Defect Model Research Articles

Enhanced osteogenic potential of iPSC-derived mesenchymal progenitor cells following genome editing of GWAS variants in the RUNX1 gene

Recent genome-wide association studies (GWAS) identified 518 significant loci associated with bone mineral density (BMD), including variants at the RUNX1 locus (rs13046645, rs2834676, and rs2834694). However, their regulatory impact on RUNX1 expression and bone formation remained unclear. This study utilized human induced pluripotent stem cells (iPSCs) differentiated into osteoblasts to investigate these variants’ regulatory roles. CRISPR/Cas9 was employed to generate mutant (Δ) iPSC lines lacking these loci at the RUNX1 locus. Deletion lines (Δ1 and Δ2) were created in iPSCs to assess the effects of removing regions containing these loci. Deletion lines exhibited enhanced osteogenic potential, with increased expression of osteogenic marker genes and Alizarin Red staining. Circularized chromosome conformation capture (4C-Seq) was utilized to analyze interactions between BMD-associated loci and the RUNX1 promoter during osteogenesis. Analysis revealed altered chromatin interactions with multiple gene promoters including RUNX1 isoform, as well as SETD4, a histone methyltransferase, indicating their regulatory influence. Interestingly, both deletion lines notably stimulated the expression of the long isoform of RUNX1, with more modest effects on the shorter isoform. Consistent upregulation of SETD4 and other predicted targets within the Δ2 deletion suggested its removal removed a regulatory hub constraining expression of multiple genes at this locus. In vivo experiments using a bone defect model in mice demonstrated increased bone regeneration with homozygous deletion of the Δ2 region. These findings indicate that BMD-associated variants within the RUNX1 locus regulate multiple effector genes involved in osteoblast commitment, providing valuable insights into genetic regulation of bone density and potential therapeutic targets.

Oxidative stress and apoptosis of the spinal cord in a rat model of retinoic acid-induced neural tube defects.

Neural tube defects (NTDs) are severe congenital anomalies that significantly impact the central nervous system, arising from the neural tube's failure to close during early embryogenesis. In this study, we investigated NTDs and associated pathophysiological mechanisms in foetal rats following exposure to all-trans retinoic acid (atRA). Out of 168 embryos from 15 pregnant rats in the experimental group, 78% displayed NTDs with notable spinal deformities, primarily in the lumbar-sacral region, similar to human cases. Body weight and crown-rump length (CRL) measurements indicated significant growth impairment in the NTD group compared to controls, while the atRA-treated group without NTDs showed no notable differences in growth. Immunohistochemistry (IHC) results demonstrated decreased NeuN and PCNA expression in the NTD group's spinal cord. Oxidative stress markers showed markedly reduced superoxide dismutase (SOD) and glutathione peroxidase (GSH-px) activity, alongside increased malondialdehyde (MDA) levels in the NTD group, indicating heightened oxidative stress. Analysis of apoptosis-related proteins revealed elevated Bax and caspase-3 levels, reduced Bcl-2 and lower poly (ADP-ribose) polymerase (PARP) in the NTD group, suggesting a pronounced shift towards proapoptotic pathways, potentially contributing to NTD progression. Our findings indicate that oxidative stress and apoptosis play significant roles in the development of NTDs. Future investigations should aim to pinpoint critical regulatory genes or proteins that might be targeted for therapeutic interventions to alleviate oxidative stress and apoptosis in NTD development.

