Hylan G-F 20 maintains cartilage integrity and decreases osteophyte formation in osteoarthritis through both anabolic and anti-catabolic mechanisms

Histopathological Interpretation of TMJ Osteophyte: Report and Review

Introduction

Osteophytes are osseocartilaginous structures which are commonly found in common degenerative joint diseases. It can be free or attached to nature. There is a paucity of information in the literature regarding the histopathological interpretation of osteophytes in Temporomandibular Joint (TMJ).

Purpose

To report the incidental finding of osteophytes in cases of chronic protracted TMJ dislocation.

Material and Method

To present case of an elderly 72-year-old female and a 35-year-old male with chronic protracted TMJ dislocation who were treated surgically for their condition with an incidental finding of an osteophyte in TMJ intraoperatively.

Result

The histopathological examination revealed fibrocartilaginous core tissue surrounded by bone formation due to dystrophic calcification.

Conclusion

The microscopic examination is mandatory in order to study and understand the pathophysiology of an osteophyte. This study presents rare histopathological evidence of an osteophyte. It reflects the process of its formation and the possibilities of fate of an osteophyte in TMJ.

Machine learning-based predictive modeling, virtual screening and biological evaluation studies for identification of potential inhibitors of MMP-13

Matrix Metalloproteinase-13 (MMP-13) is a collagenase that regulates the homeostasis of the extracellular matrix (ECM) and basement membrane, as well as the breakdown of type II collagen. Recent research studies on the molecular and cellular mechanisms of cartilage degradation suggest that MMP-13 overexpression triggers osteoarthritis and is considered a promising target for osteoarthritis treatment. The present work employs machine learning-based virtual screening and structure-based rational drug design approaches to identify potential inhibitors of MMP-13 with diverse chemical scaffolds. The twelve top-scoring screened compounds were subjected to biological evaluation to validate the robustness and predictive modeling of ML-based Virtual Screening. It was observed that eight compounds exhibited approximately 44%-60% inhibition at 0.1 µM concentration, and the IC50 lies in the range of 1.9-2.3 µM against MMP-13. Interestingly, two of the compounds, DP01473 and RH01617, showed potent dose-dependent inhibitory activity. Compound DP01473 inhibited MMP-13 by 44%, 50%, and 70%, while compound RH01617 inhibited MMP-13 by 54%, 55%, and 57% at 0.1 μM, 1 μM, and 10 μM concentrations, respectively, and can be further optimized for the design and development of more potent MMP-13 inhibitors.Communicated by Ramaswamy H. Sarma.

Human Adipose- and Amnion-Derived Mesenchymal Stromal Cells Similarly Mitigate Osteoarthritis Progression in the Dunkin Hartley Guinea Pig

BACKGROUND

Clinical trials are currently underway to investigate the efficacy of intra-articular administration of mesenchymal stromal cells (MSCs) to mitigate osteoarthritis (OA) progression in the knee. Although multiple MSC sources exist, studies have yet to determine whether differences in therapeutic efficacy exist between them.

PURPOSE

To compare the ability of intra-articularly injected adipose-derived MSCs (AD-MSCs) and amnion-derived MSCs (AM-MSCs) to mitigate the progression of knee OA in a small animal model of spontaneous OA, as well as to compare the therapeutic potential of MSCs in hyaluronic acid (HA) and in HA only with saline (OA) controls.

STUDY DESIGN

Controlled laboratory study.

METHODS

Injections of AD-MSCs or AM-MSCs suspended in HA or HA only were performed in the rear stifle joints of 3-month-old Dunkin Hartley guinea pigs (DHGPs). Repeat injections occurred at 2 and 4 months after the initial injection in each animal. Contralateral limbs received saline injections and served as untreated controls. Subsequently, joints were analyzed for osteoarthritic changes of the cartilage and subchondral bone via histologic and biochemical analyses. To evaluate MSC retention time in the joint space, DHGPs received a single intra-articular injection of fluorescently labeled AD-MSCs or AM-MSCs, and the fluorescence intensity was longitudinally tracked via an in vivo imaging system.

RESULTS

No statistically significant differences in outcomes were found when comparing the ability of AD-MSCs and AM-MSCs to mitigate OA. However, the injection of AD-MSCs, AM-MSCs, and HA-only treatments more effectively mitigated cartilage damage compared with that of saline controls by demonstrating higher amounts of cartilage glycosaminoglycan content and improved histological proteoglycan scoring while reducing the percentage of osteophytes present.

CONCLUSION

Intra-articular injection of AD-MSCs, AM-MSCs, or HA only was able to similarly mitigate the progression of cartilage damage and reduce the percentage of osteophytes compared with that of saline controls in the DHGP. However, this study was unable to establish the superiority of AD-MSCs versus AM-MSCs as a treatment to mitigate spontaneous OA.

CLINICAL RELEVANCE

MSCs demonstrate the ability to mitigate the progression of knee OA and thus may be used in a prophylactic approach to delay the need for end-stage treatment strategies.

Treatment of condylar osteophyte in temporomandibular joint osteoarthritis with muscle balance occlusal splint and long-term follow-up: A case report

BACKGROUND

Condylar osteophytes, a remodeling form of temporomandibular joint osteoarthritis (TMJ OA), mainly manifest as marginal angular outgrowths of the condyle. Previous researchers have advocated surgical removal of condylar osteophytes. Reports on the effect of occlusal splint on TMJ OA patients’ joints have mostly focused on treatment with this splint, which can reduce the absorption of the affected condyle and promote repair and regeneration. However, the effect of the splint on the dissolution of condylar osteophytes has not yet been reported.

CASE SUMMARY

A 68-year-old female patient suffered from occlusal discomfort with left facial pain for 2 years. Cone beam computed tomography showed a rare osteophyte on top of her left condyle. She was finally diagnosed with TMJ OA. The patient refused surgical treatment and received conservative treatment with a muscle balance occlusal splint. The pain experienced by the patient on the left side of her face was relieved, and her chewing ability recovered after treatment. The osteophyte dissolved, and the condylar cortex remained stable during long-term follow-up observations.

CONCLUSION

The muscle balance occlusal splint could be a noninvasive means of treating condylar osteophytes in TMJ OA patients.

Decision Algorithms for the Retreatment with Viscosupplementation in Patients Suffering from Knee Osteoarthritis: Recommendations from the EUROpean VIScosupplementation COnsensus Group (EUROVISCO)

Background Viscosupplementation (VS) is a symptomatic treatment of knee osteoarthritis. Although systematic reviews of its repeat use showed favorable benefit/risk ratio, no study has focused on the indication of retreatment. Methods A task force was created to look at issues regarding retreatment with VS in knee osteoarthritis. An attempt was made to reach consensus on several issues: (1) to define treatment "success" and "failure," (2) to determine when to retreat patients successfully treated by a previous VS, (3) to determine how to retreat patients in whom VS failed, (4) to define what to do in case of adverse reaction following previous VS, and (5) to examine the interests of soluble biomarkers to manage retreatment. After debate and review of literature the working group voted on 88 issues. Two "decision trees" were built based on the results of the votes. Results In case of failure, the authors draw attention to the need of a rigorous clinical and radiological analysis, and consider evidence-based medicine. When VS was previously successful, retreatment can be considered after recurrence or increase in pain. However, in subjects with high risk of disease progression, in young patients, and in professional sportsmen, retreatment could be considered systematically, because of the probability of hyaluronic acid to slow osteoarthritis progression. Evidence on soluble biomarkers was not considered as enough strong to support their use as decision tools for patient retreatment. Conclusion The decision algorithms are intended to facilitate consideration of the therapeutic options, in patients with knee osteoarthritis previously treated with VS.

