Total Knee Arthroplasty (TKA) improves the quality of life of osteoarthritic and rheumatoid arthritis patients, however, is associated with moderate to severe postoperative pain. There are multiple methods of managing postoperative pain that include epidural anesthesia but it prevents early mobilization and results in postoperative hypotension and spinal infection. Controlling local pain pathways through intra-articular administration of analgesics is a novel method and is inexpensive and simple. Hence, we assess the effects of postoperative epidural bupivacaine injection along with intra-articular injection in total knee replacement patients. The methodology included 100 patients undergoing TKA randomly divided into two groups, one administered with only epidural bupivacaine injection and the other with intra-articular cocktail injection. The results were measured based on a 10-point pain assessment scale, knee's range of motion (ROM), and Lysholm knee score. The VAS score was lower in the intra-articular cocktail group compared to the bupivacaine injection group until the end of 1-week post-administration (p<0.01). Among inter-group comparisons, we observed that the range of motion was significantly more in cocktail injection as compared to the bupivacaine group till the end of one week (p<0.05). Lysholm's score was significantly more in cocktail injection as compared to the bupivacaine group till the end of one week (p<0.05). Our study showed that both epidural bupivacaine injection and intra-articular injection were effective in reducing pain after TKA and have a comparable functional outcome at the end of 4 weeks follow up. However, the pain relief was faster in cases with intra-articular injection, providing the opportunity for early rehabilitation. Thus, we recommend the use of intra-articular cocktail injection for postoperative management of pain after total knee arthroplasty, which enables early rehabilitation and faster functional recovery of these patients

Objectives. Recent studies have shown that systemic injection of rapamycin can prevent the development of osteoarthritis (OA)-like changes in human chondrocytes and reduce the severity of experimental OA. However, the systemic injection of rapamycin leads to many side effects. The purpose of this study was to determine the effects of intra-articular injection of Torin 1, which as a specific inhibitor of mTOR which can cause induction of autophagy, is similar to rapamycin, on articular cartilage degeneration in a rabbit osteoarthritis model and to investigate the mechanism of Torin 1’s effects on experimental OA. Methods. Collagenase (type II) was injected twice into both knees of three-month-old rabbits to induce OA, combined with two intra–articular injections of Torin 1 (400 nM). Degeneration of articular cartilage was evaluated by histology using the Mankin scoring system at eight weeks after injection. Chondrocyte degeneration and autophagosomes were observed by transmission electron microscopy. Matrix metallopeptidase-13 (MMP-13) and vascular endothelial growth factor (VEGF) expression were analysed by quantitative RT-PCR (qPCR).Beclin-1 and light chain 3 (LC3) expression were examined by Western blotting. Results. Intra-articular injection of Torin 1 significantly reduced degeneration of the articular cartilage after induction of OA. Autophagosomes andBeclin-1 and LC3 expression were increased in the chondrocytes from Torin 1-treated rabbits. Torin 1 treatment also reduced MMP-13 and VEGF expression at eight weeks after collagenase injection. Conclusion. Our results demonstrate that intra-articular injection of Torin 1 reduces degeneration of articular cartilage in collagenase-induced OA, at least partially by autophagy activation, suggesting a novel therapeutic approach for preventing cartilage degeneration and treating OA. Cite this article: N-T. Cheng, A. Guo, Y-P. Cui. Intra-articular injection of Torin 1 reduces degeneration of articular cartilage in a rabbit osteoarthritis model. Bone Joint Res 2016;5:218–224. DOI: 10.1302/2046-3758.56.BJR-2015-0001

