Magnetic Capture of a Molecular Biomarker from Synovial Fluid in a Rat Model of Knee Osteoarthritis

Phytomolecule Epimedin C Mitigates Cartilage Extracellular Matrix Degradation and Osteoarthritis Progression in Rats

Osteoarthritis (OA) is a common degenerative joint disease associated with chronic inflammation. Epimedin C (EpiC), flavonoid from Epimedin, enhances the extracellular matrix (ECM) expression in human chondrocytes in vitro. This study aims to investigate the effects of EpiC on osteoarthritis progress in vivo. OA is induced in Lewis rats by medial meniscus transection and treatment with intra-articular injections of EpiC. EpiC treatment reduces joint swelling and improves hindlimb weight distribution in MMT-induced OA rats. Pathological changes in cartilage are observed and evaluated by the osteoarthritis research society international (OARSI) score and both EpiC groups have lower OARSI scores than the OA group. The EpiC groups also exhibit higher positive expressions of collagen II and aggrecan, and lower MMP13 and ADAMTS5 in the cartilage. RNA-seq suggest that EpiC may attenuate MMT-induced ECM degradation by inhibiting the JAK-STAT pathway. EpiC promotes the gene expressions of Col2a1 and Acan, while inhibiting Mmp13 and Col10a1 in cartilage. EpiC reduces the phosphorylated STAT3 in human chondrocyte pellets stimulated with inflammatory cytokines. In conclusion, EpiC demonstrates potential as an OA therapeutic by reducing pain and ECM degradation through p-STAT3 inhibition.

High-dose vancomycin spacers provided early recovery without nephrotoxicity compared with standard-dose in MRSA-induced periprosthetic joint infection model of rats

BACKGROUND

Periprosthetic joint infections (PJIs) are commonly treated with two-stage revision surgery utilising antibiotic-loaded spacers; however, antibiotic release from spacers is limited and usually drops below effective levels a few days after placement. This study compared high-dose and standard-dose vancomycin-loaded spacers in terms of efficacy, safety, and overall treatment duration in a rat periprosthetic joint infection model.

METHODS

Thirty male Wistar albino rats (8-10 weeks old, 300-320 g) were housed individually at standard conditions. A periprosthetic infection model was established in the right knee of the rats using methicillin-resistant Staphylococcus aureus (MRSA) -contaminated Kirschner wires. Two weeks later, the infection was verified, and the Kirschner wires were removed. Rats were randomly divided into three groups (n = 10): standard-dose (SVanc) and high-dose (HVanc) vancomycin groups had 2.5 and 7.5% vancomycin in their spacers, respectively, while the control group had no spacers. All groups received intramuscular (IM) vancomycin and gentamicin for 4 weeks after spacer implantation. Microbiological counts and vancomycin levels in the blood and joint flush samples were measured, and histopathological assessments were conducted on the femur and kidneys.

RESULTS

After spacer implantation, MRSA was eliminated in the HVanc group with 4 weeks of treatment, while the SVanc group required 6 weeks of treatment (P < 0.001). Histopathological findings of the femoral medulla and cortical samples were better in the HVanc group compared with other groups (P = 0.007). Vancomycin levels in serum remained within safe limits in all groups, and kidney damage was not observed.

CONCLUSION

The use of high-dose vancomycin spacers might accelerate the transition period, which in turn reduces the duration of systemic antibiotic use and mitigates the risk of nephrotoxicity. Thus, this method may decrease the medical costs associated with PJI treatment.

Preclinical tendon and ligament models: Beyond the 3Rs (replacement, reduction, and refinement) to 5W1H (why, who, what, where, when, how)

Several tendon and ligament animal models were presented at the 2022 Orthopaedic Research Society Tendon Section Conference held at the University of Pennsylvania, May 5 to 7, 2022. A key objective of the breakout sessions at this meeting was to develop guidelines for the field, including for preclinical tendon and ligament animal models. This review summarizes the perspectives of experts for eight surgical small and large animal models of rotator cuff tear, flexor tendon transection, anterior cruciate ligament tear, and Achilles tendon injury using the framework: "Why, Who, What, Where, When, and How" (5W1H). A notable conclusion is that the perfect tendon model does not exist; there is no single gold standard animal model that represents the totality of tendon and ligament disease. Each model has advantages and disadvantages and should be carefully considered in light of the specific research question. There are also circumstances when an animal model is not the best approach. The wide variety of tendon and ligament pathologies necessitates choices between small and large animal models, different anatomic sites, and a range of factors associated with each model during the planning phase. Attendees agreed on some guiding principles including: providing clear justification for the model selected, providing animal model details at publication, encouraging sharing of protocols and expertise, improving training of research personnel, and considering greater collaboration with veterinarians. A clear path for translating from animal models to clinical practice was also considered as a critical next step for accelerating progress in the tendon and ligament field.

