Aims

In our previous research, we have found that melatonin (MEL) affects the osteoporotic process. By balancing bone remoulding, autophagy is involved in age-related bone loss. However, as a regulator of autophagy, whether MEL influences senile osteoporosis via regulating autophagy remains unclear.

Aims. Autologous bone graft (ABG) is considered the ‘gold standard’ among graft materials for bone regeneration. However, complications including limited availability, donor site morbidity, and deterioration of regenerative capacity over time have been reported. P-15 is a synthetic peptide that mimics the cell binding domain of Type-I collagen. This peptide stimulates new bone formation by enhancing osteogenic cell attachment, proliferation, and differentiation. The objective of this study was to conduct a systematic literature review to determine the clinical efficacy and safety of P-15 peptide in bone regeneration throughout the skeletal system. Methods. PubMed, Embase, Web of Science, and Cochrane Library were searched for relevant articles on 13 May 2023. The systematic review was reported according to the PRISMA guidelines. Two reviewers independently screened and assessed the identified articles. Quality assessment was conducted using the methodological index for non-randomized studies and the risk of bias assessment tool for randomized controlled trials. Results. After screening, 28 articles were included and grouped by surgical indication, e.g. maxillofacial procedures (n = 18), spine (n = 9), and trauma (n = 1). Published results showed that P-15 peptide was effective in spinal fusion (n = 7) and maxillofacial (n = 11), with very few clinically relevant adverse events related to P-15 peptide. Conclusion. This systematic literature review concluded that moderate- (risk of bias, some concern: 50%) to high-quality (risk of bias, low: 46%) clinical evidence exists showing equivalent safety and efficacy in bone regeneration using a P-15 peptide enhanced bone graft substitute compared to ABG. P-15 peptide is safe and effective, resulting in rapid bone formation with a low probability of minor complications. Cite this article: Bone Joint Res 2025;14(2):77–92

The February 2025 Research Roundup³⁶⁰ looks at: Walk your way to longer life: quantifying physical activity’s role in extending longevity; Is information about musculoskeletal malignancies from large language models or web resources at a suitable reading level for patients?; Contemporary surgical management of osteosarcoma and Ewing’s sarcoma; L-arginine and tendon healing; What you can’t hear might not stress you out as much.

Aims

The involvement of long non-coding RNA (lncRNA) in bone marrow mesenchymal stem cell (MSC) osteogenic differentiation during osteoporosis (OP) development has attracted much attention. In this study, we aimed to disclose how LINC01089 functions in human mesenchymal stem cell (hMSC) osteogenic differentiation, and to study the mechanism by which LINC01089 regulates MSC osteogenesis.

Aims. Mesenchymal stem cells (MSCs) are usually cultured in a normoxic atmosphere (21%) in vitro, while the oxygen concentrations in human tissues and organs are 1% to 10% when the cells are transplanted in vivo. However, the impact of hypoxia on MSCs has not been deeply studied, especially its translational application. Methods. In the present study, we investigated the characterizations of human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) in hypoxic (1%) and normoxic (21%) atmospheres with a long-term culture from primary to 30 generations, respectively. The comparison between both atmospheres systematically analyzed the biological functions of MSCs, mainly including stemness maintenance, immune regulation, and resistance to chondrocyte apoptosis, and studied their joint function and anti-inflammatory effects in osteoarthritis (OA) rats constructed by collagenase II. Results. We observed that long-term hypoxic culture surpassed normoxic atmosphere during hUC-MSCs culture in respect of promoting proliferation, anti-tumorigenicity, maintaining normal karyotype and stemness, inhibiting senescence, and improving immunoregulatory function and the role of anti-apoptosis in chondrocytes. Furthermore, we demonstrated that the transplantation of long-term hypoxic hUC-MSCs (Hy-MSCs) had a better therapeutic effect on OA rats compared with the hUC-MSCs cultured in the normoxic atmosphere (No-MSCs) in terms of the improved function and swelling recovery in the joints, and substantially inhibited the secretion of pro-inflammatory factors, which effectively alleviated cartilage damage by reducing the expression of matrix metallopeptidase 13 (MMP-13). Conclusion. Our results demonstrate that Hy-MSCs possess immense potential for clinical applications via promoting stemness maintenance and enhancing immunoregulatory function. Cite this article: Bone Joint Res 2024;13(12):763–777

