Developing strategic priorities in osteoarthritis research: Proceedings and recommendations arising from the 2017 Australian Osteoarthritis Summit

Mechanistic Exploration of Smilax glabra Roxb. in Osteoarthritis: Insights from Network Pharmacology, Molecular Docking, and In Vitro Validation

Background: Arthritis, a debilitating joint disease, remains a significant global health burden. This study uncovers the therapeutic potential of the medicinal plant Smilax glabra Roxb. (SGR) in attenuating progression of disease by modulating immune responses. Methods: Through computational approaches, key bioactive compounds in SGR were identified by using freely available databases: TCMSP, TCMID, HIT2.0, HERB, and INPUT in order to elucidate their underlying mechanisms of action. Therapeutic targets for the disease have been retrieved by TTD, GeneCard, and OMIM databases. The STRING database was used to analyze the protein-protein interactions (PPI) of intersecting genes. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed to reveal the functional roles of genes. Mcule was used for molecular docking and binding affinity of compounds and targets were evaluated by DeepPurpose model. ALP activity, cell viability assay, TRAP staining were also performed. Results: A total of 14 active SGR compounds with 59 common targets for arthritis have been identified. These targets have a major role in controlling biological processes such as wound healing, oxygen responses, and chemical stimuli. Molecular docking by Mcule platform demonstrated that quercetin and β-sitosterol showed higher binding energy affinities with TNF, TP53, PTGS2, and JUN as compared to other targets. To explore the complex relationship between compounds and targets, pre-trained Davis and KIBA models were used to predict the affinity values of selected compounds. In MC3T3-E1 cells, ALP activity was significantly increased and bone marrow macrophages (BMM) showed a low number of TRAP-positive cells in SGR-treated cells. Conclusions: Our findings demonstrate that SGR effectively inhibits/regulates inflammatory responses, prevents cartilage degradation, promotes bone regeneration, and can be used as a promising candidate for the development of novel arthritis treatment.

Exploring different models of pain phenotypes and their association with pain worsening in people with early knee osteoarthritis: The MOST cohort study

OBJECTIVE

To determine i) pain phenotypes (PP) in people with early-stage knee osteoarthritis (EKOA); ii) the longitudinal association between the phenotypes and pain worsening at two years.

DESIGN

We studied participants with EKOA from the Multicenter Osteoarthritis Study defined as pain intensity ≤3/10, Kellgren and Lawrence grade ≤2, intermittent pain none to sometimes, and no constant pain. Two models of PP were explored. Model A included pressure pain thresholds, temporal summation, conditioned pain modulation, pain catastrophizing, sleep quality, depression, and widespread pain (WSP). In Model B, gait characteristics, quadriceps strength, comorbidities, and magnetic resonance imaging features were added to Model A. Latent Class Analysis was used to create phenotypes, and logistic regression was used to determine their association with pain worsening.

RESULTS

750 individuals (60% females), mean age [standard deviation (SD)]: 60.3 (9.4) were included in Model A and 333 individuals (60% females), mean age (SD): 59.4 (8.1) in Model B. 3-class and 4-class solutions were chosen for Model A and Model B. In Model A, the most "severe" phenotype was dominated by psychosocial factors, WSP, and measures of nervous system sensitization. Similarly in Model B, the Model A phenotype plus gait variables, quadriceps strength, and comorbidities were dominant. Surprisingly, none of the phenotypes in either model had a significant relationship with pain worsening.

CONCLUSION

Phenotypes based upon various factors thought to be important for the pain experience were identified in those with EKOA but were not significantly related to pain worsening. These phenotypes require validation with clinically relevant endpoints.

Trajectories of physical function and quality of life in people with osteoarthritis: results from a 10-year population-based cohort

OBJECTIVE

To identify long-term trajectories of physical function and health-related quality of life (HRQoL) among people with hip and/or knee osteoarthritis (HKOA) and the sociodemographic, lifestyle, and clinical factors associated with different trajectories.

