Biological markers in osteoarthritis

sCTX II is a better biomarker than sMMP-3 to identify early knee osteoarthritis

The aim of this study is to assess the ability of serum MMP-3 and serum CTX-II levels to differentiate between normal and early knee osteoarthritis case (eKOA). Subjects with clinical features of primary knee osteoarthritis of K-L Grade I and K-L Grade II with ages more than 45 years were included in the case group (98), and healthy adults with ages less than 40 years were included in the control group (80). Those having knee pain for the last 3 months but having no radiological features were labeled as K-L grade I and those having minimal osteophytes on radiographs were labeled as K-L Grade II. Antero-posterior views of knee and serum levels of MMP-3 and CTX II were estimated. Cases show significantly higher values of both biomarkers than in controls (p < 0.0001). Both biomarkers show significantly higher values with an increase in K-L Grades, that is, K-L Grade 0 versus I (MMP-3: p = 0.003; CTX-II: p = 0.002), K-L Grade I versus II (MMP-3: p < 0.000; CTX-II: p < 0.000). Multivariate analysis shows the dependence of both biomarkers only on K-L Grades. ROC analysis suggests cutoff value between KL Grade 0 and Grade I (MMP-3: 12.25 ng/mL; CTX II: 407.50 pg/mL) and between K L Grade I and Grade II (MMP-3: 18.37 ng/mL; CTX II: 528.00 pg/mL). The discriminating ability of CTX II is superior between normal population and eKOA (CTX II: Accuracy: 66.83%, p = 0.0002; MMP-3: Accuracy: 50.39%, p = 0.138), but MMP-3 is superior than CTX II between eKOA and mild KOA (CTX II:67.52%, p < 0.000; MMP-3: 70.69%, p < 0.000).

MRI overestimates articular cartilage thickness and volume compared to synchrotron radiation phase-contrast imaging

Accurate evaluation of morphological changes in articular cartilage are necessary for early detection of osteoarthritis (OA). 3T magnetic resonance imaging (MRI) has highly sensitive contrast resolution and is widely used clinically to detect OA. However, synchrotron radiation phase-contrast imaging computed tomography (SR-PCI) can also provide contrast to tissue interfaces that do not have sufficient absorption differences, with the added benefit of very high spatial resolution. Here, MRI was compared with SR-PCI for quantitative evaluation of human articular cartilage. Medial tibial condyles were harvested from non-OA donors and from OA patients receiving knee replacement surgery. Both imaging methods revealed that average cartilage thickness and cartilage volume were significantly reduced in the OA group, compared to the non-OA group. When comparing modalities, the superior resolution of SR-PCI enabled more precise mapping of the cartilage surface relative to MRI. As a result, MRI showed significantly higher average cartilage thickness and cartilage volume, compared to SR-PCI. These data highlight the potential for high-resolution imaging of articular cartilage using SR-PCI as a solution for early OA diagnosis. Recognizing current limitations of using a synchrotron for clinical imaging, we discuss its nascent utility for preclinical models, particularly longitudinal studies of live animal models of OA.

Quantitative bone imaging biomarkers and joint space analysis of the articular Fossa in temporomandibular joint osteoarthritis using artificial intelligence models

Temporomandibular joint osteoarthritis (TMJ OA) is a disease with a multifactorial etiology, involving many pathophysiological processes, and requiring comprehensive assessments to characterize progressive cartilage degradation, subchondral bone remodeling, and chronic pain. This study aimed to integrate quantitative biomarkers of bone texture and morphometry of the articular fossa and joint space to advance the role of imaging phenotypes for diagnosis of Temporomandibular Joint Osteoarthritis (TMJ OA) in early to moderate stages by improving the performance of machine-learning algorithms to detect TMJ OA status. Ninety-two patients were prospectively enrolled (184 h-CBCT scans of the right and left mandibular condyles), divided into two groups: 46 control and 46 TMJ OA subjects. No significant difference in the articular fossa radiomic biomarkers was found between TMJ OA and control patients. The superior condyle-to-fossa distance (p < 0.05) was significantly smaller in diseased patients. The interaction effects of the articular fossa radiomic biomarkers enhanced the performance of machine-learning algorithms to detect TMJ OA status. The LightGBM model achieved an AUC 0.842 to diagnose the TMJ OA status with Headaches and Range of Mouth Opening Without Pain ranked as top features, and top interactions of VE-cadherin in Serum and Angiogenin in Saliva, TGF-β1 in Saliva and Headaches, Gender and Muscle Soreness, PA1 in Saliva and Range of Mouth Opening Without Pain, Lateral Condyle Grey Level Non-Uniformity and Lateral Fossa Short Run Emphasis, TGF-β1 in Serum and Lateral Fossa Trabeculae number, MMP3 in Serum and VEGF in Serum, Headaches and Lateral Fossa Trabecular spacing, Headaches and PA1 in Saliva, and Headaches and BDNF in Saliva. Our preliminary results indicate that condyle imaging features may be more important in regards to main effects, but the fossa imaging features may have a larger contribution in terms of interaction effects. More studies are needed to optimize and further enhance machine-learning algorithms to detect early markers of disease, improve prediction of disease progression and severity to ultimately better serve clinical decision support systems in the treatment of patients with TMJ OA.

Effect of Different Collagen on Anterior Cruciate Ligament Transection and Medial Meniscectomy-Induced Osteoarthritis Male Rats

Osteoarthritis (OA) is a common type of arthritis characterized by degeneration of the articular cartilage and joint dysfunction. Various pharmacological and non-pharmacological techniques have been used to manage these diseases. Due to the diverse therapeutic properties of marine collagen, it has received considerable attention in its pharmacological application. Thus, the purpose of this study was to compare the efficacy of jellyfish collagen, collagen peptide, other sources of marine collagen, and glycine in treating OA. In the OA rat model, an anterior cruciate ligament transection combined with medial meniscectomy surgery (ACLT + MMx) was used to induce osteoarthritis in rats. Two weeks before surgery, male Sprague–Dawley rats were fed a chow-fat diet. After 6 weeks of treatment with collagen, collagen peptide, and glycine, the results show that they could inhibit the production of proinflammatory cytokines and their derivatives, such as COX-2, MMP-13, and CTX-II levels; therefore, it can attenuate cartilage degradation. Moreover, collagen peptides can promote the synthesis of collagen type II in cartilage. These results demonstrate that collagen and glycine have been shown to have protective properties against OA cartilage degradation. In contrast, collagen peptides have been shown to show cartilage regeneration but less protective properties. Jellyfish collagen peptide at a dose of 5 mg/kg b. w. has the most significant potential for treating OA because it protects and regenerates cartilage in the knee.

Past, present, and future of cartilage restoration: from localized defect to arthritis

BACKGROUND

Osteoarthritis, one of the most common joint diseases, is characterized by the loss of joint function due to articular cartilage destruction. Herein, we review current and previous research involving the clinical applications of arthritis therapy and suggest potential therapeutic options for osteoarthritis in the future.

PAST, PRESENT, AND FUTURE TREATMENT

The arthroscopic cartilage regeneration procedure or realignment osteotomy has been performed as a joint-conserving procedure in cases where conservative treatment for damaged articular cartilage and early osteoarthritis failed. If cartilage regeneration is ineffective or if the joint damage progresses, arthroplasty is the main treatment option. The need for biological arthritis treatment has expanded as the healthy lifespan of the global population has increased. Accordingly, minimally invasive surgical treatment has been developed for the treatment of damaged cartilage and early osteoarthritis. However, patients generally prefer to avoid all types of surgery, including minimally invasive surgery. Therefore, in the future, the treatment of osteoarthritis will likely involve injection or medication.

CONCLUSION

Currently, arthritis management primarily involves the surgical application of therapeutic agents to the joints. However, nonsurgical or prophylactic methods are expected to become mainstream arthritis therapies in the future.

