Hyaluronan inhibits matrix metalloproteinase-13 in human arthritic chondrocytes via CD44 and P38

Low-Intensity Pulsed Ultrasound Affects Chondrocyte Extracellular Matrix Production via an Integrin-Mediated p38 MAPK Signaling Pathway

Although low-intensity pulsed ultrasound (LIPUS) regulates p38 mitogen-activated protein kinase (MAPK) and promotes cartilage repair in osteoarthritis, the role of integrin-mediated p38 MAPK in the effect of LIPUS on extracellular matrix (ECM) production of normal and OA chondrocytes remains unknown. The aim of this study was to investigate whether LIPUS affects ECM production in normal and OA rabbit chondrocytes through an integrin-p38 signaling pathway. A rabbit model of OA was established by anterior cruciate ligament transection, and chondrocytes were isolated from normal or OA cartilage and cultured in vitro. Chondrocytes were treated with LIPUS and then pre-incubated with the integrin inhibitor GRGDSP or the p38 inhibitor SB203580. Expression of type II collagen, MMP-13, integrin β1, p38 and phosphorylated p38 was assessed by Western blot analysis. We found that type II collagen and integrin β1 were upregulated (p < 0.05), whereas MMP-13 was downregulated (p < 0.05) in normal and OA chondrocytes. Furthermore, phosphorylated p38 was upregulated (p < 0.05) in normal chondrocytes, but downregulated (p < 0.05) in OA chondrocytes after LIPUS stimulation. Pre-incubation of chondrocytes with the integrin inhibitor disrupted the effects of LIPUS on normal and OA chondrocytes. Pre-incubation of chrondocytes with the p38 inhibitor reduced the effects of LIPUS on normal chondrocytes, but had no impact on OA chondrocytes. Our findings suggest that the integrin-p38 MAPK signaling pathway plays an important role in LIPUS-mediated ECM production in chondrocytes.

Synergistic anabolic actions of hyaluronic acid and platelet-rich plasma on cartilage regeneration in osteoarthritis therapy

Osteoarthritis (OA) is a common disease associated with tissue inflammation, physical disability and imbalanced homeostasis in cartilage. For advanced treatments, biological approaches are currently focused on tissue regeneration and anti-inflammation. This study was undertaken to evaluate the therapeutic efficacies of hyaluronic acid (HA) and platelet-rich plasma (PRP) (HA+PRP) on OA. Articular chondrocytes were obtained from five OA patients. The optimal HA and PRP concentrations were evaluated by MTT assay. The expressions of chondrogenic and inflammatory genes were analyzed by RT-PCR. Signaling pathway was examined by immunoblotting and the expressions of OA pathology-related chemokines and cytokines was demonstrated by real-time PCR-based SuperArray. The therapeutic efficacies of HA+PRP were then demonstrated in 3D arthritic neo-cartilage and ACLT-OA model. Here we showed that HA+PRP could greatly retrieve pro-inflammatory cytokines-reduced articular chondrocytes proliferation and chondrogenic phenotypes, the mechanism of which involve the sequential activation of specific receptors CD44 and TGF-βRII, downstream mediators Smad2/3 and Erk1/2, and the chondrogenic transcription factor SOX9. The real-time PCR-based SuperArray results also indicated that OA pathology-related chemokines and cytokines could be efficiently suppressed by HA+PRP. Moreover, the cartilaginous ECM could be retrieved from inflammation-induced degradation by HA+PRP in both 2D monolayer and 3D neo-cartilage model. Finally, the intra-articular injection of HA+PRP could strongly rescue the meniscus tear and cartilage breakdown and then decrease OA-related immune cells. The combination of HA+PRP can synergistically promote cartilage regeneration and inhibit OA inflammation. This study might offer an advanced and alternative OA treatment based on detailed regenerative mechanisms.

Pharmacological effects of novel cross-linked hyaluronate, Gel-200, in experimental animal models of osteoarthritis and human cell lines

OBJECTIVE

To study the pharmacological effects of Gel-200, cross-linked hyaluronate.

EXPERIMENTAL DESIGN

We examined the chondroprotective, anti-inflammatory and analgesic effects of Gel-200 in experimental animal models for osteoarthritis (OA) and in a human synovial sarcoma cell line and normal human articular chondrocytes.