Biodegradable Janus sonozyme with continuous reactive oxygen species regulation for treating infected critical-sized bone defects

Critical-sized bone defects are usually accompanied by bacterial infection leading to inflammation and bone nonunion. However, existing biodegradable materials lack long-term therapeutical effect because of their gradual degradation. Here, a degradable material with continuous ROS modulation is proposed, defined as a sonozyme due to its functions as a sonosensitizer and a nanoenzyme. Before degradation, the sonozyme can exert an effective sonodynamic antimicrobial effect through the dual active sites of MnN4 and Cu2O8. Furthermore, it can promote anti-inflammation by superoxide dismutase- and catalase-like activities. Following degradation, quercetin-metal chelation exhibits a sustaining antioxidant effect through ligand-metal charge transfer, while the released ions and quercetin also have great self-antimicrobial, osteogenic, and angiogenic effects. A rat model of infected cranial defects demonstrates the sonozyme can rapidly eliminate bacteria and promote bone regeneration. This work presents a promising approach to engineer biodegradable materials with long-time effects for infectious bone defects.

Exosomes derived from minor salivary gland mesenchymal stem cells: a promising novel exosome exhibiting pro-angiogenic and wound healing effects similar to those of adipose-derived stem cell exosomes

BackgroundsMinor salivary gland mesenchymal stem cells (MSGMSCs) can be easily extracted and have a broad range of sources. Applying exosomes to wounds is a highly promising method for promoting wound healing. Exosomes derived from different stem cell types have been proven to enhance wound healing, with adipose-derived stem cell (ADSC)-derived exosomes being the most extensively researched. Considering that MSGMSCs have advantages such as easier extraction compared to ADSCs, MSGMSCs should also be a very promising type of stem cell in exosome therapy. However, whether MSGMSC-derived exosomes (MSGMSC-exos) can promote wound healing and how they compare to ADSC-derived exosomes (ADSC-exos) in the wound healing process remain unclear.MaterialsThe effects of MSGMSC-exos and ADSC-exos on angiogenesis in wound healing were investigated in vitro using CCK-8, scratch assays, and tube formation assays. Subsequently, the promotion of wound healing by MSGMSC-exos and ADSC-exos was evaluated in vivo using a full-thickness wound defect model in mice. Immunohistochemistry was used to verify the effects of MSGMSC-exos and ADSC-exos on promoting collagen deposition, angiogenesis, and cell proliferation in the wound. Immunofluorescence staining was performed to investigate the role of MSGMSC-exos and ADSC-exos in modulating the inflammatory response in the wound. Furthermore, proteomic sequencing was conducted to investigate the functional similarities and differences between the proteomes of MSGMSC-exos and ADSC-exos, with key protein contents verified by ELISA.ResultsMSGMSC-exos exhibited similar effects as ADSC-exos in promoting the migration, proliferation, and tube formation of human umbilical vein endothelial cells (HUVECs) in vitro, with a comparable dose-dependent effect. In vivo experiments confirmed that MSGMSC-exos have similar wound healing-promoting functions as ADSC-exos. MSGMSC-exos promoted the neovascularization and maturation of blood vessels in vivo at a level comparable to ADSC-exos. Despite MSGMSC-exos showing less collagen deposition than ADSC-exos, they exhibited stronger anti-scar formation and anti-inflammatory effects. Proteomic analysis revealed that the proteins promoting wound healing in both MSGMSC-exos and ADSC-exos were relatively conserved, with ITGB1 identified as a critical protein for angiogenesis. Further differential analysis revealed that the functions specifically enriched in MSGMSC-exos and ADSC-exos reflected the functions of their source tissue.ConclusionsOur study confirms that MSGMSC-exos exhibit highly similar wound healing and angiogenesis-promoting functions compared to ADSC-exos, and the proteins involved in promoting wound healing in both are relatively conserved. Moreover, MSGMSC-exos show stronger anti-scar formation and anti-inflammatory effects than ADSC-exos. This suggests that MSGMSCs are a promising stem cell source with broad applications in wound healing treatment.

