Bone Morphogenetic Protein-2 in Development and Bone Homeostasis

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.

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.

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.

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.

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.

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.

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.

Evaluation of Integrity of Allogeneic Bone Processed with High Hydrostatic Pressure: A Pilot Animal Study

Processing of bone allografts with strong acids and γ-sterilization results in decreased biomechanical properties and reduction in osteogenecity and osteoconductivity. High hydrostatic pressure (HHP) treatment could be a gentle alternative to processing techniques usually applied. HHP is known to induce devitalization of cancellous bone while preserving biomechanical stability and molecules that induce cell differentiation. Here, a specific HHP protocol for devitalization of cancellous bone was applied to rabbit femoral bone. Allogeneic bone cylinders were subsequently implanted into a defect in the lateral condyles of rabbit femora and were compared to autologous bone grafts. Analysis of bone integration 4 and 12 weeks postoperatively revealed no differences between autografts and HHP-treated allografts regarding the expression of genes characteristic for bone remodeling, showing expression niveous comparable to original bone cylinder. Furthermore, biomechanical properties were evaluated 12 weeks postoperatively. Autografts and HHP-treated allografts both showed a yield strength ranging between 2 and 2.5 MPa and an average bone mass density of 250 mg/cm2. Furthermore, histological analysis of the region of interest revealed a rate of 5 to 10% BPM-2 and approximately 40% osteocalcin-positive staining, with no marked differences between allografts and autografts demonstrating comparable matrix deposition in the graft region. A suitable graft integrity was pointed out by μCT imaging in both groups, supporting the biomechanical data. In summary, the integrity of HHP-treated cancellous bone allografts showed similar results to untreated autografts. Hence, HHP treatment may represent a gentle and effective alternative to existing processing techniques for bone allografts.

Comparative analysis of vision transformers and convolutional neural networks in osteoporosis detection from X-ray images

Within the scope of this investigation, we carried out experiments to investigate the potential of the Vision Transformer (ViT) in the field of medical image analysis. The diagnosis of osteoporosis through inspection of X-ray radio-images is a substantial classification problem that we were able to address with the assistance of Vision Transformer models. In order to provide a basis for comparison, we conducted a parallel analysis in which we sought to solve the same problem by employing traditional convolutional neural networks (CNNs), which are well-known and commonly used techniques for the solution of image categorization issues. The findings of our research led us to conclude that ViT is capable of achieving superior outcomes compared to CNN. Furthermore, provided that methods have access to a sufficient quantity of training data, the probability increases that both methods arrive at more appropriate solutions to critical issues.

Biomimetic Marine-Sponge-Derived Spicule-Microparticle-Mediated Biomineralization and YAP/TAZ Pathway for Bone Regeneration In Vivo

Marine-sponge-derived spicule microparticles (SPMs) possess unique structural and compositional features suitable for bone tissue engineering. However, significant challenges remain in establishing their osteogenic mechanism and practical application in animal models. This study explores the biomimetic potential of SPM in orchestrating biomineralization behavior and modulating the Yes-associated protein 1/transcriptional coactivator with PDZ-binding motif (YAP/TAZ) pathway both in vitro and in vivo. Characterization of SPM revealed a structure comprising amorphous silica oxide mixed with collagen and trace amounts of calcium and phosphate ions, which have the potential to facilitate biomineralization. Structural analysis indicated dynamic biomineralization from SPM to hydroxyapatite, contributing to both in vitro and in vivo osteoconductions. In vitro assessment demonstrated dose-dependent increases in osteogenic gene expression and bone morphogenetic protein-2 protein in response to SPM. In addition, focal adhesion mediated by silica diatoms induced cell spreading on the surface of SPM, leading to cell alignment in the direction of SPM. Mechanical signals from SPM subsequently increased the expression of YAP/TAZ, thereby inducing osteogenic mechanotransduction. The osteogenic activity of SPM-reinforced injectable hydrogel was evaluated in a mouse calvaria defect model, demonstrating rapid vascularized bone regeneration. These findings suggest that biomimetic SPM holds significant promise for regenerating bone tissue.

