Anticytokine therapy for osteoarthritis

Autologous Protein Solution (APS) and Osteoarthritis of the Knee: A Scoping Review of Current Clinical Evidence

Knees are the most regularly affected weight-bearing joints in osteoarthritis (OA), impacting millions of individuals across the globe. The incidence of knee OA will further rise with increasing rates of obesity and lifespan, resulting in a significant increase in the worldwide socioeconomic burden. Conventional therapies used to manage the symptoms associated with knee OA have limitations. Lately, there has been an increased interest in the use of autologous peripheral blood-derived orthobiologics (APBO), including autologous protein solution (APS), for the management of knee OA. Here, the primary objective is to summarize the outcomes of clinical studies involving APS for the treatment of knee OA. Several databases (Embase, Scopus, PubMed, and Web of Science) were searched using terms for the intervention "APS" and treatment "knee OA" for articles published in English until January 21, 2024. All clinical studies using APS as an intervention for the treatment of knee OA were included. Studies not utilizing APS alone or not aiming at the management of knee OA were excluded. Six clinical studies that met our predefined search terms and inclusion and exclusion criteria were included in this study. The results demonstrated that the intra-articular administration of APS is safe and efficacious in reducing pain and/or improving function in patients suffering from knee OA. However, more multicenter, randomized controlled trials involving active comparators, with adequate power and long-term follow-up along with post-market real-world studies in clinical practice are required to further assess the efficacy of APS and justify its regular clinical use for the management of knee OA.

Comparisons of Cytokines, Growth Factors and Clinical Efficacy between Platelet-Rich Plasma and Autologous Conditioned Serum for Knee Osteoarthritis Management

This study aimed to directly compare the contents and the clinical efficacy of the two autologous blood-derived products, platelet-rich plasma (PRP) and autologous conditioned serum (ACS) for osteoarthritis (OA) treatment. The contents of standard-prepared PRP and ACS prepared at 37 °C for 1 h, 3 h, 6 h, and 24 h from healthy volunteers were compared. The clinical efficacy of pain relief in patients with Stage III knee OA was evaluated by a patient-reported visual analog scale (VAS) pain rating. PDGF-BB levels in ACS 1 h were significantly higher than those in PRP, and the levels in ACS preparations remained stable. IGF-1 level of ACS 24 h showed a significant increase compared to those of other ACS preparations and PRP. ACS 3 h showed a turning of IL-1Ra level and revealed a time-dependent increase up to 24 h. ACS 6 h showed a turning increase in TNF-α levels. ACS 3 h was chosen for clinical comparison with PRP. The reduction in pain VAS in the ACS group was significantly more compared to those of the PRP group (p = 0.028). However, PRP showed significant earlier improvement (p < 0.001). Conclusion: ACS contained higher levels of PDGF-BB and IL-1Ra and provided better improvement in pain relief compared to PRP.

Transplantation of IL‑1β siRNA‑modified bone marrow mesenchymal stem cells ameliorates type II collagen‑induced rheumatoid arthritis in rats

Rheumatoid arthritis (RA) is a chronic autoimmune disease that causes erosion of articular cartilage and bone and has adverse effects on both patients and livestock animals. The aim of the present study was to investigate the role of interleukin-1β (IL-1β) in the pathogenesis of RA, and to further determine whether injection of IL-1β small interfering RNA (siRNA) or transplantation of IL-1β siRNA + bone marrow mesenchymal stem cells (BMSCs) can ameliorate RA in rats. A collagen-induced arthritis (CIA) rat model was established by injecting type II collagen for 4 weeks. Next, CIA rats were randomly divided into three groups and injected or transplanted with PBS, IL-1β siRNA and IL-1β siRNA + BMSCs for another 4 weeks. The CIA rat model was successfully established, as demonstrated by the higher toe swelling value, thymus and spleen/body weight, immobility time and serum IL-1β concentration, as well as lower body weight, climbing time and mRNA expression of programmed death-1 (PD-1), transforming growth factor-β1 (TGF-β1) and forkhead box protein 3 (Foxp3) in the spleen, compared with control rats. Furthermore, histopathology results demonstrated that joint swelling and redness were observed in the knee joints of CIA rats. H&E results revealed that CIA rats presented erosive destruction of the bone and ulceration of the articular cartilage. In addition, in vitro results demonstrated that IL-1β expression was successfully silenced after IL-1β siRNA transfection in lipopolysaccharide-stimulated BMSCs. When compared with the results of PBS rats, both IL-1β siRNA injection and IL-1β siRNA + BMSC transplantation significantly increased the body weight, climbing time and mRNA expression of PD-1, TGF-β1 and Foxp3 in the spleen, while significantly reduced the immobility time and serum IL-1β concentration. In addition, when compared with that of IL-1β siRNA injection, IL-1β siRNA + BMSC transplantation exhibited markedly higher therapeutic efficacy against CIA. These results demonstrated that higher IL-1β contributed to the pathogenesis of CIA, and that IL-1β siRNA injection ameliorated CIA, while its combination with BMSCs exerted synergistic effects, which may be beneficial against RA.

Topical corticosteroid for treatment of hand osteoarthritis: study protocol for a randomised controlled trial

Background

Hand osteoarthritis is a common and disabling chronic joint disease with a lack of effective therapies. Emerging evidence suggests the role of local inflammation in causing pain in hand osteoarthritis. Corticosteroids are potent anti-inflammatory drugs used in many rheumatic diseases. The aim of this randomised, double-blind, placebo-controlled trial is to determine whether topical corticosteroid reduces pain over 6 weeks in patients with hand osteoarthritis.

Methods

One hundred participants with hand osteoarthritis will be recruited from the community in Melbourne, Australia, and randomly allocated in a 1:1 ratio to receive either topical Diprosone OV or placebo ointment administered 3 times daily on the painful hand joints for 6 weeks. The primary outcome is pain reduction (assessed by 100 mm visual analogue scale) at 6 weeks. The secondary outcomes include changes in pain and function assessed using Functional Index for Hand Osteoarthritis, Australian Canadian Osteoarthritis Hand Index, Michigan Hand Outcomes Questionnaire, and tender and swollen joint count at 6 weeks. Adverse events will be recorded. The primary analysis will be by intention to treat, including all participants in their randomised groups.

Discussion

This study will provide high-quality evidence to determine whether topical corticosteroid reduces pain over 6 weeks in patients with hand osteoarthritis, with major clinical and public health importance by informing clinical practice guidelines for the management of hand osteoarthritis and reducing the burden of the disabling disease.

Trial registration

Australian New Zealand Clinical Trials Registry (ANZCTR), ACTRN12620000599976. Registered 22 May 2020.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04921-2.

METHODS - A randomised controlled trial of METhotrexate to treat Hand Osteoarthritis with Synovitis: study protocol for a randomised controlled trial

Background

Hand osteoarthritis is a common and disabling problem without effective therapies. Accumulating evidence suggests the role of local inflammation in causing pain and structural progression in hand osteoarthritis, and hand osteoarthritis with synovitis is a commonly encountered clinical phenotype. Methotrexate is a well-established, low-cost, and effective treatment for inflammatory arthritis with a well-described safety profile. The aim of this multicentre, randomised, double-blind, placebo-controlled trial is to determine whether methotrexate reduces pain over 6 months in patients with hand osteoarthritis and synovitis.

Methods

Ninety-six participants with hand osteoarthritis and synovitis will be recruited through the Osteoarthritis Clinical Trial Network (Melbourne, Hobart, Adelaide, and Perth), and randomly allocated in a 1:1 ratio to receive either methotrexate 20 mg or identical placebo once weekly for 6 months. The primary outcome is pain reduction (assessed by 100 mm visual analogue scale) at 6 months. The secondary outcomes include changes in physical function and quality of life assessed using Functional Index for Hand Osteoarthritis, Australian Canadian Osteoarthritis Hand Index, Health Assessment Questionnaire, Michigan Hand Outcomes Questionnaire, Short-Form-36, tender and swollen joint count, and grip strength, and structural progression assessed using progression of synovitis and bone marrow lesions from magnetic resonance imaging and radiographic progression at 6 months. Adverse events will be recorded. The primary analysis will be by intention to treat, including all participants in their randomised groups.

