Osteopontin in Bone Metabolism and Bone Diseases

The de novo strategy for bifunctional peptides coating to enhance osteointegration capacity of the implant

Bone implants represent a significant global market; however, they are plagued by a high long-term failure rate, with approximately 19.2 % of implants failing within 10 years. This leads to considerable physical pain, mental distress for patients, and a substantial financial burden on public healthcare systems. Herein, we propose a novel strategy that using the interactions between positively charged hexa-arginine (R6) and polyphenols in EGC/Fe MPN to present the bifunctional peptides, cellular adhesive peptide (RGD) and osteogenic growth peptide (OGP), onto implant coatings. To thoroughly investigate the preparation process and the physical and chemical properties of the dual-peptide functionalized coatings, several techniques were employed, including dissipation-quartz crystal microbalance (DQCM), ellipsometry, photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). These methods provided insights into the coating's composition, stability, mechanical properties, and surface roughness. In comparison to single-peptide functionalized coatings, the dual-peptide coatings demonstrated significantly improved performance in cellular adhesion at early stages, long-term cell proliferation, migration, antioxidant activity, osteogenic differentiation, inhibition of osteoclastogenesis, and enhanced in vivo osteointegration. This study contributes to the development of multifunctional coatings tailored to the complex biological processes involved in osteointegration.

An engineered M2 macrophage-derived exosomes-loaded electrospun biomimetic periosteum promotes cell recruitment, immunoregulation, and angiogenesis in bone regeneration

The periosteum, a fibrous tissue membrane covering bone surfaces, is critical to osteogenesis and angiogenesis in bone reconstruction. Artificial periostea have been widely developed for bone defect repair, but most of these are lacking of periosteal bioactivity. Herein, a biomimetic periosteum (termed PEC-Apt-NP-Exo) is prepared based on an electrospun membrane combined with engineered exosomes (Exos). The electrospun membrane is fabricated using poly(ε-caprolactone) (core)-periosteal decellularized extracellular matrix (shell) fibers via coaxial electrospinning, to mimic the fibrous structure, mechanical property, and tissue microenvironment of natural periosteum. The engineered Exos derived from M2 macrophages are functionalized by surface modification of bone marrow mesenchymal stem cell (BMSC)-specific aptamers to further enhance cell recruitment, immunoregulation, and angiogenesis in bone healing. The engineered Exos are covalently bonded to the electrospun membrane, to achieve rich loading and long-term effects of Exos. In vitro experiments demonstrate that the biomimetic periosteum promotes BMSC migration and osteogenic differentiation via Rap1/PI3K/AKT signaling pathway, and enhances vascular endothelial growth factor secretion from BMSCs to facilitate angiogenesis. In vivo studies reveal that the biomimetic periosteum promotes new bone formation in large bone defect repair by inducing M2 macrophage polarization, endogenous BMSC recruitment, osteogenic differentiation, and vascularization. This research provides valuable insights into the development of a multifunctional biomimetic periosteum for bone regeneration.

Ran drives pancreatic cancer metastasis by activating the osteopontin-PI3K/AKT-androgen receptor signaling cascade

The small GTPase Ran has emerged as a key player in cancer metastasis. Our previous studies demonstrated that Ran drives pancreatic cancer metastasis by modulating androgen receptor (AR) expression. However, the detailed mechanisms by which Ran regulates AR expression remain unclear. This study aimed to elucidate the regulatory mechanisms through which Ran influences AR expression in the context of pancreatic cancer metastasis. We observed elevated levels of Ran, osteopontin (OPN), and AR in metastatic lymph node tissues, with OPN positively correlated with either Ran or AR expression. Ran silencing led to decreased levels of OPN and AR, whereas Ran upregulation increased their expression. Notably, OPN overexpression restored AR levels in Ran-silenced cells, whereas OPN knockdown diminished the inductive effect of Ran on AR expression. Additionally, OPN knockdown decreased AR expression and was associated with reduced activation of the PI3K/AKT signaling pathway. Functional assays revealed that silencing OPN significantly impaired the mobility and invasion of pancreatic cancer cells and restricted hepatic metastasis. Conversely, OPN overexpression restored the impaired metastasis caused by Ran knockdown. Furthermore, inhibiting PI3K/AKT signaling abolished the promoting effects of either Ran or OPN on pancreatic cancer metastasis. Importantly, re-expressing AR reversed the inhibitory effects of Ran or OPN silencing on the mobility and invasion of pancreatic cancer cells. In summary, Ran induces AR expression through the regulation of the OPN-PI3K/AKT signaling cascade. The Ran-OPN-PI3K/AKT-AR signaling pathway is crucial for driving pancreatic cancer metastasis.

Multifunctional micro/nano-textured titanium with bactericidal, osteogenic, angiogenic and anti-inflammatory properties: Insights from in vitro and in vivo studies

Titanium (Ti) is widely used as an implantable material for bone repair in orthopedics and dentistry. However, Ti implants are vulnerable to bacterial infections, which can compromise patient recovery and lead to implant failure. While a controlled inflammatory response promotes bone regeneration, chronic inflammation caused by infections can lead to implant failure. Bone repair is a complex process in which inflammation, angiogenesis and osteogenesis are tightly interconnected, requiring cooperation between mesenchymal stem cells (MSC), macrophages and endothelial cells. Here, we fabricated bio-inspired Ti implants with either microstructured (Micro Ti) or nanostructured (Nano Ti) surface textures that exhibit robust mechano-bactericidal properties. In vitro, both textured surfaces improved blood coagulation and osteogenic marker expression compared to smooth Ti surfaces. Additionally, Nano Ti promoted macrophage polarization towards the M2 phenotype and enhanced the paracrine effects of MSCs on angiogenesis, key processes in tissue regeneration. In vivo kinetic analysis of bone reconstruction in a rat calvarial model showed that Nano Ti improved osseointegration, as evidenced by increased bone volume, mineral density, and bone-implant contact. Notably, the Micro Ti surface showed no significant differences from the control implants. These findings highlight the potential of mechano-bactericidal surface nanopatterns to simultaneously prevent infections and enhance osseointegration by modulating protein adsorption, inflammation, angiogenesis and osteogenesis. This study provides new insights into the development of bifunctional Ti implants, offering new perspectives for the next generation of implantable bone-related biomaterials.

Dysregulation of miR-106a-5p/PTEN axis associated with progression and diagnostic of postmenopausal osteoporosis

OBJECTIVE

Postmenopausal osteoporosis (PMOP) is a bone disorder in postmenopausal women and a significant risk factor for fragility fractures. This study aims to explore the role of miR-106a-5p in the pathogenesis of PMOP and its potential as a diagnostic biomarker.

METHODS

220 postmenopausal women were recruited. The levels of miR-106a-5p, PTEN, and osteogenic-related genes were quantified using qRT-PCR. The relative protein of PTEN was detected using Western blotting. ROC curve and Pearson correlation were employed to evaluate the diagnostic value and relationships between variables. To model iron accumulation, hFOB1.19 osteoblasts were treated with ferric ammonium citrate (FAC). Cell proliferation and apoptosis were assessed using the CCK-8 and flow cytometry. The target relationship was verified using dual-luciferase assays.

RESULTS

miR-106a-5p levels were reduced, while PTEN levels were increased in PMOP. miR-106a-5p was positively correlated with bone mineral density and negatively correlated with ferritin. In the FAC-treated cells, miR-106a-5p decreased, and PTEN increased. Dual-luciferase assays confirmed that miR-106a-5p targets PTEN. Successful transfection was confirmed by observing the corresponding changes in miR-106a-5p and PTEN expression. Up-regulated miR-106a-5p increased the PTEN protein level, mRNA expression of RUNX2, OPN, and OCN, promoted cell proliferation, and decreased cell apoptosis under iron accumulation conditions. These effects were reversed by the upregulation of PTEN.

CONCLUSION

miR-106a-5p has the potential to diagnose osteoporosis in postmenopausal women and is linked to ferritin levels. miR-106a-5p plays a protective role in PMOP by regulating PTEN under conditions of iron accumulation, suggesting its potential as a promising biomarker for PMOP.

New Qiangguyin activates Wnt/β-catenin pathway by down-regulating Notum to improve osteoporosis in rats

BACKGROUND

Qiangguyin (QGY) is a traditional Chinese medicine prescription for postmenopausal osteoporosis. We modified the formula based on QGY and named it new QGY (N-QGY), and studied the therapeutic mechanism of N-QGY on osteoporosis.

METHOD

Osteoporosis rat model was established by bilateral ovariectomy, and the rats were treated with exosomes from osteoclasts treated with N-QGY. Then the bone morphological parameters were detected by micro-computed tomography, the levels of Procollagen I N-terminal Propeptide (PINP), β-crosslaps (β-CTX), Estrogen and osteocalcin (OCN) were detected by ELISA, and the expressions of Alkaline phosphatase (ALP), Runt-related transcription factor 2 (RUNX2), Osteopontin (OPN), Notum and β-catenin were detected by Western blot. Subsequently, the primary cultured bone marrow mesenchymal stem cells (BMSCs) were transfected with Notum overexpression plasmid and co-cultured with exosomes from osteoclasts treated with N-QGY or interleukin (IL)-1β. Subsequently, the cell viability and the expression of bone formation-related genes or proteins were detected. ALP staining and alizarin red staining were performed.