In vitro and in vivo Effects of a Single Dose of Bupivacaine 5% on Donkey Chondrocytes

Single intra-articular (IA) injection of long-acting local anesthetics such as bupivacaine is commonly used clinically for postoperative analgesia, in particular, after arthroscopic surgery. Despite their widespread use, the side effects of IA bupivacaine on joint cartilage as well as hepatotoxic and nephrotoxic effects remain to be elucidated. The aim of this study is to assess the in vitro effect of bupivacaine 5% on donkey chondrocytes at different time points, in addition to the in vivo effects of a single IA bupivacaine injection on the middle carpal joint in a group of 10 clinically healthy adult male donkeys. In phase I, the effect of in vitro treatment with bupivacaine 5% or saline 0.9% on freshly isolated donkey chondrocytes for 30, 60 min, 24, 48, and 96 h was investigated using MTT and LIVE/DEAD assay. In phase II, in vivo effects of single injection of bupivacaine on the middle carpal joint of the donkey were evaluated compared with saline 0.9%. Biochemical analysis of collected serum and synovia was performed. Additionally, articular cartilage damage was evaluated using radiography, computed tomography (CT), catabolic marker expression via quantitative polymerase chain reaction (qPCR), and histopathological examination 96 h after injection. Our results showed that after a 30-min exposure to bupivacaine 5%, the viability of donkey chondrocytes was 97.3 ± 4.4% and was not significantly affected at the indicated time points (n = 8, p < 0.05). No significant changes in biochemical analytes of serum and synovial fluid following IA bupivacaine injection were observed, compared with saline injection (n = 5 for each group, p < 0.05). Furthermore, in vivo IA injection of bupivacaine revealed no significant differences in radiography, CT scan, gene expression of cartilage catabolic biomarkers, and histopathological examination. These results provide an evidence for the safety of bupivacaine on the donkey cartilage.

A Preliminary Study of Combined Detection of COMP, TIMP-1, and MMP-3 in Synovial Fluid: Potential Indicators of Osteoarthritis Progression

OBJECTIVE

Osteoarthritis (OA) commonly affects weight-bearing joints and is characterized by articular cartilage breakdown combined with osteophyte formation at the joint margins and chronic nonspecific inflammation of synovium. Understanding the profile of inflammation in a patient population is an essential starting point to predict or prevent OA progression. The aim of this study was to identify the profile of selected biomolecules in synovial fluid (SF) and investigate the correlation according to gender, age, and severity of the disease within patients from among the general knee OA population.

DESIGN

In our study SF samples were aspirated from the knees of 65 OA patients (46 patients with early knee OA and 19 patients with end-stage knee OA according to the Kellgren-Lawrence grading scale). The concentration of interleukins (IL-6, IL-8), matrix metalloproteinases (MMP-1, MMP-3, MMP-13), MMPs inhibitors (TIMP-1, TIMP-2), cartilage oligomeric matrix protein (COMP), and adiponectin was analyzed using a multiplex ELISA-based approach.

CONCLUSIONS

Our results indicate significant linear correlation of MMP-13 and COMP concentration with age (P < 0.05), but not with OA severity. In fact, 3 of the examined biomolecules, MMP-3 (P < 0.01), TIMP-1 (P < 0.01), and COMP (P < 0.05) significantly correlate with the grade of knee OA and might be associated with OA severity.

MiR-485-3p promotes proliferation of osteoarthritis chondrocytes and inhibits apoptosis via Notch2 and the NF-κB pathway

CONTEXT

Osteoarthritis (OA) is one of the leading causes of disability worldwide. microRNAs (miRs) has been shown to be involved in multiple pathological processes during OA. But the possible mechanism of miR-485-3p in OA remains unclear.

OBJECTIVE

This study was designed to identify the effect of miR-485-3p on OA.

METHODS

miR-485-3p expression in the cartilage of OA patients and healthy controls was detected. OA cell model was established by lipopolysaccharide (LPS). miR-485-3p expression in SW1353 and CHON-001 chondrocytes treated with LPS was detected. After overexpressing miR-485-3p in chondrocytes, cell proliferation, and apoptosis were detected. Apoptosis-, extracellular matrix (ECM)-, inflammatory-, and oxidative stress-related factors were detected. The target gene of miR-485-3p was predicted by online software and verified by dual luciferase reporter gene assay. Notch2 was intervened in CHON-001 chondrocytes to detect proliferation and apoptosis. Finally, the phosphorylation of NF-κB pathway-related proteins was detected.

RESULTS

miR-485-3p expression was low in OA patients and LPS-treated chondrocytes. After LPS treatment, the proliferation of SW1353 and CHON-001 chondrocytes was decreased, and apoptosis was increased. The above outcomes were reversed after overexpressing miR-485-3p. Overexpressing miR-485-3p also reduced ECM degradation, inflammation and oxidative stress in chondrocytes. miR-485-3p could target Notch2. After LPS treatment, the NF-κB pathway was activated, but miR-485-3p overexpression inhibited the pathway. Notch2 inhibition promoted proliferation and inhibited apoptosis of LPS-treated CHON-001 chondrocytes, and inhibited the NF-κB pathway.

CONCLUSION

Overexpression of miR-485-3p inhibited Notch2 and the NF-κB pathway, and promoted proliferation of OA chondrocytes and inhibited apoptosis.

Chondroprotection and Molecular Mechanism of Action of Phytonutraceuticals on Osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease and an important cause of incapacitation. There is a lack of drugs and effective treatments that stop or slow the OA progression. Modern pharmacological treatments, such as analgesics, have analgesic effects but do not affect the course of OA. Long-term use of these drugs can lead to serious side effects. Given the OA nature, it is likely that lifelong treatment will be required to stop or slow its progression. Therefore, there is an urgent need for disease-modifying OA treatments that are also safe for clinical use over long periods. Phytonutraceuticals are herbal products that provide a therapeutic effect, including disease prevention, which not only have favorable safety characteristics but may have an alleviating effect on the OA and its symptoms. An estimated 47% of OA patients use alternative drugs, including phytonutraceuticals. The review studies the efficacy and action mechanism of widely used phytonutraceuticals, analyzes the available experimental and clinical data on the effect of some phytonutraceuticals (phytoflavonoids, polyphenols, and bioflavonoids) on OA, and examines the known molecular effect and the possibility of their use for chondroprotection.

Recent developments in natural and synthetic polymeric drug delivery systems used for the treatment of osteoarthritis

Osteoarthritis (OA), is a common musculoskeletal disorder that will progressively increase in older populations and is expected to be the most dominant cause of disability in the world population by 2030. The progression of OA is controlled by a multi-factorial pathway that has not been completely elucidated and understood yet. However, over the years, research efforts have provided a significant understanding of some of the processes contributing to the progression of OA. Both cartilage and bone degradation processes induce articular cells to produce inflammatory mediators that produce proinflammatory cytokines that block the synthesis of collagen type II and aggrecan, the major components of cartilage. Systemic administration and intraarticular injection of anti-inflammatory agents are the first-line treatments of OA. However, small anti-inflammatory molecules are rapidly cleared from the joint cavity which limits their therapeutic efficacy. To palliate this strong technological drawback, different types of polymeric materials such as microparticles, nanoparticles, and hydrogels, have been examined as drug carriers for the delivery of therapeutic agents to articular joints. The main purpose of this review is to provide a summary of recent developments in natural and synthetic polymeric drug delivery systems for the delivery of anti-inflammatory agents to arthritic joints. Furthermore, this review provides an overview of the design rules that have been proposed so far for the development of drug carriers used in OA therapy. Overall it is difficult to state clearly which polymeric platform is the most efficient one because many advantages and disadvantages could be pointed to both natural and synthetic formulations. That requires further research in the near future.

Genetic markers of osteoarthritis: early diagnosis in susceptible Pakistani population

Background and aim

Osteoarthritis (OA) is a multiple factorial disease with unidentified specific markers. The alternate method such as biochemical and genetic markers for the diagnosis of osteoarthritis is an undeniable need of the current era. In the present study, we aimed to investigate the association of interleukin-6 (IL-6)(IL-6-174G/C), transforming growth factor-β1 (TGF-beta1-29C/T), and calmodulin 1 gene-16C/T (CALM1-16C/T) polymorphism in clinically definite Pakistani OA patients and matching controls.

Methods

The study design was based on biochemical analysis of OA via serum hyaluronic acid (HA) enzyme-linked immunosorbent assay (ELISA) test and genetic analysis based on amplification refractory mutation system (ARMS) PCR. Statistical evaluations of allele probabilities were carried through chi-squared test. This study includes 295 subjects including 100 OA patients, 105 OA susceptible, and 90 controls.