METHODS

Participants with HKOA from the EpiDoC study, a 10-year follow-up (2011-2021) population-based cohort, were considered. Sociodemographic, lifestyle, and clinical variables were collected at baseline in a structured interview and clinical appointment. Physical function and HRQoL were evaluated with the Health Assessment Questionnaire (HAQ) and EuroQoL, respectively, at baseline and the three follow-ups. Group-based trajectory modeling identified physical function and HRQoL trajectories. Multinomial logistic regression analyzed the associations between the covariates of interest and trajectory assignment (p < 0.05).

RESULTS

We included 983 participants with HKOA. We identified three trajectories for each outcome: "consistently low disability" (32.0%), "slightly worsening moderate disability" (47.0%), and "consistently high disability" (21.0%) for physical function; "consistently high HRQoL" (18.3%), "consistently moderate HRQoL" (48.4%) and "consistently low HRQoL" (33.4%) for HRQoL. Age ≥ 75 years, female sex, multimorbidity, and high baseline clinical severity were associated with higher risk of assignment to poorer physical function and HRQoL trajectories. Participants with high education level and with regular physical activity had a lower risk of assignment to a poor trajectory. Unmanageable pain levels increased the risk of assignment to the "consistently moderate HRQoL" trajectory.

CONCLUSION

Although the trajectories of physical function and HRQoL remained stable over 10 years, approximately 70% of people with HKOA maintained moderate or low physical function and HRQoL over this period. Modifiable risk factors like physical activity, multimorbidity and clinical severity were associated with poorer physical function and HRQoL trajectories. These risk factors may be considered in tailored healthcare interventions.

3D profiling of mouse epiphyses across ages reveals new potential imaging biomarkers of early spontaneous osteoarthritis

Worldwide research groups and funding bodies have highlighted the need for imaging biomarkers to predict osteoarthritis (OA) progression and treatment effectiveness. Changes in trabecular architecture, which can be detected with non-destructive high-resolution CT imaging, may reveal OA progression before apparent articular surface damage. Here, we analysed the tibial epiphyses of STR/Ort (OA-prone) and CBA (healthy, parental control) mice at different ages to characterise the effects of mouse age and strain on multiple bony parameters. We isolated epiphyseal components using a semi-automated method, and measured the total epiphyseal volume; cortical bone, trabecular bone and marrow space volumes; mean trabecular and cortical bone thicknesses; trabecular volume relative to cortical volume; trabecular volume relative to epiphyseal interior (trabecular BV/TV); and the trabecular degree of anisotropy. Using two-way ANOVA (significance level ≤0.05), we confirmed that all of these parameters change significantly with age, and that the two strains were significantly different in cortical and trabecular bone volumes, and trabecular degree of anisotropy. STR/Ort mice had higher cortical and trabecular volumes and a lower degree of anisotropy. As the two mouse strains reflect markedly divergent OA predispositions, these parameters have potential as bioimaging markers to monitor OA susceptibility and progression. Additionally, significant age/strain interaction effects were identified for total epiphyseal volume, marrow space volume and trabecular BV/TV. These interactions confirm that the two mouse strains have different epiphyseal growth patterns throughout life, some of which emerge prior to OA onset. Our findings not only propose valuable imaging biomarkers of OA, but also provide insight into ageing 3D epiphyseal architecture bone profiles and skeletal biology underlying the onset and development of age-related OA in STR/Ort mice.

What are the research priorities for optimising the safe and effective use of opioids in Australian general practice?

INTRODUCTION

Persistent high rates of prescription opioid use and harms remain a concern in Australia, Europe and North America. Research priority setting can inform the research agenda, strategic responses and evidence-based interventions. The objective of this study was to establish research priorities related to the safe and effective use of prescription opioids in general practice.

METHODS

Consumers, clinicians and policy makers were invited to participate in a structured consensus workshop in May 2021. A modified nominal group technique was used to explore research priorities for the safe and effective use of opioids in Australian general practice. Research priorities were identified, consolidated and prioritised using a structured process.

