Search Results (383)

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. Full article

Background: Extracellular vesicles (EVs) derived from stem cells demonstrate significant potential in bone regeneration. Adipose tissue is regarded as a stem cell reservoir with abundant reserves and easy accessibility. Compared to adipose-derived stem cells (ASCs), dedifferentiated fat cells (DFATs) possess similar stem cell characteristics but exhibit greater proliferative capacity, higher homogeneity, and an enhanced osteogenic differentiation potential. This study is the first to examine the effect of DFATs-derived EVs on bone regeneration and elucidate their potential mechanisms of action. Methods: Primary DFATs were cultured using the “ceiling culture” method and EVs were isolated by ultracentrifugation and characterized. Experiments were performed to assess the impact of the EVs on the proliferation, migration, and osteogenesis of bone marrow mesenchymal stem cells (BMSCs). Subsequently, high-throughput miRNA sequencing was conducted on the EVs derived from DFATs that had undergone 0 days (0d-EVs) and 14 days (14d-EVs) of osteogenic differentiation. Results: The results indicated that the EVs derived from DFATs which experienced 14 days of osteogenic induction significantly promoted the proliferation, migration, and osteogenic differentiation of BMSCs. High-throughput sequencing results revealed that up-regulated miRNAs in the 14d-EVs were primarily involved in biological processes such as the Notch signaling pathway and the positive regulation of cell movement and migration. The target genes of these differently expressed miRNAs were enriched in osteogenesis-related signaling pathways. Conclusion: This study innovatively demonstrated that conditioned EVs (14d-EVs) derived from DFATs promoted the osteogenic differentiation of BMSCs via miRNAs, offering a promising cell-free therapeutic option for bone defect. Full article

The biological products used in orthopedics include musculoskeletal allografts—such as bones, tendons, ligaments, and cartilage—as well as biological therapies. Musculoskeletal allografts support the body’s healing process by utilizing preserved and sterilized donor tissue. These allografts are becoming increasingly common in surgical practice, allowing patients to avoid more invasive procedures and the risks associated with donor site morbidity. Bone grafting is one of the most frequently used procedures in orthopedics and traumatology. Biologic approaches aim to improve clinical outcomes by enhancing the body’s natural healing capacity and reducing inflammation. They serve as an alternative to surgical interventions. While preliminary results from animal studies and small-scale clinical trials have been promising, the field of biologics still lacks robust clinical evidence supporting their efficacy. Biological therapies include PRP (platelet-rich plasma), mesenchymal stem cells (MSCs)/stromal cells/progenitor cells, bone marrow stem/stromal cells (BMSCs), adipose stem/stromal cells/progenitor cells (ASCs), cord blood (CB), and extracellular vesicles (EVs), including exosomes. The proper preservation and storage of these cellular therapies are essential for future use. Preservation techniques include cryopreservation, vitrification, lyophilization, and the use of cryoprotective agents (CPAs). The most commonly used CPA is DMSO (dimethyl sulfoxide). The highest success rates and post-thaw viability have been achieved by preserving PRP with a rate-controlled freezer using 6% DMSO and storing other cellular treatments using a rate-controlled freezer with 5% or 10% DMSO as the CPA. Extracellular vesicles (EVs) have shown the best results when lyophilized with 50 mM or 4% trehalose to prevent aggregation and stored at room temperature. Full article

Human osteosarcoma (OS) is a rare tumor predominantly affecting long bones and characterized by a poor prognosis. Currently, the first line of intervention consists of the surgical resection of primary tumors combined with radiotherapy and chemotherapy, with a profound impact on the patient’s life. Since the surgical removal of OS frequently results in a large resection of bones, the use of biomaterials to sustain the stability of the remaining tissue and to stimulate bone regeneration is challenging. Moreover, residual neoplastic cells might be responsible for tumor recurrence. Here, we explored the potential of tellurium-ion-doped bioactive glass as a novel therapeutic intervention to both eradicate residual malignant cells and promote bone regeneration. Bioactive glass (BAG) has been extensively studied and employed in the field of regenerative medicine due to its osseointegration properties and ability to improve bone tissue regeneration. We found that the incorporation of tellurium (Te) in BAG selectively kills OS cells through ferroptosis while preserving the viability of hBMSCs and stimulating their osteodifferentiation. However, the mechanism of Te toxicity is still unclear: (i) Te-BAG generates lipid-ROS through LOXs activity but not iron overload; (ii) Te-dependent ferroptosis is mediated by GPX4 down-regulation; and (iii) the anti-ferroptotic activity of FSP1 is abrogated, whose expression confers the resistance of OS to the canonical induction of ferroptosis. Overall, our data show that Te-doped bioglass could represent an interesting biomaterial with both pro-ferroptotic activity towards residual cancer cells and pro-osteoregenerative activity. Full article

