Recent advances in the treatment of osteoarthritis

Molecular signaling pathways in osteoarthritis and biomaterials for cartilage regeneration: a review

Osteoarthritis is a prevalent degenerative joint disease characterized by cartilage degradation, synovial inflammation, and subchondral bone alterations, leading to chronic pain and joint dysfunction. Conventional treatments provide symptomatic relief but fail to halt disease progression. Recent advancements in biomaterials, molecular signaling modulation, and gene-editing technologies offer promising therapeutic strategies. This review explores key molecular pathways implicated in osteoarthritis, including fibroblast growth factor, phosphoinositide 3-kinase/Akt, and bone morphogenetic protein signaling, highlighting their roles in chondrocyte survival, extracellular matrix remodeling, and inflammation. Biomaterial-based interventions such as hydrogels, nanoparticles, and chitosan-based scaffolds have demonstrated potential in enhancing cartilage regeneration and targeted drug delivery. Furthermore, CRISPR/Cas9 gene editing holds promise in modifying osteoarthritis-related genes to restore cartilage integrity. The integration of regenerative biomaterials with precision medicine and molecular therapies represents a novel approach for mitigating osteoarthritis progression. Future research should focus on optimizing biomaterial properties, refining gene-editing efficiency, and developing personalized therapeutic strategies. The convergence of bioengineering and molecular science offers new hope for improving joint function and patient quality of life in osteoarthritis management.

The inflammatory endotype in osteoarthritis: Reflections from the 2024 OARSI clinical trials symposium (CTS) with a special emphasis on feasibility for clinical development

Objective

The inflammatory endotype is arguably one of the most well-established endotype in osteoarthritis (OA). While endotyping holds promise for advancing drug development, numerous potential challenges must be considered, addressed and resolved before successful clinical outcomes can be achieved.

Design

Since 2017, the Osteoarthritis Research Society International (OARSI) has hosted the Clinical Trials Symposium (CTS). Each year, OARSI and the CTS steering committee encourage discussions on selected topics among a broad range of stakeholders, including regulators, drug developers, clinicians, clinical researchers, biomarker specialists, and basic scientists, with the aim of advancing drug development in the OA field.

Results

This report highlights the ongoing tension between academia's "blue ocean" strategy and the feasibility-driven approach of drug developers, all within the context of scientific efforts to find effective solutions. Understanding the needs, goals, constraints, and opportunities of all involved stakeholders is crucial for defining optimal drug development strategies for OA.

Conclusion

A multidisciplinary, collaborative approach is essential for developing effective OA treatments, balancing scientific discovery with regulatory and clinical feasibility.

Chitosan Nanoparticles as an Alternative Therapeutic Approach for Knee Osteoarthritis Treatment: A Systematic Review

Osteoarthritis (OA) is a prevalent degenerative joint disease characterized by the progressive breakdown of cartilage, leading to pain, inflammation, and reduced joint function. There are many variations of conventional therapies that exist, however, none proven to halt or reverse cartilage degradation. Chitosan, a biocompatible and biodegradable polysaccharide, has emerged as a promising candidate in OA treatment due to its chondroprotective properties, and ability to enhance chondrocyte proliferation and suppress inflammatory mediators. Recent advancements in nanotechnology have led to the development of chitosan nanoparticles (NPs), which offer a novel and effective approach for addressing the limitations associated with standard chitosan formulations, such as poor solubility and limited tissue penetration. Chitosan NPs have demonstrated superior bioavailability, sustained drug release, and targeted delivery, leading to improved therapeutic outcomes in preclinical models. This review explores evidence-based the therapeutic potential of chitosan NPs in the management of knee osteoarthritis, focusing on their role in cartilage regeneration and drug delivery.

Hypothalamus Regulates Anabolic Metabolism of Articular Cartilage Superficial Chondrocytes through PGE2 Skeletal Interoception

Degeneration of articular cartilage is the key underlying cause of most joint-related diseases and yet little is known about its regeneration. Here, we report that skeletal interoception induces anabolic synthesis of superficial membrane by tuning down sympathetic norepinephrine (NE). Specifically, the superficial membrane is consumed during animal activity and anabolically renewed by the underneath chondrocytes in the superficial zone (SFZ). Notably, by stereotactic knockdown of sympathetic NE synthesis in the paraventricular nucleus, articular cartilage thickness increases. Moreover, deletion of the gene encoding the prostaglandin E2 (PGE2) receptor, EP4, in sensory nerves for ascending interoceptive pathway induces damage of superficial membrane and articular cartilage degeneration. In contrast, increase of interoceptive signaling by elevation of local PGE2 reduces sympathetic outflow to promote the anabolic renewal of superficial membrane. Importantly, inducible knockout of the β-2-adrenergic-receptor (Adrb2) in the SFZ chondrocytes damages superficial membrane and treadmill running aggravates the damage. Mechanistically, NE-mediated activation of Adrb2 induces internalization of Adrb2 and TGF-β type II receptor as a complex, thereby regulating TGF-β activity for articular cartilage homeostasis regeneration. Together, physical activity induces an anabolic renewal of the superficial membrane by downregulation hypothalamic NE for optimized thickness and integrity of articular cartilage.

Butyrate (short-chain fatty acid) alleviates lipopolysaccharide-binding proteins and improves physical function in knee osteoarthritis patients

Knee-osteoarthritis (OA) is often associated with increased intestinal permeability, potentially causing sarcopenia, and mobility issues. Current treatments are ineffective. The objective of this study was to investigate if butyrate improves sarcopenia and physical function in knee-OA patients, and if improvements correlate with changes in gut health, specifically intestinal permeability, and bacterial load. In this double-blind study, 60 OA patients received placebo, 52 received 300 mg butyrate daily for 12-weeks. Gut health (zonulin), and systemic bacterial load (lipopolysaccharide-binding proteins (LBP)) were assessed. Handgrip strength (HGS), Oxford knee scores (OKS), and short physical performance battery (SPPB) were measured at the beginning and end of the study to assess physical functionality. Patients taking butyrate showed improvement in HGS, walking speed, OKS scores, and maintained a better balance, walking ability and no decline in rising from chair, according to SPPB-scores. Butyrate lowered blood levels of zonulin, LBP, and CRP as markers of intestinal permeability, bacterial load, and inflammation, respectively (all p < 0.05). Regression analysis exhibited marked correlations of zonulin with HGS, OKS, walking speed, and SPPB scores in the butyrate-treated group. These observations suggest that butyrate could serve as a therapeutic option for sarcopenia and physical decline in OA, potentially by improving intestinal barrier function.

Efficacy, safety and tolerability of GSK3858279, an anti-CCL17 monoclonal antibody and analgesic, in healthy volunteers and patients with knee osteoarthritis pain: a phase I, randomised, double-blind, placebo-controlled, proof-of-mechanism and proof-of-concept study

OBJECTIVES

The objective of this study was to evaluate efficacy, safety and tolerability of the first-in-class, anti-CCL17 monoclonal antibody, GSK3858279, in treating knee osteoarthritis (OA) pain.

METHODS

This was a phase I, randomised, placebo-controlled, two-part, proof-of-mechanism and proof-of-concept study. In part A, healthy participants were randomised 3:1 to receive GSK3858279 as either single intravenous (0.1-10 mg/kg) doses, a subcutaneous (3 mg/kg up to 240 mg maximum) dose, or placebo, to evaluate safety and tolerability. In part B, participants with knee OA pain were randomised 1:1 to receive weekly subcutaneous 240 mg GSK3858279, or placebo, for 8 weeks, to assess safety and change from baseline (CFB) in average and worst knee pain intensity. Exploratory endpoints included CFB in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, function and stiffness scores.

RESULTS

GSK3858279 demonstrated greater median CFB (95% credible interval (CrI)) in average and worst knee pain intensity versus placebo (average, -1.18 (-2.15, -0.20); worst, -1.09 (-2.29, 0.12)) at week 8. Median CFB (95% CrI) for GSK3858279 versus placebo in WOMAC pain and function scores were -1.41 (-2.35, -0.46) and -1.29 (-2.28, -0.29), respectively, at week 8. Overall, 72% (26/36; part A) and 88% (21/24; part B) of participants receiving GSK3858279 experienced adverse events (AEs); with nasopharyngitis being the most common in part A and injection site reactions in part B. No serious AEs or deaths were observed.

CONCLUSION

GSK3858279 improved pain intensity and WOMAC pain and function scores in adults with knee OA pain and demonstrated favourable safety and tolerability in both healthy participants and adults with knee OA pain.