RESULTS

In the OA model, a single-dose intra-articular (IA) injection of Gel-200 significantly suppressed cartilage degeneration and reduced synovitis of the knee joint. In the joint pain model, Gel-200 significantly suppressed pain responses for 4 weeks after injection. The residual property of Gel-200 in the knee joint tissue was investigated in rabbits. The mean residual ratio of injected Gel-200 in the synovium was 3.3% (95% confidence interval [CI], 2.4-4.2) at 28 days after the injection. The long-lasting analgesic effect of Gel-200 might be explained by its high residual ratio in the joint. In addition, we investigated the mechanism of action of Gel-200 in a human synovial sarcoma cell line and normal human articular chondrocytes. Gel-200 inhibited IL-1β-induced production of MMP-1, 3 and 13 in human chondrocytes and production of prostaglandin E2 in human synoviocytes in a concentration-dependent manner, respectively.

CONCLUSION

A single-dose IA injection of Gel-200 exerts chondroprotective and anti-inflammatory effects in the experimental OA model, and long-lasting analgesia in the joint pain model, suggesting the beneficial multimodal function of Gel-200 against symptomatic OA patients.

Sorbitol-modified hyaluronic acid reduces oxidative stress, apoptosis and mediators of inflammation and catabolism in human osteoarthritic chondrocytes

OBJECTIVE AND DESIGN

Our study was designed to elucidate the precise molecular mechanisms by which sorbitol-modified hyaluronic acid (HA/sorbitol) exerts beneficial effects in osteoarthritis (OA).

METHODS

Human OA chondrocytes were treated with increasing doses of HA/sorbitol ± anti-CD44 antibody or with sorbitol alone and thereafter with or without interleukin-1beta (IL-1β) or hydrogen peroxide (H2O2). Signal transduction pathways and parameters related to oxidative stress, apoptosis, inflammation, and catabolism were investigated.

RESULTS

HA/sorbitol prevented IL-1β-induced oxidative stress, as measured by reactive oxygen species, p47-NADPH oxidase phosphorylation, 4-hydroxynonenal (HNE) production and HNE-metabolizing glutathione-S-transferase A4-4 expression. Moreover, HA/sorbitol stifled IL-1β-induced metalloproteinase-13, nitric oxide (NO) and prostaglandin E2 release as well as inducible NO synthase expression. Study of the apoptosis process revealed that this gel significantly attenuated cell death, caspase-3 activation and DNA fragmentation elicited by exposure to a cytotoxic H2O2 dose. Examination of signaling pathway components disclosed that HA/sorbitol prevented IL-1β-induced p38 mitogen-activated protein kinase and nuclear factor-kappa B activation, but not that of extracellular signal-regulated kinases 1 and 2. Interestingly, the antioxidant as well as the anti-inflammatory and anti-catabolic effects of HA/sorbitol were attributed to sorbitol and HA, respectively.

CONCLUSIONS

Altogether, our findings support a beneficial effect of HA/sorbitol in OA through the restoration of redox status and reduction of apoptosis, inflammation and catabolism involved in cartilage damage.

Intra-articular hyaluronic acid injection versus oral non-steroidal anti-inflammatory drug for the treatment of knee osteoarthritis: a multi-center, randomized, open-label, non-inferiority trial

Introduction

While many of the commonly used conservative treatments for knee osteoarthritis (OA) have been recognized to be effective, there is still insufficient evidence available. Among the pharmacological treatments for knee OA, oral non-steroidal anti-inflammatory drugs (NSAIDs) act rapidly and are recommended for the management of OA. However, frequent and serious adverse effects of NSAIDs have been recognized. Intra-articular injections of hyaluronic acid (IA-HA) for the treatment of knee OA have been shown to reduce pain and improve joint function. However, there has been no qualified direct comparison study of the efficacy and safety between IA-HA and NSAIDs for patients with knee OA. The aim of this study was to clarify the efficacy and safety of early-phase IA-HA in comparison to those of NSAIDs for patients with knee OA.

Methods

This multicenter, randomized, open-label, parallel-group, non-inferiority comparison study with an oral NSAID involved a total of 200 patients with knee OA. An independent, computer-generated randomization sequence was used to randomly assign patients in a 1:1 ratio to NSAIDs three times per day for five weeks (n = 100) or IA-HA once a week for five weeks (n = 100). The primary endpoint was the percentage change in the patient-oriented outcome measure for knee OA, the Japanese Knee Osteoarthritis Measure (JKOM) score. All patients were questioned regarding any adverse events during treatment. The full analysis set (FAS) was used for analysis. The margin of non-inferiority was 10%.

Results

The analyses of primary endpoint included 98 patients in the IA-HA group and 86 patients in the NSAID group. The difference in the percentage changes of the JKOM score between the two intervention arms (IA-HA; -34.7% (P<0.001), NSAID; -32.2% (P<0.001)) was -2.5% (95% confidence interval (CI): -14.0 to 9.1), indicating IA-HA was not inferior to NSAID. The frequency of both withdrawal and adverse events in the IA-HA group were significantly lower than those in the NSAID group (P = 0.026 and 0.004, respectively).