Discussion

This study will provide high-quality evidence to address whether methotrexate has an effect on reducing pain over 6 months in patients with hand osteoarthritis and synovitis, with major clinical and public health importance. While a positive trial will inform international clinical practice guidelines for the management of hand osteoarthritis, a negative trial would be highly topical and change current trends in clinical practice.

Trial registration

Australian New Zealand Clinical Trials Registry (ANZCTR), ACTRN12617000877381. Registered 15 June 2017, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=373124

Autologous protein solution: a promising solution for osteoarthritis?

Osteoarthritis (OA) is a global health issue with myriad pathophysiological factors and is one of the most common causes of chronic disability in adults due to pain and altered joint function.

The end stage of OA develops from a destructive inflammatory cycle, driven by the pro-inflammatory cytokines interleukin-1β (IL-1β) and tumour necrosis factor alpha (TNFα).

Owing to the less predictable results of total knee arthroplasty (TKA) in younger patients presenting with knee OA, there has been a surge in research evaluating less invasive biological treatment options, one of which is autologous protein solution (APS).

APS is an autologous blood derivative obtained by using a proprietary device, made of APS separator, which isolates white blood cells (WBCs) and platelets in a small volume of plasma, and APS concentrator, which further concentrates platelets, WBCs and plasma proteins, resulting in a concentrated solution with high levels of growth factors including the anti-inflammatory mediators against IL-1β and TNFα.

A single intraarticular injection of APS appears to be a promising solution for treatment of early-stage OA from current evidence, the majority of which comes from preclinical studies.

More clinical studies are needed before APS can be widely accepted as a treatment modality for OA.

Cite this article: EFORT Open Rev 2021;6:716-726. DOI: 10.1302/2058-5241.6.200040

Prospects for Therapies in Osteoarthritis

Osteoarthritis (OA) is a chronic, debilitating disease affecting millions of people worldwide. Management of OA involves pharmacological and non-pharmacological approaches. Conventional pharmacological treatments have limited efficacy and are associated with a number of side-effects, restricting the number of patients who can use them. New pharmacological therapies for managing OA are required and a number have been developed targeting different tissues in OA: bone and cartilage, synovium and nerves. However, there has been overall limited success. Disease-modifying osteoarthritis drugs (DMOADs) are a putative class of therapies aimed at improving OA structural pathologies and consequent symptoms. Recent DMOAD studies have demonstrated some promising therapies but also provided new considerations for future trials.

Efficacy of Methotrexate on Rat Knee Osteoarthritis Induced by Monosodium Iodoacetate

Objective

To explore whether methotrexate (MTX) prevents joint destruction and improves pain-related behaviors in the acute phase of knee osteoarthritis (OA) induced by monosodium iodoacetate (MIA) in a rat model.

Methods

Twenty of 25 male Wistar rats (10–14 weeks old) received 3 mg MIA via intra-articular injection into their right knee and were then administered a vehicle control (n=10) or 3 mg/kg MTX orally weekly (n=10). We assessed differences in pain-related behavior, spontaneous lifting behavior, micro-computed tomography (CT), histopathology, and expression of pain- and inflammatory-related genes using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) between the two groups for 4 weeks. Five rats were used as untreated controls to assess pain- and inflammatory-related mRNA expression in the dorsal root ganglia (DRG) and knee joints using RT-qPCR.

Results

Joint destruction and mechanical hyperalgesia were observed in the vehicle group. Decreases in mechanical pain thresholds for the knee joint and calf muscles were improved after MTX administration; however, joint damage assessed by micro-CT and histopathology was not significantly inhibited by MTX administration, while upregulation levels of transient receptor potential cation channel, subfamily V, member 1 (TRPV-1) (P<0.01) and brain-derived neurotrophic factor (BDNF) (P=0.02) mRNA in the DRG and nerve growth factor NGF mRNA (P=0.03) in the affected knee joints were significantly suppressed in the MTX group compared with the vehicle group at week 4.

Conclusion

Our results imply that MTX administration improves pain-related behaviors and suppresses expression of pain-related mRNAs in the DRG and knee joint; however, MTX is not expected to prevent cartilage degeneration in MIA-induced OA in rat knee.

Deep-Sea Coral Garden Invertebrates and Their Associated Fungi Are Genetic Resources for Chronic Disease Drug Discovery

Chronic diseases characterized by bone and cartilage loss are associated with a reduced ability of progenitor cells to regenerate new tissues in an inflammatory environment. A promising strategy to treat such diseases is based on tissue repair mediated by human mesenchymal stem cells (hMSCs), but therapeutic outcomes are hindered by the absence of small molecules to efficiently modulate cell behaviour. Here, we applied a high-throughput drug screening technology to bioprospect a large library of extracts from Irish deep-sea organisms to induce hMSC differentiation toward musculoskeletal lineages and reduce inflammation of activated macrophages. The library included extracts from deep-sea corals, sponges and filamentous fungi representing a novel source of compounds for the targeted bioactivity. A validated hit rate of 3.4% was recorded from the invertebrate library, with cold water sea pens (octocoral order Pennatulacea), such as Kophobelemnon sp. and Anthoptilum sp., showing the most promising results in influencing stem cell differentiation toward osteogenic and chondrogenic lineages. Extracts obtained from deep-sea fungi showed no effects on stem cell differentiation, but a 6.8% hit rate in reducing the inflammation of activated macrophages. Our results demonstrate the potential of deep-sea organisms to synthetize pro-differentiation and immunomodulatory compounds that may represent potential drug development candidates to treat chronic musculoskeletal diseases.

The Development of Disease-Modifying Therapies for Osteoarthritis (DMOADs): The Evidence to Date

Osteoarthritis (OA) is a complex heterogeneous articular disease with multiple joint tissue involvement of varying severity and no regulatory-agency-approved disease-modifying drugs (DMOADs). In this review, we discuss the reasons necessitating the development of DMOADs for OA management, the classifications of clinical phenotypes or molecular/mechanistic endotypes from the viewpoint of targeted drug discovery, and then summarize the efficacy and safety profile of a range of targeted drugs in Phase 2 and 3 clinical trials directed to cartilage-driven, bone-driven, and inflammation-driven endotypes. Finally, we briefly put forward the reasons for failures in OA clinical trials and possible steps to overcome these barriers.

Methotrexate treatment in hand osteoarthritis refractory to usual treatments: A randomised, double-blind, placebo-controlled trial

OBJECTIVE

To examine the effect of methotrexate (MTX) on pain and structural progression in symptomatic erosive hand osteoarthritis (HOA).

METHODS

This 1-year prospective, single-centre, randomised, double-blind, placebo-controlled study (www.ClinicalTrial.gov, NCT01068405) followed up patients with symptomatic erosive HOA. Patients were randomised into two groups based on the drug that was administered: 10 mg methotrexate (MTX) per week or a placebo. The primary endpoint was the change in pain (determined using a visual analogue scale [VAS]) from baseline to 3 months. The secondary endpoints were pain VAS score at 12 months, clinical features (pain VAS score and function), radiographic features (the anatomical radiographic Verbruggen-Veys [VV] score and Gent University Score System), and magnetic resonance imaging (MRI) at 12 months.

RESULTS

Sixty-four patients with HOA were randomised into either the placebo or MTX group. At 3 months, there was no significant difference in the mean decrease in the pain VAS score (mm) (MTX: 21.1 [standard deviation, 27.4], placebo: 11.7 [24.3]; p = 0.2). At 12 months, according to the VV score, erosive joints progressed significantly more to a remodelling phase in the MTX group than in the placebo group (27% vs 15%; p = 0.03). Joints with space loss appeared to be eroding less in the MTX group compared to the placebo group (8% vs 29%; p = 0.2). Synovitis on MRI at baseline could be associated with the erosive structural evolution of non-erosive joints (p = 0.02).

CONCLUSIONS

Weekly doses of 10-mg MTX showed no superiority over the placebo in terms of pain relief at 3 or 12 months.

CLINICAL TRIAL REGISTRATION NUMBER

This study was registered at www.ClinicalTrial.gov (NCT01068405).

