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

MicroRNA as Possible Mediators of the Synergistic Effect of Celecoxib and Glucosamine Sulfate in Human Osteoarthritic Chondrocyte Exposed to IL-1β

This study investigated the role of a pattern of microRNA (miRNA) as possible mediators of celecoxib and prescription-grade glucosamine sulfate (GS) effects in human osteoarthritis (OA) chondrocytes. Chondrocytes were treated with celecoxib (1.85 µM) and GS (9 µM), alone or in combination, for 24 h, with or without interleukin (IL)-1β (10 ng/mL). Cell viability was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, apoptosis and reactive oxygen species (ROS) by cytometry, nitric oxide (NO) by Griess method. Gene levels of miRNA, antioxidant enzymes, nuclear factor erythroid (NRF)2, and B-cell lymphoma (BCL)2 expressions were analyzed by quantitative real time polymerase chain reaction (real time PCR). Protein expression of NRF2 and BCL2 was also detected at immunofluorescence and western blot. Celecoxib and GS, alone or in combination, significantly increased viability, reduced apoptosis, ROS and NO production and the gene expression of miR-34a, -146a, -181a, -210, in comparison to baseline and to IL-1β. The transfection with miRNA specific inhibitors significantly counteracted the IL-1β activity and potentiated the properties of celecoxib and GS on viability, apoptosis and oxidant system, through nuclear factor (NF)-κB regulation. The observed effects were enhanced when the drugs were tested in combination. Our data confirmed the synergistic anti-inflammatory and chondroprotective properties of celecoxib and GS, suggesting microRNA as possible mediators.

Effect of glycosaminoglycans on the structure and composition of articular cartilage and bone of broilers

This study aimed to assess the influence of glycosaminoglycan (chondroitin and glucosamine sulfates) supplementation in the diet of broilers on the expression of matrix metallopeptidase 9 (MMP-9) and metallopeptidase inhibitor 2 (TIMP-2) genes, the synthesis of proteoglycans, collagen type II and chondrocytes, bone and cartilage macroscopy, bone mineral densitometry, bone breaking strength and mineral profile. A completely randomized design was carried out in a 3 × 3 factorial scheme (3 levels of chondroitin sulfate: 0.00, 0.05, and 0.10%; and 3 levels of glucosamine sulfate: 0.00, 0.15, and 0.30%), totaling 9 treatments. At 21 and 42 d of age, broilers were slaughtered, and tibias and femurs were collected for evaluation. There was an interaction (P < 0.05) of sulfates for the expression of MMP-9 and its inhibitor TIMP-2 in femur articular cartilage, as well as for the number of chondrocytes, collagen type II and proteoglycans in tibia articular cartilage, bone and cartilage macroscopy and mineral profile (P < 0.05), with better results obtained with the inclusion of chondroitin and/or glucosamine sulfates in the feed. In conclusion, chondroitin and glucosamine sulfates can be used in broiler diets in order to favor the development of the structure of the locomotor system (bones and joints), thus preventing locomotion problems.

Drug Screening Implicates Chondroitin Sulfate as a Potential Longevity Pill

Discovering compounds that promote health during aging ("geroprotectors") is key to the retardation of age-related pathologies and the prevention of chronic age-related diseases. In in-silico and model organisms' lifespan screens, chondroitin sulfate has emerged as a geroprotective compound. Chondroitin sulfate is a glycosaminoglycan attached to extracellular matrix proteins and is naturally produced by our body. Oral supplementation of chondroitin sulfate shows a high tolerance in humans, preferable pharmacokinetics, a positive correlation with healthy human longevity, and efficacy in deceleration of age-related diseases in randomized clinical trials. We have recently shown that chondroitin sulfate supplementation increases the lifespan of C. elegans. Thus, chondroitin sulfate holds the potential to become a geroprotective strategy to promote health during human aging. This review discusses the two major potential mechanisms of action, extracellular matrix homeostasis and inhibition of inflammation, that counteract age-related pathologies upon chondroitin sulfate supplementation.

Proteomic Analysis of Synovial Fibroblasts and Articular Chondrocytes Co-Cultures Reveals Valuable VIP-Modulated Inflammatory and Degradative Proteins in Osteoarthritis

Osteoarthritis (OA) is the most common musculoskeletal disorder causing a great disability and a reduction in the quality of life. In OA, articular chondrocytes (AC) and synovial fibroblasts (SF) release innate-derived immune mediators that initiate and perpetuate inflammation, inducing cartilage extracellular matrix (ECM) degradation. Given the lack of therapies for the treatment of OA, in this study, we explore biomarkers that enable the development of new therapeutical approaches. We analyze the set of secreted proteins in AC and SF co-cultures by stable isotope labeling with amino acids (SILAC). We describe, for the first time, 115 proteins detected in SF-AC co-cultures stimulated by fibronectin fragments (Fn-fs). We also study the role of the vasoactive intestinal peptide (VIP) in this secretome, providing new proteins involved in the main events of OA, confirmed by ELISA and multiplex analyses. VIP decreases proteins involved in the inflammatory process (CHI3L1, PTX3), complement activation (C1r, C3), and cartilage ECM degradation (DCN, CTSB and MMP2), key events in the initiation and progression of OA. Our results support the anti-inflammatory and anti-catabolic properties of VIP in rheumatic diseases and provide potential new targets for OA treatment.

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.

Nonsurgical Management of Cartilage Defects of the Knee: Who, When, Why, and How?

