Hyaluronic acid suppresses fibronectin fragment mediated cartilage chondrolysis: I. In vitro

Apoptosis in the Extraosseous Calcification Process

Extraosseous calcification is a pathologic mineralization process occurring in soft connective tissues (e.g., skin, vessels, tendons, and cartilage). It can take place on a genetic basis or as a consequence of acquired chronic diseases. In this last case, the etiology is multifactorial, including both extra- and intracellular mechanisms, such as the formation of membrane vesicles (e.g., matrix vesicles and apoptotic bodies), mitochondrial alterations, and oxidative stress. This review is an overview of extraosseous calcification mechanisms focusing on the relationships between apoptosis and mineralization in cartilage and vascular tissues, as these are the two tissues mostly affected by a number of age-related diseases having a progressively increased impact in Western Countries.

New Developments in Medical Applications of Hybrid Hydrogels Containing Natural Polymers

New trends in biomedical applications of the hybrid polymeric hydrogels, obtained by combining natural polymers with synthetic ones, have been reviewed. Homopolysaccharides, heteropolysaccharides, as well as polypeptides, proteins and nucleic acids, are presented from the point of view of their ability to form hydrogels with synthetic polymers, the preparation procedures for polymeric organic hybrid hydrogels, general physico-chemical properties and main biomedical applications (i.e., tissue engineering, wound dressing, drug delivery, etc.).

Differences among Branded Hyaluronic Acids in Italy, Part 1: Data from In Vitro and Animal Studies and Instructions for Use

BACKGROUND

The use of hyaluronic acid (HA) for intra-articular (IA) injection is widespread around the world for patients affected by osteoarthritis.

AIM

The aim of this study is to identify scientific evidence from in vitro and in vivo studies supporting the use of IA HAs marketed in Italy. We also evaluated the accuracy of indications and contraindications reported in the leaflets of such HAs compared with the available scientific evidence.

MATERIALS AND METHODS

An extensive literature search was performed to identify all in vitro and in vivo model studies reporting on the effects of various HAs marketed in Italy for IA use. Data reported in the leaflets of different HA-based products for IA use were extracted and analyzed alongside evidence from in vitro and in vivo model studies.

RESULTS

Nine in vitro studies and 11 studies on animal models were examined. Comparing results with what is reported in the leaflets of HAs marketed in Italy, it was observed that many branded formulations are introduced in the market without any reporting of basic scientific evidence. Only 12.82% and 17.95% of branded products had been shown to be effective with scientific evidence from in vitro and in vivo studies, respectively. The rationale of use of these products is based on their nature, as if a class effect existed such that all HAs would yield similar effects.

CONCLUSIONS

Data on HAs deriving from in vitro and in vivo studies are scarce and relate to only a small percentage of products marketed in Italy. Many indications and contraindications are arbitrarily reported in Italian HA leaflets without the support of scientific evidence. Larger and brand-specific studies are necessary and should be reported in the leaflets to guide clinicians in making an appropriate choice regarding HA-based IA therapy.

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.

[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.

Interaction of hyaluronan binding peptides with glycosaminoglycans in poly(ethylene glycol) hydrogels

This study investigates the incorporation of hyaluronan (HA) binding peptides into poly(ethylene glycol) (PEG) hydrogels as a mechanism to bind and retain hyaluronan for applications in tissue engineering. The specificity of the peptide sequence (native RYPISRPRKRC vs non-native RPSRPRIRYKC), the role of basic amino acids, and specificity to hyaluronan over other GAGs in contributing to the peptide-hyaluronan interaction were probed through experiments and simulations. Hydrogels containing the native or non-native peptide retained hyaluronan in a dose-dependent manner. Ionic interactions were the dominating mechanism. In diH2O the peptides interacted strongly with HA and chondroitin sulfate, but in phosphate buffered saline the peptides interacted more strongly with HA. For cartilage tissue engineering, chondrocyte-laden PEG hydrogels containing increasing amounts of HA binding peptide and exogenous HA had increased retention and decreased loss of cell-secreted proteoglycans in and from the hydrogel at 28 days. This new matrix-interactive hydrogel platform holds promise for tissue regeneration.

Hyaluronic acid for the treatment of osteoarthritis in all joints except the knee: what is the current evidence?

BACKGROUND

The use of intra-articular hyaluronic acid (HA) is a well known treatment in patients with knee osteoarthritis (OA). In other joints, less evidence is available about the efficacy of treatment with intra-articular HA. HA is also used intra-articularly in the metatarsophalangeal-1 joint, the ankle, the hip, the sacroiliac joint, the facet joints, the carpometacarpal-1 joint, the shoulder and the temporo-mandibular joint. In this systematic review we include all prospective studies about the effects of intra-articular HA in the above-mentioned joints. Its use in the knee joint, however, will be discussed in a separate article in this journal.

METHODS

A systematic review was conducted using databases including MEDLINE, Cochrane Database of Systematic Reviews, Cochrane Clinical Trial Register, and EMBASE.

RESULTS

After performing a solid systematic review using a rigid methodology and trying to pool the outcomes of different studies, we noticed that, compared with baseline, there is statistical evidence for a positive effect of intra-articular HA. However, there is limited evidence HA is superior to placebo and no evidence that intra-articular HA is better than corticosteroids or other conservative therapies.

CONCLUSION

Our recommendation for future research is that one should focus on adequately powered randomized trials comparing HA treatment with other types of intra-articular or conservative treatment. We think it is useless to further perform and publish (large) non-comparative prospective studies about the use of HA in the treatment of problems caused by OA. It is well perceived that HA exerts positive effects in the treatment of OA, but up to now there is no (strong) evidence available that HA is superior to other treatments of OA such as corticosteroids, physiotherapy or other conservative measures.

Insulin-like growth factor-1 suspended in hyaluronan improves cartilage and subchondral cancellous bone repair in osteoarthritis of temporomandibular joint

This study sought to evaluate the effects of intra-articular injection of insulin-like growth factor-1 (IGF-1) suspended in hyaluronan (HA) on the cartilage and subchondral cancellous bone repair in osteoarthritis (OA) of the temporomandibular joint (TMJ). Disc perforation was performed bilaterally in rabbit TMJs to induce OA. Four groups of animals (n=12) received OA induction only, and either intra-articular HA injection alone, intra-articular IGF-1 injection alone, or a combination of HA and IGF-1 injection. All therapy was begun 4 weeks after OA induction. The animals were killed 12 or 24 weeks after the first injection, for histology and micro-CT examinations. Two additional animals were used as normal controls. Typical cartilage and subchondral cancellous bone lesions were observed in the OA group. No protective effect on cartilage and subchondral cancellous bone was found in the HA or IGF-1 alone groups. Better histological repair and nearly normal micro-architectural properties of the subchondral cancellous bone were observed in the HA+IGF-1 group compared with the HA or IGF-1 alone groups. HA may be used as an effective carrier for intra-articular injection of IGF-1 and the combination of HA/IGF-1 shows promise as a new rational approach to therapy of TMJ OA.