RESULT

In vivo, N-QGY improved the bone morphological indexes and serum levels of PINP, β-CTX, estrogen, ALP, RUNX2 and OPN in bone tissues or serum, down-regulated Notum expressions and activated β-catenin pathway in bone tissues. The exosomes derived from N-QGY-treated osteoclast alleviated the destructive effect of exosomes derived from osteoclast on osteogenic differentiation of BMSCs, which was embodied in promoting the activity of BMSCs, up-regulating the levels of ALP, RUNX2, OPN and OCN, promoting bone mineralization and activating β-catenin pathway.

CONCLUSION

N-QGY activates Wnt/β-catenin pathway by down-regulating Notum to improve osteoporosis in rats.

Bone-derived factors mediate crosstalk between skeletal and extra-skeletal organs

Bone has long been acknowledged as a fundamental structural entity that provides support and protection to the body's organs. However, emerging research indicates that bone plays a crucial role in the regulation of systemic metabolism. This is achieved through the secretion of a variety of hormones, cytokines, metal ions, extracellular vesicles, and other proteins/peptides, collectively referred to as bone-derived factors (BDFs). BDFs act as a medium through which bones can exert targeted regulatory functions upon various organs, thereby underscoring the profound and concrete implications of bone in human physiology. Nevertheless, there remains a pressing need for further investigations to elucidate the underlying mechanisms that inform the effects of bone on other body systems. This review aims to summarize the current findings related to the roles of these significant modulators across different organs and metabolic contexts by regulating critical genes and signaling pathways in vivo. It also addresses their involvement in the pathogenesis of various diseases affecting the musculoskeletal system, circulatory system, glucose and lipid metabolism, central nervous system, urinary system, and reproductive system. The insights gained from this review may contribute to the development of innovative therapeutic strategies through a focused approach to bone secretomes. Continued research into BDFs is expected to enhance our understanding of bone as a multifunctional organ with diverse regulatory roles in human health.

Polydopamine-assisted dual metal ion modification of titanium: Enhancing osseointegration and antibacterial performance

Titanium (Ti) implants are widely used for tooth replacement due to their exceptional mechanical properties and high biocompatibility. However, their inherently inert surface limits osteogenic potential and makes them prone to bacterial colonization, increasing the risk of biofilm formation and implant-related infections. To address these limitations, surface modification of Ti is essential. This study aimed to enhance the surface properties of Ti by coating it with polydopamine (PDA) and further doping it with copper and calcium ions. TPDA was prepared and subsequently used to fabricate TPDA@Cu and TPDA@CuCa samples. Material characterization confirmed that TPDA@CuCa exhibited excellent surface wettability and biocompatibility, with Cu2 + and Ca2+ being continuously and stably released in liquid environments. Additionally, TPDA@CuCa significantly improved protein adsorption, facilitating favorable cellular interactions. In vitro experiments demonstrated that TPDA@CuCa exhibited strong antimicrobial activity against Escherichia coli and Staphylococcus aureus, enhanced osteoblast adhesion, mineralization, and upregulated osteogenic gene expression. This bifunctional surface modification strategy offers a promising approach to enhancing both the osteogenic and antibacterial properties of Ti implants.

Injectable Piezoelectric Hydrogel Promotes Tendon-Bone Healing via Reshaping the Electrophysiological Microenvironment and M2 Macrophage Polarization

Rotator cuff tear (RCT) is a common musculoskeletal disease that poses challenges for functional regeneration of the tendon-bone interface (TBI). The transition of TBI between soft and hard tissues determines its structural and physiological environment complexity. Here, we present an injectable biopiezoelectric material PVA/CNF/BTO@PDA (Piezoelectric) hydrogel based on three-dimensional (3D) printing inspired by the "muscle-electrical coupling". This Piezoelectric hydrogel indicated desirable piezoelectric and mechanical properties, excellent biodegradability, and biosafety. In vitro, electrical stimulation from Piezoelectric hydrogel by the Flexcell Tissue Train system promoted the polarization of macrophages to the M2 phenotype, directing the targeted aggregation and zonal-specific differentiation of bone mesenchymal stem cells (BMSCs) for TBI formation. Also, optimal piezoelectric stimulation of the Piezoelectric hydrogel could alleviate inflammatory factor expression and regulate the osteotendinogenic differentiation of BMSCs under an H2O2/IL-1β inflammation environment. Furthermore, in vivo application of injectable Piezoelectric hydrogel demonstrates its regenerative potential, indicating that physiological repair with Piezoelectric hydrogel significantly accelerates and promotes TBI healing in a chronic RCT model. Therefore, our findings propose a new therapeutic strategy for functional TBI regeneration and enhance the treatment outcomes for RCT.

Curcumin Ameliorated Glucocorticoid-Induced Osteoporosis While Modulating the Gut Microbiota and Serum Metabolome

Glucocorticoid-induced osteoporosis (GIOP) is the leading cause of secondary osteoporosis. Recently, the "bone-gut axis" theory has linked bone development with gut microbial diversity, community composition, and metabolites. Curcumin, a well-studied polyphenol, shows potential in mitigating bone loss and osteoporosis. Alendronate, a standard therapeutic agent for osteoporosis, serves as a positive control in this investigation. The study demonstrates the potency of curcumin in reducing bone loss and restoring bone mineral density, enhancing trabecular parameters notably through increased trabecular number, volume, and thickness and reduced bone marrow cavity size. Gut microbiome sequencing revealed that both curcumin and alendronate treatments similarly enhanced gut microbial diversity and altered microbiota composition, increasing beneficial bacteria (Akkermansia_muciniphila, Dubosiella_sp910585105, and Ruminococcus_sp910584195) while reducing harmful bacteria (Treponema_D_sp910584475 and Duncaniella_sp910584825). Furthermore, significant changes in serum levels of metabolites including raffinose, ursolic acid, spermidine, inosine, hypoxanthine, thiamine, and pantothenic acid were observed post-treatment with curcumin or alendronate. Importantly, these beneficial metabolites and microorganisms were negatively correlated with inflammatory cytokines. In conclusion, curcumin holds promise for use against GIOP by modulating the gut microbiome and serum metabolome as well as reducing systemic inflammation.

Molecular Mechanisms and Therapeutic Role of Intra-Articular Hyaluronic Acid in Osteoarthritis: A Precision Medicine Perspective

Background: Osteoarthritis (OA) is a degenerative joint disease characterized by progressive cartilage breakdown, synovial inflammation, and pain, which leads to significant disability. IAHA is widely used because of its viscoelastic properties, which restore synovial fluid homeostasis and reduce symptoms. However, emerging evidence suggests that IAHA exerts additional biological effects including chondroprotection, inflammatory modulation, oxidative stress reduction, and pain modulation, which may influence disease progression. Objective: This narrative review examines the biological mechanisms underlying IAHA's role in OA management. The review explored IAHA's effects on synovial fluid viscoelasticity, inflammatory cytokine modulation, cartilage preservation, oxidative stress regulation, and pain pathways, emphasizing the influence of molecular weight variations on therapeutic efficacy. Additionally, this review evaluates IAHA's integration into multimodal treatment strategies, its potential disease-modifying effects, and future directions for personalized treatment approaches. Methods: A comprehensive literature review was conducted using PubMed, Cochrane Library, EMBASE, Scopus, and Web of Science for studies published between January 2000 and March 2024. The search focused on IAHA's molecular, cellular, and biochemical effects in OA and clinical findings assessing its impact on joint function, pain relief, and disease progression. Results: IAHA improves synovial fluid lubrication, reduces proinflammatory cytokines (IL-1β, TNF-α), inhibits matrix metalloproteinases (MMPs), scavenges reactive oxygen species (ROS), and modulates nociceptive pathways. High-molecular-weight IAHA demonstrates superior efficacy in advanced OA, while low-molecular-weight formulations may be better suited for early-stage disease. Although IAHA's symptom relief is comparable to corticosteroids and NSAIDs, its favorable safety profile and emerging disease-modifying potential support its long-term use in OA management. Conclusions: IAHA represents a multifaceted therapeutic approach bridging symptomatic relief and regenerative strategies. While long-term efficacy, optimal administration protocols, and patient-specific responses remain subjects of ongoing research, refining treatment selection criteria, dosing regimens, and combination strategies may enhance clinical outcomes. Future studies should explore biomarker-driven approaches, standardize treatment protocols, and assess IAHA's synergy with regenerative medicine to optimize its role in OA management.

Emerging Roles of Eosinophils in Bone

PURPOSE OF THE REVIEW

Eosinophils are traditionally known for their role in immune defense against parasites and their involvement in various immunopathologies, including eosinophilic airway diseases, eosinophilic dermatoses, and gastrointestinal disorders. However, recent findings from our group and other leading laboratories have broadened this perspective, revealing that eosinophils also play crucial roles in tissue development, homeostasis, and regeneration. This review aims to highlight the regulatory functions of eosinophils within the bone niche and emphasize the importance of further research into their role in bone biology.