A chondroprotective effect of moracin on IL-1β-induced primary rat chondrocytes and an osteoarthritis rat model through Nrf2/HO-1 and NF-κB axes

Osteoarthritis (OA) is a common joint disease characterized by cartilage degeneration and inflammation. Although moracin is known to play a role in anti-inflammation and anti-oxidation in several inflammatory diseases, its anti-inflammatory effect on OA remains largely unknown. Therefore, in order to explore the role of moracin in OA, we investigated the anti-inflammatory effect of moracin on interleukin (IL)-β-induced rat chondrocytes in vitro and surgically induced OA rat models in vivo. Rat chondrocytes were pretreated using moracin (0, 5, 10, 15 μmol L-1) and then stimulated with IL-β (10 ng ml-1). Results showed that moracin reduced the expression of IL-1β-induced nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α), IL-6, inducible nitric oxide synthase (iNOS), and cyclooxygenase (COX)-2 in both rat chondrocytes and cell culture supernatants. Besides, IL-1β-induced degradation of aggrecan and collage II, and the high expression of matrix metalloproteinase-13 (MMP-13) and a disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS)-5 were also reversed by moracin. Moreover, moracin inhibited the translocation of p65 from the cytoplasm to nucleus induced by IL-1β and activated the Nrf2/HO-1 signaling pathway in chondrocytes. In OA rat models, moracin prevented cartilage of rats from destruction. All these findings above indicated that moracin could be a potentially effective drug for treating OA.

Cathepsin g Degrades Both Glycosylated and Unglycosylated Regions of Lubricin, a Synovial Mucin

Lubricin (PRG4) is a mucin type protein that plays an important role in maintaining normal joint function by providing lubrication and chondroprotection. Improper lubricin modification and degradation has been observed in idiopathic osteoarthritis (OA), while the detailed mechanism still remains unknown. We hypothesized that the protease cathepsin G (CG) may participate in degrading lubricin in synovial fluid (SF). The presence of endogenous CG in SF was confirmed in 16 patients with knee OA. Recombinant human lubricin (rhPRG4) and native lubricin purified from the SF of patients were incubated with exogenous CG and lubricin degradation was monitored using western blot, staining by Coomassie or Periodic Acid-Schiff base in gels, and with proteomics. Full length lubricin (∼300 kDa), was efficiently digested with CG generating a 25-kDa protein fragment, originating from the densely glycosylated mucin domain (∼250 kDa). The 25-kDa fragment was present in the SF from OA patients, and the amount was increased after incubation with CG. A CG digest of rhPRG4 revealed 135 peptides and 72 glycopeptides, and confirmed that the protease could cleave in all domains of lubricin, including the mucin domain. Our results suggest that synovial CG may take part in the degradation of lubricin, which could affect the pathological decrease of the lubrication in degenerative joint disease.

Exosomes from adipose‑derived stem cells promote chondrogenesis and suppress inflammation by upregulating miR‑145 and miR‑221

Osteoarthritis (OA) is one of the most prevalent joint disorders globally. Patients suffering from OA are often obese and adiposity is linked to chronic inflammation. In the present study, the potential of using exosomes isolated from adipose‑derived stem cells (ADSCs) as a therapeutic tool for reducing chronic inflammation and promoting chondrogenesis was investigated using patient‑derived primary cells. First, it was tested whether patient‑derived ADSCs could differentiate into chondrogenic and osteogenic lineages. The ADSCs were then used as a source of exosomes. It was found that exosomes isolated from ADSCs, when co‑cultured with activated synovial fibroblasts, downregulated the expression of pro‑inflammatory markers interleukin (IL)‑6, NF‑κB and tumor necrosis factor‑α, while they upregulated the expression of the anti‑inflammatory cytokine IL‑10; without exosomes, the opposite observations were made. In addition, inflammation‑inflicted oxidative stress was induced in vitro by stimulating chondrocytes with H2O2. Treatment with exosomes protected articular chondrocytes from H2O2‑induced apoptosis. Furthermore, exosome treatment promoted chondrogenesis in periosteal cells and increased chondrogenic markers, including Collagen type II and β‑catenin; inhibition of Wnt/β‑catenin, using the antagonist ICG‑001, prevented exosome‑induced chondrogenesis. Periosteal cells treated with exosomes exhibited higher levels of microRNA (miR)‑145 and miR‑221. The upregulation of miR‑145 and miR‑221 was associated with the enhanced proliferation of periosteal cells and chondrogenic potential, respectively. The present study provided evidence in support for the use of patient‑derived exosomes, produced from ADSCs, for potential chondrogenic regeneration and subsequent amelioration of osteoarthritis.

Human Synovia Contains Trefoil Factor Family (TFF) Peptides 1-3 Although Synovial Membrane Only Produces TFF3: Implications in Osteoarthritis and Rheumatoid Arthritis

Objective: Trefoil factor family peptide 3 (TFF3) has been shown to support catabolic functions in cases of osteoarthritis (OA). As in joint physiology and diseases such as OA, the synovial membrane (SM) of the joint capsule also plays a central role. We analyze the ability of SM to produce TFF compare healthy SM and its secretion product synovial fluid (SF) with SM and SF from patients suffering from OA or rheumatoid arthritis (RA). Methods: Real-time PCR and ELISA were used to measure the expression of TFFs in healthy SM and SM from patients suffering from OA or RA. For tissue localization, we investigated TFF1-3 in differently aged human SM of healthy donors by means of immunohistochemistry, real-time PCR and Western blot. Results: Only TFF3 but not TFF1 and -2 was expressed in SM from healthy donors as well as cases of OA or RA on protein and mRNA level. In contrast, all three TFFs were detected in all samples of SF on the protein level. No significant changes were observed for TFF1 at all. TFF2 was significantly upregulated in RA samples in comparison to OA samples. TFF3 protein was significantly downregulated in OA samples in comparison to healthy samples and cases of RA significantly upregulated compared to OA. In contrast, in SM TFF3 protein was not significantly regulated. Conclusion: The data demonstrate the production of TFF3 in SM. Unexpectedly, SF contains all three known TFF peptides. As neither articular cartilage nor SM produce TFF1 and TFF2, we speculate that these originate with high probability from blood serum.

Update on novel pharmacological therapies for osteoarthritis

Osteoarthritis (OA) is a chronic painful arthritis with increasing global prevalence. Current management involves non-pharmacological interventions and commonly used pharmacological treatments that generally have limited analgesic efficacy and multiple side effects. New treatments are therefore required to relieve patient symptoms and disease impact. A number of existing pharmacological therapies have been recently trialled in OA. These include extended-release triamcinolone and conventional disease-modifying anti-rheumatic drugs (DMARDs) used in the management of rheumatoid arthritis; generally, DMARDs have not shown a benefit in treating OA. Novel analgesic therapies are in development, including those targeting peripheral pain pathways. Disease-modifying osteoarthritis drugs (DMOADs) target key tissues in the OA pathophysiology process and aim to prevent structural progression; a number of putative DMOADs are in phase II development. There is preliminary evidence of structural improvement with some of these therapies but without concomitant symptom improvement, raising new considerations for future DMOAD trials.

The Effect of Charge and Mechanical Loading on Antibody Diffusion Through the Articular Surface of Cartilage

Molecular transport of osteoarthritis (OA) therapeutics within articular cartilage is influenced by many factors, such as solute charge, that have yet to be fully understood. This study characterizes how solute charge influences local diffusion and convective transport of antibodies within the heterogeneous cartilage matrix. Three fluorescently tagged solutes of varying isoelectric point (pI) (4.7–5.9) were tested in either cyclic or passive cartilage loading conditions. In each case, local diffusivities were calculated based on local fluorescence in the cartilage sample, as observed by confocal microscopy. In agreement with past research, local solute diffusivities within the heterogeneous cartilage matrix were highest around 200–275 μm from the articular surface, but 3–4 times lower at the articular surface and in the deeper zones of the tissue. Transport of all 150 kDa solutes was significantly increased by the application of mechanical loading at 1 Hz, but local transport enhancement was not significantly affected by changes in solute isoelectric point. More positively charged solutes (higher pI) had significantly higher local diffusivities 200–275 μm from the tissue surface, but no other differences were observed. This implies that there are certain regions of cartilage that are more sensitive to changes in solute charge than others, which could be useful for future development of OA therapeutics.

