Articular cartilage pharmacology: I. In vitro studies on glucosamine and non steroidal antiinflammatory drugs

Protective effect of glucosamine and risedronate (alone or in combination) against osteoarthritic changes in rat experimental model of immobilized knee

This study is aiming to investigate the protective effect of glucosamine, risedronate (alone or in combination) on articular cartilage in experimental model of immobilized rat knee. Twenty-five adult male albino rats were divided into five groups (five rats each): control group, immobilized group, glucosamine-treated group, risedronate-treated group, and group treated by a combination of glucosamine and risedronate. The articular cartilage was obtained for histological, immunohistochemical and morphometric studies. The immobilized group showed manifestations of osteoarthritis in the form of significant decrease of articular cartilage thickness with surface erosions, shrunken chondrocytes with pyknotic nuclei and marked manifested fall of chondrocyte number. There was manifested reduction of collagen contents of the articular cartilage using Masson trichrome stain. Safranin O–Fast Green revealed low proteoglycan contents. The collagen type II was also declined. The manikin score was 7.8. Risedronate improved this manifestation slightly more than glucosamine, but combination of booth drugs caused significant improvement of the damaged articular cartilage caused by immobilization. Oral administration of glucosamine and risedronate improved the degenerative changes of rat knee articular cartilage that follow immobilization. This improvement was more remarkable when both drugs were used in combination.

Evaluation of the chondroprotective effects of glucosamine and fish collagen peptide on a rabbit ACLT model using serum biomarkers

The aim of this study was to investigate the correlations of severity of osteoarthritis (OA) and serum biomarkers including keratan sulfate (KS), hyaluronic acid (HA) and chondroitin sulfate (CS) 846 epitope. We also investigated the effect of glucosamine and fish collagen peptide (FCP) on OA. OA was induced in 12 rabbits (12 weeks of age) by anterior cruciate ligament transection (ACLT). After the surgery, the rabbits were orally administered FCP (F group), glucosamine (G group) or FCP and glucosamine (FG group) for 4 weeks. The control group was provided water ad libitum (C group). Blood was collected before surgery (pre-ACLT) and before euthanasia (post-ACLT) for serum marker measurement. Biomarker levels were measured by using commercial kits. We evaluated OA severity both macroscopically and histologically. Macroscopic evaluation showed mildly eroded condylar surfaces in the C group. Histological findings were significantly different from the FG and other groups. There were no significant differences between each group at post-ACLT in terms of serum KS, HA and CS 846. Histological assessment and serum biomarker measurements performed at post-ACLT showed a significant correlation between HA concentration and OA severity. Variations in the CS 846 concentration at pre-ACLT and post-ACLT were significantly correlated with OA severity. Administration of glucosamine and FCP had chondroprotective effects in the ACLT model. Serum biomarker concentrations were significantly correlated with cartilage injury. Serum biomarker measurement would be useful for monitoring articular cartilage damage in the clinical setting.

N-acetylglucosamine: production and applications

N-Acetylglucosamine (GlcNAc) is a monosaccharide that usually polymerizes linearly through (1,4)-β-linkages. GlcNAc is the monomeric unit of the polymer chitin, the second most abundant carbohydrate after cellulose. In addition to serving as a component of this homogeneous polysaccharide, GlcNAc is also a basic component of hyaluronic acid and keratin sulfate on the cell surface. In this review, we discuss the industrial production of GlcNAc, using chitin as a substrate, by chemical, enzymatic and biotransformation methods. Also, newly developed methods to obtain GlcNAc using glucose as a substrate in genetically modified microorganisms are introduced. Moreover, GlcNAc has generated interest not only as an underutilized resource but also as a new functional material with high potential in various fields. Here we also take a closer look at the current applications of GlcNAc, and several new and cutting edge approaches in this fascinating area are thoroughly discussed.

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.

Glucosamine and chondroitin for osteoarthritis

Osteoarthritis (OA) is a common, chronic disease that most frequently affects the knees and is a major cause of disability in the elderly. It is characterized by progressive cartilage loss, accompanied by secondary changes such as osteophyte formation and calcium deposition. Inflammatory processes are also involved, leading to stiffness and pain, for which patients seek treatment. Conventional treatment includes analgesics or non-steroidal anti-inflammatory drugs, however life-style changes should also be recommended, such as weight reduction and specific exercises. Glucosamine and chondroitin, classed as over-the-counter supplements or nutraceuticals, are regularly self-administered by patients with OA. Both agents are produced endogenously in the human body and are essential components of cartilage. This review discusses the evidence that supports the use of these agents either alone or in combination for pain relief and as disease-modifying agents in OA.

Glucosamine increases hyaluronic acid production in human osteoarthritic synovium explants

Background

Glucosamine (GlcN) used by patients with osteoarthritis was demonstrated to reduce pain, but the working mechanism is still not clear. Viscosupplementation with hyaluronic acid (HA) is also described to reduce pain in osteoarthritis. The synthesis of HA requires GlcN as one of its main building blocks. We therefore hypothesized that addition of GlcN might increase HA production by synovium tissue.

Methods

Human osteoarthritic synovium explants were obtained at total knee surgery and pre-cultured for 1 day. The experimental conditions consisted of a 2 days continuation of the culture with addition of N-Acetyl-glucosamine (GlcN-Ac; 5 mM), glucosamine-hydrochloride (GlcN-HCl; 0.5 and 5 mM), glucose (Gluc; 0.5 and 5 mM). Hereafter HA production was measured in culture medium supernatant using an enzyme-linked binding protein assay. Real time RT-PCR was performed for hyaluronic acid synthase (HAS) 1, 2 and 3 on RNA isolated from the explants.

Results

0.5 mM and 5 mM GlcN-HCl significantly increased HA production compared to control (approximately 2 – 4-fold), whereas GlcN-Ac had no significant effect. Addition of 5 mM Gluc also increased HA production (approximately 2-fold), but 0.5 mM Gluc did not. Gene expression of the HA forming enzymes HAS 1, 2 and 3 was not altered by the addition of GlcN or Gluc.