The effects of the hydrogen sulfide (H₂S) slow-releasing donor, named GSGa, a glutathione-conjugate water-soluble garlic extract, on human mesenchymal stem cells (hMSCs) in both bidimensional (2D) and three-dimensional (3D) cultures were investigated, demonstrating increased expression of the antioxidant enzyme HO-1 and decreased expression of the pro-inflammatory cytokine interleukin-6 (IL-6). The administration of the H₂S donor can therefore increase the expression of antioxidant enzymes, which may have potential therapeutic applications in osteoarthritis (OA). Moreover, GSGa was able to promote the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), but not of cardiac mesenchymal stem cells (cMSCs) in a 2D culture system. This result highlights the varying sensitivity of hMSCs to the H₂S donor GSGa, suggesting that the induction of osteogenic differentiation in stem cells by chemical factors is dependent on the tissue of origin. Additionally, a 3D-printable mesenchymal stem cells–bone matrix array (MSCBM), designed to closely mimic the stiffness of bone tissue, was developed to serve as a versatile tool for evaluating the effects of drugs and stem cells on bone repair in chronic diseases, such as OA. We demonstrated that the osteogenic differentiation process in cMSCs can be induced just by simulating bone stiffness in a 3D system. The expression of osteocalcin, RUNX2, and antioxidant enzymes was also assessed after treating MSCs with GSGa and/or increasing the stiffness of the culture environment. The printability of the array may enable better customization of the cavities, enabling an accurate replication of real bone defects. This could optimize the BM array to mimic bone defects not only in terms of stiffness, but also in terms of shape. This culture system may enable a rapid screening of antioxidant and anti-inflammatory compounds, facilitating a more personalized approach to regenerative therapy. Full article

Bone marrow and teeth contain mesenchymal stem cells (MSCs) that could be used for cell-based regenerative therapies. MSCs from these two tissues represent heterogeneous cell populations with varying degrees of lineage commitment. Although human bone marrow stem cells (hBMSCs) and human dental pulp stem cells (hDPSCs) have been extensively studied, it is not yet fully defined if their adipogenic potential differs. Therefore, in this study, we compared the in vitro adipogenic differentiation potential of hDPSCs and hBMSCs. Both cell populations were cultured in adipogenic differentiation media, followed by specific lipid droplet staining to visualise cytodifferentiation. The in vitro differentiation assays were complemented with the expression of specific genes for adipogenesis and osteogenesis–dentinogenesis, as well as for genes involved in the Wnt and Notch signalling pathways. Our findings showed that hBMSCs formed adipocytes containing numerous and large lipid vesicles. In contrast to hBMSCs, hDPSCs did not acquire the typical adipocyte morphology and formed fewer lipid droplets of small size. Regarding the gene expression, cultured hBMSCs upregulated the expression of adipogenic-specific genes (e.g., PPARγ2, LPL, ADIPONECTIN). Furthermore, in these cells most Wnt pathway genes were downregulated, while the expression of NOTCH pathway genes (e.g., NOTCH1, NOTCH3, JAGGED1, HES5, HEY2) was upregulated. hDPSCs retained their osteogenic/dentinogenic molecular profile (e.g., RUNX2, ALP, COLIA1) and upregulated the WNT-specific genes but not the NOTCH pathway genes. Taken together, our in vitro findings demonstrate that hDPSCs are not entirely committed to the adipogenic fate, in contrast to the hBMSCs, which are more effective to fully differentiate into adipocytes. Full article