Conclusions

The early efficacy of IA-HA is suggested to be not inferior to that of NSAIDs, and that the safety of the early phase of IA-HA is superior to that of NSAIDs for patients with knee OA.

Trial registration

UMIN Clinical Trials Registry (UMIN-CTR), UMIN000001026.

The anti-inflammatory and matrix restorative mechanisms of platelet-rich plasma in osteoarthritis

BACKGROUND

Intra-articular (IA) treatment with platelet-rich plasma (PRP) for osteoarthritis (OA) results in improved patient-reported pain and function scores.

PURPOSE

To measure the effects of PRP and high molecular weight hyaluronan (HA) on the expression of anabolic and catabolic genes and on the secretion of nociceptive and inflammatory mediators from OA cartilage and synoviocytes.

STUDY DESIGN

Controlled laboratory study.

METHODS

Synovium and cartilage harvested from patients undergoing total knee arthroplasty were co-cultured with media of PRP or HA. Tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and IL-1β were measured in the media by enzyme-linked immunosorbent assay. Hyaluronan synthase-2 (HAS-2), matrix metalloproteinase-1 (MMP-1), MMP-13, and TNF-α genes were measured in synoviocytes by reverse transcription polymerase chain reaction (RT-PCR). Collagen type I α1 (COL1A1), COL2A1, aggrecan (ACAN), and MMP-13 gene expression were measured in cartilage by quantitative RT-PCR.

RESULTS

Media TNF-α concentration was decreased in PRP and HA compared with control cultures (PRP = 6.94 pg/mL, HA = 6.39 pg/mL, control = 9.70 pg/mL; P ≤ .05). Media IL-6 concentration was decreased in HA compared with PRP and control (HA = 5027 pg/mL, PRP = 5899 pg/mL, control = 5613 pg/mL; P ≤ .05). Media IL-1β was below detectable concentrations (<0.1 pg/mL) in all samples. Synoviocyte MMP-13 expression was decreased in PRP compared with HA and control (PRP = 10.1, HA = 12.8, control = 13.5; P ≤ .05). Synoviocyte HAS-2 expression was increased in PRP compared with HA and control (PRP = 12.1, HA = 9.8, control = 8.7; P ≤ .05). Cartilage ACAN expression was increased in PRP compared with HA, but neither was different from control (PRP = 8.8, HA = 7.7, control = 7.6; P ≤ .05); COL1A1 expression was increased in HA compared with PRP, but neither was different from control (PRP = 14.9, HA = 13.5, control = 12.9; P ≤ .05). Neither platelet nor leukocyte concentration had a significant effect on outcome measurements (gene or protein expression data) in cartilage or synoviocytes (P > .05).

CONCLUSION

Both PRP and HA treatments of OA joint tissues result in decreased catabolism, but PRP treatment also resulted in a significant reduction of MMP-13, an increase in HAS-2 expression in synoviocytes, and an increase in cartilage synthetic activity compared with HA. These results indicate that PRP acts to stimulate endogenous HA production and decrease cartilage catabolism. Platelet-rich plasma showed similar effects as HA in the suppression of inflammatory mediator concentration and expression of their genes in synoviocytes and cartilage.

CLINICAL RELEVANCE

The antinociceptive and anti-inflammatory activities of PRP support its use in OA joints to reduce pain and modulate the disease process. This study supports further clinical investigations of IA PRP for the treatment of OA.

The Application of Polysaccharide Biocomposites to Repair Cartilage Defects

Owing to own nature of articular cartilage, it almost has no self-healing ability once damaged. Despite lots of restore technologies having been raised in the past decades, no repair technology has smoothly substituted for damaged cartilage using regenerated cartilage tissue. The approach of tissue engineering opens a door to successfully repairing articular cartilage defects. For instance, grafting of isolated chondrocytes has huge clinical potential for restoration of cartilage tissue and cure of chondral injury. In this paper, SD rats are used as subjects in the experiments, and they are classified into three groups: natural repair (group A), hyaluronic acid repair (group B), and polysaccharide biocomposites repair (hyaluronic acid hydrogel containing chondrocytes, group C). Through the observation of effects of repairing articular cartilage defects, we concluded that cartilage repair effect of polysaccharide biocomposites was the best at every time point, and then the second best was hyaluronic acid repair; both of them were better than natural repair. Polysaccharide biocomposites have good biodegradability and high histocompatibility and promote chondrocytes survival, reproduction, and spliting. Moreover, polysaccharide biocomposites could not only provide the porous network structure but also carry chondrocytes. Consequently hyaluronic acid-based polysaccharide biocomposites are considered to be an ideal biological material for repairing articular cartilage.