Conclusion

Our data suggest that exogenous GlcN can increase HA production by synovium tissue and is more effective at lower concentrations than Gluc. This might indicate that GlcN exerts its potential analgesic properties through stimulation of synovial HA production.

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.

An optimized reverse-phase high performance liquid chromatographic method for evaluating percutaneous absorption of glucosamine hydrochloride

A relatively simple, selective, precise and accurate high performance liquid chromatography (HPLC) method based on a reaction of phenylisothiocyanate (PITC) with glucosamine (GL) in alkaline media was developed and validated to determine glucosamine hydrochloride permeating through human skin in vitro. It is usually problematic to develop an accurate assay for chemicals traversing skin because the excellent barrier properties of the tissue ensure that only low amounts of the material pass through the membrane and skin components may leach out of the tissue to interfere with the analysis. In addition, in the case of glucosamine hydrochloride, chemical instability adds further complexity to assay development. The assay, utilising the PITC-GL reaction was refined by optimizing the reaction temperature, reaction time and PITC concentration. The reaction produces a phenylthiocarbamyl-glucosamine (PTC-GL) adduct which was separated on a reverse-phase (RP) column packed with 5 microm ODS (C18) Hypersil particles using a diode array detector (DAD) at 245 nm. The mobile phase was methanol-water-glacial acetic acid (10:89.96:0.04 v/v/v, pH 3.5) delivered to the column at 1 ml min-1 and the column temperature was maintained at 30 degrees C. Galactosamine hydrochloride (Gal-HCl) was used as an internal standard. Using a saturated aqueous solution of glucosamine hydrochloride, in vitro permeation studies were performed at 32+/-1 degrees C over 48 h using human epidermal membranes prepared by a heat separation method and mounted in Franz-type diffusion cells with a diffusional area 2.15+/-0.1 cm2. The optimum derivatisation reaction conditions for reaction temperature, reaction time and PITC concentration were found to be 80 degrees C, 30 min and 1% v/v, respectively. PTC-Gal and GL adducts eluted at 8.9 and 9.7 min, respectively. The detector response was found to be linear in the concentration range 0-1000 microg ml-1. The assay was robust with intra- and inter-day precisions (described as a percentage of relative standard deviation, %R.S.D.) <12. Intra- and inter-day accuracy (as a percentage of the relative error, %RE) was <or=-5.60 and <or=-8.00, respectively. Using this assay, it was found that GL-HCl permeates through human skin with a flux 1.497+/-0.42 microg cm-2 h-1, a permeability coefficient of 5.66+/-1.6x10(-6) cm h-1 and with a lag time of 10.9+/-4.6 h.

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 therapy for treating osteoarthritis

BACKGROUND

Osteoarthritis (OA) is the most common form of arthritis, and it is often associated with significant disability and an impaired quality of life.

OBJECTIVES

To review all randomized controlled trials (RCTs) evaluating the effectiveness and toxicity of glucosamine in OA.

SEARCH STRATEGY

We searched MEDLINE, PREMEDLINE, EMBASE, AMED, ACP Journal Club, DARE, CDSR, and the CCTR. We also wrote letters to content experts, and hand searched reference lists of identified RCTs and pertinent review articles. All searches were updated in January 2005.

SELECTION CRITERIA

Relevant studies met the following criteria: 1) RCTs evaluating the effectiveness and safety of glucosamine in OA, 2) Both placebo controlled and comparative studies were eligible, 3) Both single blinded and double blinded studies were eligible.

DATA COLLECTION AND ANALYSIS

Data abstraction was performed independently by two investigators and the results were compared for degree of agreement. Gotzsche's method and a validated tool (Jadad 1996) were used to score the quality of the RCTs. Continuous outcome measures were pooled using standardized mean differences (SMD) as the measure of effect size. Dichotomous outcome measures were pooled using relative risk ratios (RR).

MAIN RESULTS

Analysis restricted to eight studies with adequate allocation concealment failed to show benefit of glucosamine for pain and WOMAC function. Collectively, the 20 analyzed RCTs found glucosamine favoured placebo with a 28% (change from baseline) improvement in pain (SMD -0.61, 95% CI -0.95, -0.28) and a 21% (change from baseline) improvement in function using the Lequesne index (SMD -0.51 95% CI -0.96, -0.05). However, the results are not uniformly positive, and the reasons for this remain unexplained. WOMAC pain, function and stiffness outcomes did not reach statistical significance. In the 10 RCTs in which the Rotta preparation of glucosamine was compared to placebo, glucosamine was found to be superior for pain (SMD -1.31, 95% CI -1.99, -0.64) and function using the Lequesne index (SMD -0.51, 95% CI -0.96, -0.05). Pooled results for pain (SMD -0.15, 95% CI -0.35, 0.05) and function using the WOMAC index (SMD 0.03, 95% CI -0.18, 0.25) in those RCTs in which a non-Rotta preparation of glucosamine was compared to placebo did not reach statistical significance. In the four RCTs in which the Rotta preparation of glucosamine was compared to an NSAID, glucosamine was superior in two, and equivalent in two. Two RCTs using the Rotta preparation showed that glucosamine was able to slow radiological progression of OA of the knee over a three year period (SMD 0.24, 95% CI 0.04, 0.43). Glucosamine was as safe as placebo in terms of the number of subjects reporting adverse reactions (RR=0.97, 95% CI, 0.88, 1.08).

AUTHORS' CONCLUSIONS

This update includes 20 studies with 2570 patients. Pooled results from studies using a non-Rotta preparation or adequate allocation concealment failed to show benefit in pain and WOMAC function while those studies evaluating the Rotta preparation show that glucosamine was superior to placebo in the treatment of pain and functional impairment resulting from symptomatic OA. WOMAC outcomes of pain, stiffness and function did not show a superiority of glucosamine over placebo for both Rotta and non-Rotta preparations of glucosamine. Glucosamine was as safe as placebo.

