Pharmacotherapy for knee osteoarthritis: current and emerging therapies

Therapeutic Controlled Release Strategies for Human Osteoarthritis

Osteoarthritis is a progressive, irreversible debilitating whole joint disease that affects millions of people worldwide. Despite the availability of various options (non-pharmacological and pharmacological treatments and therapy, orthobiologics, and surgical interventions), none of them can definitively cure osteoarthritis in patients. Strategies based on the controlled release of therapeutic compounds via biocompatible materials may provide powerful tools to enhance the spatiotemporal delivery, expression, and activities of the candidate agents as a means to durably manage the pathological progression of osteoarthritis in the affected joints upon convenient intra-articular (injectable) delivery while reducing their clearance, dissemination, or side effects. The goal of this review is to describe the current knowledge and advancements of controlled release to treat osteoarthritis, from basic principles to applications in vivo using therapeutic recombinant molecules and drugs and more innovatively gene sequences, providing a degree of confidence to manage the disease in patients in a close future.

Recent advancements in microspheres mediated targeted delivery for therapeutic interventions in osteoarthritis

Osteoarthritis (OA), affecting around 240 million people globally is a major threat. Currently, available drugs only treat the symptoms of OA; they cannot reverse the disease's progression. The delivery of drugs to afflicted joints is challenging because of poor vasculature of articular cartilage results in their less bioavailability and quick elimination from the joints. Recently approved drugs such as KGN and IL-1 receptor antagonists also encounter challenges because of inadequate formulations. Therefore, microspheres could be a potential player for the intervention of OA owing to its excellent physicochemical properties. This review primarily focuses on microspheres of distinct biomaterials acting as cargo for drugs and biologicals via different delivery routes in the effective management of OA. Microspheres can improve the efficacy of therapeutics by targeting strategies at specific body locations. This review also highlights clinical trials conducted in the last few decades.

Immunoregulatory paracrine effect of mesenchymal stem cells and mechanism in the treatment of osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease caused by chronic inflammation that damages articular cartilage. At present, the treatment of OA includes drug therapy to relieve symptoms and joint replacement therapy for advanced OA. However, these palliatives cannot truly block the progression of the disease from the immunological pathogenesis of OA. In recent years, bone marrow mesenchymal stem cell (BMSC) transplantation has shown great potential in tissue engineering repair. In addition, many studies have shown that BMSC paracrine signals play an important role in the treatment of OA through immune regulation and suppressing inflammation. At present, the mechanism of inflammation-induced OA and the use of BMSC transplantation in joint repair have been reviewed, but the mechanism and significance of BMSC paracrine signals in the treatment of OA have not been fully reviewed. Therefore, this article focused on the latest research progress on the paracrine effects of BMSCs in the treatment of OA and the related mechanisms by which BMSCs secrete cytokines to inhibit the inflammatory response, regulate immune balance, and promote cell proliferation and differentiation. In addition, the application potential of BMSC-Exos as a new type of cell-free therapy for OA is described. This review aimed to provide systematic theoretical support for the clinical application of BMSC transplantation in the treatment of OA.

Pharmacotherapy for osteoarthritis-related pain: current and emerging therapies

INTRODUCTION

Osteoarthritis (OA) related pain has affected millions of people worldwide. However, the current pharmacological options for managing OA-related pain have not achieved a satisfactory effect.

AREAS COVERED

This narrative review provides an overview of the current and emerging drugs for OA-related pain. It covers the drugs' mechanism of action, safety, efficacy, and limitations. The National Library of Medicine (PubMed) database was primarily searched from 2000 to 2024.

EXPERT OPINION

Current treatment options are limited and suboptimal for OA pain management. Topical nonsteroidal anti-inflammatory drugs (NSAIDs) are the recognized and first-line treatment in the management of OA-related pain, and other drugs are inconsistent recommendations by guidelines. Emerging treatment options are promising for OA-related pain, including nerve growth factor (NGF) inhibitors, ion channel inhibitors, and calcitonin gene-related peptide (CGRP) antagonists. Besides, drugs repurposing from antidepressants and antiepileptic analgesics are shedding light on the management of OA-related pain. The management of OA-related pain is challenging as pain is heterogeneous and subjective. A more comprehensive strategy combined with non-pharmacological therapy needs to be considered, and tailored management options to individualized patients.

The role of YAP/TAZ on joint and arthritis

Osteoarthritis (OA) and rheumatoid arthritis (RA) are two common forms of arthritis with undefined etiology and pathogenesis. Yes-associated protein (YAP) and its homolog transcriptional coactivator with PDZ-binding motif (TAZ), which act as sensors for cellular mechanical and inflammatory cues, have been identified as crucial players in the regulation of joint homeostasis. Current studies also reveal a significant association between YAP/TAZ and the pathogenesis of OA and RA. The objective of this review is to elucidate the impact of YAP/TAZ on different joint tissues and to provide inspiration for further studying the potential therapeutic implications of YAP/TAZ on arthritis. Databases, such as PubMed, Cochran Library, and Embase, were searched for all available studies during the past two decades, with keywords "YAP," "TAZ," "OA," and "RA."

Omega-3 Supplementation and Its Effects on Osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease characterized by the destruction of the articular cartilage, resulting in a pro-inflammatory response. The progression of OA is multifactorial and is influenced by the underlying cause of inflammation, which includes but is not limited to trauma, metabolism, biology, comorbidities, and biomechanics. Although articular cartilage is the main tissue affected in osteoarthritis, the chronic inflammatory environment negatively influences the surrounding synovium, ligaments, and subchondral bone, further limiting their functional abilities and enhancing symptoms of OA. Treatment for osteoarthritis remains inconsistent due to the inability to determine the underlying mechanism of disease onset, severity of symptoms, and complicating comorbidities. In recent years, diet and nutritional supplements have gained interest regarding slowing the disease process, prevention, and treatment of OA. This is due to their anti-inflammatory properties, which result in a positive influence on pain, joint mobility, and cartilage formation. More specifically, omega-3 polyunsaturated fatty acids (PUFA) have demonstrated an influential role in the progression of OA, resulting in the reduction of cartilage destruction, inhibition of pro-inflammatory cytokine cascades, and production of oxylipins that promote anti-inflammatory pathways. The present review is focused on the assessment of evidence explaining the inflammatory processes of osteoarthritis and the influence of omega-3 supplementation to modulate the progression of osteoarthritis.

The metabolic characteristics and changes of chondrocytes in vivo and in vitro in osteoarthritis

Osteoarthritis (OA) is an intricate pathological condition that primarily affects the entire synovial joint, especially the hip, hand, and knee joints. This results in inflammation in the synovium and osteochondral injuries, ultimately causing functional limitations and joint dysfunction. The key mechanism responsible for maintaining articular cartilage function is chondrocyte metabolism, which involves energy generation through glycolysis, oxidative phosphorylation, and other metabolic pathways. Some studies have shown that chondrocytes in OA exhibit increased glycolytic activity, leading to elevated lactate production and decreased cartilage matrix synthesis. In OA cartilage, chondrocytes display alterations in mitochondrial activity, such as decreased ATP generation and increased oxidative stress, which can contribute to cartilage deterioration. Chondrocyte metabolism also involves anabolic processes for extracellular matrix substrate production and energy generation. During OA, chondrocytes undergo considerable metabolic changes in different aspects, leading to articular cartilage homeostasis deterioration. Numerous studies have been carried out to provide tangible therapies for OA by using various models in vivo and in vitro targeting chondrocyte metabolism, although there are still certain limitations. With growing evidence indicating the essential role of chondrocyte metabolism in disease etiology, this literature review explores the metabolic characteristics and changes of chondrocytes in the presence of OA, both in vivo and in vitro. To provide insight into the complex metabolic reprogramming crucial in chondrocytes during OA progression, we investigate the dynamic interaction between metabolic pathways, such as glycolysis, lipid metabolism, and mitochondrial function. In addition, this review highlights prospective future research directions for novel approaches to diagnosis and treatment. Adopting a multifaceted strategy, our review aims to offer a comprehensive understanding of the metabolic intricacies within chondrocytes in OA, with the ultimate goal of identifying therapeutic targets capable of modulating chondrocyte metabolism for the treatment of OA.

