Combined Treatment With Chondroitin Sulfate and Glucosamine Sulfate Shows No Superiority Over Placebo for Reduction of Joint Pain and Functional Impairment in Patients With Knee Osteoarthritis: A Six‐Month Multicenter, Randomized, Double‐Blind, Placebo‐Controlled Clinical Trial

In vitro and in vivo studies of the therapeutic potential of Tinospora crispa extracts in osteoarthritis: Targeting oxidation, inflammation, and chondroprotection

ETHNOPHARMACOLOGICAL RELEVANCE

The increasing incidence of osteoarthritis (OA), especially among the elderly population, highlights the need for more efficacious treatments that go beyond mere symptomatic relief. Tinospora crispa (L.) Hook. f. & Thomson (TC) boasts a rich traditional heritage, widespread use in Ayurveda, traditional Chinese medicine (TCM), and diverse indigenous healing practices throughout Southeast Asia for treating arthritis, rheumatism, fever, and inflammation.

AIM OF THE STUDY

This study investigates the anti-inflammatory and chondroprotective potential of TC stem extracts, including ethanolic TC extract (ETCE) and aqueous TC extract (ATCE), in modulating OA pathogenesis through in vitro and in vivo approaches.

MATERIALS AND METHODS

The study utilized LC-MS/MS to identify key compounds in TC stem extracts. In vitro experiments assessed the antioxidative and anti-inflammatory properties of ETCE and ATCE in activated macrophages, while an in vivo monoiodoacetate (MIA)-induced OA rat model evaluated the efficacy of ETCE treatment. Key markers of oxidative stress, such as superoxide dismutase (SOD) and catalase (CAT), were assessed alongside pro-inflammatory cytokines TNF-α and IL-1β, and matrix-degrading enzymes, matrix metalloproteinase (MMP 13 and MMP 3), to evaluate the therapeutic effects of TC stem extracts on OA.

RESULTS

Chemical profiling of the extracts was conducted using LC-MS/MS in positive ionization, identifying seven compounds, including pseudolaric acid B, stylopine, and reticuline, which were reported for the first time in this species. The study utilized varying concentrations of TC stem extracts, specifically 6.25-25 μg/mL for in vitro assays and 500 mg/kg for in vivo studies. Our findings also revealed that both ETCE and ATCE exhibit dose-dependent reduction in reactive oxygen species (41%-52%) and nitric oxide (NO) levels (50% and 72%), with ETCE displaying superior antioxidative efficacy and marked anti-inflammatory properties, significantly reducing TNF-α and IL-6 at concentrations above 12.5 μg/mL. In the MIA-induced OA rat model, ETCE treatment notably outperformed ATCE, markedly lowering TNF-α (1.91 ± 0.37 pg/mL) and IL-1β (26.30 ± 3.68 pg/mL) levels and effectively inhibiting MMP 13 and MMP 3 enzymes. Furthermore, macroscopic and histopathological assessments, including ICRS scoring and OARSI grading, indicate that TC stem extracts reduce articular damage and proteoglycan loss in rat knee cartilage. These results suggest that TC stem extracts may play a role in preventing cartilage degradation and potentially alleviating inflammation and pain associated with OA, though further studies are needed to confirm these effects.

CONCLUSION

This study highlights the potential of TC stem extracts as a novel, chondroprotective therapeutic avenue for OA management. By targeting oxidative stress, pro-inflammatory cytokines, and cartilage-degrading enzymes, TC stem extracts promise to prevent cartilage degradation and alleviate inflammation and pain associated with OA.

Inflammation as a therapeutic target for osteoarthritis: A literature review of clinical trials

The burden of osteoarthritis (OA) is rapidly increasing with population aging, but there are still no approved disease-modifying drugs available. Accumulating evidence has shown that OA is a heterogeneous disease with multiple phenotypes, and it is unlikely to respond to one-size-fits-all treatments. Inflammation is recognized as an important phenotype of OA and is associated with worse pain and joint deterioration. Therefore, it is believed that anti-inflammatory treatments may be more effective for OA with an inflammatory phenotype. In this review, we summarized clinical trials that evaluated anti-inflammatory treatments for OA and discussed whether these treatments are more effective in inflammatory OA phenotypes compared to general OA patients.

Sargassum polysaccharide attenuates osteoarthritis in rats and is associated with the up-regulation of the ITGβ1-PI3K-AKT signaling pathway

Background

Osteoarthritis (OA) presents a formidable challenge, characterized by as-yet-unclear mechanical intricacies within cartilage and the dysregulation of bone homeostasis. Our preliminary data revealed the encouraging potential of a Sargassum polysaccharide (SP), in promoting chondrogenesis. The aim of our study is to comprehensively assess the therapeutic effects of SP on OA models and further elucidate its potential mechanism.

Methods

The protective effects of SP were initially evaluated in an inflammation-induced human chondrocyte (C28) cell model. CCK-8 assays, Alcian blue staining, RT-qPCR and Western blotting were used to verify the chondrogenesis of SP in vitro. To assess the efficacy of SP in vivo, surgically induced medial meniscus destabilization (DMM) OA rats underwent an 8-week SP treatment. The therapeutic effects of SP in OA rats were comprehensively evaluated using X-ray imaging, micro-computed tomography (μ-CT), histopathological analysis, as well as immunohistochemical and immunofluorescent staining. Following these assessments, we delved into the potential signaling pathways of SP in inflammatory chondrocytes utilizing RNA-seq analysis. Validation of these findings was conducted through RT-qPCR and western blotting techniques.

Results

SP significantly enhance the viability of C28 chondrocytes, and increased the secretion of acidic glycoproteins. Moreover, SP stimulated the expression of chondrogenic genes (Aggrecan, Sox9, Col2a1) and facilitated the synthesis of Collagen II protein in C28 inflammatory chondrocytes. In vivo experiments revealed that SP markedly ameliorated knee joint stenosis, alleviated bone and cartilage injuries, and reduced the histopathological scores in the OA rats. μ-CT analysis confirmed that SP lessened bone impairments in the medial femoral condyle and the subchondral bone of the tibial plateau, significantly improving the microarchitectural parameters of the subchondral bone. Histopathological analyses indicated that SP notably enhanced cartilage quality on the surface of the tibial plateau, leading to increased cartilage thickness and area. Immunohistochemistry staining and immunofluorescence staining corroborated these findings by showing a significant promotion of Collagen II expression in OA joints treated with SP. RNA-seq analysis suggest that SP's effects were mediated through the regulation of the ITGβ1-PI3K-AKT signaling axis, thereby stimulating chondrogenesis. Verification through RT-qPCR and Western blot analyses confirmed that SP significantly upregulated the expression of ITGβ1, p110δ, AKT1, ACAN, and Col2a1. Notably, knock-down of ITGβ1 using siRNA in C28 chondrocytes inhibited the expression of ITGβ1, p110δ, AKT1, and ACAN. However, these inhibitory effects were not completely reversed by supplemental SP intervention.

Conclusions

In summary, our findings reveal that SP significantly enhances chondrogenesis both in vitro and in vivo, alleviating OA progression both in bone and cartilage. The observed beneficial effects are intricately linked to the activation of the ITGβ1-PI3K-AKT signaling axis.

The translational potential of this article

Our research marks the first instance unveiling the advantageous effects and underlying mechanisms of SP in OA treatment. With its clinical prospects, SP presents compelling new evidence for the advancement of a next-generation polysaccharide drug for OA therapy.

Evaluation of efficacy and safety of glucosamine sulfate, chondroitin sulfate, and their combination regimen in the management of knee osteoarthritis: a systematic review and meta-analysis

AIM

This study was aimed to assess the efficacy and safety of two oral Symptomatic Slow Acting Drugs for Osteoarthritis (SYSADOAs)-Glucosamine Sulfate, Chondroitin Sulfate, and their combination regimen in the management of knee osteoarthritis (KOA).

METHODS

This systematic review was conducted according to PRISMA 2020 guidelines. A detailed literature search was performed from 03/1994 to 31/12/2022 using various electronic databases including PubMed, Embase, Cochrane Library, and Google Scholar, using the search terms-Glucosamine sulfate (GS), Chondroitin sulfate (CS), Knee osteoarthritis, Joint pain, Joint disease, and Joint structure, for literature concerning glucosamine, chondroitin, and their combination in knee osteoarthritis treatment. Cochrane Collaboration's Risk assessment tool (version 5.4.1) was used for assessing the risk of bias and the quality of the literature. The data was extracted from the included studies and subjected to statistical analysis to determine the beneficial effect of Glucosamine Sulfate, Chondroitin Sulfate, and their combination.

RESULTS

Twenty-five randomized controlled trials (RCTs) were included in this systematic review. In short, exclusively 9 RCTs for GS, 13 RCTs for CS, and 3 RCTs for the combination of GS and CS. All these studies had their treatment groups compared with placebo. In the meta-analysis, CS showed a significant reduction in pain intensity, and improved physical function compared to the placebo; GS showed a significant reduction in tibiofemoral joint space narrowing. While the combination of GS and CS showed neither a reduction in pain intensity, nor any improvement in the physical function. However, the combination exhibited a non-significant reduction in joint space narrowing. In the safety evaluation, both CS and GS have shown good safety profile and were well tolerated.

