Bone Research Articles

Diverse growth rates in Triassic archosaurs-insights from a small terrestrial Middle Triassic pseudosuchian.

The small pseudosuchian Benggwigwishingasuchus eremacarminis was found in Anisian (Middle Triassic) marine sediments. Neither the skeleton nor osteohistology or microanatomy shows any secondary aquatic adaptations, and a dominantly terrestrial lifestyle of this new taxon is evident. Bone tissue consists of a scaffold of parallel-fibered matrix, which is moderately vascularized by small, mainly longitudinal primary osteons. The innermost cortex is less densely vascularized and more highly organized. No parts of the cortex contain any woven bone. The cortex is regularly stratified by annual growth marks. Bone tissue and growth pattern indicate an adult individual that has had slow growth rates throughout its ontogeny. Tissue type, slow growth rate, and inferred low resting metabolic rate of Benggwigwishingasuchus are similar to that of crocodylomorphs but differ from that of Sillosuchus and Effigia, poposaurids to which Benggwigwishingasuchus is related based on phylogenetic analyses. However, according to current knowledge, growth rates in early archosaurs are more likely influenced by body size and environment than by phylogeny. Benggwigwishingasuchus is thus another example of unpredictable variability in growth rates within Triassic archosaurs.

Effect of Menstrual Cycle and Hormonal Contraception on Musculoskeletal Health and Performance: Protocol for a Prospective Cohort Design and Cross-Sectional Comparison.

Women of reproductive age experience cyclical variation in the female sex steroid hormones 17β-estradiol and progesterone during the menstrual cycle that is attenuated by some hormonal contraceptives. Estrogens perform a primary function in sexual development and reproduction but have nonreproductive effects on bone, muscle, and sinew tissues (ie, ligaments and tendons), which may influence injury risk and physical performance. The purpose of the study is to understand the effect of the menstrual cycle and hormonal contraceptive use on bone and calcium metabolism, and musculoskeletal health and performance. A total of 5 cohorts of physically active women (aged 18-40 years) will be recruited to participate: eumenorrheic, nonhormonal contraceptive users (n=20); combined oral contraceptive pill (COCP) users (n=20); hormonal implant users (n=20); hormonal intrauterine system users (n=20); and hormonal injection users (n=20). Participants must have been using the COCP and implant for at least 1 year and the intrauterine system and injection for at least 2 years. First-void urine samples and fasted blood samples will be collected for biochemical analysis of calcium and bone metabolism, hormones, and metabolic markers. Knee extensor and flexor strength will be measured using an isometric dynamometer, and lower limb tendon and stiffness, tone, and elasticity will be measured using a Myoton device. Functional movement will be assessed using a single-leg drop to assess the frontal plane projection angle and the qualitative assessment of single leg loading. Bone density and macro- and microstructure will be measured using ultrasound, dual-energy x-ray absorptiometry, and high-resolution peripheral quantitative computed tomography. Skeletal material properties will be estimated from reference point indentation, performed on the flat surface of the medial tibia diaphysis. Body composition will be assessed by dual-energy x-ray absorptiometry. The differences in outcome measures between the hormonal contraceptive groups will be analyzed in a one-way between-group analysis of covariance. Within the eumenorrheic group, the influence of the menstrual cycle on outcome measures will be assessed using a linear mixed effects model. Within the COCP group, differences across 2 time points will be analyzed using the paired-samples 2-tailed t test. The research was funded in January 2020, and data collection started in January 2022, with a projected data collection completion date of August 2024. The number of participants who have consented at the point of manuscript submission is 66. It is expected that all data analysis will be completed and results published by the end of 2024. Understanding the effects of the menstrual cycle and hormonal contraception on musculoskeletal health and performance will inform contraceptive choices for physically active women to manage injury risk. ClinicalTrials.gov NCT05587920; https://classic.clinicaltrials.gov/ct2/show/NCT05587920. DERR1-10.2196/50542.

Additive manufacturing of bioactive and biodegradable poly (lactic acid)-tricalcium phosphate scaffolds modified with zinc oxide for guided bone tissue repair.

