Matrix Mineralization Research Articles

Innovative 3D-Printed Titanium Specimens Favor a Modulation of Inflammation in Dental Pulp Stem Cells During Liposome-Triggered Mineralization.

developing customized titanium specimens, with innovative surfaces, is a suitable strategy to overcome implant failure. Additionally, a faster and efficient osteogenic commitment assists tissue regeneration. To investigate the interplay between inflammation and differentiation upon implantation, Dental Pulp Stem Cells (DPSCs) were cultured on 3D-printed titanium owning an internal open cell form, administering osteogenic factors by a liposomal formulation (LipoMix) compared to traditional delivery of differentiation medium (DM). osteogenic differentiation was evaluated by western blot, by measuring β1 integrin expression, and by and real-time RT-PCR, by measuring SP7 and Collagen I gene expression; while.angiogenesis was characterized by measuring VEGF secretion levels. Matrix mineralization was assessed by means of Alizarin Red Staining, cell adhesion and inflammation responses through western blot, enzymatic and ELISA assays evaluating Nrf2 expression, catalase activity and Prostaglandin E2 secretion, respectively. LipoMix enhances cell proliferation and adhesion, as revealed by increased integrin β1 expression. Mineralized matrix deposition, SP7 gene expression, Collagen I release and Alkaline Phosphatase activity appear increased in LipoMix condition. Additionally, the redox-sensitive transcription factor Nrf2 is overexpressed at the earliest experimental times, triggering the catalase activity. data reported confirm that internal topography and post-production treatments on titanium surfaces dynamically and positively condition the DPSC progress towards the osteogenic phenotype, moreover, the combination with LipoMix fastens the positive modulation of inflammation under osteogenic conditions. Therefore, the development of customized surfaces along with the administration of differentiating factors enclosed in a liposomal delivery system, could represent a promising and innovative tool in regenerative dentistry.

Potential of Cranberry to Stimulate Osteogenesis: An In Vitro Study

This study investigated the potential of Cranberry extract to stimulate osteogenesis in vitro. The total phenolic and monomeric anthocyanin contents in the Cranberry were determined. Liquid chromatography coupled with mass spectrometry was used to identify the Cranberry’s constituents. To assess the Cranberry’s cytotoxicity, a thiazolyl blue tetrazolium bromide assay was employed. Concerning the osteogenesis potential of Cranberry, alkaline phosphatase (ALP) activity, bone morphogenetic protein 2 (BMP-2) expression, and extracellular matrix mineralization were evaluated. The total phenolic content was 522.72 ± 9.80 mg GAE g-1 ES and 364.95 ± 12.49 mg GAE/g detected by the Fast Blue BB and Folin–Ciocalteu method, respectively. For monomeric anthocyanin, the content was 460 ± 30 mg ECG g-1 ES. Moreover, Cranberry concentrations ranged from 62.5 to 500 mg/mL and were found to be biocompatible with osteoblasts and mesenchymal stromal cells. Regarding osteogenesis, 20 mg/mL of Cranberry promoted 2-fold more ALP activity and almost 1.5-fold more BMP-2 than compared to the positive control group. Additionally, 200 mg/mL of Cranberry stimulated a 1.7-fold increase in extracellular matrix mineralization compared to the positive control group. In conclusion, Cranberry displayed potential in stimulating early and late markers of osteogenesis. Its ability to promote osteogenesis and its biocompatibility at higher concentrations hold promise for future application into biomaterials for bone regeneration.

Bioleaching of Industrial Metallic Steel Waste by Mixed Cultures of Thermoacidophilic Archaea