CONCLUSION

This meta-analysis revealed that the CS (with decreased pain intensity and improvement in the physical function), and GS (with significant reduction in the joint space narrowing) have significant therapeutic benefits. However, their combination did not significantly improve the symptoms or modify the disease. This may be due to the limited trials that are available on the combination of the sulfate forms of the intervention. Hence, there is a scope for conducting multicentric randomised controlled trials to evaluate and conclude the therapeutic role of CS and GS combination in the management of KOA.

The effect of combined hydrolyzed type 2 collagen, methylsulfonylmethane, glucosamine sulfate and chondroitin sulfate supplementation on knee osteoarthritis symptoms

Objectives

This study aimed to evaluate the effects of the combined hydrolyzed type 2 collagen, methylsulfonylmethane (MSM), glucosamine sulfate (GS), and chondroitin sulfate (CS) supplement on knee pain intensity in patients with knee osteoarthritis (OA).

Patients and methods

This multicenter, observational, noninterventional study included 98 patients (78 females, 20 males; mean age: 52.8±6.5 years; range, 40 to 64 years) who had Grade 1-3 knee OA between May 2022 and November 2022. The patients were prescribed the combination of hydrolyzed type 2 collagen, MSM, GS, and CS as a supplement for knee OA. The sachet form of the combined supplement containing 1250 mg hydrolyzed type 2 collagen, 750 mg MSM, 750 mg GS, and 400 mg CS was used once daily for two consecutive months. Patients were evaluated according to the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Visual Analog Scale (VAS)-pain, and Health Assessment Questionnaire (HAQ). Patients were scheduled to visit for follow-up four weeks (Visit 2) and eight weeks (Visit 3) after Visit 1 (baseline; day 0 of the study).

Results

For the VAS-pain, WOMAC, WOMAC-subscale, and HAQ scores, the differences in improvement between the three visits were significant (p<0.001 for all). The patient compliance with the supplement was a median of 96.77%, both for Visit 2 and Visit 3.

Conclusion

The combination of hydrolyzed type 2 collagen, MSM, GS, and CS for eight weeks in knee OA was considered an effective and safe nutritional supplement.

Future proofing of chondroitin sulphate production: Importance of sustainability and quality for the end-applications

Chondroitin sulphates (CSs) are the most well-known glycosaminoglycans (GAGs) found in any living organism, from microorganisms to invertebrates and vertebrates (including humans), and provide several health benefits. The applications of CSs are numerous including tissue engineering, osteoarthritis treatment, antiviral, cosmetics, and skincare applications. The current commercial production of CSs mostly uses animal, bovine, porcine, and avian tissues as well as marine organisms, marine mammals, sharks, and other fish. The production process consists of tissue hydrolysis, protein removal, and purification using various methods. Mostly, these are chemical-dependent and are complex, multi-step processes. There is a developing trend for abandonment of harsh extraction chemicals and their substitution with different green-extraction technologies, however, these are still in their infancy. The quality of CSs is the first and foremost requirement for end-applications and is dependent on the extraction and purification methodologies used. The final products will show different bio-functional properties, depending on their origin and production methodology. This is a comprehensive review of the characteristics, properties, uses, sources, and extraction methods of CSs. This review emphasises the need for extraction and purification processes to be environmentally friendly and gentle, followed by product analysis and quality control to ensure the expected bioactivity of CSs.

Recent progress in marine chondroitin sulfate, dermatan sulfate, and chondroitin sulfate/dermatan sulfate hybrid chains as potential functional foods and therapeutic agents

Chondroitin sulfate (CS), dermatan sulfate (DS), and CS/DS hybrid chains are natural complex glycosaminoglycans with high structural diversity and widely distributed in marine organisms, such as fish, shrimp, starfish, and sea cucumber. Numerous CS, DS, and CS/DS hybrid chains with various structures and activities have been obtained from marine animals and have received extensive attention. However, only a few of these hybrid chains have been well-characterized and commercially developed. This review presents information on the extraction, purification, structural characterization, biological activities, potential action mechanisms, and structure-activity relationships of marine CS, DS, and CS/DS hybrid chains. We also discuss the challenges and perspectives in the research of CS, DS, and CS/DS hybrid chains. This review may provide a useful reference for the further investigation, development, and application of CS, DS, and CS/DS hybrid chains in the fields of functional foods and therapeutic agents.

Analysis of the gut microbiome in sled dogs reveals glucosamine- and activity-related effects on gut microbial composition

The composition of the microbiome influences many aspects of physiology and health, and can be altered by environmental factors, including diet and activity. Glucosamine is a dietary supplement often administered to address arthritic symptoms in humans, dogs, and other mammals. To investigate how gut microbial composition varies with glucosamine supplementation, we performed 16S rRNA sequence analysis of fecal samples from 24 Alaskan and Inuit huskies and used mixed effects models to investigate associations with activity, age, and additional factors. Glucosamine ingestion, age, activity, sex, and diet were correlated with differences in alpha-diversity, with diversity decreasing in dogs consuming glucosamine. Beta-diversity analysis revealed clustering of dogs based on glucosamine supplementation status. Glucosamine supplementation and exercise-related activity were associated with greater inter-individual pairwise distances. At the family level, Lactobacillaceae and Anaerovoracaceae relative abundances were lower in supplemented dogs when activity was accounted for. At the genus level, Eubacterium [brachy], Sellimonus, Parvibacter, and an unclassified genus belonging to the same family as Parvibacter (Eggerthellaceae) all were lower in supplemented dogs, but only significantly so post-activity. Our findings suggest that glucosamine supplementation alters microbiome composition in sled dogs, particularly in the context of exercise-related activity.

Effects of adding glucosamine or glucosamine combined with chondroitin to exercise on pain and physical function in adults with knee osteoarthritis: a systematic review and meta-analysis

It is well known that different types of exercise significantly improve physical function and relieve pain in knee osteoarthritis (KOA) patients. The aim of this study was to investigate the added effects of glucosamine or glucosamine and chondroitin supplementation in combination with an exercise program in the management of KOA. The randomized controlled trials on adding glucosamine (G) or G combined with chondroitin (C) to an exercise program in the treatment of KOA were searched in the PubMed, Cochrane Central Register of Controlled Trials, PEDro, and Web of Science online databases. The Pedro scale tool was used to assess quality of literature. A meta-analysis was performed using the Review Manager 5.4 software. In total, 6 studies (including 297 participants) were included for the final meta-analysis. According to the PEDro scale, the average quality of the studies was rated as good (mean = 8.2 (2)). The results showed that the effect of G, or G and C, in combination with exercise is not significant, as indicated by the assessed knee pain (WOMAC pain: SMD -0.18, 95% CI -0.47 to 0.11, p = 0.23; and VAS pain: SMD -0.34, 95% CI -0.85 to 0.17, p = 0.20) and physical function (SMD -0.13, 95% CI -0.95 to 0.69, p = 0.76). Adding glucosamine alone or a combination of glucosamine and chondroitin to exercise, has no effect on knee pain and physical function compared with exercise alone in KOA patients. Keywords: treatment, dietary supplement, physical activity, older adults.

Sulfoconjugation of protein peptides and glycoproteins in physiology and diseases

Protein sulfoconjugation, or sulfation, represents a critical post-translational modification (PTM) process that involves the attachment of sulfate groups to various positions of substrates within the protein peptides or glycoproteins. This process plays a dynamic and complex role in many physiological and pathological processes. Here, we summarize the importance of sulfation in the fields of oncology, virology, drug-induced liver injury (DILI), inflammatory bowel disease (IBD), and atherosclerosis. In oncology, sulfation is involved in tumor initiation, progression, and migration. In virology, sulfation influences viral entry, replication, and host immune response. In DILI, sulfation is associated with the incidence of DILI, where altered sulfation affects drug metabolism and toxicity. In IBD, dysregulation of sulfation compromises mucosal barrier and immune response. In atherosclerosis, sulfation influences the development of atherosclerosis by modulating the accumulation of lipoprotein, and the inflammation, proliferation, and migration of smooth muscle cells. The current review underscores the importance of further research to unravel the underlying mechanisms and therapeutic potential of targeting sulfoconjugation in various diseases. A better understanding of sulfation could facilitate the emergence of innovative diagnostic or therapeutic strategies.

Habitual glucosamine use, APOE genotypes, and risk of incident cause-specific dementia in the older population

BACKGROUND

The relationship of glucosamine use with incident dementia in the older population remains uncertain. We aimed to evaluate the longitudinal association between habitual glucosamine supplement and the risk of cause-specific dementia and examine the possible effect modifiers on this association.

METHODS

The study included 214,945 participants over the age of 60 who had available information on glucosamine use and did not have dementia at baseline in the UK Biobank. The APOE genotypes were determined by a combination variant of rs429358 and rs7412. The primary outcome was incident vascular dementia, incident Alzheimer's disease, and incident frontotemporal dementia, respectively.

