Glucosamine sulfate modulates dysregulated activities of human osteoarthritic chondrocytes in vitro

Oral supplementation with fish cartilage hydrolysate in an adult population suffering from knee pain and function discomfort: results from an innovative approach combining an exploratory clinical study and an ex vivo clinical investigation

BACKGROUND

Aging is frequently associated with impairments of the musculoskeletal system and many elderly people experience joint discomfort or pain which might reduce their ability to move and consequently alter their quality of life. A beneficial effect of fish cartilage hydrolysate (FCH) on pain and joint function has recently been shown in an ACLT/pMMx osteoarthritis rat model.

METHODS

We therefore performed an exploratory, non-comparative, multi-centric clinical trial including 33 subjects with moderate knee joint discomfort and loss of functionality to investigate the efficacy of FCH on their algo-functional status. We further determined the potential health benefit of FCH in an original clinical ex vivo study investigating the role of FCH human metabolites on primary human chondrocytes.

RESULTS

FCH significantly improved knee pain and function, as assessed by the Knee injury and Osteoarthritis Outcome Score (KOOS). Moreover, FCH significantly reduced pain at rest and while walking, and patient global assessment (PGA), as assessed by the Visual Analogue Scale (VAS), and improved patients' quality of life (SF-36). FCH metabolites decreased the synthesis of catabolic factors (MMP-13) and pro-inflammatory mediators (NO, PGE2) and limited the inhibitory effect of IL-1β on the synthesis of cartilage matrix components (GAG and collagen).

CONCLUSIONS

Thus, these data provide insights on the mode of action of FCH in humans and contribute to explain how FCH may relieve pain and improve joint function in subjects with knee discomfort. Although these preliminary data need to be confirmed in a randomized controlled trial, they strongly support the potential health benefit of such an active ingredient.

TRIAL REGISTRATION

The study was registered on clinicaltrials.gov with the identifier NCT04420091 (09/06/2020).

Treatment of knee osteoarthritis with a new formulation of a fixed-dose combination of glucosamine sulfate and bovine chondroitin: a multicenter, randomized, single-blind, non-inferiority clinical trial

OBJECTIVES

To compare the efficacy and safety of a new formulation of a fixed dose combination of glucosamine sulfate (GS; 1500 mg) and bovine chondroitin sulfate (CS; 1200 mg) versus the reference product (RP) in patients with knee osteoarthritis (OA).

METHODS

In this multicenter, randomized, single-blind trial, 627 patients with knee osteoarthritis (OA)-Kellgren-Lawrence grades 2 or 3 and mean score ≥ 40 mm in the WOMAC pain subscale-were randomized to receive GS/CS or the RP for 24 weeks. The primary efficacy endpoint was the absolute change in WOMAC pain subscale score. The secondary endpoints included the following: WOMAC total and subscale scores, overall assessment of the disease by the patient and the investigator, SF-12 score, OMERACT-OARSI response rate to the treatment, and rescue medication use.

RESULTS

Mean reductions of WOMAC pain score were - 35.1 (sd = 23.2) mm in the GS/CS group and - 36.5 (sd = 24.9) mm in the RP group. The difference between the adjusted means of both treatments confirmed the non-inferiority of GS/CS versus the RP. Improvement was observed in pain, stiffness, physical function and total WOMAC score, as well as in overall OA assessment by the patient and the investigator for both groups. No improvement was observed in SF-12. The rate of OMERACT-OARSI responders was 89.4% in GS/CS group and 87.9% in the RP group. Headache and changes in glucose tolerance were the most frequent treatment-related adverse events.

CONCLUSIONS

The new formulation of a fixed-dose combination of glucosamine sulfate and bovine chondroitin sulfate was non-inferior to the RP in symptomatic treatment of knee OA, with a high responder rate and good tolerability profile.

TRIAL REGISTRATION

ClinicalTrials.gov; Registration number NCT02830919 ; Date of registration: July 13, 2016; First randomization date: December 05, 2016).

Role of Orthoboon (glucosamine sulfate + collagen + Vitamin C): A novel host-modulating agent in the management of chronic periodontitis

Background:

Recent trends suggest using novel host-modulating agents as a treatment strategy for chronic periodontitis. Glucosamine sulfate (GS) was proven to have anti-inflammatory actions related to its ability to suppress neutrophil functions. Orthoboon, an anti-arthritic and anti-inflammatory drug, has shown to have a positive therapeutic effect due to its constituents made of a combination of GS, Vitamin C, and collagen. The aim of the study was to evaluate the host modulatory effects of Orthoboon on periodontal status and to estimate the C reactive protein (CRP) levels before and after nonsurgical periodontal therapy (NSPT).

Materials and Methods:

A total number of 40 patients with chronic periodontitis were randomly divided into two groups of 20 patients each. The test group patients (n = 20) received 500 mg Orthoboon three times daily for 45 days. Prior to the initiation of Orthoboon, all patients in both test group and control group were subjected to Phase I periodontal therapy. CRP levels were estimated immediately after phase I therapy and 45 days after therapy. Clinical parameters including plaque index, gingival index, and bleeding index were recorded before and after NSPT for the two groups.

Results:

The mean CRP levels were reduced significantly in the test group before and after administration of Orthoboon and also there were statistically significant differences in the mean CRP levels at the end of 45 days between the test group and the control group.

Conclusion:

Administration of Orthoboon, i.e., GS, with a combination of Vitamin C and collagen was proved to be of a significant benefit in the test group than in the control group.

Glucosamine sulphate-loaded distearoyl phosphocholine liposomes for osteoarthritis treatment: combination of sustained drug release and improved lubrication

Osteoarthritis (OA) is a chronic joint disease resulting from joint inflammation and damage. In this study, we employed a boundary lubricant known as a 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) liposome for loading of an anti-inflammatory drug d-glucosamine sulphate (GAS) to construct a treatment strategy allowing for sustained anti-inflammation and reduced damage. This kind of drug-loaded nanocarrier integrates the anti-inflammatory effect of the GAS and the lubrication ability of DSPC liposomes without the involvement of complex synthesis processes leading to easier popularization. Our experimental results indicated that the GAS-loaded DSPC liposomes could release GAS in a sustained manner while providing good lubrication in pure water (H2O) and phosphate buffered saline (PBS). Moreover, the GAS-loaded DSPC liposomes prepared at a 2 : 8 molar ratio in PBS exhibited a greater entrapment efficiency, lower GAS release rate and smaller friction coefficient as compared to those prepared in H2O. The superiority of the drug release and lubrication ability achieved with the GAS-loaded DSPC liposomes in PBS were elucidated on the basis of salt-induced enhancement in liposomal stability and hydration lubrication by the hydrated salt ions. Such GAS release accelerated the viability and proliferation of primary mouse chondrocytes while also providing the anti-inflammatory and chondroprotective potential for tumor necrosis factor (TNF-α) induced chondrocyte degeneration through the down-regulation of pro-inflammatory cytokines, pain related gene and catabolic proteases, as well as the up-regulation of anabolic components. We envision that the GAS-loaded DSPC liposomes could represent a promising new strategy for clinical treatment of OA in the future.

Multifaceted Protective Role of Glucosamine against Osteoarthritis: Review of Its Molecular Mechanisms

Osteoarthritis (OA) is a joint disease resulting from cartilage degeneration and causing joint pain and stiffness. Glucosamine exerts chondroprotective effects and effectively reduces OA pain and stiffness. This review aims to summarise the mechanism of glucosamine in protecting joint health and preventing OA by conducting a literature search on original articles. Current evidence has revealed that glucosamine exhibits anti-inflammatory effects by reducing the levels of pro-inflammatory factors (such as tumour necrosis factor-alpha, interleukin-1, and interleukin-6) and enhancing the synthesis of proteoglycans that retard cartilage degradation and improve joint function. Additionally, glucosamine improves cellular redox status, reduces OA-mediated oxidative damages, scavenges free radicals, upregulates antioxidant proteins and enzyme levels, inhibits the production of reactive oxygen species, and induces autophagy to delay OA pathogenesis. In conclusion, glucosamine prevents OA and maintains joint health by reducing inflammation, improving the redox status, and inducing autophagy in joints. Further studies are warranted to determine the synergistic effect of glucosamine with other anti-inflammatory and/or antioxidative agents on joint health in humans.

