Osteogenic Capacity Research Articles

Synergistic Osteogenic and Antiapoptotic Framework Nucleic Acid Complexes Prevent Diabetic Osteoporosis

AbstractDiabetes mellitus (DM) is characterized by elevated blood glucose and advanced glycation end product (AGEs) levels. Increased AGEs in bone tissue inhibit osteogenic differentiation by bone marrow mesenchymal stem cells (BMSCs), leading to bone loss and osteoporosis in diabetic patients. Enhancing the osteogenic differentiation capacity of BMSCs in the presence of abundant AGEs can improve bone health and prevent osteoporosis in DM patients. The flavonoid, Quercetin, has anti‐inflammatory, antibacterial, and antitumor properties; however, it is insoluble in water and thus not easily absorbed by the body. Nanodrug delivery systems such as tetrahedral framework nucleic acids (tFNAs) exhibit excellent biocompatibility, efficient cell uptake, and drug piggybacking. In the present study, tFNAs with quercetin is complexed to form a novel nanodrug (tFNAs/Que) that combined the features of both components. tFNAs/Que promote osteogenic differentiation by BMSCs in an in vitro AGEs‐rich environment, maintain bone mass, and prevent diabetic osteoporosis in DM mice in vivo. The mechanism of tFNAs/Que against AGEs may be related to the JNK signaling pathway. In conclusion, it is shown that tFNAs/Que has a dual regulatory role by promoting osteogenic differentiation and inhibiting apoptosis. Such a feature is promising for the prevention and treatment of diabetic osteoporosis.

Osteopontin Rejuvenates Senescent Adipose-Derived Stem Cells and Restores their Bone Tissue Regenerative Function

The regenerative function of stem cells is compromised when the proportion of senescent stem cells increases with ageing advance. Therefore, combating stem cell senescence is of great importance for stem cell-based tissue engineering in the elderly, but remains largely unexplored. Osteopontin (OPN), a glycosylated phosphoprotein, is one of the key extracellular matrix molecules in bone tissue. OPN activates various signalling pathways and modulates cellular activities, including cell senescence. However, the role of OPN in stem cell senescence remains largely unknown. This study aims to investigate if OPN modulates cell senescence and bone regenerative function in human adipose-derived mesenchymal stem cells (ASCs), and to determine the underlying mechanisms. We first developed a senescent ASC model using serial passaging until passage 10 (P10), in which senescent cells were characterised by reduced proliferation and osteogenic differentiation capacity compared to P4 ASCs. The conditioned medium from P10 ASCs exhibited a diminished trophic effect on human osteoblasts (HOBs), compared to that from P4 ASCs. P10 ASCs on OPN-coated surface showed rejuvenated phenotype and enhanced osteogenic differentiation. The conditioned medium from P10 ASCs on OPN-coating improved trophic effects on HOBs. OPN regulated the morphology of senescent ASCs, transforming them from a more rounded and flattened cell shape to an elongated shape with a smaller area. These findings demonstrated the effects of OPN in restoring senescent ASCs functions, possibly through a mechanism that involves the modulation of cell morphology, indicating that OPN might hold a great potential for rejuvenating senescent stem cells and could potentially open a new venue for regenerating bone tissue in age-related diseases.Graphical

Leptin receptor (+) stromal cells respond to periodontitis and attenuate alveolar bone repair via CCRL2-mediated Wnt inhibition.

The impaired bone healing in tooth extraction sockets due to periodontitis presents a major obstacle to restoring oral health. The mechanisms regulating the osteogenic capacity of jawbone-derived stromal cells in the periodontitis microenvironment remain elusive. Leptin receptor (LepR) expressing stromal cells, which largely overlap with Cxcl12-abundant reticular (CAR) cells in bone tissue, rapidly proliferate and differentiate into bone-forming cells during extraction socket healing to support alveolar bone repair. In this study, we identify that CCRL2 is significantly expressed and inhibits osteogenesis in LepR+/CAR cells of alveolar bones with periodontitis. The Ccrl2-KO mice exhibit significant improvements in bone healing in extraction sockets with periodontitis. Specifically, the binding of CCRL2 to SFRP1 on the surface of LepR+/CAR cells can amplify the suppressive effect of SFRP1 on Wnt signaling under inflammation, thus hindering the osteogenic differentiation of LepR+/CAR cells and resulting in poor bone healing in extraction sockets with periodontitis. Together, we clarify that the CCRL2 receptor of LepR+/CAR cells can respond to periodontitis and crosstalk with Wnt signaling to deteriorate extraction socket healing.

