Glucosamine for osteoarthritis: magic, hype, or confusion? It's probably safe-but there's no good evidence that it works

Nutrient-Mediated Perception and Signalling in Human Metabolism: A Perspective of Nutrigenomics

The interaction between selective nutrients and linked genes involving a specific organ reveals the genetic make-up of an individual in response to a particular nutrient. The interaction of genes with food opens opportunities for the addition of bioactive compounds for specific populations comprising identical genotypes. The slight difference in the genetic blueprints of humans is advantageous in determining the effect of nutrients and their metabolism in the body. The basic knowledge of emerging nutrigenomics and nutrigenetics can be applied to optimize health, prevention, and treatment of diseases. In addition, nutrient-mediated pathways detecting the cellular concentration of nutrients such as sugars, amino acids, lipids, and metabolites are integrated and coordinated at the organismal level via hormone signals. This review deals with the interaction of nutrients with various aspects of nutrigenetics and nutrigenomics along with pathways involved in nutrient sensing and regulation, which can provide a detailed understanding of this new leading edge in nutrition research and its potential application to dietetic practice.

Cell Source-Dependent In Vitro Chondrogenic Differentiation Potential of Mesenchymal Stem Cell Established from Bone Marrow and Synovial Fluid of Camelus dromedarius

Simple Summary

This is the first study to demonstrate the establishment and subsequent analysis of attributes, including the chondrogenic capacity of mesenchymal stem cells (MSCs) from bone marrow (BM) and synovial fluid (SF) from the same donor Camelus dromedarius. MSCs of SF origin were notably more efficient in their chondrogenic capacity and represent a potential source for camel regenerative medicine addressing chondrocyte-related problems.

Abstract

Mesenchymal stem cells (MSCs) are promising multipotent cells with applications for cartilage tissue regeneration in stem cell-based therapies. In cartilage regeneration, both bone marrow (BM-MSCs) and synovial fluid (SF-MSCs) are valuable sources. However, the cellular characteristics and chondrocyte differentiation potential were not reported in either of the camel stem cells. The in vitro chondrocyte differentiation competence of MSCs, from (BM and SF) sources of the same Camelus dromedaries (camel) donor, was determined. Both MSCs were evaluated on pluripotent markers and proliferation capacity. After passage three, both MSCs showed fibroblast-like morphology. The proliferation capacity was significantly increased in SF-MSCs compared to BM-MSCs. Furthermore, SF-MSCs showed an enhanced expression of transcription factors than BM-MSCs. SF-MSCs exhibited lower differentiation potential toward adipocytes than BM-MSCs. However, the osteoblast differentiation potential was similar in MSCs from both sources. Chondrogenic pellets obtained from SF-MSCs revealed higher levels of chondrocyte-specific markers than those from BM-MSCs. Additionally, glycosaminoglycan (GAG) content was elevated in SF-MSCs related to BM-MSCs. This is, to our knowledge, the first study to establish BM-MSCs and SF-MSCs from the same donor and to demonstrate in vitro differentiation potential into chondrocytes in camels.

Prevalence of Glucosamine and Omega-3 Fatty Acid Use and Characteristics of Users among Mid-Age Women: Analysis of a Nationally Representative Sample of 10,638 Women

BACKGROUND

There has been a dramatic increase in the use of dietary supplements over the last few decades and both omega-3 fatty acids and glucosamine are two of the best-selling dietary supplements in many countries. An understanding of omega-3 fatty acids and glucosamine consumption is of significance to health care providers and for future health promotion activities.

METHODS

This research involved analysis of data collected from a nationally-representative sample of Australian women as part of the Australian Longitudinal Study on Women's Health (ALSWH). Participants' use of omega-3 fatty acids (FA), glucosamine, their demographics, health status and health care utilisation were measured. Analysis included logistic regression modelling.

RESULTS

Of the 10,638 women in the study, 26.8% reported use of omega-3 FA and 15.9% glucosamine. Women with osteoarthritis (OR=2.529; 95% CI: 2.190, 2.921), other arthritis (OR= 1.618; 95% CI: 1.375, 1.905), and joint pain (OR= 2.699; 95% CI: 2.305, 3.160) were more likely to use glucosamine (all p<0.001). In contrast, those with diabetes (OR= 0.471; 95% CI: 0.343, 0.646) or depression (OR= 0.764; 95% CI: 0.657, 0.887) were less likely to use glucosamine (both p<0.001). Women with osteoarthritis (OR=1.481; 95% CI: 1.297, 1.691) and joint pain (OR= 1.456; 95% CI: 1.306, 1.622) were more likely to use omega-3 FA (all p<0.001).