Addressing bone defects is a complex medical challenge that involves dealing with various skeletal conditions, including fractures, osteoporosis (OP), bone tumours, and bone infection defects. Despite the availability of multiple conventional treatments for these skeletal conditions, numerous limitations and unresolved issues persist. As a solution, advancements in biomedical materials have recently resulted in novel therapeutic concepts. As an emerging biomaterial for bone defect treatment, graphene oxide (GO) in particular has gained substantial attention from researchers due to its potential applications and prospects. In other words, GO scaffolds have demonstrated remarkable potential for bone defect treatment. Furthermore, GO-loaded biomaterials can promote osteoblast adhesion, proliferation, and differentiation while stimulating bone matrix deposition and formation. Given their favourable biocompatibility and osteoinductive capabilities, these materials offer a novel therapeutic avenue for bone tissue regeneration and repair. This comprehensive review systematically outlines GO scaffolds’ diverse roles and potential applications in bone defect treatment. Cite this article: Bone Joint Res 2024;13(12):725–740

Aim. Periprosthetic joint infections follow 1-3% of arthroplasty surgeries, with the biofilm nature of these infections presenting a significant treatment challenge. 1. Prevention strategies include antibiotic-loaded bone cement; however, increases in cementless procedures means there is an urgent need for alternative local antimicrobial delivery methods. 2. A novel, ultrathin, silica-based sol-gel technology is evaluated in this research as an anti-infective coating for orthopaedic prosthetic devices, providing local antibiotic release following surgery. Method. Reduction in clinically relevant microbial activity and biofilm reduction by antimicrobial sol-gel coatings, containing a selection of antibiotics, were assessed via disc diffusion and microdilution culture assays using the Calgary biofilm device. 3. Proliferation, morphology, collagen, and calcium production by primary bovine osteoblasts cultured upon antibiotic sol-gel surfaces were examined, and cytotoxicity evaluated using Alamar blue staining and lactate dehydrogenase assays. Concentrations of silica, calcium and phosphorus compounds within the cell layer cultured on sol-gel coatings and concentrations eluted into media, were quantified using ICP-OES. Furthermore, cellular phenotype was assessed using alkaline phosphatase activity with time in culture. Results. Low antibiotic concentrations within sol-gel had an inhibitory effect on clinically relevant biofilm growth, for example 0.8 mg ml. -1. tobramycin inhibited clinically isolated S. aureus (MRSA) growth with an 8-log reduction in viable colony forming units. There was no significant difference in metabolic activity between untreated and sol-gel exposed primary bovine osteoblasts in elution-based assays. Reduction (2-fold) in metabolic activity in direct contact assays after 48 hours exposure was likely to be due to increased osteoinduction, whereas no impact upon cell proliferation were observed (p=0.92 at 14 days culture). The morphology of primary osteoblasts was unaffected by culture on sol-gel coatings and collagen production was maintained. Calcium containing nodule production within bovine osteoblastic cells was increased 16-fold after 14 days culture upon sol-gel. Conclusions. The ultrathin sol-gel coating showed low cytotoxicity, strong biofilm reducing activity and antimicrobial activity, which was comparable to antibiotics alone, demonstrating that sol-gel delivery of antibiotics could provide local antimicrobial effects to inhibit PJI growth without the need for bone cement. Future work will develop and evaluate sol-gel performance in an ex vivo explant bone infection model which will reduce the need for animal experimentation