The nonoperative practitioner managing individuals with cartilage defects should use a patient-centered, multifaceted approach that aims to individualize treatment to provide optimal benefit. These include addressing modifiable risk factors for disease progression and instituting interventions such as weight loss, nutrition, physical activity, and potentially regenerative medicine strategies. This review will focus on these nonoperative treatment strategies with a focus on when treatments are necessary, who will benefit from these approaches, why they are specifically appropriate, and, finally, how these treatments directly modify the structure of a patient's cartilage and resulting symptoms.

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

Background:

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

Materials and Methods:

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

Results:

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

Conclusion:

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

Lentinan Inhibits AGE-Induced Inflammation and the Expression of Matrix-Degrading Enzymes in Human Chondrocytes

Background

Chondrocyte-mediated inflammation is an important pathological component of osteoarthritis (OA) development. There are currently no therapies that completely reverse the development of OA. Lentinan, a type of polysaccharide derived from Lentinus edodes, has been demonstrated to possess significant anti-viral, anti-cancer, and anti-inflammatory effects, and has been recently used in the treatment of several inflammatory diseases. However, little research has focused on the pharmacological effect of lentinan in human OA.

Materials and Methods

We evaluated the anti-inflammatory and anti-ROS effects of lentinan in SW1353 chondrocytes treated with AGEs using real-time polymerase chain reaction (PCR), enzyme-linked immunosorbent assay (ELISA), and the nitro oxide-specific stain DAF-FM DA. The regulatory effects of lentinan on NF-κB and MAPK p38 signaling were investigated via promoter assay and Western blot analysis.

Results

We found that lentinan inhibits the production of pro-inflammatory cytokines, including IL-1β, TNF-α, IL-8 and the secretion of PGE₂ and NO, by reducing the expression of COX-2 and iNOS in AGE-challenged chondrocytes. Lentinan also reduces AGE-induced increased expression of matrix metalloproteinases-1, −3, and −13 (MMP-1, MMP-3, MMP-13). Furthermore, lentinan has a similar effect on a disintegrin and metalloproteinase with thrombospondin motifs-4 and −5 (ADAMTS-4, ADAMTS-5). Mechanistically, lentinan reduces the activation of NF-κB.

Conclusion

Our findings indicate that lentinan shows a protective effect against AGE-induced inflammatory response in chondrocytes. These findings suggest that lentinan is a promising agent for the treatment of OA that could be used as a dietary supplement for patients with OA.

Differential Secretome Profiling of Human Osteoarthritic Synoviocytes Treated with Biotechnological Unsulfated and Marine Sulfated Chondroitins

Symptomatic slow-acting drugs (SYSADOA) are increasingly used as effective therapies for osteoarthritis, representing an attractive alternative to analgesics or non-steroidal anti-inflammatory drugs to relieve disease symptoms. Pharmaceutical preparations of chondroitin sulfate, derived from animal sources, alone or in combination with glucosamine sulfate, are widely recognized for their beneficial effect on osteoarthritis treatment. A growing interest has also been devoted to understanding the molecular mechanisms modulated by SYSADOA using -omic strategies, most of which rely on chondrocytes as a model system. In this work, by using an integrated strategy based on unbiased proteomics and targeted cytokine profiling by a multiplexed protein array, we identified differences in the secretomes of human osteoarthritic synoviocytes in response to biotechnological unsulfated, and marine sulfated chondroitins treatments. The combined strategy allowed the identification of candidate proteins showing both common and distinct regulation responses to the two treatments of chondroitins. These molecules, mainly belonging to ECM proteins, enzymes, enzymatic inhibitors and cytokines, are potentially correlated to treatment outcomes. Overall, the present results provide an integrated overview of protein changes in human osteoarthritic synoviocytes secretome associated to different chondroitin treatments, thus improving current knowledge of the biochemical effects driven by these drugs potentially involved in pathways associated to osteoarthritis pathogenesis.

Topical application of Chinese herbal medicine DAEP relieves the osteoarthritic knee pain in rats

Background

The potential adverse effects of conventional oral pharmacotherapy of osteoarthritis (OA) restrict their long-term use. Topical application of a Chinese herbal paste for relieving OA knee pain can be effective and safe. However, evidence-based scientific research is insufficient to support its application worldwide. The aim of this study was to investigate the in vivo efficacy of a topical Chinese herbal paste on relieving OA knee pain and its underlying mechanism.

Methods

An OA rat model was developed by anterior cruciate ligament transection (ACLT) followed by treadmill running. A herbal paste including Dipsaci Radix, Achyranthis Bidentatae Radix, Eucommiae Cortex and Psoraleae Fructus, named as DAEP, was applied topically on the knee joint of the rats (DAEP). The rats without DAEP treatment served as Control. Rats with surgery but without ACLT, treadmill running and DAEP treatment acted as Sham. The morphologic change of the knee joint was observed radiographically. Nociception from the knee of the rats was assessed using Incapacitent test and CatWalk gait system. The therapeutic mechanism was investigated by analyzing the gene and protein expression of inflammatory markers via qPCR and Western blot, respectively.

Results

Radiographic images showed less destruction at the posterior tibial plateau of the DAEP group compared with the Control after 2 weeks of treatment. The static weight ratio and the gait parameters of the Control were reduced significantly via Incapacitance test and CatWalk gait analysis, respectively. DAEP treatment increased the Print Area and Maximum Intensity significantly compared with the Control. DAEP significantly suppressed the upregulation of gene expression of interleukin (IL)-6, tumor necrosis factor (TNF)-α, and inducible nitric oxide synthase (iNOS).

Conclusions

DAEP exhibited its effect via the nuclear factor (NF)-κB pathway by suppressing the phosphorylation of IκB kinase αβ (p-IKKαβ) and cyclooxygenase-2 (COX-2) protein expression. This study provides scientific evidence to support the clinical application of the Chinese herbal paste on reliving OA pain.