Microenvironmental interference with intra-articular stem cell regeneration influences the onset and progression of arthritis

Studies have indicated that the preservation of joint health and the facilitation of damage recovery are predominantly contingent upon the joint's microenvironment, including cell-cell interactions, the extracellular matrix's composition, and the existence of local growth factors. Mesenchymal stem cells (MSCs), which possess the capacity to self-renew and specialize in many directions, respond to cues from the microenvironment, and aid in the regeneration of bone and cartilage, are crucial to this process. Changes in the microenvironment (such as an increase in inflammatory mediators or the breakdown of the extracellular matrix) in the pathological context of arthritis might interfere with stem cell activation and reduce their ability to regenerate. This paper investigates the potential role of joint microenvironmental variables in promoting or inhibiting the development of arthritis by influencing stem cells' ability to regenerate. The present status of research on stem cell activity in the joint microenvironment is also outlined, and potential directions for developing new treatments for arthritis that make use of these intervention techniques to boost stem cell regenerative potential through altering the intra-articular environment are also investigated. This review's objectives are to investigate these processes, offer fresh perspectives, and offer a solid scientific foundation for the creation of arthritic treatment plans in the future.

CHMP5 attenuates osteoarthritis via inhibiting chondrocyte apoptosis and extracellular matrix degradation: involvement of NF-κB pathway

BACKGROUND

Osteoarthritis (OA), the most common joint disease, is linked with chondrocyte apoptosis and extracellular matrix (ECM) degradation. Charged multivesicular body protein 5 (CHMP5), a member of the multivesicular body, has been reported to serve as an anti-apoptotic protein to participate in leukemia development. However, the effects of CHMP5 on apoptosis and ECM degradation in OA remain unclear.

METHODS

In this study, quantitative proteomics was performed to analyze differential proteins between normal and OA patient articular cartilages. The OA mouse model was constructed by the destabilization of the medial meniscus (DMM). In vitro, interleukin-1 beta (IL-1β) was used to induce OA in human chondrocytes. CHMP5 overexpression and silencing vectors were created using an adenovirus system. The effects of CHMP5 on IL-1β-induced chondrocyte apoptosis were investigated by CCK-8, flow cytometry, and western blot. The effects on ECM degradation were examined by western blot and immunofluorescence. The potential mechanism was explored by western blot and Co-IP assays.

RESULTS

Downregulated CHMP5 was identified by proteomics in OA patient cartilages, which was verified in human and mouse articular cartilages. CHMP5 overexpression repressed cell apoptosis and ECM degradation in OA chondrocytes. However, silencing CHMP5 exacerbated OA chondrocyte apoptosis and ECM degradation. Furthermore, we found that the protective effect of CHMP5 against OA was involved in nuclear factor kappa B (NF-κB) signaling pathway.

CONCLUSIONS

This study demonstrated that CHMP5 repressed IL-1β-induced chondrocyte apoptosis and ECM degradation and blocked NF-κB activation. It was shown that CHMP5 might be a novel potential therapeutic target for OA in the future.

Injectable hydrogel with selenium nanoparticles delivery for sustained glutathione peroxidase activation and enhanced osteoarthritis therapeutics

Reactive oxygen burst in articular chondrocytes is a major contributor to osteoarthritis progression. Although selenium is indispensable role in the antioxidant process, the narrow therapeutic window, delicate toxicity margins, and lack of an efficient delivery system have hindered its translation to clinical applications. Herein, transcriptomic and biochemical analyses revealed that osteoarthritis was associated with selenium metabolic abnormality. A novel injectable hydrogel to deliver selenium nanoparticles (SeNPs) was proposed to intervene selenoprotein expression for osteoarthritis treatment. The hydrogels based on oxidized hyaluronic acid (OHA) cross-linked with hyaluronic acid-adipic acid dihydrazide (HA-ADH) was formulated to load SeNPs through a Schiff base reaction. The hydrogels were further incorporated with SeNPs, which exhibited minimal toxicity, mechanical properties, self-healing capability, and sustained drug release. Encapsulated with SeNPs, the hydrogels facilitated cartilage repair through synergetic effects of scavenging reactive oxygen species (ROS) and depressing apoptosis. Mechanistically, the hydrogel restored redox homeostasis by targeting glutathione peroxidase-1 (GPX1). Therapeutic outcomes of the SeNPs-laden hydrogel were demonstrated in an osteoarthritis rat model created by destabilization of the medial meniscus, including cartilage protection, subchondral bone sclerosis improvement, inflammation attenuation, and pain relief were demonstrated. These results highlight therapeutic potential of OHA/HA-ADH@SeNPs hydrogels, providing fundamental insights into remedying selenium imbalance for osteoarthritis biomaterial development.

Oxycodone-acetaminophen versus celecoxib for postoperative pain in knee osteoarthritis patients after total knee arthroplasty: a randomized, controlled study

PURPOSE

Oxycodone-acetaminophen is a synergic combination of semisynthetic opioid agonis and analgesic/antipyretic agent, which improves analgesic efficacy. This randomized, controlled study intended to evaluate the analgesic efficacy and tolerance of oxycodone-acetaminophen compared to celecoxib alone in post-total knee arthroplasty (TKA) knee osteoarthritis patients.

METHODS

One hundred and six knee osteoarthritis patients were randomized into oxycodone-acetaminophen group (N = 54) and celecoxib group (N = 52) at a 1:1 ratio. Each patient orally received oxycodone-acetaminophen (5 mg/325 mg, four times per day) or celecoxib (200 mg, twice per day) from 2 h to day (D) 3 after TKA; meanwhile, each patient received 2-day patient-controlled analgesia (PCA). The primary outcome was pain visual analog scale (VAS) score at rest; other assessments were the secondary outcomes.

RESULTS

Pain VAS scores at rest at D1, D2, D3, and pain VAS scores at flexion at D0.5, D1, D2, D3 were lower in oxycodone-acetaminophen group compared to celecoxib group (all P < 0.050). Besides, extra (P < 0.001) and total (P < 0.001) PCA consumption were declined in oxycodone-acetaminophen group compared with celecoxib group. Furthermore, patients' satisfaction score at D3 (P = 0.012) and D7 (P = 0.043) was higher in oxycodone-acetaminophen group versus celecoxib group. Hospital for special surgery knee score (HSS) at preoperation, M1, and M3 did not differ between the two groups (all P > 0.050). The incidences of all adverse events were not varied between oxycodone-acetaminophen and celecoxib groups (all P > 0.050).

CONCLUSION

Oxycodone-acetaminophen exerts superior analgesic efficacy, patients' satisfaction, and similar tolerance compared to celecoxib in post-TKA knee osteoarthritis patients.

What is the optimal dose of adipose-derived mesenchymal stem cells treatment for knee osteoarthritis? A conventional and network meta-analysis of randomized controlled trials

BACKGROUND

Despite increasing clinical investigations underscoring the efficacy and safety of adipose-derived mesenchymal stem cells (AD-MSCs) therapy in knee osteoarthritis (KOA), no article has recently reviewed the cell dosage. This study aimed to evaluate the efficacy and safety of varying doses of AD-MSCs in treating KOA using conventional and network meta-analysis.

METHODS

A search of databases in in Chinese and English was performed to identify randomized controlled trials (RCT) on MSCs for knee osteoarthritis from the inception date to May 1, 2022. This study mainly analyzed the efficacy of AD-MSCs in the treatment of KOA, and subgroup analysis was performed on the therapeutic effects of MSCs from different tissues at the same dose. We divided the different cell doses into low, moderate, and high groups, with the corresponding cell doses: (0-25)*10^6, (25-50)*10^6, and > 50*10^6 cells, respectively. We further analyzed the improvement of improvement of the Visual Analog Scale (VAS) and the Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores and the incidence of adverse events (AEs) after varied dosage injection.

RESULTS

A total of 16 literatures were included in this study, of which 8 literatures were about AD-MSCs. Conventional meta-analysis suggests that AD-MSCs can reduce pain and improve function in KOA patients, regardless of the cell doses, up to 12 months of follow-up. The network meta-analysis showed that intra-articular injection of AD-MSCs significantly improved pain and knee function scores in KOA patients compared with the control group at 3, 6, and 12 months. Among the three groups, the high-dose group had the best treatment effect, and the degree of joint pain and dysfunction indicators improved more significantly in the early stage. For adverse events, there was a dose-response trend that increased with increasing doses.

CONCLUSIONS

Both cell doses reduced pain and improved knee function in KOA patients. The effect surpassed in the high-dose group than in the moderate-dose, low-dose and control groups. However, adverse events also increase with the increase in dose, which should be carefully considered in clinical application, and the side effects still need to be paid attention to. Considering the limitations of this meta-analysis, future studies need to further explore the efficacy and safety of different doses of treatment, and carry out large sample, multi-center, randomized controlled trials to ensure the reliability and promotion value of the research results.

Prescription analgesic medication use among osteoarthritis patients

OBJECTIVE

Pharmacotherapy is the most common strategies to reduce pain for osteoarthritis (OA) patients. To analyze the trend and pattern of prescription analgesic medication use in American OA patients. Besides, our study also tried to figure out the demographic characteristics of opioid use among OA population which may helpful for managing the use of opioids.