Joint aging and chondrocyte cell death

Articular cartilage extracellular matrix and cell function change with age and are considered to be the most important factors in the development and progression of osteoarthritis. The multifaceted nature of joint disease indicates that the contribution of cell death can be an important factor at early and late stages of osteoarthritis. Therefore, the pharmacologic inhibition of cell death is likely to be clinically valuable at any stage of the disease. In this article, we will discuss the close association between diverse changes in cartilage aging, how altered conditions influence chondrocyte death, and the implications of preventing cell loss to retard osteoarthritis progression and preserve tissue homeostasis.

Effects of mechanical stimuli on the synthesis of superficial zone protein in chondrocytes

Superficial zone protein (SZP) has been demonstrated to contribute to the boundary lubrication in synovial joints. This study was designed to clarify the modulation of SZP expression by mechanical stress in articular chondrocytes. Cyclic tensile strains of 7 and 21% cell elongation were applied to cultured chondrocytes obtained from porcine mandibular condylar cartilage. The mRNA levels of SZP, IL-1 beta, and TGF-beta1 were examined by a quantitative real-time PCR analysis. Protein level of SZP was examined by Western blotting. The SZP mRNA level was significantly upregulated after 12, 24, and 48 h by 7% elongation. Although SZP mRNA level was upregulated by 21% elongation after 12 h, it decreased to a lower level than the control after 48 h. The TGF-beta1 mRNA level exhibited an almost similar change to SZP. The IL-1 beta mRNA level was not changed markedly by 7% elongation. However, the IL-1 beta mRNA level was significantly increased by a 12-h application of 21% elongation. Western blot analysis revealed that the SZP expression was increased by 7% elongation, but decreased remarkably by 21% elongation. It is suggested from these findings that the SZP expression level in the chondrocytes is enhanced by optimal mechanical stimuli, but inhibited by excessive loading partly affected by TGF-beta1 and IL-1 beta, leading to the deterioration of joint lubrication.

Glenohumeral chondrolysis after shoulder arthroscopy associated with continuous bupivacaine infusion

PURPOSE

To determine the incidence of glenohumeral chondrolysis associated with the use of a continuous-infusion device in shoulder arthroscopy.

METHODS

A consecutive series of patients undergoing arthroscopic glenohumeral surgery with a postoperative continuous-infusion pump inserted into either the glenohumeral joint or subacromial space were evaluated for chondrolysis. Two pump types were used: group 1 received 100 mL of 0.5% bupivacaine without epinephrine infused at 2.08 mL/h, and group 2 received 270 mL of 0.5% bupivacaine without epinephrine infused at 4.16 mL/h.

RESULTS

We followed up 65 patients at a mean of 40 months. Of these, 29 had glenohumeral catheters (13 in group 1 and 16 in group 2) and 36 had subacromial catheters (19 in group 1 and 17 in group 2). The overall postoperative Constant, American Shoulder and Elbow Surgeons, Rowe, Single Assessment Numeric Evaluation, and Simple Shoulder Test scores were 84, 87, 77, 86, and 10, respectively, in those with glenohumeral catheters and 93, 94, 95, 89, and 11, respectively, in those with subacromial catheters. Three glenohumeral catheter patients were diagnosed with chondrolysis, all in group 2.

CONCLUSIONS

Chondrolysis developed in 3 of 16 patients (19%) with glenohumeral joint infusion of 0.5% bupivacaine without epinephrine at 4.16 mL/h for 65 hours. No patient using a 2.08-mL/h reservoir for 48 hours into the glenohumeral joint and no patient with a subacromial infusion device had chondrolysis. Clinical symptoms and radiographic evidence of chondrolysis developed before 12 months after surgery.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

[Effect of chondroitin sulfate and hyaluronic acid (500-730 kDa) on synthesis of stromelysin (MMP-3) and MMP-1 in human chondrocyte cultures]

INTRODUCTION

Chondroitin sulfate (CS) and hyaluronic acid (HA) are used in the symptomatic treatment of osteoarthritis (OA). Cholagenase-1 (MMP-1) and stromelysin-1 (MMP-3), are responsible for degradation of the extracellular matrix in OA. Few studies have determined the in vitro effect of CS and HA on MMP-1 synthesis and that of HA on MMP-3 expression in human OA chondrocyte culture. In the literature reviewed, there were no studies evaluating the effect of CS on MMP-3.

OBJECTIVES

To analyze the effect of CS and HA (500-730 kDa) on MMP-3 and MMP-1 synthesis induced by interleukin-1β (IL-1β) in OA chondrocytes.

MATERIAL AND METHODS

Chondrocytes were incubated for 48 hours with IL-1β (2.5 ng/ml) in the presence or absence of different HA concentrations (Hyalgan®, Bioibérica Farma) (10, 50, 100, 150, 200 and 1000 μg/ml). Functional evaluation of chondrocytes was performed by enzyme-immunoanalysis of MMP-1 and MMP-3 levels.

RESULTS

CS and HA inhibited IL-1β-induced MMP-3 synthesis, without significantly modifying MMP-1. CS and HA reduced levels of MMP-3 expression at all the studied concentrations, with no statistically significant differences among these concentrations.

CONCLUSIONS

The results of this study show for the first time that CS inhibits MMP-3 synthesis in OA cartilage. and corroborates the few existing data on the ability of HA to inhibit this enzyme.

Efficacy of Siddha formulation Kalpaamruthaa in ameliorating joint destruction in rheumatoid arthritis in rats

BACKGROUND

Rheumatoid arthritis (RA) is a kind of chronic inflammatory autoimmune disease. The degradation of extracellular matrix and cartilage pave way in understanding the molecular mechanisms in RA. Degradation of cartilage is a more complex event involving the local release of metallaoproteases and lysosomal enzymes that mediate inflammation in joints and in the synovial fluid in RA.

OBJECTIVES

In the present study, the efficacy of a Siddha preparation named Kalpaamruthaa (KA) in ameliorating the disease process via markedly reducing the joint destruction was demonstrated in adjuvant induced arthritis rat model. KA consists of Semecarpus anacardium nut milk extract (SA), dried powder of Emblica officinalis fruit and honey.

