Osteogenic Differentiation Capability Research Articles

Functionalized 3D-printed GelMA/Laponite hydrogel scaffold promotes BMSCs recruitment through osteoimmunomodulatory enhance osteogenic via AMPK/mTOR signaling pathway

The migration and differentiation of bone marrow mesenchymal stem cells (BMSCs) play crucial roles in bone repair processes. However, conventional scaffolds often lack of effectively inducing and recruiting BMSCs. In our study, we present a novel approach by introducing a 3D-bioprinted scaffold composed of hydrogels, with the addition of laponite to the GelMA solution, aimed at enhancing scaffold performance. Both in vivo and in vitro experiments have confirmed the outstanding biocompatibility of the scaffold. Furthermore, for the first time, Apt19s has been chemically modified onto the surface of the hydrogel scaffold, resulting in a remarkable enhancement in the migration and adhesion of BMSCs. Moreover, the scaffold has demonstrated robust osteogenic differentiation capability in both in vivo and in vitro environments. Additionally, the hydrogel scaffold has shown the ability to induce the polarization of macrophages from M1 to M2, thereby facilitating the osteogenic differentiation of BMSCs via the bone immune pathway. Through RNA-seq analysis, it has been revealed that macrophages regulate the osteogenic differentiation of BMSCs through the AMPK/mTOR signaling pathway. In summary, the functionalized GelMA/Laponite scaffold offers a cost-effective approach for tailored in situ bone regeneration.

Hydrogel Microsphere-Encapsulated Bimetallic Nanozyme for Promoting Diabetic Bone Regeneration via Glucose Consumption and ROS Scavenging.

The healing of bone defects among diabetic patients presents a critical challenge due to the pathological microenvironment, characterized by hyperglycemia, excessive reactive oxygen species (ROS) production, and inflammation. Herein, multifunctional composite microspheres, termed GMAP are developed, using a microfluidic technique by incorporating Au@Pt nanoparticles (NPs) and GelMA hydrogel to modulate the diabetic microenvironment for promoting bone regeneration. The GMAP enables the sustained release of Au@Pt NPs, which function as bimetallic nanozymes with dual enzyme-like activities involving glucose oxidase and catalase. The synergistic effect allows for efficient glucose consumption and ROS elimination concurrently. Thus, the GMAP effectively protects the proliferation of bone marrow mesenchymal stem cells (BMSCs) under adverse high-glucose conditions. Furthermore, it also promotes the osteogenic differentiation and paracrine capabilities of BMSCs, and subsequently inhibits inflammation and enhances angiogenesis. In vivo diabetic rats bone defect model, it is demonstrated that GMAP microspheres significantly improve bone regeneration, as verified by micro-computed tomography and histological examinations. This study provides a novel strategy for bone regeneration by modulating the diabetic microenvironment, presenting a promising approach for addressing the complex challenges associated with bone healing in diabetic patients.

Osteogenic differentiation capabilities of multiarm PEG hydrogels: involvement of gel–gel-phase separation in cell differentiation

AbstractThe development of bioactive scaffolds is essential for tissue engineering because of the influence of material physicochemical properties on cellular activities. Recently, we discovered that percolation-induced 4-arm polyethylene glycol (PEG) hydrogels achieved gel–gel phase separation (GGPS), which has tissue affinity in vivo. However, whether the 4-arm structure is the optimal configuration for the use of PEG hydrogels as scaffolds remains unclear. In this study, we investigated the effect of an increased branching factor on GGPS. Compared with the 4-arm PEG hydrogel, the 8-arm PEG hydrogel presented a greater degree of GGPS and increased hydrophobicity. We introduced the RGD sequence into PEG hydrogels to directly assess the biological activity of GGPS, with a particular focus on its effects on the activity of bone-forming osteoblasts. Although the 8-arm PEG hydrogel did not enhance cell adhesion, it enhanced osteoblast differentiation compared with the 4-arm PEG hydrogel. Therefore, the 8-arm PEG hydrogel mediated by GGPS shows promise as a scaffold for osteoblast differentiation and holds potential as a foundation for future advancements in bone tissue engineering.

