Osteocalcin: skeletal and extra-skeletal effects

Bioactive deproteinized bovine bone mineral based on self-assembled albumin nanoparticles promoted bone regeneration via activation of Wnt/β-catenin pathway

One of the major problems faced with pre-implant bone reconstruction therapy is that large bone defects do not heal over time. Artificial bone graft materials, such as deproteinized bovine bone mineral, are commonly used in clinics. However, the lack of osteoinductive capacity and risk of post-implantation infections remain key limitations. Bioactive materials with strong bone formation and a high degree of biocompatibility are still needed. In this study, we synthesised bovine serum albumin nanoparticles (BNP) loaded with Tideglusib (TD), TD and BNP were bound together by self-assembly, and mixed with deproteinized bovine bone mineral (DBBM) to form a bone substitute material (TD-BNP@DBBM) that had low cytotoxicity, promoted cell proliferation and migration, induced cell differentiation, and regulated osteogenesis. In vitro, experiments suggested that TD-BNP@DBBM could promote osteoblast differentiation of MC3T3-E1 cells. In vivo, experiments demonstrated that TD-BNP@DBBM significantly accelerated bone reconstruction and enhanced bone healing in a rat cranial defect model. Furthermore, this result suggested a link between the Wnt/β-catenin pathway and the osteogenic effect, providing a basis for subsequent investigations into the mechanism of bone regeneration induced by osteogenic biomaterials. TD-BNP@DBBM might be a promising new approach for treating bone defects.

Re-engineering bone: pathogenesis, diagnosis and emerging therapies for osteoporosis

Osteoporosis, a multifaceted metabolic bone disease, is becoming increasingly prevalent and poses a significant burden on global healthcare systems. Given the limitations of traditional treatments such as pharmacotherapy, tissue engineering has emerged as a promising alternative for osteoporosis management. This review begins by exploring the pathogenesis of osteoporosis, with a focus on the abnormal metabolic, cellular, and molecular signalling microenvironments that drive the disease. We also examine commonly used clinical diagnostic techniques, discussing their strengths and limitations. Notably, this review evaluates various advanced tissue engineering strategies for osteoporosis treatment. Delivery systems, including injectable hydrogels and nanomaterials, are detailed alongside bone tissue engineering materials such as bioactive ceramics, bone cements, and polymers. Additionally, biologically active substances, including exosomes and cytokines, and emerging therapies that leverage small-molecule drugs are explored. Through a comprehensive analysis of the advantages and limitations of current biomaterials and therapeutic approaches, this review provides insights into future directions for tissue engineering-based solutions. By synthesizing current advancements, it aims to inspire innovative perspectives for the clinical management of osteoporosis.

Acute effects of high-intensity interval exercise plus whole-body vibration on bone turnover markers, BDNF, irisin, and neurocognitive performance in postmenopausal women

The acute effects of exercise can elucidate the molecular and psychophysiological mechanisms underlying exercise's benefits in several systems (e.g., the brain, muscle, and bone). In this study, a single 30-minute session of high-intensity interval aerobic exercise (HIIAE) administered in conjunction with isometric resistance exercise on a whole-body vibration (WBV) platform (HIIAE+WBV) was compared with HIIAE alone in their effects on molecular and neurocognitive indices among 63 sedentary, healthy postmenopausal women who were randomly assigned to HIIAE (n = 20), HIIAE+WBV (n = 20), and Control (n = 23) groups. The assessed molecular indices were serum levels of osteocalcin (OC), uncarboxylated OC (ucOC), carboxylated OC (cOC), brain-derived neurotrophic factor (BDNF), and irisin, and the assessed neurocognitive indices were the accuracy rate (AR), reaction time (RT), and electroencephalography event-related potentials (ERPs) of P2 and P3 components in a visuospatial working memory task. Data on these indices before versus after an acute bout of HIIAE or HIIAE+WBV or after a resting session were compared. An HIIAE or HIIAE+WBV intervention yielded no significant change in ERP P2 latency/amplitude and P3 latency but yielded significantly higher ARs, shorter RTs, larger ERP P3 amplitudes, and higher OC, cOC, BDNF, and irisin levels in the postmenopausal women. HIIAE+WBV outperformed HIIAE alone in AR, ucOC, and BDNF. However, the changes in these molecular and neurocognitive indices induced by the two exercise modes did not show any significant correlations in the present study. The present findings suggest that HIIAE and HIIAE+WBV have the potential to acutely influence markers of bone and brain health, with HIIAE+WBV showing greater effectiveness than HIIAE alone. These interventions should be further investigated in future randomized controlled trials involving postmenopausal women.

Impaired MC3T3-E1 osteoblast differentiation triggered by oncogenic HRAS is rescued by the farnesyltransferase inhibitor Tipifarnib

HRAS is a ubiquitously expressed protein and functions as a central regulator of cellular homeostasis. In somatic cells, mutations in this gene cause cancer, while germline mutations trigger a developmental disorder known as Costello syndrome (CS). Among numerous pathologies, adult CS patients develop osteoporosis. Previous studies revealed that HRAS is implicated in bone homeostasis by controlling osteoblast differentiation, adaptation to mechanical strain and repression of RANKL expression in mature osteoblasts, and by regulating osteoclast differentiation. However, the impact of HRAS on osteoblast differentiation is still debatable. In this study, we created stable doxycycline inducible cell lines overexpressing HRAS G12 mutants in MC3T3-E1 preosteoblast cell line and analyzed their impact on osteoblast differentiation. We demonstrated an inhibitory role of HRAS G12S and HRAS G12V mutants on osteogenic differentiation and identified an increased expression of Opn in an HRAS-dependent manner, which directly correlated with impaired osteogenesis, and was rescued by the farnesyl transferase inhibitor Tipifarnib. At the molecular level, Tipifarnib was not able to block HRAS activation, but impaired HRAS localization to the plasma membrane, and inhibited MAPK activation and Opn expression. Thus, HRAS abundance/activation and its potential crosstalk with OPN may be more critical for osteogenic differentiation than previously assumed.

Synergistic Effects of Photobiomodulation and Differentiation Inducers on Osteogenic Differentiation of Adipose-Derived Stem Cells in Three-Dimensional Culture

Osteoporosis, a common metabolic bone disorder, leads to increased fracture risk and significant morbidity, particularly in postmenopausal women and the elderly. Traditional treatments often fail to fully restore bone health and may cause side effects, prompting the exploration of regenerative therapies. Adipose-derived stem cells (ADSCs) offer potential for osteoporosis treatment, but their natural inclination toward adipogenic rather than osteogenic differentiation poses a challenge. This study investigates a novel approach combining differentiation inducers (DIs), three-dimensional (3D) hydrogel scaffolds, and photobiomodulation (PBM) to promote osteogenic differentiation of immortalised ADSCs. A dextran-based 3D hydrogel matrix, supplemented with a DI cocktail of dexamethasone, β-glycerophosphate disodium, and ascorbic acid, was used to foster osteogenesis. PBM was applied using near-infrared (825 nm), green (525 nm), and combined wavelengths at fluences of 3 J/cm2, 5 J/cm2, and 7 J/cm2 to enhance osteogenic potential. Flow cytometry identified osteoblast-specific markers, while inverted light microscopy evaluated cellular morphology. Reactive oxygen species assays measured oxidative stress, and quantitative polymerase chain reaction (qPCR) revealed upregulated gene expression linked to osteogenesis. The findings demonstrate that integrating DIs, 3D hydrogels, and PBM effectively drives osteogenic differentiation in immortalised ADSCs. The PBM enhanced osteogenic marker expression, induced morphological changes, and upregulated gene activity, presenting a promising framework for bone regeneration. Future research should assess the stability and functionality of these differentiated cells and explore their applicability in preclinical models of bone injury or degeneration. This integrative approach demonstrated specific efficacy in promoting the osteogenic differentiation of ADSCs, highlighting its potential application in developing targeted treatments for osteoporosis.

Exploring the In Vitro Effects of Zingerone on Differentiation and Signalling Pathways in Bone Cell Lines

OBJECTIVE

Ensuring adequate bone health is crucial for preventing conditions such as osteoporosis and fractures. Zingerone, a phytonutrient isolated from cooked ginger, has gained attention for its potential benefits in bone health. This study evaluated the osteoprotective potential of zingerone and its effects on differentiation and signalling pathways in vitro using SAOS-2 osteosarcoma and RAW264.7 macrophage cell lines, aiming to elucidate its mechanism of action in bone remodelling.

METHODS

SAOS-2 osteosarcoma and RAW264.7 macrophage cells were treated with zingerone at concentrations of 200 µM. Osteoblast differentiation was assessed by alkaline phosphatase (ALP) activity, bone mineralisation via Alizarin Red S stain, and gene expression markers (ALP, runt-related transcription factor 2 (Runx2), and osteocalcin) via quantitative polymerase chain reaction (q-PCR). Osteoclast differentiation was evaluated by tartrate-resistant acid phosphatase (TRAP) staining, TRAP activity, and mitogen-activated protein kinase (MAPK) pathways.

RESULTS

Treatment with zingerone was non-toxic at 200 µM. Zingerone (200 µM) significantly stimulated the gene expression of ALP and Runx2 in SAOS-2 cells (p < 0.05) without statistically significantly enhancing SAOS-2 mineralisation via calcium deposits. Moreover, zingerone significantly inhibited osteoclast differentiation in RAW264.7 cells as evidenced by reduced TRAP staining and activity (p < 0.05).

CONCLUSIONS

Zingerone shows promise in reducing osteoclast activity and supporting early osteoblast differentiation, suggesting its potential as a dietary supplement for bone health. Further in vivo and clinical studies are needed to confirm its role in managing osteoporosis.