RESULTS

Over a median follow-up duration of 12 years, 1039, 1774, and 122 participants developed vascular dementia, Alzheimer's disease, and frontotemporal dementia, respectively. Overall, habitual glucosamine use was significantly associated with a lower risk of incident vascular dementia (adjusted HR, 0.82; 95%CI, 0.70-0.96), but not significantly associated with incident Alzheimer's disease (adjusted HR, 1.02; 95%CI, 0.92-1.14) and incident frontotemporal dementia (adjusted HR, 0.95; 95%CI, 0.63-1.43). Moreover, the inverse association between habitual glucosamine use and incident vascular dementia was more pronounced in participants with concomitant supplement of calcium (P-interaction = 0.011), and those without concomitant supplement of zinc (P-interaction = 0.018). However, APOE ε4 dosage and baseline cognitive function did not significantly modify the relationships of glucosamine use with incident vascular dementia or Alzheimer's disease (All P-interactions > 0.05).

CONCLUSIONS

Regardless of APOE genotypes and baseline cognitive function, habitual glucosamine use was significantly inversely associated with incident vascular dementia in the older population.

Concurrent Imaging and Clinical Study of the Efficacy of Hyaluronic Acid Injection for Knee Osteoarthritis: A Synovial Membrane Investigation with Ultrasound Imaging

We investigated whether hyaluronic acid (HA) injections can ameliorate ultrasound-detected synovitis in knee osteoarthritis (OA). We recruited 103 patients with symptomatic knee OA and ultrasound-detected synovitis and performed two ultrasound-guided fluid drainage procedures, followed by the administration of a low-molecular-weight HA injection (2.5 mL) in the subpatellar bursa, at a 2-week interval. Knee ultrasound imaging evaluations were performed before injection (baseline) and at 1 and 6 months after the second injection and included the measurements of synovial vascularity by using color Doppler ultrasound, synovial fluid depth over the suprapatellar bursa (SF), and synovial hypertrophy (SH). Initial clinical assessments included a visual analog scale (VAS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). VAS scores decreased significantly at both 1-month and 6-month evaluations (p < 0.001). WOMAC scores also significantly decreased at 1 month (p < 0.001), but not at 6 months (p = 0.23). The ultrasound parameters did not significantly change, except color Doppler grading, which tended to decrease at the 6-month evaluation (p = 0.059). Our findings revealed that two ultrasound-guided HA injections following fluid drainage improved pain and knee function but did not considerably influence imaging-detected synovitis in patients with knee OA.

Chondroitin sulfate and glucosamine combination in patients with knee and hip osteoarthritis: A long-term observational study in Russia

BACKGROUND

Oral treatment of glucosamine (GA) combined with chondroitin sulfate (CS) was reportedly effective for pain relief and function improvement in osteoarthritis patients with moderate to severe knee pain in clinical trials. While the effectiveness of GA and CS on both clinical and radiological findings has been demonstrated, only a few high-quality trials exist. Therefore, controversy regarding their effectiveness in real-world clinical practice remains.

AIM

To investigate the impact of GA + CS on clinical outcomes of patients with knee and hip osteoarthritis in routine clinical practice.

METHODS

A multicenter prospective observational cohort study included 1102 patients of both genders with knee or hip osteoarthritis (Kellgren & Lawrence grades I-III) in 51 clinical centers in the Russian Federation from November 20, 2017, to March 20, 2020, who had started to receive oral capsules of glucosamine hydrochloride 500 mg and CS 400 mg according to the approved patient information leaflet starting from 3 capsules daily for 3 wk, followed by a reduced dosage of 2 capsules daily before study inclusion (minimal recommended treatment duration is 3-6 mo). Changes in subscale scores [Pain, Symptoms, Function, and Quality of Life (QOL)] of the Knee Injury and Osteoarthritis Outcome Score (KOOS)/Hip Disability and Osteoarthritis Outcome Score (HOOS) questionnaires during the observational period (up to 54-64 wk with a total of 4 visits). Patients’ treatment satisfaction, data on the combined oral use of glucosamine hydrochloride and CS, concomitant use of non-steroidal anti-inflammatory drugs (NSAIDs), and adverse events (AEs) were also evaluated.

RESULTS

A total of 1102 patients with knee and hip osteoarthritis were included in the study. The mean patient age was 60.4 years, most patients were women (87.8%), and their average body mass index was 29.49 kg/m². All subscale scores (Pain, Symptoms, Function, and QOL) of the KOOS and HOOS demonstrated clinically and statistically significant improvements. In patients with knee osteoarthritis, the mean score increases from baseline to the end of Week 64 were 22.87, 20.78, 16.60, and 24.87 on Pain, Symptoms, Physical Function (KOOS-PS), and QOL subscales (P < 0.001 for all), respectively. In patients with hip osteoarthritis, the mean score increases were 22.81, 19.93, 18.77, and 22.71 on Pain, Symptoms, Physical Function (HOOS-PS), and QOL subscales (P < 0.001 for all), respectively. The number of patients using any NSAIDs decreased from 43.1% to 13.5% (P < 0.001) at the end of the observation period. Treatment-related AEs occurred in 2.8% of the patients and mainly included gastrointestinal disorders [25 AEs in 24 (2.2%) patients]. Most patients (78.1%) were satisfied with the treatment.

CONCLUSION

Long-term oral GA + CS was associated with decreased pain, reduced concomitant NSAID therapy, improved joint function and QOL in patients with knee and hip osteoarthritis in routine clinical practice.

Efficacy and safety of the combination of glucosamine and chondroitin for knee osteoarthritis: a systematic review and meta-analysis

AIMS

Though glucosamine and chondroitin have become common practices for treating knee osteoarthritis, the clinical value of these two drugs in combination are still questionable. To evaluate the efficacy and safety of the combination of glucosamine (GS) and chondroitin (CS) in knee osteoarthritis (KOA) treatment.

METHODS

We searched electronic databases, including PubMed, Embase, Web of Science, SCOPUS, The Cochrane Central Register of Controlled Trials (CENTRAL), OVID, Chinese Clinical Trial Registry (ChiCTR), CBM, CNKI, WanFang and VIP from their inception to August 20, 2020, for literature concerning the combination of glucosamine and chondroitin in knee osteoarthritis treatment. The Cochrane Collaboration's tool for assessing risk of bias and Jadad scale were used to evaluate the risk of bias and quality of literature. The meta-analysis was performed using Review Manager 5.3 software.

RESULTS

Eight randomized controlled trials (RCTs) were included, including 7 studies in English and 1 study in Chinese. While the number of included papers was quite limited, the number of participants was decent, and quality appraisal result is acceptable. The total number of patients was 3793, with 1067 patients receiving a combination of glucosamine and chondroitin and 2726 patients receiving other treatments. The meta-analysis results revealed the following: (1) Regarding the total Western Ontario and McMaster Universities Arthritis Index (WOMAC) score, compared with the placebo group, the combination group showed a statistically significant advantage [MD = - 12.04 (- 22.33 ~ - 1.75); P = 0.02], while the other groups showed no significance. (2) Regarding the VAS score, none of the comparisons showed significance. (3) In the secondary outcomes, except the comparison of JSN between the combination and placebo groups (MD = - 0.09 (- 0.18 ~ - 0.00); P = 0.04) and the comparison of the WOMAC stiffness score between the combination and CS groups [MD = - 4.70 (- 8.57 ~ - 0.83); P = 0.02], none of the comparisons showed a significant difference. (4)Safety analysis results show that none of the comparisons have significant differences.

CONCLUSION

Our study confirmed that the combination of glucosamine and chondroitin is effective and superior to other treatments in knee osteoarthritis to a certain extent. It is worthwhile to popularize and apply the combination in KOA treatment considering the point of effect, tolerability and economic costs. Additionally, regarding the limited number of studies and uneven trial quality, more high-quality trials are required to investigate the accurate clinical advantages of the combination.

PROSPERO REGISTRATION ID

CRD42020202093.

Strategic application of imaging in DMOAD clinical trials: focus on eligibility, drug delivery, and semiquantitative assessment of structural progression

Despite decades of research efforts and multiple clinical trials aimed at discovering efficacious disease-modifying osteoarthritis (OA) drugs (DMOAD), we still do not have a drug that shows convincing scientific evidence to be approved as an effective DMOAD. It has been suggested these DMOAD clinical trials were in part unsuccessful since eligibility criteria and imaging-based outcome evaluation were solely based on conventional radiography. The OA research community has been aware of the limitations of conventional radiography being used as a primary imaging modality for eligibility and efficacy assessment in DMOAD trials. An imaging modality for DMOAD trials should be able to depict soft tissue and osseous pathologies that are relevant to OA disease progression and clinical manifestations of OA. Magnetic resonance imaging (MRI) fulfills these criteria and advances in technology and increasing knowledge regarding imaging outcomes likely should play a more prominent role in DMOAD clinical trials. In this perspective article, we will describe MRI-based tools and analytic methods that can be applied to DMOAD clinical trials with a particular emphasis on knee OA. MRI should be the modality of choice for eligibility screening and outcome assessment. Optimal MRI pulse sequences must be chosen to visualize specific features of OA.