Bioactive and biodegradable scaffolds that mimic the natural extracellular matrix of bone serve as temporary structures to guide new bone tissue growth. In this study, 3D-printed scaffolds composed of poly (lactic acid) (PLA)-tricalcium phosphate (TCP) (90-10 wt. %) were modified with 1%, 5%, and 10 wt. % of ZnO to enhance bone tissue regeneration. A commercial chain extender named Joncryl was incorporated alongside ZnO to ensure the printability of the composites. Filaments were manufactured using a twin-screw extruder and subsequently used to print 3D scaffolds via fused filament fabrication (FFF). The scaffolds exhibited a homogeneous distribution of ZnO and TCP particles, a reproducible structure with 300 µm pores, and mechanical properties suitable for bone tissue engineering, with an elastic modulus around 100 MPa. The addition of ZnO resulted in enhanced surface roughness on the scaffolds, particularly for ZnO microparticles, achieving values up to 241 nm. This rougher topography was responsible for enhancing protein adsorption on the scaffolds, with an increase of up to 85% compared to the PLA-TCP matrix. Biological analyses demonstrated that the presence of ZnO promotes mesenchymal stem cell (MSC) proliferation and differentiation into osteoblasts. Alkaline phosphatase (ALP) activity, an important indicator of early osteogenic differentiation, increased up to 29%. The PLA-TCP composite containing 5% ZnO microparticles exhibited an optimized degradation rate and enhanced bioactivity, indicating its promising potential for bone repair applications.

Graphene Oxide Nanosheets for Bone Tissue Regeneration

Graphene Oxide Nanosheets for Bone Tissue Regeneration

Requirement of Pdgfrα+ cells for calvarial bone repair.

Platelet-derived growth factor receptor α (PDGFRα) is often considered as a general marker of mesenchymal cells and fibroblasts, but also shows expression in a portion of osteoprogenitor cells. Within the skeleton, Pdgfrα+ mesenchymal cells have been identified in bone marrow and periosteum of long bones, where they play a crucial role in participating in fracture repair. A similar examination of Pdgfrα+ cells in calvarial bone healing has not been examined. Here, we utilize Pdgfrα-CreERTM;mT/mG reporter animals to examine the contribution of Pdgfrα+ mesenchymal cells to calvarial bone repair through histology and single-cell RNA sequencing (scRNA-Seq). Results showed that Pdgfrα+ mesenchymal cells are present in several cell clusters by scRNA-Seq, and by histology a dramatic increase in Pdgfrα+ cells populated the defect site at early timepoints to give rise to healed bone tissue overtime. Notably, diphtheria toxin-mediated ablation of Pdgfrα reporter+ cells resulted in significantly impaired calvarial bone healing. Our findings suggest that Pdgfrα-expressing cells within the calvarial niche play a critical role in the process of calvarial bone repair.

A maternal brain hormone that builds bone.

In lactating mothers, the high calcium (Ca2+) demand for milk production triggers significant bone loss1. Although oestrogen normally counteracts excessive bone resorption by promoting bone formation, this sex steroid drops precipitously during this postpartum period. Here we report that brain-derived cellular communication network factor 3 (CCN3) secreted from KISS1 neurons of the arcuate nucleus (ARCKISS1) fills this void and functions as a potent osteoanabolic factor to build bone in lactating females. We began by showing that our previously reported female-specific, dense bone phenotype2 originates from a humoral factor that promotes bone mass and acts on skeletal stem cells to increase their frequency and osteochondrogenic potential. This circulatory factor was then identified as CCN3, a brain-derived hormone from ARCKISS1 neurons that is able to stimulate mouse and human skeletal stem cell activity, increase bone remodelling and accelerate fracture repair in young and old mice of both sexes. The role of CCN3 in normal female physiology was revealed after detecting a burst of CCN3 expression in ARCKISS1 neurons coincident with lactation. After reducing CCN3 in ARCKISS1 neurons, lactating mothers lost bone and failed to sustain their progeny when challenged with a low-calcium diet. Our findings establish CCN3 as a potentially new therapeutic osteoanabolic hormone for both sexes and define a new maternal brain hormone for ensuring species survival in mammals.

Investigation of the Effect of Local and Systemic Preoperative Dexamethasone Application on Bone Tissue Healing in Mandibular Bone Defects.