Fibroblast growth factor 7 protects osteoblasts against oxidative damage through targeting mitochondria.

The pathophysiology of osteoporosis is significantly influenced by the impaired functioning of osteoblasts, which is particularly caused by oxidative stress. Nevertheless, the underlying mechanisms responsible for this phenomenon are still not well understood. The objective of this study was to elucidate the impact of fibroblast growth factor 7 (FGF7) on the behavior of osteoblasts under conditions of oxidative stress. The osteoblast-like MC3T3 cells were pretreated with recombinant FGF7 in the presence of oxidative stress induced by hydrogen peroxide (H2 O2 ). We first provided the evidence that the endogenous FGF7 was significantly increased in osteoblasts in response to the increased H2 O2 levels. Recombined FGF7 demonstrated a remarkable capacity to resist the detrimental effects of H2 O2 -induced oxidative stress, including the increase in cell apoptosis, decrease in osteoblast viability, and impairment in osteogenic differentiation capacity, on osteoblasts. Furthermore, we extensively explored the mechanism underlying these protective effects and discovered a remarkable modulation of reactive oxygen species (ROS) homeostasis in H2 O2 -treated cells following the pronounced expression of FGF7, which significantly differed from the control group. Additionally, we observed that FGF7 exerted partial preservation on both the morphology and function of mitochondria when exposed to oxidative stress conditions. Furthermore, FGF7 exhibited the ability to enhance the activation of the p38/MAPK signaling pathway while concurrently suppressing the JNK/MAPK signaling pathway in response to oxidative stress. These results underscore the promising role and underlying mechanisms of FGF7 in preserving osteoblast homeostasis in the face of oxidative stress.

Simultaneous Regulation of the Mechanical/Osteogenic Capacity of Brushite Calcium Phosphate Cement by Incorporating with Poly(ethylene glycol) Dicarboxylic Acid.

Brushite calcium phosphate cement (brushite CPC) is a prospective bone repair material due to its ideal resorption rates in vivo. However, the undesirable mechanical property and bioactivity limited its availability in clinic application. To address this issue, incorporating polymeric additives has emerged as a viable solution. In this study, poly(ethylene glycol) dicarboxylic acid, PEG(COOH), was synthesized and employed as the polymeric additive. The setting behavior, anti-washout ability, mechanical property, degradation rate, and osteogenic capacity of brushite CPC were regulated by incorporating PEG(COOH). The incorporation of PEG(COOH) with carboxylic acid groups demonstrated a positive effect on both mechanical properties and osteogenic activity in bone repair. This study offers valuable insights and suggests a promising strategy for the development of materials in bone tissue engineering.

3D printed high-precision porous scaffolds prepared by fused deposition modeling induce macrophage polarization to promote bone regeneration

Macrophage-mediated bone immune responses significantly influence the repair of bone defects when utilizing tissue-engineered scaffolds. Notably, the scaffolds’ physical structure critically impacts macrophage polarization. The optimal pore size for facilitating bone repair remains a topic of debate due to the imprecision of traditional methods in controlling scaffold pore dimensions and spatial architecture. In this investigation, we utilized fused deposition modeling (FDM) technology to fabricate high-precision porous polycaprolactone (PCL) scaffolds, aiming to elucidate the impact of pore size on macrophage polarization. We assessed the scaffolds’ mechanical attributes and biocompatibility. Real-time quantitative reverse transcription polymerase chain reaction was used to detect the expression levels of macrophage-related genes, and enzyme linked immunosorbent assay for cytokine secretion levels. In vitro osteogenic capacity was determined through alkaline phosphatase and alizarin red staining. Our findings indicated that macroporous scaffolds enhanced macrophage adhesion and drove their differentiation towards the M2 phenotype. This led to the increased production of anti-inflammatory factors and a reduction in pro-inflammatory agents, highlighting the scaffolds’ immunomodulatory capabilities. Moreover, conditioned media from macrophages cultured on these macroporous scaffolds bolstered the osteogenic differentiation of bone marrow mesenchymal stem cells, exhibiting superior osteogenic differentiation potential. Consequently, FDM-fabricated PCL scaffolds, with precision-controlled pore sizes, present promising prospects as superior materials for bone tissue engineering, leveraging the regulation of macrophage polarization.

