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Bone & Joint Research
Vol. 13, Issue 12 | Pages 779 - 789
16 Dec 2024
Zou H Hu F Wu X Xu B Shang G An D Qin D Zhang X Yang A

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. Methods. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) and western blotting were performed to analyze LINC01089, miR-1287-5p, and heat shock protein family A (HSP70) member 4 (HSPA4) expression. The osteogenic differentiation of MSCs was assessed through alkaline phosphatase (ALP) activity, alizarin red S (ARS) staining, and by measuring the levels of osteogenic gene marker expressions using commercial kits and RT-qPCR analysis. Cell proliferative capacity was evaluated via the Cell Counting Kit-8 (CCK-8) assay. The binding of miR-1287-5p with LINC01089 and HSPA4 was verified by performing dual-luciferase reporter and RNA immunoprecipitation (RIP) experiments. Results. LINC01089 expression was reinforced in serum samples of OP patients, but it gradually diminished while hMSCs underwent osteogenic differentiation. LINC01089 knockdown facilitated hMSC osteogenic differentiation. This was substantiated by: the increase in ALP activity; ALP, runt-related transcription factor 2 (RUNX2), osteocalcin (OCN), and osteopontin (OPN) messenger RNA (mRNA) levels; and level of ARS staining. Meanwhile, LINC01089 upregulation resulted in the opposite effects. LINC01089 targeted miR-1287-5p, and the LINC01089 knockdown-induced hMSC osteogenic differentiation was repressed by miR-1287-5p depletion. HSPA4 is a downstream function molecule of the LINC01089/miR-1287-5p pathway; miR-1287-5p negatively modulated HSPA4 levels and attenuated its functional effects. Conclusion. LINC01089 negatively regulated hMSC osteogenic differentiation, at least in part, via governing miR-1287-5p/HSPA4 signalling. These findings provide new insights into hMSC osteogenesis and bone metabolism. Cite this article: Bone Joint Res 2024;13(12):779–789


Bone & Joint Research
Vol. 13, Issue 12 | Pages 764 - 778
12 Dec 2024
Huang Q Zhuo Y Duan Z Long Y Wang J Zhang Z Fan S Huang Y Deng K Xin H

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.


Bone & Joint Research
Vol. 13, Issue 12 | Pages 725 - 740
5 Dec 2024
Xing J Liu S

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.


Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_18 | Pages 72 - 72
14 Nov 2024
Uvebrant K Andersen C Lim HC Vonk L Åkerlund EL
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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


Bone & Joint Research
Vol. 13, Issue 9 | Pages 462 - 473
6 Sep 2024
Murayama M Chow SK Lee ML Young B Ergul YS Shinohara I Susuki Y Toya M Gao Q Goodman SB

Bone regeneration and repair are crucial to ambulation and quality of life. Factors such as poor general health, serious medical comorbidities, chronic inflammation, and ageing can lead to delayed healing and nonunion of fractures, and persistent bone defects. Bioengineering strategies to heal bone often involve grafting of autologous bone marrow aspirate concentrate (BMAC) or mesenchymal stem cells (MSCs) with biocompatible scaffolds. While BMAC shows promise, variability in its efficacy exists due to discrepancies in MSC concentration and robustness, and immune cell composition. Understanding the mechanisms by which macrophages and lymphocytes – the main cellular components in BMAC – interact with MSCs could suggest novel strategies to enhance bone healing. Macrophages are polarized into pro-inflammatory (M1) or anti-inflammatory (M2) phenotypes, and influence cell metabolism and tissue regeneration via the secretion of cytokines and other factors. T cells, especially helper T1 (Th1) and Th17, promote inflammation and osteoclastogenesis, whereas Th2 and regulatory T (Treg) cells have anti-inflammatory pro-reconstructive effects, thereby supporting osteogenesis. Crosstalk among macrophages, T cells, and MSCs affects the bone microenvironment and regulates the local immune response. Manipulating the proportion and interactions of these cells presents an opportunity to alter the local regenerative capacity of bone, which potentially could enhance clinical outcomes. Cite this article: Bone Joint Res 2024;13(9):462–473