RECENT FINDINGS

Growing evidence suggests that eosinophils are key regulators of bone metabolism, extending beyond their established roles in immunity and inflammation. They contribute to bone homeostasis by inhibiting osteoclast differentiation, helping to prevent excessive bone resorption in osteoporosis and inflammatory arthritis. Additionally, eosinophils may promote osteoblast-mediated bone formation, modulate the mesenchymal and hematopoietic stem cell niche, and contribute to the bone microenvironment by affecting vascularization and extracellular matrix composition. However, their impact may vary under pathological conditions. Patients with eosinophilic disorders are often at an increased risk of osteoporosis and fragility fractures, though this is largely attributed to disease-related treatments rather than eosinophil activity itself. Despite emerging insights into the role of eosinophils in bone biology, the underlying mechanisms remain incompletely understood. Further research is essential to elucidate how eosinophils influence bone physiology and pathology.

Modulating the PD-1-FABP5 axis in ILC2s to regulate adipose tissue metabolism in obesity

Obesity is closely linked to metabolic dysregulation and chronic inflammation, which significantly impact immune cell functions in adipose tissue. Type 2 innate lymphoid cells (ILC2s) have emerged as key regulators of energy homeostasis, positioning them as promising targets for obesity management. However, the mechanisms governing ILC2 activity and their therapeutic potential in obesity are not fully understood. In this study, we demonstrate that ILC2s in obese adipose tissue exhibit increased PD-1 expression, leading to an exhausted phenotype with diminished cytokine production and proliferation. Elevated osteopontin (OPN) levels in adipose tissue are associated with higher PD-1 expression on ILC2s, while adipocyte-derived PD-L1 interacts with PD-1 to further impair ILC2 functionality. Importantly, blocking PD-1 signaling prevents weight gain and alleviates obesity-related metabolic dysfunctions. In addition, the adoptive transfer of PD-1-deficient ILC2s reduces diabetic phenotypes in obese models. Mechanistically, PD-1 signaling drives metabolic reprogramming in ILC2s, affecting fatty acid uptake and energy metabolism through the downregulation of fatty acid binding protein 5 (FABP5). These results, corroborated by findings in human adipose tissue, suggest a conserved OPN-PD-1 axis. Our study identifies the OPN-PD-1-FABP5 pathway as a crucial regulator of ILC2 function in adipose tissue and presents an emerging immune cell-based therapeutic target for obesity treatment.

Facile Nanocomposite Hydrogel Scaffold with Sustained Drug Release and Osteo-Immunomodulatory Effects to Enhance Bone Regeneration

High-quality repair of critical bone defects without exogenous cells remains a major clinical challenge worldwide. Herein, we fabricated a nanocomposite hydrogel scaffold (ASA/MSNs/CSH) by incorporating aspirin (ASA)-loaded mesoporous silica nanoparticles (MSNs) into genipin-cross-linked chitosan hydrochloride (CSH). The resulting scaffold was designed to provide immunomodulatory support during the process of bone regeneration. ASA-loaded MSNs were encapsulated in CSH, forming a composite hydrogel capable of sustained drug release for over 35 days. This composite hydrogel was able to meet key criteria for physicochemical properties, mechanical strength, biocompatibility, and cell affinity. The study showed that the scaffolds could create a beneficial immune microenvironment through reducing inflammation and inducing macrophages toward M2-polarized phenotype in vitro. The scaffold also enhanced the osteogenesis of bone marrow mesenchymal stromal cells, as demonstrated by enhancing the alkaline phosphatase activity and the formation of calcium nodules. Meanwhile, the TGF-β/Smad pathway was identified as an important regulatory mechanism via Western blot analysis. Moreover, the critical size defect models were established in rat skulls, and the results demonstrated that the ASA/MSNs/CSH nanocomposite scaffolds exhibited adequate biocompatibility, superior anti-inflammatory effect, and an admirable capacity for bone regeneration in vivo.

Osteogenic Effects of Bioactive Compounds Found in Fruits on Mesenchymal Stem Cells: A Review

Phytochemicals, which are bioactive compounds contained in fruits, vegetables, and teas, have a positive effect on human health by having anti-inflammatory, antioxidant, and anticarcinogenic effects. Several studies have highlighted the ability of bioactive compounds to activate key cellular enzymes associated with important signaling pathways related to cell division and proliferation, as well as their role in inflammatory and immunological responses. Some phytochemicals are associated with increased proliferation, differentiation, and expression of markers related to osteogenesis, bone formation, and mineralization by activating various signaling pathways. The objective of this study was to clarify which bioactive compounds present in fruits have osteogenic effects on mesenchymal stem cells and the possible associated mechanisms. A literature search was conducted in the LILACS, MEDLINE, and PubMed databases for pertinent articles published between 2014 and 2024. This review included 34 articles that report the osteogenic effects of various bioactive compounds found in different fruits. All the articles reported that phytochemicals play a role in enhancing the regenerative properties of mesenchymal cells, such as proliferation, osteogenic differentiation, secretion of angiogenic factors, and extracellular matrix formation. This review highlights the potential of these phytochemicals in the prevention and treatment of bone diseases. However, more studies are recommended to identify and quantify the therapeutic dose of phytochemicals, investigate their mechanisms in humans, and ensure their safety and effectiveness for health, particularly for bone health.

Clinical significance of microRNA-328-3p and bone metabolism biomarkers in gout patients with different musculoskeletal ultrasonography imaging

AIMS

MicroRNA (miRNA) participates in the pathophysiological processes of multiple metabolic diseases, including gout. In gout patients, there is concomitant derangement of bone metabolism. The study aimed to explore the correlation of different ultrasonic manifestations and miR-328-3p levels with bone metabolic markers in gout patients.

METHODS

A total of 320 gout patients were grouped according to musculoskeletal ultrasound (MSUS) imaging. Serum osteocalcin (BGP), C-terminal telopeptide of type I collagen (CTX-I) and osteopotin (OPN) levels were detected to evaluate bone metabolism. Serum miR-328-3p levels were detected via qRT-PCR. Pearson's correlation analysis was performed to explore the relationships between the variables.

RESULTS

Patients with tophi accompanied by bone erosion demonstrated significantly elevated levels of BGP and OPN compared to those with tophi or aggregate of MSU crystals in the absence of bone erosions. Cases with long course of disease exhibited more severe bone destruction. Cases without specific clinical manifestations presented the highest levels of serum miR-328-3p, whereas those with bone erosions demonstrated the lowest values. Significantly negative correlations were also detected for serum miR-328-3p levels with BGP and OPN values in all gout patients.

CONCLUSION

Serum miR-328-3p levels were associated with diverse MSUS manifestations in gout patients. MSUS imaging and miR-328-3p levels are capable of reflecting the joint impairment in gout patients.

Fibroblast growth factor 23 neutralizing antibody partially rescues bone loss and increases hematocrit in sickle cell disease mice

Fibroblast Growth Factor 23 (FGF23) is increased in serum of humanized Sickle Cell Disease (SCD) mice. Since FGF23 is associated with impaired bone formation, we examined the effect of FGF23-neutralizing antibody (FGF23Ab) on bone loss in SCD mice. Healthy control (Ctrl) and SCD 5-months-old female mice were treated with FGF23Ab or isotype-specific IgG for 6 weeks. Significantly reduced hematocrit in SCD mice was increased by FGF23Ab. MicroCT of SCD femurs revealed no significant reduction in metaphyseal bone volume/total volume vs. Ctrl mice. However, histomorphometry of SCD femur revealed significantly reduced mineral apposition rate, bone formation rate, inter-label thickness, and osteoid surface, which were increased by FGF23Ab. Significantly increased osteoclast number/bone perimeter in SCD mice was reduced by FGF23Ab. Bone marrow stromal cells (BMSC) cultured in osteogenic media revealed significantly reduced mineralized nodules in SCD-IgG-BMSC that was increased in SCD-FGF23Ab-BMSC. FGF23 and αKlotho protein was significantly increased in SCD-IgG-BMSC and was not reduced by FGF23Ab. However, phosphorylated FGF Receptor-1, the receptor through which FGF23 signals, was significantly reduced by FGF23Ab. The mineralization inhibitor osteopontin was significantly increased in SCD-IgG-BMSC cultures and was reduced by FGF23Ab. We conclude that FGF23Ab may be efficacious in improving some parameters of reduced bone formation in female SCD mice.

Osteopontin attenuates the foreign-body response to silicone implants

The inflammatory process resulting in the fibrotic encapsulation of implants has been well studied. However, how acellular dermal matrix (ADM) used in breast reconstruction elicits an attenuated foreign-body response (FBR) remains unclear. Here, by leveraging single-cell RNA-sequencing and proteomic data from pairs of fibrotically encapsulated specimens (bare silicone and silicone wrapped with ADM) collected from individuals undergoing breast reconstruction, we show that high levels of the extracellular-matrix protein osteopontin are associated with the use of ADM as a silicone wrapping. In mice with osteopontin knocked out, FBR attenuation by ADM-coated implants was abrogated. In wild-type mice, the sustained release of recombinant osteopontin from a hydrogel placed adjacent to a silicone implant attenuated the FBR in the absence of ADM. Our findings suggest strategies for the further minimization of the FBR.