RESULTS

Seventeen consumer, medical, pharmacy, nursing, allied health and policy participants generated 26 consolidated priorities across three domains: (i) consumer-focused priorities; (ii) clinician and practice-focused priorities; and (iii) system and policy-focused priorities. The highest ranked research priorities in each of the domains were consumer characteristics that influence opioid prescribing and outcomes, opioid deprescribing strategies, and system-level barriers to prescribing alternatives to opioids, in the consumer, clinician and practice, and system and policy domains, respectively.

DISCUSSION AND CONCLUSION

The priorities reflect opportunities for research priority setting within Australian general practice. The priorities provide a map for future qualitative and quantitative research that will inform safe and effective opioid prescribing.

Effects of neuromuscular gait modification strategies on indicators of knee joint load in people with medial knee osteoarthritis: A systematic review and meta-analysis

OBJECTIVES

This systematic review aimed to determine the effects of neuromuscular gait modification strategies on indicators of medial knee joint load in people with medial knee osteoarthritis.

METHODS

Databases (Embase, MEDLINE, Cochrane Central, CINAHL and PubMed) were searched for studies of gait interventions aimed at reducing medial knee joint load indicators for adults with medial knee osteoarthritis. Studies evaluating gait aids or orthoses were excluded. Hedges' g effect sizes (ES) before and after gait retraining were estimated for inclusion in quality-adjusted meta-analysis models. Certainty of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

RESULTS

Seventeen studies (k = 17; n = 362) included two randomised placebo-controlled trials (RCT), four randomised cross-over trials, two case studies and nine cohort studies. The studies consisted of gait strategies of ipsilateral trunk lean (k = 4, n = 73), toe-out (k = 6, n = 104), toe-in (k = 5, n = 89), medial knee thrust (k = 3, n = 61), medial weight transfer at the foot (k = 1, n = 10), wider steps (k = 1, n = 15) and external knee adduction moment (KAM) biofeedback (k = 3, n = 84). Meta-analyses found that ipsilateral trunk lean reduced early stance peak KAM (KAM1, ES and 95%CI: -0.67, -1.01 to -0.33) with a dose-response effect and reduced KAM impulse (-0.37, -0.70 to -0.04) immediately after single-session training. Toe-out had no effect on KAM1 but reduced late stance peak KAM (KAM2; -0.42, -0.73 to -0.11) immediately post-training for single-session, 10 or 16-week interventions. Toe-in reduced KAM1 (-0.51, -0.81 to -0.20) and increased KAM2 (0.44, 0.04 to 0.85) immediately post-training for single-session to 6-week interventions. Visual, verbal and haptic feedback was used to train gait strategies. Certainty of evidence was very-low to low according to the GRADE approach.

CONCLUSION

Very-low to low certainty of evidence suggests that there is a potential that ipsilateral trunk lean, toe-out, and toe-in to be clinically helpful to reduce indicators of medial knee joint load. There is yet little evidence for interventions over several weeks.

Clinical Safety and Effectiveness of Adipose-Derived Stromal Cell vs Stromal Vascular Fraction Injection for Treatment of Knee Osteoarthritis: 2-Year Results of Parallel Single-Arm Trials

BACKGROUND

There are currently no disease-modifying treatments available for knee osteoarthritis (OA), although cultured adipose-derived stromal cells (ASCs) have shown promise in experimental models. However, given the regulatory limits on the use of cultured cells in humans, previous trials have focused primarily on the stromal vascular fraction (SVF) intra-articular injection. Therefore, the therapeutic value of ASCs for knee OA remains unknown.

PURPOSE

To study ASC versus SVF intra-articular injection in patients with Kellgren-Lawrence (KL) knee OA grades 2 to 4 in parallel single-arm trials.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A total of 80 patients were enrolled, with 42 (72 knees) receiving ASC intra-articular injection and 38 (69 knees) receiving SVF. Patient-reported outcome measures were assessed at 1, 3, 6, 12, and 24 months using the Knee injury and Osteoarthritis Outcome Score 5 (KOOS5) and pain visual analog scale (VAS). The percentages of patients achieving the minimal clinically important difference (MCID) and Patient Acceptable Symptom State (PASS) were also calculated. Per protocol, a subset of the ASC group received an ASC booster injection after 6 months. A repeated-measures analysis of variance compared results between treatment arms and by KL grade over time.

