Cartilage lacks the ability to self-repair when damaged, which can lead to the development of degenerative joint disease. Despite intensive research in the field of cartilage tissue engineering, there is still no regenerative treatment that consistently promotes the development of hyaline cartilage. Extracellular matrix (ECM) derived hydrogels have shown to support cell adhesion, growth and differentiation [1,2]. In this study, porcine articular cartilage was decellularized, solubilised and subsequently modified into a photo-crosslinkable methacrylated cartilage ECM hydrogel. Bone marrow derived mesenchymal stem/stromal cells (MSCs) were encapsulated into both methacrylated ECM hydrogels (ECM-MA) and gelatin methacryloyl (GelMA) as control hydrogel, and their chondrogenic potential was assessed using biochemical assays and histological analysis. We found that successful decellularization of the cartilage tissue could be achieved while preserving key ECM components, including collagen and glycosaminoglycans. A live-dead assay demonstrated good viability of MSCs withing both GelMA and ECM-MA hydrogels on day 7. Large increases in sGAG accumulation was observed after 21 days of culture in chondrogenic media in both groups. Histological analysis revealed the presence of a more fibrocartilage tissue in the GelMA group, while cells embedded within the ECM-MA showed a round and chondrocytic-like morphology. Both groups stained positively for proteoglycans and collagen, with limited evidence of calcium deposition following Alizarin Red staining. These results show that ECM-MA hydrogels support a hyaline cartilage phenotype and robust cartilaginous matrix production. Future studies will focus on the printability of ECM-MA hydrogels to enable their use as bioinks for the biofabrication of functional tissues

Introduction. Hip prosthetic joint infection (PJI) is a debilitating complication following joint replacement surgery, with significant impact on patients and healthcare systems. The INFection ORthopaedic Management: Evidence into Practice (INFORM: EP) study, builds upon the 6-year INFORM programme by developing evidence-based guidelines for the identification and management of hip PJI. Methods. A panel of 21 expert stakeholders collaborated to develop best practice guidelines based on evidence from the previous INFORM research programme. An expert consensus process was used to refine guidelines using RAND/UCLA criteria. The guidelines were then implemented over a 12-month period through a Learning Collaborative of 24 healthcare professionals from 12 orthopaedic centres in England. Qualitative interviews were conducted with 17 members of the collaborative and findings used to inform the development of an implementation support toolkit. Patient and public involvement contextualised the implementation of the guidelines. The study is registered with the ISCRTN (34710385). Result. The INFORM guidelines, structured around the stages of PJI management, were largely supported by surgeons, although barriers included limited awareness among non-surgical team members, lack of job planning for multidisciplinary teams, and challenges in ensuring timely referrals from primary care. Psychological support for patients was identified as a critical gap. Advanced Nurse Practitioners and multidisciplinary team (MDT) coordinators were seen as potential bridges to address these knowledge gaps. The guidelines were also viewed as a useful tool for service development. Conclusions. This study presents the first evidence-based guidelines for hip PJI management, offering a comprehensive approach to prevention, treatment, and postoperative care. Effective implementation is crucial, involving wider dissemination amongst primary and community care, as well as non-specialist treatment centres. Further resources are needed to ensure job planning for MDTs and psychological support for patients. Overall, this study lays the foundation for improved PJI management, benefiting patients and healthcare systems

Skeletal muscle tissue engineering has made progress towards production of functional tissues in line with the development in materials science and fabrication techniques. In particular, combining the specificity of 3D printing with smart materials has introduced a new concept called the 4D printing. Inspired by the unique properties of smart/responsive materials, we designed a bioink made of gelatin, a polymer with well-known cell compatibility, to be 3D printed on a magnetically responsive substrate. Gelatin was made photocrosslinkable by the methacrylate reaction (GELMA), and its viscosity was finetuned by blending with alginate which was later removed by alginate lyase treatment, so that the printability of the bioink as well as the cell viability can be finetuned. C2C12 mouse myoblasts-laden bioink was then 3D printed on a magnetic substrate for 4D shape-shifting. The magnetic substrate was produced using silicon rubber (EcoFlex) and carbonyl iron powders. After 3D printing, the bioink was crosslinked on the substrate, and the substrate was rolled with the help of a permanent magnet. Unrolled (Open) samples were used as the control group. The stiffness of the bioink matrix was found to be in the range of 13–45 kPa, which is the appropriate value for the adhesion of C2C12 cells. In the cell viability analysis, it was observed that the cells survived and could proliferate within the 7-day duration of the experiment. As a result of the immunofluorescence test, compared to the Open Group, more cell nuclei were observed overlapping MyoD1 expression in the Rolled Group; this indicated that the cells in these samples had more cell-cell interactions and therefore tended to form more myotubes. Acknowledgements: This research was supported by the TÜBİTAK 2211-A and YÖK 100/2000 scholarship programs