Aim. Biomaterial-associated infections (BAI) present a formidable clinical challenge. Bioactive glasses (BG) have proven highly successful in diverse clinical applications, especially in dentistry and orthopaedics. In this study, we aimed to determine the effect of three commonly used BG composition and particle sizes on cell and bacterial attachment and growth. Our focus is on understanding the changes in pH and osmotic pressure in the surrounding environment during glass degradation. Method. First, three different melt-derived glasses were characterized by analyzing particle size and glass network structure using Raman and NMR. The different glasses were then tested in vitro by seeding 4x 10. 4. cells/well (SaOS Cell line) in a 48 well plate. After a pre-incubation period of 72 hours, the different BGs and particle sizes were added to the cells and the pH value, ion release and live/dead staining was measured every hour. The effect of BG against bacteria (S. epidermidis) was analyzed after 24 and 72 hours of treatment by using XTT viability assay and CFU counting by plating out the treated aliquot agar to estimate the viable bacteria cells. Results. All three BG compositions tested showed a significant increase in pH, which was highest in BG composition 45S5 with a value of 11 compared to the other BG compositions 10 and 9 in S53P4 and 13-93 respectively. This strong increase in the pH in all BG samples tested results in a strongly reduced cell viability rate of more than 75% compared to the untreated control and 6-fold reduction in bacterial viability compared to the untreated control. The live/ dead assay also showed an increased cell viability with increasing glass particle size (i. e smallest glass particle < 25% viable cell and largest glass particle> 65% viable cell). The ion release concentration over 50 h showed an increase in sodium ions to 0.25 mol/L, calcium to 0.003 mol/L and a decrease in phosphorus. Conclusions. These results show that the composition of the bioactive glass and the choice of particle size have a major influence on subsequent applications. In addition to the different compositions of the BG, particle size and additional medium change also influence the pH and ion release, and therefore also on cells or bacteria viability. The sizes of the bioactive glass particle are inversely proportional to it. Further tests are necessary to develop custom design BG compositions, which simultaneously stimulate osteoblasts proliferation and prevent microbial adhesion

Aims. Osteoarthritis (OA) is a common degenerative disease. PA28γ is a member of the 11S proteasome activator and is involved in the regulation of several important cellular processes, including cell proliferation, apoptosis, and inflammation. This study aimed to explore the role of PA28γ in the occurrence and development of OA and its potential mechanism. Methods. A total of 120 newborn male mice were employed for the isolation and culture of primary chondrocytes. OA-related indicators such as anabolism, catabolism, inflammation, and apoptosis were detected. Effects and related mechanisms of PA28γ in chondrocyte endoplasmic reticulum (ER) stress were studied using western blotting, real-time polymerase chain reaction (PCR), and immunofluorescence. The OA mouse model was established by destabilized medial meniscus (DMM) surgery, and adenovirus was injected into the knee cavity of 15 12-week-old male mice to reduce the expression of PA28γ. The degree of cartilage destruction was evaluated by haematoxylin and eosin (HE) staining, safranin O/fast green staining, toluidine blue staining, and immunohistochemistry. Results. We found that PA28γ knockdown in chondrocytes can effectively improve anabolism and catabolism and inhibit inflammation, apoptosis, and ER stress. Moreover, PA28γ knockdown affected the phosphorylation of IRE1α and the expression of TRAF2, thereby affecting the mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) signalling pathways, and finally affecting the inflammatory response of chondrocytes. In addition, we found that PA28γ knockdown can promote the phosphorylation of signal transducer and activator of transcription 3 (STAT3), thereby inhibiting ER stress in chondrocytes. The use of Stattic (an inhibitor of STAT3 phosphorylation) enhanced ER stress. In vivo, we found that PA28γ knockdown effectively reduced cartilage destruction in a mouse model of OA induced by the DMM surgery. Conclusion. PA28γ knockdown in chondrocytes can inhibit anabolic and catabolic dysregulation, inflammatory response, and apoptosis in OA. Moreover, PA28γ knockdown in chondrocytes can inhibit ER stress by promoting STAT3 phosphorylation. Cite this article: Bone Joint Res 2024;13(11):659–672