MATERIAL AND METHODS

Both SA and KA were administered at dose of 150 mg/kg b.wt. for 14 days after 14 days of adjuvant injection in rats. The activity of lysosomal enzymes, the level of collagen, glycosaminoglycans (GAGs) and its degradative products were analyzed in control and experimental animals.

RESULTS AND CONCLUSION

The study revealed that KA exhibited a profound reduction (p<0.05) in the activities of lysosomal enzymes and thereby decreasing (p<0.05) the levels of GAGs and its fractions when compared to arthritis rats. The latter was confirmed by Safrannin O staining for GAGs in the interphalangeal joints of control and experimental animals. The effect of KA was found to be improved than SA and this might be due to the combined interactions of phytoconstituents present in KA.

Safety and efficacy of intra-articular sodium hyaluronate (Hyalgan) in a randomized, double-blind study for osteoarthritis of the ankle

BACKGROUND

The potential benefit of hyaluronans in alleviating pain associated with osteoarthritis (OA) in joints other than the knee is of increasing interest. This double-blind, randomized, controlled study examined the safety and efficacy of intraarticular sodium hyaluronate (Hyalgan) in the treatment of pain associated with ankle OA.

MATERIALS AND METHODS

Thirty consecutive patients with ankle OA documented by X-ray were randomized to treatment with five weekly injections of either sodium hyaluronate 2 mL (HYL) or phosphate-buffered saline 2 mL (control) in the tibiotalar joint. The primary endpoint was pain on movement and weightbearing using the Ankle Osteoarthritis Scale (AOS) 3 months after injection (a 100-mm visual analog scale [VAS]). Additional measures included the Western Ontario and McMaster Universities (WOMAC) OA Index and patient global assessment through 6 months; the Short Form-12 (SF-12) Health Survey at 3 months and 6 months; and all reported adverse events (AEs).

RESULTS

The study groups differed only in age, baseline WOMAC pain, and AOS total scores; 80% of the HYL and 73% of the control patients completed the study. At Month 3, the primary endpoint of the study, the HYL group demonstrated a significantly greater improvement from baseline in AOS total score than did the control group (HYL: -17.4 +/- 5.0 mm;

CONTROL

-5.1 +/- 4.0 mm; p = 0.0407). The incidence of AEs was low, with no significant differences between the groups. There were no post-injection flares.

CONCLUSION

Our study suggests that sodium hyaluronate may be a safe and effective option for pain associated with ankle OA, although larger studies are needed.

Changes in biochemical markers and prediction of effectiveness of intra-articular hyaluronan in patients with knee osteoarthritis

OBJECTIVE

Intra-articular injection of hyaluronan (HA) is frequently used to treat knee osteoarthritis (OA). We studied whether HA injections induced significant changes in levels of biochemical markers in synovial fluid (SF). In addition, we investigated the possibility of predicting the effectiveness of HA based on these biochemical markers.

METHODS

Twenty-eight patients with knee OA underwent five weekly intra-articular injections of HA. Knee pain was measured on visual analog scale (VAS) before and after the five injections. Levels of biochemical markers, including chondroitin 6-sulfate (C6S), chondroitin 4-sulfate (C4S), keratan sulfate (KS), and tenascin-C (TN-C), were determined before and after the five injections. Correlations between the biochemical markers before HA injection and the improvement of VAS after the five injections were evaluated.

RESULTS

After HA injections, levels of C6S, C4S, and KS decreased significantly. Inverse correlations were observed between the levels of TN-C and C4S before HA injection and improvement of VAS after the five injections. In contrast, no significant correlation was seen between levels of C6S and KS before injections and improvement of VAS after the five injections.

CONCLUSION

The reduction in C6S, C4S, and KS levels after HA injections reflects that HA could help maintain normal cartilage metabolism. Our findings suggest that HA injections are effective in patients whose knees contain low levels of TN-C and C4S, reflecting an early stage of OA and limited synovitis.

Alginate/lactose-modified chitosan hydrogels: a bioactive biomaterial for chondrocyte encapsulation

A new bioactive scaffold was prepared from a binary polysaccharide mixture composed of a polyanion (alginate) and a polycation (a lactose-modified chitosan, chitlac). Its potential use for articular chondrocytes encapsulation and cartilage reconstructive surgery applications has been studied. The hydrogel combines the ability of alginate to act as a 3D supporting structure with the capability of the second component (chitlac) to provide interactions with porcine articular chondrocytes. Physico-chemical characterization of the scaffold was accomplished by gel kinetics and compression measurements and demonstrated that alginate-chitlac mixture (AC-mixture) hydrogels exhibit better mechanical properties when compared with sole alginate hydrogels. Furthermore, biochemical and biological studies showed that these 3D scaffolds are able to maintain chondrocyte phenotype and particularly to significantly stimulate and promote chondrocyte growth and proliferation. In conclusion, the present study can be considered as a first step towards an engineered, biologically active scaffold for chondrocyte in vitro cultivation, expansion, and cell delivery.

Viscosupplementation with hyaluronic acid in hip osteoarthritis (a review)

BACKGROUND

Viscosupplementation (VS) with hyaluronic acid (HA) is largely used for knee osteoarthritis therapy, but the evidences for its usefulness in hip osteoarthritis (OA) are limited.

METHODS

In this review, an extensive search of published trials on VS in hip OA was performed. From the selected papers the following data were extracted: sample size, inclusion/exclusion criteria, treatment procedures, evaluation methods, follow-up duration and clinical outcomes.

RESULTS

The level of evidence was low in quite all the trials (no placebo controlled groups). A reduction of pain and an improvement of function after 3 months, persistent in the long term (12-18 months), was observed. Patients with mild morphological alterations responded better to therapy. Side effects were negligible, and were limited to pain and a sensation of heaviness in the injection site. No clear differences among Low (LMW) and High Molecular Weight (HMW) HA preparations were found in the clinical outcomes. However, for HMW-HA preparations, a lower number of injections was, in general, necessary in order to reach the therapeutic effect.

CONCLUSIONS

Despite the initial promising results, some questions still remain open : 1) the characteristics of responders must be more precisely defined; 2) the treatment schedules, at present mainly based on the individual clinical experience, need a proper and accepted standardization. Finally, larger and placebo controlled trials are necessary to confirm the efficacy of VS in hip OA.