Intra-articular punctures and injections are performed routinely on patients with injuries to and chronic diseases of joints, to release an effusion or haemarthrosis, or to inject drugs. The purpose of this study was to investigate the accuracy of placement of the needle during this procedure. A total of 76 cadaver acromioclavicular joints were injected with a solution containing methyl blue and subsequently dissected to distinguish intra- from peri-articular injection. In order to assess the importance of experience in achieving accurate placement, half of the injections were performed by an inexperienced resident and half by a skilled specialist. The specialist injected a further 20 cadaver acromioclavicular joints with the aid of an image intensifier. The overall frequency of peri-articular injection was much higher than expected at 43% (33 of 76) overall, with 42% (16 of 38) by the specialist and 45% (17 of 38) by the resident. The specialist entered the joint in all 20 cases when using the image intensifier. Correct positioning of the needle in the joint should be facilitated by fluoroscopy, thereby guaranteeing an intra-articular injection

Osteoarthritis (OA) is a degenerative and inflammatory joint disease that affects the whole joint. Mesenchymal stem cells ability to secrete anti-inflammatory and immuno-modulatory factors represents an attractive tool in the treatment of OA. Considering the risk of cell leakage and the massive cell death upon intra-articular injection, we developed a micromolding protocol of encapsulation that allows to obtain particles that (i) could be injected with a 26G needle into a mouse joint and (ii) could provide a 3D microenvironment supporting cell biological activity. Polydimethylsiloxane (PDMS) chips containing circular micromolds were manufactured and a solution of alginate (2% w/v) containing human adipose stem cells (3 millions/mL) was deposited on the chips. Cell loading into the micromolds was performed either by sedimentation or by centrifugation. Following Ca2+ crosslinking, alginate particles (diameter 150±0.7μm) were obtained. The number of cells per particle was 5 times higher when the micromolds were loaded by centrifugation. Cell number and metabolic activity remained stable for 7 days after encapsulation and injection through a 26G needle had no impact on cell viability. When cells were stimulated with TNF-alpha and INF-gamma, prostaglandin E2 (PGE2) concentration in the supernatant was multiplied by 13 and 7 and indoleamine2,3-dioxygenase (IDO) activity was 2 and 4 times higher when cell loading was performed by sedimentation or centrifugation, respectively. We have demonstrated that encapsulated cells were able to sense and respond to an inflammatory stimulus and their therapeutic potential will be evaluated in a murine model of osteoarthritis

Introduction and Objective. Osteoarthritis (OA) is the most common inflammatory and degenerative joint disease. Mesenchymal Stromal Cells (MSCs), with their chondro-protective and immune-regulatory properties, have been considered as a new approach to treat OA. Considering the risk of cell leakage outside the articular space and the poor survival rate after intra-articular (IA) injection, we hypothesized that cell encapsulation in cytoprotective hydrogels could overcome these limitations and provide cells with a suitable 3D microenvironment supporting their biological activity. We previously generated micromolded alginate particles (diameter 150 μm) and demonstrated the long-term viability of microencapsulated MSCs isolated from human adipose tissue (hASCs). Encapsulated cells maintained their in vitro ability to sense and respond to a pro-inflammatory environment (IFN-γ/TNF-α or synovial fluids from OA patients) by secreting PGE. 2. , IDO, HGF and TGF-β. In this study, we evaluated the anti-OA efficacy of these microencapsulated hASCs in a post-traumatic OA model in rabbits. Materials and Methods. OA was surgically induced by anterior cruciate ligament transection (ACLT)-mediated destabilization of the right knee in rabbits (n=24). Eight weeks after surgery, destabilized joints were injected (IA, 26G needle) with 200 μL of either PBS, blank microparticles, non-encapsulated or microencapsulated cells (5×10. 5. cells). Six weeks after injection, rabbits were euthanized and all destabilized (right) and sham-operated (left contralateral) joints were dissected and analyzed for OA severity. Tibial subchondral bone histomorphometric parameters were measured by quantitative micro-computed tomography (micro-CT). Histological sections of samples were analyzed after Safranin-O staining and quantitatively assessed according to a modified Osteoarthritis Research Society International (OARSI) scoring system. Immunohistochemical detection of NITEGE was performed to assess the extracellular matrix degradation. Results. Micro-CT analysis of destabilized joints confirmed that the rabbit ACLT significantly affected the tibial subchondral bone architecture as early as eight weeks, as revealed by significant changes of the subchondral bone parameters of operated joints compared to the sham operated joints. In particular, destabilized joints exhibited a Bone Volume/Tissue Volume ratio (BV/TV) ranging from 53.4% to 56.6%, compared to a mean BV/TV of 65.4% for sham operated joints. All destabilized joints also exhibited a significantly increased modified OARSI score, ranging from 7.4±0.4 for those injected with encapsulated cells to 8.9±0.2 for those injected with PBS, as compared to 4.8±0.4 for sham-operated joints. Of interest, we identified a slight, while not significant, reduction of the severity of OA lesions after injection of microencapsulated cells using the modified OARSI scoring. Finally, semi-quantitative analysis of NITEGE immunostaining revealed a significant increase in all destabilized joints that were injected with PBS or blank microparticles, in comparison with sham ones. On the contrary, NITEGE immunostaining in destabilized joints that were injected with non-encapsulated or encapsulated hASC revealed a significant reduced NITEGE immunostaining, indicating a decreased matrix degradation. Conclusions. Our data suggest that the microencapsulated hASCs exerted their anti-OA properties after IA injection in rabbit knees, as evidenced by the tendency toward a reduced modified OARSI score, and most importantly a significant reduction in NITEGE immunostaining associated matrix degradation. Further studies are now warranted to investigate the anti-OA efficacy of microencapsulated hASCs in the long-term

