Comparison of pharmacokinetics of glucosamine and synovial fluid levels following administration of glucosamine sulphate or glucosamine hydrochloride

The short-term effect of glucosamine-sulfate, nonanimal chondroitin-sulfate, and S-adenosylmethionine combination on ultrasonography findings, inflammation, pain, and functionality in patients with knee osteoarthritis: A pilot, double-blind, randomized, placebo-controlled clinical trial

Objectives

This study aimed to investigate the efficacy of glucosamine-sulfate (GS), nonanimal chondroitin-sulfate (naCS), and S-adenosylmethionine (SAMe) combination on ultrasound findings, inflammation, pain, and functionality in knee osteoarthritis.

Patients and methods

In the prospective, randomized, double-blind, placebo-controlled pilot study conducted between August 2019 and November 2019, 120 participants (28 males, 92 females; mean age: 66.4±7.9 years; range, 42.4 to 74.5 years) were randomized at a 1:1:1 ratio to the placebo group, the first experimental group (a combination of GS, naCS, and SAMe was administered to the experimental groups. The first experimental group received 375 mg of GS, 300 mg of naCS, and 100 mg of SAMe, whereas the second experimental group received 750 mg of GS, 600 mg of naCS, and 200 mg of SAMe). Laboratory (erythrocyte sedimentation rate, C-reactive protein, tumor necrosis factor alpha, interleukin [IL]-1β, IL-6, IL-17), clinical (Visual Analog Scale [VAS], short form health survey [SF-36], the Western Ontario and McMaster Universities Arthritis Index [WOMAC], and the Tegner Lysholm Knee Scoring Scale [TLKS]), and musculoskeletal ultrasound (MSUS) assessments were performed at baseline and after three and six months.

Results

A minor increase was observed in the second experimental group after six months using ultrasonography to evaluate articular cartilage thickness (p<0.05). The investigational product's superiority in reducing osteoarthritis ultrasonographic findings was not proven. A moderately negative association was found between cartilage thickness and VAS scores at baseline (ρ=-0.36, p<0.01), while the presence of massive osteophytes on MSUS showed a low to moderate association with all clinical outcomes. There was no difference in the delta changes between groups for the VAS, TLKS, WOMAC, and SF-36. The only serum inflammatory marker outside the reference range was IL-1β, but no significant changes were observed after six months.

Conclusion

According to the results of our investigation, treatment for knee osteoarthritis should be evaluated using more objective outcomes. The most important conclusion of our study is that IP may result in a slight increase in articular cartilage thickness, which was associated with a decrease in pain intensity at baseline. Clarification of the potential influence of this combination on radiographic progression and laboratory markers of inflammation requires further exploration.

Conjugated linoleic acid and glucosamine supplements may prevent bone loss in aging by regulating the RANKL/RANK/OPG pathway

The skeleton is a living organ that undergoes constant changes, including bone formation and resorption. It is affected by various diseases, such as osteoporosis, osteopenia, and osteomalacia. Nowadays, several methods are applied to protect bone health, including the use of hormonal and non-hormonal medications and supplements. However, certain drugs like glucocorticoids, thiazolidinediones, heparin, anticonvulsants, chemotherapy, and proton pump inhibitors can endanger bone health and cause bone loss. New studies are exploring the use of supplements, such as conjugated linoleic acid (CLA) and glucosamine, with fewer side effects during treatment. Various mechanisms have been proposed for the effects of CLA and glucosamine on bone structure, both direct and indirect. One mechanism that deserves special attention is the regulatory effect of RANKL/RANK/OPG on bone turnover. The RANKL/RANK/OPG pathway is considered a motive for osteoclast maturation and bone resorption. The cytokine system, consisting of the receptor activator of the nuclear factor (NF)-kB ligand (RANKL), its receptor RANK, and its decoy receptor, osteoprotegerin (OPG), plays a vital role in bone turnover. Over the past few years, researchers have observed the impact of CLA and glucosamine on the RANKL/RANK/OPG mechanism of bone turnover. However, no comprehensive study has been published on these supplements and their mechanism. To address this gap in knowledge, we have critically reviewed their potential effects. This review aims to assist in developing efficient treatment strategies and focusing future studies on these supplements.