Microgravity’s effects on miRNA-mRNA regulatory networks in a mouse model of segmental bone defects

Rehabilitation from musculoskeletal injuries (MSKI) complicate healing dynamics typically by sustained disuse of bone and muscles. Microgravity naturally allows limb disuse and thus an effective model to understand MSKI. The current study examined epigenetic changes in a segmental bone defect (SBD) mouse model in a prolonged unloading condition after spaceflight (FLT). We further connected potential miRNA–mRNA regulatory pathways impacting bone healing. Here, SBD surgery was performed on nine-week-old male mice that were launched into space for approximately 4 weeks. Sham with no surgery and ground controls were included in the study. The midshaft of the ipsilateral femur (with callus on the surgical mice) as well as the ipsilateral quadriceps tissue were used for analysis. Femur and quadriceps had a distinct miRNA profile. There was a stronger surgery effect as observed by miRNA expression when compared to microgravity effects. Leukopoiesis, granulopoiesis, myelopoiesis of leukocytes, differentiation of myeloid leukocytes, and differentiation of progenitor cells were all altered because of surgery in the femur. The biological functions such as apoptosis, necrosis, and activation of cell migration and viability were altered because of surgery in quadriceps. Integrating the transcriptome and microRNA data indicated pronounced changes because of microgravity. According to pathway analysis, microgravity had a greater impact on the quadriceps tissue than the bone tissue in the absence of surgery. The altered biological functions resulting from microgravity were validated by integrating limited proteomics data to miRNA-mRNA. Thus, this study highlights the importance of dynamic interplay of gene-epigene regulations as they appear to be intrinsically interconnected and influence in combination for the biological outcome.

Analytical Probabilistic Modeling of Additive Manufacturing-Induced Process Defects and Experimental Validation

Analytical Probabilistic Modeling of Additive Manufacturing-Induced Process Defects and Experimental Validation

Optimization of thermal shock response spectrum as infrared thermography post-processing methodology using Latin hypercube sampling and analytical thermal N-layer model

In this work, we continue to develop and investigate the Thermal Shock Response Spectrum (TSRS) method as an alternative data processing method for infrared thermography (IRT). We focus on improving the current TSRS algorithm and present an optimization methodology for finding the optimal thermal Q-factor and characteristic frequency pair, which is based on the widely applied random sampling method. We show the qualitative relationship between the determined optimal characteristic frequency and the corresponding maximum difference in diffusion length between reference and defective models, as calculated by selecting a specific one-dimensional thermal N-layer model The investigations were performed on an inhomogeneous plate made of carbon fiber reinforced polymer (CFRP) with artificial square defects at different depths. Furthermore, two different heat sources were used: a xenon flash lamp and a laser. These sources are not only distinct by their underlying physics but also generate inherently different pulse shapes. To quantitatively estimate the contrast between defect and non-defect areas, and to compare these results with commonly used infrared thermography (IRT) data post-processing methods such as Pulse Phase Thermography (PPT) and Thermographic Signal Reconstruction (TSR), the Tanimoto criterion (TC) and signal-to-noise ratio (SNR) were used.

Platelet-rich fibrin associated to bovine bone induces bone regeneration in model of critical-sized calvaria defect of rats submitted to Zoledronic Acid therapy: PRF induces bone healing

Reconstruction of bone defects prior to implant installation is a challenge, especially when the patient uses bisphosphonates. Given this difficulty, many studies investigate biomaterials that can improve the bone regeneration process. In this context, this study aimed to investigate the effect of platelet-rich fibrin (PRF) and Bio-Oss (BO) on bone regeneration of rats submitted to critical-sized calvaria defects and treated with ZA. Thirty Wistar rats received a single dose of ZA (120 μg/kg) and after 7 days, were submitted to an 8 mm calvaria defect. The animals were divided into 5 groups (n=6): ZA, BO, PRF or BO+PRF; animals from control group did not receive ZA. All animals were euthanized 12 weeks after surgical procedure and calvaria collected to histological, histomorphometric and micro-CT analyses. BO+PRF increased the number of osteoblasts (33%) and osteoclasts (58%), as well as blood vessels (70%) and Type I collagen (52%) (p<0.05) compared to ZA group. In summary, the association of BO+PRF improved bone healing of large bone defect in rats receiving ZA and this may be an interesting approach for the treatment to be tested in patients under anti-resorptive therapy.

