Intra-articular injection of hyaluronan restores the aberrant expression of matrix metalloproteinase-13 in osteoarthritic subchondral bone

HYBID in osteoarthritis: Potential target for disease progression

HYBID is a new hyaluronan-degrading enzyme and exists in various cells of the human body. Recently, HYBID was found to over-express in the osteoarthritic chondrocytes and fibroblast-like synoviocytes. According to these researches, high level of HYBID is significantly correlated with cartilage degeneration in joints and hyaluronic acid degradation in synovial fluid. In addition, HYBID can affect inflammatory cytokine secretion, cartilage and synovium fibrosis, synovial hyperplasia via multiple signaling pathways, thereby exacerbating osteoarthritis. Based on the existing research of HYBID in osteoarthritis, HYBID can break the metabolic balance of HA in joints through the degradation ability independent of HYALs/CD44 system and furthermore affect cartilage structure and mechanotransduction of chondrocytes. In particular, in addition to HYBID itself being able to trigger some signaling pathways, we believe that low-molecular-weight hyaluronan produced by excess degradation can also stimulate some disease-promoting signaling pathways by replacing high-molecular-weight hyaluronan in joints. The specific role of HYBID in osteoarthritis is gradually revealed, and the discovery of HYBID raises the new way to treat osteoarthritis. In this review, the expression and basic functions of HYBID in joints were summarized, and reveal potential role of HYBID as a key target in treatment for osteoarthritis.

Efficacy of single high-molecular-weight versus triple low-molecular-weight hyaluronic acid intra-articular injection among knee osteoarthritis patients

Background

To compare intra-articular (IA) knee injections of a cross-linked high-molecular-weight hyaluronic acid (HMW-HA) with a linear low-molecular weight HA (LMW-HA) in terms of pain and functional improvement among knee osteoarthritis (OA) patients.

Methods

In this single-blinded RCT, the patients were randomly divided into two groups for HA injections. The first group received an HMW-HA (Arthromac) injection, while the other received three weekly LMW-HA (Hyalgan) injections. Pain and function were assessed using the outcome measures including WOMAC, Lequesne and VAS indices, once prior to injection, as well as 2 and 6 months after injections.

Results

A total of 90 patients were included. There was no significant difference in baseline characteristics including age and sex between the two groups. Our analysis showed that total WOMAC, Lequesne and VAS mean scores remarkably improved at both follow-up time-points compared to the baseline measurements (p < 0.001). There was no significant superiority between the two therapeutic protocols according to our outcome measures at any time-point of follow-up. The only except was about the improvement in WOMAC stiffness subscale that was significantly higher in LMW-HA group compared to HMW-HA (p = 0.021). Moreover, no significant difference was observed in minor complications and injection-induced pain scores between the two groups.

Conclusion

This study proved that a single HMW-HA injection is as effective as multiple injections of LMW-HA counterparts in periods of 2 and 6 months follow-up.

This study protocol was registered in Iranian database of RCTs (IRCT; www.irct.ir) with the trial registration number IRCT20130523013442N24 and registration date 2018-07-13.

Inhibition of CD44 induces apoptosis, inflammation, and matrix metalloproteinase expression in tendinopathy

Apoptosis has emerged as a primary cause of tendinopathy. CD44 signaling pathways exert anti-apoptotic and -inflammatory effects on tumor cells, chondrocytes, and fibroblast-like synoviocytes. The aim of this study was to examine the association among CD44, apoptosis, and inflammation in tendinopathy. Expression of CD44 and apoptotic cell numbers in tendon tissue from patients with long head of biceps (LHB) tendinopathy were determined according to the histological grades of tendinopathy. Primary tenocytes from Achilles tendon of Sprague-Dawley rats 1 week after collagenase injection were cultured with an antagonizing antibody against CD44. Treatment responses were determined by evaluating cell viability and expression of tendon-related proliferation markers, inflammatory mediators, and apoptosis. The expression of CD44 and apoptosis were positively correlated with the severity of tendinopathy in the human LHB tendinopathy. Furthermore, CD44 expression and apoptotic cells were co-stained in tendinopathic tendon. Blocking the CD44 signaling pathways in rat primary tenocytes by OX-50 induced cell apoptosis and the elevated levels of cleaved caspase-3. Furthermore, they had decreased cell viability and expression of collagen type I, type III, tenomodulin, and phosphorylated AKT. In contrast, there were elevated levels of inflammatory mediators, including interleukin (IL)-1β, IL-6, tumor necrosis factor-α, cyclooxygenase-2, and phosphorylated NF-κB, as well as matrix metalloproteinase (MMP) family members including MMP-1, -3, -9, and -13 in tenocytes upon OX-50 treatment. This study is the first to demonstrate the association of CD44 and apoptosis in tendinopathy. Our data imply that CD44 may play a role in tendinopathy via regulating apoptosis, inflammation, and extracellular matrix homeostasis.