Co-delivery of IL-1Ra and SOX9 via AAV inhibits inflammation and promotes cartilage repair in surgically induced osteoarthritis animal models

Osteoarthritis (OA), a prevalent joint disorder, can lead to disability, with no effective treatment available. Interleukin-1 (IL-1) plays a crucial role in the progression of OA, and its receptor antagonist (IL-1Ra), a natural IL-1 inhibitor, represents a promising therapeutic target by obstructing the IL-1 signaling pathway. This study delivered IL-1Ra via adeno-associated virus (AAV), a gene therapy vector enabling long-term protein expression, to treat knee osteoarthritis (KOA) in animal models. scAAV-oIL-1Ra-I1/2 injected directly into the joint in both MMT/ACLT-induced KOA model rat improved abnormal gait (increasing footprint area and pressure), subchondral bone lesions, and significantly reduced cartilage wear and pathological scores. In the MMT-induced KOA rabbit model, weight-bearing asymmetry (indicating pain) improved after 8 weeks of scAAV-oIL-1Ra-I1/2 administration, and X-ray showed decreased K-L scores (severity grade), reduced cartilage loss, and lower pathology scores compared to untreated animals. Additionally, sex-determining region Y-type high mobility group box 9 (SOX9) was co-delivered with IL-1Ra via AAV in ACLT + MMT-induced KOA rats. The combined treatment significantly alleviated subchondral bone lesions, cartilage destruction, synovial inflammation, and pathological scores, demonstrating superior efficacy compared to either treatment administered alone. Co-delivering IL-1Ra and SOX9 inhibited IL-1 mediated inflammatory signaling, maintained cartilage homeostasis, and promoted its repair in KOA models, suggesting potential for clinical use.

Microfluidic chip-based co-culture system for modeling human joint inflammation in osteoarthritis research

Here we present a microfluidic model that allows for co-culture of human osteoblasts, chondrocytes, fibroblasts, and macrophages of both quiescent (M0) and pro-inflammatory (M1) phenotypes, maintaining initial viability of each cell type at 24 h of co-culture. We established healthy (M0-based) and diseased (M1-based) joint models within this system. An established disease model based on supplementation of IFN-γ and lipopolysaccharide in cell culture media was used to induce an M1 phenotype in macrophages to recapitulate inflammatory conditions found in Osteoarthritis. Cell viability was assessed using NucBlue™ Live and NucGreen™ Dead fluorescent stains, with mean viability of 83.9% ± 14% and 83.3% ± 12% for healthy and diseased models, respectively, compared with 93.3% ± 4% for cell in standard monoculture conditions. Cytotoxicity was assessed via a lactate dehydrogenase (LDH) assay and showed no measurable increase in lactate dehydrogenase release into the culture medium under co-culture conditions, indicating that neither model promotes a loss of cell membrane integrity due to cytotoxic effects. Cellular metabolic activity was assessed using a PrestoBlue™ assay and indicated increased cellular metabolic activity in co-culture, with levels 5.9 ± 3.2 times mean monolayer cell metabolic activity levels in the healthy joint model and 5.3 ± 3.4 times mean monolayer levels in the diseased model. Overall, these findings indicate that the multi-tissue nature of in vivo human joint conditions can be recapitulated by our microfluidic co-culture system at 24 h and thus this model serves as a promising tool for studying the pathophysiology of rheumatic diseases and testing potential therapeutics.

Comparative Analysis of the Therapeutic Potential of Extracellular Vesicles Secreted by Aged and Young Bone Marrow-Derived Mesenchymal Stem Cells in Osteoarthritis Pathogenesis

Osteoarthritis (OA), a joint disease, burdens global healthcare due to aging and obesity. Recent studies show that extracellular vesicles (EVs) from bone marrow-derived mesenchymal stem cells (BMSCs) contribute to joint homeostasis and OA management. However, the impact of donor age on BMSC-derived EV efficacy remains underexplored. In this study, we investigated EV efficacy from young BMSCs (2-month-old) in mitigating OA, contrasting them with EVs from aged BMSCs (27-month-old). The study used destabilisation of the medial meniscus (DMM) surgery on mouse knee joints to induce accelerated OA. Cartilage degeneration markers and senescence markers' expression levels were investigated in response to EV treatment. The therapeutic impact of EVs on chondrocytes under inflammatory responses was also evaluated. Despite having similar morphologies, EVs from young BMSCs markedly decreased senescence and improved chondroprotection by activating the PTEN pathway while simultaneously suppressing the upregulation of the PI3K/AKT pathways, proving to be more effective than those from older BMSCs in vitro. Furthermore, intraperitoneal injections of EVs from young donors significantly mitigated OA progression by preserving cartilage and reducing synovitis in a surgical OA model using DMM in mice. These findings highlight that donor age as a critical determinant in the therapeutic potential of BMSC-derived EVs for clinical use in OA treatment.

Intermittent hypoxic stimulation promotes efficient expression of Hypoxia-inducible factor-1α and exerts a chondroprotective effect in an animal osteoarthritis model

Hypoxia-inducible factor-1α plays an important role in the homeostasis of articular cartilage in hypoxic environments. Therefore, modulation of hypoxia-inducible factor-1α by regulating the oxygen environment could be a useful treatment for osteoarthritis. This study aimed to assess the chondroprotective effects of intermittent hypoxia on cultured chondrocytes and an animal model of osteoarthritis. In vitro, human chondrocytes were exposed to 2 h of hypoxic stimulation three times at 1-h intervals, and protein and gene expression of hypoxia-inducible factor-1α, ACAN, and cell viability was measured over time. In vivo, 8-week-old male Wistar rats were injected with monosodium iodoacetate to induce osteoarthritis and then reared in 12% hypoxia for 24 h, followed by 24 h in steady oxygen, repeated alternately for a total of 28 days. A histological analysis was performed on days 8 and 28. In the intermittent hypoxia group, each protein expression increased with each repeated hypoxic stimulation to human chondrocytes; finally, the protein level was significantly higher with intermittent hypoxia than with continuous hypoxic stimulation, cell viability was increased, and gene expression was not significantly increased. In the osteoarthritis animal model, for 8 days, there were stronger hypoxia-inducible factor-1α staining and no significant differences in articular cartilage destruction. Furthermore, for 28 days, there was significantly less articular cartilage destruction in the rat osteoarthritis model with intermittent hypoxia than with steady oxygen rearing. Intermittent hypoxia increased cartilage metabolism by increasing hypoxia-inducible factor-1α proteins in articular chondrocytes, which may be effective in preventing articular cartilage degeneration in a rat osteoarthritis model.

Body mass index and health-related quality of life of outpatients with knee osteoarthritis: evidence from a cross-sectional study

PURPOSE

To estimate the health-related quality of life (HRQoL) of knee osteoarthritis outpatients in China overall and by body mass index (BMI), and to explore the factors associated with knee osteoarthritis.

METHOD

This was a cross-sectional study in which outpatients with knee osteoarthritis were recruited from three tertiary hospitals in China from June 2020 to May 2021. The EuroQoL five-dimensional instrument was used to measure HRQoL. Descriptive analysis, one-way analysis of variance, and a Tobit regression model were performed.

RESULTS

One thousand and eight questionnaires were distributed, and nine hundred and fifty-two participants were included. The mean age was 61.71 years, and 61.03% of the participants were female. The mean health utility was 0.751 (95% CI 0.737, 0.765). The health utility varied significantly according to BMI: underweight = 0.627 (95% CI 0.536, 0.719), normal = 0.764 (95% CI 0.744, 0.784), overweight = 0.755 (95% CI 0.733, 0.776), and obese = 0.728 (95%CI 0.681, 0.776). Additionally, outpatients with knee osteoarthritis who were younger, had received treatment in the past six months, and had a disease duration shorter than 2 years had significantly higher HRQoL scores.

CONCLUSION

The HRQoL of knee osteoarthritis outpatients was considerably impaired and was significantly associated with BMI. These findings emphasize the importance of weight examination and management in outpatients with knee osteoarthritis for healthcare providers. Supplementary data were provided for public health-related policies and health economics studies, contributing to the development of effective management strategies and increasing the breadth of knowledge of HRQoL in outpatients with knee osteoarthritis.

Clinical research progress of umbilical cord blood mesenchymal stem cells in Knee articular cartilage repair: A review

Umbilical cord blood mesenchymal stem cells (UCB-MSCs) are a type of adult stem cell with multipotent differentiation potential and immunoregulatory functions, primarily found in neonatal cord blood. Due to their noninvasive collection method, abundance, and ease of preservation, UCB-MSCs represent a promising biological material. This review examines the clinical research on UCB-MSCs in knee articular cartilage repair, highlighting their regenerative potential for treating knee joint cartilage defects. Our aim is to provide insights into current applications and propose directions for future research, focusing on optimizing clinical use and enhancing patient outcomes.

CN7:1h Alleviates Inflammation, Apoptosis and Extracellular Matrix Degradation in Osteoarthritis by Modulating the NF-κB and mTOR Pathways

Osteoarthritis (OA) is a degenerative joint disease with a complex aetiology, which includes inflammation, cellular growth dysregulation and extracellular matrix (ECM) degradation. This study investigated the therapeutic potential of a small-molecule compound, 2-amino-4-(3,4,5-trimethoxyphenyl)-4H-benzo[h]chromene-3-carbonitrile (CN7:1h) in modulating these critical biochemical pathways in OA. Cellular models and rat models of OA were used to explore the impact of CN7:1h on the nuclear factor kappa light chain enhancer of activated B cells (NF-κB) and mechanistic target of rapamycin (mTOR) signalling pathways. Parameters such as autophagy, apoptosis and ECM preservation were evaluated. CN7:1h demonstrated a non-cytotoxic profile at a concentration as high as 140 μM as confirmed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. At a concentration of 5 μM, CN7:1h was shown to inhibit the activation of NF-κB and mTOR pathways. CN7:1h was also shown to promote autophagy and reduce apoptosis in cellular models. In rat models, CN7:1h facilitated cartilage repair and demonstrating the therapeutic efficacy of this compound. In conclusion, CN7:1h is a promising bioactive compound for the modulation of key biochemical pathways with therapeutic benefits in degenerative conditions, such as OA. Its high bioavailability and lack of cytotoxicity make CN7:1h an excellent candidate for further research aimed at clinical applications.