An automatic defect detection and localization method using imaging geometric features for sewer pipes

Accurate longitudinal localization of defects in sewer pipes is crucial for efficient maintenance and renewal. However, traditional closed-circuit television (CCTV)-based localization methods have been inefficient and imprecise, impeding real-time inspection performance. In this paper, we firstly point out that the inaccuracy of CCTV-based localization methods stems from the oversight of monocular imaging geometry, which leads to a deviation in sewer defect localization. Then, we propose an automated framework for sewer defect detection and longitudinal localization based on a deep-learning algorithm and monocular imaging geometry. Specifically, structural defects are qualitatively analyzed to explore their intrinsic correlation with the pipe wall. Then, the imaging geometry is leveraged to establish the projection relationship between the defects and the pipe joints. The longitudinal localization correction model for structural defects is then developed using the pipe diameter as the actual size. Our experiments show that this framework enhances the mean average precision (mAP) for multi-defects by 7.2 % and achieves a theoretical mean absolute error of 0.2 m and a practical mean absolute error of 0.28 m for defect localization, surpassing current research. Finally, with the generated detection results and localization records, the proposed framework can promote the efficiency of the sewer investigation and accelerate the development of intelligent sewer systems.

Oyster Mantle-Derived Exosomes Alleviate Osteoporosis by Regulating Bone Homeostasis

Osteoporosis is a major public health problem with an urgent need for safe and effective therapeutic interventions. The process of shell formation in oysters is similar to that of bone formation in mammals, and oyster extracts have been proven to exert osteoprotective effects. Oyster mantle is the most crucial organ regulating shell formation, in which exosomes play an important role. However, the effects of oyster mantle-derived exosomes (OMEs) on mammalian osteoporosis and the underlying mechanisms remain unknown. The OMEs investigated herein was found to carry abundant osteogenic cargos. They could also survive hostile gastrointestinal conditions and accumulate in the bones following oral administration. Moreover, they promoted osteoblastic differentiation and inhibited osteoclastic differentiation simultaneously. Further mechanistic examination revealed that OMEs likely promoted osteogenic activity by activating PI3K/Akt/β-catenin pathway in osteoblasts and blunted osteoclastic activity by inhibiting NF-κB pathway in osteoclasts. These favorable pro-osteogenic effects of OMEs were also corroborated in a rat femur defect model. Importantly, oral administration of OMEs effectively attenuated bone loss and improved the bone microstructure in ovariectomy-induced osteoporotic mice, and demonstrating excellent biosafety. The mechanistic insights from our data support that OMEs possess promising therapeutic potential against osteoporosis.

BMP2 enhance the osteogenic effect of BMSCs-derived exosomes in skull defect of diabetic rats

Diabetic patients often face poor repair of bone defects, which may be related to the reduced osteogenic capacity of bone marrow mesenchymal stem cells (BMSCs) and the polarization of M1/M2 macrophage imbalance leading to an inflammatory response. The ability of BMSC-derived exosomes (BMSC-Exos) and BMP2 to exert both bone tissue regeneration and immunomodulation is expected to resolve this clinical dilemma. In this study, we demonstrate that exosomes derived from BMP2-treated BMSCs (BMP2-Exos) in a diabetic microenvironment exhibit enhanced osteogenic effects. Additionally, compared to the blank control group, macrophages stimulated by BMP2-Exos were more polarized towards the M2 type. These results were verified in vivo by GelMA loaded exosomes in the diabetic rat skull defect model. Importantly, we found that BMP2-Exos can upregulate the PI3K/AKT signaling pathway in diabetic BMSCs and improved osteogenic function and M2 macrophage polarization in diabetes-impaired BMSC-Exos in vitro. In conclusion, the present study revealed that BMP2 pretreatment can enhance the ability of BMSC-Exos to promote osteogenesis in diabetic bone defect areas, provides a preliminary exploration of the underlying mechanisms. Our study provided important experimental basis and innovative ideas for the application of exosomes therapy in the field of bone tissue regeneration.