Intermediate Molecular Mass Hyaluronan and CD44 Receptor Interactions Enhance Neutrophil Phagocytosis and IL-8 Production via p38- and ERK1/2-MAPK Signalling Pathways

CD44 is a common leukocyte adhesion molecule expressed on the surface of various cells. Hyaluronan (HA), the natural ligand of CD44, is a simple repeated disaccharide with variable molecular mass that is widely distributed on cell surfaces and the connective tissue matrix. The binding of small molecular mass HA (SMM-HA, MW < 80 kDa) to CD44 on immune-related cells elicits cell proliferation, differentiation, and cytokine production. However, the effects and molecular basis of intermediate molecular mass HA (IMM-HA, MW ≈ 500 kDa)-CD44 interactions on polymorphonuclear neutrophil (PMN) functions have not been elucidated. We hypothesised that IMM-HA would potentiate immune functions as well as SMM-HA. In the present study, we demonstrated IMM-HA and CD44 interactions enhanced normal PMN phagocytosis and IL-8 production compared to those with LPS or anti-CD45 treatment via F-actin cytoskeleton polymerization and subsequent ERK1/2- and p38-MAPK phosphorylation. Antibody-based inhibition of CD44 did not affect PMN function; however, F-actin aggregation was induced without MAPK phosphorylation. Enhanced PMN function via IMM-HA was determined to be CD44-dependent since this effect was abolished in DMSO-induced CD44(-) PMN-like cells obtained from HL-60 cells. In conclusion, we demonstrated that IMM-HA and CD44 interactions on PMNs potently elicit F-actin cytoskeleton polymerization and p38- and ERK1/2-MAPK phosphorylation to enhance PMN function.

Initial effects of inflammation-related cytokines and signaling pathways on the pathogenesis of post-traumatic osteoarthritis

The main pathological change in post-traumatic osteoarthritis (PTOA) is cartilage degeneration, which is closely related to inflammation and oxidative stress. Inflammation can cause degeneration of articular cartilage. Cartilage degeneration can also stimulate the progression of inflammation. It has been found that inflammatory cytokines can participate in the pathological process of cartilage degeneration through multiple signaling pathways, mainly mitogen-activated protein kinase, nuclear transcription factor kappa B, and Wnt–β-catenin signal transduction pathways. This review aimed at exploring the relationship between PTOA and inflammation-related cytokines by introducing the role of proinflammatory cytokines in chondrocyte destruction and extracellular matrix degradation.

Self-assembled thermoresponsive nanostructures of hyaluronic acid conjugates for osteoarthritis therapy

Under pathological conditions, joints and skin are often affected by an imbalance in the breakdown and production of hyaluronic acid (HA). The unique biochemical and biomechanical properties provided by HA must be restored for the long-term lubrication and cushioning effects. To overcome the inconvenience of repeated injections and the rapid degradation of exogenous HA treatments, HA is conjugated to a thermosensitive polymer, enabling the spontaneous formation of nanoparticles (HA Nano) at body temperature. Three HA Nano preparations are tested for their injectability, sensitivity to enzymatic degradation and cytocompatibility. One of them is delivered via subcutaneous and intra-articular injections to healthy mice and tested in a murine osteoarthritis (OA) model. It is found to be biocompatible, to offer a prolonged residence time at the injection site, have the ability to protect cartilage, to reduce pro-inflammatory cytokines and to preserve epiphysis thickness. In this study, HA Nano spontaneously forms nanoparticles at body temperature in vivo and is a promising candidate for the next generation of the sustainable/long-lasting treatment of OA and potentially also dermatological conditions.