Ultrastructural change of the subchondral bone increases the severity of cartilage damage in osteoporotic osteoarthritis of the knee in rabbits

Osteoporotic osteoarthritis is a phenotype of osteoarthritis (OA) manifested as fragile and osteoporotic subchondral bone. However, the ultrastructural features of subchondral bone in osteoporosis OA have not been determined. The study was aimed to investigate the ultrastructural dynamic changes of subchondral bone in osteoporotic OA model and how the ultrastructural damage in the subchondral bone caused by osteoporosis deteriorated the cartilage damage in OA. Eighteen rabbits were equally randomized to three groups, including the control, the OA and the osteoporotic OA groups. The structural changes of cartilage were evaluated by HE and safranin-O fast green staining, the Mankin's grading system was used to assess the stage of OA progression. And microstructural or ultrastructural changes in subchondral bone were assessed by micro-computed tomography or by scanning electron microscopy. According to the changes of cartilage histopathology, the OA group was in the early pathological stage of OA while the osteoporotic OA group was in the middle stage of OA based on Mankin's grading system. In addition, the damage of cartilage surface, reduction in the number of chondrocytes and the matrix staining were more increased in the osteoporotic OA group compared to the OA group. Compared to the OA group, the subchondral bone in the microstructure and ultrastructure in the osteoporotic OA group showed more microfracture changes in trabecular bone with more destructions of the tree-like mesh. Moreover, the collagen fibers were random rough with a fewer amount of bone lacunae in subchondral cortical plate in the osteoporotic OA group compared to the OA group. These findings indicated that the subchondral bone ultrastructure in the osteoporotic OA model was characterized by the destruction of the network structure and collagen fibers. The subchondral bone ultrastructural damage caused by osteoporosis may change mechanical properties of the upper cartilage and aggravate OA cartilage. Therefore, early diagnosis and treatment of osteoporosis is of great significance to prevent early OA from further developing osteoporotic OA.

New insights on the MMP-13 regulatory network in the pathogenesis of early osteoarthritis

Osteoarthritis (OA) is the most common joint disorder and affects approximately half of the aged population. Current treatments for OA are largely palliative until the articular cartilage has been deeply damaged and irreversible morphological changes appear. Thus, effective methods are needed for diagnosing and monitoring the progression of OA during its early stages when therapeutic drugs or biological agents are most likely to be effective. Various proteinases involved in articular cartilage degeneration in pre-OA conditions, which may represent the earliest reversible measurable changes, are considered diagnostic and therapeutic targets for early OA. Of these proteinases, matrix metalloproteinase 13 (MMP-13) has received the most attention, because it is a central node in the cartilage degradation network. In this review, we highlight the main MMP-13-related changes in OA chondrocytes, including alterations in the activity and expression level of MMP-13 by upstream regulatory factors, DNA methylation, various non-coding RNAs (ncRNAs), and autophagy. Because MMP-13 and its regulatory networks are suitable targets for the development of effective early treatment strategies for OA, we discuss the specific targets of MMP-13, including upstream regulatory proteins, DNA methylation, non-coding RNAs, and autophagy-related proteins of MMP-13, and their therapeutic potential to inhibit the development of OA. Moreover, the various entities mentioned in this review might be useful as early biomarkers and for personalized approaches to disease prevention and treatment by improving the phenotyping of early OA patients.

Corticosteroid transdermal delivery significantly improves arthritis pain and functional disability

Arthritis is characterized by pain and functional limitation affecting the patients' quality of life. We performed a clinical study to investigate the efficacy of a betamethasone valerate medicated plaster (Betesil) in improving pain and functional disability in patients with arthritis and osteoarthritis. We enrolled 104 patients affected by osteoarthritis (n = 40) or arthritis (n = 64) in different joints. Patients received diclofenac sodium cream (2 g, four times a day) or a 2.25-mg dose of Betesil applied to the painful joint every night before bedtime for 10 days. Pain and functional disability were assessed, by the Visual Analogue Scale (VAS) and Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) scores. Redness was assessed by clinical inspection, and edema by the "fovea sign" method. C-reactive protein (CRP) was also measured; CRP can be used to cost-effectively monitor the pharmacological treatment efficacy and is increased during the acute-phase response, returning to physiological values after tissue recovery and functional restoration. All measurements were at baseline and at 10-day follow-up. At 10-day follow-up, a greater improvement in VAS and WOMAC pain and WOMAC stiffness and functional limitation scores from baseline was observed in patients treated with Betesil compared with diclofenac (all p < 0.01). At 10-day follow-up, improvement in redness, edema, and CRP levels from baseline was also greater in patients treated with Betesil compared with diclofenac (all p < 0.01). This study demonstrates the safety and efficacy of transdermal delivery of betamethasone valerate in patients affected by arthritis and osteoarthritis.

Intra-articular hyaluronic acid in the treatment of knee osteoarthritis: a Canadian evidence-based perspective

Osteoarthritis (OA) is a chronic condition characterized by a loss of joint cartilage and is a major cause of disability in Canada, with an estimated CN$195 billion annual cost. Knee OA leads to persistent pain and loss of function, and treatment goals primarily focus on symptom relief and retention of function. Intra-articular hyaluronic acid (IAHA) has therapeutic benefits, and numerous recently published meta-analyses (MAs) and commentaries have highlighted new evidence on the role of IAHA therapy for knee OA. A diverse, multidisciplinary group of specialists met independently in closed sessions to review findings from eight MAs with literature search end dates no earlier than 2012 to address controversies surrounding IAHA therapy for mild-to-moderate knee OA within the Canadian treatment context. Outcomes from a total of eight MAs were reviewed, and consistent and statistically significant improvements in pain, function and stiffness up to 26 weeks were found with IAHA therapy compared with IA placebo or controls, regardless of MA size or trial quality. These findings are in line with those of a Cochrane review, another recent systematic review and patient satisfaction survey. Overall, three MAs reported outcomes based on molecular weight (MW), with the two reporting effect sizes showing significantly improved pain outcomes for higher compared with lower MW HAs. Recent evidence suggests that HA therapy is well tolerated with no increased risk of serious adverse events compared with placebo and the full therapeutic effect of IAHA therapy appears to have considerable clinical importance, consisting of the combined IA placebo and HA therapeutic effects. IAHA therapy is a well-tolerated and effective option for patients with mild-to-moderate knee OA failing first-line pharmacological therapy.

Inhibition of chronic prostate inflammation by hyaluronic acid through an immortalized human prostate stromal cell line model

Benign prostatic hyperplasia (BPH) is the most common urologic disease among elderly men. A well-established in vitro cell model is required to determine the therapeutic mechanism of BPH inflammation. In this study, we attempted to establish an immortalized human prostate stromal cell line by transfecting with HPV-16 E6/E7 and designated as ihPSC. No significant difference was found in fibroblast-like morphology between primary hPSC and ihPSC. The ihPSC possessed a significantly higher cell proliferation rate than primary hPSC. The prostate-specific markers and proteins including cytoskeleton (α-SMA and vimentin) and smooth muscle (calponin), especially the androgen receptor (AR) were also examined in ihPSC, almost identical to the primary hPSC. To create an in vitro model featuring chronic prostatic inflammation, ihPSC was stimulated with IFN-γ+IL-17 and then treated with the high molecular weight hyaluronic acid hylan G-F 20 as an alternative strategy for inhibiting BPH inflammation. Hylan G-F 20 could dose-dependently diminish the inflammation-induced proliferation in ihPSC. The enhanced expressions of inflammatory molecules including IL-1β, IL-6, IL-8, cyclooxygenase 2 (COX2), inducible nitrogen oxide synthase (iNOS), and Toll-like receptor 4 (TLR4) were all abolished by hylan G-F 20. For inflammatory signaling, hylan G-F 20 can also diminish the IFN-γ+IL-17-increased expression of iNOS and p65 in ihPSC. These findings suggest that ihPSC could provide a mechanism-based platform for investigating prostate inflammation. The hylan G-F 20 showed strong anti-inflammatory effects by decreasing inflammatory cytokines and signalings in the ihPSC, indicating its therapeutic potentials in BPH treatment in the future.

