transcription polymerase chain reaction (qRT‐PCR), immunofluorescence staining, and Western blot. Mineralization of CTP‐CM‐induced hPDLSCs was evaluated by alizarin red staining. Furthermore, the involvement of NF‐κB pathway was examined by immunofluorescence staining and Western blot. Results: 20 μg/ml was selected for the further experiments. Functional studies demonstrated that CTP‐CM exerted almost no influence on the proliferation of hPDLSCs and CTP‐CM increased the osteogenic differentiation of hPDLSCs. Mechanistically, CTP‐CM leads to activation of NF‐κB signaling pathway. When treated with BMS345541, the osteogenic differentiation of CTP‐CM‐treated hPDLSCs was significantly attenuated. Conclusion: CTP‐CM can promote the osteogenic differentiation of hPDLSCs via activating NF‐κB pathway. [ABSTRACT FROM AUTHOR]

With the aging of the population and the extension of life expectancy, osteoporosis is becoming a global epidemic. Although there are several drugs used to treat osteoporosis in clinical practice, such as parathyroid hormone or bisphosphonates, they all have some serious side effects. Therefore, a safer drug is called for osteoporosis, especially for the prevention in the early stage of the disease, not only the treatment in the later stage. Panax notoginseng saponin (PNS), a traditional Chinese herb, has been used as anti-ischemic drug due to its function on improving vascular circulation. In order to verify whether Panax notoginseng saponins (PNS) could be used to prevent osteoporosis, ovariectomy (OVX) was induced in female C57BL/C6J mice, followed by orally administration with 40 mg/kg/d, 80 mg/kg/d, and 160 mg/kg/d of three different dosages of PNS for 9 weeks. Serum biochemical analysis, micro-CT, histological evaluation, and immunostaining of markers of osteogenesis and angiogenesis were performed in the sham, osteoporotic (OVX), and treatment (OVX+PNS) groups. Micro-CT and histological evaluation showed that compared to sham group, the bone mass of OVX group reduced significantly, while it was significantly restored in the moderate-dose PNS (40 mg/kg and 80 mg/kg) treatment groups. The expression of CD31 and osteocalcin (OCN) in the bone tissue of treatment group also increased, suggesting that PNS activated osteogenesis and angiogenesis, which subsequently increased the bone mass. These results confirmed the potential function of PNS on the prevention of osteoporosis. However, in the high dose of PNS (160 mg/kg) group, the antiosteoportic effect had been eliminated, which also suggested the importance of proper dose of PNS for the prevention and treatment of osteoporosis in postmenopausal women. [ABSTRACT FROM AUTHOR]

The aim of the current study was to investigate histopathological changes and bone remodeling in the knee articular cartilage and subchondral bone in rats following treatment with glucocorticoids. A total of 30 3-month-old female Sprague-Dawley rats were randomly divided into either a vehicle control group or one of three experimental groups wherein dexamethasone (Dex) was administered at a dose of 1.0, 2.5 or 5.0 mg/kg (Dex1.0, Dex2.5 and Dex5.0, respectively), for 8 weeks. Articular cartilage and the epiphyseal subchondral bone of the proximal tibias were evaluated by histopathology or for bone remodeling using histomorphometry. No histological changes were identified in the knee articular cartilage but the bone formation rate of the subchondral bone was lower in the Dex1.0 group compared with that of the control group. Compared with the control and the Dex1.0 group, the width of the articular cartilage and the subchondral plate were larger, with abnormal morphology and increased apoptosis of chondrocytes, decreased cell/matrix volume ratio in the cartilage and fewer blood vessels in the subchondral plate in the Dex2.5 and Dex5.0 groups. A higher Dex dose resulted in more severe inhibition of bone formation, a greater number of apoptotic osteocytes and constrained bone resorption. All microstructure parameters indicated no significant changes in the Dex2.5 group but exhibited deterioration in the Dex5.0 group compared with the normal and Dex1.0 group. There were no significant differences in morphological changes, or in static and dynamic bone indices between the Dex2.5 and Dex5.0 groups. In conclusion, long-term glucocorticoid use induced dose-related histopathological changes in the knee articular cartilage, along with unbalanced bone remodeling and osteopenia in the subchondral bone. The degree of damage to the articular cartilage was milder and transformed from compensation to degeneration at higher doses. [ABSTRACT FROM AUTHOR]

Bone defects are challenging to treat in musculoskeletal system due to the lack of vascularization. Biomaterials with internal vascularization ability and osteoinduction bioactivity are promising strategies for orthopedic applications. Vascular endothelial growth factor (VEGF) has been widely used for angiogenesis and osteogenesis. Here, we developed VEGF-loaded PLGA microbubbles (MBs) for improvement of angiogenesis and osteogenesis in bone defect repair in combination with ultrasound-targeted microbubble destruction (UTMD). Release profile showed UTMD promoted the burst release of VEGF from PLGA MBs. We subsequently investigated the combination of ultrasound application with VEGF MBs for in vitro osteogenesis. The results demonstrated that the expression of osteogenesis-related genes and calcium deposits were increased by VEGF MBs in combination of UTMD. Micro-computed tomography (micro-CT) and histological analysis were conducted 4 and 8 weeks post-surgery. In vivo results show that VEGF MBs in combination of UTMD could significantly enhance new bone formation and vascular ingrowth at the defect site in a rat calvarial defect model. In summary, VEGF MBs in combination of UTMD could augment bone regeneration and vascularization at calvarial bone defects and hold huge potential for clinical translation. [ABSTRACT FROM AUTHOR]