Measurement of local diffusion and composition in degraded articular cartilage reveals the unique role of surface structure in controlling macromolecular transport

Developing effective therapeutics for osteoarthritis (OA) necessitates that such molecules can reach and target chondrocytes within articular cartilage. However, predicting how well very large therapeutic molecules diffuse through cartilage is often difficult, and the relationship between local transport mechanics for these molecules and tissue heterogeneities in the tissue is still unclear. In this study, a 150 kDa antibody diffused through the articular surface of healthy and enzymatically degraded cartilage, which enabled the calculation of local diffusion mechanics in tissue with large compositional variations. Local cartilage composition and structure was quantified with Fourier transform infrared (FTIR) spectroscopy and second harmonic generation (SHG) imaging techniques. Overall, both local concentrations of aggrecan and collagen were correlated to local diffusivities for both healthy and surface-degraded samples (0.3 > R² < 0.9). However, samples that underwent surface degradation by collagenase exhibited stronger correlations (R² > 0.75) compared to healthy samples (R² < 0.46), suggesting that the highly aligned collagen at the surface of cartilage acts as a barrier to macromolecular transport.

Cytokine-induced interleukin-1 receptor antagonist protein expression in genetically engineered equine mesenchymal stem cells for osteoarthritis treatment

BACKGROUND

A combination of tissue engineering methods employing mesenchymal stem cells (MSCs) together with gene transfer takes advantage of innovative strategies and highlights a new approach for targeting osteoarthritis (OA) and other cartilage defects. Furthermore, the development of systems allowing tunable transgene expression as regulated by natural disease-induced substances is highly desirable.

METHODS

Bone marrow-derived equine MSCs were transduced with a lentiviral vector expressing interleukin-1 receptor antagonist (IL-1Ra) gene under the control of an inducible nuclear factor-kappa B-responsive promoter and IL-1Ra production upon pro-inflammatory cytokine stimulation [tumor necrosis factor (TNF)α, interleukin (IL)-1β] was analysed. To assess the biological activity of the IL-1Ra protein that was produced and the therapeutic effect of IL-1Ra-expressing MSCs (MSC/IL-1Ra), cytokine-based two- and three-dimensional in vitro models of osteoarthritis using equine chondrocytes were established and quantitative real-time polymerase chain reaction (PCR) analysis was used to measure the gene expression of aggrecan, collagen IIA1, interleukin-1β, interleukin-6, interleukin-8, matrix metalloproteinase-1 and matrix metalloproteinase-13.

RESULTS

A dose-dependent increase in IL-1Ra expression was found in MSC/IL-1Ra cells upon TNFα administration, whereas stimulation using IL-1β did not lead to IL-1Ra production above the basal level observed in nonstimulated cells as a result of the existing feedback loop. Repeated cycles of induction allowed on/off modulation of transgene expression. In vitro analyses revealed that IL-1Ra protein present in the conditioned medium from MSC/IL-1Ra cells blocks OA onset in cytokine-treated equine chondrocytes and co-cultivation of MSC/IL-1Ra cells with osteoarthritic spheroids alleviates the severity of the osteoarthritic changes.

CONCLUSIONS

Thus, pro-inflammatory cytokine induced IL-1Ra protein expression from genetically modified MSCs might represent a promising strategy for osteoarthritis treatment.

Local intra‑articular injection of vascular endothelial growth factor accelerates articular cartilage degeneration in rat osteoarthritis model

In the pathophysiology of osteoarthritis (OA), articular cartilage degeneration exhibits a significant role. Vascular endothelial growth factor (VEGF) is considered to be an effective angiogenic factor and a crucial regulator of articular cartilage degeneration in the development of OA. Therefore, the present study aimed to investigate the underlying influences of exogenous VEGF on articular cartilage degeneration in OA model rat. A total of 24 male Sprague-Dawley rats were randomly allocated into 3 groups. In the normal saline (NS) and VEGF groups, animals received bilateral anterior cruciate ligament (ACL) transection to establish the OA model; at 4 weeks post-surgery, the rats received local intra-articular injections of 100 µl NS or VEGF solution, respectively, every week for 4 weeks. The Control group received neither surgery nor injections. All animals were sacrificed at 12 weeks following surgery. Prominent cartilage degeneration was observed in rats in the NS- and VEGF-injected groups. The extent and the grade of cartilage damage in the VEGF-injected group were notably more severe compared with those in the NS-treated group. Western blotting results demonstrated that the expression levels of aggrecan and type II collagen were significantly reduced in OA model rats that were treated with VEGF. In addition, the expression levels of matrix metalloproteinase (MMP)-3, MMP-9, MMP-13, a disintegrin and metalloproteinase with thrombospondin motifs (a disintegrin and metalloproteinase; ADAMTS)-4, −5 and −12, type III collagen and transforming growth factor-β1 were significantly increased following VEGF administration. Results from the present study indicated that VEGF may exhibit a promoting role in the development of OA by destroying articular cartilage matrix.

Human blood-based anti-inflammatory solution inhibits osteoarthritis progression in a meniscal-tear rat study

Current osteoarthritis (OA) research searches for treatments that modify the course of disease progression. Autologous Protein Solution (APS) is derived from whole blood and is a unique autologous therapy that contains high concentrations of white blood cells, platelets, and concentrated plasma, providing cytokines that can target the underlying mechanisms of disease progression. The APS Kit is currently under investigation for clinical use in the USA (NCT02262364). The aim of this study was to determine if APS has disease-modifying properties in the well-characterized rat meniscal tear-induced model of OA. Thirty male athymic rats underwent surgery to induce OA by a complete tear of the medial meniscus of the right knee. Seven days later, rats were administered 50 μl intra-articular (IA) APS from a human donor or phosphate buffered saline (PBS) control. Rats were euthanized 3 weeks following treatment and knee joints were processed for histological analysis. Collagen and cartilage degeneration were decreased by APS treatment, resulting in a significantly improved total joint score in APS-treated rats compared to those treated with the PBS control. No significant variations in gait analysis, weight gain, osteophyte score, or synovitis score were observed between APS- and PBS-treated animals. There were no adverse effects of APS reported in the study. Treatment with a single IA injection of APS reduced the cartilage degeneration that characterizes the progression of OA. Further studies are necessary to determine if APS can modify OA disease progression in humans. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2260-2268, 2017.

The Effect of Antibody Size and Mechanical Loading on Solute Diffusion Through the Articular Surface of Cartilage

Because of the heterogeneous nature of articular cartilage tissue, penetration of potential therapeutic molecules for osteoarthritis (OA) through the articular surface (AS) is complex, with many factors that affect transport of these solutes within the tissue. Therefore, the goal of this study is to investigate how the size of antibody (Ab) variants, as well as application of cyclic mechanical loading, affects solute transport within healthy cartilage tissue. Penetration of fluorescently tagged solutes was quantified using confocal microscopy. For all the solutes tested, fluorescence curves were obtained through the articular surface. On average, diffusivities for the solutes of sizes 200 kDa, 150 kDa, 50 kDa, and 25 kDa were 3.3, 3.4, 5.1, and 6.0 μm2/s from 0 to 100 μm from the articular surface. Diffusivities went up to a maximum of 16.5, 18.5, 20.5, and 23.4 μm2/s for the 200 kDa, 150 kDa, 50 kDa, and 25 kDa molecules, respectively, from 225 to 325 μm from the surface. Overall, the effect of loading was very significant, with maximal transport enhancement for each solute ranging from 2.2 to 3.4-fold near 275 μm. Ultimately, solutes of this size do not diffuse uniformly nor are convected uniformly, through the depth of the cartilage tissue. This research potentially holds great clinical significance to discover ways of further optimizing transport into cartilage and leads to effective antibody-based treatments for OA.