Intra-articular delivery of an indoleamine 2,3-dioxygenase galectin-3 fusion protein for osteoarthritis treatment in male Lewis rats

OBJECTIVE

Osteoarthritis (OA) is driven by low-grade inflammation, and controlling local inflammation may offer symptomatic relief. Here, we developed an indoleamine 2,3-dioxygenase and galectin-3 fusion protein (IDO-Gal3), where IDO increases the production of local anti-inflammatory metabolites and Gal3 binds carbohydrates to extend IDO's joint residence time. In this study, we evaluated IDO-Gal3's ability to alter OA-associated inflammation and pain-related behaviors in a rat model of established knee OA.

METHODS

Joint residence was first evaluated with an analog Gal3 fusion protein (NanoLuc™ and Gal3, NL-Gal3) that produces luminescence from furimazine. OA was induced in male Lewis rats via a medial collateral ligament and medial meniscus transection (MCLT + MMT). At 8 weeks, NL or NL-Gal3 were injected intra-articularly (n = 8 per group), and bioluminescence was tracked for 4 weeks. Next, IDO-Gal3s's ability to modulate OA pain and inflammation was assessed. Again, OA was induced via MCLT + MMT in male Lewis rats, with IDO-Gal3 or saline injected into OA-affected knees at 8 weeks post-surgery (n = 7 per group). Gait and tactile sensitivity were then assessed weekly. At 12 weeks, intra-articular levels of IL6, CCL2, and CTXII were assessed.

RESULTS

The Gal3 fusion increased joint residence in OA and contralateral knees (p < 0.0001). In OA-affected animals, both saline and IDO-Gal3 improved tactile sensitivity (p = 0.008), but IDO-Gal3 also increased walking velocities (p ≤ 0.033) and improved vertical ground reaction forces (p ≤ 0.04). Finally, IDO-Gal3 decreased intra-articular IL6 levels within the OA-affected joint (p = 0.0025).

CONCLUSION

Intra-articular IDO-Gal3 delivery provided long-term modulation of joint inflammation and pain-related behaviors in rats with established OA.

Intra-Articular Delivery of an Indoleamine 2,3-Dioxygenase Galectin-3 Fusion Protein for Osteoarthritis Treatment in Male Lewis Rats

Objective : Controlling joint inflammation can improve osteoarthritis (OA) symptoms; however, current treatments often fail to provide long-term effects. We have developed an indoleamine 2,3-dioxygenase and galectin-3 fusion protein (IDO-Gal3). IDO converts tryptophan to kynurenines, directing the local environment toward an anti-inflammatory state; Gal3 binds carbohydrates and extends IDO's joint residence time. In this study, we evaluated IDO-Gal3's ability to alter OA-associated inflammation and pain-related behaviors in a rat model of established knee OA. Methods : Joint residence was first evaluated with an analog Gal3 fusion protein (NanoLuc™ and Gal3, NL-Gal3) that produces luminescence from furimazine. OA was induced in male Lewis rats via a medial collateral ligament and medial meniscus transection (MCLT+MMT). At 8 weeks, NL or NL-Gal3 were injected intra-articularly (n=8 per group), and bioluminescence was tracked for 4 weeks. Next, IDO-Gal3's ability to modulate OA pain and inflammation was assessed. Again, OA was induced via MCLT+MMT in male Lewis rats, with IDO-Gal3 or saline injected into OA-affected knees at 8 weeks post-surgery (n=7 per group). Gait and tactile sensitivity were then assessed weekly. At 12 weeks, intra-articular levels of IL6, CCL2, and CTXII were assessed. Results : The Gal3 fusion increased joint residence in OA and contralateral knees (p<0.0001). In OA-affected animals, IDO-Gal3 improved tactile sensitivity (p=0.002), increased walking velocities (p≤0.033), and improved vertical ground reaction forces (p≤0.04). Finally, IDO-Gal3 decreased intra-articular IL6 levels within the OA-affected joint (p=0.0025). Conclusion : Intra-articular IDO-Gal3 delivery provided long-term modulation of joint inflammation and pain-related behaviors in rats with established OA.