Background

Carpometacarpal osteoarthritis is a degenerative disease of the hand that causes pain, stiffness and weakness. Currently, no drugs are available to prevent progression or cure this disease. Ultimately, the last treatment option is the surgical removal of the trapezium bone. In order to this limited treatment options, the utilization of autologous fat injections or adipose-derived stem progenitor cells (ADSPCs) provides a novel treatment option to inhibit the progression of this disease and potentially regenerate the damaged tissue.

Objective. To study the effect of hyaluronic acid (HA) on local anaesthetic chondrotoxicity in vitro. Methods. Chondrocytes were harvested from bovine femoral condyle cartilage and isolated using collagenase-containing media. At 24 hours after seeding 15 000 cells per well onto a 96-well plate, chondrocytes were treated with media (DMEM/F12 + ITS), PBS, 1:1 lidocaine (2%):PBS, 1:1 bupivacaine (0.5%):PBS, 1:1 lidocaine (2%):HA, 1:1 bupivacaine (0. 5%):HA, or 1:1 HA:PBS for one hour. Following treatment, groups had conditions removed and 24-hour incubation. Cell viability was assessed using PrestoBlue and confirmed visually using fluorescence microscopy. Results. Media-treated groups had a mean of 1.55×10. 4. cells/well (. sem. 783). All treated cells showed statistically significant reduced viability when compared with media alone (all p < 0.003). Cells treated with bupivacaine + HA (6.70×10. 3. cells/well (. sem. 1.10×10. 3. )) survived significantly more than bupivacaine (2.44×10. 3. cells/well (. sem . 830)) (p < 0.001). Lidocaine + HA (1.45×10. 3. cells/well (. sem. 596)) was not significantly more cytotoxic than lidocaine (2.24×10. 3. cells/well (. sem. 341)) (p = 0.999). There was no statistical difference between the chondrotoxicities of PBS (8.49×10. 3. cells/well (. sem. 730) cells/well) and HA (4.75×10. 3. cells/well (. sem. 886)) (p = 0.294). Conclusions. HA co-administration reduced anaesthetic cytotoxicity with bupivacaine but not lidocaine, suggesting different mechanisms of injury between the two. Co-administered intra-articular injections of HA with bupivacaine, but not lidocaine, may protect articular chondrocytes from local anaesthetic-associated death. Cite this article: Bone Joint Res 2013;2:270–5

Introduction and Objective

Total shoulder replacement is a common elective procedure offered to patients with end stage arthritis. While most patients experience significant pain relief and improved function within months of surgery, some remain unsatisfied because of residual pain or dissatisfaction with their functional status. Among these patients, when laboratory workup eliminates infection as a possibility, corticosteroid injection (CSI) into the joint space, or on the periprosthetic anatomic structures, is a common procedure used for symptom management. However, the efficacy and safety of this procedure has not been previously reported in shoulder literature.