Treatment of articular cartilage remains a great challenge due to its limited self-repair capability. In tissue engineering, a scaffold with both mechanical strength and regenerative capacity has been highly desired. This study developed a double-network scaffold based on natural biomaterials of silk fibroin (SF) and methacrylated hyaluronic acid (MAHA) using three-dimensional (3D) printing technology. Structural and mechanical characteristics of the scaffold was first investigated. To enhance its ability of recruiting endogenous bone marrow mesenchymal stem cells (BMSCs), the scaffold was conjugated with a proven BMSC-specific-affinity peptide E7, and its biocompatibility and capacity of cell recruitment were assessed in vitro. Animal experiments were conducted to evaluate cartilage regeneration after transplantation of the described scaffolds. The SF/HA scaffolds exhibited a hierarchical macro-microporous structure with ideal mechanical properties, and offered a 3D spatial microenvironment for cell migration and proliferation. In vitro experiments demonstrated excellent biocompatibility of the scaffolds to support BMSCs proliferation, differentiation, and extracellular matrix production. In vivo, superior capacity of cartilage regeneration was displayed by the SF/MAHA + E7 scaffold as compared with microfracture and unconjugated SF/MAHA scaffold based on macroscopic, histologic and imaging evaluation. In conclusion, this structurally and functionally optimized SF/MAHA + E7 scaffold may provide a promising approach to repair articular cartilage lesions in situ. Full article

Magnesium alloy ZK60 shows great promise as a medical metal material, but its corrosion resistance in the body is inadequate. Hydroxyapatite (HA), the primary inorganic component of human and animal bones, can form chemical bonds with body tissues at the interface, promoting the deposition of phosphorus products and creating a dense calcium and phosphorus layer. To enhance the properties of ZK60, HA was added to create HA/ZK60 composite materials. These composites, fabricated using the advanced technique of LPBF, demonstrated superior corrosion resistance and enhanced bone inductive capabilities compared to pristine ZK60. Notably, the incorporation of 3 wt% led to a significant reduction in bulk porosity, achieving a value of 0.8%. The E_corr value increased from −1.38 V to −1.32 V, while the minimum I_corr value recorded at 33.9 μA·cm⁻². Nano-HA achieved the lowest volumetric porosity and optimal corrosion resistance. Additionally, these composites significantly promoted osteogenic differentiation in bone marrow stromal cells (BMSCs), as evidenced by increased alkaline phosphatase (ALP) activity and robust calcium nodule formation, highlighting their excellent biocompatibility and osteo-inductive potential. However, when increasing the HA content to 6 wt%, the bulk porosity rose significantly to 3.3%. The E_corr value was −1.3 V, with the I_corr value being approximately 50 μA·cm⁻². This increase in porosity and weaker interfacial bonding, ultimately accelerated electrochemical corrosion. Therefore, a carefully balanced amount of HA significantly enhances the performance of the ZK60 magnesium alloy, while excessive amounts can be detrimental. Full article

Endochondral ossification is the process by which cartilage is mineralized into bone, and is essential for the development of long bones. Osteocalcin (OCN), a protein abundant in bone matrix, also exhibits high expression in chondrocytes, especially hypertrophic chondrocytes, while its role in endochondral ossification remains unclear. Utilizing a new CRISPR/Cas9-mediated bglap–bglap2 deficiency (OCN^em) mouse model generated in our laboratory, we provide the first evidence of OCN’s regulatory function in chondrocyte differentiation and endochondral ossification. The OCN^em mice exhibited significant delays in primary and secondary ossification centers compared to wild-type mice, along with increased cartilage length in growth plates and hypertrophic zones during neonatal and adolescent stages. These anomalies indicated that OCN deficiency disturbed endochondral ossification during embryonic and postnatal periods. Mechanism wise, OCN deficiency was found to increase chondrocyte differentiation and postpone vascularization process. Furthermore, bone marrow mesenchymal stromal cells (BMSCs) from OCN^em mice demonstrated an increased capacity for chondrogenic differentiation. Transcriptional network analysis implicated that BMP and TGF-β signaling pathways were highly affected in OCN^em BMSCs, which is closely associated with cartilage development and maintenance. This elucidation of OCN’s function in chondrocyte differentiation and endochondral ossification contributes to a more comprehensive understanding of its impact on skeletal development and homeostasis. Full article