Amelioration of osteoarthritis by intra-articular hyaluronan synthase 2 gene therapy

Osteoarthritis (OA) is a chronic, degenerative disorder of multifactorial aetiology, characterized by loss of articular cartilage and periarticular bone remodelling. Goals of managing OA include controlling pain, maintaining and improving function and health-related quality of life, and limiting functional impairment. Although several managements had been proved to ameliorate the symptoms of osteoarthritis, no methods could cure it thoroughly. High-molecular-weight hyaluronan (HMW-HA) is a major component of synovial joint fluids which physically acts as a viscous lubricant for slow joint movements and as an elastic shock absorber during rapid movements. It also has a variety of biologic effects in vivo, such as inhibiting the release of inflammatory factors and suppressing the degradation of cartilage matrix. Intra-articular injection of synthetic HMW-HA has been used as viscosupplement for knee OA and its therapeutic efficacy has been verified. However, repeated injections of HMW-HA which is needed to control symptoms increase the probability of infection and sometimes there will have acute joint pain with effusion, which requires aspiration to exclude sepsis. In order to overcome the disadvantages of repeated injections of HMW-HA, novel strategies should be developed. As HMW-HA is synthesized by hyaluronan synthase-2 (HAS2), we postulate that HAS2 gene could be delivered into intra-articular cells by methods of gene therapy to achieve long-lasting synthesis of HMW-HA. In our opinion, this strategy seems to hold interesting future prospects for the treatment of OA.

Effects of sodium hyaluronate and methylprednisolone acetate on proteoglycan metabolism in equine articular chondrocytes treated with interleukin-1

OBJECTIVE

To determine the effects of sodium hyaluronate (HA) in combination with methylprednisolone acetate (MPA) on interleukin-1 (IL-1)-induced inflammation in equine articular cartilage pellets.

SAMPLE POPULATION

Chondrocytes collected from 7 horses euthanatized for problems unrelated to the musculoskeletal system.

PROCEDURES

Chondrocyte pellets were treated with medium (negative control); medium containing IL-1 (positive control); or medium containing IL-1 with MPA only (0.05 or 0.5 mg/mL), HA only (0.2 or 2 mg/mL), or MPA (0.05 or 0.5 mg/mL) and HA (0.2 or 2 mg/mL) in combination. Proteoglycan (PG) synthesis was determined by incorporation of sulfur 35-labeled sodium sulfate into PGs. Glycosaminoglycan (GAG) content of the media and the pellets and total pellet DNA content were determined.

RESULTS

Methylprednisolone acetate at 0.5 mg/mL caused an increase in PG synthesis, whereas HA had no effect alone. The combination of MPA, both 0.05 mg/mL and 0.5 mg/mL, with HA at 2 mg/mL increased PG synthesis, compared with IL-1-treated control. All treatment groups containing the high concentration of MPA (0.5 mg/mL) and the high concentration of HA (2.0 mg/mL) had pellets with increased GAG content. The addition of HA caused an increase in total GAG content in the media, regardless of MPA treatment. Cyclooxygenase-2 mRNA and aggrecan mRNA expression was significantly reduced with MPA treatment. Total pellet DNA content was unchanged by any treatment.

CONCLUSIONS AND CLINICAL RELEVANCE

Our results indicate that MPA in combination with HA has beneficial effects on PG metabolism of IL-1-treated equine chondrocytes.

Poly-N-Acetyl Glucosamine-SO4 for Repairing Osteochondral Defect in Rabbits

Repair of osteochondral defects created in rabbit femoral trochlea were studied using a water-soluble sulfated p-GlcNAc formulation, (Marine Polymer Technologies, Danvers, MA, USA). After 12 weeks of healing empty defects were compared to defects filled with sulfated p-GlcNAc sponge alone and sulfated p-GlcNAc sponge seeded with autologous chondrocytes. The chondrocyte seeded sponge provided the best healing of both cartilage and subchondral bone. The sulfated p-GlcNAc sponge alone did not provide as good healing as the chondrocyte seeded sponge, but healing was still superior to that of the empty defect. This study supports the use of p-GlcNAc sponge to augment healing of osteochondral defects in animal models.

The effect of alginate, hyaluronate and hyaluronate derivatives biomaterials on synthesis of non-articular chondrocyte extracellular matrix

Cartilage engineering consists of re-constructing functional cartilage by seeding chondrocytes in suitable biomaterials in vitro. The characteristics of neocartilage differ upon the type of biomaterial chosen. This study aims at determining the appropriate scaffold material for articular cartilage reconstruction using non articular chondrocytes harvested from rat sternum. For this purpose, the use of polysaccharide hydrogels such as alginate (AA) and hyaluronic acid (HA) was investigated. Several ratios of AA/HA were used as well as three derivatives obtained by chemical modification of HA (HA-C18, HA-C12(2.3), HA-C12(2.5)-TEG0.5). Sternal chondrocytes were successfully cultured in 3D alginate and alginate/HA scaffolds. HA retention in alginate beads was found to be higher in beads seeded with cells than in beads without cells. HA-C18 improved HA retention in beads but inhibited the chondrocyte synthesis process. Cell proliferation and metabolism were enhanced in all biomaterials when beads were mechanically agitated. Preliminary results have shown that the chondrocyte neo-synthesised matrix had acquired articular characteristics after 21 days culture.

Chondrocytes, synoviocytes and dermal fibroblasts all express PH-20, a hyaluronidase active at neutral pH

Hyaluronan (HA), an important component of connective tissues, is highly metabolically active, but the mechanisms involved in its catabolism are still largely unknown. We hypothesized that a protein similar to sperm PH-20, the only mammalian hyaluronidase known to be active at neutral pH, could be expressed in connective tissue cells. An mRNA transcript similar to that of PH-20 was found in chondrocytes, synoviocytes, and dermal fibroblasts, and its levels were enhanced upon stimulation with IL-1. In cell layers extracted with Triton X-100 – but not with octylglucoside – and in culture media, a polyclonal antipeptide anti-PH-20 antibody identified protein bands with a molecular weight similar to that of sperm PH-20 (60 to 65 kDa) and exhibiting a hyaluronidase activity at neutral pH. Further, upon stimulation with IL-1, the amounts of the neutral-active hyaluronidase increased in both cell layers and culture media. These findings contribute potential important new insights into the biology of connective tissues. It is likely that PH-20 facilitates cell-receptor-mediated uptake of HA, while overexpression or uncontrolled expression of the enzyme can cause great havoc to connective tissues: not only does HA fragmentation compromise the structural integrity of tissues, but also the HA fragments generated are highly angiogenic and are potent inducers of proinflammatory cytokines. On the other hand, the enzyme activity may account for the progressive depletion of HA seen in osteoarthritis cartilage, a depletion that is believed to play an important role in the apparent irreversibility of this disease process.