There is a lack of carriers for the local delivery of rifampicin (RIF), one of the cornerstone second defence antibiotic for Staphylococcus aureus deep bone infections (DBIs). RIF is also associated with systemic side effects, and known for causing rapid development of antibiotic resistance when given as monotherapy. We evaluated a clinically usedbi-phasic calcium sulphate/hydroxyapatite (CaS/HA) biomaterial as a carrier for dual delivery of RIF with vancomycin (VAN) or gentamicin (GEN). It was hypothesized that this combined approach could provide improved biofilm eradication and prevent the development of RIF resistance. Methods: 1) Biofilm eradication: Using a modified crystal violet staining biofilm quantification method, the antibiotics released at different time points (Day 1, 3, 7, 14, 21, 28 and 35) from the hemispherical pellets of CaS/HA(500 mg)-VAN (24.57 mg) / GEN (10.35 mg) composites with or without RIF (8.11 mg) were tested for their ability to disrupt the preformed 48-h old biofilms of S. aureus ATCC 25923, and S. aureus clinical strain P-3 in 96-well microtitre plate. For each tested group of antibiotic fractions, five separate wells were used (n=5). 2) Testing for resistance development: Similar to the method mentioned above the 48-h biofilm embeded bacteria exposed to antibiotic fractions from different time points continuously for 7 days. The biofilms remained were then tested for RIF resistant strains of bacteria. Overall, there was clear antibiofilm biofilm activity observed with CaS/HA-VAN/GEN+RIF combinations compared with CaS/HA-VAN/GEN alone. The S. aureus strains developed resistance to RIF when biofilms were subjected to CaS/HA-RIF alone but not with combinations of CaS/HA-VAN/GEN+RIF. Enhanced antibiofilm effects without development of RIF resistance indicates that biphasic CaS/HA loaded with VAN or GEN could be used as a carrier for RIF for additional local delivery in clinically demanding DBIs. Acknowledgement: We deeply acknowledge the Royal Fysiographic Society of Lund, Landshövding Per Westlings Minnesfond and the Stina and Gunnar Wiberg fond for financial support

Acetabular morphology and orientation differs from ethnic group to another. Thus, investigating the natural history of the parameters that are used to assess both was a matter of essence. Nevertheless, clarification the picture of normal value in our society was the main aim of this study. However, Acetabular head index (AHI) and center edge angle (CEA) were the most sensitive indicative parameters for acetabular dysplasia. Hence, they were the main variables used in evaluation of acetabular development. A cross-sectional retrospective study that had been done in a tertiary center. Computed tomography abdomen scouts’ radiographs of non-orthopedics patients were included. They had no history of pelvic or hips’ related symptoms or fractures in femur or pelvis. Images’ reports were reviewed to exclude those with tumors in the femur or pelvic bones. A total of 81 patients was included with 51% of them were males. The mean of age was 10.38± 3.96. CEA was measured using Wiberg technique, means of CEA were 33.71±6.53 and 36.50±7.39 for males and females, respectively. Nonetheless, AHI means were 83.81±6.10 and 84.66±4.17 for males and females, respectively. On the other hand, CEA was increasing by a factor 0.26 for each year (3-18, range). In addition, positive significant correlation was detected between CEA and age as found by linear regression r 2 0.460 (f(df1,79) =21.232, P ≤0.0001). Also, Body mass index (BMI) was positively correlated with CEA r 0.410, P 0.004). This study shows that obesity and aging are linked to increased CEA. Each ethnic group has its own normal values that must be studied to avoid premature diagnosis