Potential metabolites of Arecaceae family for the natural anti-osteoarthritis medicine: A review

Osteoarthritis (OA) is a chronic inflammatory disorder of the joints caused by fluid and cartilage matrix component reduction. This disease results in symptoms of pain, deformity, and limitation of movement. In general, OA is treated with anti-inflammatory drugs and chondroprotection compounds, includes natural nutraceutical ingredients, which are expected to be effective and have minimal side effects. Arecaceae plants are widely spread worldwide, especially in tropical areas. The objective of this review is to collect information about the Arecaceae family as anti-OA agents, with the main study focusing on the primary and secondary metabolites of plants of the Arecaceae family, i.e., sugar palm (Arenga pinnata), nipa palm (Nypa fruticans), palmyra palm (Borassus flabellifer), date palm (Phoenix dactylifera), and betel nut (Areca catechu) have potential as anti-OA agents. The Arecaceae's metabolites that show anti-inflammatory and chondroprotective effects are galactomannan, fatty acids (linoleic and linolenic acids), flavonoids (quercetin, luteolin, isorhamnetin), phenolics (coumaric acid, ferulic acid), polyphenols (epicatechin), and steroids (stigmasterol, campesterol, spirostane). Based on the reports, the Arecaceae family plants become worthy of being explored and developed into natural anti-OA products, such as supplements or nutraceuticals.

Emerging pharmaceutical therapeutics and delivery technologies for osteoarthritis therapy

Osteoarthritis (OA) is one of the most common joint degenerative diseases in the world. At present, the management of OA depends on the lifestyle modification and joint replacement surgery, with the lifespan of prosthesis quite limited yet. Effective drug treatment of OA is essential. However, the current drugs, such as the non-steroidal anti-inflammatory drugs and acetaminophen, as well as glucosamine, chondroitin sulfate, hyaluronic acid, are accompanied by obvious side effects, with the therapeutic efficacy to be enhanced. Recently, novel reagents such as IL-1 antagonists and nerve growth factor inhibitors have entered clinical trials. Moreover, increasing evidence demonstrated that active ingredients of natural plants have great potential for treating OA. Meanwhile, the use of novel drug delivery strategies may overcome the shortcomings of conventional preparations and enhance the bioavailability of drugs, as well as decrease the side effects significantly. This review therefore summarizes the pathological mechanisms, management strategies, and research progress in the drug molecules including the newly identified active ingredient derived from medicinal plants for OA therapy, with the drug delivery technologies also summarized, with the expectation to provide the summary and outlook for developing the next generation of drugs and preparations for OA therapy.

Glucosamine Use Is Associated with a Higher Risk of Cardiovascular Diseases in Patients with Osteoarthritis: Results from a Large Study in 685,778 Subjects

Glucosamine is widely used around the world and as a popular dietary supplement and treatment in patients with osteoarthritis in China; however, the real-world cardiovascular risk of glucosamine in long-term use is still unclear. A retrospective, population-based cohort study was performed, based on the Beijing Medical Claim Data for Employees from 1 January 2010 to 31 December 2017. Patients newly diagnosed with osteoarthritis were selected and divided into glucosamine users and non- glucosamine users. The glucosamine users group was further divided into adherent, partially adherent, and non-adherent groups according to the medication adherence. New-onset cardiovascular diseases (CVD) events, coronary heart diseases (CHD), and stroke, were identified during the observational period. COX proportional regression models were used to estimate the risks. Of the 685,778 patients newly diagnosed with osteoarthritis including 240,419 glucosamine users and 445,359 non-users, the mean age was 56.49 (SD: 14.45) years and 59.35% were females. During a median follow-up of 6.13 years, 64,600 new-onset CVD, 26,530 CHD, and 17,832 stroke events occurred. Glucosamine usage was significantly associated with CVD (HR: 1.10; 95% CI: 1.08−1.11) and CHD (HR: 1.12; 95% CI: 1.09−1.15), but not with stroke (HR: 1.03; 95% CI: 0.99−1.06). The highest CVD risk was shown in the adherent group (HR: 1.68; 95% CI: 1.59−1.78), followed by the partially adherent group (HR: 1.26, 95% CI: 1.22−1.30), and the non-adherent group (HR: 1.03; 95% CI: 1.02−1.05), with a significant dose−response relationship (p-trend < 0.001). In this longitudinal study, adherent usage of glucosamine was significantly associated with a higher risk for cardiovascular diseases in patients with osteoarthritis.

Efficacy of the use of chondroitin sulphate and glucosamine for the treatment of temporomandibular joint dysfunction: A systematic review and meta-analysis

OBJECTIVE

To evaluate the efficacy of chondroitin sulfate (CS) and glucosamine (GS), the most relevant drugs of "Symptomatic Slow Acting Drug for Osteoarthritis" (SYSADOA), in the functional and symptomatic improvement of temporomandibular dysfunction. Although, controversy exists regarding their benefit.

METHODS

An electronic search was conducted to retrieve randomized controlled clinical trials (RCTs). The risk of bias assessment was evaluated using the Cochrane Collaboration's tool. Data were meta-analyzed with a random effect model whenever possible.

RESULTS

Three RCTs were included. Qualitative results showed a decrease in pain, joint noise, and inflammatory biomarkers in synovial fluid and an improvement in maximum mouth opening without significant adverse effects. Meta-analysis showed a significant increase in maximum mouth opening with the use of CS-GS (p = 0.19). No statistically significant differences were found in pain reduction compared to tramadol.

CONCLUSION

CS-GS is effective and safe in the symptomatic and functional improvement of patients with TMD.

Injectable Natural Polymer Hydrogels for Treatment of Knee Osteoarthritis

Osteoarthritis (OA) is a serious chronic and degenerative disease that increasingly occurs in the aged population. Its current clinical treatments are limited to symptom relief and cannot regenerate cartilage. Although a better understanding of OA pathophysiology has been facilitating the development of novel therapeutic regimen, delivery of therapeutics to target sites with minimal invasiveness, high retention, and minimal side effects remains a challenge. Biocompatible hydrogels have been recognized to be highly promising for controlled delivery and release of therapeutics and biologics for tissue repair. In this review, the current approaches and the challenges in OA treatment, and unique properties of injectable natural polymer hydrogels as delivery system to overcome the challenges are presented. The common methods for fabrication of injectable polysaccharide-based hydrogels and the effects of their composition and properties on the OA treatment are detailed. The strategies of the use of hydrogels for loading and release cargos are also covered. Finally, recent efforts on the development of injectable polysaccharide-based hydrogels for OA treatment are highlighted, and their current limitations are discussed.

Connection between Mesenchymal Stem Cells Therapy and Osteoclasts in Osteoarthritis

The use of mesenchymal stem cells constitutes a promising therapeutic approach, as it has shown beneficial effects in different pathologies. Numerous in vitro, pre-clinical, and, to a lesser extent, clinical trials have been published for osteoarthritis. Osteoarthritis is a type of arthritis that affects diarthritic joints in which the most common and studied effect is cartilage degradation. Nowadays, it is known that osteoarthritis is a disease with a very powerful inflammatory component that affects the subchondral bone and the rest of the tissues that make up the joint. This inflammatory component may induce the differentiation of osteoclasts, the bone-resorbing cells. Subchondral bone degradation has been suggested as a key process in the pathogenesis of osteoarthritis. However, very few published studies directly focus on the activity of mesenchymal stem cells on osteoclasts, contrary to what happens with other cell types of the joint, such as chondrocytes, synoviocytes, and osteoblasts. In this review, we try to gather the published bibliography in relation to the effects of mesenchymal stem cells on osteoclastogenesis. Although we find promising results, we point out the need for further studies that can support mesenchymal stem cells as a therapeutic tool for osteoclasts and their consequences on the osteoarthritic joint.

Conservative Trio-Therapy for Varus Knee Osteoarthritis: A Prospective Case-Study

Background and Objectives: Knee osteoarthritis (OA) is a frequent cause of pain, functional limitations, and a common reason for surgical treatment, such as joint replacement. Conservative therapies can reduce pain and improve function; thus, delaying or even preventing surgical intervention. Various individual conservative therapies show benefits, but combination therapies remain underexplored. The aim of this prospective case-study was to assess the effect of a conservative combination therapy in patients with painful varus knee OA. Materials and Methods: With strong inclusion and exclusion criteria, nine patients with painful varus knee OA (mean age 56 years (range 51−63 years) were selected and monitored over six months, using the following clinical outcome scores: pain visual analog scale (VAS), Western Ontario and McMaster Universities osteoarthritis index (WOMAC score), short-form−36 items (SF-36) quality of life score, and the sports frequency score. All patients received a standardized conservative trio-therapy with varus-reducing hindfoot shoe-insoles with a lateral hindfoot wedge, oral viscosupplementation, and physiotherapy for six months. Results: The pain was reduced significantly from initial VAS values of 5.4 points (range, 3−10) to values of 0.6 points (range, 0−3; p < 0.01), at the end of treatment. After six months, seven out of nine patients reported no pain at all (VAS 0). The WOMAC score improved significantly, from initial values of 35 (range, 10−56) to values of 2 (range, 0−9; p < 0.01). The SF-36 score showed significant improvement after six months in all four domains of physical health (p < 0.01) and in two of the four domains of mental health (p < 0.05). The sports frequency score increased by at least one level in six out of nine patients after six months. Conclusions: The conservative trio-therapy in patients with varus knee OA showed positive initial clinical results: less pain, higher function, better quality of life, and higher sport activity. Further studies are required to evaluate the long-term effect.

Heterologous production of chondroitin

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Chondroitin sulfate (CS) is a glycosaminoglycan with a growing variety of applications.

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CS can be produced from microbial fermentation of native or engineered strains.

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Synthetic biology tools are being used to improve CS yields in different hosts.