Intra-articular injections of high-molecular-weight hyaluronic acid have biphasic effects on joint inflammation and destruction in rat antigen-induced arthritis

To assess the potential use of hyaluronic acid (HA) as adjuvant therapy in rheumatoid arthritis, the anti-inflammatory and chondroprotective effects of HA were analysed in experimental rat antigen-induced arthritis (AIA). Lewis rats with AIA were subjected to short-term (days 1 and 8, n = 10) or long-term (days 1, 8, 15 and 22, n = 10) intra-articular treatment with microbially manufactured, high-molecular-weight HA (molecular weight, 1.7 × 10⁶ Da; 0.5 mg/dose). In both tests, 10 buffer-treated AIA rats served as arthritic controls and six healthy animals served as normal controls. Arthritis was monitored by weekly assessment of joint swelling and histological evaluation in the short-term test (day 8) and in the long-term test (day 29). Safranin O staining was employed to detect proteoglycan loss from the epiphyseal growth plate and the articular cartilage of the arthritic knee joint. Serum levels of IL-6, tumour necrosis factor alpha and glycosaminoglycans were measured by ELISA/kit systems (days 8 and 29). HA treatment did not significantly influence AIA in the short-term test (days 1 and 8) but did suppress early chronic AIA (day 15, P < 0.05); however, HA treatment tended to aggravate chronic AIA in the long-term test (day 29). HA completely prevented proteoglycan loss from the epiphyseal growth plate and articular cartilage on day 8, but induced proteoglycan loss from the epiphyseal growth plate on day 29. Similarly, HA inhibited the histological signs of acute inflammation and cartilage damage in the short-term test, but augmented acute and chronic inflammation as well as cartilage damage in the long-term test. Serum levels of IL-6, tumour necrosis factor alpha, and glycosaminoglycans were not influenced by HA. Local therapeutic effects of HA in AIA are clearly biphasic, with inhibition of inflammation and cartilage damage in the early chronic phase but with promotion of joint swelling, inflammation and cartilage damage in the late chronic phase.

Mechanisms involved in enhancement of osteoclast formation and function by low molecular weight hyaluronic acid

Hyaluronic acid (HA) is a component of the extracellular matrix that has been shown to play an important role in bone formation, resorption, and mineralization both in vivo and in vitro. We examined the effects of HA at several molecular weights on osteoclast formation and function induced by RANKL (receptor activator of NF-kappa B ligand) in a mouse monocyte cell line (RAW 264.7). HA at M(r) < 8,000 (low molecular weight HA (LMW-HA)) enhanced tartrate-resistant acid phosphatase-positive multinucleated cell formation and tartrate-resistant acid phosphatase activity induced by RANKL in a dose-dependent manner, whereas HA at M(r) > 900,000 (high molecular weight HA (HMW-HA)) showed no effect on osteoclast differentiation. LMW-HA enhanced pit formation induced by RAW 264.7 cells, whereas HMW-HA did not, and LMW-HA stimulated the expression of RANK (receptor activator of NF-kappa B) protein in RAW 264.7 cells. In addition, we found that LMW-HA enhanced the levels of c-Src protein and phosphorylation of ERKs and p38 MAPK in RAW 264.7 cells stimulated with RANKL, whereas the p38 MAPK inhibitor SB203580 inhibited RANKL-induced osteoclast differentiation. This enhancement of c-Src and RANK proteins induced by LMW-HA was inhibited by CD44 function-blocking monoclonal antibody. These results indicate that LMW-HA plays an important role in osteoclast differentiation and function through the interaction of RANKL and RANK.

The aggregation of pig articular chondrocyte and synthesis of extracellular matrix by a lactose-modified chitosan

A reductive amination reaction (N-alkylation) obtained exploiting the aldheyde group of lactose and the amino group of the glucosamine residues of chitosan (d.a. 89%) afforded a highly soluble engineered polysaccharide (chitlac) for a potential application in the repair of the articular cartilage. Chitosan derivatives with 9% and 64% of side chain groups introduced have been prepared and characterized by means of potentiometric titration, (1)H-NMR and intrinsic viscosity. Both polymers, with respect to the unmodified chitosan, induce cell aggregation when in contact with a primary culture of pig chondrocytes, leading to the formation of nodules of considerable dimensions (up to 0.5-1 mm in diameter). The nodules obtained from chondrocytes treated with chitlac with the higher degree of substitution have been studied by means of optical and electron microscopy (SEM, TEM) and the production of glycosaminoglycans (GAGs) and collagen has been measured by means of colorimetric assays. The chondro-specificity of GAG and collagen was determined by RT-PCR. The results show that the lactose-modified chitosan is non-toxic and stimulates the production of aggrecan and type II collagen.

Expression analysis of three isoforms of hyaluronan synthase and hyaluronidase in the synovium of knees in osteoarthritis and rheumatoid arthritis by quantitative real-time reverse transcriptase polymerase chain reaction

Hyaluronan is a major molecule in joint fluid and plays a crucial role in joint motion and the maintenance of joint homeostasis. The concentration and average molecular weight of hyaluronan in the joint fluids are reduced in osteoarthritis and rheumatoid arthritis. To elucidate the underlying mechanism, we analyzed the message expression of three isoforms of hyaluronan synthase and hyaluronidase from knee synovium, using real-time reverse transcriptase polymerase chain reaction. Synovia were obtained from 17 patients with osteoarthritis, 14 patients with rheumatoid arthritis, and 20 healthy control donors. The message expression of hyaluronan synthase-1 and -2 in the synovium of both types of arthritis was significantly less than in the control synovium, whereas that of hyaluronidase-2 in the synovium of both arthritides was significantly greater than in the control synovium. The decreased expression of the messages for hyaluronan synthase-1 and -2 and/or the increased expression of the message for hyaluronidase-2 may be reflected in the reduced concentration and decreased average molecular weight of hyaluronan in the joint fluids of patients with osteoarthritis and rheumatoid arthritis.

The effects of intraarticularly injected sodium hyaluronate on levels of intact aggrecan and nitric oxide in the joint fluid of patients with knee osteoarthritis

OBJECTIVE

Intraarticular injections of sodium hyaluronate (Na-HA) appear effective in reducing subjective symptoms of osteoarthritis (OA) and may also have protective effects on the cartilage matrix. The present study analyzed the suppressive effects of Na-HA on the release and degradation of aggrecan and on levels of nitric oxide (NO) in the joint fluid of patients with knee OA.

DESIGN

Sixteen OA patients with knee joint effusion were treated by 5 weekly intraarticular injections of Na-HA. Prior to each Na-HA injection, joint fluid was collected to determine the levels of chondroitin 4-sulfate (C4S) and chondroitin 6-sulfate (C6S), intact aggrecan and NO.