Evaluation of the effect of oral administration of collagen peptides on an experimental rat osteoarthritis model

Collagen is an extracellular matrix protein present in the skin, tendon, cartilage and bone. Collagen peptides (CP) are produced by the hydrolysis of gelatin (heat-denatured collagen) by proteases and are utilized as a component of nutraceuticals. The current study investigated the effect of CP on the articular cartilage of OA by evaluating the serum levels of biomarkers (CTX-II for type II collagen degradation and CPII for type II collagen synthesis), histopathological changes (Mankin score, based on the toluidine blue staining of proteoglycans), and immunohistochemical staining of matrix metalloproteinase (MMP)-13 and type II collagen, using a rat experimental osteoarthritis (OA) model. Anterior cruciate ligament transection (ACLT) was performed on the right knee joint to surgically induce OA. Animals were divided into four groups: Control group (Control), sham-operated group (Sham), ACLT group without collagen peptide (ACLT group) and ACLT group with oral administration of CP (CP group). ACLT induced histological damages and significantly increased the Mankin score (P<0.05). However, CP administration markedly suppressed the Mankin score, although this difference was not significant. In addition, serum CTX-II levels were significantly decreased in CP group compared with those in the ACLT group (P<0.05). By contrast, serum CPII levels did not differ significantly among the four groups. Moreover, immunohistochemical staining of type II collagen and MMP-13 (an important type II collagen-degrading enzyme) indicated that the amount of type II collagen increased, whereas the number of MMP-13 positive chondrocytes decreased in the CP group compared with ACLT group. These observations suggest that CP has the potential to exert chondroprotective action on OA by inhibiting MMP-13 expression and type II collagen degeneration.

An in vivo cross-linkable hyaluronan gel with inherent anti-inflammatory properties reduces OA cartilage destruction in female mice subjected to cruciate ligament transection

OBJECTIVE

To explore the possibility of cartilage protection in osteoarthritis (OA) by intraarticular injection of a chemically modified hyaluronan (HA) gel and investigate whether the chemical modifications provide intrinsic anti-inflammatory activity.

METHOD

OA was induced in C57BL/6 mice by anterior cruciate ligament transection (ACLT) and HA gel or carbazate-modified component was injected intra-articularly. Assessment of cartilage rescue was performed by histology, immunohistochemistry and TUNEL analysis. Serum levels of proinflammatory cytokines were evaluated with cytometric bead array, measuring IL-1β, TNF, IFN-γ, KC/CXCL1 and MCP-1.

RESULTS

Intraarticular injection of the HA gel showed significantly reduced cartilage destruction and decreased osteophyte formation. Besides the biological and biomechanical effects of HA, we investigated lipid peroxidation products as an alternative inflammatory and potential mechanism contributing to OA. To address this, injection of the carbazate-modified component alone was performed, which also demonstrated a cartilage-saving effect. Besides the cartilage amelioration effects, decreased apoptosis, 4-hydroxynonenal (4-HNE) and MHC class II staining was recorded. No changes in serum levels of proinflammatory cytokines were detected.

CONCLUSION

We have shown that the HA gel has an anti-destructive effect on articular cartilage (AC). Our results demonstrated that the carbazate-modified component could suppress apoptotic events, potentially by quenching of ROS/LPO products such as 4-HNE in OA joints. Modification of the HA molecule offers opportunities to introduce (covalent) coupling of additional molecules to the gel, with controlled retention and subsequent release in the joint.

Imaging Guidance Improves the Results of Viscosupplementation with HANOX-M-XL in Patients with Ankle Osteoarthritis: Results of a Clinical Survey in 50 Patients Treated in Daily Practice

BACKGROUND

The objective of this survey was to assess retrospectively the interest of performing viscosupplementation using imaging guidance in patients suffering from ankle osteoarthritis (OA).

PATIENTS AND METHODS

This is a multicenter retrospective survey using a standardized questionnaire. Fifty patients suffering from ankle OA and treated, in daily clinical practice, with a single intra-articular injection of a novel viscosupplement made of a combination of a non-animal cross-linked hyaluronan and mannitol, HANOX M-XL, were included in the survey. The injection procedure (imaging or landmark guidance), demographic data, patient’s self-evaluation of pain, satisfaction, treatment efficacy, and tolerability were collected. Predictive factors of both efficacy and patient’s satisfaction were investigated.

RESULTS

The percentages of patients very satisfied/satisfied and not really satisfied/dissatisfied with the treatment were 68% and 32%, respectively. Efficacy was rated as very good, good, moderate, and poor by 38%, 30%, 12%, and 20% of the cases, respectively. Efficacy was unrelated to gender and age and was highly correlated with pain score (P < 0.0001). In satisfied patients, the decrease in consumption of analgesics/non-steroidal anti-inflammatory drugs was >75% in 64% of the cases. Efficacy was significantly different with regard to imaging guidance. There was a statistically significant difference in efficacy and satisfaction between landmark-guided and imaging-guided injections (P = 0.02). The success rate was 2.3 times higher in the imaging-guided group than in the landmark-guided group. No significant difference was found between patients injected under fluoroscopy or ultrasound guidance, despite a trend favoring ultrasound (P = 0.09). Tolerability was rated as very good/good in 47 patients, moderate in two, and poor in one and was unrelated to the type of guidance.

CONCLUSION

This preliminary study suggests that the use of imaging guidance significantly optimizes the success rate of ankle viscosupplementation. No safety concern was observed.

LEVEL OF EVIDENCE

III.

Safety and efficacy of intra-articular injections of a combination of hyaluronic acid and mannitol (HAnOX-M) in patients with symptomatic knee osteoarthritis: Results of a double-blind, controlled, multicenter, randomized trial

BACKGROUND

To compare both safety and efficacy of a novel intra-articular viscosupplement made of intermediate molecular weight (MW) hyaluronic acid (HA) mixed with high concentration of mannitol with a marketed high MW HA, in patients with knee osteoarthritis (OA).

METHODS

Patients with symptomatic knee OA, with radiological OARSI grades 1 to 3, were enrolled in a controlled, double-blind, parallel-group, non-inferiority trial. They were randomized to receive three intra-articular injections, at weekly intervals, of either HAnOX-M made of a combination of HA (MW one to 1.5MDa, 31mg/2ml) and mannitol (70mg/2ml) or Bio-HA (MW 2.3 to 3.6MDa, 20mg/2ml). The primary outcome was six-month change in the WOMAC pain subscale (0 to 20). Sample size was calculated according to a non-inferiority margin of 1.35. Secondary endpoints included six-month change in function and walking pain, analgesic consumption and safety.

RESULTS

The intention-to-treat (ITT) and per-protocol (PP) populations consisted of 205 and 171 patients. HAnOX-M and Bio-Ha groups did not differ statistically at baseline. The primary analysis was conducted in the PP population, then in the ITT population. The average WOMAC pain score at baseline was 9.5 in both groups. Mean (SD) variations in WOMAC pain score were -4.4 (3.8) and -4.5 (4.3) mm, for HAnOX and Bio-HA respectively, satisfying the claim for non-inferiority. Similar results were obtained for all other secondary endpoints.

