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

Molecular Fingerprint of Human Pathological Synoviocytes in Response to Extractive Sulfated and Biofermentative Unsulfated Chondroitins

Pharma-grade extractive chondroitin sulfate (CS) is widely used for osteoarthritis (OA) treatment. Recently, unsulfated biofermentative chondroitin (BC) proved positive effects in OA in vitro model. This study, based on primary pathological human synoviocytes, aimed to analyze, by a multiplex assay, a panel of OA-related biomarkers in response to short-term treatments with bovine (CS_b), pig (CS_p) and fish (CS_f) chondroitins, in comparison to BC. As expected, all samples had anti-inflammatory properties, however CS_b, CS_f and especially BC affected more cytokines and chemokines. Based on these results and molecular weight similarity, CS_f and BC were selected to further explore the synoviocytes' response. In fact, Western blot analyses showed CS_f and BC were comparable, downregulating OA-related biomarkers such as the proteins mTOR, NF-kB, PTX-3 and COMP-2. Proteomic analyses, performed by applying a nano-LC-MS/MS TMT isobaric labelling-based approach, displayed the modulation of both common and distinct molecules to chondroitin treatments. Thus, CS_f and BC modulated the biological mediators involved in the inflammation cascade, matrix degradation/remodeling, glycosaminoglycans' synthesis and cellular homeostasis. This study helps in shedding light on different molecular mechanisms related to OA disease that may be potentially affected not only by animal-source chondroitin sulfate but also by unsulfated biofermentative chondroitin.

Dietary supplementation with glycosaminoglycans reduces locomotor problems in broiler chickens

This study aimed to assess the influence of glycosaminoglycan (chondroitin and glucosamine sulfates) supplementation in the diet on the performance and incidence of locomotor problems in broiler chickens. A completely randomized design was carried out in a 3 × 3 factorial scheme (3 levels of chondroitin sulfate -0, 0.05, and 0.10%; and 3 levels of glucosamine sulfate -0, 0.15, and 0.30%). Each treatment was composed of 6 replications of 30 broilers each. The performance of broilers (average weight, weight gain, feed intake, feed conversion, and productive viability) was assessed at 7, 21, 35, and 42 d of age, whereas the gait score, valgus and varus deviations, femoral degeneration, and tibial dyschondroplasia were assessed at 21 and 42 d of age. Increasing levels of glucosamine sulfate inclusion linearly increased the weight gain from 1 to 35 and from 1 to 42 d of age of broilers (P = 0.047 and P = 0.039, respectively), frequency of broilers with no femoral degeneration in the right and left femurs, and the proliferating cartilage area of proximal epiphysis at 42 d of age (P = 0.014, P < 0.0001, and P = 0.028, respectively). The increasing inclusion of chondroitin and glucosamine sulfates led to an increase in the frequency of broilers on the gait score scale 0 (P = 0.007 and P = 0.0001, respectively) and frequency of broilers with no valgus and varus deviations (P = 0.014 and P = 0.0002, respectively) also at 42 d of age. Thus, chondroitin and glucosamine sulfates can be used in the diet of broiler chickens to reduce their locomotor problems.

Effect of glucosamine and chondroitin sulfate in symptomatic knee osteoarthritis: a systematic review and meta-analysis of randomized placebo-controlled trials

Although glucosamine and chondroitin sulfate have showed beneficial effects on joint tissues in osteoarthritis (OA), their therapeutic use in the clinical setting is still debatable. Hence, a systematic review and meta-analysis of randomized placebo-controlled trials was conducted to investigate the efficacy of glucosamine and chondroitin sulfate on knee OA symptoms. Medline, SCOPUS, Web of Science, and Google Scholar databases were searched for randomized placebo-controlled trials evaluating the effect of orally administered glucosamine and/or chondroitin sulfate on OA symptoms using the Western Ontario and McMaster Universities Osteoarthritis index (WOMAC) and/or the Visual Analog Scale (VAS). Meta-analysis was conducted using a random-effects model and generic inverse-variance method. Heterogeneity was tested using the I2 statistic index. Treatments with glucosamine and chondroitin were found to significantly reduce pain in VAS [weighted mean difference (WMD) - 7.41 mm, 95% CI - 14.31, - 0.51, p = 0.04 and WMD - 8.35 mm, 95% CI - 11.84, - 4.85, p < 0.00001, respectively]. Their combination did not show this behavior (WMD - 0.28 mm, 95% CI - 8.87, 8.32, p = 0.95). None of the glucosamine, chondroitin or their combination had a significant positive effect on the total WOMAC index and its subscores. Oral supplementation with glucosamine or chondroitin sulfate reduces pain in knee OA. However, there is no additional effect using both therapeutic agents in combination for the management of symptomatic knee OA.

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.

