Exploring translational gaps between basic scientists, clinical researchers, clinicians, and consumers: Proceedings and recommendations arising from the 2020 mine the gap online workshop.

Objective: To provide a summary of the translational gaps in musculoskeletal research as identified in the Mine the Gap workshop and propose possible solutions. Methods: The Mine the Gap online workshop was hosted on October 14th and 15th, 2020. Five international panels, each comprised of a clinician, clinical researcher and basic scientist, presented gaps and proposed solutions for the themes of biomechanics, pain, biological measurements, phenotypes and imaging. This was followed by an interactive panel discussion with consumer insights. Results: A number of translational gaps and proposed solutions across each of the five themes were identified. A consumer panel provided constructive feedback highlighting the need for improved resources, communication and shared decision making, and treatment individualisation. Conclusion: This brief report provides a greater understanding of the diverse work and gaps relevant to fundamental/discovery scientists, clinical researchers and clinicians working across the musculoskeletal field. The numerous translational gaps highlight the need to improve communication and collaboration across the musculoskeletal field.

Corrigendum to "Exploring translational gaps between basic scientists, clinical researchers, clinicians, and consumers: Proceedings and recommendations arising from the 2020 mine the gap online workshop" [Osteoarthritis Cartilage Open 29 (2021) 100163].

[This corrects the article DOI: 10.1016/j.ocarto.2021.100163.].

The relationship between synovial inflammation, structural pathology, and pain in post-traumatic osteoarthritis: differential effect of stem cell and hyaluronan treatment.

BACKGROUND: Synovitis is implicated in the severity and progression of pain and structural pathology of osteoarthritis (OA). Increases in inflammatory or immune cell subpopulations including macrophages and lymphocytes have been reported in OA synovium, but how the particular subpopulations influence symptomatic or structural OA disease progression is unclear. Two therapies, hyaluronan (HA) and mesenchymal stem cells (MSCs), have demonstrated efficacy in some clinical settings: HA acting as device to improve joint function and provide pain relief, while MSCs may have immunomodulatory and disease-modifying effects. We used these agents to investigate whether changes in pain sensitization or structural damage were linked to modulation of the synovial inflammatory response in post-traumatic OA. METHODS: Skeletally mature C57BL6 male mice underwent medial-meniscal destabilisation (DMM) surgery followed by intra-articular injection of saline, a hyaluronan hexadecylamide derivative (Hymovis), bone marrow-derived stem cells (MSCs), or MSC + Hymovis. We quantified the progression of OA-related cartilage, subchondral bone and synovial histopathology, and associated pain sensitization (tactile allodynia). Synovial lymphocytes, monocyte/macrophages and their subpopulations were quantified by fluorescent-activated cell sorting (FACS), and the expression of key inflammatory mediators and catabolic enzyme genes quantified by real-time polymerase chain reaction (PCR). RESULTS: MSC but not Hymovis significantly reduced late-stage (12-week post-DMM) cartilage proteoglycan loss and structural damage. Allodynia was initially reduced by both treatments but significantly better at 8 and 12 weeks by Hymovis. Chondroprotection by MSCs was not associated with specific changes in synovial inflammatory cell populations but rather regulation of post-injury synovial Adamts4, Adamts5, Mmp3, and Mmp9 expression. Reduced acute post-injury allodynia with all treatments coincided with decreased synovial macrophage and T cell numbers, while longer-term effect on pain sensitization with Hymovis was associated with increased M2c macrophages. CONCLUSIONS: This therapeutic study in mice demonstrated a poor correlation between cartilage, bone or synovium (histo)pathology, and pain sensitization. Changes in the specific synovial inflammatory cell subpopulations may be associated with chronic OA pain sensitization, and a novel target for symptomatic treatment.

Dietary supplements for treating osteoarthritis: a systematic review and meta-analysis.

OBJECTIVE: To investigate the efficacy and safety of dietary supplements for patients with osteoarthritis. DESIGN: An intervention systematic review with random effects meta-analysis and meta-regression. DATA SOURCES: MEDLINE, EMBASE, Cochrane Register of Controlled Trials, Allied and Complementary Medicine and Cumulative Index to Nursing and Allied Health Literature were searched from inception to April 2017. STUDY ELIGIBILITY CRITERIA: Randomised controlled trials comparing oral supplements with placebo for hand, hip or knee osteoarthritis. RESULTS: Of 20 supplements investigated in 69 eligible studies, 7 (collagen hydrolysate, passion fruit peel extract, Curcuma longa extract, Boswellia serrata extract, curcumin, pycnogenol and L-carnitine) demonstrated large (effect size >0.80) and clinically important effects for pain reduction at short term. Another six (undenatured type II collagen, avocado soybean unsaponifiables, methylsulfonylmethane, diacerein, glucosamine and chondroitin) revealed statistically significant improvements on pain, but were of unclear clinical importance. Only green-lipped mussel extract and undenatured type II collagen had clinically important effects on pain at medium term. No supplements were identified with clinically important effects on pain reduction at long term. Similar results were found for physical function. Chondroitin demonstrated statistically significant, but not clinically important structural improvement (effect size -0.30, -0.42 to -0.17). There were no differences between supplements and placebo for safety outcomes, except for diacerein. The Grading of Recommendations Assessment, Development and Evaluation suggested a wide range of quality evidence from very low to high. CONCLUSIONS: The overall analysis including all trials showed that supplements provided moderate and clinically meaningful treatment effects on pain and function in patients with hand, hip or knee osteoarthritis at short term, although the quality of evidence was very low. Some supplements with a limited number of studies and participants suggested large treatment effects, while widely used supplements such as glucosamine and chondroitin were either ineffective or showed small and arguably clinically unimportant treatment effects. Supplements had no clinically important effects on pain and function at medium-term and long-term follow-ups.

