Osteoarthritis year in review 2019: epidemiology and therapy

Silenced LASP1 interacts with DNMT1 to promote TJP2 expression and attenuate articular cartilage injury in mice by suppressing TJP2 methylation

To investigate the regulatory mechanisms and effects of LIM and SH3 protein 1 (LASP1) on osteoarthritis (OA). IL-1β was used to induce OA in cell models. Viability and apoptosis of chondrocytes were assessed. The expressions of tumor necrsis factor-α (TNF-α) and IL-6 were measured by ELISA kit, and Quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot were performed to test the expression of related proteins. The STRING database was used to predict the relationship between LASP1 and DNA methyltransferase 1 (DNMT1). The tight junction protein 2 (TJP2) and Gene Expression Omnibus data were analyzed for differential OA genes. Methylation-specific PCR detected methylation of the TJP2 promoter region, and chromatin immunoprecipitation detected the enrichment of DNMT1 in the TJP2 promoter region. Safranin O-Fast Green staining and hematoxylin and eosin staining were used to determine the OARSI score and evaluate the pathological conditions of the joint tissues. LASP1 was highly expressed in IL-1β-induced cell models. Silencing of LASP1 promoted chondrocyte proliferation and expression of Collagen II and Aggrecan and inhibited chondrocyte apoptosis, inflammatory factors, and matrix metalloprotein expression. TJP2 is weakly expressed in OA models, and LASP1 promotes methylation of the TJP2 promoter region by interacting with DNMT1. Silencing of LASP1 attenuated IL-1β-induced chondrocyte degeneration by promoting TJP2 expression. Similarly, silencing LASP1 promotes TJP2 expression to alleviate articular cartilage injury in mice with OA. Silencing of LASP1 inhibited the methylation of the TJP2 promoter region by interacting with DNMT1, thereby alleviating articular cartilage damage in OA mice.

The Effects of Ultrasound-Guided Intra-Articular Injections with Hyaluronic Acid and Corticosteroids in Patients with Hip Osteoarthritis: A Long-Term Real-World Analysis

Intra-articular (IA) ultrasound-guided hip injections are currently considered a cornerstone of the conservative management of symptomatic hip osteoarthritis (HOA), although their effect on clinical outcomes has not been fully elucidated.The purpose of this study is to investigate the effectiveness of ultrasound-guided IA hip injections of hyaluronic acid (HA) with or without corticosteroids (CS) on pain relief and functional improvement in patients with HOA. In total, 167 patients with HOA were assessed at baseline (T0) and 12 months after injection (T1) using the VAS and GLFS scores. The sample consisted mainly of female subjects (58.1%), presenting an average age of 70.6 ± 12.2 years and grade 3 HOA (63.9%) according to the Kellgren-Lawrence classification. Most of the patients (76.2%) underwent unilateral hip injection with a combination of medium-high molecular weight HA (1500-2000 kDa) and CS. At T1, lower use of anti-inflammatory drugs, an increase in the consumption of chondroprotectors, and an overall reduction of instrumental physical therapies and therapeutic exercise were recorded. In addition, a statistically significant intragroup and between-group decrease observed at T1 for both the VAS and GLFS. Study results suggested that intra-articular hip injections with HA alone and with CS could represent a useful therapeutic tool for pain reduction and functional improvement for patients with hip osteoarthritis.

Berberine oleanolic acid complex salt grafted hyaluronic acid/silk fibroin (BOA-g-HA/SF) composite scaffold promotes cartilage tissue regeneration under IL-1β caused stress

Since inflammatory cytokines cause stress to chondrocytes and the failure of cartilage defects repair with cartilage tissue engineering, it is necessary to develop a scaffold to maintain cartilage regeneration under inflammatory factors caused stress. Following a berberine-oleanolic acid (OA) complex salt (BOA) was grafted to hyaluronic acid (HA) to obtain water soluble BOA-g-HA, it mixed with silk fibroin (SF) to prepared 4 solutions, which contained 30 mg/mL SF and 0.75, 1.5, 2.25, and 3.0 mg/mL BOA-g-HA respectively. They were lyophilized to fabricate BOA-g-HA/SF-1, BOA-g-HA/SF-2, BOA-g-HA/SF-3, and BOA-g-HA/SF-4 composite scaffolds respectively. All prepared scaffolds displayed porous network structure and exhibited promising mechanical properties for tissue engineering applications. Among them, the BOA-g-HA/SF-3 composite scaffold showed the highest influence on maintaining chondrocytic phenotype of chondrocytes under IL-1β induced stress. Following SF, HA/SF, and BOA-g-HA/SF-3 composite scaffolds with seeded chondrocytes were treated with IL-1β induction for 1 week, specimens were incubated with cell culture medium for 3 week or were subcutaneously implanted into nude mice for 4 weeks. The results demonstrated that the BOA-g-HA/SF-3 composite scaffold promotes cartilage tissue regeneration in vitro and in vivo under IL-1β caused stress, suggesting that it can be potential applied for repairing cartilage defects in osteoarthritis patients.

Suramin analogues protect cartilage against osteoarthritic breakdown by increasing levels of tissue inhibitor of metalloproteinases 3 (TIMP-3) in the tissue

Osteoarthritis is a chronic degenerative joint disease affecting millions of people worldwide, with no disease-modifying drugs currently available to treat the disease. Tissue inhibitor of metalloproteinases 3 (TIMP-3) is a potential therapeutic target in osteoarthritis because of its ability to inhibit the catabolic metalloproteinases that drive joint damage by degrading the cartilage extracellular matrix. We previously found that suramin inhibits cartilage degradation through its ability to block endocytosis and intracellular degradation of TIMP-3 by low-density lipoprotein receptor-related protein 1 (LRP1), and analysis of commercially available suramin analogues indicated the importance of the 1,3,5-trisulfonic acid substitutions on the terminal naphthalene rings for this activity. Here we describe synthesis and structure-activity relationship analysis of additional suramin analogues using ex vivo models of TIMP-3 trafficking and cartilage degradation. This showed that 1,3,6-trisulfonic acid substitution of the terminal naphthalene rings was also effective, and that the protective activity of suramin analogues depended on the presence of a rigid phenyl-containing central region, with para/para substitution of these phenyl rings being most favourable. Truncated analogues lost protective activity. The physicochemical characteristics of suramin and its analogues indicate that approaches such as intra-articular injection would be required to develop them for therapeutic use.

Targeting regulated chondrocyte death in osteoarthritis therapy

In vivo articular cartilage degeneration is an essential hallmark of osteoarthritis (OA), involving chondrocyte senescence, extracellular matrix degradation, chondrocyte death, cartilage loss, and bone erosion. Among them, chondrocyte death is one of the major factors leading to cartilage degeneration. Many studies have reported that various cell death modes, including apoptosis, ferroptosis, and autophagy, play a key role in OA chondrocyte death. Currently, there is insufficient understanding of OA pathogenesis, and there remains a lack of treatment methods to prevent OA and inhibit its progression. Studies suggest that OA prevention and treatment are mainly directed to arrest premature or excessive chondrocyte death. In this review, we a) discuss the forms of death of chondrocytes and the associations between them, b) summarize the critical factors in chondrocyte death, c) discuss the vital role of chondrocyte death in OA, d) and, explore new approaches for targeting the regulation of chondrocyte death in OA treatment.

Identification of EGFR as an essential regulator in chondrocytes ferroptosis of osteoarthritis using bioinformatics, in vivo, and in vitro study

Objective

The mechanisms of chondrocytes ferroptosis in osteoarthritis (OA) have not yet been fully elucidated. This study aimed to identify key ferroptosis related genes (FRGs) involved in chondrocytes ferroptosis.

Methods

LASSO, SVM-RFE, and receiver operating characteristic curve (ROC) were performed to screen key differentially expressed FRGs (DEFRGs). Functional analyses were conducted using GO, and KEGG analyses. Unsupervised clustering analysis was used to identify ferroptosis related patterns. The CeRNA network was constructed to predict the upstream miRNAs and lncRNAs. Finally, we validated the role of EGFR in chondrocytes ferroptosis using in vivo and in vitro experiments.

Results

A total of 42 DEFRGs were identified between OA and normal cartilages. GO and KEGG analyses indicated that these DEFRGs were significantly engaged in ferroptosis related biological processes and pathways, such as cellular response to oxidative stress, positive regulation of programmed cell death, MAPK and PI3K-Akt signaling pathways. Moreover, four key DEFRGs, including ACSF2, AURKA, EGFR, and KLHL24, were considered as potential biomarkers of OA. Moreover, two distinct ferroptosis related patterns were determined, and a total of 882 differentially expressed genes were identified which might participate in extracellular matrix degradation and inflammatory response. In addition, the CeRNA network showed that EGFR could be competitively regulated by 3 lncRNAs and 4 miRNAs. Significantly, the expression of EGFR was downregulated in human OA cartilages, OA mouse model, and erastin induced chondrocytes. EGFR inhibition could induce the occurrence of chondrocytes ferroptosis and ECM degradation which could be reversed by the addition of Ferrostatin-1.