Advances in the pathology and treatment of osteoarthritis

BACKGROUND

Osteoarthritis (OA), a widespread degenerative joint disease, predominantly affects individuals from middle age onwards, exhibiting non-inflammatory characteristics. OA leads to the gradual deterioration of articular cartilage and subchondral bone, causing pain and reduced mobility. The risk of OA increases with age, making it a critical health concern for seniors. Despite significant research efforts and various therapeutic approaches, the precise causes of OA remain unclear.

AIM OF REVIEW

This paper provides a thorough examination of OA characteristics, pathogenic mechanisms at various levels, and personalized treatment strategies for different OA stages. The review aims to enhance understanding of disease mechanisms and establish a theoretical framework for developing more effective therapeutic interventions.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review systematically examines OA through multiple perspectives, integrating current knowledge of clinical presentation, pathological mechanisms, and associated signaling pathways. It assesses diagnostic methods and reviews both pharmacological and surgical treatments for OA, as well as emerging tissue engineering approaches to manage the disease. While therapeutic strategies such as exercise, anti-inflammatory drugs, and surgical interventions are employed to manage symptoms and modify joint structure, none have been able to effectively halt OA's advancement or achieve long-lasting symptom relief. Tissue engineering strategies, such as cell-seeded scaffolds, supportive matrices, and growth factor delivery, have emerged as promising approaches for cartilage repair and OA treatment. To combat the debilitating effects of OA, it is crucial to investigate the molecular basis of its pathogenesis and seek out innovative therapeutic targets for more potent preventive and treatment strategies.

Current status of nanofat in the management of knee osteoarthritis: A systematic review

BACKGROUND

Osteoarthritis (OA) is a prevalent joint disorder requiring innovative treatment approaches.

AIM

To evaluate the use of nanofat, a specialized form of adipose tissue-derived cells, in the treatment of OA, by examining its efficacy, safety profile, mechanisms of action, comparative effectiveness, and long-term outcomes.

METHODS

A comprehensive review of preclinical studies, clinical trials, and in vitro investigations was conducted. The included studies provided insights into the potential role of nanofat in OA treatment, addressing its efficacy, safety profile, mechanisms of action, comparative effectiveness, and long-term outcomes.

RESULTS

Clinical studies consistently reported the efficacy of nanofat in providing pain relief and functional improvement in patients with OA. Local adverse events were limited to the injection site, such as localized pain and inflammation, and resolved within a few days to weeks. Systemic adverse events were rare, and no significant long-term complications were observed. Mechanistically, nanofat was found to enhance chondrocyte proliferation, reduce inflammation, and promote angiogenesis, thereby contributing to its therapeutic effects.

CONCLUSION

Nanofat therapy holds promise as a therapeutic option for managing OA, providing pain relief, functional improvement, and potential tissue regeneration. The safety profile of nanofat treatment appears favorable, but long-term data are still limited. Standardized protocols, larger randomized controlled trials, longer follow-up periods, and cost-effectiveness evaluations are warranted to establish optimal protocols, comparative effectiveness, and long-term outcomes. Despite current limitations, nanofat therapy demonstrates translational potential and should be considered in clinical practice for OA treatment, with careful patient selection and monitoring.

Investigating the Potential of Magnesium Microparticles on Cartilage and Bone Regeneration Utilizing an In Vitro Osteoarthritis Model

Osteoarthritis (OA) is a significant condition that profoundly impacts synovial joints, including cartilage and subchondral bone plate. Biomaterials that can impede OA progression are a promising alternative or supplement to anti-inflammatory and surgical interventions. Magnesium (Mg) alloys known for bone regeneration potential were assessed in the form of Mg microparticles regarding their impact on tissue regeneration and prevention of OA progression. In vitro assays based on mesenchymal stem cells (SCP-1) were applied to evaluate the Mg microparticle's compatibility and function. Biocompatibility documented through live-dead staining and lactate dehydrogenase assay revealed a 90% cell viability at a concentration below 10 mM after 3 days of exposure. An in vitro OA model based on the supplementation of the cytokines IL-1β, and TNF-α was established and disclosed the effect of Mg degradation products in differentiating SCP-1 cells. Sustained differentiation was confirmed through extracellular matrix staining and increased gene marker expression. The Mg supplementation reduced the release of inflammatory cytokines (IL-6 and IL-8) while promoting the expression of proteins such as collagen X, collagen I, and osteopontin in a time-dependent manner. The in vitro study suggests that Mg microparticles hold a therapeutic potential for OA treatment with their ability to support bone and cartilage repair mechanisms even under inflammatory conditions.

Role of Plant Materials with Anti-inflammatory Effects in Phytotherapy of Osteoarthritis

Osteoarthritis (OA) is a common chronic articular degenerative disease characterized by articular cartilage degradation, synovial inflammation/immunity, and subchondral bone lesions. Recently, increasing interest has been devoted to treating or preventing OA with herbal medicines. The mechanism of action of plant raw materials used in osteoarthrosis treatment is well documented. They are sought after because of the high frequency of inflammation of the knee joint among both elderly and young people engaged in sports in which their knee joints are often exposed to high-stress conditions. The purpose of this work was to present some most effective and safe plant medicines with proven mechanisms of action that can help to alleviate the growing social problem of osteoarthrosis caused in recent years. A review of the available literature based primarily on the latest editions of ESCOP and EMA monographs and the latest scientific papers has made it possible to select and propose medical management of osteoarthrosis by ranking plant medicines according to their effectiveness. Clinical studies of raw plant materials, such as Harpagophyti radix, Olibanum indicum, and Urticae foliumet herba have indicated that these drugs should be considered the first choice in osteoarthrosis treatment. The efficacy of Rosae pseudo-fructus, Salicis cortex, Filipendulae ulmariae flos et herba, Ribis nigri folium, and externally applied Capsici fructus and Symphyti radix, has also been proven by pharmacological studies. All the plant medicines mentioned in the paper have been studied in detail in terms of their phytochemistry, which can help doctors in their decisionmaking in the treatment of osteoarthrosis.

Modulation of IFN-γ induced macrophage inflammatory responses via indomethacin-loaded NLCs for OA management

Macrophages are the main cells present in the synovial membrane. They play an important role in the development and progression of osteoarthritis (OA). After the establishment of the disease macrophages mostly adopt a pro-inflammatory secretory phenotype (OA phenotype) further inducing cartilage degradation. Indomethacin (IND) is a non-steroidal anti-inflammatory drug (NSAID) able to inhibit the synthesis of prostaglandins mediated by both cyclooxygenase isoforms depicting a potent anti-inflammatory capacity. However, the lack of specificity and short half-like of free drugs within the joint cavity limits its utility in controlling inflammation after intra-articular administration. This study aims at developing IND loaded glycosylated nanostructured lipid carriers (NLCs) to selectively target macrophages and promote their reprogramming to an anti-inflammatory phenotype. This approach focused on the local administration of the NLCs, offers a promising therapeutic strategy for treating OA by modulating the inflammatory environment within the joint. NLCs will be designed by combining experimental and in silico docking analyses, and thoroughly characterized to obtain drug delivery systems with high stability and suitable physicochemical properties. The proposed mannose-functionalized systems exhibited adequate particle sizes (≈ 70 nm) and positive surface charges (> 20 mV) to be efficiently retained in the joint cavity. Moreover, the developed NLCs demonstrated effective and specific uptake by OA-like macrophages leading to a significant decrease in the secretion of the pro-inflammatory cytokines IL-6, IL-8 and TNF-α similarly to the free drug. Therefore, these systems effectively reprogrammed OA-associated macrophages to adopt a more regenerative phenotype, offering a promising strategy for managing inflammation in OA.

Understanding the impact of diabetes on bone health: A clinical review

Diabetic bone disease, a form of secondary osteoporosis, is characterized by weakened bones and an increased risk of fractures, especially in patients with type 2 diabetes (T2D). This review explores the key mechanisms driving this condition, including hyperglycemia, insulin resistance, advanced glycation end products (AGEs), and proinflammatory cytokines, all of which disturb normal bone turnover by disrupting the functions of osteoblasts and osteoclasts. We examine the roles of bone turnover and mineralization, as well as how microvascular complications affect bone microarchitecture. Additionally, the influence of gut hormones, such as GLP-1 and GIP, and gut microbiota, particularly species like Akkermansia muciniphila, on the gut-bone axis is discussed, as these factors play a role in regulating bone density and structure. While T2D patients may show normal or even elevated bone mineral density (BMD), the underlying quality of bone is often compromised, leading to increased fragility. This review integrates current knowledge on the molecular, hormonal, and microbial interactions contributing to diabetic bone disease. By highlighting these pathways, we aim to offer insights into potential therapeutic strategies and inform future research aimed at improving the diagnosis, treatment, and overall management of this condition.