Osteopontin promotes keratinocyte proliferation by G0/G1 cell cycle arrest in psoriasis

Psoriasis is a chronic inflammatory dermatological disorder that is featured by the abnormal activation of epidermal keratinocytes. Osteopontin (OPN) is a multifunctional phosphoprotein upregulated in psoriasis. OPN levels in the skin of psoriasis patients and healthy subjects were assessed by immunohistochemistry. To evaluate the potential role of OPN in keratinocyte proliferation, the knockdown model of OPN was constructed using OPN siRNA. The proliferative activity of HaCaT cells was assessed via the CCK-8 and EdU cell proliferation assays. The cell cycle and apoptosis were analyzed using flow cytometry. Western blot assay was conducted in order to investigate the expression levels of cyclins, CDKs, and apoptosis-associated proteins. OPN expression was increased in the epidermis of psoriasis lesions and OPN knockdown inhibited the proliferation of keratinocytes. OPN affected keratinocyte proliferation by G0/G1 cell cycle arrest and promoted their apoptosis, which involved the regulation of cyclins (Cyclin D1 and Cyclin A2), cyclin-dependent kinases (CDK2 and CDK4), and apoptosis proteins (Bim, Bcl-2, and Caspase-3) in keratinocytes. OPN expression was significantly higher in keratinocytes of psoriasis lesions. OPN knockdown inhibited the keratinocyte proliferation, arrested the G0/G1 cell cycle, and promoted apoptosis. This suggests that OPN may provide a new mechanism for the proliferation of keratinocytes in psoriasis.

Ano5Cys360Tyr mutation leads to bone dysfunction of gnathodiaphyseal dysplasia via disturbing Akt signaling

Background

Gnathodiaphyseal dysplasia (GDD) is a rare autosomal dominant genetic disease characterized by osteosclerosis of the tubular bones and cemento-osseous lesions of the mandibles. Anoctamin 5 (ANO5) is the pathogenic gene, however, the specific molecular mechanism of GDD remains unclear. Herein, a knockin (Ano5 KI/KI ) mouse model expressing the human mutation p.Cys360Tyr was used to investigate the role of Akt signaling in enhanced osteogenesis and decreased osteoclastogenesis in GDD.

Methods

Bone marrow-derived macrophages (BMMs) and mouse calvarial osteoblasts (mCOBs) were isolated from homozygous Ano5 KI/KI mice and treated with SC79, a specific Akt activator. The differentiation and F-actin ring formation of osteoclasts were examined by TRAP and phalloidin staining, respectively. Osteoblast differentiation and mineralization were examined by ALP and alizarin red staining. The expression of bone remodeling-related factors was measured by qRT-PCR.

Results

Akt activation promoted the generation of TRAP-positive multinucleated osteoclasts and the formation of actin rings in Ano5 KI/KI BMMs cultures, accompanied by increased expression of Nfatc1, Trap, Dc-stamp, Mmp9, Ctsk, and Atp6v0d2. Additionally, Ano5 Cys360Tyr mutation down-regulated the Akt phosphorylation level in osteoblast. ALP activity and matrix mineralization capacity in Ano5 KI/KI osteoblast cultures were inhibited after SC79 stimulation, with reduced expression of Runx2, Opn, Col1a1, and Ocn.

Conclusion

Akt activation by SC79 stimulation can obviously rescue abnormal increased osteogenesis and decreased osteoclastogenesis in Ano5 KI/KI mouse model, which demonstrated that disturbed Akt signaling pathway may play a pivotal role in the pathogenesis of GDD, and an Akt activator is probable a therapeutic target for GDD.

Stigmasterol, a Major Component of Cornus Officinalis, Ameliorates Osteoporosis in Diabetes Mellitus Effects by Increasing Bone Mineral Density

OBJECTIVES

This study investigated the therapeutic effects of stigmasterol (STG), derived from Cornus officinalis, on osteoporosis in rats with type 2 diabetes mellitus (T2DM).

METHODS

Twenty-four Male Sprague-Dawley rats (6 weeks old) were used to establish a T2DM model and were divided into four groups: normal diet (ND), high-fat diet (HFD), low-dose STG (STG-L, 100 mg/kg), and high-dose STG (STG-H, 200 mg/kg). The rats received daily gavage treatments for four weeks. Therapeutic effects were assessed by examining femoral bone structure, serum bone formation markers (P1NP, osteocalcin, and osteoprotegerin), bone resorption indices (CTX-1 and RANKL), and osteogenic protein expression (Runx2, osteopontin, and COL1A1).

RESULTS

STG significantly reduced fasting blood glucose levels and improved insulin resistance in T2DM rats. It enhanced trabecular bone microstructure, with the STG-H group demonstrating superior effects. Compared to the HFD group, STG increased bone mineral density, bone volume fraction (BV/TV), and trabecular thickness, while reducing bone surface-to-volume ratio (BS/BV) and trabecular separation. STG also elevated serum levels of P1NP, osteocalcin, and osteoprotegerin, while reducing CTX-1 and RANKL. Western blot analysis revealed increased expression of Runx2, osteopontin, and COL1A1 in femoral tissues.

CONCLUSIONS

STG appears to alleviate osteoporosis in diabetes by improving bone microstructure, promoting bone formation, and reducing bone resorption, indicating its potential as a therapeutic option for managing osteoporosis.

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.

Bioactive Carbon Dots from Clove Residue: Synthesis, Characterization, and Osteogenic Properties

Background/Objectives: Bone regeneration using nanomaterial-based approaches shows promise for treating critical bone defects. However, developing sustainable and cost-effective therapeutic materials remains challenging. This study investigates the osteogenic potential of clove-derived carbon dots (C-CDs) for bone regeneration applications. Methods: C-CDs were synthesized using a green hydrothermal method. The osteogenic potential was evaluated in human bone marrow-derived mesenchymal stem cells (hBM-MSCs) and validated using ectopic bone formation and calvarial defect models. Results: C-CDs demonstrated uniform morphology (~10 nm) with efficient cellular uptake. In vitro studies showed successful osteogenic differentiation through the upregulation of RUNX2, ALP, COL1A1, and BMP-2 mediated by Wnt/β-catenin/GSK3β and BMP signaling pathways. In vivo models have also demonstrated that C-CDs are effective in promoting bone regeneration. Conclusions: These findings establish C-CDs as promising candidates for bone regeneration therapy, offering a sustainable alternative to current treatments. While optimization is needed, their demonstrated osteogenic properties warrant further development for regenerative medicine applications.

Histomorphometric and immunohistochemical assessment of treated dentin matrix delivered by platelet-rich fibrin for socket preservation in rabbit model

OBJECTIVES

This study aimed to test treated dentine matrix (TDM) with platelet-rich fibrin (PRF) for socket preservation, following tooth extraction compared to synthetic grafting material Nanobone (NB) with PRF.

MATERIALS AND METHODS

Study was conducted on New Zealand rabbits (n = 40). Bilateral first lower premolar extraction was performed, with one side left empty and the other side filled with (PRF) in one group (n = 20). In the other group (n = 20), one side was filled with TDM/PRF while the other side was filled with NB/ PRF. After one and three months, rabbits were euthanized, and the socket area was examined using haematoxylin and eosin (H&E) and Goldner Masson trichrome stains. One-way ANOVA and post-hoc tests were used for histomorphometric analysis. Immunohistochemical analysis of osteopontin was carried out.

RESULTS

Histological analysis of NB/PRF and TDM/PRF groups showed a higher level of new bone formation in comparison to the control and PRF groups. Histomorphometric analysis revealed a significant increase in new bone formation in the TDM/PRF group compared to the NB/PRF group after one and three months (p = 0.042 and p < 0.001), respectively. There were no significant differences in the percentages of unmineralized bone between the TDM/PRF and NB/PRF groups at both intervals (p = 0.375 and 0.352, respectively). Regarding immunohistochemistry, NB/PRF showed the highest osteopontin immune expression followed by TDM/PRF. No significant differences were detected between both groups at both intervals (p = 0.234 & 0.607 respectively).

CONCLUSIONS

TDM/PRF showed the ability to form new bone in extraction sockets in rabbits.

CLINICAL RELEVANCE

TDM/PRF can be used as an alveolar bone grafting material for socket preservation.

Non-Canonical Wnt16 and microRNA-145 Mediate the Response of Human Bone Marrow Stromal Cells to Additively Manufactured Porous 3-Dimensional Biomimetic Titanium-Aluminum-Vanadium Constructs

Metal 3D printing is increasingly being used to manufacture titanium-aluminum-vanadium (Ti6Al4V) implants. In vitro studies using 2D substrates demonstrate that the osteoblastic differentiation of bone marrow stromal cells (MSCs) on Ti6Al4V surfaces, with a microscale/nanoscale surface topography that mimics an osteoclast resorption pit, involves non-canonical Wnt signaling; Wnt3a is downregulated and Wnt5a is upregulated, leading to the local production of BMP2 and semaphorin 3A (sema3A). In this study, it was examined whether the regulation of MSCs in a 3D environment occurs by a similar mechanism. Human MSCs from two different donors were cultured for 7, 14, or 21 days on porous (3D) or solid (2D) constructs fabricated by powder-bed laser fusion. mRNA and secretion of osteoblast markers, as well as factors that enhance peri-implant osteogenesis, were analyzed, with a primary focus on the Wnt family, sema3A, and microRNA-145 (miR-145) signaling pathways. MSCs exhibited greater production of osteocalcin, latent and active TGFβ1, sema3A, and Wnt16 on the 3D constructs compared to 2D, both of which had similar microscale/nanoscale surface modifications. Wnt3a was reduced on 2D constructs as a function of time; Wnt11 and Wnt5a remained elevated in the 3D and 2D cultures. To better understand the role of Wnt16, cultures were treated with rhWnt16; endogenous Wnt16 was blocked using an antibody. Wnt16 promoted proliferation and inhibited osteoblast differentiation, potentially by reducing production of BMP2 and BMP4. Wnt16 expression was reduced by exogenous Wnt16 in 3D cells. Addition of the anti-Wnt16 antibody to the cultures reversed the effects of exogenous Wnt16, indicating an autocrine mechanism. Wnt16 increased miR-145-5p, suggesting a potential feedback mechanism. The miR-145-5p mimic increased Wnt16 production and inhibited sema3A in a 3D porous substrate-specific manner. Wnt16 did not affect sema3A production, but it was reduced by miR-145-5p mimic on the 3D constructs and stimulated by miR-145-5p inhibitor. Media from 7-, 14-, and 21-day cultures of MSCs grown on 3D constructs inhibited osteoclast activity to a greater extent than media from the 2D cultures. The findings present a significant step towards understanding the complex molecular interplay that occurs in 3D Ti6Al4V constructs fabricated by additive manufacturing. In addition to enhancing osteogenesis, the 3D porous biomimetic structure inhibits osteoclast activities, indicating its role in modulating bone remodeling processes. Our data suggest that the pathway mediated by sema3A/Wnt16/miR145-5p was enhanced by the 3D surface and contributes to bone regeneration in the 3D implants. This comprehensive exploration contributes valuable insights to guide future strategies in implant design, customization, and ultimately aims at improving clinical outcomes and successful osseointegration.