Osteochondral injuries are a recognised factor in the development of osteoarthritis (OA). Mesenchymal stromal cells (MSCs) represent a promising biological therapeutic option as an OA-modifying treatment, and they also secrete factors that may have an anti-catabolic effect and/or encourage endogenous repair. We aim to study the effects of (i) intra-articular injection of human bone-marrow-derived MSCs and (ii) their secretome on recovery in a murine knee osteochondral injury model. The MSC secretome was generated by stimulating human bone-marrow-derived MSCs with tumour necrosis factor alpha (TNFα). Mice (n=48) were injected with i) MSC secretome, ii) MSCs or iii) cell culture medium (control). Pain was assessed by activity monitoring, and cartilage repair, subchondral bone volume and synovial inflammation were evaluated using histology and microCT. Both MSC- and MSC-secretome-injected mice showed significant pain reduction at day 7 when compared to control mice, but only the MSC-injected mice maintained a significant improvement over the controls at day 28. Cartilage repair was significantly improved in MSC-injected mice. No significant effects were observed with regards to synovial inflammation or subchondral bone volume. The MSC secretome demonstrates regenerative effects but this does not appear to be as sustained as a MSC cell therapy. Further studies are required to investigate if this can be overcome using different dosing regiments for injection of the MSC secretome. As we further understand the regenerative properties of the MSC secretome, we may be able to enhance the clinical translatability of these therapies. Direct intra-articular injection of MSCs for the treatment of OA also appears promising as a potential future strategy for OA management. Acknowledgements: MS is supported by a grant from the Wellcome Trust (PhD Programme for Clinicians)

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

TGF-β/Smad2 signaling is considered to be one of the important pathways involved in osteoarthritis (OA) and protein phosphatase magnesium-dependent 1A (PPM1A) functions as an exclusive phosphatase of Smad2 and regulates TGF-β signaling, here, we investigated the functional role of PPM1A in OA pathogenesis. PPM1A expressions in both human OA cartilage and experimental OA mice chondrocytes were analyzed immunohistochemically. Besides, the mRNA and protein expression of PPM1A induced by IL-1β treatment were also detected by q-PCR and immunofluorescence in vitro. OA was induced in PPM1A knockout (KO) mice by destabilization of the medial meniscus (DMM), and histopathological examination was performed. OA was also induced in wild-type (WT) mice, which were then treated with an intra-articular injection of a selective PPM1A inhibitor for 8 weeks. PPM1A protein expressions were increased in both human OA cartilage and experimental OA mice chondrocytes. We also found that treatment with IL-1β in mouse primary chondrocytes significantly increased both mRNA and protein expression of PPM1A in vitro. Importantly, our data showed that PPM1A deletion could substantially protect against surgically induced OA. Concretely, the average OARSI score and quantification of BV/TV of subchondral bone in KO mice were significantly lower than that in WT mice 8 weeks after DMM surgery. Besides, TUNEL staining revealed a significant decrease in apoptotic chondrocytes in PPM1A-KO mice with DMM operation. With OA induction, the rates of chondrocytes positive for Mmp-13 and Adamts-5 in KO mice were also significantly lower than those in WT mice. Moreover, compared with WT mice, the phosphorylation of Smad2 in chondrocytes was increased in KO mice underwent DMM surgery. However, articular-injection with SD-208, a selective inhibitor of TGF-β/Smad2 signaling could significantly abolish the chondroprotective phenotypes in PPM1A-KO mice. Additionally, both cartilage degeneration and subchondral bone subchondral bone sclerosis in DMM model were blunted following intra-articular injection with BC-21, a small-molecule inhibitor for PPM1A. Our study demonstrated that PPM1A inhibition attenuates OA by regulating TGF-β/Smad2 signaling. Furthermore, PPM1A is a potential target for OA treatment and BC-21 may be employed as alternative therapeutic agents for the management of OA