CONCLUSIONS

Substantial prevalence rates for use of glucosamine and omega-3 FA amongst mid-aged women highlights the need for health practitioners and policymakers to be mindful of the possible significant role of such supplement use as part of patient health-seeking behaviours.

Dietary supplements as disease-modifying treatments in osteoarthritis: a critical appraisal

An array of natural substances purported to possess disease-modifying qualities for osteoarthritis are designated as "dietary supplements" and thus avoid rigorous FDA regulation. Substantial scientific evidence for the efficacy of these agents is elusive.

The effect of glucosamine sulfate on the proliferative potential and glycosaminoglycan synthesis of nucleus pulposus intervertebral disc cells

STUDY DESIGN

On the basis of the similarities in the structure of cartilage and intervertebral disc and on the property of glucosamine of being the building block for the construction of proteoglycan aggregates, we investigated the compound's role in the proliferation of nucleus pulposus cells under iso- and hyperosmotic conditions, the putative activation of signaling cascades, and the induction of glycosaminoglycan production.

OBJECTIVE

We examined the mode of action of glucosamine in nucleus pulposus cells.

SUMMARY OF BACKGROUND DATA

Glucosamine that naturally occurs in cartilage tissues has been widely used for treating osteoarthritis, but its role in nucleus pulposus cells is largely unknown.

METHODS

The effect of glucosamine sulfate on the viability and proliferation of nucleus pulposus cells was assessed by the microculture tetrazolium test (MTT) assay, direct cell counting, and tritiated thymidine incorporation. Changes in the expression and phosphorylation profile of selected proteins were estimated by Western analysis. Glycosaminoglycan production was measured using the Blyscan assay.

RESULTS

We showed that glucosamine sulfate up to 1 mM did not influence the viability, proliferation rate, or novel DNA synthesis of nucleus pulposus cells in the presence or absence of elevated osmolality but induced the transient phosphorylation of p38 mitogen-activated protein kinase. The highest concentration used (10 mM) negatively affected cellular proliferation and resulted in deactivation of extracellular signal-regulated kinases and c-Jun N-terminal kinases. Interestingly, these effects resulted from an additional hyperosmotic stress provoked by glucosamine alone. Finally, we found that a long-term incubation with glucosamine leads to an increase in the glycosaminoglycan content of nucleus pulposus cells.

CONCLUSION

Glucosamine sulfate was not found to reverse the high osmolality-mediated delay of proliferation in nucleus pulposus cells needed for the maintenance of the tissue's homeostasis. In addition, glycosaminoglycan synthesis stimulated by glucosamine provides a possible promising clinical role for treating disc degenerative disorders.

Who uses glucosamine and why? A study of 266,848 Australians aged 45 years and older

OBJECTIVES

There has been a dramatic increase in the use of complementary medicines over recent decades. Glucosamine is one of the most commonly used complementary medicines in Western societies. An understanding of glucosamine consumption is of significance for public health and future health promotion. This paper, drawing upon the largest dataset to date with regards to glucosamine use (n = 266,844), examines the use and users of glucosamine amongst a sample of older Australians.

DESIGN

Analysis of the self-reported data on use of glucosamine, demographics and health status as extracted from the dataset of the 45 and Up Study, which is the largest study of healthy ageing ever undertaken in the Southern Hemisphere involving over 265,000 participants aged 45 and over.

RESULTS

Analysis reveals that 58,630 (22.0%) participants reported using glucosamine in the 4 weeks prior to the survey. Use was higher for those who were female, non-smokers, residing in inner/outer regional areas, with higher income and private health insurance. Of all the health conditions examined only osteoarthritis was positively associated with use of glucosamine, while cancer, heart attack or angina and other heart disease were all negatively associated with glucosamine use.