Partial meniscectomy patients have a greater likelihood for the development of early osteoarthritis (OA). To prevent the onset of early OA, patient-specific treatment algorithms need to be created that predict patient risk to early OA after meniscectomy. The aim of this work was to identify patient-specific risk factors in partial meniscectomy patients that could potentially lead to early OA. Partial meniscectomy patients operated between 01/2017 and 12/2019 were evaluated in the study (n=317). Exclusion criteria were other pathologies or surgeries for the evaluated knee and meniscus (n = 114). Following informed consent, an online questionnaire containing demographics and the “Knee Injury and Osteoarthritis Outcome Score” (KOOS) questionnaire was sent to the patient. Based on the KOOS pain score, patients were classified into “low” (> 75) and “high” (< 75) risk patients, indicating risk to symptomatic OA. The “high risk” patients also underwent a follow-up including an MRI scan to understand whether they have developed early OA. From 203 participants, 96 patients responded to the questionnaire (116 did not respond) with 61 patients considered “low-risk” and 35 “high-risk” patients. Groups that showed a significant increased risk for OA were patients aged > 40 years, females, overweight (BMI >25 kg/m2 ≤ 30 kg/m2), and smokers (*p < 0.05). The “high-risk”-follow-up revealed a progression of early osteoarthritic cartilage changes in seven patients, with the remaining nineteen patients showing no changes in cartilage status or pain since time of operation. Additionally, eighteen patients in the high-risk group showed a varus or valgus axis deviation. Patient-specific factors for worse postoperative outcomes after partial meniscectomy and indicators for an “early OA” development were identified, providing the basis for a patient-specific treatment approach. Further analysis in a multicentre study and computational analysis of MRI scans is ongoing to develop a patient-specific treatment algorithm for meniscectomy patients

Introduction. Osteoarthritis (OA) causes pain, stiffness, and loss of function due to degenerative changes in joint cartilage and bone. In some forms of OA, exercise can alleviate symptoms by improving joint mobility and stability. However, excessive training after joint injury may have negative consequences for OA development. Sensory nerve fibers in joints release neuropeptides like alpha-calcitonin gene-related peptide (alpha-CGRP), potentially affecting OA progression. This study investigates the role of alpha-CGRP in OA pathogenesis under different exercise regimen in mice. Method. OA was induced in C57Bl/6J WT mice and alpha-CGRP KO mice via surgical destabilization of the medial meniscus (DMM) at 12 weeks of age (N=6). Treadmill exercise began 2 weeks post-surgery and was performed for 30 minutes, 5 days a week, for 2 or 6 weeks at intense (16 m/min, 15° incline) or moderate (10 m/min, 5° incline) levels. Histomorphometric assessment of cartilage degradation (OARSI scoring), serum cytokine analysis, immunohistochemistry, and nanoCT analysis were conducted. Result. OARSI scoring confirmed OA induction 4 weeks post-DMM surgery, with forced exercise exacerbating cartilage degradation regardless of intensity. No significant genotype-dependent differences were observed. Serum analysis revealed elevated cytokine levels associated with OA and inflammation in KO mice compared to WT mice 4 and 8 weeks post-surgery (VEGF-A, MCP-1, CXCL10, RANTES, MIP1-alpha, MIP1-beta, and RANKL). The observed effects were often exacerbated by intense exercise but rarely by DMM surgery. NanoCT analysis demonstrated increased sclerotic bone changes after 6 weeks of forced exercise in KO mice compared to WT mice. Conclusion. Our results suggest an OA promoting effect of exercise in early disease stages of posttraumatic OA. Intense exercise induced inflammatory processes correlated to increased cytokine levels in the serum that might exacerbate OA pathogenesis in later stages. The neuropeptide alpha-CGRP might play a role in protecting against these adverse effects