Introduction. Homogenous and consistent preparations of mesenchymal stem cells (MSCs) can be acquired by selecting them for integrin α10β1 (integrin a10-MSCs). Safety and efficacy of intra-articular injection of allogeneic integrin a10-MSCs were shown in two post-traumatic osteoarthritis horse studies. The current study investigated immunomodulatory capacities of human integrin a10-MSCs in vitro and their cell fait after intra-articular injection in rabbits. Method. The concentration of produced immunomodulatory factors was measured after licensing integrin a10-MSCs with pro-inflammatory cytokines. Suppression of T-cell proliferation was determined in co-cultures with carboxyfluorescein N-succinimidyl ester (CFSE) labelled human peripheral blood mononuclear cells (PBMCs) stimulated with anti-CD3/CD28 and measuring the CFSE intensity of CD4+ cells. Macrophage polarization was assessed in co-cultures with differentiated THP-1 cells stimulated with lipopolysaccharide and analysing the M2 macrophage cell surface markers CD163 and CD206. In vivo homing and regeneration were investigated by injecting superparamagnetic iron oxide nanoparticles conjugated with Rhodamine B-labeled human integrin a10-MSCs in rabbits with experimental osteochondral defects. MSC distribution in the joint was followed by MRI and fluorescence microscopy. Result. The production of the immunomodulatory factors indoleamine 2,3-dioxygenase and prostaglandin E2 was increased after inflammatory licensing integrin a10-MSCs. Co-cultures with integrin a10-MSCs suppressed T-cell proliferation and increased the frequency of M2 macrophages. In vivo injected integrin a10-MSCs homed to osteochondral defects and were detected in the repair tissue of the defects up to 10 days after injection, colocalized with aggrecan and type II collagen. Conclusion. This study showed that human integrin a10-MSCs have immunomodulatory capacities and in vivo can home to the site of osteochondral damage and directly participate in cartilage regeneration. This suggests that human integrin α10β1-selected MSCs may be a promising therapy for osteoarthritis with dual mechanisms of action consisting of immunomodulation and homing to damage followed by early engraftment and differentiation into chondrocyte-like cells that deposit hyaline cartilage matrix molecules

Introduction. Osteoarthritis (OA) is a prevalent joint disorder characterized by cartilage degeneration, inflammation, and pain. Current treatments provide only symptomatic relief, necessitating novel molecular targets. The caspase family, known for its roles in apoptosis and inflammation regulation, may additionally influence crucial processes for cartilage homeostasis such as differentiation and proliferation. However, the specific roles of individual caspases in OA pathogenesis remain unclear. This study aims to investigate the involvement of the caspase family in OA and as potential targets for therapy, with a focus on caspase-1 and -8. Method. Chondrocytes from both healthy and OA donors were cultured in 2D and 3D culture models and stimulated with TNF-α or IL-1β. The expression and activation of caspase-1 and -8 was assessed using RT-PCR, ELISA. Transcriptome analysis of OA and healthy cartilage samples, along with Mendelian randomization (MR) analysis were conducted to explore the involvement of caspase family in OA and to assess its potential as therapeutic targets. Result. Higher expression levels of caspase-1, -8 were observed in OA cartilage compared to healthy cartilage. TNF-α stimulation increased their expression in both healthy and OA chondrocytes, while IL-1β had limited impact. Caspase-8 expression was causally associated with knee OA in MR analysis, suggesting a potential therapeutic target. The caspase-1 inhibitor VX-765 mildly reduced chondrocyte viability, with no significant effect in the presence of TNF-α. While the caspase-8 inhibitor Z-IETD-FMK exhibited slight enhancements in cell viability, these improvements were not statistically significant. Nevertheless, its effectiveness significantly increased in the presence of TNF-α. Conclusion. This study highlights the involvement of caspase-1 and caspase-8 in OA pathology, with caspase-8 emerging as a potential therapeutic target for knee OA treatment. Further investigation into the roles of caspase-1 and -8 in OA pathophysiology, including the efficacy and potential side effects of their corresponding inhibitors, is warranted. Acknowledgements. Funding Inter-Action/Inter-Excellence project (BTHA-JC-2022-36/LUABA22019)