Conclusion

Our study has identified ACSF2, AURKA, EGFR, and KLHL24 as ferroptosis-related biomarkers in OA. Furthermore, we have conducted a preliminary investigation into the role of EGFR in regulating chondrocytes ferroptosis. These findings offer novel insights into the molecular mechanisms underlying OA.

Tizoxanide as a novel theraputic candidate for osteoarthritis

Osteoarthritis (OA) is a frequently seen degenerative joint disease in the elderly. Its pathogenesis is highly related to the local inflammatory reaction and autophagy. Tizoxanide (Tiz), the main active metabolite of nitazoxanide, has proved its anti-inflammatory properties in several diseases. However, the exact role of Tiz in OA remains to explore. In this study, we investigated the anti-arthritic effects and the underlying molecular mechanisms of Tiz on rat OA. The results showed that Tiz could attenuate the IL-1β-induced inflammatory disorders, cartilage matrix damage and autophagy reduction in rat chondrocytes. Moreover, employment of autophagy inhibitor 3-methyladenine (3-MA) could antagonize the protective effects of Tiz in IL-1β-treated rat chondrocytes. Additionally, Tiz also inhibited the IL-1β-induced PI3K/AKT/mTOR and P38/JNK phosphorylation in chondrocytes. In vivo, intra-articular injection of Tiz could significantly alleviate the progression of cartilage damage in rat OA model. Briefly, our study demonstrated the therapeutic potential of Tiz in OA, suggesting that Tiz administration might serve as a promising strategy in OA therapy.

Relations between Structure/Composition and Mechanics in Osteoarthritic Regenerated Articular Tissue: A Machine Learning Approach

In the context of a large animal model of early osteoarthritis (OA) treated by orthobiologics, the purpose of this study was to reveal relations between articular tissues structure/composition and cartilage viscoelasticity. Twenty-four sheep, with induced knee OA, were treated by mesenchymal stem cells in various preparations-adipose-derived mesenchymal stem cells (ADSCs), stromal vascular fraction (SVF), and amniotic endothelial cells (AECs)-and euthanized at 3 or 6 months to evaluate the (i) biochemistry of synovial fluid; (ii) histology, immunohistochemistry, and histomorphometry of articular cartilage; and (iii) viscoelasticity of articular cartilage. After performing an initial analysis to evaluate the correlation and multicollinearity between the investigated variables, this study used machine learning (ML) models-Variable Selection Using Random Forests (VSURF) and Extreme Gradient Boosting (XGB)-to classify variables according to their importance and employ them for interpretation and prediction. The experimental setup revealed a potential relation between cartilage elastic modulus and cartilage thickness (CT), synovial fluid interleukin 6 (IL6), and prostaglandin E2 (PGE2), and between cartilage relaxation time and CT and PGE2. SVF treatment was the only limit on the deleterious OA effect on cartilage viscoelastic properties. This work provides indications to future studies aiming to highlight these and other relationships and focusing on advanced regeneration targets.

Lipid peroxidation in osteoarthritis: focusing on 4-hydroxynonenal, malondialdehyde, and ferroptosis

Osteoarthritis (OA) is a multifactorial and increasingly prevalent degenerative disease that affects the whole joint. The pathogenesis of OA is poorly understood and there is a lack of therapeutic interventions to reverse the pathological process of this disease. Accumulating studies have shown that the overproduction of reactive oxygen species (ROS) and ROS-induced lipid peroxidation are involved in the pathogenesis of OA. 4-Hydroxy-2-nonenal (4-HNE) and malondialdehyde (MDA) have received considerable attention for their role in cartilage degeneration and subchondral bone remodeling during OA development. Ferroptosis is a form of cell death characterized by a lack of control of membrane lipid peroxidation and recent studies have suggested that chondrocyte ferroptosis contributes to OA progression. In this review, we aim to discuss lipid peroxidation-derived 4-HNE and MDA in the progression of OA. In addition, the therapeutic potential for OA by controlling the accumulation of lipid peroxidation and inhibiting chondrocyte ferroptosis are discussed.

Treatment with CR500® improves algofunctional scores in patients with knee osteoarthritis: a post-market confirmatory interventional, single arm clinical investigation

BACKGROUND

Knee osteoarthritis (OA) is a progressive and degenerative condition. Several pharmacological and non-pharmacological treatments are able to improve the OA symptoms and the structural characteristics of the affected joints. Among these, infiltrative therapy with hyaluronic acid (HA) is the most used and consolidated procedure for the pain management. The addition of skin conditioning peptides to HA promotes the cartilage remodeling processes and a better permeation of the HA-based gel containing a peptide mixture, CR500®. Furthermore, the topic route of administration is convenient over the routinely used intra-articular injective procedures. In this study, the effectiveness of CR500® was evaluated in terms of improvement of the algo-functional symptoms related to unilateral knee OA.

METHODS

38 mild and moderate OA patients were enrolled at a screening visit (V-1), treated at baseline visit (V1), and then continued the topical application of CR500® twice a week for 4 weeks, and followed-up for 3 visits (V2-V4) from week 2 to 4. Lequesne Knee Index (LKI) and Knee injury and Osteoarthritis Outcome Score (KOOS) were collected. Synovial fluid was collected and used for the quantification of neoepitope of type II collagen (C2C), C-terminal telopeptide of type II collagen (CTX-II), type II collagen propeptide (CPII), tumor necrosis factor alpha (TNFα) and HA. The expression of CD11c and CD206 was evaluated on cell pellets.

RESULTS

Three patients were excluded, thus 35 patients were included in the analysis. The treatment with CR500® was safe and well tolerated, with 7.9% patients had mild adverse events, not related to the device. The LKI total score showed a significant decrease from V1 to V4. KOOS score also showed a significant improvement of patient condition at V2, V3 and V4 in comparison with V1 for all subscales, except for KOOS sport subscale which improved only from V3. At V1 a negative correlation among KOOS pain subscale values and C2C, CPII and TNFα levels was observed, as well as a positive correlation between KOOS pain subscale and CD11c/CD206 ratio.

CONCLUSION

CR500® is safe and appear to be effective in improving pain and function in OA patients during the 4 weeks of treatment.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT05661162. This trial was registered on 22/12/2022.

Effects of genus Epimedium in the treatment of osteoarthritis and relevant signaling pathways

Osteoarthritis (OA) is a common chronic degenerative joint disease in clinical practice with a high prevalence, especially in the elderly. Traditional Chinese Medicine (TCM) believes that OA belongs to the category of "Bi syndrome" and the "bone Bi syndrome". The etiology and pathogenesis lie in the deficiency of the liver and kidney, the deficiency of Qi and blood, and external exposure to wind, cold, and dampness. Epimedium is a yang-reinforcing herb in TCM, which can tonify the liver and kidney, strengthen muscles and bones, dispel wind, cold and dampness, and can treat both the symptoms and the root cause of "bone Bi syndrome". In addition, Epimedium contains a large number of ingredients. Through modern science and technology, more than 270 compounds have been found in Epimedium, among which flavonoids are the main active ingredients. Therefore, our study will review the effects and mechanisms of genus Epimedium in treating OA from two aspects: (1) Introduction of Epimedium and its main active ingredients; (2) Effects of Epimedium and its active ingredients in treating OA and relevant signaling pathways, in order to provide more ideas for OA treatment.

Post-traumatic osteoarthritis: the worst associated injuries and differences in patients' profile when compared with primary osteoarthritis

BACKGROUND

The estimated prevalence of post-traumatic osteoarthritis (PTOA) is 10-12% and in this study 12.4%. Different knee and hip injuries have been identified as risk factors for PTOA, but there is no consensus regarding the most painful and disabling injuries. Identifying these injuries might help in the prevention of PTOA. Additionally, patients with PTOA have a higher risk for complications after arthroplasty than patients with primary OA, perhaps due to differences in the profile and comorbidity that might help to explain the difference. This work aims 1) to identify the most common past injuries associated with the most painful and disabling PTOA cases in non-athlete patients and 2) to compare the comorbidities and characteristics between PTOA and primary OA.

METHODS

Retrospective hospital-based cohort study with 1290 participants with joint complaints or who received arthroplasty. Medical records included demographic information, diagnosis, medication, smoking, alcohol history and comorbidities. Data from January 2012 orthopaedic consults till December 2019 was reviewed and had the type and date of injury, pain score by the numerical rating scale and walking disability. Odds Ratio (OR) and 95% confidence intervals are presented.

RESULTS

There were 641 cases with primary OA (65% females) and 104 with PTOA (61% males). Patients with PTOA were 7.5 years younger (P < 0.001), reported more alcohol consumption (P = 0.01) and had higher odds of osteoporotic fractures (OP) and psychosis than patients with primary OA (OR = 2.0, CI = 1.06-3.78 and OR = 2.90, CI = -0.91-9.18, respectively). Knee fractures were most common in males and hip fractures in females (31% and 37.5%, respectively, P < 0.005). The PTOA-associated injuries with the highest pain and disability scores were meniscal injuries and hip fractures. Besides, in the group with primary OA, there were more diabetes, hypertension and hypothyroidism cases than in PTOA. However, after adjustment, differences were only significant for diabetes (OR_adj = 1.78, CI = 1.0-3.2).