Hyaluronan in experimental injured/inflamed cartilage: In vivo studies

Joint disease is characterized by an imbalance between the synthesis and degradation of articular cartilage and subchondral bone accompanied by capsular fibrosis, osteophyte formation and varying degrees of inflammation of the synovial membrane. Many animal models have been developed to study arthritis and osteoarthritis that enable experimental conditions, diet and environmental risk factors to be carefully controlled. Animal-based studies have demonstrated the positive effects of exogenous HA on the preservation of joint cartilage in different models of arthritis and osteoarthritis. Although many promising effects of exogenous HA have been reported, there remains uncertainty as to its effectiveness in reversing cartilage injury and other manifestations of joint diseases because of difficulties in interpreting and unifying the results of these studies. A review of the literature of the last decade was conducted to report the results and to determine what we have learned from animal models in relation to joint inflammation induced by experimental models and HA treatment.

Review of the Mechanism of Action for Supartz FX in Knee Osteoarthritis

Objective Summarize the biologic effects of Supartz FX for knee osteoarthritis (OA), the first worldwide clinically approved intra-articular (IA) hyaluronic acid (HA) product. Design To determine the mechanism of action from preclinical and clinical studies, a literature search was conducted of Supartz FX using academic databases from 1987 to 2016. Articles on Supartz FX that deal with its mechanisms of action were extracted, categorized, and reviewed. Results Supartz FX has 2 potential mechanisms of action: (1) biomechanical: IA Supartz FX directly improves the viscoelasticity and lubrication of synovial fluid; (2) physiologic: IA Supartz FX penetrates synovium and cartilage tissues to reach HA receptors on the surface of synoviocytes and chondrocytes. In synovium, suppression of gene expression in inflammatory mediators results in improved endogenous HA production, improved properties of synovial fluid, and reduction in pain. In cartilage, suppression of gene expression of collagenases and aggrecanases suppresses cartilage degeneration. Conclusion The net results of basic and clinical studies is that IA Supartz FX provides a more favorable biomechanical and functional environment in the knee joint. Hence, it is not only a lubricant but is also physiologically active. These actions may help explain both short- and long-term improvement in pain and function often achieved from IA Supartz FX in knee OA.

Chitosan in viscosupplementation: in vivo effect on rabbit subchondral bone

Background

To investigate the effect of intra-articular injection of Chitosan (Cs) added to hyaluronic acid (HA) on subchondral bone during osteoarthritis (OA), microarchitectural parameters and mineral density were measured in a rabbit model of early OA. A novel hybrid hydrogel adding reacetylated Cs of fungal origin to HA was compared to high molecular weight HA commercial formulation.

Method

Eighteen rabbits underwent unilateral anterior cruciate ligament transection (ACLT) and were divided into three groups (Saline-group, HA-group and Hybrid-group) depending on the intra-articular injection compound. Eight contralateral knees were used as non-operated controls (Contralateral-group). Micro-computed tomography was performed six weeks post-ACLT to study subchondral bone microarchitectural parameters and mineral density at an early stage of OA development.

Results

Cartilage thickness mean value was reduced only in Saline-group compared to Contralateral-group. When the Hybrid-group was compared to Saline-group, subchondral bone microarchitectural parameters (trabecular thickness and trabecular bone volume fraction) were significantly changed; subchondral bone plate and trabecular bone mineral densities (bone mineral density and tissue mineral density) were reduced. When the Hybrid-group was compared to HA-group, subchondral bone microarchitectural parameters (subchondral plate thickness and trabecular thickness) and trabecular bone mineral densities (bone mineral density and tissue mineral density) were significantly decreased.

Conclusion

Conclusion: Compared to HA alone, the novel hybrid hydrogel, constituted of Cs added to HA, enhanced microarchitectural parameters and mineral density changes, leading to subchondral bone loss in a rabbit model of early experimental OA.

The Disease-Modifying Effects of Hyaluronan in the Osteoarthritic Disease State

Hyaluronic acid (HA) has been a treatment modality for patients with knee osteoarthritis (OA) for many years now. Since HA was first introduced for the treatment of painful knee OA, much has been elucidated regarding both the etiology of this disease and the mechanisms by which HA may mitigate joint pain and tissue destruction. The objectives of this article are to (1) describe the etiology and pathophysiology of OA including both what is known about the genetics and biochemistry, (2) describe the role of HA on disease progression, (3) detail the antinociceptive and anti-inflammatory actions of HA in OA, and (4) present evidence of disease-modifying effects of HA in the preservation and restoration of the extracellular matrix. These data support that HA is not only just a simple device used for viscosupplementation but also a biologically active molecule that can affect the physiology of articular cartilage.