The aim of this study was to investigate the effect of locally and systemically delivered single-dose corticosteroid injections on bone tissue. A total of 84 Wistar albino rats were divided into 2 groups as local and systemic injection groups, and 2 groups as control and experiment among themselves. Before the procedure, dexamethasone was given to the experimental group and physiological saline was given to the control group. A defect was created in the jawbone. It was sacrificed on the third, seventh, and 40th days. The mandible bones of the sacrificed rats were removed and the healing of the bone tissue was examined histopathologically. No significant difference was observed in the tissue sections of the subjects sacrificed after 40 days. However, the increase in fibroblastic connective tissue and the number of osteoblasts were less in the experimental local groups that were sacrificed after 7 days compared with the control groups (P=0.040 and 0.041). Again, it was determined that there was a statistically significant decrease in the experimental local group compared with the experimental systemic group (P=0.040 and 0.004). It can be said that single-dose corticosteroid applications cause a delay in bone healing in the early period.

Comparative study of orbital volumes according to multispiral computed tomography data

BACKGROUND: It is believed that accurate reconstruction of the correct anatomy of the orbital bony walls, restoration of symmetry and volume are necessary for a favorable functional prognosis and elimination of an aesthetic defect. The main problem when estimating orbital volume is its complex anatomy. Scientists use various methods to determine orbital volume, and in reviews comparing various methods for calculating orbital volumes, there is no data on which orbital volumetric method is the most accurate, since each of them has both advantages and disadvantages. AIM: The aim of this study is the analysis and the comparison of orbital volumes according to multispiral computed tomography data of healthy patients without bone-traumatic changes of orbital walls. MATERIALS AND METHODS: To measure the volume of orbits, 50 random patients were selected who were examined in the radiology department No. 2 of the University Clinical Hospital No. 1 of the Sechenov University from 2023 to 2024 and who underwent multispiral computed tomography of the facial skeleton for indications unrelated to orbital conditions. Computed tomography data from 25 women and 25 men of different ages (from 18 to 85 years old) were analyzed. A total of 8 groups were formed depending on gender and age: group 1 — women 18–25 years old, group 2 — men 18–25 years old, group 3 — women 26–35 years old, group 4 — men 26–35 years old, group 5 — women 36–50 years old, group 6 — men 36–50 years old, group 7 — women 51 and older, group 8 — men 51 and older. Multispiral computed tomography of the facial skeleton was performed using the Aquilion One 640 CT scanner (Japan) with 0.5 slice thickness in bone and soft tissue windows, to be able to calculate orbital volumes at the workstation, all bone contours of the orbits were marked on each axial slice, starting from the upper wall to the bottom of the orbit with a representation of the orbital volumes in ml. RESULTS: The difference in the volumes of the right and left orbits of 0.5 ml or more was detected in 5 women out of 25 cases, among men the difference was present in 12 cases out of 25; a difference in volumes of more than 1 ml was noted in 1 woman and 2 men; a difference of more than 1.5 ml was not observed in any study group. The orbital asymmetry coefficient in women ranged from 0 ml to 1.21 ml, in men — from 0.08 ml to 1.19 ml, in women, the average volume of both orbits is less than in men. It was also detected that the volume of orbits increases with age, both in men and women. CONCLUSIONS: Considering that the majority of patients had differences in orbital volumes of up to 1.0 ml, we agree with studies that indicate the possibility of using a healthy contralateral orbit as a guideline when planning reconstructive surgery. However, for planning surgical treatment, it is recommended to use manual contouring, as this allows the most accurate reproducibility of the bone boundaries of the orbit, although it requires more time than semi- and automatic segmentation. Also, the advantages of the used method for calculating the volumes of orbits in this study include reproducibility on any workstation from different manufacturers, since the method is carried out on a standard tomograph workstation and does not require any additional software.