Pharmacokinetic Assessment of Staphylococcal Phage K Following Parenteral and Intra-articular Administration in Rabbits

The therapeutic value of phage as an alternative to antibiotics for the treatment of bacterial infections is being considered in the wake of mounting antibiotic resistance. In this study, the pharmacokinetic properties of Staphylococcus aureus phage K following intravenous and intra-articular administration were investigated in a rabbit model. Using a traditional plaque assay and a novel quantitative PCR assay to measure phage levels in specimens over time, it was found that intra-articularly administered phage enters the systemic circulation; that phage may be detected in synovial fluid up to 24 h following the intra-articular, but not intravenous, administration; and that qPCR-based enumeration is generally more sensitive than plaque enumeration, with fair to moderate correlation between the two methods. Findings presented should inform the design of phage therapy experiments and therapeutic drug monitoring in preclinical and human phage studies.

Proposed Canadian Consensus Guidelines on Osteoarthritis Treatment Based on OA-COAST Stages 1–4

The Canadian consensus guidelines on OA treatment were created from a diverse group of experts, with a strong clinical and/or academic background in treating OA in dogs. The document is a summary of the treatment recommendations made by the group, with treatments being divided into either a core or secondary recommendation. Each treatment or modality is then summarized in the context of available research based support and clinical experience, as the treatment of OA continues to be a multimodal and commonly a multidisciplinary as well as individualized approach. The guidelines aim to help clinicians by providing clear and clinically relevant information about treatment options based on COAST defined OA stages 1–4.

[Symptomatic slow-acting drugs in the treatment of osteoarthritis: focus on glucosamine preparations]

The article discusses the place of symptomatic slow-acting drugs in current guidelines for the treatment of osteoarthritis. Special emphasis is put ot glucosamine preparations, the attitude towards which, until recently, was ambiguous. The results of experimental and clinical studies demonstrating the advantages of crystalline glucosamine sulfate over preparations/food additives of glucosamine hydrochloride are presented. The differences in the pharmacodynamics and pharmacokinetics of glucosamine sulfate and glucosamine hydrochloride, which may be the reason for the ineffectiveness of the latter in clinical trials, are discussed.

[Alflutop - in modern symptom - modifying osteoarthritis therapy]

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

Glucosamine and chondroitin use in canines for osteoarthritis: A review

Osteoarthritis is a slowly progressive and debilitating disease that affects canines of all breeds. Pain and decreased mobility resulting from osteoarthritis often have a negative impact on the affected canine’s quality of life, level of comfort, daily functioning, activity, behaviour, and client-pet companionship. Despite limited and conflicting evidence, the natural products glucosamine hydrochloride (HCl) and chondroitin sulfate are commonly recommended by veterinarians for treating osteoarthritis in dogs. There is a paucity of well-designed clinical veterinary studies investigating the true treatment effect of glucosamine and chondroitin. The purposes of this review article are to provide a brief background on glucosamine and chondroitin use in canine osteoarthritis and to critically review the available literature on the role of these products for improving clinical outcomes. Based on critical review, recommendations for practice are suggested and a future study design is proposed.

Glucosamine and chondroitin for the treatment of osteoarthritis

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

The preventive effects of two nutraceuticals on experimentally induced acute synovitis

BACKGROUND

Nutraceuticals are often used in the management of equine osteoarthritis, but scientific evidence of their efficacy is lacking.

OBJECTIVES

To study the preventive effects of two new nutraceuticals after the experimental induction of synovitis in comparison with positive and negative control treatments.

STUDY DESIGN

Blinded, controlled, randomised experiment.