CONCLUSIONS

This study suggests that a considerable proportion of the Australia population aged 45 and over consume glucosamine. There is a need for health care practitioners to enquire with their patients about their use of glucosamine and for further attention to be directed to providing good quality information for patients and providers with regards to glucosamine products.

Review article: Glucosamine

It has been claimed that glucosamine is able to alleviate pain, slow down losses of, and even restore articular cartilage in patients with damaged or osteoarthritic joints. It is classified as a food additive or nutraceutical; therefore manufacturers do not need to comply with the same regulations that apply for quality assurance within the pharmaceutical industry. Osteoarthritis can be managed by pharmacological and non-pharmacological methods. It is controversial whether glucosamine sulphate is the first structure-modifying drug commercially available. Little evidence suggests that glucosamine is superior to a placebo treatment in restoring articular cartilage.

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.

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.

Osteoarthritis: rational approach to treating the individual

Osteoarthritis (OA) is the most common form of joint disease and the leading cause of pain and physical disability in older people. Risk factors for incidence and progression of osteoarthritis vary considerably according to the type of joint. Disease assessment is difficult and the relationship between the radiographic severity of joint damage and the incidence and severity of pain is only modest. Psychosocial and socio-economic factors play an important role. This chapter will discuss four main guiding principles to the management of OA: (1) to avoid overtreating people with mild symptoms; (2) to attempt to avoid doing more harm than good ('primum non nocere'); (3) to base patient management on the severity of pain, disability and distress, and not on the severity of joint damage or radiographic change; and (4) to start with advice about simple measures that patients can take to help themselves, and only progress to interventions that require supervision or specialist knowledge if simple measures fail. Effect sizes derived from meta-analyses of large randomized trials in OA are only small to moderate for most therapeutic interventions, but they are still valuable for patients and clinically relevant for physicians. Joint replacement may be the only option with a large effect size, but is only appropriate for the relatively small number of people with OA who have advanced disease and severe symptoms. The key to successful management involves patient and health professionals working together to develop optimal treatment strategies for the individual.

Discovery of 3,3-dimethyl-5-hydroxypipecolic hydroxamate-based inhibitors of aggrecanase and MMP-13

A series of pipecolic hydroxamate inhibitors of MMP-13 and aggrecanase was discovered based on screening known inhibitors of TNF-alpha converting enzyme (TACE). Potency versus aggrecanase was optimized by modification of the benzyloxyarylsulfonamide group. Incorporation of geminal alkyl substitution at the 3-position of the piperidine ring improved metabolic stability, presumably by increasing steric hindrance around the metabolically labile hydroxamic acid. This modification also resulted in dramatic improvement of aggrecanase activity with a slight reduction in selectivity versus MMP-1. Synthesis, structure activity relationships, and strategies to reduce metabolic clearance are described.

Osteoarthritis - an untreatable disease?

Osteoarthritis is a painful and disabling disease that affects millions of patients. Its aetiology is largely unknown, but is most likely multi-factorial. Osteoarthritis poses a dilemma: it often begins attacking different joint tissues long before middle age, but cannot be diagnosed until it becomes symptomatic decades later, at which point structural alterations are already quite advanced. In this review, osteoarthritis is considered as a disease of the whole joint that may result from multiple pathophysiological mechanisms, one of which is the dysregulation of lipid homeostasis. No proven disease-modifying therapy exists for osteoarthritis and current treatment options for chronic osteoarthritic pain are insufficient, but new pharmacotherapeutic options are emerging.

Tratamiento farmacológico de la artrosis. Expectativas y realidades

In order to assess agent with modulating properties of the course of the arthrosic condition, the so-called SYSADOA (Symptomatic Slow Acting Drugs for Osteoarthritis) and "structure modifiers" have been defined. Glucosamine sulfate, chrondroitin sulfate and diacerein have been considered among these agents. Based on the published data and according to the evidence available, the SYSADOA have symptomatic effects and can modify the structure. However, although there is scientific evidence for the use of these drugs in arthrosis treatment, the limited intensity of their action over the placebo makes it necessary to evaluate the clinical relevance of their application before recommending their generalized use.

Effect of oral glucosamine on cartilage degradation in a rabbit model of osteoarthritis

OBJECTIVE

To determine whether oral glucosamine alleviates cartilage degradation in an animal model of osteoarthritis (OA).