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Integrated polymerization and sulfation can generate cost-effective CS.

Chondroitin sulfate (CS) is a glycosaminoglycan with a broad range of applications being a popular dietary supplement for osteoarthritis. Usually, CS is extracted from animal sources. However, the known risks of animal products use have been driving the search for alternative methods and sources to obtain this compound. Several pathogenic bacteria naturally produce chondroitin-like polysaccharides through well-known pathways and, therefore, have been the basis for numerous studies that aim to produce chondroitin using non-pathogenic hosts. However, the yields obtained are not enough to meet the high demand for this glycosaminoglycan. Metabolic engineering strategies have been used to construct improved heterologous hosts. The identification of metabolic bottlenecks and regulation points, and the screening for efficient enzymes are key points for constructing microbial cell factories with improved chondroitin yields to achieve industrial CS production. The recent advances on enzymatic and microbial strategies to produce non-animal chondroitin are herein reviewed. Challenges and prospects for future research are also discussed.

Overview of First-Line and Second-Line Pharmacotherapies for Osteoarthritis with Special Focus on Intra-Articular Treatment

Osteoarthritis (OA) can be defined as the result of pathological processes of various etiologies leading to damage to the articular structures. Although the mechanism of degenerative changes has become better understood due to the plethora of biochemical and genetic studies, the drug that could stop the degenerative cascade is still unknown. All available forms of OA therapy are based on symptomatic treatment. According to actual guidelines, comprehensive treatment of OA should always include a combination of various therapeutic options aimed at common goals, which are pain relief in the first place, and then the improvement of function. Local treatment has become more common practice, which takes place between rehabilitation and pharmacological treatment in the hierarchy of procedures. Only in the case of no improvement and the presence of advanced lesions visible in imaging tests, should surgery be considered. Currently, an increasing number of studies are being published suggesting that intra-articular injections may be as effective or even more effective than non-steroidal anti-inflammatory drugs (NSAIDs) and result in fewer systemic adverse events. The most commonly used preparations are hyaluronic acid (HA), glucocorticosteroids (GS), and also platelet-rich plasma (PRP) in recent years. This review aims to present the mechanism of action and clinical effectiveness of different pharmacological options in relieving pain and improving functions in OA as well as the emerging approach in intra-articular treatment with PRP.

O-GlcNAcylation drives calcium signaling toward osteoblast differentiation: A bioinformatics-oriented study

This study aimed to reveal the possible mechanisms by which O-linked-N-acetylglucosaminylation (O-GlcNAcylation) regulates osteoblast differentiation using a series of bioinformatics-oriented experiments. To examine the influence of O-GlcNAcylation levels on osteoblast differentiation, osteoblastic MC3T3-E1 cells were treated with O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) inhibitors. Correlations between the levels of O-GlcNAcylation and the expression of osteogenic markers as well as OGT were evaluated by qPCR and western blotting. The O-GlcNAcylated proteins assumed to correlate with Runx2 expression were retrieved from several public databases and used for further bioinformatics analysis. Following the findings of the bioinformatics analysis, intracellular calcium ([Ca²⁺ ]_i ) was monitored in the cells treated with OGT and OGA inhibitors using a confocal laser-scanning microscope (CLS). The interaction effect between O-GlcNAcylation and [Ca²⁺ ]_i on osteogenic marker expression was determined using stable OGT knockdown MC3T3-E1 cells. O-GlcNAcylation was positively associated with osteoblast differentiation. The time-course profile of global O-GlcNAcylated proteins showed a distinctive pattern with different molecular weights during osteoblast differentiation. The expression pattern of several O-GlcNAcylated proteins was significantly similar to that of Runx2 expression. Bioinformatic analysis of the retrieved Runx2-related-O-GlcNAcylated-proteins revealed the importance of [Ca²⁺ ]_i . CLS showed that alteration of O-GlcNAcylation rapidly changed [Ca²⁺ ]_i in MC3T3-E1 cells. O-GlcNAcylation and [Ca²⁺ ]_i showed an interaction effect on the expression of osteogenic markers. OGT knockdown disrupted the [Ca²⁺ ]_i -induced expression changes of osteogenic markers. O-GlcNAcylation interacts with [Ca²⁺ ]_i and elicits osteoblast differentiation by regulating the expression of osteogenic markers.

Pain management in hemophilia: expert recommendations

INTRODUCTION

As a typical consequence of bleeding into muscles and joints, patients with severe hemophilia suffer from acute and chronic pain. In spite of its high prevalence, pain in this patient group is not always sufficiently considered or treated in an effective manner.

AIM

The recommendations presented in this paper address possible improvements in pain management in hemophilia patients and particularities that have to be taken into account in this patient group.

METHOD

The manifold aspects of pain management in hemophilia patients were discussed within the framework of an expert meeting. Based on the available literature and the experts' clinical experience, the participants developed a set of recommendations presented in this paper.

RESULTS

Pain management in patients with hemophilia is often insufficient, a fact that not only influences the patients' quality of life but also implies the risk of difficult to manage chronic pain. Both the prevalent polypharmacy (due to comorbidities) as well as the underlying disease itself present special challenges to pain therapy in this patient group. The present review and recommendations are intended to support medical professionals in recognising the risks of pain chronicity, applying basic principles of multimodal pain therapy, including the options of psychological intervention and modalities of physical medicine in therapy concepts, and reaching a comprehensive understanding of the range of analgesic options available.

Evidence, Efficasy and Safety of the Chondroprotective Parapharmaceuticals in Treatment of the Early Stages of Osteoarthritis

Osteoarthritis (OA) is the most common joint disease that significantly affects the patients’ quality of life and requires significant medical and social investments for treatment and rehabilitation. There are no therapeutic agents which would be able to regenerate lost or damaged hyaline cartilage. The objective: to assess the efficacy and safety of the chondroprotective parapharmaceutical agent Flexogial in the complex treatment of patients with initial stages of the knee ОА. Materials and methods. 12-weeks study was conducted with the participation of 60 patients with knee OA aged 53,7±2,9 years, women – 36 (60%), men – 24 (40%) with the initial stages of the disease (I–II radiological stage). The main clinical group consisted of 30 patients who took the chondroprotective complex agent Flexogial 15 ml once a day; the comparison group included 30 patients who were administered glucosamine sulfate 1500 mg in a monopreparation taken once a day. Efficacy of the treatment was evaluated using the VAS scale, Tegner’s scale, Lisholm scale at the beginning of treatment, after 6 and 12 weeks in dynamics with subsequent statistical processing of the results. Results. The study demonstrated better indicators of functional activity and less pain intensity in the affected joints in patients of the main group who took the parapharmaceutical agent Flexogial compared to the group of patients who took glucosamine monopreparation with the same number of registered adverse events in both groups of patients (5%). Conclusions. The results of the presented clinical study proved the advantage of use of the combined chondroprotective drinking complex Flexogial in comparison with the monopharmaceutical preparation glucosamine sulfate in the treatment of patients with early stages knee OA in terms of the effect on the intensity of pain and improvement in the parameters of the functional activity of patients after 6 and 12 weeks with the same frequency of registered adverse events.

How to effectively utilize imaging in disease-modifying treatments for osteoarthritis clinical trials: the radiologist's perspective

Introduction: One of the reasons for failures of disease-modifying osteoarthritis drug clinical trials has been the radiography-based definition of structural eligibility criteria. Imaging, particularly MRI, has a critical role in planning and conducting clinical trials of osteoarthritis.Areas covered: A literature search was performed using keywords including 'osteoarthritis,' 'knee,' 'MRI,' 'intra-articular injection,' 'semiquantitative scoring,' 'clinical trial,' and other specific terms where relevant. The core concepts of using MRI in osteoarthritis clinical trials are explained focusing on knee osteoarthritis, including its role in determining patient eligibility and inclusion/exclusion criteria as well as outcome measures from the expert musculoskeletal radiologist's perspective. A brief overview of statistical analyses that should be deployed in clinical trials utilizing semiquantitative MRI analyses is discussed.Expert opinion: In order to increase chances to detect measurable efficacy effects, investigators should consider utilizing MRI from screening to outcome assessment. Recognition of several phenotypes of osteoarthritis helps in participant stratification and will lead to more targeted clinical trials. Inclusion and exclusion criteria need to be defined using not only radiography but also MRI. Correct intra-articular injection of investigational compounds is critically important if intra-articular drug delivery is required, and such procedure should be performed and documented using appropriate imaging guidance.

Recent Progress in Cartilage Lubrication

Healthy articular cartilage, covering the ends of bones in major joints such as hips and knees, presents the most efficiently-lubricated surface known in nature, with friction coefficients as low as 0.001 up to physiologically high pressures. Such low friction is indeed essential for its well-being. It minimizes wear-and-tear and hence the cartilage degradation associated with osteoarthritis, the most common joint disease, and, by reducing shear stress on the mechanotransductive, cartilage-embedded chondrocytes (the only cell type in the cartilage), it regulates their function to maintain homeostasis. Understanding the origins of such low friction of the articular cartilage, therefore, is of major importance in order to alleviate disease symptoms, and slow or even reverse its breakdown. This progress report considers the relation between frictional behavior and the cellular mechanical environment in the cartilage, then reviews the mechanism of lubrication in the joints, in particular focusing on boundary lubrication. Following recent advances based on hydration lubrication, a proposed synergy between different molecular components of the synovial joints, acting together in enabling the low friction, has been proposed. Additionally, recent development of natural and bio-inspired lubricants is reviewed.