Insights on Molecular Mechanisms of Chondrocytes Death in Osteoarthritis

Osteoarthritis (OA) is a joint pathology characterized by progressive cartilage degradation. Medical care is mainly based on alleviating pain symptoms. Compelling studies report the presence of empty lacunae and hypocellularity in cartilage with aging and OA progression, suggesting that chondrocyte cell death occurs and participates to OA development. However, the relative contribution of apoptosis per se in OA pathogenesis appears complex to evaluate. Indeed, depending on technical approaches, OA stages, cartilage layers, animal models, as well as in vivo or in vitro experiments, the percentage of apoptosis and cell death types can vary. Apoptosis, chondroptosis, necrosis, and autophagic cell death are described in this review. The question of cell death causality in OA progression is also addressed, as well as the molecular pathways leading to cell death in response to the following inducers: Fas, Interleukin-1β (IL-1β), Tumor Necrosis factor-α (TNF-α), leptin, nitric oxide (NO) donors, and mechanical stresses. Furthermore, the protective role of autophagy in chondrocytes is highlighted, as well as its decline during OA progression, enhancing chondrocyte cell death; the transition being mainly controlled by HIF-1α/HIF-2α imbalance. Finally, we have considered whether interfering in chondrocyte apoptosis or promoting autophagy could constitute therapeutic strategies to impede OA progression.

Inhibition of microRNA-449a prevents IL-1β-induced cartilage destruction via SIRT1

OBJECTIVE

SIRT1 has anti-inflammatory as well as protective effects in chondrocytes. The object of this study was to investigate whether microRNA-449a regulates expression of SIRT1, which inhibits expression of catabolic genes in IL-1β-induced cartilage destruction.

MATERIALS AND METHODS

MicroRNA-449a expression was determined in OA chondrocytes and IL-1β-induced chondrocytes by real-time PCR. MicroRNA-449a binding sites on the 3'-UTR of SIRT1 mRNA and binding site conservation were examined using microRNA target prediction tools. SIRT1-overexpressing or knockdown chondrocytes were transfected with microRNA-449a or anti-microRNA-449a mimic and stimulated by IL-1β. Expression of catabolic and anabolic genes was examined by real-time PCR and western blotting. Finally, positive effects of anti-microRNA-449a on expression of these genes were confirmed by western analysis of OA chondrocytes.

RESULTS

Expression of microRNA-449a was increased in OA chondrocytes and IL-1β-induced chondrocytes. MMP-13 expression was enhanced, whereas type II collagen and SIRT1 expression were decreased in IL-1β-induced chondrocytes. SIRT1 overexpression resulted in decreased expression of catabolic genes such as MMPs and ADAMTSs in response to IL-1β, but these effects were moderated by microRNA-449a. Suppression of microRNA-449a by anti-microRNA-449a inhibited expression of catabolic genes despite IL-1β stimulation, but these effects were abolished in SIRT1 knockdown chondrocytes. Furthermore, expression of catabolic genes was decreased and expression of type II collagen as well as SIRT1 was restored by anti-microRNA-449a in OA chondrocytes as well as in IL-1β-induced chondrocytes.

CONCLUSION

Silencing of microRNA-449a had a protective effect, inhibiting catabolic gene expression and restoring anabolic gene expression, by targeting SIRT1 in IL-1β-induced cartilage destruction.

Interleukin-1 in Rheumatoid Arthritis: Its Inhibition by IL-1Ra and Anakinra

Objective:

To review the biology of interleukin-1 (IL-1) in the pathogenesis of rheumatoid arthritis (RA), as well as the biology of its natural inhibitor, IL receptor antagonist (IL-1Ra), and the clinical efficacy and safety of the recombinant form, anakinra.

Data Sources:

A MEDLINE search (1966–January 2007) of English-language articles was conducted using the key words anakinra, arthritis, clinical trial, interleukin-1 receptor antagonist, and Kineret.

Study Selection and Data Extraction:

Over 79 research articles and literature reviews were used to compile a discussion of the biology of IL-1 and IL-1Ra. Ten of these articles were selected to discuss the clinical safety and efficacy of anakinra.

Data Synthesis:

In RA, IL-1 primarily acts locally to mediate erosion of cartilage and bone. IL-1Ra serves to modulate its activity through competitive inhibition of cellular receptors. Administration of anakinra to animals with experimental arthritis reduced inflammation and joint damage. In clinical trials, anakinra was reasonably well tolerated; however, injection site reactions were frequent and there was a slight increased risk of serious infection. Alone or in combination with methotrexate, anakinra significantly reduced the symptoms and clinical signs of RA at the American College of Rheumatology 20% response level. However, no additive benefit was observed following coadministration with etanercept, a soluble tumor necrosis factor antagonist, and anakinra had no beneficial effect in patients that failed treatment with etanercept.

Conclusions:

Laboratory studies have indicated that IL-1 is primarily responsible for cartilage destruction and bone erosion in RA. The selective inhibition of IL-1 through administration of anakinra may offer symptomatic relief of RA in some patients.

Osteopontin as a biochemical marker and severity indicator for idiopathic hip osteoarthritis

INTRODUCTION

A diagnostic evaluation of the severity and progression of hip osteoarthritis (OA) using biochemical markers is lacking in the current medical literature. Osteopontin (OPN) has been proved to correlate with the progression and severity of knee OA. Therefore, the examination of plasma OPN levels in patients with idiopathic hip OA and its correlation with disease severity and progression was necessary.

METHODS

Our study included 21 patients displaying symptomatic severe idiopathic hip OA; the diagnosis of the disease was based on the checklist of the American College of Rheumatology and the severity was evaluated according to the K-L grading (Kellgran and Lawrence score).

RESULTS

14 patients showed radiological changes according K-L grade 3 (66.66%), and 7 patients showed radiological changes according K-L grade 4 (33.33%). We observed a highly statistically significant increase of plasma OPN levels in comparison with normal referenced values, the cut off value for differentiating between normal people and patients with hip OA was 193.6 ng/ml. Furthermore, the mean of plasma OPN levels in idiopathic hip osteoarthritis patients with K-L grade 4 (362.51 ± 83.31 ng/mL) was greater than those with K-L grade 3 (283.41 ± 56.31 ng/mL), the difference being statistically significant.

CONCLUSIONS

plasma OPN levels are increased in idiopathic hip OA and are correlated with the severity of the disease.

Altered joint tribology in osteoarthritis: Reduced lubricin synthesis due to the inflammatory process. New horizons for therapeutic approaches

Osteoarthritis (OA) is the most common form of joint disease. This review aimed to consolidate the current evidence that implicates the inflammatory process in the attenuation of synovial lubrication and joint tissue homeostasis in OA. Moreover, with these findings, we propose some evidence for novel therapeutic strategies for preventing and/or treating this complex disorder. The studies reviewed support that inflammatory mediators participate in the onset and progression of OA after joint injury. The flow of pro-inflammatory cytokines following an acute injury seems to be directly associated with altered lubricating ability in the joint tissue. The latter is associated with reduced level of lubricin, one of the major joint lubricants. Future research should focus on the development of new therapies that attenuate the inflammatory process and restore lubricin synthesis and function. This approach could support joint tribology and synovial lubrication leading to improved joint function and pain relief.

Interleukin-1β induces fibroblast growth factor 2 expression and subsequently promotes endothelial progenitor cell angiogenesis in chondrocytes

Angiogenesis is an important event in the process of arthritis. Stimulating chondrocytes with IL-1β increased the expression of FGF-2, via the IL-1RI/ROS/AMPK/p38/NF-κB signalling pathway. FGF-2-neutralizing antibody abolished ATDC5-conditional medium-mediated angiogenesis both in vitro and in vivo.