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

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

Comparative Analyses of Pharmaceuticals or Food Supplements Containing Chondroitin Sulfate: Are Their Bioactivities Equivalent?

Introduction

Oral supplementation of chondroitin sulfate (CS) and glucosamine (GlcN), symptomatic slow-acting molecules, is recommended by European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis and Musculoskeletal Diseases (ESCEO) and other European Union (EU) guidelines for the restoration of the articular cartilage surface in patients affected by osteoarthritis (OA). They are commercialized as pharmaceutical grade products and as food supplements in combination with plant extracts hyaluronic acid, methylsulfonylmethane, and other components. Food supplements do not need to undergo the strict regulatory controls of pharmaceutical grade products; thus, composition and contaminants that could be present may not be evidenced before commercialization and these uncertainties may give rise to concerns about the bioactivity of these formulations.

Methods

In this paper 10 different food supplements (FS) from diverse European countries were analyzed in comparison with two pharmaceutical grade products (Ph) using updated analytical approaches and biochemical cell-based assays. The purity, the titer, and the origin of CS in Ph and FS samples were initially assessed in order to successively compare the biological function. Both food supplements and pharmaceutical formulations were tested in vitro, using the same final CS concentration, on primary chondrocytes and synoviocytes in terms of (i) cell viability, (ii) activation of the NF-κB-mediated inflammation pathway, (iii) cartilage oligomeric matrix protein (COMP-2), IL-6, and IL-8 production.

Results

All the FS presented a certain insoluble fraction; the CS and the GlcN contents were lower than the declared ones in 9/10 and 8/10 samples, respectively. All FS contained keratan sulfate (KS) at up to 50% of the total glycosaminoglycan amount declared on the label. Primary cells treated with the samples diluted to present the same CS concentration in the medium showed cytotoxicity in 7/10 FS while Ph preserved viability and reduced NF-κB, COMP-2, and secreted inflammatory cytokines.

Conclusion

Among all samples tested, the pharmaceutical grade products demonstrated effective modulation of biomarkers counteracting the inflammation status and improving viability and the physiological condition of OA human primary chondrocyte and synoviocyte cells. In contrast to that, most FS were cytotoxic at the tested concentrations, and only 3/10 of them showed similarities to Ph sample behavior in vitro.

Funding

This work was partially supported by PON01_1226 NUTRAFAST, MIUR Ministero dell’Università e della Ricerca Scientifica. Bioteknet financed two short-term grants for graduate technicians. The journal’s Rapid Service and Open Access fees were funded by IBSA CH.

Enhanced chondrogenic differentiation of bone marrow mesenchymal stem cells on gelatin/glycosaminoglycan electrospun nanofibers with different amount of glycosaminoglycan

Tissue engineering is a new technique to help damaged cartilage treatment using cells and scaffolds. In this study we tried to evaluate electrospun scaffolds composed of gelatin/glycosaminoglycan (G/GAG) blend nanofibers in chondrogenesis of bone marrow-derived mesenchymal stem cells (BMMSCs). Scaffolds were fabricated by electrospinning technique with different concentration of glycosaminoglycan (0%, 5%, 10%, and 15%) in gelatin matrix. BMMSCs were cultured on the scaffolds for chondrogenesis process. MTT assay was done for scaffold's biocompatibility and cells viability evaluation. Alcian blue staining was carried out to determine the release of GAG and reverse transcription polymerase chain reaction (RT-PCR) was done for expression of COL2A1 and also immunocytochemistry assay were used to confirm expression of type II collagen. Scaffold with 15% GAG showed better result for biocompatibility (p =0.02). Scanning electron microscopy (SEM) micrographs showed that MSCs have good attachment to the scaffolds. Alcian blue staining result confirmed that cells produce GAG during differentiation time different from GAG in the scaffolds. Also the results for RT-PCR showed the expression of COL2A1 marker. Immunocytochemistry assay for type II collagen confirm that this protein expressed. Scaffold comprising 15% GAG is better results for chondrogenesis and it can be a good applicant for cartilage tissue engineering. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 38-48, 2019.

Effectiveness of a Dietary Supplement Containing Hydrolyzed Collagen, Chondroitin Sulfate, and Glucosamine in Pain Reduction and Functional Capacity in Osteoarthritis Patients

This observational, open, multicenter clinical trial with a single treatment group aimed to evaluate the effectiveness of a dietary supplement whose main ingredients are hydrolyzed gelatin, chondroitin sulfate, glucosamine sulfate, and devil's claw and bamboo extracts for pain reduction and improvement of functional capacities in patients with osteoarthritis (OA) of the knee and/or hip (REDART study). In all, 130 patients with OA recruited from Spanish hospitals received the dietary supplement for 6 months. The primary outcome was the patients' global assessment of pain in the affected joint as measured with a visual analogue scale (VAS). Other outcome measurements included the Lequesne Functional Index (subindexes for pain/discomfort, distance walked, and daily living) and the Western Ontario and McMaster Universities Arthritis Index (WOMAC; subindexes for pain, stiffness, and physical function). Scores were taken at months 3 and 6 of the treatment. Patients (N = 78) showed a reduction of pain of 3.77 ± 1.77 points after 6 months (p < .0001) in the VAS. The total reduction in the Lequesne Functional Index was 6.30 ± 4.08 points after 6 months (p < .0001), with significant reductions in all subindexes of the scale. A similar pattern was found for the WOMAC index, with an overall reduction of 22.49 ± 14.03 points after 6 months (p < .0001) and significant reductions in all subindexes. No major adverse events were noted during the treatment. This exploratory study shows that treatment with the dietary supplement significantly reduces pain and improves locomotor function in patients with OA of the knee and/or hip.