CoCl2-Induced hypoxia promotes hPDLSCs osteogenic differentiation through AKT/mTOR/4EBP-1/HIF-1α signaling and facilitates the repair of alveolar bone defects.

Bone defects are characterized by a hypoxic environment, which affects bone tissue repair. However, the role of hypoxia in the repair of alveolar bone defects remains unclear. Human periodontal ligament stem cells (hPDLSCs) are high-quality seed cells for repairing alveolar bone defects, whose behavior changes under hypoxia. However, their mechanism of action is not known and needs to be elucidated. We hypothesized that hypoxia might be beneficial to alveolar bone defect repair and the osteogenic differentiation of hPDLSCs. To test this hypothesis, cobalt chloride (CoCl2) was used to create a hypoxic environment, both in vitro and in vivo. In vitro study, the best osteogenic effect was observed after 48 h of hypoxia in hPDLSCs, and the AKT/mammalian target of rapamycin/eukaryotic translation initiation factor 4e-binding protein 1 (AKT/mTOR/4EBP-1) signaling pathway was significantly upregulated. Inhibition of the AKT/mTOR/4EBP-1 signaling pathway decreased the osteogenic ability of hPDLSCs under hypoxia and hypoxia-inducible factor 1 alpha (HIF-1α) expression. The inhibition of HIF-1α also decreased the osteogenic capacity of hPDLSCs under hypoxia without significantly affecting the level of phosphorylation of AKT/mTOR/4EBP-1. In vitro study, Micro-CT and tissue staining results show better bone regeneration in hypoxic group than control group. These results suggested that hypoxia promoted alveolar bone defect repair and osteogenic differentiation of hPDLSCs, probably through AKT/mTOR/4EBP-1/HIF-1α signaling. These findings provided important insights into the regulatory mechanism of hypoxia in hPDLSCs and elucidated the effect of hypoxia on the healing of alveolar bone defects. This study highlighted the importance of physiological oxygen conditions for tissue engineering.

The Dual Angiogenesis Effects via Nrf2/HO-1 Signaling Pathway of Melatonin Nanocomposite Scaffold on Promoting Diabetic Bone Defect Repair.

Given the escalating prevalence of diabetes, the demand for specific bone graft materials is increasing, owing to the greater tendency towards bone defects and more difficult defect repair resulting from diabetic bone disease (DBD). Melatonin (MT), which is known for its potent antioxidant properties, has been shown to stimulate both osteogenesis and angiogenesis. MT was formulated into MT@PLGA nanoparticles (NPs), mixed with sodium alginate (SA) hydrogel, and contained within a 3D printing polycaprolactone/β-Tricalcium phosphate (PCL/β-TCP) scaffold. The osteogenic capacity of the MT nanocomposite scaffold under diabetic conditions was demonstrated via in vitro and in vivo studies and the underlying mechanisms were investigated. Physicochemical characterization experiments confirmed the successful fabrication of the MT nanocomposite scaffold, which can achieve long-lasting sustained release of MT. The in vitro and in vivo studies demonstrated that the MT nanocomposite scaffold exhibited enhanced osteogenic capacity, which was elucidated by the dual angiogenesis effects activated through the NF-E2-related factor 2/Heme oxygenase 1 (Nrf2/HO-1) signaling pathway, including the enhancement of antioxidant enzyme activity to reduce the oxidative stress damage of vascular endothelial cells (VECs) and directly stimulating vascular endothelial growth factor (VEGF) production, which reversed the angiogenesis-osteogenesis uncoupling and promoted osteogenesis under diabetic conditions. This study demonstrated the research prospective and clinical implications of the MT nanocomposite scaffold as a novel bone graft for treating bone defect and enhancing bone fusion in diabetic individuals.