Corrole-based Photothermal Nanocomposite Hydrogel with Nitric Oxide Release for Diabetic Wound Healing.

The management of chronic diabetic wounds remains a significant challenge due to persistent bacterial infections and impaired angiogenesis. Herein, we reported a nanocomposite hydrogel (M/P-SNO/G) incorporated with M/P-SNO nanoparticles engineered by supramolecular assembly of the photosensitizing mono-carboxyl corrole (MCC) and S-nitrosothiol-modified polyethylene glycol (mPEG-SNO) for synergistic photothermal therapy (PTT)/nitric oxide (NO) treatment of diabetic wounds. The strong π-π interaction among aggregated MCC in M/P-SNO enhances the optical absorption and photothermal ability, thereby facilitating the precise release of NO upon laser irradiation. The hydrogel matrix, composed of oxidized hyaluronic acid and carboxymethyl chitosan crosslinked by Schiff-base, demonstrates good injectability and self-healing characteristics, providing an ideal environment for wound repair. As expected, M/P-SNO/G exhibits a desirable photothermal performance and a controlled laser-responsive NO release, realizing enhanced bactericidal effect and anti-biofilm ability in vitro. In a full-thickness skin defect model on diabetic mice, M/P-SNO/G has proven effective in bacteria clearance and angiogenesis, significantly accelerating wound healing. This study presents a feasible supramolecular strategy to develop diabetic wound dressings with synergistic PTT/NO treatment. STATEMENT OF SIGNIFICANCE: Developing advanced dressings that simultaneously eliminate bacteria and accelerate wound recovery is essential for treating diabetic wounds. This study developed a nanocomposite hydrogel (M/P-SNO/G) featuring the synergistic effect of photothermal therapy (PTT) and nitric oxide (NO) treatment to accelerate infected diabetic wound healing. M/P-SNO NPs within the hydrogel are self-assembled through the hydrophobic photosensitizing mono-carboxyl corrole (MCC) and the hydrophilic NO-releasing polymer (mPEG-SNO), where highly aggregated MCC molecules ensure superior photothermal performance. Meanwhile, the temperature increase induced by the photothermal effect activates NO release from the hydrogel. Under 660 nm laser irradiation, M/P-SNO/G demonstrates a PTT/NO synergy to effectively inhibit bacterial proliferation and promote angiogenesis, offering significant benefits in diabetic wound repair and further expanding the biomedical applications of corroles.

Osteogenic potential of esculetin-loaded chitosan nanoparticles in microporous alginate/polyvinyl alcohol scaffolds for bone tissue engineering.

Bone tissue engineering (BTE) is an emerging strategy for the treatment of critical bone defects using biomaterials and cells. Esculetin (ES), a coumarin phytocompound, has demonstrated therapeutic potential, although its osteogenic effects remain insufficiently explored. Owing to its hydrophobic nature, which limits its bioavailability, this study developed a drug delivery system using chitosan nanoparticles (nCS) to achieve sustained release of ES. These ES-loaded nCS nanoparticles were incorporated into biocomposite scaffolds composed of alginate (Alg) and polyvinyl alcohol (PVA) using freeze-drying. The synthesized nCS-ES nanoparticles exhibited spherical morphology with a uniform size distribution, ranging from 105 to 117 nm, and demonstrated excellent entrapment efficiencies (94.07 to 97.61 %). The nanoparticles displayed high zeta potential values (+27.8 to +33.2 mV), ensuring stable dispersion. The biocomposite scaffolds exhibited a uniform distribution of pores, with pore diameters ranging from 106 ± 14 μm to 112 ± 14 μm. The biocomposite scaffolds exhibited excellent swelling, protein adsorption, biodegradation, and biomineralization properties. The ES-loaded scaffolds showed sustained ES release, promoting osteogenesis in vitro, with the activation of the Wnt/β-catenin signaling pathway. In vivo studies using a rat tibial bone defect model further confirmed that these scaffolds stimulated new bone formation, highlighting the ES's potential for BTE applications.