Improvement of biological and corrosion behavior of plasma electrolytic oxidized Mg implant by 3D printed scaffold of amine-terminated PEG/PCL loaded with dexamethasone

Although magnesium-based implants have good biocompatibility and biodegradability, they suffer from rapid corrosion in the body environment, which limits their biomedical applications. This study represents an approach for designing a bioactive and anti-corrosive hybrid structure composed of an inorganic layer by plasma electrolytic oxidation process and an organic layer of 3D printed polycaprolactone and amine-terminated polyethylene glycol scaffold containing dexamethasone. The results indicated that the hybrid layer exhibited superior adhesion strength, high corrosion resistance, remarkable biocompatibility, cell attachment, and osteogenic differentiation. The dexamethasone released from the 3D printed scaffold revealed high osteogenic differentiation capability. Hence, the fabrication of plasma electrolytic oxidized interlayer with a 3D printed scaffold can be a novel platform to preserve the magnesium-based biological implants from corrosion and to regenerate bone along with the controlled release of osteogenic components.

Insulin promotes the bone formation capability of human dental pulp stem cells through attenuating the IIS/PI3K/AKT/mTOR pathway axis

BackgroundInsulin has been known to regulate bone metabolism, yet its specific molecular mechanisms during the proliferation and osteogenic differentiation of dental pulp stem cells (DPSCs) remain poorly understood. This study aimed to explore the effects of insulin on the bone formation capability of human DPSCs and to elucidate the underlying mechanisms.MethodsCell proliferation was assessed using a CCK-8 assay. Cell phenotype was analyzed by flow cytometry. Colony-forming unit-fibroblast ability and multilineage differentiation potential were evaluated using Toluidine blue, Oil red O, Alizarin red, and Alcian blue staining. Gene and protein expressions were quantified by real-time quantitative polymerase chain reaction and Western blotting, respectively. Bone metabolism and biochemical markers were analyzed using electrochemical luminescence and chemical colorimetry. Cell adhesion and growth on nano-hydroxyapatite/collagen (nHAC) were observed with a scanning electron microscope. Bone regeneration was assessed using micro-CT, fluorescent labeling, immunohistochemical and hematoxylin and eosin staining.ResultsInsulin enhanced the proliferation of human DPSCs as well as promoted mineralized matrix formation in a concentration-dependent manner. 10− 6 M insulin significantly up-regulated osteogenic differentiation-related genes and proteins markedly increased the secretion of bone metabolism and biochemical markers, and obviously stimulated mineralized matrix formation. However, it also significantly inhibited the expression of genes and proteins of receptors and receptor substrates associated with insulin/insulin-like growth factor-1 signaling (IIS) pathway, obviously reduced the expression of the phosphorylated PI3K and the ratios of the phosphorylated PI3K/total PI3K, and notably increased the expression of the total PI3K, phosphorylated AKT, total AKT and mTOR. The inhibitor LY294002 attenuated the responsiveness of 10− 6 M insulin to IIS/PI3K/AKT/mTOR pathway axis, suppressing the promoting effect of insulin on cell proliferation, osteogenic differentiation and bone formation. Implantation of 10− 6 M insulin treated DPSCs into the backs of severe combined immunodeficient mice and the rabbit jawbone defects resulted in enhanced bone formation.ConclusionsInsulin induces insulin resistance in human DPSCs and effectively promotes their proliferation, osteogenic differentiation and bone formation capability through gradually inducing the down-regulation of IIS/PI3K/AKT/mTOR pathway axis under insulin resistant states.

Based on NF-κB and Notch1/Hes1 Signaling Pathways, the Mechanism of Artesunate on Inflammation in Osteoporosis in Ovariectomized Rats was Investigated.