Different mixed cultures of extremely thermoacidophilic microorganisms were used for bioleaching of metalliferous industrial dust waste derived from the basic oxygen furnace (BOF) steelmaking process. Such mixed cultures can extract various metals from multi-metallic BOF-dust waste, improving the metal dissolution and bioleaching performance in frames of metal recycling processes to assist circular economies and waste management. The results of the investigation showed that mixed cultures of thermoacidophilic archaea of the order Sulfolobales (Acidianus spp., Sulfolobus spp., and Metallosphaera sedula) during their growth in laboratory glass bioreactors provided a superior bioleaching system to Acidianus manzaensis alone. Depending on the composition of mixed thermoacidophilic cultures, extraction of various metals from BOF-dust could be achieved. Among the three different types of mixed cultures tested, the mixed culture system of A. manzaensis, A. brierleyi, and S. acidocaldarius was most effective for extraction of major elements (Fe, Ca, Zn, Mn, and Al). The mixed culture of A. manzaensis, A. brierleyi, and M. sedula showed high performance for bioleaching of most of the minor elements (Cu, Ni, Pb, Co, Mo, and Sr). The efficient ability of mixed cultures to colonise the mineral matrix of the metal waste product was observed via scanning electron microscopy, while their metal extraction capacities were analysed by inductively coupled plasma mass spectrometry. These investigations will promote the further design of microbial consortia in order to break down the solid matrix and efficiently extract metals from metalliferous waste materials.

Mitigation of Fluoride Contamination in Drinking Water Supply Sources by Adsorption Using Bone Char: Effects of Mineral and Organic Matrix

This study focused on fluoride (F−) contamination of water sources in Bahimi village, Cameroon. After the first investigation, results revealed that all water samples collected had elevated concentrations of fluoride ions (2.3 ± 0.1) mg/L to (4.5 ± 0.2) mg/L above the WHO guidelines (less than 1.5 mg/L). To mitigate the F− levels, the use of bone char (BC) as an adsorbent material was proposed and its performance was tested. BC was prepared from bovine bones at different calcination temperatures (350 °C, 450 °C, 550 °C and 650 °C) and residence times (1 h and 2 h). The prepared materials were characterized in detail by SEM/EDS, BET, FTIR, and XRD. The BET findings indicated that the surface area of BC samples decreased with increasing calcination temperature and residence time. At a lower heating temperature and holding time (350 °C, 1 h), the prepared BC exhibited a higher specific surface area (112.3 ± 0.3) m2/g and adsorption capacity for F− in the sampled water. Also, the batch adsorption experiments showed that the optimized adsorbent dose of 8 g/L facilitates the reduction in the F− level of the sampled water below the acceptable limit level (1.5 mg/L) within 5 min of treatment. The presence of Ca2+ and Mg2+ in natural water has a positive effect on the removal of F− in BC resulting in a high adsorption performance range of (72.5 ± 1.4)% to (80.3 ± 0.6)%. It was found that the adsorption of Ca2+ on the BC surface occurs via cation exchange with Na+. However, an increase in dissolved organic carbon (DOC) in the treated water limited the application of BC. Overall, the study presented a cost-effective adsorbent for the removal of this recalcitrant ion in the water source.

TMEM175 Plays a Crucial Role in Osteoblast Differentiation by Regulating Lysosomal Function and Autophagy.

Bone provides structural support, enables movement, protects internal organs, regulates calcium and phosphorus levels, and contains bone marrow essential for hematopoiesis. Osteoblasts are specialized cells responsible for bone formation through the secretion of extracellular matrix components. Transmembrane protein 175 (TMEM175), which functions as an endosomal/lysosomal K+ channel and a lysosomal H+ channel, regulates lysosomal function and autophagy. Despite the recognized importance of lysosomes and autophagy in osteoblast differentiation, the specific role of TMEM175 in osteoblast differentiation has not been revealed. In this study, we investigated whether TMEM175 is associated with human bone mineral density (BMD) and fracture, and examined the role of TMEM175 in osteoblast differentiation. In analyses of single nucleotide polymorphisms (SNPs) of pore ion channel genes using the mouse2human database, a significant correlation between TMEM175 SNPs and human BMD and fracture was identified. TMEM175 expression levels were found to increase during osteoblast differentiation from bone chip-derived mesenchymal stem cells (BMSCs). Knockdown of TMEM175 in BMSCs suppressed osteoblast differentiation, as evidenced by decreased matrix mineralization and lower expression levels of osteoblast marker genes. Further analysis indicated that TMEM175 deficiency leads to lysosomal dysfunction and partially impairs autophagic clearance during osteoblast differentiation. Moreover, the TMEM175 inhibitor 4-aminopyridine (4-AP) decreased osteoblast differentiation of BMSCs. Taken together, this study reveals that TMEM175 plays an important role for osteoblast differentiation by regulating lysosomal function and autophagic clearance.