High-throughput bioprinting of spheroids for scalable tissue fabrication

Tissue biofabrication mimicking organ-specific architecture and function requires physiologically-relevant cell densities. Bioprinting using spheroids can achieve this, but is limited due to the lack of practical, scalable techniques. This study presents HITS-Bio (High-throughput Integrated Tissue Fabrication System for Bioprinting), a multiarray bioprinting technique for rapidly positioning multiple spheroids simultaneously using a digitally-controlled nozzle array (DCNA). HITS-Bio achieves an unprecedented speed, ten times faster compared to existing techniques while maintaining high cell viability ( > 90%). The utility of HITS-Bio was exemplified in multiple applications, including intraoperative bioprinting with microRNA transfected human adipose-derived stem cell spheroids for calvarial bone regeneration ( ~ 30 mm3) in a rat model achieving a near-complete defect closure (bone coverage area of ~ 91% in 3 weeks and ~96% in 6 weeks). Additionally, the successful fabrication of scalable cartilage constructs (1 cm3) containing ~600 chondrogenic spheroids highlights its high-throughput efficiency (under 40 min per construct) and potential for repairing volumetric defects.

Emerging role of liver-bone axis in osteoporosis

Background

Increasing attention to liver-bone crosstalk has spurred interest in targeted interventions for various forms of osteoporosis. Liver injury induced by different liver diseases can cause an imbalance in bone metabolism, indicating a novel regulatory paradigm between the liver and bone. However, the role of the liver-bone axis in both primary and secondary osteoporosis remains inadequately elucidated. Therefore, exploring the exact regulatory mechanisms of the liver-bone axis may offer innovative clinical approaches for treating diseases associated with the liver and bone.

Methods

Here, we summarize the latest research on the liver-bone axis by searching the PubMed and Web of Science databases and discuss the possible mechanism of the liver-bone axis in different types of osteoporosis. The literature directly reporting the regulatory role of the liver-bone axis in different types of osteoporosis from the PubMed and Web of Science databases has been included in the discussion of this review (including but not limited to the definition of the liver-bone axis, clinical studies, and basic research). In addition, articles discussing changes in bone metabolism caused by different etiologies of liver injury have also been included in the discussion of this review (including but not limited to clinical studies and basic research).

Results

Several endocrine factors (IGF-1, FGF21, hepcidin, vitamin D, osteocalcin, OPN, LCAT, Fetuin-A, PGs, BMP2/9, IL-1/6/17, and TNF-α) and key genes (SIRT2, ABCB4, ALDH2, TFR2, SPTBN1, ZNF687 and SREBP2) might be involved in the regulation of the liver-bone axis. In addition to the classic metabolic pathways involved in inflammation and oxidative stress, iron metabolism, cholesterol metabolism, lipid metabolism and immunometabolism mediated by the liver-bone axis require more research to elucidate the regulatory mechanisms involved in osteoporosis.

Conclusion

During primary and secondary osteoporosis, the liver-bone axis is responsible for liver and bone homeostasis via several hepatokines and osteokines as well as biochemical signaling. Combining multiomics technology and data mining technology could further advance our understanding of the liver-bone axis, providing new clinical strategies for managing liver and bone-related diseases.The translational potential of this article is as follows: Abnormal metabolism in the liver could seriously affect the metabolic imbalance of bone. This review summarizes the indispensable role of several endocrine factors and biochemical signaling pathways involved in the liver-bone axis and emphasizes the important role of liver metabolic homeostasis in the pathogenesis of osteoporosis, which provides novel potential directions for the prevention, diagnosis, and treatment of liver and bone-related diseases.

Lamc1 promotes osteogenic differentiation and inhibits adipogenic differentiation of bone marrow-derived mesenchymal stem cells

Bone marrow-derived mesenchymal stem cells (BMSCs) exhibit multi-lineage differentiation potential and robust proliferative capacity. The late stage of differentiation signifies the functional maturation and characterization of specific cell lineages, which is crucial for studying lineage-specific differentiation mechanisms. However, the molecular processes governing late-stage BMSC differentiation remain poorly understood. This study aimed to elucidate the key biological processes involved in late-stage BMSC differentiation. Publicly available transcriptomic data from human BMSCs were analyzed after approximately 14 days of osteogenic, adipogenic, and chondrogenic differentiation. Thirty-one differentially expressed genes (DEGs) associated with differentiation were identified. Pathway enrichment analysis indicated that the DEGs were involved in extracellular matrix (ECM)-receptor interactions, focal adhesion, and glycolipid biosynthesis, a ganglion series process. Subsequently, the target genes were validated using publicly available single-cell RNA-seq data from mouse BMSCs. Lamc1 exhibited predominant distribution in adipocytes and osteoblasts, primarily during the G2/M phase. Tln2 and Hexb were expressed in chondroblasts, osteoblasts, and adipocytes, while St3gal5 was abundantly distributed in stem cells. Cell communication analysis identified two receptors that interact with LAMCI. q-PCR results confirmed the upregulation of Lamc1, Tln2, Hexb, and St3gal5 during osteogenic differentiation and their downregulation during adipogenic differentiation. Knockdown of Lamc1 inhibited adipogenic and osteogenic differentiation. In conclusion, this study identified four genes, Lamc1, Tln2, Hexb, and St3gal5, that may play important roles in the late-stage differentiation of BMSCs. It elucidated their interactions and the pathways they influence, providing a foundation for further research on BMSC differentiation.

Ti3C2Tx@PLGA/Icaritin microspheres-modified PLGA/β-TCP scaffolds modulate Icaritin release to enhance bone regeneration through near-infrared response

Porous poly (lactic-co-glycolic acid)/β-tricalcium phosphate/Icaritin (PLGA/β-TCP/ICT, PTI) scaffold is a tissue engineering scaffold based on PLGA/β-TCP (PT) containing Icaritin, the main active ingredient of the Chinese medicine Epimedium. Due to its excellent mechanical properties and osteogenic effect, PTI scaffold has the potential to promote bone defect repair. However, the release of ICT from the scaffolds is difficult to control. In this study, we constructed Ti3C2Tx@PLGA/ICT microspheres (TIM) and evaluated their characterization as well as ICT release under near-infrared (NIR) irradiation. We utilized TIM to modify the PT scaffold and performed biological experiments. First, we cultured rat bone marrow mesenchymal stem cells on the scaffold to assess biocompatibility and osteogenic potential under on-demand NIR irradiation. Subsequently, to evaluate the osteogenic properties of TIM-modified scaffoldin vivo, the scaffold was implanted into a femoral condyle defect model. TIM have excellent drug-loading capacity and encapsulation efficiency for ICT, and the incorporation of Ti3C2Txendows TIM with photothermal conversion capability. Under 0.90 W cm-2NIR irradiation, the temperature of TIM maintained at 42.0 ± 0.5 °C and the release of ICT was accelerated. Furthermore, while retaining its original properties, the TIM-modified scaffold was biocompatible and could promote cell proliferation, osteogenic differentiation, and biomineralizationin vitro, as well as the osteogenesis and osseointegrationin vivo, and its effect was further enhanced through the modulation of ICT release under NIR irradiation. In summary, TIM-modified scaffold has the potential to be applied in bone defects repairing.

Advancing bone regeneration: Unveiling the potential of 3D cell models in the evaluation of bone regenerative materials

Bone, a rigid yet regenerative tissue, has garnered extensive attention for its impressive healing abilities. Despite advancements in understanding bone repair and creating treatments for bone injuries, handling nonunions and large defects remains a major challenge in orthopedics. The rise of bone regenerative materials is transforming the approach to bone repair, offering innovative solutions for nonunions and significant defects, and thus reshaping orthopedic care. Evaluating these materials effectively is key to advancing bone tissue regeneration, especially in difficult healing scenarios, making it a critical research area. Traditional evaluation methods, including two-dimensional cell models and animal models, have limitations in predicting accurately. This has led to exploring alternative methods, like 3D cell models, which provide fresh perspectives for assessing bone materials' regenerative potential. This paper discusses various techniques for constructing 3D cell models, their pros and cons, and crucial factors to consider when using these models to evaluate bone regenerative materials. We also highlight the significance of 3D cell models in the in vitro assessments of these materials, discuss their current drawbacks and limitations, and suggest future research directions. STATEMENT OF SIGNIFICANCE: This work addresses the challenge of evaluating bone regenerative materials (BRMs) crucial for bone tissue engineering. It explores the emerging role of 3D cell models as superior alternatives to traditional methods for assessing these materials. By dissecting the construction, key factors of evaluating, advantages, limitations, and practical considerations of 3D cell models, the paper elucidates their significance in overcoming current evaluation method shortcomings. It highlights how these models offer a more physiologically relevant and ethically preferable platform for the precise assessment of BRMs. This contribution is particularly significant for "Acta Biomaterialia" readership, as it not only synthesizes current knowledge but also propels the discourse forward in the search for advanced solutions in bone tissue engineering and regeneration.

Diagnostic and Prognostic Value of Indicators of Bone Metabolism Markers in Patients Following Mandibulectomy and Free Fibula Flap Reconstruction with Endosteal Implants

Purpose

To evaluate and assess the indicators of bone metabolism markers osteocalcin and β-Cross-Laps in blood serum as a tool for monitoring bone regeneration and determining the time of implantation in patients after mandibulectomy and reconstruction of a free fibular flap with subsequent endosteal implants.

Materials and Methods

Forty-eight patients in a 6-year period participated in this study, due to resection for tumors. All patients underwent reconstruction with fibula free flap after tumor resection, 4-6 months after osteoectomy, dental implants were installed with further orthopedic rehabilitation. To assess the rate of bone remodeling after transplantation, the content biochemical markers of bone remodeling osteocalcin and β-Cross-Laps serum were determined by enzyme immunoassay.

Results

All 46 fibular free flaps were healed without complications and were survived. A total 326 implants installed, 8 implants failed to osseointegrate, and 6 implants failed after 5 years of loading (peri-implantitis). Success rate of implants after 5 years was 95,7%. In patients before surgery, the mean of osteocalcin levels was 8.5 ng/ml, two months later, there was a sharp increase in the content of osteocalcin by 15.4 ng/ml, after four months reached 24.7 ng/ml, after six months of 28.6 ng/ml, then the indicator began to decrease and after 12 months it was approaching the norm of 14.7 ng/ml. In patients before surgery, the mean level of β-Cross-Laps was 0.76 ng/ml, after two months bone transplantation the mean level of β-Cross-Laps decreased to - 0.65 ng/ml, after four months the indicator increased and reached of 0.98 ng/ml, after six months the indicator was - 1.56 ng/ml, then these indicators began to decrease and after 12 months, approaching normal values of - 0.87 ng/ml. There is a correlation between different concentrations of osteocalcin or β-Cross- Laps and the success rate of implants. Implants were shown to be unsuccessful low concentrations of osteocalcin and high concentrations of β-Cross-Laps in serum.