METHODS

Twenty-four healthy Standardbred horses were randomly allocated to supplement AT (multi-ingredient, 28 days), supplement HP (collagen hydrolysate, 60 days), meloxicam (4 days) or placebo (60 days). Synovitis was induced in the right intercarpal joint by intra-articular injection of 0.5 ng lipopolysaccharide (LPS) of Escherichia coli while treatments were continued. Blood and synovial fluid were sampled before treatment, immediately prior to LPS injection, and at 8, 24 and 48 h post-injection. Synovial fluid samples were analysed for total nucleated cell count (TNCC), total protein (TP) and selected biomarkers (prostaglandin E₂ [PGE₂ ], interleukin-6 [IL-6], glycosaminoglycans [GAGs], type II collagen synthesis [CPII], matrix metalloproteinase [MMP]). Lameness was scored by visual examination and pressure plate analysis immediately prior to LPS injection, and at 8, 24 and 48 h post-injection. Clinical examinations were performed before treatment, immediately prior to LPS injection, at 2, 4 and 6 h post-injection, and then twice per day during the test period.

RESULTS

Before treatment and intra-articular challenge, there were no statistically significant differences among the treatment groups for any of the parameters. After intra-articular challenge, the placebo group showed significantly higher synovial fluid TP, TNCC and PGE₂ compared with the meloxicam group, although the model did not induce a relevant amount of lameness. Both nutraceuticals resulted in significantly lower synovial fluid TP, TNCC and PGE₂ compared with placebo. No statistical differences in IL-6, GAGs, CPII or MMPs were observed among treatment groups. No adverse effects were observed.

MAIN LIMITATIONS

Despite evidence of synovitis, lameness was too mild to detect.

CONCLUSIONS

The preventive administration of these nutraceuticals showed anti-inflammatory effects in this validated synovitis model. Therefore, further studies of their clinical applicability are warranted.

A highly selective turn-on fluorescent sensor for glucosamine from amidoquinoline-napthalimide dyads

Three amidoquinoline-naphthalimide dyads are designed and synthesized in 67-73% overall yields in 3 steps from commercially available starting materials. Compounds with unsubstituted and nitro naphthalimide (1 and 2) show excellent selective fluorescent responses towards glucosamine with the enhancement of fluorescence quantum yields by 14 folds. The determination of HOMO-LUMO levels by linear sweep voltammetry suggests that the sensing mechanism likely involves the inhibition of photo-induced electron transfer (PET) between the aminoquinoline and naphthalimide moieties by glucosamine. The association constants of 1.55×10(4) and 1.45×10(4)M(-)(1), along with the glucosamine detection limits of 1.06 and 0.29µM are determined for 1 and 2, respectively. The application of 2 as a fluorescent probe for real-time detection of cellular glucosamine at micromolar level in living Caco-2 cells is also demonstrated.

The effects of glucosamine sulfate on intervertebral disc annulus fibrosus cells in vitro

BACKGROUND CONTEXT

Glucosamine has gained widespread use among patients, despite inconclusive efficacy data. Inconsistency in the clinical literature may be related to lack of understanding of the effects of glucosamine on the intervertebral disc, and therefore, improper patient selection.

PURPOSE

The goal of our study was to investigate the effects of glucosamine on intervertebral disc cells in vitro under the physiological conditions of inflammation and mechanical loading.

STUDY DESIGN

Controlled in vitro laboratory setting.

METHODS

Intervertebral disc cells isolated from the rabbit annulus fibrosus were exposed to glucosamine sulfate in the presence and absence of interleukin-1β and tensile strain. Outcome measures included gene expression, measurement of total glycosaminoglycans, new proteoglycan synthesis, prostaglandin E2 production, and matrix metalloproteinase activity. The study was funded by NIH/NCCAM, and the authors have no conflicts of interest.

RESULTS

Under conditions of inflammatory stimulation alone, glucosamine demonstrated a dose-dependent effect in decreasing inflammatory and catabolic mediators and increasing anabolic genes. However, under conditions of mechanical stimulation, although inflammatory gene expression was decreased, PGE2 was not. In addition, matrix metalloproteinase-3 gene expression was increased and aggrecan expression decreased, both of which would have a detrimental effect on matrix homeostasis. Consistent with this, measurement of total glycosaminoglycans and new proteoglycan synthesis demonstrated detrimental effects of glucosamine under all conditions tested.