Activated protein C inhibits proliferation and tumor necrosis factor α-stimulated activation of p38, c-Jun NH2-terminal kinase (JNK) and Akt in rheumatoid synovial fibroblasts

Synovial fibroblast proliferation is a hallmark of the invasive pannus in the rheumatoid joint. Activated protein C (APC) is a natural anticoagulant that exerts antiinflammatory and cyto-protective effects in various diseases via endothelial protein C receptor (EPCR) and proteinase-activated receptor (PAR)-mediated pathways. In this study, we investigated the effect and the underlying cellular signaling mechanisms of APC on proliferation of human rheumatoid synovial fibroblasts (RSFs). We found that APC stimulated proliferation of mouse dermal fibroblasts (MDFs) and normal human dermal fibroblasts (HDFs) by up to 60%, but robustly downregulated proliferation of RSFs. APC induced the phosphorylation of extracellular signal-regulated protein kinase (ERK) and enhanced expression of p21 and p27 in a dose-dependent manner in RSFs. The latter effect was inhibited by pre-treatment with the ERK inhibitors PD98059 and U0126 but not by p38 inhibitor SB203580. In addition, APC significantly downregulated tumor necrosis factor (TNF)α-stimulated cell proliferation and activation of p38, c-Jun NH2-terminal kinase (JNK) and Akt in RSFs. These results provide the first evidence that APC selectively inhibits proliferation and the inflammatory signaling pathways of RSFs. Thus, APC may reduce synovial hyperplasia and pannus invasion in rheumatoid arthritis.

Pronounced biomaterial dependency in cartilage regeneration using nonexpanded compared with expanded chondrocytes

Aim: We aimed to investigate freshly isolated compared with culture-expanded chondrocytes with respect to early regenerative response, cytokine production and cartilage formation in response to four commonly used biomaterials. Materials & methods: Chondrocytes were both directly and after expansion to passage 2, incorporated into four biomaterials: Polyactive™, Beriplast®, HyStem® and a type II collagen gel. Early cartilage matrix gene expression, cytokine production and glycosaminoglycan (GAG) and DNA content in response to these biomaterials were evaluated. Results: HyStem induced more GAG production, compared with all other biomaterials (p ≤ 0.001). Nonexpanded cells did not always produce more GAGs than expanded chondrocytes, as this was biomaterial-dependent. Cytokine production and early gene expression were not predictive for final regeneration. Conclusion: For chondrocyte-based cartilage treatments, the biomaterial best supporting cartilage matrix production will depend on the chondrocyte differentiation state and cannot be predicted from early gene expression or cytokine profile.

Hypoxia promotes redifferentiation and suppresses markers of hypertrophy and degeneration in both healthy and osteoarthritic chondrocytes

INTRODUCTION

Hypoxia is considered to be a positive influence on the healthy chondrocyte phenotype and cartilage matrix formation. However, hypoxia-inducible factors (HIFs) have been implicated in the pathogenesis of osteoarthritis (OA). Thus, we assessed whether healthy and OA chondrocytes have distinct responses to oxygen, particularly with regard to hypertrophy and degradation during redifferentiation.

METHODS

Monolayer-expanded healthy and OA chondrocytes were redifferentiated for 14 days in pellet cultures under standard (20% oxygen) or hypoxic (2% oxygen) conditions. Cartilage matrix gene expression, matrix quality and quantity, degradative enzyme expression and HIF expression were measured.

RESULTS

In hypoxia, both healthy and OA chondrocytes had higher human collagen type II, α1 gene (COL2A1), and aggrecan (ACAN) expression and sulfated glycosaminoglycan (sGAG) accumulation, concomitant with lower human collagen type X, α1 gene (COL10A1), and human collagen type I, α1 gene (COL1A1), expression and collagen I extracellular accumulation. OA chondrocytes had significantly lower sGAGs/DNA than healthy chondrocytes, but only in high oxygen conditions. Hypoxia also caused significantly greater sGAG retention and hyaluronic acid synthase 2 (HAS2) expression by OA chondrocytes. Both healthy and OA chondrocytes had significantly lower expression of matrix metalloproteinases (MMPs) MMP1, MMP2, MMP3 and MMP13 in hypoxia and less active MMP2 enzyme, consistent with lower MMP14 expression. However, aggrecanase (ADAMTS4 and ADAMTS5) expression was significantly lowered by hypoxia only in healthy cells, and COL10A1 and MMP13 remained significantly higher in OA chondrocytes than in healthy chondrocytes in hypoxic conditions. HIF-1α and HIF-2α had similar expression profiles in healthy and OA cells, increasing to maximal levels early in hypoxia and decreasing over time.