Are We Using Slow-Acting Symptomatic Chondroprotective Drugs Conscious Enough?

Background:

Osteochondral injuries constitute an entity that is widespread and can be seen in patients of all ages. Actual treatment modalities aim to relieve pain, obtain full range of movement of the joint, and improve the quality of life. There are many slow-acting chondroprotective agents prevalently used in the United States that are classified as nutritional support but not as medicines . This study presents the importance of clinical adverse effect profiles as well as the pharmacological mechanism of action and application of combinations of drugs that are widely prescribed and not subjected to control.

Methods:

Electronic databases were searched with keywords about the chondroprotective drugs without any language restriction. Evaluations of the descriptive statistics were represented via Microsoft Office Excel 2010 lists in the form of a mean±standard deviation or frequency (%). The first evaluation showed that 1502 studies were potentially relevant. Following exclusion of the 1277 studies which were not clinical, full versions of the remaining 225 studies were subjected to further evaluation. No controlled, blinded, randomized and/or comparative studies met the inclusion criteria of the study, and no studies evaluated the comparative clinical results of the hyaluronan of different molecular weights.

Results:

The findings of this study concluded that especially when prescribing drugs with ingredients like GS and CS, many patients’ pre-existing conditions must be considered, such as whether the patient has a glucose intolerance or not. Additionally, mineral toxication should be considered since the drugs contain minerals, and after the application of injected hyaluronan, complications should be considered.

Conclusion:

Clinical, controlled and comparative studies about the use of chondroprotective drugs must be performed to define the benefits of these drugs, if any, in order to determine the most suitable time for operative intervention.

The effect of sodium hyaluronate-chondroitin sulfate combined solution on cartilage formation in osteochondral defects of the rabbit knee: an experimental study

Objective

In focal cartilage lesions, multipotent mesenchymal stem cells in bone marrow are aimed to be moved into the defect area using subchondral drilling or microfracture method. However, repaired tissue insufficiently fills the defect area or cannot meet natural hyaline tissue functions, due to fibrous structure. We investigated the effect of a combined solution of sodium hyaluronate + chondroitin sulfate (HA+CS) administered intra-articularly after subchondral drilling on newly formed cartilage in rabbits with focal osteochondral defects.

Materials and methods

A total of 32 New Zealand White mature rabbits, whose weights ranged from 2.5 to 3 kg, were randomly divided into four groups. Full-thickness osteochondral defect was formed in the left-knee medial femur condyles of all rabbits. Subchondral drilling was then performed. The following treatment protocol was administered intra-articularly on knee joints on days 7, 14, and 21 after surgery: group 1, 0.3 mL combined solution of HA+CS (20 mg CS combined with 16 mg HA/mL); group 2, 0.3 mL HA (16 mg/mL); group 3, 0.3 mL CS (20 mg/mL); and group 4 (control group), 0.3 mL saline solution. In the sixth week, all animals were killed and then evaluated histopathologically and biochemically.

Results

There was significant articular cartilage formation in the HA+CS group compared to the HA, CS, and control groups. Hyaline cartilage formation was observed only in the HA+CS group. Cartilage-surface continuity and smoothness were significantly higher in the HA+CS and HA groups compared to the other groups. Normal cartilage mineralization was found to be significantly higher in the HA+CS group compared to the other groups. Increased levels of VEGFA and IL-1β in synovial fluid were observed in the HA+CS group.

Conclusion

After subchondral drilling, intra-articular HA-CS combination therapy is a good choice to promote better quality new cartilage-tissue formation in the treatment of focal osteochondral defects.

Healing potential of the cartilage correlates with location on the femoral head: a basic research using a rabbit model

PURPOSE

The purpose of this study is to investigate whether healing potential of the femoral cartilage differs according to the site of injury in a rabbit, and whether poor potential of the cartilage repair correlates with the injured site which is not in contact with acetabulum. Furthermore, the efficacy of intraarticular injection of hyaluronic acid into the hip for the cartilage with lower healing potential was evaluated.

METHODS

Male Japanese white rabbits were used in this study. Via the posterolateral approach, the articular capsule was incised and a 4 × 4 mm chondral defect was made at the load-bearing area (group A) or at head-neck junction (group B), and intraarticular injection of hyaluronic acid was performed to the group B model (group C).