CONCLUSION

Treatment with of HAnOX-M is effective to alleviate knee OA symptoms and to improve joint function over six months, with similar safety than conventional HA viscosupplement.

Standardized Follow-up of Patients with Symptomatic Knee Osteoarthritis Treated with a Single Intra-articular Injection of a Combination of Cross-Linked Hyaluronic Acid and Mannitol

OBJECTIVES

The objective of this study is to obtain pilot data from daily practice conditions of a viscosupplement made of a cross-linked high-molecular-weight hyaluronic acid (HA) combined with mannitol in patients with knee osteoarthritis (KOA).

METHODS

The data of 40 consecutive patients, 29 women and 11 men, who were prospectively followed up for 6 months, using a standardized procedure, were retrospectively analyzed. All patients have received a single intra-articular injection of HAnox-M-XL (4.4 mL), viscosupplement made of a cross-linked HA (16 mg/mL) + mannitol (35 mg/mL), in the target knee. The primary outcome was safety. The secondary end points included 3- and 6-month change in the WOMAC pain (0–50) and WOMAC total (0–240) and patient’s global assessment (PGA). Patient’s self-assessment of treatment efficacy (0–3) and analgesic consumption were obtained at months 3 and 6. An intent-to-treat analysis was performed.

RESULTS

Mean (SD) age was 60.7 (13.9) years, and mean BMI was 28.6 (5.0). Kellgren–Lawrence radiological grade was I/II and III/IV in 13 and 27 of the subjects, respectively. The average WOMAC pain and WOMAC total scores at baseline were 21.5 (9.8) and 89.9 (42.8), respectively. Thirty-nine patients completed the follow-up. HAnox-M-XL was well tolerated; two patients experienced knee pain after injection, which resolved within three days. No treatment-related severe adverse event was reported. Mean (SD) variations in WOMAC pain and WOMAC total scores were −8.2 (8.9) and −38.4 (35.6), respectively, at month 6 (P = 0.001). PGA decreased from 5.5 (2.0) to 3.0 (2.2) (P = 0.006). Efficacy was rated as good or very good in 76.9% of the cases. Most of the regular analgesics users decreased their consumption.

CONCLUSION

Treatment with one injection of 4.4 mL HAnox-M-XL is effective to alleviate KOA symptoms over six months, without safety concern. Controlled trials are needed to confirm these pilot data.

Intra-articular therapies for osteoarthritis

INTRODUCTION

Conventional medical therapies for osteoarthritis are mainly palliative in nature, aiming to control pain and symptoms. Traditional intra-articular therapies are not recommended in guidelines as first line therapy, but are potential alternatives, when conventional therapies have failed.

AREAS COVERED

Current and future intra-articular drug therapies for osteoarthritis are highlighted, including corticosteroids, hyaluronate, and more controversial treatments marketed commercially, namely platelet rich plasma and mesenchymal cell therapy. Intraarticular disease modifying osteoarthritis drugs are the future of osteoarthritis treatments, aiming at structural modification and altering the disease progression. Interleukin-1β inhibitor, bone morphogenic protein-7, fibroblast growth factor 18, bradykinin B2 receptor antagonist, human serum albumin, and gene therapy are discussed in this review. The evolution of drug development in osteoarthritis is limited by the ability to demonstrate effect. High quality trials are required to justify the use of existing intra-articular therapies and to advocate for newer, promising therapies.

EXPERT OPINION

Challenges in osteoarthritis therapy research are fundamentally related to the complexity of the pathological mechanisms of osteoarthritis. Novel drugs offer hope in a disease with limited medical therapy options. Whether these future intra-articular therapies will provide clinically meaningful benefits, remains unknown.

Weekly injections of Hylan G-F 20 delay cartilage degeneration in partial meniscectomized rat knees

Background

Cross-linked hyaluronan—also called Hylan G-F 20—is a medical device developed to treat osteoarthritis of the knee. However, it is still controversial whether Hylan G-F 20 has a cartilage protective effect in trauma-induced osteoarthritis. We investigated whether Hylan G-F 20 delayed osteoarthritis progression in a partial meniscectomized rat model.

Methods

Lewis rats were used for the experiments. The anterior medial meniscus was resected at the level of the medial collateral ligament in both knees. From 1 week after the surgery, 50 μl of Hylan G-F 20 was injected weekly into the left knee and phosphate buffered saline was injected into the right knee. Cartilage was evaluated for macroscopic findings, histology with safranin-o, and expression of type II collagen at 2, 4, and 8 weeks. Synovitis was also evaluated, and immunohistochemical analysis was performed for ED1.

Results

Macroscopic findings demonstrated that India ink positive area, representing fibrillated cartilage, was significantly smaller in the Hylan G-F 20 group than in the control group at 2, 4, and 8 weeks (n = 5). There were no significant differences in osteophyte score between the Hylan G-F 20 group and the control group at 2, 4, and 8 weeks.

Histologically, the cartilage in the medial tibial plateau was destroyed at 8 weeks in the control group, while type II collagen expression was still observed at 8 weeks in the Hylan G-F 20 group. OARSI score for cartilage histology was significantly lower in the Hylan G-F 20 group than in the control group at 4 and 8 weeks (n = 5). There were no significant differences in synovial cell number or modified synovitis score between the Hylan G-F 20 group and the control group at 2, 4, and 8 weeks (n = 5). In the Hylan G-F 20 group, foreign bodies surrounded by ED1 positive macrophages were observed in the synovium.

Conclusion

Weekly injections of Hylan G-F 20 starting 1 week after surgery delayed cartilage degeneration after meniscectomy in a rat model. Synovitis induced by meniscectomy was not alleviated by Hylan G-F 20. Insoluble gels were observed in the synovium after the Hylan G-F 20 injection.

Intra-Articular Injection of Cross-Linked Hyaluronic Acid-Dexamethasone Hydrogel Attenuates Osteoarthritis: An Experimental Study in a Rat Model of Osteoarthritis

Cross-linked hyaluronic acid hydrogel (cHA gel) and dexamethasone (Dex) have been used to treat knee osteoarthritis (OA) in clinical practice owing to their chondroprotective and anti-inflammatory effects, respectively. The aim of the present study was to compare the treatment effects of the cHA gel pre-mixed with/without Dex in a surgery-induced osteoarthritis model in rats. Anterior cruciate ligament transection (ACLT) surgery was performed on the right knee of rats to induce OA. Male 2-month-old Sprague-Dawley rats were randomly divided into five groups (n = 10/per group): (1) ACLT + saline; (2) ACLT + cHA gel; (3) ACLT + cHA-Dex (0.2 mg/mL) gel; (4) ACLT + cHA-Dex (0.5 mg/mL) gel; (5) Sham + saline. Intra-joint injections were performed four weeks after ACLT in the right knee. All animals were euthanized at 12 weeks post-surgery. Cartilage damage and changes in the synovial membrane were assessed by micro X-ray, Indian ink articular surface staining, Safranin-O/Fast Green staining, immunohistochemistry, hematoxylin and eosin staining of the synovial membrane, and quantitative reverse transcription-polymerase chain reaction for changes in gene expression. Micro X-ray revealed that the knee joint treated with the cHA-Dex gel was wider than those treated with cHA gel alone or saline. The cHA-Dex gel group had less Indian ink staining (indicator of cartilage fibrillation) than the cHA gel or saline injection groups. Safranin-O/Fast Green staining indicated that increased proteoglycan staining and less cartilage damage were found in the cHA-Dex gel group compared with the cHA gel or saline injection groups. Quantification of histology findings from saline, cHA gel, cHA-Dex (0.2 mg/mL) gel, cHA-Dex (0.5 mg/mL) gel, and sham groups were 5.84 ± 0.29, 4.50 ± 0.87, 3.00 ± 1.00, 2.00 ± 0.48, and 0.30 ± 0.58 (p < 0.05), respectively. A strong staining of type II collagen was found in both the cHA-Dex gel groups compared with saline group or cHA alone group. Similar result was found for the mRNA level of aggrecan and opposite result for type X collagen. Hematoxylin and eosin staining in the synovial membrane showed less synovial lining cell layers and reduced inflammatory cell infiltration in cHA-Dex gel-treated animals compared with saline or cHA only groups. Altogether, cHA-Dex gel has better chondroprotective and anti-inflammatory effects in rat surgery-induced osteoarthritis than cHA alone.