Results

HA levels obtained were distinct for all the populations: patients with a mean value of ± 5.15, susceptible with mean value of ± 2.27, and control with mean value of ± 0.50. The prevalent genotypes in OA were GG genotype for IL-6-174G/C, CT genotypes for TGF β1-29C/T, and TT genotype for CALM1-16C/T polymorphism. A significant P value of 0.0152 is obtained as a result of the comparison among the patients and controls on the number of individuals possessing the disease-associated genotypes.

Conclusions

The positive association of GG genotype for IL-6-174G/C, TT genotype for CALM1-16C/T polymorphism in OA while high prevalence of CT TGF β1-29 C/T genotypes in susceptible population in our study group implies these polymorphisms can serve as susceptible marker to OA and genetic factors for screening OA patients in Pakistan. There might be other factors that may influence disease susceptibility. However, further investigations on larger population are required to determine the consequences of genetic variations for prediagnosis of OA.

Highly specific recognition of denatured collagen by fluorescent peptide probes with the repetitive Gly-Pro-Pro and Gly-Hyp-Hyp sequences

Denatured collagen is a key biomarker for various critical diseases such as cancer. Peptide probes with the repetitive (Gly-Pro-Hyp)n sequences have recently been found to selectively target denatured collagen; however, thermal or UV pretreatment is required to drive the peptides into the monomer conformation, which poses a substantial challenge for clinical applications. We herein construct two peptide probes, FAM-GOO and FAM-GPP, consisting of the repetitive (Gly-Hyp-Hyp)8 and (Gly-Pro-Pro)8 sequences, respectively. The CD, fluorescence and colorimetric studies have consistently revealed that FAM-GOO showed strong capability of forming the triple helical structure, while FAM-GPP pronouncedly displayed the single stranded conformation at temperatures as low as 4 °C. The binding experiments have indicated that both peptide probes could recognize denatured collagen with high specificity, and FAM-GPP remarkably did not need the preheating treatment. The tissue staining results have shown that preheated FAM-GOO and unheated FAM-GPP could target denatured collagen in a wide variety of rat frozen and human FFPE tissue sections. Compared with antibodies specific for a certain type of collagen, both FAM-GOO and FAM-GPP act as broad-spectrum probes for the selective detection of denatured collagen of different types and from different species. Importantly, FAM-GPP possessed the unique capability of maintaining the monomer conformation by itself, thus avoiding the potential risks of the thermal or UV pretreatment. This novel peptide probe provides a handy and versatile biosensor for specifically targeting denatured collagen, which has attractive potential in the diagnosis and therapeutics of collagen-involved diseases.

Locomotion replacement exercise cannot counteract cartilage biomarker response to 5 days of immobilization in healthy adults

Biomarkers of cartilage metabolism are sensitive to changes in the biological and mechanical environment and can indicate early changes in cartilage homeostasis. The purpose of this study was to determine if a daily locomotion replacement program can serve as a countermeasure for changes in cartilage biomarker serum concentration caused by immobilization. Ten healthy male subjects (mean ± 1 standard deviation; age: 29.4 ± 5.9 years; body mass: 77.7 ± 4.1 kg) participated in the crossover 5-day bed rest study with three interventions: control (CON), standing (STA), and locomotion replacement training (LRT). Serum samples were taken before, during, and after bed rest. Biomarker concentrations were measured using commercial enzyme-linked immunosorbent assays. Cartilage oligomeric matrix protein (COMP) levels after 24 hours of bed rest decreased independently of the intervention (-16.8% to -9.8%) and continued to decrease until 72 hours of bed rest (minimum, -23.2% to -20.6%). LRT and STA did not affect COMP during bed rests (P = .056) but there was a strong tendency for a slower decrease with LRT (-9.4%) and STA (-11.7%) compared with CON (-16.8%). MMP-3 levels decreased within the first 24 hours of bed rest (CON: -22.3%; STA: -14.7%; LRT: -17%) without intervention effect. Both COMP and MMP-3 levels recovered to baseline levels during the 6-day recovery period. MMP-1, MMP-9, and TNF-α levels were not affected by immobilization or intervention. COMP and MMP-3 are mechano-sensitive cartilage biomarkers affected by immobilization, and simple interventions such as standing upright or LRT during bed rest cannot prevent these changes. Clinical significance: simple locomotion interventions cannot prevent cartilage biomarker change during bed rest.

MMP-13 enzyme and pH responsive theranostic nanoplatform for osteoarthritis

Stimulus-responsive therapy permits precise control of therapeutic effect only at lesion of interest, which determines it a promising method for diagnosis and imaging-guided precision therapy. The acid environment and overexpressed matrix metalloproteinases-13 (MMP-13) are typical markers in osteoarthritis (OA), which enables the development of stimulus-responsive drug delivery system with high specificity for OA. We herein demonstrate a nano-micelle based stimuli-responsive theranostic strategy with reporting and drug release controlled by acidic pH and MMP-13 for OA therapy. Such nanoplatform is incorporated with a motif specifically targeting on cartilage, a motif responsive to matrix metalloproteinases-13 to specifically report OA condition and biodynamics of nano-micelles, an anti-inflammatory drug (e.g., psoralidin (PSO)) from traditional Chinese medicine, and a biocompatible polymeric skeleton for sustainable drug release in response to the acidic OA condition. The high effectiveness of this targeted precision therapy is demonstrated comprehensively by both in vitro and vivo evidences.

The relationship between urinary C-Telopeptide fragments of type II collagen, knee joint load, pain, and physical function in individuals with medial knee osteoarthritis

OBJECTIVE

Considering the osteoarthritis (OA) model that integrates the biological, mechanical, and structural components of the disease, the present study aimed to investigate the association between urinary C-Telopeptide fragments of type II collagen (uCTX-II), knee joint moments, pain, and physical function in individuals with medial knee OA.

METHODS

Twenty-five subjects radiographically diagnosed with knee OA were recruited. Participants were evaluated through three-dimensional gait analysis, uCTX-II level, the WOMAC pain and physical function scores, and the 40m walk test. The association between these variables was investigated using Pearson's product-moment correlation, followed by a hierarchical linear regression, controlled by OA severity and body mass index (BMI).

RESULTS

No relationship was found between uCTX-II level and knee moments. A significant correlation between uCTX-II level and pain, physical function, and the 40m walk test was found. The hierarchical linear regression controlling for OA severity and BMI showed that uCTX-II level explained 9% of the WOMAC pain score, 27% of the WOMAC physical function score, and 7% of the 40m walk test.

CONCLUSION

Greater uCTX-II level is associated with higher pain and reduced physical function and 40m walk test performance in individuals with medial knee OA.

Intra-articular treatment options for knee osteoarthritis

Intra-articular drug delivery has a number of advantages over systemic administration; however, for the past 20 years, intra-articular treatment options for the management of knee osteoarthritis (OA) have been limited to analgesics, glucocorticoids, hyaluronic acid (HA) and a small number of unproven alternative therapies. Although HA and glucocorticoids can provide clinically meaningful benefits to an appreciable number of patients, emerging evidence indicates that the apparent effectiveness of these treatments is largely a result of other factors, including the placebo effect. Biologic drugs that target inflammatory processes are used to manage rheumatoid arthritis, but have not translated well into use in OA. A lack of high-level evidence and methodological limitations hinder our understanding of so-called 'stem' cell therapies and, although the off-label administration of intra-articular cell therapies (such as platelet-rich plasma and bone marrow aspirate concentrate) is common, high-quality clinical data are needed before these treatments can be recommended. A number of promising intra-articular treatments are currently in clinical development in the United States, including small-molecule and biologic therapies, devices and gene therapies. Although the prospect of new, non-surgical treatments for OA is exciting, the benefits of new treatments must be carefully weighed against their costs and potential risks.

Mitochondrial Genetics and Epigenetics in Osteoarthritis

During recent years, the significant influence of mitochondria on osteoarthritis (OA), the most common joint disease, has been consistently demonstrated. Not only mitochondrial dysfunction but also mitochondrial genetic polymorphisms, specifically the mitochondrial DNA haplogroups, have been shown to have an important influence on different OA-related features, including the prevalence, severity, incidence, and progression of the disease. This influence could probably be mediated by the role of mitochondria in the regulation of different processes involved in the pathogenesis of OA, such as energy production, the generation of reactive oxygen and nitrogen species, apoptosis, and inflammation. The regulation of these processes is at least partially controlled by the bi-directional communication between the nucleus and mitochondria, which permits the regulation of adaptation to a wide range of stressors and the maintenance of cellular homeostasis. This bi-directional communication consists of an “anterograde regulation” by which the nucleus regulates mitochondrial biogenesis and activity and a “retrograde regulation” by which both mitochondria and mitochondrial genetic variation exert a regulatory signaling control over the nuclear epigenome, which leads to the modulation of nuclear genes. Throughout this mini review, we will describe the evidence that demonstrates the profound influence of the mitochondrial genetic background in the pathogenesis of OA, as well as its influence on the nuclear DNA methylome of the only cell type present in the articular cartilage, the chondrocyte. This evidence leads to serious consideration of the mitochondrion as an important therapeutic target in OA.