Nanotechnology and osteoarthritis; part 1: Clinical landscape and opportunities for advanced diagnostics

Osteoarthritis (OA) is a disease of the entire joint, often triggered by cartilage injury, mediated by a cascade of inflammatory pathways involving a complex interplay among metabolic, genetic, and enzymatic factors that alter the biochemical composition, microstructure, and biomechanical performance. Clinically, OA is characterized by degradation of the articular cartilage, thickening of the subchondral bone, inflammation of the synovium, and degeneration of ligaments that in aggregate reduce joint function and diminish quality of life. OA is the most prevalent joint disease, affecting 140 million people worldwide; these numbers are only expected to increase, concomitant with societal and financial burden of care. We present a two-part review encompassing the applications of nanotechnology to the diagnosis and treatment of OA. Herein, part 1 focuses on OA treatment options and advancements in nanotechnology for the diagnosis of OA and imaging of articular cartilage, while part 2 (10.1002/jor.24842) summarizes recent advances in drug delivery, tissue scaffolds, and gene therapy for the treatment of OA. Specifically, part 1 begins with a concise review of the clinical landscape of OA, along with current diagnosis and treatments. We next review nanoparticle contrast agents for minimally invasive detection, diagnosis, and monitoring of OA via magnetic resonace imaging, computed tomography, and photoacoustic imaging techniques as well as for probes for cell tracking. We conclude by identifying opportunities for nanomedicine advances, and future prospects for imaging and diagnostics.

Use of magnetic capture to identify elevated levels of CCL2 following intra-articular injection of monoiodoacetate in rats

PURPOSE

Synovial fluid biomarkers help evaluate osteoarthritis (OA) development. Magnetic capture, our new magnetic nanoparticle-based technology, has proven to be effective for determining extracellular matrix fragment levels in two rat OA models. Here, the feasibility of magnetic capture for detecting monocyte chemoattractant protein-1 (MCP-1 or CCL2) is demonstrated after intra-articular injection of monoiodoacetate (MIA) in the rat knee.

METHODS

Forty-eight male Lewis rats received a right hind limb, intra-articular injection of MIA (1 mg in 25 µl of saline) or 25 µl of saline. Magnetic capture and lavage were performed at 7 days after injection (n = 6 per treatment per procedure), with magnetic capture additionally performed at 14 and 28 days post-injection (n = 6 per treatment per time point). CCL2 was also assessed in serum.

RESULTS

Serum CCL2 levels revealed no difference between MIA and saline animals (p = 0.0851). In contrast, magnetic capture and lavage detected a significant increase of CCL2 in the MIA-injected knee, with the MIA-injected knee having elevated CCL2 compared to contralateral and saline-injected knees (p = 0.00016 (contralateral) and p = 0.00016 (saline) for magnetic capture; p = 0.00023 (contralateral) and p = 0.00049 (saline) for lavage).

CONCLUSIONS

Magnetic capture of CCL2 was successfully developed and applied to determine levels of CCL2 in a rat knee. Magnetic capture detected a statistically significant increase of CCL2 in MIA-injected knees compared to controls, and CCL2 levels stayed relatively stable from week 1 through week 4 post-MIA injection.

Electrostatically modulated magnetophoretic transport of functionalised iron-oxide nanoparticles through hydrated networks

Factors that determine magnetophoretic transport of magnetic nanoparticles (MNPs) through hydrated polymer networks under the influence of an external magnetic field gradient were studied. Functionalised iron oxide cores (8.9 nm core diameter) were tracked in real-time as they moved through agarose gels under the influence of an inhomogeneous magnetic field. Terminal magnetophoretic velocities were observed in all cases, these were quantified and found to be highly reproducible and sensitive to the conditions. Increasing agarose content reduced magnetophoretic velocity, we attribute this to increasingly tortuous paths through the porous hydrated polymer network and propose a new factor to quantify the tortuosity. The impact of MNP surface functionalisation, charge, network fixed charge content, and ionic strength of the aqueous phase on velocity were studied to separate these effects. For MNPs functionalised with polyethylene glycol (PEG) increasing chain length reduced velocity but the tortuosity extracted, which is a function of the network, was unchanged; validating the approach. For charged citrate- and arginine-functionalised MNPs, magnetophoretic velocities were found to increase for particles with positive and decrease for particles with negative zeta potential. In both cases these effects could be moderated by reducing the number of agarose anionic residues and/or increasing the ionic strength of the aqueous phase; conditions under which tortuosity again becomes the critical factor. A model for MNP transport identifying the contributions from the tortuous pore network and from electrostatic effects associated with the pore constrictions is proposed.