RESULTS

One week after the final injection, the joint fluid levels of C4S, C6S, and NO were significantly decreased. In contrast, the joint fluid level of intact aggrecan was stable during the series of Na-HA injections. A trend was seen for a positive correlation (P < 0.1) between the clinical score and C4S or C6S joint fluid levels, and for a negative correlation between the joint fluid levels of intact aggrecan and C4S or C6S. No significant correlations were observed between joint fluid levels of NO, the clinical score, and levels of C4S, C6S, and intact aggrecan.

CONCLUSION

The results of this study suggest that intraarticularly injected Na-HA is able to improve the clinical symptoms of OA partially based on its ability to reduce the release and degradation of aggrecan and/or to enhance the synthesis of aggrecan in the joint tissues of the patients with knee OA. While Na-HA also reduces the NO level in the joint fluid of patients with knee OA, this effect may be independent from the other effects of Na-HA.

Intra-articular hyaluronan therapy

Viscosupplementation, in which hyaluronan derivatives are injected into the intra-articular space of osteoarthritic joints, is now widely used to treat knee osteoarthritis (OA). No viscosupplements have been approved for osteoarthritic joints other than the knee. To date, no clinical trials using viscosupplements to treat ankle or foot OA have been published. However, the mechanisms thought to be responsible for viscosupplementation's therapeutic effects would likely apply in any synovial joint. A goal of this article is to stimulate interest in research to assess the potential role of viscosupplementation in treating foot and ankle OA.

The use of intra-articular Na-hyaluronate as a potential chondroprotective device in experimentally induced acute articular cartilage injury and repair in rabbits

OBJECTIVE

This study examined if viscosupplementation from intra-articular administration of a commercially available form of hyaluronan (HA) could promote the restoration of proteoglycan (PG) depletion induced by chymopapain and then if the repair could be maintained once HA treatment was discontinued.

METHODS

Animals received cartilage injury with intra-articular chymopapain (2.0 mg) followed by weekly treatment with intra-articular HA. HA treated animals were compared to injured animals with no treatment, contralateral untreated joints and joints from normal controls. The effect of intra-articular HA alone on articular cartilage was also examined.

RESULTS

Serum keratan sulfate levels confirmed degradation of the cartilage PGs in the chymopapain-injected knees. Intra-articular chymopapain resulted in marked loss of PGs. There were no significant differences among the control groups (untreated control, HA/800 treatment only). HA treatment did not affect the loss of PGs caused by chymopapain after 42 days. However, in animals receiving chymopapain injury followed by weekly HA treatment for 42 days and then 42 days of free cage activity without HA, cartilage PG contents were significantly increased. Intra-articular HA alone had no effect on the articular cartilage.

CONCLUSION

The results in the present study suggest a potential protective effect of HA on chymopapain-induced acute articular cartilage injury in rabbits that, in time, permits damaged cartilage to resynthesize matrix PGs after the HA treatment is discontinued.

High molecular weight hyaluronan promotes repair of IL-1 beta-damaged cartilage explants from both young and old bovines

OBJECTIVE

The addition of exogenous high molecular weight hyaluronic acid (HA) reverses cartilage damage caused by fibronectin fragments (Fn-fs) added to explant cultures of bovine and human cartilage and by Fn-fs in an experimental in vivo model of rabbit knee joint damage. Our objective was to test whether HA was also effective in an IL-1 damage model and whether this repair was stable and occurred in older bovine cartilage.

DESIGN

Bovine cartilage explants from 18-month-old or 6-year-old bovines in 10% serum/Dulbecco's modified Eagle's medium were exposed to Fn-f or to IL-1 and the ability of 1mg/ml HA of 800 kDa to block damage or promote restoration of proteoglycan (PG) after the damage was measured. The damage phase as well as the exposure to HA were varied.

RESULTS

Exposure of exogenous HA decreased Fn-f-mediated damage, but did not decrease IL-1 beta-induced cartilage damage. If explants from 18-month-old bovines were damaged by a 7-day exposure to Fn-f or IL-1 beta and then exposed for 7 days to HA, PG was restored. This reparative activity persisted up to 4 weeks after the removal of HA from the culture medium. The restoration of PG did not occur in 0.1% serum-free cultures, was less when the exposure to the Fn-f was doubled and failed when exposure to IL-1 beta was doubled. In explants from 6-year-old bovines damaged with IL-1 beta for 7 days, HA fully restored PG content to normal levels.

CONCLUSIONS

The reparative activities of HA occur not only in a Fn-f damage model, but also in an IL-1 damage model and occur with older bovine cartilage.

The effects of hyaluronic acid on fibronectin fragment mediated cartilage chondrolysis in skeletally mature rabbits

OBJECTIVE

Intraarticular Na-Hyaluronate (HA) exerts a beneficial effect on adolescent rabbits after fibronectin fragment (Fn-f) mediated cartilage injury. We extended our studies to a population of rabbits which have reached full skeletal maturity.

DESIGN

Adult male NZW rabbits received an injury with Fn-f and no further treatment; an injection of HA followed by Fn-f injury, or Fn-f injury followed by a single or weekly intraarticular injection of HA. All animals were sacrificed 38 days after receiving the Fn-f injury. After sacrifice, proteoglycan (PG) content was determined from articular cartilage from the medial femoral condyles and tibial plateaus. The patellae were processed for histology.

RESULTS

Cartilage PG contents were significantly reduced after Fn-f injection (P=0.0167) and were only slightly improved with HA pre-treatment. However, post-treatment with HA resulted in significant improvements in cartilage PG content when compared to Fn-f only (single HA, P=0.01; weekly HA,P =0.01). Loss of Safranin-O staining, cell loss, osteophyte formation and inflammation were present in the patellae following Fn-f injection. Pre-treatment with HA reduced these changes. More significant protection of cartilage and restoration of Fn-f injury were noted in animals receiving post-treatment with HA.

CONCLUSIONS

These results suggest that 38 days after Fn-f injury the lost PG content induced by Fn-f injection is substantially restored by weekly post-treatment with intraarticular HA in rabbits that have reached full skeletal maturity.

Intra-articular hyaluronan (hyaluronic acid) and hylans for the treatment of osteoarthritis: mechanisms of action

Although the predominant mechanism of intra-articular hyaluronan (hyaluronic acid) (HA) and hylans for the treatment of pain associated with knee osteoarthritis (OA) is unknown, in vivo, in vitro, and clinical studies demonstrate various physiological effects of exogenous HA. HA can reduce nerve impulses and nerve sensitivity associated with the pain of OA. In experimental OA, this glycosaminoglycan has protective effects on cartilage, which may be mediated by its molecular and cellular effects observed in vitro. Exogenous HA enhances chondrocyte HA and proteoglycan synthesis, reduces the production and activity of proinflammatory mediators and matrix metalloproteinases, and alters the behavior of immune cells. Many of the physiological effects of exogenous HA may be a function of its molecular weight. Several physiological effects probably contribute to the mechanisms by which HA and hylans exert their clinical effects in knee OA.