Characterization of viscosupplementation formulations using chemical exchange saturation transfer (ViscoCEST)

Background

Osteoarthritis (OA) is characterized by progressive loss of cartilage in joints, and is a major cause of pain and disability, and imposes significant health care expense. New therapies are being developed to treat the symptomatic effect of OA, one of which is intra-articular injection of viscosupplementations of different forms of hyaluronic acid (HA). The current study evaluates the chemical exchange saturation transfer (CEST) effect from two popular viscosupplementations [Hylan gf-20 (Synvisc) and hyaluronan (Orthovisc)] by targeting the exchangeable hydroxyl protons present on these molecules (ViscoCEST).

Methods

ViscoCEST imaging from two viscosupplementations (Synvisc and Orthovisc) was performed on a 7T Siemens whole body MRI scanner. ViscoCEST images were collected with different combination of saturation pulse power and saturation duration. Z spectra were acquired at B_1rms of 3.6 μT and 1 s saturation duration by varying the frequency from −4 to +4 ppm in step size of 0.1 ppm. Field inhomogeneity (B₀) and radiofrequency (B₁) maps were also acquired to correct ViscoCEST contrast map for any inhomogeneity.

Results

Both viscosupplementations showed broad CEST effect (ViscoCEST), which peaked ~0.8 ppm from down field of water resonance. Orthovisc showed 20 % higher ViscoCEST contrast than Synvisc suggestive of more HA component in Orthovisc. Increased ViscoCEST contrast was observed from both viscosupplementations with increase in B_1rms and saturation pulse duration.

Conclusion

ViscoCEST has a potential to image the spatial distribution of viscosupplements in vivo in patients’ intra-articular space as well as temporal variation in their spatial distribution.

Steroids, lidocain and ioxaglic acid modify the viscosity of hyaluronic acid: in vitro study and clinical implications

Background

Viscosupplementaion by intra-articular injection of hyaluronic acid (HA) is a therapeutic modality for treating osteoarthritis of the knee, of the hip and less frequently of other joints. During viscosupplementation, it is usual to inject other drugs, without knowing whether this association may have a deleterious effect thereon. The rheological properties of a viscosupplement are highly dependent on the product [molecular weight × concentration] of HA. Therefore, any reduction of its viscoelastic properties is related either to a decrease of its concentration or/and of its molecular weight. The presence of other molecules can create favorable or unfavorable molecular interactions with HA. The objective of the study was to investigate the effect of products, that are commonly associated with HA (corticosteroids, lidocain, iodinated contrast media), on the rheological behavior of HA, then to try drawing practical conclusions.

Methods

The rheological behavior of both a linear and a cross-linked HA, was studied before and after mixing with different volumes (ratio 1:0.5–1:4) of the following compounds: phosphate buffered saline (PBS, as a control), cortivazol, triamcinolone hexacetonide, lidocain chlorhydrate and meglumine ioxaglate. The flow curve of the different samples was obtained using a measuring method based on a constant shear rate.

Results

Whatever the dilution and the added molecule were, viscosity of the cross-linked viscosupplement remained much higher than that of the linear one. Addition of PBS at a ratio 1:1 caused a dramatic decrease (up to 97.5 %) of HA viscosity. Cortivazol and lidocain had a similar effect than PBS on linear HA. Both were much deleterious on cross-linked HA viscosity. Among corticosteroids, triamcinolone decreased much less HA viscosity than cortivazol. The effect of meglumine ioxaglate was dose-dependent. Up to a ratio 1:1 viscosity of the linear HA remained above the dilution effect. On the cross-linked HA, the deleterious effect of the contrast agent was evident as soon as a ratio 1:1 and became very marked at 1:2.

Conclusion

HA viscosity varies widely in presence of other molecules. These changes are due to both dilution and molecular interactions. This study suggests that addition of other molecules with HA can lead to a major decrease of its viscosity. However, provided to respect a maximum ratio of 1:1, the contrast medium and triamcinolone seem to have no major deleterious effect on the viscosity level, especially on crosslinked HA. The study also suggests a deleterious effect of lidocain on the cross-linked HA. These in vitro data suggest that drugs associations must be avoided when they are not essential. However, clinical trials are needed to determine whether these rheological changes may have a significant impact on the clinical outcome.

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.

Experimentally induced cartilage degeneration treated by pulsed electromagnetic field stimulation; an in vitro study on bovine cartilage

BACKGROUND

Osteoarthritis (OA) is the final result of progressive alterations to articular cartilage structure, composition and cellularity, followed by an increase in the concentration of pro-inflammatory cytokines in joint synovial fluid. Even though the effect of pulsed electromagnetic field (PEMF) stimulation in counteracting OA progression and inflammation is of increasing interest, because of its anabolic and anti-inflammatory properties, the present study aimed to improve the knowledge on cartilage extracellular matrix (ECM) and chondrocyte changes related to the exposure of PEMF, from a histological and histomorphometric point of view.

METHODS

An in vitro OA model was realized, culturing bovine cartilage explants with a high dose of interleukin 1β (IL1β, 50 ng/ml) at different experimental times (24 h, and 7 and 21 days). The effects of PEMFs (75 Hz, 1.5 mT) were evaluated in cartilage explants treated with IL1β or not (control), in terms of cartilage structure, cellularity and proteoglycans, glycosaminoglycans, collagen II and transforming growth factor β1 synthesis by using histology, histomorphometry and immunohistochemistry.

RESULTS

Making a comparison with control cartilage, IL1β-treated explants showed a decrease in cartilage matrix, structure and cellularity parameters. PEMFs were able to counteract the progression of OA acting on both cartilage cellularity and ECM in cartilage previously treated with IL1β. Normal distribution (Kolmogroc-Smirnov test) and homoscedasticity (Levene test) of data were verified, then, the non-parametric Kruskal Wallis test followed by Mann-Whiteny U test for pairwise comparisons were performed. The p-value was adjusted according to the Dunn-Sidak correction.

CONCLUSIONS

These results, obtained by culturing and treating cartilage explants from two different joints, confirmed that PEMF stimulation can be used as adjuvant therapy to preserve cartilage from detrimental effects of high inflammatory cytokine levels during OA.