Conclusion

Studies have shown that the long-term survival and success rates of implants placed in the reconstructed areas may guarantee an excellent prognosis of implant-supported prostheses. Bone markers in blood serum osteocalcin and β-Cross-Laps can be used to evaluate the rate of bone remodeling, which allows you to determine the time of implantation.

Protein absorption on titanium surfaces treated with a high-power laser: A systematic review

STATEMENT OF PROBLEM

The surface of titanium dental implants treated with a high-power laser has been reported to favor osseointegration, mainly by altering protein uptake. Despite the large number of articles that address the topic, the heterogeneity of methodologies and results makes an understanding of the treatment's benefits difficult, and a systematic review is needed.

PURPOSE

The purpose of this systematic review was to further the knowledge on protein uptake on titanium surfaces that have undergone treatment with a high-power laser.

MATERIAL AND METHODS

This review followed the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines and was registered with the Open Science Framework (OSF) (osf.io/gcbna). Searches were performed in PubMed, Scopus, Web of Science, Embase, and Google Scholar databases. The articles were selected in 2 steps by 2 independent reviewers according to the previously selected eligibility criteria. The risk of bias was analyzed by using the Joanna Briggs Institute (JBI)-adapted quasi-experimental study evaluation tool.

RESULTS

The studies addressed have shown that applying a high-power laser to the implant surface, depending on its settings, generates topographical changes that can optimize the protein absorption process and thus accelerate the other biological processes.

CONCLUSIONS

The studies identified in this systematic review showed that surface treatment with a high-power laser represents a promising technique with a positive influence on protein uptake and osseointegration.

A radiographic and histological study to compare red (650 nm) versus near infrared (810 nm) diode lasers photobiomodulation for alveolar socket preservation

Previous findings indicated that the laser photobiomodulation is more effective than the control or placebo in preserving the alveolar socket. This study aimed to compare two different lasers regarding their effectiveness in aiding alveolar socket preservation. Twenty extraction sockets were selected then divided into two equal groups. Group A was exposed to 650 nm Diode laser, and Group B to 810 nm Diode laser following the same protocol and parameters after a standard alveolar socket preservation procedure with collagen plug. Radiographic analysis with cone beam computed tomography was done to compare the alveolar bone surface area immediately after extraction and three months post-operatively, while bone samples collected before implant drilling were histologically examined for newly formed bone evaluation and histomorphometric analysis in terms of percentage of new bone surface area, percentage of unmineralized bone and finally, immunohistochemical analysis of Osteocalcin reaction surface area as well as optical density. Radiographically, infrared (810 nm) Diode effect on alveolar bone surface area has significantly exceeded the red laser, while histologically, red (650 nm) Diode has demonstrated statistical significance regarding all parameters; newly formed bone surface area percentage, unmineralized bone area percentage and finally Osteocalcin bone marker reaction surface area percentage and optical density. Under the specified conditions and laser parameters, photobiomodulation using the 810 nm Diode got the upper hand radiographically, yet histologically, the red 650 nm Diode managed to dominate all histological parameters when both employed as an adjunct to alveolar socket preservation procedures.

Bioactive Self-Regulated Liquified Microcompartments to Bioengineer Bone-Like Microtissues

Designing a microenvironment that drives autonomous stromal cell differentiation toward osteogenesis while recapitulating the complexity of bone tissue remains challenging. In the current study, bone-like microtissues are created using electrohydrodynamic atomization to form two distinct liquefied microcapsules (mCAPs): i) hydroxypyridinone (HOPO)-modified gelatin (GH mCAPs, 7.5% w/v), and ii) HOPO-modified gelatin and dopamine-modified gelatin (GH+GD mCAPs, 7.5%+1.5% w/v). The ability of HOPO to coordinate with iron ions at physiological pH allows the formation of a semipermeable micro-hydrogel shell. In turn, the dopamine affinity for calcium ions sets a bioactive milieu for bone-like microtissues. After 21 days post encapsulation, GH and GH+GD mCAPs potentiate autonomous osteogenic differentiation of mesenchymal stem cells accompanied by collagen type-I gene upregulation, increased alkaline phosphatase (ALP) expression, and formation of mineralized extracellular matrix. However, the GH+GD mCAPs show higher levels of osteogenic markers starting on day 14, translating into a more advanced and organized mineralized matrix. The GH+GD system also shows upregulation of the receptor activator of nuclear factor kappa-B ligand (RANK-L) gene, enabling the autonomous osteoclastic differentiation of monocytes. These catechol-based mCAPs offer a promising approach to designing multifunctional and autonomous bone-like microtissues to study in vitro bone-related processes at the cell-tissue interface, angiogenesis, and osteoclastogenesis.

Physiological cell bioprinting density in human bone-derived cell-laden scaffolds enhances matrix mineralization rate and stiffness under dynamic loading

Human organotypic bone models are an emerging technology that replicate bone physiology and mechanobiology for comprehensive in vitro experimentation over prolonged periods of time. Recently, we introduced a mineralized bone model based on 3D bioprinted cell-laden alginate-gelatin-graphene oxide hydrogels cultured under dynamic loading using commercially available human mesenchymal stem cells. In the present study, we created cell-laden scaffolds from primary human osteoblasts isolated from surgical waste material and investigated the effects of a previously reported optimal cell printing density (5 × 106 cells/mL bioink) vs. a higher physiological cell density (10 × 106 cells/mL bioink). We studied mineral formation, scaffold stiffness, and cell morphology over a 10-week period to determine culture conditions for primary human bone cells in this microenvironment. For analysis, the human bone-derived cell-laden scaffolds underwent multiscale assessment at specific timepoints. High cell viability was observed in both groups after bioprinting (>90%) and after 2 weeks of daily mechanical loading (>85%). Bioprinting at a higher cell density resulted in faster mineral formation rates, higher mineral densities and remarkably a 10-fold increase in stiffness compared to a modest 2-fold increase in the lower printing density group. In addition, physiological cell bioprinting densities positively impacted cell spreading and formation of dendritic interconnections. We conclude that our methodology of processing patient-specific human bone cells, subsequent biofabrication and dynamic culturing reliably affords mineralized cell-laden scaffolds. In the future, in vitro systems based on patient-derived cells could be applied to study the individual phenotype of bone disorders such as osteogenesis imperfecta and aid clinical decision making.

Regulation of Immune Inflammation and Promotion of Periodontal Bone Regeneration by Irisin-Loaded Bioactive Glass Nanoparticles

Clinical solutions of bone defects caused by periodontitis involve surgical treatment and subsequent anti-infection treatment using antibiotics. Such a strategy faces a key challenge in that the excessive host immune response results in the damage of periodontal tissues. Consequently, it is of great importance to develop novel periodontitis treatment that allows the regulation of the host immune response and promotes the generation of periodontal tissues. Irisin has a good bone regeneration ability and could reduce the inflammatory reaction by regulating the differentiation of macrophages. In this study, we loaded irisin onto bioactive glass nanoparticles (BGNs) to prepare a composite, irisin-BGNs (IR-BGNs) with anti-inflammatory, bacteriostatic, and tissue regeneration functions, providing a novel idea for the design of ideal materials for repairing oral tissue defects caused by periodontitis. We also verified that the IR-BGNs had better anti-inflammatory properties on RAW264.7 cells compared to irisin and BGNs alone. Strikingly, when hPDLCs were stimulated with IR-BGNs, they exhibited increased expression of markers linked to osteogenesis, ALP activity, and mineralization ability in comparison to the negative control. Furthermore, on the basis of RNA sequencing results, we validated that the p38 pathway can contribute to the osteogenic differentiation of the IR-BGNs. This work may offer new thoughts on the design of ideal materials for repairing oral tissue defects.

Assessment of Biochemical Bone Turnover Markers in Polish Healthy Children and Adolescents

BACKGROUND

Assessing bone turnover in paediatric populations is crucial for understanding the physiological changes occurring during skeletal development and identifying potential abnormalities. The objective of this study was to assess osteocalcin (OC), bone alkaline phosphatase (BALP), and C-terminal telopeptide of type I collagen (CTX-I) levels reflecting bone formation and resorption for age and sex in Polish healthy children and adolescents.

MATERIALS AND METHODS

A total of 355 healthy normal-weight children and adolescents (46.5% girls) aged 1-18 years old were recruited. Total body less head (TBLH) and spine L1-L4 were used in children to assess bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA). Bone marker concentrations were determined by immunoenzymatic methods.

RESULTS

Bone marker levels in girls and boys started with higher values in the first year of life and subsequently decreased until reaching a nadir during the prepubertal period. The pubertal peak values of bone markers were reached at 11-13 years old in boys and at 9-11 years old in girls. After puberty, the adolescents showed a gradual decline in bone marker concentrations to the values observed in adults. We found positive correlations between OC level and TBLH-BMD (r = 0.329, p = 0.002), TBLH-BMD Z-score (r = 0.245, p = 0.023), and L1-L4 BMD (r = 0.280, p = 0.009) in the prepubertal group.

CONCLUSIONS

We showed serum levels of bone turnover markers-BALP, OC, and CTX-I-in relation to age and sex in healthy Polish children and adolescents. The age intervals of these markers for girls and boys aged 1-18 years old may be clinically useful in the assessment of bone metabolism in individuals with skeletal disorders.

Osteocalcin: Promoter or Inhibitor of Hydroxyapatite Growth?