Progressive use of nanocomposite hydrogels materials for regeneration of damaged cartilage and their tribological mechanical properties

Osteoarthritis (OA) is a non-inflammatory deteriorating debilitating state that bring about remarkable health and economic issues globally. Break down/deterioration of the articular cartilage (AC) is one of the pathologic characteristics of osteoarthritis (OA). Nanocomposite hydrogels (NCH) materials are evolving as a potential class of scaffolds for organ regeneration and tissue engineering. In recent years, innovative hydrogels specifically loaded with nanoparticles have been developed and synthesized with the goal of changing conventional cartilage treatments. The detailed development of a tailored nanocomposite hydrogels (NCH) material utilized for tissue engineering is presented in this review study. Also, the mechanical characteristics, particularly the tribological behavior, of these produced NCH have been highlighted. Large amounts of research and data on the hydrogel substance utilized in cartilage healing are summarized in the current review study. When determining future research gaps in the area of hydrogels for cartilage regeneration, such information will provide researchers an advantage to further develop NCH.

The Intra-Articular Delivery of a Low-Dose Adeno-Associated Virus-IL-1 Receptor Antagonist Vector Alleviates the Progress of Arthritis in an Osteoarthritis Rat Model

Background/Objectives: Interleukin-1 (IL-1) is a pivotal mediator in the pathological progression of osteoarthritis (OA), playing a central role in disease progression. However, the rapid clearance of IL-1 receptor antagonist (IL-1Ra) from the joints may hinder the efficacy of intra-articular IL-1Ra injections in reducing OA-associated pain or cartilage degradation. Methods: Sustaining sufficient levels of IL-1Ra within the joints via adeno-associated virus (AAV)-mediated gene therapy presents a promising therapeutic strategy for OA. In this study, we constructed an IL-1Ra expression cassette employing intron insertion in the coding sequence (CDS) region to enhance protein expression levels. Furthermore, we incorporated precisely targeted liver-specific microRNA (miRNA) sequences to specifically downregulate transgene expression within hepatic tissues, thereby ensuring more targeted and controlled regulation of gene expression. Results: A rat model of OA was employed to compare the efficacy of AAV5 and AAV9 for IL-1Ra delivery at both high and low doses. It was observed that low-dose, but not high-dose, AAV9-IL-1Ra resulted in a significant reduction in joint swelling, accompanied by a decrease in the diameter of the affected area and the preservation of biomarkers associated with trabecular bone integrity. Conclusions: These results highlight the great potential of AAV9-IL-1Ra in osteoarthritis therapy, with the promise of achieving long-term improvement through a single intra-articular injection.

Efficacy of Autologous Micrografting Technology in Managing Osteoarthritis Pain: A Pilot Study

Osteoarthritis (OA) is one of the most common joint diseases worldwide, predominantly present in elderly people. Being a major source of pain for patients, it is debilitating and leads inevitably to a reduction in quality of life. The management of OA needs a personalized and multidimensional approach, resulting in the emergence of new regenerative and non-invasive methods, such as the use of micrografts. In this pilot study, Rigenera® Technology was employed to obtain micrografts of cartilage tissue to be injected into the knees of 10 patients with osteoarthritic pain. To assess the efficacy of the treatment concerning pain reduction at this site, patients were asked to complete KOOS and WOMAC questionnaire and a VAS test before and after the procedure. The results presented in this article show how Rigenera® treatment can potentially improve OA symptoms, alleviating pain in patients.

Intraarticular gold microparticles using hyaluronic acid as the carrier for hip osteoarthritis. A 2-year follow-up pilot study

We recently conducted a pilot study in which we discovered that introducing metallic gold microparticles into the knee joint can help reduce pain caused by osteoarthritis for up to two years. Additionally, we identified significant proteomic changes in the synovial fluid and serum within eight weeks of the procedure. In this study, we aimed to evaluate whether there may be a clinical relevant effect of intra-articular injection of gold microparticles on hip osteoarthritis. A cohort of 22 patients, aged ≥ 18 years, with pain ≥ 3 months, and Kellgren-Lawrence OA grade 2-4, were included. Metallic gold 20 mg, 72.000 pieces, 20-40 µ-meter BerlockMicroImplants (BMI) were injected into the hip joint using hyaluronic acid as the carrier. In total, we treated 26 hip joints. The primary outcome was the Western Ontario and McMaster Universities Arthritis Index (WOMAC). WOMAC pain decreased from 11 (2-20 to 3 (0-8), stiffness from 6 (0-8) to 1 (0-4), and activity from 43 (18-68) to 11 (0-27), all P = 0.0001. When adjusting for the minimally relevant differences, the P-values were 0.0015 for WOMAC pain, 0.26 for stiffness, and 0.011 for activity. Combined intraarticular treatment with metallic gold microparticles and hyaluronic acid may improve hip joint pain and function. Joint stiffness did not improve when assessed against the minimal clinically relevant difference. This study suggests a basis for a future placebo-controlled randomized trial of gold microparticles and hyaluronic acid in hip osteoarthritic patients.

Iron overload is positively associated with the incidence of osteoarthritis: A NHANES cross-sectional study

With the aging of the global population and the increase in the number of people with conditions such as obesity, the incidence of osteoarthritis (OA) is increasing annually. Clinical studies have shown that excessive accumulation of iron in joints is associated with age-related OA. However, there have been no reports on the relationship between iron metabolism and osteoarthritis. A STROBE-compliant cross-sectional observational study, was carried out and analyzed from the National Health and Nutrition Examination Survey from 2001 to 2020, including data on serum iron, transferrin saturation, serum ferritin, total iron-binding capacity, and transferrin receptors, as well as data on osteoarthritis. This cross-sectional study was conducted to explore the relationship between serum iron levels, osteoarthritis, and related metabolic factors. By adjusting the model and using quantile logistic regression models, the interaction between human body iron content and the aforementioned variables was analyzed. A total of 56,323 participants over 5 cycles were assessed for iron levels. After adjusting the model for age, sex, race, education level, marital status, total energy intake, physical activity, drinking, BMI, smoking, hypertension, and diabetes, we found that in different quantile regression results, serum iron was associated with OA, Q4: OR = 1.231 (95%CI: 1.009-1.501, P < .05). Ferritin is associated with OA, Q2: OR = 1.309 (95%CI: 1.012-1.692, P < .05); Q3: OR = 1.424 (95%CI: 1.129-1.797, P < .01); Q4: OR = 1.280 (95%CI: 1.013-1.616, P < .05). This cross-sectional study found that serum iron and transferrin saturation levels were positively correlated with OA incidence, suggesting that iron overload is a risk factor for OA. Large-sample prospective cohort studies are needed to confirm the correlation between iron overload and OA.

Differential effects of alendronate on chondrocytes, cartilage matrix and subchondral bone structure in surgically induced osteoarthritis in mice

Bisphosphonates (BP) are considered a treatment option for osteoarthritis (OA) due to reduction of OA-induced microtrauma in the bone marrow, stabilization of subchondral bone (SB) layer and pain reduction. The effects of high-dose alendronate (ALN) treatment on SB and articular cartilage after destabilization of the medial meniscus (DMM) or Sham surgery of male C57Bl/6J mice were analyzed. We performed serum analysis; histology and immunohistochemistry to assess the severity of OA and a possible pain symptomatology. Subsequently, the ratio of bone volume to total volume (BV/TV), epiphyseal trabecular morphology and the bone mineral density (BMD) was analyzed by nanoCT. Serum analysis revealed a reduction of ADAMTS5 level. The histological evaluation displayed no protective effect of ALN-treatment on cartilage erosion. NanoCT-analysis of the medial epiphysis revealed an increase of BV/TV in ALN-treated mice. Only the DMM group had significantly higher SB volume accompanied by decreased subchondral bone surface. Furthermore Nano-CT analysis revealed an increase in trabecular density and number, a decreased BMD and reduced osteophyte formation in the ALN mice. ALN treatment affected bone micro-architecture by reducing osteophytosis with simultaneous increasing subchondral bone plate thickness, trabecular thickness and BMD. Accordingly, ALN cannot be considered as a potential treatment strategy in general, however in a subgroup of patients with high bone turnover in an early-stage of OA, ALN might be an option when applied during a restricted time frame.

Systems analysis of miR-199a/b-5p and multiple miR-199a/b-5p targets during chondrogenesis

Changes in chondrocyte gene expression can contribute to the development of osteoarthritis (OA), and so recognition of the regulative processes during chondrogenesis can lead to a better understanding of OA. microRNAs (miRNAs) are key regulators of gene expression in chondrocytes/OA, and we have used a combined experimental, bioinformatic, and systems biology approach to explore the multiple miRNA-mRNA interactions that regulate chondrogenesis. A longitudinal chondrogenesis bioinformatic analysis identified paralogues miR-199a-5p and miR-199b-5p as pro-chondrogenic regulators. Experimental work in human cells demonstrated alteration of miR-199a-5p or miR-199b-5p expression led to significant inverse modulation of key chondrogenic genes and extracellular matrix production. miR-199a/b-5p targets FZD6, ITGA3 and CAV1 were identified by inhibition experiments and verified as direct targets by luciferase assay. The experimental work was used to generate and parameterise a multi-miRNA 14-day chondrogenesis kinetic model to be used as a repository for the experimental work and as a resource for further investigation of this system. This is the first multi-miRNA model of a chondrogenesis-based system, and highlights the complex relationships between regulatory miRNAs, and their target mRNAs.