Tauroursodeoxycholic acid combined with selenium accelerates bone regeneration in ovariectomized rats.

More recently, increased studies have revealed that antioxidants can cure osteoporosis by inhibiting oxidative stress. Tauroursodeoxycholic acid (TUDCA) and Selenium (Se) have been confirmed to possess potent anti-oxidative effects and accelerate bone regeneration. In addition, very little is currently known about the effects of a combination with Se and TUDCA on bone defects in osteoporotic states. We, therefore, aimed to assess the protective effect of combination with Se and TUDCA on bone regeneration and investigate the effect and underlying mechanisms. When MC3T3-E1 was cultured in the presence of H2H2, Se, TUDCA and Se/TUDCA therapy could increase the matrix mineralization and promote expression of anti-oxidative stress markers in MC3T3-E1, while reducing intracellular reactive oxygen species (ROS) and mitochondrial ROS levels. Meanwhile, silent information regulator type 1 (SIRT1) was upregulated in response to Se, TUDCA and Se/TUDCA exposures in H2H2 treated-MC3T3-E1. In the OVX rat model, Se, TUDCA and Se/TUDCA showed a clear positive effect against impaired bone repair in osteoporosis. The results above demonstrate that Se/TUDCA exhibits superior efficacy in both cellular and animal experiments, as compared to Se and TUDCA. In conclusion, combination with Se and TUDCA stimulates bone regeneration and is a promising candidate for promoting bone repair in osteoporosis.

Extracorporeal Magnetotransduction Therapy as a New Form of Electromagnetic Wave Therapy: From Gene Upregulation to Accelerated Matrix Mineralization in Bone Healing.

Electromagnetic field therapy is gaining attention for its potential in treating bone disorders, with Extracorporeal Magnetotransduction Therapy (EMTT) emerging as an innovative approach. EMTT offers a higher oscillation frequency and magnetic field strength compared to traditional Pulsed Electromagnetic Field (PEMF) therapy, showing promise in enhancing fracture healing and non-union recovery. However, the mechanisms underlying these effects remain unclear. This study demonstrates that EMTT significantly enhances osteoblast bone formation at multiple levels, from gene expression to extracellular matrix mineralization. Key osteoblastogenesis regulators, including SP7 and RUNX2, and bone-related genes such as COL1A1, ALPL, and BGLAP, were upregulated, with expression levels surpassing those of the control group by over sevenfold (p < 0.001). Enhanced collagen synthesis and mineralization were confirmed by von Kossa and Alizarin Red staining, indicating increased calcium and phosphate deposition. Additionally, calcium imaging revealed heightened calcium influx, suggesting a cellular mechanism for EMTT's osteogenic effects. Importantly, EMTT did not compromise cell viability, as confirmed by live/dead staining and WST-1 assays. This study is the first to show that EMTT can enhance all phases of osteoblastogenesis and improve the production of critical mineralization components, offering potential clinical applications in accelerating fracture healing, treating osteonecrosis, and enhancing implant osseointegration.

Europium-Containing Nanospheres for Treating Ovariectomy-Induced Osteoporosis: Targeted Bone Remodeling and Macrophage Polarization Modulation.