Osteocalcin is the most abundant noncollagenous bone protein and the functions in bone remineralization as well as in inhibition of bone growth have remained unclear. In this contribution, we explain the dual role of osteocalcin in the nucleation of new calcium phosphate during bone remodeling and in the inhibition of hydroxyapatite crystal growth at the molecular scale. The mechanism was derived using pH-resolved all-atom models for the protein, phosphate species, and hydroxyapatite, along with molecular dynamics simulations and experimental and clinical observations. Osteocalcin binds to (hkl) hydroxyapatite surfaces through multiple residues, identified in this work, and the fingerprint of binding residues varies as a function of the (hkl) crystal facet and pH value. On balance, the affinity of osteocalcin to hydroxyapatite slows down crystal growth. The unique tricalcium γ-carboxylglutamic acid (Gla) domain hereby rarely adsorbs to hydroxyapatite surfaces and faces instead toward the solution. The Gla domain enables prenucleation of calcium phosphate for new bone formation at a slightly acidic pH of 5. The growth of prenucleation clusters of calcium phosphate continues upon increase in pH value from 5 to 7 and is much less favorable, or not observed, on the native osteocalcin structure at and above neutral pH values of 7. The results provide mechanistic insight into the early stages of bone remodeling from the molecular scale, help inform mutations of osteocalcin to modify binding to apatites, support drug design, and guide toward potential cures for osteoporosis and hyperosteogeny.

The Therapeutic Potential of Two Egyptian Plant Extracts for Mitigating Dexamethasone-Induced Osteoporosis in Rats: Nrf2/HO-1 and RANK/RANKL/OPG Signals

The prolonged use of exogenous glucocorticoids, such as dexamethasone (Dex), is the most prevalent secondary cause of osteoporosis, known as glucocorticoid-induced osteoporosis (GIO). The current study examined the preventative and synergistic effect of aqueous chicory extract (ACE) and ethanolic purslane extract (EPE) on GIO compared with Alendronate (ALN). The phytochemical contents, elemental analysis, antioxidant scavenging activity, and ACE and EPE combination index were evaluated. Rats were randomly divided into control, ACE, EPE, and ACE/EPE MIX groups (100 mg/kg orally), Dex group (received 1.5 mg Dex/kg, Sc), and four treated groups received ACE, EPE, ACE/EPE MIX, and ALN with Dex. The bone mineral density and content, bone index, growth, turnover, and oxidative stress were measured. The molecular analysis of RANK/RANKL/OPG and Nrf2/HO-1 pathways were also evaluated. Dex causes osteoporosis by increasing oxidative stress, decreasing antioxidant markers, reducing bone growth markers (OPG and OCN), and increasing bone turnover and resorption markers (NFATc1, RANKL, ACP, ALP, IL-6, and TNF-α). In contrast, ACE, EPE, and ACE/EPE MIX showed a prophylactic effect against Dex-induced osteoporosis by modulating the measured parameters and the histopathological architecture. In conclusion, ACE/EPE MIX exerts a powerful synergistic effect against GIO by a mode of action different from ALN.

ENPP1 ameliorates vascular calcification via inhibiting the osteogenic transformation of VSMCs and generating PPi

This study aims to investigate the impact of ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) on vascular calcification in rats. The rationale behind studying ENPP1's role in vascular calcification lies in its potential to modulate calcification processes. Understanding this relationship can offer insights into novel therapeutic avenues for addressing vascular calcification-related disorders. In this experiment, vascular smooth muscle cell (VSMC) calcification was induced using β-glycerophosphoric acid. Subsequently, recombinant AAV9-carrying ENPP1 was introduced into VSMCs to achieve both in vitro and in vivo overexpression of ENPP1. The findings indicate that ENPP1 overexpression significantly reduces calcium and phosphorus content in the aorta (P < 0.05). Alizarin red and von Kossa staining reveal notable reductions in calcium salt deposits in VSMCs and aorta, respectively. Notably, the expression levels of BMP-2, PINP, OC, and BALP were substantially decreased in VSMCs (P < 0.05), underscoring ENPP1's role in impeding osteoblast-like transdifferentiation of VSMCs. Additionally, ENPP1 overexpression led to a significant increase in pyrophosphate (PPi) levels compared to control rats (P < 0.05). In conclusion, this study suggests that ENPP1 contributes to alleviating vascular calcification by elevating PPi levels and inhibiting the phenotypic transformation of VSMCs. These findings shed light on the potential therapeutic role of ENPP1 in mitigating vascular calcification-related complications.

Mechanical properties, and in vitro biocompatibility assessment of biomimetic dual layered keratin/ hydroxyapatite scaffolds

A novel biomimetic dual layered keratin/hydroxyapatite (keratin/HA) scaffold was designed using iterative freeze-drying technique. The prepared scaffolds were studied using several analytical techniques to better understand the biological, structural, and mechanical properties. The developed multilayered, interconnected, porous keratin scaffold with different hydroxyapatite (HA) content in the outer and inner layer, mimics the inherent gradient structure of alveolar bone. SEM studies showed an interconnected porous architecture of the prepared scaffolds with seamless integration between the upper and lower layers. The incorporation of HA improved the mechanical properties keratin/HA scaffolds. The keratin/HA scaffolds exhibited superior mechanical properties in terms of Young's modulus and compressive strength in comparison to pure keratin scaffolds. The biocompatibility studies suggested that both keratin and keratin/HA scaffolds were cyto-compatible, in terms of cell proliferation. Furthermore, it showed that both the tested materials can served as an ideal substrate for the differentiation of Saos-2 cells, leading to mineralization of the extracellular matrix. In summary, ionic liquid based green technique was employed for keratin extraction to fabricate keratin/HA scaffolds and our detailed in vitro investigations suggest the great potential for these composite scaffolds for bone tissue engineering in future.

Bone Mineral Density and the Risk of Parkinson's Disease in Postmenopausal Women

BACKGROUND

Whether bone mineral density (BMD) is related to the risk of Parkinson's disease (PD) is unclear.

OBJECTIVES

The objective of this study was to examine the association between BMD status and incident PD in postmenopausal women.

METHODS

We retrospectively examined a nationwide cohort of 272,604 women aged 66 years who participated in the 2009-2012 Korean national health screening for transitional ages. BMD was evaluated using dual-energy X-ray absorptiometry of the central bones. The use of antiosteoporosis medications (AOMs) was assessed. We performed multivariable Cox proportional hazards regression to evaluate the association between BMD and PD risk by calculating hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

During the median follow-up of 7.7 years, 2,884 (1.1%) incident PD cases developed. After adjusting for confounding factors, lower BMD was associated with an increased risk of PD (P for trend <0.001). Individuals with osteoporosis had a 1.40-fold higher HR (1.40, 95% CI: 1.25-1.56) than those with a normal BMD. Sensitivity analyses suggested the associations robust to longer lag periods and further adjustment. These associations were prominent in individuals without AOM use before or after enrollment (P for interaction = 0.031 and 0.014). Increased risks of PD in individuals with osteopenia and osteoporosis who did not use AOMs were attenuated by the medication use during the follow-up period, regardless of previous AOM use.

CONCLUSIONS

Lower postmenopausal BMD and osteoporosis were associated with an increased risk of PD. In addition, this association could be mitigated using AOMs. Proper management of BMD in postmenopausal women may help prevent PD. © 2023 International Parkinson and Movement Disorder Society.

Healthy eating index and bone health markers in adults with metabolically healthy and unhealthy obese phenotypes

Background

The Healthy Eating Index (HEI) estimates the diet quality, and low HEI scores are associated with adverse bone outcomes. However, the relationship between HEI scores and bone health in individuals who are obese but otherwise healthy or obese with comorbidities remains unclear.

Objective

We aimed to evaluate the association of HEI scores with bone mineral density (BMD), bone regulating hormones and bone turnover markers in individuals with metabolically healthy obese (MHO) and metabolically unhealthy obese (MUO) phenotypes.

Methods

This was a cross-sectional analysis of 122 adults who were overweight or obese. A questionnaire was completed to obtain demographic data. Body composition and BMD were assessed by a Dual Energy X-Ray Absorptiometry (DXA) exam. The HEI scores and dietary components were calculated using a 24-h dietary recall. Blood samples were collected for the analysis of serum 25-hydroxyvitamin D (s25OHD), total osteocalcin (OC), parathyroid hormone (PTH), and C-terminal telopeptide (CTx) concentrations. The MHO and MUO phenotypes were classified according to the absence or presence of metabolic abnormalities.

Results

The sample mean age was 37.91 ± 12.66 years, 50.8% were men, mean body mass index (BMI) was 30.01 ± 4.63 kg/m2, and 45.9% were classified as the MUO phenotype. The mean HEI scores were 54.42 ± 16.25 and 61.48% had low-diet quality. HEI scores were positively associated with s25OHD in the MUO phenotype group (β = 0.194, 95%CI = 0.038-0.350, p = 0.016). Certain dietary score components, such as fruits, seafood and plant protein, added sugars, whole grains, and fatty acids were also associated with bone health markers. However, HEI scores were not associated with BMD measures, neither with other bone regulating hormones and turnover markers.

Conclusion

There was a positive association between HEI scores and s25OHD in adults who were overweight or obese with MUO phenotype. Additionally, the adequate consumption of specific food groups may benefit bone mass and metabolism. These results emphasize the importance of lifestyle interventions encouraging healthy eating habits to prevent s25OHD deficiency, poor bone health, and cardiometabolic complications.

β-TCP/S53P4 Scaffolds Obtained by Gel Casting: Synthesis, Properties, and Biomedical Applications

The objective of this study was to investigate the osteogenic and antimicrobial effect of bioactive glass S53P4 incorporated into β-tricalcium phosphate (β-TCP) scaffolds in vitro and the bone neoformation in vivo. β-TCP and β-TCP/S53P4 scaffolds were prepared by the gel casting method. Samples were morphologically and physically characterized through X-ray diffraction (XRD) and scanning electron microscope (SEM). In vitro tests were performed using MG63 cells. American Type Culture Collection reference strains were used to determine the scaffold's antimicrobial potential. Defects were created in the tibia of New Zealand rabbits and filled with experimental scaffolds. The incorporation of S53P4 bioglass promotes significant changes in the crystalline phases formed and in the morphology of the surface of the scaffolds. The β-TCP/S53P4 scaffolds did not demonstrate an in vitro cytotoxic effect, presented similar alkaline phosphatase activity, and induced a significantly higher protein amount when compared to β-TCP. The expression of Itg β1 in the β-TCP scaffold was higher than in the β-TCP/S53P4, and there was higher expression of Col-1 in the β-TCP/S53P4 group. Higher bone formation and antimicrobial activity were observed in the β-TCP/S53P4 group. The results confirm the osteogenic capacity of β-TCP ceramics and suggest that, after bioactive glass S53P4 incorporation, it can prevent microbial infections, demonstrating to be an excellent biomaterial for application in bone tissue engineering.