Effects of Resistance Training, Estrogen Therapy, and Calcium Chitosan Supplement Containing Vitamin D on Bone Turnover in Ovariectomized Rats: An Experimental-Comparative Study

Background: Hormone therapy is a highly effective method for treating menopausal disorders. However, its side effects may include an increased risk of cancer, heart disease, and pulmonary embolism. Previous research has demonstrated that both exercise and nutrition separately have positive effects on menopausal symptoms. Therefore, we suggest that combining exercise and nutrition interventions may provide a synergistic effect, yielding results at least similar to those of estrogen (Est) therapy. Objectives: This study aims to compare the independent and combined effects of resistance training (RT), Est therapy, and vitamin D calcium chitosan (Vit D + Ca++ + Chit) supplementation on markers of bone turnover in ovariectomized (OVX) rats. Methods: Forty-two female Wistar rats were randomly divided into seven groups (n = 6 per group): (1) healthy-control (He-Co), (2) OVX-Vit D + Ca++ + Chit + RT, (3) OVX-saline (Sal) + Est + RT, (4) Sal + RT, (5) OVX-Vit D + Ca++ +Chit, (6) OVX-Sal + Est, and (7) OVX-Control (OVX-Co). Bone samples were extracted 48 hours after the final session. Two-way ANOVAs were used to determine differences in intervention effects between groups. The alpha level was set to 0.05. Results: Ovariectomy (OVX) decreased bone tissue expression of alkaline phosphatase (ALP) and osterix (OSX) while increasing peroxisome proliferator-activated receptor gamma (PPAR-γ) gene expression. Ovariectomy also decreased the number of osteocytes and osteoblasts while increasing the number of osteoclasts. Resistance training (RT) and Vit D + Ca++ + Chit intake increased bone tissue expression of ALP, OSX, and PPAR-γ gene expression. Additionally, RT and Vit D + Ca++ + Chit supplementation increased the number of osteocytes and osteoblasts and decreased the number of osteoclasts. Conclusions: The combined interventions had synergistic effects compared to each intervention separately on ALP, osteocyte, osteoblast, and osteoclast observations. Therefore, combining RT with Vit D + Ca++ + Chit could be a non-pharmacological approach to address bone turnover alterations caused by OVX.

Maxillary sinus lift augmentation: A randomized clinical trial with histological data comparing deproteinized bovine bone grafting vs graftless procedure with a 5-12-year follow-up.

Different protocols and procedures for sinus lift and implant placement are available, generally involving the use of grafts to increase the tissue volume and/or prevent the Schneiderian membrane from collapsing. Among xenografts, deproteinised bovine bone graft (DBBP) is frequently used in sinus lift procedures. Leaving an ungrafted space following membrane elevation has proven to have a bony regenerative potential as well. This study aimed to compare the clinical and histological features of sinus lift surgery performed with or without biomaterials. Patients with severe maxillary posterior atrophy (residual bone height 2-6 mm and residual crest thickness ≥4 mm), and in need of sinus lift surgery to allow the placement of three implants were enrolled and randomly divided into two groups. They underwent sinus lifts with DBBP (control) or with a graftless technique (test) and immediate placement of two implants (a mesial and distal one). After 6 months, a bone sample was retrieved from the area between the previously inserted fixtures, and a third, central implant was placed. The collected bone samples were analyzed morphologically and histomorphometrically. The patients were provided with prosthetic restorations after 6 months and followed up for 5-12 years. Ten patients were enrolled in the test and nine in the control group. The 6-month follow-up showed in the control group an average augmentation of 10.31 mm (±2.12), while in the test group it was 8.5 mm (±1.41) and a success rate of 96.3% in the control and 86.7% in the test group (p > 0.05). The histological analysis evidenced the presence of new bone tissue surrounded by immature osteoid matrix in the test group, and a variable number of DBBP particles surrounded by an immature woven bone matrix in the control group. The results of the present trial indicate that, with residual bone height of 2-6 mm and residual crest thickness ≥4 mm, sinus lift surgery with or without biomaterials followed by implant restoration, produces similar clinical and histological outcomes.