The Categorization of Perinatal Derivatives for Orthopedic Applications

Musculoskeletal (MSK) pathology encompasses an array of conditions that can cause anything from mild discomfort to permanent injury. Their prevalence and impact on disability have sparked interest in more effective treatments, particularly within orthopedics. As a result, the human placenta has come into focus within regenerative medicine as a perinatal derivative (PnD). These biologics are sourced from components of the placenta, each possessing a unique composition of collagens, proteins, and factors believed to aid in healing and regeneration. This review aims to explore the current literature on PnD biologics and their potential benefits for treating various MSK pathologies. We delve into different types of PnDs and their healing effects on muscles, tendons, bones, cartilage, ligaments, and nerves. Our discussions highlight the crucial role of immune modulation in the healing process for each condition. PnDs have been observed to influence the balance between anti- and pro-inflammatory factors and, in some cases, act as biologic scaffolds for tissue growth. Additionally, we assess the range of PnDs available, while also addressing gaps in our understanding, particularly regarding biologic processing methods. Although certain PnD biologics have varying levels of support in orthopedic literature, further clinical investigations are necessary to fully evaluate their impact on human patients.

Prmt7 is required for the osteogenic differentiation of mesenchymal stem cells via modulation of BMP signaling

Arginine methylation, which is catalyzed by protein arginine methyltransferases (Prmts), is known to play a key role in various biological processes. However, the function of Prmts in osteogenic differentiation of mesenchymal stem cells (MSCs) has not been clearly understood. In the current study, we attempted to elucidate a positive role of Prmt7 in osteogenic differentiation. Prmt7-depleted C3H/10T1/2 cells or bone marrow mesenchymal stem cells (BMSCs) showed the attenuated expression of osteogenic specific genes and Alizarin red staining compared to the wild-type cells. Furthermore, we found that Prmt7 deficiency reduced the activation of bone morphogenetic protein (BMP) signaling cascade, which is essential for the regulation of cell fate commitment and osteogenesis. Taken together, our data indicate that Prmt7 plays important regulatory roles in osteogenic differentiation. [BMB Reports 2024; 57(7): 330-335].

Harnessing the potential of hydrogels for advanced therapeutic applications: current achievements and future directions

The applications of hydrogels have expanded significantly due to their versatile, highly tunable properties and breakthroughs in biomaterial technologies. In this review, we cover the major achievements and the potential of hydrogels in therapeutic applications, focusing primarily on two areas: emerging cell-based therapies and promising non-cell therapeutic modalities. Within the context of cell therapy, we discuss the capacity of hydrogels to overcome the existing translational challenges faced by mainstream cell therapy paradigms, provide a detailed discussion on the advantages and principal design considerations of hydrogels for boosting the efficacy of cell therapy, as well as list specific examples of their applications in different disease scenarios. We then explore the potential of hydrogels in drug delivery, physical intervention therapies, and other non-cell therapeutic areas (e.g., bioadhesives, artificial tissues, and biosensors), emphasizing their utility beyond mere delivery vehicles. Additionally, we complement our discussion on the latest progress and challenges in the clinical application of hydrogels and outline future research directions, particularly in terms of integration with advanced biomanufacturing technologies. This review aims to present a comprehensive view and critical insights into the design and selection of hydrogels for both cell therapy and non-cell therapies, tailored to meet the therapeutic requirements of diverse diseases and situations.

The effect of favipiravir on fracture healing

The aim of this study was to evaluate the effects of favipiravir on fracture healing. Forty-eight female rats which had a femur fracture with intramedullary Kirschner wire fixation performed were divided into 6 groups; 2 control groups (C1, C2) and 4 experimental groups (F1, F2, F3, F4). The control groups (C1, C2) received physiological saline by oral gavage for 14 days. Two of the experimental groups (F1, F2) received favipiravir by oral gavage for 5 days, whereas the other groups (F3, F4) received it for 14 days. C1, F1 and F3 groups were sacrificed and evaluated on the 14th day, and C2, F2 and F4 groups were sacrificed and evaluated on the 28th day. The fracture sites were assessed for healing radiologically using the Lane and Sandhu scoring system, and assessed histologically using the Huo et al. scoring system. There was no difference between the groups regarding radiological and histological evaluations made on the 14th day (P > .05, P=.216, respectively). On the 28th day, the radiological scores were found to be significantly higher in the control group when compared to the experimental groups (P < .05). Histologically, the control group demonstrated better fracture healing than the groups that had favipiravir administered (P < .001). This study has shown that favipiravir can have negative effects on fracture healing both radiologically and histologically.

In silico assessment of biocompatibility and toxicity: molecular docking and dynamics simulation of PMMA-based dental materials for interim prosthetic restorations

AIM

This study aimed to comprehensively assess the biocompatibility and toxicity profiles of poly(methyl methacrylate) (PMMA) and its monomeric unit, methyl methacrylate (MMA), crucial components in dental materials for interim prosthetic restorations.