Subchronic toxicity study of dietary N-acetylglucosamine in F344 rats

A subchronic toxicity study of N-acetylglucosamine (GlcNAc), a monomeric form of chitin, was conducted in groups of 10 male and 10 female F344 rats fed pelleted diets containing 0, 0.625, 1.25, 2.5 or 5% concentrations for 13 weeks. All animals survived until the end of the experiment. Slight, non-significant increase in body weights was observed in males receiving 0.625, 1.25 or 2.5% from week 4 until the end of the experiment, when significant elevation was found for the males receiving 0.625, 1.25 or 2.5% at the terminal sacrifice to result in decreased relative weights of many organs in these cases. However, there were no obvious indications of toxicity in any group receiving GlcNAc in terms of clinical signs, food intake, hematology, serum biochemistry, and histopathological findings. Thus, it was concluded that orally administered GlcNAc exerts no obvious toxicity to F344 rats at concentrations up to 5% in the diet for 13 weeks. Based on the present toxicity data, > or =5% was determined to be a no-observed-adverse-effect level, translated into 2476 and 2834 mg/kg/day for male and female rats, respectively.

Chondroprotective agents: glucosamine and chondroitin

The near universal finding of the safety of glucosamine and chondroitin combined with some compelling evidence of their efficacy should spur further research into their mechanism of action, optimal dosing, long-term effects on disease modification, and clinical applicability. When recommending a supplement to patients, the clinician should take into account the purity of the ingredients, reputation of the manufacturer, and the molecular weight of chondroitin supplied.

The effect of glucosamine supplementation on people experiencing regular knee pain

OBJECTIVE

The purpose of this study was to examine the effects of oral glucosamine supplementation on the functional ability and degree of pain felt by individuals who had regular knee pain, most likely due to previous articular cartilage damage, and possibly osteoarthritis.

METHODS

Subjects were randomly supplemented with either glucosamine (G) (n=24) or placebo (P) (lactose) (n=22) for 12 weeks at a dose of 2,000 mg per day. Over this period, four testing sessions were conducted, with changes in knee pain and function assessed by clinical and functional tests, (joint line palpation, a 3 metre "duck walk" and a repeated, walking stair climb), two questionnaires (the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Knee Pain Scale (KPS)) and participant subjective evaluations.

RESULTS

The clinical and functional test scores improved with time (main effects: p<0.05, p<0.01) but there were no significant differences between the two groups. The questionnaire results also recorded a significant main effect for time (p<0.05), but the glucosamine group was found to have significantly better KOOS quality of life scores at week eight and 12 (p<0.05), and lower KPS scores (p<0.05) at week eight than the placebo group. On self report evaluations of changes across the 12 week supplementation period, 88% (n=21) of the glucosamine group reported some degree of improvement in their knee pain versus only 17% (n=3) in the placebo group.

CONCLUSIONS

These results suggest that glucosamine supplementation can provide some degree of pain relief and improved function in persons who experience regular knee pain, which may be caused by prior cartilage injury and/or osteoarthritis. The trends in the results also suggest that, at a dosage of 2,000 mg per day, the majority of improvements are present after eight weeks.

High doses of glucosamine-HCl have detrimental effects on bovine articular cartilage explants cultured in vitro

OBJECTIVE

To investigate both the biochemical and the potential morphological changes in bovine cartilage explants following treatment with glucosamine HCl, and to evaluate the capability of glucosamine to counteract the degradation of cartilage induced by catabolic agents such as interleukin-1beta (IL-1beta) and the bacterial lipopolysaccharide (LPS).

DESIGN

Bovine articular cartilage explants were treated with increasing doses of glucosamine HCl (0.25-25mg/ml) in the absence or in the presence of IL-1beta or LPS. The release of matrix proteoglycans in the medium, as well as variations in nitric oxide and lactate production were evaluated by standard assays. Proteoglycan synthesis was determined by incorporation of Na(2)-(35)SO(4). Ultrastructural analysis was performed by transmission electron microscopy.

RESULTS

Increasing doses of glucosamine (2.5, 6.5, 25mg/ml) induced a dose-dependent decrease in proteoglycan synthesis and in lactate production after 24h treatment. The biochemical changes induced by IL1-beta or LPS appeared to be inhibited by 6.5 and 25mg/ml glucosamine. At these concentrations a decrease in cell viability was observed, which reached over 90% at 25mg/ml.

CONCLUSIONS

This study shows that pharmacological doses of glucosamine induce a broad impairment in the metabolic activity of bovine chondrocytes, leading to cell death. The inhibition of the catabolic effects induced by IL1-beta and LPS appears related to glucosamine toxicity. In other experimental models, the same or similar doses of glucosamine have previously been used, without showing any adverse effect. We conclude that, in studying the effects of glucosamine, particular attention should be addressed to the experimental model, the doses and the length of treatment. Published by Elsevier Science Ltd. All rights reserved.

Effect of oral glucosamine on cartilage and meniscus in normal and chymopapain-injected knees of young rabbits

OBJECTIVE

To determine if oral glucosamine (GlcN) improves joint biology after acute damage by a protease.

METHODS

The effect of 8 weeks of dietary GlcN (20 or 100 mg/kg/day) on knee joint cartilage was evaluated in 2.2-kg male NZW rabbits with and without damage introduced by intraarticular injection of chymopapain (CP). Cartilage was evaluated histologically and scored according to the Mankin scale. Analyses of total hydroxyproline and glycosaminoglycan (GAG) contents and reverse transcription-polymerase chain reaction (RT-PCR) analysis of selected genes were performed.