Artesunate (ART) has the potential to modulate the nuclear factor kappa B (NF-κB) and Notch1/Hes1 signaling pathways, which play crucial roles in the pathogenesis of osteoporosis. This study aims to explore whether ART participates in the progression of osteoporosis by regulating these signaling pathways. In the in vitro experiments, we treated bone marrow mesenchymal stem cells (BMSCs) with different concentrations of ART (0, 3, 6, 12 µM) and evaluated osteogenic differentiation using alkaline phosphatase staining (ALP) and alizarin red S staining (ARS) staining. The expression levels of osteocalcin (OCN), RUNT-related transcription factor 2 (RUNX2), osteoprotegerin (OPG), and receptor activator of the nuclear factor kappa ligand (RANKL) were detected by real-time quantitative PCR (RT-qPCR). The effects of ART on NF-κB p65 and Notch1 protein expression were analyzed by Western blot (WB) and immunofluorescence (IF). In the in vivo experiments, a postmenopausal osteoporosis rat model was established via ovariectomy. Bone tissue pathological injury was evaluated using hematoxylin eosin (HE) staining. Serum ALP levels were measured using a kit, bone density was determined by dual-energy X-ray absorptiometry, and serum levels of bone gla protein (BGP), OPG, RANKL, tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), and IL-1β were measured by enzyme-linked immunosorbent assay (ELISA). Additionally, the expression of NF-κB p65 and Notch1 in tissues was assessed by immunohistochemistry. In vitro experiments revealed that compared to the control group, ART dose-dependently promoted BMSCs proliferation and enhanced their osteogenic differentiation capability. The expression of OCN, RUNX2, and OPG significantly increased in the ART-treated group, while RANKL expression decreased significantly (p < 0.05). ART significantly inhibited the expression of NF-κB p65 and Notch1/Hes1 signaling pathway proteins (p < 0.05). Compared to ART treatment alone, combined treatment with ART and phorbol myristate acetate (PMA) or valproic acid (VPA) resulted in increased expression of NF-κB p65 and Notch1 proteins and decreased osteogenic differentiation capability (p < 0.05). In vivo experiments showed that in rats treated with ART, bone damage was significantly reduced, bone density and mineral content were restored considerably, and the expression of inflammatory factors (TNF-α, IL-6, IL-1β) decreased significantly (p < 0.05). Additionally, ART treatment significantly reduced the expression of NF-κB p65 and Notch1 proteins, increased OPG expression, and decreased BGP and RANKL levels (p < 0.05). In summary, ART facilitates the osteogenic differentiation of BMSCs by inhibiting the NF-κB and Notch1/Hes1 signaling pathways, thereby exerting significant protective effects against osteoporosis.

Fabrication and Evaluation of PCL/PLGA/β-TCP Spiral-Structured Scaffolds for Bone Tissue Engineering.

Natural bone is a complex material that has been carefully designed. To prepare a successful bone substitute, two challenging conditions need to be met: biocompatible and bioactive materials for cell proliferation and differentiation, and appropriate mechanical stability after implantation. Therefore, a hybrid Poly ε-caprolactone/Poly(lactic-co-glycolide)/β-tricalcium phosphate (PCL/PLGA/β-TCP) scaffold has been introduced as a suitable composition that satisfies the above two conditions. The blended PCL and PLGA can improve the scaffold's mechanical properties and biocompatibility compared to single PCL or PLGA scaffolds. In addition, the incorporated β-TCP increases the mechanical strength and osteogenic potential of PCL/PLGA scaffolds, while the polymer improves the mechanical stability of ceramic scaffolds. The PCL/PLGA/β-TCP scaffold is designed using spiral structures to provide a much better transport system through the gaps between spiral walls than conventional cylindrical scaffolds. Human fetal osteoblasts (hFOBs) were cultured on spiral PCL/PLGA/β-TCP (PPBS), cylindrical PCL/PLGA/β-TCP (PPBC), and cylindrical PCL scaffolds for a total of 28 days. The cell proliferation, viability, and osteogenic differentiation capabilities were analyzed. Compared with PCL and PPBC scaffolds, the PPBS scaffold exhibits great biocompatibility and potential to stimulate cell proliferation and differentiation and, therefore, can serve as a bone substitute for bone tissue regeneration.