METHODOLOGY

Molecular docking was employed to predict the binding affinities, energetics, and steric features of MMA and PMMA with selected receptors involved in bone metabolism and tissue development, including RANKL, Fibronectin, BMP9, NOTCH2, and other related receptors. The HADDOCK standalone version was utilized for docking calculations, employing a Lamarckian genetic algorithm to explore the conformational space of ligand-receptor interactions. Furthermore, molecular dynamics (MD) simulations over 100 nanoseconds were conducted using the GROMACS package to evaluate dynamic actions and structural stability. The LigandScout was utilized for pharmacophore modeling, which employs a shape-based screening approach to identify potential ligand binding sites on protein targets.

RESULTS

The molecular docking studies elucidated promising interactions between PMMA and MMA with key biomolecular targets relevant to dental applications. MD simulation results provided strong evidence supporting the structural stability of PMMA complexes over time. Pharmacophore modeling highlighted the significance of carbonyl and hydroxyl groups as pharmacophoric features, indicating compounds with favorable biocompatibility profiles.

CONCLUSION

This study underscores the potential of PMMA in dental applications, emphasizing its structural stability, molecular interactions, and safety considerations. These findings lay a foundation for future advancements in dental biomaterials, guiding the design and optimization of materials for enhanced biocompatibility. Future directions include experimental validation of computational findings and the development of PMMA-based dental materials with improved biocompatibility and clinical performance.

Co-delivery of rhBMP-2 and zoledronic acid using calcium sulfate/hydroxyapatite carrier as a bioactive bone substitute to enhance and accelerate spinal fusion

Recombinant human bone morphogenetic protein-2 (rhBMP-2) has been FDA-approved for lumbar fusion, but supraphysiologic initial burst release due to suboptimal carrier and late excess bone resorption caused by osteoclast activation have limited its clinical usage. One strategy to mitigate the pro-osteoclast side effect of rhBMP-2 is to give systemic bisphosphonates, but it presents challenges with systemic side effects and low local bioavailability. The aim of this in vivo study was to analyze if posterolateral spinal fusion (PLF) could be improved by utilizing a calcium sulfate/hydroxyapatite (CaS/HA) carrier co-delivering rhBMP-2 and zoledronic acid (ZA). Six groups were allocated (CaS/HA, CaS/HA + BMP-2, CaS/HA + systemic ZA, CaS/HA + local ZA, CaS/HA + BMP-2 + systemic ZA, and CaS/HA + BMP-2 + local ZA). 10-week-old male Wistar rats, were randomly assigned to undergo L4-L5 PLF with implantation of group-dependent scaffolds. At 3 and 6 weeks, the animals were euthanized for radiography, μCT, histological staining, or biomechanical testing to evaluate spinal fusion. The results demonstrated that the CaS/HA biomaterial alone or in combination with local or systemic ZA didn't support PLF. However, the delivery of rhBMP-2 significantly promoted PLF. Combining systemic ZA with BMP-2 didn't enhance spinal fusion. Notably, the co-delivery of rhBMP-2 and ZA using the CaS/HA carrier significantly enhanced and accelerated PLF, without inhibiting systemic bone turnover, and potentially reduced the dose of rhBMP-2. Together, the treatment regimen of CaS/HA biomaterial co-delivering rhBMP-2 and ZA could potentially be a safe and cost-effective off-the-shelf bioactive bone substitute to enhance spinal fusion.

Cbfβ regulates Wnt/β-catenin, Hippo/Yap, and Tgfβ signaling pathways in articular cartilage homeostasis and protects from ACLT surgery-induced osteoarthritis

As the most common degenerative joint disease, osteoarthritis (OA) contributes significantly to pain and disability during aging. Several genes of interest involved in articular cartilage damage in OA have been identified. However, the direct causes of OA are poorly understood. Evaluating the public human RNA-seq dataset showed that CBFB (subunit of a heterodimeric Cbfβ/Runx1, Runx2, or Runx3 complex) expression is decreased in the cartilage of patients with OA. Here, we found that the chondrocyte-specific deletion of Cbfb in tamoxifen-induced Cbfbf/f;Col2a1-CreERT mice caused a spontaneous OA phenotype, worn articular cartilage, increased inflammation, and osteophytes. RNA-sequencing analysis showed that Cbfβ deficiency in articular cartilage resulted in reduced cartilage regeneration, increased canonical Wnt signaling and inflammatory response, and decreased Hippo/Yap signaling and Tgfβ signaling. Immunostaining and western blot validated these RNA-seq analysis results. ACLT surgery-induced OA decreased Cbfβ and Yap expression and increased active β-catenin expression in articular cartilage, while local AAV-mediated Cbfb overexpression promoted Yap expression and diminished active β-catenin expression in OA lesions. Remarkably, AAV-mediated Cbfb overexpression in knee joints of mice with OA showed the significant protective effect of Cbfβ on articular cartilage in the ACLT OA mouse model. Overall, this study, using loss-of-function and gain-of-function approaches, uncovered that low expression of Cbfβ may be the cause of OA. Moreover, Local admission of Cbfb may rescue and protect OA through decreasing Wnt/β-catenin signaling, and increasing Hippo/Yap signaling and Tgfβ/Smad2/3 signaling in OA articular cartilage, indicating that local Cbfb overexpression could be an effective strategy for treatment of OA.