CONCLUSIONS

Past meniscal injuries and hip fractures were the most relevant PTOA-associated injuries regarding pain and walking disability. This, together with differences in their profile when compared with primary OA, might help to decide the orthopaedic management of these injuries to prevent complications such as PTOA and recurrence, with appropriate preoperative planning, surgery choice and comorbidity treatment.

Adipokines as Predictive Biomarkers for Training Adaptation in Subjects with Multimorbidity-A Hypothesis-Generating Study

BACKGROUND

Physical exercise exerts a positive effect on many chronic conditions, specifically lifestyle-related diseases such as overweight and obesity, type 2 diabetes mellitus (T2DM), cardiovascular conditions and osteoarthritis (OA). As a result of common risk factors, most of these patients present with multiple conditions. Exercise- and disease-related biomarkers, such as adipokines, are emerging tools in training supervision and regulation; however, their significance in subjects with multimorbidities is unknown.

SUBJECTS AND METHODS

To address this issue, adipokines leptin, adiponectin and resistin were assessed in a cohort of subjects with multimorbidities (n = 39) presenting with at least two of the abovementioned conditions or relevant risk factors before and after a six-month exercise and lifestyle intervention program ('MultiPill-Exercise'), and correlated with training adaptation, namely changes in relative maximum oxygen uptake (V·O2max).

RESULTS

There was a significant negative correlation between baseline leptin concentrations and training effect for relative V·O2max (after three months: rho = -0.54, p = 0.020 *; after six months: rho = -0.45, p = 0.013 *), with baseline leptin explaining 35% of the variance in delta relative V·O2max after three months and 23% after six months.

CONCLUSIONS

Leptin might be a suitable surrogate biomarker in the context of exercise-based lifestyle intervention programs in subjects with multimorbidity.

Mesenchymal Stromal Cells-Derived Extracellular Vesicles as Potential Treatments for Osteoarthritis

Osteoarthritis (OA) is a degenerative disease of the joints characterized by cartilage damage and severe pain. Despite various pharmacological and surgical interventions, current therapies fail to halt OA progression, leading to high morbidity and an economic burden. Thus, there is an urgent need for alternative therapeutic approaches that can effectively address the underlying pathophysiology of OA. Extracellular Vesicles (EVs) derived from mesenchymal stromal cells (MSCs) represent a new paradigm in OA treatment. MSC-EVs are small membranous particles released by MSCs during culture, both in vitro and in vivo. They possess regenerative properties and can attenuate inflammation, thereby promoting cartilage healing. Importantly, MSC-EVs have several advantages over MSCs as cell-based therapies, including lower risks of immune reactions and ethical issues. Researchers have recently explored different strategies, such as modifying EVs to enhance their delivery, targeting efficiency, and security, with promising results. This article reviews how MSC-EVs can help treat OA and how they might work. It also briefly discusses the benefits and challenges of using MSC-EVs and talks about the possibility of allogeneic and autologous MSC-EVs for medical use.

Hip and Knee Osteoarthritis in Patients with Chronic Myeloproliferative Neoplasms: A Cross-Sectional Study

BACKGROUND

Osteoarthritis (OA) is a progressive degenerative disease with an inflammatory background. Chronic myeloproliferative neoplasms (MPN) are clonal hematopoietic disorders characterized by chronic inflammation and a tendency for connective tissue remodeling.

AIM

This study aimed to investigate the prevalence and associated risk factors of symptomatic OA (sOA) in MPN patients.

PATIENTS AND METHODS

A total of 100 consecutive MPN (39 essential-thrombocythemia, 34 polycythemia-vera, 27 myelofibrosis) patients treated in two community hematologic centers were cross-sectionally evaluated. Patients were required to have both symptoms attributable to hip and/or knee OA and radiographic confirmation to be considered as having sOA.

RESULTS

The prevalence of hip and/or knee sOA was significantly higher among MPN patients than the previously reported prevalence in the general population of similar age (61% vs. 22%, p < 0.001). Hip sOA was present in 50%, knee sOA in 51% and sOA of both localizations in 41% of patients. A high proportion of MPN patients had radiographic signs of hip OA (94%) and knee OA (98%) in the presence of attributable symptoms. Among the other factors, sOA was univariately associated with the presence of JAK2 mutation, myelofibrosis phenotype, older age, higher body weight, and higher MPN-SAF score (p < 0.050 for all analyses). In the multivariate analysis, older age (odds ratio = 1.19, 95% confidence interval-CI 1.06-1.33) and higher body weight (OR = 1.15, 95% CI 1.06-1.25) were recognized as independent risk factors for sOA. On the other hand, cytoreductive treatment was a protective factor for sOA (OR = 0.07, 95% CI 0.006-0.86).

CONCLUSIONS

The prevalence of sOA in MPN patients was higher than that in the general population and seems to correlate with older age, increased myeloproliferation and a higher inflammatory state. Whether cytoreductive treatment may postpone OA development in MPN patients warrants additional confirmation.

Acupuncture for treatment of knee osteoarthritis: A clinical practice guideline

CLINICAL QUESTION

Is acupuncture effective in treating knee osteoarthritis (KOA)?

CURRENT PRACTICE

Although increasingly used in the clinical setting, acupuncture is not mentioned or weakly recommended in guidelines for the treatment of KOA.

RECOMMENDATIONS

We suggest acupuncture rather than no treatment in adult KOA (weak recommendation, moderate certainty evidence), and acupuncture combined with nonsteroidal anti-inflammatory drugs (NSAIDs) rather than acupuncture alone when KOA symptoms are severe (weak recommendation, moderate certainty evidence), with duration of acupuncture for 4-8 weeks depending on KOA severity and treatment response (weak recommendation, moderate certainty evidence), and discussing with patients in shared decision-making.

HOW THIS GUIDELINE WAS CREATED

This rapid recommendation was developed following the Making GRADE the Irresistible Choice (MAGIC) methodological framework. First, the clinical specialist identified the topic of recommendation and demand for evidence. Then the independent evidence synthesis group performed a systematic review to summarize available evidence and evaluate the evidence using the GRADE approach. Finally, the clinical specialist group produced recommendations for practice through a consensus procedure.

THE EVIDENCE

The linked systematic review and meta-analysis included 9422 KOA patients, 61.1% of whom were women. The median mean age was 61.8 years. Compared with no treatment, acupuncture had beneficial effect on KOA in improving the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) total score (moderate certainty evidence), and WOMAC pain (very low certainty evidence), WOMAC stiffness (low certainty evidence), and WOMAC function (low certainty evidence) subscale scores. Compared with usual care, acupuncture improved WOMAC stiffness subscale score (moderate certainty evidence). Subgroup analyses showed different effects in the improvement of WOMAC total scores by different durations of acupuncture and whether acupuncture combined with NSAIDs, but no difference between manual acupuncture and electroacupuncture was found.

UNDERSTANDING THE RECOMMENDATIONS

Compared with no treatment, acupuncture is suggested to reduce pain, stiffness, and disfunction in KOA patients, ultimately improving the patient's health status. Acupuncture can be used as an alternative therapy when usual care is ineffective or there are adverse reactions so that patients can no longer continue the treatment. Manual acupuncture or electroacupuncture is suggested for 4-8 weeks to improve the health status of KOA. The patient's values and preferences should be considered when selecting acupuncture for KOA treatment.

When are patients with osteoarthritis referred for surgery?

Current treatment strategies in hip and knee osteoarthritis (OA) involve a combined approach that includes not only modification of risk factors and conservative treatment but also joint-preserving surgical therapy in the early stages, or joint replacement in late OA. With the recent development of new etiological concepts (i.e. hip dysplasia and femoroacetabular impingement as major risk factors for hip OA), treatment alternatives for joint preservation could be extended significantly. Satisfactory results of osteotomies and other reconstructive procedures around hip and knee joints can only be expected in early OA (Kellgren/Lawrence grade 0-II). If patients with advanced radiographic OA grades III-IV do not respond to conservative treatment over at least 3 months and express a relevant burden of disease, joint replacement might be considered. Prior to surgery, potential contraindications must be excluded, patient expectations need to be discussed, and modifiable risk factors, which may negatively influence the outcome, should be optimized.

Stromal cell-derived factor-1α regulates chondrogenic differentiation via activation of the Wnt/β-catenin pathway in mesenchymal stem cells

BACKGROUND

Mesenchymal stem cells (MSCs) have been applied to treat degenerative articular diseases, and stromal cell-derived factor-1α (SDF-1α) may enhance their therapeutic efficacy. However, the regulatory effects of SDF-1α on cartilage differentiation remain largely unknown. Identifying the specific regulatory effects of SDF-1α on MSCs will provide a useful target for the treatment of degenerative articular diseases.

AIM

To explore the role and mechanism of SDF-1α in cartilage differentiation of MSCs and primary chondrocytes.