CONCLUSIONS

These results may in part help to explain the conflicting reports of efficacy, as there is biological plausibility for a therapeutic effect under conditions of predominate inflammation but not under conditions where mechanical loading is present or in which matrix synthesis is needed.

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

STUDY DESIGN

Laboratory based controlled in vivo study.

OBJECTIVE

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

SUMMARY OF BACKGROUND DATA

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

METHODS

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

RESULTS

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

CONCLUSION

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

Nutritional interventions to prevent and treat osteoarthritis. Part II: focus on micronutrients and supportive nutraceuticals

Osteoarthritis (OA) is the most common cause of musculoskeletal disability in the elderly, and it places an enormous economic burden on society, which will remain a major health care challenge with an aging population. Management of OA is primarily focused on palliative relief using agents such as nonsteroidal anti-inflammatory drugs (NSAID) and analgesics. However, such an approach is limited by a narrow therapeutic focus that fails to address the progressive and multimodal nature of OA. Given the favorable safety profile of most nutritional interventions, identifying disease-modifying pharmaconutrients capable of improving symptoms and also preventing, slowing, or even reversing the degenerative process in OA should remain an important paradigm in translational and clinical research. The goals of pharmaconutrition for metabolic optimization are to drive biochemical reactions in a desired direction and to meet health condition-specific metabolic demands. Applying advances in nutritional science to musculoskeletal medicine remains challenging, given the fluid and dynamic nature of the field, along with a rapidly developing regulatory climate over manufacturing and commerce requirements. The purpose of this article is to review the available literature on effectiveness and potential mechanism for OA of micronutrient vitamins; minerals; glycosaminoglycans; avocado-soybean unsaponifiable fractions; methylsulfonylmethane; s-adenosylmethionine; undenatured and hydrolyzed collagen preparations; phytoflavonoid compounds found in fruits, vegetables, spices, teas, and nuts; and other nutrients on the horizon. There also is a discussion on the concept of rational polysupplementation via the strategic integration of multiple nutraceuticals with potential complementary mechanisms for improving outcomes in OA. As applied nutritional science evolves, it will be important to stay on the forefront of proteomics, metabolomics, epigenetics, and nutrigenomics, because they hold enormous potential for developing novel therapeutic and prognostic breakthroughs in many areas of medicine, including OA.

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

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

Metabolomic analyses of blood plasma after oral administration of D-glucosamine hydrochloride to dogs

D-Glucosamine hydrochloride (GlcN∙HCl) is an endogenous amino monosaccharide synthesized from glucose that is useful in the treatment of joint diseases in both humans and animals. The aim of this study was to examine amino acid metabolism in dogs after oral administration of GlcN∙HCl. Accelerated fumarate respiration and elevated plasma levels of lactic acid and alanine were observed after administration. These results suggest that oral administration of GlcN∙HCl induces anaerobic respiration and starvation in cells, and we hypothesize that these conditions promote cartilage regeneration. Further studies are required to evaluate the expression of transforming growth factor-beta (TGF-β).

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

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

Precolumn derivatization LC-MS/MS method for the determination and pharmacokinetic study of glucosamine in human plasma and urine

A selective precolumn derivatization liquid chromatography-tandem mass spectrometric (LC-MS/MS) method for the determination of glucosamine in human plasma and urine has been developed and validated. Glucosamine was derivatized by o-phthalaldehyde/3-mercaptopropionic acid. Chromatographic separation was performed on a Phenomenex ODS column (150 mm×4.6 mm, 5 μm) using linear gradient elution by a mobile phase consisting of methanol (A), and an aqueous solution containing 0.2% ammonium acetate and 0.1% formic acid (B) at a flow rate of 1 mL/min. Tolterodine tartrate was used as the internal standard (IS). With protein precipitation by acetonitrile and then the simple one-step derivatization, a sensitive bio-assay was achieved with the lower limit of quantitation (LLOQ) as low as 12 ng/mL for plasma. The standard addition calibration curves suitable for clinical sample analysis showed good linearity over the range of 0.012-8.27 μg/mL in plasma and 1.80-84.1 μg/mL in urine. The fully validated method has been successfully applied to a pharmacokinetic study of compound glucosamine sulfate dispersible tablets in health Chinese volunteers receiving single oral doses at 500, 1000 and 1500 mg of glucosamine sulfate, as well as multiple oral doses of 500 mg t.i.d. for 7 consecutive days.

