Comparative effectiveness of two methods for inducing osteoarthritis in a novel animal model, the Diannan small-ear pig

Background Varieties of animals were used to study osteoarthritis pathogenesis. The Diannan small-ear pig, which is native to Yunnan, China, is thought to have an articular anatomy similar to that of humans and is more likely to be a source of pathological tissues than other animals. The aim of this study was to determine whether this animal can serve as a more effective osteoarthritis model and explore the role of SDF-1/CXCR4 signaling pathway in the development of Osteoarthritis in animals. Methods Twenty-seven adult pigs were randomly divided into three groups and underwent the Hulth procedure, papain articular injection, and conventional breeding. After 4, 8, and 12 weeks, cartilage tissues from knee joint were extracted for general and histological observation, immunofluorescence, and biochemical analysis. Synovium was taken out for stromal cell-derived factor-1 analysis. Results Histopathological observation showed obvious cartilage loss in two experimental groups, this cartilage loss was more severe in the chemical groups. Synovial stromal cell-derived factor1 levels increased over time in all groups. mRNA and protein levels of matrix metalloproteinase-3 were much higher in the chemical groups than in the other groups, whereas levels of collagen type II and aggrecan were significantly lower in the chemical groups than in the other groups. Immunofluorescence assays of collagen type II revealed an apparent reduction in this marker in the chemical groups compared with the other groups. Conclusions These results indicated that the Diannan small-ear pig can be used as an effective osteoarthritis model. In addition, it is much more convenient and much faster to induce osteoarthritis by intra-articular injection of papain, which is a method worthy of being promoted.

Early Knee Osteoarthritis Changes Pre- And Post-Anterior Cruciate Ligament Reconstruction Assessed By the Semi-Quantitative MRI Osteoarthritis Knee Score (MOAKS) Case Series and Case-Control Study

Background: Semi-quantitative scoring of knee abnormalities on magnetic resonance imaging (MRI) can aid in the diagnosis of early stage knee osteoarthritis (OA). Injuries to the anterior cruciate ligament (ACL) and medial meniscus (MM) can contribute to the development of knee OA, but their relationship to its time of onset is unknown.Purpose: To analyze the factors contributing to early knee OA changes in ACL injured knees using MRI Osteoarthritis Knee Score (MOAKS). Methods: Thirty-four cases status post unilateral ACL reconstruction (ACLR) were included. Knee OA abnormalities were evaluated using MOAKS scores of MRIs performed pre- and post-ACLR. Using multiple linear regression analysis, the MOAKS scores of medial osteophytes, medial cartilage alteration, and patellofemoral cartilage alteration were determined as dependent variables. Age, the presence of a meniscal abnormality, the time from injury to ACLR, and body mass index (BMI) were determined as explanatory variables. MOAKS differences between knees with and without medial meniscus (MM) abnormality were tested for each variable using a 2-way repeated-measures analysis of variance with the factors of preoperative vs. postoperative status and MM abnormality. Results: In the pre-ACLR multiple linear regression analysis, the waiting period was significantly and positively associated with medial cartilage loss, Lateral femorotibial osteophytes, lateral cartilage loss. and BMI were positively associated with MM abnormalities. BMI and lateral meniscus (LM) abnormality were significantly associated with lateral cartilage loss. Age was significantly associated with medial osteophytes. Age and LM abnormality were significantly associated with lateral osteophytes. Age, BMI, and LM abnormality were significantly associated with patellofemoral osteophytes. Conclusion: We found early knee OA changes in most knees a mean of 28.2 ± 52.0 months after ACL injury. The time from injury to ACLR, BMI, and the presence of MM or LM abnormality in the ACL injured knee were associated with early knee OA changes. In the ACL injured knee with MM involvement, prompt ACLR may forestall the development of OA.

