Bone Morphogenetic Protein-2 in Development and Bone Homeostasis

Exploring an innovative augmentation strategy in spinal fusion: A novel selective prostaglandin EP4 receptor agonist as a potential osteopromotive factor to enhance lumbar posterolateral fusion

BACKGROUND

On-site delivery of bioactive agents facilitates enhancing the effectiveness of spinal fusion. However, the FDA-approved agents currently used in clinical practice are limited by side effects and cost issues, urging exploration of new alternatives.

AIM

This study aimed to investigate the effectiveness of KMN-159, a novel selective prostaglandin EP4 receptor agonist with osteopromotive properties, in spinal posterolateral fusion (PLF) surgery.

METHODS

Various doses of KMN-159 were delivered locally using a mineralized collagen matrix (MCM) scaffold, and its efficacy results were compared with FDA-approved recombinant human bone morphogenetic protein-2 (rhBMP-2) in a rat lumbar PLF model. 192 male Wistar rats, aged 10 weeks, were randomized into 8 groups: 1) SHAM, 2) MCM, 3) MCM +10 μg rhBMP-2 (per scaffold), 4-8) MCM + 0.1, 1, 10, 100 or 1000 μg KMN-159 (per scaffold). PLF surgery was performed at the L4-5 level, and animals were euthanized after 3 and 6 weeks for spinal fusion evaluation.

RESULTS

KMN-159 exhibited dose-dependent osteopromotive effects on osteoblasts, osteoclasts, and vascular ingrowth within MCM carriers, resulting in new bone formation in a dose-dependent manner. The mid- and high-dose KMN-159 (10, 100, and 1000 μg) groups significantly enhanced PLF with biomechanical improvement, while low-dose (0.1 and 1 μg) groups were insufficient to achieve lumbar fusion.

CONCLUSION

KMN-159 emerges as a novel osteopromotive factor, coupled with its functionalized MCM scaffold presents a potential bioactive material for enhancing PLF surgery outcomes.

BBPs-functionalized tetrahedral framework nucleic acid hydrogel scaffold captures endogenous BMP-2 to promote bone regeneration

Bone Morphogenetic Protein-2 (BMP-2) is a key growth factor for inducing osteogenic differentiation and promoting bone remodeling. However, the exogenous application of delivery systems for BMP-2 has been hampered by various postoperative complications, poor stability and high price. Hence, in situ enrichment of endogenous BMP-2 is promising. The discovery of a small molecule BMP-2 binding peptide (BBP) that binds specifically to BMP-2 with high affinity lays the foundation for the construction of bioactive materials that capture endogenous BMP-2. In contrast, conventional enrichment strategies have low binding efficiency due to steric hindrance caused by the disordered arrangement of BBPs. Tetrahedral framework nucleic acid (tFNA) exhibits good editability and unique three-dimensional spatial structure that enables topological control of multivalent ligands in spatial distribution. The BBPs are further designed to be stably modified on tFNA (BBPs-tFNA) via click chemistry of the azide-alkyne addition to achieve the orderly arrangement of BBPs in spatial organization, to improve the binding efficiency of BMP-2. Therefore, in this study, BBPs-tFNA is modified on biocompatible hyaluronic acid methacryloyl (HAMA) to construct the functionalized bioactive composite hydrogel scaffolds, with the aim of achieving precise and efficient capture of endogenous BMP-2, stimulating osteogenic differentiation and promoting in situ osteogenesis for bone defect repair.

Biomaterials and therapeutic strategies designed for tooth extraction socket healing

Tooth extraction is the most commonly performed oral surgical procedure, with a wide range of clinical indications. The oral cavity is a complex microenvironment, influenced by oral movements, salivary flow, and bacterial biofilms. These factors can contribute to delayed socket healing and the onset of post-extraction complications, which can burden patients' esthetic and functional rehabilitation. Achieving effective extraction socket healing requires a multidisciplinary approach. Recent advancements in materials science and bioengineering have paved the way for developing novel strategies. This review outlines the fundamental healing processes and cellular-molecular interactions involved in the healing of extraction sockets. It then delves into the current landscape of biomaterials for socket healing, highlighting emerging strategies and potential targets that could transform the treatment paradigm. Building upon this foundation, this review also presents future directions and identifies challenges associated with the clinical application of biomaterials for extraction socket healing.

Notch signaling in osteoblast progenitor cells is required for BMP-induced bone formation

Notch signaling is active during bone formation and prior studies have shown that it is required for both robust intramembranous and endochondral bone regeneration. Particularly, the systemic blockade of Notch signaling has been shown to inhibit BMP-induced bone formation in a murine calvarial defect model. In this study, we genetically disrupted the expression of both the dominant Notch receptor, Jagged-1, and the essential Notch signaling transcription factor Rbpj in osteoblast progenitors during calvarial bone healing. We found that Jagged-1 (and Jagged-2) expression by alpha Smooth Muscle Actin (αSMA) expressing progenitors is required for bone formation. Similarly, we found that Notch transcriptional activity within the αSMA lineage is required for BMP-induced bone regeneration. Inhibition of Notch signaling in the αSMA lineage resulted in decreased osteoblast progenitors, reduced vascularization, and sustained inflammation 10 days post-injury, with enhanced inflammation still present 42 days post-injury. We conclude that Jagged ligand induced Notch signaling within the osteoblast progenitor lineage is therefore required for bone morphogenetic proteins (BMP) induced bone regeneration. Modulation of Notch signaling may represent a new approach to promote bone repair.

Transcriptomic landscape around wound bed defines regenerative versus non-regenerative outcomes in mouse digit amputation

In the mouse distal terminal phalanx (P3), it remains mystery why amputation at less than 33% of the digit results in regeneration, while amputation exceeding 67% leads to non-regeneration. Unraveling the molecular mechanisms underlying this disparity could provide crucial insights for regenerative medicine. In this study, we aim to investigate the tissues within the wound bed to understand the tissue microenvironment associated with regenerative versus non-regenerative outcomes. We employed a P3-specific amputation model in mice, integrated with time-series RNA-seq and a macrophage assay challenged with pro- and anti-inflammatory cytokines, to explore these mechanisms. Our findings revealed that non-regenerative digits exhibit a greater intense early transcriptional response in the wound bed compared to regenerative ones. Furthermore, early macrophage phenotypes differ distinctly between regenerative and non-regenerative outcomes. Regenerative digits also display unique co-expression modules related to Bone Morphogenetic Protein 2 (Bmp2). The differentially expressed genes (DEGs) between regenerative and non-regenerative digits are enriched in targets of several transcription factors, such as HOXA11 and HOXD11 from the HOX gene family, showing a time-dependent pattern of enrichment. These transcription factors, known for their roles in bone regeneration, skeletal patterning, osteoblast activity, fracture healing, angiogenesis, and key signaling pathways, may act as master regulators of the regenerative gene signatures. Additionally, we developed a deep learning AI model capable of predicting post-amputation time and level from RNA-seq data, indicating that the regenerative probability may be "encoded" in the transcriptomic response to amputation.

Advancements in regenerative medicine: a comprehensive review of stem cell and growth factor therapies for osteoarthritis

Osteoarthritis (OA) is a widely encountered degenerative joint disorder marked by gradual cartilage deterioration, inflammation, and pain, which collectively impose considerable strain on global healthcare systems. While traditional therapies typically offer relief from symptoms, they do not tackle the core pathophysiological aspects of the disease. Regenerative medicine has recently risen as a promising field for addressing OA, capitalizing on the regenerative capabilities of stem cells and growth factors to foster tissue healing and renewal. This thorough review delves into the most recent progress in stem cell and growth factor treatments for OA, covering preclinical studies, clinical trials, and novel technological developments. We discuss the diverse origins of stem cells, such as mesenchymal stem cells (MSCs), induced pluripotent stem cells (iPSCs), and adipose-derived stem cells (ASCs), underscoring their therapeutic actions and effectiveness in both preclinical and clinical environments. Moreover, we explore contributions of growth factors like transforming growth factor (TGF)-β, platelet-derived growth factor (PDGF), and insulin-like growth factor (IGF) in modifying OA's pathology and enhancing tissue restoration. Additionally, this review discusses the hurdles and constraints tied to current regenerative strategies, including the standardization of cell sources, the refinement of delivery techniques, and considerations for long-term safety. By meticulously assessing the latest research outcomes and technological breakthroughs, this review aims to shed light on the potential of stem cell and growth factor therapies as forthcoming therapeutic options for OA, thereby propelling forward the domain of regenerative medicine and enhancing clinical results for individuals afflicted with this incapacitating ailment.

Design, synthesis and biological evaluation of new class of pyrazoles-dihydropyrimidinone derivatives as bone anabolic agents

This study explores a series of twenty-four newly synthesized pyrzole-dihydropyrimidinone hybrids as potential bone anabolic agents. Initially, an alkaline phosphatase assay, a common marker of bone formation, was used to screen all compounds for their ability to stimulate osteogenic potential. Initial screening identified three promising candidates (5f, 5u and 5w) that were subsequently confirmed to be non-toxic to osteoblasts. Further investigation revealed that compound 5w displayed the most potent osteoanabolic effect, promoting osteoblast differentiation and upregulating mRNAs expression of osteogenic gene. Based on the promising in vitro and in vivo activity, structure-activity relationship (SAR) analysis revealed a furan ring on the dihydropyrimidinone unit and electron-donating groups on the N-phenyl ring of the pyrazole moiety to be crucial for osteogenic activity. Additionally, molecular docking, favorable pharmacokinetic properties and In silico ADME predictions suggest potential oral bioavailability. These findings establish the pyrazole-dihydropyrimidinone scaffold as a promising hit for developing a new class of orally active bone anabolic agents.