[Alflutop - in modern symptom - modifying osteoarthritis therapy]

One of the serious problems during the treatment of osteoarthritis (OA) is the developing of adverse drug events during therapy. Nonsteroidal anti - inflammatory drugs (NSAIDs) are the first drugs with the high incidence and severity of adverse events. This article describes OA treatment strategies approaches for OA are presented using the complex drug Alflutop, which has a composition similar to the human hyaline cartilage. The drug has anti - inflammatory and analgesic effects, normalizes the function of the affected joints, improves the quality of patients' life, also has a structure - modifying effect. Such therapy is safe, well tolerable for patients, and can be used used as a starting complex OA treatment.

Glucosamine-modified polyethylene glycol hydrogel-mediated chondrogenic differentiation of human mesenchymal stem cells

Glucosamine (GA) is an important cartilage matrix precursor for the glycosaminoglycan biochemical synthesis, and has positive effects on cartilage regeneration, particularly in osteoarthritis therapy. However, it has not been used as a bioactive group in scaffolds for cartilage repair widely. In this study, we synthesized modified polyethylene glycol (PEG) hydrogel with glucosamine and then encapsulated human bone mesenchymal stem cells (hBMSCs) in the hydrogel to induce the differentiation of hBMSCs into chondrocytes in three-dimensional culture. The GA-modified PEG hydrogels promoted the chondrogenesis of hBMSCs, particularly in the concentration of 5mM and 10mM. The subcutaneous transplantation of 10mM GA-modified hydrogels with hBMSCs formed cartilage-like blocks in vivo for 8weeks. Importantly, with glucosamine increase, the modified hydrogels down-regulated the fibrosis and hypertrophic cartilage markers in protein level. Therefore, glucosamine modified PEG hydrogels facilitated the chondrogenesis of hBMSCs, which might represent a new method for cartilage repair using a tissue-engineering approach.

Glucosamine and chondroitin for the treatment of osteoarthritis

The prevalence of primary or idiopathic osteoarthritis (OA) of knee and hip joints has substantially increased in general population during the last decades. Analgesics and non-steroidal anti-inflammatory drugs are currently extensively used as non-surgical treatment options. However, they act as symptomatic treatments, not offering a cure of OA and they are accused for an increased risk of adverse events. Glucosamine (GL) and chondroitin (CH) are nutritional supplements that have recently gained widespread use as treatment options for OA. They potentially or theoretically act as chondroprotectors or/and as “disease-modifying OA drugs” offering not only symptomatic relief but also alteration of the natural history of OA. However, although many studies have showed a significant treatment effect, accompanied with remarkable safety, there is still controversy regarding their relative effectiveness compared with placebo or other treatments. The scope of this review is to present and critically evaluate the current evidence-based information regarding the administration of GL and CH for the treatment of knee or hip OA. Our focus is to investigate the clinical efficacy and safety after the use of these supplements. An effect of GL and CH on both clinical and radiological findings has been shown. However, only a few high-quality level I trials exist in the literature, especially on the assessment of radiological progression of OA. The effect sizes are generally small and probably not clinically relevant. Even the validity of these results is limited by the high risk of bias introduced in the studies. Both GL and CH seem to be safe with no serious adverse events reported. There is currently no convincing information for the efficacy of GL and CH on OA.

Clinical Evaluation of the Efficacy of Arthocare Forte, a Chondro-Protective and Anti-Arthritic Drug in the Management of Bacterial Plaque-Induced Chronic Periodontitis

BACKGROUND

Arthocare forte medication is made up of different constituents and the advantages offered by this disposition have not been explored in the management of chronic periodontitis.

AIM

The aim was to assess the clinical response of bacterial plaque-induced generalized chronic periodontitis to arthocare medication, and the relationship of age and gender to the prevalence of chronic periodontal disease.

SUBJECTS AND METHODS

This study was done at the Dental Surgery Clinic of the University of Calabar Teaching Hospital, Nigeria. It was a Prospective randomized controlled trial evaluating the effect of arthocare treatment on 81/162 patients with teeth mobility over a period of 5 years. All the patients (162) underwent root planing, and 81/162 (50%) were treated with arthocare for comparative analysis. The variables recorded were patient's age, gender, and degree of tooth mobility, periodontal pocket, and bleeding from the pocket after treatment. Statistical analysis was done using EPI INFO 7.

RESULTS

Majority of the patients were between 46 and 75 years in both control (n = 59/81, 72.8%) and experimental groups (n = 52/81, 64.2%). There were 86/162 (53.1%) males and 76/162 (46.9%) females, giving a male-to-female ratio of 1.1:1. Seventy-seven patients (95.1%) in the experimental group had total remission in comparison to 32/81 (39.5%) in control group which was statistically significant (P < 0.001).

CONCLUSION

The arthocare administered to patients in the experimental group speeds up the regenerative capacity and stability of the periodontium when compared with the control. Multicentre clinical trials are recommended to validate the use of arthocare forte in the treatment of generalized chronic periodontitis.

Glucosamine supplementation demonstrates a negative effect on intervertebral disc matrix in an animal model of disc degeneration

STUDY DESIGN

Laboratory based controlled in vivo study.

OBJECTIVE

To determine the in vivo effects of oral glucosamine sulfate on intervertebral disc degeneration.

SUMMARY OF BACKGROUND DATA

Although glucosamine has demonstrated beneficial effect in articular cartilage, clinical benefit is uncertain. A Centers for Disease Control report from 2009 reported that many patients are using glucosamine supplementation for low back pain, without significant evidence to support its use. Because disc degeneration is a major contributor of low back pain, we explored the effects of glucosamine on disc matrix homeostasis in an animal model of disc degeneration.

METHODS

Eighteen skeletally mature New Zealand White rabbits were divided into 4 groups: control, annular puncture, glucosamine, and annular puncture + glucosamine. Glucosamine treated rabbits received daily oral supplementation with 107 mg/d (weight based equivalent to human 1500 mg/d). Annular puncture surgery involved puncturing the annulus fibrosus of 3 lumbar discs with a 16-gauge needle to induce degeneration. Serial magnetic resonance images were obtained at 0, 4, 8, 12, and 20 weeks. Discs were harvested at 20 weeks for determination of glycosaminoglycan content, relative gene expression measured by real time polymerase chain reaction, and histological analyses.

RESULTS

The magnetic resonance imaging index and nucleus pulposus area of injured discs of glucosamine treated animals with annular puncture was found to be lower than that of degenerated discs from rabbits not supplemented with glucosamine. Consistent with this, decreased glycosaminoglycan was demonstrated in glucosamine fed animals, as determined by both histological and glycosaminoglycan content. Gene expression was consistent with a detrimental effect on matrix.

CONCLUSION

These data demonstrate that the net effect on matrix in an animal model in vivo, as measured by gene expression, magnetic resonance imaging, histology, and total proteoglycan is antianabolic. This raises concern about this commonly used supplement, and future research is needed to establish the clinical relevance of these findings.

Physiological effects of oral glucosamine on joint health: current status and consensus on future research priorities

The aim of this paper was to provide an overview of the current knowledge and understanding of the potential beneficial physiological effects of glucosamine (GlcN) on joint health. The objective was to reach a consensus on four critical questions and to provide recommendations for future research priorities. To this end, nine scientists from Europe and the United States were selected according to their expertise in this particular field and were invited to participate in the Hohenheim conference held in August 2011. Each expert was asked to address a question that had previously been posed by the chairman of the conference. Based on a systematic review of the literature and the collection of recent data, the experts documented the effects of GlcN on cartilage ageing, metabolic/kinetic and maintenance of joint health as well as reduction of risk of OA development. After extensive debate and discussion the expert panel addressed each question and a general consensus statement was developed, agreeing on the current state-of-the-art and future areas for basic and clinical studies. This paper summarizes the available evidence for beneficial effects of GlcN on joint health and proposes new insight into the design of future clinical trials aimed at identifying beneficial physiological effect of GlcN on joint tissues.