Introduction. Osteoporosis accounts for a major risk factor of fracture-associated disability or premature death in the elderly. Enhancement of bone anabolism for slowing osteoporosis is highly demanding. Exerkine fibronectin type III domain containing 5 (FNDC5) regulates energy metabolism, inflammation, and aging. This study was aimed to investigate whether Fndc5 signaling in osteoblasts changed estrogen deficiency-mediated bone loss or microarchitecture deterioration. Method. Female osteoblast-specific Fndc5 transgenic mice (Fndc5Tg), which overexpressed Fndc5 under the control of key osteoblast marker osteocalcin promoter, were given bilateral ovariectomy to induce estrogen deficiency-mediated osteoporosis. Bone mass, microstructures, and biomechanical properties were quantified using μCT imaging and material testing. Dynamic bone formation was traced using fluorescence calcein. Osteogenic differentiation and adipocyte formation of bone-marrow mesenchymal cells were investigated using von Kossa staining and Nile red staining, respectively. Serum osteocalcin, CTX-1 and TRAP5b levels were quantified using designated ELISA kits. Mitochondrial respiration was investigated using Seahorse Extracellular Flux Analyzer. Result. Fndc5Tg mice developed relatively higher bone mass and microarchitecture than wild-type mice. Fndc5 overexpression attenuated the losses of bone mineral density and trabecular network, including trabecular volume, thickness, and trabecular number, and improved cortical thickness and porosity in ovariectomized mice. Gain of Fndc5 function preserved biomechanical characteristics (maximum load, breaking force, and energy), serum bone formation marker osteocalcin levels, and bone formation rate, whereas it reduced serum bone resorption makers CTX-1 and TRAP5b levels, osteoclast overburden, and marrow adiposis. In vitro, Fndc5 reversed the estrogen deficiency-mediated mineralized matrix underproduction and adipocyte formation of bone-marrow mesenchymal cells, and inhibited osteoclast formation in osteoporotic bone. Mechanistically, Fndc5 activated AMPK signaling, promoting mitochondrial respiration and ATP production to enhance osteoblastic activity. Conclusion. Fndc5 signaling exerted bone-protective actions delaying estrogen deficiency-mediated osteoporosis. This study highlighted a new molecular remedial option for osteoporosis development by manipulating Fndc5 functions

Introduction. Promoting bone mass homeostasis keeps skeleton away from osteoporosis. a-Ketoglutarate (a-KG) is an indispensable intermediate of tricarboxylic acid cycle (TCA) process for cellular energy production. a-KG mitigates cellular senescence, tissue degeneration, and oxidative stress. We investigated whether a-KG affected osteoblast activity or osteoporosis development. Method. Serum and bone specimens were biopsied from 26 patients with osteoporosis or 24 patients without osteoporosis who required spinal surgery. Ovariectomized or aged mice were fed 0.25% or 0.75% a-KG in drinking water for 8 – 12 weeks ad libitum. Bone mineral density, trabecular/cortical bone microarchitecture, mechanical strength, bone formation, and osteoclastic erosion were investigated using mCT, material testing device, in vivo calcein labelling, and TRAP histochemical staining. Serum a-KG, osteocalcin, and TRAP5b levels were quantified using ELISA kits. Bone-marrow mesenchymal cells and macrophages were incubated osteogenic and osteoclastogenic media. Histone H3K27me3 levels and enrichment were investigated using immunoblotting and chromatin precipitation-PCR. Result. Serum a-KG levels in patients with osteoporosis were less than controls; and were correlated with T-scores of hips (R2 = 0.6471, P < 0.0001) and lumbar spine (R2 = 0.7235, P < 0.001) in osteoporosis (AUC = 0.9941, P < 0.001). a-KG supplement compromised a plethora of osteoporosis signs in ovariectomized or aged mice, including bone mass loss, trabecular bone microarchitecture deterioration, and mechanical strength loss. It elevated serum osteocalcin levels and decreased serum TRAP5b. a-KG preserved caclein-labelling bone formation and repressed osteoclast resorption. It reversed osteogenic differentiation of bone-marrow stromal cells and reduced osteoclast formation in ovariectomized mice. Mechanically, a-KG attenuated H3K27 hypermethylation and Runx2 transcription repression, improving mineralized matrix production in osteogenic cells. Conclusion. Decreased serum a-KG is correlated with human and murine osteoporosis. a-KG reverses bone loss by repressing histone methylation in osteoblasts. This study highlighted a-KG supplement as a new biochemical option for protecting osteoporosis