Characterization of Post-Traumatic Osteoarthritis in Rats Following Anterior Cruciate Ligament Rupture by Non-Invasive Knee Injury (NIKI)

Small animal models are essential for studying anterior cruciate ligament (ACL) injury, one of the leading risk factors for post-traumatic osteoarthritis (PTOA). Non-surgical models of ACL rupture have recently surged as a new tool to study PTOA, as they circumvent the confounding effects of surgical disruption of the joint. These models primarily have been explored in mice and rabbits, but are relatively understudied in rats. The purpose of this work was to establish a non-invasive, mechanical overload model of ACL rupture in the rat and to study the disease pathogenesis following the injury. ACL rupture was induced via non-invasive tibial compression in Lewis rats. Disease state was characterized for 4 months after ACL rupture via histology, computed tomography, and biomarker capture from the synovial fluid. The non-invasive knee injury (NIKI) model created consistent ACL ruptures without direct damage to other tissues and resulted in conventional OA pathology. NIKI knees exhibited structural changes as early as 4 weeks post-injury, including regional structural changes to cartilage, chondrocyte and cartilage disorganization, changes to the bone architecture, synovial hyperplasia, and the increased presence of biomarkers of cartilage fragmentation and pro-inflammatory cytokines. These results suggest that this model can be a valuable tool to study PTOA. By establishing the fundamental pathogenesis of this injury, additional opportunities are created to evaluate unique contributing factors and potential therapeutic interventions for this disease. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:356-367, 2020.

The effects of age on the severity of joint damage and intra-articular inflammation following a simulated medial meniscus injury in 3, 6, and 9 month old male rats

Purpose: Aging is a known risk factor for osteoarthritis (OA). Several transgenic rodent models have been used to investigate the effects of accelerated or delayed aging in articular joints. However, age-effects on the progression of post-traumatic OA are less frequently evaluated. The objective of this study is to evaluate how animal age affects the severity of intra-articular inflammation and joint damage in the rat medial collateral ligament plus medial meniscus transection (MCLT+MMT) model of knee OA.Methods: Forty-eight, male Lewis rats were aged to 3, 6, or 9 months old. At each age, eight rats received either an MCLT+MMT surgery or a skin-incision. At 2 months post-surgery, intra-articular evidence of CTXII, IL1β, IL6, TNFα, and IFNγ was evaluated using a multiplex magnetic capture technique, and histological evidence of OA was assessed via a quantitative histological scoring technique.Results: Elevated levels of CTXII and IL6 were found in MCLT+MMT knees relative to skin-incision and contralateral controls; however, animal age did not affect the severity of joint inflammation. Conversely, histological investigation of cartilage damage showed larger cartilage lesion areas, greater width of affected cartilage, and more evidence of hypertrophic cartilage damage in MCLT+MMT knees with age.Conclusions: These data indicate the severity of cartilage damage subsequent to MCLT+MMT surgery is related to the rat's age at the time of injury. However, despite greater levels of cartilage damage, the level of intra-articular inflammation was not necessarily affected in 3, 6, and 9 month old male rats.

Bioluminescence and second harmonic generation imaging reveal dynamic changes in the inflammatory and collagen landscape in early osteoarthritis