Objectives. Intra-articular injections of local anaesthetics (LA), glucocorticoids (GC), or hyaluronic acid (HA) are used to treat osteoarthritis (OA). Contrast agents (CA) are needed to prove successful intra-articular injection or aspiration, or to visualize articular structures dynamically during fluoroscopy. Tranexamic acid (TA) is used to control haemostasis and prevent excessive intra-articular bleeding. Despite their common usage, little is known about the cytotoxicity of common drugs injected into joints. Thus, the aim of our study was to investigate the effects of LA, GC, HA, CA, and TA on the viability of primary human chondrocytes and tenocytes in vitro. Methods. Human chondrocytes and tenocytes were cultured in a medium with three different drug dilutions (1:2; 1:10; 1:100). The following drugs were used to investigate cytotoxicity: lidocaine hydrochloride 1%; bupivacaine 0.5%; triamcinolone acetonide; dexamethasone 21-palmitate; TA; iodine contrast media; HA; and distilled water. Normal saline served as a control. After an incubation period of 24 hours, cell numbers and morphology were assessed. Results. Using LA or GC, especially triamcinolone acetonide, a dilution of 1:100 resulted in only a moderate reduction of viability, while a dilution of 1:10 showed significantly fewer cell counts. TA and CA reduced viability significantly at a dilution of 1:2. Higher dilutions did not affect viability. Notably, HA showed no effects of cytotoxicity in all drug dilutions. Conclusion. The toxicity of common intra-articular injectable drugs, assessed by cell viability, is mainly dependent on the dilution of the drug being tested. LA are particularly toxic, whereas HA did not affect cell viability. Cite this article: P. Busse, C. Vater, M. Stiehler, J. Nowotny, P. Kasten, H. Bretschneider, S. B. Goodman, M. Gelinsky, S. Zwingenberger. Cytotoxicity of drugs injected into joints in orthopaedics. Bone Joint Res 2019;8:41–48. DOI: 10.1302/2046-3758.82.BJR-2018-0099.R1

Intra-articular injections of human mesenchymal stromal cells (MSCs) and platelet-rich plasma (PRP) have been intensively investigated as therapies for knee osteoarthritis (OA) with positive outcomes. In this work we evaluated weather a combination of the treatments (MSCs + PRP) would be beneficial compared to MSCs alone (MSCs) and standard corticosteroid injection (Control group). Forty seven patients (24 males and 23 females; 53.3 ± 10.7 years old) with radiographic symptomatic knee OA (Dejour grades II–IV) were randomized to receive intra-articular injections of MSCs (n = 16), MSCs + PRP (n = 14) or corticosteroid (n=17). MSCs were obtained after mononuclear cells separation from bone marrow aspiration collected from both posterior iliac crests using Sepax automated closed system and expanded in culture until reaching the number of 4 × 10. 7. PRP was obtained by double-centrifugation of whole blood according to a protocol developed in house. After 12 months follow-up, the MSCs and MSCs+PRP groups achieved higher percentages of expected improvement when comparing to the corticosteroid group for the KOOS-symptoms, pain, function and daily living, domains and global score. For the population older or equal to 60 years old the MSCs+PRP group showed significant superiority for the KOOS-ADL domain at 12 months. Cytokines quantification evidenced anti-inflammatory aspects of the treatments. This work evidences the safety and efficacy of intra-articular injection of MSCs for the treatment of early knee OA, with greater improvement with PRP addition particularly to the older population