Crystalline glucosamine sulfate in the management of knee osteoarthritis: efficacy, safety, and pharmacokinetic properties

Glucosamine is an amino monosaccharide and a natural constituent of glycosaminoglycans in articular cartilage. When administered exogenously, it is used for the treatment of osteoarthritis as a prescription drug or a dietary supplement. The latter use is mainly supported by its perception as a cartilage building block, but it actually exerts specific pharmacologic effects, mainly decreasing interleukin 1-induced gene expression by inhibiting the cytokine intracellular signaling cascade in general and nuclear factor-kappa B (NF-kB) activation in particular. As a whole, the use of glucosamine in the management of osteoarthritis is supported by the clinical trials performed with the original prescription product, that is, crystalline glucosamine sulfate. This is the stabilized form of glucosamine sulfate, while other formulations or different glucosamine salts (e.g. hydrochloride) have never been shown to be effective. In particular, long-term pivotal trials of crystalline glucosamine sulfate 1500 mg once daily have shown significant and clinically relevant improvement of pain and function limitation (symptom-modifying effect) in knee osteoarthritis. Continuous administration for up to 3 years resulted in significant reduction in the progression of joint structure changes compared with placebo as assessed by measuring radiologic joint space narrowing (structure-modifying effect). The two effects combined may suggest a disease-modifying effect that was postulated based on an observed decrease in the risk of undergoing total joint replacement in the follow up of patients receiving the product for at least 12 months in the pivotal trials. The safety of the drug was good in clinical trials and in the postmarketing surveillance. Crystalline glucosamine sulfate 1500 mg once daily is therefore recommended in the majority of clinical practice guidelines and was found to be cost effective in pharmacoeconomic analyses. Compared with other glucosamine formulations, salts, or dosage forms, the prescription product achieves higher plasma and synovial fluid concentrations that are above the threshold for a pharmacologically relevant effect, and may therefore justify its distinct therapeutic characteristics.

Effect of a dietary supplement containing glucosamine hydrochloride, chondroitin sulfate and quercetin glycosides on symptomatic knee osteoarthritis: a randomized, double-blind, placebo-controlled study

BACKGROUND

Oral glucosamine and chondroitin sulfate, alone and in combination, have been used worldwide for the treatment of osteoarthritis (OA), but their efficacy is controversial. This clinical study was aimed at investigating the potential of a dietary supplement containing glucosamine and chondroitin sulfate in combination with derivatives of quercetin, a naturally occurring flavonoid, (GCQ supplement) for knee OA care.

RESULTS

A randomized, double-blind, placebo-controlled study was conducted in 40 Japanese subjects with symptomatic knee OA. Subjects were randomly assigned to GCQ supplement (1200 mg glucosamine hydrochloride, 60 mg chondroitin sulfate and 45 mg quercetin glycosides per day) or placebo and the treatment and follow-up were continued for 16 weeks. The results of symptomatic efficacy assessment based on Japanese Orthopaedic Association criteria showed that scores for two of the four symptom/function subscales, as well as the aggregate scores, were significantly improved at week 16 or earlier in the GCQ group compared to the placebo group. Moreover, analyses of cartilage metabolism biomarkers showed a trend of improvement in type II collagen synthesis/degradation balance in the GCQ group during follow-up.

CONCLUSION

GCQ supplement was thought to be more effective than placebo in decreasing the intensity of knee OA-associated clinical symptoms.

Is there any scientific evidence for the use of glucosamine in the management of human osteoarthritis?

Glucosamine in its acetylated form is a natural constituent of some glycosaminoglycans (for example, hyaluronic acid and keratan sulfate) in the proteoglycans found in articular cartilage, intervertebral disc and synovial fluid. Glucosamine can be extracted and stabilized by chemical modification and used as a drug or a nutraceutical. It has been approved for the treatment of osteoarthritis (OA) in Europe to promote cartilage and joint health and is sold over the counter as a dietary supplement in the United States. Various formulations of glucosamine have been tested, including glucosamine sulfate and glucosamine hydrochloride. In vitro and in vivo studies have uncovered glucosamine's mechanisms of action on articular tissues (cartilage, synovial membrane and subchondral bone) and justified its efficacy by demonstrating structure-modifying and anti-inflammatory effects at high concentrations. However, results from clinical trials have raised many concerns. Pharmacokinetic studies have shown that glucosamine is easily absorbed, but the current treatment doses (for example, 1,500 mg/day) barely reach the required therapeutic concentration in plasma and tissue. The symptomatic effect size of glucosamine varies greatly depending on the formulation used and the quality of clinical trials. Importantly, the effect size reduces when evidence is accumulated chronologically and evidence for the structure-modifying effects of glucosamine are sparse. Hence, glucosamine was at first recommended by EULAR and OARSI for the management of knee pain and structure improvement in OA patients, but not in the most recent NICE guidelines. Consequently, the published recommendations for the management of OA require revision. Glucosamine is generally safe and although there are concerns about potential allergic and salt-related side effects of some formulations, no major adverse events have been reported so far. This paper examines all the in vitro and in vivo evidence for the mechanism of action of glucosamine as well as reviews the results of clinical trials. The pharmacokinetics, side effects and differences observed with different formulations of glucosamine and combination therapies are also considered. Finally, the importance of study design and criteria of evaluation are highlighted as new compounds represent new interesting options for the management of OA.

The effectiveness of Echinacea extract or composite glucosamine, chondroitin and methyl sulfonyl methane supplements on acute and chronic rheumatoid arthritis rat model

The study aimed to investigate the effect of the oral administration for 15 days of either Echinacea (E) or genuphil (a composite of chondroitin sulphate, glucosamine and methyl sulfonyl methane [GCM]) nutraceutical supplements on female rat model of acute or chronic arthritis induced by bacterial outer membrane protein (OMP) from faecal flora of healthy and rheumatic humans. Anti-cyclic citrullinated peptide (anti-CCP2), C-reactive protein (CRP) and rheumatoid factor (RF) values increased ( p < 0.05) in both arthritic groups as compared to normal values. The rheumatic markers anti-CCP2, CRP and RF values decreased significantly in E- and GCM-treated groups compared to arthritic none-treated acute or chronic groups. The results of RF values of GCM-treated groups in acute and chronic models decreased exhibiting no statistical difference compared with the normal value. Histological examinations of the hind paw sections revealed moderate inflammation, oedema and mild proliferation of synovial cells in acute arthritic rats and more damage to cartilage and bone with severe inflammation in chronic ones. Echinacea acute treated group showed edema with proliferated synovial membrane and partial damage in cartilage and bone. While in the E -chronic treated group, rough edge with destructed cartilage and bone existed. However, the acute GCM group revealed mild cartilage damage. But the chronic GCM group showed mild synovial cells proliferation and revealed no inflammation with mild cartilage damage edge. Results demonstrated the OMP arthropathic property and through promising light on arthritis treatment using E- or GCM, with the advantage of GMC results over that of E -. The composite GCM is needed for further studies over the dose and duration to assess its preventive effects against the bacterial OMP arthrogenicity.

Effect of a glucosamine-based combination supplement containing chondroitin sulfate and antioxidant micronutrients in subjects with symptomatic knee osteoarthritis: A pilot study

In the present study, we aimed to investigate the potential effect of a glucosamine (1,200 mg/day)-based dietary supplement combined with chondroitin sulfate and three antioxidant micronutrients, namely methylsulfonylmethane, guava leaf extract, and vitamin D (test supplement) on osteoarthritis (OA) of the knee. A 16-week, randomized, double-blinded, placebo-controlled trial was conducted involving 32 subjects with symptomatic knee OA. Clinical outcomes were measured using the Japanese Knee Osteoarthritis Measure (JKOM) for symptoms and a study diary-based visual analog scale (diary VAS) for pain at baseline and at weeks 4, 8, 12 and 16 during the 16-week intervention period. Furthermore, biomarkers for cartilage type II collagen degradation (C2C) and synovitis hyaluronan (HA) were measured. As compared with the baseline, the JKOM pain subscale was significantly improved at all of the four assessment time points in the test group, but was not at any time point in the placebo group. On the other hand, all of the four symptom subscales and the aggregated total symptoms were significantly improved in the two groups at one or more time points. However, all of these clinical improvements were greater in extent in the test group than in the placebo group, and there were significant differences between groups in the magnitude of changes from baseline for one subscale 'general activities' and the aggregated total symptoms at week 8 (P<0.05). The results of efficacy assessments with the diary VAS showed that all of the three pain subscales were significantly improved only in the test group at almost all the time points. Moreover, serum levels of C2C and HA were decreased by 10 and 25%, respectively, at week 16 in the test group, albeit not statistically significant, without any detectable changes in the placebo group. In conclusion, although the results obtained in this study were not conclusive, the tested glucosamine-based combination supplement is likely to have a beneficial effect on pain and other symptoms associated with knee OA.