Experimental pharmacology of glucosamine sulfate

Several clinical studies demonstrated that glucosamine sulfate (GS) is effective in controlling osteoarthritis (OA), showing a structure-modifying action. However, little is known about the molecular mechanism(s) by which GS exerts such action and about the effects of GS at a tissue level on osteoarthritic cartilage and other joint structures. Here we provide mechanistic evidence suggesting that in vitro GS attenuates NF-κB activation at concentrations in the range of those observed after GS administration to volunteers and patients, thus strengthening previous findings. Furthermore, we describe the effects of GS at a tissue level on the progression of the disease in a relevant model of spontaneous OA, the STR/ort mouse. In this model, the administration of GS at human corresponding doses was associated with a significant decrease of OA scores. Histomorphometry showed that the lesion surface was also significantly decreased, while the number of viable chondrocytes within the matrix was significantly increased. GS improved the course of OA in the STR/Ort mouse, by delaying cartilage breakdown as assessed histologically and histomorphometrically.

Anti-arthritic effect of GN1, a novel synthetic analog of glucosamine, in the collagen-induced arthritis model in rats

OBJECTIVE

Glucosamine is a naturally occurring amino monosaccharide that maintains the elasticity and strength of the cartilage tissues. It has been used to treat osteoarthritis in humans; however, in severe conditions of inflammation and pain, glucosamine alone is not enough, and it is important to improve its biological activity. Our research group has recently taken an interest in the synthetic manipulation of amino sugars to develop some efficient pharmacophores, e.g., β-D-glucosamine, to combat rheumatoid arthritis, and tested its anti-arthritic effects in the collagen-induced arthritis (CIA) model in rats.

METHODS

Arthritis was induced in female Sprague-Dawley rats by multiple intradermal injections of bovine type II collagen and challenged again with the same antigen preparation 7 days later. Arthritis was evaluated by arthritic score, body weight loss, paw volume measurement, and histological changes.

RESULTS

The animals in the arthritic control group showed a gradual decrease in their body weight and concurrent increase in the paw volumes compared to the normal control group. In contrast, increased hind paw swelling was significantly suppressed with no further noticeable reduction in body weight in the glucosamine (p < 0.05) and GN1-treated (p < 0.02) arthritic animals. Histopathological evaluation of isolated knee joints by grading system and classification of the stages in arthritic lesion development revealed suppression of the inflammatory changes in the GN1-treated animals. Moreover, both the pro-inflammatory markers C-reactive protein (CRP) and low-density lipoprotein (LDL) levels were found to be significantly decreased in animals treated with GN1 (p < 0.03 for CRP and p < 0.05 for LDL) compared to the arthritic control group.

CONCLUSION

These results suggest that GN1 has both anti-arthritic and anti-inflammatory properties. Its effects in the CIA model suggest that it could be useful in the treatment of rheumatoid arthritis.

The Fate of Oral Glucosamine Traced by (13)C Labeling in the Dog

OBJECTIVE

It has remained ambiguous as to whether oral dosing of glucosamine (GlcN) would make its way to the joint and affect changes in the cartilage, particularly the integrity of cartilage and chondrocyte function. The objective of this study was to trace the fate of orally dosed GlcN and determine definitively if GlcN was incorporated into cartilage proteoglycans.

DESIGN

Two dogs were treated with (13)C-GlcN-HCl by oral dosing (500 mg/dog/d for 2 weeks and 250 mg/dog/d for 3 weeks). Cartilage was harvested from the tibial plateau and femoral condyles along with tissue specimens from the liver, spleen, heart, kidney, skin, skeletal muscle, lung, and costal cartilage. Percentages of (13)C and (13)C-GlcN present in each tissue sample were determined by inductively coupled plasma mass spectroscopy (ICP-MS) and nuclear magnetic resonance spectroscopy, respectively.