RESULTS

In group A, histological evaluation at 8 weeks revealed that the chondral defect was filled with cartilaginous tissue. However, in group B, the chondral defect was not filled with any tissue and subchondral bone was exposed. In group C, the defect was filled with synovial-like tissue, and smooth surface was reacquired macroscopically. According to the ICRS score, significant differences were detected between group A and group B, group A and group C, and group B and group C. There were no differences in the radiographic findings among the 3 groups.

CONCLUSIONS

The cartilage at head-neck junction of the femoral head had poorer healing potential than that at load-bearing area. Administration of HA could be promising for preventing progression of cartilage degeneration even at head-neck junction.

The mechanism of action for hyaluronic acid treatment in the osteoarthritic knee: a systematic review

BACKGROUND

Knee osteoarthritis (OA) is one of the leading causes of disability within the adult population. Current treatment options for OA of the knee include intra-articular (IA) hyaluronic acid (HA), a molecule found intrinsically within the knee joint that provides viscoelastic properties to the synovial fluid. A variety of mechanisms in which HA is thought to combat knee OA are reported in the current basic literature.

METHODS

We conducted a comprehensive literature search to identify currently available primary non-clinical basic science articles focussing on the mechanism of action of IA-HA treatment. Included articles were assessed and categorized based on the mechanism of action described within them. The key findings and conclusions from each included article were obtained and analyzed in aggregate with studies of the same categorical assignment.

RESULTS

Chondroprotection was the most frequent mechanism reported within the included articles, followed by proteoglycan and glycosaminoglycan synthesis, anti-inflammatory, mechanical, subchondral, and analgesic actions. HA-cluster of differentiation 44 (CD44) receptor binding was the most frequently reported biological cause of the mechanisms presented. High molecular weight HA was seen to be superior to lower molecular weight HA products. HA derived through a biological fermentation process is also described as having favorable safety outcomes over avian-derived HA products.

CONCLUSIONS

The non-clinical basic science literature provides evidence for numerous mechanisms in which HA acts on joint structures and function. These actions provide support for the purported clinical benefit of IA-HA in OA of the knee. Future research should not only focus on the pain relief provided by IA-HA treatment, but the disease modification properties that this treatment modality possesses as well.

Efficacy study of two novel hyaluronic acid-based formulations for viscosupplementation therapy in an early osteoarthrosic rabbit model

Viscosupplementation (VS) is a therapy for osteoarthrosis (OA) consisting of repetitive intra-articular injections of hyaluronic acid (HA). It is known to be clinically effective in relieving pain and increasing joint mobility by restoring joint homeostasis. In this study, the effects of two novel HA-based VS hydrogel formulations were assessed and challenged against a pure HA commercial formulation for the first time and this in a rabbit model of early OA induced by anterior cruciate ligament transection (ACLT). The first formulation tested was a hybrid hydrogel composed of HA and reacetylated chitosan, a biopolymer considered to be chondroprotective, assembled thanks to an ionic shielding. The second formulation consisted of a novel HA polymer grafted with antioxidant molecules (HA-4AR) aiming at decreasing OA oxidative stress and increasing HA retention time in the articulation. ACLT was performed on rabbits in order to cause structural changes comparable to traumatic osteoarthrosis. The protective effects of the different formulations were observed on the early phase of the pathology in a full randomized and blinded manner. The cartilage, synovial membrane, and subchondral bone were evaluated by complementary investigation techniques such as gross morphological scoring, scanning electron microscopy, histological scoring, and micro-computed tomography were used. In this study, ACLT was proven to successfully reproduce early OA articular characteristics found in humans. HA and HA-4AR hydrogels were found to be moderately protective for cartilage as highlighted by μCT. The HA-4AR was the only formulation able to decrease synovial membrane hypertrophy occurring in OA. Finally, the hybrid HA-reacetylated chitosan hydrogel surprisingly led to increased subchondral bone remodeling and cartilage defect formation. This study shows significant effects of two innovative HA modification strategies in an OA rabbit model, which warrant further studies toward more effective viscosupplementation formulations.

Lubricin/Proteoglycan 4 Binding to CD44 Receptor: A Mechanism of the Suppression of Proinflammatory Cytokine-Induced Synoviocyte Proliferation by Lubricin

OBJECTIVE

To evaluate the binding of recombinant human proteoglycan 4 (rhPRG4) to CD44 receptor and its consequences on cytokine-induced synoviocyte proliferation.