Glycerol monolaurate (GML) has the potential of antibacterial and growth-promoting in food. Recent research reported that GML could significantly increase the body index of fish, but whether GML can exert growth-promoting ability via regulating bone metabolism remains unknown. This study explored the effects of GML on the bone growth of fish models and its mechanisms by analyzing the expression of insulin-like growth factor 1(IGF-1). The micro-CT scanning results showed that the dietary supplementation of 750 mg/kg GML significantly increased the body length and bone mineral density, and improved the bone microarchitecture parameters of the caudal vertebrae of zebrafish (Danio rerio). The centrum part of the vertebra was easier to respond to the regulatory effect of GML than the neural arch and the haemal arch. Mechanistically, the content of serum IGF-1, the expression of osteogenic differentiation-related genes, and genes involved in IGF-1/PI3K/Akt signaling pathway were significantly increased. The liver proteomic analysis showed the consistent results that GML supplementation could up-regulate the expression of hepatic IGF-1, and that energy metabolism and growth and development-related metabolic pathways were implicated in the GML bone growth boosting effects. These findings highlight that GML could be used as a functional food additive to improve bone growth and health. [Display omitted] • Glycerol monolaurate (GML) increased body length and bone mineral density of Carassius auratus and Danio rerio. • The phenotype of precaudal and caudal vertebrae in Danio rerio was evaluated using micro-CT. • The expression of insulin-like growth factor 1(IGF-1) and bone metabolism-related genes was increased. • Liver proteomic assays displayed the activation of energy metabolism and growth-related metabolic pathways by GML. • 750 mg/kg GML supplementation effectively improved the bone growth and health of the fish model. [ABSTRACT FROM AUTHOR]

The potential use of osteo-conducive biomaterials in the promotion of bone fracture healing has attracted wide attention. This study investigated if silver nanoparticles (AgNps) could promote the proliferation and osteogenesis of mesenchymal stem cells (MSCs), and improve bone fracture healing. We showed that AgNps promoted MSCs' proliferation and osteogenic differentiation in vitro . Using a mouse femoral facture model, AgNps encapsulated in collagen promoted the formation of fracture callus, and induced early closure of the fracture gap. AgNps may promote the formation of the callus and the subsequent end joining of the fracture bone via multiple routes: (i) chemo-attraction of MSCs and fibroblasts to migrate to the fracture site; (ii) induction of the proliferation of MSCs; (iii) induction of osteogenic differentiation of MSCs via induction/activation of TGF-β/BMP signaling in MSCs. We concluded that AgNps might be beneficial as an adjunct treatment for bone fracture healing clinically. From the Clinical Editor Silver nanoparticles are widely used in wound management in the clinical setting. In this article, the authors demonstrated a novel application in that these nanoparticles were efficient in promoting osteoblastic differentiation in both in-vitro and in-vivo studies. The findings may provide a new treatment direction for bone fracture in the future. [ABSTRACT FROM AUTHOR]

To compare the proliferation and osteogenic differentiation of osteoblasts between newborn rats (1d group) and two-week-old rats (14d group) and to clarify the mechanism underlying these effects. The endogenous expression of osteogenic marker genes was detected by qPCR, including ALP, OCN, Col1a1, and Runx2. The osteoblasts proliferation was evaluated by EdU assay and Western Blotting [PCNA and Cyclin D1]. ALP activities in osteoblasts were detected using a PNPP kit, ALP staining and qPCR. Mineralized nodule formation and intracellular calcium levels were assessed by Alizarin Red staining and calcium colorimetric assay respectively while OCN, Col1a1 and Runx2 levels in osteoblasts were analyzed by immunostaining. Osteogenesis-associated pathways including Wnt/β-Catenin, Akt/PPAR and Smad were analyzed via Western Blotting. Endogenous ALP, OCN, Col1a1, and Runx2 expression levels were significantly higher in osteoblasts from 14d group than those from 1d group. After treatment with osteogenic induction medium, osteoblast proliferation, ALP activity, mineralized nodule formation, and intracellular calcium levels were markedly increased in osteoblasts from 1d group, with similar results also being observed for the expression of OCN, Col1a1, and Runx2. Wnt3a, β-catenin, p-Akt, p-Smad1/5/8, and p-Smad5 protein levels were also higher in osteoblasts from 1d group relative to those from 14d group, while the expression of PPARγ was lower. The superior osteogenic differentiation capacity in osteoblasts was associated with the higher activation levels of Wnt/β-Catenin, Akt/PPAR and Smad signaling pathways, and the enhanced proliferative activity in osteoblasts from 1d group. [ABSTRACT FROM AUTHOR]

[Display omitted] • Propose a preparation method for 3D-printed bioceramics with immunomodulation, angiogenesis, and osteogenesis. • Finding that 3D-printed bioceramics have excellent mineralization properties. • Finding that 3D-printed bioceramic scaffolds can solve implant migration and ectopic osteogenesis of DBM. • 3D-printed bioceramics have excellent biosafety, immunomodulation, angiogenesis, and osteogenesis. Personalized repair of bone defects remains a tremendous clinical challenge. Developing 3D-printed bioceramics with excellent osteogenic potential is an effective therapeutic strategy to overcome this challenge. In this study, we prepared composite bioceramics (designated as CSC-DBM) with immunomodulatory, vascularization, and osteogenesis based on calcium silicate (CS) bioceramics, calcium sulfate (CSH), and decalcified bone matrix (DBM). CSC-DBM bioceramics has an unmatched biomineralization potential due to the synergistic promotion of CS and CSH. Meanwhile, CSC-DBM bioceramics could effectively modulate the immune response, induce M2 macrophage polarization, promote vascular regeneration, and further enhance new bone formation. In summary, this composite bioceramics made of CS bioceramics, CSH, and DBM can provide a new solution for bone defect repair in the clinic. [ABSTRACT FROM AUTHOR]