Deferoxamine functionalized alginate-based collagen composite material enhances the integration of metal implant and bone interface

Poor osseointegration markedly compromises the longevity of prostheses. To enhance the stability of titanium implants, surface functionalization is a proven strategy to promote prosthesis-bone integration. This study developed a hydrogel coating capable of simultaneous osteoangiogenesis and vascularization by incorporating deferoxamine (DFO) into a sodium alginate mineralized collagen composite hydrogel. The physicochemical properties of this hydrogel were thoroughly analyzed. In vivo and in vitro experiments confirmed the hydrogel scaffold's osteogenic and angiogenic capabilities. Results indicated that sodium alginate notably enhanced the mechanical characteristics of the mineralized collagen, allowing it to fully infiltrate the interstices of the 3D-printed titanium scaffold. Furthermore, as the hydrogel degraded, collagen, calcium ion, phosphate ion, and DFO were gradually released around the scaffolds, altering the local osteogenic microenvironment and strongly inducing new bone tissue growth. These findings offer novel perspectives for the creation and utilization of functionalized bone implant materials.

Exosomal miR-122 derived from M2 macrophages induces osteogenic differentiation of bone marrow mesenchymal stem cells in the treatment of alcoholic osteonecrosis of the femoral head

Alcoholic osteonecrosis of the femoral head (AIONFH) is caused by long-term heavy drinking, which leads to abnormal alcohol and lipid metabolism, resulting in femoral head tissue damage, and then pathological necrosis of femoral head tissue. If not treated in time in clinical practice, it will seriously affect the quality of life of patients and even require hip replacement to treat alcoholic femoral head necrosis. This study will confirm whether M2 macrophage exosome (M2-Exo) miR-122 mediates alcohol-induced BMSCs osteogenic differentiation, ultimately leading to the inhibition of femoral head necrosis. M2 macrophages were identified by flow cytometry, and the isolated exosomes were characterized by transmission electron microscopy (TEM) and Nanoparticle Tracking Analysis (NTA). Next, miR-122 was overexpressed by transfecting miR-122 mimic, and the expression of miR-122 in M2 macrophages and their exosomes was evaluated. Subsequently, the effect of exosomal miR-122 on the osteogenic differentiation ability of BMSCs was detected, including cell proliferation, expression of osteogenic-related genes (RUNX2, BMP2, OPN, ALP), and calcium nodule formation. Finally, the therapeutic effect of M2-Exo was analyzed in a rat model of AIONFH, and bone repair and pathological damage were evaluated by Micro-CT, RT-qPCR, HE, Masson staining, and immunohistochemistry (COL I). The results showed that M2 macrophages were successfully polarized, with an average M2-Exo particle size of 156.4 nm and a concentration of 3.2E + 12 particles/mL. The expression of miR-122 in M2 macrophages is significantly higher than that in M0 macrophages, and miR-122 mimic can increase the content of miR-122 in M2-Exo. miR-122 in M2-Exo can promote osteogenic differentiation of rat bone marrow BMSCs, enhance cell viability, and increase the expression of osteogenesis-related genes. After being applied to the AIONFH rat model, the injection of M2-exo and miR-122 mimics significantly improved the repair effect of articular cartilage, alleviated pathological changes, and promoted the regeneration of bone tissue. M2-macrophage-derived exosomal miR-122 induces osteogenic differentiation of bone mesenchymal stem cells in treating AIONFH.

Sox10 is required for systemic initiation of bone mineralization

Heterozygous variants in SOX10 cause congenital syndromes affecting pigmentation, digestion, hearing, and neural development, primarily attributable to failed differentiation or loss of non-skeletal neural crest derivatives. We report here an additional, previously undescribed requirement for Sox10 in bone mineralization. Neither crest- nor mesoderm-derived bones initiate mineralization on time in zebrafish sox10 mutants, despite normal osteoblast differentiation and matrix production. Mutants are deficient in the Trpv6+ ionocytes that take up calcium from the environment, resulting in severe calcium deficiency. As these ionocytes derive from ectoderm, not crest, we hypothesized that the primary defect resides in a separate organ that systemically regulates ionocyte numbers. RNA sequencing revealed significantly elevated stanniocalcin (Stc1a), an anti-hypercalcemic hormone, in sox10 mutants. Stc1a inhibits calcium uptake in fish by repressing trpv6 expression and Trpv6+ ionocyte proliferation. Epistasis assays confirm excess Stc1a as the proximate cause of the calcium deficit. The pronephros-derived glands that synthesize Stc1a interact with sox10+ cells, but these cells are missing in mutants. We conclude that sox10+ crest-derived cells non-autonomously limit Stc1a production to allow the inaugural wave of calcium uptake necessary to initiate bone mineralization.

The effect of LARP7 on gene expression during osteogenesis

BACKGROUND

La-related protein 7 (LARP7) is a key regulator of RNA metabolism and is thought to play a role in various cellular processes. LARP7 gene autosomal recessive mutations are the cause of Alazami syndrome, which presents with skeletal abnormalities, intellectual disabilities, and facial dysmorphisms. This study aimed to determine the role of LARP7 in modulating gene expression dynamics during osteogenesis.

METHODS AND RESULTS

First, the temporal expression profile of the LARP7 gene during various stages of osteogenesis was examined. Then, RNA interference-mediated knockdown of LARP7 was implemented and high-throughput RNA-seq analysis was performed in order to identify global gene expression changes associated with knockdown of LARP7. The findings show there were significant alterations in the overall gene expression profile. The observed down-regulation in extracellular matrix (ECM) component genes suggests that it might lead to impairments in the structure and function of the bone matrix. Additionally, modulation of alternative splicing events were observed, especially in the RUNX2 and SPP1, indicating the potential contribution of LARP7 to the phenotypic features observed in Alazami syndrome.

CONCLUSION

Overall, the findings clarify the regulatory mechanisms of LARP7 in osteogenic differentiation and illuminate potential avenues for therapeutic interventions in patients with skeletal disorders.

Mapping the spatial atlas of the human bone tissue integrating spatial and single-cell transcriptomics

Bone is a multifaceted tissue requiring orchestrated interplays of diverse cells within specialized microenvironments. Although significant progress has been made in understanding cellular and molecular mechanisms of component cells of bone, revealing their spatial organization and interactions in native bone tissue microenvironment is crucial for advancing precision medicine, as they govern fundamental signaling pathways and functional dependencies among various bone cells. In this study, we present the first integrative high-resolution map of human bone and bone marrow, using spatial and single-cell transcriptomics profiling from femoral tissue. This multi-modal approach discovered a novel bone formation-specialized niche enriched with osteoblastic lineage cells and fibroblasts and unveiled critical cell-cell communications and co-localization patterns between osteoblastic lineage cells and other cells. Furthermore, we discovered a novel spatial gradient of cellular composition, gene expression and signaling pathway activities radiating from the trabecular bone. This comprehensive atlas delineates the intricate bone cellular architecture and illuminates key molecular processes and dependencies among cells that coordinate bone metabolism. In sum, our study provides an essential reference for the field of bone biology and lays the foundation for advanced mechanistic studies and precision medicine approaches in bone-related disorders.

Novel Clinical Insights into the Pathogenesis of Posttraumatic Elbow Stiffness: An Expression Profile Analysis of Contracted Joint Capsule in Human

Background

Posttraumatic elbow stiffness is a complex complication with two characteristics of capsular contracture and heterotopic ossification. Currently, genomic mechanisms and pathogenesis of posttraumatic elbow stiffness remain inadequately understood. This study aims to identify differentially expressed genes (DEGs) and elucidate molecular networks of posttraumatic elbow stiffness, providing novel insights into disease mechanisms at transcriptome level.

Methods

Global transcriptome sequencing was conducted on six capsular samples from individuals with posttraumatic elbow stiffness and three control capsular samples from individuals with elbow fractures. Differentially expressed genes (DEGs), microRNAs, and long non-coding RNAs (LncRNAs) were identified and analyzed. Functional enrichment analysis was performed, and the associated protein-protein interaction (PPI) network was constructed. MicroRNAs targeting these DEGs were identified, and transcription factors (TFs) targeting DEGs were predicted using the ENCODE database. Finally, key DEGs were validated by quantitative real-time polymerase chain reaction (qRT-PCR).