RESULTS

In the case of dog 1 (2-week treatment), there was an increase of 2.3% of (13)C present in the articular cartilage compared to the control and an increase of 1.6% of (13)C in dog 2 compared to control. As to be expected, the highest percentage of (13)C in the other tissues tested was found in the liver, and the remaining tissues had percentages of (13)C less than that of articular cartilage.

CONCLUSION

The results are definitive and for the first time provide conclusive evidence that orally given GlcN can make its way through the digestive tract and be used by chondrocytes in joint cartilage, thereby potentially having an effect on the available GlcN for proteoglycan biosynthesis.

Effects of oral glucosamine hydrochloride administration on plasma free amino acid concentrations in dogs

We examined the effects of oral glucosamine hydrochloride (GlcN), N-acetyl-d-glucosamine (GlcNAc) and d-glucose (Glc) administration on plasma total free amino acid (PFAA) concentrations in dogs. The PFAA concentrations increased in the control group and the GlcNAc group at one hour after feeding, and each amino acid concentration increased. On the other hand, in the GlcN group and the Glc group PFAA concentrations decreased at one hour after feeding. A significant decrease in amino acid concentration was observed for glutamate, glycine and alanine. Our results suggest the existence of differences in PFAA dynamics after oral administration of GlcN and GlcNAc in dogs.

Identification and quantification of glucosamine in rabbit cartilage and correlation with plasma levels by high performance liquid chromatography-electrospray ionization-tandem mass spectrometry

A new HPLC-ESI-MS/MS method for the determination of glucosamine (2-amino-2-deoxy-d-glucose) in rabbit cartilage was developed and optimized. Glucosamine was extracted from cartilage by cryogenic grinding followed by protein precipitation with trichloroacetic acid. The HPLC separation was achieved with a polymer-based amino column using a mobile phase composed of 10mM ammonium acetate (pH 7.5)-acetonitrile (20:80%, v/v) at 0.3 mL min flow rate. d-[1-(13)C]Glucosamine was used as internal standard. Selective detection was performed by tandem mass spectrometry with electrospray source, operating in positive ionization mode and in multiple reaction monitoring acquisition (m/z 180→72 and 181→73 for glucosamine and internal standard, respectively). Limit of quantification was 0.045 ng injected, corresponding to 0.25 μg g⁻¹ in cartilage. Linearity was obtained up to 20 μg g⁻¹ (R(2)>0.991). Precision values (%R.S.D.) were <10%. Accuracy (% bias) ranged from -6.0% to 12%. Mean recoveries obtained at 3 concentration levels were higher than 81% (%R.S.D.≤8%). The method was applied to measure glucosamine levels in rabbit cartilage and plasma after single oral administration of glucosamine sulfate at a dose of 98 mg kg⁻¹(n=6). Glucosamine was present in cartilage in physiological condition before the treatment. After dosing, mean concentration of cartilage glucosamine significantly increased from 461 to 1040 ng g⁻¹. Cartilage glucosamine levels resulted to be well correlated with plasma concentrations, which therefore are useful to predict the target cartilage concentration and its pharmacological activity.

The human pharmacokinetics of oral ingestion of glucosamine and chondroitin sulfate taken separately or in combination

OBJECTIVE

As part of the National Institutes of Health (NIH)-sponsored Glucosamine/Chondroitin sulfate Arthritis Intervention Trial (GAIT) our objective here was to examine (1) the pharmacokinetics (PK) of glucosamine (GlcN) and chondroitin sulfate (CS) when taken separately or in combination as a single dose in normal individuals (n=29) and (2) the PK of GlcN and CS when taken as a single dose after 3 months daily dosing with GlcN, CS or GlcN+CS, in patients with symptomatic knee pain (n=28).

METHODS

The concentration of GlcN in the circulation was determined by established fluorophore-assisted carbohydrate electrophoresis (FACE) methods. The hydrodynamic size and disaccharide composition of CS chains in the circulation and dosage samples was determined by Superose 6 chromatography and FACE.