Protocatechuic acid attenuates anterior cruciate ligament transection-induced osteoarthritis by suppressing osteoclastogenesis

Osteoarthritis (OA) is related to over-proliferation or differentiation of osteoclasts. Although protocatechuic acid (PCA) has been identified to inhibit osteoclast differentiation and stimulate apoptosis in mature osteoclasts, whether it can relieve OA is still unknown. The present study aimed to investigate the effect of PCA on anterior cruciate ligament transection (ACLT)-induced OA and the potential mechanisms of action behind this effect. ACLT was performed on rats, which were then treated with or without PCA. C-terminal telopeptide of type I collagen (CTX-I) and CTX-II were tested in knee joint protein extracts by ELISA. Damage to cartilage was evaluated using Safranin-O/Fast Green staining. Osteoclast-related gene and protein expression was assessed through reverse transcription-quantitative PCR and western blotting. Tartrate-resistant acid phosphatase (TRAP) staining and functional bone resorption pit assays were performed using RAW264.7 murine macrophage cells to determine the effects of PCA on osteoclastic formation and function, respectively, in vitro. Finally, the activity of osteoclastogenesis-related signaling pathways was evaluated by western blotting. Levels of CTX-II were relatively decreased and Safranin-O/fast green staining indicated milder changes in the articular cartilage in the PCA treatment group. PCA downregulated osteoclast specific markers and suppressed receptor activator of nuclear factor-κB ligand-induced formation of TRAP-positive multinucleated cells, bone-resorption and pit formation. Mitogen-activated protein kinase (MAPK) and Akt signaling as well as the downstream factors, were downregulated by PCA. In conclusion, the present study demonstrated that PCA attenuated ACLT-induced OA by suppressing osteoclastogenesis by inhibiting the MAPK, ATK and NF-κB signaling pathways.

Membrane-Free Stem Cell Components Inhibit Interleukin-1α-Stimulated Inflammation and Cartilage Degradation in vitro and in vivo: A Rat Model of Osteoarthritis

Membrane-free stem cell components (MFSCC) from basal adipose tissue-derived stem cells (ADSCs) are unknown for the treatment strategies in osteoarthritis (OA). OA has been considered to be associated with inflammatory damage and cartilage degradation. In this study, we intended to investigate the molecular mechanism of the anti-inflammation and cartilage protection effect of MFSCC in vitro (rat primary chondrocytes) and in vivo (rat OA model). The MFSCC treatment significantly inhibited interleukin-1α (IL-1α) stimulated inflammation and cartilage degradation. The MFSCC considerably reduced the levels of inflammatory factors such as iNOS, COX-2, NO, and PGE₂ and was suppressed NF-κB and MAPKs signaling pathways in IL-1α-stimulated rat chondrocytes. Additionally, biomarkers of OA such as MMP-9, COMP, and CTX-II decreased in the monosodium iodoacetate (MIA)-induced rat OA model by MFSCC treatment. In conclusion, the MFSCC was established to suppress IL-1α induced inflammation and cartilage degradation in vitro and in vivo. These findings provide new insight for understanding OA therapy using membrane-free stem cell approaches.

Cartilage-targeting and dual MMP-13/pH responsive theranostic nanoprobes for osteoarthritis imaging and precision therapy

Osteoarthritis (OA) microenvironment is marked by matrix metalloproteinases-13 (MMP-13) overexpression and weak acidity, making it possible to develop dual-stimuli responsive theranostic nanoprobes for OA diagnosis and therapy. However, current MMP/pH-responsive systems are not suitable for OA because of their poor biocompatibility, poor degradation and non-cartilage-targeting of the responsive probes. Here we designed a novel biocompatible cartilage-targeting and MMP-13/pH-responsive ferritin nanocages (CMFn) loaded with an anti-inflammatory drug (Hydroxychloroquine, HCQ), termed CMFn@HCQ, for OA imaging and therapy. We found that CMFn could be smartly "turned on" to emit light for OA imaging in response to the level of overexpressed MMP-13 in OA microenvironment, corresponding to the degree of OA severity. Thus the light intensity detected reflected the degree of OA severity, enabling the precise disease classification by our CMFn. CMFn could be "turned off" to stop emitting light in the normal joint. CMFn@HCQ nanocages could target the cartilage and release HCQ in the OA joint specifically under acidic pH conditions in a sustained manner, prolonging the drug retention time to 14 days to remarkably reduce synovial inflammation in the OA joints. The CMFn@HCQ nanocages represent a smart dual-stimuli responsive and cartilage-targeting nanoprobes, and hold promise for imaging-guided precision therapy for OA.

Minimally Invasive Approach for Diagnosing TMJ Osteoarthritis

This study's objectives were to test correlations among groups of biomarkers that are associated with condylar morphology and to apply artificial intelligence to test shape analysis features in a neural network (NN) to stage condylar morphology in temporomandibular joint osteoarthritis (TMJOA). Seventeen TMJOA patients (39.9 ± 11.7 y) experiencing signs and symptoms of the disease for less than 10 y and 17 age- and sex-matched control subjects (39.4 ± 15.2 y) completed a questionnaire, had a temporomandibular joint clinical exam, had blood and saliva samples drawn, and had high-resolution cone beam computed tomography scans taken. Serum and salivary levels of 17 inflammatory biomarkers were quantified using protein microarrays. A NN was trained with 259 other condyles to detect and classify the stage of TMJOA and then compared to repeated clinical experts' classifications. Levels of the salivary biomarkers MMP-3, VE-cadherin, 6Ckine, and PAI-1 were correlated to each other in TMJOA patients and were significantly correlated with condylar morphological variability on the posterior surface of the condyle. In serum, VE-cadherin and VEGF were correlated with one another and with significant morphological variability on the anterior surface of the condyle, while MMP-3 and CXCL16 presented statistically significant associations with variability on the anterior surface, lateral pole, and superior-posterior surface of the condyle. The range of mouth opening variables were the clinical markers with the most significant associations with morphological variability at the medial and lateral condylar poles. The repeated clinician consensus classification had 97.8% agreement on degree of degeneration within 1 group difference. Predictive analytics of the NN's staging of TMJOA compared to the repeated clinicians' consensus revealed 73.5% and 91.2% accuracy. This study demonstrated significant correlations among variations in protein expression levels, clinical symptoms, and condylar surface morphology. The results suggest that 3-dimensional variability in TMJOA condylar morphology can be comprehensively phenotyped by the NN.

Association of UCMA levels in serum and synovial fluid with severity of knee osteoarthritis

AIM

Osteoarthritis (OA) is one of the most common joint diseases causing physical disability in the aged population. OA pathogenesis is not fully known and yet there are no effective therapeutic options against OA. Upper Zone of Growth Plate and Cartilage Matrix Associated (UCMA) is a member of vitamin K-dependent protein family, and is involved in inflammation, cardiovascular diseases, cancer, and OA. In the present study, our aim was to detect serum and synovial fluid (SF) levels of UCMA and to analyze their correlation with radiographic findings and symptomatic severity in OA patients as well as the correlation between oxidative stress levels and SF UCMA levels.

METHODS

Forty OA patients with cartilage degeneration and 20 patients with other knee joint disorders (non-OA control) were included in the present study. We used the Kellgren-Lawrence (KL) classification and Western Ontario McMaster University Osteoarthritis Index (WOMAC) scores to assess radiographic grading and symptomatic severity of OA, respectively. UCMA levels were measured in SF and serum. And also oxidative stress markers were analyzed in SF.

RESULTS

SF UCMA levels of OA patients were higher compared to those of the non-OA control group and were positively correlated with radiographic finding and symptomatic severity of OA. However, there was no significant correlation between oxidative markers of SF and the KL grade, WOMAC scores, and SF UCMA levels in OA patients.