Pain relief and improved physical function in knee osteoarthritis patients receiving ongoing hylan G-F 20, a high-molecular-weight hyaluronan, versus other treatment options: data from a large real-world longitudinal cohort in Canada

From the Southwestern Ontario database, one of the largest primary-care datasets in Canada, 1,263 patients with osteoarthritis (OA) of one or both knees were identified who received two consecutive series of intra-articular (IA) injections of hylan G-F 20 preparation and no other prescribed OA medications, and were evaluated fully between 2006 and 2012. A cohort of 3,318 demographically matched OA patients who had not been treated with IA injection therapy was identified from the same database for comparison. Responses to therapy were assessed by means of a 10-point visual analog scale (VAS) for pain at rest and after completion of a 6-minute walk test (6MWT), while physical capacity was measured by performance in the 6MWT itself. After two cycles of hylan G-F 20 therapy, the average VAS score for pain at rest declined from 7.82±1.27 at baseline to 4.16±1.51 (average change 3.66±1.78, significantly more than the reduction of 3.12±2.03 seen in the reference group [P<0.012]) and the average VAS score for pain after the 6MWT decreased by 5.56±1.74 points (from 9.58±0.4 at baseline to 4.02±1.67 at the final assessment), a significantly larger change than that seen in the reference group (Δ2.99±1.85; P<0.001 for intergroup comparison). Distance walked in the 6MWT increased on average by 115 m, significantly more than that seen in the reference group (Δ91 m; P<0.001 for intergroup comparison). These findings from a primary-care database suggest sustained benefits in terms of pain and physical function from repeat cycles of IA injections of hylan G-F 20 and no other prescribed OA medications in adults with OA of the knee.

[Injection treatment with hyaluronic acid]

This article presents the spectrum of indications for the use of hyaluronic acid (HA) based on the recommendations of the European League Against Rheumatism (EULAR), the American College of Rheumatology (ACR), the Osteoarthritis Research Society International (OARSI), the International Institute for Health and Clinical Excellence (NICE) and the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO) taking the reality of patient care in Europe into account.

Hylan G-F 20 attenuates posttraumatic osteoarthritis progression: Association with upregulated expression of the circardian gene NPAS2

AIMS

The study was to examine the effect of Hylan G-F 20 on the progression of posttraumatic osteoarthritis (PTOA) and the expression of the circadian genes neuronal PAS domain protein 2 (NPAS2) and period 2 (Per2).

MAIN METHODS

We used the anterior cruciate ligament transaction and medial menisectomy (ACLT+MMx) model in Wistar rats. The rats were divided into three groups, the sham-operated group, the Hylan G-F 20-treated group, and the saline-treated group. Rats which underwent ACLT + MMx surgery were injected intraarticularly with, respectively, Hylan G-F 20 or saline once a week for 3 consecutive weeks, starting 7days after surgery. The gross morphology and histopathology of the experimental knee joints were evaluated at the end of week 6. Expression of the NPAS2 and Per2 genes was measured by real-time PCR.

KEY FINDINGS

Hylan G-F 20 suppressed the articular cartilage destruction and synovitis compared to the saline-treated group. Compared to the sham-operated group, the Hylan G-F 20-treated group showed significantly upregulated expression of NPAS2 in cartilage (2.53±0.08-fold higher; p<0.05) and a non-significant increase in Per2 expression (2.35±1.26-fold higher p=0.28), while the saline-treated group showed significant downregulation of NPAS2 expression and a non-significant decrease in Per2 expression.

SIGNIFICANCE

Our data suggested that early intraarticular injection of Hylan G-F 20 attenuates the progression of PTOA and significantly upregulates NPAS2 expression. These findings provide a new direction for studying associations between the use of a pharmacological agent, the degenerative process, and circadian gene expression.

Effects of high molecular weight hyaluronic acid on induced arthritis of the temporomandibular joint in rats

High molecular weight hyaluronic acid (HMWHA) has been used to treat temporomandibular joint (TMJ) disorders, but controversial results have been described. This study aimed to characterize the morphological and biochemical actions of HMWHA on induced arthritis of the TMJ. Twenty-four male Wistar rats were used, and arthritis of the TMJ was induced through an intra-articular injection of Complete Freund's Adjuvant (CFA) (50 μl). One week after arthritis induction, the animals were treated with HMWHA (once per week for three weeks). Histological analyses were performed using sections stained with hematoxylin-eosin, toluidine blue and Picrosirius. Were also performed histomorphometric analysis and birefringence of collagenous fibers (polarization microscopy). Biochemical analyses of TMJ tissues were carried out through measurements of sulfated glycosaminoglycans and zymography for evaluation of metalloproteinase-2 and -9 (MMP-2 and -9). Data were analyzed using paired t-test and unpaired t-test, with a 5% significance level. HMWHA reduced histologic changes and thickness of the articular disc, led to a greater arrangement of collagenous fibers, lower concentration of sulfated glycosaminoglycans and lower activity in all isoforms of MMP-2 and -9 in TMJs with induced arthritis. These findings suggest that HMWHA may exert a protective effect on the TMJ.

Consensus statement on viscosupplementation with hyaluronic acid for the management of osteoarthritis

Viscosupplementation (VS) with hyaluronic acid is currently used by physicians to treat osteoarthritis. However, many aspects of this treatment remain questionable and subject of controversy. A group of 8 experts in this field, from European countries, met to debate on 24 statements previously listed by the group members. Based on an extensive research of the literature and expert opinion, a consensus position has been proposed for each statement. Agreement was achieved on some recommendations. In particular, the expert achieved unanimous agreement in favor of the following statements: VS is an effective treatment for mild to moderate knee OA; VS is not an alternative to surgery in advanced hip OA; VS is a well-tolerated treatment of knee and other joints OA; VS should not be used only in patients who have failed to respond adequately to analgesics and NSAIDs; VS is a "positive" indication but not a "lack of anything better" indication; the dosing regimen must be supported by evidence-based medicine; cross-linking is a proven means for prolonging IA residence time of HA; the best approach to inject accurately knee joint is the lateral mid-patellar one; when VS is performed under fluoroscopy, the amount of radiopaque contrast agent must be as low as possible to avoid viscosupplement dilution. These clear recommendations have been established to help practitioners in the use of viscosupplementation.

Strategies for controlled delivery of biologics for cartilage repair

The delivery of biologics is an important component in the treatment of osteoarthritis and the functional restoration of articular cartilage. Numerous factors have been implicated in the cartilage repair process, but the uncontrolled delivery of these factors may not only reduce their full reparative potential but can also cause unwanted morphological effects. It is therefore imperative to consider the type of biologic to be delivered, the method of delivery, and the temporal as well as spatial presentation of the biologic to achieve the desired effect in cartilage repair. Additionally, the delivery of a single factor may not be sufficient in guiding neo-tissue formation, motivating recent research toward the delivery of multiple factors. This review will discuss the roles of various biologics involved in cartilage repair and the different methods of delivery for appropriate healing responses. A number of spatiotemporal strategies will then be emphasized for the controlled delivery of single and multiple bioactive factors in both in vitro and in vivo cartilage tissue engineering applications.

Overexpression of cystatin C in synovium does not reduce synovitis or cartilage degradation in established osteoarthritis

Introduction

Cathepsin K (catK) expression is increased in cartilage, bone and synovium during osteoarthritis (OA). To study the role of catK expression and elevated cathepsin activity in the synovium on cartilage destruction in established OA, we overexpressed cystatin C (cysC), a natural cysteine protease inhibitor, in the synovium of rabbit OA joints.