Esculin, a Coumarin Glucoside Prevents Fluoride-Induced Oxidative Stress and Cardiotoxicity in Zebrafish Larvae

Fluoride (F-) is a major groundwater contaminant spread across the world. In excess concentrations, F- can be detrimental to living beings. F- exposure is linked to cellular redox dyshomeostasis, leading to oxidative stress-mediated pathologies including heart dysfunction. Due to its potent antioxidant properties, various phytochemicals are found to alleviate the symptoms of F- toxicity. Hence, we explore the protective effect of esculin (Esc), a coumarin glucoside on F--induced oxidative stress and cardiotoxicity in zebrafish larvae. The experimental groups consisted of NaF (50 ppm) and Esc (100 μM) groups treated alone and in combination with a control group for 6 h. The groups were maintained till 78 hpf after which the level of oxidants (ROS, LPO, and PCC) and antioxidants (GST, GSH, GPx, SOD, and CAT) were assessed. The results revealed that Esc pretreatment restored the depleted antioxidant markers and reduced the levels of oxidant in the Esc+NaF group, exhibiting its antioxidant potential. In addition, analyses of the heartbeat rate and hemoglobin integrity using o-Dianisidine staining were conducted in the control and experimental groups. Esc treatment prevents F- induced cardiac changes including tachycardia and altered blood flow. Further, the mRNA expression level of antioxidant genes (nrf2, gstp1, hmox1a, prdx1, and nqo1) and cardiac developmental genes (bmp2b, nkx2.5, myh6, and myl7) confirmed that Esc acts as a potent free radical scavenger and antioxidant defense enhancer, protecting zebrafish larvae from NaF-induced oxidative stress and heart dysfunction.

Advantage of leaky expression, acid solubilization and CHAPS in the production of cost-effective bone morphogenetic Protein-2

The aim of this study was to purify BMP-2 in an easy and time-efficient way. We have developed a new method in which BMP-2 is produced through leaky expression in E. coli BL21 (DE3) cells as inclusion bodies, eliminating the need for inducer Isopropyl β-D-1-thiogalactopyranoside (IPTG). Inclusion bodies were solubilized by the acid denaturation method. Several refolding agents, along with a reducing and oxidizing environment, were tried to produce a correctly folded dimer, which is the biologically active form of BMP-2. CHAPS was found to be the most effective refolding agent at a concentration of 20 mM. The activity of the purified protein was confirmed by alkaline phosphatase assay and calcium deposition assay on C2C12 cells and native PAGE analysis was done to check binary complex formation upon binding between BMP-2 and ALK-3 receptor. These results demonstrate that the synthesized BMP-2 protein is biologically active and has potential clinical applications.

4-Aminopyridine Promotes BMP2 Expression and Accelerates Tibial Fracture Healing in Mice

BACKGROUND

Delayed bone healing is common in orthopaedic clinical care. Agents that alter cell function to enhance healing would change treatment paradigms. 4-aminopyridine (4-AP) is a U.S. Food and Drug Administration (FDA)-approved drug shown to improve walking in patients with chronic neurological disorders. We recently showed 4-AP's positive effects in the setting of nerve, wound, and even combined multi-tissue limb injury. Here, we directly investigated the effects of 4-AP on bone fracture healing, where differentiation of mesenchymal stem cells into osteoblasts is crucial.

METHODS

All animal experiments conformed to the protocols approved by the Institutional Animal Care and Use Committee at the University of Arizona and Pennsylvania State University. Ten-week-old C57BL/6J male mice (22 to 28 g), following midshaft tibial fracture, were assigned to 4-AP (1.6 mg/kg/day, intraperitoneal [IP]) and saline solution (0.1 mL/mouse/day, IP) treatment groups. Tibiae were harvested on day 21 for micro-computed tomography (CT), 3-point bending tests, and histomorphological analyses. 4-AP's effect on human bone marrow mesenchymal stem cell (hBMSC) and human osteoblast (hOB) cell viability, migration, and proliferation; collagen deposition; matrix mineralization; and bone-forming gene/protein expression analyses was assessed.

RESULTS

4-AP significantly upregulated BMP2 gene and protein expression and gene expression of RUNX2, OSX, BSP, OCN, and OPN in hBMSCs and hOBs. 4-AP significantly enhanced osteoblast migration and proliferation, collagen deposition, and matrix mineralization. Radiographic and micro-CT imaging confirmed 4-AP's benefit versus saline solution treatment in mouse tibial fracture healing (bone mineral density, 687.12 versus 488.29 mg hydroxyapatite/cm3 [p ≤ 0.0021]; bone volume/tissue volume, 0.87 versus 0.72 [p ≤ 0.05]; trabecular number, 7.50 versus 5.78/mm [p ≤ 0.05]; and trabecular thickness, 0.08 versus 0.06 mm [p ≤ 0.05]). Three-point bending tests demonstrated 4-AP's improvement of tibial fracture biomechanical properties versus saline solution (stiffness, 27.93 versus 14.30 N/mm; p ≤ 0.05). 4-AP also increased endogenous BMP2 expression and matrix components in healing callus.

CONCLUSIONS

4-AP increased the healing rate, biomechanical properties, and endogenous BMP2 expression of tibiae following fracture.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

p75 neurotrophin receptor regulates craniofacial growth and morphology in postnatal development

Craniofacial abnormalities are among the most prevalent congenital defects, significantly affecting appearance, function, and quality of life. While the role of genetic mutations in craniofacial malformations is recognized, the underlying molecular mechanisms remain poorly understood. In this study, we investigate the role of p75 neurotrophin receptor (p75NTR) in craniofacial development by comparing wild-type (p75NTR+/+) mice against p75NTR-deficient (p75NTR-/-) knockout mice. We employed histology, micro-CT surface distance, volumetric analysis, and geometric morphometric analysis to assess craniofacial development and growth. On postnatal day 7 (P7), p75NTR-/- mice exhibited reduced skull length compared to wild-type controls. By P28, micro-CT analysis revealed significant reductions in calvarial bone volume and trabecular bone thickness in p75NTR-/- mice. Geometric morphometric analysis identified significant shape alterations in the nasal, parietal, and occipital regions, with p75NTR-/- mice showing a shortened cranium and tapered nasal bone morphology. These findings highlight the critical role of p75NTR in regulating postnatal craniofacial development. Disruption of p75NTR signaling impairs both the growth and morphological integrity of craniofacial structures, which may contribute to the pathogenesis of congenital craniofacial abnormalities. In the future, a better understanding of the molecular mechanisms through which p75NTR mediates craniofacial development may offer valuable insights for future targeted therapeutic strategies for craniofacial defects.

Biological Augmentation Using Electrospun Constructs with Dual Growth Factor Release for Rotator Cuff Repair

Surgical reattachment of tendon to bone is the standard therapy for rotator cuff tear (RCT), but its effectiveness is compromised by retear rates of up to 94%, primarily due to challenges in achieving successful tendon-bone enthesis regeneration under natural conditions. Biological augmentation using biomaterials has emerged as a promising approach to address this challenge. In this study, a bilayer construct incorporates polydopamine (PDA)-mediated bone morphogenetic protein 2 (BMP2) and BMP12 in separate poly(lactic-co-glycolic acid) (PLGA) fiber layers to promote osteoblast and tenocyte growth, respectively, and intermediate fibrocartilage formation, aiming to enhance the regenerative potential of tendon-bone interfaces. The lower layer, consisting of PLGA fibers with BMP2 immobilization through PDA adsorption, significantly accelerated osteoblast growth. Concurrently, the upper BMP12@PLGA-PDA fiber mat facilitated fibrocartilage formation and tendon tissue regeneration, evidenced by significantly elevated tenocyte viability and tenogenic differentiation markers. Therapeutic efficacy assessed through in vivo RCT models demonstrated that the dual-BMP construct augmentation significantly promoted the healing of tendon-bone interfaces, confirmed by biomechanical testing, cartilage immunohistochemistry analysis, and collagen I/II immunohistochemistry analysis. Overall, this combinational strategy, which combines augmentation patches with the controlled release of dual growth factors, shows great promise in improving the overall success rates of rotator cuff repairs.

Advance in candidate genes in mandibular retrognathism: A systematic review

OBJECTIVE

This research aims to dissect the polygenic nature of non-syndromic mandibular retrognathism (MR) and to better understand the genetic underpinnings of MR, with a particular focus on the role of ethnic diversity in influencing genetic predispositions.

METHODS

A comprehensive systematic review was conducted on MR. Electronic databases such as PubMed and Google Scholar were employed, utilizing terms like 'mandibular', 'retrognathism', 'gene', and 'genetic'. This study strictly adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework.