CONCLUSION

There is a close connection between UCMA SF levels and symptomatic and radiographic severities of knee OA. Therefore, UCMA can be a promising biomarker in the diagnosis and/or prognosis of OA disease.

Diagnostic value of the blood monocyte-lymphocyte ratio in knee osteoarthritis

Objective

Knee osteoarthritis (KOA) is a chronic inflammatory disease. The monocyte–lymphocyte ratio (MLR) was reported to be a non-invasive, cost-effective marker in various systemic diseases, but it has not yet been investigated in KOA. This cross-sectional study evaluated the diagnostic value of MLR in KOA.

Methods

Two hundred and five KOA patients and 120 healthy control subjects were enrolled. Patient data, including age, sex, blood cell counts, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) levels, red blood cell distribution width, and the Kellgren–Lawrence (KL) score were recorded.

Results

One hundred nineteen patients (55 men, 64 women) were included, with a mean age of 55.47 ± 9.23 years. KOA patients showed a significantly higher MLR, neutrophil–lymphocyte ratio (NLR), and platelet–lymphocyte ratio (PLR) than controls. The MLR area under the curve was 0.81, which was higher than that of NLR and PLR. Multiple logistic regression analysis revealed blood MLR as an independent predictor of KOA. Correlation analysis showed that MLR was positively correlated with ESR and CRP levels. MLR and NLR were significantly higher in KL4 patients than in KL1–3 patients.

Conclusions

MLR has a high diagnostic value for KOA, so could be a reliable disease marker.

Association between changes in molecular biomarkers of cartilage matrix turnover and changes in knee articular cartilage: a longitudinal pilot study

Background

An early detection of Osteoarthritis is urgently needed and still not possible until today. The aim of the study was to assess whether molecular biomarkers of cartilage turnover are associated with longitudinal change in knee cartilage thickness during a 2 year period in individuals with increased risk of developing knee osteoarthritis. A secondary aim was to assess whether prior knee injury or subjective patient-reported outcomes at baseline (BL) were associated with articular cartilage changes. Nineteen volleyball players (mean age 46.5 ± 4.9 years, 47% male) with a 30-year history of regular high impact training were recruited. The serum biomarkers Cpropeptide of type II procollagen (CPII), cartilage oligomeric matrix protein (COMP), collagenase generated carboxy-terminal neoepitope of type II collagen (sC2C), cartilage intermediate layer protein 2 (CILP-2), and the urine biomarkers C-telopeptide of type II collagen (CTX-II) and collagenase-generated peptide(s) of type II collagen (C2C-HUSA) were assessed at BL and at 2 year follow up (FU). Femorotibial cartilage thinning, thickening and absolute thickness change between BL and FU was evaluated from magnetic resonance imaging. Subjective clinical status at BL was evaluated by the International Knee Documentation Committee Subjective Knee Form and the Short-Form 36 Physical Component Score.

Results

CILP-2 was significantly higher at FU and linearly associated with the absolute cartilage thickness change during the experimental period. Prior injury was a predictor of increased absolute cartilage thickness change.

Conclusion

Measuring the change in the cartilage biomarker CILP-2 might be a valid and sensitive method to detect early development of knee osteoarthritis as CILP-2 appears to be related to cartilage thickness loss in certain individuals with increased risk of developing knee osteoarthritis. Prior knee injury may be predictive of increased articular cartilage thickness change.

Adverse Effects of Fine-Particle Exposure on Joints and Their Surrounding Cells and Microenvironment

Current understanding of the health risks and adverse effects upon exposure to fine particles is premised on the direct association of particles with target organs, particularly the lung; however, fine-particle exposure has also been found to have detrimental effects on sealed cavities distant to the portal-of-entry, such as joints. Moreover, the fundamental toxicological issues have been ascribed to the direct toxic mechanisms, in particular, oxidative stress and proinflammatory responses, without exploring the indirect mechanisms, such as compensated, adaptive, and secondary effects. In this Review, we recapitulate the current findings regarding the detrimental effects of fine-particle exposure on joints, the surrounding cells, and microenvironment, as well as their deteriorating impact on the progression of arthritis. We also elaborate the likely molecular mechanisms underlying the particle-induced detrimental influence on joints, not limited to direct toxicity, but also considering the other indirect mechanisms. Because of the similarities between fine air particles and engineered nanomaterials, we compare the toxicities of engineered nanomaterials to those of fine air particles. Arthritis and joint injuries are prevalent, particularly in the elderly population. Considering the severity of global exposure to fine particles and limited studies assessing the detrimental effects of fine-particle exposure on joints and arthritis, this Review aims to appeal to a broad interest and to promote more research efforts in this field.

Association of Human FOS Promoter Variants with the Occurrence of Knee-Osteoarthritis in a Case Control Association Study

Our aim was to analyse (i) the presence of single nucleotide polymorphisms (SNPs) in the JUN and FOS core promoters in patients with rheumatoid arthritis (RA), knee-osteoarthritis (OA), and normal controls (NC); (ii) their functional influence on JUN/FOS transcription levels; and (iii) their associations with the occurrence of RA or knee-OA. JUN and FOS promoter SNPs were identified in an initial screening population using the Non-Isotopic RNase Cleavage Assay (NIRCA); their functional influence was analysed using reporter gene assays. Genotyping was done in RA (n = 298), knee-OA (n = 277), and NC (n = 484) samples. For replication, significant associations were validated in a Finnish cohort (OA: n = 72, NC: n = 548). Initially, two SNPs were detected in the JUN promoter and two additional SNPs in the FOS promoter in perfect linkage disequilibrium (LD). JUN promoter SNP rs4647009 caused significant downregulation of reporter gene expression, whereas reporter gene expression was significantly upregulated in the presence of the FOS promoter SNPs. The homozygous genotype of FOS promoter SNPs showed an association with the susceptibility for knee-OA (odds ratio (OR) 2.12, 95% confidence interval (CI) 1.2–3.7, p = 0.0086). This association was successfully replicated in the Finnish Health 2000 study cohort (allelic OR 1.72, 95% CI 1.2–2.5, p = 0.006). FOS Promoter variants may represent relevant susceptibility markers for knee-OA.

Novel model for the induction of postnatal murine hip deformity

Acetabular dysplasia is a common, multi-etiological, pre-osteoarthritic (OA) feature that can lead to pain and instability of the young adult hip. Despite the clinical significance of acetabular dysplasia, there is a paucity of small animal models to investigate structural and functional changes that mediate morphology of the dysplastic hip and drive the subsequent OA cascade. Utilizing a novel murine model developed in our laboratory, this study investigated the role of surgically induced unilateral instability of the postnatal hip on the initiation and progression of acetabular dysplasia and impingement up to 8-weeks post-injury. C57BL6 mice were used to develop titrated levels of hip instability (i.e., mild, moderate, and severe instabillity or femoral head resection) at weaning. Joint shape, acetabular coverage, histomorphology, and statistical shape modeling were used to assess quality of the hip following 8 weeks of destabilization. Acetabular coverage was reduced following severe, but not moderate, instability. Moderate instability induced lateralization of the femur without dislocation, whereas severe instability led to complete dislocation and pseudoacetabulae formation. Mild instability did not result in morphological changes to the hip. Removal of the femoral head led to reduced hip joint space volume. These data support the notion that hip instability, driven by mechanical loss-of-function of soft connective tissue, can induce morphometric changes in the growing mouse hip. This work developed a new mouse model to study hip health in the murine adolescent hip and is a useful tool for investigating the mechanical and structural adaptations to hip instability during growth. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Correlation of serum cartilage oligomeric matrix protein with knee osteoarthritis diagnosis: a meta-analysis

BACKGROUND

The measurement of cartilage oligomeric matrix protein (COMP) has become a novel way for the diagnosis of knee osteoarthritis (OA). However, no conclusive correlation has been drawn between COMP and knee OA. The purpose of this study was to examine the utility of serum COMP as biomarker for knee OA and its relation with disease severity.