RESULTS

After 8 weeks, there was no effect of GlcN on the GAG content of normal cartilage. Both levels of GlcN treatment significantly increased the sulfated GAG content in the cartilage of the medial femoral condyle in damaged and contralateral knees, but did not change the collagen content. In CP-injected knees, there was still some loss of surface proteoglycan (PG) that was not completely corrected by dietary GlcN. Even after 8 weeks, levels of messenger RNA (mRNA) detected by RT-PCR showed changes indicative of damage and repair, such as elevated type II collagen mRNA, and these levels were not influenced by GlcN treatment. Meniscal GAG content was increased in the contralateral knee of rabbits receiving high-dose GlcN, but was decreased in those receiving no GlcN or low-dose GlcN. Neither diet nor treatment affected the meniscal collagen content.

CONCLUSION

These results suggest that oral GlcN treatment might be useful in a situation where GlcN is limiting, such as where there is a rapid replacement of cartilage PG.

A survey of self-medication practices and perceived effectiveness of glucosamine products among older adults

OBJECTIVES

The purpose of this study was to investigate the decision-making and self-treatment practices of older users of glucosamine products, namely (1) how do older adults decide to use glucosamine products? (2) what influences their choice? (3) how do they manage their glucosamine treatment? and (4) what is their perception of the effectiveness, side effects, and costs of glucosamine products?

DESIGN

A descriptive, exploratory study using a questionnaire survey.

SETTING

Province-wide. Invitations to participate were extended to all people living in a Canadian province who used/had used glucosamine products.

RESULTS

Advice from friends was a major factor in the decision to take glucosamine. Cost was a major factor influencing the type and brand name of the product used. Ninety-two percent managed their own treatment. The majority (88%) used glucosamine regularly; only one-third took the recommended daily dose. Sixty-seven percent perceived the product to be helpful in relieving symptoms.

CONCLUSION

Public education and further research is needed regarding the use of glucosamine products.

N-acetylglucosamine prevents IL-1 beta-mediated activation of human chondrocytes

Glucosamine represents one of the most commonly used drugs to treat osteoarthritis. However, mechanisms of its antiarthritic activities are still poorly understood. The present study identifies a novel mechanism of glucosamine-mediated anti-inflammatory activity. It is shown that both glucosamine and N-acetylglucosamine inhibit IL-1beta- and TNF-alpha-induced NO production in normal human articular chondrocytes. The effect of the sugars on NO production is specific, since several other monosaccharides, including glucose, glucuronic acid, and N-acetylmannosamine, do not express this activity. Furthermore, N-acetylglucosamine polymers, including the dimer and the trimer, also do not affect NO production. The observed suppression of IL-1beta-induced NO production is associated with inhibition of inducible NO synthase mRNA and protein expression. In addition, N-acetylglucosamine also suppresses the production of IL-1beta-induced cyclooxygenase-2 and IL-6. The constitutively expressed cyclooxygenase-1, however, was not affected by the sugar. N-acetylglucosamine-mediated inhibition of the IL-1beta response of human chondrocytes was not associated with the decreased inhibition of the mitogen-activated protein kinases c-Jun N-terminal kinase, extracellular signal-related kinase, and p38, nor with activation of the transcription factor NF-kappaB. In conclusion, these results demonstrate that N-acetylglucosamine expresses a unique range of activities and identifies a novel mechanism for the inhibition of inflammatory processes.

Use of glucosamine and chondroitin sulfate in the management of osteoarthritis

The goals of osteoarthritis therapy are to decrease pain and to maintain or improve joint function. The pharmacologic treatment of this condition has included the use of aspirin, acetaminophen, and nonsteroidal anti-inflammatory drugs. More recently, numerous studies have investigated the potential role of chondroprotective agents in repairing articular cartilage and decelerating the degenerative process. The reports of limited clinical experience with two of these agents, glucosamine and chondroitin sulfate, as well as the accompanying publicity in the popular media, have generated controversy. Advocates of these alternative modalities cite reports of progressive and gradual decline of joint pain and tenderness, improved mobility, sustained improvement after drug withdrawal, and a lack of significant toxicity associated with short-term use of these agents. Critics point out that in the great majority of the relevant clinical trials, sample sizes were small and follow-up was short-term.

Glucosamine therapy for treating osteoarthritis

BACKGROUND

Osteoarthritis (OA) is the most common form of arthritis, and it is often associated with significant disability and an impaired quality of life.

OBJECTIVES

To review all randomized controlled trials (RCTs) evaluating the effectiveness and toxicity of glucosamine in osteoarthritis (OA).

SEARCH STRATEGY

We searched MEDLINE, Embase, and Current Contents up to November 1999, and the Cochrane Controlled Trials Register. We also wrote letters to content experts, and hand searched reference lists of identified RCTs and pertinent review articles.

SELECTION CRITERIA

Relevant studies met the following criteria: 1) RCTs evaluating the effectiveness and safety of glucosamine in OA, 2) Both placebo based and comparative studies were eligible, 3) Both single blinded and double-blinded studies were eligible.

DATA COLLECTION AND ANALYSIS

Data abstraction was performed independently by two investigators and the results were compared for degree of agreement. Gotzsche's method and a validated tool (Jadad 1995) were used to score the quality of the RCTs. Continuous outcome measures were pooled using standardized mean differences. Dichotomous outcome measures were pooled using Peto Odds Ratios.

MAIN RESULTS

Collectively, the 16 identified RCTs provided evidence that glucosamine is both effective and safe in OA. In the 13 RCTs in which glucosamine was compared to placebo, glucosamine was found to be superior in all RCTs, except one. In the four RCTs in which glucosamine was compared to an NSAID, glucosamine was superior in two, and equivalent in two.

REVIEWER'S CONCLUSIONS

Further research is necessary to confirm the long term effectiveness and toxicity of glucosamine therapy in OA. Most of the trials reviewed only evaluated the Rotta preparation of glucosamine sulfate. It is not known whether different glucosamine preparations prepared by different manufacturers are equally effective in the therapy of OA.