In Vivo Detection of the Effect of Electroacupuncture on "Zusanli" Acupoint in Rats with Adjuvant-Induced Arthritis through Optical Coherence Tomography

This study aimed to investigate the effect of electroacupuncture (EA) treatment through optical coherence tomography (OCT) in vivo on rats with adjuvant-induced arthritis. OCT images were obtained from the ankle of the right hind paws of the rats in control, model, and EA groups before modelling and 1 day, 8 days, 15 days, 22 days, and 29 days after modelling. Results demonstrated that the OCT signal of the ankle of the right hind paws of the rats was indistinct compared to 1 day after modelling and before modelling in the EA group. In the EA group, the light averaged attenuation coefficients of the ankle tissues decreased as treatment duration was prolonged after EA was administered (3.43, 2.96, 2.61, 2.42, and 2.29 mm⁻¹, resp.). There was a significant difference in attenuation coefficient decrease between the 29th d and the 1st d for EA group compared with control group (P < 0.01). This condition indicated that the light absorption of the ankle of the treated rats in the EA group decreased. Therefore, OCT can be used to monitor the effect of treatment on rats with arthritis in vivo.

Importance of synovitis in osteoarthritis: evidence for the use of glycosaminoglycans against synovial inflammation

OBJECTIVES

After detailing the different aspects of synovial inflammation (i.e., cellular, biochemical, and vascular) and based on the current knowledge, the aim of this review was to collect the available in vitro and in vivo data regarding the potency of some glycosaminoglycan (GAG) compounds to target synovial inflammation, an important aspect of osteoarthritis.

METHODS

The first part of the review corresponds to a qualitative review of the inflammatory status of OA synovial membrane. The second part corresponds to a systematic review of the literature regarding the potential effects of some GAGs on the previously described phenomenon.

RESULTS

The synovial aspect of the inflammatory status of OA has been detailed. Chondroitin sulfate has demonstrated to control the three aspects of synovial membrane inflammation: cell infiltration and activity, biochemical mediators release, and angiogenesis. Glucosamine is also active on both cellular and molecular aspects of the inflammatory reaction. Hyaluronic acid seems to be anti-inflammatory in its native form, while products of degradation are reported to be pro-angiogenic.

CONCLUSION

Much evidence suggests that some of the studied GAG compounds could target different aspects of synovitis. Some of them could be considered in combination therapy since they exhibit complementary properties. Most of the studies have concentrated on articular cartilage and chondrocytes. In order to achieve a structure modification, one may now consider all joint tissues and investigate the drug potency on all of them. Potent treatment should trigger the most important features of OA: cartilage degradation, subchondral bone sclerosis, and all aspects of synovial inflammation.

The anti-arthritic and immune-modulatory effects of NHAG: a novel glucosamine analogue in adjuvant-induced arthritis

Rheumatoid arthritis (RA) is potentially devastating condition which lacks good treatment options. Pro-inflammatory cytokines interleukin-1beta (IL-1β), tumor necrosis factor-alpha (TNF-α), and oxidative stress markers such as nitric oxide (NO) and peroxide (PO) are mediators of RA pathogenesis. In the present study N-[2,4,5-trihydroxy-6-(hydroxymethyl) tetrahydro-2H-pyran-3-yl]acrylamide (NHAG), analogue of glucosamine, was evaluated in adjuvant-induced arthritic model of rats. The disease progression was monitored by analysing arthritis scoring, loss of body weight, paw oedema, and histological changes in joints. RA associated hyperalgesia was evaluated by gait analysis. The serum or plasma levels of NO, PO, glutathione (GSH) superoxide dismutase (SOD) IL-1β and TNF-α were analyzed to monitor the state of disease severity. The arthritic control animals exhibited significant increase in arthritic score (P < 0.003) and paw oedema (P < 0.001) with parallel loss in body weight (P < 0.04). The NHAG-treated arthritic animals exhibited refinement in the gait changes associated with arthritis. NHAG also significantly decreased the NO (P < 0.02) and PO (P < 0.03) with concurrent increased in GSH (P < 0.04) and SOD (P < 0.007). Both IL-1β (P < 0.001) and TNF-α (P < 0.001), were significantly decreased in NHAG-treated group. Thus NHAG might have a therapeutic potential for arthritis by exerting antioxidative and immunomodulatory effects.

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

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

Use of glucosamine and chondroitin in persons with osteoarthritis

Glucosamine and chondroitin are members of a group of dietary supplements often termed "complementary agents," "disease-modifying agents," or "disease-modifying osteoarthritis drugs" (DMOADs). They are among the best-selling dietary supplements in the United States. DMOADs are thought to act by affecting cytokine-mediated pathways regulating inflammation, cartilage degradation, and immune responses. Given the results of recent studies, investigators have begun to question whether the popular combination of glucosamine and chondroitin alleviates disease progression or pain in people with mild to moderate knee osteoarthritis. Reasons proposed for the lack of benefit include incorrect dosing, suboptimal compound manufacture, and a lack of complete understanding of when and how to apply the compounds. In addition, adjuvant medications also could augment the therapeutic potential of these agents. Although these agents are considered safe, some uncommon and minor adverse effects have been reported, including epigastric pain or tenderness (3.5%), heartburn (2.7%), diarrhea (2.5%), and nausea (1%). In conclusion, although some questions have arisen about whether DMOADs are as effective as has been claimed, a trial should be considered in in selected patients with sustained refractory cases of osteoarthritis.