Nonthermal biocompatible plasma in stimulating osteogenic differentiation by targeting p38/ FOXO1 and PI3K/AKT pathways in hBMSCs

Osteoporosis is manifested by decreased bone density and deterioration of bone architecture, increasing the risk of bone fractures Human bone marrow mesenchymal stem cells (hBMSCs)-based tissue engineering serves as a crucial technique for regenerating lost bone and preventing osteoporosis. Non-thermal biocompatible plasma (NBP) is a potential new therapeutic approach employed in several biomedical applications, including regenerative medicine. NBP affects bone remodeling; however, its role in the regulation of osteogenic differentiation in hBMSCs remains largely unexplored. This study aimed to explore the efficiency of NBP in promoting osteogenic differentiation, and the molecular pathways through which these responses occurred in hBMSCs. We found that NBP facilitated osteogenic differentiation through the upregulation of the bone morphogenic protein signal (BMPs) cascade, which in turn induced the expression of p38 and inhibited the forkhead box protein O1 (FOXO1). To further gain insight into the mechanism through which NBP extensively triggers the initiation of osteogenic differentiation in hBMSCs, PI3K/AKT pathway was also analyzed. Overall, these results highlight that NBP enhances osteogenic differentiation in hBMSCs by the stimulation of the p38/FOXO1 through PI3K/AKT signaling pathways. Therefore, the application of NBP in hBMSCs may offer tremendous therapeutic prospects in the treatment of bone regeneration and osteoporosis prevention.

Production and Functional Analysis of Collagen Hexapeptide Repeat Sequences in Pichia pastoris

In the development of biomaterials with specific structural domains associated with various cellular activities, the limited integrin specificity of commonly used adhesion sequences, such as the RGD tripeptide, has resulted in an inability to precisely control cellular responses. To overcome this limitation, we conducted multiple replications of the integrin α2β1-specific ligand, the collagen hexapeptide Gly-Phe-Pro-Gly-Glu-Arg (GFPGER) in Pichia pastoris. This enabled the development of recombinant collagen with high biological activity, which was subsequently expressed, isolated, and purified for structural and functional analysis. The proteins carrying the multiple replications GFPGER sequence demonstrated significant bioactivity in cells, leading to enhanced cell adhesion, osteoblast differentiation, and mineralization when compared to control groups. Importantly, these effects were mediated by integrin α2β1. The new collagen constructed in this study is expected to be a biomaterial for regulating specific cell functions and fates.

Pioneering nanomedicine in orthopedic treatment care: a review of current research and practices

A developing use of nanotechnology in medicine involves using nanoparticles to administer drugs, genes, biologicals, or other materials to targeted cell types, such as cancer cells. In healthcare, nanotechnology has brought about revolutionary changes in the treatment of various medical and surgical conditions, including in orthopedic. Its clinical applications in surgery range from developing surgical instruments and suture materials to enhancing imaging techniques, targeted drug delivery, visualization methods, and wound healing procedures. Notably, nanotechnology plays a significant role in preventing, diagnosing, and treating orthopedic disorders, which is crucial for patients' functional rehabilitation. The integration of nanotechnology improves standards of patient care, fuels research endeavors, facilitates clinical trials, and eventually improves the patient's quality of life. Looking ahead, nanotechnology holds promise for achieving sustained success in numerous surgical disciplines, including orthopedic surgery, in the years to come. This review aims to focus on the application of nanotechnology in orthopedic surgery, highlighting the recent development and future perspective to bridge the bridge for clinical translation.