METHODS

The binding of rhPRG4 to CD44 and competition with high molecular weight (HMW) hyaluronic acid (HA) was evaluated using a direct enzyme-linked immunosorbent assay (ELISA) and surface plasmon resonance. Sialidase A and O-glycosidase digestion of rhPRG4 was performed, and CD44 binding was evaluated using ELISA. Rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLS) were stimulated with interleukin-1β (IL-1β) or tumor necrosis factor α (TNFα) for 48 hours in the presence or absence of rhPRG4 or HMW HA at 20, 40, and 80 μg/ml, and cell proliferation was measured. The contribution of CD44 was assessed by coincubation with a CD44 antibody (IM7). The antiproliferative effect of rhPRG4 was investigated following treatment of PRG4(-/-) mouse synoviocytes with IL-1β or TNFα in the presence or absence of IM7.

RESULTS

Recombinant human PRG4 bound CD44 and interfered with the binding of HMW HA to CD44. Removal of sialic acid and O-glycosylations significantly increased CD44 binding by rhPRG4 (P < 0.001). Both rhPRG4 and HMW HA at 40 and 80 μg/ml significantly suppressed IL-1β-induced proliferation of RA FLS (P < 0.05). Recombinant human PRG4 at 20, 40, and 80 μg/ml significantly suppressed TNFα-induced RA FLS proliferation (P < 0.05). CD44 neutralization reversed the effect of rhPRG4 on IL-1β- and TNFα-stimulated RA FLS and the effect of HMW HA on IL-1β-stimulated RA FLS. Recombinant human PRG4 inhibited cytokine-induced proliferation of PRG4(-/-) synoviocytes, which could be prevented by blocking CD44.

CONCLUSION

PRG4 (lubricin) is a novel putative ligand for CD44 and may control synoviocyte overgrowth in inflammatory arthropathies via a CD44-mediated mechanism.

Intra-articular resveratrol injection prevents osteoarthritis progression in a mouse model by activating SIRT1 and thereby silencing HIF-2α

We investigated the feasibility of the intra-articular injection of resveratrol for preventing the progression of existing cartilage degeneration in a mouse model of osteoarthritis (OA). The effects of resveratrol on the expression of silent information regulator 2 type 1 (SIRT1), hypoxia-inducible factor-2α (HIF-2α) and catabolic factors in OA cartilage was explored. OA was induced in the mouse knee via destabilization of the medial meniscus (DMM). Resveratrol was injected weekly into the operated knee beginning 4 weeks after surgery. The OA phenotype was evaluated via histological and immunohistochemical analyses at 8 weeks after DMM. Western blot analysis was performed to identify whether resveratrol modulated the interleukin (IL)-1β-induced expression of HIF-2α in human chondrocytes. Histologically, resveratrol treatment preserved the structural homeostasis of the articular cartilage and the subchondral bone. Following resveratrol injection, the expression of collagen type II was retained, but the expression of inducible nitric oxide synthase and matrix metalloproteinase-13 was reduced in OA cartilage. Moreover, the administration of resveratrol significantly induced the activation of SIRT1 and the inhibition of HIF-2α expression in mouse OA cartilage and in IL-1β-treated human chondrocytes. These findings indicate that the intra-articular injection of resveratrol significantly prevents the destruction of OA cartilage by activating SIRT1 and thereby suppressing the expression of HIF-2α and catabolic factors.

A hyaluronic acid-salmon calcitonin conjugate for the local treatment of osteoarthritis: chondro-protective effect in a rabbit model of early OA

Osteoarthritis (OA) is characterized by chronic degeneration of joints, involving mainly the articular cartilage and the underlying bone, and severely impairing the quality of life of the patient. Although with limited efficacy, currently available pharmacological treatments for OA aim to control pain and to retard disease progression. Salmon calcitonin (sCT) is a drug which has been shown to have therapeutic effects in experimental arthritis by inhibiting both bone turnover and cartilage degradation and reducing the activities of matrix metalloproteinases (MMP). High molecular weight hyaluronic acid (HA) is used as a lubricant in OA therapy, and, interestingly, HA polymers may normalize the levels of MMP-1, -3 and -13. We demonstrated that sCT rapidly clears from the knee joint of rat animal model, after intra-articular (i.a.) administration, and it induces systemic effects. Here, sCT was conjugated to HA (200kDa) with the aim of prolonging the residence time of the polypeptide in the joint space by reducing its clearance. An aldehyde derivative of HA was used for N-terminal site-selective coupling of sCT. The activity of sCT was preserved, both in vitro and in vivo, after its conjugation and the i.a. injection of HA-sCT did not trigger any systemic effects in rats. The efficacy of HA-sCT treatment was tested in a rabbit OA model and clear chondro-protective effect was proven by macro- and microscopic assessments and histological findings. Our results indicate that HAylation of sCT increases the size of the polypeptide in a stable covalent manner and delays its passage into the blood stream. We conclude that HA conjugation prolongs the anti-catabolic effects of sCT in joint tissues, including the synovial membrane and cartilage.