Osteoarthritis, the most common degenerative joint disease, significantly impairs life quality and labor capability of patients. Synovial inflammation, initiated by HMGB1 (High mobility group box 1)-induced activation of macrophage, precedes other pathological changes. As an upstream regulator of NF-κB (nuclear factor-kappa B) and MAPK (mitogen-activated protein kinase) signaling pathway, TAK1 (TGF-β activated kinase 1) participates in macrophage activation, while its function in osteoarthritis remains unveiled. This study aims to investigate the role of TAK1 in the pathogenesis of osteoarthritis via both in vitro and in vivo approaches. We performed immunohistochemical staining for TAK1 in synovial tissue, both in osteoarthritis patients and healthy control. Besides, immunofluorescence staining for F4/80 as macrophage marker and TAK1 were conducted as well. TAK1 expression was examined in RAW264.7 macrophages stimulated by HMGB1 via qPCR (Quantitative polymerase chain reaction) and Western blotting, and the effect of TAK1 inhibitor (5z-7 oxozeaenol) on TNF-α production was evaluated by immunofluorescence staining. Further, we explored the influence of intra-articular shRNA (short hairpin RNA) targeting TAK1 on collagenase-induced osteoarthritis in mice. Immunohistochemical staining confirmed significant elevation of TAK1 in osteoarthritic synovium, and immunofluorescence staining suggested macrophages as predominant residence of TAK1. In HMGB1-stimulated RAW264.7 macrophages, TAK1 expression was up-regulated both in mRNA and protein level. Besides, TAK1 inhibitor significantly impairs the production of TNF-α by macrophages upon HMGB1 stimulation. Moreover, intra-articular injection of lentivirus loaded with shRNA targeting TAK1 (sh-TAK1) reduced peri-articular osteophyte formation in collagenase-induced osteoarthritis in mice. TAK1 exerts a potent role in the pathogenesis of osteoarthritis by mediating the activation of macrophages

Intra-articular injection is a common way to deliver biologics to joints, but their effectiveness is limited by rapid clearance from the joint space. This barrier can be overcome by genetically modifying cells within the joint such that they produce anti-arthritic gene products endogenously, thereby achieving sustained, therapeutic, intra-articular concentrations of the transgene products without re-dosing. A variety of non-viral and viral vectors have been subjected to preclinical testing to evaluate their suitability for delivering genes to joints. The first transfer of a gene to a human joint used an ex vivo protocol involving retrovirally transduced, autologous, synovial fibroblasts. Recent advances in vector technology allow in vivo delivery using adeno-associated virus (AAV). We have developed an AAV vector encoding the interleukin-1 receptor antagonist (AAV.IL-1Ra) for injection into joints with osteoarthritis (OA). It showed efficacy and safety in equine and rat models of OA, leading to a recently-completed, investigator-initiated, Phase I, dose-escalation clinical trial in 9 subjects with mid-stage OA of the knee (. ClinicalTrials.gov. Identifier: NCT02790723). Three cohorts of three subjects with mild to moderate OA in the index knee were injected intra-articularly under ultrasound guidance with a low (10e11 viral genomes) medium (10e12 viral genomes) or high (10e13 viral genomes) dose of AAV.IL-1Ra and followed for one year. The data confirm safety, with evidence of sustained intra-articular expression of IL-1Ra and a clinical response in certain subjects. Funding for a subsequent Phase Ib trial involving 50 subjects (. ClinicalTrials.gov. Identifier: NCT05835895), expected to start later this year, has been acquired. Progress in this area has stimulated commercial activity and there are now at least seven different companies developing gene therapies for OA and a number of clinical trials are in progress. Acknowledgement: Clinical trial funded by US Department of Defense Clinical Trial Award W81XWH-16-1-0540