Chondroitin Sulfate Inhibits Monocyte Chemoattractant Protein-1 Release From 3T3-L1 Adipocytes: A New Treatment Opportunity for Obesity-Related Inflammation?

Monocyte chemoattractant protein-1 (MCP-1) overproduction from inflamed adipose tissue is a major contributor to obesity-related metabolic syndromes. 3T3-L1 embryonic fibroblasts were cultured and differentiated into adipocytes using an established protocol. Adipocytes were treated with lipopolysaccharide (LPS) to induce inflammation and thus MCP-1 release. At the same time, varying concentrations of chondroitin sulfate (CS) were added in a physiologically relevant range (10-200 µg/mL) to determine its impact on MCP-1 release. Chondroitin sulfate, a natural glycosaminoglycan of connective tissue including the cartilage extracellular matrix, was chosen on the basis of our previous studies demonstrating its anti-inflammatory effect on macrophages. Because the main action of MCP-1 is to induce monocyte migration, cultured THP-1 monocytes were used to test whether CS at the highest physiologically relevant concentration could inhibit cell migration induced by human recombinant MCP-1. Chondroitin sulfate (100-200 µg/mL) inhibited MCP-1 release from inflamed adipocytes in a dose-dependent manner (P < .01, 95% confidence interval [CI]: −5.89 to −3.858 at 100 µg/mL and P < .001, 95% CI: −6.028 to −3.996 at 200 µg/mL) but had no effect on MCP-1–driven chemotaxis of THP-1 monocytes. In summary, CS could be expected to reduce macrophage infiltration into adipose tissue by reduction in adipocyte expression and release of MCP-1 and as such might reduce adipose tissue inflammation in response to pro-inflammatory stimuli such as LPS, now increasingly recognized to be relevant in vivo.

Glucosamine has an antiallergic effect in mice with allergic asthma and rhinitis

BACKGROUND

Glucosamine (GlcN) is generally used as a dietary supplement because of its antiinflammatory effects. We evaluated the antiallergic effect of GlcN in mice with allergic asthma and rhinitis.

METHODS

Thirty-two mice were allocated equally into 4 groups (n = 8). In group A (control), we performed intraperitoneal/intranasal challenge using sterile saline. In group B (asthma/rhinitis), we used ovalbumin for intraperitoneal/intranasal challenge to induce allergic asthma and rhinitis. In groups C and D (GlcN treatment), mice were given 1% and 5% GlcN throughout the period of ovalbumin challenge, respectively. We measured serum total and ovalbumin-specific immunoglobulin E (IgE), cytokine titers (interleukin-1, -4, -5, -6, -10, and -17; tumor necrosis factor-α; and interferon-γ), and the number of inflammatory cells (eosinophils, neutrophils, lymphocytes) in bronchoalveolar lavage (BAL) fluid. We also performed histopathologic examination of the lung and nasal cavity. Finally, we performed real-time polymerase chain reaction for the genes Bcl-2, EC-SOD, VEGF, caspase-3, Bax, COX-2, Hif-1α, and heme oxygenase-1.

RESULTS

Compared with group B, group D had significant serum total and ovalbumin-specific IgE decreases after GlcN treatment (p < 0.05). Titers for IL-4, IL-5, IL-6, and IL-17 in BAL fluid were significantly decreased in group D (p < 0.05). Eosinophils in BAL fluid were significantly decreased in group D compared with group B (p < 0.05). Groups C and D showed significant improvement of inflammation compared with group B. Group D had significant downregulation of EC-SOD, Bax, Hif-1α, and heme oxygenase-1 compared with group B.

CONCLUSION

GlcN had a significant antiallergic effect in mice with allergic asthma and rhinitis.

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

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

Glucosamine and chondroitin for the treatment of osteoarthritis

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

Biotechnological Chondroitin a Novel Glycosamminoglycan With Remarkable Biological Function on Human Primary Chondrocytes

Cartilage tissue engineering, with in vitro expansion of autologus chondrocytes, is a promising technique for tissue regeneration and is a new potential strategy to prevent and/or treat cartilage damage (e.g., osteoarthritis). The aim of this study was (i) to investigate and compare the effects of new biotechnological chondroitin (BC) and a commercial extractive chondroitin sulfate (CS) on human chondrocytes in vitro culture; (ii) to evaluate the anti‐inflammatory effects of the innovative BC compared to extractive CS. A chondrogenic cell population was isolated from human nasoseptal cartilage and in vitro cultures were studied through time‐lapse video microscopy (TLVM), immunohistochemical staining and cytometry. In order to investigate the effect of BC and CS on phenotype maintainance, chondrogenic gene expression of aggrecan (AGN), of the transcriptor factor SOX9, of the types I and II collagen (COL1A1 and COL1A2), were quantified through transcriptional and protein evaluation at increasing cultivation time and passages. In addition to resemble the osteoarthritis‐like in vitro model, chondrocytes were treated with IL‐1β and the anti‐inflammatory activity of BC and CS was assessed using cytokines quantification by multiplex array. BC significantly enhances cell proliferation also preserving chondrocyte phenotype increasing type II collagen expression up to 10 days of treatment and reduces inflammatory response in IL‐1β treated chondrocytes respect to CS treated cells. Our results, taken together, suggest that this new BC is of foremost importance in translational medicine because it can be applied in novel scaffolds and pharmaceutical preparations aiming at cartilage pathology treatments such as the osteoarthritis. J. Cell. Biochem. 117: 2158–2169, 2016. © 2016 The Authors. Journal of Cellular Biochemistry Published by Wiley Periodicals, Inc.