METHODS

A systematic search on PubMed, ScienceDirect, and EMBASE was conducted in January 2018 using certain keywords. Initial search yielded a total of 285 publications, and 35 articles were reviewed in full-text. Eventually, nine studies were included in the analysis. All the retrieved studies used Kellgren-Lawrence (K-L) classification for knee OA and provided available data of serum COMP in OA patients and healthy controls. Sensitivity analysis was performed by removing one study result at a time to detect the impact of each study have on the overall effect and to test the stability of the cumulative result. Subgroup study based on K-L grade system was also conducted to disclose the correlation between serum COMP and knee OA disease severity.

RESULTS

Pooled analysis of nine studies demonstrated a significant elevation of serum COMP in knee OA patients (SMD 0.81, [95% CI, 0.36, 1.25], P = 0.0004) compared with controls. In comparisons between K-L 1-4 and controls, significantly higher serum COMP was detected in all three subgroups except K-L grade 1 versus control. Comparisons among K-L grades 1-4 revealed significantly higher serum COMP levels in patients with more serious than less serious disease stage. However, the elevation in patients with K-L grade 3 did not reach statistical significance when compared with K-L grade 1 patients.

CONCLUSION

The overall analysis showed significantly higher serum COMP in knee OA patients compared to controls which indicate the potential ability of serum COMP in differentiating knee OA patients from healthy subjects. Pooled statistic of our meta-analysis showed that serum COMP levels were effective in distinguishing patients with K-L ≥ 2.

Sedentary Behavior in Patients With Knee Osteoarthritis Before and After Total Knee Arthroplasty: A Systematic Review

Objective:The objective of this systematic review is to integrate the available evidence on changes in sedentary behavior (SB) in patients with knee osteoarthritis after total knee arthroplasty (TKA).Methods:A systematic literature search from January 2002 to October 31, 2017, was performed for studies assessing objectively and/or subjectively measured SB following TKA. The Scottish Intercollegiate Guidelines Network Methodology appraisal tool was used to critically appraise the methodological quality of the included studies.Results:Ten studies reporting on SB with a total of 1,028 participants were included in the review. Three studies reported changes in SB with two showing a reduction in SB and one (with high risk of bias) an increase in SB after TKA. Seven studies showed no change in SB following TKA.Conclusion:Currently, there is insufficient evidence which suggests that SB time improves following TKA. Detailed assessments of SB after TKA are needed.

Frontline Science: Reprogramming COX-2, 5-LOX, and CYP4A-mediated arachidonic acid metabolism in macrophages by salidroside alleviates gouty arthritis

Cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LOX), and cytochrome P450 (CYP) 4A-mediated arachidonic acid (AA) metabolism play an essential role in human inflammatory disorders. Blocking COX-2 pathway would shunt AA metabolism to the other pathway, thereby decreasing the efficacy and exacerbating adverse effects. Here we demonstrated that reprogramming COX-2, 5-LOX, and CYP4A-mediated AA metabolism in macrophages by salidroside (Sal) ameliorates monosodium urate (MSU) crystal-induced inflammation. Compared with COX-2 inhibitor celecoxib, Sal (80 mg/kg) presented a superior anti-arthritic profile in MSU crystal-treated rats, accompanied with the decreased expression of COX-2, 5-LOX, and CYP4A and production of prostaglandin E2 (PGE₂ ), leukotriene B4 (LTB₄ ), and 20-hydroxyeicosatetraenoic acid (20-HETE) in the synovial fluid macrophages. Sal decreased representative M1 marker (iNOS and CD86, etc.) expression and M1 cytokine (TNF-α and IL-1β) production, whereas it increased M2 marker (CD206 and Arg-1) expression and M2 cytokine (TGF-β and IL-10) production. The injection of conditioned medium from MSU crystal-treated macrophages into the ankle joint of rats reproduced the gouty inflammation, which was attenuated by Sal. Mechanistically, down-regulation of COX-2, 5-LOX, and CYP4A in the RAW264.7 and NR8383 macrophages by Sal skewed macrophage polarization away from the M1 phenotype, and thereby prevented neutrophil migration and chondrocyte degradation with STAT1 and NF-κB inactivation. Conversely, overexpression of COX-2, 5-LOX, CYP4A or STAT1, or exogenous addition of IL-1β or TNF-α partially abolished these effects. Together, inhibition of COX-2, 5-LOX, and CYP4A in macrophages by Sal ameliorates MSU crystal-induced inflammation through decreasing TNF-α and IL-1β production, and may serve as a novel therapeutic strategy.

Identification of differentially expressed genes in synovial tissue of rheumatoid arthritis and osteoarthritis in patients

Rheumatoid arthritis (RA) and osteoarthritis (OA) are the common joints disorder in the world. Although they have showed the analogous clinical manifestation and overlapping cellular and molecular foundation, the pathogenesis of RA and OA were different. The pathophysiologic mechanisms of arthritis in RA and OA have not been investigated thoroughly. Thus, the aim of study is to identify the potential crucial genes and pathways associated with RA and OA and further analyze the molecular mechanisms implicated in genesis. First, we compared gene expression profiles in synovial tissue between RA and OA from the National Center of Biotechnology Information (NCBI) Gene Expression Omnibus (GEO) database. Gene Expression Series (GSE) 1919, GSE55235, and GSE36700 were downloaded from the GEO database, including 20 patients of OA and 21 patients of RA. Differentially expressed genes (DEGs) including "CXCL13," "CD247," "CCL5," "GZMB," "IGKC," "IL7R," "UBD///GABBR1," "ADAMDEC1," "BTC," "AIM2," "SHANK2," "CCL18," "LAMP3," "CR1," and "IL32." Second, Gene Ontology analyses revealed that DEGs were significantly enriched in integral component of extracellular space, extracellular region, and plasma membrane in the molecular function group. Signaling pathway analyses indicated that DEGs had common pathways in chemokine signaling pathway, cytokine-cytokine receptor interaction, and cytosolic DNA-sensing pathway. Third, DEGs showed the complex DEGs protein-protein interaction network with the Coexpression of 83.22%, Shared protein domains of 8.40%, Colocalization of 4.76%, Predicted of 2.87%, and Genetic interactions of 0.75%. In conclusion, the novel DEGs and pathways between RA and OA identified in this study may provide new insight into the underlying molecular mechanisms of RA.

Developing a toolkit for the assessment and monitoring of musculoskeletal ageing

The complexities and heterogeneity of the ageing process have slowed the development of consensus on appropriate biomarkers of healthy ageing. The Medical Research Council–Arthritis Research UK Centre for Integrated research into Musculoskeletal Ageing (CIMA) is a collaboration between researchers and clinicians at the Universities of Liverpool, Sheffield and Newcastle. One of CIMA’s objectives is to ‘Identify and share optimal techniques and approaches to monitor age-related changes in all musculoskeletal tissues, and to provide an integrated assessment of musculoskeletal function’—in other words to develop a toolkit for assessing musculoskeletal ageing. This toolkit is envisaged as an instrument that can be used to characterise and quantify musculoskeletal function during ‘normal’ ageing, lend itself to use in large-scale, internationally important cohorts, and provide a set of biomarker outcome measures for epidemiological and intervention studies designed to enhance healthy musculoskeletal ageing. Such potential biomarkers include: biochemical measurements in biofluids or tissue samples, in vivo measurements of body composition, imaging of structural and physical properties, and functional tests. This review assesses candidate biomarkers of musculoskeletal ageing under these four headings, details their biological bases, strengths and limitations, and makes practical recommendations for their use. In addition, we identify gaps in the evidence base and priorities for further research on biomarkers of musculoskeletal ageing.