This study aimed to characterise the microarchitecture of bone in different species of animal leading to the development of a physiologically relevant 3D printed cellular model of trabecular (Tb) and cortical bone (CB). Using high resolution micro-computed tomography (μ-CT) bone samples from multiple species were scanned and analysed before creating in silico models for 3D printing. Biologically relevant printing materials with physical characteristics similar to that of in vivo bone will be selected and tested for printability. Porcine and murine bone samples were scanned using μ-CT, with a resolution of 4.60 μM for murine and 11 μM for porcine and reconstructed to determine the architectural properties of both Tb and CB independently. A region of interest, 1 mm in height, will be used to generate an in-silico 3D model with dimensions (10 mm. 3. ) and suitable resolution before being translated into printable G code using CAD assisted software. A 1 mm section of each bone was analysed, to determine the differences in the microarchitecture with the intent of setting a benchmark for the developmental 3D in vitro model to be comparable against. In contrast, porcine caudal vertebrae (PCV) have an increased volume due to the size of the bone sample. Interestingly, BV/TR for Tb is similar between species in all samples except murine femur. Murine tibia and PCV have a similar Tb. number and thickness, however different SMI shape and separation. μ-CT scanning and analysis permits tessellation of the 3D output which will lead to the generation of an in silico printable model. Biomaterials are currently under optimisation to allow printability and shape integrity to reflect the morphological and physiological properties of bone

Senescent chondrocyte and subchondral osteoclast overburden aggravate inflammatory cytokine and pro-catabolic proteinase overproduction, accelerating extracellular matrix degradation and pain during osteoarthritis (OA). Fibronectin type III domain containing 5 (FNDC5) is found to promote tissue homeostasis and alleviate inflammation. This study aimed to characterize what role Fndc5 may play in chondrocyte aging and OA development. Serum and macroscopically healthy and osteoarthritic cartilage were biopsied from patients with knee OA who received total knee replacement. Murine chondrocytes were transfected with Fndc5 RNAi or cDNA. Mice overexpressing Fndc5 (Fndc5Tg) were operated to have destabilized medial meniscus mediated (DMM) joint injury as an experimental OA model. Cellular senescence was characterized using RT-PCR analysis of p16INK4A, p21CIP1, and p53 expression together with ß-galactosidase activity staining. Articular cartilage damage and synovitis were graded using OARSI scores. Osteophyte formation and mechanical allodynia were quantified using microCT imaging and von Frey filament, respectively. Osteoclast formation was examined using tartrate-resistant acid phosphatase staining. Senescent chondrocyte and subchondral osteoclast overburden together with decreased serum FNDC5 levels were present in human osteoarthritic cartilage. Fndc5 knockdown upregulated senescence program together with increased IL-6, MMP9 and Adamts5 expression, whereas Alcian blue-stained glycosaminoglycan production were inhibited. Forced Fndc5 expression repressed senescence, apoptosis and IL-6 expression, reversing proliferation and extracellular matrix production in inflamed chondrocytes. Fndc5Tg mice showed few OA signs, including articular cartilage erosion, synovitis, osteophyte formation, subchondral plate sclerosis and mechanical allodynia together with decreased IL-6 production and few senescent chondrocytes and subchondral osteoclast formation during DMM-induced joint injury. Mechanistically, Fndc5 reversed histone H3K27me3-mediated IL-6 transcription repression to reduce reactive oxygen species production. Fndc5 loss correlated with OA development. It was indispensable in chondrocyte growth and anabolism. This study sheds light onto the anti-ageing and anti-inflammatory actions of Fndc5 to chondrocytes; and highlights the chondroprotective function of Fndc5 to compromise OA