Nr4a1 enhances Wnt4 transcription to promote mesenchymal stem cell osteogenesis and alleviates inflammation-inhibited bone regeneration

Intense inflammatory response impairs bone marrow mesenchymal stem cell (BMSC)-mediated bone regeneration, with TGF-β1 being the most highly expressed cytokine. However, how to find effective and safe means to improve bone formation impaired by excessive TGF-β1 remains unclear. In this study, we found that the expression of orphan nuclear receptor Nr4a1, an endogenous repressor of TGF-β1, was suppressed directly by TGF-β1-induced Smad3 and indirectly by Hdac4, respectively. Importantly, Nr4a1 overexpression promoted BMSC osteogenesis and reversed TGF-β1-mediated osteogenic inhibition and pro-fibrotic effects. Transcriptomic and histologic analyses confirmed that upregulation of Nr4a1 increased the transcription of Wnt family member 4 (Wnt4) and activated Wnt pathway. Mechanistically, Nr4a1 bound to the promoter of Wnt4 and regulated its expression, thereby enhancing the osteogenic capacity of BMSCs. Moreover, treatment with Nr4a1 gene therapy or Nr4a1 agonist Csn-B could promote ectopic bone formation, defect repair, and fracture healing. Finally, we demonstrated the correlation of NR4A1 with osteogenesis and the activation of the WNT4/β-catenin pathway in human BMSCs and fracture samples. Taken together, these findings uncover the critical role of Nr4a1 in bone formation and alleviation of inflammation-induced bone regeneration disorders, and suggest that Nr4a1 has the potential to be a therapeutic target for accelerating bone healing.

Advanced glycation end products promote meniscal calcification by activating the mTOR-ATF4 positive feedback loop

The meniscus is vital for maintaining knee homeostasis and function. Meniscal calcification is one of the earliest radiological indicators of knee osteoarthritis (KOA), and meniscal calcification is associated with alterations in biomechanical properties. Meniscal calcification originates from a biochemical process similar to vascular calcification. Advanced glycation end products (AGEs) and their receptors (RAGEs) reportedly play critical roles in vascular calcification. Herein, we investigated whether targeting AGE-RAGE is a potential treatment for meniscal calcification. In our study, we demonstrated that AGE-RAGE promotes the osteogenesis of meniscal cells and exacerbates meniscal calcification. Mechanistically, AGE-RAGE activates mTOR and simultaneously promotes ATF4 accumulation, thereby facilitating the ATF4-mTOR positive feedback loop that enhances the osteogenic capacity of meniscal cells. In this regard, mTOR inhibits ATF4 degradation by reducing its ubiquitination, while ATF4 activates mTOR by increasing arginine uptake. Our findings substantiate the unique role of AGE-RAGE in the meniscus and reveal the role of the ATF4-mTOR positive feedback loop during the osteogenesis of meniscal cells; these results provide potential therapeutic targets for KOA.

Empagliflozin Ameliorates the Impaired Osteogenic Differentiation Ability of Adipose-Derived Stem Cells in Diabetic Osteoporosis by Activating Autophagy.

Adipose-derived stem cells (ASCs) from diabetic osteoporosis (DOP) mice showed impaired osteogenic differentiation capacity. Recent studies have shown that in addition to antidiabetic drugs, sodium-glucose co-transporter inhibitor-2 (SGLT-2), empagliflozin, can play multipotent roles through various mechanisms of action. In this study, we aimed to investigate the effects and underlying mechanisms of empagliflozin on osteogenic differentiation of ASCs in DOP mice. Our results showed that osteogenic differentiation potential and autophagy activity weakened in DOP-ASCs when compared to controls. However, empagliflozin enhanced autophagy flux by promoting the formation of autophagosomes and acidification of autophagic lysosomes, resulting in an increase in LC3-II expression and a decrease in SQSTM1 expression. Furthermore, empagliflozin contributed to the reversal of osteogenesis inhibition in DOP-ASCs induced by a diabetic microenvironment. When 3-methyladenine was used to block autophagy activity, empagliflozin could not exert its protective effect on DOP-ASCs. Nonetheless, this study demonstrated that the advent of cellular autophagy attributed to the administration of empagliflozin could ameliorate the impaired osteogenic differentiation potential of ASCs in DOP mice. This finding might be conducive to the application of ASCs transplantation for promoting bone fracture healing and bone regeneration in patients with DOP.

Fabrication and properties of PLA/β-TCP scaffolds using liquid crystal display (LCD) photocuring 3D printing for bone tissue engineering.