Diosmin mitigates dexamethasone-induced osteoporosis in vivo: Role of Runx2, RANKL/OPG, and oxidative stress

Secondary osteoporosis is commonly caused by long-term intake of glucocorticoids (GCs), such as dexamethasone (DEX). Diosmin, a natural substance with potent antioxidant and anti-inflammatory properties, is clinically used for treating some vascular disorders. The current work targeted exploring the protective properties of diosmin to counteract DEX-induced osteoporosis in vivo. Rats were administered DEX (7 mg/kg) once weekly for 5 weeks, and in the second week, vehicle or diosmin (50 or 100 mg/kg/day) for the next four weeks. Femur bone tissues were collected and processed for histological and biochemical examinations. The study findings showed that diosmin alleviated the histological bone impairments caused by DEX. In addition, diosmin upregulated the expression of Runt-related transcription factor 2 (Runx2) and phosphorylated protein kinase B (p-AKT) and the mRNA transcripts of Wingless (Wnt) and osteocalcin. Furthermore, diosmin counteracted the rise in the mRNA levels of receptor activator of nuclear factor-kB ligand (RANKL) and the reduction in osteoprotegerin (OPG), both were induced by DEX. Diosmin restored the oxidant/antioxidant equilibrium and exerted significant antiapoptotic activity. The aforementioned effects were more pronounced at the dose level of 100 mg/kg. Collectively, diosmin has proven to protect rats against DEX-induced osteoporosis by augmenting osteoblast and bone development while hindering osteoclast and bone resorption. Our findings could be used as a stand for recommending supplementation of diosmin for patients chronically using GCs.

In Vitro Screening Studies on Eight Commercial Essential Oils-Derived Compounds to Identify Promising Natural Agents for the Prevention of Osteoporosis

Over the years, essential oils (EOs) and their compounds have gained growing interest due to their anti-inflammatory, antimicrobial, antioxidant, and immunomodulatory properties. The aim of this study was to evaluate the effect of eight commercially available EO-derived compounds ((R)-(+)-limonene, (S)-(−)-limonene, sabinene, carvacrol, thymol, alpha-pinene (α-pinene), beta-pinene (β-pinene), and cinnamaldehyde) on the bone formation process in vitro to select the most promising natural agents that could potentially be used in the prevention or treatment of osteoporosis. Within this study, evaluation of cytotoxicity, cell proliferation, and osteogenic differentiation was performed with the use of mouse primary calvarial preosteoblasts (MC3T3-E1). Moreover, extracellular matrix (ECM) mineralization was determined using MC3T3-E1 cells and dog adipose tissue-derived mesenchymal stem cells (ADSCs). The two highest non-toxic concentrations of each of the compounds were selected and used for testing other activities. The conducted study showed that cinnamaldehyde, thymol, and (R)-(+)-limonene significantly stimulated cell proliferation. In the case of cinnamaldehyde, the doubling time (DT) for MC3T3-E1 cells was significantly shortened to approx. 27 h compared to the control cells (DT = 38 h). In turn, cinnamaldehyde, carvacrol, (R)-(+)-limonene, (S)-(−)-limonene, sabinene, and α-pinene exhibited positive effects on either the synthesis of bone ECM or/and mineral deposition in ECM of the cells. Based on the conducted research, it can be assumed that cinnamaldehyde and (R)-(+)-limonene are the most promising among all tested EO-derived compounds and can be selected for further detailed research in order to confirm their biomedical potential in the chemoprevention or treatment of osteoporosis since they not only accelerated the proliferation of preosteoblasts, but also significantly enhanced osteocalcin (OC) synthesis by preosteoblasts (the OC level was approx. 1100–1200 ng/mg compared to approx. 650 ng/mg in control cells) and ECM calcification of both preosteoblasts and mesenchymal stem cells. Importantly, cinnamaldehyde treatment led to a three-fold increase in the mineral deposition in ADSCs, whereas (R)-(+)-limonene caused a two-fold increase in the ECM mineralization of both MC3T3-E1 cells and ADSCs.

Determinants of bone mass in older adults with normal- and overweight derived from the crosstalk with muscle and adipose tissue

Lower bone mass in older adults may be mediated by the endocrine crosstalk between muscle, adipose tissue and bone. In 150 community-dwelling adults (59-86 years, BMI 17-37 kg/m²; 58.7% female), skeletal muscle mass index, adipose tissue and fat mass index (FMI) were determined. Levels of myokines, adipokines, osteokines, inflammation markers and insulin were measured as potential determinants of bone mineral content (BMC) and density (BMD). FMI was negatively associated with BMC and BMD after adjustment for mechanical loading effects of body weight (r-values between -0.37 and -0.71, all p < 0.05). Higher FMI was associated with higher leptin levels in both sexes, with higher hsCRP in women and with lower adiponectin levels in men. In addition to weight and FMI, sclerostin, osteocalcin, leptin × sex and adiponectin were independent predictors of BMC in a stepwise multiple regression analysis. Muscle mass, but not myokines, showed positive correlations with bone parameters that were weakened after adjusting for body weight (r-values between 0.27 and 0.58, all p < 0.01). Whereas the anabolic effect of muscle mass on bone in older adults may be partly explained by mechanical loading, the adverse effect of obesity on bone is possibly mediated by low-grade inflammation, higher leptin and lower adiponectin levels.

Low-intensity pulsed ultrasound enhances immunomodulation and facilitates osteogenesis of human periodontal ligament stem cells by inhibiting the NF-κB pathway

Human periodontal ligament stem cells (hPDLSCs) are vital in cellular regeneration and tissue repair due to their multilineage differentiation potential. Low intensity pulsed ultrasound (LIPUS) has been applied for treating bone and cartilage defects. This study explored the role of LIPUS in the immunomodulation and osteogenesis of hPDLSCs. hPDLSCs were cultured in vitro, and the effect of different intensities of LIPUS (30, 60, and 90 mW/cm²) on hPDLSC viability was measured. hPDLSCs irradiated by LIPUS and stimulated by lipopolysaccharide (LPS) and LIPUS (90 mW/cm2) were co-cultured with peripheral blood mononuclear cells (PBMCs). Levels of immunomodulatory factors in hPDLSCs and inflammatory factors in PBMCs were estimated, along with determination of osteogenesis-related gene expression in LIPUS-irradiated hPDLSCs. The mineralized nodules and alkaline phosphatase (ALP) activity of hPDLSCs and levels of IκBα, p-IκBα, and p65 subunits of NF-κB were determined. hPDLSC viability was increased as LIPUS intensity increased. Immunomodulatory factors were elevated in LIPUS-irradiated hPDLSCs, and inflammatory factors were reduced in PBMCs. Osteogenesis-related genes, mineralized nodules, and ALP activity were promoted in LIPUS-irradiated hPDLSCs. The cytoplasm of hPDLSCs showed increased IκBα and p65 and decreased p-IκBα at increased LIPUS intensity. After LPS and LIPUS treatment, the inhibitory effect of LIPUS irradiation on the NF-κB pathway was partially reversed, and the immunoregulation and osteogenic differentiation of hPDLSCs were decreased. LIPUS irradiation enhanced immunomodulation and osteogenic differentiation abilities of hPDLSCs by inhibiting the NF-κB pathway, and the effect is dose-dependent. This study may offer novel insights relevant to periodontal tissue engineering.

Bone Turnover Markers and Osteokines in Adolescent Female Athletes of High- and Low-Impact Sports Compared With Nonathletic Controls

This study examined differences in resting concentrations of markers of bone formation and resorption, and osteokines between female adolescent (12-16 y) swimmers, soccer players, and nonathletic controls. Resting, morning blood samples were obtained after an overnight fast from 20 swimmers, 20 soccer players, and 20 nonathletic controls, matched for age. carboxyl-terminal cross-linking telopeptide of type I collagen (CTX), amino-terminal propeptide of type I collagen (P1NP), total osteocalcin (OC), sclerostin, osteoprotegerin (OPG), and receptor activator of nuclear factor kappa B ligand (RANKL) were analyzed in serum. After controlling for percent body fat, there were no significant differences between swimmers and nonathletic controls in any of the measured markers. In contrast, soccer players had significantly higher P1NP (89.5 [25.6] ng·mL-1), OC (57.6 [22.9] ng·mL-1), and OPG (1052.5 [612.6] pg·mL-1) compared with both swimmers (P1NP: 66.5 [20.9] ng·mL-1; OC: 24.9 [12.5] ng·mL-1; OPG: 275.2 [83.8] pg·mL-1) and controls (P1NP: 58.5 [16.2] ng·mL-1; OC: 23.2 [11.9] ng·mL-1; OPG: 265.4 [97.6] pg·mL-1), with no differences in CTX, sclerostin, and RANKL. These results suggest that bone formation is higher in adolescent females engaged in high-impact sports like soccer compared with swimmers and controls.