Introduction. Tendon ruptures represent one of the most common acute tendon injuries in adults worldwide, affecting millions of people anually and becoming more prevalent due to longer life expectancies and sports activities. Current clinical treatments for full tears are unable to completely restore the torn tendons to their native composition, structure and mechanical properties. To address this clinical challenge, tissue-engineered substitutes will be developed to serve as functional replacements for total tendon ruptures that closely resemble the original tissue, restoring functionality. Method. Water borne polyurethanes (WBPU) containing acrylate groups, specifically polyethylene glycol methacrylate (PEGMA) or 2-hydroxyethyl methacrylate (HEMA), were combined with mouse mesenchymal stem cells (MoMSCs) and heparin sodium to formulate bioinks for the fabrication of scaffolds via extrusion-based 3D bioprinting. Result. The biocompatibility of acrylated-WBPUs was confirmed in 2D with MoMSCs using lactate dehydrogenase assay, DNA assay and live/dead assays. Cell-laden scaffolds were 3D-bioprinted by encapsulating MoMSCs at varying cell densities within the acrylated WBPUs. The resulting 3D structures support cell viability and proliferation within the scaffolds, as confirmed by live/dead assay, lactate dehydrogenase assay and DNA assays. Differentiation studies in the 3D-bioprinted scaffolds demonstrated the phenotype transition of MoMSCs toward tenocytes through gene expression and protein deposition analysis. The inclusion of sodium heparin in the bioinks revealed increased synthesis of matrix assembly proteins within the 3D-bioprinted constructs. Conclusion. The developed bioinks were biocompatible and printable, supporting cell viability within the 3D-bioprinted scaffold. The fabricated cell-laden constructs sustained cell proliferation, differentiation, and tissue formation. The addition of heparin sodium enhanced tissue formation and organization, showing promising results for the regeneration of tendon total ruptures. Principio del formularioThis work was supported by the Spanish State Research Agency (AEI) under grant No CPP2021-008754. The authors would like to thank their partners in the project, which are in charge of the synthesis of heparin sodium and acrylated-WBPUs

Introduction. Bioactive glasses (BGs) promote osteogenic differentiation of bone progenitor cells by releasing therapeutically active ions. The well-described 45S5-BG (in mol%: SiO. 2. 46.13; P. 2. O. 5. 2.60; CaO 26.91; Na. 2. O 24.35) was supplemented with CaF. 2. and NaF being added to the batch at nominal 5 (F5-BG) and 25 mol% (F25-BG), respectively. While the effect on physical and chemical properties has already been characterized, the biological properties require further studies. This study investigates the effects of fluoride-supplemented BGs on the osteogenic and angiogenic properties of human bone marrow mesenchymal stromal cells (BMSCs) in vitro. Method. BMSCs were co-cultured with melt-derived 45S5-BG, F5-BG, or F25-BG in ascending concentrations (1, 2 and 3 mg/ml). At 7 days, cell number was determined by 4,6-diamidine-2-phenylindole (DAPI) staining and cell viability by fluorescein diacetate (FDA) assay. The osteogenic potential of the BGs was evaluated through alkaline phosphatase (ALP) gene expression and activity, along with bone morphogenetic protein-2 (BMP2) gene expression and protein concentration. Vascular endothelial growth factor (VEGF) gene expression and protein concentration assessed angiogenic potential. As control, BMSCs were cultured without BG exposure. Result. All BGs significantly promoted cell number and viability, with F25-BG showing the highest count at 3 mg/ml. Osteogenic markers showed a significant decrease in ALP gene expression and activity, especially at higher concentrations. All BG groups demonstrated increased BMP2 protein concentration and gene expression compared to the control, with higher BG and fluoride concentrations correlating with greater increases in BMP2. VEGF gene expression increased in all analysed BGs. The fluoride-free BG group had the highest VEGF protein concentrations, while the F25 BG group showed the highest VEGF gene expression. Conclusion. The fluoride-substituted BGs exhibit excellent cytocompatibility, enhance BMSC proliferation and positively affect BMP2 gene expression and levels, suggesting their potential for osteogenic differentiation. Further research is necessary to assess their proangiogenic effect and potential advantages over 45S5-BG