CONCLUSIONS

Hypoxic culture of human chondrocytes has long been acknowledged to result in increased matrix accumulation, but still little is known of its effects on catabolism. We show herein that the increased expression of matrix proteins, combined with decreased expression of numerous degradative enzymes by hypoxia, minimizes but does not abolish differences between redifferentiated healthy and OA chondrocytes. Hypoxia-induced HIF expression is associated with hypertrophic marker and degradative enzyme downregulation and increased measures of redifferentiation in both healthy and OA chondrocytes. Therefore, though HIFs may be involved in the pathogenesis of OA, conditions that promote HIF expression in vitro promote matrix accumulation and decrease degradation and hypertrophy, even in cells from OA joints.

A hexadecylamide derivative of hyaluronan (HYMOVIS®) has superior beneficial effects on human osteoarthritic chondrocytes and synoviocytes than unmodified hyaluronan

Background

Intra-articular hyaluronan (HA) injection provides symptomatic benefit in the treatment of osteoarthritis (OA). Previously we found superior beneficial effects in a large animal OA model of a hexadecylamide derivative compared with unmodified HA of the same initial molecular weight. The current study sought to define possible molecular mechanisms whereby this enhanced relief of symptoms was occurring.

Methods

Chondrocytes and synovial fibroblasts were isolated from tissues of patients undergoing arthroplasty for knee OA. Monolayer cultures of cells were treated with 0, 0.5, 1.0 or 1.5 mg/mL of unmodified HA (500–730 kDa) or a hexadecylamide derivative of HA of the same initial molecular weight (HYADD4®-G; HYMOVIS®) simultaneously or 1 hour before incubation with interleukin (IL)-1beta (2 ng/mL). Cultures were terminated 15 or 30 minutes later (chondrocytes and synovial fibroblasts, respectively) for quantitation of phosphorylated-(p)-JNK, p-NFkappaB, p-p38, or at 24 hours for quantitation of gene expression (MMP1 &13, ADAMTS4 &5, TIMP1 &3, CD44, COL1A1 &2A1, ACAN, PTGS2, IL6, TNF) and matrix metalloproteinase (MMP)-13 activity.

Results

The hexadecylamide derivative of HA had significantly better amelioration of IL-1beta-induced gene expression of key matrix degrading enzymes (MMP1, MMP13, ADAMTS5), and inflammatory mediators (IL6, PTGS2) by human OA chondrocytes and synovial fibroblasts. Pre-incubation of cells with the derivatized HA for 1 hour prior to IL-1beta exposure significantly augmented the inhibition of MMP1, MMP13, ADAMTS4 and IL6 expression by chondrocytes. The reduction in MMP13 mRNA by the amide derivative of HA was mirrored in reduced MMP-13 protein and enzyme activity in IL-1beta-stimulated chondrocytes. This was associated in part with a greater inhibition of phosphorylation of the cell signalling molecules JNK, p38 and NF-kappaB.

Conclusions

The present studies have demonstrated several potential key mechanisms whereby the intra-articular injection of a hexadecylamide derivative of HA may be acting in joints with OA.

Early decrease of serum biomarkers of type II collagen degradation (Coll2-1) and joint inflammation (Coll2-1 NO₂ ) by hyaluronic acid intra-articular injections in patients with knee osteoarthritis: a research study part of the Biovisco study

To measure the evolution of the serum levels of specific Osteoarthritis (OA) biomarker, Coll2-1 and Coll2-1 NO₂ in knee osteoarthritic patients after viscosupplementation (VS). Fifty-one patients with unilateral symptomatic knee were recruited for this prospective open label study. They received three intra-articular injections of 2 ml of hyaluronic acid (Hylan GF-20) and were followed for 3 months. Walking pain was evaluated and serum samples were taken at each visit. Coll2-1 and Coll2-1 NO₂ were measured in the serum using specific immunoassays. Variations over time of each parameter and predictive factor of response were studied. Forty-five patients were analyzed. The serum concentrations of Coll2-1 and Coll2-1 NO₂ were significantly higher in KL III/IV patients compared to KL I/II patients at baseline and decreased systematically over time after VS. Its effect was ever more pronounced in patients with KL III/IV. The serum concentration of Coll2-1 was significantly lower at baseline in responders than in non-responders. This study suggests a rapid slowdown of type II collagen degradation and joint inflammation after VS with Hylan G-20 and gives additional information for the validation of accurate biomarkers for OA. The serum level of Coll2-1 appeared to be a predictive factor for response to treatment.