METHODS

We included 2214 OA patients from 2007 to 2018. We extracted data from National Health and Nutrition Examination Survey (NHANES) database. We compared analgesics and anti-depression medications use by category between survey participants with OA and without.

RESULTS

For OA patients, NSAIDs, acetaminophen and gabapentinoid were the mostly highly used analgesics (10.2%, 9.0% and 8.9%, respectively). However, we also found that opioids use was very common in OA patients (7.7%) and the duration of opioids use was significantly long. In addition, the opioids use did not decrease from 2007 to 2018, while gabapentinoid increased rapidly from recent decade (From 5.0% to 12.1%). The common analgesic combination used by OA population was opioids with acetaminophen and gabapentinoid with selective serotonin reuptake inhibitors (SSRIs) (2.9% and 2.7%, respectively).

CONCLUSION

The use of gabapentinoid increased rapidly from recent decade, while opioids use did not decrease. The long-term excessive use of opioids was also a serious problem for OA pain control. More improvements such as focusing more on healthcare education and paying more attention on non-pharmacotherapy and the psychological situation of patients are needed.

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.

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.

Research Trends and Foci in Osteoarthritis Pain from 2012 to 2022: Bibliometric and Visualization Study

Background

Osteoarthritis (OA) is a painful and complex joint disease. The unique mechanisms and potential interventions of OA-induced pain have attracted researchers' attention in recent years. Bibliometric and visualization analysis is a comprehensive scientific method that integrates mathematical and statistical approaches to explore research priorities in a specific field. However, there are few studies on OA pain using bibliometric analysis.

Purpose

This study aimed to explore research trends and hotspots in OA pain research field, offer practical guidance to researchers looking for top-notch scholars/institutions/countries, and provide suggestions for journal submissions by analyzing the existing literature.

Methods

Raw data were extracted from Web of Science Core Collection. Microsoft Excel, the R package "bibliometrix", VOSviewer and CiteSpace software were used to analyze data and visualize relevant results.

Results

A total of 2493 articles were included for further bibliometric and visualization analysis. During the investigated period, 2021 with 343 publications was the most productive year. Fillingim, Roger B. and Bennell, Kim L. with 32 articles were the most productive authors. Most publications were from the USA (797 articles, 20,727 citations). Rehabilitation and treatment of OA pain were the hotspots in OA pain research area. The top-contributing journal was Osteoarthritis and Cartilage. Boston University (91 articles; 4050 citations) was the most active institution.

Conclusion

The total publications of OA pain generally increasing over the time in the last decade, and the escalating rate remained a high level. This is the first comprehensive bibliometric study in OA pain research field, and it will offer practical guidance to researchers in this field.

Efficacy of a proprietary combination of Tamarindus indica seeds and Curcuma longa rhizome extracts in osteoarthritis: a clinical investigation

Background

NXT15906F6 (TamaFlex™) is a proprietary blend containing standardized Tamarindus indica seeds and Curcuma longa rhizome extracts. Earlier, NXT15906F6 supplementation demonstrated reduced knee joint pain and improved musculoskeletal functions in healthy and knee osteoarthritis (KOA) subjects.

Objective

The present randomized, double-blind, placebo-controlled study was focused on validating the clinical efficacy of NXT15906F6 in a larger number of subjects with KOA.

Methods

Male and female subjects (age: 40-70 years; body mass index [BMI]: 20-29 kg/m²] were randomized into three groups receiving placebo (n = 50), NXT15906F6 (n = 50) or a blend of C. longa and Boswellia serrata extracts (CLBS) (n = 50). Subjects consumed 250 mg NXT15906F6, 1,000 mg CLBS or a matched placebo daily after breakfast over a period of 30 consecutive days. The primary efficacy outcome was the improvement in total Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, and the secondary efficacy measures included various tests on joint pain and musculoskeletal functions and evaluations ofserum high-sensitivity C-reactive protein (hs-CRP) and a cartilage degradation marker, C-terminal telopeptide of type II collagen in urine (uCTX-II).

Results

NXT15906F6 significantly (P < 0.001) reduced the WOMAC scores and improved musculoskeletal function scores in the participants as compared with baseline and placebo. NXT15906F6 participants reduced knee pain and improved musculoskeletal functions as early as day 5 of supplementation. In contrast, CLBS supplementation failed to show early efficacies in pain and functional scores, except for 30s-CST and primary knee flexion. The NXT1506F6-supplemented participants significantly reduced serum hs-CRP and uCTX-II levels from baseline and as compared with the placebo. Both supplementations did not alter the subjects' clinical chemistry, hematology, and vital parameters.

Conclusion

The anti-inflammatory botanical composition NXT15906F6 supplementation mitigated joint pain and improved musculoskeletal functions and joint motility in KOA subjects. This botanical composition was also well-tolerated by the volunteers.

Latest insights in disease-modifying osteoarthritis drugs development

Osteoarthritis (OA) is a prevalent and severely debilitating disease with an unmet medical need. In order to alleviate OA symptoms or prevent structural progression of OA, new drugs, particularly disease-modifying osteoarthritis drugs (DMOADs), are required. Several drugs have been reported to attenuate cartilage loss or reduce subchondral bone lesions in OA and thus potentially be DMOADs. Most biologics (including interleukin-1 (IL-1) and tumor necrosis factor (TNF) inhibitors), sprifermin, and bisphosphonates failed to yield satisfactory results when treating OA. OA clinical heterogeneity is one of the primary reasons for the failure of these clinical trials, which can require different therapeutic approaches based on different phenotypes. This review describes the latest insights into the development of DMOADs. We summarize in this review the efficacy and safety profiles of various DMOADs targeting cartilage, synovitis, and subchondral bone endotypes in phase 2 and 3 clinical trials. To conclude, we summarize the reasons for clinical trial failures in OA and suggest possible solutions.

Evaluation of the effectiveness of topical oily solution containing frankincense extract in the treatment of knee osteoarthritis: a randomized, double-blind, placebo-controlled clinical trial

OBJECTIVE

Pharmacological treatments of osteoarthritis (OA) have several side effects. Boswellia serrata resin (frankincense) is rich in boswellic acids that have antioxidant and anti-inflammatory effects; though, their oral bioavailability is low. The aim of this study was evaluation of the clinical effectiveness of frankincense extract in the treatment of knee OA. In a randomized double-blind placebo-controlled clinical trial, eligible patients with knee OA were randomly divided into two groups of drug (33 patients) and control (37 patients), to use oily solution of frankincense extract or placebo, respectively, on the involved knee three times daily for four weeks. WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index), VAS (visual analogue scale; for pain severity), and PGA (patient global assessment) scores were determined before and after intervention.

RESULTS

For all evaluated outcome variables, there was a significant decrease from baseline in both groups (P < 0.001 for all). Furthermore, the end-of-intervention values for all parameters were significantly lower in drug group than placebo group (P < 0.001 for all), showing more effectiveness of drug compared to placebo.

CONCLUSION

Topical oily solution containing enriched extract of boswellic acids could decrease pain severity and improve the function in patients with knee OA. Trial Registration Trial registration number: IRCT20150721023282N14. Trial registration date: September 20, 2020. The study was retrospectively registered in Iranian Registry of Clinical Trials (IRCT).

Role of geniculate artery embolization in the treatment of knee pain secondary to osteoarthritis

Background

Osteoarthritis (OA) is a leading cause of chronic knee pain and disability with a reported prevalence of 25–30% of the population. Knee OA has traditionally been thought as a degenerative disease only related to chronic repetitive injury “wear and tear” mechanism, yet it is now considered as a much more complex disease of inflammatory nature induced by cytokines and inflammatory mediators through abnormal neo-vascularization (angiogenesis). The rational of geniculate artery embolization (GAE) is based on the hypothesis that suggesting a direct relationship between the abnormal angiogenesis and the chronic knee pain. As a novel treatment option based on occlusion of these abnormal neo-vessels via geniculate artery embolization, we postulated that such a mechanism will relieve pain and improve the quality of life. GAE has been previously approved as a safe and effective treatment in cases of post-knee arthroplasty hemarthrosis.

Purpose

To evaluate the feasibility, safety, and efficacy of geniculate artery embolization for OA-related knee pain.

Materials and methods

Sixteen patients with knee pain secondary to chronic OA refractory to conservative therapies for at least 6 months and not yet fit for total knee replacement were enrolled in a prospective single arm interventional study. GAE was performed using 150–300 μm microspheres. Patients were assessed and followed up using the visual analogue scale (VAS) for pain and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) for the overall knee function at baseline and at 1 week, 1, 3, and 6 months post-embolization.