Sulfated glycosaminoglycans and glucosamine may synergize in promoting synovial hyaluronic acid synthesis

High-molecular-weight hyaluronic acid (HA) produced by the synovium may function physiologically to aid preservation of cartilage structure and prevent arthritic pain; both the size and concentration of HA in synovial fluid are diminished in osteoarthritis (OA). Glucosamine therapy for OA can be expected to increase synovial HA production by providing rate-limiting substrate. In addition, certain sulfated glycosaminoglycans and polysaccharides - including chondroitin sulfate (CS), dermatan sulfate, and pentosan polysulfate - stimulate synovial HA production, apparently owing to a hormone-like effect triggered by the binding of these polymers to membrane proteins of synovial cells. Surprisingly, a significant proportion of orally administered CS is absorbed as intact polymers - apparently by pinocytosis. These considerations may rationalize clinical studies concluding that oral CS provides slow-onset but durable pain relief and functional improvement in OA. The possibility that oral glucosamine and CS may interact in a complementary or synergistic fashion to improve synovial fluid HA content in OA should be assessed in clinical studies, and the potential of adjunctive CS administration to improve the clinical response achievable with optimal intakes of glucosamine should likewise be evaluated. In light of the fact that the synovium virtually functions as a 'placenta' for cartilage, focusing on synovium as the target for therapeutic intervention in OA may be a rational strategy.

Glucosamine sulfate modulates dysregulated activities of human osteoarthritic chondrocytes in vitro

OBJECTIVE

The efficacy of glucosamine sulfate (GS) in the symptomatic treatment of patients with osteoarthritis (OA) is suggested to be mediated by still unknown effects on the altered OA cartilage.

DESIGN

Using human OA chondrocytes in culture, the effects of GS on protein synthesis, caseinase, collagenase, phospholipase A2 (PLA2) and protein kinase C (PKC) activities as well as production of nitric oxide and cyclic AMP were studied in both cells and culture medium.

RESULTS

GS significantly reduced PLA2 activity, and more modestly collagenase activity, in the OA chondrocytes in a dose-dependent manner. By contrast, PLA2 and collagenase activity of the culture medium was not modified. No effects on caseinase activity was seen. GS significantly and dose-dependently increased protein synthesis. GS did not modify nitric oxide and cAMP production but significantly increased PKC production.

CONCLUSION

GS modified cultured OA chondrocyte metabolism by acting on PKC, cellular PLA2, protein synthesis and possibly collagenase activation. Extrapolation of the effect to the in-vivo situation remains hypothetical but they might represent some possible mechanisms of action of the drug in human.

Application to a cartilage targeting strategy: synthesis and in vivo biodistribution of (14)C-labeled quaternary ammonium-glucosamine conjugates

As part of a cartilage targeting program based on the affinity of the quaternary ammonium (QA) moiety for cartilage, QA derivatives of D-glucosamine (DG), an antirheumatic drug exhibiting a natural tropism for cartilaginous tissues, were designed and evaluated by pharmacokinetic studies. Two QA-DG conjugates were synthesized and labeled with (14)C by cross-linking the QA entity (trimethylammonium or pyridinium) to [(14)C]DG via an amide bond in a two-step procedure. After intravenous injection to male Sprague-Dawley rats, the two (14)C-labeled conjugates exhibited similar pharmacokinetic profiles, but their behavior clearly differed from that of unconjugated DG in several ways. (i) The tissue distribution for the conjugates was more restricted, with a decreased radioactivity level for whole tissues except for kidney, cartilage, and skin. (ii) The radioactivity concentrated more rapidly and strongly in cartilage for the conjugates than for DG for the short times after injection; on the other hand, 1 h after administration, the radioactivity level in cartilage was higher for DG, this result being consistent with the tropism already observed for this compound. (iii) Both conjugates were eliminated predominantly by the urinary route (85%); the radioactivity level in urine for DG was lower (45% of the injected dose), and significant (14)CO(2) was found in expired air, indicating metabolization and utilization of DG for energy-consuming processes. (iv) Blood and plasma kinetics studies displayed an enterohepatic cycle for DG, whereas for the QA conjugates, a rapid disappearance was observed. (v) HPLC analyses of plasma and urine indicated a low degree of metabolization for the conjugates, most of the radioactivity recovered in urine and plasma corresponding to the unchanged molecule. This study demonstrates that the introduction of the QA moiety on DG modifies its biodistribution and lends it a greater specificity for cartilage, at least for short times after injection. These findings justify further work on QA derivatives of other antirheumatic agents.

Glucosamine and chondroitin sulfates in the treatment of osteoarthritis: a survey

For more than 30 years, non-steroidal anti-inflammatory drugs (NSAIDs) have been used as standards in the treatment of osteoarthritis (OA). Serious and often life-threatening adverse effects due to these agents are common. Clinical findings have revealed that glucosamine sulfate and chondroitin sulfate are effective and safer alternatives to alleviate symptoms of OA. Experimental evidence indicates that these compounds and their low molecular weight derivatives have a particular tropism for cartilage where they serve as substrates in the biosynthesis of component building blocks. This paper is a literature review of the chemistry, mechanism of action, pharmacokinetics, clinical efficacy and safety of these two nutraceuticals.

Niacinamide therapy for osteoarthritis--does it inhibit nitric oxide synthase induction by interleukin 1 in chondrocytes?