Potential role of hyaluronic acid on bone in osteoarthritis: matrix metalloproteinases, aggrecanases, and RANKL expression are partially prevented by hyaluronic acid in interleukin 1-stimulated osteoblasts

OBJECTIVE

To determine the effect of hyaluronic acid (HA) on proteolytic enzymes and bone remodeling mediators induced by interleukin 1β (IL-1β) and related to cartilage catabolism in murine osteoblasts.

METHODS

Osteoblasts were obtained from Swiss mice and cultured for 3 weeks. HA-treated osteoblasts were incubated with 100 μg/ml HA during the last week of culture, then stimulated with IL-1β (10 ng/ml) for 24 h. The expression of matrix metalloproteinases 3 and 13 (MMP-3 and MMP-13), ADAMTS-4 and ADAMTS-5, tissue inhibitor of metalloproteinases (TIMP), osteoprotegerin, and receptor activator of nuclear factor-κB ligand (RANKL) was determined by real-time polymerase chain reaction. MMP-3 and MMP-13 release was assessed by Western blot analysis.

RESULTS

IL-1β increased the mRNA levels of MMP-3 and MMP-13 and ADAMTS-4 and ADAMTS-5 and release of MMP-3 and MMP-13. Seven days of HA treatment significantly prevented the IL-1β-increased mRNA levels of MMP-3 (-61%, p < 0.01), MMP-13 (-56%, p < 0.01), ADAMTS-4 (-58%, p < 0.05), ADAMTS-5 (-52%, p < 0.01), and RANKL (-49%, p < 0.05), but not TIMP. As well, IL-1β-induced production of MMP-3 and MMP-13 was inhibited, by 27% (p < 0.01) and 40% (p < 0.01), respectively.

CONCLUSION

In an inflammatory context in murine osteoblasts, HA can inhibit the expression of MMP and ADAMTS. Because HA can counteract the production of these mediators in chondrocytes, its beneficial effect in osteoarthritis may be due to its action on cartilage and subchondral bone.

Periodic knee injections of collagen tripeptide delay cartilage degeneration in rabbit experimental osteoarthritis

Introduction

Collagen peptides have been reported to possess various biological activities for various cell types. The purposes of this study were, first, to examine the therapeutic effects of collagen tripeptide (Ctp) in rabbit osteoarthritis and, second, to explore a synergetic effect with hyaluronan (HA).

Methods

Osteoarthritis was induced by anterior cruciate ligament transection of the right knee in 72 Japanese white rabbits and they were divided into four groups (control, Ctp, HA and Ctp/HA). Each material was injected weekly into the knee, and knee joint samples were collected 5, 10 and 15 weeks after surgery. Macroscopic and histomorphological analyses of cartilage were conducted. Expression of type II collagen and matrix metalloproteinase-13 was also analyzed immunohistochemically. A Tukey's honestly significant difference test was used to evaluate the statistical significance of difference in the macroscopic, histological and immnohistochemical results.

Results

All treatment groups exhibited slightly higher resistance to the progression of osteoarthritis than the control group macroscopically 15 weeks after surgery. Histologically, intra-articular injection of Ctp significantly reduced cartilage degradation 10 weeks after surgery, and Ctp/HA significantly reduced it 5 weeks after surgery in comparison with the control. Immunohistochemically, both Ctp-treated and Ctp/HA-treated groups had significantly increased type II collagen-positive chondrocytes at the fifth week after the surgery, although the numbers of matrix metalloproteinase-13-positive chondrocytes were not affected.

Conclusion

Periodical injections of Ctp and Ctp/HA delayed progression of cartilage degeneration of early osteoarthritis induced by anterior cruciate ligament transection in rabbits. This effect appears to be exerted by promotion of type II collagen synthesis predominantly.