RESULTS

Ten genetic studies were identified that satisfied the eligibility criteria, involving 1010 participants. Variations in candidate genes were reported across different populations, including myosin 1 H (MYO1H), matrilin 1 (MATN1), a disintegrin and metalloproteinase with thrombospondin motifs 9 (ADAMTS9), bone morphogenetic protein 2 (BMP2), parathyroid hormone (PTH), the vitamin-D related genes: vitamin D receptor (VDR), cytochrome P450 family 24 subfamily A member 1 (CYP24A1), and cytochrome P450 family 27 subfamily B member 1 (CYP27B1), collagen type II alpha 1 chain (COL2A1), transforming growth factor-β (TGF-β), TGF-β receptor 2 (TGFBR2), epidermal growth factor (EGF), and EGF receptor gene (EGFR).

CONCLUSION

These findings shed light on the role of genetic factors in MR. Future studies should adopt a multicentric approach to expand sample sizes and enhance the analysis of genetic variants associated with MR.

Novel Ti6Al4V Surface Treatment for Subperiosteal Dental Implants: Evaluation of Osteoblast-like Cell Proliferation and Osteogenic Response

Nowadays, custom-made subperiosteal implants are emerging as a solution in all those cases where there is lack of healthy bone tissue to support endosseous implants. The development of innovative techniques has allowed the production of grids that precisely match the patient's anatomy. Elucidating the impact of laser-melted Ti6Al4V grids on both hard and soft tissues with which they come into contact is, therefore, mandatory. In this study, we analyzed the effects of five different surface treatments on a human osteoblast-like cell line (MG-63). In particular, the cell proliferation and osteogenic response were evaluated. Taken together, our data demonstrate that in our in vitro setting, the new surface treatment developed by Al Ti color could enhance osteogenesis and improve the stabilization of the implant to the residual bone by stimulating the best osteogenic response in MG-63 cells. Although further studies are required to validate our data in an in vivo model, our results provide the basis for future advances in implantology for the long-term maintenance of osseointegration.

The Genetic and Biological Basis of Pseudoarthrosis in Fractures: Current Understanding and Future Directions

Pseudoarthrosis-the failure of normal fracture healing-remains a significant orthopedic challenge affecting approximately 10-15% of long bone fractures, and is associated with significant pain, prolonged disability, and repeated surgical interventions. Despite extensive research into the pathophysiological mechanisms of bone healing, diagnostic approaches remain reliant on clinical findings and radiographic evaluations, with little innovation in tools to predict or diagnose non-union. The present review evaluates the current understanding of the genetic and biological basis of pseudoarthrosis and highlights future research directions. Recent studies have highlighted the potential of specific molecules and genetic markers to serve as predictors of unsuccessful fracture healing. Alterations in mesenchymal stromal cell (MSC) function, including diminished osteogenic potential and increased cellular senescence, are central to pseudoarthrosis pathogenesis. Molecular analyses reveal suppressed bone morphogenetic protein (BMP) signaling and elevated levels of its inhibitors, such as Noggin and Gremlin, which impair bone regeneration. Genetic studies have uncovered polymorphisms in BMP, matrix metalloproteinase (MMP), and Wnt signaling pathways, suggesting a genetic predisposition to non-union. Additionally, the biological differences between atrophic and hypertrophic pseudoarthrosis, including variations in vascularity and inflammatory responses, emphasize the need for targeted approaches to management. Emerging biomarkers, such as circulating microRNAs (miRNAs), cytokine profiles, blood-derived MSCs, and other markers (B7-1 and PlGF-1), have the potential to contribute to early detection of at-risk patients and personalized therapeutic approaches. Advancing our understanding of the genetic and biological underpinnings of pseudoarthrosis is essential for the development of innovative diagnostic tools and therapeutic strategies.

Impact of Low-density Lipoprotein Levels on Rates of Pseudarthrosis After Anterior Cervical Discectomy and Fusion

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To understand how preoperative LDL levels, statin intake, and fish oil intake affect rates of pseudarthrosis after single-level and multilevel ACDF.

SUMMARY OF BACKGROUND DATA

Anterior cervical discectomy and fusion (ACDF) is commonly performed to treat cervical degenerative diseases or injuries causing neck pain, myelopathy, and radiculopathy. Pseudarthrosis following ACDF can lead to persistent symptoms and may require revision surgery. No studies have explored the link between low-density lipoprotein (LDL) levels and statin or fish oil intake on pseudarthrosis in ACDF.

MATERIALS AND METHODS

Patients undergoing ACDF were identified using TriNetX, a health care database with over 100 million patients. Pseudarthrosis rates following single-level and multilevel ACDF were compared between patients with high versus low LDL within one year before surgery. Pseudarthrosis rates were also compared between patients taking or not taking a statin as well as patients taking or not taking fish oil within six months before surgery. For all analyses, patients underwent propensity score matching in a 1:1 ratio based on relevant demographic factors and comorbidities.

RESULTS

Patients with an LDL above 142 mg/dL, compared with below 66 mg/dL, had significantly higher rates of pseudarthrosis at six months, one year, and two years after single-level and multilevel ACDF. Patients not taking a statin or fish oil, compared with those taking a statin or fish oil, respectively, also had significantly higher rates of pseudarthrosis at all time points after multilevel ACDF, but not single-level ACDF.

CONCLUSION

Low LDL levels are associated with reduced rates of pseudarthrosis after single-level and multilevel ACDF. Statin and fish oil intake before surgery are also associated with reduced rates of pseudarthrosis after multilevel, but not single-level ACDF. These associations may be used for preoperative planning, patient optimization, and risk stratification.

The crucial role of beta-catenin in the osteoprotective effect of semaglutide in an ovariectomized rat model of osteoporosis

Postmenopausal osteoporosis is a common chronic medical illness resulting from an imbalance between bone resorption and bone formation along with microarchitecture degeneration attributed to estrogen deficiency and often accompanied by other medical conditions such as weight gain, depression, and insomnia. Semaglutide (SEM) is a recently introduced GLP-1 receptor agonist (GLP-1RA) for the treatment of obesity and type 2 diabetes mellitus by mitigating insulin resistance. It has been discovered that the beneficial effects of GLP-1 are associated with alterations in lipolysis, adipogenesis, and anti-inflammatory processes. GLP-1 analogs transmit signals directly to adipose tissue. Mesenchymal stem cells (MSCs) are multidisciplinary cells that originate from bone marrow, migrate to injury sites, and promote bone regeneration. MSCs can differentiate into osteoblasts, adipose cells, and cartilage cells. Our aim is to investigate the role of semaglutide on bone formation and the Wnt signaling pathway. Osteoporosis was induced in female rats by ovariectomy, and the ovariectomized rats were treated with alendronate as standard treatment with a dose of 3 mg/kg orally and semaglutide with two doses (150 mcg/kg and 300 mcg/kg) S.C. for 10 successive weeks. Semaglutide ameliorates bone detrimental changes induced by ovariectomy. It improves bone microarchitecture and preserves bone mineral content. Semaglutide ameliorates ovariectomy-induced osteoporosis and increases the expression of β-catenin, leading to increased bone formation and halted receptor activator of nuclear factor kappa-Β ligand (RANKL's) activation. Semaglutide can be used as a potential prophylactic and therapeutic drug against osteoporosis, possibly by activating Wnt signaling and decreasing bone resorption.

Mixed-valence vanadium-doped mesoporous bioactive glass for treatment of tumor-associated bone defects

Vanadium is a bioactive trace element with variable valence. Its pentavalent form has been confirmed to be capable of predominantly regulating the early and mid-stage osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) without tumor inhibition, while its tetravalent form exhibits tumor inhibition but only primarily modulates late osteogenic differentiation and angiogenesis. In this study, a multifunctional bone tissue scaffold consisting of mixed-valence vanadium-doped mesoporous bioactive glass and poly(lactic-co-glycolic acid) (V(IV/V)-MBG/PLGA) was developed to simultaneously inhibit the recurrence of osteosarcoma and promote the regeneration of operative bone defects. The in vitro results showed that the V(IV) and V(V) species could be sustainably released from V(IV/V)-MBG and complementarily enhance the proliferation, osteogenic differentiation, and mineralization of BMSCs by activating multiple signaling pathways throughout the whole osteogenesis process. More importantly, the co-existence of mixed-valent vanadium species was able to continuously stimulate the generation of excessive ROS and the depletion of GSH by synergistically supplying an appropriate ratio of V(IV) and V(V) to thermodynamically and kinetically maintain the stable self-circulation of the valence state alteration, thus inducing UMR-106 cell death. In a rat model, V(IV/V)-MBG/PLGA scaffolds effectively suppressed tumor invasion and promoted bone regeneration. These results suggest that V(IV/V)-MBG/PLGA scaffolds are a promising strategy for treating tumor-associated bone defects, offering dual tumor inhibition and bone regeneration.