METHODS

The expression level of C-X-C chemokine receptor 4 (CXCR4) in MSCs was assessed by immunofluorescence. MSCs treated with SDF-1α were stained for alkaline phosphatase (ALP) and with Alcian blue to observe differentiation. Western blot analysis was used to examine the expression of SRY-box transcription factor 9, aggrecan, collagen II, runt-related transcription factor 2, collagen X, and matrix metalloproteinase (MMP)13 in untreated MSCs, of aggrecan, collagen II, collagen X, and MMP13 in SDF-1α-treated primary chondrocytes, of glycogen synthase kinase 3β (GSK3β) p-GSK3β and β-catenin expression in SDF-1α-treated MSCs, and of aggrecan, collagen X, and MMP13 in SDF-1α-treated MSCs in the presence or absence of ICG-001 (SDF-1α inhibitor).

RESULTS

Immunofluorescence showed CXCR4 expression in the membranes of MSCs. ALP stain was intensified in MSCs treated with SDF-1α for 14 d. The SDF-1α treatment promoted expression of collagen X and MMP13 during cartilage differentiation, whereas it had no effect on the expression of collagen II or aggrecan nor on the formation of cartilage matrix in MSCs. Further, those SDF-1α-mediated effects on MSCs were validated in primary chondrocytes. SDF-1α promoted the expression of p-GSK3β and β-catenin in MSCs. And, finally, inhibition of this pathway by ICG-001 (5 µmol/L) neutralized the SDF-1α-mediated up-regulation of collagen X and MMP13 expression in MSCs.

CONCLUSION

SDF-1α may promote hypertrophic cartilage differentiation in MSCs by activating the Wnt/β-catenin pathway. These findings provide further evidence for the use of MSCs and SDF-1α in the treatment of cartilage degeneration and osteoarthritis.

A cytokine-induced spheroid-based in vitro model for studying osteoarthritis pathogenesis

Given the lack of in vitro models faithfully reproducing the osteoarthritis (OA) disease on-set, this work aimed at manufacturing a reliable and predictive in vitro cytokine-based Articular Cartilage (AC) model to study OA progression. Cell spheroids of primary human fetal chondrocytes (FCs) and h-TERT mesenchymal stem cells differentiated chondrocytes (Y201-C) were analysed in terms of growth kinetics, cells proliferation and apoptosis over 10 days of culture, in healthy condition or in presence of cytokines (interleukin-1ß, -6 and TNF-α). Then, the spheroids were assembled into chondrospheres using a bottom-up strategy, to obtain an in vitro cytokines-induced OA model. The resulting chondrospheres were evaluated for gene expression and anabolic ECM proteins. Compared to the healthy environment, the simulated OA environment induced chondrocyte hyperproliferation and apoptotic pathway, decreased expression of anabolic ECM proteins, and diminished biosynthetic activity, resembling features of early-stage OA. These characteristics were observed for both Y201-C and HC at high and low concentrations of cytokines. Both HC and Y201-C demonstrated the suitability for the manufacturing of a scaffold-free in vitro OA model to facilitate studies into OA pathogenesis and therapeutic strategies. Our approach provides a faithful reproduction of early-stage osteoarthritis, demonstrating the ability of obtaining different disease severity by tuning the concentration of OA-related cytokines. Given the advantages in easy access and more reproducible performance, Y201-C may represent a more favourable source of chondrocytes for establishing more standardized protocols to obtain OA models.

Review of cooled radiofrequency ablation utilization for the treatment of symptomatic advanced knee arthritis and total knee arthroplasty

Degenerative knee osteoarthritis is a progressive debilitating condition that affects millions of people worldwide. Most patients experience limited range of motion, inflammation, swelling, and pain. Management options can lead to short- and long-term pain relief. Short-term pain relief usually involves conservative medical treatments such as NSAIDs, weight loss, physical therapy, and corticosteroid injections. The ultimate long-term pain relief treatment method involves total knee arthroplasty. The treatment algorithm for knee OA also includes managing pain until a patient is eligible for arthroplasty. Furthermore, about 20% of patients experience chronic pain after TKA without complications such as hardware loosening and infection with limited treatment options. The pathophysiology of this is unknown. Cooled radiofrequency ablation has been demonstrated to be clinically effective by disrupting the integrity of deep sensory nerves and hence interfering with transmission of pain signal. The analgesic effect after c-RFA has been reported up to 24 months. Here, we present an overview of the clinical application of cooled radiofrequency ablation and a summary of its effectiveness in the treatment of pain in the setting of advanced OA and symptomatic TKA.

Human-specific duplicate CHRFAM7A gene is associated with more severe osteoarthritis and amplifies pain behaviours

OBJECTIVES

CHRFAM7A is a uniquely human fusion gene that functions as a dominant negative regulator of alpha 7 acetylcholine nicotinic receptor (α7nAChR) in vitro. This study determined the impact of CHRFAM7A on α7nAChR agonist responses, osteoarthritis (OA) severity and pain behaviours and investigated mechanisms.

METHODS

Transgenic CHRFAM7A (TgCHRFAM7A) mice were used to determine the impact of CHRFAM7A on knee OA histology, pain severity in OA and other pain models, response to nAchR agonist and IL-1β. Mouse and human cells were used for mechanistic studies.

RESULTS

Transgenic (Tg) TgCHRFAM7A mice developed more severe structural damage and increased mechanical allodynia than wild type (WT) mice in the destabilisation of medial meniscus model of OA. This was associated with a decreased suppression of inflammation by α7nAchR agonist. TgCHRFAM7A mice displayed a higher basal sensitivity to pain stimuli and increased pain behaviour in the monoiodoacetate and formalin models. Dorsal root ganglia of TgCHRFAM7A mice showed increased macrophage infiltration and expression of the chemokine fractalkine and also had a compromised antinociceptive response to the α7nAchR agonist nicotine. Both native CHRNA7 and CHRFAM7A subunits were expressed in human joint tissues and the CHRFAM7A/CHRNA7 ratio was increased in OA cartilage. Human chondrocytes with two copies of CHRFAM7A had reduced anti-inflammatory responses to nicotine.

CONCLUSION

CHRFAM7A is an aggravating factor for OA-associated inflammation and tissue damage and a novel genetic risk factor and therapeutic target for pain.

Molecular Basic of Pharmacotherapy of Cytokine Imbalance as a Component of Intervertebral Disc Degeneration Treatment

Intervertebral disc degeneration (IDD) and associated conditions are an important problem in modern medicine. The onset of IDD may be in childhood and adolescence in patients with a genetic predisposition. With age, IDD progresses, leading to spondylosis, spondylarthrosis, herniated disc, spinal canal stenosis. One of the leading mechanisms in the development of IDD and chronic back pain is an imbalance between pro-inflammatory and anti-inflammatory cytokines. However, classical therapeutic strategies for correcting cytokine imbalance in IDD do not give the expected response in more than half of the cases. The purpose of this review is to update knowledge about new and promising therapeutic strategies based on the correction of the molecular mechanisms of cytokine imbalance in patients with IDD. This review demonstrates that knowledge of the molecular mechanisms of the imbalance between pro-inflammatory and anti-inflammatory cytokines may be a new key to finding more effective drugs for the treatment of IDD in the setting of acute and chronic inflammation.

Monotropein attenuates apoptosis and pyroptosis in chondrocytes and alleviates osteoarthritis progression in mice

BACKGROUND

Osteoarthritis (OA) is a chronic degenerative joint disease characterized by loss of joint function, which seriously reduces the quality of life of the elderly and imposes a heavy socioeconomic burden worldwide. Monotropein (MON), the main active ingredient of Morinda officinalis F.C. How, has exhibited therapeutic effects in different disease models. However, its potential effects on chondrocytes in an arthritic model remain unclear. This study aimed to evaluate the effects of MON in chondrocytes and a mouse model of OA, and explore the potential mechanisms.

MATERIALS AND METHODS

Murine primary chondrocytes were pretreated with 10 ng/ml interleukin (IL)-1β for 24 h to establish an in vitro model of OA, and then treated with different concentrations of MON (0, 25, 50 and 100 μM) for 24 h. The proliferation of the chondrocytes was assayed using ethynyl-deoxyuridine (EdU) staining. Immunofluorescence staining, western blotting and TUNEL staining were performed to assess the effects of MON on cartilage matrix degradation, apoptosis and pyroptosis. The mouse model of OA was constructed by surgical destabilization of the medial meniscus (DMM), and the animals were randomly divided into the sham-operated, OA and OA + MON groups. Following OA induction, the mice were given intraarticular injection of 100 μM MON or equal volume of normal saline twice a week for 8 weeks. The effects of MON on cartilage matrix degradation, apoptosis and pyroptosis were assessed as indicated.