Fifty years ago, Kaufman reported that high-dose niacinamide was beneficial in osteoarthritis (OA) and rheumatoid arthritis. A recent double-blind study confirms the efficacy of niacinamide in OA. It may be feasible to interpret this finding in the context of evidence that synovium-generated interleukin-1 (IL-1), by inducing nitric oxide (NO) synthase and thereby inhibiting chondrocyte synthesis of aggrecan and type II collagen, is crucial to the pathogenesis of OA. Niacinamide and other inhibitors of ADP-ribosylation have been shown to suppress cytokine-mediated induction of NO synthase in a number of types of cells; it is therefore reasonable to speculate that niacinamide will have a comparable effect in IL-1-exposed chondrocytes, blunting the anti-anabolic impact of IL-1. The chondroprotective antibiotic doxycycline may have a similar mechanism of action. Other nutrients reported to be useful in OA may likewise intervene in the activity or synthesis of IL-1. Supplemental glucosamine can be expected to stimulate synovial synthesis of hyaluronic acid; hyaluronic acid suppresses the anti-catabolic effect of IL-1 in chondrocyte cell cultures, and has documented therapeutic efficacy when injected intra-articularly. S-adenosylmethionine (SAM), another proven therapy for OA, upregulates the proteoglycan synthesis of chondrocytes, perhaps because it functions physiologically as a signal of sulfur availability. IL-1 is likely to decrease SAM levels in chondrocytes; supplemental SAM may compensate for this deficit. Adequate selenium nutrition may down-regulate cytokine signaling, and ample intakes of fish oil can be expected to decrease synovial IL-1 production; these nutrients should receive further evaluation in OA. These considerations suggest that non-toxic nutritional regimens, by intervening at multiple points in the signal transduction pathways that promote the synthesis and mediate the activity of IL-1, may provide a substantially superior alternative to NSAIDs (merely palliative and often dangerously toxic) in the treatment and perhaps prevention of OA.

Glycoaminoglycan (GAG) deficiency in protective barrier as an underlying, primary cause of ulcerative colitis, Crohn's disease interstitial cystitis and possibly Reiter's syndrome

Ulcerative colitis, Crohn's disease and interstitial cystitis share many common features, the most important of which is a defect in the glycoaminoglycan (GAG) defensive barrier. This defect allows penetration of toxins causing localized inflammatory response, followed by fibrosis and distant pathological changes, together with a myriad of biochemical and immunological changes. The latter has caused confusion as to etiology of the aforementioned disorders. This hypothesis is somewhat supported by the fact that agents such as glucosamine and pentosan polysulphate (Elmiron) that replace the GAG layer, improve the conditions. The potential for extrapolation of this hypothesis to atherosclerosis and arthropathies exists. There is a great danger in modern medical research that if one misses the wood for the trees, one becomes hopelessly lost in the minutiae of research. At present, it is embarrassing that ulcerative colitis (UC), Crohn's (CR) and interstitial cystitis (IC) are the cause of a great deal of morbidity and occasionally mortality, yet after intensive research, the etiology and effective treatment eludes us. The research in the past has focused extensively on inflammatory response in the mucosal lining, and biochemical, infective and immunological changes in the serum. This has led to a vast array of research pathways that seem at the present time to be totally lost and, might I say, aimless in direction, as a cause for these conditions, that remain amongst the most imperically treated in modern medicine. Another possible syndrome in this class would be Reiter's, which has many features in common with the above. The basic tenet of a GAG deficiency hypothesis is that, as shown in Figure 1A, an intact GAG layer provides, firstly, a mechanical and electrostatic defence against penetration of infective agents, toxins, antigenic protein moieties, etc. and, secondly, the prevention of extravasation of body fluid components. A degraded GAG layer is the start of the disease cascade of the above group of illnesses.

Enhanced synovial production of hyaluronic acid may explain rapid clinical response to high-dose glucosamine in osteoarthritis

Anecdotal reports of rapid symptomatic response to high-dose glucosamine in osteoarthritis are not credibly explained by the traditional view that glucosamine promotes synthesis of cartilage proteoglycans. An alternative or additional possibility is that glucosamine stimulates synovial production of hyaluronic acid (HA), which is primarily responsible for the lubricating and shock-absorbing properties of synovial fluid. Many clinical and veterinary studies have shown that intra-articular injections of high-molecular-weight HA produce rapid pain relief and improved mobility in osteoarthritis. HA has anti-inflammatory and analgesic properties, and promotes anabolic behavior in chondrocytes. The concentration and molecular weight of synovial fluid HA are decreased in osteoarthritis; by reversing this abnormality, high-dose glucosamine may provide rapid symptomatic benefit, and in the longer term aid the repair of damaged cartilage.

Glucosamine

OBJECTIVE

To review the pharmacology and pharmacokinetics of glucosamine and critically evaluate currently available literature regarding its safety and efficacy.

DATA SOURCE

A MEDLINE search was conducted between January 1965 and May 1997. Key words used in the search were osteoarthritis, osteoarthrosis, gonarthrosis, and glucosamine. In addition, references cited in articles obtained from the MEDLINE search were reviewed for additional literature.

STUDY SELECTION AND DATA EXTRACTION

All articles were considered for inclusion in the review. Articles were excluded from critical evaluation for lack of randomization, lack of a control group, 30 or fewer study participants, inconsistent treatment regimen, incomplete dosing information, or incomplete reporting of results.

DATA SYNTHESIS

Osteoarthritis affects approximately 12% of the US population; the incidence increases with increasing age. Currently used pharmacologic treatments, including acetaminophen and nonsteroidal antiinflammatory drugs, do not slow or reverse the degenerative process in osteoarthritis. Glucosamine has recently received a great deal of attention from the public as a potential treatment of osteoarthritis, prompting healthcare professionals to investigate its clinical usefulness and potential for adverse effects. The drug has been proposed to stop and possibly reverse the degenerative process in osteoarthritis. Following absorption of an oral dose, glucosamine is incorporated into plasma proteins during first-pass metabolism, resulting in 26% bioavailability. Unbound glucosamine is concentrated in the articular cartilage. Each of the three critically evaluated studies reported a decrease in the symptoms of osteoarthritis (e.g., decreased Lequesne index, decreased pain severity, increased range of motion) for the glucosamine group, which was greater than that obtained in the control group. Flaws in study design, however, prevent the use of these results in modifying current clinical practice. Reported short-term adverse effects include mild gastrointestinal problems, drowsiness, skin reactions, and headache.