[Reduction of social coverage for symptomatic slow-acting drugs for osteoarthritis: a disinvestment initiative in Argentina, 2015-2017]

In April 2016, the National Institute of Social Services for Retirees and Pensioners discontinued its policy of 100% coverage for 159 drugs (the "social subsidy"), including symptomatic slow-acting drugs for osteoarthritis (SYSADOAs), due to insufficient evidence of significant clinical benefit. We evaluated the effect of this measure on the use of SYSADOAs as well as non-steroidal anti-inflammatory drugs (NSAIDs), which were unaffected by this policy change. We compared outpatient dispensations of SYSADOAs and NSAIDs from 2015 to 2017, measuring dispensed units, retail price, and out-of-pocket expenses for beneficiaries each month. After the change in coverage, there was a 61.6% total decrease in SYSADOA units dispensed, and a 63.4% decrease in the final sales price to the public, measured in constant values. Dispensation was not reoriented towards NSAIDs, which fell by 6.1%. The incidence of new treatments decreased (from 6.4 to 3.3 treatments per 1,000 beneficiaries per month), as did their continuity. Beneficiaries' out-of-pocket spending on SYSADOAs increased by 75.8% (at constant values). Disinvestment in interventions with questionable therapeutic value is an important tool in working toward the sustainability of health systems.

Glucosamine and Chondroitin Use in Relation to C-Reactive Protein Concentration: Results by Supplement Form, Formulation, and Dose

Objectives: Glucosamine and chondroitin supplements have been associated with reduced inflammation, as measured by C-reactive protein (CRP). It is unclear if associations vary by formulation (glucosamine alone vs. glucosamine+chondroitin), form (glucosamine hydrochloride vs. glucosamine sulfate), or dose. Design, Subjects, Setting, Location: The authors evaluated these questions using cross-sectional data collected between 1999 and 2010 on 21,917 US adults, surveyed as part of the National Health and Nutrition Examination Survey (NHANES). Exposures: Glucosamine and chondroitin use was assessed during an in-home interview; exposures include supplement formulation, form, and dose. Outcome/Analysis: CRP was measured using blood collected at interview. Survey-weighted linear regression was used to evaluate the multivariable-adjusted association between exposures and log-transformed CRP. Results: In early years (1999-2004), use of glucosamine (ratio = 0.87; 95% confidence interval [CI] = 0.79-0.96) and chondroitin (ratio = 0.83; 95% CI = 0.72-0.95) was associated with reduced CRP. However, associations significantly varied by calendar time (p-interaction = 0.04 and p-interaction = 0.01, respectively), with associations nonsignificant in later years (ratio = 1.09; 95% CI = 0.94-1.28 and ratio = 1.16; 95% CI = 0.99-1.35, respectively). Consequently, all analyses have been stratified by calendar time. Associations did not significantly differ by formulation in either set of years; however, significant associations were observed for combined use of glucosamine+chondroitin (ratio_early = 0.82; 95% CI = 0.72-0.95; ratio_late = 1.16; 1.00-1.35), but not glucosamine alone. Associations also did not significantly differ by supplement form. Even so, a significant inverse association was observed only for glucosamine sulfate in the early years (ratio = 0.78; 95% CI = 0.64-0.95); no significant association was observed for glucosamine hydrochloride. No significant trends were observed by dose. Conclusions: Although a significant inverse association was observed for glucosamine and chondroitin and CRP in early years, this association did not hold in later years. This pattern held for combined use of glucosamine+chondroitin as well as glucosamine sulfate, although associations did not significantly vary by supplement form, formulation, or dose. Further study is needed to better understand these associations in the context of calendar time.

Treatment of knee osteoarthritis with a new formulation of a fixed-dose combination of glucosamine sulfate and bovine chondroitin: a multicenter, randomized, single-blind, non-inferiority clinical trial

OBJECTIVES

To compare the efficacy and safety of a new formulation of a fixed dose combination of glucosamine sulfate (GS; 1500 mg) and bovine chondroitin sulfate (CS; 1200 mg) versus the reference product (RP) in patients with knee osteoarthritis (OA).

METHODS

In this multicenter, randomized, single-blind trial, 627 patients with knee osteoarthritis (OA)-Kellgren-Lawrence grades 2 or 3 and mean score ≥ 40 mm in the WOMAC pain subscale-were randomized to receive GS/CS or the RP for 24 weeks. The primary efficacy endpoint was the absolute change in WOMAC pain subscale score. The secondary endpoints included the following: WOMAC total and subscale scores, overall assessment of the disease by the patient and the investigator, SF-12 score, OMERACT-OARSI response rate to the treatment, and rescue medication use.

RESULTS

Mean reductions of WOMAC pain score were - 35.1 (sd = 23.2) mm in the GS/CS group and - 36.5 (sd = 24.9) mm in the RP group. The difference between the adjusted means of both treatments confirmed the non-inferiority of GS/CS versus the RP. Improvement was observed in pain, stiffness, physical function and total WOMAC score, as well as in overall OA assessment by the patient and the investigator for both groups. No improvement was observed in SF-12. The rate of OMERACT-OARSI responders was 89.4% in GS/CS group and 87.9% in the RP group. Headache and changes in glucose tolerance were the most frequent treatment-related adverse events.

CONCLUSIONS

The new formulation of a fixed-dose combination of glucosamine sulfate and bovine chondroitin sulfate was non-inferior to the RP in symptomatic treatment of knee OA, with a high responder rate and good tolerability profile.

TRIAL REGISTRATION

ClinicalTrials.gov; Registration number NCT02830919 ; Date of registration: July 13, 2016; First randomization date: December 05, 2016).

Hyaluronic acid and chondroitin sulfate (meth)acrylate-based hydrogels for tissue engineering: Synthesis, characteristics and pre-clinical evaluation

Hydrogels based on photocrosslinkable Hyaluronic Acid Methacrylate (HAMA) and Chondroitin Sulfate Methacrylate (CSMA) are presently under investigation for tissue engineering applications. HAMA and CSMA gels offer tunable characteristics such as tailorable mechanical properties, swelling characteristics, and enzymatic degradability. This review gives an overview of the scientific literature published regarding the pre-clinical development of covalently crosslinked hydrogels that (partially) are based on HAMA and/or CSMA. Throughout the review, recommendations for the next steps in clinical translation of hydrogels based on HAMA or CSMA are made and potential pitfalls are defined. Specifically, a myriad of different synthetic routes to obtain polymerizable hyaluronic acid and chondroitin sulfate derivatives are described. The effects of important parameters such as degree of (meth)acrylation and molecular weight of the synthesized polymers on the formed hydrogels are discussed and useful analytical techniques for their characterization are summarized. Furthermore, the characteristics of the formed hydrogels including their enzymatic degradability are discussed. Finally, a summary of several recent applications of these hydrogels in applied fields such as cartilage and cardiac regeneration and advanced tissue modelling is presented.

Glucosamine and Chondroitin Supplements and Risk of Colorectal Adenoma and Serrated Polyp

BACKGROUND

Studies have shown an inverse association between use of glucosamine and chondroitin supplements and colorectal cancer risk. However, the association with the precursor lesion, colorectal adenoma and serrated polyp, has not been examined.

METHODS

Analyses include 43,163 persons from the Nurses' Health Study (NHS), Health Professionals Follow-up Study (HPFS), and NHS2 who reported on glucosamine/chondroitin use in 2002 and who subsequently underwent ≥1 lower gastrointestinal endoscopy. By 2012, 5,715 conventional (2,016 high-risk) adenomas were detected, as were 4,954 serrated polyps. Multivariable logistic regression for clustered data was used to calculate OR and 95% confidence intervals (CI).

RESULTS

Glucosamine/chondroitin use was inversely associated with high risk and any conventional adenoma in NHS and HPFS: in the pooled multivariable-adjusted model, glucosamine + chondroitin use at baseline was associated with a 26% (OR = 0.74; 95% CI, 0.60-0.90; P _{heterogeneity} = 0.23) and a 10% (OR = 0.90; 95% CI, 0.81-0.99; P _{heterogeneity} = 0.36) lower risk of high-risk adenoma and overall conventional adenoma, respectively. However, no association was observed in NHS2, a study of younger women (high-risk adenoma: OR = 1.09; 95% CI, 0.82-1.45; overall conventional adenoma: OR = 1.00; 95% CI, 0.86-1.17), and effect estimates pooled across all three studies were not significant (high-risk: OR = 0.83; 95% CI, 0.63-1.10; P _{heterogeneity} = 0.03; overall conventional adenoma: OR = 0.93; 95% CI, 0.85-1.02; P _{heterogeneity} = 0.31). No associations were observed for serrated polyps.

CONCLUSIONS

Glucosamine/chondroitin use was associated with lower risks of high-risk and overall conventional adenoma in older adults; however, this association did not hold in younger women, or for serrated polyps.

IMPACT

Our study suggests that glucosamine and chondroitin may act on early colorectal carcinogenesis in older adults.