Chondrogenic differentiation of human mesenchymal stem cells within an alginate layer culture system

Human mesenchymal stem cells (hMSCs) derived from bone marrow have the capacity to differentiate along a number of connective tissue pathways and are an attractive source of chondrocyte precursor cells. When these cells are cultured in a three-dimensional format in the presence of transforming growth factor-beta, they undergo characteristic morphological changes concurrent with deposition of cartilaginous extracellular matrix (ECM). In this study, factors influencing hMSC chondrogenesis were investigated using an alginate layer culture system. Application of this system resulted in a more homogeneous and rapid synthesis of cartilaginous ECM than did micromass cultures and presented a more functional format than did alginate bead cultures. Differentiation was found to be dependent on initial cell seeding density and was interrelated to cellular proliferation. Maximal glycosaminoglycan (GAG) synthesis defined an optimal hMSC seeding density for chondrogenesis at 25 x 10(6) cells/ml. Inclusion of hyaluronan in the alginate layer at the initiation of cultures enhanced chondrogenic differentiation in a dose-dependent manner, with maximal effect seen at 100 microg/ml. Hyaluronan increased GAG synthesis at early time points, with greater effect seen at lower cell densities, signifying cell-cell contact involvement. This culture system offers additional opportunities for elucidating conditions influencing chondrogenesis and for modeling cartilage homeostasis or osteoarthritic changes.

Effects of hyaluronan on proteoglycan content of osteoarthritic chondrocytes in vitro

PURPOSE

To investigate the effect of hyaluronic acid (HA) on proteoglycan (PG) concentration in alginate cultures of human osteoarthritic chondrocytes and to analyze whether HA exhibit anti-degradative effects in the presence of the cytokine IL-1beta.

METHODS

Cartilage samples from ten patients with osteoarthritis of the knee were harvested and chondrocytes were cultivated in alginate beads. Four groups were cultured: control group with and without IL-1beta (500 pg/ml) and HA group (100 microg/ml) with and without IL-1beta (500 pg/ml). PG concentration was estimated by a dimethylmethylene blue assay. To assess cell proliferation, we measured DNA content fluorometrically.

RESULTS

The proliferation rate (DNA) was unchanged in all culture groups. In the control-group PG/DNA (ng/ng) concentration was 27.1 +/- 7.2. Supplementation of the medium with HA decreased PG concentration to 25.3 +/- 6.9 (p < 0.05). After administration of IL-1beta PG/DNA concentration dropped to 23.1 +/- 6.0 (p < 0.01). By contrast HA treatment of IL-1beta stimulated chondrocytes did not further decrease PG concentration (23.9 +/- 6.1). In fact the negative effect of isolated HA application was inverted if HA was given with IL-1beta (p < 0.05).

CONCLUSIONS

In osteoarthritic chondrocytes cultured phenotypically stable, HA could exhibit protective effects only in the presence of the degradative cytokine IL-1beta. Thus, the reported anti-inflammatory effects of HA to cartilage matrix seem to be more indirect by blocking degradative effects of cytokines to the matrix.

A single injection of fibronectin fragments into rabbit knee joints enhances catabolism in the articular cartilage followed by reparative responses but also induces systemic effects in the non-injected knee joints

OBJECTIVE

To investigate effects on cartilage metabolism and degeneration of injection of fibronectin fragments (Fn-fs) into rabbit knee joints.

DESIGN

The knees of adolescent New Zealand white rabbits were intraarticularly injected with rabbit Fn-fs. Cartilage sections from both injected and non-injected joints were treated with Safranin-O, with antibodies to the VDIPEN and NITEGE neoepitopes of degraded aggrecan and to matrix metalloproteinase-3 (MMP-3). Proteoglycan (PG) content of cartilage was measured by a dimethylmethylene blue assay of papain digests. PG synthesis rates were measured by(35)S-sodium sulfate incorporation into explanted cartilage.

RESULTS

In the injected joint cartilage, the Fn-fs bound cells in the upper superficial zone maximally between 6 and 24 h. By day 2, MMP-3 protein was enhanced and cartilage PG content and PG synthesis rates were reduced 40% and 70%, respectively. MMP-3 epitope and VDIPEN and NITEGE neoepitopes were also enhanced. The PG content then increased to supernormal levels from days 14 to 35 and then declined to normal levels by day 70, as did PG synthesis rates. In the non-injected joint cartilage, Fn-fs were not detected. Although MMP-3 expression was enhanced between days 2 and 21 as well as VDIPEN neoepitope, the PG content was never reduced but rather enhanced to supernormal levels from days 21 to 35. This was associated with enhanced PG synthesis by day 7, which decreased to control levels by day 70.

CONCLUSIONS

In this cartilage degeneration model, loss of cartilage PG is followed by supernormal anabolic responses that facilitate PG restoration. Further, the damage causes a systemic effect of enhanced PG synthesis and content in the non-injected joint cartilage.

Cartilage damage by matrix degradation products: fibronectin fragments

Catabolic cytokines play a major role in cartilage degradation not only in rheumatoid arthritis but also in osteoarthritis. Although the major source in rheumatoid arthritis may be mononuclear cells and synovial tissue and the cause of release may be multifactorial, the source of cytokines in osteoarthritis would be mostly from chondrocytes. However, there are few explanations of how upregulation of the cytokines might occur in osteoarthritis. One possibility is that degradation products of the extracellular matrix arising from elevated protease levels, substrate, or both, might regulate cytokine activities. Fragments of the extracellular matrix protein, fibronectin, upregulate cytokine expression and induce the events of suppressed matrix synthesis and upregulation of matrix metalloproteinases, characteristic of osteoarthritis. The catabolic aspects of this system are short term, subsequently serve to enhance anabolic processes above untreated levels, and condition the tissue against additional insult. It will be necessary to determine whether in vivo these degradation products precede cytokine expression and act early and are targets for intervention or instead are a consequence of cytokine damage. Whether they regulate anabolism and catabolism, blocking of their activities may not be ideal.

Effects of high molecular weight hyaluronan on the distribution and movement of proteoglycan around chondrocytes cultured in alginate beads

OBJECTIVE

To evaluate the effects of high molecular weight hyaluronan (HA) on the distribution and movement of proteoglycan (PG) formed around rabbit chondrocytes cultured in alginate beads.