Biomimetic 3D bioprinted bilayer GelMA scaffolds for the delivery of BMP-2 and VEGF exogenous growth factors to promote vascularized bone regeneration in a calvarial defect model in vivo

The effective treatment of critical-sized bone defects requires a coordinated interaction between osteogenesis and angiogenesis. Inspired by natural bone tissue, we developed a bilayer vascularized bone construct using extrusion-based dual 3D bioprinting. The construct consists of two layers: a bone-mimetic layer, which includes highly methacrylated gelatin (GelMAHIGH), hyaluronic acid, alginate, osteoblast cells, and bone morphogenetic protein-2 (BMP-2) loaded polylactic-co-glycolic acid (PLGA) nanoparticles; and a vessel-mimetic layer, composed of low methacrylated gelatin (GelMALOW), alginate, endothelial cells, and vascular endothelial growth factor (VEGF)-loaded PLGA nanoparticles. These layers were designed to form hierarchical microstructures that enable sustained release of growth factor (GF) thereby stimulating both osteogenic and angiogenic processes. The nanoparticles were synthesized using a microfluidic platform, achieving a narrow size distribution. The hydrogel bioinks were systematically optimized for printability, and it was found that incorporation of nanoparticles improved their mechanical properties, surface roughness, degradability, and GF release profiles. Notably, GF release followed zero-order kinetics, ensuring consistent delivery over time. The bilayer scaffolds demonstrated superior cell proliferation and spreading compared to single-layer scaffolds, and in vivo experiments showed enhanced repair of calvarial bone defects. These findings highlight the significant clinical potential of bilayer scaffolds with sequential GF delivery for treating critical-sized bone defects.

Developing mRNA Nanomedicines with Advanced Targeting Functions

The emerging messenger RNA (mRNA) nanomedicines have sprung up for disease treatment. Developing targeted mRNA nanomedicines has become a thrilling research hotspot in recent years, as they can be precisely delivered to specific organs or tissues to enhance efficiency and avoid side effects. Herein, we give a comprehensive review on the latest research progress of mRNA nanomedicines with targeting functions. mRNA and its carriers are first described in detail. Then, mechanisms of passive targeting, endogenous targeting, and active targeting are outlined, with a focus on various biological barriers that mRNA may encounter during in vivo delivery. Next, emphasis is placed on summarizing mRNA-based organ-targeting strategies. Lastly, the advantages and challenges of mRNA nanomedicines in clinical translation are mentioned. This review is expected to inspire researchers in this field and drive further development of mRNA targeting technology.

dECM and β-TCP incorporation effect on the highly porous injectable bio-glass bead for enhanced bone regeneration: In-vitro, in-vivo insights

This study presents the development of an innovative injectable bioactive material, BG-ETa, for bone regeneration. Porcine-derived dermal extracellular matrix (dECM) was decellularized and combined with beta-tri calcium phosphate (β-TCP) and porous bio-glass (BG) beads, followed by freeze-drying to produce surface-modified BG beads. Incorporating sodium alginate (SA) enhanced injectability of the system, enabling effective delivery to defect sites. Bio-glass promotes osteogenic support and osteogenesis. dECM, rich in essential proteins and growth factors, mimics the bone microenvironment to improve cell adhesion, proliferation, and differentiation. The bioactive dECM/β-TCP coating on the bead surface offers neovascularization and early mineralization properties which ultimately facilitates new bone formation. In vitro assays demonstrated BG-ETa's biocompatibility, antimicrobial properties, and potential for osteogenic differentiation, with significant results in alkaline phosphatase (ALP) activity, alizarin red staining (ARS), immunocytochemistry (ICC), and gene expression through real-time PCR. In vivo implantation in rabbit femoral defects revealed promising degradation and significant bone regeneration after 4 and 8 weeks, as observed by histological analysis and micro-CT imaging. This injectable BG-ETa system holds promise as an effective alternative to traditional grafts, providing bioactive environment for enhanced bone regeneration with the potential to overcome limitations associated with autologous or allogeneic grafting.

Optimizing β-TCP with E-rhBMP-2-infused fibrin for vertical bone regeneration in a mouse calvarium model

Effective reconstruction of large bone defects, particularly in thickness, remains one of the major challenges in orthopedic and dental fields. We previously produced an Escherichia coli-based industrial-scale GMP-grade recombinant human bone morphogenetic protein-2 (E-rhBMP-2) and showed that the combination of E-rhBMP-2 with beta-tricalcium phosphate (β-TCP/E-rhBMP-2) can effectively promote bone reconstruction. However, the limited mechanical strength and poor morphology retention of β-TCP granules are key points that need optimization to obtain more effective grafts and further expand its clinical applications. Therefore, we combined β-TCP/E-rhBMP-2 with fibrin gel to enhance its mechanical properties and usability for vertical bone regeneration. We investigated the mechanical properties and vertical bone regeneration effects of the materials applied, with or without fibrin containing E-rhBMP-2, in a calvarial defect model in mice. Compression tests were conducted to assess the initial stability of the materials. Scanning electron microscopy and Fourier transform infrared spectroscopy were conducted to characterize the presence of fibrin on the scaffold. After 4 and 12 weeks of implantation, micro-computed tomography and histological and immunofluorescent analyses were performed to assess the morphology and volume of the newly formed bone. The fibrin-containing groups had significantly higher initial mechanical strength and higher ability to maintain their morphology in vivo compared to the counterparts without fibrin. However, fibrin gel alone suppressed the bone formation ability of β-TCP/E-rhBMP-2 whereas the presence of high doses of E-rhBMP-2 in fibrin gel resulted in material resorption and enhanced new bone formation. In conclusion, fibrin gel significantly improved the mechanical strength and surgical manageability of the β-TCP/E-rhBMP-2 scaffold, and the addition of E-rhBMP-2 to the fibrin gel further enhanced the vertical bone regeneration and initial structural integrity of the scaffold.

The Clinical Efficacy and Safety of ErhBMP-2/BioCaP/β-TCP as a Novel Bone Substitute Using the Tooth-Extraction-Socket-Healing Model: A Proof-of-Concept Randomized Controlled Trial

AIM

This first randomized controlled trial in humans aimed to assess the efficacy and safety of low-dosage Escherichia coli-derived recombinant human bone morphogenetic protein 2 (ErhBMP-2)-incorporated biomimetic calcium phosphate coating-functionalized β-TCP (ErhBMP-2/BioCaP/β-TCP) as a novel bone substitute using the tooth-extraction-socket-healing model.

MATERIALS AND METHODS

Forty patients requiring dental implants after single-root tooth extraction were enrolled in this study and randomly assigned into three groups: ErhBMP-2/BioCaP/β-TCP (N = 15), β-TCP (N = 15) and natural healing (N = 10). New bone volume density from histomorphometric analyses was evaluated 6 weeks post-operatively as the primary outcome, and other histomorphometric analyses, alveolar bone and soft-tissue changes were the secondary outcomes. Safety parameters included adverse events, soft-tissue healing, oral health impact profile, serum BMP-2 concentrations and other laboratory tests.

RESULTS

The findings revealed a significant increase in new bone volume density in patients treated with ErhBMP-2/BioCaP/β-TCP compared to those receiving β-TCP alone. The required bone augmentation procedures during implant placement surgery in the ErhBMP-2/BioCaP/β-TCP group were significantly less than in the natural healing group. There were no significant differences in safety parameters among the three groups.

CONCLUSION

This clinical trial primarily proved the safety and efficacy of ErhBMP-2/BioCaP/β-TCP as a promising bone substitute.

Light Assisted Covalent Immobilization of Proteins for Biomedical Applications

The covalent immobilization of proteins attracts considerable interest in the biomedical field due to its potential applications in biosensors, recombinant protein purification, and the development of personalized therapeutic carriers. In response to the demand for more cost-effective, time-efficient, and simpler protocols, photo-immobilization emerges as a technique that circumvents the limitations of conventional methods. This approach offers enhanced precision at the nanoscale level and facilitates device reusability, thereby aligning with current sustainability concerns. Photo-immobilization is versatile, as it can be applied to both 2D and 3D substrates. While some methods involve complex protocols using genetically engineered photosensitive linkers, more straightforward techniques rely on amino acid bonds, such as disulfide bonds, for covalent protein bonding. Photo-immobilization can be achieved with both ultraviolet (UV) and visible light. This systematic review examines literature from Scopus, PubMed, and Web of Science, offering insights into relevant studies and considerations for covalent protein immobilization, and presents photochemical approaches applicable to major protein types.

The proneural transcription factor Atoh1 promotes odontogenic differentiation in human dental pulp stem cells (DPSCs)

BACKGROUND

Bioengineering of human teeth for replacement is an appealing regenerative approach in the era of gene therapy. Developmentally regulated transcription factors hold promise in the quest because these transcriptional regulators constitute the gene regulatory networks driving cell fate determination. Atonal homolog 1 (Atoh1) is a transcription factor of the basic helix-loop-helix (bHLH) family essential for neurogenesis in the cerebellum, auditory hair cell differentiation, and intestinal stem cell specification. The functional versatility of Atoh1 prompted us to test the possibility that Atoh1 may intersect the dental pulp stem cell (DPSC) gene regulatory network governing odontogenic differentiation.

METHODS

We isolated DPSCs from human dental pulps and treated the cells with a replication-deficient adenoviral vector to achieve robust ectopic expression of Atoh1, following which the growth and odontogenic differentiation profiles of DPSCs were characterized.