A Review on 3D Printing Processes in Pharmaceutical Engineering and Tissue Engineering: Applications, Trends and Challenges

AbstractAs a 3D rapid prototyping technology, 3D printing (3DP) technology has been widely applied in medical research, fabricating various medical devices or implants. With the development of biomaterials and cell‐related technologies, 3DP, especially bioprinting technology, is quietly bringing great changes and opportunities in the medical industry. Beyond surgical models, medical devices, and implants, traditional 3DP, cell‐based 3D bioprinting, and emerging 4D printing (4DP) have significantly aided in the advancement and manufacture of pharmaceuticals and biological alternatives for tissue engineering. It is envisioned that future healthcare systems, based on evolving 3DP technology and precision medicine, will deliver customized solutions that cater to the unique differences and needs of each patient. In this review work, several mainstream 3D bioprinting technologies are presented, with a focus on recent advances in 3DP for pharmaceutical engineering and important tissue engineering, including vascular and bone tissue engineering. Challenges and future prospects of 3DP for drug discovery, drug delivery systems, artificial blood vessels, vascular and bone tissue engineering scaffolds, and practical applications are also covered. Finally, the differences between 3DP and 4DP, as well as the advantages and disadvantages of different stimulus response mechanisms in 4DP and their potential applications are summarized.

Release of Exosomal PD-L1 in Bone and Soft Tissue Sarcomas and Its Relationship to Radiotherapy

(1) Background: Exosomal PD-L1 has garnered attention owing to its role in instigating systemic immune suppression. The objective of this study is to elucidate whether bone and soft tissue sarcoma cells possess the capacity to secrete functionally active exosomal PD-L1 and whether radiotherapy (RT) induces the exosomal PD-L1 release. (2) Methods: Human osteosarcoma cell line 143B and human fibrosarcoma cell line HT1080 were utilized. Exosomes were isolated from the culture medium and blood via ultracentrifugation. The expression of PD-L1 on both tumor cells and exosomes was evaluated. The inhibitory effect on PBMC was employed to assess the activity of exosomal PD-L1. Post radiotherapy, changes in PD-L1 expression were compared. (3) Results: Exosomal PD-L1 was detected in the culture medium of tumor cells but was absent in the culture medium of PD-L1 knockout cells. Exosomal PD-L1 exhibited an inhibitory effect on PBMC activation. In tumor-bearing mice, human-derived exosomal PD-L1 was detected in the bloodstream. Following radiotherapy, tumor cells upregulated PD-L1, and human-derived exosomal PD-L1 were detected in the bloodstream. (4) Conclusions: Exosomal PD-L1 emanates from bone and soft tissue sarcoma cells and is disseminated into the circulatory system. The levels of PD-L1 in tumor cells and the release of exosomal PD-L1 were augmented after irradiation with RT.

A Comprehensive Literature Review on Advancements and Challenges in 3D Bioprinting of Human Organs: Ear, Skin, and Bone.

The field of 3D bioprinting is rapidly emerging within the realm of regenerative medicine, offering significant potential in dealing with the issue of organ shortages. Despite being in its early stages, it has the potential to replicate tissue structures accurately, providing new potential solutions for reconstructive surgery. This review explores the diverse applications of 3D bioprinting in regenerative medicine, pharmaceuticals, and the food industry, specifically focusing on ear, skin, and bone tissues due to their unique challenges and implications in the field. Significant progress has been made in cartilage and bone scaffold fabrication in ear reconstruction, yet challenges in functional maturation persist. Recent advancements highlight the potential for patient-specific ear substitutes, emphasizing the need for extensive clinical trials. In skin regeneration, 3D bioprinting addresses limitations in existing models, offering opportunities for improved wound healing and realistic skin models. While challenges exist, progress in biomaterials and in-situ bioprinting holds promise. In bone regeneration, 3D bioprinting presents personalized solutions for defects, but scaffold design refinement and addressing regulatory and ethical considerations are crucial. The transformative potential of 3D bioprinting in the field of medicine holds the promise of redefining therapeutic approaches and delivering personalized treatments and functional tissues. Interdisciplinary collaboration is essential for fully realizing the capabilities of 3D bioprinting. This review provides a detailed analysis of current methodologies, challenges, and prospects in 3D bioprinting for ear, skin, and bone tissue regeneration.