CONCLUSIONS

Improvement in the symptoms of osteoarthritis associated with the use of glucosamine has been observed in clinical trials; however, those trials have flaws in design and data analysis. Further research needs to be conducted before glucosamine can be recommended as a treatment for osteoarthritis.

Glucosamine for psoriasis?

Amphiregulin and transforming growth factor-alpha, agonists for the epidermal growth factor receptor, are the major autocrine growth factors for cultured keratinocytes, and their substantial overexpression in psoriatic lesions suggests that they are crucial to the basal hyperplasia that characterizes psoriasis. Amphiregulin binds to heparin and related highly sulfated polysaccharides, and exogenous heparin blocks its growth factor activity, rationalizing previous reports that psoriasis responds to heparin therapy. Differentiating keratinocytes produce increased amounts of protein-bound as well as free-chain heparan sulfates, which may function physiologically as amphiregulin antagonists. By promoting keratinocyte synthesis of these heparan sulfates, glucosamine administration may inhibit amphiregulin function and thus provide therapeutic benefit in psoriasis. Concurrent ingestion of fish oil, by impeding the excessive activation of protein kinase C, may decrease keratinocyte production of amphiregulin and other autocrine growth factors, thus complementing the postulated benefits of glucosamine.

Glucosamine may retard atherogenesis by promoting endothelial production of heparan sulfate proteoglycans

Heparan sulfate proteoglycans produced by vascular endothelium may function physiologically to restrain the migration, multiplication, and phenotypic transition of vascular smooth-muscle cells, and to maintain an anticoagulant luminal surface by bonding and activating antithrombin III. Thus, ample production of heparan sulfate proteoglycans may act to prevent atherosclerosis and its thrombotic complications. The ability of exogenous heparin to stimulate synthesis of heparan sulfate proteoglycans by vascular endothelium may be largely responsible for the positive outcomes of most controlled evaluations of low-dose heparin as a long-term therapy for coronary disease. Glucosamine, a biosynthetic precursor of mucopolysaccharides, can substantially enhance mucopolysaccharide production when added to cultured fibroblasts or chondrocytes; the clinical utility of oral glucosamine in osteoarthritis may reflect increased synthesis of cartilage proteoglycans. It is reasonable to speculate that exogenous glucosamine will likewise enhance heparan sulfate proteoglycans production by vascular endothelial cells, and, when administered orally in regimens comparable to those effective in osteoarthritis, will thereby act to retard atherogenesis.

Glucosamine for wound healing

The rapid production of hyaluronic acid by fibroblasts in the early stages of wound healing may be of crucial importance as hyaluronic acid stimulates the migration and mitosis of mesenchymal and epithelial cells. Increased levels of hyaluronic acid, as observed during fetal wound healing or as achieved by the topical application of hyaluronic acid during wound dressing, are associated with brisker healing and reduced scarring. Glucosamine availability appears to be rate-limiting for hyaluronic acid synthesis. Thus the administration of adequate amounts of glucosamine by mouth during the first few days after surgery or trauma can be expected to enhance hyaluronic acid production in the wound, promoting swifter healing and possibly diminishing complications related to scarring.

The neglect of glucosamine as a treatment for osteoarthritis--a personal perspective

Osteoarthritis results from progressive catabolic loss of cartilage proteoglycans, owing to an imbalance between synthesis and degradation. Standard drug therapy is only of palliative benefit and may exacerbate loss of cartilage. Glucosamine is an intermediate in mucopolysaccharide synthesis, and its availability in cartilage tissue culture can be rate-limiting for proteoglycan production. A number of double-blind studies dating from the early 1980s demonstrate that oral glucosamine decreases pain and improves mobility in osteoarthritis, without side effects. Nevertheless, medical researchers and physicians in the US have totally ignored this rational and safe therapeutic strategy. By mechanisms that are still unclear, the natural methyl donor S-adenosylmethionine also promotes production of cartilage proteoglycans, and is therapeutically beneficial in osteoarthritis in well-tolerated oral doses. These and other safe nutritional measures supporting proteoglycan synthesis, may offer a practical means of preventing or postponing the onset of osteoarthritis in older people or athletes.

The effect of chronic paracetamol administration to rats on the glycosaminoglycan content of patellar cartilage

Male Wistar rats were treated with paracetamol (200 mg/kg twice a day) for 2, 3, 4 and 9 weeks. During the first four weeks of paracetamol administration the serum sulfate concentration was significantly decreased. However, during the fourth until the ninth week, the serum sulfate concentration was only diminished to a small and insignificant extent. The paracetamol administration did not lead to serious liver or renal toxicity, as determined by alanine aminotransferase and creatinine levels in the serum of the rats. The paracetamol-induced serum sulfate depletion, observed during the first four weeks of the experiment, led to a significantly lower glycosaminoglycan content of the patellar cartilage of the rats after three and four weeks paracetamol treatment. When after the fourth week the serum sulfate concentration rose to nearly normal levels also the glycosaminoglycan content in the rat patellar cartilage reached control levels. These data indicate that the serum sulfate depletion might be the causative factor for the observed reduction in glycosaminoglycan content of rat patellar cartilage.

Bovine sesamoid bones: a culture system for anatomically intact articular cartilage

Medial sesamoid bones from the metacarpophalangeal joints of calves were used for prolonged culture of anatomically intact articular cartilage on its natural bone support. The cartilage remained viable during culture, without signs of degeneration. After 1 wk of culture the cartilage showed an increased proteoglycan synthesis, and some minor changes in the composition of newly synthesized proteoglycans were observed. In the next 7 wk all studied parameters remained constant, except for the rate of proteoglycan synthesis, which declined between 4 and 8 wk to values just below those measured at the start of culture. Despite the fact that newly synthesized proteoglycans showed some altered biochemical properties, the composition of the total pool of proteoglycans did not change during 8 wk of culture. The significance of this phenomenon is discussed. This new in vitro model of intact articular cartilage offers a promising alternative to in vivo studies because in contrast to other in vitro models no surgical injury of the cartilage is introduced.