Results

A total 16 patients presented by knee pain secondary to chronic OA were enrolled. All of them showed a remarkable improvement in the VAS and WOMAC scores, with better clinical outcome after GAE. Pre- versus post-embolization ± MDs in VAS score from 8.38 ± 0.81 (baseline) to 2.88 ± 1.54 after 6 months (post-embolization) equivalent to 66.66% improvement. There was also a satisfactory improvement in the WOMAC scores, with ± MDs drop from 77.94 ± 10.62 (baseline) to 49.69 ± 15.43 (post-embolization) equivalent to 37.41% improvement. No severe or life-threatening complications were reported.

Conclusions

GAE holds promise as an effective minimally invasive procedure for the treatment of knee pain secondary to OA and could be introduced as a safe technique with no serious complications.

In Vitro Anti-Inflammatory and Antioxidant Activities of pH-Responsive Resveratrol-Urocanic Acid Nano-Assemblies

Inflammatory environments provide vital biochemical stimuli (i.e., oxidative stress, pH, and enzymes) for triggered drug delivery in a controlled manner. Inflammation alters the local pH within the affected tissues. As a result, pH-sensitive nanomaterials can be used to effectively target drugs to the site of inflammation. Herein, we designed pH-sensitive nanoparticles in which resveratrol (an anti-inflammatory and antioxidant compound (RES)) and urocanic acid (UA) were complexed with a pH-sensitive moiety using an emulsion method. These RES-UA NPs were characterized by transmission electron microscopy, dynamic light scattering, zeta potential, and FT-IR spectroscopy. The anti-inflammatory and antioxidant activities of the RES-UA NPs were assessed in RAW 264.7 macrophages. The NPs were circular in shape and ranged in size from 106 to 180 nm. The RES-UA NPs suppressed the mRNA expression of the pro-inflammatory molecules inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages in a concentration-dependent manner. Incubation of LPS-stimulated macrophages with RES-UA NPs reduced the generation of reactive oxygen species (ROS) in a concentration-dependent manner. These results suggest that pH-responsive RES-UA NPs can be used to decrease ROS generation and inflammation.

A nomogram based on radiological features of MRI for predicting the risk of severe pain in patients with osteoarthritis of the knee

Methods

This study aimed to develop and validate a nomogram for predicting the risk of severe pain in patients with knee osteoarthritis. A total of 150 patients with knee osteoarthritis were enrolled from our hospital, and nomogram was established through a validation cohort (n = 150). An internal validation cohort (n = 64) was applied to validate the model.

Results

Eight important variables were identified using the Least absolute shrinkage and selection operator (LASSO) and then a nomogram was developed by Logistics regression analysis. The accuracy of the nomogram was determined based on the C-index, calibration plots, and Receiver Operating Characteristic (ROC) curves. Decision curves were plotted to assess the benefits of the nomogram in clinical decision-making. Several variables were employed to predict severe pain in knee osteoarthritis, including sex, age, height, body mass index (BMI), affected side, Kellgren-Lawrance (K-L) degree, pain during walking, pain going up and down stairs, pain sitting or lying down, pain standing, pain sleeping, cartilage score, Bone marrow lesion (BML) score, synovitis score, patellofemoral synovitis, bone wear score, patellofemoral bone wear, and bone wear scores. The LASSO regression results showed that BMI, affected side, duration of knee osteoarthritis, meniscus score, meniscus displacement, BML score, synovitis score, and bone wear score were the most significant risk factors predicting severe pain.

Conclusions

Based on the eight factors, a nomogram model was developed. The C-index of the model was 0.892 (95% CI: 0.839-0.945), and the C-index of the internal validation was 0.822 (95% CI: 0.722-0.922). Analysis of the ROC curve of the nomogram showed that the nomogram had high accuracy in predicting the occurrence of severe pain [Area Under the Curve (AUC) = 0.892] in patients with knee osteoarthritis (KOA). The calibration curves showed that the prediction model was highly consistent. Decision curve analysis (DCA) showed a higher net benefit for decision-making using the developed nomogram, especially in the >0.1 and <0.86 threshold probability intervals. These findings demonstrate that the nomogram can predict patient prognosis and guide personalized treatment.

A pH-responsive metal-organic framework for the co-delivery of HIF-2α siRNA and curcumin for enhanced therapy of osteoarthritis

The occurrence of osteoarthritis (OA) is highly correlated with the reduction of joint lubrication performance, in which persistent excessive inflammation and irreversible destruction of cartilage dominate the mechanism. The inadequate response to monotherapy methods, suboptimal efficacy caused by undesirable bioavailability, short retention, and lack of stimulus-responsiveness, are few unresolved issues. Herein, we report a pH-responsive metal-organic framework (MOF), namely, MIL-101-NH₂, for the co-delivery of anti-inflammatory drug curcumin (CCM) and small interfering RNA (siRNA) for hypoxia inducible factor (HIF-2α). CCM and siRNA were loaded via encapsulation and surface coordination ability of MIL-101-NH₂. Our vitro tests showed that MIL-101-NH₂ protected siRNA from nuclease degradation by lysosomal escape. The pH-responsive MIL-101-NH₂ gradually collapsed in an acidic OA microenvironment to release the CCM payloads to down-regulate the level of pro-inflammatory cytokines, and to release the siRNA payloads to cleave the target HIF-2α mRNA for gene-silencing therapy, ultimately exhibiting the synergetic therapeutic efficacy by silencing HIF-2α genes accompanied by inhibiting the inflammation response and cartilage degeneration of OA. The hybrid material reported herein exhibited promising potential performance for OA therapy as supported by both in vitro and in vivo studies and may offer an efficacious therapeutic strategy for OA utilizing MOFs as host materials.

Enhanced osteoarthritis therapy by nanoengineered mesenchymal stem cells using biomimetic CuS nanoparticles loaded with plasmid DNA encoding TGF-β1

Mesenchymal stem cells (MSCs) therapy shows the potential benefits to relieve clinical symptoms of osteoarthritis (OA), but it is uncertain if it can repair articular cartilage lesions — the main pathology of OA. Here, we prepared biomimetic cupper sulfide@phosphatidylcholine (CuS@PC) nanoparticles (NPs) loaded with plasmid DNA (pDNA) encoding transforming growth factor-beta 1 (TGF-β1) to engineer MSCs for enhanced OA therapy via cartilage regeneration. We found that the NPs not only promoted cell proliferation and migration, but also presented a higher pDNA transfection efficiency relative to commercial transfection reagent lipofectamine 3000. The resultant CuS/TGF-β1@PC NP-engineered MSCs (termed CTP-MSCs) were better than pure MSCs in terms of chondrogenic gene expression, glycosaminoglycan deposition and type II collagen formation, favoring cartilage repair. Further, CTP-MSCs inhibited extracellular matrix degradation in interleukin-1β-induced chondrocytes. Consequently, intraarticular administration of CTP-MSCs significantly enhanced the repair of damaged cartilage, whereas pure MSCs exhibited very limited effects on cartilage regeneration in destabilization of the medial meniscus (DMM) surgical instability mice. Hence, this work provides a new strategy to overcome the limitation of current stem cell therapy in OA treatment through developing more effective nanoengineered MSCs.

•

Biomimetic CuS nanoparticles (NPs) loaded with TGF-β1 pDNA are prepared for nanoengineering of MSCs.

•

CuS/TGF-β1@PC NPs are more efficient than commercial transfection agent in terms of pDNA transfection.

•

The NP-engineered CTP-MSCs exhibit enhanced migration, chondrogenesis and inhibition of ECM degradation.

•

CTP-MSCs effectively treat osteoarthritis (OA) mice models via cartilage regeneration.

Combination of mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP) in the treatment of knee osteoarthritis: a meta-analysis of randomised controlled trials

OBJECTIVES

The purpose of this meta-analysis was to investigate the efficacy and safety of mesenchymal stem cells (MSCs) combined with platelet-rich plasma (PRP) in the treatment of knee osteoarthritis (KOA).

DESIGN

Systematic review and meta-analysis.

PARTICIPANTS

Patients with KOA.

INTERVENTIONS

Use of MSCs+PRP.

PRIMARY AND SECONDARY OUTCOMES

Visual Analogue Scale (VAS) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, Knee Injury and Osteoarthritis Outcome Score (KOOS) and adverse reactions.

DATA SOURCES

PubMed, Cochrane Library, Embase and China National Knowledge Infrastructure were searched from inception to 15 July 2021.

MEASURES

The OR or weighted mean difference (WMD) of relevant outcome indicators was calculated. Study quality was evaluated using the risk-of-bias assessment tool version 2.0. Heterogeneity among studies was evaluated by calculating I². If I²＜50%, a fixed-effect model was applied; conversely, if I² ≥50%, a random-effect model was applied.