Introduction: Bone defects remain a thorny challenge that clinicians have to face. At present, scaffolds prepared by 3D printing are increasingly used in the field of bone tissue repair. Polylactic acid (PLA) has good thermoplasticity, processability, biocompatibility, and biodegradability, but the PLA is brittle and has poor osteogenic performance. Beta-tricalcium phosphate (β-TCP) has good mechanical properties and osteogenic induction properties, which can make up for the drawbacks of PLA. Methods: In this study, photocurable biodegradable polylactic acid (bio-PLA) was utilized as the raw material to prepare PLA/β-TCP slurries with varying β-TCP contents (β-TCP dosage at 0%, 10%, 20%, 30%, 35% of the PLA dosage, respectively). The PLA/β-TCP scaffolds were fabricated using liquid crystal display (LCD) light-curing 3D printing technology. The characterization of the scaffolds was assessed, and the biological activity of the scaffold with the optimal compressive strength was evaluated. The biocompatibility of the scaffold was assessed through CCK-8 assays, hemocompatibility assay and live-dead staining experiments. The osteogenic differentiation capacity of the scaffold on MC3T3-E1 cells was evaluated through alizarin red staining, alkaline phosphatase (ALP) detection, immunofluorescence experiments, and RT-qPCR assays. Results: The prepared scaffold possesses a three-dimensional network structure, and with an increase in the quantity of β-TCP, more β-TCP particles adhere to the scaffold surface. The compressive strength of PLA/β-TCP scaffolds exhibits a trend of initial increase followed by decrease with an increasing amount of β-TCP, reaching a maximum value of 52.1MPa at a 10% β-TCP content. Degradation rate curve results indicate that with the passage of time, the degradation rate of the scaffold gradually increases, and the pH of the scaffold during degradation shows an alkaline tendency. Additionally, Live/dead staining and blood compatibility experiments suggest that the prepared PLA/β-TCP scaffold demonstrates excellent biocompatibility. CCK-8 experiments indicate that the PLA/β-TCP group promotes cell proliferation, and the prepared PLA/β-TCP scaffold exhibits a significant ability to enhance the osteogenic differentiation of MC3T3-E1 cells in vitro. Discussion: 3D printed LCD photocuring PLA/β-TCP scaffolds could improve surface bioactivity and lead to better osteogenesis, which may provide a unique strategy for developing bioactive implants in orthopedic applications.

Porcine Mandibular Bone Marrow-Derived Mesenchymal Stem Cell (BMSC)-Derived Extracellular Vesicles Can Promote the Osteogenic Differentiation Capacity of Porcine Tibial-Derived BMSCs.

Existing research suggests that bone marrow-derived mesenchymal stem cells (BMSCs) may promote endogenous bone repair. This may be through the secretion of factors that stimulate repair processes or directly through differentiation into osteoblast-progenitor cells. However, the osteogenic potential of BMSCs varies among different tissue sources (e.g., mandibular versus long BMSCs). The main aim of this study was to investigate the difference in osteogenic differentiation capacity between mandibular BMSCs (mBMSCs) and tibial BMSCs (tBMSCs). Bioinformatics analysis of the GSE81430 dataset taken from the Gene Expression Omnibus (GEO) database was performed using GEO2R. BMSCs were isolated from mandibular and tibial bone marrow tissue samples. Healthy pigs (n = 3) (registered at the State Office for Nature, Environment, and Consumer Protection, North Rhine-Westphalia (LANUV) 81-02.04.2020.A215) were used for this purpose. Cell morphology and osteogenic differentiation were evaluated in mBMSCs and tBMSCs. The expression levels of toll-like receptor 4 (TLR4) and nuclear transcription factor κB (NF-κB) were analyzed using quantitative polymerase chain reaction (qPCR) and Western blot (WB), respectively. In addition, mBMSC-derived extracellular vesicles (mBMSC-EVs) were gained and used as osteogenic stimuli for tBMSCs. Cell morphology and osteogenic differentiation capacity were assessed after mBMSC-EV stimulation. Bioinformatic analysis indicated that the difference in the activation of the TLR4/NF-κB pathway was more pronounced compared to all other examined genes. Specifically, this demonstrated significant downregulation, whereas only 5-7 upregulated genes displayed significant variances. The mBMSC group showed stronger osteogenic differentiation capacity compared to the tBMSC group, confirmed via ALP, ARS, and von Kossa staining. Furthermore, qPCR and WB analysis revealed a significant decrease in the expression of the TLR4/NF-κB pathway in the mBMSC group compared to the tBMSC group (TLR4 fold changes: mBMSCs vs. tBMSCs p < 0.05; NF-κB fold changes: mBMSCs vs. tBMSCs p < 0.05). The osteogenic differentiation capacity was enhanced, and qPCR and WB analysis revealed a significant decrease in the expression of TLR4 and NF-κB in the tBMSC group with mBMSC-EVs added compared to tBMSCs alone (TLR4 fold changes: p < 0.05; NF-κB fold changes: p < 0.05). Our results indicate that mBMSC-EVs can promote the osteogenic differentiation of tBMSCs in vitro. The results also provide insights into the osteogenic mechanism of mBMSCs via TLR4/NF-κB signaling pathway activation. This discovery promises a fresh perspective on the treatment of bone fractures or malunions, potentially offering a novel therapeutic method.