RESULTS

MON significantly accelerated the proliferation of chondrocytes, and inhibited cartilage matrix degradation, apoptosis and pyroptosis in the IL-1β-stimulated cells by blocking the nuclear factor-kappa B (NF-κB) signaling pathway. In the mouse model as well, MON treatment alleviated OA progression and promoted cartilage repair by inhibiting cartilage matrix degradation, and chondrocyte apoptosis and pyroptosis through the inactivation of the NF-κB signaling pathway. Furthermore, the MON-treated arthritic mice exhibited better articular tissue morphology and lower OARSI scores.

CONCLUSIONS

MON alleviated OA progression by inhibiting cartilage matrix degradation, and the apoptosis and pyroptosis of chondrocytes via NF-κB pathway inactivation, and is a promising alternative for the treatment of OA.

Hederagenin Suppresses Inflammation and Cartilage Degradation to Ameliorate the Progression of Osteoarthritis: An In vivo and In vitro Study

Osteoarthritis (OA), a common degenerative joint disease, is characterized by the progressive degradation of articular cartilage and inflammation. Hederagenin (HE) is a pentacyclic triterpenoid saponin extracted from many herb plants. It has anti-inflammatory, anti-lipid peroxidative, anti-cancer, and neuroprotective activities. However, its effect on OA has not been investigated. Our study found that HE may be a potential anti-OA drug. In vitro, HE could suppress extracellular matrix (ECM) degradation via up-regulating aggrecan and Collagen II levels as well as downregulating MMPs and ADAMTS5 levels. It could also reduce proinflammatory and inflammatory cytokines or enzymes production, including TNF-α, IL-6, iNOS, COX-2, NO, and PGE₂. Besides, HE markedly reduced IL-1β-induced C28/I2 cell apoptosis and ROS accumulation. Mechanistically, HE exerted chondroprotective and anti-inflammatory effects by partly inhibiting JAK2/STAT3/MAPK signalling pathway and the crosstalk of the two pathways. Also, HE exhibited anti-apoptotic and anti-oxidative effect via targeting Keap1-Nrf2/HO-1/ROS/Bax/Bcl-2 axis. In vivo, HE significantly reduced monosodium iodoacetate (MIA) induced cartilage destruction of rats with a lower OARSI score and inflammatory cytokine levels, further demonstrating its protective effects in OA progression. These results suggest that HE is a potential compound for the development of drugs to treat OA.

Eugenol protects chondrocytes and articular cartilage by downregulating the JAK3/STAT4 signaling pathway

Osteoarthritis (OA) is a chronic degenerative bone and joint disease common in middle-aged and elderly people. Currently, there is no satisfactory pharmacological treatment. Eugenol is a phenolic compound that has been shown to exert biological anti-inflammatory, antioxidant, and antiapoptotic effects in multiple systems and organs of the human body. However, its therapeutic effect on OA is unclear. This study examined the effect of eugenol on OA using an anterior cruciate ligament transection (ACLT) model in mice and its related signaling pathways in interleukin-1β (IL-1β)-stimulated human chondrocytes. A certain concentration of eugenol inhibited the decrease in cell viability induced by IL-1β or carbonyl cyanide 3-chlorophenylhydrazone (CCCP). In vitro, eugenol effectively inhibited CCCP-induced chondrocyte apoptosis and mitochondrial membrane potential changes and inhibited the expressions of ADAMTS4 and MMP13 upregulated by IL-1β. In vivo, ACLT induced destruction of the articular cartilage and subchondral bone of the mouse tibial plateau, while eugenol effectively protected the cartilage and subchondral bone from such damage. At the same time, eugenol reduced the ACLT-induced upregulation of ADAMTS4 and MMP13 and the downregulation of type II collagen (COLII) and aggrecan in the mouse knee cartilage. Eugenol also inhibited the increased expression of cartilage metabolism signaling molecules such as C-telopeptides of COLII (CTX-II) in ACLT-induced mouse serum. Consistent with the specific changes in the messenger RNA chip, eugenol inhibited the phosphorylation of JAK3 and STAT4 induced by IL-1β. Together, these results suggest eugenol as an effective new drug for the prevention and treatment of OA.

Successful isolation of viable stem cells from cryopreserved microfragmented human adipose tissue from patients with knee osteoarthritis - a comparative study of isolation by tissue explant culture and enzymatic digestion

PURPOSE

To investigate if viable stem cells could be isolated and expanded from cryopreserved microfragmented adipose tissue (AT) harvested from patients with knee osteoarthritis.

METHODS

Microfragmented abdominal AT from knee osteoarthritis patients was cryopreserved at -80 °C in cryoprotectant-medium. The samples were thawed for stem cell isolation by tissue explant culture (TEC) and enzymatic digestion (ED), respectively. Viability, population doublings, and doubling time were assessed by trypan blue staining and flow cytometry. Cell type and senescence-associated β-galactosidase activity were analyzed by flow cytometry. Osteogenic and adipogenic differentiation was assessed quantitatively by Alizarin-Red-S and Oil-Red-O staining, respectively.

RESULTS

Microfragmented AT from 7 patients was cryopreserved for a period of 46-150 days (mean (SD) 115.9 days (44.3 days)). Viable stem cells were successfully recovered and expanded from all patients using both isolation methods with no significant difference in viable population doublings or doubling time from passage 1 to 3 (p > 0.05). Low levels of senescence-associated β-galactosidase activity was detected for both methods with no significant difference between TEC and ED (p = 0.17). Stemness was verified by stem cell surface markers and osteogenic and adipogenic differentiation performance. Adventitial stem cells (CD31^-CD34⁺CD45^-CD90⁺CD146^-), pericytes (CD31^-CD34^-CD45^-CD90⁺CD146⁺), transitional pericytes (CD31^-CD34⁺CD45^-CD90⁺CD146⁺), and CD271⁺ stem cells (CD31^-CD45^-CD90⁺CD271⁺) were identified using both methods. More pericytes were present when using TEC (25% (24%)) compared to ED (3% (2%)) at passage 4 (p = 0.04).

CONCLUSIONS

Viable stem cells can be isolated and expanded from cryopreserved microfragmented AT using both TEC and ED. TEC provides more clinically relevant pericytes than ED.

Silencing of IRF7 ameliorates osteoarthritis by inhibiting chondrocyte pyroptosis via targeting FGF21

Osteoarthritis (OA) is the most common joint disease which can lead to serious disability. Interferon regulatory factor 7 (IRF7) is a member of the interferon regulatory factor family. This study aimed to explore the function and potential mechanism of IRF7 in OA. Our results found that IRF7 was increased in LPS-stimulated C28/I2 chondrocytes and in OA mice established with medial menisco-tibial ligament (MMTL) transection. IRF7 silencing enhanced cell viability, reduced IL-18 and IL-1β levels and suppressed cell apoptosis. IRF7 knockdown decreased ROS and LDH levels, and inhibited pyroptosis in LPS-treated chondrocytes. IRF7 negatively regulated FGF21 expression. FGF21 overexpression alleviated pyroptosis in LPS-stimulated chondrocytes. Knockdown of IRF7 improved OA injury in mice. In conclusion, our study demonstrates that silencing of IRF7 alleviates OA by inhibiting chondrocyte pyroptosis via upregulation of FGF21.

Osteoarthritis year in review 2022: epidemiology & therapy

This 'Year in Review' provides a synopsis of key research themes and individual studies from the clinical osteoarthritis (OA) field, focused on epidemiology and therapy. The electronic database search for the review was adapted from the 2021 year in review search, to increase search specificity for relevant study designs, and was conducted in Medline, Embase and medRxiv (31^st March 2021 to 4^th March 2022). Following screening for eligibility, studies were grouped according to their key research design, including reviews, cohorts and randomised trials. 11 key themes emerged, including the importance of several comorbidities in predicting OA incidence and prevalence, surgical approaches that can reduce the risk of post-traumatic OA, the heterogenous but nevertheless relatively stable nature of OA subgroup trajectories, the paucity of robust studies particularly of surgery for OA and the very modest benefit of many therapies under evaluation in trials. A particular interest of the authors was to consider whether new studies are helping determine how to better ensure the right patient with OA is matched to the right treatment at the right time. There are several new studies developing improved predictive models through big data analytics and machine learning which show promise, need validation, and may support new approaches to stratified care.

Getting Cartilage Thickness Measurements Right: A Systematic Inter-Method Comparison Using MRI Data from the Osteoarthritis Initiative

OBJECTIVE

Magnetic resonance imaging is the standard imaging modality to assess articular cartilage. As the imaging surrogate of degenerative joint disease, cartilage thickness is commonly quantified after tissue segmentation. In lack of a standard method, this study systematically compared five methods for automatic cartilage thickness measurements across the knee joint and as a function of region and sub-region: 3D mesh normals (3D-MN), 3D nearest neighbors (3D-NN), 3D ray tracing (3D-RT), 2D centerline normals (2D-CN), and 2D surface normals (2D-SN).

DESIGN

Based on the manually segmented femoral and tibial cartilage of 507 human knee joints, mean cartilage thickness was computed for the entire femorotibial joint, 4 joint regions, and 20 subregions using these methods. Inter-method comparisons of mean cartilage thickness and computation times were performed by one-way analysis of variance (ANOVA), Bland-Altman analyses and Lin's concordance correlation coefficient (CCC).