Arthritis is a process of chronic inflammation that results in joint damage. IL (interleukin)-1β is an inflammatory cytokine that acts as a key mediator of cartilage degradation, and is abundantly expressed in arthritis. Neovascularization is one of the pathological characteristics of arthritis. However, the role of IL-1β in the angiogenesis of chondrocytes remains unknown. In the present study, we demonstrate that stimulating chondrocytes (ATDC5) with IL-1β increased the expression of FGF (fibroblast growth factor)-2, a potent angiogenic inducer, and then promoted EPC (endothelial progenitor cell) tube formation and migration. In addition, FGF-2-neutralizing antibody abolished ATDC5-conditional medium-mediated angiogenesis in vitro, as well as its angiogenic effects in the CAM (chick chorioallantoic membrane) assay and Matrigel plug nude mice model in vivo. IHC (immunohistochemistry) staining from a CIA (collagen-induced arthritis) mouse model also demonstrates that arthritis increased the expression of IL-1β and FGF-2, as well as EPC homing in articular cartilage. Moreover, IL-1β-induced FGF-2 expression via IL-1RI (type-1 IL-1 receptor), ROS (reactive oxygen species) generation, AMPK (AMP-activated protein kinase), p38 and NF-κB (nuclear factor κB) pathway has been demonstrated. On the basis of these findings, we conclude that IL-1β promotes FGF-2 expression in chondrocytes through the ROS/AMPK/p38/NF-κB signalling pathway and subsequently increases EPC angiogenesis. Therefore IL-1β serves as a link between inflammation and angiogenesis during arthritis.

Characterisation of lubricin in synovial fluid from horses with osteoarthritis

REASON FOR PERFORMING STUDY

The glycoprotein lubricin contributes to the boundary lubrication of the articular cartilage surface. The early events of osteoarthritis involve the superficial layer where lubricin is synthesised.

OBJECTIVES

To characterise the glycosylation profile of lubricin in synovial fluid from horses with osteoarthritis and study secretion and degradation of lubricin in an in vitro inflammation cartilage model.

STUDY DESIGN

In vitro study.

METHODS

Synovial fluid samples collected from horses with joints with normal articular cartilage and structural osteoarthritic lesions; with and without osteochondral fragments, were analysed for the lubricin glycosylation profiles. Articular cartilage explants were stimulated with or without interleukin-1β for 25 days. Media samples collected at 3-day intervals were analysed by quantitative proteomics, western blot and enzyme-linked immunosorbent assay.

RESULTS

O-glycosylation profiles in synovial fluid revealed both Core 1 and 2 O-glycans, with Core 1 O-glycans predominating. Synovial fluid from normal joints (49.5 ± 1.9%) contained significantly lower amounts of monosialylated Core 1 O-glycans compared with joints with osteoarthritis (53.8 ± 7.8%, P = 0.03) or joints with osteochondral fragments (57.3 ± 8.8%, P = 0.001). Additionally, synovial fluid from normal joints (26.7 ± 6.7%) showed higher amounts of disialylated Core 1 O-glycan than from joints with osteochondral fragments (21.2 ± 4.9%, P = 0.03). A C-terminal proteolytic cleavage site in lubricin was found in synovial fluid from normal and osteochondral fragment joints and in media from interleukin-1β stimulated and unstimulated articular cartilage explants.

CONCLUSIONS

This is the first demonstration of a change in the glycosylation profile of lubricin in synovial fluid from diseased equine joints compared with that from normal joints. We demonstrate an identical proteolytic cleavage site of lubricin both in vitro and in vivo. The reduced sialation of lubricin in synovial fluid from diseased joints may affect the boundary lubricating ability of the superficial layer of articular cartilage and could be one of the early events in the progression of osteoarthritis.

Investigational drugs for the treatment of osteoarthritis

INTRODUCTION

Osteoarthritis (OA) is a common joint disease with multiple pathophysiological processes, affecting the whole joint. Current therapeutic options such as NSAIDs can provide a palliative effect on symptoms but have limited effect on disease progression. New drugs targeting OA structures may retard disease progression at an earlier stage and delay the need for joint replacement.

AREAS COVERED

Some drugs have entered into clinical trials and a few, such as strontium ranelate, do have improvements in both pain and structure changes. However, most of them have failed in clinical trials largely due to increased side effects or the failure to identify the right OA phenotype for the right drug in clinical design. This review describes various investigational drugs developed for the treatment of OA covering those at stages from preclinical experiments to early phase clinical trials. They include drugs for slowing cartilage degradation, regulating cartilage metabolism, targeting subchondral bone, controlling inflammation and relieving pain.

EXPERT OPINION

Treatment options for OA remain limited. However, with the emergence of sensitive tools to detect early disease progression and identification of different OA phenotypes, disease-modifying anti-OA drugs with increased benefit and reduced risks will become available for OA treatment in the near future.

A Novel Synthesized Sulfonamido-Based Gallate-JEZ-C as Potential Therapeutic Agents for Osteoarthritis

Gallic acid (GA) and its derivatives are anti-inflammatory agents reported to have an effect on osteoarthritis (OA). However, GA has much weaker anti-oxidant effects and inferior bioactivity compared with its derivatives. We modified GA with the introduction of sulfonamide to synthesize a novel compound named JEZ-C and analyzed its anti-arthritis and chondro-protective effects. Comparison of JEZ-C with its sources i.e. GA and Sulfamethoxazole (SMZ) was also performed. Results showed that JEZ-C could effectively inhibit the IL-1-mediated induction of MMP-1 and MMP-13 and could induce the expression of TIMP-1, which demonstrated its ability to reduce the progression of OA. JEZ-C can also exert chondro-protective effects by promoting cell proliferation and maintaining the phenotype of articular chondrocytes, as evidenced by improved cell growth, enhanced synthesis of cartilage specific markers such as aggrecan, collagen II and Sox9. Meanwhile, expression of the collagen I gene was effectively downregulated, revealing the inhibition of chondrocytes dedifferentiation by JEZ-C. Hypertrophy that may lead to chondrocyte ossification was also undetectable in JEZ-C groups. The recommended dose of JEZ-C ranges from 6.25×10^-7 μg/ml to 6.25×10^-5 μg/ml, among which the most profound response was observed with 6.25×10^-6 μg/ml. In contrast, its source products of GA and SMZ have a weak effect not only in the inhibition of OA but also in the bioactivity of chondrocytes, which indicated the significance of this modification. This study revealed JEZ-C as a promising novel agent in the treatment of chondral and osteochondral lesions.

An overview of a novel, water-soluble undenatured type II collagen (NEXT-II)

BACKGROUND

Osteoarthritis, the most common form of arthritis, is a crippling, chronic debilitating bone disease that commonly affects humans, dogs, and horses. Inflammation and inflammatory responses are key factors for causing swelling, redness, pain, and loss of movement in arthritic animals and humans.

METHODS AND RESULTS

We developed a novel, water-soluble, undenatured type II collagen (NEXT-II) for osteoarthritis. NEXT-II demonstrated broad-spectrum safety and nonmutagenicity. NEXT-II exhibited significant efficacy in ameliorating pain and inflammation in collagen-induced arthritis in mice. NEXT-II enhanced the proportion of CD4+CD25+T cells, and gene expressions of stimulated dendritic cells induced markers for regulatory T cell such as forkhead box p3, transforming growth factor-β1, and CD25. Furthermore, NEXT-II was assessed in moderately arthritic dogs receiving either placebo or 10 mg NEXT-II over a period of 150 days. NEXT-II exhibited a significant reduction in overall pain, pain after limb manipulation, and pain after physical exertion compared to the control dogs. Physical health and serum chemistry (alanine aminotransferase, blood urea nitrogen, and creatine kinase) were not altered when these arthritic dogs were treated over a period of 150 days.

CONCLUSIONS

These results demonstrate the broad-spectrum safety and efficacy of NEXT-II in ameliorating the symptoms of arthritis. Key Teaching Points: •A novel, water-soluble, undenatured type II collagen (NEXT-II) was developed for osteoarthritis. •The safety studies including acute oral and dermal toxicity, primary dermal and primary eye irritation, Ames' bacterial reverse mutation assay, mouse lymphoma assay, and 150-day long-term safety studies were conducted. •NEXT-II exhibited significant efficacy in ameliorating pain and inflammation in collagen-induced arthritis in mice. •NEXT-II exhibited a significant reduction in overall pain in moderately arthritic dogs without changing physical parameters.

Pain reduction with oral methotrexate in knee osteoarthritis, a pragmatic phase iii trial of treatment effectiveness (PROMOTE): study protocol for a randomized controlled trial

Background

Osteoarthritis (OA) is the fastest growing cause of disability worldwide. Current treatments for OA are severely limited and a large proportion of people with OA live in constant, debilitating pain. There is therefore an urgent need for novel treatments to reduce pain. Synovitis is highly prevalent in OA and is associated with pain. In inflammatory arthritides such as rheumatoid arthritis, methotrexate (MTX) is the gold standard treatment for synovitis and has a well-known, acceptable toxicity profile. We propose that using MTX to treat patients with symptomatic knee OA will be a practical and safe treatment to reduce synovitis and, consequently, pain.