Risk factors for pain and functional impairment in people with knee and hip osteoarthritis: a systematic review and meta-analysis

OBJECTIVE

To identify risk factors for pain and functional deterioration in people with knee and hip osteoarthritis (OA) to form the basis of a future 'stratification tool' for OA development or progression.

DESIGN

Systematic review and meta-analysis.

METHODS

An electronic search of the literature databases, Medline, Embase, CINAHL, and Web of Science (1990-February 2020), was conducted. Studies that identified risk factors for pain and functional deterioration to knee and hip OA were included. Where data and study heterogeneity permitted, meta-analyses presenting mean difference (MD) and ORs with corresponding 95% CIs were undertaken. Where this was not possible, a narrative analysis was undertaken. The Downs & Black tool assessed methodological quality of selected studies before data extraction. Pooled analysis outcomes were assessed and reported using the Grading of Reccomendation, Assessment, Development and Evaluation (GRADE) approach.

RESULTS

82 studies (41 810 participants) were included. On meta-analysis: there was moderate quality evidence that knee OA pain was associated with factors including: Kellgren and Lawrence≥2 (MD: 2.04, 95% CI 1.48 to 2.81; p<0.01), increasing age (MD: 1.46, 95% CI 0.26 to 2.66; p=0.02) and whole-organ MRI scoring method (WORMS) knee effusion score ≥1 (OR: 1.35, 95% CI 0.99 to 1.83; p=0.05). On narrative analysis: knee OA pain was associated with factors including WORMS meniscal damage ≥1 (OR: 1.83). Predictors of joint pain in hip OA were large acetabular bone marrow lesions (BML; OR: 5.23), chronic widespread pain (OR: 5.02) and large hip BMLs (OR: 4.43).

CONCLUSIONS

Our study identified risk factors for clinical pain in OA by imaging measures that can assist in predicting and stratifying people with knee/hip OA. A 'stratification tool' combining verified risk factors that we have identified would allow selective stratification based on pain and structural outcomes in OA.

PROSPERO REGISTRATION NUMBER

CRD42018117643.

An updated algorithm recommendation for the management of knee osteoarthritis from the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO)

OBJECTIVES

The European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) sought to revisit the 2014 algorithm recommendations for knee osteoarthritis (OA), in light of recent efficacy and safety evidence, in order to develop an updated stepwise algorithm that provides practical guidance for the prescribing physician that is applicable in Europe and internationally.

METHODS

Using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) process, a summary of evidence document for each intervention in OA was provided to all members of an ESCEO working group, who were required to evaluate and vote on the strength of recommendation for each intervention. Based on the evidence collected, and on the strength of recommendations afforded by consensus of the working group, the final algorithm was constructed.

RESULTS

An algorithm for management of knee OA comprising a stepwise approach and incorporating consensus on 15 treatment recommendations was prepared by the ESCEO working group. Both "strong" and "weak" recommendations were afforded to different interventions. The algorithm highlights the continued importance of non-pharmacological interventions throughout the management of OA. Benefits and limitations of different pharmacological treatments are explored in this article, with particular emphasis on safety issues highlighted by recent literature analyses.

CONCLUSIONS

The updated ESCEO stepwise algorithm, developed by consensus from clinical experts in OA and informed by available evidence for the benefits and harms of various treatments, provides practical, current guidance that will enable clinicians to deliver patient-centric care in OA practice.

Recent advance in delivery system and tissue engineering applications of chondroitin sulfate

Chondroitin sulfate (CS) is a naturally derived bioactive macromolecule and the major component of extracellular matrix (ECM), which widely distributed in various organisms and has attracted much attention due to their significant bioactivities. It is regarded as a favorable biomaterial that has been applied extensively in field of drug delivery and tissue engineering due to its property of non-poisonous, biodegradation, biocompatible and as a major component of ECM. The present article reviews the structure and bioactivities of CS, from the preparation to structure analysis, and emphatically focuses on the biomaterial exertion in delivery system and tissue engineering. At the same time, the present application status and prospect of CS are analyzed and the biomaterial exertion of CS in delivery system and various tissue engineering are also comparatively discussed in view of biomaterial development.

Galactosaminoglycans: Medical Applications and Drawbacks

Galactosaminoglycans (GalAGs) are sulfated glycans composed of alternating N-acetylgalactosamine and uronic acid units. Uronic acid epimerization, sulfation patterns and fucosylation are modifications observed on these molecules. GalAGs have been extensively studied and exploited because of their multiple biomedical functions. Chondroitin sulfates (CSs), the main representative family of GalAGs, have been used in alternative therapy of joint pain/inflammation and osteoarthritis. The relatively novel fucosylated chondroitin sulfate (FCS), commonly found in sea cucumbers, has been screened in multiple systems in addition to its widely studied anticoagulant action. Biomedical properties of GalAGs are directly dependent on the sugar composition, presence or lack of fucose branches, as well as sulfation patterns. Although research interest in GalAGs has increased considerably over the three last decades, perhaps motivated by the parallel progress of glycomics, serious questions concerning the effectiveness and potential side effects of GalAGs have recently been raised. Doubts have centered particularly on the beneficial functions of CS-based therapeutic supplements and the potential harmful effects of FCS as similarly observed for oversulfated chondroitin sulfate, as a contaminant of heparin. Unexpected components were also detected in CS-based pharmaceutical preparations. This review therefore aims to offer a discussion on (1) the current and potential therapeutic applications of GalAGs, including those of unique features extracted from marine sources, and (2) the potential drawbacks of this class of molecules when applied to medicine.

Recommendations for the Reporting of Harms in Manuscripts on Clinical Trials Assessing Osteoarthritis Drugs: A Consensus Statement from the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO)

BACKGROUND

There is strong evidence of under-reporting of harms in manuscripts on randomized controlled trials (RCTs) compared with the volume of raw data retrieved from these trials. Many guidelines have been developed to tackle this, but they have failed to address some important issues that would allow for standardization and transparency. As a consequence, harms reporting in manuscripts remains suboptimal.

OBJECTIVE

The European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) aimed to deliver accurate recommendations for better reporting of harms in clinical trials manuscripts on anti-osteoarthritis (OA) drugs. These could help to better inform clinicians on harms recorded in RCTs and further help researchers conducting meta-analyses.

METHODS

Using the outcomes of several systematic reviews on the safety of anti-OA drugs, we summarized the ways in which harms have been reported in OA RCT manuscripts to date. Next, we drafted some recommendations and initiated a modified Delphi process that involved a panel of clinicians and clinical researchers to build an expert consensus on recommendations from the ESCEO for the reporting of harms in future manuscripts on RCTs assessing anti-OA drugs.

RESULTS

These recommendations emphasize that all treatment-emergent adverse events (AEs) should always be taken into account for harms reporting, with no frequency threshold, and describe how specific AEs should be reported; they also provide a list of the most relevant organ systems to be considered according to each class of drug for reporting of harms within the results section of a manuscript. Irrespective of the drug, the ESCEO recommends that total, severe and serious AEs and withdrawals due to AEs should always be reported; guidance on the reporting of specific events pertaining to each category is provided. The ESCEO also recommends the reporting of information on drug effect on biological parameters, with specific guidance.

CONCLUSIONS

These recommendations may contribute to improve transparency in the field of safety of anti-OA medications. Pharmaceutical companies developing drugs for OA, and researchers conducting clinical trials, are encouraged to comply with them when reporting harms-related results in manuscripts on RCTs. The ESCEO also encourages journals to refer to the ESCEO recommendations in their instructions to authors for the publication of manuscripts on trials of anti-OA medications.

Safety of Symptomatic Slow-Acting Drugs for Osteoarthritis: Outcomes of a Systematic Review and Meta-Analysis

BACKGROUND

Symptomatic slow-acting drugs for osteoarthritis (SYSADOAs) are an important drug class in the treatment armamentarium for osteoarthritis (OA).

OBJECTIVE

We aimed to re-assess the safety of various SYSADOAs in a comprehensive meta-analysis of randomized placebo-controlled trials, using, as much as possible, data from full safety reports.

METHODS

We performed a systematic review and random-effects meta-analyses of randomized, double-blind, placebo-controlled trials that assessed adverse events (AEs) with various SYSADOAs in patients with OA. The databases MEDLINE, Cochrane Central Register of Controlled Trials (Ovid CENTRAL) and Scopus were searched. The primary outcomes were overall severe and serious AEs, as well as AEs involving the following Medical Dictionary for Regulatory Activities (MedDRA) system organ classes (SOCs): gastrointestinal, cardiac, vascular, nervous system, skin and subcutaneous tissue, musculoskeletal and connective tissue, renal and urinary system.