Bone Regenerative Effect of Injectable Hypoxia Preconditioned Serum-Fibrin (HPS-F) in an Ex Vivo Bone Defect Model

Biofunctionalized hydrogels are widely used in tissue engineering for bone repair. This study examines the bone regenerative effect of the blood-derived growth factor preparation of Hypoxia Preconditioned Serum (HPS) and its fibrin-hydrogel formulation (HPS-F) on drilled defects in embryonic day 19 chick femurs. Measurements of bone-related growth factors in HPS reveal significant elevations of Osteopontin, Osteoprotegerin, and soluble-RANKL compared with normal serum (NS) but no detection of BMP-2/7 or Osteocalcin. Growth factor releases from HPS-F are measurable for at least 7 days. Culturing drilled femurs organotypically on a liquid/gas interface with HPS media supplementation for 10 days demonstrates a 34.6% increase in bone volume and a 52.02% increase in bone mineral density (BMD) within the defect area, which are significantly higher than NS and a basal-media-control, as determined by microcomputed tomography. HPS-F-injected femur defects implanted on a chorioallantoic membrane (CAM) for 7 days exhibit an increase in bone mass of 123.5% and an increase in BMD of 215.2%, which are significantly higher than normal-serum-fibrin (NS-F) and no treatment. Histology reveals calcification, proteoglycan, and collagen fiber deposition in the defect area of HPS-F-treated femurs. Therefore, HPS-F may offer a promising and accessible therapeutic approach to accelerating bone regeneration by a single injection into the bone defect site.

Evaluation of Cardiospermum halicacabum on Bone Morphogenetic Protein-2 (BMP2) mRNA Expression in Osteoblast Cells

Introduction Maintaining bone health is crucial for overall well-being, with osteoblasts playing a vital role in bone formation. Bone morphogenetic protein-2 (BMP2) is a key regulator, stimulating bone matrix synthesis and osteoblast differentiation. Recognizing BMP2's significance, there's growing interest in natural compounds, such as Cardiospermum halicacabum. This study explores Cardiospermum halicacabum's potential influence on BMP2 mRNA expression in osteoblast cells for insights into bone health modulation. Materials and methods  This research utilized Cardiospermum halicacabum to explore its impact on MG-63 cells, a human osteoblast cell line. Osteoblast cells were cultured in Dulbecco's modified Eagle's medium (DMEM), supplemented with 10% heat-inactivated fetal bovine serum, and maintained at 37°C in a 5% CO2 and 95% air environment. Cell viability was evaluated by seeding osteoblast cells into 96-well plates and exposing them to different concentrations of Cardiospermum halicacabum (2.0 μg/ml and 20 μg/ml). The study observed both the promotion of osteoblast cell growth in MG-63 and morphological changes in the cells under an inverted light microscope at 10x magnification. Results were presented using one-way analysis of variance (ANOVA) conducted with IBM SPSS Statistics for Windows, Version 23 (Released 2015; IBM Corp., Armonk, New York, United States). Result The reverse transcription-polymerase chain (RT-PCR) results revealed an increased expression of BMP-2 mRNA fold change in comparison to the control group. A clear positive correlation was observed between the BMP-2 mRNA fold change and the notable increase in the concentration of Cardiospermum halicacabum. This investigation revealed a direct association of BMP-2 mRNA expression with the proliferation of osteoblast cells. Specifically, the BMP-2 mRNA fold change was recorded at 2.26±1.05 in Cardiospermum halicacabum at 2.0 μg/ml and 2.0 ± 0.84 at 20 μg/ml, with corresponding significances of 0.00, respectively. Conclusion  Potential effects of Cardiospermum halicacabum on BMP-2 mRNA expression in osteoblast cells and its role in bone health modulation revealed that Cardiospermum halicacabum may upregulate BMP-2 mRNA expression, suggesting its potential as a natural compound for enhancing bone formation. The observed positive correlation between Cardiospermum halicacabum concentration and BMP-2 mRNA fold change showed the significance of this botanical agent in promoting osteoblast cell proliferation. These results highlight the importance of further research to explore the applications of Cardiospermum halicacabum in managing bone disorders and improving overall bone health.

TRIM21 silencing inhibits the apoptosis and expedites the osteogenic differentiation of dexamethasone‑induced MC3T3‑E1 cells by activating the Keap1/Nrf2 pathway