Molecular mechanisms and biomedical applications of glucosamine as a potential multifunctional therapeutic agent

Glucosamine and its acetylated derivative, N-acetyl glucosamine, are naturally occurring amino sugars found in human body. They are important components of glycoproteins, proteoglycans and glycosaminoglycans. Scientific studies have supported that glucosamine has the beneficial pharmacological effects to relieve osteoarthritis symptoms. Glucosamine can also be as a promising candidate for the prevention and/or treatment of some other diseases due to its anti-oxidant and anti-inflammatory activities. Most of its function is exerted by modulation of inflammatory responses especially through Nuclear Factor-κB (NF-κB) that can control inflammatory cytokine production and cell survival. In this review, we present a concise update on additional new therapeutic applications of glucosamine including treatment of cardiovascular disease, neurological deficits, skin disorders, cancer and the molecular mechanistic rationale for these uses. This article will also examine safety profile and adverse effects of glucosamine in human.

Lessons from the proteomic study of osteoarthritis

Osteoarthritis is the most common rheumatic pathology and one of the leading causes of disability worldwide. It is a very complex disease whose etiopathogenesis is not fully understood. Furthermore, there are serious limitations for its management, since it lacks specific and sensitive biomarkers for early diagnosis, prognosis and therapeutic monitoring. Proteomic approaches performed in the last few decades have contributed to the knowledge on the molecular mechanisms that participate in this pathology and they have also led to interesting panels of putative biomarker candidates. In the next few years, further efforts should be made for translating these findings into the clinical routines. It is expected that targeted proteomics strategies will be highly valuable for the verification and qualification of biomarkers of osteoarthritis.

The Spanish biology/disease initiative within the human proteome project: Application to rheumatic diseases

The Spanish Chromosome 16 consortium is integrated in the global initiative Human Proteome Project, which aims to develop an entire map of the proteins encoded following a gene-centric strategy (C-HPP) in order to make progress in the understanding of human biology in health and disease (B/D-HPP). Chromosome 16 contains many genes encoding proteins involved in the development of a broad range of diseases, which have a significant impact on the health care system. The Spanish HPP consortium has developed a B/D platform with five programs focused on selected medical areas: cancer, obesity, cardiovascular, infectious and rheumatic diseases. Each of these areas has a clinical leader associated to a proteomic investigator with the responsibility to get a comprehensive understanding of the proteins encoded by Chromosome 16 genes. Proteomics strategies have enabled great advances in the area of rheumatic diseases, particularly in osteoarthritis, with studies performed on joint cells, tissues and fluids.

BIOLOGICAL SIGNIFICANCE

In this manuscript we describe how the Spanish HPP-16 consortium has developed a B/D platform with five programs focused on selected medical areas: cancer, obesity, cardiovascular, infectious and rheumatic diseases. Each of these areas has a clinical leader associated to a proteomic investigator with the responsibility to get a comprehensive understanding of the proteins encoded by Chromosome 16 genes. We show how the Proteomic strategy has enabled great advances in the area of rheumatic diseases, particularly in osteoarthritis, with studies performed on joint cells, tissues and fluids. This article is part of a Special Issue entitled: HUPO 2014.

Combined chondroitin sulfate and glucosamine for painful knee osteoarthritis: a multicentre, randomised, double-blind, non-inferiority trial versus celecoxib

Objectives

To compare the efficacy and safety of chondroitin sulfate plus glucosamine hydrochloride (CS+GH) versus celecoxib in patients with knee osteoarthritis and severe pain.

Methods

Double-blind Multicentre Osteoarthritis interVEntion trial with SYSADOA (MOVES) conducted in France, Germany, Poland and Spain evaluating treatment with CS+GH versus celecoxib in 606 patients with Kellgren and Lawrence grades 2–3 knee osteoarthritis and moderate-to-severe pain (Western Ontario and McMaster osteoarthritis index (WOMAC) score ≥301; 0–500 scale). Patients were randomised to receive 400 mg CS plus 500 mg GH three times a day or 200 mg celecoxib every day for 6 months. The primary outcome was the mean decrease in WOMAC pain from baseline to 6 months. Secondary outcomes included WOMAC function and stiffness, visual analogue scale for pain, presence of joint swelling/effusion, rescue medication consumption, Outcome Measures in Rheumatology Clinical Trials and Osteoarthritis Research Society International (OMERACT-OARSI) criteria and EuroQoL-5D.

Results

The adjusted mean change (95% CI) in WOMAC pain was −185.7 (−200.3 to −171.1) (50.1% decrease) with CS+GH and −186.8 (−201.7 to −171.9) (50.2% decrease) with celecoxib, meeting the non-inferiority margin of −40: −1.11 (−22.0 to 19.8; p=0.92). All sensitivity analyses were consistent with that result. At 6 months, 79.7% of patients in the combination group and 79.2% in the celecoxib group fulfilled OMERACT-OARSI criteria. Both groups elicited a reduction >50% in the presence of joint swelling; a similar reduction was seen for effusion. No differences were observed for the other secondary outcomes. Adverse events were low and similarly distributed between groups.

Conclusions

CS+GH has comparable efficacy to celecoxib in reducing pain, stiffness, functional limitation and joint swelling/effusion after 6 months in patients with painful knee osteoarthritis, with a good safety profile.

Trial registration number:

NCT01425853.