Nanosized Silk-Magnesium Complexes for Promotion of Angiogenic and Osteogenic Activities.

Injectable hydrogels with osteogenic and angiogenetic properties are of interest in bone tissue engineering. Since the bioactivity of ions is concentration-dependent, nanosized silk-magnesium (Mg) complexes were previously developed and assembled into hydrogels with angiogenic capabilities but failed to control both osteogenic and angiogenetic activities effectively. Here, nanosized silk particles with different sizes were obtained by using ultrasonic treatment to control silk-Mg coordination and particle formation, resulting in silk-Mg hydrogels with different types of bioactivity. Fourier transform infrared and X-ray diffraction results revealed that different coordination intensities were present in the different complexes as a basis for the differences in activities. Slow Mg ion release was controlled by these nanosized silk-Mg complexes through degradation. With the same amount of Mg ions, the different silk-Mg complexes exhibited different angiogenic and osteogenic capacities. Complexes with both angiogenic and osteogenic capacities were developed by optimizing the sizes of the silk particles, resulting in faster and improved quality of bone formed in vivo than complexes with the same composition of silk and Mg but only angiogenic or osteogenic capacities. The biological selectivity of silk-Mg complexes should facilitate applications in tissue regeneration.

Inhibition of PTEN promotes osteointegration of titanium implants in type 2 diabetes by enhancing anti-inflammation and osteogenic capacity of adipose-derived stem cells.

Background: The low osteogenic differentiation potential and attenuated anti-inflammatory effect of adipose-derived stem cells (ADSCs) from animals with type 2 diabetes mellitus (T2DM) limits osseointegration of the implant. However, the underlying mechanisms are not fully understood. Methods: Western blotting and qRT-PCR analyses were performed to investigate the effects of PTEN on the osteogenic capacity of ADSCs of T2DM rats (TADSCs). We conducted animal experiments in T2DM-Sprague Dawley (SD) rats to evaluate the osteogenic capacity of modified TADSC sheets in vivo. New bone formation was assessed by micro-CT and histological analyses. Results: In this study, adipose-derived stem cells of T2DM rats exhibited an impaired osteogenic capacity. RNA-seq analysis showed that PTEN mRNA expression was upregulated in TADSCs, which attenuated the osteogenic capacity of TADSCs by inhibiting the AKT/mTOR/HIF-1α signaling pathway. miR-140-3p, which inhibits PTEN, was suppressed in TADSCs. Overexpression or inhibition of PTEN could correspondingly reduce or enhance the osteogenic ability of TADSCs by regulating the AKT/mTOR/HIF-1α signaling pathway. TADSCs transfected with PTEN siRNA resulted in higher and lower expressions of genes encoded in M2 macrophages (Arg1) and M1 macrophages (iNOS), respectively. In the T2DM rat model, PTEN inhibition in TADSC sheets promoted macrophage polarization toward the M2 phenotype, attenuated inflammation, and enhanced osseointegration around implants. Conclusion: Upregulation of PTEN, which was partially due to the inhibition of miR-140-3p, is important for the attenuated osteogenesis by TADSCs owing to the inhibition of the AKT/mTOR/HIF-1α signaling pathway. Inhibition of PTEN significantly improves the anti-inflammatory effect and osteogenic capacity of TADSCs, thus promoting peri-implant bone formation in T2DM rats. Our findings offer a potential therapeutic approach for modifying stem cells derived from patients with T2DM to enhance osseointegration.