The ability to kneel before and after total knee arthroplasty

Aims The aims of this study were to investigate the ability to kneel after total knee arthroplasty (TKA) without patellar resurfacing, and its effect on patient-reported outcome measures (PROMs). Secondary aims included identifying which kneeling positions were most important to patients, and the influence of radiological parameters on the ability to kneel before and after TKA. Methods This prospective longitudinal study involved 209 patients who underwent single radius cruciate-retaining TKA without patellar resurfacing. Preoperative EuroQol five-dimension questionnaire (EQ-5D), Oxford Knee Score (OKS), and the ability to achieve four kneeling positions were assessed including a single leg kneel, a double leg kneel, a high-flexion kneel, and a praying position. The severity of radiological osteoarthritis (OA) was graded and the pattern of OA was recorded intraoperatively. The flexion of the femoral component, posterior condylar offset, and anterior femoral offset were measured radiologically. At two to four years postoperatively, 151 patients with a mean age of 70.0 years (SD 9.44) were included. Their mean BMI was 30.4 kg/m2 (SD 5.36) and 60 were male (40%). They completed EQ-5D, OKS, and Kujala scores, assessments of the ability to kneel, and a visual analogue scale for anterior knee pain and satisfaction. Results The ability to kneel in the four positions improved in between 29 (19%) and 53 patients (35%) after TKA, but declined in between 35 (23%) and 46 patients (30%). Single-leg kneeling was most important to patients. After TKA, 62 patients (41%) were unable to achieve a single-leg kneel, 76 (50%) were unable to achieve a double-leg kneel, 102 (68%) were unable to achieve a high-flexion kneel and 61 (40%) were unable to achieve a praying position. Posterolateral cartilage loss significantly affected preoperative deep flexion kneeling (p = 0.019). A postoperative inability to kneel was significantly associated with worse OKS, Kujala scores, and satisfaction (p < 0.05). Multivariable regression analysis identified significant independent associations with the ability to kneel after TKA (p < 0.05): better preoperative EQ-5D and flexion of the femoral component for single-leg kneeling; the ability to achieve it preoperatively and flexion of the femoral component for double-leg kneeling; male sex for high-flexion kneeling; and the ability to achieve it preoperatively, anterior femoral offset, and patellar cartilage loss for the praying position. Conclusion The ability to kneel was important to patients and significantly influenced knee-specific PROMs, but was poorly restored by TKA with equal chances of improvement or decline. Cite this article: Bone Joint J 2021;103-B(9):1514–1525.

Alterations in cartilage quantification before and after injections of mesenchymal stem cells into osteoarthritic knees

Several studies have reported improvement in knee pain following mesenchymal stem cell (MSC) injections for knee osteoarthritis (OA). We developed a novel 3D magnetic resonance imaging (MRI) analysis software program that provides “projected cartilage area ratios” for automatic detection of changes in cartilage amounts. The primary objective of this prospective interventional study was to compare alterations in the projected cartilage area ratio (thickness ≥ 1.5 mm) at the femoral posteromedial region between 30 weeks before and 30 weeks after synovial MSC injections. Secondary objectives were to assess the clinical scores and safety of MSC injections. Patients with OA who complained of knee pain underwent autologous synovial MSC injections into the knee at time 0 and again 15 weeks later. MRI examinations were performed at − 30, − 15, − 1, and 30 weeks. Patients showing < 3% decreases in the projected cartilage area ratio (thickness ≥ 1.5 mm) at the femoral the posteromedial region from − 30 weeks to − 15 weeks were excluded from the study. The Lysholm Knee Score, Knee Injury and Osteoarthritis Outcome Scale (KOOS), and Numerical Rating Scale (NRS) scores were evaluated at − 30, − 15, − 5, − 2, 0, 5, 10, 15, 20, 25, and 30 weeks. Five patients were excluded because 3D MRI analysis showed no cartilage loss at − 15 weeks. Ultimately, eight OA patients underwent MSC injections. The projected cartilage area ratio significantly decreased by 0.07 in the 30 weeks before MSC injections (p = 0.01), but no further decreases occurred in the 30 weeks after MSC injections. The projected cartilage area ratio at the femoral posteromedial region showed a significant difference between 30 weeks before and 30 weeks after MSC injections. The Lysholm Knee Score, KOOS, and NRS values improved significantly after the injections. MSC injection could not be ruled out as the cause of two adverse events: transient knee pain and itching in both hands. Fully automatic 3D MRI analysis showed that synovial MSC injections suppressed cartilage loss in patients with progressive OA.Trial registration: Intraarticular injections of synovial stem cells for osteoarthritis of the knee (Number UMIN 000026732). Date of registration; June 1, 2017. https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000029967.