Methods/Design

Pain Reduction with Oral Methotrexate in knee Osteoarthritis, a pragmatic phase III trial of Treatment Effectiveness (PROMOTE) is an investigator-initiated, multi-centre, randomized, double-blind, pragmatic placebo-controlled trial. A total of 160 participants with symptomatic knee OA will be recruited across primary and secondary care sites in the United Kingdom and randomized on a 1:1 basis to active treatment or placebo, in addition to usual care, for 12 months. As is usual practice for MTX, dosing will be escalated over six weeks to 25 mg (or maximum tolerated dose) weekly for the remainder of the study. The primary endpoint is change in average knee pain during the past week (measured on an 11-point numerical rating scale) between baseline and six months. Secondary endpoints include other self-reported pain, function and quality-of-life measures. A health economics analysis will also be performed. A magnetic resonance imaging substudy will be conducted to provide an explanatory mechanism for associated symptom change by examining whether MTX reduces synovitis and whether this is related to symptom change. Linear and logistic regression will be used to compare changes between groups using univariable and multivariable modelling analyses. All analyses will be conducted on an intention-to-treat basis.

Discussion

The PROMOTE trial is designed to examine whether MTX is an effective analgesic treatment for OA. The MRI substudy will address the relationship between synovitis and symptom change. This will potentially provide a much needed new treatment for knee OA.

Trial registration

Current Controlled Trials identifier: ISRCTN77854383 (registered: 25 October 2013).

Autologous protein solution prepared from the blood of osteoarthritic patients contains an enhanced profile of anti-inflammatory cytokines and anabolic growth factors

The objective of this clinical study was to test if blood from osteoarthritis (OA) patients (n = 105) could be processed by a device system to form an autologous protein solution (APS) with preferentially increased concentrations of anti-inflammatory cytokines compared to inflammatory cytokines. To address this objective, APS was prepared from patients exhibiting radiographic evidence of knee OA. Patient metrics were collected including: demographic information, medical history, medication records, and Knee Injury and Osteoarthritis Outcome Score (KOOS) surveys. Cytokine and growth factor concentrations in whole blood and APS were measured using enzyme-linked immunosorbent assays. Statistical analyses were used to identify relationships between OA patient metrics and cytokines. The results of this study indicated that anti-inflammatory cytokines were preferentially increased compared to inflammatory cytokines in APS from 98% of OA patients. APS contained high concentrations of anti-inflammatory proteins including 39,000 ± 20,000 pg/ml IL-1ra, 21,000 ± 5,000 pg/ml sIL-1RII, 2,100 ± 570 pg/ml sTNF-RI, and 4,200 ± 1,500 pg/ml sTNF-RII. Analysis of the 82 patient metrics indicated that no single patient metric was strongly correlated (R(2)  > 0.7) with the key cytokine concentrations in APS. Therefore, APS can be prepared from a broad range of OA patients.

The future of osteoarthritis therapeutics: emerging biological therapy

Biological therapy is a thriving area of research and development, and is well established for chronic forms of rheumatoid arthritis (RA) and ankylosing spondylitis (AS). However, there is no clinically validated biological therapy for osteoarthritis (OA). Chronic forms of OA are increasingly viewed as an inflammatory disease. OA was largely regarded as a “wear and tear disease”. However, the disease is now believed to involve “low grade” inflammation and the growth of blood vessels and nerves from the subchondral bone into articular cartilage. This realization has focused research effort on the development and evaluation of biological therapy that targets proinflammatory mediators, angiogenic factors and cytokines in articular cartilage, subchondral bone and synovium in chronic forms of OA. This review article provides an overview of emerging biological therapy for OA, and discusses recent molecular targets implicated in angiogenesis and neurogenesis and progress with antibody-based therapy, calcitonin, and kartogenin, the small molecule stimulator of chondrogenesis.

Biology of platelet-rich plasma and its clinical application in cartilage repair

Platelet-rich plasma (PRP) is an autologous concentrated cocktail of growth factors and inflammatory mediators, and has been considered to be potentially effective for cartilage repair. In addition, the fibrinogen in PRP may be activated to form a fibrin matrix to fill cartilage lesions, fulfilling the initial requirements of physiological wound healing. The anabolic, anti-inflammatory and scaffolding effects of PRP based on laboratory investigations, animal studies, and clinical trials are reviewed here. In vitro, PRP is found to stimulate cell proliferation and cartilaginous matrix production by chondrocytes and adult mesenchymal stem cells (MSCs), enhance matrix secretion by synoviocytes, mitigate IL-1β-induced inflammation, and provide a favorable substrate for MSCs. In preclinical studies, PRP has been used either as a gel to fill cartilage defects with variable results, or to slow the progression of arthritis in animal models with positive outcomes. Findings from current clinical trials suggest that PRP may have the potential to fill cartilage defects to enhance cartilage repair, attenuate symptoms of osteoarthritis and improve joint function, with an acceptable safety profile. Although current evidence appears to favor PRP over hyaluronan for the treatment of osteoarthritis, the efficacy of PRP therapy remains unpredictable owing to the highly heterogeneous nature of reported studies and the variable composition of the PRP preparations. Future studies are critical to elucidate the functional activity of individual PRP components in modulating specific pathogenic mechanisms.

Autologous solution protects bovine cartilage explants from IL-1α- and TNFα-induced cartilage degradation

Osteoarthritis (OA) is characterized by deterioration of articular cartilage driven by an imbalance of pro- and anti-inflammatory cytokines. To address the cartilage deterioration observed in OA, an autologous protein solution (APS) has been developed which has been shown to inhibit the production of destructive proteases and inflammatory cytokines from chondrocytes and monocytes, respectively. The purpose of this study was to determine the chondroprotective effect of APS on IL-1α- or TNFα-challenged bovine articular cartilage explants. Cartilage explants were cultured in the presence or absence of recombinant inflammatory cytokines, IL-1α and TNFα. Explants under equivalent inflammatory conditions were pretreated with recombinant antagonists IL-1ra, sTNF-RI, or APS to measure their inhibition of matrix degradation. Explants were further evaluated with Safranin-O, Masson's Trichrome, and Hematoxylin and Eosin histological staining. APS was more effective than recombinant antagonists in preventing cartilage matrix degradation and inhibited any measurable IL-1α-induced collagen release over a 21-day culture period. APS treatment reduced the degree of Safranin-O staining loss when cartilage explants were cultured with IL-1α or TNFα. Micrographs of APS treated cartilage explants showed an increase in observed cellularity and apparent cell division. APS may have the potential to prevent cartilage loss associated with early OA.

New horizons in osteoarthritis

Osteoarthritis (OA) is the most common type of arthritis worldwide and rapidly increasing with ageing populations. It is a major source of pain and disability for individuals and economic burden for health economies. Modern imaging, in particular magnetic resonance imaging (MRI), has helped us to understand that OA is a dynamic remodelling process involving all the structures within the joint. Inflammation is common in OA, with a high prevalence of synovitis seen on imaging, and this has been associated with joint pain. MRI detected changes within the subchondral bone are also common and associated with pain and structural progression. Targeting individual pathologies may offer potential new therapeutic options for OA; this is particularly important given the current treatments are often limited by side effects or lack of efficacy. New approaches to understanding the pathology and pain pathways in OA offer hope of novel analgesic options, for example, monoclonal antibodies against nerve growth factor and centrally acting drugs such as duloxetine, tapentadol and bradykinin receptor antagonists have all recently undergone trials in OA. While treatment for OA has until now relied on symptom management, for the first time, recent trials suggest that structure modification may be possible by treating the subchondral bone.

Potential directions for drug development for osteoarthritis

BACKGROUND

Osteoarthritis (OA) is a frustrating disease for both patient and physician because neither cause nor cure is known and there are currently no disease-modifying drugs.