Results

A total of 4909 DEGs associated with protein-coding, LncRNA and microRNA were detected, including 2124 upregulated and 2785 downregulated. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that the DEGs were significantly enriched in 36 signaling pathways, notably involving inflammatory responses and extracellular matrix (ECM) receptor interactions. The protein-protein interaction (PPI) network analysis highlighted genes such as SPP1, IBSP, MMP13 and MYO1A as having higher degrees of connectivity. Key microRNAs (hsa-miR-186-5p, hsa-miR-515-5p, and hsa-miR-590-3p) and transcription factors (TFDP1 and STAT3) were predicted to be implicated in the pathogenesis of posttraumatic elbow stiffness through the microRNA-transcription factor regulatory network analysis.

Conclusion

The study provided insights into the molecular mechanisms underlying the changes in the contracted capsules associated with posttraumatic elbow stiffness. Hub genes including SPP1, IBSP, MMP13, and MYO1A, key microRNAs (has-miR-186-5p, has-miR-515-5p, hsa-miR-590-3p) and TFs (TFDP1 and STAT3) may serve as prognostic and therapeutic targets of posttraumatic elbow stiffness, and provide a new idea for the future research direction of clinical treatment.

Dichotomitin promotes osteoblast differentiation and improves osteoporosis by inhibiting oxidative stress

OBJECTIVE

Osteoporosis is a systemic disease with high morbidity and significant adverse effects. Increasing evidence supports the close relationship between oxidative stress and osteoporosis, suggesting that treatment with antioxidants may be a viable approach. This study evaluated the antioxidant properties of dichotomitin (DH) and its potential protective effects against osteoporosis.

METHODS

SD rats were divided into three groups: Sham, OVX, and OVX + DH (5 mg/kg, intraperitoneal injection twice weekly). After three months, blood samples, femurs, and tibiae were collected for analysis. Micro-CT evaluated the femoral, while histological examination assessed tibial tissues. Serum osteogenic biochemical markers were measured. In vitro, osteogenic differentiation was induced with varying concentrations of DH, followed by ALP and ARS staining. RT-qPCR and western blot were used to assess the expression of osteogenesis-related genes and proteins. Additionally, an oxidative stress cell model was established, dividing cells into control, H2O2-treated, and H2O2 + DH-treated groups. Expression of oxidative stress-related genes and proteins was assessed using real-time quantitative PCR and western blotting.

RESULTS

Micro-CT and histological staining revealed decreased and disrupted bone trabeculae in the OVX group, whereas the DH-treated group exhibited enhanced bone trabecular area and structure compared to the OVX group. In vitro studies showed that DH enhanced ALP activity and elevated expression of RUNX2, OPN, OCN, SOD1, and SOD2.

CONCLUSION

DH has the potential to enhance osteoblast differentiation and alleviate osteoporosis through the attenuation of oxidative stress.

Exploring the Logic and Conducting a Comprehensive Evaluation of the Adiponectin Receptor Agonists AdipoRon and AdipoAI's Impacts on Bone Metabolism and Repair-A Systematic Review

INTRODUCTION

Adiponectin replacement therapy shows promising outcomes in various diseases, especially for bone-related disorders. Challenges in using the complete protein have led to alternative approaches, with AdipoRon and AdipoAI emerging as extensively researched drug candidates. Their influence on models of bone-related disorders has progressed considerably but there has been no review of their effectiveness in modulating bone metabolism and repair.

METHODS

This systematic review seeks to address this knowledge gap. Based on preclinical evidence from PubMed, EMBASE, and COCHRANE, ten studies were included following PRISMA guidelines. The JBI Checklist Critical Appraisal Tool assessed the quality of this systematic review. The studies encompassed various animal models, addressing bone defects, osseointegration, diabetes-associated periodontitis, fracture repair, growth retardation, and diabetes-associated peri-implantitis.

RESULTS

AdipoRon and AdipoAI demonstrated effectiveness in modulating bone metabolism and repair through diverse pathways, including the activation of AdipoR1/APPL1, inhibition of F-actin ring formation, suppression of IκB-α phosphorylation, p65 nuclear translocation and Wnt5a-Ror2 signaling pathway, reduction of CCL2 secretion and expression, regulation of autophagy via LC3A/B expression, modulation of SDF-1 production, activation of the ERK1/2 signaling pathway, modulation of bone integration-related markers and osteokines such as RANKL, BMP-2, OPG, OPN, and Runx2, inhibition of RANKL in osteoblasts, and inhibition of podosome formation via the activation of AMPK.

CONCLUSION

While preclinical studies show promise, human trials are crucial to confirm the clinical safety and effectiveness of AdipoRon and AdipoAI. Caution is necessary due to potential off-target effects, especially in bone therapy with multi-target approaches. Structural biology and computational methods can help predict and understand these effects.

A Multifunctional Cobalt-Containing Implant for Treating Biofilm Infections and Promoting Osteointegration in Infected Bone Defects Through Macrophage-Mediated Immunomodulation

Treating bone infections and ensuring bone recovery is one of the major global problems facing modern orthopedics. Prolonged antibiotic use may increase the risk of antimicrobial resistance, and inflammation caused by biofilms can obstruct tissue healing, making bone infection treatment even more challenging. The optimal treatment strategy combines immune response modification to promote osteogenesis with effective bacterial infection removal that does not require long-term antibiotic use. A one-step plasma immersion ion implantation approach is used to create titanium alloy implants incorporating cobalt. According to experimental findings, cobalt-containing titanium implants exhibit improved antibacterial activity by efficiently disrupting biofilm formations and reducing Methicillin-resistant Staphylococcus aureus adherence by over 80%. Additionally, the implants exhibit superior anti-inflammatory and osseointegration properties. RNA sequencing analysis reveals the potential mechanism of Co2+ in regulating the polarization of macrophages toward the anti-inflammatory M2 phenotype, which is crucial for creating an immune environment conducive to bone healing. Concurrently, these implants promote osteogenic differentiation while suppressing osteoclast activity, further supporting bone repair. Overall, without exogenous recombinant proteins or antibiotics, the implants effectively eradicate infections and expedite bone repair, offering a novel therapeutic strategy for complex skeletal diseases with clinical promise.

Evaluating osteopontin as a biomarker of obesity related complications before and after metabolic and bariatric surgery: A systematic review and meta-analysis

BACKGROUND/OBJECTIVES

Obesity is a major public health concern, significantly elevating the risk of developing comorbid conditions such as type 2 diabetes mellitus and cardio-vascular diseases, while also shortening life expectancy. Currently, metabolic and bariatric surgery (MBS) is one of the most effective long-term interventions for achieving substantial weight loss, alongside notable improvements in overall quality of life. However, evidence suggests that these procedures may negatively affect bone health, leading to an increased risk of fractures. This systematic review and meta-analysis aim to assess the role of Osteopontin (OPN) as a potential biomarker for predicting both persistent inflammation and bone deterioration following MBS.

METHODS

A comprehensive search of scientific databases including PubMed (MEDLINE), Embase (OVID), and Web of Science, covering literature up to January 31, 2024, identified 6 studies that met the inclusion criteria for the systematic review. For the meta-analysis, data from 5 studies measuring circulating OPN levels pre- and post-surgery were pooled.

RESULTS

The combined analysis revealed a significant increase in OPN levels after MBS compared to baseline (OR: 24.56; 95 % CI: 13.30-35.81; p < 0.0001).

CONCLUSIONS

These findings suggest that OPN may serve as a valuable biomarker for monitoring inflammation and assessing the risk of bone-related complications in patients following MBS.

The Biphasic Activity of Auricularia Auricula-Judae Extract on Bone Homeostasis through Inhibition of Osteoclastogenesis and Modulation of Osteogenic Activity

Osteoporosis arises from the disturbance of bone homeostasis, a process regulated by osteoblasts and osteoclasts. The treatment and prevention of bone metabolic disorders resulting from an imbalance in bone homeostasis require the use of agents that effectively promote both bone formation and anti-resorptive effects. Therefore, an investigation was carried out to determine the potential of the edible mushroom Auricularia auricula-judae in modulating bone remodeling by inhibiting RANKL-induced osteoclastogenesis and enhancing BMP-2-stimulated osteoblast differentiation. Moreover, this study assessed the mode of action of the Auricularia auricula-judae extracts. The staining of tartrate-resistant acid phosphatase (TRAP), a marker for osteoclast activity, demonstrated that Auricularia auricula-judae water extract (AAJWE) inhibited the formation of multinucleated osteoclasts while exhibiting no cytotoxic effects. The study demonstrated that AAJWE reduced RANKL-induced osteoclast differentiation by inhibiting c-Fos/NFATc1 through the inhibition of ERK and JNK phosphorylation during the RANKL-induced osteoclast differentiation. Moreover, AAJWE exhibited a dose-dependent induction of ALP expression in the presence of BMP-2 during osteoblast differentiation. The AAJWE strengthened BMP-2-induced osteogenesis through the activation of Runx2 and Smad phosphorylation. Therefore, AAJWE emerges as a promising candidate for both prevention and therapy owing to its biphasic effect, which aids in the preservation of bone homeostasis.