Mesenchymal stem cells for chronic knee pain secondary to osteoarthritis: A systematic review and meta-analysis of randomized trials

OBJECTIVE

To assess the effectiveness of mesenchymal stem cells (MSCs) for chronic knee pain secondary to osteoarthritis (OA).

METHODS

We searched MEDLINE, EMBASE, CINAHL, and Cochrane Central to September 2023 for trials that (1) enrolled patients with chronic pain associated with knee OA, and (2) randomized them to MSC therapy vs. placebo or usual care. We performed random-effects meta-analysis and used Grading of Recommendations, Assessment, Development, and Evaluation to assess the certainty of evidence.

RESULTS

We included 16 trials (807 participants). At 3-6 months, MSC therapy probably results in little to no difference in pain relief (weighted mean difference [WMD] -0.74 cm on a 10 cm visual analog scale [VAS], 95% confidence interval [95%CI] -1.16 to -0.33; minimally important difference [MID] 1.5 cm) or physical functioning (WMD 2.23 points on 100-point 36-item Short Form Survey (SF-36) physical functioning subscale, 95%CI -0.97 to 5.43; MID 10-points; both moderate certainty). At 12 months, injection of MSCs probably results in little to no difference in pain (WMD -0.73 cm on a 10 cm VAS, 95%CI -1.69 to 0.24; moderate certainty) and may improve physical functioning (WMD 19.36 points on 100-point SF-36 PF subscale, 95%CI -0.19 to 38.9; low certainty). MSC therapy may increase risk of any adverse events (risk ratio [RR] 2.67, 95%CI 1.19 to 5.99; low certainty) and pain and swelling of the knee joint (RR 1.58, 95%CI 1.04 to 2.38; low certainty).

CONCLUSIONS

Intra-articular injection of MSCs for chronic knee pain associated with OA probably provides little to no improvement in pain or physical function.

Reduced Cell Migration in Human Chondrocyte Sheets Increases Tissue Stiffness and Cartilage Protein Production

BACKGROUND

Chondrogenic differentiation medium (CDM) is usually used to maintain chondrogenic activity during chondrocyte sheet production. However, tissue qualities remain to be determined as to what factors improve cell functions. Moreover, the relationship between CDM and cell migration proteins has not been reported.

METHOD

In this study, the effect of CDM on the behavior of chondrocyte sheets was investigated. Structural analysis, mechanical testing and proteomics were performed to observe tissue qualities. The relationship between CDM and cell migration proteins were investigated using time-lapse observations and bioinformatic analysis.

RESULTS

During 48 h, CDM affected the chondrocyte behaviors by reducing cell migration. Compared to the basal medium, CDM impacted the contraction of monolayered chondrocyte sheets. At day 7, the contracted sheets increased tissue thickness and improved tissue stiffness. Cartilage specific proteins were also upregulated. Remarkedly, the chondrocyte sheets in CDM displayed downregulated proteins related to cell migration. Bioinformatic analysis revealed that TGFβ1 was shown to be associated with cartilage functions and cell migration. Pathway analysis of chondrocyte sheets in CDM also revealed the presence of a TGFβ pathway without activating actin production, which might be involved in synthesizing cartilage-specific proteins. Cell migration pathway showed MAPK signaling in both cultures of the chondrocyte sheets.

CONCLUSION

Reduced cell migration in the chondrocyte sheet affected the tissue quality. Using CDM, TGFβ1 might trigger cartilage protein production through the TGFβ pathway and be involved in cell migration via the MAPK signaling pathway. Understanding cell behaviors and their protein expression would be beneficial for developing high-quality tissue-engineered cartilage.

Unlocking the full potential of mesenchymal stromal cell therapy for osteoarthritis through machine learning-based in silico trials

Despite the potential of mesenchymal stromal cells (MSCs) in osteoarthritis (OA) treatment, the challenge lies in addressing their therapeutic inconsistency. Clinical trials revealed significantly varied therapeutic outcomes among patients receiving the same allogenic MSCs but different treatment regimens. Therefore, optimizing personalized treatment strategies is crucial to fully unlock MSCs' potential and enhance therapeutic consistency. We employed the XGBoost algorithm to train a self-collected database comprising 37 published clinical reports to create a model capable of predicting the probability of effective pain relief and Western Ontario and McMaster Universities (WOMAC) index improvement in OA patients undergoing MSC therapy. Leveraging this model, extensive in silico simulations were conducted to identify optimal personalized treatment strategies and ideal patient profiles. Our in silico trials predicted that the individually optimized MSC treatment strategies would substantially increase patients' chances of recovery compared to the strategies used in reported clinical trials, thereby potentially benefiting 78.1%, 47.8%, 94.4% and 36.4% of the patients with ineffective short-term pain relief, short-term WOMAC index improvement, long-term pain relief and long-term WOMAC index improvement, respectively. We further recommended guidelines on MSC number, concentration, and the patients' appropriate physical (body mass index, age, etc.) and disease states (Kellgren-Lawrence grade, etc.) for OA treatment. Additionally, we revealed the superior efficacy of MSC in providing short-term pain relief compared to platelet-rich plasma therapy for most OA patients. This study represents the pioneering effort to enhance the efficacy and consistency of MSC therapy through machine learning applied to clinical data. The in silico trial approach holds immense potential for diverse clinical applications.

The Potential of Intra-Articular Therapies in Managing Knee Osteoarthritis: A Systematic Review

BACKGROUND

Knee osteoarthritis (KOA) is a common degenerative and progressive joint disorder that negatively influences patients' quality of life. Intra-articular therapies, such as hyaluronic acid (HA) and platelet-rich plasma (PRP), have garnered attention for their potential to manage osteoarthritis OA symptoms effectively. This systematic review aims to identify the effectiveness and safety of HA and PRP treatment modalities in treating KOA.

METHODS

A literature search was conducted across MEDLINE (PubMed), Web of Science Core Collection, and Science Direct Collection Elsevier. Twenty-three randomized controlled trials, cohort studies, and observational studies were included in the review. The selection criteria focused on studies published in English within the last 10 years, involving subjects with KOA treated with intra-articular injections of HA or PRP and reporting on pain, function, or overall treatment efficacy outcomes.

RESULTS

The analysis showed that both HA and PRP significantly improve functionality and reduce pain in KOA patients. High molecular weight HA consistently reduced pain and improved joint mobility in various studies. PRP had better long-term outcomes when combined with HA, leading to greater pain reduction and functional improvement. Both therapies had generally favorable safety profiles, with only minor adverse events reported. However, there were potential biases identified across the studies, such as selection, performance, detection, and reporting biases, which impacted the reliability of the results.

CONCLUSIONS

Intra-articular treatments with HA and PRP show promise in managing knee osteoarthritis, with personalized treatment plans and further research needed to confirm these findings.

Knee osteoarthritis: disease burden, available treatments, and emerging options

Osteoarthritis (OA) is a prevalent condition that affects nearly 528 million people worldwide, including 23% of the global population aged ⩾40, and is characterized by progressive damage to articular cartilage, which often leads to substantial pain, stiffness, and reduced mobility for affected patients. Pain related to OA is a barrier to maintaining physical activity and a leading cause of disability, accounting for 2.4% of all years lived with disability globally, reducing the ability to work in 66% of US patients with OA and increasing absenteeism in 21% of US patients with OA. The joint most commonly involved in OA is the knee, which is affected in about 60%-85% of all OA cases. The aging population and longer life expectancy, coupled with earlier and younger diagnoses, translate into a growing cohort of symptomatic patients in need of alternatives to surgery. Despite the large number of patients with knee OA (OAK) worldwide, the high degree of variability in patient presentation can lead to challenges in diagnosis and treatment. Multiple society guidelines recommend therapies for OAK, but departures from guidelines by healthcare professionals in clinical settings reflect a discordance between evidence-based treatment algorithms and routine clinical practice. Furthermore, disease-modifying pharmacotherapies are limited, and treatment for OAK often focuses solely on symptom relief, rather than underlying causes. In this narrative review, we summarize the patient journey, analyze current disease burden and nonsurgical therapy recommendations for OAK, and highlight emerging and promising therapies-such as cryoneurolysis, long-acting corticosteroids, and gene therapies-for this debilitating condition.

Mechanisms and Intervention of Prebiotic Foods in Musculoskeletal Health

The review focuses primarily on collating and analyzing the mechanistic research data that discusses the function of prebiotics to halt the frailty of musculoskeletal system. Musculoskeletal diseases (MSDs) are frequently reported to co-occur within their own categories of conditions, such as osteoarthritis, rheumatoid arthritis, gouty arthritis, and psoriatic arthritis owing to their overlapping pathogenesis. Consequently, the same drugs are often used to manage the complications of most types. A few recent studies have addressed the therapeutic functions of gut microbes toward those commonly shared MSD pathway targets. Improving microbial diversity and enriching their population in the gut would promote the regeneration and recovery of the musculoskeletal system. Prebiotics are usually nondigestible substrates that are selectively used or digested by the gut microbes conferring health promotion. The microbial fermentation of prebiotics generates numerous host-beneficial therapeutic molecules. This study inspects the presumptive functions of plant-derived prebiotics for the growth and restoration of intestinal microbiota and the consequent improvement of skeletal health. The review also highlights the discrete functions of prebiotics against inflammation, autoimmunity, infection, physiologic overloading mechanism, and aging-associated loss of metabolism in MSD.