Comparison of glucose derivatives effects on cartilage degradation

BACKGROUND

Glucosamine (GlcN) is a well-recognized candidate for treatment of osteoarthritis. However, it is currently used in derivative forms, such as glucosamine-hydrochloride (GlcN-HCl) or glucosamine sulfate (GlcN-S). However, the molecular mode of action remains unclear. In this study, we compared the effects of Glucose (Glc), Glucuronic acid (GlcA), Glucosamine hydrochloride (GlcN-HCl) and Glucosamine sulfate (GlcN-S) on cartilage degradation.

METHODS

Porcine cartilage explants were co-cultured with recombinant human IL-1beta and each tested substance for 3 days. HA, s-GAG and MMP-2 releases to media were measured using ELISA, dye-binding assay and gelatin zymography, respectively. Similar studies were performed in a human articular chondrocytes (HAC) monolayer culture, where cells were co-treated with IL-1beta and each reagent for 24 hours. Subsequently, cells were harvested and gene expression measured using RT-PCR. All experiments were carried out in triplicate. Student's t-tests were used for statistical analysis.

RESULTS

In cartilage explants treated with IL-1beta, GlcN-S had the highest chondroprotective activity of all four chemicals as shown by the inhibition of HA, s-GAG and MMP-2 released from cartilage. The anabolic (aggrecan core protein; AGG, SOX9) and catabolic (MMP-3, -13) genes in HACs treated with IL-1beta and with/without chemicals were studied using RT-PCR. It was found that, GlcN-HCl and GlcN-S could reduce the expression of both MMP-3 and -13 genes. The IL-1beta induced-MMP-13 gene expression was decreased maximally by GlcN-S, while the reduction of induced-MMP-3 gene expression was greatest with GlcN-HCl. Glc and GlcA reversed the effect of IL-1beta on the expression of AGG and SOX9, but other substances had no effect.

CONCLUSION

This study shows that glucosamine derivatives can alter anabolic and catabolic processes in HACs induced by IL-1beta. GlcN-S and GluN-HCl decreased induced MMP-3 and -13 expressions, while Glc and GlcA increased reduced-AGG and SOX9 expression. The chondroprotective study using porcine cartilage explant showed that GlcN-S had the strongest effect.

Pharmacoproteomic study of the effects of chondroitin and glucosamine sulfate on human articular chondrocytes

INTRODUCTION

Chondroitin sulfate (CS) and glucosamine sulfate (GS) are symptomatic slow-acting drugs for osteoarthritis (OA) widely used in clinic. Despite their widespread use, knowledge of the specific molecular mechanisms of their action is limited. The aim of this work is to explore the utility of a pharmacoproteomic approach for the identification of specific molecules involved in the pharmacological effect of GS and CS.

METHODS

Chondrocytes obtained from three healthy donors were treated with GS 10 mM and/or CS 200 μg/mL, and then stimulated with interleukin-1β (IL-1β) 10 ng/mL. Whole cell proteins were isolated 24 hours later and resolved by two-dimensional electrophoresis. The gels were stained with SYPRORuby. Modulated proteins were identified by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF/TOF) mass spectrometry. Real-time PCR and Western blot analyses were performed to validate our results.

RESULTS

A total of 31 different proteins were altered by GS or/and CS treatment when compared to control. Regarding their predicted biological function, 35% of the proteins modulated by GS are involved in signal transduction pathways, 15% in redox and stress response, and 25% in protein synthesis and folding processes. Interestingly, CS affects mainly energy production (31%) and metabolic pathways (13%), decreasing the expression levels of ten proteins. The chaperone GRP78 was found to be remarkably increased by GS alone and in combination with CS, a fact that unveils a putative mechanism for the reported anti-inflammatory effect of GS in OA. On the other hand, the antioxidant enzyme superoxide dismutase 2 (SOD2) was significantly decreased by both drugs and synergistically by their combination, thus suggesting a drug-induced decrease of the oxidative stress caused by IL-1β in chondrocytes.

CONCLUSIONS

CS and GS differentially modulate the proteomic profile of human chondrocytes. This pharmacoproteomic approach unravels the complex intracellular mechanisms that are modulated by these drugs on IL1β-stimulated human articular chondrocytes.

Conservative treatment modalities and outcomes for osteoarthritis: the concomitant pyramid of treatment

This article reviews current treatment algorithms for the conservative treatment of hip and knee osteoarthritis. The available treatment options for osteoarthritis (physical therapy, medical therapeutics, steroid injections, nutraceuticals, hyaluronic acid injections, acupuncture, pulsed electrical stimulation, and topical ointments) are compared to determine efficacy in the treatment of pain and return of function in the osteoarthritic joint. A literature review was conducted to determine combinations of appropriate concomitant therapy. Based on the available literature, we conclude that an early transition to multimodal and concomitant therapy is the most efficacious approach to decrease pain and improve joint function in the osteoarthritic hip and knee.

The effects of oral glucosamine on joint health: is a change in research approach needed?

OBJECTIVE

Oral glucosamine (GlcN) has been widely studied for its potential therapeutic benefits in alleviating the pain and disability of osteoarthritis (OA). Its popularity has grown despite ongoing controversy regarding its effectiveness vs placebo in clinical trials, and lack of information regarding possible mechanisms of action. Here, we review the state of knowledge concerning the biology of GlcN as it relates to OA, and discuss a framework for future research directions.

METHODS

An editorial "narrative" review of peer-reviewed publications is organized into four topics (1) Chemistry and pharmacokinetics of GlcN salts (2) Biological effects of GlcN salts in vitro (3) Therapeutic effects of GlcN salts in animal models of OA and (4) GlcN salts in the treatment of clinical OA.

RESULTS

Data reporting potent pleiotropic activities of GlcN in in vitro cell and explant cultures are discussed in the context of the established pharmacokinetic data in humans and animals. The available clinical trial data are discussed to place the patient in the context of controlled research on disease management.

CONCLUSIONS

Future research to determine therapeutic mechanisms of GlcN salt preparations will require use of standardized and clinically relevant in vitro assay systems and in vivo animal models for testing, as well as development of new outcome measures for inflammation and pain pathways in human OA.

Dietary glucosamine under question

Annual sales of glucosamine as a neutraceutical for affecting cartilage in treatment of osteoarthritis are close to a billion dollars, but recent clinical studies have currently raised severe criticism regarding its functional value. Additional doubts can be raised by the knowledge of the well-defined cellular steps in glucosamine formation and production of glycosaminoglycans such as chondroitin. Glucosamine is produced in an activated state from glucose by essentially all cells for incorporation into glycosaminoglycans and glycoproteins, and there have been no reports of any deficiencies in its production under any conditions. Nevertheless, many investigations of glucosamine, using cells or tissues, have claimed effects on cartilage and chondroitin sulfate. The significance of these studies is questionable since they have invariably been with concentrations that were 10- to 1000-fold higher than has been found in human serum or plasma after glucosamine ingestion. Experiments with cells or tissues using glucosamine in the low concentrations found after ingestion need to be examined before any conclusions are drawn concerning its direct action on cartilage and its potential for modifying osteoarthritis.