Osteoporosis, characterized by reduced bone mass and structural deterioration, poses a significant healthcare challenge. Traditional treatments, while effective in reducing fracture risks, are often limited by side effects. This study introduces a novel nanocomplex, europium (Eu) ions-doped superparamagnetic iron oxide (SPIO) nanocrystals encapsulated in poly(lactic-co-glycolic acid) (PLGA) nanospheres, abbreviated as SPIO:Eu@PLGA nanospheres, as a potential therapeutic agent for osteoporosis by modulating macrophage polarization, enhancing osteoblast differentiation and inhibiting osteoclastogenesis. SPIO and SPIO:Eu nanocrystals were synthesized through pyrolysis and encapsulated in PLGA using an emulsification method. To evaluate the impact of SPIO:Eu@PLGA nanospheres on macrophage reprogramming and reactive oxygen species (ROS) production, flow cytometry analysis was conducted. Furthermore, an ovariectomized (OVX) rat model was employed to assess the therapeutic efficacy of SPIO:Eu@PLGA nanospheres in preventing the deterioration of osteoporosis. In vitro, SPIO:Eu@PLGA nanospheres significantly attenuated M1 macrophage activation induced by lipopolysaccharides, promoting a shift towards the M2 phenotype. This action is linked to the modulation of ROS and the NF-κB pathway. Unlike free Eu ions, which do not achieve similar results when not incorporated into the SPIO nanocrystals. SPIO:Eu@PLGA nanospheres enhanced osteoblast differentiation and matrix mineralization while inhibiting RANKL-induced osteoclastogenesis. In vivo studies demonstrated that SPIO:Eu@PLGA nanospheres effectively targeted trabecular bone surfaces in OVX rats under magnetic guidance, preserving their structure and repairing trabecular bone loss by modulating macrophage polarization, thus restoring bone remodeling homeostasis. The study underscores the critical role of Eu doping in boosting the anti-osteoporotic effects of SPIO:Eu@PLGA nanospheres, evident at both cellular and tissue levels in vitro and in vivo. The inclusion of Eu into SPIO matrix suggests a novel approach for developing more effective osteoporosis treatments, particularly for conditions induced by OVX. This research provides essential insights into SPIO:Eu@PLGA nanospheres as an innovative osteoporosis treatment, addressing the limitations of conventional therapies through targeted delivery and macrophage polarization modulation.

Synthesis and Characterization of Shungite Modified Poly-N-Ninylpyrrolidone-Agarose Composites for Medical Application.

A systematic investigation was conducted to synthesize hybrid composite materials that use synthetic poly-N-vinylpyrrolidone and natural (agar-agar) macromolecules with plasticizers (PEG-400) and mineral filler shungite by means of electron irradiation. The XRD and SEM data showed that the structure of the resulting hybrid composites is an interpenetrating network with distributed particles of mineral component. It has been established that the mechanical properties of hybrid composites are determined mainly by the structural organization of the interpenetrating polymer network formed under electron irradiation of the initial synthetic and natural polymer mixture in the presence of plasticizers, as well as by the conditions for intercalation of polymer segments into the mineral matrix and vice versa. It has been revealed that the degree of swelling of hybrid composites strongly depends on the concentration of a low-molecular plasticizer in the polymeric interpenetrating network, which easily impregnates into the matrix of shungite. Successfully obtained [PVP-AA-PEG] hydrogels with shungite can be applied in regenerative medicine as wound healing dressings.

Changes in Kerogen and Mineral Matrix Characteristics of Rocks of Bazhenov Deposits during Laboratory Modelling of Hydrothermal Processes

Changes in Kerogen and Mineral Matrix Characteristics of Rocks of Bazhenov Deposits during Laboratory Modelling of Hydrothermal Processes

Thermal insulation and fire protection plaster for FRP systems incorporating aerogel nanoparticles and phyllosilicates

Fiber Reinforced Polymers (FRP) Systems are the most advanced systems in structural repair and strengthening field for their minimal time of application, limited space needed, and high durability. However, FRP systems still have a major drawback that limits their utilization in many projects, namely low fire-resistance. A novel material that was introduced lately with a substantial thermal performance is Aerogel, which has been widely utilized in other fields. This study attempted to develop fire-protective plaster incorporating nano silica-aerogel particles and phyllosilicates. During the experimental process, different surfactants were assessed as wetting agents, and their impact on both cement and mineral matrices. Finally, the selected plaster was evaluated under fire conditions. The results reveal that aerogel incorporation in mineral (gypsum) matrix was successfully achieved using various types of surfactants. The mechanical and thermal performance of the developed plasters were promising, with a fire-rating performance reaching 82 minutes for FRP system.