Promoting Articular Cartilage Regeneration through Microenvironmental Regulation

In recent years, as the aging population continues to grow, osteoarthritis (OA) has emerged as a leading cause of disability, with its incidence rising annually. Current treatments of OA include exercise and medications in the early stages and total joint replacement in the late stages. These approaches only relieve pain and reduce inflammation; however, they have significant side effects and high costs. Therefore, there is an urgent need to identify effective treatment methods that can delay the pathological progression of this condition. The changes in the articular cartilage microenvironment, which are complex and diverse, can aggravate the pathological progression into a vicious cycle, inhibiting the repair and regeneration of articular cartilage. Understanding these intricate changes in the microenvironment is crucial for devising effective treatment modalities. By searching relevant research articles and clinical trials in PubMed according to the keywords of articular cartilage, microenvironment, OA, mechanical force, hypoxia, cytokine, and cell senescence. This study first summarizes the factors affecting articular cartilage regeneration, then proposes corresponding treatment strategies, and finally points out the future research direction. We find that regulating the opening of mechanosensitive ion channels, regulating the expression of HIF-1, delivering growth factors, and clearing senescent cells can promote the formation of articular cartilage regeneration microenvironment. This study provides a new idea for the treatment of OA in the future, which can promote the regeneration of articular cartilage through the regulation of the microenvironment so as to achieve the purpose of treating OA.

Coenzyme-A-Responsive Nanogel-Coated Electrochemical Sensor for Osteoarthritis-Detection-Based Genetic Models

An electrochemical sensor sensitive to coenzyme A (CoA) was designed using a CoA-responsive polyallylamine-manganese oxide-polymer dot nanogel coated on the electrode surface to detect various genetic models of osteoarthritis (OA). The CoA-responsive nanogel sensor responded to the abundance of CoA in OA, causing the breakage of MnO2 in the nanogel, thereby changing the electroconductivity and fluorescence of the sensor. The CoA-responsive nanogel sensor was capable of detecting CoA depending on the treatment time and distinguishing the response towards different OA genetic models that contained different levels of CoA (wild type/WT, NudT7 knockout/N7KO, and Acot12 knockout/A12KO). The WT, N7KO, and A12KO had distinct resistances, which further increased as the incubation time were changed from 12 h (R12h = 2.11, 2.40, and 2.68 MΩ, respectively) to 24 h (R24h = 2.27, 2.59, and 2.92 MΩ, respectively) compared to the sensor without treatment (Rcontrol = 1.63 MΩ). To simplify its application, the nanogel sensor was combined with a wireless monitoring device to allow the sensing data to be directly transmitted to a smartphone. Furthermore, OA-indicated anabolic (Acan) and catabolic (Adamts5) factor transcription levels in chondrocytes provided evidence regarding CoA and nanogel interactions. Thus, this sensor offers potential usage in simple and sensitive OA diagnostics.

A Preliminary Study of Quantitative MRI Cartilage Loss Fraction and Its Association With Future Arthroplasty Using the Osteoarthritis Initiative Database

Background and objective  Osteoarthritis (OA) is the most common arthritis in the world. Despite the high disease burden, there is no therapy to prevent, halt, or reverse OA, and many clinical trials relied on radiographic biomarkers for therapy response. It is important to identify patients with early OA who will eventually need arthroplasty, the end-stage treatment for osteoarthritis. This pilot study evaluates a novel MRI biomarker, cartilage loss fraction, for association with future arthroplasty and evaluates its feasibility of use and effect size estimates. Materials and methods Publicly available knee MRIs from the Osteoarthritis Initiative were used. A total of 38 participants with Kellgren-Lawrence (K-L) grade >1 and 38 participants with K-L grade ≤ 1 at enrollment were matched in age, sex, race, and BMI, and assessed for the degree of full-thickness cartilage loss, or cartilage loss fraction. Univariate conditional logistic regression analysis was performed for differences in cartilage loss fractions between groups. Receiver operating characteristic (ROC) curve analysis was performed to assess the association of MRI biomarkers and knee arthroplasty during the eight-year follow-up. Results The medial femoral condyle, medial tibial plateau, total, and two-year progression cartilage loss fractions were significantly higher in participants with K-L grade >1 (p < 0.01 for all) and showed high area under the curve (AUC) values on ROC analysis (812, 0.827, 0.917, and 0.933, respectively). These results were comparable or more strongly associated with other OA grading schemes. Conclusion MRI biomarker cartilage loss fractions are significantly higher in subjects with K-L grade >1 and show a strong association with arthroplasty. After further validation, cartilage loss fracture may be used to predict future arthroplasty.

Tissue engineering and future directions in regenerative medicine for knee cartilage repair: a comprehensive review

This review evaluates the current landscape and future directions of regenerative medicine for knee cartilage repair, with a particular focus on tissue engineering strategies. In this context, scaffold-based approaches have emerged as promising solutions for cartilage regeneration. Synthetic scaffolds, while offering superior mechanical properties, often lack the biological cues necessary for effective tissue integration. Natural scaffolds, though biocompatible and biodegradable, frequently suffer from inadequate mechanical strength. Hybrid scaffolds, combining elements of both synthetic and natural materials, present a balanced approach, enhancing both mechanical support and biological functionality. Advances in decellularized extracellular matrix scaffolds have shown potential in promoting cell infiltration and integration with native tissues. Additionally, bioprinting technologies have enabled the creation of complex, bioactive scaffolds that closely mimic the zonal organization of native cartilage, providing an optimal environment for cell growth and differentiation. The review also explores the potential of gene therapy and gene editing techniques, including CRISPR-Cas9, to enhance cartilage repair by targeting specific genetic pathways involved in tissue regeneration. The integration of these advanced therapies with tissue engineering approaches holds promise for developing personalized and durable treatments for knee cartilage injuries and osteoarthritis. In conclusion, this review underscores the importance of continued multidisciplinary collaboration to advance these innovative therapies from bench to bedside and improve outcomes for patients with knee cartilage damage.

Induced pluripotent stem cells in cartilage tissue engineering: a literature review

Osteoarthritis (OA) is a long-term, persistent joint disorder characterized by bone and cartilage degradation, resulting in tightness, pain, and restricted movement. Current attempts in cartilage regeneration are cell-based therapies using stem cells. Multipotent stem cells, such as mesenchymal stem cells (MSCs), and pluripotent stem cells, such as embryonic stem cells (ESCs), have been used to regenerate cartilage. However, since the discovery of human-induced pluripotent stem cells (hiPSCs) in 2007, it was seen as a potential source for regenerative chondrogenic therapy as it overcomes the ethical issues surrounding the use of ESCs and the immunological and differentiation limitations of MSCs. This literature review focuses on chondrogenic differentiation and 3D bioprinting technologies using hiPSCS, suggesting them as a viable source for successful tissue engineering.

METHODS

A literature search was conducted using scientific search engines, PubMed, MEDLINE, and Google Scholar databases with the terms 'Cartilage tissue engineering' and 'stem cells' to retrieve published literature on chondrogenic differentiation and tissue engineering using MSCs, ESCs, and hiPSCs.

RESULTS

hiPSCs may provide an effective and autologous treatment for focal chondral lesions, though further research is needed to explore the potential of such technologies.

CONCLUSIONS

This review has provided a comprehensive overview of these technologies and the potential applications for hiPSCs in regenerative medicine.

Exosome miR-4738-3p-mediated regulation of COL1A2 through the NF-κB and inflammation signaling pathway alleviates osteoarthritis low-grade inflammation symptoms

This study aimed to elucidate the roles of microRNA (miR)-4738-3p and the collagen type I alpha 2 chain (COL1A2) gene in the pathogenesis of osteoarthritis (OA) through bioinformatics analysis and cellular assays. The GSE55235 dataset was analyzed using the weighted gene co-expression network analysis (WGCNA) method to identify gene modules associated with OA. Key overlapping genes were identified from these modules and the GSE55235-differential expressed genes (DEGs). The expression levels of selected genes were determined in C28/I2 cells using the quantitative real-time polymerase chain reaction (qRT-PCR). The interaction between miR-4738-3p and COL1A2 was examined in the context of interleukin 1 beta (IL-1β) induction. Exosome characterization was achieved through transmission electron microscopy (TEM), western blotting (WB), and other analyses. The study also investigated the functional relevance of miR-4738-3p in OA pathology through various molecular and cellular assays. Our findings revealed that the green module exhibited a strong correlation with the OA phenotype in the GSE55235 dataset, with COL1A2 emerging as a hub gene and miR-4738-3p as its key downstream target. IL-1β induction suggested that COL1A2 is involved in inflammation and apoptosis, while miR-4738-3p appeared to play an antagonistic role. The analysis of exosomes underscored the significance of miR-4738-3p in cellular communication, with an enhanced level of exo-miR-4738-3p antagonizing IL-1β-induced inflammation and promoting cell survival. Conversely, a reduction in exo-miR-4738-3p led to increased cell damage. This study established a clear regulatory relationship between miR-4738-3p and COL1A2, with the nuclear factor kappa B (NF-κB) signaling pathway playing a central role in this regulation. The miR-4738-3p significantly influences the OA-associated inflammation, primarily through modulation of COL1A2 and the NF-κB pathway. Therefore, targeting miR-4738-3p offers a potential therapeutic approach for OA, with exosome miR-4738-3p presenting a promising strategy.