Catechol-grafted chitosan-based antioxidant hydrogel with rapid self-healing property for wound healing.

Chronic wounds, particularly those with non-healing ulcers, show high levels of oxidant stress, such as excessive reactive oxygen species (ROS), which delays the healing process. Bacterial infections in wounds increase the need for antibiotics, which brings up serious concerns regarding antibiotic resistance. The innovative antibiotic-free strategies to endow the hydrogels with antibacterial and antioxidant features including the grafting of ROS-scavenging moieties onto the hydrogel structure are in high demand for wound management. Herein, an antibacterial and antioxidant hydrogel with rapid self-healing performance was fabricated via the dynamic borate ester cross-linkages between catechol-grafted chitosan (CS-CA) and polyvinyl alcohol in the presence of borax with the incorporation of ellagic acid (EA). Benefiting from the catechol groups from EA and CS-CA, the resulting hydrogel exhibited desirable adhesive property, excellent antioxidant and intensified antibacterial dual functions. Furthermore, the hydrogel demonstrated remarkable biocompatibility and pH-responsive behavior for the controlled release of EA, attributed to the reversible characteristics of borate ester linkages. Notably, these multifunctional hydrogels exhibited substantial regenerative capabilities in wound healing, as evidenced by in vivo assessments conducted on a full-thickness skin defect model, highlighting their considerable potential as wound dressings for effective wound management.

An InVivo Assessment of Different Mesenchymal Stromal Cell Tissue Types and Their Differentiation State on a Shape Memory Polymer Scaffold for Bone Regeneration.

A combined biomaterial and cell-based solution to heal critical size bone defects in the craniomaxillofacial area is a promising alternative therapeutic option to improve upon autografting, the current gold standard. A shape memory polymer (SMP) scaffold, composed of biodegradable poly(ε-caprolactone) and coated with bioactive polydopamine, was evaluated with mesenchymal stromal cells (MSCs) derived from adipose (ADSC), bone marrow (BMSC), or umbilical cord (UCSC) tissue in their undifferentiated state or pre-differentiated toward osteoblasts for bone healing in a rat calvarial defect model. Pre-differentiating ADSCs and UCSCs resulted in higher new bone volume fraction (15.69% ± 1.64%) compared to empty (i.e., untreated) defects and scaffold-only (i.e., unseeded) groups (4.41% ± 1.11%). Notably, only differentiated UCSCs exhibited a significant increase in new bone volume, surpassing both undifferentiated UCSCs and unseeded scaffolds. Further, differentiated ADSCs and UCSCs had significantly higher trabecular numbers than their undifferentiated counterparts, unseeded scaffolds, and untreated defects. Although the mineral density regenerated within the unseeded scaffold surpassed that achieved with cell seeding, the connectivity of this bone was diminished, as the regenerated tissue confined itself to the spherical morphology of the scaffold pores. The SMP scaffold alone, with undifferentiated BMSCs, with undifferentiated and differentiated ADSCs, and differentiated UCSCs (29.72 ± 1.49 N) demonstrated significant osseointegration compared to empty defects (14.34 ± 2.21 N) after 12 weeks of healing when assessed by mechanical push-out testing. Based on these results and tissue availability to obtain the cells, pre-differentiated ADSCs and UCSCs emerge as particularly promising candidates when paired with the SMP scaffold for repairing critical size bone defects in the craniofacial skeleton.