Engineering a Hybrid Ti6Al4V-Based System for Responsive and Consistent Osteogenesis.

As the aging population increases worldwide, the incidence of musculoskeletal diseases and the need for orthopedic implants also arise. One of the most desirable goals in orthopedic reconstructive therapies is de novo bone formation. Yet, reproducible, long-lasting, and cost-effective strategies for implants that strongly induce osteogenesis are still in need. Nanoengineered titanium substrates (and their alloys) are among the most used materials in orthopedic implants. Although having high biocompatibility, titanium alloys hold a low bioactivity profile. The osteogenic capacity and osseointegration of Ti-based implantable systems are limited, as they critically depend on the body-substrate interactions defined by blood proteins adsorbed into implant surfaces that ultimately lead to the recruitment, proliferation, and differentiation of mesenchymal stem cells (MSCs) to comply bone formation and regeneration. In this work, a hybrid Ti6Al4V system combining micro- and nanoscale modifications induced by hydrothermal treatment followed by functionalization with a bioactive compound (fibronectin derived from human plasma) is proposed, aiming for bioactivity improvement. An evaluation of the biological activity and cellular responses in vitro with respect to bone regeneration indicated that the integration of morphological and chemical modifications into Ti6Al4V surfaces induces the osteogenic differentiation of MSCs to improve bone regeneration by an enhancement of mineral matrix formation that accelerates the osseointegration process. Overall, this hybrid system has numerous competitive advantages over more complex treatments, including reproducibility, low production cost, and potential for improved long-term maintenance of the implant.

Injectable ultrasound-powered bone-adhesive nanocomposite hydrogel for electrically accelerated irregular bone defect healing

The treatment of critical-size bone defects with irregular shapes remains a major challenge in the field of orthopedics. Bone implants with adaptability to complex morphological bone defects, bone-adhesive properties, and potent osteogenic capacity are necessary. Here, a shape-adaptive, highly bone-adhesive, and ultrasound-powered injectable nanocomposite hydrogel is developed via dynamic covalent crosslinking of amine-modified piezoelectric nanoparticles and biopolymer hydrogel networks for electrically accelerated bone healing. Depending on the inorganic-organic interaction between the amino-modified piezoelectric nanoparticles and the bio-adhesive hydrogel network, the bone adhesive strength of the prepared hydrogel exhibited an approximately 3-fold increase. In response to ultrasound radiation, the nanocomposite hydrogel could generate a controllable electrical output (-41.16 to 61.82 mV) to enhance the osteogenic effect in vitro and in vivo significantly. Rat critical-size calvarial defect repair validates accelerated bone healing. In addition, bioinformatics analysis reveals that the ultrasound-responsive nanocomposite hydrogel enhanced the osteogenic differentiation of bone mesenchymal stem cells by increasing calcium ion influx and up-regulating the PI3K/AKT and MEK/ERK signaling pathways. Overall, the present work reveals a novel wireless ultrasound-powered bone-adhesive nanocomposite hydrogel that broadens the therapeutic horizons for irregular bone defects.

Mesoporous bioactive glass scaffolds for the delivery of bone marrow stem cell-derived osteoinductive extracellular vesicles lncRNA promote senescent bone defect repair by targeting the miR-1843a-5p/Mob3a/YAP axis