CRIP1 regulates osteogenic differentiation of bone marrow stromal cells and pre-osteoblasts via the Wnt signaling pathway

With the aging of the global demographic, the prevention and treatment of osteoporosis are becoming crucial issues. The gradual loss of self-renewal and osteogenic differentiation capabilities in bone marrow stromal cells (BMSCs) is one of the key factors contributing to osteoporosis. To explore the regulatory mechanisms of BMSCs differentiation, we collected bone marrow cells of femoral heads from patients undergoing total hip arthroplasty for single-cell RNA sequencing analysis. Single-cell RNA sequencing revealed significantly reduced CRIP1 (Cysteine-Rich Intestinal Protein 1) expression and osteogenic capacity in the BMSCs of osteoporosis patients compared to non-osteoporosis group. CRIP1 is a gene that encodes a member of the LIM/double zinc finger protein family, which is involved in the regulation of various cellular processes including cell growth, development, and differentiation. CRIP1 knockdown resulted in decreased alkaline phosphatase activity, mineralization and expression of osteogenic markers, indicating impaired osteogenic differentiation. Conversely, CRIP1 overexpression, both in vitro and in vivo, enhanced osteogenic differentiation and rescued bone mass reduction in ovariectomy-induced osteoporosis mice model. The study further established CRIP1's modulation of osteogenesis through the Wnt signaling pathway, suggesting that targeting CRIP1 could offer a novel approach for osteoporosis treatment by promoting bone formation and preventing bone loss.

The Contribution of Meckel's Cartilage-Derived Type II Collagen-Positive Cells to the Jawbone Development and Repair.

Jawbones and long bones, despite their shared skeletal lineage, frequently exhibit distinct origins and developmental pathways. Identifying specific progenitor subsets for mandibular osteogenesis remains challenging. Type II collagen is conventionally associated with cartilaginous structures, yet our investigation has identified the presence of type II collagen positive (Col2+) cells within the jawbone development and regeneration. The role of Col2+ cells in jawbone morphogenesis and repair has remained enigmatic. In this study, we analyze single-cell RNA sequencing data from mice jawbone at embryonic day 10.5. Through fate-mapping experiments, we have elucidated that Col2+ cells and their progeny are instrumental in mandibular osteogenesis across both fetal and postnatal stages. Furthermore, lineage tracing with a tamoxifen-inducible CreER system has established the pivotal role of Col2+ cells, marked by Col2-CreER and originating from the primordial Meckel's cartilage, in jawbone formation. Moreover, our research explored models simulating jawbone defects and tooth extraction, which underscored the osteogenic differentiation capabilities of postnatal Col2+ cells during repair. This finding not only highlights the regenerative potential of Col2+ cells but also suggests their versatility in contributing to skeletal healing and regeneration. In conclusion, our findings position Col2+ cells as essential in orchestrating osteogenesis throughout the continuum of mandibular development and repair.

Boswellic acid as a potential adjunct for bone healing after endodontic surgery: In vitro study