Methods

The ability of cysC to inhibit activity of cathepsins in rabbit OA synovium lysates was tested in vitro using protease activity assay. In vivo, the tissue localization of recombinant adeno-associated virus (rAAV) with LacZ gene after intra-articular injection was determined by β-galactosidase staining of rabbit joints 4 weeks later. To inhibit cathepsin activity in the synovium, a rAAV2-encoding cysC was delivered intra-articularly into rabbit joints 4 weeks after OA was induced by anterior cruciate ligament transection (ACLT). Seven weeks postinjection, endogenous catK and cysC levels as well as the vector-derived cysC expression in the synovium of normal and OA joints were examined by RNA quantification. Synovial cathepsin activity and catK, catB and catL protein levels were determined by activity and Western blot analyses, respectively. Synovitis and cartilage degradation were evaluated by histopathological scoring.

Results

In vitro, the ability of cysC to efficiently inhibit activity of purified catK and OA-induced cathepsins in rabbit synovial lysates was demonstrated. In vivo, the intra-articular delivery of rAAV2/LacZ showed transduction of mostly synovium. Induction of OA in rabbit joints resulted in fourfold increase in catK mRNA compared to sham controls while no change was detected in endogenous cysC mRNA levels in the synovium. Protein levels for catK, catB and catL were also increased in the synovium with a concomitant fourfold increase in cathepsin activity. Joints treated with rAAV2/cysC showed both detection of vector genomes and vector-derived cysC transcripts in the synovium. Production of functional cysC by the vector was demonstrated by complete block of cathepsin activity in the synovium. However, this did not decrease synovitis, bone sclerosis or progression of cartilage degradation.

Conclusions

Increased production of natural cathepsin inhibitor, cysC, in OA synovium does not alleviate synovitis or cartilage pathology during a preexisting OA.

High molecular weight hyaluronic acid increases the differentiation potential of the murine chondrocytic ATDC5 cell line

Osteoarthritis (OA) is a group of common, chronic, and painful inflammatory joint diseases. One important finding in OA patients is a remarkable decrease in the molecular weight of hyaluronic acid (HA) in the synovial fluid of affected joints. Therapeutic HA is available to patients in most parts of the world as a viscosupplementation product for the treatment of OA. Previous clinical reports show that high molecular weight HA (HMWHA) more effectively relieves pain than low molecular weight HA (LMWHA). However, the mechanism behind this finding remains unclear. In this study, we investigated whether a LMWHA (Low-0.9 MDa) and two types of HMWHA (High-1.9 MDa and 6 MDa) differentially affected chondroregulatory action. We tested this using ATDC5 cell, a murine chondrocytic cell line widely used in culture systems to study chondrogenic differentiation. We found that HMWHA, especially hylan G-F 20 (High-6 MDa), significantly induced aggrecan and proteoglycan accumulation, nodule formation, and mRNA expression of chondrogenic differentiation markers in a time- and dose-dependent manner. In addition, we showed that HMWHA prevented TNF-α induced inhibition of chondrogenic differentiation, with no effect on cell proliferation or viability. These results reveal that HMWHA significantly promotes chondrogenic differentiation of ATDC5 cells in vitro, and suggest that HMWHA plays a significant chondroregulatory role in vivo.

Osteoarthritic changes after superior and inferior joint space injection of hyaluronic acid for the treatment of temporomandibular joint osteoarthritis with anterior disc displacement without reduction: a cone-beam computed tomographic evaluation

PURPOSE

This study compared the effect of superior and inferior joint space injections of hyaluronic acid (HA) and evaluated osteoarthritic changes in patients diagnosed with temporomandibular joint (TMJ) anterior disc displacement without reduction (ADDw/oR) in association with osteoarthritis (OA) by cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

One hundred forty-one patients with research diagnostic criteria for ADDw/oR in association with TMJ OA were randomly assigned to 1 of 2 study groups that received superior or inferior joint space injection of HA. CBCT and clinical examination were performed before treatment and at 3 and 9 months after treatment.

RESULTS

One hundred twenty-six patients returned for the 3-month evaluations, and 74 returned for the 9-month evaluations. Condylar remodeling and TMJ function showed improvement in most patients after treatment. At 3 months, remodeling scores in the superior and inferior groups were 2.14 ± 3.16 and 4.08 ± 3.82, respectively, and scores were 4.80 ± 3.36 and 7.47 ± 3.90 at 9 months. There were significant differences between the superior and inferior groups at 3 and 9 months after treatment (3-month, P = .002; 9-month, P = .002). The Helkimo index of the inferior group was significantly lower than that of superior group at 3 and 9 months (3-month, P = .008; 9-month, P = .028). There were no significant differences in maximal mouth opening between the 2 groups at 3 and 9 months (3-month, P = .82; 9-month, P = .20).

CONCLUSION

Superior and inferior joint space injections of HA are effective methods for the treatment of ADDw/oR in association with TMJ OA. The injection of HA within the inferior joint space appears to result in better condylar reparative remodeling and improvement in jaw function.

Secretion of inflammatory factors from chondrocytes by layilin signaling

Layilin (LAYN) is thought to be involved in reorganization of cytoskeleton structures, interacting with merlin, radixin, and talin. Also, LAYN is known to be one of the receptors for hyaluronic acid (HA). In rheumatoid arthritis (RA), inflammatory cytokines like tumor necrosis factor α (TNF-α) have been known to play pathological roles. HA with low molecular weight is speculated to exacerbate inflammation in RA. In this context, differences of quantity and functions of HA receptors would affect the severity of inflammation in RA. Chondrocytes, which play critical roles in maintaining articular cartilage and are affected in RA, express at least kinds of HA receptors like CD44 and LAYN. However, roles and regulation of LAYN in articular chondrocytes have been poorly understood. To clarify regulation of LAYN in chondrocytes, we here investigated whether TNF-α affected expression levels of LAYN in human articular chondrocytes. Next, to clarify LAYN-specific roles in chondrocytes, we investigated whether binding of antibodies to the extracellular domain of LAYN affected secretion of inflammatory cytokines using a chondrosarcoma cell line. As a result, we found that TNF-α up-regulated expression levels of LAYN in the chondrocytes. Further, the LAYN signaling was found to enhance secretion of inflammatory factors, IL-8 and complement5 (C5)/C5a, from the cells. Our results indicate that LAYN would be involved in the enhancement of inflammation and degradation of cartilage in joint diseases such as RA and OA.

Mannitol Preserves the Viscoelastic Properties of Hyaluronic Acid in an In Vitro Model of Oxidative Stress

Introduction

Viscosupplementation by intra-articular injection of hyaluronic acid (HA) is a widely used treatment for lower limb osteoarthritis. However, the injected HA is rapidly degraded by reactive oxygen species (ROS), limiting its time of intra-articular residence. Optimizing clinical effectiveness of viscosupplementation by reducing HA degradation in situ, and therefore increasing the time of contact with the diseased tissue, is a challenging research approach. Mannitol, a powerful ROS scavenger, is a good candidate for this. The aim of this study was to compare in vitro the resistance to ROS-mediated degradation of two marketed viscosupplements (one linear and one cross-linked) to that of two novel viscosupplements combining HA and mannitol.

Methods

A HA viscosupplement at a concentration of 10 g/L (HA 1%), was compared to a HANOX-M, a novel viscosupplement made of a mixture of HA and mannitol. In a second experiment, Hylan G-F 20, a partially cross-linked viscosupplement, was compared to a HANOX-M-XL, a novel cross-linked viscosupplement made of a HA and mannitol (35 g/L). The four HA viscosupplements were subjected to oxidative stress generated by the addition of hydrogen peroxide (H₂O₂) and their rheological behavior (elastic moduli [G′], viscous moduli [G″], and complex viscosity [|η*|]) were compared before and after the oxidative stress exposure.

Results

The two viscosupplements not containing mannitol HA were rapidly degraded by H₂O₂, as demonstrated by the dramatic decrease of |η*|. On the other hand, the rheological properties of HA containing mannitol were not substantially modified in the presence of H₂O₂.