Cartilage MicroRNA Dysregulation During the Onset and Progression of Mouse Osteoarthritis Is Independent of Aggrecanolysis and Overlaps With Candidates From End-Stage Human Disease.

OBJECTIVE: To identify candidate microRNAs (miRNAs) that potentially regulate the initiation and progression of osteoarthritis (OA). METHODS: OA was induced in 10-12-week-old male wild-type C57BL/6 mice and in mice resistant to aggrecanase cleavage (Acan p.374ALGS→374NVYS) by destabilization of the medial meniscus (DMM). Pathologic changes of OA were scored histologically. RNA from cartilage and subchondral bone was harvested in parallel by laser microdissection at 1 week and 6 weeks postsurgery. Global miRNA expression profiling was performed using Agilent microarrays and was validated by quantitative polymerase chain reaction analysis. RESULTS: Wild-type DMM mice had characteristic cartilage degeneration, subchondral bone sclerosis, and osteophyte formation. While no miRNA dysregulation was seen in subchondral bone, 139 miRNAs were differentially expressed in cartilage obtained at 1 and/or 6 weeks after OA initiation from wild-type mice that underwent DMM. To prioritize OA candidates, dysregulated miRNAs with human orthologs were filtered, and paired miRNA/messenger RNA (mRNA) expression analysis was conducted to identify those with corresponding changes in mRNA target transcripts in the DMM mouse cartilage. An important cohort also overlapped with miRNAs identified in human end-stage OA. Comparisons of miRNA dysregulation in DMM mouse cartilage where aggrecan cleavage was genetically ablated demonstrated that all candidates were independent of aggrecan breakdown, earmarking these as important to the critical stages of OA initiation. Furthermore, functional enrichment analysis and data annotation revealed the responses to mechanical stimuli, apoptotic processes, and core extracellular matrix structural and regulatory factors to be potentially influenced by OA-dysregulated miRNA/mRNA networks. CONCLUSION: Our comprehensive analyses identified high-priority miRNA candidates that have potential as biomarkers and therapeutic targets in human OA.

Comprehensive Expression Analysis of microRNAs and mRNAs in Synovial Tissue from a Mouse Model of Early Post-Traumatic Osteoarthritis.

To better understand the molecular processes involved in driving osteoarthritis disease progression we characterized expression profiles of microRNAs (miRNA) and mRNAs in synovial tissue from a post-traumatic OA mouse model. OA was induced in 10-12 week old male C57BL6 mice by bilateral surgical destabilization of the medial meniscus (DMM). RNA isolated from the anterior synovium of mice at 1 and 6 weeks post-surgery was subject to expression profiling using Agilent microarrays and qPCR. OA severity was determined histologically. Anterior and posterior synovitis decreased with post-operative time after sham and DMM. No differences in synovitis parameters were evident between sham and DMM in the anterior synovium at either time. While expression profiling revealed 394 miRNAs were dysregulated between 1 and 6 week time-points in the anterior synovium, there were no significant changes in miRNA or mRNA expression between DMM and sham mice at both time-points. Bioinformatic analysis of the miRNAs and mRNAs differentially expressed in tandem with the resolution of anterior synovial inflammation revealed similar biological processes and functions, including organismal injury, connective tissue disorder and inflammatory responses. Our data demonstrates that early OA-specific patterns of synovial miRNAs or mRNAs dysregulation could not be identified in this model of post-traumatic OA.

Altered stress induced by partial transection of the infraspinatus tendon leads to perlecan (HSPG2) accumulation in an ovine model of tendinopathy.

Perlecan is a widely distributed, heparan sulphate proteoglycan with roles in the sequestration of FGFs, PDGF, VEGF through which it promotes cell proliferation and matrix production. Perlecan also stabilises extracellular matrices through interaction with a diverse range of matrix components. This study examined the distribution of perlecan in an ovine partial transection tendinopathy model. In normal tendon, perlecan was immunolocalised to small blood vessels in intrafascicular regions in the tendon-bone and muscle-tendon attachments and to linear arrays of oval shaped tenocytes in the tendon mid-region. Partial transection in the mid-tendon region significantly increased perlecan accumulation within the fascicles, in granulation tissue filling the transection site and in the tendon-bone and tendon-muscle attachments. The accumulation of perlecan in the transected tendon and its known roles in matrix stabilisation and cell proliferation indicate possible roles in tendon remodelling and repair. Perlecan domain-1 has been used as a growth factor delivery vehicle for FGF-2, BMP-2 and BMP-7 in regenerative medicine but has yet to be evaluated in infraspinatus tendon repair. A better understanding of perlecan's contributions to pathobiological processes in remodelling tendon may be useful in such regenerative strategies in the future.