The development of cytoplasmic processes from in situ chondrocytes is a characteristic feature of early osteoarthritis in human cartilage. The processes involve cytoskeletal elements and are distinct from the short primary cilia described in human chondrocytes. Vimentin is an intermediate filament playing an essential structural and signal-transduction role. We determined cellular levels and distribution of vimentin in chondrocytes of different morphologies in non-degenerate and mildly osteoarthritic cartilage. Femoral heads were obtained after consent from patients undergoing hip arthroplasty following femoral neck fracture. Cartilage explants were graded as non-degenerate (grade 0;G0) or mildly osteoarthritic (grade 1;G1) and labelled with the cytoplasmic dye CMFDA (5-chloromethylfluorescein-diacetate) for cell shape. Explants were cryosectioned and labelled for vimentin by fluorescence immunohistochemistry. In situ chondrocyte morphology was identified by confocal microscopy as either normal (rounded/elliptical) or abnormal (with one or more cytoplasmic process of ≥2µm) and vimentin levels and distribution determined semi-quantitatively and related to chondrocyte morphology. When all cells in G0 and G1 cartilage were compared, there was no difference between average levels of vimentin per cell (P=0.144)[6(261)];femoral heads:cells). When cells were separated on the basis of morphology, there was no difference between vimentin levels in cells with one or more cytoplasmic process compared to those of normal morphology (P>0.05;[6(261)]). However vimentin levels were much greater at the base of cytoplasmic processes compared to distant areas of the same cells (P=0.021)[5(29)]). Although overall levels of chondrocyte vimentin do not change in these early stages of osteoarthritis, the formation and structure of these substantial chondrocyte cytoplasmic processes involves changes to its distribution. These morphological changes are similar to those occurring during chondrocyte de-differentiation to fibroblasts reported in osteoarthritis which results in the formation of mechanically-inferior fibro-cartilage. Alterations to chondrocyte vimentin distribution either directly or indirectly may play a role in cartilage degeneration

Osteoporosis is a systemic skeletal disorder characterized by reduced bone mass and deterioration of bone microarchitecture, which results in increased bone fragility and fracture risk. Casein kinase 2-interacting protein-1 (CKIP-1) is a protein that plays an important role in regulation of bone formation. The effect of CKIP-1 on bone formation is mainly mediated through negative regulation of the bone morphogenetic protein pathway. In addition, CKIP-1 has an important role in the progression of osteoporosis. This review provides a summary of the recent studies on the role of CKIP-1 in osteoporosis development and treatment. Cite this article: X. Peng, X. Wu, J. Zhang, G. Zhang, G. Li, X. Pan. The role of CKIP-1 in osteoporosis development and treatment. Bone Joint Res 2018;7:173–178. DOI: 10.1302/2046-3758.72.BJR-2017-0172.R1

Mechanical loading plays an essential role in both tendon development and degradation. However, the underlying mechanism of how tendons sense and response to mechanical loading remains largely unknown. SPARC, a multifunctional extracellular matrix glycoprotein, modulates cell extracellular matrix contact, cell-cell interaction, ECM deposition and cell migration. Adult mice with SPARC deficiency exhibited hypoplastic tendons in load-bearing zone. By investigating tendon maturation in different stages, we found that hypoplastic tendons developed at around postnatal 3 weeks when the mice became actively mobile. The in vitro experiments on primary tendon derived stem cells demonstrated that mechanical loading induced SPARC production and AKT/S6K signalling activation, which was disrupted by deleting SPARC causing reduced collagen type I production, suggesting that mechanical loading was harmful to tendon homeostasis without SPARC. In vivo treadmill training further confirmed that increased loading led to reduced Achilles tendon size and eventually caused tendon rupture in SPARC-/− mice, whereas no abnormality was seen in WT mice after training. We then investigate whether paralysing the hindlimb of SPARC-/− mice using BOTOX from postnatal 2 weeks to 5 weeks would delay the hypoplastic tendon development. Increased patellar tendon thickness was shown in SPARC-/− mice by reducing mechanical loading, whereas opposite effect was seen in WT mice. Finally, we identified a higher prevalence of a missense SNP in the SPARC gene in patients who suffered from a rotator cuff tear. In conclusion, SPARC is a mechano-sensor that regulates tendon development and homeostasis

Osteoporosis is a progressive, chronic disease of bone metabolism, characterized by decreased bone mass and mineral density, predisposing individuals to an increased risk of fractures. The use of animal models, which is the gold standard for the screening of anti-osteoporosis drugs, raises numerous ethical concerns and is highly debated because the composition and structure of animal bones is very different from human bones. In addition, there is currently a poor translation of pre-clinical efficacy in animal models to human trials, meaning that there is a need for an alternative method of screening and evaluating new therapeutics for metabolic bone disorders, in vitro.

The aim of this project is to develop a 3D Bone-On-A-Chip that summarizes the spatial orientation and mutual influences of the key cellular components of bone tissue, in a citrate and hydroxyapatite-enriched 3D matrix, acting as a 3D model of osteoporosis. To this purpose, a polydimethylsiloxane microfluidic device was developed by CAD modelling, stereolithography and replica molding. The device is composed by two layers: (i) a bottom layer for a 3D culture of osteocytes embedded in an osteomimetic collagen-enriched matrigel matrix with citrate-doped hydroxyapatite nanocrystals, and (ii) a upper layer for a 2D perfused co-culture of osteoblasts and osteoclasts seeded on a microporous PET membrane.