RESULTS

Six controlled clinical trials with 493 cases were included. The meta-analysis results showed that in terms of the VAS score 3 months after treatment, MSCs+PRP had no significant effect on the reduction of the VAS score in patients with KOA compared with the control (p=0.09), hyaluronic acid (HA) (p=0.15) or PRP alone (p=0.07). MSCs+PRP was more effective in reducing the VAS score at 6 and 12 months after treatment than the control (WMD=-0.55, 95% CI -0.87 to -0.22, p<0.001), HA (WMD=-1.20, 95% CI -2.28 to -0.13, p=0.03) or PRP alone (WMD=-0.54, 95% CI -0.89 to -0.18, p=0.003). Regarding the decrease in the total WOMAC score at 3 and 6 months after treatment, MSCs+PRP showed better clinical efficacy than the control or HA alone (p<0.01). Compared with the control, MSCs+PRP exhibited no significant difference in reducing the total WOMAC score 12 months after treatment (p=0.39). There was no significant difference between MSCs+PRP and the control in terms of improvement of the KOOS 12 months after treatment (p=0.16). Compared with MSCs alone, MSCs+PRP exhibited no significant difference in the incidence of adverse reactions (p=0.22) 12 months after treatment.

CONCLUSIONS

Treatment with MSCs+PRP showed good clinical efficacy in improving pain and joint function in patients with KOA. Compared with MSCs alone, there was no significant difference in the incidence of adverse reactions with MSCs+PRP.

PROSPERO REGISTRATION NUMBER

CRD 42021275830.

Targeting Inflammation and Regeneration: Scaffolds, Extracellular Vesicles, and Nanotechnologies as Cell-Free Dual-Target Therapeutic Strategies

Osteoarthritis (OA) affects over 250 million people worldwide and despite various existing treatment strategies still has no cure. It is a multifactorial disease characterized by cartilage loss and low-grade synovial inflammation. Focusing on these two targets together could be the key to developing currently missing disease-modifying OA drugs (DMOADs). This review aims to discuss the latest cell-free techniques applied in cartilage tissue regeneration, since they can provide a more controllable approach to inflammation management than the cell-based ones. Scaffolds, extracellular vesicles, and nanocarriers can be used to suppress inflammation, but they can also act as immunomodulatory agents. This is consistent with the latest tissue engineering paradigm, postulating a moderate, controllable inflammatory reaction to be beneficial for tissue remodeling and successful regeneration.

Chondroitin sulfate modified chitosan nanoparticles as an efficient and targeted gene delivery vehicle to chondrocytes

Conventional treatments for osteoarthritis (OA), including drug delivery and tissue engineering approaches, could not offer a high yield of cartilage repair due to the compact and exclusive structure of cartilage. Targeted and high-efficiency delivery of gene sequences is necessary to rebalance the lost homeostatic properties of the cartilage in OA. Herein, we synthesized chitosan (CH)-chondroitin sulfate (CS) nanoparticles (NPs) as a platform for delivering gene sequences. These new nanoparticles benefit from two natural polymers that minimize the toxicity, and the presence of CS can be in favor of targeted delivery. The CAG-GFP plasmid was used as a gene sequence model, and the nanoparticles could successfully encapsulate approximately all of them in their structure. Loaded nanoparticles were characterized in terms of morphology, size, zeta potential, the efficiency of encapsulation and, DNA release pattern. Cell viability and uptake of new nanoparticles were compared to the chitosan nanoparticles and Lipofectamine. After substituting TPP with CS, NPs exhibited a significant decrease in size. In addition, there was little difference in zeta potential between nanoparticles. Furthermore, a tremendous increase in plasmid uptake and cell viability was observed by CH-CS NPs compared to CH-TPP NPs and Lipofectamine. In the final stage, the knockdown level of MMP13 was evaluated with real-time RT-PCR for confirming the potential uptake of CH-CS NPs. The results revealed cellular uptake of siRNA loaded NPs and effective knockdown of MMP13 in chondrocytes. In conclusion, CH-CS nanoparticles can be considered as a candidate for gene therapy purposes in cartilage diseases.

Calycosin mitigates chondrocyte inflammation and apoptosis by inhibiting the PI3K/AKT and NF-κB pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Shaoyao Gancao Decoction (SG-Tang), originated from the Treatise on Febrile Diseases, is often used to treat OA pain symptoms. Whereas its efficacy has been verified by several clinical studies, the underlying mechanism remained unclear. Network pharmacology and UPLC-QTOF-MS analysis found that calycosin could be regarded as the active components of SG-Tang in treating OA. However, the effect of calycosin on cartilage destruction and the pathogenesis of OA are not known. Therefore, we evaluated the benefits of calycosin for OA and revealed the underlying mechanisms.

AIM OF STUDY

Using network pharmacology, UPLC-QTOF-MS analysis and experiments, the active components of SG-Tang were analyzed to explore their potential therapeutic mechanism in OA.

MATERIALS AND METHODS

The components of SG-Tang were detected by UPLC-QTOF-MS, and the possible active components and mechanism of SG-Tang in the treatment of OA were screened by network pharmacology. The OA mouse model was constructed by DMM. In total, 30 mice were randomly divided into three groups: Sham, DMM, and DMM + Calycosin. H&E, safranin O/fast green staining and the OARSI scores were used to evaluate joint injury in mice. In addition, OA models were established using chondrocytes treated with 10 ng/mL IL-1β. Treatment groups were treated with 100, 200 or 400 μM calycosin. CCK-8 assay was used for assessing the cytotoxic effects of calycosin. TUNEL staining and Western blotting were used to detect chondrocyte apoptosis. In addition, PI3K/Akt and NF-κB signaling pathway-related markers and cartilage matrix-related indicators were also detected.

RESULTS

In vivo studies showed that calycosin inhibited IL-1β-induced IL-6 and TNF-α production, as well as iNOS and COX-2 expression. Meanwhile, calycosin could inhibit IL-1β-induced degradation of cartilage matrix, including downregulation of MMP3, MMP-13, collagen II and aggrecan. NF-κB and PI3K/AKT were also inhibited by calycosin in OA chondrocytes. Furthermore, calycosin inhibited IL-1β-induced apoptosis in mouse chondrocytes. In a mouse model of OA, our results suggest that calycosin has a chondroprotective effect.

CONCLUSIONS

According to this study, calycosin may act as a protective agent against OA by inhibiting the PI3K/AKT and NF-κB pathways. Furthermore, this study suggested that calycosin is a potential candidate for the treatment of OA.

Clinical efficacy and safety of the combination of mesenchymal stem cells and scaffolds in the treatment of knee osteoarthritis: Protocol for systematic review and meta-analysis

BACKGROUND

Mesenchymal stem cells (MSCs) injection combined scaffolds for knee osteoarthritis (OA) is a relatively new treatment for knee OA and has not yet gained popularity. So, the effectiveness, safety is worthy to be explored. We performed a protocol for systematic review and meta-analysis to evaluate the efficacy and safety of the combination of MSCs and scaffolds in the treatment of knee OA.

METHODS

A literature search was performed in October 2022 without restriction to regions, publication types or languages. The primary sources were the electronic databases of PubMed, EMBASE, Cochrane Library, Web of Science and the ClinicalTrials.gov. Risk of bias was assessed using the Cochrane Collaboration's risk of bias tool for randomized controlled trials. Statistical analyses were performed utilizing Review Manager 5 (The Nordic Cochrane Center, Copenhagen, Denmark).

RESULTS

Visual analog scale score, Western Ontario and McMaster Universities Osteoarthritis Index, Lysholm knee scale and adverse events will be assessed.

CONCLUSION

The systematic review will provide evidence to assess the effectiveness and safety of MSCs combined scaffolds for the treatment of knee OA.

Physical therapy as a promising treatment for osteoarthritis: A narrative review

Osteoarthritis (OA) is the most prevalent joint disease and a leading cause of disability in older adults. With an increasing population ageing and obesity, OA is becoming even more prevalent than it was in previous decades. Evidence indicates that OA is caused by the breakdown of joint tissues from mechanical loading and inflammation, but the deeper underlying mechanism of OA pathogenesis remains unclear, hindering efforts to prevent and treat this disease. Pharmacological treatments are mostly related to relieving symptoms, and there is no drug for radical cure. However, compelling evidence suggests that regular practice of resistance exercise may prevent and control the development of several musculoskeletal chronic diseases including OA, which may result in improved quality of life of the patients. In this review, we introduced the current understanding of the mechanism and clinical treatments of OA pathogenesis. We also reviewed the recent study of physical therapy in the treatment of skeletal system disorders, especially in OA. Finally, we discuss the present challenges and promising advantages of physical therapy in OA treatment.

Placebo Response to Oral Administration in Osteoarthritis Clinical Trials and Its Associated Factors: A Model-Based Meta-analysis

Importance

In osteoarthritis (OA) clinical trials, a placebo is often used as control. Therefore, a thorough understanding of the placebo response is important for guiding drug development in OA.