Quantitative proteomic profiling of human articular cartilage degradation in osteoarthritis

Osteoarthritis (OA) is the most common rheumatic pathology and is characterized primarily by articular cartilage degradation. Despite its high prevalence, there is no effective therapy to slow disease progression or regenerate the damaged tissue. Therefore, new diagnostic and monitoring tests for OA are urgently needed, which would also promote the development of alternative therapeutic strategies. In the present study, we have performed an iTRAQ-based quantitative proteomic analysis of secretomes from healthy human articular cartilage explants, comparing their protein profile to those from unwounded (early disease) and wounded (advanced disease) zones of osteoarthritic tissue. This strategy allowed us to identify a panel of 76 proteins that are distinctively released by the diseased tissue. Clustering analysis allowed the classification of proteins according to their different profile of release from cartilage. Among these proteins, the altered release of osteoprotegerin (decreased in OA) and periostin (increased in OA), both involved in bone remodelling processes, was verified in further analyses. Moreover, periostin was also increased in the synovial fluid of OA patients. Altogether, the present work provides a novel insight into the mechanisms of human cartilage degradation and a number of new cartilage-characteristic proteins with possible biomarker value for early diagnosis and prognosis of OA.

Which CAM modalities are worth considering?

This review-with a handy at-a-glance guide-examines 8 modalities, the level of evidence behind them, and the adverse effects you'll need to keep in mind.

A pharmacoproteomic study confirms the synergistic effect of chondroitin sulfate and glucosamine

Osteoarthritis (OA) is the most common age-related rheumatic disease. Chondrocytes play a primary role in mediating cartilage destruction and extracellular matrix (ECM) breakdown, which are main features of the OA joint. Quantitative proteomics technologies are demonstrating a very interesting power for studying the molecular effects of some drugs currently used to treat OA patients, such as chondroitin sulfate (CS) and glucosamine (GlcN). In this work, we employed the iTRAQ (isobaric tags for relative and absolute quantitation) technique to assess the effect of CS and GlcN, both alone and in combination, in modifying cartilage ECM metabolism by the analysis of OA chondrocytes secretome. 186 different proteins secreted by the treated OA chondrocytes were identified. 36 of them presented statistically significant differences (p ≤ 0.05) between untreated and treated samples: 32 were increased and 4 decreased. The synergistic chondroprotective effect of CS and GlcN, firstly reported by our group at the intracellular level, is now demonstrated also at the extracellular level.

Glucosamine for osteoarthritis: biological effects, clinical efficacy, and safety on glucose metabolism

Osteoarthritis is a chronic degenerative disorder that currently represents one of the main causes of disability within the elderly population and an important presenting complaint overall. The pathophysiologic basis of osteoarthritis entails a complex group of interactions among biochemical and mechanical factors that have been better characterized in light of a recent spike in research on the subject. This has led to an ongoing search for ideal therapeutic management schemes for these patients, where glucosamine is one of the most frequently used alternatives worldwide due to their chondroprotective properties and their long-term effects. Its use in the treatment of osteoarthritis is well established; yet despite being considered effective by many research groups, controversy surrounds their true effectiveness. This situation stems from several methodological aspects which hinder appropriate data analysis and comparison in this context, particularly regarding objectives and target variables. Similar difficulties surround the assessment of the potential ability of glucosamine formulations to alter glucose metabolism. Nevertheless, evidence supporting diabetogenesis by glucosamine remains scarce in humans, and to date, this association should be considered only a theoretical possibility.

Proteomic analysis of osteoarthritic chondrocyte reveals the hyaluronic acid-regulated proteins involved in chondroprotective effect under oxidative stress

Osteoarthritis (OA), the most common type of arthritis, is a degenerative joint disease. Oxidative stress is well known to play important roles in cartilage degradation and pathogenesis of OA. The intra-articular injection of hyaluronic acid (IAHA) is accepted as an effective clinical therapy for OA, but we do not yet fully understand the mechanisms underlying the effects of HA on OA chondrocytes under oxidative stress. Here, we show for the first time that IAHA significantly reduces the synovial fluid levels of hydrogen peroxide (H2O2) and superoxide (O2(-)) in patients with knee OA. We also demonstrate that HA suppresses H2O2-induced cell death in human OA chondrocytes. Proteomic approaches (2-DE combined with mass spectrometry) allowed us to identify 13 protein spots corresponding to 12 non-redundant proteins as HA-regulated proteins in OA chondrocytes under oxidative stress. The expression levels of three putative HA-regulated proteins (TALDO, ANXA1 and EF2) in control, H2O2-, HA- and HA/H2O2-treated OA chondrocytes were verified by Western blotting and the results indeed support the notion that HA acts in anti-oxidation, anti-apoptosis, and the promotion of cell survival. Our results collectively demonstrate the utility of proteomic approaches and provide new insights into the chondroprotective effects of HA on OA.

BIOLOGICAL SIGNIFICANCE

In the present study, we show for the first time that IAHA reduces the levels of H2O2 and O2(-) in synovial fluids from OA patients. We used primary cultured human OA chondrocytes as a model, treated cells with H2O2 to partly mimic their physiological conditions under oxidative stress, and examined the protection effects of HA. The proteomic approach allowed us to identify candidate proteins regulated by H2O2 and/or HA in OA chondrocytes. We found that proteins functioning in stress responses, apoptosis and protein synthesis were consistently regulated by HA in chondrocytes under oxidative stress. These novel results contribute to our understanding of the molecular mechanisms underlying HA-mediated chondroprotection.

Specialty supplement use and biologic measures of oxidative stress and DNA damage

BACKGROUND

Oxidative stress and resulting cellular damage have been suggested to play a role in the etiology of several chronic diseases, including cancer and cardiovascular disease. Identifying factors associated with reduced oxidative stress and resulting damage may guide future disease-prevention strategies.