The relationship between chondroprotective and antiinflammatory effects of Withania somnifera root and glucosamine sulphate on human osteoarthritic cartilage in vitro

Using a validated explant model of in vitro cartilage damage, the effects of aqueous extracts of Withania somnifera (Ashwagandha) root and glucosamine sulphate (GlcS) were tested on the levels of nitric oxide (NO) and glycosaminoglycans (GAGs) secreted by knee cartilage from chronic osteoarthritis (OA) patients. W. somnifera extracts significantly decreased NO release by explants from one subset of patients (antiinflammatory response) and significantly increased levels of NO and GAGs released by explants from the second subset ('non-responders'). This is the first study showing direct, statistically significant, antiinflammatory effects of W. somnifera on human OA cartilage. It also confirmed that glucosamine sulphate exhibited statistically significant, antiinflammatory and chondroprotective activities in human OA cartilage. However, these beneficial effects of GlcS were observed in cartilage explants from 50% of patients tested ('responders'). In contrast, glucosamine significantly increased secretion of NO but not GAGs in explants from the second subset of OA patients ('non-responders'). Cartilage explants from the 11 OA patients gave differential responses to both drugs. Patient samples which responded to the antiinflammatory effects of W. somnifera did not always give a similar response to glucosamine, and vice versa. Thus, this in vitro model of human cartilage damage provides qualitative and statistically significant, quantitative pre-clinical data on antiinflammatory and chondroprotective activities of antiarthritic drugs.

Yeast as a model system for identification of metabolic targets of a 'glucosamine complex' used as a therapeutic agent of osteoarthritis

This manuscript describes the effect of a glucosamine complex and its different constituents on the metabolism of yeast cells. Indeed, the yeast model biosystem offers important advantages in the understanding of basic cellular and molecular processes. For example, the possibility to differentiate aerobic and anaerobic metabolism allows the measurement of glycolysis and mitochondria importance in the control of energetic metabolism and stress-responsive. Yeast growth and division can be controlled efficiently and effectively by adjusting environmental conditions that mimic some aspect of those experienced by chondrocytes in an osteoarthritic milieu, such as low oxygen and nutriment availabilities, high oxidative stress, etc. The glucosamine complex or some of its components (glucosamine sulphate, MSM, Ribes nigrum and silicon) enhanced cellular proliferation and CO(2) production of yeast cells cultured under severe conditions. In addition, it allows a larger output of protons from the cells into the medium. Glucosamine complex supplementation also boosted cellular resistance to stresses such as heat shock, H(2)O(2)-induced peroxidation and ethanol. The beneficial effects of the complex were primarily due to R. nigrum and to glucosamine sulphate components. The protective effect of the glucosamine complex can be explained by an increase of cellular energy level through intensification of mitochondrial functionality and intracellular machinery (anaerobic glycolysis). An additional effect on protein kinase activation is not unlikely.

Glucosamine: an ingredient with skin and other benefits

Both glucosamine and its derivative N-acetyl glucosamine are amino-monosaccharides that serve key biochemical functions on their own and as substrate precursors for the biosynthesis of polymers such as glycosaminoglycans (e.g., hyaluronic acid) and for the production of proteoglycans. Glucosamine has an excellent safety profile and has been shown to provide benefits in several clinical disorders. Glucosamine compounds have been reported to have several beneficial effects on the skin or skin cells. Because of its stimulation of hyaluronic acid synthesis, glucosamine has been shown to accelerate wound healing, improve skin hydration, and decrease wrinkles. In addition, as an inhibitor of tyrosinase activation, it inhibits melanin production and is useful in treatment of disorders of hyperpigmentation. Mechanistically, glucosamine also has both anti-inflammatory and chondroprotective effects. Clinical trials have shown benefit in using oral glucosamine supplementation to improve symptoms and slow the progression of osteoarthritis in humans. Glucosamine has also been used to prevent and treat osteoarthritis in animals. Based on other observations, glucosamine has been suggested for additional clinical uses, including treatment of inflammatory bowel disease, migraine headaches, and viral infections. The current clinical uses for topical and oral glucosamine compounds and the mechanistic rationale for these uses are reviewed here.

Glucosamine prevents in vitro collagen degradation in chondrocytes by inhibiting advanced lipoxidation reactions and protein oxidation

Osteoarthritis (OA) affects a large segment of the aging population and is a major cause of pain and disability. At present, there is no specific treatment available to prevent or retard the cartilage destruction that occurs in OA. Recently, glucosamine sulfate has received attention as a putative agent that may retard cartilage degradation in OA. The precise mechanism of action of glucosamine is not known. We investigated the effect of glucosamine in an in vitro model of cartilage collagen degradation in which collagen degradation induced by activated chondrocytes is mediated by lipid peroxidation reaction. Lipid peroxidation in chondrocytes was measured by conjugated diene formation. Protein oxidation and aldehydic adduct formation were studied by immunoblot assays. Antioxidant effect of glucosamine was also tested on malondialdehyde (thiobarbituric acid-reactive substances [TBARS]) formation on purified lipoprotein oxidation for comparison. Glucosamine sulfate and glucosamine hydrochloride in millimolar (0.1 to 50) concentrations specifically and significantly inhibited collagen degradation induced by calcium ionophore-activated chondrocytes. Glucosamine hydrochloride did not inhibit lipid peroxidation reaction in either activated chondrocytes or in copper-induced oxidation of purified lipoproteins as measured by conjugated diene formation. Glucosamine hydrochloride, in a dose-dependent manner, inhibited malondialdehyde (TBARS) formation by oxidized lipoproteins. Moreover, we show that glucosamine hydrochloride prevents lipoprotein protein oxidation and inhibits malondialdehyde adduct formation in chondrocyte cell matrix, suggesting that it inhibits advanced lipoxidation reactions. Together, the data suggest that the mechanism of decreasing collagen degradation in this in vitro model system by glucosamine may be mediated by the inhibition of advanced lipoxidation reaction, preventing the oxidation and loss of collagen matrix from labeled chondrocyte matrix. Further studies are needed to relate these in vitro findings to the retardation of cartilage degradation reported in OA trials investigating glucosamine.

Glucosamine reduces anabolic as well as catabolic processes in bovine chondrocytes cultured in alginate

OBJECTIVE

To investigate the working mechanism of glucosamine (GlcN) by studying the effect of different GlcN derivatives on bovine chondrocytes in alginate beads under anabolic and catabolic culture conditions.

METHODS

Bovine chondrocytes seeded in alginate beads were treated with different concentrations of glucosamine-sulfate (GlcN-S), glucosamine-hydrochloride (GlcN-HCl) or N-acetyl-glucosamine (GlcN-Ac). Culture conditions were anabolic, 3 day pre-culture followed by 14 days' treatment; catabolic, extracellular matrix (ECM) breakdown induced by 10ng/ml interleukin-1beta (IL-1beta); or a situation with balance between ECM breakdown and synthesis, 24 days' pre-culture followed by 14 days' treatment. The outcome measurements were total glycosaminoglycan (GAG) and DNA content per bead.

RESULTS

In the situation with balance between ECM breakdown and synthesis, GlcN-Ac had a small stimulatory effect on total GAG content. GlcN-S and GlcN-HCl had no effect. Under anabolic condition 5mM GlcN-S and GlcN-HCl significantly reduced total GAG content. GlcN-Ac did not show this effect. IL-1beta induced catabolic effects were prevented by adding 5mM GlcN-HCl. Interference of GlcN with glucose (Gluc) was demonstrated by adding extra Gluc to the medium in the anabolic culture conditions. Increasing extracellular Gluc concentrations diminished the effect of GlcN.

CONCLUSION

GlcN-S and GlcN-HCl, but not GlcN-Ac, reduce anabolic and catabolic processes. For anabolic processes this was demonstrated by decreased ECM synthesis, for catabolic processes by protection against IL-1beta mediated ECM breakdown. This might be due to interference of GlcN with Gluc utilization. We suggest that the claimed structure modifying effects of GlcN are more likely based on protection against ECM degradation than new ECM production.