RESULTS

DPSCs harboring the Atoh1 expression vector exhibited an approximately 3,000-fold increase in the expression of Atoh1 compared to the negative control, leading to increased DPSC proliferation in the growth medium (P < 0.05). In the odontogenic medium, Atoh1 caused an early induction of BMP2 (P < 0.001) followed by a late induction of BMP7 (P < 0.01) and increased Wnt signaling (P < 0.01). The increased BMP/Wnt signaling led to up to 8-fold increased expression of the master osteogenic transcription factor Osterix (P < 0.005) while exhibiting no significant effect on Runx2 or Dlx5, which are abundantly expressed in DPSCs. Atoh1 stimulated expression of type I collagen (P < 0.005) and small integrin-binding ligand, N-linked glycoproteins (SIBLINGs) such as bone sialoprotein (P < 0.001), dentin matrix protein 1 (P < 0.05), dentin sialophosphoprotein (P < 0.005), and osteopontin (P < 0.001), resulting in increased dentin matrix mineralization (P < 0.05). The odontogenic phenotype is associated with metabolic remodeling marked by enhanced glycolytic flux and attenuated mitochondrial metabolic enzyme activities.

CONCLUSIONS

Atoh1, despite being a proneural transcription factor in development, possesses a novel odontogenic function upon ectopic expression in DPSCs. This in vitro study demonstrates a novel odontogenic mechanism mediated by ectopic expression of the transcription factor Atoh1 in human DPSCs. The finding may offer an innovative strategy for gene-based regeneration of the pulp-dentin complex.

The Impact of a Human Bone Morphogenetic Protein-infused Nano-Bone Material Combined With Traditional Chinese Medicine Carthamus tinctorius on the Repair of Oral Bone Defects

BACKGROUND

The role of human bone morphogenetic protein-infused in combination with traditional Chinese medicine Carthamus tinctorius in repairing oral bone defects (OBD) was evaluated in this work.

METHODS

An experiment was conducted on a rat OBD model, where rats were randomly rolled into Groups A, B, and C based on their different treatments. Micro-CT was utilized to measure jaw bone volume fraction (BV/TV) and bone mineral density (BMD) in rats, while a biomechanical testing machine assessed compressive strength of the jaw bone. Cell culture technique was employed to measure the osteoblast proliferation rate (PR), and enzyme-linked immunosorbent assay was utilized to detect levels of alkaline phosphatase (ALP), osteocalcin (OCN), tumour necrosis factor-alpha (TNF-α), and interleukin (IL)-6 in the serum.

RESULT

Rats in Groups B and C showed higher jaw bone BV/TV, BMD, compressive strength, osteoblast PR, ALP, and OCN, demonstrating no great differences with Group A (P > .05). TNF-α and IL-6 in Groups B and C were lower in comparison with those in Group A (P > .05). Notably, Groups B and C exhibited statistically obvious differences in jaw bone BV/TV, BMD, osteoblast PR, ALP, OCN, TNF-α, and IL-6 levels (P > .05).

CONCLUSION

The combined application of human bone morphogenetic protein-infused and traditional Chinese medicine C. tinctorius demonstrated positive effects on repair of OBD, reducing inflammatory response and promoting bone tissue repair and formation, thus effectively treating OBD.

Unlocking Osseointegration: Surface Engineering Strategies for Enhanced Dental Implant Integration

Tooth loss is a prevalent problem faced by individuals of all ages across the globe. Various biomaterials, such as metals, bioceramics, polymers, composites of ceramics and polymers, etc., have been used for the manufacturing of dental implants. The success of a dental implant primarily depends on its osseointegration rate. The current surface modification techniques fail to imbibe the basics of tooth development, which can impart better mineralization and osseointegration. This can be improved by developing an understanding of the developmental pathways of dental tissue. Stimulating the correct signaling pathways through inductive material systems can bring about a paradigm shift in dental implant materials. The current review focuses on the developmental pathway and mineralization process that happen during tooth formation and how surface modifications can help in biomimetic mineralization, thereby enhancing osseointegration. We further describe the effect of dental implant surface modifications on mineralization, osteoinduction, and osseointegration; both in vitro and in vivo. The review will help us to understand the natural process of teeth development and mineralization and how the surface properties of dental implants can be further improved to mimic teeth development, in turn increasing osseointegration.

Human bone tissue-derived ECM hydrogels: Controlling physicochemical, biochemical, and biological properties through processing parameters

Decellularized tissues offer significant potential as biological materials for tissue regeneration given their ability to preserve the complex compositions and architecture of the native extracellular matrix (ECM). However, the evaluation and derivation of decellularized matrices from human bone tissue remains largely unexplored. We examined how the physiochemical and biological properties of ECM hydrogels derived from human bone ECM could be controlled by manipulating bone powder size (45-250 μm, 250-1000 μm, and 1000-2000 μm) and ECM composition through modulation of enzyme digestion time (3-5-7 days). A reduction in material bone powder size and an increase in ECM digestion time produced enhanced protein concentrations in the ECM hydrogels, accompanied by the presence of a diverse array of proteins and improved gelation strength. Human bone marrow-derived stromal cells (HBMSCs) cultured on ECM hydrogels from 45 to 250 μm bone powder, over 7 days, demonstrated enhanced osteogenic differentiation compared to hydrogels derived from larger bone powders and collagen gels confirming the potential of the hydrogels as biologically active materials for bone regeneration. Digestion time and bone powder size modulation enabled the generation of hydrogels with enhanced release of ECM proteins and appropriate gelation and rheological properties, offering new opportunities for application in bone repair.

The bone growing concept: A call for a paradigm shift in bone reconstruction

Alveolar bone reconstruction has significantly evolved over the years. The transition from bone transfer techniques to bone regeneration methods aimed to reduce morbidity, increase the available reservoir of bone, and enhance volumetric outcomes. However, current bone regeneration techniques are prolonged and yield suboptimal biological results. This is primarily because the process relies heavily on bone substitutes that lack osteoinductive or osteogenic properties, with the supply of cells and growth factors entirely dependent on endogenous sources. This article calls for a new paradigm shift, proposing a biological approach for more controlled bone growth by the incorporation of exogenous cells and growth factors into a bone-growing process, thereby enhancing biological outcomes over time. Additionally, it presents a biomorphometric clinical algorithm to tailor treatment protocols for various types of bone loss.

Depletion of MicroRNA-100-5p Promotes Osteogenesis Via Lysine(K)-Specific Demethylase 6B

Senescence and osteogenic differentiation potential loss limited bone nonunion treatment effects of bone marrow-derived mesenchymal stem cells (BMSCs). MiR-100-5p/Lysine(K)-specific demethylase 6B (KDM6B) can inhibit osteogenesis, but their effects on bone union remain unclear. This study aims to investigate the effects of miR-100-5p/KDM6B on osteogenic differentiation and bone defects. Wild-type or microRNA 100 (miR-100) knockdown mice underwent critical-size defect (CSD) cranial surgery and collagen I/poly-γ-glutamic acid scaffold treatment. The crania was observed using microcomputed tomography, hematoxylin and eosin staining, Masson staining, alkaline phosphatase (ALP) staining, immunohistochemistry, and immunofluorescence. Primary-cultured BMSCs transfected with miR-100-5p mimic/inhibitor and KDM6B cDNA were evaluated for osteogenic differentiation using Alizarin Red staining, ALP activity detection, and Western blot analysis. Genetic transcription levels were detected using quantitative reverse transcription polymerase chain reaction. This study found that miR-100 depletion promotes defect healing in mouse calvaria, increases the proportion of new bone and osteoblasts in calvaria, and activates the expression of KDM6B and osteocalcin (OCN) proteins, promoting the transcription of bone morphogenetic protein-2, Runt-related transcription factor 2 (Runx2), OCN, and KDM6B, while methylation of lysine 27 on histone H3 (H3K27me3) decreased. Furthermore, miR-100-5p mimics suppressed osteogenic differentiation by inhibiting KDM6B with increased H3K27me3, ALP, Runx2, OCN, and osteopontin protein expression, while miR-100-5p inhibitors have opposite effects. Moreover, KDM6B can reverse miR-100-5p mimic effects. Notably, scaffolds carrying miR-100-5p mimics/inhibitors transfected BMSCs were placed in CSD mice and found that miR-100-5p inhibitors have a better effect on CSD healing and increase new bone without inflammatory cell infiltration. This study proved that miR-100-5p depletion promotes bone union and osteogenic differentiation of BMSCs via KDM6B/H3K27me3.

3D-Printed-Cryogel-Impregnated Functionalized Scaffold Augments Bone Regeneration in Critical Tibia Fracture in Goat

Critical-size bone trauma injuries present a significant clinical challenge because of the limited availability of autografts. In this study, a photocurable composite comprising of polycaprolactone, polypropylene fumarate, and nano-hydroxyapatite (nHAP) (P─P─H) is printed, which shows good osteoconduction in a rat model. A cryogel composed of gelatin-nHAP (GH) is developed to incorporate osteogenic components, specifically bone morphogenetic protein-2 (BMP-2) and zoledronic acid (ZA), termed as GH+B+Z, which is investigated for osteoinductive property in a rat model. Further, a 3D-printed P─P─H scaffold impregnated with GH+B+Z is designed and implanted in a critical-size defect (25 × 10 × 5 mm) in goat tibia. After 4 months, the scaffold is well-integrated with adjacent native bone, with osteoinduction observed in the cryogel-filled region and osteoconduction over the printed scaffold. X-ray radiography and micro-CT analysis showed bone in-growth in the treatment group with 45 ± 1.4% bone volume/tissue volume (BV/TV), while the defect remained unhealed in the control group with BV/TV of 10.5 ± 0.5%. Histology showed significant cell infiltration and matrix deposition over the printed P─P─H scaffold and within the GH cryogel site in the treatment group. Immunohistochemical staining depicted significantly higher normalized collagen I intensity in the treatment group (34.45 ± 2.61%) compared to the control group (4.22 ± 0.78).