Introduction. The objective of the work is construction of a multi-bioactive scaffold based on that allows a space/time control over the regeneration of damaged bones by Medication-Related Osteonecrosis of the Jaw using a minimal invasive approach based on the injection of the fast-degrading pro neuro and angiogenic ELR (Elastin-Like Recombinamers) based hydrogels. Method. Chemical crosslinking facilitated the creation of multi-bioactive scaffolds using ELRs with reactive groups. Cell-loaded multi-bioactive scaffolds, prepared and incubated, underwent evaluation for adhesion, proliferation, angiogenic, and neurogenic potential. In vitro assessments utilized immunofluorescence staining and ELISA assays, while live-recorded monitoring and live-dead analysis ensured cytocompatibility. In rat and rabbit models, preformed scaffolds were subcutaneously implanted, and the regenerative process was evaluated over time. Rabbit models with MRONJ underwent traditional or percutaneous implantation, with histological evaluation following established bone histological techniques. Result. A 3D scaffold using ELR that combines various peptides with different degradation rates to guide both angiogenesis and neurogenesis has been developed. Notably, scaffolds with different degradation rates promoted distinct patterns of vascularization and innervation, facilitating integration with host tissue. This work demonstrates the potential for tailored tissue engineering, where the scaffold's bioactivities and degradation rates can control angiogenesis and neurogenesis. In an animal model of medication-related osteonecrosis of the jaw (MRONJ), the scaffold showed promising results in promoting bone regeneration in a necrotic environment, as confirmed by histological and imaging analyses. This study opens avenues for novel tissue-engineering strategies where precise control over vascularization and nerve growth is crucial. Conclusion. A groundbreaking dual approach, simultaneously targeting angiogenesis and innervation, addresses the necrotic bone in MRONJ syndrome. Vascularization and nerve formation play pivotal roles in driving reparative elements for bone regeneration. The scaffold achieves effective time/space control over necrotic bone regeneration. The authors are grateful for funding from the Spanish Government (PID2020-118669RA-I00)

Introduction. Bereft of their optimal tissue context, cells lose their phenotype, function and therapeutic potential during in vitro culture. Despite the fact that in vivo cells are exposed simultaneously to multiple signals, traditional ex vivo cultures are monofactorial. With these in mind, herein we assessed the combined effect of surface topography, substrate rigidity, collagen type I coating and macromolecular crowding in human tenocyte, skin fibroblast and bone marrow mesenchymal stromal cell cultures. Methods. Thermal imprinted was used to pattern (groove depth: 2,000 nm, groove width: 2,000 nm, line width: 2,000 nm) polydimethylsiloxane substrates of different rigidity (50 kPa, 130 kPa, 1,000 kPa). Grooved and planar substrates were subsequently coated with collagen type I and used to culture the aforementioned cell populations without and with macromolecular crowding (100 μg/ml carrageenan). After 3, 7 and 14 days in culture, cell morphology, viability, metabolic activity, proliferation, protein synthesis and deposition and gene expression analyses were conducted. Results. None of the variables assessed affected cell viability, metabolic activity and proliferation. Surface topography was found to be a potent regulator of cell morphology. Macromolecular crowding significantly increased extracellular matrix deposition, albeit in globular manner independently on whether grooved or planar substrates were used, possibly due to the low dimensionality of the grooves. Gene expression analysis made apparent that the 130 kPa and the 1,000 kPa grooved substrates under macromolecular crowding conditions maintained human tenocyte phenotype and directed human bone marrow mesenchymal stromal cells towards tendon-like lineage, respectively. None of the conditions assessed dramatically affected human skin fibroblast fate. Conclusions. Collectively, our data indicate that the physicochemical in vitro microenvironment modulators assessed herein are capable of maintaining human tenocyte phenotype and differentiating human bone marrow mesenchymal stromal cells towards tenogenic lineage, but not in trans-differentiating human skin fibroblasts