METHODS

In the VITamins And Lifestyle (VITAL) biomarker study of 209 persons living in the Seattle area, we examined the association between current use of several specialty supplements and oxidative stress, DNA damage, and DNA repair capacity. Use of glucosamine, chondroitin, fish oil, methylsulfonylmethane (MSM), coenzyme Q10 (CoQ10), ginseng, ginkgo, and saw palmetto was ascertained by a supplement inventory/interview, whereas the use of fiber supplements was ascertained by questionnaire. Supplements used by more than 30 persons (glucosamine and chondroitin) were evaluated as the trend across number of pills/week (non-use, <14 pills/week, 14+ pills/week), whereas less commonly used supplements were evaluated as use/non-use. Oxidative stress was measured by urinary 8-isoprostane and PGF2α concentrations using enzyme immunoassays (EIA), whereas lymphocyte DNA damage and DNA repair capacity were measured using the Comet assay. Multivariate-adjusted linear regression was used to model the associations between supplement use and oxidative stress/DNA damage.

RESULTS

Use of glucosamine (Ptrend: 0.01), chondroitin (Ptrend: 0.003), and fiber supplements (P: 0.01) was associated with reduced PGF2α concentrations, whereas CoQ10 supplementation was associated with reduced baseline DNA damage (P: 0.003).

CONCLUSIONS

Use of certain specialty supplements may be associated with reduced oxidative stress and DNA damage.

IMPACT

Further research is needed to evaluate the association between specialty supplement use and markers of oxidative stress and DNA damage.

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.

Secretome analysis of chondroitin sulfate-treated chondrocytes reveals anti-angiogenic, anti-inflammatory and anti-catabolic properties

INTRODUCTION

Chondroitin sulfate (CS) is a symptomatic slow-acting drug for osteoarthritis (OA) widely used in the clinic. The aim of this work is to find proteins whose secretion from cartilage cells under proinflammatory stimuli (IL-1β) is regulated by CS, employing a novel quantitative proteomic approach.

METHODS

Human articular chondrocytes released from three normal cartilages were grown in SILAC medium. When complete incorporation of the heavy isotope was achieved, chondrocytes were stimulated with IL-1β 5 ng/ml with or without CS pretreatment (200 µg/ml). Forty-eight hours later, chondrocyte secretomes were analyzed by nano-scale liquid chromatography-mass spectrometry. Real-time PCR, western blot and immunohistochemistry analyses were employed to confirm some of the results.

RESULTS

We could identify 75 different proteins in the secretome of human articular chondrocytes. Eighteen of these were modulated by CS with statistical significance (six increased and 12 decreased). In normal chondrocytes stimulated with IL-1β, CS reduces inflammation directly by decreasing the presence of several complement components (CFAB, C1S, CO3, and C1R) and also indirectly by increasing proteins such as TNFα-induced protein (TSG6). TSG6 overexpression correlates with a decrease in pro-matrix metalloproteinase activation (observed in MMP1 and MMP3 levels). Finally, we observed a strong CS-dependent increase of an angiogenesis inhibitor, thrombospondin-1.

CONCLUSION

We have generated a quantitative profile of chondrocyte extracellular protein changes driven by CS in the presence of IL-1β. We have also provided novel evidences of its anti-angiogenic, anti-inflammatory, and anti-catabolic properties. Demonstration of the anti-angiogenic action of CS might provide a novel therapeutic approach for OA targeting.

Nutritional care for aging cats and dogs

Veterinarians need to be prepared to provide nutritional advice for healthy pets as well as for pets that are ill. Before instituting a dietary change in any patient, especially an older dog or cat, a nutritional evaluation should be completed. This should include an evaluation of the patient, the current diet, and feeding management. Diets should be appropriate to the unique needs of the individual patient. Many diseases in senior pets are “diet-sensitive” meaning that diet can play a role in managing the effects of the disease. Common examples discussed include cognitive dysfunction of aging, osteoarthritis, and obesity.

Proteome analysis during chondrocyte differentiation in a new chondrogenesis model using human umbilical cord stroma mesenchymal stem cells

Umbilical cord stroma mesenchymal stem cells were differentiated toward chondrocyte-like cells using a new in vitro model that consists of the random formation of spheroids in a medium supplemented with fetal bovine serum on a nonadherent surface. The medium was changed after 2 days to one specific for the induction of chondrocyte differentiation. We assessed this model using reverse transcriptase-polymerase chain reaction, flow cytometry, immunohistochemistry, and secretome analyses. The purpose of this study was to determine which proteins were differentially expressed during chondrogenesis. Differential gel electrophoresis analysis was performed, followed by matrix-assisted laser desorption/ionization mass spectrometry protein identification. A total of 97 spots were modulated during the chondrogenesis process, 54 of these spots were identified as 39 different proteins and 15 were isoforms. Of the 39 different proteins identified 15 were down-regulated, 21 were up-regulated, and 3 were up- and down-regulated during the chondrogenesis process. Using Pathway Studio 7.0 software, our results showed that the major cell functions modulated during chondrogenesis were cellular differentiation, proliferation, and migration. Five proteins involved in cartilage extracellular matrix metabolism found during the differential gel electrophoresis study were confirmed using Western blot. The results indicate that our in vitro chondrogenesis model is an efficient and rapid technique for obtaining cells similar to chondrocytes that express proteins characteristic of the cartilage extracellular matrix. These chondrocyte-like cells could prove useful for future cell therapy treatment of cartilage pathologies.

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.