RESULTS

Patient-reported outcome measures improved substantially after both treatments (P < .05 at all time points), with the ASC group more likely to achieve the MCID (50% vs 24%; P = .01) and PASS (45% vs 24%; P = .04) for the pain VAS and the MCID (43% vs 16%; P = .02) for the KOOS5 at 12 months, although not at 24 months. Knees treated with ASC for KL grade 2/3 OA had significantly superior outcomes compared with those with KL grade 4 OA for the KOOS5 (P = .01) and pain VAS (P = .03), but no such difference was observed in knees treated with SVF. Three patients receiving ASCs (7%; all KL grade 3) sought additional nonoperative treatment by 24 months versus 9 patients receiving SVF (24%; all KL grade 3) (P = .06). ASC booster injections conferred no additional benefit. Notably, patients in the ASC cohort reported more injection-site pain and swelling after the booster injection than after the initial injection (P < .01).

CONCLUSION

This represents the first head-to-head comparison of ASCs and SVF for the treatment of knee OA in humans. ASC and SVF injections both substantially improved knee pain and function at all follow-up time points, although ASC injections demonstrated significantly better improvements with regard to the MCID and PASS for the pain VAS and the MCID for the KOOS5 at 12 months. There appears to be no benefit to a booster ASC injection after initial treatment. Given less donor-site morbidity and equivalent superior outcomes at 2 years, the use of ASCs over SVF in the treatment of knee OA may be warranted.

Osteoarthritis Pathophysiology: Therapeutic Target Discovery may Require a Multifaceted Approach

Molecular understanding of osteoarthritis (OA) has greatly increased through careful analysis of tissue samples, preclinical models, and large-scale agnostic "-omic" studies. There is broad acceptance that systemic and biomechanical signals affect multiple tissues of the joint, each of which could potentially be targeted to improve patient outcomes. In this review six experts in different aspects of OA pathogenesis provide their independent view on what they believe to be good tractable approaches to OA target discovery. We conclude that molecular discovery has been high but future transformative studies require a multidisciplinary holistic approach to develop therapeutic strategies with high clinical efficacy.

Association between knee symptoms, change in knee symptoms over 6-9 years, and SF-6D health state utility among middle-aged Australians

OBJECTIVES

Health state utilities (HSUs) are an input metric for estimating quality-adjusted life-years (QALY) in cost-utility analyses. Currently, there is a paucity of data on association of knee symptoms with HSUs for middle-aged populations. We aimed to describe the association of knee symptoms and change in knee symptoms with SF-6D HSUs and described the distribution of HSUs against knee symptoms' severity.

METHODS

Participants (36-49-years) were selected from the third follow-up (completed 2019) of Australian Childhood Determinants of Adult Health study. SF-6D HSUs were generated from the participant-reported SF-12. Association between participant-reported WOMAC knee symptoms' severity, change in knee symptoms over 6-9 years, and HSUs were evaluated using linear regression models.

RESULTS

For the cross-sectional analysis, 1,567 participants were included; mean age 43.5 years, female 54%, BMI ± SD 27.18 ± 5.31 kg/m². Mean ± SD HSUs for normal, moderate, and severe WOMAC scores were 0.820 ± 0.120, 0.800 ± 0.120, and 0.740 ± 0.130, respectively. A significant association was observed between worsening knee symptoms and HSUs in univariable and multivariable analyses after adjustment (age and sex). HSU decrement for normal-to-severe total-WOMAC and WOMAC-pain was - 0.080 (95% CI - 0.100 to - 0.060, p < 0.01) and - 0.067 (- 0.085 to - 0.048, p < 0.01), exceeding the mean minimal clinically important difference (0.04). Increase in knee pain over 6-9 years was associated with a significant reduction in HSU.

CONCLUSION

In a middle-aged population-based sample, there was an independent negative association between worse knee symptoms and SF-6D HSUs. Our findings may be used by decision-makers to define more realistic and conservative baseline and ongoing HSU values when assessing QALY changes associated with osteoarthritis interventions.