Combined vitamin D and magnesium supplementation does not influence markers of bone turnover or glycemic control: A randomized controlled clinical trial

High-dose vitamin D supplementation can increase total osteocalcin concentrations that may reduce insulin resistance in individuals at risk for prediabetes or diabetes mellitus. Magnesium is a cofactor in vitamin D metabolism and activation. The purpose of this study was to determine the combined effect of vitamin D and magnesium supplementation on total osteocalcin concentrations, glycemic indices, and other bone turnover markers after a 12-week intervention in individuals who were overweight and obese, but otherwise healthy. We hypothesized that combined supplementation would improve serum total osteocalcin concentrations and glycemic indices more than vitamin D supplementation alone or a placebo. A total of 78 women and men completed this intervention in 3 groups: a vitamin D and magnesium group (1000 IU vitamin D3 and 360 mg magnesium glycinate), a vitamin D group (1000 IU vitamin D3), and a placebo group. Despite a significant increase in serum 25-hydroxyvitamin D concentrations in the vitamin D and magnesium group compared with the placebo group (difference = 5.63; CI, -10.0 to -1.21; P = .001) post-intervention, there were no differences in serum concentrations of total osteocalcin, glucose, insulin, and adiponectin or the homeostatic model assessment of insulin resistance (HOMA-IR) among groups (P > .05 for all). Additionally, total osteocalcin (β = -0.310, P = .081), bone-specific alkaline phosphatase (β = 0.004, P = .986), and C-terminal cross-linked telopeptide (β = 0.426, P = .057), were not significant predictors of HOMA-IR after the intervention. Combined supplementation was not associated with short-term improvements in glycemic indices or bone turnover markers in participants who were overweight and obese in our study. This trial was registered at clinicaltrials.gov (NCT03134417).

A Systematic Review of the Circadian Rhythm of Bone Markers in Blood

There exists a marked circadian variation for several bone markers (BM), which is influenced by endogenous as well as exogenous factors including hormones, physical activity, and fasting. Consequently, was the aim of this review to provide an overview of the knowledge of the circadian variation of BM and which factors influence this rhythmicity. A systematic search of PubMed was performed for studies evaluating the circadian variation of BM and which factors influence this rhythmicity. The studies were screened for eligibility by a set of predetermined criteria including a list of relevant BM and a minimum study duration of 24 h with at least 3 blood samples of which two should be at least 6 h apart. In total were 29 papers included. There exists a marked circadian variation for most BM including Carboxy-terminal Cross-Linked Telopeptide of Type I Collagen (CTX) and osteocalcin (OC) with nighttime or early morning peak. Pro-collagen Type I N-terminal Propeptide (PINP) and PTH also showed circadian rhythm but with less amplitude. The inter-osteoblast-osteoclast regulatory markers such as OPG, RANKL, FGF23, and sclerostin showed no circadian rhythm. The markers were differently affected by exogenous factors like fasting, which greatly reduced the circadian variation of CTX but did not affect PINP or OC. The marked circadian variation and the factors which influence the rhythmicity, e.g., fasting are of great consequence when measuring BM. To reduce variation and heighten validity should circadian variation and fasting be kept in mind when measuring BM.

Healthy plant-based diet index as a determinant of bone mineral density in osteoporotic postmenopausal women: A case-control study

Introduction

The association between plant-based diet indices and bone mineral density (BMD) of women with osteoporosis have not been studied in Iranian women. This study aimed to evaluate the association between plant-based diet indices and BMD in postmenopausal women with osteopenia/osteoporosis.

Materials and methods

The present research was a case-control study conducted on 131 postmenopausal women with osteoporosis/osteopenia and 131 healthy women. The BMD of the femoral neck and lumbar vertebrae was measured by the Dual-energy X-ray absorptiometry (DXEA) method. Participants were asked to complete a validated semi-quantitative food frequency questionnaire (FFQ). We used three versions of plant-based diet indices, including plant-based diet index (PDI), healthy plant-based diet index (hPDI), and unhealthy plant-based diet index (uPDI). Two different multivariable logistic regression was used for the crude and adjusted model to assess the relationship between PDI, hPDI, and uPDI with odds of femoral and lumbar BMD.

Results

There was a reverse association between last tertile of hPDI with femoral BMD abnormality in the both adjusted model [Model 1: odds ratio (OR): 0.33; 95% confidence interval (CI): 0.19-0.63 and Model 2: OR: 0.30; 95% CI: 0.15-0.58, respectively]. Furthermore, we found a reverse relationship between hPDI with lumbar BMD abnormality in the first adjusted model (OR: 0.36; 95% CI: 0.19-0.67). On the other hand, a negative association was observed in the second and last tertile of hPDI with lumbar BMD abnormality (OR: 0.47; 95% CI: 0.24-0.90 and OR: 0.34; 95% CI: 0.17-0.64, respectively). According to the results, the association of femoral BMD abnormality in the last tertile of uPDI compared to the first tertile in the both adjusted models (Model 1: OR: 2.85; 95% CI: 1.52-5.36 and Model 2: OR: 2.63; 95% CI: 1.37-5.06) were significant. Also, we observed a positive relationship between the last tertile of uPDI with lumbar BMD abnormality compared to the lowest tertile in the both adjusted models (Model 1; OR: 4.16; 95% CI: 2.20-7.85, Model 2; OR: 4.23; 95% CI: 2.19-8.19).

Conclusion

Overall, the findings indicated that in postmenopausal women with osteoporosis, a healthy plant-based diet could prevent bone loss, and an unhealthy plant-based diet might have detrimental effects on BMD.

Recent advances in the crosstalk between adipose, muscle and bone tissues in fish

Control of tissue metabolism and growth involves interactions between organs, tissues, and cell types, mediated by cytokines or direct communication through cellular exchanges. Indeed, over the past decades, many peptides produced by adipose tissue, skeletal muscle and bone named adipokines, myokines and osteokines respectively, have been identified in mammals playing key roles in organ/tissue development and function. Some of them are released into the circulation acting as classical hormones, but they can also act locally showing autocrine/paracrine effects. In recent years, some of these cytokines have been identified in fish models of biomedical or agronomic interest. In this review, we will present their state of the art focusing on local actions and inter-tissue effects. Adipokines reported in fish adipocytes include adiponectin and leptin among others. We will focus on their structure characteristics, gene expression, receptors, and effects, in the adipose tissue itself, mainly regulating cell differentiation and metabolism, but in muscle and bone as target tissues too. Moreover, lipid metabolites, named lipokines, can also act as signaling molecules regulating metabolic homeostasis. Regarding myokines, the best documented in fish are myostatin and the insulin-like growth factors. This review summarizes their characteristics at a molecular level, and describes both, autocrine effects and interactions with adipose tissue and bone. Nonetheless, our understanding of the functions and mechanisms of action of many of these cytokines is still largely incomplete in fish, especially concerning osteokines (i.e., osteocalcin), whose potential cross talking roles remain to be elucidated. Furthermore, by using selective breeding or genetic tools, the formation of a specific tissue can be altered, highlighting the consequences on other tissues, and allowing the identification of communication signals. The specific effects of identified cytokines validated through in vitro models or in vivo trials will be described. Moreover, future scientific fronts (i.e., exosomes) and tools (i.e., co-cultures, organoids) for a better understanding of inter-organ crosstalk in fish will also be presented. As a final consideration, further identification of molecules involved in inter-tissue communication will open new avenues of knowledge in the control of fish homeostasis, as well as possible strategies to be applied in aquaculture or biomedicine.

Load carriage aerobic exercise stimulates a transient rise in biochemical markers of bone formation and resorption

Exercise can be both anabolic and catabolic for bone tissue. The temporal response of both bone formation and resorption following an acute bout of exercise is not well described. We assayed biochemical markers of bone and calcium metabolism for up to 3 days after military-relevant exercise. In randomized order, male (n = 18) and female (n = 2) Soldiers (means ± SD; 21.2 ± 4.1 years) performed a 60-min bout of load carriage (30% body mass; 22.4 ± 3.7 kg) treadmill exercise (EXER) or a resting control trial (REST). Blood samples were collected following provision of a standardized breakfast before (PRE), after (POST) exercise/rest, 1 h, 2 h, and 4 h into recovery. Fasted samples were also collected at 0630 on EXER and REST and for the next three mornings after EXER. Parathyroid hormone and phosphorus were elevated (208% and 128% of PRE, respectively, P < 0.05), and ionized calcium reduced (88% of PRE, P < 0.05) after EXER. N-terminal propeptide of type 1 collagen was elevated at POST (111% of PRE, P < 0.05), and the resorption marker, C-terminal propeptide of type 1 collagen was elevated at 1 h (153% of PRE, P < 0.05). Osteocalcin was higher than PRE at 1 through 4 h post EXER (119%-120% of PRE, P < 0.05). Sclerostin and Dickkopf-related protein-1 were elevated only at POST (132% and 121% of PRE, respectively, P < 0.05) during EXER. Trivial changes in biomarkers during successive recovery days were observed. These results suggest that 60 min of load carriage exercise elicits transient increases in bone formation and resorption that return to pre-exercise concentrations within 24 h post-exercise.NEW & NOTEWORTHY In this study, we demonstrated evidence for increases in both bone formation and resorption in the first 4 h after a bout of load carriage exercise. However, these changes largely disappear by 24 h after exercise. Acute formation and resorption of bone following exercise may reflect distinct physiological mechanoadaptive responses. Future work is needed to identify ways to promote acute post-exercise bone formation and minimize post-exercise resorption to optimize bone adaptation to exercise.

Graphene Oxide-Modified Concentric Microgrooved Titanium Surfaces for the Dual Effects of Osteogenesis and Antiosteoclastogenesis

Surface modification is an effective method to resolve the biocompatibility, mechanical, and functional issues of various titanium implant materials. Therefore, many researchers have modified the implant surface to promote the osseointegration of the implant and improve the implant survival rate. In this study, we used photolithography to construct concentric microgrooves with widths of 10 μm and depths of 10 μm, to produce an osteon-mimetic concentric microgrooved titanium surface that was further modified with graphene oxide by silanization (GO-CMS). The modified surface had great biocompatibility and promoted the proliferation of bone marrow-derived mesenchymal stem cells (BMSCs) and RAW264.7 macrophages. The concentric microgrooves on the titanium surface guided cell migration, altered actin cytoskeleton, and caused the cells to arrange in concentric circles. The titanium surface of the GO-modified osteon-mimetic concentric microgrooves promoted the osteogenic differentiation of BMSCs and inhibited the osteoclastogenic differentiation of RAW264.7 cells. Subsequently, we constructed an indirect coculture system and found that RAW264.7 cells cultured on a GO-CMS material surface in a BMSC-conditioned medium (BCM) decreased receptor activator of nuclear factor-κB ligand (RANKL) secretion and increased OPG secretion and also that the BCM inhibited osteoclastogenic differentiation. Additionally, the secretion of OSM increased in BMSCs cultured in RAW264.7-conditioned medium (RCM) in the GO-CMS group, which in turn promoted the osteogenic differentiation of BMSCs. In conclusion, the titanium surface of GO-modified osteon-mimetic concentric microgrooves had dual effects of osteogenesis and antiosteoclastogenesis under single and coculture conditions, which is beneficial for implant osseointegration and is a promising method for the future direction of surface modifications of implants.