Potential therapeutic strategies for osteoarthritis via CRISPR/Cas9 mediated gene editing

Osteoarthritis (OA) is an incapacitating and one of the most common physically degenerative conditions with an assorted etiology and a highly complicated molecular mechanism that to date lacks an efficient treatment. The capacity to design biological networks and accurately modify existing genomic sites holds an apt potential for applications across medical and biotechnological sciences. One of these highly specific genomes editing technologies is the CRISPR/Cas9 mechanism, referred to as the clustered regularly interspaced short palindromic repeats, which is a defense mechanism constituted by CRISPR associated protein 9 (Cas9) directed by small non-coding RNAs (sncRNA) that bind to target DNA through Watson-Crick base pairing rules where subsequent repair of the target DNA is initiated. Up-to-date research has established the effectiveness of the CRISPR/Cas9 mechanism in targeting the genetic and epigenetic alterations in OA by suppressing or deleting gene expressions and eventually distributing distinctive anti-arthritic properties in both in vitro and in vivo osteoarthritic models. This review aims to epitomize the role of this high-throughput and multiplexed gene editing method as an analogous therapeutic strategy that could greatly facilitate the clinical development of OA-related treatments since it's reportedly an easy, minimally invasive technique, and a comparatively less painful method for osteoarthritic patients.

Intraarticular monomethyl fumarate as a perspective therapy for osteoarthritis by macrophage polarization

BACKGROUND

Osteoarthritis (OA) is a chronic disease that may lead to joint structure degeneration, cartilage destruction, osteophyte formation, subchondral bone disruption, and pain. In this scenario, a higher proportion of the proinflammatory macrophage type 1 (M1) than the anti-inflammatory macrophage type 2 (M2) could be highlighted as a hallmark of OA progression. The balance between these two macrophage types emerges as a new therapeutic target in OA. This study aimed to evaluate the analgesia and macrophage profile in the treatment of experimental osteoarthritis (EOA) with systemic dimethyl fumarate (DMF) or local intra-articular monomethyl fumarate (MMF).

RESULTS

DMF via gavage or MMF via intra-articular in the right knee of EOA rats showed improvements in gait parameters and the nociceptive recovery of the mechanical threshold assessment by adapted electronic von Frey treatment on the twenty-first day (long-lasting phase). DMF treatment decreased proinflammatory TNF-α while increasing anti-inflammatory IL-10 cytokines from the macerated capsule on the fifth day (inflammatory phase). MMF treatment showed joint capsule mRNA extraction downregulating iNOS and TNF-α gene expression while upregulating IL-10 and MCP-1. However, CD206 was not significant but higher than untreated EOA rats' joints on the seventh day (inflammatory phase).

CONCLUSIONS

Our studies with EOA model induced by MIA suggest a new perspective for human treatment committed with OA based on macrophage polarization as a therapeutic target, switching the proinflammatory profile M1 to the anti-inflammatory profile M2 with DMF systematic or by MMF locally treatment according to the OA severity.

RNA-binding proteins potentially regulate the alternative splicing of apoptotic genes during knee osteoarthritis progression

BACKGROUND

Alternative splicing (AS) is a principal mode of genetic regulation and one of the most widely used mechanisms to generate structurally and functionally distinct mRNA and protein variants. Dysregulation of AS may result in aberrant transcription and protein products, leading to the emergence of human diseases. Although considered important for regulating gene expression, genome-wide AS dysregulation, underlying mechanisms, and clinical relevance in knee osteoarthritis (OA) remain unelucidated. Therefore, in this study, we elucidated and validated AS events and their regulatory mechanisms during OA progression.

RESULTS

In this study, we identified differentially expressed genes between human OA and healthy meniscus samples. Among them, the OA-associated genes were primarily enriched in biological pathways such as extracellular matrix organization and ossification. The predominant OA-associated regulated AS (RAS) events were found to be involved in apoptosis during OA development. The expression of the apoptosis-related gene BCL2L13, XAF1, and NF2 were significantly different between OA and healthy meniscus samples. The construction of a covariation network of RNA-binding proteins (RBPs) and RAS genes revealed that differentially expressed RBP genes LAMA2 and CUL4B may regulate the apoptotic genes XAF1 and BCL2L13 to undergo AS events during OA progression. Finally, RT-qPCR revealed that CUL4B expression was significantly higher in OA meniscus samples than in normal controls and that the AS ratio of XAF1 was significantly different between control and OA samples; these findings were consistent with their expected expression and regulatory relationships.

CONCLUSIONS

Differentially expressed RBPs may regulate the AS of apoptotic genes during knee OA progression. XAF1 and its regulator, CUL4B, may serve as novel biomarkers and potential therapeutic targets for this disease.

Rationally engineered novel AAV capsids for intra-articular gene delivery

Intra-articular adeno-associated virus (AAV) gene therapy has been explored as a potential strategy for joint diseases. However, concerns of low transduction efficacy, off-target expression, and neutralizing antibodies (Nabs) still need to be addressed. In this study, we demonstrated that AAV6 was the best serotype to transduce joints after screening serotypes 1 to 9. To develop a more effective AAV vector, a set of novel AAV capsids were rationally engineered. The mutant AAV62 created by swapping variable region I (VRI) of AAV2 into AAV6 induced a higher transduction efficiency per AAV genome copy number. To further investigate the roles of specific amino acids in the transduction of AAV62 and AAV6, we found out that AAV6D with the deletion of threonine at residue 265 induced a 2-fold higher transduction than AAV6, while the transduction efficiency from AAV6M with the mutation of alanine to glutamine at residue 263 was 10-fold lower. AAV6D efficiently transduced both synoviocytes and chondrocytes with low AAV genome copy numbers in other tissues and less Nab formation. This study demonstrates that novel AAV mutants with rational engineering may enhance joint transduction after intra-articular administration in mice, with the potential to evade AAV Nabs and minimize off-target effects in the liver.

The role of inflammatory mediators and matrix metalloproteinases (MMPs) in the progression of osteoarthritis

Osteoarthritis (OA) is a chronic musculoskeletal disorder characterized by an imbalance between (synthesis) and catabolism (degradation) in altered homeostasis of articular cartilage mediated primarily by the innate immune system. OA degenerates the joints resulting in synovial hyperplasia, degradation of articular cartilage with damage of the structural and functional integrity of the cartilage extracellular matrix, subchondral sclerosis, osteophyte formation, and is characterized by chronic pain, stiffness, and loss of function. Inflammation triggered by factors like biomechanical stress is involved in the development of osteoarthritis. In OA apart from catabolic effects, anti-inflammatory anabolic processes also occur continually. There is also an underlying chronic inflammation present, not only in cartilage tissue but also within the synovium, which perpetuates tissue destruction of the OA joint. The consideration of inflammation in OA considers synovitis and/or other cellular and molecular events in the synovium during the progression of OA. In this review, we have presented the progression of joint degradation that results in OA. The critical role of inflammation in the pathogenesis of OA is discussed in detail along with the dysregulation within the cytokine networks composed of inflammatory and anti-inflammatory cytokines that drive catabolic pathways, inhibit matrix synthesis, and promote cellular apoptosis. OA pathogenesis, fluctuation of synovitis, and its clinical impact on disease progression are presented here along with the role of synovial macrophages in promoting inflammatory and destructive responses in OA. The role of interplay between different cytokines, structure, and function of their receptors in the inter-cellular signaling pathway is further explored. The effect of cytokines in the increased synthesis and release of matrix-decomposing proteolytic enzymes, such as matrix metalloproteinase (MMPs) and a disintegrin-like and metalloproteinase with thrombospondin motif (ADAMTS), is elaborated emphasizing the potential impact of MMPs on the chondrocytes, synovial cells, articular and periarticular tissues, and other immune system cells migrating to the site of inflammation. We also shed light on the pathogenesis of OA via oxidative damage particularly due to nitric oxide (NO) via its angiogenic response to inflammation. We concluded by presenting the current knowledge about the tissue inhibitors of metalloproteinases (TIMPs). Synthetic MMP inhibitors include zinc binding group (ZBG), non-ZBG, and mechanism-based inhibitors, all of which have the potential to be therapeutically beneficial in the treatment of osteoarthritis. Improving our understanding of the signaling pathways and molecular mechanisms that regulate the MMP gene expression, may open up new avenues for the creation of therapies that can stop the joint damage associated with OA.