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.

Eucommia ulmoides Oliver polysaccharide alleviates glucocorticoid-induced osteoporosis by stimulating bone formation via ERK/BMP-2/SMAD signaling

Osteoporosis (OP) is a metabolic disease characterized by low bone mineral mass owing to osteoblast dysfunction. Eucommia ulmoides Oliver (EuO) is a Chinese herbal medicine traditionally used to treat OP. Here, a polysaccharide purified from the EuO cortex (EuOCP3) was administered to OP mice constructed with dexamethasone (Dex) to investigate its anti-OP activity. EuOCP3 significantly improved Dex-induced bone microarchitecture destruction, increased osteoblast numbers and surface, and stimulated an increase in the expression of osteoblast differentiation markers in the femurs of OP mice. Furthermore, EuOCP3 was applied to MC3T3-E1 cells to further explore its effects on osteoblast differentiation. EuOCP3 significantly promoted osteoblast differentiation and increased the level of phosphorylated extracellular signal-regulated kinase1/2 (ERK1/2) and SMAD1/5/8. The EuOCP3-mediated enhancement of osteoblast differentiation-related proteins and phosphorylated SMAD1/5/8 expression levels was strongly suppressed by an ERK inhibitor (PD98059), which confirmed the critical role of ERK signaling in EuOCP3-induced osteoblast differentiation. In summary, EuOCP3 can stimulate bone formation by improving osteoblast differentiation via ERK/BMP-2/SMAD signaling, indicating the potential use of EuOCP3 as a functional ingredient in food products for anti-OP treatment.

Methyl-Beta-Cyclodextrin Restores Aberrant Bone Morphogenetic Protein 2-Signaling in Bone Marrow Stromal Cells Obtained from Aged C57BL/6 Mice

During aging, disruptions in various signaling pathways become more common. Some older patients will exhibit irregular bone morphogenetic protein (BMP) signaling, which can lead to osteoporosis (OP)-a debilitating bone disease resulting from an imbalance between osteoblasts and osteoclasts. In 2002, the Food and Drug Administration (FDA) approved recombinant human BMP-2 (rhBMP-2) for use in spinal fusion surgeries as it is required for bone formation. However, complications with rhBMP-2 arose and primary osteoblasts from OP patients often fail to respond to BMP-2. Although patient samples are available for study, previous medical histories can impact results. Consequently, the C57BL/6 mouse line serves as a valuable model for studying OP and aging. We find that BMP receptor type Ia (BMPRIa) is upregulated in the bone marrow stromal cells (BMSCs) of 15-month-old mice, consistent with prior data. Furthermore, conjugating BMP-2 with Quantum Dots (QDot®s) allows effective binding to BMPRIa, creating a fluorescent tag for BMP-2. Furthermore, after treating BMSCs with methyl-β-cyclodextrin (MβCD), a disruptor of cellular endocytosis, BMP signaling is restored in 15-month-old mice, as shown by von Kossa assays. MβCD has the potential to restore BMPRIa function, and the BMP signaling pathway offers a promising avenue for future OP therapies.

Surface engineering of orthopedic implants for better clinical adoption

Musculoskeletal disorders are on the rise, and despite advances in alternative materials, treatment for orthopedic conditions still heavily relies on biometal-based implants and scaffolds due to their strength, durability, and biocompatibility in load-bearing applications. Bare metallic implants have been under scrutiny since their introduction, primarily due to their bioinert nature, which results in poor cell-material interaction. This challenge is further intensified by mechanical mismatches that accelerate failure, tribocorrosion-induced material degradation, and bacterial colonization, all contributing to long-term implant failure and posing a significant burden on patient populations. Recent efforts to improve orthopedic medical devices focus on surface engineering strategies that enhance the interaction between cells and materials, creating a biomimetic microenvironment and extending the service life of these implants. This review compiles various physical, chemical, and biological surface engineering approaches currently under research, providing insights into their potential and the challenges associated with their adoption from bench to bedside. Significant emphasis is placed on exploring the future of bioactive coatings, particularly the development of smart coatings like self-healing and drug-eluting coatings, the immunomodulatory effects of functional coatings and biomimetic surfaces to tackle secondary infections, representing the forefront of biomedical surface engineering. The article provides the reader with an overview of the engineering approaches to surface modification of metallic implants, covering both clinical and research perspectives and discussing limitations and future scope.

Open Reduction and Internal Fixation with Bone Morphogenetic Protein-2 for Correction of Nonunion Humeral Shaft Fracture with Pseudoarthrosis in the Geriatric Population: A Case Report

Introduction

Bone morphogenic protein-2 (BMP-2) is a potent growth factor cytokine, with indications for interbody spinal fusion surgery and open tibial shaft repairs due to its osteoinductive properties. Off-label usage of BMP-2 has been documented; however, there are limited studies regarding the efficacy of using BMP-2 in non-union humeral shaft fractures.

Case Report

We present a case of a comminuted left humeral shaft fracture with pseudoarthrosis in a 64-year-old woman. Due to the patient's significant comorbidities, initial fracture management focused on non-surgical intervention with the use of a humeral cuff to correct the fracture. However, the patient's report of persistent and significant pain and serial radiographs indicating poor healing with a non-union fracture prompted surgical intervention. The patient underwent an open reduction and internal fixation (ORIF) with the application of one pledget of BMP-2 at the fracture site to promote osteogenesis. To the best of our knowledge, there is limited information about the efficacy of using BMP-2 for humeral fractures.

Conclusion

Six months following the surgery, radiographs have shown appropriate fracture healing of the left humerus without loosening of hardware and other significant complications. The usage of BMP-2 in this patient has shown to be effective in promoting the healing of her nonunion humeral shaft fracture. Although BMP-2 has typically been FDA indicated for use in lumbar interbody spinal fusion surgery and open tibial shaft repairs, this case demonstrates that BMP-2 can also promote healing of non-union humeral shaft fractures in a safe and effective manner.

Mechanisms of Bone Morphogenetic Protein 2 in Respiratory Diseases

PURPOSE OF REVIEW

Bone morphogenetic protein 2 (BMP2) belongs to the transforming growth factor-β (TGF-β) superfamily and plays an important role in regulating embryonic development, angiogenesis, osteogenic differentiation, tissue homeostasis, and cancer invasion. Increasing studies suggest BMP2 is involved in several respiratory diseases. This study aimed to review the role and mechanisms of BMP2 in respiratory diseases.

RECENT FINDINGS

BMP2 signaling pathway includes the canonical and non-canonical signaling pathway. The canonical signaling pathway is the BMP2-SMAD pathway, and the non-canonical signaling pathway includes mitogen-activated protein kinase (MAPK) pathway and phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathway. The BMP2 is related to pulmonary hypertension (PH), lung cancer, pulmonary fibrosis (PF), asthma, and chronic obstructive pulmonary disease (COPD). BMP2 inhibits the proliferation of pulmonary artery smooth muscle cells (PASMCs), promotes the apoptosis of PASMCs to reduce pulmonary vascular remodeling in PH, which is closely related to the canonical and non-canonical pathway. In addition, BMP2 stimulates the proliferation and migration of cells to promote the occurrence, colonization, and metastasis of lung cancer through the canonical and the non-canonical pathway. Meanwhile, BMP2 exert anti-fibrotic function in PF through canonical signaling pathway. Moreover, BMP2 inhibits airway inflammation to maintain airway homeostasis in asthma. However, the signaling pathways involved in asthma are poorly understood. BMP2 inhibits the expression of ciliary protein and promotes squamous metaplasia of airway epithelial cells to accelerate the development of COPD. In conclusion, BMP2 may be a therapeutic target for several respiratory diseases.

Collagen-Platelet-Rich Plasma Mixed Hydrogels as a pBMP2 Delivery System for Bone Defect Regeneration

Background/Objectives: The replenishment of bone deficiency remains a challenging task in clinical practice. The use of gene-activated matrices (GAMs) impregnated with genetic constructs may be an innovative approach to solving this problem. The aim of this work is to develop collagen-based matrices with the addition of platelet-rich plasma, carrying polyplexes with the BMP2 gene, to study their biocompatibility and osteogenic potential in vitro and in vivo. Methods: The cytocompatibility of the materials during incubation with adipose-derived stem cells (ADSCs) was studied using the MTT test and fluorescent microscopy. Biocompatibility was assessed during intramuscular implantation, followed by histological analysis. Osteogenic differentiation was determined by the expressions of Alpl and Bglap using real-time PCR and extracellular matrix (ECM) mineralization by alizarin red staining. The efficiency of bone regeneration was studied using micro-CT and analysis of histological sections stained according to Masson. Results: After the incubation of ADSCs with GAS, significant increases in the expressions of the Alpl and Bglap genes by 3 ± 0.1 and 9.9 ± 0.6 times, relative to the control, as well as mineralization of the ECM, were observed. The volume of newly formed bone was 37.2 ± 6.2% after implantation of GAS, 20.9 ± 1.2%-non-activated Col/PRP, and 2.6 ± 1.5% in an empty defect. Conclusions: The use of Col/PRP-based matrices is an effective method for delivering of the osteoinductor gene to the site of bone tissue damage. The highest degree of healing was observed after the implantation of Col/PRP-TF/pBMP2 into the critical size defect compared to the other groups.