Sulfated glucosamine inhibits oxidation of biomolecules in cells via a mechanism involving intracellular free radical scavenging

Although, several effects of glucosamine and its sulfated form (sulfated glucosamine) have been proposed for the suppression of osteoarthritis, their exact mechanisms have not been completely elucidated. This study explains the novel possibility of involvement of sulfated glucosamine in improving cellular antioxidant potential and thereby controlling oxidative damage that could be effective for its therapeutic potential in osteoarthritis. Treatment with sulfated glucosamine to human chondrocytes and macrophages inhibited radical simulated oxidation of membrane lipids, proteins and DNA in a dose-dependent manner. Moreover, detection of reactive oxygen species by electron spin resonance (ESR) spectroscopy and 2',7'-dichlorodihydrofluororescein diacetate (DCFH-DA) fluorescence probe clearly confirmed effective radical scavenging potential of sulfated glucosamine in cellular and non-cellular systems. More importantly, NF-kappaB reporter gene assay and western blot analysis revealed that sulfated glucosamine inhibits radical mediated expression and activation of nuclear factor kappaB (NF-kappaB) proteins (transcription factor involves in expression of a number of genes related to osteoarthritis). Further, sulfated glucosamine enhanced reduced glutathione (GSH) level in oxidatively stressed human chondrocytes improving cellular redox balance. In conclusion, it is suggested that potential effects of sulfated glucosamine in controlling osteoarthritis might be partly via mechanisms involving direct scavenging of cellular radical species and alteration of oxidation mediated destructive events.

[Do disease modifying drugs exist for osteoarthritis]

The osteoarthritis is a disease with high epidemiological, social, and economic impact in health systems. Its treatment has been focused on diminishing pain and inflammation joint; in last years there has appeared on the market a series of drugs that, in studies in vitro show mechanisms of action that might have a modifying effect of disease, since they diminish the proinflammatory cytokines and metalloproteinases involved in degradation of cartilage matrix and it have effect in anti-apoptotics mechanisms in chondrocyte. Clinical studies have showed efficacy against pain and improving joint function; some studies have showed that there is not loss of joint space evaluated by conventional x-ray with longitudinal follow-up of patients. We describe new in vitro action mechanisms of theses new drugs and the clinical evidence of its efficacy in symptoms and potentially modifying effect of the natural history of osteoarthritis.

Glucosamine HCl alters production of inflammatory mediators by rat intervertebral disc cells in vitro

BACKGROUND CONTEXT

Studies on cartilage have shown anti-inflammatory effects of glucosamine related to inhibition of inflammatory mediators. Intradiscal injection of glucosamine has been proposed as a treatment for chronic discogenic low back pain. However, there have been no studies of the direct effects of glucosamine on disc cells.

PURPOSE

To determine the effects of glucosamine HCl on pro-inflammatory mediator production by intervertebral disc cells.

STUDY DESIGN

An in vitro, experimental study of interleukin-1 (IL-1) stimulated rat intervertebral disc cells treated with and without glucosamine HCl.

METHODS

Rat annulus and nucleus cells were cultured in alginate beads and exposed to IL-1a (10 ng/mL)+glucosamine HCl (4.5 mg/mL), IL-1 alone, or neither for 4 and 7 days. Cell viability and IL-6, tumor necrosis factor alpha (TNF-alpha), prostaglandin E(2) (PGE(2)), and NO levels in the medium were quantified and compared across treatments.

RESULTS

Annulus cells, 7 days: Glucosamine completely inhibited IL-6 and TNF-alpha, increased NO (by 75%), and reduced viability (by 89%) compared with IL-1 alone. Nucleus cells, 7 days: Glucosamine reduced IL-6 (by 89%), PGE(2) (91%), and NO (90%) with no effect to viability.

CONCLUSIONS

Glucosamine inhibits inflammatory mediator production by IL-1 stimulated disc cells, but also adversely affects the viability of rat annulus cells. The response is cell-type dependent, illustrated by differences for annulus and nucleus cells.

Synovial and plasma glucosamine concentrations in osteoarthritic patients following oral crystalline glucosamine sulphate at therapeutic dose

OBJECTIVE

We investigated the synovial and plasma glucosamine concentrations in osteoarthritic patients following oral administration of crystalline glucosamine sulphate at the therapeutic dose of 1500mg once-a-day for 14 days.

DESIGN

Twelve osteoarthritic patients (six males and six females) received 14 consecutive once-daily oral administrations of crystalline glucosamine sulphate soluble powder (1500mg), in an open fashion. Plasma and synovial fluid were collected simultaneously from the same patient, at baseline and, at steady state (3h after the last dose). Glucosamine was determined in plasma and synovial fluid by liquid chromatography-tandem mass spectrometry.

RESULTS

Median endogenous glucosamine concentrations in plasma and synovial fluid were 52.0ng/ml (0.29microM) and 36.5ng/ml (0.21microM), respectively (P=0.001), and varied substantially among patients (41-121ng/ml and <10-67ng/ml, respectively). Three hours after the last dose, glucosamine concentrations resulted increased from baseline in all patients with median increases of 20.5 and 21.5 folds in plasma and synovial fluid, respectively, the difference being not statistically significant (P=0.11). In plasma, the median post-treatment value was 1282ng/ml (7.17microM) and ranged from 600 to 4061ng/ml (3.35-22.7microM). The median post-treatment synovial glucosamine concentration was 777ng/ml (4.34microM), i.e., significantly lower than in plasma (P=0.001), and ranged from 577 to 3248ng/ml (3.22-18.1microM). Plasma and synovial glucosamine concentrations were highly correlated and were in the 10microM range.

CONCLUSIONS

Glucosamine is bioavailable both systemically and at the site of action (the joint) after oral administration of crystalline glucosamine sulphate in ostaeoarthritis patients. Steady state glucosamine concentrations in plasma and synovial fluid were correlated and in line with those effective in selected in vitro studies.

Effects of glucosamine sulfate on intracellular UDP-hexosamine and UDP-glucuronic acid levels in bovine primary chondrocytes

OBJECTIVE

To analyze the effects of exogenously added glucose (Glc), glucosamine (GlcN) and glucosamine sulfate (GS) on the intracellular UDP-hexoses (UDP-Hex), UDP-N-acetylhexosamines (UDP-HexN) and UDP-glucuronic acid (UDP-GlcA) levels in bovine primary chondrocytes.

METHODS

Chondrocytes were incubated with different concentrations of Glc, GlcN and GS either in high- or low-glucose DMEM for up to 120min to analyze the intracellular levels of UDP-Hex, UDP-GlcA and UDP-HexN by a reversed-phase high-performance liquid chromatography-electrospray ionization mass spectrometry analysis. Glycosaminoglycan (GAG) synthesis rate and aggrecan mRNA expression levels were quantified using (35)S-sulfate incorporation assay and quantitative real-time RT-PCR, respectively. The cells were cultivated for 2 days or 8 days before UDP-sugar analysis.

RESULTS

Levels of UDP-HexN and UDP-GlcA were unchanged at 10microM concentration of GS in low-glucose DMEM, while addition of 1mM GlcN or GS in low-glucose DMEM for 10min increased UDP-HexN level. The highest intracellular level of UDP-HexN was reached at 30min after addition of 1mM GS to the cells. The intracellular contents of UDP-HexN and UDP-GlcA related to UDP-Hex were higher after prolonged cultivation of chondrocytes for 8 days compared with 2-day-old cultures. Aggrecan mRNA expression and GAG synthesis remained at control level after the cells were treated with 10, 100microM or 1mM of GS for 24h.

CONCLUSION

Physiologically relevant level of GS could not increase the intracellular UDP-HexN and UDP-GlcA levels in bovine primary chondrocyte, while longer-time culture itself appeared to increase the intracellular UDP-HexN and UDP-GlcA levels.

Glucosamine sulfate inhibits proinflammatory cytokine-induced icam-1 production in human conjunctival cells in vitro

PURPOSE

We investigated whether glucosamine sulfate modulates the production of ICAM-1 induced by proinflammatory cytokines and whether glucosamine sulfate inhibits leukocyte adhesion to a monolayer of human conjunctival epithelial cells stimulated with proinflammatory cytokines.

METHODS

We used flow cytometry and either primary cultured human conjunctival cells or the Chang conjunctival cell model to determine the effects of glucosamine sulfate on the production of ICAM-1 in response to tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, interleukin (IL)-1beta, IL-6, TNF-alpha plus IFN-gamma, or TNF-alpha plus IL-1beta. The effects of glucosamine sulfate on the expression of the ICAM-1 gene, upregulated by various cytokines, were determined by semiquantitative reverse transcription-polymerase chain reaction. The activation and nuclear translocation of the nuclear factors NF-kappaB and STAT1 were evaluated by the transient transfection of reporter gene systems and immunocytochemistry. The influence of glucosamine-sulfate-modulated ICAM-1 on neutrophil adhesion was demonstrated in a model that measures the adherence of conjunctival cells and neutrophils.