Objective

To develop an oral placebo response model for OA.

Data Sources

PubMed, EMBASE, and Cochrane Library databases were searched systematically from January 1, 1991, to July 2, 2022.

Study Selection

Randomized double-blind placebo-controlled trials of patients with primary OA were included. The interventions and placebo were administered orally. A total of 3032 trials were identified; of these, 130 (4.3%) met the inclusion criteria.

Data Extraction and Synthesis

Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, dosage form of the placebo, sample size, proportion of patients who previously used nonsteroidal anti-inflammatory drugs, publication year, intervention categories, Kellgren-Lawrence grades, proportion of White patients, duration of pain, funding source, and risk of bias were extracted. A model-based meta-analysis was used to evaluate the time course of the placebo response in OA treatment and estimate the influencing factors. For subgroup analyses, a meta-analysis with a random-effects model was used to summarize the typical values of the model parameters and their SEs.

Main Outcomes and Measures

The primary end point was the time course of the oral placebo response on the WOMAC pain, stiffness, and function subscale scores.

Results

The 130 trials selected for analysis included 12 673 participants (mean age, 59.9 years; 68.9% women). The baseline scores of WOMAC pain, stiffness, and function subscales were found to be significantly associated with the placebo response. The placebo response reached 90% of its maximum response between 5 and 7 weeks. The placebo responses on the WOMAC subscales were also associated with the sample size, proportion of patients who had previously used nonsteroidal anti-inflammatory drugs, intervention drugs, and publication year.

Conclusions and Relevance

In this study, an oral placebo response model of OA was developed that may quantitatively describe the placebo response at different baseline levels of symptoms. The findings may provide valuable references for future clinical trial design and decision-making.

Patient characteristics, pain treatment patterns, and incidence of total joint replacement in a US population with osteoarthritis

BACKGROUND

Currently available medications for chronic osteoarthritis pain are only moderately effective, and their use is limited in many patients because of serious adverse effects and contraindications. The primary surgical option for osteoarthritis is total joint replacement (TJR). The objectives of this study were to describe the treatment history of patients with osteoarthritis receiving prescription pain medications and/or intra-articular corticosteroid injections, and to estimate the incidence of TJR in these patients.

METHODS

This retrospective, multicenter, cohort study utilized health plan administrative claims data (January 1, 2013, through December 31, 2019) of adult patients with osteoarthritis in the Innovation in Medical Evidence Development and Surveillance Distributed Database, a subset of the US FDA Sentinel Distributed Database. Patients were analyzed in two cohorts: those with prevalent use of "any pain medication" (prescription non-steroidal anti-inflammatory drugs [NSAIDs], opioids, and/or intra-articular corticosteroid injections) using only the first qualifying dispensing (index date); and those with prevalent use of "each specific pain medication class" with all qualifying treatment episodes identified.

RESULTS

Among 1 992 670 prevalent users of "any pain medication", pain medications prescribed on the index date were NSAIDs (596 624 [29.9%] patients), opioids (1 161 806 [58.3%]), and intra-articular corticosteroids (323 459 [16.2%]). Further, 92 026 patients received multiple pain medications on the index date, including 71 632 (3.6%) receiving both NSAIDs and opioids. Altogether, 20.6% of patients used an NSAID at any time following an opioid index dispensing and 17.2% used an opioid following an NSAID index dispensing. The TJR incidence rates per 100 person-years (95% confidence interval [CI]) were 3.21 (95% CI: 3.20-3.23) in the "any pain medication" user cohort, and among those receiving "each specific pain medication class" were NSAIDs, 4.63 (95% CI: 4.58-4.67); opioids, 7.45 (95% CI: 7.40-7.49); and intra-articular corticosteroids, 8.05 (95% CI: 7.97-8.13).

CONCLUSIONS

In patients treated with prescription medications for osteoarthritis pain, opioids were more commonly prescribed at index than NSAIDs and intra-articular corticosteroid injections. Of the pain medication classes examined, the incidence of TJR was highest in patients receiving intra-articular corticosteroids and lowest in patients receiving NSAIDs.

XMU-MP-1 attenuates osteoarthritis via inhibiting cartilage degradation and chondrocyte apoptosis

Osteoarthritis (OA) is the most prevalent type of degenerative joint disease; it is reported to be associated with inflammatory responses, chondrocyte apoptosis, and cartilage degeneration. XMU-MP-1 is a selective MST1/2 inhibitor which activates the downstream effector YAP and promotes cell growth. It has displayed excellent benefits in mouse intestinal repair, as well as liver repair and regeneration. However, the effects of XMU-MP-1 on OA remain unclear. In this study, we investigated the therapeutic role of XMU-MP-1 on interleukin-1β (IL-1β)-induced inflammation in mice chondrocytes and the destabilization of the medial meniscus surgery (DMM)-induced OA model. In chondrocytes, treatment with XMU-MP-1 elevated the matrix metalloproteinases (Mmp3, Mmp13) and decreased the extracellular matrix (Col2, Acan) induced by IL-1β. Moreover, XMU-MP-1 strongly inhibited IL-1β-induced chondrocyte apoptosis and significantly promoted chondrocyte proliferation. Furthermore, XMU-MP-1 demonstrated a protective and therapeutic influence on the mouse OA model. These findings indicate that XMU-MP-1 may have a protective effect on cartilage degradation and may be a new potential therapeutic option for OA.

Research on electroacupuncture parameters for knee osteoarthritis based on data mining

Background

Knee osteoarthritis, a common degenerative joint disease, has been widely treated by electroacupuncture in recent years. However, there are too many parameters of the treatment currently, resulting in various applications in clinical practice. This study aims to summarize the optimal stimulation parameters of electroacupuncture for knee osteoarthritis in clinical studies by applying data mining techniques.

Methods

Four databases including Pubmed, Cochrane Library, Embase, and Web of Science were searched for clinical studies on electroacupuncture treating knee osteoarthritis from 2012 to 2021. A database was established by Microsoft Excel 2020 and analyzed by R Version 4.1.1.

Results

Forty-six articles were included according to the established criteria. The most used electroacupuncture stimulation parameters were 0.30 mm × 40 mm needle, continuous wave, low frequency of current (mainly 2 Hz), stimulation duration for 30 min per treatment, and frequency of treatment for once a day. Eighteen acupoints were mentioned and the most used ones include Dubi (ST35), Liangqiu (ST34), Neixiyan (EX-LE4), Xuehai (SP10), Yanglingquan (GB34), and Yinlingquan (SP9), and those most generally used acupoints are closely arranged on the Stomach Channel of Foot Yangming. Cluster analysis showed two groups, one for obligatory acupoints and one for adjunctive ones. The association analysis showed the most supported acupoint pair was Liangqiu (ST34) and Xuehai (SP10).

Conclusions

Continuous wave, low frequency of current (2 Hz), 30-min stimulation, and local acupoint selection are frequently used for electroacupuncture treating knee osteoarthritis. Due to the limitations of this study, further research and more standardized, multi-centered, and large-sample clinical trials should be conducted to provide more convincing evidence.

Omega-3 Fatty Acids for the Management of Osteoarthritis: A Narrative Review

Osteoarthritis (OA) is a disease which results in degeneration of cartilage within joints and affects approximately 13.6% of adults over 20 years of age in Canada and the United States of America. OA is characterized by a state of low-grade inflammation which leads to a greater state of cellular catabolism disrupting the homeostasis of cartilage synthesis and degradation. Omega-3 polyunsaturated fatty acids (PUFAs) have been postulated as a potential therapeutic treatment option for individuals with OA. Omega-3 PUFAs are recognized for their anti-inflammatory properties, which could be beneficial in the context of OA to moderate pro-inflammatory markers and cartilage loss. The purpose of this narrative review is to outline recent pre-clinical and clinical evidence for the use of omega-3 in the management of OA.

The efficacy and safety of Jinwu Gutong capsule in the treatment of knee osteoarthritis: A meta-analysis of randomized controlled trials

ETHNOPHARMACOLOGICAL RELEVANCE

The Jinwu Gutong (JWGT) capsule is a Chinese patent medicine that is widely used in the treatment of knee osteoarthritis (KOA) and osteoporosis in China and is considered to have the potential for good clinical efficacy.

AIM OF THE STUDY

The purpose of this study was to systematically evaluate the clinical efficacy and safety of JWGT in the treatment of KOA.

MATERIALS AND METHODS

We searched the China National Knowledge Infrastructure (CNKI), Wanfang, SinoMed, PubMed, Embase and Cochrane Library databases to identify clinical trials that explore the use of JWGT only or JWGT combined with Western drugs (JWGT group) compared with the use of conventional Western drugs (Western drugs group) for the treatment of KOA. The clinical trials, that were retrieved from each database from the inception of the database to December 2021, were screened. We used the risk of bias assessment tool recommended by Cochrane to evaluate the quality of the included literature and RevMan 5.3 software for data analysis.