Abstract Introduction: The role of Acetyl -11-keto-β-boswellic acid (AKBA) in regulating osteoblast differentiation was recently brought to light. Therefore, the current study was designed to explore the osteogenic differentiation capability of AKBA on bone marrow mesenchymal stem cells (BMMSCs) as a potential therapeutic agent to accelerate the healing process in apicoectomy. Materials and Methods: BMMSCs were characterized by flow cytometry. Cellular viability and proliferation assays were used with different concentrations of AKBA. Cells were divided into 5 groups to test osteogenic differentiation: Group I: negative control, Group II: positive control, Group III: BMMSCs were treated with 1 μM AKBA, Group IV: BMMSCs were treated with 0.1 μM AKBA, and Group V: BMMSCs were treated with 0.01 μM AKBA. Mineralization assays and gene expression analysis were assessed, and the significance difference between groups was established at P &lt; 0.05. Results: The flow cytometry analysis demonstrated that BMMSCs had positive expression for mesenchymal stem cell marker and negative expression for hematopoietic markers. The concentration of 0.01 μM gave significantly higher cell density than the untreated cells after 7 days (P &lt; 0.05). Cells treated with 0.1 and 0.01 μM AKBA revealed a significantly higher ALP activity, alizarin red, and von Kossa staining than control groups (P &lt; 0.05). High expression of osteogenic genes was detected in BMMSCs treated with 0.1 μM AKBA (P &lt; 0.05). Conclusions: It was declared that the concentration of 0.1 μM AKBA has no toxicity on BMMSC viability and proliferation with an impact on BMMSC osteogenic differentiation. Therefore, AKBA (0.01 μM) could be used in bone regeneration during periradicular surgery.

The effect of cigarette and e-cigarette smoke on dental pulp stem cells proliferation capacity and differentiation [in vitro study

BackgroundMesenchymal stem cells (MSCs) have long been known for their ability to regenerate tissue. Cigarette smoking is one environmental risk factor that may impair the performance of MSCs. Electronic cigarettes have recently become a popular and widely accepted alternative to tobacco cigarettes due to their safety. The present study aims to analyze how smoke extracts of cigarette tobacco and electronic cigarettes affect the capability of dental pulp stem cell (DPSCs) proliferation and osteogenic differentiation. In this study, DPSCs were isolated from healthy impacted third molars of non-smokers, and two smoke extracts were made from tobacco powder and electronic cigarettes. Half maximal inhibitory concentration (IC50) was calculated at two time intervals (14 and 21 days), and its effect on the proliferation and osteogenic differentiation of the DPSCs was assessed.ResultsThe proliferation rate with the calculated IC50 of both smoke extracts was reduced compared to control cells. After 21 days of osteogenic induction, significantly fewer calcium deposits were visible among cells exposed to both smoke extracts. In addition, the expression of alkaline phosphatase and RANKL proteins was significantly reduced in differentiated DPSCs subjected to both smoke extracts.ConclusionsDPSCs exposed to both smoke extracts showed decreased cell viability and osteogenic differentiation potentiality compared to control cells. Smoking in any form has a detrimental effect on the proliferation and regenerative capacity of MSCs.

Mogroside V Promotes Osteogenic Differentiation of Bone Marrow Mesenchymal Stem Cells from Diabetic Mice by Altering MicroRNA Profiles.

Mogroside V (MV), a triterpene glycoside, exhibits diverse biological functions. However, its ability to promote the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) under diabetic conditions is yet to be elucidated. To study the regulation of osteogenic differentiation of BMSCs in diabetic mice by MV and determine the potential mechanism. BMSCs were isolated from both normal (referred to as N-BMSCs) and diabetic (referred to as DM-BMSCs) C57BL/6 mice. DM-BMSCs were treated with different concentrations of MV for varying durations, and cell viability was detected using the cell counting kit-8 assay. Following 2 weeks of osteogenic induction, osteogenic differentiation capability was evaluated using alizarin red S staining, alkaline phosphatase (ALP) activity analysis, and quantitative real-time reverse transcription polymerase chain reaction. Furthermore, the microRNA (miRNA) expression profiles of N-BMSCs, DM-BMSCs, and DM-BMSCs treated with MV were tested using high-throughput sequencing. Treatment with MV enhanced the viability of DM-BMSCs and mitigated the reduction of calcium nodule deposition, ALP activity, and mRNA expression of ALP, osteocalcin, and runt-related transcription factor 2. Of the analyzed miRNAs, miR-10b-5p was the only one that exhibited differential expression in N-BMSCs, DM-BMSCs, and DM-BMSCs treated with MV. An analysis of the top four protein clusters based on KEGG suggested that the target genes of differentially expressed miRNAs were closely linked to the PI3K/AKT pathway. MV significantly enhances the viability and osteogenic differentiation of BMSCs under diabetic conditions. The alteration of miRNA profiles provides a foundation for further research into the regulatory role of miRNAs and MV in this process.