DESIGN

Rooster comb-derived HA (MW 8x10(5) Da) was co-polymerized in alginate gel to study the direct effects of extrinsic HA on chondrocytes. PG metabolism of rabbit chondrocytes cultured in alginate beads was examined by measuring the incorporation of [(35)S]sulfate into glycosaminoglycan in two distinct regions, the cells with their cell-associated matrix (CM) and the further-removed matrix (FRM). Immunohistochemical analysis was performed using monoclonal antibodies against chondroitin sulfate and keratan sulfate. Autoradiography using degenerated cartilage tissue from the rabbit osteoarthritis (OA) model was performed to discover the effect of HA on the distribution of newly-synthesized PG in the cartilage tissue.

RESULTS

The incorporation of [(35)S]sulfate into newly-synthesized PG in the cells with CM decreased with the addition of 0.125-1.0 mg/ml HA, while the incorporation in the FRM increased. These effects of HA on the distribution of newly-synthesized PG were the same either in chondrocytes with CM or chondrocytes without CM. Immunohistochemical analysis showed that staining of PG in the CM was decreased and staining in the FRM was increased in the HA treated group compared to the control group. Autoradiography using degenerated cartilage tissue from the rabbit OA model indicated that [(35)S]-labeled macromolecules showed a more diffuse distribution in the HA treated group compared with the control group.

CONCLUSION

These results indicate that extrinsic HA could affect the movement of newly-synthesized PG from the CM to the FRM in both alginate beads and cartilage tissue.

Clinical evaluation of sodium hyaluronate for the treatment of patients with rotator cuff tear

A randomized study of two types of conservative treatment of 78 shoulders in 78 patients with rotator cuff tears was performed. Twenty-five milligrams of sodium hyaluronate (SH) was injected into shoulders in one group (SH group) and 2 mg of dexamethasone was injected in the other group (steroid group). Injection of each drug was planned for once per week for 5 consecutive weeks. In the SH group, University of California at Los Angeles score before treatment was 13.6 +/- 2.6 points in 16 patients who did not require surgery (satisfied patients) and 12.8 +/- 3.5 points in 22 patients who required surgery (unsatisfied patients) (not statistically significant). In the steroid group, University of California at Los Angeles score before treatment was 11.9 +/- 3.6 points for 15 satisfied patients and 12.6 +/- 3.9 points for 25 unsatisfied patients (again, not statistically significant). In the SH group, the score at 4 weeks after treatment for satisfied patients increased to 27.6 +/- 3.1 points, whereas that for unsatisfied patients was 14.9 +/- 1.2 points (P <.0001). Similarly, in the steroid group, the score at 4 weeks after the treatment for satisfied patients increased to 26.5 +/- 2.0 points, whereas that for unsatisfied patients was 15.0 +/- 4.0 points (P <.0001). At 24 weeks after treatment, the score for satisfied patients was 26.2 +/- 3.1 points in the SH group and 25.3 +/- 2.5 points in the steroid group. The effective rate of the SH group was 39.5% and that of the steroid group was 35%. Therapeutic efficacy in the SH group was equivalent to that in the steroid group. In both groups, the rate of patients who engaged in manual labor was significantly higher in the group of unsatisfied patients than in that of satisfied patients. No adverse reaction to either treatment was observed. These results suggest that SH is an effective conservative treatment for patients with rotator cuff tears.

Hyaluronan does not affect cytokine and chemokine expression in osteoarthritic chondrocytes and synoviocytes

OBJECTIVE

Many studies have evidenced the clinical efficacy of hyaluronan (HA) in the treatment of osteoarthritis (OA). However, human and animal studies have described proinflammatory effects of HA on cells not involved in OA. We therefore investigated whether different molecular weight HA preparations can affect proinflammatory cytokine (IL1beta and TNFalpha) or chemokine (IL8, MCP-1 and RANTES) expression in human chondrocytes and synoviocytes isolated from OA patients.

DESIGN

Human chondrocytes and synoviocytes were cultured in vitro in the presence or absence of three different purified HA pharmaceutical preparations (1x10(6) Kd, 5x10(5) Kd and 6.5x10(4) Kd) and assessed for the production of proinflammatory cytokines and chemokines and their mRNA expression.

RESULTS

basal conditions, both chondrocytes and synoviocytes produce only MCP-1 and IL8, along with low quantities of IL1beta and TNFalpha, but not RANTES. IL8 production was generally about 100 times higher in chondrocytes than in synoviocytes, while MCP-1 was roughly twice as high in synoviocytes than in chondrocytes. At the mRNA level, expression of IL1beta, TNFalpha, IL8, MCP-1 and RANTES did not change in the presence of the three HA preparations either in synoviocytes or in chondrocytes with respect to basal condition. None of the three different HA preparations significantly affected production of IL8 or MCP-1.

CONCLUSIONS

These data demonstrate that preparations of HA of the same origin but with different MWs do not induce proinflammatory cytokines and chemokines expressed by chondrocytes and synoviocytes that are either directly or indirectly involved in OA progression.

The effects of glucosamine derivatives on equine articular cartilage degradation in explant culture

OBJECTIVE

To determine whether glucosamine-3-sulfate, glucose-3-sulfate (control) and N-acetyl glucosamine inhibit experimentally induced degradation of equine articular cartilage explants similar to glucosamine HCl.

DESIGN

Articular cartilage was obtained from the antebrachio-carpal and middle joints of horses (2-8 years old) killed for reasons unrelated to lameness. Cartilage discs were harvested from the weight-bearing region of the articular surface and cultured. Media were exchanged daily and the recovered media stored at 4 degrees C. On days 1 and 2 lipopolysaccharide (LPS, 10 microg/ml) was added to induce cartilage degradation. To evaluate the effects of different sources of glucosamine (on an equal molar basis), varying concentrations of glucosamine HCl (0.25, 2.5, or 25 mg/ml), glucosamine-3-sulfate (0.304, 3.04, or 30.4 mg/ml), or N-acetyl-glucosamine (0.256, 2.56, or 25.6 mg/ml) were added to the cultures. The glucose-3-sulfate control was added at 0.3075, 3.075 or 30.75 mg/ml. Nitric oxide and proteoglycan released into conditioned media and tissue proteoglycan synthesis and total tissue PG content were measured as indicators of cartilage metabolism.

RESULTS

Glucosamine-3-sulfate consistently inhibited cartilage degradation in a manner similar to glucosamine HCl, while the effects of N-acetyl-glucosamine were highly variable and did not inhibit cartilage degradation. Glucose-3-sulfate did not inhibit cartilage degradation.

CONCLUSION

Our results indicate that glucosamine sulfate also has the potential to prevent or reduce articular cartilage degradation similar to glucosamine HCl in vitro. The amine group at the carbon-2 position appears important for the effectiveness of the glucosamine derivative. The therapeutic value of N-acetyl-glucosamine remains questionable.