Preparation and Structure–Property Relationship Study of Piezoelectric–Conductive Composite Polymer Nanofiber Materials for Bone Tissue Engineering

This study aimed to develop Janus-, cross-network-, and coaxial-structured piezoelectric–conductive polymer nanofibers through electrospinning to mimic the piezoelectricity of bone and facilitate the conduction of electrical signals in bone tissue repair. These nanofibers were constructed using the piezoelectric polymer polyvinylidene fluoride, and the conductive fillers reduced graphene oxide and polypyrrole. The influence of structural features on the electroactivity of the fibers was also explored. The morphology and components of the various structural samples were characterized using SEM, TEM, and FTIR. The electroactivity of the materials was assessed with a quasi-static d33 meter and the four-probe method. The results revealed that the piezoelectric–conductive phases were successfully integrated. The Janus-structured nanofibers demonstrated the best electroactivity, with a piezoelectric constant d33 of 24.5 pC/N and conductivity of 6.78 × 10−2 S/m. The tensile tests and MIP measurements showed that all samples had porosity levels exceeding 70%. The tensile strength of the Janus and cross-network structures exceeded that of the periosteum (3–4 MPa), with average pore sizes of 1194.36 and 2264.46 nm, respectively. These properties indicated good mechanical performance, allowing material support while preventing fibroblast invasion. The CCK-8 and ALP tests indicated that the Janus-structured samples were biocompatible and significantly promoted the proliferation of MC3T3-E1 cells.

Ti3C2Tx MXene-Decorated 3D-Printed Ceramic Scaffolds for Enhancing Osteogenesis by Spatiotemporally Orchestrating Inflammatory and Bone Repair Responses.

Inflammatory responses play a central role in coordinating biomaterial-mediated tissue regeneration. However, precise modulation of dynamic variations in microenvironmental inflammation post-implantation remains challenging. In this study, the traditional β-tricalcium phosphate-based scaffold is remodeled via ultrathin MXene-Ti3C2 decoration and Zn2+/Sr2+ ion-substitution, endowing the scaffold with excellent reactive oxygen species-scavenging ability, near-infrared responsivity, and enhanced mechanical properties. The induction of mild hyperthermia around the implant via periodic near-infrared irradiation facilitates spatiotemporal regulation of inflammatory cytokines secreted by a spectrum of macrophage phenotypes. The process initially amplifies the pro-inflammatory response, then accelerates M1-to-M2 macrophage polarization transition, yielding a satisfactory pattern of osteo-immunomodulation during the natural bone healing process. Later, sustained release of Zn2+/Sr2+ ions with gradual degradation of the 3D scaffold maintains the favorable reparative M2-dominated immunological microenvironment that supports new bone mineralization. Precise temporal immunoregulation of the bone healing process by the intelligent 3D scaffold enhances bone regeneration in a rat cranial defect model. This strategy paves the way for the application of β-tricalcium phosphate-based materials to guide the dynamic inflammatory and bone tissue responses toward a favorable outcome, making clinical treatment more predictable and durable. The findings also demonstrate that near-infrared irradiation-derived mild hyperthermia is a promising method of immunomodulation.

Development of surface‐treated poly(lactic acid)/zinc oxide biocomposites for 3D printing in bone tissue engineering

AbstractThe increase in bone fractures has been driving the development of materials for bone repair with better mechanical and biological properties. This work reports the development of poly (lactic acid) (PLA)‐zinc oxide (ZnO) biocomposites for 3D printing of scaffolds to be applied in bone tissue engineering. The ZnO surface was functionalized with maleic anhydride (ZnOMA) by applying radio frequency plasma treatment as an alternative to control the catalytic effects of ZnO on the degradation of the PLA during the molten state processing. PLA and ZnOMA powders were processed using a heated internal mixer and the resulted biocomposites were used to manufacture scaffolds by 3D printing. The scaffolds were characterized by their rheological, thermal, microstructural, mechanical, and biological properties. Compositions containing ZnOMA presented higher viscosities, evidencing the control of degradation by surface functionalization, and achieved an elastic modulus near 1 GPa, suitable for bone applications, unlike the untreated samples. In relation to cell functions, PLA‐ZnOMA scaffolds exhibited cell viabilities at 160%, compared to 50% for untreated samples and stimulated mesenchymal stem cells toward osteoblast. Therefore, ZnO's negative thermal degradation effect on PLA was successfully overcome using plasma functionalization, enabling the 3D printing of bioactive scaffolds with great potential for application in tissue engineering.