Metabolic signatures of osteoarthritis in urine using liquid chromatography-high resolution tandem mass spectrometry

INTRODUCTION

Osteoarthritis (OA) is a common cause of disability in older people, but its aetiology is not yet fully understood. Biomarkers of OA from metabolomics studies have shown potential use in understanding the progression and pathophysiology of OA.

OBJECTIVES

To investigate possible surrogate biomarkers of knee OA in urine using metabolomics to contribute towards a better understanding of OA progression and possible targeted treatment.

METHOD

Liquid chromatography-high resolution mass spectrometry (LC-HRMS) was applied in a case-control approach to explore the possible metabolic differences between the urinary profiles of symptomatic knee OA patients (n = 74) (subclassified into inflammatory OA, n = 22 and non-inflammatory OA, n = 52) and non-OA controls (n = 68). Univariate, multivariate and pathway analyses were performed with a rigorous validation including cross-validation, permutation test, prediction and receiver operating characteristic curve to identify significantly altered metabolites and pathways in OA.

RESULTS

OA datasets generated 7405 variables and multivariate analysis showed clear separation of inflammatory OA, but not non-inflammatory OA, from non-OA controls. Adequate cross-validation (R²Y = 0.874, Q² = 0.465) was obtained. The prediction model and the ROC curve showed satisfactory results with a sensitivity of 88%, specificity of 71% and accuracy of 77%. 26 metabolites were identified as potential biomarkers of inflammatory OA using HMDB, authentic standards and/or MS/MS database.

CONCLUSION

Urinary metabolic profiles were altered in inflammatory knee OA subjects compared to those with non-inflammatory OA and non-OA controls. These altered profiles associated with perturbed activity of the TCA cycle, pyruvate and amino acid metabolism linked to inflammation, oxidative stress and collagen destruction. Of note, 2-keto-glutaramic acid level was > eightfold higher in the inflammatory OA patients compared to non-OA control, signalling a possible perturbation in glutamine metabolism related to OA progression.

Low adherence to exercise may have influenced the proportion of OMERACT-OARSI responders in an integrated osteoarthritis care model: secondary analyses from a cluster-randomised stepped-wedge trial

BACKGROUND

To address the well-documented gap between hip and knee osteoarthritis (OA) treatment recommendations and current clinical practice, a structured model for integrated OA care was developed and evaluated in a stepped-wedge cluster-randomised controlled trial. The current study used secondary outcomes to evaluate clinically important response to treatment through the Outcome Measures in Rheumatology Clinical Trials clinical responder criteria (OMERACT-OARSI responder criteria) after 3 and 6 months between patients receiving the structured OA care model vs. usual care. Secondly, the study aimed to investigate if the proportion of responders in the intervention group was influenced by adherence to the exercise program inherent in the model.

METHODS

The study was conducted in primary healthcare in six Norwegian municipalities. General practitioners and physiotherapists received training in OA treatment recommendations and use of the structured model. The intervention group attended a physiotherapist-led OA education program and performed individually tailored exercises for 8-12 weeks. The control group received usual care. Patient-reported pain, function and global assessment of disease activity during the last week were evaluated using 11-point numeric rating scales (NRS 0-10). These scores were used to calculate the proportion of OMERACT-OARSI responders. Two-level mixed logistic regression models were fitted to investigate differences in responders between the intervention and control group.

RESULTS

Two hundred eighty-four intervention and 109 control group participants with hip and knee OA recruited from primary care in six Norwegian municipalities. In total 47% of the intervention and 35% of the control group participants were responders at 3 or 6 months combined; showing an uncertain between-group difference (OR_adjusted 1.38 (95% CI 0.41, 4.67). In the intervention group, 184 participants completed the exercise programme (exercised ≥2 times/week for ≥8 weeks) and 55% of these were classified as responders. In contrast, 28% of the 86 non-completers were classified as responders.

CONCLUSIONS

The difference in proportion of OMERACT-OARSI responders at 3 and 6 months between the intervention and control group was uncertain. In the intervention group, a larger proportion of responders were seen among the exercise completers compared to the non-completers.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT02333656. Registered 7. January 2015.