Risk factors for fracture in patients with fibrous dysplasia of the proximal femur

OBJECTIVE

The primary aim of this retrospective observational clinical study was to explore the risk factors for fracture in patients with fibrous dysplasia (FD) of the proximal femur.

METHODS

We investigated body mass index, bilateral radiographs on both sides, femoral neck shaft angle measurements, and markers of bone metabolism in patients with FD of the proximal femur according to whether or not they had sustained a hip fracture. Nine clinical parameters (age, sex, clinical classification, anatomic classification, femoral neck shaft angle, and procollagen type 1 N-terminal propeptide, C-terminal telopeptide of type I collagen, and osteocalcin levels) were selected for univariate analysis. Factors that were significant in univariate analysis were then subjected to multivariate logistic analysis.

RESULTS

Clinical classification, anatomic classification, femoral neck shaft angle, and the osteocalcin level were identified to be statistically significant risk factors for fracture in univariate analysis. Anatomic classification, femoral neck shaft angle, and the osteocalcin level remained significant risk factors in multivariate analysis.

CONCLUSIONS

Anatomic classification, femoral neck shaft angle, and the osteocalcin level are important risk factors for fracture in patients with FD of the proximal femur and could be used to guide implementation of a fracture prevention strategy in these patients.

Mesoporous Silica Promotes Osteogenesis of Human Adipose-Derived Stem Cells Identified by a High-Throughput Microfluidic Chip Assay

Silicon-derived biomaterials are conducive to regulating the fate of osteo-related stem cells, while their effects on the osteogenic differentiation of human adipose-derived stem cells (hADSCs) remain inconclusive. Mesoporous silica (mSiO₂) is synthesized in a facile route that exhibited the capability of promoting osteogenic differentiation of hADSCs. The metabolism of SiO₂ in cells is proposed according to the colocalization fluorescence analysis between lysosomes and nanoparticles. The released silicon elements promote osteogenic differentiation. The detection of secretory proteins through numerous parallel experiments performed via a microfluidic chip confirms the positive effect of SiO₂ on the osteogenic differentiation of hADSCs. Moreover, constructed with superparamagnetic iron oxide (Fe₃O₄), the magnetic nanoparticles (MNPs) of Fe₃O₄@mSiO₂ endow the cells with magnetic resonance imaging (MRI) properties. The MNP-regulated osteogenic differentiation of autologous adipose-derived stem cells provides considerable clinical application prospects for stem cell therapy of bone tissue repair with an effective reduction in immune rejection.

Marine plankton exoskeletone-derived hydroxyapatite/polycaprolactone composite 3D scaffold for bone tissue engineering

3D porous scaffolds based on biodegradable polymers are one of the materials for bone tissue regeneration. In this study, a porous scaffold was prepared using a solvent casting/particulate leaching method that used polycaprolactone (PCL) and hydroxyapatite (OceanBone-HAp) extracted from a marine plankton exoskeleton to achieve excellent bone regeneration. In this study, the morphology and physicochemical properties of the PCL/OceanBone-HAp scaffolds were evaluated using scanning electron microscopy, X-ray diffraction, and porosity analysis. The results confirmed the porous structure of the scaffold and removal of the solvent and porogen particles. In vitro test results revealed superior cell adhesion, proliferation, and viability of PCL/OceanBone-HAp scaffolds compared to PCL scaffolds alone. The enhanced alkaline phosphatase activity and expression of bone morphogenetic protein 2, collagen type I α 1, osteocalcin, and bone sialoprotein in the PCL/OceanBone-HAp scaffolds were confirmed through ALP and real-time polymerase chain reaction assays. Moreover, in vivo experiments using a rabbit calvarial defect model showed that the PCL/OceanBone-HAp scaffold exhibited enhanced bone regeneration compared to the PCL scaffold. Therefore, the PCL/OceanBone-HAp scaffold is a promising scaffold for bone repair.

Galangin induces the osteogenic differentiation of human amniotic mesenchymal stem cells via the JAK2/STAT3 signaling pathway

The regulation of stem cell directional differentiation is a core research topic in regenerative medicine, and modulating the fate of stem cells is a promising strategy for precise intervention through the utilization of naturally small molecule compounds. The present study aimed to explore the potential pro-osteogenic differentiation effect of galangin, a flavonoid derived from Alpinia officinarum, on human amniotic mesenchymal stem cells (hAMSCs) and the underlying molecular mechanism. The results showed that galangin had no cytotoxicity towards hAMSCs when the concentration was less than 50 μM. Treatment with 10 μM galangin significantly increased alkaline phosphatase (ALP) secretion and calcium deposition in hAMSCs. Meanwhile, galangin upregulated the mRNA and protein expression of early osteoblast-specific markers, namely ALP, RUNX2, and OSX, and late osteoblast-specific markers, CoL1α1, OPN, and OCN, in hAMSCs. Furthermore, signaling pathway screening studies showed that galangin enhanced the phosphorylation of Janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3). In addition, molecular docking results suggest there is a promising interaction between galangin and JAK2. Finally, treatment with the JAK2 specific inhibitor AG490 effectively reversed the induction of osteogenic differentiation, upregulation of osteoblast-specific marker expression, and activation of JAK2/STAT3 signaling induced by galangin. These results show that galangin induces the osteogenic differentiation of hAMSCs through the JAK2/STAT3 signaling pathway and could serve as a promising small molecular osteoinducer for application to hAMSCs in regenerative medicine.

Multifunctional TiO2 coatings developed by plasma electrolytic oxidation technique on a Ti20Nb20Zr4Ta alloy for dental applications

A newly developed β-Ti alloy based on the Ti-Nb-Zr-Ta system (Ti20Nb20Zr4Ta) has been subjected to Plasma Electrolytic Oxidation (PEO) treatment to obtain a multifunctional ceramic-like (TiO₂) coating with superior tribocorrosion (wear and corrosion) resistance and improved biocompatibility. For this aim, elements such as Ca, P, and Ag NPs have been incorporated into the oxide film to obtain bioactive and biocide properties. The chemical composition and morphology of the TiO₂-PEO coating was characterized, and its multifunctionality was addressed by several means, including antibacterial activity assessment, formation of bone-like apatite, metallic ion release evaluation, in vitro cellular response analysis, and corrosion and tribocorrosion tests in artificial saliva. The developed coatings enhanced the corrosion and tribocorrosion resistance of the bare alloy and exhibited antibacterial ability with low cytotoxicity and negligible ion release. Furthermore, they were able to sustain MC3T3-E1 preosteoblast viability/proliferation and osteogenic differentiation. Altogether, the results obtained demonstrate the potential of the TiO₂ coating incorporating Ca, P, and Ag NPs to be used for dental applications.

Activation of aldehyde dehydrogenase 2 protects ethanol-induced osteonecrosis of the femoral head in rat model

OBJECTIVES

Osteonecrosis of the femoral head (ONFH) is a devastating disease characterized by destructive bone structures, enlarged adipocyte accumulation and impaired vascularization. The aldehyde dehydrogenase 2 (ALDH 2) is the limiting enzyme for ethanol metabolism with many physiological functions. The aim was investigated the potential protective role of activated ALDH 2 by Alda-1 for ethanol-induced ONFH.

MATERIALS AND METHODS

The ethanol-induced ONFH in rat was performed to explore the protective of Alda-1 by various experimental methods. Subsequently, the effect of Alda-1 and ethanol on the osteogenic and adipogenic differentiation was investigated via multiple cellular and molecular methods. Finally, the effect of Alda-1 and ethanol on the neo-vascularization was detected in Human umbilical vein endothelial cells (HUVECs) and ONFH model.

RESULTS

Firstly, radiographical and pathological measurements indicated that alda-1 protected ethanol-induced ONFH. Moreover, ethanol significantly inhibited the proliferation and osteogenic differentiation of BMSCs, whereas Alda-1 could distinctly rescue it by PI3K/AKT signalling. Secondly, ethanol remarkably promoted the lipid vacuoles formation of BMSCs, while Alda-1 significantly retarded it on BMSCs by AMPK signalling pathway. Finally, ethanol significantly inhibited proliferation and growth factor level resulting in reduced angiogenesis, whereas Alda-1 could rescue the effect of ethanol. Additionally, Alda-1 significantly reduced the occurrence of ONFH and promoted vessel number and distribution in alcoholic ONFH.

CONCLUSIONS

Alda-1 activation of ALDH 2 was highly demonstrated to protect ethanol-induced ONFH by triggering new bone formation, reducing adipogenesis and stimulating vascularization.