Mechanisms involved in suppression of ADAMTS4 expression in synoviocytes by high molecular weight hyaluronic acid

Aggrecan degradation is considered to play a key role in the progression of osteoarthritis (OA). Aggrecanases are members of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) family, and degrade aggrecan in OA cartilage. The aim of this study was to clarify the mechanisms of expression of ADAMTS4 induced by IL-1β in human fibroblast-like synoviocyte (HFLS) cells by high molecular weight hyaluronan (HMW-HA), a therapeutic agent used for OA. Monolayer cultures of HFLS cells were incubated with IL-1β and HMW-HA. In some experiments, cells were pretreated with the CD44 function-blocking monoclonal antibody or inhibitors of signaling pathways prior to addition of IL-1β and HMW-HA. The expressions of ADAMTS4 mRNA and protein were monitored using real-time RT-PCR, Western blotting, and immunofluorescence microscopy. To further determine the role of HMW-HA in IL-1β-induced ADAMTS4 expression, activation of p38 mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK), c-jun NH2-terminal kinase (JNK), Akt, and NF-κB were analyzed by Western blotting. HMW-HA suppressed ADAMTS4 mRNA and protein expressions induced by IL-1β. Pretreatment with the anti-CD44 monoclonal antibody recovered the inhibitory effect of HMW-HA on expression of ADAMTS4 mRNA induced by IL-1β. Western blotting analysis revealed that IL-1β-induced phosphorylation of p38 MAPK and JNK protein were diminished by HMW-HA. Furthermore, inhibition of the p38 MAPK and JNK pathways by chemical inhibitors suppressed ADAMTS4 mRNA expression stimulated by IL-1β. These results suggest that HMW-HA plays an important role as a regulatory factor in synovial tissue inflammation.

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.

Intra-articular injections of hyaluronic acid induce positive clinical effects in knees of patients affected by haemophilic arthropathy

INTRODUCTION

Haemophilic arthropathy is the most common clinical manifestation of haemophilia, secondary to recurrent haemarthrosis and chronic synovitis, and the knee represents the main target joint. Modern bleeding prevention has significatively limited the incidence of severe arthropathy, and primary approach is usually conservative. Viscosupplementation is felt as one of the most efficient treatments for the early stages of knee haemophilic arthropathy, based on short-term follow-up studies. The aim of this prospective case series study is to assess the clinical effectiveness of intra-articular administration of hyaluronic acid in the knee, evaluating long-term results, and focusing on the necessity of further treatments after viscosupplementation.

METHODS

Twenty-seven haemophilic patients with knee arthropathy underwent at least two cycles of injections of hyaluronians between 2003 and 2009. They were evaluated with VAS, SF-36, WFH, Pettersson score, and WOMAC, with a seven-year follow-up.

RESULTS

All patients showed improvement in pain relief and functional recovery without any complications. Considering the severity of arthropathy in haemophilic patients, only a limited number of subjects (five) underwent total knee arthroplasty for persistent pain or functional limitation.

CONCLUSIONS

Viscosupplementation is a safe and effective therapeutic strategy in knee haemophilic arthropathy, with no complications, persisting good clinical results, and determining in most cases a delay of surgery.

Efficacy Evaluation of a New Hyaluronan Derivative HYADD® 4-G to Maintain Cartilage Integrity in a Rabbit Model of Osteoarthritis

Objective: To test the efficacy of a hyaluronan derivative (HYADD^®4-G) in a model of osteoarthritis (anterior cruciate ligament [ACLT]) and to compare its efficacy with the injection of growth factors. Design: In a first experimental set-up, specially selected for treatment scheme with published studies on hyaluronan or growth factor efficacy in osteoarthritis, saline, HYADD^®4-G, rh-BMP-7, and the treatments of rh-BMP-7 or rh-BMP-2 with HYADD^®4-G were injected after ACLT, for five times starting 3 weeks after ACLT. Euthanasia was at day 70. The knees were evaluated by gross morphological observation, x-ray, and histology (Study A). In a second experimental set-up selected to evaluate the efficacy of three viscosupplement injections, starting 4 weeks after ACTL, HYADD^®4-G was compared to saline (Study B). Results: (A) X-ray analysis showed more damage in the saline group than all other treatment groups (2.67 ± 0.61 for saline, 0.83 ± 0.26 for HYADD^®4-G, 1.67 ± 0.82 for HYADD^®4-G with rh-BMP-2, 0.75 ± 0.76 for HYADD^®4-G with rh-BMP-7, and 1.58 ± 0.49 for rh-BMP-7), P < 0.05. In the femoral condyle, the Mankin's score for HYADD^®4-G with rh-BMP-2, HYADD^®4-G with rh-BMP-7, and rh-BMP7 alone was statistically lower compared to saline in the medial part; in the lateral part a significant lower value was observed in the HYADD^®4-G with the rh-BMP-2 group. (B) The Kellgren and Lawrence score and Mankin's score was lower in the HYADD^®4-G group than in the saline group (P < 0.002 and P = 0.0031). Conclusions: These two studies suggest that HYADD^®4-G delayed the cartilage degeneration and that the association of HYADD^®4-G with growth factors is synergistic.