Calcium phosphate complex of recombinant human thrombomodulin promote bone formation in interbody fusion

Interbody fusion is an orthopedic surgical procedure to connect two adjacent vertebrae in patients suffering from spinal disc disease. The combination of synthetic bone grafts with protein-based drugs is an intriguing approach to stimulate interbody bone growth, specifically in patients exhibiting restricted bone progression. Recombinant human thrombomodulin (rhTM), a novel protein drug characterized by its superior stability and potency, shows promise in enhancing bone formation. A composite bone graft, termed CaP-rhTM, has been synthesized, combining calcium phosphate (CaP) microparticles as a delivery vehicle for rhTM to facilitate interbody fusion.In vitrostudies have demonstrated that rhTM significantly promotes the proliferation and maturation of preosteoblasts at nanogram dosage, while exerting minimal impact on osteosarcoma cell growth. The expression levels of mature osteoblast markers, including osteocalcin, osteopontin, alkaline phosphatase, and calcium deposition were also enhanced by rhTM. In rat caudal disc model of interbody fusion, CaP-rhTM with 800 ng of drug dosage was implanted along with a polylactic acid cage, to ensure structural stability within the intervertebral space. Microcomputed tomography analyses revealed that from 8 to 24 weeks, CaP-rhTM substantially improves both bone volume and trabecular architecture, in addition to the textural integrity of bony endplate surfaces. Histological examination confirmed the formation of a continuous bone bridge connecting adjacent vertebrae. Furthermore, biomechanical assessment via three-point bending tests indicated an improved bone quality of the fused disc. This study has demostrated that rhTM exhibits considerable potential in promoting osteogenesis. The use of CaP-rhTM has also shown significant improvements in promoting interbody fusion.

Sex hormone-binding globulin promotes the osteogenic differentiation potential of equine adipose-derived stromal cells by activating the BMP signaling pathway

Background

Musculoskeletal injuries and chronic degenerative diseases pose significant challenges in equine health, impacting performance and overall well-being. Sex Hormone-Binding Globulin (SHBG) is a glycoprotein determining the bioavailability of sex hormones in the bloodstream, and exerting critical metabolic functions, thus impacting the homeostasis of many tissues including the bone.

Methods

In this study, we investigated the potential role of SHBG in promoting osteogenesis and its underlying mechanisms in a model of equine adipose-derived stromal cells (ASCs). An SHBG-knocked down model has been established using predesigned siRNA, and cells subjected to osteogenic induction medium in the presence of exogenous SHBG protein. Changes in differentiation events where then screened using various analytical methods.

Results

We demonstrated that SHBG treatment enhances the expression of key osteoconductive regulators in equine ASCs CD34+ cells, suggesting its therapeutic potential for bone regeneration. Specifically, SHBG increased the cellular expression of BMP2/4, osteocalcin (OCL), alkaline phosphatase (ALP), and osteopontin (OPN), crucial factors in early osteogenesis. Furthermore, SHBG treatment maintained adequate apoptosis and enhanced autophagy during osteogenic differentiation, contributing to bone formation and remodeling. SHBG further targeted mitochondrial dynamics, and promoted the reorganization of the mitochondrial network, as well as the expression of dynamics mediators including PINK, PARKIN and MFN1, suggesting its role in adapting cells to the osteogenic milieu, with implications for osteoblast maturation and differentiation.

Conclusion

Overall, our findings provide novel insights into SHBG's role in bone formation and suggest its potential therapeutic utility for bone regeneration in equine medicine.

Distribution of Immunomodulation, Protection and Regeneration Factors in Cleft-Affected Bone and Cartilage

BACKGROUND

Craniofacial clefts can form a significant defect within bone and cartilage, which can negatively affect tissue homeostasis and the remodeling process. Multiple proteins can affect supportive tissue growth, while also regulating local immune response and tissue protection. Some of these factors, like galectin-10 (Gal-10), nuclear factor kappa-light-chain-enhancer of activated B cells protein 65 (NF-κB p65), heat shock protein 60 (HSP60) and 70 (HSP70) and cathelicidin (LL-37), have not been well studied in cleft-affected supportive tissue, while more known tissue regeneration regulators like type I collagen (Col-I) and bone morphogenetic proteins 2 and 4 (BMP-2/4) have not been assessed jointly with immunomodulation and protective proteins. Information about the presence and interaction of these proteins in cleft-affected supportive tissue could be helpful in developing biomaterials and improving cleft treatment.

METHODS

Two control groups and two cleft patient groups for bone tissue and cartilage, respectively, were organized with five patients in each group. Immunohistochemistry with the semiquantitative counting method was implemented to determine Gal-10-, NF-κB p65-, HSP60-, HSP70-, LL-37-, Col-I- and BMP-2/4-positive cells within the tissue.

RESULTS

Factor-positive cells were identified in each study group. Multiple statistically significant correlations were identified.

CONCLUSIONS

A significant increase in HSP70-positive chondrocytes in cleft patients could indicate that HSP70 might be reacting to stressors caused by the local tissue defect. A significant increase in Col-I-positive osteocytes in cleft patients might indicate increased bone remodeling and osteocyte activity due to the presence of a cleft. Correlations between factors indicate notable differences in molecular interactions within each group.

A systematic scoping review of the latest data on orthobiologics in the surgical treatment of non-union

INTRODUCTION

Recent studies have shown a growing concern regarding the cost-effectiveness and the lack of supporting data for the biologic agents that are being increasingly used in the orthopedic field. Our aim was to conduct a systematic scoping review of recent publications (last five years) on the use of orthobiologics to treat fracture non-union and summarize the latest available data.

PATIENTS AND METHODS

The inclusion criteria for this review were articles published in English, from 2016 to 2022, and focusing on the use of orthobiologics for the surgical treatment of non-union. Searches were conducted in March 2023 using Pubmed/MEDLINE and Embase. Studies on spinal fusion or gene therapy were excluded. Reviews, case reports with five cases or less, conference proceedings, preliminary reports, pediatric or non-human studies were excluded as well.

RESULTS

The search found 1807 articles, 15 were eligible after PRISMA checklist and exclusions. The evidence was heterogenous and there was only one level II RCT. Recent data suggests that bone morphogenic protein (BMP-2) products could be effective for septic and aseptic tibial non-unions. However, the evidence was not conclusive regarding BMP-7, plasma rich platelets (PRP), stem cells or demineralized bone matrix (DBM).

DISCUSSION

Every non-union case is different in terms of bone defect, biology, mechanical stability, surgical technique and host factors, which contributes to the conflicting reports on the efficacy of orthobiologics in the literature. We might never see a level 1, high powered and robust study defining the efficacy, safety profile and cost-effectiveness of such products.

LEVEL OF EVIDENCE

IV.

Catechin and flavonoid glycosides from the Ulmus genus: Exploring their nutritional pharmacology and therapeutic potential in osteoporosis and inflammatory conditions

This review investigates the therapeutic effects of Ulmus species extracts, traditionally used as tea ingredients in East Asia, on bone health and inflammatory conditions. Through the analysis of 9757 studies, narrowing down to 56 pertinent ones, we evaluated the safety and efficacy of Ulmus extracts. The focus was on catechin glycosides (CG) and flavonoid glycosides (FG), key compounds identified for their potential benefits. The research highlights the extracts' role in enhancing bone mineral density (BMD) by stimulating osteoblast activity and suppressing osteoclast differentiation, suggesting a protective effect against osteoporosis. Furthermore, the extracts demonstrated significant anti-inflammatory properties by modulating inflammatory markers and pathways. The findings confirm the historical use of Ulmus extracts in East Asia for health benefits and recommend further exploration into functional foods and nutraceuticals. The review calls for more rigorous research, including clinical trials, to establish optimal use and integration into modern health solutions. It underscores the potential of Ulmus extracts in promoting bone health and managing inflammation, advocating for a bridge between traditional practices and contemporary scientific validation. In conclusion, Ulmus extracts, a material long consumed as tea ingredients in East Asia, exhibit significant potential for improving bone health and reducing inflammation. This review calls for additional research to explore their full therapeutic capabilities, emphasizing the need for optimized extraction methods and clinical trials. It reinforces the importance of bridging traditional knowledge with contemporary scientific approaches to health and dietary solutions, promoting overall wellness.

Osteogenic effect of poly(lactic-co-glycolic acid) microcapsules with different molecular weights encapsulating bone morphogenetic protein 2

OBJECTIVES

This study aimed to explore the effects of bone morphogenetic protein 2 (BMP-2) encapsula-ted in poly(lactic-co-glycolic acid) (PLGA) microcapsules with different molecular weights on the osteogenic ability of osteoblasts.

METHODS

PLGA microcapsules with different molecular weights (12 000, 30 000) encapsulating BMP-2, were prepared using a dual-channel microinjection pump. The morphology and structure of the microcapsules were characterized by optical microscopy and scanning electron microscopy. The sustained-release performance of the microcapsules was characterized by phosphate buffered saline immersion method. The cell compatibility of the microcapsules was detected by the Calcein-AM/PI staining and CCK-8 method. The chemotactic effect of BMP-2-encapsulated microcapsules on MC3T3-E1 cells after 48 h of treatment was detected by the Transwell assay. The alkaline phosphatase activity assay and Alizarin Red S staining were used to characterize the effect of microcapsules on the osteogenic ability of MC3T3-E1 cells.