Bone regeneration in rabbit cranial defects: 3D printed polylactic acid scaffolds gradually enriched with marine bioderived calcium phosphate

ObjectiveThis study aimed to evaluate the in vivo biocompatibility, mechanical performance and osteoconductive potential of 3D-printed polylactic acid (PLA) scaffolds enriched with marine bioderived calcium phosphate (bioCaP) for bone tissue engineering. Materials and MethodsPLA-bioCaP composite scaffolds were specifically designed for the rabbit cranial defect model by 3D printing, with a uniform distribution of open square-shaped pores and contributions in bioCaP. Physicochemical and mechanical characterization and the evaluation of biological response are presented. ResultsThe scaffolds demonstrated mechanical properties comparable to human bones, integration with the host bone, and osteoconductive behavior promoting cell ingrowth from the defect edge. Strong mineralized tissue ingrowth through the scaffolds’ pores was observed, providing notable support to the host bone. In quantitative terms, micro-CT and histomorphometry analysis post-implantation revealed no significant differences in bone regeneration across all groups. ConclusionThe 3D-printed scaffolds with perpendicular patterning, open porosity, and proposed composition displayed satisfactory mechanical properties, biocompatibility, and osteoconductive response. The scaffolds promoted bone regeneration at similar levels as the PLA. The highest contribution of bioCaP promoted a positive influence in certain histomorphometric parameters; however, it did not significantly improve their osteogenic capability. Further research is required to optimize scaffold composition and enhance their osteogenic potential. Clinical RelevanceThis study presents a significant advancement in bone tissue engineering through the development of personalized composite scaffolds for bone-related applications. The clinical implications of this research are profound, especially considering the increasing demand for functional bone regeneration technologies capable of producing cost-effective producing cost-effective customized scaffolds.

Efficacy of Bone Regeneration Cell Therapy Using Mesenchymal Stem Cells Originating from Embryonic Stem Cells in Animal Models; Bone Defects and Osteomyelitis.

Bone defects are commonly encountered due to accidents, diseases, or aging, and the demand for effective bone regeneration, particularly for dental implants, is increasing in our aging society. Mesenchymal stem cells (MSCs) are promising candidates for regenerative therapies; however, obtaining sufficient quantities of these cells for clinical applications remains challenging. DW-MSCs, derived from embryonic stem cells and developed by Daewoong Pharmaceutical, exhibit a robust proliferative capacity even after extensive culture. This study explores the therapeutic potential of DW-MSCs in various animal models of bone defects. DW-MSCs were expanded for over 13 passages for in vivo use in rat and canine models of bone defects and osteomyelitis. The research focused on the in vivo osteogenic differentiation of DW-MSCs, the establishment of a fibrin-based system for bone regeneration, the assessment of bone repair following treatment in animal models, and comparisons with commercially available bone grafts. Results showed that DW-MSCs exhibited superior osteogenic differentiation compared to other materials, and the fibrinization process not only preserved but enhanced their proliferation and differentiation capabilities through a 3D culture effect. In both bone defect models, DW-MSCs facilitated significant bone regeneration, reduced inflammatory responses in osteomyelitis, and achieved effective bone healing. The therapeutic outcomes of DW-MSCs were comparable to those of commercial bone grafts but demonstrated qualitatively superior bone tissue restructuring. Our findings suggest that DW-MSCs offer a promising approach for bone regeneration therapies due to their high efficacy and anti-inflammatory properties.