RESULTS

TNF-alpha, IFN-gamma, and IL-1beta significantly increased the production of ICAM-1 by both primary cultured human conjunctival cells and Chang conjunctival cells. Glucosamine sulfate effectively downregulated the production of ICAM-1 induced by TNF-alpha, IFN-gamma, IL-1beta, TNF-alpha plus IFN-gamma, or TNF-alpha plus IL-1beta. This downregulation occurred through the interferon-stimulated response element, IFN-gamma activation sequence, and binding sequence of NF-kappaB at the mRNA and protein levels. Glucosamine sulfate further inhibited the nuclear translocation of p65 protein in TNF-alpha- and IL-1beta-stimulated Chang conjunctival cells and phosphorylated STAT1 in IFN-gamma-stimulated Chang conjunctival cells. Glucosamine sulfate also significantly reduced the number of neutrophils adhering to a conjunctival monolayer in response to TNF-alpha, IFN-gamma, or IL-1beta.

CONCLUSIONS

Our results suggest that glucosamine sulfate inhibits ICAM-1 production in conjunctival epithelial cells in vitro. Therefore, glucosamine sulfate might be valuable in the treatment of inflammatory ocular-surface conditions.

Exogenous glucosamine globally protects chondrocytes from the arthritogenic effects of IL-1beta

The effects of exogenous glucosamine on the biology of articular chondrocytes were determined by examining global transcription patterns under normal culture conditions and following challenge with IL-1β. Chondrocytes isolated from the cartilage of rats were cultured in several flasks either alone or in the presence of 20 mM glucosamine. Six hours later, one-half of the cultures of each group were challenged with 10 ng/ml IL-1β. Fourteen hours after this challenge, RNA was extracted from each culture individually and used to probe microarray chips corresponding to the entire rat genome. Glucosamine alone had no observable stimulatory effect on the transcription of primary cartilage matrix genes, such as aggrecan, collagen type II, or genes involved in glycosaminoglycan synthesis; however, glucosamine proved to be a potent, broad-spectrum inhibitor of IL-1β. Of the 2,813 genes whose transcription was altered by IL-1β stimulation (P < 0.0001), glucosamine significantly blocked the response in 2,055 (~73%). Glucosamine fully protected the chondrocytes from IL-1-induced expression of inflammatory cytokines, chemokines, and growth factors as well as proteins involved in prostaglandin E₂ and nitric oxide synthesis. It also blocked the IL-1-induced expression of matrix-specific proteases such as MMP-3, MMP-9, MMP-10, MMP-12, and ADAMTS-1. The concentrations of IL-1 and glucosamine used in these assays were supraphysiological and were not representative of the arthritic joint following oral consumption of glucosamine. They suggest, however, that the potential benefit of glucosamine in osteoarthritis is not related to cartilage matrix biosynthesis, but is more probably related to its ability to globally inhibit the deleterious effects of IL-1β signaling. These results suggest that glucosamine, if administered effectively, may indeed have anti-arthritic properties, but primarily as an anti-inflammatory agent.

Rehabilitation of articular lesions in the athlete's knee

Articular cartilage lesions of the knee joint are common in patients of varying ages. Some articular cartilage lesions are focal lesions located on one aspect of the tibiofemoral or patellofemoral joint. Other lesions can be extremely large or involve multiple compartments of the knee joint and these are often referred to as osteoarthritis. There are numerous potential causes for the development of articular cartilage lesions: joint injury (trauma), biomechanics, genetics, activities, and biochemistry. Numerous factors also contribute to symptomatic episodes resulting from lesions to the articular cartilage: activities (sports and work), joint alignment, joint laxity, muscular weakness, genetics, dietary intake, and body mass index. Athletes appear to be more susceptible to developing articular cartilage lesions than other individuals. This is especially true with specific sports and subsequent to specific types of knee injuries. Injuries to the anterior cruciate ligament and/or menisci may increase the risk of developing an articular cartilage lesion. The treatment for an athletic patient with articular cartilage lesions is often difficult and met with limited success. In this article we will discuss several types of knee articular cartilage injuries such as focal lesions, advanced full-thickness lesions, and bone bruises. We will also discuss the risk factors for developing full-thickness articular cartilage lesions and osteoarthritis, and describe the clinical evaluation and nonoperative treatment strategies for these types of lesions in athletes.

Diacerhein versus glucosamine in a rat model of osteoarthritis

PURPOSE

The purpose of this study was to compare the chondroprotective effect of diacerein and glucosamine regarding degenerative changes and articular stiffness in an experimental model of arthritis.

METHODS

Twenty rats underwent medial meniscectomy on the right knee. Ten animals were given diacerhein, and 10 were given glucosamine, from day 1 to the third month postoperatively, when all of them were killed. Histological and functional analysis of the knees were performed (measurement of maximum extension).

RESULTS

All operated knees showed more limited extension values and more degenerative changes as compared to nonoperated contralateral sides. A comparison of the two drugs showed that the degree of articular stiffness was significantly lower with diacerein, although degenerative changes were similar.

CONCLUSIONS

1) Prophylactic use of diacerein leads to lower degree of articular stiffness when compared to glucosamine; 2) The prophylactic chondroprotective effects of diacerein and glucosamine are histologically similar.

Glucosamine sulfate suppresses the expressions of urokinase plasminogen activator and inhibitor and gelatinases during the early stage of osteoarthritis

BACKGROUND

Glucosamine sulfate may have an ex vivo inhibitory effect on the plasminogen activator (PA)/plasmin system and gelatinases expression during the early development of osteoarthritis (OA).

METHODS

We compared the levels of urokinase-type PA (u-PA), PA inhibitor-1 (PAI-1) and gelatinases (matrix metalloproteinase-2 and -9 [MMP-2 and -9]) in a series of chondral, meniscal, and synovial cultures of early OA after treatment with or without glucosamine sulfate.

RESULTS

Gelatin zymography revealed that glucosamine sulfate could suppress MMP-2 secretion in chondral, meniscal and synovial cultures and also decrease MMP-9 production in synovial and meniscal cultures. ELISA data also showed the suppressive effects of glucosamine sulfate on u-PA and PAI-1 production in synovial cultures at 48 h.

CONCLUSIONS

Our data suggest that one of the therapeutic effects of glucosamine sulfate is to down-regulate the expressions of u-PA, PAI-1, MMP-2 and MMP-9 that underlie the destruction of articular cartilage in the early stage of OA, and therefore to delay the joint failure.

Oral treatment options for degenerative joint disease--presence and future

Alleviation of pain and inhibition of inflammation are the primary goals of pharmacotherapy of osteoarthritis (OA). These therapeutic goals can almost always be accomplished by the use of analgesics and nonsteroidal anti-inflammatory drugs (NSAID). One of the main problems of NSAIDs is their gastrointestinal toxicity, for which a prophylactic medication should be considered particularly amongst risk groups. Recent studies have shown that COX-2-selective and maybe also non-selective NSAIDs increase the cardiovascular risk so that their application is getting now drastically restricted. Pharmacological results published until now suggest that a clinically relevant minor analgesic and/or anti-inflammatory effect can be attained with the use of some of the SYmptomatic Slow Acting Drugs in OA (SYSADOAs). However, no clinical studies exist, which can positively confirm prevention, slowing down or reversal of any advanced joint cartilage destruction by any individual medication. Disease modifying therapy is still in its infancy; discovery and development of novel therapeutic targets and agents are an extremely difficult task, currently challenging many pharmaceutical companies and academic institutions.