RESULTS

A total of 17 clinical randomized controlled trials (RCTs) were included in this study, with a total of 1930 participants, including 1015 people in the experimental group and 915 people in the control group. The results of the meta-analysis showed that the JWGT group exhibited better efficacy than the Western drug group with respect to WOMAC score (WMD = -6.25, 95% CI = -8.09 to -4.41, P < 0.001), VAS score (WMD = -1.36, 95% CI = -2.17 to -0.55, P = 0.001), KSS score (WMD = 23.01, 95% CI = 21.42 to 24.59, P < 0.001), IL-6 (SMD = -3.30, 95% CI = -4.84 to -1.76, P < 0.001), TNF-α (SMD = -1.70, 95% CI = -2.02 to -1.38, P < 0.001). The effective rate (OR = 2.56, 95% CI = 1.83 to 3.57, P < 0.001) and incidence of adverse reactions was significantly lower in the JWGT group than in the control group (OR = 0.13, 95% CI = 0.07 to 0.21, P < 0.001). Subgroup analysis showed that JWGT + NSAIDs had more advantages in regard to efficacy (OR = 2.05, 95% CI = 1.35 to 3.12, P < 0.001), and reducing adverse reactions (OR = 0.10, 95% CI = 0.06 to 0.18, P < 0.001), VAS score (WMD = -1.00, 95% CI = -1.93 to -0.07, P = 0.04), KSS score (WMD = 17.39, 95% CI = 15.39 to 19.39, P < 0.001), WOMAC score (WMD = -2.84, 95% CI = -10.75 to 5.08, P < 0.001), IL-6 (SMD = -1.42, 95% CI = -2.08 to -0.75, P < 0.001) and TNF-α (SMD = -1.68, 95% CI = -1.93 to -1.43, P < 0.001) than NSAIDs alone. Compared with hyaluronic acid (HA) alone, JWGT + HA had better clinical efficacy (OR = 3.08, 95% CI = 1.48 to 6.40, P < 0.001). Compared with glucosamine (GS) alone, JWGT + GS significantly reduced the Lequesne index score (WMD = -0.53, 95% CI = -0.85 to -0.21, P = 0.001) and the serum TNF-α level (SMD = -1.68, 95% CI = -1.93 to -1.43, P < 0.001), but it had no significant advantage in reducing the serum IL-6 level (SMD = -4.53, 95% CI = -10.13 to 1.07, P = 0.11).

CONCLUSION

JWGT is considered effective and safe in the treatment of KOA and is worthy of clinical application. In addition, the application of JWGT combined with NSAIDs, HA or GS can significantly improve the clinical efficacy of the latter agents in KOA treatment.

Saikosaponin D Inhibited IL-1β Induced ATDC 5 Chondrocytes Apoptosis In Vitro and Delayed Articular Cartilage Degeneration in OA Model Mice In Vivo

Osteoarthritis (OA) is the most common joint disease in the elderly, characterized by cartilage degradation and proliferation of subchondral bone. The pathogenesis of OA involves a variety of inflammatory mediators, including nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor (TNF)-α, and interleukin (IL)-1β. From the molecular mechanism, the nuclear factor-erythroid 2-related factor (Nrf2)/heme oxygenase-1 (HO-1) pathway and the expression of ROS regulated the production of the above inflammatory mediators. Saikosaponin D (SSD), which is an active ingredient isolated from Bupleurum, has various biological functions. In this study, IL-1β was used as a pro-inflammatory factor to create an in vitro OA model. According to the results of high-density culture, qPCR, ROS measurement, Western blot, and immunofluorescence, SSD activated the Nrf2/HO-1/ROS axis, inhibited the production of inflammatory mediators, and protected against ECM destruction. The DMM mouse model was used as a model of OA in mice. From the results of safranin O/fast green staining, hematoxylin–eosin staining, tartrate-resistant acid phosphatase (TRAP) staining, and OARSI scores, SSD protected against the mice knee articular cartilage degeneration and reduced the number of osteoclasts in the subchondral bone. Experimental results found that SSD suppressed IL-1β–induced differentiated ATDC 5 chondrocytes apoptosis via the Nrf2/HO-1/ROS axis in vitro. SSD delayed the progression of OA in DMMs model mice in vivo. Therefore, SSD has the potential to become a drug for clinical treatment of OA.

Alterations of the White Matter in Patients With Knee Osteoarthritis: A Diffusion Tensor Imaging Study With Tract-Based Spatial Statistics

Background

Functional and structural alterations in the gray matter have been observed in patients with knee osteoarthritis (KOA). However, little is known about white matter changes in KOA. Here, we evaluated fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) to investigate potential alterations in the white matter of patients with KOA.

Methods

A total of 166 patients with KOA, along with 88 age- and sex-matched healthy controls were recruited and underwent brain magnetic resonance imaging (MRI). Diffusion tensor imaging (DTI) data were collected and analyzed using tract-based spatial statistics (TBSS). Statistical significances were determined at p < 0.05 and were corrected by the threshold-free cluster enhancement (TFCE) method. Then, we evaluated potential correlations between FA, MD, AD, RD values and disease duration, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, and visual analog scale (VAS) scores.

Results

FA values for the body of corpus callosum, splenium of corpus callosum, bilateral superior longitudinal fasciculus, cingulum, bilateral superior corona radiata, and right posterior corona radiata were significantly higher in patients with KOA than in healthy controls (p < 0.05, TFCE corrected). Compared with healthy controls, patients with KOA also had significantly lower MD, AD, and RD values of the genu of corpus callosum, body of corpus callosum, splenium of corpus callosum, corona radiata, right posterior thalamic radiation, superior longitudinal fasciculus, and middle cerebellar peduncle (p < 0.05, TFCE corrected). Negative correlations were detected between WOMAC scores and AD values for the body of the corpus callosum and the splenium of the corpus callosum (p < 0.05, FDR corrected).

Conclusion

Patients with KOA exhibited extensive white matter alterations in sensorimotor and pain-related regions. Longitudinal observation studies on the causation between abnormalities in the white matter tracts and KOA is needed in the future.

Cationic nanocarrier of rhein based on hydrophobic ion pairing approach as intra-articular targeted regenerative therapy for osteoarthritis

Cartilage deterioration is the hallmark of osteoarthritis (OA). Rapid clearance of intra-articularly injected drugs and inherent cartilage barrier properties represent enormous challenges facing the effective local OA therapy. Rhein (RH), a dihydroxy-anthraquinone acid molecule, possess a potential chondroprotective effect. However, RH suffers from poor oral bioavailability besides its gastrointestinal side effects. Herein, for the first time, we exploited cationic carriers to target anionic cartilage matrix to create a RH-reservoir within the cartilage matrix, improving RH therapeutic efficacy with reduced side effects. Firstly, we improved RH lipophilic characteristics employing hydrophobic ion pairing (HIP) to be efficiently loaded within lipid nanoparticles with slow-release properties. RH-HIP integrated solid lipid nanoparticles (RH-SLNs) rapidly penetrated through cartilage tissue and lasted for 3 weeks into healthy and arthritic rat joints. Furthermore, RH-SLNs significantly inhibited inflammatory response, oxidative stress and cartilage deterioration in MIA-arthritic rats. In conclusion, intra-articular cationic RH-SLNs represented a meaningful step towards OA therapy.

1,25-Dihydroxyvitamin D Inhibits Osteoarthritis by Modulating Interaction Between Vitamin D Receptor and NLRP3 in Macrophages

Background

Osteoarthritis (OA) is the most prevalent chronic joint disease globally. Loss of extracellular matrix (ECM) by chondrocytes is a classic feature of OA. Inflammatory cytokines, such as interleukin-1β (IL-1β) and interleukin-18 (IL-18), secreted mainly by macrophages, promote expression of matrix degrading proteins and further aggravate progression of OA. 1,25-dihydroxyvitamin D (1,25VD) modulates inflammation thus exerting protective effects on cartilage tissue. However, the underlying mechanisms of 1,25VD activity have not been fully elucidated.

Methods

The destabilization of the medial meniscus (DMM)-induced mice model of OA was established to investigate the protective effects of 1,25VD by micro-CT and Safranin-O and Fast Green staining. And the co-culture system between THP-1 cells and primary chondrocytes was constructed to explore the effects of vitamin D receptor (VDR) and 1,25VD on chondrogenic proliferation, apoptosis, and migration. The immunofluorescence staining and Western blot analysis were used to detect the expressions of ECM proteins and matrix degradation-associated proteases. Enzyme-linked immunosorbent assay (ELISA) was used to examine the expression levels of inflammatory cytokines.