METHODS

The effect of 8 weeks of daily oral glucosamine hydrochloride on degeneration of articular cartilage was evaluated in rabbits in which anterior cruciate ligament transection (ACLT) was performed to induce OA. Animals were treated with glucosamine (n = 16) or a placebo (n = 16) and necropsied at 11 weeks. Seven unoperated rabbits served as controls. The articular cartilage was evaluated macroscopically and histologically and analyzed for total type II collagen and glycosaminoglycan (GAG) content.

RESULTS

Histologic analysis revealed that loss of proteoglycan, based on Safranin O-fast green staining, was significantly reduced in the lateral tibial plateau cartilage of ACL-transected limbs in the glucosamine group compared with ACL-transected limbs in the placebo group, with a similar, but not significant, trend for the lateral femoral condylar cartilage. Likewise, macroscopic analysis of cartilage showed that the lateral tibial plateau alone had a significantly lower rate of disease in the glucosamine group, which was consistent with the results of the independent histologic assessment. However, no significant treatment effect was detected when composite histologic scores were analyzed. A significant reduction in GAG content was observed in the femoral condyles of placebo-treated ACL-transected joints, but not in the same region of glucosamine-treated ACL-transected joints, compared with their respective contralateral unoperated joints.

CONCLUSION

Oral administration of glucosamine had a detectable, site-specific, partial disease-modifying effect in this model of OA. From a clinical perspective, the administration of glucosamine did not prevent fibrillation and/or erosions of the articular cartilage in all of the treated animals, and no effects were detected in the medial joint compartments.

Effectiveness of glucosamine for symptoms of knee osteoarthritis: results from an internet-based randomized double-blind controlled trial

PURPOSE

To present the safety and effectiveness results of a prototypical 12-week, double-blind, randomized placebo-controlled trial of glucosamine among subjects with knee osteoarthritis who were recruited and followed entirely over the Internet.

METHODS

The study comprised 205 subjects aged 45 years or older with symptomatic knee osteoarthritis who were recruited over the Internet; eligibility was authenticated through medical record review. Participants were assigned randomly to 1.5 g/d of glucosamine (n = 101) or placebo (n = 104), of whom 108 completed the intervention (93 in each arm). The primary outcome measure was the pain subscale of the Western Ontario and McMaster Universities Osteoarthritis Index (Likert version). Additional outcome measures included the physical function and stiffness subscales and overall score of the questionnaire, and analgesic use.

RESULTS

There was no difference between treatment and control groups in terms of change in pain score (2.0 +/- 3.4 vs. 2.5 +/- 3.8, P = 0.41), stiffness (0.7 +/- 1.6 vs. 0.8 +/- 1.5, P = 0.52), physical function (5.2 +/- 9.5 vs. 4.6 +/- 9.6, P = 0.49), overall score (7.8 +/- 13.1 vs. 7.8 +/- 13.5, P = 0.81), and analgesic use (133 +/- 553 vs. -88 +/- 755, P = 0.12). Stratification by osteoarthritis severity, glucosamine product, and use of a nonsteroidal anti-inflammatory drug, as well as exclusion of opiate users, did not alter the results. The number and type of adverse events reported was similar between the groups.

CONCLUSION

Our results suggest that although glucosamine appears to be safe, it is no more effective than placebo in treating the symptoms of knee osteoarthritis.

What is important in treating osteoarthritis? Whom should we treat and how should we treat them?

Most of the treatments used today for OA have a relatively weak evidence base to support their use, and their effect size is small. Many key questions about OA management remain unanswered, in part because of the strong bias toward research on single pharmaceutical agents rather than nonpharmacologic interventions and a comprehensive package of care involving pharmacologic and nonpharmacologic measures. Good management of OA involves the coordination of several different types of interventions provided by health care professionals; however, while a great deal of research is available on the use of individual treatments, there is a lack of information on how health services for patients who have OA should be organized. The problem is compounded by the fact that many people who have OA use complementary therapy as well as, or instead of, allopathic treatments despite the fact that most of the evidence suggests that many such interventions are no better than placebo [123], which might be because of the relatively small effects of most conventional nonsurgical treatment for OA and to the need for a more holistic, individualized approach to treatment than most conventional health professionals usually provide. For many people who have OA, the fear of side effects is a major barrier to the use of pharmacologic interventions [11]. The authors believe that future research in OA therapeutics should concentrate more on behavioral and physical interventions than on drugs, should examine packages of care involving combinations of treatment modalities, and should include a consideration of patient preferences. The authors also believe that the academic community striving to provide help for people who have OA should bear in mind the concept that there is "too much medicine" [37].