Optimal Suturing Techniques in Patch-Bridging Reconstruction for Massive Rotator Cuff Tears: A Finite Element Analysis

PurposeTo use a finite element method to construct a patch-bridge repair model for MRCTs and investigate the effects of different suture methods and knot numbers on postoperative biomechanics. MethodsA finite element model based on intact glenohumeral joint data was used for a biomechanical study. A full-thickness defect and retraction model of the supraspinatus tendon simulated MRCTs. Patch, suture, and anchor models were constructed, and the Marlow method was used to assign the material properties. Three suturing models were established: 1-knot simple, 1-knot mattress, and 2-knot mattress. The ultimate failure load, failure mode, stress distribution of each structure, and other biomechanical results of the different models were calculated and compared. ResultsThe ultimate failure load of the 1-knot mattress suture (71.3 N) was 5.6% greater than that of the 1-knot simple suture (67.5 N), while that (81.5 N) of the 2-knot mattress was 14.3% greater than that of the 1-knot mattress. The stress distribution on the patch and supraspinatus tendon was concentrated on suture perforation. Failure of the bridging reconstruction mainly occurred at the suture perforation of the patch, and the damage forms included cutting-through and isthmus pull-out. ConclusionA finite element model for the patch-bridging reconstruction of MRCTs was established, and patch-bridging restored the mechanical integrity of the rotator cuff. The 2-knot mattress suture was optimal for patch-bridging reconstruction of MRCTs.

TGF-β3 Restrains Osteoclastic Resorption Through Autophagy

While TGF-β3 promoted defect healing in a primate baboon skull defect model and patients, it remains unclear whether TGF-β3 affects the formation of osteoclasts and bone resorption between osteogenesis and osteolysis. Analysis of the full transcriptome of hPDLSCs (human periodontal ligament stem cells) revealed that the expression of RANKL was significantly up-regulated after TGF-β3 treatment during osteogenesis, which suggests its involvement in clock-controlled autophagy in bone metabolism. TRAP staining and bone resorption lacunae were used to assess the osteoclasts formed from RANKL-induced differentiated BMMs. During osteoclast differentiation, the characteristics of autophagy regulated by TGF-β3 were observed in BMMs through MDC staining, transmission electron microscopy, and LC3 immunofluorescence. The expression of related genes and proteins were detected on the sixth day in mCherry-EGFP-LC3B lentivirus-transfected BMMs using RT-qPCR and WB. Finally, a trans-well co-culture system was used to evaluate the effects of osteogenic differentiated hPDLSCs treated with TGF-β3 on the osteoclastic differentiation of BMMs. The results showed 10 ng/mL of TGF-β3 significantly suppressed osteoclastic differentiation and bone resorption in BMMs (p &lt; 0.05 vs. RANKL). In particular, TGF-β3 augments the expression of LC3-II to stimulate autophagy, consequently restraining osteoclastic resorption. These findings provide a molecular basis and are beneficial to illustrate the potential druggability of TGF-β3 in osteoporotic diseases.

Engineered Osteochondral Scaffolds with Bioactive Cartilage Zone for Enhanced Articular Cartilage Regeneration.

Despite progress, osteochondral (OC) tissue engineering strategies face limitations in terms of articular cartilage layer development and its integration with the underlying bone tissue. The main objective of this study is to develop a zonal OC scaffold with native biochemical signaling in the cartilage zone to promote articular cartilage development devoid of cells and growth factors. Herein, we report the development and in vivo assessment of a novel gradient and zonal-structured scaffold for OC defect regeneration. The scaffold system is composed of a mechanically supportive 3D-printed template containing decellularized cartilage extracellular matrix (ECM) biomaterial in the cartilage zone that possesses bioactive characteristics, such as chemotactic activity and native tissue biochemical composition. OC scaffolds with a bioactive cartilage zone were implanted in vivo in a rabbit osteochondral defect model and assessed for gross morphology, matrix deposition, cellular distribution, and overall tissue regeneration. The scaffold system supported recruitment and infiltration of host cells into the cartilage zone of the graft, which led to increased ECM deposition and physiologically relevant articular cartilage tissue formation. Semi-quantitative ICRS scoring (overall score double for OC scaffold with bioactive cartilage zone compared to PLA scaffold) further confirm the bioactive scaffold enhanced articular cartilage engineering. This strategy of designing bioactive scaffolds to promote endogenous cellular infiltration can be a much simpler and effective approach for OC tissue repair and regeneration.