AB0030 BETA BOSWELLIC ACID BLOCKS INNATE IMMUNE RESPONSES IN MULTIPLE OA JOINT CELLS

Background:Osteoarthritis (OA) incidence has skyrocketed in the last decade and yet a definitive treatment has still to be found. This worldwide disease is depriving our society from their life quality and has become a grave economic burden. Research on anti-inflammatory tools has been done on traditional Asian medicine. Boswellic acid is a plant-derived molecule from the Boswellia species that has shown to prevent cartilage loss in an OA mouse model[1]. However, the specific mechanism of action is still unclear. The activation of innate immune receptors, such Toll-like receptor 4 (TLR4) has been involved in chondrocyte-mediated inflammatory responses and OA development. Although, boswellic acid has shown an inhibitory effect on TLR4-mediated inflammatory responses little is known about its role on TLR4-mediated chondrocyte inflammatory and catabolic responses.Objectives:Determine the ability of beta boswellic acid (BBA) to block TLR4-mediated innate immune responses in chondrocytes and synoviocytes.Methods:In silicoThe binding affinity of beta boswellic acid (BBA) to TLR4 complex signalling was determined by optimized docking algorithm in the BIO-HPC Research Group facilities.In vitroCellular proteome and secretome profiling (LC-MALDI/TOFF) was used to study inflammatory pathways induced by the agonist of TLR4 (LPS [100ng/ml]) and IL1R (IL1β [0.1ng/ml]). The effect of BBA on TLR4-mediated innate immune responses was determined by RT-PCR, Western Blot and ELISA in primary human OA chondrocytes (hOC), murine ATDC5 chondrocytes, human synoviocytes (SW982) and primary human osteoblasts (hOB). Cell viability was tested using the methyl-thiazolyl-tetrazolium (MTT) reagent. Nitric oxide production in cell culture media was assessed by Griess reaction. Green Malachite Assay was used to semi-quantify the whole phosphoproteome.EthicsThis study was approved by the CEIC (CAEIG 2014/310).Results:Cellular proteome and secretome profiling validated the activation of TLR4 and IL1R signalling by LPS and IL1β ligands and revealed an enrichment in innate immune responses (NF-Kβ, NLRP3, MMPs, Interleukins, etc).Non-toxic doses of BBA [0.5-1000nM] prevented the activation of TLR4 in multiple articular joint cells and inhibited TLR4 & IL1R-dependant innate immune responses at the mRNA and protein level such as inflammatory factors IL6, NOS2, COX2, LCN2, MMP1, -3, -9, -13 and ADAMTS4, among others. Furthermore, NF-Kβ/IKBα and NLRP3/PYCARD/IL1β axis were also severely inhibited after BBA treatment. Moreover, these results were validated by in silico docking analysis that showed BBA interacted with TLR4/NF-Kβ.Conclusion:We prove that BBA inhibit TLR4 & IL1R -dependent innate immune responses in multiple human joint cells (Figure 1). We show that NF-Kβ & NLRP3 signalling, both associated to OA, are blocked (mRNA and protein) after BBA treatment (Figure 1).Our data support previous studies showing the prevention of cartilage loss in an OA animal models by BBA might come from its ability to inhibit TLR4 signalling. In the clinical practice of rheumatologists, Boswellia Serrata could be a useful nutraceutical to manage OA inflammation due to its content in BBA.Figure 1.References:[1]Wang, Q.; Pan, X.; Wong, H.H.; Wagner, C.A.; Lahey, L.J.; Robinson, W.H.; Sokolove, J. Oral and topical boswellic acid attenuates mouse osteoarthritis. Osteoarthr. Cartil.2014, 22, 128–132, doi:10.1016/j.joca.2013.10.012.Acknowledgements:Eloi Franco-Trepat and Ana Lois-Iglesias contributed equally to this work.This research has been funded by the non-profit FER (Fundación Española de Reumatologia /Spanish Foundation of Rheumatology) through the project “Búsqueda de nuevos fármacos bloqueantes de la inflamación asociada a TLR4 en condrocitos humanos artrósicos”.Disclosure of Interests:None declared