The Bone & Joint Journal
Vol. 106-B, Issue 9 | Pages 978 - 985
1 Sep 2024
Savoie III FH Delvadia BP Tate JP Winter JE Williams GH Sherman WF O’Brien MJ

Rotator cuff tears are common in middle-aged and elderly patients. Despite advances in the surgical repair of rotator cuff tears, the rates of recurrent tear remain high. This may be due to the complexity of the tendons of the rotator cuff, which contributes to an inherently hostile healing environment. During the past 20 years, there has been an increased interest in the use of biologics to complement the healing environment in the shoulder, in order to improve rotator cuff healing and reduce the rate of recurrent tears. The aim of this review is to provide a summary of the current evidence for the use of forms of biological augmentation when repairing rotator cuff tears.

Cite this article: Bone Joint J 2024;106-B(9):978–985.


Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_11 | Pages 4 - 4
4 Jun 2024
Stewart S Darwood A Higgins C Masouros S Ramasamy A
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Introduction. Fusion represents an effective treatment option in patients affected by end-stage arthritis. To minimise the risk of non-union following fusion, biological preparations such as bone marrow aspirate concentrate (BMAC) are commonly used intra-operatively. Mechanotransduction represents an emerging field of research whereby physical stimuli can be used to modulate the behaviour and differentiation of cells. Blast waves (a subtype of shock waves) are one such physical stimulus. The aim of this study was to investigate whether the osteogenic potential of BMAC can be enhanced using a blast wave, and thus improve its efficacy in fusion surgery. Methods. Human BMAC samples were obtained from three healthy patients and exposed to a single blast wave (peak overpressure= 50psi), before being placed in a suspension of mesenchymal stem cells, to represent the biological environment of the fusion site. Three test groups were used: MSC (the experimental control); MSC + BMAC; MSC + BMAC + blast wave. Calcium mineralisation assays were performed on the MSCs on Day 7 and 14 to assess for osteoblastic transformation. Results. Calcium mineralisation on Day 7 was significantly increased in the MSC + BMAC group compared to the MSC group (mean percentage change 42.12 vs 0.0, p=0.012). The MSC + BMAC + blast wave group also demonstrated significantly increased levels compared to the MSC + BMAC group (84.56 vs. 42.14, p = 0.039). The difference in calcium mineralisation between the MSC and MSC + BMAC + blast wave groups was strongly significant (0.00 vs. 84.56, p = 0.003). Conclusion. Exposure of BMAC to a single blast wave enhances its osteogenic potential. This represents a potential novel way to improve healing following fusion surgery and reduce the rates of non-union


Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_1 | Pages 88 - 88
2 Jan 2024
Kim M Kim, K
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There is still no consensus on which concentration of mesenchymal stem cells (MSCs) to use for promoting fracture healing in a rat model of long bone fracture. To assess the optimal concentration of MSCs for promoting fracture healing in a rat model. Wistar rats were divided into four groups according to MSC concentrations: Normal saline (C), 2.5 × 106 (L), 5.0 × 106 (M), and 10.0 × 106 (H) groups. The MSCs were injected directly into the fracture site. The rats were sacrificed at 2 and 6 자 post-fracture. New bone formation [bone volume (BV) and percentage BV (PBV)] was evaluated using micro-computed tomography (CT). Histological analysis was performed to evaluate fracture healing score. The protein expression of factors related to MSC migration [stromal cell-derived factor 1 (SDF-1), transforming growth factor-beta 1 (TGF-β1)] and angiogenesis [vascular endothelial growth factor (VEGF)] was evaluated using western blot analysis. The expression of cytokines associated with osteogenesis [bone morphogenetic protein-2 (BMP-2), TGF-β1 and VEGF] was evaluated using real-time polymerase chain reaction. Micro-CT showed that BV and PBV was significantly increased in groups M and H compared to that in group C at 6 wk post-fracture (P = 0.040, P = 0.009; P = 0.004, P = 0.001, respectively). Significantly more cartilaginous tissue and immature bone were formed in groups M and H than in group C at 2 and 6 wk post-fracture (P = 0.018, P = 0.010; P = 0.032, P = 0.050, respectively). At 2 wk post fracture, SDF-1, TGF-β1 and VEGF expression were significantly higher in groups M and H than in group L (P = 0.031, P = 0.014; P < 0.001, P < 0.001; P = 0.025, P < 0.001, respectively). BMP-2 and VEGF expression were significantly higher in groups M and H than in group C at 6 wk postfracture (P = 0.037, P = 0.038; P = 0.021, P = 0.010). Compared to group L, TGF-β1 expression was significantly higher in groups H (P = 0.016). There were no significant differences in expression levels of chemokines related to MSC migration, angiogenesis and cytokines associated with osteogenesis between M and H groups at 2 and 6 wk post-fracture. The administration of at least 5.0 × 106 MSCs was optimal to promote fracture healing in a rat model of long bone fractures


Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_2 | Pages 50 - 50
2 Jan 2024
Teixeira G
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Back pain is a leading cause of disability worldwide and it is primarily considered to be triggered by intervertebral disc (IVD) degeneration (IVDD). Current treatments may improve pain and mobility, but carry high costs and fail to address IVD repair or regeneration. As no effective therapeutic approach has been proposed to restore inflamed and degenerated IVDs, there is the urgent need to clarify the key pathomechanism of IVDD, the involvement of inflammation, particularly complement activation in matrix catabolism, and how to target them towards tissue repair/regeneration. Mesenchymal stem cell (MSC)-based therapies have become the focus of several regenerative IVD studies. Although patients in clinical trials reported less pain after cell therapy, the long-term success of cell engraftment is unclear due to the hostile IVD environment. The mechanism-of-action of MSCs is mostly dependent on the secreted soluble factors. Moreover, priming of MSC with interleukin (IL)-1β modulates the secretome content, improving its anti-inflammatory and regenerative effect on IVDD organ culture models. MSC-derived extracellular vesicles (EVs) have also been shown to modulate human IVD cells towards a healthy IVD phenotype in vitro. However, the mechanisms involved in the effect of secretome and EVs, particularly with regard to immunomodulation and matrix metabolism, are not fully understood. Our work investigates the effects of secretome and EVs secreted by IL-1β-primed MSCs to impair IVD matrix degradation and/or improve matrix formation in IVDD


Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_1 | Pages 95 - 95
2 Jan 2024
Gjerde C
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The aim of the ongoing projects was to demonstrate the efficacy of autologous bone marrow derived stem cells (MSC) combined with biomaterial to induced new bone formation in a randomized multicenter controlled clinical trial. Patients with a need for bone reconstruction of residual edentulous ridges in both the mandible and maxilla due to bone defects with a vertical loss of alveolar bone volume and/or knife edge ridges (≤ than 4,5 mm) unable to provide adequate primary stabilization for dental implants were included in the clinical study. Autologous bone marrow MSC were expanded, loaded on BCP and used to augment the alveolar ridges. After five months bone biopsies were harvested at the implant position site and implants were installed in the regenerated bone. The implants were loaded after 8–12 weeks. Safety, efficacy, quality of life and success/survival were assessed. Five clinical centers, 4 different countries participated. Bone grafts harvested from the ramus of the mandibles were used as control in the projects


Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_1 | Pages 103 - 103
2 Jan 2024
Vadalá G
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The use of mesenchymal stem cell (MSCs) for intervertebral disc (IVD) regeneration has been extensively explored in the last two decades. MSCs are potent cell types that can be easily and safely harvested due to their abundancy and availability. Moreover, they are characterized by the capacity to differentiate towards IVD cells as well as release growth factors to support resident cell metabolism and recruit local progenitor cells to induce endogenous repair of degenerated IVDs. This talk will outline the characteristics of the main MSC sources and their effect towards IVD regeneration based on available preclinical and clinical evidence. In addition, innovative aspects of MSC-derived cell-free therapies will also be discussed


Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_1 | Pages 27 - 27
2 Jan 2024
Smith RK
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Stem cells represent an exciting biological therapy for the management of many musculoskeletal tissues that suffer degenerative disease and/or where the reparative process results in non-functional tissue (‘failed healing’). The original hypothesis was that implanted cells would differentiate into the target tissue cell type and synthesise new matrix. However, this has been little evidence that this happens in live animals compared to the laboratory, and more recent theories have focussed on the immunomodulatory effects via the release of paracrine factors that can still improve the outcome, especially since inflammation is now considered one of the central processes that drive poor tendon healing. Because of the initial ‘soft’ regulatory environment for the use of stem cells in domestic mammals, bone and fat-derived stem cells quickly established themselves as a useful treatment for naturally occurring musculoskeletal diseases in the horse more than 20 years ago (Smith, Korda et al. 2003). Since the tendinopathy in the horse has many similarities to human tendinopathy, we propose that the following challenges and, the lessons learnt, in this journey are highly relevant to the development of stem cells therapies for human tendinopathy:. Source – while MSCs can be recovered from many tissues, the predominant sources for autologous MSCs have been bone and fat. Other sources, including blood, amnion, synovium, and dental pulp have also been commercialised for allogenic treatments. Preparation – ex vivo culture requires transport from a licensed laboratory while ‘minimally manipulated’ preparations can be prepared patient-side. Cells also need a vehicle for transport and implantation. Delivery – transport of cells from the laboratory to the clinic for autologous ex vivo culture techniques; implantation technique (usually by ultrasound-guided injection to minimise damage to the cells (or, more rarely, incorporated into a scaffold). They can also be delivered by regional perfusion via venous or arterial routes. Retention – relatively poor although small numbers of cells do survive for at least 5 months. Immediate loss to the lungs if the cells are administered via vascular routes. Synovially administered cells do not engraft into tendon. Adverse effects – very safe although needle tracts often visible (but do not seen to adversely affect the outcome). Allogenic cells require careful characterisation for MHC Class II antigens to avoid anaphylaxis or reduced efficacy. Appropriate injuries to treat – requires a contained lesion when administered via intra-lesional injection. Intrasynovial tendon lesions are more often associated with surface defects and are therefore less appropriate for treatment. Earlier treatment appears to be more effective than delayed, when implantation by injection is more challenging. Efficacy - beneficial effects shown at both tissue and whole animal (clinical outcome) level in naturally-occurring equine tendinopathy using bone marrow-derived autologous MSCs Recent (licenced) allogenic MSC treatment has shown equivalent efficacy while intra-synovial administration of MSCs is ineffective for open intra-synovial tendon lesions. Regulatory hurdles – these have been lighter for veterinary treatments which has facilitated their development. There has been greater regulation of commercial allogenic MSC preparations which have required EMA marketing authorisation


Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_1 | Pages 34 - 34
2 Jan 2024
Karoichan A Tabrizian M
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Mesenchymal stem cells-derived extracellular vesicles (MSC-EVs) have great promise in the field of orthopaedic nanomedicine due to their regenerative, as well as immunomodulatory and anti-inflammatory properties. Researchers are interested in harnessing these biologically sourced nanovesicles as powerful therapeutic tools with intrinsic bioactivity to help treat various orthopaedic diseases and defects. Recently, a new class of EV mimetics has emerged known as nanoghosts (NGs). These vesicles are derived from the plasma membrane of ghost cells, thus inheriting the surface functionalities and characteristics of the parent cell while at the same time allowing for a more standardized and reproducible production and significantly greater yield when compared to EVs. This study aims to investigate and compare the osteoinductive potential of MSC-EVs and MSC-NGs in vitro as novel tools in the field of bone tissue engineering and nanomedicine. To carry out this investigation, MSC-EVs were isolated from serum-free MSC conditioned media through differential ultracentrifugation. The remaining cells were treated with hypotonic buffer to produce MSC-ghosts that were then homogenized and serially extruded through 400 and 200 nm polycarbonate membranes to form the MSC-NGs. The concentration, size distribution, zeta potential, and protein content of the isolated nanoparticles were assessed. Afterwards, MSCs were treated with either MSC-EVs or MSC-NGs under osteogenic conditions, and their differentiation was assessed through secreted ALP assay, qPCR, and Alizarin Red mineralization staining. Isolation of MSC-EVs and MSC-NGs was successful, with relatively similar mean diameter size and colloidal stability. No effect on MSC viability and metabolic activity was observed with either treatment. Both MSC-EV and MSC-NG groups had enhanced osteogenic outcomes compared to the control; however, a trend was observed that suggests MSC-NGs as better osteoinductive mediators compared to MSC-EVs. Acknowledgements: The authors would like to acknowledge Canada Research Chair – Tier 1 in Regenerative Medicine and Nanomedicine, CHRP, and McGill's Faculty of Dental Medicine and Oral Health Sciences for their financial support


Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_1 | Pages 87 - 87
2 Jan 2024
Vargel I Açil M Tuncel S Baysal N Hartuç I Okur H Korkusuz F
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Deriving autologous mesenchymal stem cells (MSCs) from adipose tissues without using enzymes requires sophisticated biomedical instruments. Applied pressure on tissues and cells are adjusted manually although centrifugation and filtration systems are frequently used. The number of derived MSCs therefore could differ between instruments. We compared the number of MSCs obtained from four commercially available devices and our newly designed and produced instrument (A2, B3, L3, M2 and T3). Three-hundred mL of adipose tissue was obtained from a female patient undergoing liposuction using the transillumination solution. Obtained tissue was equally distributed to each device and handled according to the producers' guides. After handling, 3 mL stromal vascular fraction (SVF) was obtained from each device. Freshly isolated SVF was characterized using multi-color flow cytometry (Navios Flow Cytometer, Beckman Coulter, USA). Cell surface antigens were chosen according to IFATS and ISCT. CD31-FITC, CD34-PC5,5, CD73-PE, CD90-PB and CD45-A750 (Backman Coulter, USA) fluorochrome-labeled monoclonal antibodies were assessed. Markers were combined with ViaKrome (Beckman Coulter, USA) to determine cell viability. At least 10. 5. cells were acquired from each sample. A software (Navios EX, Beckman Coulter, USA) was used to create dot plots and to calculate the cell composition percentages. The data was analyzed in the Kaluza 2.1 software package (Beckman Coulter, USA). Graphs were prepared in GraphPad Prism. CD105 PC7/CD31 FITC cell percentages were 23,9%, 13,5%, 24,6%, 11,4% and 28,8% for the A2, B3, L3, M2 and T3 devices, respectively. We conclude that the isolated MSC percentage ranged from 11,4% to 28,8% between devices. The number of MSCs in SVF are key determinants of success in orthobiological treatments. Developing a device should focus on increasing the number of MSCs in the SVF while preserving its metabolic activity. Acknowledgments: Scientific and Technological Research Council of Türkiye (TÜBİTAK)- Technology and Innovation Funding Program Directorate (TEYDEB) funded this project (#321893). Servet Kürümoğlu and Bariscan Önder of Disposet Ltd., Ankara, Türkiye (. www.disposet.com. ) contributed to the industrial design and research studies. Ali Tuncel and Feza Korkusuz are members of the Turkish Academy of Sciences (TÜBA). Nilsu Baysal was funded by the STAR Program of TÜBITAK Grant # 3210893


Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_1 | Pages 129 - 129
2 Jan 2024
Doyle S Winrow D Aregbesola T Martin J Pernevik E Kuzmenko V Howard L Thompson K Johnson M Coleman C
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In 2021 the bone grafting market was worth €2.72 billion globally. As allograft bone has a limited supply and risk of disease transmission, the demand for synthetic grafting substitutes (BGS) continues to grow while allograft bone grafts steadily decrease. Synthetic BGS are low in mechanical strength and bioactivity, inspiring the development of novel grafting materials, a traditionally laborious and expensive process. Here a novel BGS derived from sustainably grown coral was evaluated. Coral-derived scaffolds are a natural calcium carbonate bio-ceramic, which induces osteogenesis in bone marrow mesenchymal stem cells (MSCs), the cells responsible for maintaining bone homeostasis and orchestrating fracture repair. By 3D printing MSCs in coral-laden bioinks we utilise high throughput (HT) fabrication and evaluation of osteogenesis, overcoming the limitations of traditional screening methods. MSC and coral-laden GelXA (CELLINK) bioinks were 3D printed in square bottom 96 well plates using a CELLINK BIO X printer with pneumatic adapter Samples were non-destructively monitored during the culture period, evaluating both the sample and the culture media for metabolism (PrestoBlue), cytotoxicity (lactose dehydrogenase (LDH)) and osteogenic differentiation (alkaline phosphatase (ALP)). Endpoint, destructive assays used included qRT-PCR and SEM imaging. The inclusion of coral in the printed bioink was biocompatable with the MSCs, as reflected by maintained metabolism and low LDH release. The inclusion of coral induced osteogenic differentiation in the MSCs as seen by ALP secretion and increased RUNX2, collagen I and osteocalcin transcription. Sustainably grown coral was successfully incorporated into bioinks, reproducibly 3D printed, non-destructively monitored throughout culture and induced osteogenic differentiation in MSCs. This HT fabrication and monitoring workflow offers a faster, less labour-intensive system for the translation of bone substitute materials to clinic. Acknowledgements: This work was co-funded by Enterprise Ireland and Zoan Biomed through Innovation Partnership IP20221024


Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_2 | Pages 135 - 135
2 Jan 2024
Füllemann P Jörimann T Bella E Stoddart M Matthys R Verrier S
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Bone healing outcome is highly dependent on the initial mechanical fracture environment [1]. In vivo, direct bone healing requires absolute stability and an interfragmentary strain (IFS) below 2% [2]. In the majority of cases, however, endochondral ossification is engaged where frequency and amplitude of IFS are key factors. Still, at the cellular level, the influence of those parameters remains unknown. Understanding the regulation of naïve hMSC differentiation is essential for developing effective bone healing strategies. Human bone-marrow-derived MSC (KEK-ZH-NR: 2010–0444/0) were embedded in 8% gelatin methacryol. Samples (5mm Ø x 4mm) were subjected to 0, 10 and 30% compressive strain (5sec compression, 2hrs pause sequence for 14 days) using a multi-well uniaxial bioreactor (RISystem) and in presence of chondro-permissive medium (CP, DMEM HG, 1% NEAA, 10 µM ITS, 50 µg/mL ascorbic acid, and 100 mM Dex). Cell differentiation was assessed by qRT-PCR and histo-/immunohistology staining. Experiments were repeated 5 times with cells from 5 donors in duplicate. ANOVA with Tukey post-hoc correction or Kurskal-Wallis test with Dunn's correction was used. Data showed a strong upregulation of hypertrophic related genes COMP, MMP13 and Type 10 collagen upon stimulation when compared to chondrogenic SOX9, ACAN, Type 2 collagen or to osteoblastic related genes Type 1 Collagen, Runx2. When compared to chondrogenic control medium, cells in CP with or without stimulation showed low proteoglycan synthesis as shown by Safranine-O-green staining. In addition, the cells were significantly larger in 10% and 30% strain compared to control medium with 0% strain. Type 1 and 10 collagens immunostaining showed stronger Coll 10 expression in the samples subjected to strain compared to control. Uniaxial deformation seems to mainly promote hypertrophic-like chondrocyte differentiation of MSC. Osteogenic or potentially late hypertrophic related genes are also induced by strain. Acknowledgments: Funded by the AO Foundation, StrainBot sponsored by RISystemAG & PERRENS 101 GmbH


Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_1 | Pages 5 - 5
2 Jan 2024
Karaçoban L Gizer M Fidan BB Kaplan O Çelebier M Korkusuz P Turhan E Korkusuz F
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Osteoarthritis (OA) is a disabling disease depriving the quality of life of patients. Mesenchymal stem cells (MSCs) are recently used to modify the inflammatory and degenerative cascade of the disease. Source of MSCs could change the progression and symptoms of OA due to their different metabolomic activities. We asked whether MSCs derived from the infrapatellar fat (IPF), synovium (Sy) and subcutaneous (SC) tissues will decrease inflammatory and degenerative markers of normal and OA chondrocytes and improve regeneration in culture. Tissues were obtained from three male patients undergoing arthroscopic knee surgery due to sports injuries after ethical board approval. TNFa concentration decreased in all MSC groups (Sy=156,6±79, SC=42,1±6 and IPF=35,5±3 pg/ml; p=0,036) on day 14 in culture. On day seven (Sy=87,4±43,7, SC=23±8,9 and IPF=14,7±3,3 pg/ml, p=0,043) and 14 (Sy=29,1±11,2, SC=28,3±18,5 and IPF=20,3±16,2 pg/ml, p=0,043), MMP3 concentration decreased in all groups. COMP concentration changes however were not significant. Plot scores of tissues for PC2-13,4% were significantly different. Based on the results of liquid chromatography-mass spectrometry (LC-MS) metabolomics coupled with recent data processing strategies, clinically relevant seven metabolites (L-fructose, a-tocotrienol, coproporphyrin, nicotinamide, bilirubin, tauro-deoxycholic acid and galactose-sphingosine) were found statistically different (p<0.05 and fold change>1.5) ratios in tissue samples. Focusing on these metabolites as potential therapeutics could enhance MSC therapies. Acknowledgment: Hacettepe University, Scientific Research Projects Coordination Unit (#THD-2020-18692) and Turkish Society of Orthopedics and Traumatology (#TOTBID-89) funded this project. Feza Korkusuz MD is a member of the Turkish Academy of Sciences (TÜBA)


Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_1 | Pages 144 - 144
2 Jan 2024
Anghileri G DeVoogt W Seinen C Peacock B Vader P Martin-Fabiani I Davies O
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Matrix-bound vesicles (MBVs) are embedded within osteoid and function as the site of initial mineral formation. However, they remain insufficiently characterised in terms of biogenesis, composition and function while their relationship with secreted culture medium EVs (sEVs) such as exosomes remains debated. We aimed to define the biogenesis and pro-mineralisation capacity of MBVs and sEVs to understand their potential in regenerative orthopaedics. sEVs and MBVs isolated from conditioned medium (differential ultracentrifugation) and ECM (collagenase digestion and differential ultracentrifugation) of mineralising MC3T3 pre-osteoblast and human bone marrow MSC cultures were characterised by nanoparticle tracking analysis, western blotting, nano-flow cytometry, super resolution microscopy (ONI) and TEM. Immunoprecipitated populations positive for alkaline phosphatase (ALP), a putative marker of mineralisation capacity, were also characterised. Collagen binding efficiency was evaluated using MemGlow staining. Results reported were comparative across both cell lines. Western blots indicated MBV fractions were positive for markers of endosomal biogenesis (CD9, CD81, ALIX, TSG101) and pro-mineralising proteins (ALP, Pit1, Annexin II, Annexin V), with Annexin V and CD9 present in immunoprecipitated ALP-positive fractions. MBVs were significantly larger than sEVs (p<0.05) and contained a higher amount of ALP (p<0.05) with a significant increase from day 7 to day 14 of cellular mineralisation (p<0.05). This mirrored the pattern of electron-dense vesicles seen via TEM. Super resolution single vesicle analysis revealed for the first-time co-expression of ALP with markers of endosomal biogenesis (CD9, CD63, CD81, ALIX) and Annexin II in both vesicle types, with higher co-expression percentage in MBVs than sEVs. MBVs also exhibited preferential collagen binding. Advanced imaging methods demonstrated that contrary to opinions in the field, MBVs appear to possess exosomal markers and may arise via endosomal biogenesis. However, it was evident that a higher proportion of MBVs possessed machinery to induce mineralisation and were enriched in mineral-dense material


Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_1 | Pages 126 - 126
2 Jan 2024
Schmidt S Klampfleuthner F Diederichs S
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The signaling molecule prostaglandin E2 (PGE2), synthesized by cyclooxygenase-2 (COX-2), is immunoregulatory and reported to be essential for skeletal stem cell function. Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used in osteoarthritis (OA) analgesia, but cohort studies suggested that long-term use may accelerate pathology. Interestingly, OA chondrocytes secrete high amounts of PGE2. Mesenchymal stromal cell (MSC) chondrogenesis is an in vitro OA model that phenocopies PGE2 secretion along with a hypertrophic OA-like cell morphology. Our aim was to investigate cause and effects of PGE2 secretion in MSC-based cartilage neogenesis and hypertrophy and identify molecular mechanisms responsible for adverse effects in OA analgesia. Human bone marrow-derived MSCs were cultured in chondrogenic medium with TGFβ (10ng/mL) and treated with PGE2 (1µM), celecoxib (COX-2 inhibitor; 0.5µM), AH23848/AH6809 (PGE2 receptor antagonists; 10µM), or DMSO as a control (n=3–4). Assessment criteria were proteoglycan deposition (histology), chondrocyte/hypertrophy marker expression (qPCR), and ALP activity. PGE2 secretion was measured (ELISA) after TGFβ withdrawal (from day 21, n=2) or WNT inhibition (2µM IWP-2 from day 14; n=3). Strong decrease in PGE2 secretion upon TGFβ deprivation or WNT inhibition identified both pathways as PGE2 drivers. Homogeneous proteoglycan deposition and COL2A1 expression analysis showed that MSC chondrogenesis was not compromised by any treatment. Importantly, hypertrophy markers (COL10A1, ALPL, SPP1, IBSP) were significantly reduced by PGE2 treatment, but increased by all inhibitors. Additionally, PGE2 significantly decreased ALP activity (2.9-fold), whereas the inhibitors caused a significant increase (1.3-fold, 1.7-fold, 1.8-fold). This identified PGE2 as an important inhibitor of chondrocyte hypertrophy. Although TGFβ and WNT are known pro-arthritic signaling pathways, they appear to induce a PGE2-mediated antihypertrophic effect that can counteract pathological cell changes in chondrocytes. Hampering this rescue mechanism via COX inhibition using NSAIDs thus risks acceleration of OA progression, indicating the need of OA analgesia adjustment


Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_1 | Pages 96 - 96
2 Jan 2024
Al-Sharabi N
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Growing evidence has suggested that paracrine mechanisms of Mesenchymal stem cell (MSC) may be involved in the underlying mechanism of MSC after transplantation, and extracellular vesicles (EVs) are an important component of this paracrine role. The aim of this study was to investigate the in vitro osteogenic effects of EVs derived from undifferentiated mesenchymal stem cells and from chemically induced to differentiate into osteogenic cells for 7 days. Further, the osteoinductive potential of EVs for bone regeneration in rat calvarial defects was assessed. We could isolate and characterize EVs from naïve and osteogenic-induced MSCs. Proteomic analysis revealed that EVs contained distinct protein profiles, with Osteo-EVs having more differentially expressed proteins with osteogenic properties. EVs were found to enhance the proliferation and migration of cultured MSC. In addition, the study found that Osteo-EVs/MEM combination scaffolds could enhance greater bone formation after 4 weeks as compared to native MEM loaded with serum-free media. The study suggests that EVs derived from chemically osteogenic-induced MSCs for 7 days can significantly enhance both the osteogenic differentiation activity of cultured hMSCs and the osteoinductivity of MEM scaffolds. The results indicate that Osteo-MSC-secreted nanocarriers-EVs combined with MEM scaffolds can be used for repairing bone defects