Nanoparticle-based inhibition of vascular endothelial growth factor receptors alleviates osteoarthritis pain and cartilage damage

Osteoarthritis (OA) is characterized by cartilage damage, inflammation, and pain. Vascular endothelial growth factor receptors (VEGFRs) have been associated with OA severity, suggesting that inhibitors targeting these receptors alleviate pain (via VEGFR1) or cartilage degeneration (via VEGFR2). We have developed a nanoparticle-based formulation of pazopanib (Votrient), an FDA-approved anticancer drug that targets both VEGFR1 and VEGFR2 (Nano-PAZII). We demonstrate that a single intraarticular injection of Nano-PAZII can effectively reduce joint pain for a prolonged time without substantial side effects in two different preclinical OA rodent models involving either surgical (upon partial medial meniscectomy) or nonsurgical induction (with monoiodoacetate). The injection of Nano-PAZII blocks VEGFR1 and relieves OA pain by suppressing sensory neuronal ingrowth into the knee synovium and neuronal plasticity in the dorsal root ganglia and spinal cord. Simultaneously, the inhibition of VEGFR2 reduces cartilage degeneration. These findings provide a mechanism-based disease-modifying drug strategy that addresses both pain symptoms and cartilage loss in OA.

Advancements in tissue engineering for articular cartilage regeneration

Articular cartilage injury is a prevalent clinical condition resulting from trauma, tumors, infection, osteoarthritis, and other factors. The intrinsic lack of blood vessels, nerves, and lymphatic vessels within cartilage tissue severely limits its self-regenerative capacity after injury. Current treatment options, such as conservative drug therapy and joint replacement, have inherent limitations. Achieving perfect regeneration and repair of articular cartilage remains an ongoing challenge in the field of regenerative medicine. Tissue engineering has emerged as a key focus in articular cartilage injury research, aiming to utilize cultured and expanded tissue cells combined with suitable scaffold materials to create viable, functional tissues. This review article encompasses the latest advancements in seed cells, scaffolds, and cytokines. Additionally, the role of stimulatory factors including cytokines and growth factors, genetic engineering techniques, biophysical stimulation, and bioreactor systems, as well as the role of scaffolding materials including natural scaffolds, synthetic scaffolds, and nanostructured scaffolds in the regeneration of cartilage tissues are discussed. Finally, we also outline the signaling pathways involved in cartilage regeneration. Our review provides valuable insights for scholars to address the complex problem of cartilage regeneration and repair.

Current state of systematic reviews for platelet-rich plasma use in knee osteoarthritis

BACKGROUND

Knee osteoarthritis (KOA) is a highly prevalent musculoskeletal disorder affecting millions of people. To date, there is no curative treatment for KOA other than joint arthroplasty. However, treatments such as platelet-rich plasma (PRP) have been proposed as a possible therapy, with increasing interest over the last decade. To date, there are no evidence-based guidelines in the use of PRP therapy for KOA, but there are numerous studies and systematic reviews (SRs) evaluating the usage of PRP in KOA. Since SRs are of great importance for clinical decision-making, it is necessary to access their methodological quality before any valid conclusions can be made. This study will evaluate the methodological quality of SRs on PRP therapy for KOA using a validated assessment tool known as AMSTAR 2, "A MeaSurement Tool to Assess systematic Reviews".

HYPOTHESIS

It is hypothesized that the methodological quality of SRs will be moderate, whereby most of the SRs will provide an accurate summary of the results but will include more than one critical weakness as defined by the AMSTAR 2 checklist.

PATIENTS AND METHODS

The MEDLINE, EMBASE, PubMed and Cochrane databases were searched from inception to May 2023. Two independent reviewers selected SRs that investigated the use of injection therapies for KOA. Descriptive statistical analysis was performed. AMSTAR 2 assessment was completed independently by the same reviewers. Cohen's kappa was calculated to measure interrater reliability. The quality of the studies was rated as "high", "moderate", "low", and "critically low". The overall confidence assessment was tabulated.

RESULTS

Forty-one SRs were included in the analysis. The Cohen kappa was 0.88, indicating high interrater reliability. There were no "high" quality SRs identified. Seven SRs (17%) were of "low" quality, while the remainder (34 SRs, 83%) were rated as "critically low".

CONCLUSION

The methodological quality of the selected SRs was suboptimal. Clinicians should critically appraise the SRs and interpret their conclusions with caution before making clinical decisions. This study supports future work of high-quality SRs regarding the use of PRP injections for KOA.

LEVEL OF EVIDENCE

II.

Devices for osteoarthritis symptoms treatment: a patent review

INTRODUCTION

Osteoarthritis is a musculoskeletal disease that can lead to the loss and inability of those affected to perform normal daily functions, which leads to a decrease in quality of life. The main symptoms of osteoarthritis are tenderness, joint pain, stiffness, crepitus, limited movement, and local inflammation.

AREAS COVERED

The selected patents were deposited from 2010 to April 2022 involving 57 documents that were in line with the study objective in the final selection. The patents were classified in years, country, and applicants. Also, the therapeutic fields that presented the most documents were electrical stimulation, phototherapy, and ultrasound, followed by magnetic, electromagnetic, and thermotherapy. Therefore, the most current therapies used in the documents are already on the market.

EXPERT OPINION

Although the OA is cureless, non-surgical treatments are classified as the primary management approach for this disease. The pharmacological and non-pharmacological therapies are employed to reduce its prevalence and ensure the effectiveness of treatments. A strategy for relieving OA symptoms is non-pharmacological treatment, which can be based on exercise and patient education, combined with other alternative therapies. These therapies are used as supplements to the main OA treatments, enhancing the effectiveness of treatment outcomes.

The Pharmacological Potential of Resveratrol in Reducing Soft Tissue Damage in Osteoarthritis Patients

Osteoarthritis is a degenerative joint disease that causes the cartilage and bone underneath the joint to break down. This causes pain and stiffness. Resveratrol, a polyphenolic compound found in various vegetables, fruits, and red wine, has been studied for its beneficial effects on osteoarthritis. Resveratrol has been shown to target a variety of pathways, including the NF-κB, PI3K/Akt, MAPK/ERK, and AMPK pathways. In particular, resveratrol has been studied for its potential use in treating osteoarthritis, and it has been shown to reduce inflammation, reduce cartilage degradation, and improve joint function. In this review, we discuss the evidence for the pharmacological use of resveratrol in minimizing soft tissue damage associated with osteoarthritis. We summarize the studies on how resveratrol has anti-inflammatory, anti-oxidant, and anti-apoptotic effects, as well as effects on cartilage degradation, osteoblast and synoviocyte proliferation, and cytokine production. We also discuss the possible mechanisms of action of resveratrol in osteoarthritis and its potential as a therapeutic agent. Finally, we discuss the potential risks and adverse effects of long-term resveratrol supplementation. Overall, resveratrol has been found to be a possible treatment for osteoarthritis because of its anti-inflammatory, anti-oxidant, and anti-apoptotic properties, and its ability to control the production of enzymes that break down cartilage, osteoblasts, and synoviocytes. Although numerous clinical studies have demonstrated resveratrol's efficacy as an osteoarthritis management agent, further long-term studies are needed to better understand the safety and potential benefits of using resveratrol for osteoarthritis management.

A Comprehensive Review on the Regulatory Action of TRP Channels: A Potential Therapeutic Target for Nociceptive Pain

The transient receptor potential (TRP) superfamily of ion channels in humans comprises voltage-gated, non-selective cation channels expressed both in excitable as well as non-excitable cells. Four TRP channel subunits associate to create functional homo- or heterotetramers that allow the influx of calcium, sodium, and/or potassium. These channels are highly abundant in the brain and kidney and are important mediators of diverse biological functions including thermosensation, vascular tone, flow sensing in the kidney and irritant stimuli sensing. Inherited or acquired dysfunction of TRP channels influences cellular functions and signaling pathways resulting in multifaceted disorders affecting skeletal, renal, cardiovascular, and nervous systems. Studies have demonstrated the involvement of these channels in the generation and transduction of pain. Based on the multifaceted role orchestrated by these TRP channels, modulation of the activity of these channels presents an important strategy to influence cellular function by regulating intracellular calcium levels as well as membrane excitability. Therefore, there has been a remarkable pharmaceutical inclination toward TRP channels as therapeutic interventions. Several candidate drugs influencing the activity of these channels are already in the clinical trials pipeline. The present review encompasses the current understanding of TRP channels and TRP modulators in pain and pain management.

Understanding the role of exosomal lncRNAs in rheumatic diseases: a review

Rheumatic diseases, a group of diseases whose etiology is still unclear, are thought to be related to genetic and environmental factors, leading to complex pathogenesis. Based on their multi-system involvement, the diagnosis and treatment continue to face huge challenges. Whole-genome assays provide a distinct direction for understanding the underlying mechanisms of such diseases. Exosomes, nano-sized bilayer membrane vesicles secreted by cells, are mentioned as a key element in the physiological and pathological processes of the body. These exosomes mediate biologically active substances, such as nucleic acids, proteins, and lipids and deliver them to cells. Notably, long non-coding RNAs (lncRNAs), a unique class of non-coding RNAs, have been implicated in the pathogenesis of rheumatic diseases. However, the mechanism needs to be further explored. This article provided a comprehensive review of the findings on exosomal lncRNAs in rheumatic diseases, including rheumatoid arthritis, osteoarthritis, systemic lupus erythematosus, autoimmune liver diseases, primary dermatomyositis, and systemic sclerosis. Through in-depth understanding of these lncRNAs and their involved signaling pathways provide new theoretical supports for the diagnosis and treatment of rheumatic diseases.