Percutaneous unilateral vertebro-stentoplasty for painful osteoporotic compression fracture of lumbar vertebra

Osteoporosis is one of the common diseases in the elderly population which can cause compression fracture of the vertebral body due to loss of microarchitecture, loss of density, and deterioration of bone tissue leading to chronic pain, kyphotic deformity of the vertebra, and neurological complications. We report the case of a 68-year-old female, who presented to us with severe midback region pain for one year, which was increased over two months along with numbness in the right leg and difficulty in walking. The radiological investigation and magnetic resonance imaging spine revealed chronic compression fracture with the reduction in height of the L1 vertebra, which is seen with anterior wedging. The patient underwent vertebro-stentoplasty (VS) with bone cement, polymethyl-methacrylate. The patient was discharged well on third day of surgery. The VS for compression fracture of the lumbar vertebra demonstrated better results with improvement in pain and radiological finding in our patient.

Design of Alginate/Gelatin Hydrogels for Biomedical Applications: Fine-Tuning Osteogenesis in Dental Pulp Stem Cells While Preserving Other Cell Behaviors

Alginate/gelatin (Alg-Gel) hydrogels have been used experimentally, associated with mesenchymal stromal/stem cells (MSCs), to guide bone tissue formation. One of the main challenges for clinical application is optimizing Alg-Gel stiffness to guide osteogenesis. In this study, we investigated how Alg-Gel stiffness could modulate the dental pulp stem cell (DPSC) attachment, morphology, proliferation, and osteogenic differentiation, identifying the optimal conditions to uncouple osteogenesis from the other cell behaviors. An array of Alg-Gel hydrogels was prepared by casting different percentages of alginate and gelatin cross-linked with 2% CaCl2. We have selected two hydrogels: one with a stiffness of 11 ± 1 kPa, referred to as “low-stiffness hydrogel”, formed by 2% alginate and 8% gelatin, and the other with a stiffness of 55 ± 3 kPa, referred to as “high-stiffness hydrogel”, formed by 8% alginate and 12% gelatin. Hydrogel analyses showed that the average swelling rates were 20 ± 3% for the low-stiffness hydrogels and 35 ± 2% for the high-stiffness hydrogels. The degradation percentage was 47 ± 5% and 18 ± 2% for the low- and high-stiffness hydrogels, respectively. Both hydrogel types showed homogeneous surface shape and protein (Alg-Gel) interaction with CaCl2 as assessed by physicochemical characterization. Cell culture showed good adhesion of the DPSCs to the hydrogels and proliferation. Furthermore, better osteogenic activity, determined by ALP activity and ARS staining, was obtained with high-stiffness hydrogels (8% alginate and 12% gelatin). In summary, this study confirms the possibility of characterizing and optimizing the stiffness of Alg-Gel gel to guide osteogenesis in vitro without altering the other cellular properties of DPSCs.

New mechanistic understanding of osteoclast differentiation and bone resorption mediated by P2X7 receptors and PI3K-Akt-GSK3β signaling.