Results

The findings of the study showed that 1,25VD prevented cartilage degeneration and osteophyte formation by inhibiting secretion of inflammatory cytokines in OA mice model. These protective effects were exerted through the vitamin D receptor (VDR). Further studies showed that 1,25VD increased ubiquitination level of NLRP3 by binding to VDR, resulting in decrease in IL-1β and IL-18 secretion. These findings indicate that 1,25VD binds to VDR thus preventing chondrogenic ECM degradation by modulating macrophage NLRP3 activation and secretion of inflammatory cytokines, thus alleviating OA progression.

Conclusion

Here, our study suggests that 1,25VD, targeting to VDR, prevents chondrogenic ECM degradation through regulating macrophage NLRP3 activation and inflammatory cytokines secretion, thereby alleviating OA. These findings provide information on a novel molecular mechanism for application of 1,25VD as OA therapy.

The effect of cartilage decellularized extracellular matrix-chitosan compound on treating knee osteoarthritis in rats

Knee osteoarthritis (KOA) refers to a common disease in orthopaedics, whereas effective treatments have been rarely developed. As indicated from existing studies, chondrocyte death, extracellular matrix degradation and subchondral bone injury are recognized as the pathological basis of KOA. The present study aimed to determine the therapeutic effect of decellularized extracellular matrix-chitosan (dECM-CS) compound on KOA. In this study, rat knee cartilage was decellularized, and a satisfactory decellularized extracellular matrix was developed. As suggested from the in vitro experiments, the rat chondrocytes co-cultured with allogeneic dECM grew effectively. According to the results of the alamar blue detection, dECM did not adversely affect the viability of rat chondrocytes, and dECM could up-regulate the genes related to the cartilage synthesis and metabolism. As reported from the animal experiments, dECM-CS compound could protect cartilage, alleviate knee joint pain in rats, significantly delay the progress of KOA in rats, and achieve high drug safety. In brief, dECM-CS compound shows a good therapeutic effect on KOA.

Osteoarthritic infrapatellar fat pad aggravates cartilage degradation via activation of p38MAPK and ERK1/2 pathways

OBJECTIVE

This study aimed to investigate the biochemical effects of osteoarthritic infrapatellar fat pad (IPFP) on cartilage and the underlying mechanisms.

METHODS

Human IPFP and articular cartilage were collected from end-stage osteoarthritis (OA) patients during total knee arthroplasty. IPFP-derived fat-conditioned medium (FCM) was used to stimulate human primary chondrocytes and cartilage explants. Functional effect of osteoarthritic IPFP was explored in human primary chondrocytes and articular cartilage in vitro and ex vivo. Activation of relative pathways and its effects on chondrocytes were assessed through immunoblotting and inhibition experiments, respectively. Neutralization test was performed to identify the main factors and their associated pathways responsible for the effects of IPFP.

RESULTS

Osteoarthritic IPFP-derived FCM significantly induced extracellular matrix (ECM) degradation in both human primary chondrocytes and cartilage explants. Several pathways, such as NF-κB, mTORC1, p38MAPK, JNK, and ERK1/2 signaling, were significantly activated in human chondrocytes with osteoarthritic IPFP-derived FCM stimulation. Interestingly, inhibition of p38MAPK and ERK1/2 signaling pathway could alleviate the detrimental effects of FCM on chondrocytes, while inhibition of other signaling pathways had no similar results. In addition, IL-1β and TNF-α instead of IL-6 in osteoarthritic IPFP-derived FCM played key roles in cartilage degradation via activating p38MAPK rather than ERK1/2 signaling pathway.

CONCLUSION

Osteoarthritic IPFP induces the degradation and inflammation of cartilage via activation of p38MAPK and ERK1/2 pathways, in which IL-1β and TNF-α act as the key factors. Our study suggests that modulating the effects of IPFP on cartilage may be a promising strategy for knee OA intervention.

Treating osteoarthritis pain: mechanisms of action of acetaminophen, nonsteroidal anti-inflammatory drugs, opioids, and nerve growth factor antibodies

Osteoarthritis (OA) is a common difficult-to-treat condition where the goal, in the absence of disease-modifying treatments, is to alleviate symptoms such as pain and loss of function. Acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs), and opioids are common pharmacologic treatments for OA. Antibodies directed against nerve growth factor (NGF-Abs) are a new class of agents under clinical investigation for the treatment of OA. This narrative review describes (and uses schematics to visualize) nociceptive signaling, chronification of pain, and the mechanisms of action (MOAs) of these different analgesics in the context of OA-related pain pathophysiology. Further, the varying levels of efficacy and safety of these agents observed in patients with OA is examined, based on an overview of published clinical data and/or treatment guidelines (when available), in the context of differences in their MOAs.

Osteoarthritis-Related Knee Pain Treated With Genicular Artery Embolization: A Systematic Review and Meta-analysis

BACKGROUND

Genicular artery embolization (GAE) is an innovative technique that has been investigated as a supplementary treatment method for chronic pain secondary to knee osteoarthritis (OA).

PURPOSE

To evaluate the current evidence on the effectiveness and safety of GAE for OA-related knee pain.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic literature search was conducted in the PubMed, Web of Science, EMBASE, and Scopus databases to identify studies related to knee OA treated with GAE. Treatment agents were categorized as Embozene, imipenem/cilastatin, resorbable microspheres, and polyvinyl alcohol. The main outcomes were the mean difference (MD) in pre- and postembolization pain based on the visual analog scale (VAS) or the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores as well as changes in the need for pain medication. Random- and fixed-effects models were applied for data analysis.

RESULTS

Of 379 initially inspected publications, 11 (N = 225 patients; 268 knees) were included in the final review. The quality of the studies was fair in 8 and poor in 3-categorized according to the National Institutes of Health quality assessment tool. Overall, 119, 72, 13, and 21 patients were treated with imipenem/cilastatin, Embozene, resorbable microspheres, and polyvinyl alcohol, respectively. Symptomatic improvement was reported in all studies. The pooled effect size, characterized by MD, showed a significant improvement in the VAS and WOMAC pain scores, with better functional status after GAE. Pre- versus postembolization MDs in VAS scores ranged from 32 within the first week to 58 after a 2-year follow-up (equivalent to 54% and 80% improvement, respectively). There was a similar trend in the overall WOMAC scores, with MDs ranging from 28.4 to 36.8 (about 58% and 85% improvement, respectively). GAE resulted in a decreased need for pain medication for knee OA, with a 27%, 65%, and 73% decline in the number of patients who used opioids, nonsteroidal anti-inflammatory drugs, and intra-articular hyaluronic acid injection, respectively (P < .00001 for all). No significant difference between embolic agents was seen with regard to post-GAE pain reduction. No severe or life-threatening complications were reported.

CONCLUSION

OA treated by GAE using different embolic particles can be considered generally safe, with good efficacy and no reported serious complications.

S-Allylcysteine Inhibits Chondrocyte Inflammation to Reduce Human Osteoarthritis via Targeting RAGE, TLR4, JNK and Nrf2 Signaling: Comparison with Colchicine

Discovery of new pharmacological agents is needed to control the progression of osteoarthritis (OA) characterized by progressive joint cartilage damage. Human OA chondrocyte cultures (OAC) were either applied to S-Allyl cysteine (SAC), a sulfur-containing amino acid derivative, or colchicine, an ancient anti-inflammatory therapeutic, for 24 hours. SAC or colchicine did not change viability at 1 nM-10 µM but inhibited p-JNK/pan-JNK. While SAC seems to be more effective, both agents inhibited reactive oxygen species (ROS), 3-nitrotyrosine (3-NT), lipid-hydroperoxides (LPO), advanced lipoxidation end-products (ALEs as 4-hydroxy-2-nonenal, HNE) and advanced glycation end-products (AGEs), and increased glutathione-peroxidase (GPx) and type-II-collagen (COL2). IL-1β, IL-6 and osteopontin (OPN) were more strongly inhibited by SAC than in colchicine. In contrast, TNF-α was inhibited only by SAC, and COX2 only by colchicine. Casp-1/ICE, GM-CSF, receptor for advanced glycation end-products (RAGE) and toll-like receptors (TLR4) were inhibited by both agents, but bone morphogenetic protein 7 (BMP7) was partially inhibited by SAC while induced by colchicine. The nuclear factor erythroid 2-related factor 2 (Nrf2) was induced by SAC; in contrast it was inhibited by colchicine. Although exerting opposite effects on TNF-α, COX2, BMP7 and Nrf2, SAC and colchicine exhibit anti-osteoarthritic properties in OAC by modulating redox sensitive inflammatory signaling.