Evaluation of the effect of the administration of a glucosamine‑containing supplement on biomarkers for cartilage metabolism in soccer players: A randomized double‑blind placebo‑controlled study

A randomized double‑blind placebo‑controlled clinical study was conducted to evaluate the chondroprotective action of glucosamine on healthy subjects (soccer players) without joint disorders. Collegiate soccer players (n=43) without joint disorders were randomly assigned to receive a glucosamine (2 g/day)‑containing supplement (n=22, glucosamine group) or a placebo (n=21, placebo group) for 16 weeks, and cartilage metabolism was evaluated by analyzing markers for type II collagen degradation urine C‑terminal telopeptide‑II (CTX‑II) and serum collagen type II cleavage (C2C) and synthesis urine C-terminal type II procollagen peptide (CPII). In the initial analysis of all subjects, urine CTX‑II level substantially decreased in the glucosamine group, but not in the placebo group after the intervention for 16 weeks (P=0.05). Moreover, CTX‑II level in the glucosamine group was also significantly lower than that in the placebo group at week 16 during the intervention. In the second analysis, to make the effect of the test supplement more clear, 41 subjects with less variation of exercise loading were evaluated. The results revealed that urine CTX‑II level significantly decreased in the glucosamine group (n=21), but not in the placebo group (n=20) after the intervention (P<0.05). Moreover, CTX‑II levels in the glucosamine group significantly decreased compared with the placebo group after the intervention (P<0.05). Both in the initial and second analyses, serum C2C level significantly decreased in the glucosamine group, but not in the placebo group after the intervention (P<0.05). In contrast, urine CPII level was not significantly changed even after the intervention in both the placebo and glucosamine groups. Importantly, no test supplement‑related adverse events were observed. These observations suggest that oral administration of glucosamine (2 g/day for 16 weeks) exerts a chondroprotective action on healthy subjects (soccer players) without joint disorders. This effect was achieved by improving cartilage metabolism (suppressing type II collagen degradation but maintaining type II collagen synthesis), without causing apparent adverse effects.

Effectiveness of Sequential Viscosupplementation in Temporomandibular Joint Internal Derangements and Symptomatology: A Case Series

Viscosupplementation is a minimally invasive technique that replaces synovial fluid by intra-articular injection of hyaluronic acid (HA). Although effective in some joints, there is not conclusive evidence regarding temporomandibular disorders. This case series described the efficacy of a viscosupplementation protocol in intra-articular temporomandibular disorders. Ten patients with a diagnosis of disc displacement and/or osteoarthritis by Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) were submitted to four monthly injections of low or medium molecular weight HA. Pain, mandibular function, image analysis by tomography and magnetic resonance, and quality of life were assessed at baseline and follow-ups (1 and 6 months). Pain, jaw range-of-motion, mandibular function, and quality of life improved at follow-up evaluations. Osteoarthritis changes decreased, and 20% of patients improved mandibular head excursion after treatment. Resolution of effusion and improvement in disc morphology were observed for most patients. This viscosupplementation protocol reduced pain and symptoms associated with internal derangement of temporomandibular joint, improved quality of life, and showed benefits from both low and medium molecular weight HA in alternate cycles.

From the lung to the knee joint: Toxicity evaluation of carbon black nanoparticles on macrophages and chondrocytes

Carbon black (CB), a core elemental carbon component of airborne particles, has been used as a model material to study environmental safety and health impacts of airborne particles. Although potential adverse effects of CB have been reported, limited knowledge is available regarding CB-induced metabolic disorders and secondary effects distant from primary target organs, such as the effects on joints. The knee cavity is a relatively closed space along the peripheral circulation route with a slow rate of interchange of nutrition with blood. While epidemiologic studies have indicated that airborne particle exposure may affect the occurrence and severity of inflammatory knee diseases, no research has been performed to understand the potential hazardous direct/indirect interactions between particles and knee cells. Herein, we have scrutinized the toxicity of four commercial nano-sized CB samples in the lung and a distant site: knee joint. Our results indicated that CB triggered pulmonary and systemic inflammation upon inhalation exposure, and, more strikingly, CB also elicited injuries of the knee joint, as demonstrated by thickened synovial membrane, suggesting disordered cellular metabolism within the knee joint. Our data recognized the CB toxicity profiles to macrophages as characterized by pro-inflammatory reactions, and also defined an activated metabolic state of chondrocytes, as evidenced by metalloproteinase (MMP) induction. Of note, remarkable variations were also found for these changes induced by these four CB samples, due to their distinct physicochemical properties. Collectively, our results uncovered a significant toxicity of CB inhalation exposure to the knee joint, as reflected by metabolic activation of chondrocytes, and, more importantly, these findings unearthed CB-induced metabolic disorders and secondary effects owing to systemic pro-inflammatory conditions upon CB exposure, in addition to the likelihood of direct toxicity to knee cells.

NLRP3 as a potentially novel biomarker for the management of osteoarthritis

Osteoarthritis (OA) was previously thought of as 'wear and tear' as humans age, however there is increasing evidence to support an inflammatory theory. The nucleotide-binding and oligomerization domain-like receptor containing protein 3 (NLRP3) inflammasome has been implicated in the pathogenesis of a number of arthritic disorders, producing proinflammatory cytokines and degradative enzymes such as Interleukin-1 beta (IL-1β), Tumour necrosis factor alpha (TNF-α) and Matrix metalloproteinase-3 (MMP-3) which drive cartilage degeneration and synovial inflammation. This review aims to summarise the evidence of NLRP3 involvement in OA. Currently, treatment options focus on management of the disease and to date there is no cure. The development of novel biomarkers for OA could improve diagnosis, treatment and management. Importantly, this review provides detail on the involvement of the NLRP3 inflammasome in OA pathology and how its members could act as potential biomarkers to assist clinical decisions.

Combating Osteoarthritis through Stem Cell Therapies by Rejuvenating Cartilage: A Review

Knee osteoarthritis (OA) is a chronic degenerative disorder which could be distinguished by erosion of articular cartilage, pain, stiffness, and crepitus. Not only aging-associated alterations but also the metabolic factors such as hyperglycemia, dyslipidemia, and obesity affect articular tissues and may initiate or exacerbate the OA. The poor self-healing ability of articular cartilage due to limited regeneration in chondrocytes further adversely affects the osteoarthritic microenvironment. Traditional and current surgical treatment procedures for OA are limited and incapable to reverse the damage of articular cartilage. To overcome these limitations, cell-based therapies are currently being employed to repair and regenerate the structure and function of articular tissues. These therapies not only depend upon source and type of stem cells but also on environmental conditions, growth factors, and chemical and mechanical stimuli. Recently, the pluripotent and various multipotent mesenchymal stem cells have been employed for OA therapy, due to their differentiation potential towards chondrogenic lineage. Additionally, the stem cells have also been supplemented with growth factors to achieve higher healing response in osteoarthritic cartilage. In this review, we summarized the current status of stem cell therapies in OA pathophysiology and also highlighted the potential areas of further research needed in regenerative medicine.

Noninvasive visualization of early osteoarthritic cartilage using targeted nanosomes in a destabilization of the medial meniscus mouse model

Background

Early stage osteoarthritis (OA) is clinically asymptomatic due to the avascular and the aneural nature of the cartilage tissue. Nevertheless, early detection of cartilage tissue is critical in order to impede the progression of OA. Hence, in order to develop effective preventive therapy for OA, diagnosis in the early stages is necessary.

Methods

To achieve this goal, we have developed targeted, fluorescent nanosomes conjugated with monoclonal anti-type II collagen antibodies (MabCII) for diagnosis of early OA. The MabCII-coated nanosomes (targeted-nanosomes) bind to the damaged cartilage explants in vitro and in vivo in an OA mouse model that mimics early stage OA. The OA mouse model was induced by destabilization of the medial meniscus (DMM) in 9–10 weeks old C57Bl/6 mice.

Results

The targeted-nanosomes enhanced the binding specificity to the cartilage tissue according to the severity of damage.

Conclusion

We show that MabCII-nanosomes can precisely detect early stage OA in the DMM mouse model. Thus, MabCII-nanosomes have the potential to be used as a non-invasive method for diagnosing the early osteoarthritic lesions.

Platelets Contribute to the Accumulation of Matrix Metalloproteinase Type 2 in Synovial Fluid in Osteoarthritis

Inflammation plays a role in the initiation and progression of osteoarthritis (OA), a chronic degenerative joint disorder. Platelets are inflammatory cells, contain and release matrix metalloproteinases (MMPs) and favour the release of these enzymes, key effectors of cartilage and subchondral bone degradation, by other cells; however, their role in OA has not been investigated yet. Our aims were (1) to assess the presence of platelets and of MMP-2 in synovial fluid (SF) of OA patients; (2) to evaluate the contribution of platelets to MMP-2 release by fibroblast-like synoviocytes (FLS); and (3) to investigate if hyaluronic acid (HA) interferes with these processes. SF was collected from 27 OA patients before and after treatment with intra-articular HA (20 mg/2 mL). Moreover, FLS were co-cultured with platelets, and the release of MMP-2 in supernatants was measured. Our results show that platelets are present in OA SF and show markers of activation. OA SF also contains relevant amounts of MMP-2. Co-incubation of platelets with FLS favours the release of MMP-2 by the interaction of platelet surface P-selectin with FLS CD44 by a mechanism involving the activation of pAkt and pSrc in FLS. Administration of HA to OA patients decreased the infiltration of platelets in SF and reduced the levels of MMP-2. The addition of HA in vitro inhibited the release of MMP-2 by FLS triggered by the interaction with platelets. In conclusion, our data show that platelets may contribute to joint degeneration in OA by favouring the accumulation of MMP-2 in SF.