Early Life Exposure to a Diet With a Supramolecular Lipid Structure Close to That of Mammalian Milk Improves Early Life Growth, Skeletal Development, and Later Life Neurocognitive Function in Individually and Socially Housed Male C57BL/6J Mice

Breastfeeding (duration) can be positively associated with infant growth outcomes as well as improved cognitive functions during childhood and later life stages. (Prolonged) exposure to optimal lipid quantity and quality, i.e., the supramolecular structure of lipids, in mammalian milk, may contribute to these beneficial effects through nutritional early-life programming. In this pre-clinical study, we exposed male C57BL/6J mice from post-natal Days 16 to 42 (i.e., directly following normal lactation), to a diet with large lipid droplets coated with bovine milk fat globule membrane-derived phospholipids, which mimic more closely the supramolecular structure of lipid droplets in mammalian milk. We investigated whether exposure to this diet could affect growth and brain development-related parameters. As these outcomes are also known to be affected by the post-weaning social environment in mice, we included both individually housed and pair-wise housed animals and studied whether effects of diet were modulated by the social environment. After Day 42, all the animals were fed standard semi-synthetic rodent diet. Growth and body composition were assessed, and the mice were subjected to various behavioral tests. Individual housing attenuated adolescent growth, reduced femur length, and increased body fat mass. Adult social interest was increased due to individual housing, while cognitive and behavioral alterations as a result of different housing conditions were modest. The diet increased adolescent growth and femur length, increased lean body mass, reduced adolescent anxiety, and improved adult cognitive performance. These effects of diet exposure were comparable between individually and socially housed mice. Hence, early life exposure to a diet with lipid droplets that mimic the supramolecular structure of those in mammalian milk may improve adolescent growth and alters brain function in both socially and individually housed mice. These findings suggest that lipid structure in infant milk formula may be a relevant target for nutritional solutions, targeting both healthy infants and infants facing growth challenges.

Dysregulation of Wnt signaling in bone of type 2 diabetes mellitus and diabetic Charcot arthropathy

Background

Type 2 diabetes mellitus (T2DM) patients show a markedly higher fracture risk and impaired fracture healing when compared to non-diabetic patients. However in contrast to type 1 diabetes mellitus, bone mineral density in T2DM is known to be normal or even regionally elevated, also known as diabetic bone disease. Charcot arthropathy is a severe and challenging complication leading to bone destruction and mutilating bone deformities. Wnt signaling is involved in increasing bone mineral density, bone homeostasis and apoptotic processes. It has been shown that type 2 diabetes mellitus is strongly associated with gene variants of the Wnt signaling pathway, specifically polymorphisms of TCF7L2 (transcription factor 7 like 2), which is an effector transcription factor of this pathway.

Methods

Bone samples of 19 T2DM patients and 7 T2DM patients with additional Charcot arthropathy were compared to 19 non-diabetic controls. qPCR analysis for selected members of the Wnt-signaling pathway (WNT3A, WNT5A, catenin beta, TCF7L2) and bone gamma-carboxyglutamate (BGLAP, Osteocalcin) was performed and analyzed using the 2-ΔΔCt- Method. Statistical analysis comprised one-way analysis of variance (ANOVA).

Results

In T2DM patients who had developed Charcot arthropathy WNT3A and WNT5A gene expression was down-regulated by 89 and 58% compared to healthy controls (p < 0.0001). TCF7L2 gene expression showed a significant reduction by 63% (p < 0.0001) and 18% (p = 0.0136) in diabetic Charcot arthropathy. In all diabetic patients BGLAP (Osteocalcin) was significantly decreased by at least 59% (p = 0.0019).

Conclusions

For the first time with this study downregulation of members of the Wnt-signaling pathway has been shown in the bone of diabetic patients with and without Charcot arthropathy. This may serve as future therapeutic target for this severe disease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05314-9.

miR-200a-3p represses osteogenesis of human periodontal ligament stem cells by targeting ZEB2 and activating the NF-κB pathway

OBJECTIVES

Human periodontal ligament stem cells (hPDLSCs) bear multilineage differentiation potential and represent the cytological basis of periodontal tissue regeneration. microRNA (miR) is accepted as a critical regulator of cell differentiation. This study explored the molecular mechanism of miR-200a-3p in osteogenesis of hPDLSCs.

MATERIAL AND METHODS

hPDLSCs were cultured and identified in vitro. miR-200a-3p expression during osteogenic differentiation of hPDLSCs was detected. hPDLSCs were transfected with miR-200a-3p mimic or miR-200a-3p inhibitor. Alkaline phosphatase (ALP) activity, calcified nodules and osteogenesis-related genes of hPDLSCs were measured. The binding relationship between miR-200a-3p and ZEB2 was predicted and verified. hPDLSCs were infected with sh-ZEB2, and then the osteogenic capacity was examined. miR-200a-3p inhibitor-transfected hPDLSCs were infected with sh-ZEB2. The key proteins of the NF-κB pathway were measured.

RESULTS

miR-200a-3p expression was downregulated during osteogenic differentiation of hPDLSCs. Upregulation of miR-200a-3p reduced ALP activity, calcified nodules and osteogenesis-related genes of hPDLSCs, while downregulation of miR-200a-3p facilitated the osteogenesis of hPDLSCs. miR-200a-3p targeted ZEB2. ZEB2 silencing repressed osteogenesis of hPDLSCs. ZEB2 silencing attenuated the promoting effect of miR-200a-3p inhibitor on osteogenesis of hPDLSCs. miR-200a-3p activated the NF-κB pathway by targeting ZEB2.

CONCLUSION

miR-200a-3p repressed osteogenesis of hPDLSCs by targeting ZEB2 and activating the NF-κB pathway. This study may offer insights for periodontal tissue regeneration engineering.

Hsa-miRNA-143-3p regulates the odontogenic differentiation of human stem cells from the apical papilla by targeting NFIC

AIM

To evaluate the effects of hsa-miRNA-143-3p on the cytodifferentiation of human stem cells from the apical papilla (hSCAPs) and the post-transcriptional regulation of Nuclear factor I-C (NFIC).

METHODOLOGY

miRNA expression profiles in human immature permanent teeth and during hSCAP differentiation were examined. hSCAPs were treated with miR-143-3p overexpression or silencing viruses, and the proliferation and odontogenic and osteogenic differentiation of these stem cells, and the involvement of the NFIC pathway, were investigated. Luciferase reporter and NFIC mutant plasmids were used to confirm NFIC mRNA as a direct target of miR-143-3p. NFIC expression analysis in the miR-143-3p overexpressing hSCAPs was used to investigate whether miR-143-3p functioned by targeting NFIC. Student's t-test and chi-square tests were used for statistical analysis.

RESULTS

miR-143-3p expression was screened by microarray profiling and was found to be significantly reduced during hSCAP differentiation (p < .05). Overexpression of miR-143-3p inhibited the mineralization of hSCAPs significantly (p < .05) and downregulated the levels of odontogenic differentiation markers (NFIC [p < .05], DSP [p < .01] and KLF4 [p < .01]), whereas silencing of miR-143-3p had the opposite effect. The luciferase reporter gene detection and bioinformatic approaches identified NFIC mRNA as a potential target of miR-143-3p. NFIC overexpression reversed the inhibitory effect of miR-143-3p on the odontogenic differentiation of hSCAPs.

CONCLUSIONS

miR-143-3p maintained the stemness of hSCAPs and modulated their differentiation negatively by directly targeting NFIC. Thus, inhibition of this miRNA represents a potential strategy to promote the regeneration of damaged tooth roots.

Hydrostatic pressure facilitates calcium deposition and osteogenic gene expression in the osteoblastic differentiation of placenta-derived multipotent cells

OBJECTIVE

We tested the osteoblastic differentiation effects caused by physical stimulation such as hydrostatic pressure using placenta-derived multipotent cells.

MATERIALS AND METHODS

The placenta-derived multipotent cells (PDMCs) were treated with osteogenic medium to induce PDMCs differentiation into osteoblast-like cells. The induced PDMCs were stimulated using hydrostatic pressure at a magnitude of 30 kPa for 1 h/day for up to 12 days. The calcium deposition monitored by Alizarin Red staining and the calcium content of each experimental group were quantified.

RESULTS

The results demonstrated both the calcium deposition and concentration were elevated through hydrostatic pressure stimulation. Moreover, in order to indicate of PDMC osteodifferentiation, RT-qPCR analysis were performed and mRNA expression of osteoblast differentiation markers (type I collagen, alkaline phosphatase, RUNX2, and BGLAP), the bone morphogenetic protein family (BMP1-7) and BMP receptors (BMPR1A, BMPR1B, and BMPR2) were examined. Among them, the mRNA levels of RUNX2, COL1A1, BMP1, BMP3, and BMPR1A increased significantly in the hydrostatic-pressure-stimulated groups, whereas BGLAP, ALP, BMP2, BMP6, BMPR1B, and BMPR2 exhibited a slight upregulation between the control and experimental groups, indicating the specific signal route induced by hydrostatic pressure on PDMCs.

CONCLUSION

Our results revealed the beneficial effects of stem cells stimulated using hydrostatic pressure, which could enhance calcium deposition considerably and facilitate osteodifferentiation, and the results may be applied to tissue regeneration in the near future.

Comparison of Crestal Bone Loss and Osteocalcin Release Kinetics in Immediately and Delayed Loaded Implants: A Randomised Controlled Trial

PURPOSE

To compare concentration and release kinetics of osteocalcin and crestal bone loss under immediate and delayed loading conditions during osseointegration.

MATERIALS AND METHODS

Forty-one patients who were indicated for rehabilitation with dental implants randomly received either implant with placement of permanent prosthesis after 3 months (delayed loading) or implant with placement of permanent prosthesis within 7 days (immediate loading). Radiographic assessment of crestal bone loss at the mesial and distal surface was done at 3, 6 and 12 months after implant placement. Peri-implant sulcular fluid was collected immediately from the buccal surface at two sites after implant insertion and also, at 7, 15, 30 and 90 days after surgery. The level of osteocalcin was evaluated using ELISA and data were compared using two sample t-test. Differences between two groups were analyzed by unpaired Student's t test. Intragroup comparison was done by repeated measures ANOVA.

RESULTS

Mean crestal bone loss was lower in the immediate loading group compared to the delayed loading group at 3, 6 and 12 months (P < 0.001). Intragroup comparison revealed a statistically significant increase in osteocalcin levels in both group I (F = 26712.2) and group II (F = 10497.2) at the predetermined time intervals CONCLUSIONS: Lesser crestal bone loss and early release of osteocalcin was found in the immediately loaded condition than in the delayed loaded condition. The study substantiates that immediately loaded implants shows less crestal bone as well as early release of osteocalcin facilitating upregulation of bone metabolism, improving long term health of bone and prognosis of implants. Immediately loaded implants can be a better treatment protocol provided there is adequate bone and primary stability. This article is protected by copyright. All rights reserved.