'Natural remedies' in the treatment of osteoarthritis

Osteoarthritis (OA) is a common, chronic and painful condition. It is the most common of all rheumatic disorders and is destined to become one of the most prevalent and costly diseases in our society. The conventional therapeutic options employed in the management of OA are simple analgesics and NSAIDs, but these options frequently produce sub-optimal benefit and are associated with an adverse-safety profile. Unsurprisingly patients are looking to alternative and complementary medicine. The aim of this article was to review the available literature on the effectiveness and safety of 'natural remedies' for the treatment of OA. Computerised literature searches were carried out for systematic reviews and randomised controlled trials examining the role of 'natural remedies' in the treatment of OA. There have been few randomised controlled trials of 'natural remedies' that have satisfied the internationally agreed standards. There was, however, evidence of efficacy for glucosamine, chondroitin sulfate and possibly avocado/soybean unsaponifiables for the symptomatic relief of OA. To date, it is not established whether any of the 'natural remedies' are capable of chondroprotection. Even if 'natural remedies' are only modestly effective, they are widely available and well tolerated, suggesting that they may play a significant role in the management of OA in the elderly.

Glucosamine and chondroitin sulfate supplementation to treat symptomatic disc degeneration: biochemical rationale and case report

BACKGROUND

Glucosamine and chondroitin sulfate preparations are widely used as food supplements against osteoarthritis, but critics are skeptical about their efficacy, because of the lack of convincing clinical trials and a reasonable scientific rationale for the use of these nutraceuticals. Most trials were on osteoarthritis of the knee, while virtually no documentation exists on spinal disc degeneration. The purpose of this article is to highlight the potential of these food additives against cartilage degeneration in general, and against symptomatic spinal disc degeneration in particular, as is illustrated by a case report. The water content of the intervertebral disc is a reliable measure of its degeneration/ regeneration status, and can be objectively determined by Magnetic Resonance Imaging (MRI) signals.

CASE PRESENTATION

Oral intake of glucosamine and chondroitin sulfate for two years associated with disk recovery (brightening of MRI signal) in a case of symptomatic spinal disc degeneration. We provide a biochemical explanation for the possible efficacy of these nutraceuticals. They are bioavailable to cartilage chondrocytes, may stimulate the biosynthesis and inhibit the breakdown of their extracellular matrix proteoglycans.

CONCLUSION

The case suggests that long-term glucosamine and chondroitin sulfate intake may counteract symptomatic spinal disc degeneration, particularly at an early stage. However, definite proof requires well-conducted clinical trials with these food supplements, in which disc de-/regeneration can be objectively determined by MRI. A number of biochemical reasons (that mechanistically need to be further resolved) explain why these agents may have cartilage structure- and symptom-modifying effects, suggesting their therapeutic efficacy against osteoarthritis in general.

Glucosamine sulfate modulates the levels of aggrecan and matrix metalloproteinase-3 synthesized by cultured human osteoarthritis articular chondrocytes

OBJECTIVE

The functional integrity of articular cartilage is determined by a balance between chondrocyte biosynthesis of extracellular matrix and its degradation. In osteoarthritis (OA), the balance is disturbed by an increase in matrix degradative enzymes and a decrease in biosynthesis of constitutive extracellular matrix molecules, such as collagen type II and aggrecan. In this study, we examined the effects of the sulfate salt of glucosamine (GS) on the mRNA and protein levels of the proteoglycan aggrecan and on the activity of matrix metalloproteinase (MMP)-3 in cultured human OA articular chondrocytes.

DESIGN

Freshly isolated chondrocytes were obtained from knee cartilage of patients with OA. Levels of aggrecan and MMP-3 were determined in culture media by employing Western blots after incubation with GS at concentrations ranging from 0.2 to 200 microM. Zymography (casein) was performed to confirm that effects observed at the protein level were reflected at the level of enzymatic activity. Northern hybridizations were used to examine effects of GS on levels of aggrecan and MMP-3 mRNA. Glycosaminoglycan (GAG) assays were performed on the cell layers to determine levels of cell-associated GAG component of proteoglycans.