Cell-type-specific gene expression patterns in the knee cartilage in an osteoarthritis rat model

Osteoarthritis (OA) is a chronic degenerative disease that leads to joint failure, pain, and disability. Gene regulation is implicated as a driver of the imbalance between the expression of catabolic and anabolic factors that eventually leads to the degeneration of osteoarthritic cartilage. In our model, knee-joint OA was induced in male Wistar rats by intra-articular sodium monoiodoacetate (MIA) injections. Whole-genome microarrays were used to analyse the alterations in gene expression during the time-course of OA development (at 2, 14, and 28 days post-injection) in rat knee joints. The identified co-expressed groups of genes were analysed for enriched regulatory mechanisms, functional classes, and cell-type-specific expression. This analysis revealed 272 regulated transcripts (ANOVA FDR < 0.1% and fold > 2). Functionally, the five major gene expression patterns (A–E) were connected to PPAR signalling and adipogenesis (in cluster A), WNT signalling (in cluster B), endochondral ossification (in cluster C), matrix metalloproteinases and the ACE/RAGE pathway (in cluster D), and the Toll-like receptor, and IL-1 signalling pathways (in cluster E). Moreover, the dynamic profiles of these transcriptional changes were assigned to cellular compartments of the knee joint. Classifying the molecular processes associated with the development of cartilage degeneration provides novel insight into the OA disease process. Our study identified groups of co-regulated genes that share functional relationships and that may play an important role in the early and intermediate stages of OA.

The Role of Sirtuins in Cartilage Homeostasis and Osteoarthritis

The past decade has witnessed many advances in the understanding of sirtuin biology and related regulatory circuits supporting the capacity of these proteins to serve as energy-sensing molecules that contribute to healthspan in various tissues, including articular cartilage. Hence, there has been a significant increase in new investigations that aim to elucidate the mechanisms of sirtuin function and their roles in cartilage biology, skeletal development, and pathologies such as osteoarthritis (OA), rheumatoid arthritis (RA), and intervertebral disc degeneration (IVD). The majority of the work carried out to date has focused on SIRT1, although SIRT6 has more recently become a focus of some investigations. In vivo work with transgenic mice has shown that Sirt1 and Sirt6 are essential for maintaining cartilage homeostasis and that the use of sirtuin-activating molecules such as resveratrol may have beneficial effects on cartilage anabolism. Current thinking is that SIRT1 exerts positive effects on cartilage by encouraging chondrocyte survival, especially under stress conditions, which may provide a mechanism supporting the use of sirtuin small-molecule activators (STACS) for future therapeutic interventions in OA and other degenerative pathologies of joints, especially those that involve articular cartilage.

Comparison of Intra-articular Injection of Hyaluronic Acid and N-Acetyl Cysteine in the Treatment of Knee Osteoarthritis: A Pilot Study

Objective To compare the relative effectiveness of intra-articular N-acetyl cysteine (NAC) and hyaluronic acid (HA) on pain, function and cartilage degradation markers in patients with mild to moderate knee osteoarthritis (OA). Design We prospectively conducted a clinical trial with 20 patients having a diagnosis of Kellgren-Lawrence grade 2-3 knee OA, and randomly allocated to the HA or NAC groups. Groups were matched on age, sex, and body mass index. Injections of 3-mL HA (Hylan G-F 20) or 3-mL NAC (Asist ampoule) were administered as a single shot. Functional status and pain were evaluated before and after injection, using the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and the visual analogue scale (VAS) scores. Pre- and posttreatment concentrations of serum C-reactive protein (CRP), synovial fluid chondroitin-6-sulfate (C-6S), matrix metalloproteinase-3 (MMP-3), cross-linked C-terminal telopeptide of type 2 collagen (CTX-II), total oxidant status (TOS), and total antioxidant concentration (TAC) were obtained. Results WOMAC, VAS scores, and CRP levels were comparable between groups prior to treatment. Both HA and NAC produced comparable reductions in TOS and MMP-3. NAC was more effective in reducing C-6S and CTX-II ( P < 0.05). No effects on TAC were noted. Conclusions NAC is effective in lowering some cartilage degradation markers, with comparable outcomes to HA for pain and function. NAC could provide a cheaper alternative to HA for intra-articular injection treatment of mild to moderate knee OA. Future placebo controlled trials are warranted to evaluate effectiveness in a larger patient population with a wider range of age and OA severity.

Decrease of Markers Related to Bone Erosion in Serum of Patients with Musculoskeletal Disorders after Serial Low-Dose Radon Spa Therapy

Musculoskeletal disorders (MSDs) are the most frequent cause of disability in Europe. Reduced mobility and quality of life of the patients are often associated with pain due to chronic inflammation. The inflammatory process, accompanied by a destruction of the cartilage and bone tissue, is discussed as a result of (A) the infiltration of immune cells into the joints, (B) an altered homeostasis of the joint cavity (synovium) with a critical role of bone remodeling cells, and (C) release of inflammatory factors including adipokines in the arthritic joint. In addition to the classical medication, low-dose radiation therapy using photons or radon spa treatments has shown to reduce pain and improve the mobility of the patients. However, the cellular and molecular mechanisms of anti-inflammatory effects of radon are yet poorly understood. We analyzed blood and serum samples from 32 patients, suffering from MSDs, who had been treated in the radon spa in Bad Steben (Germany). Before and after therapy, we measured the levels of markers related to bone metabolism (collagen fragments type-1, cartilage oligomeric matrix protein, receptor activator of NFκB ligand, and osteoprotegerin) in the serum of patients. In addition, adipokines related to inflammation (visfatin, leptin, resistin, and adiponectin) were analyzed. Some of these factors are known to correlate with disease activity. Since T cells play an important role in the progression of the disease, we further analyzed in blood samples the frequency of pro- and anti-inflammatory T cell subpopulations (CD4⁺IL17⁺ T cells and CD4⁺FoxP3⁺ regulatory T cells). Overall, we found a decrease of collagen fragments (CTX-I), indicating decreased bone resorption, presumably by osteoclasts, in the serum of MSD patients. We also observed reduced levels of visfatin and a consistent trend toward an increase of regulatory T cells in the peripheral blood, both indicating attenuation of inflammation. However, key proteins of bone metabolism were unchanged on a systemic level, suggesting that these factors act locally after radon spa therapy of patients with MSDs.

Evaluation of the effect of salmon nasal proteoglycan on biomarkers for cartilage metabolism in individuals with knee joint discomfort: A randomized double-blind placebo-controlled clinical study

A randomized double-blind placebo-controlled clinical trial was conducted to evaluate the chondroprotective action of salmon nasal cartilage proteoglycan on joint health. The effect of oral administration of proteoglycan (10 mg/day) on cartilage metabolism was evaluated in individuals with knee joint discomfort but without diagnosis of knee osteoarthritis. The average age of patients was 52.6±1.1 years old. The effect of proteoglycan was evaluated by analyzing markers for type II collagen degradation (C1,2C) and synthesis (PIICP), and the ratio of type II collagen degradation to synthesis. The results indicated that the change in C1,2C levels significantly differed in the proteoglycan group compared with the placebo group following 16 weeks intervention among subjects with high levels of knee pain and physical dysfunction (total score of Japan Knee Osteoarthritis Measure ≥41) and subjects with constant knee pain (both P<0.05). There was a greater increase in PIICP levels in the proteoglycan group than the placebo group following intervention, although this difference was not significant in both sets of patients. Thus, the C1,2C/PIICP ratios decreased in the proteoglycan group, whereas they slightly increased in the placebo group following the intervention. Furthermore, no test supplement-related adverse events were observed during the intervention. Therefore, oral administration of salmon nasal cartilage proteoglycan at a dose of 10 mg/day may exert a chondroprotective action in subjects with knee joint discomfort. This effect was achieved by improving cartilage metabolism (reducing type II collagen degradation and enhancing type II collagen synthesis), without causing apparent adverse effects.