Conclusion

This in vitro study demonstrates that mixing mannitol with HA protects the viscosupplement from ROS-mediated degradation and might therefore increase its intra-articular residence time without substantially modifying its rheological behavior. This in vitro study has to be followed by clinical trials designed to assess whether the addition of mannitol to HA might improve the efficiency and/or the duration of action of viscosupplementation.

Electronic supplementary material

The online version of this article (doi:10.1007/s40744-014-0001-8) contains supplementary material, which is available to authorized users.

A randomized double-blind clinical trial on the treatment of knee osteoarthritis: the efficacy of polynucleotides compared to standard hyaluronian viscosupplementation

BACKGROUND

This randomized, double-blind, parallel-group clinical trial aims to assess the equivalence of intra-articular polynucleotides compared to standard hyaluronic acid (HA) viscosupplementation in the treatment of knee osteoarthritis (OA).

METHODS

75 patients affected by knee OA were assessed for eligibility and 72 were enrolled and randomized to receive either intra-articular polynucleotides (Condrotide-36 patients) or hyaluronic acid (Hyalubrix-36 patients) at the Orthopedic Institute "Gaetano Pini" (Milan). All patients underwent three intra-articular injections of Condrotide or Hyalubrix with an interval of 1week. Participants, care givers, and investigators responsible for outcome assessment were all blinded to group assignment. Primary outcome measurements (KOOS and pain level (1) at rest, (2) at weight-bearing and (3) during physical activity) were evaluated at baseline (T0) and after one (T1), two (T2), six (T6), ten (T10), and 26 (T26)weeks. Secondary measurements included the determination of COMP serum levels at T0, T6 and T26.

RESULTS

The reduction of pain and the increase of KOOS values from baseline were statistically significant for both treatments; nevertheless, for parameter KOOS "symptoms" the treatment with Condrotide showed significant results already after twoweeks (at T2 p=0.003) while the results obtained with Hyalubrix became significant only after 18 weeks (at T18 p=0.01). No significant adverse events were reported.

CONCLUSIONS

Condrotide is as effective as Hyalubrix in reducing knee OA symptoms but showed an earlier response on pain reduction and can therefore be considered a valid alternative to the use of HA in the treatment of OA, avoiding the adverse events of NSAIDs and of intra-articular corticosteroids.

Chondroprotective effects of high-molecular-weight cross-linked hyaluronic acid in a rabbit knee osteoarthritis model

OBJECTIVES

We hypothesized that high-molecular-weight (MW) cross-linked (CL) hyaluronic acid (HA) improves joint lubrication and has an enhanced chondroprotective effect. We examined the histopathological changes and friction coefficients in osteoarthritic knee joints after injecting high-MW CL HA.

DESIGN

A bilateral anterior cruciate ligament transection (ACLT) model in 20 Japanese white rabbits was used. From week 5 after transection, low-MW HA (0.8 × 10(6) Da; HA80) or high-MW CL HA (6 × 10(6) Da; HA600) was injected weekly into 10 right knee for 3 weeks; normal saline (NS) was injected into the 10 left knee. A sham operation was undertaken to exclude spontaneous osteoarthritis (OA) in five knees. Results were evaluated with macroscopy, histopathology (Kikuchi's score), biomechanical testing, and rheological assessment of the joint fluid viscoelasticity. Statistical analysis was performed using one-way analysis of variance with a 95% confidence interval (CI) (P < 0.05).

RESULTS

The macroscopic findings showed severely damaged cartilage in 30% of the NS group and 20% of the HA80 and HA600 groups and intact cartilage in 100% of the sham group. The histological scores and friction coefficients of the HA600 group were significantly lower than those of the NS group (P = 0.007 and P = 0.002, respectively). Viscoelasticity measurements of the joint fluid showed no significant differences between the three treatment groups.

CONCLUSION

High-MW CL HA exerts potential chondroprotective effects and produces superior friction coefficients. Our results suggest that HA600 delays the progression of OA effectively and improves joint lubrication significantly.

Pulsed electromagnetic field therapy for management of osteoarthritis-related pain, stiffness and physical function: clinical experience in the elderly

BACKGROUND

Pulsed electromagnetic field (PEMF) therapy has shown promising therapeutic effectiveness on bone- and cartilage-related pathologies, being also safe for management of knee osteoarthritis.

AIM

The aim of this study was to investigate the clinical efficacy of a PEMF device for management of knee osteoarthritis in elderly patients.

MATERIALS AND METHODS

A total of 33 patients were screened, and 28 patients, aged between 60 and 83 and affected by bilateral knee osteoarthritis, were enrolled in this study. They received PEMF therapy on the right leg for a total of three 30-minute sessions per week for a period of 6 weeks, while the left leg did not receive any treatment and served as control. An intravenous drip containing ketoprofen, sodium clodronate, glucosamine sulfate, calcitonin, and ascorbic acid, for a total volume of 500 mL, was administered during PEMF therapy. At baseline and 3 months post-PEMF therapy, Visual Analog Scale (VAS) was used to assess knee pain and Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) was used to measure knee pain, stiffness and physical function.

RESULTS

Changes in VAS and WOMAC scores were calculated for both knees as baseline minus post-treatment. A two sample Student's t-test, comparing change in knee-related VAS pain for PEMF-treated leg (49.8 ± 2.03) vs control leg (11 ± 1.1), showed a significant difference in favor of PEMF therapy (P < 0.001). A two sample Student's t-test comparing change in knee-related WOMAC pain, stiffness, and physical function for PEMF-treated leg (8.5 ± 0.4, 3.5 ± 0.2, 38.5 ± 2.08, respectively) vs control leg (2.6 ± 0.2; 1.6 ± 0.1; 4.5 ± 0.5 respectively), also showed a significant difference in favor of PEMF therapy (P < 0.001). No adverse reactions to therapy were observed.

CONCLUSION

The present study shows that PEMF therapy improves pain, stiffness and physical function in elderly patients affected by knee osteoarthritis.

Injectable hyaluronic-acid-doxycycline hydrogel therapy in experimental rabbit osteoarthritis

Background

Osteoarthritis (OA) is a common joint disease that causes disabilities in elderly adults. However, few long-lasting pharmacotherapeutic agents with low side effects have been developed to treat OA. We evaluated the therapeutic effects of intra-articular injections of hydrogels containing hyaluronic acid (HA) and doxycycline (DOX) in a rabbit OA model.

Results

Thirteen week old New Zealand White rabbits undergone a partial meniscectomy and unilateral fibular ligament transection were administered with either normal saline (NT), HA, DOX or HA-DOX hydrogels on day 0, 3, 6, 9 and 12; animals were also examined the pain assessment in every three days. The joint samples were taken at day 14 post-surgery for further histopathological evaluation. The degree of pain was significantly attenuated after day 7 post-treatment with both HA and HA-DOX hydrogels. In macroscopic appearance, HA-DOX hydrogel group showed a smoother cartilage surface, no or minimal signs of ulceration, smaller osteophytes, and less fissure formation in compare to HA or DOX treatment alone. In the areas with slight OA changes, HA-DOX hydrogel group exhibited normal distribution of chondrocytes, indicating the existence of cartilage regeneration. In addition, HA-DOX hydrogels also ameliorated the progression of OA by protecting the injury of articular cartilage layer and restoring the elastoviscosity.

Conclusion

Overall, from both macroscopic and microscopic data of this study indicate the injectable HA-DOX hydrogels presented as a long-lasting pharmacotherapeutic agent to apply for OA therapy.