Steroid-induced osteonecrosis of the femoral head (ONFH) is a serious complication caused by long-term or excessive use of glucocorticoids. The present study aimed to ascertain the effects of tripartite motif-containing protein 21 (TRIM21) on the process of steroid-induced ONFH and its hidden action mechanism. TRIM21 expression in dexamethasone (Dex)-treated mouse MC3T3-E1 preosteoblast cells was examined using reverse transcription-quantitative PCR and western blotting. The Cell Counting Kit-8 (CCK-8) method and lactate dehydrogenase release assay were used to respectively measure cell viability and injury. Flow cytometry analysis was used to assay cell apoptosis. Caspase 3 activity was evaluated using a specific assay, while alkaline phosphatase and Alizarin red S staining were used to evaluate osteogenesis. 2,7-dichloro-dihydrofluorescein diacetate fluorescence probe was used to estimate reactive oxygen species generation. Specific assay kits were used to appraise oxidative stress levels. In addition, the expression of apoptosis-, osteogenic differentiation- and Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2) signaling-associated proteins was assessed using western blotting. In Nrf2 inhibitor (ML385)-pretreated MC3T3-E1 cells exposed to Dex, cell apoptosis, osteogenesis and oxidative stress were detected again as aforementioned. Results revealed that TRIM21 expression was raised in Dex-induced MC3T3-E1 cells and TRIM21 deletion improved the viability and osteogenic differentiation, whereas it hampered the oxidative stress and apoptosis in MC3T3-E1 cells with Dex induction. In addition, silencing of TRIM21 activated Keap1/Nrf2 signaling. Moreover, ML385 partially abrogated the effects of TRIM21 depletion on the oxidative stress, apoptosis and osteogenic differentiation in MC3T3-E1 cells exposed to Dex. In conclusion, TRIM21 silencing might activate Keap1/Nrf2 signaling to protect against steroid-induced ONFH.

Repair of Rat Calvarial Critical-Sized Defects Using Heparin-Conjugated Fibrin Hydrogel Containing BMP-2 and Adipose-Derived Pericytes

The repair of critical-sized calvarial defects is a challenging problem for orthopedic surgery. One of the promising strategies of bone bioengineering to enhance the efficacy of large bone defect regeneration is the combined delivery of stem cells with osteoinductive factors within polymer carriers. The purpose of the research was to study the regenerative effects of heparin-conjugated fibrin (HCF) hydrogel containing bone morphogenetic protein 2 (BMP-2) and adipose-derived pericytes (ADPs) in a rat critical-sized calvarial defect model. In vitro analysis revealed that the HCF hydrogel was able to control the BMP-2 release and induce alkaline phosphatase (ALP) activity in neonatal rat osteoblasts. In addition, it was found that eluted BMP-2 significantly induced the osteogenic differentiation of ADPs. It was characterized by the increased ALP activity, osteocalcin expression and calcium deposits in ADPs. In vivo studies have shown that both HCF hydrogel with BMP-2 and HCF hydrogel with pericytes are able to significantly increase the regeneration of critical-sized calvarial defects in comparison with the control group. Nevertheless, the greatest regenerative effect was found after the co-delivery of ADPs and BMP-2 into a critical-sized calvarial defect. Thus, our findings suggest that the combined delivery of ADPs and BMP-2 in HCF hydrogel holds promise to be applied as an alternative biopolymer for the critical-sized bone defect restoration.

Discovery of a novel homoisoflavonoid derivative 5g for anti-osteoclastic bone loss via targeting FGFR1

Several flavonoids have been shown to exert anti-osteoporosis activity. However, the structure-activity relationship and the mechanism of anti-osteoporosis activity of flavonoids remain unknown. In this study, we prepared a series of novel homoisoflavonoid (HIF) derivatives to evaluate their inhibitory effects on osteoclastogenesis using TRAP-activity in vitro assay. Then, the preliminary structure-activity relationship was studied. Among the evaluated novel flavonoids, derivative 5g exerted the most inhibitory bioactivity on primary osteoclast differentiation without interfering with osteogenesis. It was hence selected for further in vitro, in vivo and mechanism of action investigation. Results show that 5g likely directly binds to the fibroblast growth factor receptor 1 (FGFR1), decreasing the activation of ERK1/2 and IκBα/NF-κB signaling pathways, which in turn blocks osteoclastogenesis in vitro and osteoclastic bone loss in vivo. Our study shows that homoisoflavonoid (HIF) derivatives 5g can serve as a potential novel candidate for treating osteoporosis via inhibition of FGFR1.

Cell-permeable bone morphogenetic protein 2 facilitates bone regeneration by promoting osteogenesis