International experience with etodolac therapy for rheumatoid arthritis: an interim report of comparative efficacy

Etodolac, a nonsteroidal anti-inflammatory drug (NSAID) of the pyranocarboxylic acid family, has been tested in international clinical trials as a therapy for rheumatoid arthritis (RA). Preliminary results of 8- to 12-week double-blind trials indicate that etodolac therapy (200 mg twice a day) compared favorably with piroxicam therapy (20 mg once a day) and diclofenac therapy (50 mg three times a day) as measured by improvement in scores of five efficacy assessments: number of painful joints, number of swollen joints, physician's global assessment, patient's global assessment, and pain intensity. Etodolac also was as effective as naproxen (500 mg twice a day) as measured by improvement in scores in the five efficacy assessments. The observation that etodolac is as efficacious as three commonly used NSAIDs should interest clinicians who attempt to tailor NSAID therapy to the needs of individual RA patients, since etodolac has previously demonstrated an excellent safety profile. However, these trials must be completed to verify these preliminary results in a greater number of patients.

Inhibition of glycosaminoglycan synthesis in anatomically intact rat patellar cartilage by paracetamol-induced serum sulfate depletion

We have studied the effect of low sulfate concentrations on the glycosaminoglycan synthesis in rat patellar cartilage in vivo as well as in vitro. The oral administration of 200 mg/kg paracetamol to male Wistar rats resulted in a significant reduction of the serum sulfate concentration. Reduced serum sulfate availability resulted in a 34% decrease of glycosaminoglycan synthesis in patellar cartilage. This is due to sulfate depletion since paracetamol had no direct effects on glycosaminoglycan synthesis and a slight but significant inhibitory effect on the catabolism of radiolabeled glycosaminoglycans in vitro. The glycosaminoglycans synthesized at low sulfate concentrations in vivo were similar to the glycosaminoglycans synthesized at physiological sulfate concentrations. Studying the effect of sulfate availability in vitro on glycosaminoglycan synthesis in patellar cartilage we found that incubation of rat patellae in medium containing less than 0.5 mM inorganic sulfate led to a decreased sulfate incorporation. The use of potential sulfate decreasing drugs can lead to inhibition of glycosaminoglycan synthesis. This argues for a reconsideration of the use of these drugs in patients with already dysfunctioning cartilage metabolism as in rheumatoid arthritis and osteoarthrosis.

Drug action on articular cartilage surface. An in vitro study using mouse femoral heads labeled with cationized ferritin

The direct effects on the cartilage articular surface of three anti-inflammatory drugs (Diclofenac, Pirprofen and acetyl-salicylic acid) and of a polysulfated glycosaminoglycan (Arteparon), were studied using an in vitro system in which BALB-c mouse femoral heads were incubated with the drugs. After incubation and labeling of the negative charges of the articular surfaces with cationized ferritin, the femoral heads were examined by electron microscopy. In addition, the effect of the drugs on the aggressive action of collagenase on the articular surface was tested using the same in vitro system. Diclofenac, Pirprofen and the polysulfated glycosaminoglycan did not alter the structure or the charge properties of the surface. Acetyl salicylic acid produced a slight disruption of the articular surface. The drugs studied had no effect on the disruptive action of collagenase.

A 3-month, double-blind study of proglumetacin and naproxen in the treatment of rheumatoid arthritis

A double-blind clinical trial was carried out on 2 parallel groups each of 20 in-and out-patients with classical or definite rheumatoid arthritis, to compare the efficacy and tolerance of proglumetacin, a new non-steroidal anti-inflammatory drug, with naproxen. Each patient received daily either 300 mg proglumetacin or 500 mg naproxen in two divided doses, at meals, over a period of 3 months. The whilst both drugs were effective in the long-term treatment of chronic rheumatoid arthritis, proglumetacin appeared to be somewhat more effective than naproxen in reducing the duration of morning stiffness, the articular inflammation score index, erythrocyte sedimentation rate and the dosage of concomitant basic medication. Few side-effects were reported but 1 of the 2 patients in the naproxen group who developed allergic reactions had to be withdrawn during the first few days of treatment.

Double-blind clinical evaluation of oral glucosamine sulphate in the basic treatment of osteoarthrosis

The efficacy and tolerance of oral glucosamine sulphate were tested against placebo in a prospective double-blind trial in 20 out-patients with established osteoarthrosis. Two capsules of either glucosaminene sulphate (250 mg) or placebo were administered 3-times daily over a period of 6 to 8 weeks. Articular pain, joint tenderness and restricted movement were semi-quantitatively scored 1 to 4 every 3 days, and individually averaged over the treatment period (overall composite score). Possible side-reactions were similarly scored upon positive questioning of the patients. Haematology, erythrocyte sedimentation rate, urine analysis and X-rays were recorded before and after treatment. Significant alleviation of symptoms was associated with the use of the active drug at the prescribed dose. Similarly, patients given glucosamine sulphate experienced earlier alleviation of symptoms compared with those who had placebo. The use of glucosamine sulphate also resulted in a significantly larger proportion of patients who experienced lessening or disappearance of symptoms within the trial period. No adverse reactions were reported by the patients treated with glucosamine, and no variation in laboratory tests was recorded.

Preliminary bioavailability study on protacine: a new, non-steroidal anti-inflammatory agent

Time versus concentration curves of unchanged protacine were measured in the blood of 5 healthy volunteers by high pressure liquid chromatography after a single oral dose of 4 capsules (600 mg). These curves showed a maximum at 8 hours after administration, with an absorption half-life of 3.4 hours, and were interpreted according to the two-compartment open model with invasion. The elimination half-life was found to be 10 hours. This may allow a maintenance treatment, where necessary, with 1 capsule (150 mg) of protacine twice daily and strongly suggests that, apart from acute cases, protacine would be particularly well suited for long-term treatment.