RESULTS

Database searches initially identified 3815 records. After exclusions according to the selection criteria, 25 studies on various SYSADOAs were included in the qualitative synthesis, and 13 studies with adequate data were included in the meta-analyses. Next, from the studies previously excluded according to the protocol, 37 with mainly oral nonsteroidal anti-inflammatory drugs (NSAIDs) permitted as concomitant medication were included in a parallel qualitative synthesis, from which 18 studies on various SYSADOAs were included in parallel meta-analyses. This post hoc parallel inclusion was conducted because of the high number of studies allowing concomitant anti-OA medications. Indeed, primarily excluding studies with concomitant anti-OA medications was crucial for a meta-analysis on safety. The decision for parallel inclusion was made for the purpose of comparative analyses. Glucosamine sulfate (GS), chondroitin sulfate (CS) and avocado soybean unsaponifiables (ASU; Piascledine®) were not associated with increased odds for any type of AEs compared with placebo. Overall, with/without concomitant OA medication, diacerein was associated with significantly increased odds of total AEs (odds ratio [OR] 2.22; 95% confidence interval [CI] 1.58-3.13; I2 = 52.8%), gastrointestinal disorders (OR 2.85; 95% CI 2.02-4.04; I2 = 62.8%) and renal and urinary disorders (OR 3.42; 95% CI 2.36-4.96; I2 = 17.0%) compared with placebo. In studies that allowed concomitant OA medications, diacerein was associated with significantly more dermatological disorders (OR 2.47; 95% CI 1.42-4.31; I2 = 0%) and more dropouts due to AEs (OR 3.18; 95% CI 1.85-5.47; I2 = 13.4%) than was placebo. No significant increase in serious or severe AEs was found with diacerein versus placebo.

CONCLUSIONS

GS and CS can be considered safe treatments for patients with OA. All eligible studies on ASU included in our analysis used the proprietary product Piascledine® and allowed other anti-OA medications; thus, the safety of ASU must be confirmed in future studies without concomitant anti-OA medications. Given the safety concerns with diacerein, its usefulness in patients with OA should be assessed, taking into account individual patient characteristics.

Active viscosupplements for osteoarthritis treatment

OBJECTIVE

Osteoarthritis is a chronic, painful and disabling disease which prevalence is increasing in developing countries. Patients with osteoarthritis present a reduced synovial fluid viscoelasticity due to a reduction in concentration and molecular weight of hyaluronic acid. Currently, the main treatment used to restore the compromised rheological properties of synovial fluid is the viscosupplementation by hyaluronic acid injections that can be combined with oral anti-inflammatory drugs for pain relief. Combination of viscosupplements with chemical agents or drugs is emerging as a new strategy to provide a double action of synovial fluid viscoelasticity recovery and the therapeutic effect of the bioactive principle.

METHODS

In this review, we present the latest research on the combination of viscosupplements with active molecules. We conducted a literature review of articles published in different web search engines and categorized according to the active molecule introduced into the viscosupplement.

RESULTS

Generally, the introduction of anti-inflammatory molecules have shown to improve pain relief although some cytotoxicity has been demonstrated especially for non-steroidal anti-inflammatory drugs. Other molecules such as antioxidant or disease modifying osteoarthritis drugs have been reported to improve viscosupplementation action. Drug delivery systems combined with hyaluronic acid could enhance the activity of the encapsulated molecules and provide better control over the drug release. Finally, biological approaches such as the use of stem cells or platelet-rich plasma seem to be the most promising strategies for cartilage recovery.

CONCLUSIONS

Combination therapy of viscosupplements with therapeutic agents, drug delivery systems or regenerative therapies can improve viscosupplementation outcome in terms of pain relief and joint functionality. However, further research is needed in order to reach more conclusive results.

Placebo Effect in the Treatment of Depression and Anxiety

The aim of this review is to evaluate the placebo effect in the treatment of anxiety and depression. Antidepressants are supposed to work by fixing a chemical imbalance, specifically, a lack of serotonin or norepinephrine in the brain. However, analyses of the published and the unpublished clinical trial data are consistent in showing that most (if not all) of the benefits of antidepressants in the treatment of depression and anxiety are due to the placebo response, and the difference in improvement between drug and placebo is not clinically meaningful and may be due to breaking blind by both patients and clinicians. Although this conclusion has been the subject of intense controversy, the current article indicates that the data from all of the published meta-analyses report the same results. This is also true of recent meta-analysis of all of the antidepressant data submitted to the Food and Drug Administration (FDA) in the process of seeking drug approval. Also, contrary to previously published results, the new FDA analysis reveals that the placebo response has not increased over time. Other treatments (e.g., psychotherapy and physical exercise) produce the same benefits as antidepressants and do so without the side effects and health risks of the active drugs. Psychotherapy and placebo treatments also show a lower relapse rate than that reported for antidepressant medication.

CTX-II and YKL-40 in early diagnosis and treatment evaluation of osteoarthritis

This study investigated the value of C-terminal telopeptides of collagen type II (CTX-II) and YKL-40 in early diagnosis and treatment evaluation of osteoarthritis (OA). A total of 90 patients with OA diagnosed and treated in The First Affiliated Hospital, Guangzhou Medical University from March 2015 to January 2018 were selected as the study group. At the same time, 50 healthy elderly were included as the control group. The study group was divided into three subgroups including group A (29 cases, 500 mg glucosamine sulfate), group B (29 cases, 50 mg diacerein) and group C (32 cases, 500 mg glucosamine sulfate and 50 mg diacerein). Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) was used to assess the severity and treatment of arthritis. Enzyme-linked immunosorbent assay was used to measure the concentration of CTX-II and YKL-40 in serum. WOMAC scores in the study A, B and C groups were significantly higher than those in the control group (P<0.001). Serum CTX-II and YKL-40 concentrations were higher in the study group than in the control group (P<0.001). Sensitivity of serum CTX-II combined with YKL-40 in the diagnosis of OA was 90% and the specificity was 78%. CTX-II and YKL-40 levels in different Kellgren Lawrence (K-L) grades were significantly different (P<0.001), and increased with the increase of K-L grade. Concentrations of serum CTX-II and YKL-40 before treatment in the study group was positively correlated with WOMAC score (P<0.001). At 3, 6 and 9 weeks after the beginning of treatment, serum concentrations of CTX-II and YKL-40 decreased significantly (P<0.001). At 3 weeks of treatment, CTX-II was positively correlated with YKL-40 concentration and WOMAC score (r=0.406, P<0.001; r=0.430, P<0.001); CTX-II was positively correlated with YKL-40 concentration and WOMAC score at 6 weeks of treatment (r=0.350, P<0.001; r=0.358, P<0.001); CTX-II was positively correlated with YKL-40 concentration and WOMAC score at 9 weeks after treatment (r=0.370, P<0.001; r=0.394, P<0.001). Combined detection of serum CTX-II and YKL-40 can improve the sensitivity of early OA diagnosis, and it has an important diagnostic value for early OA patients. Therefore, it can be used as a biological indicator for early OA diagnosis, severity assessment, and evaluation of treatment effects.

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.

High glycine concentration increases collagen synthesis by articular chondrocytes in vitro: acute glycine deficiency could be an important cause of osteoarthritis

Collagen synthesis is severely diminished in osteoarthritis; thus, enhancing it may help the regeneration of cartilage. This requires large amounts of glycine, proline and lysine. Previous works of our group have shown that glycine is an essential amino acid, which must be present in the diet in large amounts to satisfy the demands for collagen synthesis. Other authors have shown that proline is conditionally essential. In this work we studied the effect of these amino acids on type II collagen synthesis. Bovine articular chondrocytes were cultured under a wide range of different concentrations of glycine, proline and lysine. Chondrocytes were characterized by type II collagen immunocytochemistry of confluence monolayer cultures. Cell growth and viability were assayed by trypan blue dye exclusion method. Type II collagen was measured in the monolayer, every 48 h for 15 days by ELISA. Increase in concentrations of proline and lysine in the culture medium enhances the synthesis of type II collagen at low concentrations, but these effects decay before 1.0 mM. Increase of glycine as of 1.0 mM exceeds these effects and this increase continues more persistently by 60–75%. Since the large effects produced by proline and lysine are within the physiological range, while the effect of glycine corresponds to a much higher range, these results demonstrated a severe glycine deficiency for collagen synthesis. Thus, increasing glycine in the diet may well be a strategy for helping cartilage regeneration by enhancing collagen synthesis, which could contribute to the treatment and prevention of osteoarthritis.

Effectiveness and safety of glucosamine and chondroitin for the treatment of osteoarthritis: a meta-analysis of randomized controlled trials

Objective

To assess the symptomatic effectiveness and safety of oral symptomatic slow-acting drugs (SYSADOAs) on the treatment of knee and/or hip osteoarthritis, such as chondroitin, glucosamine, and combination treatment with chondroitin plus glucosamine.

Methods

We searched electronic database including PubMed, Embase, Cochrane Library, and the reference lists of relevant articles published from inception to May 22, 2018. An updated meta-analysis was performed to assess the effectiveness of these slow-acting drugs for osteoarthritis.

Results

Twenty-six articles describing 30 trials met our inclusion criteria and were included in the meta-analysis. The estimates between chondroitin and placebo showed that chondroitin could alleviate pain symptoms and improve function. Compared with placebo, glucosamine proved significant effect only on stiffness improvement. However, the combination therapy did not have enough evidence to be superior to placebo. Additionally, there was no significant difference in the incidence of AEs and discontinuations of AEs when compared with placebo.

Conclusions

Given the effectiveness of these symptomatic slow-acting drugs, oral chondroitin is more effective than placebo on relieving pain and improving physical function. Glucosamine showed effect on stiffness outcome. Regarding on the limited number of combination therapy, further studies need to investigate the accurate effectiveness. This information accompanied with the tolerability and economic costs of included treatments would be conducive to making decisions for clinicians.

Electronic supplementary material

The online version of this article (10.1186/s13018-018-0871-5) contains supplementary material, which is available to authorized users.