Influence of different growth conditions on the composition and acidogenicity of saliva-derived microcosm biofilm and their effects on enamel demineralization

This study compared the influence of growth conditions on the composition and acidogenicity of saliva-derived microcosm biofilms and enamel demineralization. Biofilms grown in sucrose-supplemented modified McBain medium, containing 25/50 mmol/L PIPES (buffer), under anaerobiosis/microaerophilia, for 3 and 7 days were evaluated for their acidogenicity, microbial composition, matrix, and enamel mineral content. The viability of total lactobacilli was higher in the group containing 25 mmol/L PIPES grown under anaerobiosis, which also showed lower pH values. The viability of total streptococci and total microorganisms was significantly higher at 7 days in the groups with 50 mmol/L PIPES than at 3 days, regardless of the incubation atmosphere. No significant differences were observed in lactic acid, calcium, superficial hardness loss, or lesion depth. In conclusion, the incubation atmosphere, buffer content in the growth media, and duration of biofilm formation displayed species-varied influence on microcosm biofilms, without causing significant changes in acid metabolism or enamel demineralization.

Sequential release of vancomycin and BMP-2 from chitosan/nano-hydroxyapatite thermosensitive hydrogel for the treatment of chronic osteomyelitis

In this study, we developed scaffolds materials with microspheres to form a double sustained release system.Chitosan/nano-hydroxyapatite (CS-HA) was used as a drug carrier to construct a sustained-release system for Bone morphogenetic protein-2(BMP-2) and Vancomycin (VAN). Furthermore, VAN and BMP-2 loaded microspheres (Ms) were prepared by the emulsion ultrasonic method.The resultant composites were characterized by Scanning electron microscope (SEM), compressive strength, porosity, and biodegradation. The characterization results showed uniform porous and rough surface, enhanced thermal stability, and highest compressive strength ((1.912 ± 0.012) Kpa, the surface of the two microspheres was slightly folded and showed a regular spherical shape.The loading rate of BMP-2 was (59.611 × 10-4 ± 0.023 × 10-4)% and the encapsulation rate was (6.022 ± 0.005)%. The release rate of vancomycin and BMP-2 was 57.194% and 12.968% respectively. Osteogenic differentiation of Bone marrow mesenchymal stem cells (BMSCs) was confirmed by alkaline phosphatase quantification. The deposition of late osteogenic markers (calcium phosphates) detected by Alizarin red, which indicated extracellular matrix mineralization. The results showed that BMP-2/VAN in CS-HA hydrogel successfully achieved the sequential release of the double drugs, which could benefit bone regeneration.

Combined Effects of Cyclic Hypoxic and Mechanical Stimuli on Human Bone Marrow Mesenchymal Stem Cell Differentiation: A New Approach to the Treatment of Bone Loss.

Background: The prevention and treatment of bone loss and osteoporotic fractures is a public health challenge. Combined with normobaric hypoxia, whole-body vibration has a high clinic potential in bone health and body composition. The effect of this therapy may be mediated by its action on bone marrow mesenchymal stem cells (MSCs). Objectives: Evaluate the effects of cyclic low-vibration stimuli and/or hypoxia on bone marrow-derived human MSC differentiation. Methods: MSCs were exposed four days per week, two hours/day, to hypoxia (3% O2) and/or vibration before they were induced to differentiate or during differentiation into osteoblasts or adipocytes. Gene and protein expression of osteoblastic, adipogenic, and cytoskeletal markers were studied, as well as extracellular matrix mineralization and lipid accumulation. Results: early osteoblastic markers increased in undifferentiated MSCs, pretreated in hypoxia and vibration. This pretreatment also increased mRNA levels of osteoblastic genes and beta-catenin protein in the early stages of differentiation into osteoblasts without increasing mineralization. When MSCs were exposed to vibration under hypoxia or normoxia during osteoblastic differentiation, mineralization increased with respect to cultures without vibrational stimuli. In MSCs differentiated into adipocytes, both in those pretreated as well as exposed to different conditions during differentiation, lipid formation decreased. Changes in adipogenic gene expression and increased beta-catenin protein were observed in cultures treated during differentiation. Conclusions: Exposure to cyclic hypoxia in combination with low-intensity vibratory stimuli had positive effects on osteoblastic differentiation and negative ones on adipogenesis of bone marrow-derived MSCs. These results suggest that in elderly or frail people with difficulty performing physical activity, exposure to normobaric cyclic hypoxia and low-density vibratory stimuli could improve bone metabolism and health.