Pharmacoproteomic study of three different chondroitin sulfate compounds on intracellular and extracellular human chondrocyte proteomes

Chondroitin sulfate (CS) is a symptomatic slow acting drug for osteoarthritis (OA) widely used for the treatment of this highly prevalent disease, characterized by articular cartilage degradation. However, little is known about its mechanism of action, and recent large scale clinical trials have reported variable results on OA symptoms. Herein, we aimed to study the modulations in the intracellular proteome and the secretome of human articular cartilage cells (chondrocytes) treated with three different CS compounds, with different origin or purity, by two complementary proteomic approaches. Osteoarthritic cells were treated with 200 μg/ml of each brand of CS. Quantitative proteomics experiments were carried out by the DIGE and stable isotope labeling with amino acids in cell culture (SILAC) techniques, followed by LC-MALDI-MS/MS analysis. The DIGE study, carried out on chondrocyte whole cell extracts, led to the detection of 46 spots that were differential between conditions in our study: 27 were modulated by CS1, 4 were modulated by CS2, and 15 were modulated by CS3. The SILAC experiment, carried out on the subset of chondrocyte-secreted proteins, allowed us to identify 104 different proteins. Most of them were extracellular matrix components, and 21 were modulated by CS1, 13 were modulated by CS2, and 9 were modulated by CS3. Each of the studied compounds induces a characteristic protein profile in OA chondrocytes. CS1 displayed the widest effect but increased the mitochondrial superoxide dismutase, the cartilage oligomeric matrix protein, and some catabolic or inflammatory factors like interstitial collagenase, stromelysin-1, and pentraxin-related protein. CS2 and CS3, on the other hand, increased a number of structural proteins, growth factors, and extracellular matrix proteins. Our study shows how, from the three CS compounds tested, CS1 induces the activation of inflammatory and catabolic pathways, whereas CS2 and CS3 induce an anti-inflammatory and anabolic response. The data presented emphasize the importance of employing high quality CS compounds, supported by controlled clinical trials, in the therapy of OA. Finally, the present work exemplifies the usefulness of proteomic approaches in pharmacological studies.

Proteomic analysis on acetate metabolism in Citrobacter sp. BL-4

Mass production of glucosamine (GlcN) using microbial cells is a worthy approach to increase added values and keep safety problems in GlcN production process. Prior to set up a microbial cellular platform, this study was to assess acetate metabolism in Citrobacter sp. BL-4 (BL-4) which has produced a polyglucosamine PGB-2. The LC-MS analysis was conducted after protein separation on the 1D-PAGE to accomplish the purpose of this study. 280 proteins were totally identified and 188 proteins were separated as acetate-related proteins in BL-4. Acetate was converted to acetyl-CoA by acetyl-CoA synthetase up-regulated in the acetate medium. The glyoxylate bypass in the acetate medium was up-regulated with over-expression of isocitrate lyases and 2D-PAGE confirmed this differential expression. Using ¹H-NMR analysis, the product of isocitrate lyases, succinate, increased about 15 times in the acetate medium. During acetate metabolism proteins involved in the lipid metabolism and hexosamine biosynthesis were over-expressed in the acetate medium, while proteins involved in TCA cycle, pentose phosphate cycle and purine metabolism were down-regulated. Taken together, the results from the proteomic analysis can be applied to improve GlcN production and to develop metabolic engineering in BL-4.

Metabolic labeling of chondrocytes for the quantitative analysis of the interleukin-1-beta-mediated modulation of their intracellular and extracellular proteomes

Chondrocytes are widely used as an in vitro model of cartilage diseases such as osteoarthritis (OA). As the unique residents of mature cartilage, they are responsible of the synthesis and release of proteins essential for a proper tissue turnover. In this work, the stable isotope labeling with amino acids in cell culture (SILAC) technique has been standardized in primary human articular chondrocytes (HACs) for quantitative proteomic analyses. Then, it has been employed to study those protein modifications caused by the proinflammatory cytokine Interleukin-1beta (IL-1β), a well-known OA mediator, in these cells. Quantitative analysis of the IL-1β-treated HACs proteome revealed a global increase in cellular chaperones concurrent with a down-regulation of the actin cytoskeleton. HACs secretome analysis led to the identification and quantification of 115 proteins and unveiled the effects of the cytokine on the cartilage extracellular matrix metabolism. Among those modulated proteins, three protein clusters were found to be remarkably increased by IL-1β: proinflammatory mediators and proteases, type VI collagen and proteins known to bind this molecule, and proteins related with the TGF-beta pathway. On the other hand, secretion of aggrecan, two vitamin K-dependent proteins, and thrombospondin, among others, was strongly reduced. Altogether, these data demonstrate the usefulness of metabolic labeling for quantitative proteomics studies in HACs, show the complementarity of intracellular proteome and secretome analyses, and provide a comprehensive study of the IL-1β-mediated effects on these cells. Proteins identified in the secretome approach have a potential use as biomarkers or therapeutic targets for OA.

A novel procedure for protein extraction from formalin-fixed paraffin-embedded tissues

Most of the archived pathological specimens in hospitals are kept as formalin-fixed paraffin-embedded tissues (FFPE) for long-term preservation. Up to now, these samples are only used for immunohistochemistry in a clinical routine as it is difficult to recover intact protein from these FFPE tissues. Here, we report a novel, short time-consuming and cost-effective method to extract full-length, non-degraded proteins from FFPE tissues. This procedure is combined with an effective and non-toxic deparaffinisation process and an extraction method based on antigen-retrieval, high concentration of SDS and high temperature. We have obtained enough intact protein to be detected by Western blotting analysis. This technique will allow utilising these stored FFPE tissues in several applications for protein analysis helping to advance the translational studies in cancer and other diseases.