The study aimed to develop a biodegradable scaffold incorporating valproic acid (VPA) for improved human bone marrow-derived mesenchymal stem cell (hBMSC) proliferation, differentiation, and bone mineral synthesis. A chitosan–gelatin (CH-G) scaffold was fabricated and loaded with varying concentrations of VPA (1, 3, 5 mM/L). In vitro studies assessed drug release, cell proliferation, morphology, mineralization, and gene expression. VPA was rapidly released from the scaffold, with over 90% cumulative release within seven days. Cells cultured on VPA-loaded scaffolds exhibited significantly enhanced proliferation and mineralization compared to the control. VPA treatment upregulated osteocalcin and runt-related transcription factor 2 (Runx-2) expression, key markers of osteogenic differentiation. The CH-G scaffold, particularly with 1 mM/L VPA, demonstrates excellent biocompatibility and promotes hBMSC-mediated bone regeneration. This novel approach holds promise for future applications in bone tissue engineering. Full article

This study aimed to decipher the influence of red mud on the mechanical properties, pore structure, and microstructure of basic magnesium sulfate cements (BMSCs). The results showed that BMSC prepared with an appropriate addition of red mud exhibited improved mechanical properties and yielded the highest compressive strength of 94.54 MPa after curing for 28 days. Adding red mud reduced the total porosity and optimized the pore structure of BMSC. The microstructure and hydration products of the specimens were examined using X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. The results illustrate that the addition of 50% red mud did not affect the amount of the main strength phase 5-1-7 produced in BMSC. It could also reduce the residual amount of MgO and the generation of Mg(OH)₂. The red mud and the M-S-H gel generated by the reaction between active SiO₂ and α-MgO in the red mud together filled the pore structure of BMSC, making its microstructure denser and higher-strength. This study aims to improve the comprehensive use of red mud, and the results show that red mud can improve the mechanical properties of BMSCs, protecting the environment and simultaneously reducing BMSC production costs to create good economic benefits. Full article

Uremic toxins cause bone disorders in patients with chronic kidney disease (CKD). These disorders are characterized by low turnover osteodystrophy and impaired bone formation in the early stages of CKD. Evidence indicates that the aryl hydrocarbon receptor (AhR) mediates signals that suppress early osteogenic differentiation in bone marrow mesenchymal stem cells (BMSCs). However, whether the AhR mediates the effects of indoxyl sulfate (IS), a uremic toxin, on BMSC osteogenesis remains unclear. We investigated whether IS affects osteogenesis through the AhR/Hes1 pathway. Expression levels of osteogenesis genes (Runx2, Bmp2, Alp, and Oc), AhR, and Hes1 were measured in mouse BMSCs (D1 cells). At concentrations of 2–50 μM, IS significantly reduced mineralization, particularly in the early stages of BMSC osteogenesis. Furthermore, IS significantly downregulated the expression of Runx2, Bmp2, Oc, and Alp. Notably, this downregulation could be prevented using an AhR antagonist and through Ahr knockdown. Mechanistically, IS induced the expression of Hes1 through AhR signaling, thereby suppressing the transcription of Runx2 and Bmp2. Our findings suggest that IS inhibits early osteogenesis of BMSCs through the AhR/Hes1 pathway, thus suppressing the transcription of Runx2 and Bmp2. Our findings may guide new therapeutic strategies against CKD-related bone disorders. Full article