Remnant polarization and structural arrangement in P(VDF-TrFE) electrospun fiber meshes affect osteogenic differentiation of human mesenchymal stromal cells

Many tissues and cells are influenced by mechano-electric stimulation, thus the application of piezoelectric materials has recently received considerable attention in tissue engineering. This report investigated electrospun fiber meshes based on poly(vinylidenefluoride-co-trifluoroethylene) [P(VDF-TrFE)] as instructive biomaterials for osteogenic differentiation of human mesenchymal stromal cells (hMSCs). The influence played by methyl ethyl ketone (MEK), used as a solvent in place of dimethylformamide (DMF)/acetone mixture, and the effect of rotating velocity of the electrospinning collector on fiber morphology, mechanical and piezoelectric properties were studied. The solvent had noticeable effects on morphology and piezoelectric properties of electrospun fibers, with MEK outperforming DMF/acetone. By increasing the collector velocity up to 4000 rpm, the fiber diameter reduced and the mutual alignment of the fibers increased, corresponding to enhanced mechanical properties and piezo-active β-phase content. However, as a consequence of the diverse mechanical properties of random and aligned fibrous architectures, which ultimately affected the piezoelectric properties, randomly-oriented fibers exhibited higher remnant piezoelectric properties (Vout and d31 piezoelectric coefficient) than aligned ones. On these scaffolds, hMSCs showed an excellent capability of early osteogenic differentiation, leading to high calcium production. Fiber surface topology, fiber mesh morphology and remnant piezoelectric properties played a determinant role on hMSC osteogenic commitment.

In-situ construction of bioactive nanostructures on Ti alloy surfaces through ultra-low concentration alkali treatment and low-temperature annealing

Osseointegration is crucial for the long-term stability of orthopedic implants. Nanosurfacing can impart osteoinductivity to the implant. However, the application potential of most available nanotechnologies in surface modification of implants is limited, and there is an urgent need to develop new effective nanosurfacing techniques with greater practicality. In this study, we for the first time, utilized an ultra-low concentration NaOH solution (0.55 mM) combined with low-temperature annealing to achieve solid-state dewetting (SSD) on Ti alloy surfaces, resulting in well-defined TiO2 nanoisland-like crystals. In vitro cell experiments demonstrated that the constructed nanostructures significantly affected the adhesion, proliferation, and osteogenic differentiation capability of MC3T3-E1 cells. The nanostructures formed at 550 °C exhibited the most pronounced enhancement of cell osteogenic differentiation capability. This method is simple, easy to operate, and scalable, holding significant application potential in the surface modification of Ti alloys.

Dynamic regulation of stem cell adhesion and differentiation on degradable piezoelectric poly (L-lactic acid) (PLLA) nanofibers.

Degradable piezoelectric materials possess significant potential for application in the realm of bone tissue regeneration. However, the correlation between cell regulation mechanisms and the dynamic variation caused by material degradation has not been explained, hindering the optimization of material design and its in vivo application. Herein, piezoelectric poly (L-lactic acid) (PLLA) nanofibers with different molecular weights (MW) were fabricated, and the effects of their piezoelectric properties, structural morphology, and material products during degradation on the adhesion and osteogenic differentiation of mesenchymal stem cells (MSCs) were investigated. Our results demonstrated that cell adhesion-mediated piezoelectric stimulation could significantly enhance cell spreading, cell orientation, and upregulate the expression of calmodulin, which further triggers downstream signaling cascade to regulate osteogenic differentiation markers of type I collagen and runt-related transcription factor 2. Additionally, during the degradation of the nanofibers, the piezoelectric properties of PLLA weakened, the fibrous structure gradually diminished, and pH levels in the vicinity decreased, which resulting in reduced osteogenic differentiation capability of MSCs. However, nanofibers with higher MW (280kDa) have the ability to maintain the fibrous morphology and piezoelectricity for a longer time, which can regulate the osteogenic differentiation of stem cells for more than 4 weeks. These findings have provide a new insight to correlate cell behavior with MW and the biodegradability of piezopolymers, which revealed an active method for cell regulation through material optimization for bone tissue engineering in near future.