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

OBJECTIVE

To perform a molecular mechanism-based investigation of the chondroprotective potential of hylan G-F 20.

METHOD

The effects of hylan G-F 20 on IL-1β-induced glycosaminoglycan (GAG) depletion and matrix metalloproteinase (MMP) expression in bovine and human cartilage explants were evaluated. Three weekly intra-articular hylan G-F 20 or control injections were administered 4 weeks post-operatively to rabbits with surgically induced osteoarthritis (OA). Cartilage histopathologic scores and osteophyte size were evaluated at 1, 4, and 8 weeks post-injections. Histomorphometry and immunostaining were used to quantify cartilage area and type II collagen (Col II) intensity, and real-time polymerase chain reaction (PCR) was used to examine the mRNA levels of Col2A1, MMP-13, -16 and IL-1β at 1 week.

RESULTS

Hylan G-F 20 retained GAG in IL-1β-exposed bovine and human cartilage explants and abrogated IL-1β-mediated increases in MMP-1, -3, and -13 in human explant culture. Hylan G-F 20‒treated OA joints had significantly better cartilage integrity at 1 and 4 weeks post-treatment and significantly smaller osteophytes at 4 weeks compared with control. Col2A1 mRNA increased with hylan G-F 20 treatment, which correlated with a trend toward increased Col II immunostaining. MMP-13 and -16 mRNAs increased in OA cartilage, but were not significantly altered by hylan G-F 20. IL-1β mRNA was undetectable in cartilage and unaltered in the synovium.

CONCLUSIONS

Hylan G-F 20 improved cartilage integrity and decreased osteophyte formation in the rabbit model of OA. Our results suggest that hylan G-F 20 may stimulate cartilage repair by increasing Col II, and inhibit IL-1β-mediated matrix degradation by decreasing MMPs.

Layilin, a talin-binding hyaluronan receptor, is expressed in human articular chondrocytes and synoviocytes and is down-regulated by interleukin-1β

OBJECTIVE

Layilin (LAYN), a 55-kDa transmembrane protein with homology to C-type lectins, has been identified as a receptor of hyaluronan (HA). Interestingly, LAYN does not share any sequence homology with CD44, a primary HA receptor. The primary aim of our study was to examine the expression and potential function of LAYN in human articular chondrocytes and synoviocytes.

METHODS

Samples were obtained from patients undergoing joint arthroplasty. Cells were grown in vitro, then stimulated with interleukin (IL)-1β or tumor necrosis factor alpha (TNFα) for 24 h and the expression of LAYN was analyzed. To assess the function of LAYN, we transfected chondrocytes with siRNA against LAYN, treated them with HA and IL-1β, and then analyzed the production of matrix metalloproteinase (MMP)-1 and MMP-13 in the treated chrondrocytes.

RESULTS

The results showed that LAYN was constitutively expressed in human articular chondrocytes and synoviocytes and that IL-1β significantly suppressed the expression of LAYN in these cells. HA repressed IL-1β-induced MMP-1 and MMP-13 production in chondrocytes, but this was significantly abrogated in chondrocytes transfected with siRNA against LAYN.

CONCLUSIONS

Our results show that human chondrocytes express LAYN, a novel HA receptor, and that LAYN may contribute to the regulation of HA functions in the arthritic condition. Further investigation of the HA receptor may lead to the development of novel therapeutics to regulate HA signaling in inflammatory arthritis.

Hyaluronan injection in murine osteoarthritis prevents TGFbeta 1-induced synovial neovascularization and fibrosis and maintains articular cartilage integrity by a CD44-dependent mechanism

Introduction

The mechanism by which intra-articular injection of hyaluronan (HA) ameliorates joint pathology is unknown. Animal studies have shown that HA can reduce synovial activation, periarticular fibrosis and cartilage erosion; however, its specific effects on the different cell types involved remain unclear. We have used the TTR (TGFbeta1 injection and Treadmill Running) model of murine osteoarthritis (OA), which exhibits many OA-like changes, including synovial activation, to examine in vivo tissue-specific effects of intra-articular HA.