Osteoporosis is a global health issue characterized by decreased bone mass and microstructural degradation, leading to an increased risk of fractures. This study aims to explore the molecular mechanism by which P2X7 receptors influence osteoclast formation and bone resorption through the PI3K-Akt-GSK3β signaling pathway. An osteoporosis mouse model was generated through ovariectomy (OVX) in normal C57BL/6 and P2X7f/f; LysM-cre mice. Osteoclasts were isolated for transcriptomic analysis, and differentially expressed genes were selected for functional enrichment analysis. Metabolite analysis was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS), and multivariate statistical analysis and pattern recognition were used to identify differential lipid metabolism markers and their distribution. Bioinformatics analyses were conducted using the Encyclopedia of Genes and Genomes database and the MetaboAnalyst database to assess potential biomarkers and create a metabolic pathway map. Osteoclast precursor cells were used for in vitro cell experiments, evaluating cell viability and proliferation using the Cell Counting Kit 8 (CCK-8) assay. Osteoclast precursor cells were induced to differentiate into osteoclasts using macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor kappa-beta ligand (RANKL), and tartrate-resistant acid phosphatase (TRAP) staining was performed to compare differentiation morphology, size, and quantity between different groups. Western blot analysis was used to assess the expression of differentiation markers, fusion gene markers, and bone resorption ability markers in osteoclasts. Immunofluorescence staining was employed to examine the spatial distribution and quantity of osteoclast cell skeletons, P2X7 protein, and cell nuclei, while pit assay was used to evaluate osteoclast bone resorption ability. Finally, in vivo animal experiments, including micro computed tomography (micro-CT), hematoxylin and eosin (HE) staining, TRAP staining, and immunohistochemistry, were conducted to observe bone tissue morphology, osteoclast differentiation, and the phosphorylation level of the PI3K-Akt-GSK3β signaling pathway. Transcriptomic and metabolomic data collectively reveal that the P2X7 receptor can impact the pathogenesis of osteoporosis through the PI3K-Akt-GSK3β signaling pathway. Subsequent in vitro experiments showed that cells in the Sh-P2X7 + Recilisib group exhibited increased proliferative activity (1.15 versus 0.59), higher absorbance levels (0.68 versus 0.34), and a significant increase in resorption pit area (13.94 versus 3.50). Expression levels of osteoclast differentiation-related proteins MMP-9, CK, and NFATc1 were markedly elevated (MMP-9: 1.72 versus 0.96; CK: 2.54 versus 0.95; NFATc1: 3.05 versus 0.95), along with increased fluorescent intensity of F-actin rings. In contrast, the OE-P2X7 + LY294002 group showed decreased proliferative activity (0.64 versus 1.29), reduced absorbance (0.34 versus 0.82), and a significant decrease in resorption pit area (5.01 versus 14.96), accompanied by weakened expression of MMP-9, CK, and NFATc1 (MMP-9: 1.14 versus 1.79; CK: 1.26 versus 2.75; NFATc1: 1.17 versus 2.90) and decreased F-actin fluorescent intensity. Furthermore, in vivo animal experiments demonstrated that compared with the wild type (WT) + Sham group, mice in the WT + OVX group exhibited significantly increased levels of CTX and NTX in serum (CTX: 587.17 versus 129.33; NTX: 386.00 versus 98.83), a notable decrease in calcium deposition (19.67 versus 53.83), significant reduction in bone density, increased trabecular separation, and lowered bone mineral density (BMD). When compared with the KO + OVX group, mice in the KO + OVX + recilisib group showed a substantial increase in CTX and NTX levels in serum (CTX: 503.50 versus 209.83; NTX: 339.83 versus 127.00), further reduction in calcium deposition (29.67 versus 45.33), as well as decreased bone density, increased trabecular separation, and reduced BMD. P2X7 receptors positively regulate osteoclast formation and bone resorption by activating the PI3K-Akt-GSK3β signaling pathway.

Dynamic spinal orthoses self-reported effects in patients with back pain due to vertebral fragility fractures: A multi-center prospective cohort study.

Vertebral fragility fractures (VFFs) commonly result from low bone mass and microarchitecture deterioration of bone tissue. spinal orthoses are common non-pharmacological options for managing vertebral fracture pain. However, the effects of spinal orthoses on pain, physical functioning, and quality of life (QoL) are still debated. This survey aimed to investigate the patients-reported outcomes of a dynamic spinal orthosis prescribed in the routine clinical practice of VFFs management. This multi-center national-wide prospective cohort study assessed older patients (aged > 60years) diagnosed with acute VFFs and prescribed with a dynamic spinal orthosis (Spinfast®). A survey questionnaire was realized and included sections on patient characterization, osteoporosis characterization, spinal orthosis, clinical outcomes, pain medications, and osteoporosis medications. The questionnaire was administered at baseline and after three months. A total of 68 patients completed the questionnaire at three months. Most patients had one or two VFFs and were treated with pain medications and osteoporosis medications. Compliance and tolerability of the spinal orthosis were assessed, and clinical outcomes such as pain intensity, physical functioning, and QoL were measured. The results showed no significant differences in outcomes between age subgroups. Italian physical medicine and rehabilitation physicians were commonly involved in the management of VFFs patients. Sixty-six patients completed the questionnaire. The results showed that pain intensity, physical functioning and QoL improved after three months of spinal orthosis wearing (p< 0.0001). The correct management of VFFs is mandatory to improve pain and reduce disability, and our findings suggested a positive role of dynamic spinal orthosis to improve the comprehensive management of VFFs patients. However, high-quality research trials are warranted to provide clear recommendations for the correct clinical management of VFF.