This study investigated gelatin methacryloyl (GelMA) and polycaprolactone (PCL) blend scaffolds incorporating cerium oxide (CeO) nanoparticles at concentrations of 0%, 5%, and 10% w/w via electrospinning for periodontal tissue engineering. The impact of photocrosslinking on these scaffolds was evaluated by comparing crosslinked (C) and non-crosslinked (NC) versions. Methods included Fourier transform infrared spectroscopy (FTIR) for chemical analysis, scanning electron microscopy (SEM) for fiber morphology/diameters, and assessments of swelling capacity, degradation profile, and biomechanical properties. Biological evaluations with alveolar bone-derived mesenchymal stem cells (aBMSCs) and human gingival fibroblasts (HGFs) encompassed tests for cell viability, mineralized nodule deposition (MND), and collagen production (CP). Statistical analysis was performed using Kruskal–Wallis or ANOVA/post-hoc tests (α = 5%). Results indicate that C scaffolds had larger fiber diameters (~250 nm) compared with NC scaffolds (~150 nm). NC scaffolds exhibited higher swelling capacities than C scaffolds, while both types demonstrated significant mass loss (~50%) after 60 days (p < 0.05). C scaffolds containing CeO showed increased Young’s modulus and tensile strength than NC scaffolds. Cells cultured on C scaffolds with 10% CeO exhibited significantly higher metabolic activity (>400%, p < 0.05) after 7 days among all groups. Furthermore, CeO-containing scaffolds promoted enhanced MND by aBMSCs (>120%, p < 0.05) and increased CP in 5% CeO scaffolds for both variants (>180%, p < 0.05). These findings underscore the promising biomechanical properties, biodegradability, cytocompatibility, and enhanced tissue regenerative potential of CeO-loaded GelMA/PCL scaffolds for periodontal applications. Full article

The limited self-repair capacity of articular cartilage is a challenge for healing injuries. While mesenchymal stem/stromal cells (MSCs) are a promising approach for tissue regeneration, the criteria for selecting a suitable cell source remain undefined. To propose a molecular criterion, dental pulp stem cells (DPSCs) with a Hox-negative expression pattern and bone marrow mesenchymal stromal cells (BMSCs), which actively express Hox genes, were differentiated towards chondrocytes in 3D pellets, employing a two-step protocol. The MSCs’ response to preconditioning by cobalt chloride (CoCl₂), a hypoxia-mimicking agent, was explored in an assessment of the chondrogenic differentiation’s efficiency using morphological, histochemical, immunohistochemical, and biochemical experiments. The preconditioned DPSC pellets exhibited significantly elevated levels of collagen II and glycosaminoglycans (GAGs) and reduced levels of the hypertrophic marker collagen X. No significant effect on GAGs production was observed in the preconditioned BMSC pellets, but collagen II and collagen X levels were elevated. While preconditioning did not modify the ALP specific activity in either cell type, it was notably lower in the DPSCs differentiated pellets compared to their BMSCs counterparts. These results could be interpreted as demonstrating the higher plasticity of DPSCs compared to BMSCs, suggesting the contribution of their unique molecular characteristics, including their negative Hox expression pattern, to promote a chondrogenic differentiation potential. Consequently, DPSCs could be considered compelling candidates for future cartilage cell therapy. Full article

As one of the raw materials of basic magnesium sulfate cement (BMSC), the activity of light-burned magnesium oxide (MgO) has an important effect on the hydration rate, hydration products, and mechanical properties of BMSC. To reveal the influence of packaging method, storage environment, and storage time on the activity of MgO and the mechanical properties of BMSC, an experiment was conducted by using ordinary woven bags, peritoneal woven bags, and plastic and paper compound bags to store the finished BMSC and the raw materials (light-burned MgO, MgSO₄·7H₂O, fly ash, and a chemical additive) under the conditions of natural environment, sealed environment, and wet environment, respectively. Comparative analysis of the effects of packaging method, storage conditions, and storage time on the activity of MgO and the mechanical properties of BMSC was performed through the mechanical strength test of mortar specimens. The results showed that in a sealed environment, the loss of a-MgO content in light-burned MgO was minimized, which was more conducive to keeping the mechanical properties of BMSC stable. In the wet environment, the mechanical strength of BMSC was significantly reduced in the early stage (1 day) due to the significant reduction in the activity of MgO, and the mechanical strength of the finished BMSC and prepared BMSC after 120 days of storage was still lost, regardless of the packaging method. However, the storage environment and packaging method had relatively little effect on the late mechanical strength (28 days) of BMSC. It is advisable to use ordinary woven bags for packaging in natural and sealed environments as this is more economical for engineering applications. Plastic and paper compound bags are superior to ordinary woven bags and peritoneal woven bags in wet environments. Full article