RESULTS

Treatment of OA chondrocytes with GS (1.0-150 microM) resulted in a dose-dependent increase in aggrecan core protein levels, which reached 120% at 150 microM GS. These effects appeared to be due to increased expression of the corresponding gene as indicated by an increase in aggrecan mRNA levels in response to GS. MMP-3 levels decreased (18-65%) as determined by Western blots. Reduction of MMP-3 protein was accompanied by a parallel reduction in enzymatic activity. GS caused a dose-dependent increase (25-140%) in cell-associated GAG content. Chondrocytes obtained from 40% of OA patients failed to respond to GS.

CONCLUSIONS

The results indicate that GS can stimulate mRNA and protein levels of aggrecan core protein and, at the same time, inhibit production and enzymatic activity of matrix-degrading MMP-3 in chondrocytes from OA articular cartilage. These results provide a cogent molecular mechanism to support clinical observations suggesting that GS may have a beneficial effect in the prevention of articular cartilage loss in some patients with OA.

Glucosamine

Glucosamine occurs naturally in all human tissues. It stimulates the synthesis of glycosaminoglycan, proteoglycan and hyaluronic acid, although the precise mechanism of action remains to be established. Formulated as glucosamine sulphate (Dona) and various others), glucosamine has been evaluated for its efficacy in relieving the symptoms of osteoarthritis and its disease-modifying potential. In two large randomised, double-blind, multicentre studies in patients with osteoarthritis, oral or intramuscular glucosamine for 4-6 weeks was associated with a greater decrease in symptom severity (as assessed by the Lequesne index) than placebo. In addition, there was a greater proportion of responders (defined as patients with a >or=3-point reduction in the Lequesne index, along with a positive overall assessment by the investigator) at the end of the treatment period with glucosamine than with placebo. In two large 4-week trials, oral glucosamine produced similar improvements to ibuprofen in the Lequesne index in one study and in articular pain scores in the other study. In a smaller 8-week comparative trial, oral glucosamine therapy achieved a significantly greater improvement in articular pain score than ibuprofen, and the investigators rated treatment efficacy as 'good' in a significantly greater proportion of glucosamine than ibuprofen recipients. In comparison with piroxicam, glucosamine significantly improved arthritic symptoms after 12 weeks of therapy and remained effective 8 weeks after treatment was discontinued. Beneficial effects of long-term oral glucosamine therapy in preventing joint space narrowing and improving symptoms were shown in two 3-year placebo-controlled trials in a total of 414 patients with osteoarthritis. Statistically significant differences favouring glucosamine were noted in the per-protocol and intention-to-treat analyses for the primary endpoints for both joint structural changes and symptom modification. Glucosamine has a tolerability profile similar to that of placebo and is better tolerated than ibuprofen or piroxicam. In particular, glucosamine recipients had a markedly lower incidence of gastrointestinal disturbances than those receiving ibuprofen. Other adverse events reported in both glucosamine and ibuprofen recipients were pruritus or skin reactions, flushing and fatigue. In general, a lower incidence of withdrawal from clinical trials was reported for glucosamine recipients than either ibuprofen or piroxicam recipients.

CONCLUSION

In short-term clinical trials, glucosamine provided effective symptomatic relief for patients with osteoarthritis of the knee. In addition, glucosamine has shown promising results in modifying the progression of arthritis over a 3-year period. Glucosamine may therefore prove to be a useful treatment option for osteoarthritis.

Oral and intra-articular remedies: Review of papers published from March 2001 to February 2002

There have been considerable advances in the drug treatments used to treat osteoarthritis. The development of selective cyclo-oxygenase inhibitors (COX-II) and confirmation of their efficacy and gastrointestinal safety will reduce treatment morbidity in the elderly. Guidelines for safe and appropriate use of COX-II drugs are now available. The role of anti-inflammatory drugs in precipitating cardiorenal events has been highlighted but remains to be fully evaluated. Glucosamine, diacerein, and hyaluronan may all be disease-modifying drugs for osteoarthritis but confirmatory studies are still needed.