Despite osteoarthritis (OA) representing a large burden for healthcare systems, there remains no effective intervention capable of regenerating the damaged cartilage in OA. Mesenchymal stromal cells (MSCs) are adult-derived, multipotent cells which are a candidate for musculoskeletal cell therapy. However, their precise mechanism of action remains poorly understood. The effects of an intra-articular injection of human bone-marrow derived MSCs into a knee osteochondral injury model were investigated in C57Bl/6 mice. The cell therapy was retrieved at different time points and single cell RNA sequencing was performed to elucidate the transcriptomic changes relevant to driving tissue repair. Mass cytometry was also used to study changes in the mouse immune cell populations during repair. Histological assessment reveals that MSC treatment is associated with improved tissue repair in C57Bl/6 mice. Single cell analysis of retrieved human MSCs showed spatial and temporal transcriptional heterogeneity between the repair tissue (in the epiphysis) and synovial tissue. A transcriptomic map has emerged of some of the distinct genes and pathways enriched in human MSCs isolated from different tissues following osteochondral injury. Several MSC subpopulations have been identified, including proliferative and reparative subpopulations at both 7 days and 28 days after injury. Supported by the mass cytometry results, the immunomodulatory role of MSCs was further emphasised, as MSC therapy was associated with the induction of increased numbers of regulatory T cells correlating with enhanced repair in the mouse knee. The transcriptomes of a retrieved MSC therapy were studied for the first time. An important barrier to the translation of MSC therapies is a lack of understanding of their heterogeneity, and the consequent lack of precision in its use. MSC subpopulations with different functional roles may be implicated in the different phases of tissue repair and this work offers further insights into repair process

Introduction. Polyacrylamide hydrogel (iPAAG. 1. ), is CE marked for treating symptomatic knee osteoarthritis (OA), meeting the need for an effective, long-lasting, and safe non-surgical option. This study evaluates the efficacy and safety of a single 6 ml intra-articular injection of iPAAG in participants with moderate to severe knee OA over a 5-year post-treatment period, presenting data from the 4-year follow up. Method. This prospective multicentre study (3 sites in Denmark) involved 49 participants (31 females) with an average age of 70 (range 44 – 86 years). They received a single 6 mL iPAAG injection. All participants provided informed consent and re-consented to continue after 1 year. The study followed GCP principles and was approved by Danish health authorities and local Health Research Ethics committees. Twenty-seven participants completed the 4-year follow-up. The study evaluated WOMAC pain, stiffness, function, and Patient Global Assessment (PGA) of disease impact. Changes from baseline were analysed using a mixed model for repeated measurement (MMRM). Sensitivity analyses were applied on the extension data, where the MMRM analysis was repeated only including patients in the extension phase and an ANCOVA model was used, replacing missing values at 4-years with baseline values (BOCF). Results. The planned MMRM analysis (n=49) revealed a statistically significant decrease in WOMAC pain subscale scores (-22.0; 95%CI: -29.5; -14.4) from baseline to 4-years. Analysis of the extension phase (n=27) showed similar results (-21.8; 95%CI: -29.0; -14.6) compared to the initial analysis. Furthermore, BOCF analysis indicated a statistically significant reduction in WOMAC pain subscale scores from baseline (-13.0 units). Four new adverse events were reported between the 3-year and 4-year visits; none were related to treatment. Conclusions. This study shows that single injections of 6 ml intra-articular iPAAG were well tolerated and continued to provide clinically important effectiveness at 4-years after treatment. Acknowledgements. The study was sponsored by Contura International A/S

Bone marrow mesenchymal stromal cells were aspirated from immature male green fluorescent protein transgenic rats and cultured in a monolayer. Four weeks after the creation of the osteochondral defect, the rats were divided into three groups of 18: the control group, treated with an intra-articular injection of phosphate-buffered saline only; the drilling group, treated with an intra-articular injection of phosphate-buffered saline with a bone marrow-stimulating procedure; and the bone marrow mesenchymal stromal cells group, treated with an intra-articular injection of bone marrow mesenchymal stromal cells plus a bone marrow-stimulating procedure. The rats were then killed at 4, 8 and 12 weeks after treatment and examined. The histological scores were significantly better in the bone marrow mesenchymal stromal cells group than in the control and drilling groups at all time points (p < 0.05). The fluorescence of the green fluorescent protein-positive cells could be observed in specimens four weeks after treatment