Magnetically responsive micro-clustered calcium phosphate-reinforced cell-laden microbead sodium alginate hydrogel for accelerated osteogenic tissue regeneration

The rising prevalence of bone injuries has increased the demand for minimally invasive treatments. Microbead hydrogels, renowned for cell encapsulation, provide a versatile substrate for bone tissue regeneration. They deliver bioactive agents, support cell growth, and promote osteogenesis, aiding bone repair and regeneration. In this study, we synthesized superparamagnetic iron oxide nanoparticles (Sp) coated with a calcium phosphate layer (m-Sp), achieving a distinctive flower-like micro-cluster morphology. Subsequently, sodium alginate (SA) microbead hydrogels containing m-Sp (McSa@m-Sp) were fabricated using a dropping gelation strategy. McSa@m-Sp is magnetically targetable, enhance cross-linking, control degradation rates, and provide strong antibacterial activity. Encapsulation studies with MC3T3-E1 cells revealed enhanced viability and proliferation. These studies also indicated significantly elevated alkaline phosphatase (ALP) activity and mineralization in MC3T3-E1 cells, as confirmed by Alizarin Red S (ARS) and Von Kossa staining, along with increased collagen production within the McSa@m-Sp microbead hydrogels. Immunocytochemistry (ICC) and gene expression studies supported the osteoinductive potential of McSa@m-Sp, showing increased expression of osteogenic markers including RUNX-2, collagen-I, osteopontin, and osteocalcin. Thus, McSa@m-Sp microbead hydrogels offer a promising strategy for multifunctional scaffolds in bone tissue engineering.

How the bone microenvironment shapes the pre-metastatic niche and metastasis

The bone is a frequent metastatic site, with changes in the mineralized bone and the bone marrow milieu that can also prime other sites for metastasis by educating progenitor cells to support metastatic spread. Stromal and immune populations cooperatively maintain the organizationally complex bone niches and are dysregulated in the presence of a distant primary tumor and metastatic disease. Interrogating the bone niches that facilitate metastatic spread using innovative technologies holds the potential to aid in preventing metastasis in and mediated by the bone. Here, we review recent advances in bone niche biology and its adaptations in the context of cancer.

Fine particulate matter and osteoporosis: evidence, mechanisms, and emerging perspectives

Air pollution, particularly fine particulate matter with an aerodynamic diameter of ≤2.5 μm (PM2.5), has been recognized for its adverse effects on multiple organs beyond the lungs. Among these, the bone began to garner significant attention. This review covers epidemiological, animal, and cell studies on PM2.5 exposure and bone health as well as studies on PM2.5-induced diseases with skeletal complications. Emerging evidence from epidemiological studies indicates a positive association between PM2.5 exposure and the incidence of osteoporosis and fractures, along with a negative association with bone mineral density. Experimental studies have demonstrated that PM2.5 can disrupt the metabolic balance between osteoclasts and osteoblasts through inflammatory responses, oxidative stress, and endocrine disruption, thereby triggering bone loss and osteoporosis. Additionally, this review proposes a secondary mechanism by which PM2.5 may impair bone homeostasis via pathological alterations in other organs, offering new perspectives on the complex interactions between environmental pollutants and bone health. In conclusion, this contemporary review underscores the often-overlooked risk factors of PM2.5 in terms of its adverse effects on bone and elucidates the mechanisms of both primary and secondary toxicity. Further attention should be given to exploring the molecular mechanisms of PM2.5-induced bone impairment and developing effective intervention strategies.

Osteokines in Nonalcoholic Fatty Liver Disease

PURPOSE OF REVIEW

To critically summarize evidence on the potential role of osteokines in the pathogenesis and progression of nonalcoholic fatty liver disease (NAFLD).

RECENT FINDINGS

There are emerging data supporting that certain osteokines, which are specific bone-derived proteins, may beneficially or adversely affect hepatic metabolism, and their alterations in the setting of osteoporosis or other bone metabolic diseases may possibly contribute to the development and progression of NAFLD. There is evidence showing a potential bidirectional association between NAFLD and bone metabolism, which may imply the existence of a liver-bone axis. In this regard, osteocalcin, osteoprotegerin, bone morphogenic protein 4 (BMP4) and BMP6 appear to have a positive impact on the liver, thus possibly alleviating NAFLD, whereas osteopontin, receptor activator of nuclear factor kappa Β ligand (RANKL), sclerostin, periostin, BMP8B, and fibroblast growth factor 23 (FGF23) appear to have a negative impact on the liver, thus possibly exacerbating NAFLD. The potential implication of osteokines in NAFLD warrants further animal and clinical research in the field that may possibly result in novel therapeutic targets for NAFLD in the future.

Evaluation of resveratrol's protective effect on hydrocortisone-induced growth inhibition in the peripubertal rat epiphyseal plate

OBJECTIVE

Chronic use of glucocorticoids during childhood can lead to a decrease in hormone release, including ACTH, GH, TSH, and LH, as well as reduced IGF-1 activity. This can result in osteoporotic changes and hinder growth in height. Resveratrol, an antioxidant with phytoestrogen properties, may improve bone health by increasing bone mineral density in postmenopausal women. It has been shown that resveratrol promotes osteoblastic bone formation and reduces osteoclastic resorption. We aimed to investigate the protective effects of resveratrol on the growth inhibition of the epiphyseal plate induced by hydrocortisone in peripubertal Wistar Albino rats.

METHODS

Rats were randomized into 6 groups and treated with hydrocortisone (10 mg/kg/day) and resveratrol (10-50-100 mg/kg/day) for 10 days after a standard AP tibia radiograph was taken. Blood and tibia bones were collected and evaluated for bone biomarkers (osteopontin, sclerostin), histopathological measures, and apoptosis markers.

RESULTS

Subcutaneous administration of hydrocortisone for 10 days significantly reduced tibia linear growth, as evaluated by radiography (23.4 % vs. 15.1 %, p<0.001). In the group that received 50 mg/kg/day of resveratrol and 10 mg/kg/day of hydrocortisone together, the tibia growth inhibition disappeared both radiographically and histologically. High-dose resveratrol (100 mg/kg/day) significantly reduced plasma sclerostin (p<0.001) and increased osteopontin blood levels (p<0.05) compared to the control group.

CONCLUSION

The inhibitory effect of 10 mg/kg/day hydrocortisone on tibia bone was reversed with 50 mg/kg/day oral resveratrol. Resveratrol's phytoestrogen property is thought to accelerate chondrocyte cellular senescence, counteracting hydrocortisone's inhibitory effect on gonadotropin secretion and senescence.

Enthesitis on Chip - A Model for Studying Acute and Chronic Inflammation of the Enthesis and its Pharmacological Treatment

Enthesitis, the inflammation of the enthesis, which is the point of attachment of tendons and ligaments to bones, is a common musculoskeletal disease. The inflammation often originates from the fibrocartilage region of the enthesis as a consequence of mechanical overuse or -load and consequently tissue damage. During enthesitis, waves of inflammatory cytokines propagate in(to) the fibrocartilage, resulting in detrimental, heterotopic bone formation. Understanding of human enthesitis and its treatment options is limited, also because of lacking in vitro model systems that can closely mimic the pathophysiology of the enthesis and can be used to develop therapies. In this study, an enthes(it)is-on-chip model is developed. On opposite sides of a porous culture membrane separating the chip's two microfluidic compartments, human mesenchymal stromal cells are selectively differentiated into tenocytes and fibrochondrocytes. By introducing an inflammatory cytokine cocktail into the fibrochondrocyte compartment, key aspects of acute and chronic enthesitis, measured as increased expression of inflammatory markers, can be recapitulated. Upon inducing chronic inflammatory conditions, hydroxyapatite deposition, enhanced osteogenic marker expression and reduced secretion of tissue-related extracellular matrix components are observed. Adding the anti-inflammatory drug celecoxib to the fibrochondrocyte compartment mitigates the inflammatory state, demonstrating the potential of the enthesitis-on-chip model for drug testing.

Morin Improves the Bone Histomorphology and Biochemical Markers in an Animal Model of Ovariectomy-Induced Osteoporosis by Suppressing Autophagy and Apoptosis

Osteoporosis (OP) is the most prevalent metabolic bone disease and an important postmenopausal consequence. This study aimed to investigate the effects of morin, a flavonoid with beneficial properties, on ovariectomy-induced OP. Animals were ovariectomized (OVX) and treated with different doses of morin (15, 30, and 45 mg/kg/day) or estradiol (10 μg/kg/day) for 10 weeks by gavage. Then bone histo-stereology, bone-related biochemical indicators, and gene and protein levels of autophagy and apoptosis-related markers were analyzed. In comparison to controls, OVX significantly decreased the number of osteoblasts (5.78 × 106 vs. 1.66 × 106) and osteocytes (32.55 × 106 vs. 11.92 × 106), whereas increasing the number of osteoclasts (83.38 × 103 vs. 392.1 × 103). Moreover, OVX caused a remarkable decrease in bone structures and Ca, P, and estradiol levels while increasing ALP and OC (p < 0.001). The administration of 45 mg/kg/day morin restored the effects of OP on bone histomorphology and biochemical markers (p < 0.05). Further studies revealed that morin caused a 7.1% and 36.6% decrease in the bone level of LC3 and BECN1 proteins, respectively, compared to the OVX group. Also, morin caused a significant decrease of 47.4% in the CASP3 level and a significant increase of 23.6% in the BCL-2 level compared to OVX animals (p < 0.001). The present findings showed that morin is potentially able to improve the bone-related histomorphological and biochemical changes caused by osteoporosis, which is probably attributed to the suppression of apoptosis- and autophagy-caused cell death.