The use of the FDA-approved osteoinductive growth factor BMP2 is widespread for bone regeneration. However, its clinical application has been hindered by limitations in cell permeability and a short half-life in circulation. To address this issue, we have developed a modified version of BMP2, referred to as Cell Permeable (CP)-BMP2, which possesses improved cell permeability. CP-BMP2 incorporates an advanced macromolecular transduction domain (aMTD) to facilitate transfer across the plasma membrane, a solubilization domain, and recombinant human BMP2. Compared to traditional rhBMP2, CP-BMP2 exhibits enhanced cell permeability, solubility, and bioavailability, and activates Smad phosphorylation through binding to BMP receptor 2. The effectiveness of CP-BMP2 was evaluated in three animal studies focusing on bone regeneration. In the initial study, mice and rabbits with critical-size calvarial defects received subcutaneous (SC) injections of CP-BMP2 and rhBMP2 (7.5 mg/kg, 3 injections per week for 8 weeks).Following 8 weeks of administration, CP-BMP2 demonstrated a remarkable 65 % increase in bone formation in mice when compared to both the vehicle and rhBMP2. Moreover, rabbits exhibited faster bone formation, characterized by a filling pattern originating from the center. In a subsequent study involving injured horses, hind limb bones treated with CP-BMP2 exhibited an 85 % higher bone regeneration rate, as evidenced by Micro-CT results, in contrast to horses treated with the vehicle or rhBMP2 (administered at 150 μg/defect, subcutaneously, once a week for 8 weeks, without a scaffold). These results underscore the potential of CP-BMP2 to facilitate rapid and effective healing. No noticeable adverse effects, such as ectopic bone formation, were observed in any of the studies. Overall, our findings demonstrate that CP-BMP2 holds therapeutic potential as a novel and effective osteogenic agent.

Activation of the BMP2-SMAD1-CGRP pathway in dorsal root ganglia contributes to bone cancer pain in a rat model

Peripheral nerve remodeling and sensitization are involved in cancer-related bone pain. As a member of the transforming growth factor-β class, bone morphogenetic protein 2 (BMP2) is recognized to have a role in the development of the neurological and skeletal systems. Our previous work showed that BMP2 is critical for bone cancer pain (BCP) sensitization. However, the mechanism remains unknown. In the current study, we demonstrated a substantial increase in BMP2 expression in the dorsal root ganglia (DRG) in a rat model of BCP. Knockdown of BMP2 expression ameliorated BCP in rats. Furthermore, the DRG neurons of rats with BCP expressed higher levels of calcitonin gene-related peptide (CGRP), and BCP was successfully suppressed by intrathecal injection of a CGRP receptor blocker (CGRP8-37). Downregulation of BMP2 expression reduced the expression of CGRP in the DRG of rats with BCP and relieved pain behavior. Moreover, we revealed that upregulation of CGRP expression in the DRG may be induced by activation of the BMPR/Smad1 signaling pathway. These findings suggest that BMP2 contributes to BCP by upregulating CGRP in DRG neurons via activating BMPR/Smad1 signaling pathway and that therapeutic targeting of the BMP2-Smad1-CGRP pathway may ameliorate BCP in the context of advanced cancer.

A machine learning algorithm for peripheral artery disease prognosis using biomarker data

Peripheral artery disease (PAD) biomarkers have been studied in isolation; however, an algorithm that considers a protein panel to inform PAD prognosis may improve predictive accuracy. Biomarker-based prediction models were developed and evaluated using a model development (n = 270) and prospective validation cohort (n = 277). Plasma concentrations of 37 proteins were measured at baseline and the patients were followed for 2 years. The primary outcome was 2-year major adverse limb event (MALE; composite of vascular intervention or major amputation). Of the 37 proteins tested, 6 were differentially expressed in patients with vs. without PAD (ADAMTS13, ICAM-1, ANGPTL3, Alpha 1-microglobulin, GDF15, and endostatin). Using 10-fold cross-validation, we developed a random forest machine learning model that accurately predicts 2-year MALE in a prospective validation cohort of PAD patients using a 6-protein panel (AUROC 0.84). This algorithm can support PAD risk stratification, informing clinical decisions on further vascular evaluation and management.

Trends in bioactivity: inducing and detecting mineralization of regenerative polymeric scaffolds

Due to limitations of biological and alloplastic grafts, regenerative engineering has emerged as a promising alternative to treat bone defects. Bioactive polymeric scaffolds are an integral part of such an approach. Bioactivity importantly induces hydroxyapatite mineralization that promotes osteoinductivity and osseointegration with surrounding bone tissue. Strategies to confer bioactivity to polymeric scaffolds utilize bioceramic fillers, coatings and surface treatments, and additives. These approaches can also favorably impact mechanical and degradation properties. A variety of fabrication methods are utilized to prepare scaffolds with requisite morphological features. The bioactivity of scaffolds may be evaluated with a broad set of techniques, including in vitro (acellular and cellular) and in vivo methods. Herein, we highlight contemporary and emerging approaches to prepare and assess scaffold bioactivity, as well as existing challenges.