RESULTS

We show that circulating levels of CS in human plasma are about 20 microg/ml. Most significantly, the endogenous concentration and CS disaccharide composition were not detectably altered by ingestion of CS, when the CS was taken alone or in combination with GlcN. On the other hand, the Cmax (single-dose study) and AUC values (multiple-dose study) for ingested GlcN were significantly reduced by combination dosing with CS, relative to GlcN dosing alone.

CONCLUSIONS

We conclude that pain relief perceived following ingestion of CS probably does not depend on simultaneous or prior intake of GlcN. Further, such effects on joint pain, if present, probably do not result from ingested CS reaching the joint space but may result from changes in cellular activities in the gut lining or in the liver, where concentrations of ingested CS, or its breakdown products, could be substantially elevated following oral ingestion. Moreover, since combined dosing of GlcN with CS was found to reduce the plasma levels seen with GlcN dosing alone, any improved pain relief by combination dosing cannot be explained by higher circulating concentrations of GlcN.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Oral glucosamine modulates the response of the liver and lymphocytes of the mesenteric lymph nodes in a papain-induced model of joint damage and repair

OBJECTIVES

To assess whether glucosamine (GlcN), an oral supplement commonly taken to relieve the symptoms of osteoarthritis, modulates the immune and inflammatory responses to joint injury in organs proximal to GlcN absorption; namely, the liver and the gut-draining lymph nodes.

METHOD

Using a papain-injected knee mouse model, standard histological methods were used to validate our model and document the impact of GlcN (100mg/kg/day) on groups of C57BL/6 mice (n=5). Circulating inflammatory cytokines were assessed by Luminex-based immunoassays and the relevance of this cytokine profile on proteoglycan biosynthesis evaluated using a patellar-cartilage assay. Real-time PCR was used to document the role of the liver in cytokine production. Finally, we appraised the activation of mesenteric lymph nodes (MLNs) lymphocytes by flow cytometry.

RESULTS

Papain significantly degraded the proteoglycans in the injected knees by 2 days. Cartilage proteoglycan content was significantly higher in GlcN-treated, papain-injected knees at Day 14. The peak concentration of serum pro-inflammatory cytokines occurred earlier and decreased sooner in the injected, GlcN-supplemented mice; this trend was in agreement with the expression of these factors by the liver. GlcN did not alter the percentage of MLN populations but accelerated their activation.

CONCLUSIONS

Oral GlcN alters the physiology of the liver and MLNs, which in turn, could indirectly alter the biology of the injured joint.

Development and validation of a HPLC-ES-MS/MS method for the determination of glucosamine in human synovial fluid

A new HPLC method for the determination of glucosamine (2-amino-2-deoxy-D-glucose) in human synovial fluid was developed and validated. Synovial fluid samples were analyzed after a simple protein precipitation step with trichloroacetic acid using a polymer-based amino column with a mobile phase composed of 10 mM ammonium acetate (pH 7.5)-acetonitrile (20:80, v/v) at 0.3 mL/min flow rate. D-[1-13C]glucosamine was used as internal standard. Selective detection was performed by tandem mass spectrometry with electrospray source, operating in positive ionization mode and in multiple reaction monitoring acquisition (m/z 180-->72 and 181-->73 for glucosamine and internal standard, respectively). The limit of quantification (injected volume=3 microL) was 0.02 ng, corresponding to 10 ng/mL in synovial fluid. Calibration curves obtained using matrix-matched calibration standards and internal standard at 600 ng/mL were linear up to 2000 ng/mL. Precision values (%R.S.D.) were < or = 14% in the entire analytical range. Accuracy (%bias) ranged from -11% to 10%. The recoveries measured at three concentration levels (50, 800, and 1500 ng/mL) were higher than 89%. The method was successfully applied to measure endogenous glucosamine levels in synovial fluid samples collected from patients with knee osteoarthritis and glucosamine levels after oral administration of glucosamine sulfate (DONA) at the dose of 1500 mg/day for 14 consecutive days (steady-state).