Cell vitality was evaluated via live/dead assay. Bone deposition and bone resorption was analysed respectively with ALP, Alizarin RED and TRACP staining. Osteocytes dendrite expression was evaluated via immunofluorescence. Subsequently, the model was validated as drug screening platform inducing osteocytes apoptosis and administrating standard anti-osteoporotic drugs.

This device has the potential to substitute or minimize animal models in pre-clinical studies of osteoporosis, contributing to pave the way for a more precise and punctual personalized treatment.

Even minor lesions in articular cartilage (AC) can cause underlying bone damage creating an osteochondral (OC) defect. OC defects can cause pain, impaired mobility and can develop to osteoarthritis (OA). OA is a disease that affects nearly 10% of the population worldwide^[1], and represents a significant economic burden to patients and society^[2]. While significant progress has been made in this field, realising an efficacious therapeutic option for unresolved OA remains elusive and is considered one of the greatest challenges in the field of orthopaedic regenerative medicine^[3]. Therefore, there is a societal need to develop new strategies for AC regeneration. In recent years there has been increased interest in the use of tissue-specific aligned porous freeze-dried extracellular matrix (ECM) scaffolds as an off-the-shelf approach for AC repair, as they allow for cell infiltration, provide biological cues to direct target-tissue repair and permit aligned tissue deposition, desired in AC repair^[4]. However, most ECM-scaffolds lack the appropriate mechanical properties to withstand the loads passing through the joint^[5]. One solution to this problem is to reinforce the ECM with a stiffer framework made of synthetic materials, such as polylactic acid (PLA)^[6]. Such framework can be 3D printed to produce anatomically accurate implants^[7], attractive in personalized medicine. However, typical 3D prints are static, their design is not optimized for soft-hard interfaces (OC interface), and they may not adapt to the cyclic loading passing through our joints, thus risking implant failure. To tackle this limitation, more compliant or dynamic designs can be printed, such as coil-shaped structures^[8]. Thus, in this study we use finite element modelling to create different designs that mimic the mechanical properties of AC and prototype them in PLA, using polyvinyl alcohol as support. The optimal design will be combined with an ECM scaffold containing a tailored microarchitecture mimicking aspects of native AC.

Acknowledgments: This project has received funding from the European Union's Horizon Europe research and innovation MSCA PF programme under grant agreement No. 101110000.

For decades, universities and research centers have been applying modeling and simulation (M&S) to problems involving health and medicine, coining the expression in silico clinical trials. However, its use is still limited to a restricted pool of specialists. It is here proposed an easy-to-use cloud-based platform that aims to create a collaborative marketplace for M&S in orthopedics, where developers and model creators are able to capitalize on their work while protecting their intellectual property (IP), and researcher, surgeons and medical device companies can use M&S to accelerate time and to reduce costs of their research and development (R&D) processes. Digital libraries on . InSilicoTrials.com. are built on collaborations among first-rate research center, model developers, software, and cloud providers (partners). Their access is provided to life science and healthcare companies, clinical centers, and research institutes (users), offering them with several solutions for the different steps of the orthopedics and medical devices R&D process. The platform is built using the Microsoft Azure cloud services, conforming to global standards of security and privacy for healthcare, ensuring that clinical data is properly managed, protected, and kept private. The environment protects the IP of partners against the downloading, copying, and changing of their M&S solutions; while providing a safe environment for users to seamlessly upload their own data, set up and run simulations, analyze results, and produce reports in conformity with regulatory requirements. The proposed platform allows exploitation of M&S through a Software-as-a-Service delivery model. The pay-per-use pricing: 1. provide partners with a strong incentive to commercialize their high-quality M&S solutions; 2. enable users with limited budget, such as small companies, research centers and hospitals, to use advanced M&S solutions. Pricing of the M&S tools is based on specific aspects, such as particular features and computational power required, in agreement with the developing partner, and is distinct for different types of customers (i.e., academia or industry). The first medical devices application hosted on . InSilicoTrials.com. is NuMRis (Numerical Magnetic Resonance Implant Safety), implemented in collaboration with the U.S. F.D.A. Center for Devices and Radiological Health, and ANSYS, Inc. The automatic tool allows the investigation of radiofrequency (RF)-induced heating of passive medical implants, such as orthopedic devices (e.g., rods and screws), pain management devices (e.g., leads), and cardiovascular devices (e.g., stents), following the ASTM F2182-19e2 Standard Test Method. NuMRis promotes the broader adoption of digital evidence in preclinical trials for RF safety analysis, supporting the device submission process and pre-market regulatory evaluation. InSilicoTrials.com. aims at defining a new collaborative framework in healthcare, engaging research centers to safely commercialize their IP, i.e., model templates, simulation tools and virtual patients, by helping clinicians and healthcare companies to significantly expedite the pre-clinical and clinical development phases, and to move across the regulatory approval and HTA processes