Summary Statement. Intra-articular injection of humanised monoclonal anti-VEGF antibody (Bevacizumab, Avastin®) in a osteoarthritis rabbit model is related to positive restorative effects in terms of histopathologic evaluation. Introduction. Vascular endothelial growth factor (VEGF) is generally undetectable in adult human articular cartilage under physiological conditions. Upon exposure to pathological stimulation such as inflammation, hypoxia or accumulating mechanical stress, VEGF would be up regulated in hypertrophic chondrocytes of arthritic cartilage leading to osteophyte formation, disregulation of chondrocyte apoptosis and induction of catabolic factors, including matrix metalloproteinases (MMPs). This in vivo study aims to investigate the potential role of VEGF inhibition to treat Osteoarthritis (OA), through intra-articular injection of Bevacizumab, a humanised monoclonal anti-VEGF antibody, in a OA rabbit model. Methods. OA was induced in twelve adult male New Zealand rabbits surgically by monolateral Anterior Cruciate Ligament Transection (ACLT). The rabbits were randomly divided into two equal groups (experimental and control). Intra-articular injections of Bevacizumab or saline (control) were given 4 weeks after ACLT and were administered once a week for 4 time. Animal were sacrificed at 2 and 3 month time point an knee analyzed histologically and grossly. Histopathological variables such as the number of fibroblasts and inflammatory cells, collagenous matrix deposition, synovial hyperplasia, granulation tissue formation, vascular proliferation were evaluated. Results:The macroscopic evaluation of the knee in the experimental group revealed smooth joint surfaces of articular cartilage and no osteophyte formation compared to the control group that showed marked arthritis including synovial hypertrophy and osteophyte formation. Histologic assessment demonstrated, in the experimental group, significantly higher scores concerning number of microvessels, synovial hyperplasia, macrophage infiltration, collagenous matrix deposition, chondrocytes proliferation and apoptosis compared to the control group. Conclusion. In conclusion, VEGF modulation via intra-articular injection of Bevacizumab in a rabbit model of knee OA, resulted in reduction of articular cartilage degeneration through setting up an appropriate environment that prevent chondrocyte hypertrophy, apoptosis and osteophytes formation by blocking the intrinsic VEGF catabolic pathway, endochondral ossification, and the extrinsic VEGF-induced vascular invasion. VEGF-signaling inhibtion through Bevacizumab represent a potential way to treat OA

Hyaluronic acid (HA) is responsible for the viscoelastic properties of synovial fluid and cartilage. Compared to healthy joints, synovial fluid in osteoarthritic joints contains HA of lower concentration and molecular weight. Hyaluronic acid hybrid complexes are composed by long and short HA chains linked by H bonds. These rheological characteristics and viscoelastic properties were produced by thermal patented process without chemical modification. Chondroitin sulfate (CS) is one of the essential components of the articular cartilage matrix and plays a key role in cartilage's mechanical and elastic properties. Biotechnological chondroitin (CB) is produced through fermentative/biotechnological processes and, unlike CS, is not sulfated. It has been shown that CB to play a more significant role in the phenotypic maintenance of chondrocytes than chondroitin sulfate and increases their viability and proliferation. A recent A Single-Arm, Open-Label, Pilot Study was conducted to evaluate the safety and efficacy of a single-dose intra-articular injection of Hybrid Hyaluronic acid and Sodium Chondroitin in the Treatment of Symptomatic Hip Osteoarthritis. A single injection of HS-SC was well tolerated and safe in the treatment of symptomatic hip OA. The treatment demonstrated a rapid significant improvement in pain (VAS) and function (Lequesne's Index) up to 6 months of follow-up