Evaluation of mechanical behaviour of vegetal FRCM composites through the DIC technique: Effects of textile pre-impregnation and short flax fibres

FRCM composites are intended for the reinforcement of structural elements such as concrete and masonry. In the current environmental context, vegetal FRCM made from plant textiles such as flax, hemp or jute represent a promising alternative to synthetic FRCM typically made from carbon or glass textiles. However, the mechanical behaviour and damage mechanism of these vegetal composites are intricate and require further investigation to improve their appeal for real-world applications. This paper investigates the global and local tensile behaviour of vegetal FRCM composites using Digital Image Correlation (DIC). Three different types of textiles have been selected for Flax-FRCM (flax textile), Jute-FRCM (jute textile) and Carbon-FRCM (carbon textile) composites, which serve as references. The objective is to evaluate the influence of the physical and mechanical properties of the textiles, the addition of short flax fibres to the mineral matrix, the pre-impregnation of the plant textiles in the mineral matrix and the reinforcement ratio on the mechanical performance of the composites. The results showed that these parameters significantly affect the FRCM mechanical response in terms of the stress-strain curves, tensile properties, crack spacing, crack widths and their evolution during loading, failure mode and the exploitation rate of the textile in the composite (efficiency factor, crucial for structural applications). Furthermore, combining textile pre-impregnation with the addition of short flax fibres showed the best tensile performance for vegetal FRCM composites, notably through a significant reduction in crack widths and textile failures in the centre of the specimen.

Temperature induced fast-setting of cement based mineral-impregnated carbon-fiber reinforcements for durable and lightweight construction with textile-reinforced concrete

Developing durable and sustainable mineral-impregnated carbon-fiber (MCF) reinforcement system is today an effective measure to solve common service issues of conventional steel or FRP reinforcement in building sector. This study introduces a novel methodology for the design and realization of fast-setting cement based MCF reinforcements via targeted thermal activation. The process involves impregnating continuous yarns with a micro-sized particle cement suspension utilizing custom-built manufacturing equipment. Subsequently, the impregnated yarns undergo controlled heating at moderate temperatures to accelerate the cure process and strength development. Flexural and tensile performance of the MCFs exhibits progressive improvements with longer curing durations (from 2 to 20 h) and higher temperatures (from 40 °C to 60 °C). Enhanced mechanical properties are attributed to advanced hydration reactions and microstructural densification, as proven by thermogravimetric analysis (TGA), mercury intrusion porosimetry (MIP), scanning electron microscopy, isothermal calorimetry and micro-computed tomography (μCT). When heating at 60 °C for 20 h, as-produced MCFs demonstrate optimal tensile strength of 2747 MPa and flexural strength of 482 MPa, with exceptional bond with concrete substrate, comparable to conventional FRPs. The proposed post-treatment shows promising potential for significantly enhancing the flexibility of mineral matrix composites, making them suitable for a wide range of industrial and field applications.

Laponite modified methacryloyl gelatin hydrogel with controlled release of vascular endothelial growth factor a for bone regeneration

Reconstruction of bone defects has long been a major clinical challenge. Limited by the various shortcomings of conventional treatment like autologous bone grafting and inorganic substitutes, the development of novel bone repairing strategies is on top priority. Injectable biomimetic hydrogels that deliver stem cells and growth factors in a minimally invasive manner can effectively promote bone regeneration and thus represent a promising alternative. Therefore, in this study, we designed and constructed an injectable nanocomposite hydrogel co-loaded with Laponite (Lap) and vascular endothelial growth factor (VEGF) through a simplified and convenient scheme of physical co-mixing (G@Lap/VEGF). The introduced Lap not only optimized the injectability of GelMA by the electrostatic force between the nanoparticles, but also significantly delayed the release of VEGF-A. In addition, Lap promoted high expression of osteogenic biomarkers in mesenchymal stem cells (MSCs) and enhanced the matrix mineralization. Besides, VEGF-A exerted chemotactic effects recruiting endothelial progenitor cells (EPCs) and inducing neovascularization. Histological and micro-CT results demonstrated that the critical-sized calvarial bone defect lesions in the SD rats after treated with G@Lap/VEGF exhibited significant in vivo bone repairing. In conclusion, the injectable G@Lap/VEGF nanocomposite hydrogel constructed in our study is highly promising for clinical transformation and applications, providing a convenient and simplified scheme for clinical bone repairing, and contributing to the further development of the injectable biomimetic hydrogels.