An intra-articular salmon calcitonin-based nanocomplex reduces experimental inflammatory arthritis

Prolonged inappropriate inflammatory responses contribute to the pathogenesis of rheumatoid arthritis (RA) and to aspects of osteoarthritis (OA). The orphan nuclear receptor, NR4A2, is a key regulator and potential biomarker for inflammation and represents a potentially valuable therapeutic target. Both salmon calcitonin (sCT) and hyaluronic acid (HA) attenuated activated mRNA expression of NR4A1, NR4A2, NR4A3, and matrix metalloproteinases (MMPs) 1, 3 and 13 in three human cell lines: SW1353 chondrocytes, U937 and THP-1 monocytes. Ad-mixtures of sCT and HA further down-regulated expression of NR4A2 compared to either agent alone at specific concentrations, hence the rationale for their formulation in nanocomplexes (NPs) using chitosan. The sCT released from NP stimulated cAMP production in human T47D breast cancer cells expressing sCT receptors. When NP were injected by the intra-articular (I.A.) route to the mouse knee during on-going inflammatory arthritis of the K/BxN serum transfer model, joint inflammation was reduced together with NR4A2 expression, and local bone architecture was preserved. These data highlight remarkable anti-inflammatory effects of sCT and HA at the level of reducing NR4A2 mRNA expression in vitro. Combining them in NP elicits anti-arthritic effects in vivo following I.A. delivery.

Combined effect of subchondral drilling and hyaluronic acid with/without diacerein in full-thickness articular cartilage lesion in rabbits

The osteochondral healing potential of hyaluronic acid (HA) plus diacerein was evaluated in subchondral-drilling- (SCD-) induced fibrocartilage generation in rabbits. A full-thickness chondral defect was created along the patellar groove of both knees and then SCD was subsequently performed only in the left knee. A week later, the rabbits were allocated into 3 groups to receive weekly intra-articular (IA) injection for 5 weeks with normal saline solution (NSS) (group 1) or with HA (group 2 and group 3). Starting at the first IA injection, rabbits were also gavaged daily for 9 weeks with NSS (group 1 and group 2) or with diacerein (group 3). The animals were then sacrificed for evaluation. The newly formed tissue in SCD lesions showed significantly better histological grading scale and had higher content of type II collagen in HA-treated group compared to NSS control. In addition, adding oral diacerein to HA injection enhanced healing potential of HA.

Contralateral cruciate survival in dogs with unilateral non-contact cranial cruciate ligament rupture

BACKGROUND

Non-contact cranial cruciate ligament rupture (CrCLR) is an important cause of lameness in client-owned dogs and typically occurs without obvious injury. There is a high incidence of bilateral rupture at presentation or subsequent contralateral rupture in affected dogs. Although stifle synovitis increases risk of contralateral CrCLR, relatively little is known about risk factors for subsequent contralateral rupture, or whether therapeutic intervention may modify this risk.

METHODOLOGY/PRINCIPAL FINDINGS

We conducted a longitudinal study examining survival of the contralateral CrCL in client-owned dogs with unilateral CrCLR in a large baseline control population (n = 380), and a group of dogs that received disease-modifying therapy with arthroscopic lavage, intra-articular hyaluronic acid and oral doxycycline (n = 16), and were followed for one year. Follow-up in treated dogs included analysis of mobility, radiographic evaluation of stifle effusion and arthritis, and quantification of biomarkers of synovial inflammation. We found that median survival of the contralateral CrCL was 947 days. Increasing tibial plateau angle decreased contralateral ligament survival, whereas increasing age at diagnosis increased survival. Contralateral ligament survival was reduced in neutered dogs. Our disease-modifying therapy did not significantly influence contralateral ligament survival. Correlative analysis of clinical and biomarker variables with development of subsequent contralateral rupture revealed few significant results. However, increased expression of T lymphocyte-associated genes in the index unstable stifle at diagnosis was significantly related to development of subsequent non-contact contralateral CrCLR.

CONCLUSION

Subsequent contralateral CrCLR is common in client-owned dogs, with a median ligament survival time of 947 days. In this naturally occurring model of non-contact cruciate ligament rupture, cranial tibial translation is preceded by development of synovial inflammation. However, treatment with arthroscopic lavage, intra-articular hyaluronic acid and oral doxycycline does not significantly influence contralateral CrCL survival.