Methods

The kinetics of clearance of fluorotagged HA from joints was examined with whole-body imaging. Naïve and treated knee joints were examined macroscopically for cartilage erosion, meniscal damage and fibrosis. Quantitative histopathology was done with Safranin O for cartilage and with Hematoxylin & Eosin for synovium. Gene expression in joint tissues for Acan, Col1a1, Col2a1, Col3a1, Col5a1, Col10a1, Adamts5 and Mmp13 was done by quantitative PCR. The abundance and distribution of aggrecan, collagen types I, II, III, V and X, ADAMTS5 and MMP13 were examined by immunohistochemistry.

Results

Injected HA showed a half-life of less than 2 h in the murine knee joint. At the tissue level, HA protected against neovascularization and fibrosis of the meniscus/synovium and maintained articular cartilage integrity in wild-type but not in Cd44 knockout mice. HA injection enhanced the expression of chondrogenic genes and proteins and blocked that of fibrogenic/degradative genes and proteins in cartilage/subchondral bone, whereas it blocked activation of both groups in meniscus/synovium. In all locations it reduced the expression/protein for Mmp13 and blocked Adamts5 expression but not its protein abundance in the synovial lining.

Conclusions

The injection of HA, 24 h after TGFbeta1 injection, inhibited the cascade of OA-like joint changes seen after treadmill use in the TTR model of OA. In terms of mechanism, tissue protection by HA injection was abrogated by Cd44 ablation, suggesting that interaction of the injected HA with CD44 is central to its protective effects on joint tissue remodeling and degeneration in OA progression.

Increased expression of CD44 in hypertrophied ligamentum flavum and relevance of splice variants CD44v5 and CD44v6

BACKGROUND

The most common spinal disorder in the elderly is lumbar spinal stenosis (LSS), which results in part from ligamentum flavum (LF) hypertrophy. Although prior histologic and immunochemical studies have been performed in this area, the pathophysiology of loss of elasticity and hypertrophy is not completely understood. The purpose of this immunohistological study is to elucidate the role of CD44 and its splice variants CD44v5 and CD44v6 in the hypertrophied LF obtained from patients with lumbar spinal stenosis (LSS).

MATERIALS AND METHODS

LF samples of 38 patients with LSS were harvested during spinal decompression. Twelve LF samples obtained from patients with disc herniation and no visible degeneration on preoperative MRI were obtained as controls. Samples were dehydrated and embedded in paraffin. For immunohistochemical determination, slices were stained with antibodies against CD44, Cd44v4, and CD44v6 stained with DAB. LF hypertrophy and cross-sectional area (CSA) were measured with T1-weighted MRI.

RESULTS

CD44 and CD44v5 expression were significantly increased in the hypertrophy group (p < 0.05). CD44v6 expression was not significantly increased. The number of elastic fibers was significantly higher in the hypertrophy group. In the hypertrophy group, LF thickness was significantly increased while CSA was significantly decreased. There was a statistical correlation between LF thickness, CSA, CD44, and CD44v5 expression in the hypertrophy group (p < 0.05).

CONCLUSIONS

LF hypertrophy is accompanied by increased CD44 and CD44v5 expression. CD44v6 expression is not enhanced in LF hypertrophy.

Umbilical cord as a mesenchymal stem cell source for treating joint pathologies

Articular cartilage disorders and injuries often result in life-long chronic pain and compromised quality of life. Regrettably, the regeneration of articular cartilage is a continuing challenge for biomedical research. One of the most promising therapeutic approaches is cell-based tissue engineering, which provides a healthy population of cells to the injured site but requires differentiated chondrocytes from an uninjured site. The use of healthy chondrocytes has been found to have limitations. A promising alternative cell population is mesenchymal stem cells (MSCs), known to possess excellent proliferation potential and proven capability for differentiation into chondrocytes. The “immunosuppressive” property of human MSCs makes them an important candidate for allogeneic cell therapy. The use of allogeneic MSCs to repair large defects may prove to be an alternative to current autologous and allogeneic tissue-grafting procedures. An allogeneic cell-based approach would enable MSCs to be isolated from any donor, expanded and cryopreserved in allogeneic MSC banks, providing a readily available source of progenitors for cell replacement therapy. These possibilities have spawned the current exponential growth in stem cell research in pharmaceutical and biotechnology communities. Our objective in this review is to summarize the knowledge about MSCs from umbilical cord stroma and focus mainly on their applications for joint pathologies.