POS0186 METABOLOMIC SIGNATURES FOR KNEE CARTILAGE VOLUME LOSS OVER 10 YEARS

Background:Osteoarthritis (OA) is the most common form of arthritis, and its impact is increasing year by year due to an aging population and lack of effective treatments. One of the main structural pathological changes of OA is the loss of articular cartilage. Tools that can predict cartilage loss would help identify people at high risk, thus preventing OA development.Objectives:Using a metabolomics approach, the current study aimed to identify serum metabolomic signatures for predicting the loss of knee cartilage volume over 10 years in a well-established community-based cohort - the Tasmania Older Adult Cohort (TASOAC).Methods:TASOAC is an on-going, prospective, population-based study of older adults who were randomly selected from the roll of electors in Southern Tasmania, Australia. Participants had a right knee magnetic resonance imaging (MRI) scan at baseline and a 10-year follow-up. Cartilage volume was measured in the medial, lateral, and patellar compartments and change in cartilage volume over 10 years was calculated as percentage change per year. Fasting serum samples collected at 2.6-year follow-up were metabolomically profiled using the TMIC Prime Metabolomics Profiling Assay which measures a total of 143 metabolites. 129 metabolite concentrations passed the quality control and the pairwise ratios of them as the proxies of enzymatic reaction were calculated. Linear regression models were used to test the association between each of the metabolite ratios and change in cartilage volume in each of the knee compartments with adjustment for age, sex, and body mass index (BMI). The significance was defined at a=3.0×10-6 to control multiple testing of 16,512 ratios with Bonferroni method.Results:A total of 344 participants (51% females) were included. The mean baseline age was 62.83±6.13 years and the mean BMI was 27.48±4.41 kg/m2. The average follow-up time was 10.84±0.66 years. Cartilage volume reduced by 1.34±0.72%, 1.06±0.58%, and 0.98±0.46% per year in the medial, lateral, and patellar compartments, respectively. Our data showed that an increased ratio of hexadecenoylcarnitine (C16:1) to tetradecanoylcarnitine (C14) was associated with a 0.12±0.02% per year reduction in patellar cartilage volume (p = 8.80×10-7). An increased ratio of hexadecenoylcarnitine (C16:1) to dodecanoylcarnitine (C12) was also associated with a 0.12±0.02% per year reduction in patellar cartilage volume (p = 2.66×10-6). While there were several metabolite ratios associated with cartilage volume loss in the medial and lateral compartments, none of them reached the predefined significance level.Conclusion:Our data suggested that alteration of fatty acid β-oxidation is involved in knee cartilage loss, especially in the patellar compartment, and the serum ratio of C16:1 to C14 and to C12 could be used to predict long-term patellar cartilage loss.Acknowledgements:We thank all the study participants who made the study possible. The original TASOAC study was supported by the National Health and Medical Research Council (NHMRC) and the current study was supported by the Canadian Institutes of Health Research (CIHR).Disclosure of Interests:None declared