Bone repair in elderly patients poses a huge challenge due to the age-related progressive decline in regenerative abilities attributed to the senescence of bone marrow stem cells (BMSCs). Bioactive scaffolds have been applied in bone regeneration due to their various biological functions. In this study, we aimed to fabricate functionalized bioactive scaffolds through loading osteoinductive extracellular vesicles (OI-EVs) based on mesoporous bioactive glass (MBG) scaffolds (1010 particles/scaffold) and to investigate its effects on osteogenesis and senescence of BMSCs. The results suggested that OI-EVs upregulate the proliferative and osteogenic capacities of senescent BMSCs. More importantly, The results showed that loading OI-EVs into MBG scaffolds achieved better bone regeneration. Furthermore, OI-EVs and BMSCs RNAs bioinformatics analysis indicated that OI-EVs play roles through transporting pivotal lncRNA acting as a “sponge” to compete with Mob3a for miR-1843a-5p to promote YAP dephosphorylation and nuclear translocation, ultimately resulting in elevated proliferation and osteogenic differentiation and reduced senescence-related phenotypes. Collectively, these results suggested that the OI-EVs lncRNA ceRNA regulatory networks might be the key point for senescent osteogenesis. More importantly, the study indicated the feasibility of loading OI-EVs into scaffolds and provided novel insights into biomaterial design for facilitating bone regeneration in the treatment of senescent bone defects. Statement of significanceConstructing OI-EVs/MBG delivering system and verification of its bone regeneration enhancement in senescent defect repair.Aging bone repair poses a huge challenge due to the age-related progressive degenerative decline in regenerative abilities attributed to the senescence of BMSCs. OI-EVs/MBG delivering system were expected as promising treatment for senescent bone repair, which could provide an effective strategy for bone regeneration in elderly patients.Clarification of potential OI-EVs lncRNA ceRNA regulatory mechanism in senescent bone regenerationOI-EVs play important roles through transferring lncRNA-ENSRNOG00000056625 sponging miR-1843a-5p that targeted Mob3a to activate YAP translocation into nucleus, ultimately alleviate senescence, promote proliferation and osteogenic differentiation in O-BMSCs, which provides theoretical basis for EVs-mediated therapy in future clinical works.

Eggshell membrane as a regenerative material in alveolar bone grafting in combination with advanced platelet rich fibrin.

The eggshell and the eggshell membrane (ESM) are significant by-products of the poultry industry and are being utilized for various valuable purposes in health care, like soft tissue healing and pain alleviation. The aim and objective of our study are to assess the effect of the eggshell membrane on alveolar bone regeneration after tooth extraction. A total of 40 extraction sockets (bilateral) among 20 patients were assessed clinically for healing, and radiographic parameters of bone density and socket volume were assessed on CBCT at baseline, 3 months, and 6 months. Advanced platelet-rich fibrin was created from 5 ml of autologous blood from the patient and centrifuged for 15 minutes at 1500 RPM/168 RCF. The commercially available powdered form of egg shell membrane was used in the study. Based on the randomized allotment (coin-flip), A-PRF alone or A-PRF mixed with eggshell membrane was placed inside the extraction socket and was stabilized using 3-0 silk sutures. It was ob-served that wound healing was uneventful in all 20 patients. No evidence of dry sockets or allergic reactions was noted in any patient. Statistical analysis was done using the un-paired t-test and Mann-Whitney U test with SPSS version 20.0. P<0.05 was considered significant. On comparison of the mean bone density at baseline, 3 months, and 6 months, the socket density in the eggshell with the PRF group was higher compared to the control group. To conclude, eggshell membrane has good regenerative properties and excellent osteogenic capacity; therefore, it could be a useful graft due to its low cost, abundant availability, and simple application.

Electron beam radiation constructed and improved bone repairing performance based on hierarchical thermoplastic polyurethane/graphene oxide/hydroxyapatite hot melt adhesive with high flow ductility

AbstractThe aging population increased the demand for the development and utilization of bone filling materials. In this study, hydroxyapatite (HAP) and graphene oxide (GO) were introduced into thermoplastic polyurethane (TPU) by melt mixing and electron beam radiation to obtain the new hot melt adhesive (TPU/HAP/GO). The structures and morphologies of the TPU/HAP/GO were analyzed using FTIR, XRD, SEM, BET, DSC. The mechanical properties of the TPU/HAP/GO were evaluated using a universal testing machine. TPU/HAP/GO was demonstrated to have good bacterial inhibition by the zone of inhibition test and plate method. The good biocompatibility of the hot melt adhesive was demonstrated using the MTT method and the Hoechst 33342/PI double staining method. The osteogenic differentiation of mouse osteoblasts (MC3T3‐E1) treated with TPU/HAP/GO was detected by alkaline phosphatase (ALP) staining. ALP staining showed that the hot melt adhesive promoted the differentiation of MC3T3‐E1 cells into osteoblasts. This hot melt adhesive had great application potential in bone tissue engineering.Highlights Green electron beam radiation method for synthesizing hot melt adhesives. Enhanced mechanical properties of composites by incorporation of graphene oxide. Improvement of antimicrobial and osteogenic capacities for polyurethane.