OBJECTIVE

To review current therapeutic approaches as well as new findings regarding OA pathoetiology that could form the basis of future direction for the development of drugs to prevent or slow down disease progression.

METHODS

After reviewing disease progression in human OA, as demonstrated by histological analyses, the reasons for cartilage erosion are explored and possible therapeutic approaches are highlighted.

RESULTS/CONCLUSIONS

OA may be an epigenetic disease. This new concept can explain many aspects of the disease and provide reasons why therapeutic approaches until now have met with little success.

Genetic polymorphisms associated with intervertebral disc degeneration

BACKGROUND CONTEXT

Disc degeneration (DD) is a multifaceted chronic process that alters the structure and function of the intervertebral discs and can lead to painful conditions. The pathophysiology of degeneration is not well understood, but previous studies suggest that certain genetic polymorphisms may be important contributing factors leading to an increased risk of DD.

PURPOSE

To review the genetic factors in DD with a focus on polymorphisms and their putative role in the pathophysiology of degeneration. Elucidating the genetic components that are associated with degeneration could provide insights into the mechanism of the process. Furthermore, defining these relationships and eventually using them in a clinical setting may allow an identification and early intervention for those who are at a high risk for painful DD.

STUDY DESIGN

Literature review.

METHODS

This literature review focused on the studies concerning genetic polymorphisms and their associations with DD.

RESULTS

Genetic polymorphisms in 20 genes have been analyzed in association with DD, including vitamin D receptor, growth differentiation factor 5 (GDF5), aggrecan, collagen Types I, IX, and XI, fibronectin, hyaluronan and proteoglycan link protein 1 (HAPLN1), thrombospondin, cartilage intermediate layer protein (CILP), asporin, MMP1, 2, and 3, parkinson protein 2, E3 ubiquitin protein ligase (PARK2), proteosome subunit β type 9 (PSMB9), tissue inhibitor of metalloproteinase (TIMP), cyclooxygenase-2 (COX2), and IL1α, IL1β, and IL6. Each genetic polymorphism codes for a protein that has a functional role in the pathogenesis of DD.

CONCLUSIONS

There are known associations between several genetic polymorphisms and DD. Of the 20 genes analyzed, polymorphisms in vitamin D receptor, aggrecan, Type IX collagen, asporin, MMP3, IL1, and IL6 show the most promise as functional variants. Genetic studies are crucial for understanding the mechanism of the degeneration. This genetic information could eventually be used as a predictive model for determining a patient's risk for symptomatic DD.

Osteoarthritis: histology and pathogenesis

Osteoarthritis is the most common joint disease, affecting over 60 % of the elderly population, leading to incapacity of movement. The primary form is usually oligoarticular. In case of an underlying systemic disease or local injury, the cartilage destruction is considered as secondary osteoarthritis. The pathogenesis of primary osteoarthritis suggests an intrinsic disease of cartilage in which biochemical and metabolic alterations result in its breakdown. Within the last decades, different models were established concentrating on joint structures such as bones or ligaments. Changes of the subchondral bone were found to precede cartilage damage, suggesting a primary alteration of the subchondral region. Other studies concentrated on the metabolic activity of chondrocytes in healthy cartilage of patients with osteoarthritis. The precise event that leads to these changes is still not clear. This review concentrates on the histological features in the course of the disease and provides a summary on different pathogenetic risk factors.

The role of synovitis in osteoarthritis

Osteoarthritis (OA) is the most common form of arthritis worldwide yet there is still a lack of effective treatments for this condition. Increasingly, attention has turned to the role of the synovium in OA as it is now recognized, in part from the use of modern imaging techniques, that synovitis is both common and associated with pain. This offers a target for treatment, for both symptom and potential structure modification. In this review we discuss the evidence for histological and imaging-detected synovitis and the current role of antisynovial therapies in OA.

Is monocyte chemotactic protein 1 elevated in aseptic loosening of TKA? A pilot study

BACKGROUND

Failure of TKA from aseptic loosening is a growing concern, as TKA is performed with increasing frequency. Loosening is multifactorial and may be associated with elevated inflammatory cytokines in addition to biomechanical failure.

QUESTIONS/PURPOSES

We asked whether proinflammatory cytokines and chemokines are elevated in synovial fluid from patients undergoing revision surgery as compared to those with osteoarthritis (OA) or rheumatoid arthritis (RA).

METHODS

We obtained synovial fluid samples from 20 patients: six with aseptic loosening of TKA (all with bone loss), 10 with primary OA, and four with RA. A panel of cytokines/chemokines was screened using a SearchLight(®) Array (Pierce Biotechnology, Rockford, IL, USA) in one revision sample. Using these data, we assayed the synovial fluids for monocyte chemotactic protein 1 (MCP-1) by ELISA.

RESULTS

We observed an increase in synovial MCP-1 levels in samples from patients planned for TKA revision compared to those with OA or RA. In patients undergoing revision arthroplasty, the mean (± SD) MCP-1 concentration was 21,233 ± 18,966 pg/mL (range, 1550-50,657 pg/mL; n = 6). In patients with OA, the mean MCP-1 level was 3012 ± 3321 pg/mL. In patients with RA, the mean MCP-1 concentration was 690 ± 561 pg/mL.

CONCLUSIONS

All patients undergoing revision TKA showed elevated concentrations of MCP-1 compared to patients with OA and RA, suggesting MCP-1 may serve as a potential marker or predictor of bone loss in patients undergoing revision surgery.

CLINICAL RELEVANCE

MCP-1 may be a novel biomarker in patients showing early symptoms of aseptic loosening of TKA.

The effect of vascular endothelial growth factor on aggrecan and type II collagen expression in rat articular chondrocytes

The expression of vascular endothelial growth factor (VEGF) directly correlates with the Mankin score and the degree of cartilage destruction. The biological activity of VEGF on articular cartilage remains unknown, so this study was performed to investigate the effect of VEGF on aggrecan and type II collagen expression in vitro. We carried out this study at the Center Laboratory of Renmin Hospital at Wuhan University. Rat articular chondrocytes were cultured in a monolayer. Then, the experiment was divided into 4 groups: group A (control group), without any disposal; group B, treated with 10 ng/ml VEGF; group C, treated with 10 ng/ml IL-1β; and group D, treated with 10 ng/ml VEGF + 10 ng/ml IL-1β. After 48 h, messenger RNA (mRNA) expression of aggrecan and type II collagen was evaluated by real-time polymerase chain reaction (real-Time PCR), and protein expression of aggrecan and type II collagen was detected by Western blotting. VEGF was found to significantly inhibit the expression of aggrecan and type II collagen at the gene and protein levels. These findings suggest that VEGF may result in degeneration of articular cartilage by inhibiting the synthesis and expression of aggrecan and type II collagen.

Autologous protein solution inhibits MMP-13 production by IL-1β and TNFα-stimulated human articular chondrocytes

Catabolic inflammatory cytokines are prevalent in osteoarthritis (OA). The purpose of this study was to evaluate an autologous protein solution (APS) as a potential chondroprotective agent for OA therapy. APS was prepared from platelet-rich plasma (PRP). The APS solution contained both anabolic (bFGF, TGF-β1, TGF-β2, EGF, IGF-1, PDGF-AB, PDGF-BB, and VEGF) and anti-inflammatory (IL-1ra, sTNF-RI, sTNF-RII, IL-4, IL-10, IL-13, and IFNγ) cytokines but low concentrations of catabolic cytokines (IL-1α, IL-1β, TNFα, IL-6, IL-8, IL-17, and IL-18). Human articular chondrocytes were pre-incubated with the antagonists IL-1ra, sTNF-RI, or APS prior to the addition of recombinant human IL-1β or TNFα. Following exposure to inflammatory cytokines, the levels of MMP-13 in the culture medium were evaluated by ELISA. MMP-13 production stimulated in chondrocytes by IL-1β or TNFα was reduced by rhIL-1ra and sTNF-RI to near basal levels. APS was also capable of inhibiting the production of MMP-13 induced by both IL-1β and TNFα. The combination of anabolic and anti-inflammatory cytokines in the APS created from PRP may render this formulation to be a potential candidate for the treatment of inflammation in patients at early stages of OA.