RESULTS

Mean inter-method differences in cartilage thickness were significant in nearly all subregions (P < 0.001). By trend, mean differences were smallest between 3D-MN and 2D-SN in most (sub)regions, which is also reflected by highest quantitative inter-method agreement and CCCs. 3D-RT was prone to severe overestimation of up to 2.5 mm. 3D-MN, 3D-NN, and 2D-SN required mean processing times of ≤5.3 s per joint and were thus similarly efficient, whereas the time demand of 2D-CN and 3D-RT was much larger at 133 ± 29 and 351 ± 10 s per joint (P < 0.001).

CONCLUSIONS

In automatic cartilage thickness determination, quantification accuracy and computational burden are largely affected by the underlying method. Mesh and surface normals or nearest neighbor searches should be used because they accurately capture variable geometries while being time-efficient.

Factors associated with subjective knee joint stiffness in people with knee osteoarthritis: A systematic review

INTRODUCTION

Subjective knee stiffness is a common symptom in patients with knee osteoarthritis treated conservatively. However, the influencing factors or effects of knee joint stiffness are unknown. The aim of this study was to explore the factors associated with subjective knee stiffness in patients with knee osteoarthritis.

METHODS

The MEDLINE, Cochrane Central Register of Controlled Trials, EMBASE, Cumulative Index to Nursing and Allied Health Literature, Web of Science, and PEDro databases were searched in November 2021. Prospective or retrospective cohort studies were included. The methodological quality of the selected articles was assessed using the Scottish Intercollegiate Guidelines Network checklist.

RESULTS

Twenty out of 1943 screened articles were included in this systematic review. Eighteen and two studies were rated as having acceptable and low quality, respectively. All the included studies measured subjective knee stiffness using the Western Ontario and McMaster Universities Osteoarthritis Index. The main findings were that worse preoperative subjective knee stiffness was associated with worse pain, subjective knee stiffness, and patient satisfaction at 1 year after total knee arthroplasty. In addition, worse subjective knee stiffness was associated with future degenerative changes in the knee joint, such as joint space narrowing and osteophyte growth progression.

CONCLUSION

Subjective knee stiffness may be associated with the prognosis after total knee arthroplasty and degenerative changes in the knee joint. Early detection and treatment of knee stiffness could lead to a good prognosis after total knee arthroplasty and prevent the progression of degenerative changes in the knee joint.

ssDNA-Modified Gold Nanoparticles as a Tool to Detect miRNA Biomarkers in Osteoarthritis

Recently, miRNAs have been established as promising, specific biomarkers for the diagnosis of many diseases, including osteoarthritis. Herein, we report a ssDNA-based detection method for miRNAs implicated in osteoarthritis, specifically, miR-93 and miR-223. In this study, gold nanoparticles (AuNPs) were modified with oligonucleotide ssDNA to detect miRNAs circulating in the blood in healthy subjects and patients suffering from osteoarthritis. The detection method was based on the colorimetric and spectrophotometric assessment of biofunctionalized AuNPs upon interaction with the target and their subsequent aggregation. Results showed that these methods could be used to detect easily and rapidly miR-93 but not miR-223 in osteoarthritic patients, and they could potentially be used as a diagnostic tool for blood biomarkers. Visual-based detection as well as spectroscopic methods are simple, rapid, and label-free, due to which they can be used as a diagnostic tool.

Cationic micelles as nanocarriers for enhancing intra-cartilage drug penetration and retention

There is a tremendous unmet medical need for osteoarthritis (OA) treatment around the world, and pharmacological management is the most common option but presents a limited and short efficacy. Insufficient drug delivery to articular cartilage is the key cause. It is widely accepted that the complex structure of articular cartilage and the rapid clearance of joint liquids largely hinder drug penetration and retention in the cartilage. To address these obstacles, we designed and prepared a positively charged micellar system that can effectively deliver a model drug to the deep zone of the cartilage and prolong the drug retention time. In this work, a triblock copolymer composed of cationic poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) and poly(ε-caprolactone) (PCL), denoted as PDMAEMA-PCL-PDMAEMA, was synthesized. A triblock copolymer composed of brush poly[poly(ethylene glycol) methacrylate] (pPEGMA) and PCL, denoted as pPEGMA-PCL-pPEGMA, was prepared for comparison. The two types of triblock copolymers were self-assembled in an aqueous environment to form cationic and neutral micelles, respectively. A hydrophobic fluorescent dye as a model drug was loaded into micelle cores, and the dye-loaded micelles were evaluated for intra-cartilage penetration and retention using porcine knee cartilage explants. The PDMAEMA-PCL-PDMAEMA cationic micelles were found to significantly enhance the intra-cartilage penetration and retention capability due to the electrostatic interaction between the micelles and the negatively charged cartilage extracellular matrix. The confocal microscopy study showed that the cationic micelles could penetrate the full-thickness porcine cartilage explants (around 1.5 mm) within 24 hours. Up to 87% of the cationic micelles were taken up by porcine cartilage explants, and 71% of the absorbed micelles were retained in the tissue for at least 4 days. Although the pPEGMA-PCL-pPEGMA neutral micelles were able to penetrate the full-thickness cartilage, this type of micelle showed lower uptake (44%) and retention (44%) rates. This observation implied that the surface charge of micelles could play an important role in efficient intra-cartilage drug delivery. This study verified the feasibility and effectiveness of the PDMAEMA-PCL-PDMAEM cationic micelles in intra-cartilage drug delivery, showing that cationic micelles could be promising carriers for OA treatment.

Psychological comorbidities in osteoarthritis in Germany

Osteoarthritis is a degenerative joint disease associated with pain, loss of function and reduced quality of life. Concomitant psychological disorders can significantly influence treatment outcomes. Therefore, we aimed to answer the following research questions: (1) How has the incidence of primary coxarthrosis and gonarthrosis developed over the last decade? (2) How high is the prevalence of osteoarthritis patients with concomitant psychological diagnoses? (3) Which psychological comorbidities are most prevalent in coxarthrosis and gonarthrosis patients, respectively? For this cross-sectional study, a dataset provided by the Federal Statistical Office (Destatis) consisting of annual, Germany-wide ICD-10 diagnosis codes from 2009 to 2019 was analysed. Incidences of the codes "M16.1" and "M17.1", unilateral primary coxarthrosis and unilateral primary gonarthrosis, were quantified. Prevalence rates of secondary diagnoses of the chapter F of the ICD-10 were determined. Incidences were 230.7/100,000 inhabitants for coxarthrosis and 224.2/100,000 inhabitants for gonarthrosis. Patients with psychological comorbidities constituted 9.0% of coxarthrosis cases and 8.9% of gonarthrosis cases, respectively. Between 2009 through 2019, the proportion of patients with a concomitant "F" diagnoses of the ICD-10 increased by + 37.8% for coxarthrosis and by 17.9% for gonarthrosis. The most prevalent secondary diagnoses were affective disorders (F3), whereby numbers increased over the years. Increasing psychological comorbidities advocate for the implementation of screening tools, prevention strategies, interdisciplinary approaches and psychological support in the treatment of osteoarthritis.

Identification of chondrocyte subpopulations in osteoarthritis using single-cell sequencing analysis

Osteoarthritis (OA) is the most common joint disease. Previous studies were focused on general functions of chondrocyte population in OA without elucidating the existence of chondrocyte subpopulations. To investigate the heterogeneity of chondrocyte, here we conducted detailed analysis on the single-cell sequencing data of cartilage cells from OA patients. After quality control, unsupervised K-mean clustering identified seven different subpopulations of chondrocytes in OA. Those subpopulations of chondrocytes were nominated based on Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis: stress-metabolizing chondrocytes (cluster 1), rhythmic chondrocytes (cluster 2), apoptotic chondrocytes (cluster 3), matrix-synthesis-related chondrocytes (cluster 4), developmental chondrocytes (cluster 5), protein-synthesis-related chondrocytes (cluster 6 and 8), and osteogenesis chondrocytes (cluster 7). We further noticed that the stress-metabolizing chondrocytes (cluster 1) were dominant in early stages of cartilage damage with increased metabolic levels inhibiting cartilage tissue degeneration, while the matrix-synthesis-related chondrocytes (cluster 4) were mainly existed in the late stages of cartilage damage which reorganized collagen fibers with type III collagen disrupting the extracellular matrix and further cartilage damages. Besides, we identified genes NFKBIA and TUBB2B as potential markers for the stress-metabolizing chondrocytes and the matrix synthesis related chondrocytes, respectively. Our study identifies different chondrocyte subpopulations in OA, and highlights the potential different functions of chondrocyte subpopulations in the early versus late stages of cartilage damage.