Isolation, identification and osteogenic capability analysis of mesenchymal stem cells derived from different layers of human maxillary sinus membrane.

To discover the populations of mesenchymal stem cells (MSCs) derived from different layers of human maxillary sinus membrane (hMSM) and evaluate their osteogenic capability. hMSM was isolated into a monolayer using the combined method of physical separation and enzymatic digestion. The localization of MSCs in hMSM was performed by immunohistological staining and other techniques. Lamina propria layer-derived MSCs (LMSCs) and periosteum layer-derived MSCs (PMSCs) from hMSM were expanded using the explant cell culture method and identified by multilineage differentiation assays, colony formation assay, flow cytometry and so on. The biological characteristics of LMSCs and PMSCs were compared using RNA sequencing, reverse transcription and quantitative polymerase chain reaction, immunofluorescence staining, transwell assay, western blotting and so forth. LMSCs and PMSCs from hMSMs were both CD73-, CD90- and CD105-positive, and CD34-, CD45- and HLA-DR-negative. LMSCs and PMSCs were identified as CD171+/CD90+ and CD171-/CD90+, respectively. LMSCs displayed stronger proliferation capability than PMSCs, and PMSCs presented stronger osteogenic differentiation capability than LMSCs. Moreover, PMSCs could recruit and promote osteogenic differentiation of LMSCs. This study identified and isolated two different types of MSCs from hMSMs. Both MSCs served as good potential candidates for bone regeneration.

A biomimetic three-dimensional porous scaffold of mineralized recombinant collagen-sodium alginate for efficiently repairing critical-size cranial defects

The reconstruction of critical-size bone defects caused by trauma, tumor resection, and congenital anomalies remains a fundamental challenge in tissue engineering. Biomimetic scaffolds have received extensive attention for the discovery of advanced artificial bone substitutes due to their inherent biocompatibility and biodegradability. Herein, we have for the first time developed a biomimetic three-dimensional porous scaffold of mineralized recombinant collagen-sodium alginate (MRCSA) with supreme healing efficacy for critical-size cranial defects. In situ biomineralization using recombinant collagen as the unique biotemplate results in the formation of nano-hydroxyapatite with well-ordered mineralized recombinant collagen with fibrous morphology. The MRCSA scaffold finely mimics the organic-inorganic composition and the uniform porous nanostructures of natural bone, which exhibits excellent biocompatibility, adequate biodegradability, superior cellular activity, and exceptional osteogenic differentiation capability. Magnetic resonance imaging (MRI), Micro-computed tomography (micro-CT), and histological characterization of rat models of critical-size cranial defects have consistently demonstrated that the MRCSA scaffold has regenerated an abundance of new bones to refill the defect sites with much higher bone mineral density, bone volume/total volume as well as trabeculae. The novel biomimetic scaffold provides a remarkably improved remedy of critical-size cranial defects, suggesting very promising applications in orthopedics and plastics.

Synergistic effect of metformin and vitamin D3 on osteogenic differentiation of human adipose tissue-derived mesenchymal stem cells under high d-glucose conditions