Tendinopathies represent the 45% of the musculoskeletal lesions and they are a big burden in clinics. Indeed, despite the relevant social impact, both the pathogenesis and the development of the tendinopathy are still under-investigated, thus limiting the therapeutic advancement in this field. Indeed, current treatment for tendinopathy are mainly symptomatic, and they present a high rate of pathology re-occurrence. In this contest, the development of an efficient in vivo model of acute tendinopathy, focused on the choice of the most appropriate species and strategy to induce the disease, would allow a better understanding of the pathology progression throughout its phases. Then, the purpose of this study was to evaluate the dose-dependent and time-related tissue-level changes occurring in a collagenase-induced tendinopathy in rat Achilles tendons, in order to establish a standardized model for future pre-clinical studies. 40 Sprague Dawley rats were randomly divided into two groups, treated by injection of collagenase type I within the Achilles tendon at 1 mg/mL (low dose, LD) or 3 mg/mL (high dose, HD). Tendon explants were histologically evaluated at 3, 7, 15, 30 and 45 days by H&E staining. Our results showed that both the collagenase doses induced a disorganization of collagen fibers and increased the number of rounded resident cells. In particular, the high dose treatment determined a greater fatty degeneration and neovascularization with respect to the lower dose. These changes are time-dependent, thus resembling the tendinopathy development in humans. Indeed, the acute phase occurred from day 3 to day 15, while from day 15 to 45 it progressed towards the proliferative phase, displaying a degenerative appearance associated with a precocious remodeling process. The model represents a good balance between feasibility, in terms of reproducibility and costs, and similarity with the human disease. Moreover, the present model contributes to improve the knowledge about tendinopathy development, and then it could be useful to design further pre-clinical studies, in particular in order to test innovative treatments for tendinopathy

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.

Hip joint biomechanics can be altered by abnormal morphology of the acetabulum and/or femur. This may affect load distribution and contact stresses on the articular surfaces, hence, leading to damage and degradation of the tissue. Experimental hip joint simulators have been used to assess tribology of total hip replacements and recently methods further developed to assess the natural hip joint mechanics. The aim of this study was to evaluate articular surfaces of human cadaveric joints following prolonged experimental simulation under a standard gait cycle.

Four cadaveric male right hips (mean age = 62 years) were dissected, the joint disarticulated and capsule removed. The acetabulum and femoral head were mounted in an anatomical hip simulator (Simulation Solutions, UK). A simplified twin peak gait cycle (peak load of 3kN) was applied. Hips were submerged in Ringers solution (0.04% sodium azide) and testing conducted at 1 Hertz for 32 hours (115,200 cycles). Soft tissue degradation was recorded using photogrammetry at intervals throughout testing.

All four hips were successfully tested. Prior to simulation, two samples exhibited articular surface degradation and one had a minor scalpel cut and a small area of cartilage delamination. The pre-simulation damage got slightly worse as the simulation continued but no new areas of damage were detected upon inspection. The samples without surface degradation, showed no damage during testing and the labral sealing effect was more obvious in these samples.

The fact that no new areas of damage were detected after long simulations, indicates that the loading conditions and positioning of the sample were appropriate, so the simulation can be used as a control to compare mechanical degradation of the natural hip when provoked abnormal conditions or labral tissue repairs are simulated.