Cyasterone inhibits IL-1β-mediated apoptosis and inflammation via the NF-κB and MAPK signaling pathways in rat chondrocytes and ameliorates osteoarthritisin vivo

Osteoarthritis is a prevalent global joint disease, which is characterized by inflammatory reaction and cartilage degradation. Cyasterone, a sterone derived from the roots of Cyathula officinalis Kuan, exerts protective effect against several inflammation-related diseases. However, its effect on osteoarthritis remains unclear. The current study was designed to investigate the potential anti-osteoarthritis activity of cyasterone. Primary chondrocytes isolated from rats induced by interleukin (IL)-1β and a rat model stimulated by monosodium iodoacetate (MIA) were used for in vitro and in vivo experiments, respectively. The results of in vitro experiments showed that cyasterone apparently counteracted chondrocyte apoptosis, increased the expression of collagen II and aggrecan, and restrained the production of the inflammatory factors inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), a disintegrin and metalloproteinase with thrombospondin motifs-5 (ADAMTS-5), metalloproteinase-3 (MMP-3), and metalloproteinase-13 (MMP-13) induced by IL-1β in chondrocytes. Furthermore, cyasterone ameliorated the inflammation and degenerative progression of osteoarthritis potentially by regulating the nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) pathways. For in vivo experiments, cyasterone significantly alleviated the inflammatory response and cartilage destruction of rats induced by monosodium iodoacetate, where dexamethasone was used as the positive control. Overall, this study laid a theoretical foundation for developing cyasterone as an effective agent for the alleviation of osteoarthritis.

Plantamajoside suppresses the activation of NF-κB and MAPK and ameliorates the development of osteoarthritis

Osteoarthritis (OA) is a common degenerative bone and joint disorder characterized by progressive cartilage degeneration and secondary synovial inflammation. It is a common chronic joint disorder that affects people of all ages (especially the old). Plantamajoside is a phenylpropanoside derived from plantain. It has a variety of biological properties, including antioxidant, anti-malignant cell proliferation, and anti-inflammatory properties. In this study, the latent mechanism of plantamajoside was explored by slowing the in-vivo and in-vitro progression of osteoarthritis. The results revealed that plantamajoside pre-conditioning inhibited IL-1β induced pro-inflammatory factors like COX-2, iNOS, IL-6, and TNF-α. Moreover, plantamajoside also reversed the IL-1 β mediated type II collagen and aggrecan degradation within the extracellular matrix (ECM). The protective effects of plantamajoside have been attributed to the inhibition of both MAPK and NF-κB pathways. Furthermore, our in-vivo research found that plantamajoside could slow the progression of OA in mice. Finally, all findings point to plantamajoside as a potential anti-OA therapeutic candidate.

Atraumatic Bone Marrow Edema Involving the Epiphyses

Bone marrow edema (BME)-like signal intensity involving the epiphyses of tubular bones represents a frequent magnetic resonance imaging finding associated with a wide spectrum of bone and joint disorders. It is important to distinguish this finding from cellular infiltration of bone marrow and to be aware of the differential diagnosis of underlying causes. With a general focus on the adult musculoskeletal system, this article reviews the pathophysiology, clinical presentation, histopathology, and imaging findings of nontraumatic conditions associated with epiphyseal BME-like signal intensity: transient bone marrow edema syndrome, subchondral insufficiency fracture, avascular necrosis, osteoarthritis, arthritis, and bone neoplasms.

Exploration of novel drug delivery systems in topical management of osteoarthritis

Osteoarthritis is one of the foremost disabling disorders in the world. There is no definitive treatment to prevent the progression of osteoarthritis. Hence, palliative treatment aims at minimizing pain, disability and improving function, performance and quality of life. Oral administration of nonsteroidal anti-inflammatory drug is associated with number of adverse effects and reduced therapeutic efficacy. Intra-articular injection has been the preferred route of drug administration. However, the clearance of drug from the arthritic site, risk of infections, cost and the pain associated with frequent injections make this route highly non-compliant to patients. Since osteoarthritis is a chronic condition which requires treatment for prolonged duration, there is an urgent need for another administration route which circumvents the hindrances linked with intra-articular route. Transdermal route across the skin locally at the osteoarthritis site could help in surpassing the disadvantages associated with intra-articular route. However, traversing skin barrier and reaching the chondrocytes with sufficient amount of the drug is extremely difficult. Nanocarrier-based approaches could hold an answer to the said shortcomings owing to their reduced size, targeting tunability and site specificity. In this article, we discuss the pathophysiology of osteoarthritis, molecular targets, and utilization of nanocarrier-based approaches to strategize the treatment of osteoarthritis in a new direction, i.e. topical delivery of nanocarriers in osteoarthritis.

Human osteoarthritis knee joint synovial fluids cleave and activate Proteinase-Activated Receptor (PAR) mediated signaling

Osteoarthritis (OA) is the most prevalent joint disorder with increasing worldwide incidence. Mechanistic insights into OA pathophysiology are evolving and there are currently no disease-modifying OA drugs. An increase in protease activity is linked to progressive degradation of the cartilage in OA. Proteases also trigger inflammation through a family of G protein-coupled receptors (GPCRs) called the Proteinase-Activated Receptors (PARs). PAR signaling can trigger pro-inflammatory responses and targeting PARs is proposed as a therapeutic approach in OA. Several enzymes can cleave the PAR N-terminus, but the endogenous protease activators of PARs in OA remain unclear. Here we characterized PAR activating enzymes in knee joint synovial fluids from OA patients and healthy donors using genetically encoded PAR biosensor expressing cells. Calcium signaling assays were performed to examine receptor activation. The class and type of enzymes cleaving the PARs was further characterized using protease inhibitors and fluorogenic substrates. We find that PAR1, PAR2 and PAR4 activating enzymes are present in knee joint synovial fluids from healthy controls and OA patients. Compared to healthy controls, PAR1 activating enzymes are elevated in OA synovial fluids while PAR4 activating enzyme levels are decreased. Using enzyme class and type selective inhibitors and fluorogenic substrates we find that multiple PAR activating enzymes are present in OA joint fluids and identify serine proteinases (thrombin and trypsin-like) and matrix metalloproteinases as the major classes of PAR activating enzymes in the OA synovial fluids. Synovial fluid driven increase in calcium signaling was significantly reduced in cells treated with PAR1 and PAR2 antagonists, but not in PAR4 antagonist treated cells. OA associated elevation of PAR1 cleavage suggests that targeting this receptor may be beneficial in the treatment of OA.

Association between serum 25-hydroxyvitamin D and osteoarthritis: A national population-based analysis of NHANES 2001-2018

Background

Previous studies have not provided a consensus on the effect of serum 25-hydroxyvitamin D [25(OH)D] on osteoarthritis (OA). We aimed to evaluate the association using a large, nationally representative sample.

Methods

The cross-sectional data were obtained from the 2001 to 2018 National Health and Nutrition Examination Survey (NHANES). Individuals aged ≥40 years who had information of serum 25(OH)D, self-report OA, and related covariates were included. Multivariable logistic regression analysis was employed to assess the association between serum 25(OH)D and osteoarthritis.

Results

Among the 21,334 participants included (weighted mean age, 56.9 years; 48.5% men), the proportion of participants with high serum 25(OH)D concentrations (≥100 nmol/L) increased significantly from 4.2% in 2001-2006 to 18.8% in 2013-2018. Higher serum 25(OH)D levels were associated with more osteoarthritis prevalence in fully adjusted model (odd ratio [OR] 1.25 [95% CI: 1.10, 1.43] for the 50-75 nmol/L group; OR 1.62 [95% CI: 1.42, 1.85] for the 75-100 nmol/L group; OR 1.91 [95% CI: 1.59, 2.30] for the ≥100 nmol/L group; with <50 nmol/L group as the reference) (p < 0.001 for trend). The association was consistent across several sensitivity analyses, including propensity score methods and excluding participants who had received vitamin D supplement. In subgroup analysis, the OR for the association increased significantly with body mass index (BMI) (BMI < 25 kg/m², 1.01 [95% CI: 1.04, 1.08]; BMI 25-30 kg/m², 1.05 [95% CI: 1.01, 1.08]; BMI ≥ 30 kg/m², 1.10 [95% CI: 1.06, 1.13]; p = 0.004 for interaction).

Conclusion

There was a positive correlation between serum 25(OH)D and osteoarthritis with a possible modification by BMI. Our finding raises concerns about the potential adverse effects of high serum 25(OH)D on osteoarthritis, particularly among obese individuals. More well-designed studies are still needed to validate our findings in future.

Hypoxia-Inducible Factor-1α Protects Against Intervertebral Disc Degeneration Through Antagonizing Mitochondrial Oxidative Stress

Intervertebral disc degeneration (IVDD) demonstrates a gradually increased incidence and has developed into a major health problem worldwide. The nucleus pulposus is characterized by the hypoxic and avascular environment, in which hypoxia-inducible factor-1α (HIF-1α) has an important role through its participation in extracellular matrix synthesis, energy metabolism, cellular adaptation to stresses and genesis. In this study, the effects of HIF-1α on mouse primary nucleus pulposus cells (MNPCs) exposed to TNF-α were observed, the potential mechanism was explored and a rabbit IVDD model was established to verify the protective role of HIF-1α on IVDD. In vitro results demonstrated that HIF-1α could attenuate the inflammation, apoptosis and mitochondrial dysfunction induced by TNF-α in MNPCs; promote cellular anabolism; and inhibit cellular catabolism. In vivo results demonstrated that after establishment of IVDD model in rabbit, disc height and IVD extracellular matrix were decreased in a time-dependent manner, MRI analysis showed a tendency for decreased T2 values in a time-dependent manner and supplementation of HIF-1α improved histological and imaginative IVDD while downregulation of HIF-1α exacerbated this degeneration. In summary, HIF-1α protected against IVDD, possibly through reducing ROS production in the mitochondria and consequent inhibition of inflammation, metabolism disorders and apoptosis of MNPCs, which provided a potential therapeutic instrument for the treatment of IVDD diseases.