RESULTS

Both types of microcapsules with different molecular weights exhibited smooth surfaces, as well as uniform and good cell compatibility. The chemotactic effect of the 12 000 microcapsules was outstanding. The 30 000 microcapsules had a longer sustained-release time, and the initial burst release was reduced by approximately 25% compared with the 12 000 microcapsules. In addition, 30 000 microcapsules performed better in long-term osteogenesis induction than 12 000 microcapsules.

CONCLUSIONS

In this study, the release of BMP-2 is regulated by adjusting the molecular weight of PLGA, and the results indicate that 30 000 microcapsules can better induce the long-term osteogenic ability of MC3T3-E1 cells.

Healing of Humerus Non-union Fracture Using Recombinant Human Bone Morphogenetic Protein With Bone Graft Compared to Bone Graft Alone: A Systematic Review and Meta-Analysis

Non-union fractures of the humerus present significant challenges in orthopedic surgery, often requiring advanced treatments to achieve successful bone healing. The study aimed to compare the use of recombinant human bone morphogenetic protein (rhBMP) with bone grafts versus bone grafts alone for treating humerus non-union fractures with regard to healing rate and complications. Six databases, PubMed, ScienceDirect, The Cochrane Library, Scopus, Web of Science, and Google Scholar, were searched for relevant literature using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and studies were selected according to the set eligibility criteria. Quality assessment was performed using the Mixed Methods Appraisal Tool for randomized controlled trials (RCTs) and non-RCTs. Review Manager (RevMan) version 5.4 (2020, The Cochrane Collaboration, London, United Kingdom) was utilized for meta-analysis at a significance level of 0.01. Eighteen research papers were included for qualitative and quantitative analysis. Due to the unavailability of RCTs, data from the two studies were combined. The pooled data from 16 studies for effectiveness regarding union achieved for rhBMP with bone graft versus bone graft alone was 0.65 (95%CI: 0.07-6.38, I2 =67%, p=0.02). For rhBMP-2 and rhBMP-7 with bone graft, the pooled data was 0.09 (95%CI: 0.00-3.63) with high heterogeneity (I2 =88%) and statistically significant differences (p<0.00001). In the sub-group analysis, the pooled data for infection rate was 1.18 (95%CI, 0.37-3.73) with 39% heterogeneity and a non-significant difference (p=0.10). Adding rhBMP to bone grafts may not significantly improve union rates compared to bone graft alone in humerus non-union fractures. However, the trend shows increased infection rates with rhBMP usage. Further high-quality RCTs are warranted to confirm these findings and elucidate the optimal management strategy for humerus non-union fractures.

Interactions between kisspeptin and bone: Cellular mechanisms, clinical evidence, and future potential

The neuropeptide kisspeptin and its cognate receptor have been extensively studied in reproductive physiology, with diverse and well-established functions, including as an upstream regulator of pubertal onset, reproductive hormone secretion, and sexual behavior. Besides classical reproduction, both kisspeptin and its receptor are extensively expressed in bone-resorbing osteoclasts and bone-forming osteoblasts, which putatively permits direct bone effects. Accordingly, this sets the scene for recent compelling findings derived from in vitro experiments through to in vivo and clinical studies revealing prominent regulatory interactions for kisspeptin signaling in bone metabolism, as well as certain oncological aspects of bone metabolism. Herein, we comprehensively examine the experimental evidence obtained to date supporting the interaction between kisspeptin and bone. A comprehensive understanding of this emerging facet of kisspeptin biology is fundamental to exploiting the future therapeutic potential of kisspeptin-based medicines as a novel strategy for treating bone-related disorders.

Molecular Interplay in Cardiac Fibrosis: Exploring the Functions of RUNX2, BMP2, and Notch

Cardiac fibrosis, characterized by the excessive deposition of extracellular matrix proteins, significantly contributes to the morbidity and mortality associated with cardiovascular diseases. This article explores the complex interplay between Runt-related transcription factor 2 (RUNX2), bone morphogenetic protein 2 (BMP2), and Notch signaling pathways in the pathogenesis of cardiac fibrosis. Each of these pathways plays a crucial role in the regulation of cellular functions and interactions that underpin fibrotic processes in the heart. Through a detailed review of current research, we highlight how the crosstalk among RUNX2, BMP2, and Notch not only facilitates our understanding of the fibrotic mechanisms but also points to potential biomolecular targets for intervention. This article delves into the regulatory networks, identifies key molecular mediators, and discusses the implications of these signaling pathways in cardiac structural remodeling. By synthesizing findings from recent studies, we provide insights into the cellular and molecular mechanisms that could guide future research directions, aiming to uncover new therapeutic strategies to manage and treat cardiac fibrosis effectively.

The Role of Bovine Amniotic Membrane and Hydroxyapatite for the Ridge Preservation

Ridge preservation is an important technique for maintaining the dimensions of the alveolar bone following tooth extraction, which is crucial for successful tooth rehabilitation. The combination of bovine amniotic membrane and hydroxyapatite has shown promise as a scaffold material containing growth factors that can stimulate osteogenic-related factors such as bone morphogenetic protein 2 (BMP2), Runt-related transcription factor 2 (RUNX2), and osteocalcin. This stimulation leads to collagen production and osteoblast proliferation, resulting in new bone formation. In this study, bovine amniotic membrane-hydroxyapatite (BAM-HA) composites were prepared using three different ratios of bovine amniotic membrane and hydroxyapatite (2 : 3, 3 : 7, 7 : 13). Thirty Sprague-Dawley rats had their first incisors extracted, and different types of BAM-HA were applied for ridge preservation. The control group received no treatment, while the positive control group was given xenograft. After 14 and 28 days, the animals were sacrificed, and immunohistochemical analysis was performed to evaluate the expression of BMP2, RUNX2, and osteocalcin. Additionally, a histological examination was conducted to analyse collagen thickness and osteoblast cell proliferation. The results demonstrated that the application of BAM-HA significantly increased collagen density, osteoblast cell proliferation, and the expression of BMP2, RUNX2, and osteoclacin compared to the control group (p < 0.05) on both days 14 and 28. Furthermore, increasing the hydroxyapatite content in the composite was found to enhance collagen thickness, osteoblast cell proliferation, and the expression of osteogenic-related factors. These preliminary findings suggest that the combination of BAM-HA can be used for ridge preservation to prevent further bone resorption following tooth extraction.

Investigating the Promising P28 Peptide-Loaded Chitosan/Ceramic Bone Scaffolds for Bone Regeneration

Bone has the ability to heal itself; however, bone defects fail to heal once the damage exceeds a critical size. Bone regeneration remains a significant clinical challenge, with autograft considered the ideal bone graft material due to its sufficient porosity, osteogenic cells, and biological growth factors. However, limitations to bone grafting, such as limited bone stock and high resorption rates, have led to a great deal of research into developing bone graft substitutes. The P28 peptide is a small molecule bioactive biomimetic alternative to mimic the bone morphogenetic protein 2 (BMP-2). In this study, we investigated the potential of P28-loaded hybrid scaffolds to mimic the natural bone structure for enhancing the bone regeneration process. We hypothesized that the peptide-loaded scaffolds and nude scaffolds both have the potential to promote bone healing, and the bone healing process is accelerated by the release of the peptide. To verify our hypothesis, C2C12 cells were evaluated for the presence of calcium deposits by histological stain at 7 and 14 days in cultures with hybrid scaffolds. Total RNA was isolated from C2C12 cells cultured with hybrid scaffolds for 7 and 14 days to assess osteoblast differentiation. The project findings demonstrated that the hybrid scaffold could enhance osteoblast differentiation and significantly improve the therapeutic effects of the scaffold in bone regeneration.

Mild Thermotherapy-Assisted GelMA/HA/MPDA@Roxadustat 3D-Printed Scaffolds with Combined Angiogenesis-Osteogenesis Functions for Bone Regeneration

Early reconstruction of the vascular network is a prerequisite to the effective treatment of substantial bone defects. Traditional 3D printed tissue engineering scaffolds designed to repair large bone defects do not effectively regenerate the vascular network, and rely only on the porous structure within the scaffold for nutrient transfer and metabolic waste removal. This leads to delayed bone restoration and hence functional recovery. Therefore, strategies for generation scaffolds with the capacity to efficiently regenerate vascularization should be developed. This study loads roxarestat (RD), which can stabilize HIF-1α expression in a normoxic environment, onto the mesopore polydopamine nanoparticles (MPDA@RD) to enhance the reconstruction of vascular network in large bone defects. Subsequently, MPDA@RD is mixed with GelMA/HA hydrogel bioink to fabricate a multifunctional hydrogel scaffold (GHM@RD) through 3D printing. In vitro results show that the GHM@RD scaffolds achieve good angiogenic-osteogenic coupling by activating the PI3K/AKT/HSP90 pathway in BMSCs and the PI3K/AKT/HIF-1α pathway in HUVECs under mild thermotherapy. In vivo experiments reveal that RD and mild hyperthermia synergistically induce early vascularization and bone regeneration of critical bone defects. In conclusion, the designed GHM@RD drug delivery scaffold with mild hyperthermia holds great therapeutic value for future treatment of large bone defects.