Introduction. Intervertebral disc degeneration (IDD) is a progressive process affecting all disc tissues, namely the nucleus pulposus (NP), annulus fibrosus (AF), and cartilaginous endplates (CEPs). Several cell-based therapies have been proposed to replenish the disc cell population and promote tissue regeneration. However, cell-free therapeutics have been increasingly explored due to potentially higher advantages and cost-effectiveness compared to cell transplantation. Recently, extracellular vesicles (EVs) isolated from healthy Tie2. +. -NP cells (NPCs) have shown promising regenerative outcomes on degenerative NPCs (dNPCs). The aim of this study was to assess the effect of such EVs on all disc cell types, including AF cells (AFCs) and CEP cells (CEPCs), compared to EVs isolated from bone-marrow derived mesenchymal stromal cells (BM-MSCs). Method. NPCs harvested from young donors underwent an optimized culture protocol to maximize Tie2 expression (NPCs. Tie2+. ). BM-MSCs were retrieved from a commercial cell line or harvested during spine surgery procedures. EV characterization was performed via particle size analysis (qNano), expression of EV markers (Western blot), and transmission electron microscopy. dNPCs, AFCs, and CEPCs were isolated from surgical specimens of patients affected by IDD, culture-expanded, and treated with NPCs. Tie2+. -EVs or BM-MSC-EVs ± 10 ng/mL IL-1b. EV uptake was assessed with PKH26 staining of EVs under confocal microscopy. Cell proliferation and viability were assessed with the CCK-8 assay. Result. Upon characterization, isolated EVs exhibited the typical exosomal characteristics. NPCs. Tie2+. -EVs and BM-MSC-EVs uptake was successfully observed in all dNPCs, AFCs, and CEPCs. Both EV products significantly increased dNPC, AFC, and CEPC viability, especially in samples treated with NPCs. Tie2+. -EVs. Conclusion. NPCs. Tie2+. -EVs demonstrated to significantly stimulate the proliferation and viability of degenerative cells isolated from all disc tissues. Rather than the sole NP, EVs isolated by committed progenitors physiologically residing within the disc may exert their regenerative effects on the whole organ, thus possibly constituting the basis for a new therapy for IDD

Introduction. Endochondral ossification (EO) is the process of bone development via a cartilage template. It involves multiple stages, including chondrogenesis, mineralisation and angiogenesis. Importantly, how cartilage mineralisation affects angiogenesis during EO is not fully understood. Here we aimed to develop a new in vitro co-culture model to recapitulate and study the interaction between mineralised cartilage generated from human mesenchymal stromal cells (hMSCs) and microvascular networks. Method. Chondrogenic hMSC pellets were generated by culture with transforming growth factor (TGF)-β3. For mineralised pellets, β-glycerophosphate (BGP) was added from day 7 and TGF-β3 was withdrawn on day 14. Conditioned medium (CM) from the pellets was used to evaluate the effect on human umbilical vein endothelial cells (HUVECs) in migration, proliferation and tube formation assays. To perform direct co-cultures, pellets were embedded in fibrin hydrogels containing vessel-forming cells (HUVECs, adipose stromal cells) for 10 days with BGP to induce mineralisation. The pellets and hydrogels were characterised by immunohistochemistry and confocal imaging. Result. The CM from d14 chondrogenic or mineralised pellets significantly stimulated HUVEC migration and proliferation, as well as in vitro vascular network formation. When CM from pellets subjected to prolonged mineralisation (d28) was used, these effects were strongly reduced. When chondrogenic and mineralised pellets were directly co-cultured with vessel-forming cells in fibrin hydrogels, the cartilage matrix (collagen type II/X stainings) and the mineral deposition (von Kossa staining) were well preserved. Confocal imaging analyses demonstrated the formation of microvascular networks with well-formed lumina. Importantly, more microvascular structures were formed in the proximity of chondrogenic pellets than mineralized pellets. Conclusion. The angiogenic properties of tissue engineered cartilage are significantly reduced upon prolonged mineralisation. We developed a 3D co-culture model to study the role of angiogenesis in endochondral bone formation, which can have applications in disease modelling studies

Aims

This study aimed to define the histopathology of degenerated humeral head cartilage and synovial inflammation of the glenohumeral joint in patients with omarthrosis (OmA) and cuff tear arthropathy (CTA). Additionally, the potential of immunohistochemical tissue biomarkers in reflecting the degeneration status of humeral head cartilage was evaluated.

Aims

This study examined the relationship between obesity (OB) and osteoporosis (OP), aiming to identify shared genetic markers and molecular mechanisms to facilitate the development of therapies that target both conditions simultaneously.