Enhancing bone repair efficiency through synergistic modification of recombinant human collagen onto PLLA membranes

Given the exponential growth of the recombinant human collagen market, it is paramount to devise a robust and straightforward design strategy aimed at preserving the remarkable biological activity of recombinant human collagen while endowing it with tailored mechanical properties and stable morphologies. This innovative approach stands to broaden its applicability in hard tissue repair endeavors. Our study employed a synergistic approach of alkali hydrolysis and Schiff's base chemistry to graft Type I recombinant human collagen (rhCol-I) onto poly (L-lactic acid) (PLLA) membranes, yielding PLLA-rhCol composites. In vitro evaluations substantiated that this reengineered material not only retained the biological efficacy of rhCol-I but also imparted mechanical robustness and processability ideal for bone implant applications. Notably, it exhibited superior tissue engineering attributes, fostering proliferation, adhesion, osteogenic differentiation, mineralization of bone marrow mesenchymal stem cells (BMSCs), and encouraging vascularization. In a rat model of critical-sized bone defects, PLLA-rhCol exhibited markedly enhanced bone repair efficiency over conventional PLLA bone implants, achieving a bone volume fraction (BV/TV) of up to 32.57 ± 3.77 %, while promoting angiogenesis and effectively mitigating inflammatory cell infiltration. This pioneering method of modifying recombinant human collagen onto the side chains of polymeric macromolecules portends broad applicability in enhancing various biocompatible, yet mechanically robust and processable polymers, thereby expanding the horizons of recombinant human collagen utilization in tissue engineering and catering to the ever-evolving market demands.

The Bone-Vascular Axis: A Key Player in Chronic Kidney Disease Associated Vascular Calcification

Background

The bone-vascular axis plays a key role in the pathogenesis of vascular calcification (VC) in patients with chronic kidney disease (CKD). Understanding and managing the role of the bone-vascular axis in CKD-mineral and bone disorder (CKD-MBD) is critical for preventing and treating associated complications, including osteoporosis, arterial calcification, and cardiovascular diseases. This study aimed to comprehensively summarize the role of bone metabolism markers in uremic VC.

Summary

The skeleton, as an endocrine organ, can regulate systemic metabolic processes by secreting various bioactive substances. These molecules can induce the transdifferentiation of vascular smooth muscle cells, promoting their transition to other functional states, thereby affecting vascular growth and remodeling.

Key Messages

The prevalence of VC in individuals with CKD is notably high. CKD-associated VC is characterized by the widespread accumulation of hydroxyapatite within the arterial media, which occurs as a result of the transformation of smooth muscle cells into osteoblastic smooth muscle cells under the influence of uremic toxins. Osteoblasts and osteoclasts in bone tissue secrete mineral metabolic proteins, which can influence neighboring cells, primarily vascular smooth muscle cells, through paracrine signaling. Both circulating and osteocytic sclerostin can exert a protective effect by inhibiting wingless/integrated (WNT)-induced calcification. The therapeutic goal for CKD-MBD is to reduce production of sclerostin by decreasing the osteogenic transdifferentiation of vascular smooth muscle cells. Calciprotein particles act as a physiological agent for delivering calcium-phosphate the bone and inducing fibroblast growth factor-23 expression in osteoblasts.

Protein profile of mouse endolymph suggests a role in controlling cochlear homeostasis

The cochlea contains two extracellular fluids, perilymph and endolymph. Endolymph exhibits high potential of approximately +80 to +110 mV (depending on species), which sensitizes sensory hair cells. Other properties of this unique fluid remain elusive, owing to its minuscule volume in rodent cochlea. We therefore developed a technique to collect high-purity endolymph from mouse cochleae. Comprehensive proteomic analysis of sampled endolymph using liquid chromatography with mass spectrometry identified 301 proteins, dominated by molecules engaged in immunity and proteostasis. Approximately 30% of these proteins were undetectable in our perilymph. A combination of mass spectrometry and different approaches revealed that, compared to perilymph, endolymph was enriched with α2-macroglobulin, osteopontin, apolipoprotein D, apolipoprotein E, and apolipoprotein J/clusterin. In other cells or tissues, α2-macroglobulin, apolipoprotein E, and apolipoprotein J contribute to the clearance of degraded proteins from extracellular fluid. Altogether, with the proteins described here, endolymph may play a protective role in stabilizing cochlear homeostasis.

Osteopontin and Clinical Outcomes in Hemodialysis Patients

BACKGROUND/OBJECTIVES

Chronic kidney disease (CKD) and end-stage kidney disease (ESKD) are significant public health issues, with cardiovascular morbidity and mortality being the leading causes of death in hemodialysis patients. Osteopontin (OPN), a multifunctional glycoprotein, has emerged as a potential biomarker for vascular disease in CKD due to its role in inflammation, tissue remodeling, and calcification.

METHODS

This cohort study included 1124 hemodialysis patients from the PROGREDIRE study, a registry involving 35 dialysis units in Southern Italy. Serum osteopontin levels were measured using enzyme-linked immunosorbent assay (ELISA). The primary endpoints were all-cause and cardiovascular mortality. Multivariate Cox regression analyses were performed to assess the association between osteopontin levels and mortality, adjusting for traditional risk factors, biomarkers of inflammation, nutritional status, and ESKD-related factors.

RESULTS

During a mean follow-up of 2.8 years, 478 patients died, 271 from cardiovascular causes. Independent correlates of osteopontin included alkaline phosphatase and parathyroid hormone. Elevated osteopontin levels were significantly associated with increased all-cause mortality (HR 1.19, 95% CI 1.09-1.31, p < 0.001) and cardiovascular mortality (HR 1.22, 95% CI 1.08-1.38, p = 0.001) after adjusting for confounders.

CONCLUSIONS

Elevated osteopontin levels are associated with increased all-cause and cardiovascular mortality in hemodialysis patients. These findings implicate osteopontin in the high risk for death and cardiovascular disease in the hemodialysis population. Intervention studies are needed to definitively test this hypothesis.

Molecular mechanism of bone metastasis in breast cancer

Bone metastasis is a debilitating complication that frequently occurs in the advanced stages of breast cancer. However, the underlying molecular and cellular mechanisms of the bone metastasis remain unclear. Here, we elucidate how bone metastasis arises from tumor cells that detach from the primary lesions and infiltrate into the surrounding tissue, as well as how these cells disseminate to distant sites. Specifically, we elaborate how tumor cells preferentially grow within the bone micro-environment and interact with bone cells to facilitate bone destruction, characterized as osteoclastic bone metastasis, as well as new bone matrix deposition, characterized as osteoblastic bone metastasis. We also updated the current understanding of the molecular mechanisms underlying bone metastasis and reasons for relapse in breast cancer, and also opportunities of developing novel diagnostic approaches and treatment.

The interplay between osteoarthritis and osteoporosis: Mechanisms, implications, and treatment considerations - A narrative review

This comprehensive review examines the relationship between osteoarthritis (OA) and osteoporosis (OP), two common disorders in the elderly. OA involves joint cartilage degeneration and pain, while OP leads to fractures due to reduced bone mass. Despite different pathologies, both conditions share risk factors such as age and genetics. Studies reveal mixed results: some show higher bone mineral density (BMD) in OA patients, suggesting an inverse relationship, while others find no significant link. Proposed mechanisms include mechanical loading, bone remodeling, and inflammation. Clinical strategies focus on maintaining bone health in OA and monitoring joint health in OP, with treatments like bisphosphonates and exercise. Understanding these interactions is crucial for developing integrated treatments to improve patient outcomes and quality of life. Further research is needed to clarify these complex mechanisms.

Personalized bioceramic grafts for craniomaxillofacial bone regeneration

The reconstruction of craniomaxillofacial bone defects remains clinically challenging. To date, autogenous grafts are considered the gold standard but present critical drawbacks. These shortcomings have driven recent research on craniomaxillofacial bone reconstruction to focus on synthetic grafts with distinct materials and fabrication techniques. Among the various fabrication methods, additive manufacturing (AM) has shown significant clinical potential. AM technologies build three-dimensional (3D) objects with personalized geometry customizable from a computer-aided design. These layer-by-layer 3D biomaterial structures can support bone formation by guiding cell migration/proliferation, osteogenesis, and angiogenesis. Additionally, these structures can be engineered to degrade concomitantly with the new bone tissue formation, making them ideal as synthetic grafts. This review delves into the key advances of bioceramic grafts/scaffolds obtained by 3D printing for personalized craniomaxillofacial bone reconstruction. In this regard, clinically relevant topics such as ceramic-based biomaterials, graft/scaffold characteristics (macro/micro-features), material extrusion-based 3D printing, and the step-by-step workflow to engineer personalized bioceramic grafts are discussed. Importantly, in vitro models are highlighted in conjunction with a thorough examination of the signaling pathways reported when investigating these bioceramics and their effect on cellular response/behavior. Lastly, we summarize the clinical potential and translation opportunities of personalized bioceramics for craniomaxillofacial bone regeneration.