In Vivo Osteogenic and Angiogenic Properties of a 3D-Printed Isosorbide-Based Gyroid Scaffold Manufactured via Digital Light Processing

INTRODUCTION

Osteogenic and angiogenic properties of synthetic bone grafts play a crucial role in the restoration of bone defects. Angiogenesis is recognised for its support in bone regeneration, particularly in larger defects. The objective of this study is to evaluate the new bone formation and neovascularisation of a 3D-printed isosorbide-based novel CSMA-2 polymer in biomimetic gyroid structures.

METHODS

The gyroid scaffolds were fabricated by 3D printing CSMA-2 polymers with different hydroxyapatite (HA) filler concentrations using the digital light processing (DLP) method. A small animal subcutaneous model and a rat calvaria critical-size defect model were performed to analyse tissue compatibility, angiogenesis, and new bone formation.

RESULTS

The in vivo results showed good biocompatibility of the 3D-printed gyroid scaffolds with no visible prolonged inflammatory reaction. Blood vessels were found to infiltrate the pores from day 7 of the implantation. New bone formation was confirmed with positive MT staining and BMP-2 expression, particularly on scaffolds with 10% HA. Bone volume was significantly higher in the CSMA-2 10HA group compared to the sham control group.

DISCUSSION AND CONCLUSIONS

The results of the subcutaneous model demonstrated a favourable tissue response, including angiogenesis and fibrous tissue, indicative of the early wound healing process. The results from the critical-size defect model showcased new bone formation, as confirmed by micro-CT imaging and immunohistochemistry. The combination of CSMA-2 as the 3D printing material and the gyroid as the 3D structure was found to support essential events in bone healing, specifically angiogenesis and osteogenesis.

Interaction between immuno-stem dual lineages in jaw bone formation and injury repair

The jawbone, a unique structure in the human body, undergoes faster remodeling than other bones due to the presence of stem cells and its distinct immune microenvironment. Long-term exposure of jawbones to an oral environment rich in microbes results in a complex immune balance, as shown by the higher proportion of activated macrophage in the jaw. Stem cells derived from the jawbone have a higher propensity to differentiate into osteoblasts than those derived from other bones. The unique immune microenvironment of the jaw also promotes osteogenic differentiation of jaw stem cells. Here, we summarize the various types of stem cells and immune cells involved in jawbone reconstruction. We describe the mechanism relationship between immune cells and stem cells, including through the production of inflammatory bodies, secretion of cytokines, activation of signaling pathways, etc. In addition, we also comb out cellular interaction of immune cells and stem cells within the jaw under jaw development, homeostasis maintenance and pathological conditions. This review aims to eclucidate the uniqueness of jawbone in the context of stem cell within immune microenvironment, hopefully advancing clinical regeneration of the jawbone.

Glucocorticoids promote steroid-induced osteonecrosis of the femoral head by down-regulating serum alpha-2-macroglobulin to induce oxidative stress and facilitate SIRT2-mediated BMP2 deacetylation

Our study investigated the possible molecular mechanism of glucocorticoid in steroid-induced osteonecrosis of the femoral head (SINFH) through regulating serum alpha-2-macroglobulin and SIRT2-mediated BMP2 deacetylation. Essential genes involved in glucocorticoid-induced SINFH were screened by transcriptome sequencing and analyzed by bioinformatics, followed by identifying downstream regulatory targets. Rat bone marrow mesenchymal stem cells were isolated and treated with methylprednisolone (MP) for in vitro cell experiments. Besides, a glucocorticoid-induced rat ONFH was established using the treatment of MP and LPS. ChIP-PCR detected the enrichment of SIRT2 in the promoter region of BMP2, and the deacetylation modification of SIRT2 on BMP2 was determined. Bioinformatics analysis revealed that glucocorticoids may induce ONFH through the SIRT2/BMP2 axis. In vitro cell experiments showed that glucocorticoids up-regulated SIRT2 expression in BMSCs by inducing oxidative stress, thereby promoting cell apoptosis. The up-regulation of SIRT2 expression may be due to the decreased ability of α2 macroglobulin to inhibit oxidative stress, and the addition of NOX protein inhibitor DPI could significantly inhibit SIRT2 expression. SIRT2 could promote histone deacetylation of the BMP2 promoter and inhibit its expression. In vitro cell experiments further indicated that knocking down SIRT2 could protect BMSC from oxidative stress and cell apoptosis induced by glucocorticoids by promoting BMP2 expression. In addition, animal experiments conducted also demonstrated that the knockdown of SIRT2 could improve glucocorticoid-induced ONFH through up-regulating BMP2 expression. Glucocorticoids could induce oxidative stress by down-regulating serum α2M to promote SIRT2-mediated BMP2 deacetylation, leading to ONFH.