HIV Modulates Osteoblast Differentiation via Upregulation of RANKL and Vitronectin.

Bone loss is a prevalent characteristic among people with HIV (PWH). We focused on mesenchymal stem cells (MSCs) and osteoblasts, examining their susceptibility to different HIV strains (R5- and X4-tropic) and the subsequent effects on bone tissue homeostasis. Our findings suggest that MSCs and osteoblasts are susceptible to R5- and X4-tropic HIV but do not support productive HIV replication. HIV exposure during the osteoblast differentiation process revealed that the virus could not alter mineral and organic matrix deposition. However, the reduction in runt-related transcription factor 2 (RUNX2) transcription, the increase in the transcription of nuclear receptor activator ligand kappa B (RANKL), and the augmentation of vitronectin deposition strongly suggested that X4- and R5-HIV could affect bone homeostasis. This study highlights the HIV ability to alter MSCs' differentiation into osteoblasts, critical for maintaining bone and adipose tissue homeostasis and function.

Bone mechanical properties were altered in a mouse model of multiple myeloma bone disease

Multiple myeloma bone disease (MMBD) is characterized by the growth of malignant plasma cells in bone marrow, leading to an imbalance in bone (re)modeling favoring excessive resorption. Loss of bone mass and altered microstructure characterize MMBD in humans and preclinical animal models, although, no study to date has examined bone composition or material properties. We hypothesized that MMBD alters bone composition, mineral crystal properties and mechanical properties in the MOPC315.BM.Luc model after intra-tibial injection of myeloma cells and three weeks of daily in vivo tibial loading. Decreased cortical bone elastic modulus and hardness measured by nanoindentation of tibiae were observed in MM-injected mice compared to PBS-injected mice, whereas cortical bone composition, mineral crystal properties measured by Fourier-transform infrared imaging or small angle X-ray scattering, respectively remained unchanged. However, MM-injected mice had thinner cancellous bone mineral particles compared to PBS-injected mice. Mechanical loading did not lead to altered cortical bone composition, mineral structure, or mechanical properties in the context of MM. Unexpectedly, we observed the intra-tibial injection itself altered the material composition of bone, manifested by increased matrix mineralization and crystal size of the hydroxyapatite crystals in the bone matrix. In conclusion, our data suggest that mechanical stimuli can be used as an adjuvant bone anabolic therapy in patients with MMBD to rebuild bone with unaltered composition and mineral structure to reduce subsequent fracture risk.

Sex-Specific Association of Clinical Parameters and Components of Femoral Bone Quality in Patients Undergoing Total Hip Arthroplasty.

Poor bone quality is a critical factor associated with an increased risk of complications after total hip arthroplasty (THA). However, no consistent recommendations have yet been established for assessing indicators of bone quality preoperatively. Thus, it remains unclear which preoperatively available and readily accessible parameters are most closely associated with femoral bone quality. Here, we obtained femoral neck specimens from 50 patients undergoing THA. Preoperative Dual-energy X-ray absorptiometry (DXA) scans, pelvic radiographs, and laboratory parameters were analyzed. In the obtained specimens, bone microstructure was assessed using micro-CT and histomorphometry. Additionally, matrix mineralization and osteocyte lacunar morphology were evaluated using quantitative backscattered electron imaging. Our analysis revealed that DXA-derived T-scores correlated with trabecular microstructure. Furthermore, radiographic indices and body mass index correlated differentially with aspects of bone quality in women and men. Contrary to previous observations, no correlation was found between serum vitamin D levels and osteoid indices, nor between clinical parameters and matrix mineralization. Age was strongly associated with the number of mineralized osteocyte lacunae, a factor that appeared to be independent of sex. Taken together, our study demonstrates that no single preoperatively available parameter exhibits a strong and consistent association with femoral bone quality. However, DXA remains a reliable preoperative measure for determining the trabecular microstructure of the femoral neck. In clinical practice, surgeons should adopt an individualized approach to preoperative assessments by considering age, sex, BMI, and radiographic indices to enhance their insight into femoral bone quality, particularly when DXA is unavailable.