Medical treatment of osteoarthritis in the horse - a review

The medical treatment of osteoarthritis (OA) in the horse is one of the most utilized therapeutic regimens in the equine practice. It is important to understand the anatomy of synovial joints and the pathophysiology of the disease process to treat OA adequately. Once a thorough understanding of the disease process is comprehended the proper combination of systemic nonsteroidal anti-inflammatory drugs (NSAIDs), intraarticular steroids, viscosupplementation and chondroprotectants can be used to treat the disease and inhibit further progression of degenerative changes to the cartilage surface. The equine practitioner is faced with many choices for controlling inflammation in OA. This review presents the background and appropriate uses of various NSAIDs such as phenylbutazone, flunixin meglumine, ketoprofen, naproxen, and carprofen as well as their associated toxicities. Various steroid formulations exist for intraarticular (IA) administration and much has been learned in the past decade regarding correct dosage, frequency of administrations, indications and toxicity. This review presents IA steroids and their indications in addition to various chondroprotective drugs that also exist to control inflammation and provide viscosupplementation. Data are also given on disease modifying OA drugs such as glucosamine and chondroitin sulphate that have more recently become available to the equine practitioner.

The lack of effect of glucosamine sulphate on aggrecan mRNA expression and 35S-sulphate incorporation in bovine primary chondrocytes

Glucosamine and glucosamine sulphate have been promoted as a disease-modifying agent to improve the clinical symptoms of osteoarthritis. The precise mechanism of the action of the suggested positive effect of glucosamine or glucosamine sulphate on cartilage proteoglycans is not known, since the level of glucosamine in plasma remains very low after oral administration of glucosamine sulphate. We examined whether exogenous hexosamines or their sulphated forms would increase steady-state levels of aggrecan and hyaluronan synthase (HAS) or glycosaminoglycan synthesis using Northern blot and (35)S-sulphate incorporation analyses. Total RNA was extracted from bovine primary chondrocytes which were cultured either in 1 mM concentration of glucosamine, galactosamine, mannosamine, glucosamine 3-sulphate, glucosamine 6-sulphate or galactosamine 6-sulphate for 0, 4, 8 and 24 h, or in three different concentrations (control, 100 microM and 1 mM) of glucosamine sulphate salt or glucose for 24 or 72 h. Northern blot assay showed that neither hexosamines nor glucosamine sulphate salt stimulated aggrecan and HAS-2 mRNA expression. Glycosaminoglycan synthesis remained at a control level in the treated cultures, with the exception of mannosamine which inhibited (35)S-sulphate incorporation in low-glucose DMEM treatment. In our culture conditions, hexosamines or their sulphated forms did not increase aggrecan expression or (35)S-sulphate incorporation.

Glucosamine decreases expression of anabolic and catabolic genes in human osteoarthritic cartilage explants

OBJECTIVE

To investigate the effect of glucosamine (GlcN) in a human osteoarthritic explant model on expression of genes involved in anabolic and catabolic activities of chondrocytes.

METHODS

Human osteoarthritic explants, obtained during knee arthroplasty surgery, were pre-cultured (3 days) and treated with glucosamine-hydrochloride (GlcN-HCl) or glucosamine-3-sulphate (GlcN-S) at 0.5mM and 5mM (4 days). RNA was isolated from the explants and real time RT-PCR was performed. Additionally, total matrix metalloproteinase (MMP) activity was measured in culture medium.

RESULTS

Addition of 5mM GlcN led to significant down-regulation of aggrecan (2.65-7.73-fold) and collagen type II (7.75-22.17-fold) gene expression, indicating inhibited anabolic activity. Considering catabolic activities, 5mM GlcN significantly down-regulated aggrecanase-1 and MMP3 and 5mM GlcN-S additionally down-regulated aggrecanase-2 and tissue inhibitor of MMP gene expression significantly. Gene expression was not significantly altered by 0.5mM GlcN. Total MMP activity in culture medium was only significantly reduced after addition of 5mM GlcN-HCl.

CONCLUSION

The effects of GlcN on gene expression in a human osteoarthritic explant model suggest that enzymatic breakdown of the extra-cellular matrix might be reduced by the addition of 5mM GlcN. Additionally, restoration of already damaged cartilage is not to be expected, because gene expression of anabolic genes is also down-regulated. We suggest that chondroprotective properties of GlcN in vivo may be based on inhibiting further degradation due to catabolic activities, rather than on the ability to rebuild cartilage.

Glucosamine oral bioavailability and plasma pharmacokinetics after increasing doses of crystalline glucosamine sulfate in man

OBJECTIVE

Pharmacokinetic data on glucosamine are scant, limiting the understanding of glucosamine sulfate mechanism of action in support of its treatment effects in osteoarthritis. This study investigated the oral pharmacokinetics and dose-proportionality of glucosamine after administration of the patented crystalline glucosamine sulfate in man.

METHODS

Twelve healthy volunteers received three consecutive once-daily oral administrations of glucosamine sulfate soluble powder at the doses of 750, 1,500, and 3,000 mg, in an open, randomised, cross-over fashion. Glucosamine was determined in plasma collected up to 48 h after the last dose by a validated Liquid Chromatography method with Mass Spectrometry detection. Pharmacokinetic parameters were calculated at steady state.

RESULTS

Endogenous plasma levels of glucosamine were detected (10.4-204 ng/ml, with low intra-subject variability). Glucosamine was rapidly absorbed after oral administration and its pharmacokinetics were linear in the dose range 750-1,500 mg, but not at 3,000 mg, where the plasma concentration-time profiles were less than expected based on dose-proportionality. Plasma levels increased over 30-folds from baseline and peaked at about 10 microM with the standard 1,500 mg once-daily dosage. Glucosamine distributed to extravascular compartments and its plasma concentrations were still above baseline up to the last collection time. Glucosamine elimination half-life was only tentatively estimated to average 15 h.

CONCLUSIONS

Glucosamine is bioavailable after oral administration of crystalline glucosamine sulfate, persists in circulation, and its pharmacokinetics support once-daily dosage. Steady state peak concentrations at the therapeutic dose of 1,500 mg were in line with those found to be effective in selected in vitro mechanistic studies. This is the only glucosamine formulation for which pharmacokinetic, efficacy and safety data are now available.

The Use of Nutraceuticals for Osteoarthritis in Horses

In horses, lameness is often attributable to some degree of osteoarthritis (OA), a complex disease process that is highlighted by eventual degradation of articular cartilage. Conventional therapies for OA in horses are designed to relieve pain and discomfort and often include pharmacologic intervention with nonsteroidal anti-inflammatory drugs or intra-articular steroids. Oral administration of nutraceutical products to the horse is common and easy and is perceived to be a benign treatment for OA in horses. The main goal for use of nutraceuticals is to use them in OA cases to attempt to lower the dose of other drugs that are more problematic while potentially preventing further degradation (disease or structure modifying). This article attempts to define a nutraceutical, identifies areas that need to be considered when these products are used, and describes the known scientific effects of the most common compounds contained in currently available equine nutraceuticals.

Chondroprotective drugs in degenerative joint diseases

Catabolic cytokine and anabolic growth factor pathways control destruction and repair in osteoarthritis (OA). A unidirectional TNF-alpha/IL-1-driven cytokine cascade disturbs the homeostasis of the extracellular matrix of articular cartilage in OA. Although chondrocytes in OA cartilage overexpress anabolic insulin-like growth factor (IGF) and its specific receptor (IGFRI) autocrine TNF-alpha released by apoptotic articular cartilage cells sets off an auto/paracrine IL-1-driven cascade that overrules the growth factor activities that sustain repair in degenerative joint disease. Chondroprotection with reappearance of a joint space that had disappeared has been documented unmistakably in peripheral joints of patients suffering from spondyloarthropathy when treated with TNF-alpha-blocking agents that repressed the unidirectional TNF-alpha/IL-1-driven cytokine cascade. A series of connective tissue structure-modifying agents (CTSMAs) that directly affect IL-1 synthesis and release in vitro and down-modulate downstream IL-1 features, e.g. collagenase, proteoglycanase and matrix metalloproteinase activities, the expression of inducible nitric oxide synthase, the increased release of nitric oxide, and the secretion of prostaglandin E(2), IL-6 and IL-8, have been shown to possess disease-modifying OA drug (DMOAD) activities in experimental models of OA and in human subjects with finger joint and knee OA. Examples are corticosteroids, some sulphated polysaccharides, chemically modified tetracyclines, diacetylrhein/rhein, glucosamine and avocado/soybean unsaponifiables.