Validación al español del instrumento Self-Administered Patient Satisfaction Scale (SAPS) para reemplazo total de cadera o de rodilla

Introducción: La satisfacción del paciente es un indicador importante al evaluar los resultados clínicos de un reemplazo total de cadera o rodilla. El objetivo de este estudio fue validar al idioma español el instrumento Self-Administered Patient Satisfaction Scale (SAPS) para reemplazo total de cadera o rodilla, y estudiar sus propiedades psicométricas. Materiales y Métodos: Se realizó un estudio de validación de corte transversal para evaluar el contenido, la consistencia interna y la validez de criterio de la SAPS. Se incluyó a 105 pacientes con reemplazo total de cadera o rodilla. La validez de criterio fue valorada con las escalas WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) y SF-36 (36-Item Short Form Survey). Resultados: Se analizó a 50 pacientes con reemplazo total de cadera y 55 con reemplazo total de rodilla y una mediana de seguimiento de 14 meses (rango intercuartílico, 11-19), con una edad de 71.3 ± 11.6 años; 73,3% (77) eran mujeres. El coeficiente alfa de Cronbach fue de 0,797 indicando una consistencia interna aceptable. La correlación entre las escalas SAPS y WOMAC fue moderada (coeficiente de Spearman 0,488; p <0,05), al igual que con el componente físico de la SF-36 (coeficiente de Spearman 0,525; p <0,05). Conclusión: La versión en español de la SAPS es una herramienta válida y confiable para medir el grado de satisfacción de los pacientes sometidos a reemplazo total de cadera o rodilla, tiene propiedades psicométricas similares a las de la escala original. Nivel de Evidencia: II

Bibliometric insights from publications on subchondral bone research in osteoarthritis

Background: The role of subchondral bone in the pathogenesis of osteoarthritis has received continuous attention worldwide. To date, no comprehensive bibliometric analysis of this topic has been carried out. The purpose of this study was to investigate the knowledge landscape, hot spots, and research trends in subchondral bone research through bibliometrics. Methods: Web of Science Core Collection database was used to collect articles and reviews on subchondral bone in osteoarthritis published between 2003 and 2022. CiteSpace, VOSviewer, Scimago Graphica, and a bibliometric online analysis platform (http://bibliometric.com/) were used to visualize the knowledge network of countries, institutions, authors, references, and keywords in this field. Both curve fitting and statistical plotting were performed using OriginPro, while correlation analysis was done using SPSS. Results: A total of 3,545 articles and reviews were included. The number of publications on subchondral bone showed an exponential growth trend. The US produced the most (980), followed by China (862) and the United Kingdom (364). Scientific output and gross domestic product were significantly correlated (r = .948, p < .001). The University of California System and Professor Pelletier Jean-Pierre were the most prolific institutions and influential authors, respectively. The most active and influential journal for subchondral bone research was Osteoarthritis and Cartilage. The majority of papers were financed by NSFC (474, 13.4%), followed by HHS (445, 12.6%), and NIH (438, 12.4%). In recent years, hot keywords have focused on the research of pathomechanisms (e.g., inflammation, apoptosis, pathogenesis, cartilage degeneration/repair, angiogenesis, TGF beta) and therapeutics (e.g., regeneration, stromal cell, mesenchymal stem cell). Conclusion: Subchondral bone research in osteoarthritis is flourishing. Current topics and next research trends would be centered on the pathomechanisms of cellular and molecular interactions in the subchondral bone microenvironment in the development of osteoarthritis and the exploration of targeted treatment medicines for the altered subchondral bone microenvironment.

Effect of Zingiber Cassumunar Roxb. Phonophoresis Versus Aqua Sonic Gel on Pain, Range of Motion, and Functional Disability in Patients With Osteoarthritis of Knee: A Randomized Controlled Trial

The aim of this trial was to collate, analyze, and compare the effectiveness of phonophoresis and ultrasound adjunct to Otago exercise program for pain, knee range of motion, and functional disability in patients with grades I and II of knee osteoarthritis. This is a single-blind randomized control study. A total of 52 patients with pre-diagnosed osteoarthritis on radiological investigation were included in the study. They were then randomly assigned into two groups: group A (n=26) received the experimental treatment, which included phonophoresis, and group B (n=26) subjects were treated with conventional physiotherapy. The interventions were given for six days/week for two weeks. Pain via the visual analog scale, knee range of motion via a goniometer, level of functional disability through the Western Ontario and McMaster Universities Osteoarthritis Index, and balance through the star excursion balance test were evaluated. Measurements of the outcome were taken prior to initiation of intervention and on the day of the last session, succeeding the treatment. Statistically, both the groups showed significant improvement in pain, range, dynamic balance, and functioning. Between the two groups, no clinically significant difference was present for balance, but the intergroup comparison for pain and functions was statistically and therefore clinically significant. Phonophoresis treatment was observed to be effective in treating pain in osteoarthritis. Combined Otago exercises and phonophoresis with modified gel can be used to achieve superior clinical results.

Bone marrow aspirate injection for osteoarthritis of the hip; A pilot study

Objectives

Bone marrow aspirate (BMA) intra-articular injection is a minimally invasive orthobiologic treatment option for osteoarthritis (OA). Hip OA affects a significant portion of the population and has a paucity of data surrounding orthobiologic treatments. The primary objective of this study was to delineate the clinical impact of bone marrow aspirate intra-articular injections on decreasing pain and improving function in patients with hip OA.

Methods

A single-center, retrospective analysis of thirty-one patients, aged 32 to 83 (62.4 ​± ​16.5), with Kellgren-Lawrence (KL) Hip OA grading of 2-4 (mean 2.9 ​± ​0.7), who underwent intra-articular bone marrow aspirate injection into the hip and were followed for twelve months. Evaluation was at baseline, 12 weeks, 6 months, and 12 months using the Numerical Rating Scale (NRS) for pain and the Hip Disability and Osteoarthritis Outcome Score Jr (HOOS-Jr) for function. The proportion of responders, as defined by a ≥50% reduction in NRS pain score, was assessed at 12 weeks, 6 months and 12 months.

Results

At 6 and 12 months follow-up, there was a statistically significant improvement in NRS scores (P ​< ​0.05). Stratifying by KL grade, subjects with KL grades 2 and 3 experienced statistically significant improvement in NRS scores at 6 and 12 months. Patients with KL grade 4 showed significant improvement in pain at 12 months. Forty-two percent of patients at 6 months and 61% at 12 months reported ≥50% reduction in pain. When stratifying by KL grade, 80% and 71% of KL2 and KL3 grades respectively were responders by 12 months. Patients experienced statistically significant improvement in HOOS-Jr scores at 6 and 12 months.

Conclusion

In patient with mild, moderate, and severe hip OA, BMA may be an alternative treatment that improves pain and function in patients for as long as 12 months. In addition, BMA may also be an effective, lower cost option to more expensive BMAC preparations.

3D Bioprinted Silk-Based In Vitro Osteochondral Model for Osteoarthritis Therapeutics

3D bioprinting of osteochondral tissue offers unique opportunities for enabling precise pharmacological interventions in osteoarthritis (OA). The current study investigates the screening potential of anti-inflammatory drugs using bioprinted inflamed human osteochondral units. The biomimetic hierarchical geometry is bioprinted using silk-based bioinks encapsulating pre-differentiated stem cells, creating an in vitro model. Inflammation is stimulated in the model, using tumor necrosis factor-alpha and Interleukin-1 beta pro-inflammatory cytokines. The resultant degeneration, akin to OA, is flagged by key markers like sulfated glycosaminoglycan, collagen, alkaline phosphatase, and downregulation of osteochondral transcript levels. In the next step, the screening of anti-inflammatory drugs is validated using celecoxib and rhein. Consequently, in the inflamed constructs, the initial upregulation of the key inflammatory mediators (nitric oxide, Prostaglandin E2), is subsequently downregulated, post-drug treatment. In addition, catabolic markers (matrix metalloproteinases and aggrecanase-1), indicative of hypertrophic and apoptosing chondrocytes, are significantly downregulated in the treatment groups; while the transcript and protein levels required for osteochondral health are attenuated. Therefore, the in vitro model mimicks the inflammation in the early stages of OA, and corroborates a potential high-throughput platform for screening novel anti-inflammatory drugs in OA therapeutics.