IntroductionVitamin D3 plays a vital role in bone health, with low levels of vitamin D3 being related to skeletal fragility, fractures, and metabolic disorders such as diabetes. Metformin is known as an antihyperglycemic agent for regulating blood sugar. A correlation between diabetes mellitus and osteoporosis is attracting considerable interest, and research to find the prevention and treatment is gradually being studied. In this study, we investigated the effect of metformin and vitamin D3 on osteogenic differentiation of human adipose tissue-derived mesenchymal stem cells (AT-MSCs) under high d-glucose concentrations and optimized by combining vitamin D3 and metformin in the process. MethodsROS production of AT-MSCs under high d-glucose conditions was measured by DCFH-DA assay. The differentiated AT-MSCs were analyzed by Alizarin Red S staining and optical density measurement. The investigation involved the examination of osteogenic master genes' expressions using quantitative reverse transcription polymerase chain reaction (qRT-PCR) techniques. ResultsInterestingly, the results have shown that human AT-MSCs will exhibit high ROS accumulation and low osteogenic differentiation capabilities, indicated by low calcium deposition, as well as low expression of indicative genes such as ALP, Runx-2 under high d-glucose conditions. The combination of vitamin D3 and metformin remarkedly accelerated the osteogenic differentiation of AT-MSCs under high d-glucose concentrations more effectively than the administration of either agent. ConclusionsThis study partially explains an aspect of an in vitro model for pre-clinical drug screening for osteoporosis-related diabetic pathological mechanisms, which can be applied for further research on the prevention or treatment of osteoporosis in diabetic patients.

Biomimetic collagen composite matrix-hydroxyapatite scaffold induce bone regeneration in critical size cranial defects

Although biomimetic scaffolds have been constructed to repair critical-size bone defects, the creation of composite scaffolds that can mimic the anisotropy of natural bone remains a major challenge. Herein, we have for the first time developed a biomimetic collagen composite matrix-hydroxyapatite (CCMH) scaffold, which highly resembles both the composition and the anisotropy hierarchical structure of natural bone. The CCMH scaffold was created through unidirectional freeze-casting and in situ peristaltic mineralization, resulting in uniformly distributed nano-hydroxyapatite on the porous collagen composite matrix (CCM) scaffold. The CCMH scaffold finely mimics the composition and anisotropic channel-like morphology of native bone, which exhibits high biocompatibility, excellent cellular activity and extraordinary osteogenic differentiation capability. Magnetic resonance imaging (MRI), micro-computed tomography (micro-CT) and histological analysis of rat models demonstrated that the CCMH scaffold significantly enhanced new bone formation and accelerated bone regeneration. The innovative unidirectional freezing-in situ peristaltic mineralization approach offers a robust technique for building biomimetic three-dimensional porous scaffolds with excellent biocompatibility and osteoinductivity, which show significant promise for use in bone repair and regeneration.

Titanium-Dioxide-Nanoparticle-Embedded Polyelectrolyte Multilayer as an Osteoconductive and Antimicrobial Surface Coating

Bioactive surface coatings have retained the attention of researchers and physicians due to their versatility and range of applications in orthopedics, particularly in infection prevention. Antibacterial metal nanoparticles (mNPs) are a promising therapeutic, with vast application opportunities on orthopedic implants. The current research aimed to construct a polyelectrolyte multilayer on a highly porous titanium implant using alternating thin film coatings of chitosan and alginate via the layer-by-layer (LbL) self-assembly technique, along with the incorporation of silver nanoparticles (AgNPs) or titanium dioxide nanoparticles (TiO2NPs), for antibacterial and osteoconductive activity. These mNPs were characterized for their physicochemical properties using quartz crystal microgravimetry with a dissipation system, nanoparticle tracking analysis, scanning electron microscopy, and atomic force microscopy. Their cytotoxicity and osteogenic differentiation capabilities were assessed using AlamarBlue and alkaline phosphatase (ALP) activity assays, respectively. The antibiofilm efficacy of the mNPs was tested against Staphylococcus aureus. The LbL polyelectrolyte coating was successfully applied to the porous titanium substrate. A dose-dependent relationship between nanoparticle concentration and ALP as well as antibacterial effects was observed. TiO2NP samples were also less cytotoxic than their AgNP counterparts, although similarly antimicrobial. Together, these data serve as a proof-of-concept for a novel coating approach for orthopedic implants with antimicrobial and osteoconductive properties.