Osteoarthritis (OA) is a leading cause of chronic disability whose mechanism of pathogenesis is largely elusive. Local inflammation is thought to play a key role in OA progression, especially in injury-associated OA. While multiple inflammatory cytokines are detected, the timing and extent of overall inflammatory activities in early OA and the manner by which joint inflammation correlates with cartilage structural damage are still unclear. We induced OA via destabilization of the medial meniscus (DMM) in NFκB luciferase reporter mice, whose bioluminescent signal reflects the activity of NFκB, a central mediator of inflammation. Bioluminescence imaging data showed that DMM and sham control joints had a similar surge of inflammation at 1-week post-surgery, but the DMM joint exhibited a delay in resolution of inflammation in subsequent weeks. A similar trend was observed with synovitis, which we found to be mainly driven by synovial cell density and inflammatory infiltration rather than synovial lining thickness. Interestingly, an association between synovitis and collagen structural damage was observed in early OA. Using Second Harmonic Generation (SHG) imaging, we analyzed collagen fiber organization in articular cartilage. Zonal differences in collagen fiber thickness and organization were observed as soon as OA initiated after DMM surgery, and persisted over time. Even at 1-week post-surgery, the DMM joint showed a decrease in collagen fiber thickness in the deep zone and an increase in collagen fiber disorganization in the superficial zone. Since we were able detect and quantify collagen structural changes very early in OA development by SHG imaging, we concluded that SHG imaging is a highly sensitive tool to evaluate pathological changes in OA. In summary, this study uncovered a dynamic profile of inflammation and joint cartilage damage during OA initiation and development, providing novel insights into OA pathology.

Comparing intra-articular CTXII levels assessed via magnetic capture or lavage in a rat knee osteoarthritis model

OBJECTIVE

Parallel measures of osteoarthritis (OA) across species can help evaluate OA models relative to humans. Toward this need, our group recently developed a magnetic nanoparticle-based technology, termed magnetic capture, to analyze biomarkers within a rat knee. The objectives of this study were to directly compare magnetic capture to lavage, and assess c-telopeptide of collagen type II (CTXII) in the rat medial meniscus transection (MMT) model of knee OA.

DESIGN

MMT surgery was performed in 30 male Lewis rats (3 months, 250 g). Using lavage or magnetic capture, CTXII was assessed in the OA-affected and contralateral knee at 1 week (n = 6 per group) or 4 weeks (n = 8 per group) after surgery.

RESULTS

While lavage detected elevated CTXII concentrations in the OA-affected knee at 1 week (P = 0.002), magnetic capture detected elevated CTXII levels in the OA-affected knee at 4 weeks (P = 0.016). While magnetic capture did not detect significant elevation of CTXII at week 1, five of six rats evaluated with magnetic capture had higher CTXII levels in the OA-affected joint relative to the contralateral limb. Moreover, with magnetic capture, CTXII levels increased from 1 week to 4 weeks, corresponding to histological damage. CTXII concentrations evaluated via lavage were relatively constant across time.

CONCLUSIONS

Magnetic capture and lavage evaluate CTXII in different ways: Magnetic capture measures total CTXII in the joint, while lavage measures concentration. Our data indicate magnetic capture may be advantageous at later time points, where CTXII can be diluted by effusions.

Osteoarthritis Year in Review 2016: biomarkers (biochemical markers)

PURPOSE

The aim of this "Year in Review" article is to summarize and discuss the implications of biochemical marker related articles published between the Osteoarthritis Research Society International (OARSI) 2015 Congress in Seattle and the OARSI 2016 Congress in Amsterdam.

METHODS

The PubMed/MEDLINE bibliographic database was searched using the combined keywords: 'biomarker' and 'osteoarthritis'. The PubMed/MEDLINE literature search was conducted using the Advanced Search Builder function (http://www.ncbi.nlm.nih.gov/pubmed/advanced).

RESULTS

Over two hundred new biomarker-related papers were published during the literature search period. Some papers identified new biomarkers whereas others explored the biological properties and clinical utility of existing markers. There were specific references to several adipocytokines including leptin and adiponectin. ADAM Metallopeptidase with Thrombospondin Type 1 motif 4 (ADAMTS-4) and aggrecan ARGS neo-epitope fragment (ARGS) in synovial fluid (SF) and plasma chemokine (CeC motif) ligand 3 (CCL3) were reported as potential new knee biomarkers. New and refined proteomic technologies and novel assays including a fluoro-microbead guiding chip (FMGC) for measuring C-telopeptide of type II collagen (CTX-II) in serum and urine and a novel magnetic nanoparticle-based technology (termed magnetic capture) for collecting and concentrating CTX-II, were described this past year.

CONCLUSION

There has been steady progress in osteoarthritis (OA) biomarker research in 2016. Several novel biomarkers were identified and new technologies have been developed for measuring existing biomarkers. However, there has been no "quantum leap" this past year and identification of novel early OA biomarkers remains challenging. During the past year, OARSI published a set of recommendations for the use of soluble biomarkers in clinical trials, which is a major step forward in the clinical use of OA biomarkers and bodes well for future OA biomarker development.